REVIEW | doi:10.20944/preprints201903.0267.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: hepatocellular carcinoma, gut microbiota, gut-liver axis, intestinal dysbiosis
Online: 28 March 2019 (13:43:07 CET)
Hepatocellular carcinoma (HCC), one of the leading causes of death worldwide, has a causal nexus with liver injury, inflammation, and regeneration that accumulate over decades. Observations from recent studies have accounted for the involvement of the gut-liver axis in the pathophysiological mechanism responsible for HCC. The human intestine nurtures a diversified colony of microorganisms residing in the host ecosystem. The intestinal barrier is critical for conserving the normal physiology of the gut microbiome. Therefore, a rupture of this barrier or dysbiosis cause the intestinal microbiome to serve as the main source of portal-vein endotoxins such as lipopolysaccharide, in the progression of hepatic diseases. Indeed, increased bacterial translocation is a key sign of HCC. Considering the limited number of clinical studies on HCC with respect to the microbiome, we focus on the clinical as well as animal studies involving the gut microbiota with the current understandings of the mechanism by which the intestinal dysbiosis promotes hepatocarcinogenesis. Future research might offer mechanistic insights into the specific phyla targeting the leaky gut, as well as microbial dysbiosis, and their metabolites, as key pathways that drive HCC-promoting microbiome-mediated liver inflammation and fibrosis, thereby restoring the gut barrier function.
REVIEW | doi:10.20944/preprints201811.0171.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: Autism, ASD, microbiota, gut-brain-axis, microbiota-gut-brain-axis, therapy
Online: 7 November 2018 (14:45:10 CET)
New research points to a possible link between Autism Spectrum Disorder and the gut microbiota as many autistic children have co-occurring gastrointestinal problems. This review focuses on specific alterations of gut microbiota mostly observed in autistic patients. Particularly, the mechanisms through which such alterations may trigger the production of the bacterial metabolites or leaky gut in autistic people are described. Various altered metabolite levels were observed in autistic children, many of those were of bacterial origin such as short chain fatty acids (SCFAs), indoles and lipopolysaccharides. A less integrative gut-blood-barrier is abundant in autistic individuals. This explains the leakage of bacterial metabolites into the patients triggering new body responses or altered metabolism. Some other co-occurring symptoms such as mitochondrial dysfunction, oxidative stress in the cells, altered tight junctions in the blood brain barrier and structural changes in cortex, hippocampus, amygdala and cerebellum were detected. Moreover, this paper suggests that autism is associated with an unbalanced gut microbiota (dysbiosis). Although the cause-effect relationship between autism and gut microbiota is not yet well established, consumption of specific probiotics may represent a powerful tool to re-establish gut homeostasis and promote gut health. Diagnostic and therapeutic value of new biomarkers leading to the perturbation in the phenylalanine metabolism will be discussed.
REVIEW | doi:10.20944/preprints202011.0683.v1
Subject: Medicine & Pharmacology, Allergology Keywords: gut microbiota; early-life gut microbiota; gut dysbiosis; long-term health and disease; Developmental Origins of Health and Disease (DOHaD)
Online: 27 November 2020 (11:22:07 CET)
Abstract: Early life gut microbiota have been increasingly recognized as major contributors to short and/or long-term human health and diseases. Numerous studies have demonstrated that human gut microbial colonization begins at birth but continues to develop a succession of taxonomic abundances for two to three years until the gut microbiota reaches adult-like diversity and proportions. Several factors, including gestational age (GA), delivery mode, birth weight, feeding types, antibiotic exposure, maternal microbiome and diet influence the diversity, abundance and function of the early life gut microbiota. Gut microbial life is essential for assisting with the digestion of food substances to release nutrients, exerting control over pathogens, stimulating or modulating the immune system and influencing many systems such as the liver, brain, and endocrine system. Microbial metabolites play multiple roles in these interactions. Furthermore, studies provide evidence supporting that imbalances of the gut microbiota in early life, referred to as dysbiosis, are associated with specific childhood or adult disease outcomes, such as asthma, atopic dermatitis, diabetes, allergic diseases, obesity, cardiovascular diseases (CVD) and neurological disorders. These findings support that the human gut microbiota may play a fundamental role in the risk of acquiring diseases that may be programmed during the early life stage. In fact, it is critical to explore the role of the human gut microbiota in early life. In this review, we summarize the general understanding of the colonization and development of the gut microbiota in early life, highlighting the recent findings regarding the relationship between the gut microbiota composition and their metabolites, and immune functions, which could significantly influence long-term health and disease. We then review known pathophysiological interactions of the early gut microbiome with a number of well characterized diseases and pose potential etiological mechanisms.
REVIEW | doi:10.20944/preprints202210.0465.v1
Subject: Life Sciences, Microbiology Keywords: Gut-bone axis; Gut-brain axis; Microbiome; Probiotics; Osteoporosis
Online: 31 October 2022 (06:16:35 CET)
The gut microbiome is a collection of microorganisms and parasites that reside in the gastrointestinal tract. There are many factors that can affect the composition of this community, such as age, sex, medications, and environmental triggers. The relationship between the human host and the gut microbiota is very important for both the survival and development of the organism. The disruption of this relationship can lead to the development of various inflammatory diseases. CBD and THC are used to treat muscle spasticity associated with multiple sclerosis. It is now clear these compounds also benefit patients with neuroinflammation. A study that investigated the role of gut microbiota in treating the inflammation and paralysis in a mouse model demonstrated that treatment with CBD and THC produced significant decrease in the inflammation levels. They also exhibited a significant increase in the number of anti-inflammatory cytokines. The presence of certain cannabinoids can suppress neuroinflammation and prevent microbial dysbiosis. Several studies have revealed the role of the gut microbiota in the development and maintenance of skeletal integrity and bone mineral density. The gut is a major source of nutrients, including vitamins B and K. It can also influence the development and maintenance of bone matrix. The presence of the gut microbiota can influence the actions of certain T regulatory cells, which can lead to the development of bone formation and proliferation. In addition, its metabolites can prevent bone loss. The gut microbiota can help maintain the bone's equilibrium and prevent the development of metabolic diseases, such as osteoporosis. In this review, the dual functions gut microbiota plays in the regulation of gut-bone axis and gut-brain axis and the impact of CBD on these roles are discussed in detail.
Subject: Medicine & Pharmacology, Nutrition Keywords: renal diets; fiber; renal nutrition; chronic kidney disease; gut microbiota
Online: 26 August 2019 (12:23:22 CEST)
Nutrition is crucial for the management of patients affected by chronic kidney disease (CKD) to slow down disease progression and to correct symptoms. The mainstay of the nutritional approach to renal patients is protein restriction coupled with adequate energy supply to prevent malnutrition. However, other aspects of renal diets, including fiber content, can be beneficial. This paper summarizes the latest literature on the role of different types of dietary fiber in CKD, with special attention to intestinal microbiota and the potential protective role of renal diets. Fibers have been identified based on aqueous solubility, but other features, such as viscosity, fermentability, and bulking effect in the colon should be considered. A proper amount of fiber should be recommended not only in the general population but also in CKD patients, to achieve an adequate composition and metabolism of intestinal microbiota and to reduce the risks connected with obesity, diabetes, and dyslipidemia.
REVIEW | doi:10.20944/preprints202112.0045.v1
Online: 3 December 2021 (09:57:35 CET)
Rotavirus (RV) and norovirus (NoV) are the leading cause of acute gastroenteritis (AGE) worldwide. Several studies have demonstrated that histo-blood group antigens (HBGAs) have a role in NoV and RV infections, since their presence on the gut epithelial surfaces is essential for the susceptibility to many NoV and RV genotypes. Polymorphisms in genes that code for enzymes required for HBGAs synthesis lead to secretor or non-secretor and Lewis positive and Lewis negative individuals. While secretor individuals appear to be more susceptible to RV infections, regarding NoVs infections there are too many discrepancies that prevent drawing conclusions. A second factor that influences enteric viral infections is the gut microbiota of the host. In vitro and animal studies have determined that the gut microbiota limits, but in some cases enhances, enteric viral infection. The ways microbiota can enhance NoV or RV infection include virion stabilization and promotion of virus attachment to host cells, whereas experiments with microbiota-depleted and germ-free animals point to immunoregulation as the mechanism by which the microbiota restricts infection. Human trials with live, attenuated RV vaccines and analysis of the microbiota in responders and non-responders individuals also allowed the identification of bacterial taxa linked to vaccine efficacy. As more information is gained on the complex relationships that are established between the host (glycobiology and immune system), the gut microbiota and the intestinal viruses, new avenues will be open for the development of novel anti-NoV and anti-RV therapies.
REVIEW | doi:10.20944/preprints202210.0210.v1
Subject: Biology, Other Keywords: Obesity; gut microbiota; placenta; brain development; fatal development
Online: 14 October 2022 (10:15:21 CEST)
Obesity in pregnancy induces metabolic syndrome, low-grade inflammation, altered endocrine factors, placental function, and the maternal gut microbiome. All these factors impact fetal growth and development, including brain development. The lipid metabolic transporters of the maternal-fetal-placental unit are dysregulated in obesity. Consequently, the transport of essential long-chain PUFAs for fetal brain development is disturbed. The mother’s gut microbiota is vital in maintaining postnatal energy homeostasis and maternal-fetal immune competence. Obesity during pregnancy changes the gut microbiota, affecting fetal brain development. Obesity and a high-fat diet in pregnancy can induce placental and intrauterine inflammation and thus influence the neurodevelopmental outcomes of the offspring. Several epidemiological studies observed an association between maternal obesity and adverse neurodevelopment. This review discusses the effects of maternal obesity and gut microbiota on fetal neurodevelopment outcomes. In addition, the possible mechanisms of the impacts of obesity and gut microbiota on fetal brain development are discussed.
ARTICLE | doi:10.20944/preprints202003.0388.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: celiac disease; gut microbiota; mendelian randomization
Online: 26 March 2020 (14:08:31 CET)
Celiac disease (CeD) is a complex immune-mediated inflammatory condition triggered by ingestion of gluten in genetically predisposed individuals. Literature suggests that alterations in gut microbiota composition and function precede the onset of CeD. Considering that microbiota is partly determined by host genetics, we speculate that the genetic makeup of CeD patients could elicit disease development through alterations in the intestinal microbiota. To evaluate potential causal relationships between gut microbiota and CeD, we performed a Two-Sample Mendelian Randomization analysis (2SMR). Exposure data were obtained from the raw results of a previous Genome Wide Association Study (GWAS) of gut microbiota, and outcome data from summary statistics of CeD GWAS and Immunochip studies. We have identified a number of putative associations between gut microbiota SNPs associated with CeD. Regarding bacterial composition, most of the associated SNPs are related to Firmicutes phylum, whose relative abundance has been previously reported to be altered in CeD patients. In terms of functional units, we have linked a number of SNPs to several bacterial metabolic pathways that seem to be related to CeD. Overall, this study represents the first 2SMR approach to elucidate the relationship between microbiome and CeD.
REVIEW | doi:10.20944/preprints202002.0084.v1
Subject: Medicine & Pharmacology, Psychiatry & Mental Health Studies Keywords: depression; leaky gut; microbiota; cytokines; neuroimmunomodulation; oxidative stress
Online: 6 February 2020 (10:30:36 CET)
There is robust evidence that major depression (MDD) is accompanied by a low-grade activation of the immune-inflammatory response system, which is involved in the pathophysiology of this disorder. It is also becoming apparent that glia cells are in reciprocal communication with neurons and orchestrate various neuromodulatory, homeostatic, metabolic, and immune mechanisms and have a crucial role in neuroinflammatory mechanisms in MDD. Those cells mediate the central nervous system (CNS) response to systemic inflammation and psychological stress, but at the same time, they may be an origin of the inflammatory response in the CNS. The sources of activation of the inflammatory response in MDD are immense, however, in recent years, it is becoming increasingly evident that the gastrointestinal tract with gut-associated lymphoid tissue (GALT) and increased intestinal permeability to bacterial LPS and food-derived antigens contribute to activation of low-grade inflammatory response with subsequent psychiatric manifestations. Furthermore, an excessive permeability to gut-derived antigenic material may lead to subsequent autoimmunities which are also known to be comorbid with MDD. In this chapter, we discuss fascinating interactions between the gastrointestinal tract, increased intestinal permeability, intestinal microbiota, and glia-neuron crosstalk, and their roles in the pathogenesis of the inflammatory hypothesis of MDD. To emphasize those crucial intercommunications for the brain functions, we propose the term of microbiota-gut-immune-glia (MGIG) axis.
REVIEW | doi:10.20944/preprints201709.0040.v2
Subject: Life Sciences, Endocrinology & Metabolomics Keywords: Gut microbiota; obesity; insulin resistance, NAFLD; probiotic; prebiotic; symbiotic
Online: 6 October 2017 (16:15:42 CEST)
Gut microbiota play critical roles in development of obese-related metabolic diseases such as nonalcoholic fatty liver disease (NAFLD), type 2 diabetes, and insulin resistance, which highlighted the potential of gut microbiota-targeted therapies on these diseases. There are various ways that can manipulate gut microbiota including probiotics, prebiotics, synbiotics, antibiotics and some active components from herbal medicines. In this review, we first reviewed the main roles of gut microbiota in mediating the development of NAFLD, and the advances in gut microbiota-targeted therapies on NAFLD in both the experimental and clinical studies, as well as the conclusions on the prospect of gut microbiota-targeted therapies in the future.
ARTICLE | doi:10.20944/preprints202002.0082.v1
Subject: Medicine & Pharmacology, Psychiatry & Mental Health Studies Keywords: gut microbiota; ADHD; 16S rRNA gene; Inattention
Online: 6 February 2020 (10:25:29 CET)
Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder. Given the growing evidence of gut microbiota being involved in psychiatric (including neurodevelopmental) disorders, we aimed to identify differences in gut microbiota composition between participants with ADHD and controls and to investigate the role of the microbiota in inattention and hyperactivity/impulsivity. Fecal samples were collected from 107 participants (NADHD=42; Ncontrols=50; NsubthreholdADHD=15; range age: 13-29 years). The relative quantification of bacterial taxa was done using 16S ribosomal RNA gene amplicon sequencing. Beta-diversity revealed significant differences in bacterial composition between participants with ADHD and healthy controls, which was also significant for inattention, but showing a trend in case of hyperactivity/impulsivity only. Ten genera showed nominal differences (P < 0.05) between both groups, of which seven genera were tested for their association with ADHD symptom scores (adjusting for age, sex, body mass index, time delay between feces collection and symptoms assessment, medication use and family relatedness). Our results show that variation of a genus from the Ruminococcaceae family (Ruminococcaceae_UCG_004) is associated (after multiple testing correction) with inattention symptoms, and suggest a role of gut microbiota in ADHD pathophysiology.
ARTICLE | doi:10.20944/preprints201912.0315.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: Lactobacillus; piglet; weaning; gut microbiota; growth enhancement.
Online: 24 December 2019 (10:59:14 CET)
The composition of bacteria in the gastrointestinal tract of piglets is easily affected by environmental changes, particularly during the weaning period. Compound strains of Lactobacillus reuteri and Lactobacillus salivarius were supplemented to piglets during pre- and post-weaning to determine their effects in improving the growth performance and ameliorating the diarrhea rate and stress caused by antioxidation in piglets. A larger number of L. reuteri and L. salivarius colonized the distal segment of the ileum and the total numbers of Lactobacillus spp. and Bifidobacterium were higher in the ileal mucous membrane and cecal lumen with probiotics supplementation. The numbers of antioxidative and immune molecules were increased in the plasma following compound bacteria (CL) supplementation, whereas cortisol and endotoxin levels were lower and growth hormone and insulin-like growth factor 1 were higher. Spearman’s and KEGG analysis of the bacterial operational taxonomic unit and antioxidative and immune indices and metabolic genes indicated that the body growth modulation by CL supplementation could be attributed to optimization of the intestinal bacterial composition. Collectively, these results suggest that supplementation with CL could reduce stress and improve the growth performance of piglets during weaning by optimizing the intestinal bacterial composition.
REVIEW | doi:10.20944/preprints202211.0303.v1
Subject: Medicine & Pharmacology, Psychiatry & Mental Health Studies Keywords: gut-brain-axis; BDNF; bacteria; neuron; neurotrophin; hippocampus
Online: 16 November 2022 (09:54:53 CET)
Growing evidence suggests a possible involvement of the intestinal microbiota in generating new neurons, but a detailed breakdown of the microbiota composition is lacking. In this report, we systematically reviewed preclinical rodent reports addressing the connection between the composition of the intestinal microbiota and neurogenesis and neurogenesis-affecting neurotrophins in the hippocampus. Various changes in bacterial composition from low taxonomic resolution at the phylum level to high taxonomic resolution at the species level were identified. As for neurogenesis, studies predominantly used doublecortin (DCX) as a marker of newly formed neurons or bromodeoxyuridine (BrdU) as a marker of proliferation. Brain-derived neurotrophic factor (BDNF) was the only neurotrophin found researched in relation to the intestinal microbiota. Phylum Actinobacteria, genus Bifidobacterium and genus Lactobacillus found the strongest positive while phylum Firmicutes, phylum Bacteroidetes and family Enterobacteriaceae as well as germ-free status, showed the strongest negative correlation towards neurogenesis or BDNF mRNA expression. Age, short-chain fatty acids (SCFA), obesity and chronic stress were recurring topics in all studies identified. Overall, these findings add to the existing evidence of a connection between microbiota and processes in the brain. To better understand this interaction, further investigation based on analyses of higher taxonomic resolution and clinical studies would be a gain to the matter.
ARTICLE | doi:10.20944/preprints202105.0710.v1
Subject: Life Sciences, Biochemistry Keywords: Gut microbiota; Mycobiota; Bacteria; Fungi; Malaria; Plasmodium falciparum; 16S metagenomics; ITS metagenomics; Children; Cohort; Mali; Dogon country
Online: 31 May 2021 (08:25:57 CEST)
The gut microbiota has recently been associated with susceptibility/resistance to malaria in animal models and humans, yet the impact of the gut microbiota on the risk of a malaria attack remains to be assessed. This study aims at assessing the influence of the gut microbiota on malaria attacks and Plasmodium parasitæmia in children living in a malaria-endemic area in Mali. Three hundred healthy children were included in a 16-months cohort study in Bandiagara. Their gut bacteria and fungi community structures were characterised via 16S and ITS metabarcoding from stool samples collected at inclusion. Clinician team monitored the occurrence of malaria attacks. Asymptomatic carriage of Plasmodium was assessed by qPCR. Over the 16-month period, 107 (36%) children experienced at least one occurrence of malaria attacks, and 82 (27%) at least one asymptomatic Plasmodium parasitæmia episode. A higher gut bacteria richness was independently associated with susceptibility to asymptomatic parasitæmia episodes and malaria attacks; while the Shannon H diversity and Chao-1 richness index of gut fungi community structure was relatively homogeneous in children who were and were not infected with P. falciparum. Using a linear discriminant effect size analysis of operational taxonomic units assigned to the species level, 17 bacteria, including Clostridiaceae, Eubacteriaceae, Senegalimassilia sp., Atopobiaceae and Lachnosipraceae, and seven fungi, including Dioszegia fristigensis, Ogataea polymorpha and Cutaneotrichosporon cyanovorans, were associated with susceptibility; whereas eight bacteria, including, Bifidobacterium spp., Weissela confusa and Peptostreptococcacea, and 3 fungi, Malassezia sp., Niesslia exosporoides, and Didymocrea leucaenae, were associated with resistance to malaria. Moreover, 15 bacteria, including Coproccus eutactus, Terrisporobacter petrolearius, Klebsiella pneumoniae and Ruminococcaceae, and 13 fungi, including Wallemia mellicola, were associated with susceptibility, whereas 19 bacteria, including Bifidobacterium spp., Bacteroides fragilis, Peptostreptococcacea, and Lactobacillus ruminis, and three fungi, including Cryptococcus neoformans, were associated with resistance to asymptomatic Plasmodium parasitæmia episodes. Further studies are needed to confirm these findings that point the way towards strategies aiming to reduce the risk of malaria by modulating gut microbiota components in at-risk populations.
REVIEW | doi:10.20944/preprints201805.0404.v2
Subject: Life Sciences, Other Keywords: microbiota; kynurenine pathway; serotonin; inflammation; gut motility
Online: 22 June 2018 (06:29:42 CEST)
The human gastrointestinal tract is inhabited by trillions of commensal bacteria collectively known as the gut microbiota. Our recognition of the significance of the complex interaction between the microbiota, and its host has grown dramatically over the past years. A balanced microbial community is a key regulator of the immune response, and metabolism of dietary components, which in turn, modulates several brain processes impacting mood and behavior. Consequently, it is likely that disruptions within the composition of the microbiota would remotely affect the mental state of the host. Here, we discuss how intestinal bacteria and their metabolites can orchestrate gut-associated neuroimmune mechanisms that influence mood and behavior leading to depression. In particular, we focus on microbiota-triggered gut inflammation and its implications in shifting the tryptophan metabolism towards kynurenine biosynthesis while disrupting the serotonergic signaling. We further investigate the gaps to be bridged in this exciting field of research in order to clarify our understanding of the multifaceted crosstalk in the microbiota-gut-brain interphase, bringing about a novel microbiota-targeted therapeutics for mental illnesses.
Subject: Life Sciences, Biochemistry Keywords: gut microbiota; Entamoeba histolytica; resistance to oxidative stress; resistance to nitrosative stress; virulence
Online: 24 February 2021 (16:26:55 CET)
Amebiasis is a disease caused by the unicellular parasite Entamoeba histolytica. In most cases, the infection is asymptomatic but when symptomatic, the infection can cause dysentery and invasive extraintestinal complications. In the gut, E.histolytica feeds on bacteria. Increasing evidences support the role of the gut microbiota in the development of the disease. In this review we will discuss the consequences of E.histolytica infection on the gut microbiota. We will also discuss new evidences about the role of the gut microbiota in regulating the resistance of the parasite to oxi-dative stress and its virulence.
ARTICLE | doi:10.20944/preprints202007.0338.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: bacteriophage; Bifidobacterium; gut microbiota; intestinal health; microbiome; probiotic
Online: 15 July 2020 (12:32:41 CEST)
Probiotics are increasingly used by consumers and practitioners to reduce gastrointestinal (GI) distress and improve gut function. Here, we sought to determine whether addition of supplemental bacteriophages (PreforPro) could enhance the effects of a common probiotic, Bifidobacterium animalis subsp. lactis (B. lactis) on GI health. We conducted a 4-week, randomized, parallel-arm, double-blind, placebo-controlled trial where primary outcomes included self-assessments of GI health, a daily stool log, and 16s rRNA analysis of gut microbial populations. We observed within group improvements in GI inflammation (p=0.01) and a trending improvement in colon pain (p=0.08) in individuals consuming B. lactis with PreforPro, but not in the group consuming only the probiotic. There was also a larger increase in Lactobacillus and short chain fatty acid-producing microbial taxa detected in stool of participants taking PreforPro with B. lactis compared to the probiotic alone. Overall, these results suggest the addition of PreforPro as a combination therapy may alter gut ecology to extend the GI benefits of consuming B. lactis or other probiotics.
REVIEW | doi:10.20944/preprints202109.0288.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: Diet; Obesity; Gut microbes; High-fiber diet; High fat diet
Online: 16 September 2021 (13:50:36 CEST)
With the ever-increasing rate, obesity has become an epidemiological problem throughout the globe comprising about 39% of the world population as of now. Among several reasons, disruption of the gut microbial ecosystem might contribute to the pathogenesis of metabolic disorders, including obesity, metabolic syndrome, type 2 diabetes, and other associated comorbidities. Though the mechanisms related to dysbiosis are unclear, diet might play a modulating role where different dietary approaches manipulate microbial richness and abundance as well as stability. For instance, shifting of Firmicutes and Bacteroidetes ratio in the gut might have a role in association with the dietary approaches and ingestion duration. Along with altered gut microbial composition, microbial metabolites such as short-chain fatty acids (SCFA) after ingestion of non-digestible dietary starches may have an impact on host metabolism by regulating lipogenesis, gluconeogenesis, and inflammation with potential associations to health and obesity. The dietary approaches like carbohydrates, fibre, protein, and/or fat diet at various arrangements can make a shift in the composition of gut microbiota if introduced for a short period. However, the unique pattern of the gut microbes usually remains the same along with the longer period of habitual diet. Though the short-term dietary intervention or circadian rhythm influences a transient change in gut microbes, other than habitual diet, the understanding related to long-term dietary change-induced permanent alterations is minimum. Alternatively, the usage of prebiotics, probiotics as well as postbiotics could be beneficial to overcome dysbiosis. This review highlights the current knowledge and the interaction between the human intestinal microbiota and diet as a modifying factor, in obesity allowing the scientists to uncover novel targets and tools to use as customized therapy.
ARTICLE | doi:10.20944/preprints202002.0306.v1
Subject: Life Sciences, Microbiology Keywords: Egyptian mongoose; Gut microbiota; Microbial profiling; Bio-ecology; Mediterranean Wild Carnivores
Online: 21 February 2020 (08:02:59 CET)
Egyptian mongoose (Herpestes ichneumon) is a medium-size carnivore that in Europe is restricted to Iberia. The bio-ecology of this species remains to be elucidated in several dimensions, including gut microbiota that is nowadays recognized as a fundamental component of mammals. In this work, we investigated the gut microbiota of this herpestid by single-molecule real-time sequencing of twenty paired male (n=10) and female (n=10) intestinal samples. This culture-independent approach enabled microbial profiling based on 16S rDNA and investigation of taxonomical and functional features. The core gut microbiome of the adult subpopulation was dominated by Firmicutes, Fusobacteria, Actinobacteria, and Proteobacteria. Eight genera were uniquely found in adults and five in non-adults. When comparing gut bacterial communities across sex, four genera were exclusive of females and six uniquely found in males. Despite these compositional distinctions, alpha- and beta-diversity analyses showed no statistically significant differences across sex or between adult and non-adult specimens. However, males presented a significantly higher abundance of amino acid and citrate cycle metabolic pathways, compared to the significant overrepresentation in females of galactose’ metabolic pathways. Adults showed a significantly higher abundance of cationic antimicrobial peptide resistance pathways, while non-adults bared a significant overrepresentation of two-component systems associated with antibiotic synthesis, flagellin production and chemotaxis control. This study adds new insights into mongoose bio-ecology palette, highlighting taxonomical and functional microbiome dissimilarities across sex and age classes, possibly related to primary production resources and life-history traits that impact on behavior, diet and gut ecosystem.
REVIEW | doi:10.20944/preprints201612.0119.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: antibiotic; bacteroidetes; dietary emulsifier; firmicutes; food additive; gut microbiota; non-nutritive sweetener; proteobacteria
Online: 23 December 2016 (11:21:40 CET)
Gut bacteria play an important role in several metabolic processes and human diseases, such as obesity and its co-morbidities, like fatty liver disease, insulin resistance/diabetes and cardiovascular events. Among several factors, dietary patterns, probiotics, prebiotics, synbiotics, antimicrobials and non-dietary factors, such as stress, age, exercise and climatic conditions, can dramatically impact the human gut microbiota diversity and equilibrium. However, the effect of minor food constituents, including food additives and trace contaminants, on human gut microbiota has received less attention. Consequently, the present review aimed to provide an objective perspective of the current knowledge regarding the impacts of minor food constituents on human gut microbiota and consequently, on human health.
REVIEW | doi:10.20944/preprints201810.0369.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: Age-Related Macular Degeneration, Gut-retina axis, Gut microbiota, Dietary habits, Micronutrients, Fish oil, omega-3 Polyunsaturated fatty acids, Personalised medicine
Online: 16 October 2018 (17:39:27 CEST)
Age-related macular degeneration (AMD) is a complex multifactorial disease and the primary cause of legal and irreversible blindness among individuals aged >=65 years in developed countries. Globally, it affects 30-50 million individuals, with an estimated increase of approximately 200 million by 2020 and approximately 300 million by 2040. Currently, the neovascular form may be able to be treated with the use of anti-VEGF drugs, while no effective treatments are available for the dry form. Many observational studies, such as AREDS-1 and AREDS 2, have shown a potential role of micronutrient supplementation in lowering the risk of progression of the early stages of AMD. Recently, low-grade inflammation, sustained by dysbiosis and a leaky gut, has been shown to contribute to the development of AMD. Given the ascertained influence of the gut microbiota in systemic low-grade inflammation and its potential modulation by macro- and micro-nutrients, a potential role of diet in AMD has been proposed. This review discusses the role of the gut microbiota in the development of AMD. Using PubMed, Web of Science and Scopus, we searched for recent scientific evidence discussing the impact of dietary habits (high fat and high glucose or fructose diets), micronutrients (vitamins C, E, and D, zinc, beta-carotene, lutein and zeaxanthin) and omega-3 fatty acids on the modulation of the gut microbiota and their relationship with AMD risk and progression.
ARTICLE | doi:10.20944/preprints202007.0147.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: gut microbiota; obesity; weight-loss; Mediterranean diet; 16S rRNA; High-throughput sequencing
Online: 8 July 2020 (11:07:10 CEST)
Although it is known that the gut microbiota (GM) can be modulated by diet, the efficacy of specific dietary interventions in determining its composition and diversity in obese patients remains to be ascertained. The present work aims to evaluate the impact of a moderately hypocaloric Mediterranean diet on the GM of obese and overweight patients (OB). The GM of 23 OB patients (F/M= 20/3) was compared before (T0) and after 3 months (T3) of the nutritional intervention (NI). Fecal samples were analyzed by Illumina MiSeq sequencing of the 16S rRNA gene. At baseline, the GM characterization confirmed the typical obesity-associated dysbiosis. After 3 months of NI, patients presented a statistically significant reduction of the body weight and fat mass, along with changes in the relative abundance of many microbial patterns. In fact, we observed an increased abundance in several Bacteroidetes taxa (i.e. Sphingobacteriaceae, Sphingobacterium, Bacteroides spp., Prevotella stercorea) and depletion of many Firmicutes taxa (i.e. Lachnospiraceae members, Ruminococcaceae and Ruminococcus, Veillonellaceae, Catenibacterium, Megamonas). In addition, the phylum Proteobacteria showed an increased abundance, while the genus Sutterella, within the same phylum, decreased after the intervention. Metabolic pathways, predicted by bioinformatic analyses, showed a decrease in membrane transport and cell motility after NI. The present study extends our knowledge of the GM profiles in OB, highlighting the potential benefit of a moderate caloric restriction in counteracting the gut dysbiosis.
REVIEW | doi:10.20944/preprints202210.0362.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: gut microbiome; time-restricted feeding; intermittent fasting; targeted approach; hormonal signaling; metabolic regulators
Online: 24 October 2022 (12:00:48 CEST)
Each individual has a unique gut microbiota; therefore the genes in our microbiome outnumber the genes in our genome by about 150 to 1. Perturbation in host nutritional status influences gut microbiome composition and vice versa. The gut microbiome can help in producing vitamins, hormones, and other active metabolites that support the immune system; harvest energy from food; aid in digestion; protect against pathogens; improve gut transit and function; send signals to the brain and other organs, oscillating the circadian rhythm and coordinate with host metabolism through multiple cellular pathways. Gut microbiota can be influenced by host genetics, medications, diet, and lifestyle factors from preterm to aging. So before prescribing a customized treatment, it is crucial to monitor and count the gut flora as a focused biomarker. Many nutritional approaches that have been developed help in maintaining and restoring an optimal microbiome such as specific diet therapy, nutrition interventions and customized eating patterns. One of these approaches is time-restricted feeding/eating (TRF/E), a type of intermittent fasting (IF) in which a subject abstains from food intake for a specific time window. Such a dietary modification might alter and restore the gut microbiome for proper alignment of cellular and molecular pathways throughout the lifespan. In this review, we have highlighted that gut microbiota would be a targeted biomarker and TRF/E would be a targeted approach for restoring the gut microbiome associated molecular pathways like hormonal signaling, the circadian system, metabolic regulators, neural responses, and immune-inflammatory pathways. Consequently, modulation of gut microbiota through TRF/E could contribute in proper utilization and availability of the nutrients and in this way confer protection against diseases for harnessing personalized nutrition approaches to improve human health.
REVIEW | doi:10.20944/preprints202201.0320.v1
Subject: Life Sciences, Microbiology Keywords: Butyrate; Colorectal cancer; Gut microbiota; Diet; omega-3 PUFAs
Online: 21 January 2022 (11:33:23 CET)
Knowledge regarding the influence of the microbial community in cancer promotion or protection has expanded even more through the study of bacterial metabolic products and how they can modulate cancer risk, which represents an extremely challenging approach for the relationship between intestinal microbiota and colorectal cancer (CRC). This review discusses research pro-gresses in the effect of bacterial dysbiosis from a metabolic point of view, particularly on the bio-chemical mechanisms of butyrate, one of the main short chain fatty acids (SCFAs) with an-ti-inflammatory and anti-tumor properties in CRC. Increased daily intake of omega-3 polyun-saturated fatty acids (PUFAs) significantly increases the density of bacteria that are known to produce butyrate. Omega-3 PUFAs have been proposed as a treatment to prevent gut microbiota dysregulation and lower the risk or progression of CRC.
ARTICLE | doi:10.20944/preprints202109.0351.v1
Subject: Life Sciences, Microbiology Keywords: oral microbiota; gut microbiota; networks analysis; ecological niche; newborns
Online: 21 September 2021 (09:13:34 CEST)
The onset and progression of the salivary and gut microbiota, the transmission and the impact of the salivary microbiota on the development of early fecal microbial communities was herein explored. We characterized the microbiota of 82 faecal and 80 salivary samples, collected from 82 healty newborns at birth, 7, 15, 30, 90 and 180 days of life, by 16S rRNA targeted-metagenomics approach. Correlation heat-maps and co-occurrence networks were used to investigate microbial taxa relationship in saliva, gut and between the two ecosystems. In saliva microbiota, Streptococcus and Staphylococcus appeared as early commensals, dominating this ecosystem through the time, while Fusobacterium, Prevotella, Porphyromonas, Granulicatella and Veillonella were late colonizers. anaerobes as Enterobacteriace, Staphylococcus and Streptococcus, were gut microbiota pioneers, followed by the anaerobic Bifidobacterium, Veillonella, Eggerthella and Bacteroides. Streptococcus, Staphylococcus and Veillonella were shared by gut and saliva ecosystems (core microbiota). Early saliva and gut microbiota seem to evolve independently driven by local adaptation strategies, with the only exception for the oral Streptococcus and Veillonella genera, involved in gut microbiota development as seeding species. A more comprehensive knowledge of how oral microbiota may impact pathophysiological conditions of gut microbiota may open new avenues on the design of postbiotics.
REVIEW | doi:10.20944/preprints202103.0598.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Camellia sinensis; tea polyphenols; gut microbiota; gastrointestinal bacteria; systematic review
Online: 24 March 2021 (16:18:03 CET)
A diet high in polyphenols is associated with a diversified gut microbiome. Tea is the second most consumed beverage in the world, after water. The health benefits of tea might be attributed to the presence of polyphenol compounds such as catechins, theaflavins, tannins, and flavonoids. Although many studies are on tea, little is known of its effects on trillions of gut microbiota. Hence, this review is aimed at systematically studying the effect of tea polyphenols on the stimulation or suppression of gut microbiota in humans and animals. It was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Articles were retrieved from PubMed and Scopus databases, and data were extracted from 6 human trials and 15 animal studies. Overall, huge variations were observed in terms of microbiota composition between humans and animals. A more consistent pattern of diversified microbiota was observed in animal studies. Tea alleviated the gut microbiota imbalance caused by high-fat diet-induced obesity, diabetes, and ultraviolet-induced damage. Overall changes in microbiota composition measured by beta diversity analysis showed that tea had shifted the microbiota from the pattern seen in animals that received tea-free intervention. In humans, the prebiotic-like effect was observed towards gut microbiota, but these results appear in lower-quality studies. Beta diversity in human microbiota remains intact despite tea intervention; supplementation with different teas affected different types of bacterial taxa in the gut. These studies suggest that tea polyphenols may have a prebiotic effect in disease-induced animals and in a limited number of human interventions. Further intervention is needed to identify the mechanisms of action underlying the effects of tea on gut microbiota.
ARTICLE | doi:10.20944/preprints202010.0138.v1
Subject: Life Sciences, Other Keywords: Mass drug administration; Azithromycin; Gut microbiota; V4-16S rRNA sequencing
Online: 6 October 2020 (15:55:40 CEST)
Community-level mass treatment with azithromycin has been associated with a mortality benefit in children. However, antibiotic exposures result in disruption of the gut microbiota and repeated exposures may reduce recovery of the gut flora. We conducted a nested cohort study to examine associations between mass drug administration (MDA) with azithromycin and the gut microbiota of rural Malawian children aged between 1-59 months. Fecal samples were collected from the children prior to treatment and 6 months after two or four biannual rounds of azithromycin treatment. DNA was extracted from fecal samples and V4-16S rRNA sequencing used to characterize the gut microbiota. Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria were the dominant phyla while Faecalibacterium and Bifidobacterium were the most prevalent genera. There were no associations between azithromycin treatment and changes in alpha diversity, however, four biannual rounds of treatment were associated with increased abundance of Prevotella. The lack of significant changes in gut microbiota after four biannual treatments supports the use of mass azithromycin treatment to reduce mortality in children living in low- and middle-income settings.
ARTICLE | doi:10.20944/preprints201903.0005.v1
Subject: Life Sciences, Microbiology Keywords: oleic acid; acorn feed ham; gut microbiota; ulcerative colitis
Online: 1 March 2019 (08:42:26 CET)
Background: Diets based on meat products are not recommended in the case of ulcerative colitis (UC). However, some foods, as those containing high oleic acid and a low omega-6/omega-3 ratio show anti-inflammatory properties. The objective here is to test if some traditional cured meat products, as acorn-fed ham (high levels of oleic acid), may be useful for controlling inflammatory diseases as UC in animal models. Methods: 3 rat cohorts have been used: vegetable rat feed, control ham and acorn-fed ham (a traditional ham where high oleic acid concentration from acorns is storage in the muscle fat). UC was induced with DSS in drinking water ad libitum for one week. Short-chain fatty acids (SCFAs) and 16S rRNA from bacterial populations were analyzed in cecum samples. Colon samples were analyzed for histological parameters (inflammatory cell density, mucosa damages, myeloperoxidase). Results: In the acorn-fed ham cohort, a protective effect was observed with respect to UC disease activity index, inflammatory cells density, colon mucosa alterations, myeloperoxidase levels, blood total antioxidant capacity and lower levels of pro-inflammatory cytokines, in comparison with feed cohort. Both ham diets caused a reduction in Firmicutes and an increase in Actinobacteria, Bacteroidetes and Proteobacteria in comparison with rat feed diet. Also, acorn-fed ham diet induced changes in gut microbiota composition, with pronounced enrichments in anti-inflammatory bacterial genera such as Alistipes, Bacteroides, Blautia, Butyricimonas and Parabacteroides. Conclusions: In the acorn-fed ham cohort, as a result of the dietary intake of oleic acid and low intake of omega-6 fatty acids, a strong preventive effect against UC symptoms was observed, indicating a valuable effect of this traditional Mediterranean cured meat product.
ARTICLE | doi:10.20944/preprints201805.0375.v1
Subject: Behavioral Sciences, Other Keywords: autism phenome; gut microbiome; behaviour reversal; meta-analysis; 16srRNA sequencing; operational taxonomic units (OTUs)
Online: 25 May 2018 (16:15:27 CEST)
Background: Gut-Brain-Axis provides bidirectional communicational route; imbalance of which can have pathophysiological consequences. It is a frontier in autism research, affects 85% of autistic children (NIH report). Their microbiome has few overall microbes and smaller number of health promising microbes than their neurotypical peers. We hypothesize autism gut might play a role in manifestation of autism behaviours and on treatment, can revert back to normal behaviour considerably. The aim is to better understand to what degree gut microbiota of autism subjects differs from controls and identify bacterial species present exclusively in autism. Materials and Methods: 16s-rRNA-sequence of autism-subjects were retrieved from the American Gut Project Archive. Taxonomic assignment was inferred by similarity based methods using Quantitative Insights Into Microbial Ecology (QIIME). Species abundance was characterized and co-occurrence network was built to infer species interaction using measures of diversity. Statistical parameters were considered to validate the findings. Result: A total of 206 (1.8%) of American Gut Project datasets onstituted of autistic samples. Various bacteria such as Akkermansia sp., and Prevotella sp., were harboured in higher abundance in autistic children with statistical significance than in controls. Conclusion: These findings indicate connecting-link between gut-microbiome-brain-axis and autistic behaviour which can result in improved management
ARTICLE | doi:10.20944/preprints202002.0109.v1
Subject: Biology, Animal Sciences & Zoology Keywords: dietary fiber; SCFA; growth period; chickens; gut microbiota; microbiotal diversity; age; cecum
Online: 9 February 2020 (16:24:29 CET)
Increasing numbers of researchers are interested in the importance of dietary fiber for the gut microbiota, microbiotal metabolite SCFA, energy metabolism and gut health of the host. However, studies have demonstrated that long-term and longitudinal observation may be needed to evaluate the effect of dietary fiber better, and few such works have been made in chickens. Therefore, we successively fed low-fiber, high--fiber and low-fiber diets to two breeds of chickens during different growth periods (1—8, 9—20 and 21—50 weeks), aiming to longitudinally observe the long-term effect of altered dietary fiber on the gut microbiota, SCFA and development of cecum of chickens with age. The results showed that the composition and function of the gut microbiota, SCFA and the development of the cecum were different during different periods, which was largly affected by dietary fiber. However, the causes of some effects were different during the different periods. For example, compared with that in low-fiber chickens at 8 weeks, dominant fiber-degradation bacteria such as Bacteroidetes, Alloprevotella and SCFA-producing bacteria such as Faecalibacterium increased due to a high-fiber diet at 20 weeks, while due to a high feed intake in 50 weeks. Moreover, the concentration of SCFA in 20 weeks was significantly higher than in 8 weeks and 50 weeks, but the causes of this difference were also distinct. It was proposed that a long-term observation was needed to evaluate the effect of dietary fiber better on chickens. The metabolite pathways of ATP-binding cassette (ABC) transporters encoded by Firmicutes were enriched in 8 weeks, while a two-component system and β–glucosidase encoded by Bacteroidetes were enriched in 20 and 50 weeks. The trend was the same in two breeds of chickens except for Alloprevotella. In addition, the total content of SCFA in the contents of cecum was also affected by the size of the cecum. Surprisingly, the length of the cecum shortened from 20—50 weeks, maybe due to reduced dietary fiber.
ARTICLE | doi:10.20944/preprints202012.0416.v1
Subject: Medicine & Pharmacology, Allergology Keywords: dysbiosis; familial adenomatous polyposis,; ulcerative colitis; 16S rRNA; gut microbiota; geo-graphic populations
Online: 16 December 2020 (18:05:43 CET)
Inflammatory bowel diseases, familial adenomatous polyposis (FAP) and colorectal cancer (CRC) are associated with alterations of the intestinal microbiota. However, few data are available on the perpetuation of FAP and ulcerative colitis (UC) in relation to microbial dysbiosis. This study evaluated the UC and genetically confirmed FAP patients’ gut microbial balance in concordance to clinical outcome. Fecal materials (average mass of 0.54 g) were collected from three FAP and five UC patients to compare with healthy individuals as control group. Genomic materials of micro-biota were isolated for next generation sequencing of 16S rRNA that was performed by using QIAseq 16S/ITS panel in Illumina Miseq Platform. Data processing and bioinformatics analysis were performed via CLC Genomic Workbench bioinformatics tool. The comparison between FAP, UC and control group revealed an alteration in the intestinal microbial composition. More in details, relative abundance of class levels showed statistical significance differences among FAP, UC and control groups. Our preliminary data focused on the explanation of how dysbiosis can lead to inflammation and drive processes together with host genetic profile that leads to colorectal carcinogenesis.
Subject: Medicine & Pharmacology, Allergology Keywords: Cordyceps militaris; crude polysaccharides; selenium-rich crude polysaccharides; high-fat diet (HFD); obesity; dyslipidemia; hypertriglyceridemia; gut microbiota
Online: 3 December 2020 (10:26:45 CET)
Administration of crude polysaccharides extract from natural product is a promising gut microbiota-targeted approach to preventing obesity and associated metabolic disorders. Dietary restrictions can change the type and number of gut bacteria, which is an important factor in delaying the onset and burden of diseases. This study aimed to investigate the effects of high-yield crude polysaccharides from Cordyceps militaris (CMP) on high-fat diet (HFD) mice model and the gut microbiota community assembly, and to identify whether selenium (Se) addition would improve CMP action mode during cultivation. We found that the CMP treatment ameliorated adipose and liver pathologic morphology and fat accumulation in obese mice, while, SeCMP intervention was not superior than CMP in body mass gain, but notably decreasing serum triglyceride level increased by HFD. The upregulated expression of gene Cyp7a1 in liver and protein UCP1 in brown adipose tissue (BAT) preliminary indicated that the effect might relate to bile acids (BAs) metabolism pathway and thermogenesis. In addition, CMP showed a drastic decrease in the gut microbes which positively correlated with dyslipidemia parameters. Our result reveals the potential of CMP to be used as functional food in the prevention of diet-induced adipose and liver steatosis, so does SeCMP has outstanding capacity of improving dyslipidemia.
ARTICLE | doi:10.20944/preprints202209.0488.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: carrot juice; human gut microbiota; fermentation; prebiotic; lactate; Lactobacillus fermentum; Lactobacillus salivarius; Lactobacillus mucosae; Bacteroides uniformis; Enterococcus faecium
Online: 30 September 2022 (11:19:07 CEST)
Carrot juice and its associated beverage products are well-known healthy drinks all over the world. However, what effect carrot juice has on the human gut microbiota and how it is fermented by the intestinal microbes have not been studied. Here, using an in vitro model of anaerobic fermentation, we demonstrated that carrot juice could be fermented into lactate and acetate by the human gut microbiota. 16S high-throughput sequencing and bioinformatic analyses indicated that fermentation of carrot juice could significantly change the composition of the human gut microbiome. Interestingly, carrot juice remarkably increased the abundances of beneficial bacteria, including Lactobacillus fermentum, Lactobacillus salivarius, Lactobacillus mucosae and Bacteroides uniformis and decreased the population of opportunistic pathogenic bacteria, such as Enterococcus faecium in the gut. Collectively, our study illustrates a favorable effect of carrot juice on the human gut microbiota and lays a foundation for the development of carrot juice as a novel prebiotic agent.
Subject: Life Sciences, Biochemistry Keywords: Gut-Brain Axis; Nutrition; Microbiome; SCFA; Gut dysbiosis
Online: 13 May 2021 (13:30:00 CEST)
Diet plays a pivotal role in the overall health of an individual. Not only does it help carry out and regulate certain physiological functions, but it also can determine the composition of the gut microbiome. While the relative number of microorganisms that make up the gut microbiome vary between individuals and can be dependent on different environmental factors, there is evidence to suggest that composition of the microbiome can correlate with overall health or disease. When the GI microbiome is disturbed or suddenly changes it results in microbiome dysbiosis, a condition that correlates with the presence of certain diseases. Diseases linked to microbiome dysbiosis range from metabolic disorders, inflammatory bowel diseases to disorders of the brain. Many of these diseases are linked to the connection between the brain and the gut, known as the brain-gut axis. This bidirectional communication is important to maintain normal intestinal function, but is also responsible for the GI response to emotions as well as the emotional response to GI disturbances. By exploiting the interaction between microbiome health and nutrition, diet can be used to alleviate disease symptoms, protect against the development of certain conditions, and better maintain overall health. This review will examine the effects of nutrition on the microbiome, diseases linked to disruption of the normal microbiome, and the way that altering the diet can mitigate symptoms or prevent disease.
REVIEW | doi:10.20944/preprints202012.0041.v1
Subject: Medicine & Pharmacology, Allergology Keywords: liver cirrhosis; liver fibrosis; gut microbiome' gut-liver axis
Online: 1 December 2020 (18:19:00 CET)
Liver cirrhosis is one of the most prevalent chronic liver diseases worldwide. In addition to viral hepatitis, genetic conditions such as steatohepatitis, autoimmune hepatitis, sclerosing cholangitis, and Wilson’s disease can also lead to cirrhosis. Moreover, alcohol can cause cirrhosis on its own and exacerbate chronic liver disease from other causes. The treatment of cirrhosis can be divided into addressing the cause of cirrhosis and reversing liver fibrosis. To this date, there is still no clear consensus on the treatment of cirrhosis. Recently, there has been a lot of interest in potential treatments that modulate the gut microbiota and gut-liver axis for the treatment of cirrhosis. According to recent studies, modulation of the gut microbiome by probiotics ameliorates the progression of liver disease. The precise mechanism for relieving cirrhosis via gut microbial modulation has not been identified. This paper summarizes the role and effects of the gut microbiome in cirrhosis based on experimental and clinical studies on absorbable antibiotics, probiotics, prebiotics, and synbiotics. Moreover, it provides evidence of a relationship between the gut microbiome and liver cirrhosis.
REVIEW | doi:10.20944/preprints201804.0370.v1
Subject: Life Sciences, Microbiology Keywords: Parkinson’s disease; gut microbiome; neurodegenerative diseases; microbiota-gut-brain-axis
Online: 28 April 2018 (12:09:20 CEST)
In the last years evidence has emerged that neurodegenerative diseases (NDs) are strongly associated with the microbiome composition in the gut. Parkinson’s disease (PD) is the most intensively studied neurodegenerative disease in this context. In this review, we performed a systematic evaluation of published literature comparing changes in colonic microbiome in PD to the ones observed in other NDs including Alzheimer’s Disease (AD), Multiple system atrophy (MSA), Multiple sclerosis (MS), Neuromyelitis optica (NMO) and Amyotrophic lateral sclerosis (ALS). To warrant comparability of different studies, only human case-control studies were included. Several studies showed an increase of Lactobacillus, Bifidobacterium, Verrucomicrobiaceae and Akkermansia in PD. A decrease in PD was observed of Faecalibacterium spp., Coprococcus spp., Blautia spp., Prevotella spp. and Prevotellaceae. On low taxonomic resolution, like phylum level, the changes are not disease specific and inconsistent. However, on higher taxonomic resolution like genus or species level, a minor overlap was observed between PD and MSA, both alpha synucleinopathies. We show that a methodical standardization of sample collection and analysis is necessary for ensuring the reproducibility and comparability of data. We also provide the evidence, that assessing the microbiota composition at high taxonomic resolution, reveals changes in relative abundance, that may be specific or characteristic for one disease, or a disease-group and might evolve discriminative power. The interactions between bacterial species and strains and moreover the co-abundances must be more deeply investigated before assumptions of the effects of specific bacteria on the host can be made with certainty.
REVIEW | doi:10.20944/preprints202003.0293.v1
Online: 19 March 2020 (02:23:21 CET)
Recently scientific research began to shift their focus on looking at both the gut and the skin microbiota as having a reciprocal and integral relationship with one another, rather than assessing them as separate and unrelated fields. In the past five years, the field of microbial endocrinology emerged, which examines how our gut microbiota influences and modulates hormones. We’ve known for decades that hormones greatly affect the condition of the skin, and many skin conditions are often treated with oral hormonal therapy as means to internally treat skin conditions visible on the dermis. Now, a growing body research and discourse examining this triad of biological spheres – gut microbiota, skin microbiota, and the endocrine system – as interconnected rather than binary and unrelated. While there is ample research established and being conducted examining the gut-skin axis, the gut-brain axis, and the gut-hormone axis, through this paper I will review and synthesize some of the significant advancements in this emerging and inclusive field of science to suggest that the fields need to expand the axis and their modality for researching these fields as a connected whole in order to better understand the role of the microbiota in disease prevention as a whole.
REVIEW | doi:10.20944/preprints201807.0526.v1
Subject: Medicine & Pharmacology, Psychiatry & Mental Health Studies Keywords: psychiatry; gut microbiome; probiotics
Online: 27 July 2018 (03:22:02 CEST)
The microbiome gut brain (MGB) axis involves bidirectional routes of communication and has emerged as a potential therapeutic target for multiple medical specialities including psychiatry. Significant numbers of preclinical trials have taken place with some transitioning to clinical studies in more recent years. Some positive results have been reported secondary to probiotic administration in both healthy populations and specific patient groups. This review aims to summarise the current understanding of the MGB axis and the preclinical and clinical findings relevant to psychiatry. The link between the gut microbiome and irritable bowel syndrome (IBS) is well established. Significant differences have been identified between the microbiome of patients with a diagnosis of depressive disorder and healthy controls. Similar findings have occurred in patients diagnosed with bipolar affective disorder. A probiotic containing Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium bifidum produced clinically measurable symptom improvement in patients with depressive disorder. To date some promising results have suggested that probiotics could play a role in the treatment of stress-related psychiatric disease. However, more well-controlled clinical trials are required to determine which clinical conditions are likely to benefit most significantly from this novel approach.
ARTICLE | doi:10.20944/preprints202201.0032.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: antibiotic consumption; gut flora; dysbiosis; Alzheimer disease; dementia; gut-brain axis, mediator molecules
Online: 5 January 2022 (10:44:59 CET)
Background and objectives: Alzheimer's disease (AD) is a progressive neurodegenerative illness, responsible for 60-70% of all dementias, affecting over 50 million people worldwide, and nearly 11 million in European countries. Several putative factors are identified in the literature as causative agents or risk factors for the development of AD. The amyloid cascade hypothesis has been the main hypothesis about the pathophysiology of AD for decades. Recent studies raised the possible role of dysbiosis in the development of AD which prevents memory loss. The amyloid-β (Aβ) deposition might be considered as an inflammatory reaction to certain molecular products arising from the altered microbiome. Based on the above observations, it has been suspected, that antibiotic consumption patterns of different antibiotic classes might be associated with the prevalence of AD in European countries. Methods: Antibiotic consumption (ECDC) for 1997-2007, 2008-2018, and as the whole 1997-2018 period, have been compared to the AD prevalence for 2018 expressed in percentage of the population and statistically analyzed by Pearson calculation. Results: A significant positive correlation has been found between the AD prevalence (2018) and the average quinolone consumption for the year 1997-2007 (p: 0.044). A similar association was not observed for the entire 22 years (1997-2018) of the average quinolone consumption, and the years 2008-18, indicating 10-20 years of time-lapse between the antibiotic exposure and the development of AD. The ratio of broad-spectrum and narrow-spectrum antibiotics (B/N) estimated in the ECDC database for the years of 2008-2018 showed a strong positive association with AD prevalence (2018) (p: 0.026) and a positive correlation tendency for the entire 22 years 1997-2018 (p: 0.063), but none for the years 1997-2007 (p: 0.241). Broad-spectrum, beta-lactamase sensitive penicillin (J01CA) consumption showed a positive (non-significant) correlation with the prevalence of AD for the years 2008-2018 (p:0.080).Discussion: Our study indicated the possible sequential role of certain classes of antibiotics in the development of dysbiosis leading to amyloid deposits of AD, which strengthen the possible role of different mediator molecules (short-chain fatty acids, lipopolysaccharides, etc.) produced by the altered microbiome in the development of AD.
REVIEW | doi:10.20944/preprints202104.0175.v1
Subject: Life Sciences, Biochemistry Keywords: Gut microbiome; Western and indigenous/traditional cultures; gut health; disease; lifestyle; novel microbials
Online: 6 April 2021 (12:40:04 CEST)
The mammalian gut ecosystem plays critical roles in multiple functions related to health and homeostasis. In many cases, disturbances in the gut ecosystem are associated with a large number of metabolic and chronic diseases and disorders such as diabetes, cancer, and obesity. A diverse community of microorganisms ranging from viruses to bacteria comprise the gut microbiota, which is often considered as an organ in itself. Recent studies have profiled the influence of lifestyles and dietary behavior by comparing the gut microbiome of populations with different cultural underpinnings. In this review, we provide an overview of the studies which report the influence on the gut microbial composition of dietary and lifestyle patterns in different contexts such as western industrialized countries and indigenous cultures (corresponding to different lifestyle gradients such as hunter-gatherers and pastoralists) and how this association may influence health and disease.
ARTICLE | doi:10.20944/preprints202202.0350.v1
Online: 28 February 2022 (08:53:11 CET)
Bifidobacterium are a beneficial and dominant member of the breast-fed infant gut microbiome. However, the health benefits of Bifidobacterium are partially species dependent. Here we characterize the species and subspecies of Bifidobacterium present in breastfed infants around the world. Across populations, three distinct patterns of Bifidobacterium colonization emerged: 1) Dominance of Bifidobacterium longum subspecies infantis, 2) Prevalent Bifidobacterium of multiple species, and 3) Frequent absence of Bifidobacterium. These patterns appear related to country history of breastfeeding, with infants in countries with historically high rates of long duration breastfeeding more likely to be colonized by B. longum subspecies infantis compared with infants in countries with histories of shorter duration breastfeeding. These findings highlight the need to consider historical and cultural influences on gut commensal survival influence present day colonization patterns in order to understand epidemiological transmission patterns of Bifidobacterium and other major gut commensals.
ARTICLE | doi:10.3390/sci1030065
Online: 16 December 2019 (00:00:00 CET)
Toll-like receptor 5 ligand, flagellin, and Vascular Adhesion Protein-1 (VAP-1) are involved in non-alcoholic fatty liver disease (NAFLD). This study aimed to determine whether VAP-1 mediates flagellin-induced hepatic fat accumulation. The effects of flagellin on adipocyte VAP-1 expression were first studied in vitro. Then, flagellin (100 ng/mouse) or saline was intraperitoneally injected to C57BL/6J WT and C57BL/6-Aoc3-/- (VAP-1 KO) mice on high-fat diet twice a week every two weeks for 10-weeks. After that, the effects on inflammation, insulin signaling, and metabolism were studied in liver and adipose tissues. Hepatic fat was quantified histologically and biochemically. Because flagellin challenge increased VAP-1 expression in human adipocytes, we used VAP-1 KO mice to determine whether VAP-1 regulates the inflammatory and metabolic effects of flagellin in vivo. In mice, VAP-1 mediated flagellin-induced inflammation, leukocyte infiltration and lipolysis in visceral adipose tissue. Consequently, increased release of glycerol led to hepatic steatosis in WT but not KO mice. Flagellin-induced hepatic fibrosis was not mediated by VAP-1. VAP-1 KO mice harbored more inflammation-related microbes than WT, while flagellin did not affect the gut microbiota. Our results suggest that by acting on visceral adipose tissue, flagellin increased leukocyte infiltration that induced lipolysis. Further, the released glycerol participated in hepatic fat accumulation. In conclusion, the results describe that gut microbial flagellin through VAP-1 induced hepatic steatosis.
ARTICLE | doi:10.20944/preprints202209.0254.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: alcohol use disorder; gut-dysfunction; gut-thyroid axis; pro-inflammatory cytokines; thyroid-associated hormones
Online: 19 September 2022 (03:09:51 CEST)
(1) Background: Heavy and chronic alcohol intake causes altered gut-permeability and dysfunction; and exhibits a unique pro-inflammatory state. Thyroid-associated hormones and proteins may be dysregulated by alcohol administration; however, the impact of altered gut-derived changes on thyroid function is unclear. This study investigated the role of gut-dysfunction and pro-inflammatory activity on thyroid function in patients with alcohol use disorder (AUD). (2) Methods: Male and female AUD patients (n=44) were grouped as Gr.1 with normal thyroid stimulating hormone (TSH) levels (n=28, 0.8≤TSH≤3 mIU/L); and Gr.2 with clinically elevated TSH levels (n=16, TSH> 3 mIU/l). Demographics, drinking measures, comprehensive metabolic panel, and candidate thyroid markers (TSH, circulating triiodothyronine [T3] and free thyroxine [fT4]) were tested. Plasma-derived gut-dysfunction associated markers (lipopolysaccharide [LPS], LPS-binding protein [LBP], and LPS-induced pathogen-associated protein [CD14]), and cytokine profile (IL1-β, TNF-α, IL-6, IL-8, MCP-1, PAI-1) were analyzed and compared with the thyroid, demographic, and drinking markers. (3) Results: Both groups presented with a borderline overweight category of BMI. Gr.2 presented with numerically higher level of chronic and heavy drinking patterns vs Gr.1. fT4 levels were elevated while T3 was within normal limits in both the groups. Gut-dysfunction markers LBP and CD14 were numerically elevated in Gr.2 vs Gr.1 suggesting subtle ongoing changes; however, the difference was not statistically significant. All pro-inflammatory cytokines were significantly elevated in Gr.2 among IL1-, MCP-1, and PAI-1. Gr.2 showed a strong and statistically significant effect of gut-immune-pituitary response (r=0.896, p=0.002) on TSH levels in a multivariate regression model with LBP, CD14, and PAI-1 levels as upstream variables; this assessment was not significant in Gr.1. In addition, AUROC analysis demonstrated that many of the cytokines strongly predicted TSH in Gr.2, including IL-6 (area=0.774, p<0.001) and TNF- (area=0.708, p=0.017) among others. This was not observed in Gr.1. Gr.2 demonstrated elevated fT4 as well as TSH, which suggests that there was subclinical thyroiditis with underlying CNS dysfunction and lack of a negative feedback loop. (4) Conclusions: These findings reveal the toxic effects of heavy and chronic drinking that play a pathological role in thyroid gland dysregulation employing the gut-brain axis. These results also strongly emphasize potential directions to strongly consider thyroid dysregulation in the overall medical management of AUD.
REVIEW | doi:10.20944/preprints202111.0175.v1
Subject: Biology, Other Keywords: atherosclerotic cardiovascular disease (ACVD); atherosclerosis; gut dysbiosis; immune system; gut microbial metabolites; SCFAs; TMAO
Online: 9 November 2021 (13:45:20 CET)
Atherosclerosis is a leading cause of cardiovascular disease and mortality worldwide. Alterations in the gut microbiota composition, known as gut dysbiosis, have been shown to contribute to atherosclerotic cardiovascular disease (ACVD) development through several pathways. Disruptions in gut homeostasis are associated with activation of immune processes and systemic inflammation. The gut microbiota produces several metabolic products, namely trimethylamine (TMA), which is used to produce the proatherogenic metabolite trimethylamine-N-oxide (TMAO). Short chain fatty acids (SCFAs), including acetate, butyrate, and propionate, and certain bile acids (BAs) produced by the gut microbiota lead to inflammation resolution and decrease atherogenesis. Chronic low-grade inflammation is associated to common risk factors for atherosclerosis, including metabolic syndrome, type 2 diabetes mellitus (T2DM), and obesity. Novel strategies for reducing ACVD include the use of nutraceuticals such as resveratrol, modification of glucagon-like peptide 1 (GLP-1) levels, supplementation with probiotics, and administration of prebiotic SCFAs and BAs. Investigation into the relationship between the gut microbiota and its metabolites, and the host immune system could reveal promising insight into ACVD development, prognostic factors, and treatments.
ARTICLE | doi:10.20944/preprints202211.0443.v1
Online: 23 November 2022 (09:46:44 CET)
Polyurethane (PU) is a polymer widely used by humans whose recycling is highly complex due his chemical structure, being limited to incineration or accumulation in landfills. Biodegradation by enzymes and microorganisms has been studied for decades as an effective method of biological decomposition. In this study, Tenebrio molitor larvae (T. molitor) were fed with polyurethane foams, which gut enzymes and microorganisms were capable of degrading the polymer by 35% in 17 days of treatment, producing a weight loss of 14% in the mealworm. Changes in T. molitor gut bacterial community and diversity were observed, which may be due to colonization of species associated with PU degradation. Physical and structural biodegradation in PU by T. molitor compared to virgin PU, was demonstrated by Fourier Transform InfraRed spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA) and Scanning Electron Microphotography (SEM).
REVIEW | doi:10.20944/preprints202207.0374.v1
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: probiotic; stroke; gut microbiome; meta-analysis
Online: 25 July 2022 (11:37:22 CEST)
Background: Pharmacologic and non-pharmacologic treatments for stroke are essential but could be costly or harmful whereas probiotic has been a promising alternative. This scoping review aimed to synthesize the in vitro and in vivo evidence of probiotics on stroke-related neurological, biochemical, and histochemical outcomes. Method: We searched in PubMed, Embase, and Cochrane Central Register of Clinical up to May 7, 2021, and screened by two independent reviewers. We included the use of probiotics, prebiotics, and symbiotics both in vitro and in vivo for the prevention or treatment of the stroke-related model. Result: Of 6,293 articles, 4,990 passed the initial screen, of which 36 theme-related full-texts were assessed and 13 were included in this review. Probiotics could ameliorate the neurological deficit and show their property as an anti-inflammation and anti-oxidative stress. Histopathologically decreased loss of cerebral volume and inhibition of neuronal apoptosis were found. Conclusion: There are potential cognitive benefits of probiotic supplementation, especially among animal models, on decreasing cerebral volume, increasing neurological score, and decreasing the inflammatory response. However, further investigation is needed to validate these conclusions in various populations.
ARTICLE | doi:10.20944/preprints202107.0560.v1
Subject: Life Sciences, Biochemistry Keywords: diversity index; multifractal; metagenome; gut mtagenome
Online: 26 July 2021 (10:04:41 CEST)
Species diversity in microbiome is a cutting-edge concept in metagenomic research. In this study, we propose a multifractal analysis for metagenomic research. From the chaos game representation (CGR) visualization of simulated and real metagenomes, we find that there exists self-similarity in the visualization of metagenomes. Then we compute the multifractal dimensions for simulated and real metagenomes. For simulated metagenomes, we also compute their diversity indices, such as species richness indices, Shannon’s diversity indices and Simpson’s diversity indices respectively for varying value of . Fom the Pearson correlation coefficients between their multifractal dimensions and traditional species diversity indices, we find that the correlation coefficients between the multifractal dimensions and species richness indices and Shannon diversity indices reach their maximums at respectively. The correlation coefficients between the multifractal dimensions and Simpson’s diversity indices reach their maximums at nearly. So the traditional diversity indices can be unified by the frame of multifractal analysis. These results coincided with the similar results in macrobial ecology. Finally, we apply our methods to real metagenomes of 100 infants’ gut microbiomes when they are newborn, 4 months and 12 months. Our results show that multifractal dimensions of infants’ gut microbiomes can discriminate the age difference.
ARTICLE | doi:10.20944/preprints202101.0455.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Knee Osteoarthritis; Vitamin D; gut microbiome
Online: 22 January 2021 (14:29:58 CET)
Background: A Few preclinical studies have shown that Knee osteoarthritis (KOA) is linked to gut microbiome dysbiosis and chronic inflammation. This pilot study was designed to look at the gut microbiome composition in KOA patients and normal individuals with or without vitamin D deficiency (VDD, serum vitamin D <30 ng/ml). Methods: This pilot study was conducted prospectively in 24 participants. The faecal samples of all the participants were taken for DNA extraction. The V3-V4 region of 16s rRNA was amplified and the library was prepared and sequenced on the Illumina Miseq platform. Results: The mean (±SD) age was 45.5 (±10.2) years with no defined co-morbidities. Of 447 total Operational Taxonomic Units (OTUs), a differential abundance of 16 nominally significant OTUs between the groups were observed. Linear discriminate analysis (LEfSe) revealed a significant difference in bacteria among the study groups. Pseudobutyrivibrio and Odoribacter were specific for VDD while Parabacteroides, Butyricimonas, and Gordonibacter were abundant in the KOA_VDD group and Peptococcus, Intestimonas, Delftia, and Oribacterium were abundant in the KOA group. About 80% of bacterial species were common among different groups and hence labeled as core bacterial species. However, the core microbiome of KOA and VDD groups were not seen in the KOA_VDD group, suggesting that these bacterial groups were affected by the interaction of the KOA and VDD factors. Conclusion: Parabacteroides, Butyricimonas, Pseudobutyrivibrio, Odoribacter, and Gordonibacter are the predominant bacteria in vitamin D deficient patients with or without KOA. Together these results indicate an association between the gut microbiome, vitamin D, and knee osteoarthritis.
REVIEW | doi:10.20944/preprints202005.0037.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: FFAR2; FFAR3; microbiota; gut; immune; SCFA
Online: 3 May 2020 (08:32:51 CEST)
Abstract: Role of gut microbiome in human health is becoming apparent. The major functional impact of gut microbiome is transmitted through the microbial metabolites that are produced in the gut and interact with host cells either in the local gut environment or get absorbed in the circulation to impact distant cells/organs. Short chain fatty acids (SCFAs) are the major microbial metabolites that are produced in the gut through fermentation of non-digestible fibers. SCFAs are known to function through various mechanism, however, their signaling through free-fatty acid receptor 2 and 3 (FFAR2/3; type of G-coupled protein receptors) is new therapeutic approach. FFAR2/3 are widely expression in diverse cell types in human and mice, and functions as sensors of SCFAs to change several physiological and cellular functions. FFAR2/3 modulates neurological signaling, energy metabolism, intestinal cellular homeostasis, immune response and hormone synthesis. FFAR2/3 functions through Gi and/or Gq signaling, that is mediated through specific structural features of SCFAs-FFAR2/3 bindings and modulating specific signaling pathway. In this review, we discussed the wide-spread expression and structural homologies between human and mice FFAR2/3, and their role in different human health conditions. This information can unlock opportunities to weigh the potential of FFAR2/3 as drug target to prevent human diseases.
REVIEW | doi:10.20944/preprints201807.0434.v1
Online: 23 July 2018 (21:33:29 CEST)
The tissue micro environment or milieu consists of a highly dynamic population of cellular and non-cellular components which constitute a complex regulatory network aimed at maintaining the organ homeostasis. In the modern medicine the discovery of miRNAs is undoubtedly a promising field of research and they are essential in orchestrating immune system logic and their release in the gut micro milieu can directly affect bacterial gene expression. Here, we brieﬂy review the role of microRNAs, focuses on their role on immune system components in physiological and pathophysiological gut micro milieu.
ARTICLE | doi:10.20944/preprints201912.0239.v1
Subject: Keywords: OptiCell; microbial diversity; gut microbiota; gut health; free-range chickens; caged chickens; SCFA; mucus layer; welfare
Online: 18 December 2019 (05:25:45 CET)
It is of merit to study the appropriate amount of fiber to add to free-range chickens feed to improve the microbial diversity and gut health in times of plant fiber deprivation. OptiCell is a useful source of fiber as a type of eubiotic lignocellulose, and its positive effects on the growth performance and laying performance of chickens has already been proven. However, few researchers have researched the effects of adding OptiCell on the gut microbiota of chickens. In this research we added three different levels of OptiCell (0%, 2% and 4%) to the feed of caged and free-range Bian chickens from September to November, aiming to observe the effects of adding OptiCell and different feeding modes on the gut microbial diversity and gut health of chickens, and aiming to determine an appropriate amount of OptiCell. The results showed that adding OptiCell could increase the thickness of the cecum mucus layer and the abundance of Akkermansia and Faecalibacterium in caged chickens, and 4% OptiCell was optimum. In addition, adding OptiCell increased the microbial diversity and the abundance of the butyrate-producing bacteria Faecalibacterium and Roseburia of fee-range chickens. The α-diversity and the length of the small intestine with 2% OptiCell in free-range chickens were better than with 2% OptiCell in caged chickens. In addition, compared with caged chickens, the free-range chickens had longer small intestine and lower GLP-1. Taken together, an appropriate amount of OptiCell benefitted the microbial diversity and health of chickens; it was necessary to add dietary fiber to the feed of free-range chickens when plant fibers was lacking, and 2% OptiCell was found to be optimum.
REVIEW | doi:10.20944/preprints201810.0554.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: gut brain axis; microbiota; functional gastrointestinal disorders
Online: 24 October 2018 (07:41:58 CEST)
The central nervous system (CNS) and the human gastrointestinal (GI) tract communicate through the gut-brain axis (GBA). Such communication is bi-directional and involves neuronal, endocrine and immunological mechanisms. The scientific data are mounting that gut microbiota is a source of a number of neuroactive and immunocompetent substances, which shape the structure and function of brain regions involved in control of emotions, physical activity and cognition. Most of GI maladies are associated with altered transmission within the GBA and influenced both by genetic and environmental factors. Current treatment protocols widely advocated for the treatment of GI disorders may positively or adversely affect the composition of intestinal microbiota with diverse impact on therapeutic outcome. The alterations of gut microbiota have been associated with mood and depressive disorders. and mental health is frequently altered in the course of many GI and non-GI ailments. Deregulation of the GBA may constitute a grip point for the development of diagnostic tools and personalized microbiota-based therapy. For example next generation sequencing (NGS) offers detailed analysis of microbiome footprints in patients with mental and GI disorders. Psychobiotics are new class of beneficial bacteria, with documented efficacy in the treatment of gut-brain axis disorders.
ARTICLE | doi:10.20944/preprints201707.0039.v1
Subject: Medicine & Pharmacology, Allergology Keywords: diet, gut microbiota, epigenetics, inflammatory bowel diseases
Online: 15 July 2017 (00:46:37 CEST)
Inflammatory bowel diseases (IBD) represent a growing public health concern due to increasing incidence worldwide. The current notion on the pathogenesis of IBD is that genetically susceptible individuals develop intolerance to dysregulated gut microflora (dysbiosis) and chronic inflammation develops as a result of environmental triggers. Among the environmental factors associated to IBD, diet plays an important role in modulating the gut microbiome, influencing epigenetic changes and, therefore, could be applied as a therapeutic tool to improve the disease course. Nevertheless, the current dietary recommendations for disease prevention and management are scarce and of weak evidence. This review summarizes the current knowledge on the complex interactions among diet, microbiome and epigenetics in IBD. Whereas over-abundance of calories and some macronutrients increases gut inflammation, several micronutrients have the potential to modulate it. Immunonutrition has emerged as a new concept putting forward the importance of vitamins such as vitamins A, C, E, D, folic acid and beta-carotene and trace elements such as zinc, selenium, manganese and iron. However, when assessed in clinical trials, specific micronutrients exerted a limited benefit. Beyond nutrients, anti-inflammatory dietary patterns as a complex intervention approach have become popular over the recent years. Hence, exclusive enteral nutrition in pediatric Crohn’s disease is the only nutritional intervention currently recommended as a first-line therapy. Other nutritional interventions or specific diets including the Specific Carbohydrate Diet, the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyol diet and most recently the Mediterranean diet have shown strong anti-inflammatory properties and provide a promise for improving disease symptoms. Definitely, more work is required to evaluate the role of individual food compounds and complex nutritional interventions with potential to decrease inflammation as means for prevention and management of IBD.
ARTICLE | doi:10.20944/preprints202202.0218.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: Illumina MiSeq sequencing; gut microflora; Lactobacilli; immunostimulant; anticancer
Online: 17 February 2022 (17:31:15 CET)
We demonstrated the role of natural probiotics 3L, 3 Lactobacilli, in the establishment of a strong and sustainable beneficial healthy gut flora, after chemotherapy through experimental results through in vivo model. Using rat CTX model (immunosuppression induced by cyclophosphamide), we suggested some new adjuvant to chemotherapy as drugs + lactobacillus treament. Further, we proposed a new probiotic formulation (L. acidophilus + L. casei + L. plantarum) to be explored in the prevention of health condition loss by alteration of the general immune system, in numerous studies that reported the use of probiotics involving Lactobacillus in the post-chemo or post-surgical procedures. Here, in our study, Illumina MiSeq sequencing was used to generate sequencing data from microbial genomic DNA libraries, which is appreciable to check for the effects of 3L on bacteria. Microbiome analysis, phylogenetic and classification reports, community data have supported the experiments and the results where 3L had strong beneficial effects on the microbiome. Further, the influence on specific metabolic pathways are assisted in deriving the conclusion of the study (use of 3L for cancer therapy) to the mode of action, mechanistically by correcting microbiota composition and enhancing specific gut metabolic functions.
REVIEW | doi:10.20944/preprints202109.0228.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: gut microbiota; critically ill; faecal microbial transplantation; multiorgan
Online: 14 September 2021 (09:52:56 CEST)
The human gut microbiota consists of bacteria, archaea, fungi, and viruses. It is a dynamic ecosystem shaped by several factors, which play an essential role in both healthy and diseased states of humans. A disturbance of the gut microbiota, also termed “dysbiosis,” is associated with increased host susceptibility to a range of diseases. Because of splanchnic ischaemia, exposure to antibiotics, and/or underlying the disease critically ill patients loose 90% of the commensal organisms in their gut within hours after the insult. This is followed by a rapid overgrowth of potentially pathogenic and pro-inflammatory bacteria altering metabolic, immune, and even neurocognitive functions and turning the gut into the driver of systemic inflammation and multiorgan failure. Indeed, restoring healthy microbiota by means of faecal microbiota transplantation (FMT) in the critically ill is an attractive and plausible concept in intensive care. Yet, available data from controlled studies are limited to probiotics and FMT for severe C. difficile infection or severe inflammatory bowel disease. Case series and observational trials generate hypothesis that FMT might be feasible and safe in immunocompromised patients, refractory sepsis, or severe antibiotic-associated diarrhea in ICU. There is a burning need to test these hypotheses in randomized controlled trials powered for determination of patient-centered outcomes.
REVIEW | doi:10.20944/preprints202105.0143.v1
Subject: Life Sciences, Biochemistry Keywords: Co-infection; Drug resistance; Gut microbiota; Salmonellosis; Schistosoma
Online: 7 May 2021 (12:02:03 CEST)
Antibiotic inefficacy in treating bacterial infections is largely studied in the context of developing resistance mechanisms. However, little attention has been paid to combined diseases mechanisms, interspecies pathogenesis and the resulting impact on antimicrobial treatment. This review will consider the co-infections of Salmonella and Schistosoma mansoni. It summarises the protective mechanisms that the pathophysiology of the two infections confer, which leads to an antibiotic protection phenomenon. This review will elucidate the functional characteristics of the gut microbiota in the context of these co-infections, the pathogenicity of these infections in infected mice, and the efficacy of the antibiotics used in treatment of these co-infections over time. Salmonella-Schistosoma interactions and the mechanism for antibiotic protection are not well established. However, antimicrobial drug inefficacy is an existing phenomenon in these co-infections. The treatment of schistosomiasis to ensure the efficacy of antibiotic therapy for bacterial infections should be considered in co-infected patients.
ARTICLE | doi:10.20944/preprints202009.0241.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: prebiotic; oligosaccharides; gut microbiota; fatty liver; metabolism; mitochondria
Online: 11 September 2020 (04:17:52 CEST)
Understanding the importance of gut microbiota (GM) in non-alcoholic fatty liver disease (NAFLD) has raised the hope for therapeutic microbes. We have shown that high hepatic fat associated with low abundance of Faecalibacterium prausnitzii in humans and further, administration of F. prausnitzii prevented NAFLD in mice. Here, we aimed to target F. prausnitzii by prebiotic xylo-oligosaccharides (XOS) to treat NAFLD. First, the effect of XOS on F. prausnitzii growth was assessed in vitro. Then, XOS was supplemented or not with high (HFD) or low (LFD) fat-diet for 12-weeks in Wistar rats (n=10/group). XOS increased F. prausnitzii growth having only minor impact on the GM composition. When supplemented with HFD, XOS prevented hepatic steatosis. The underlying mechanisms involved enhanced hepatic β-oxidation and mitochondrial respiration. 1H-NMR analysis of caecal metabolites showed that compared to HFD, LFD group had healthier caecal short-chain fatty acid profile and the combination of HFD and XOS was associated with reduced caecal isovalerate and tyrosine, metabolites previously linked to NAFLD. Caecal branched-chain fatty acids associated positively and butyrate negatively with hepatic triglycerides. In conclusion, our study identifies F. prausnitzii as a possible target to treat NAFLD with XOS. The underlying preventive mechanisms involved improved hepatic oxidative metabolism.
REVIEW | doi:10.20944/preprints202002.0396.v1
Subject: Medicine & Pharmacology, Behavioral Neuroscience Keywords: Alzheimer's disease; sirtuins; mitochondria; leaky gut; inflammation; neuroimmune
Online: 27 February 2020 (10:52:33 CET)
Alzheimer's disease (AD) has been the subject of extensive investigation as to its biological underpinnings. However, this has produced little of therapeutic benefit or indeed provided any accepted biomarkers that could tailor treatment. This chapter reviews data on the main pathophysiologic processes that have been widely shown to be altered in AD, including circadian dysregulation, mitochondrial dysfunction, gut dysbiosis, and immune-glia-platelet activation. It is proposed that alterations in the gut microbiome, including gut dysbiosis and increased gut permeability drive changes in mitochondrial function that are intimately associated with significant variations in sirtuin expression. Both mitochondria-located and nucleus/cytoplasm located sirtuins can act on mitochondrial function in different cells and body systems to co-ordinate the ageing-associated changes that underpin AD. The sirtuins are therefore key aspect to a developmental model of AD that is more 'holistic' in perspective, thereby providing a framework for the detection of earlier biomarkers and more successful treatment for the heterogenous nature of AD pathoetiology.
ARTICLE | doi:10.20944/preprints201909.0200.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: trilactic glyceride; intestinal function; gut microbiota; weaned piglet
Online: 18 September 2019 (07:28:51 CEST)
Both lactic acid and short chain fatty acid (SCFA) play important roles in maintenance of intestinal epithelial structure and function. Trilactic glyceride (TLG) obtains both excellences of lactic acid and SCFA. This study was to investigate the effects of trilactic glyceride on growth performance, blood parameters, liver function, intestinal morphology and intestine function of piglets. Twelve weaned piglets (21±2 d) were randomly allocated to two treatment groups: 1) control group, piglets fed the basal diet; 2) TLG group, piglets fed the basal diet supplemented with 0.5 % TLG. On day 21 of the trial, D-xylose (0.1 g/kg·BW) was orally administrated to all piglets and blood samples were collected 1 h thereafter. Then, all the piglets were sacrificed to examine intestinal mucosal morphology and collect fatty tissue, liver and intestinal mucosa for further analysis. The results showed that: compared with the control group, TLG group decreased blood ALB and GGT on day 10 and 20, TLG group decreased blood TP and increased blood TG on day 20 of the trail (p < 0.05); TLG group decreased blood D-xylose and LDL, increased blood HDL (p < 0.05). These data suggested that supplementing trilactic glyceride had beneficial impacts on promoting nutrients’ metabolism, maintaining intestinal integrity, and alleviating oxidative stress and diarrhoea. Further research of molecular mechanisms showed changing expression levels of related proteins and genes, suggesting that these could be involved in the regulation of the impact. The community composition of the gut microbiota was also found to be altered in several operational taxonomic units within the genus, Prevotella (order Bacteroidales), and the order, Clostridiales.
COMMUNICATION | doi:10.20944/preprints201908.0034.v1
Subject: Biology, Entomology Keywords: freshwater insects; gut microbiome; nitrogen provisioning; nitrate reduction
Online: 5 August 2019 (00:48:14 CEST)
Biological nitrogen (N) provisioning is a seminal function of the gut microbes in several terrestrial insects, given the unbalanced carbon (C) and N ratios of their diets. Although freshwater insects face comparable dietary N limitations like terrestrial insects, little is known about this function by their gut microbiomes. In this study, we investigated microbial nitrate reduction to ammonium pathways as possible routes of biological N provisioning in two freshwater insects; filter-feeding Hydropsychidae and grazers/collectors Baetidae. After incubation in filtered (microbe-free) artificial stream water (ASW) containing dissolved 15N-labeled nitrate (treatment) or standard nitrate (control), bulk δ15N values of treatment samples (Baetidae = 100.62 ± 10.23, mean ± S.E.; Hydropsychidae = 76.82 ± 7.20) were significantly higher than controls (Baetidae = 10.14 ± 0.12 ; Hydropsychidae = 9.03 ± 0.20) in both functional feeding groups (F (3, 13) = 296, P < 0.0001). The treatment δ15N values are cautiously interpreted as reflecting uptake and incorporation of microbe-derived 15N-metabolites (15NH4 or 15N-amino acids) into host tissues following nitrate reduction to ammonium pathways in the gut lumen. Microbial nitrate reduction to ammonium activities was assessed via the quantification of dissimilatory (nrfA) and assimilatory (nasA) nitrate reduction to ammonium gene transcripts. There were no significant differences between control and treatment groups within each insect groups. Overall, this study provides a demonstration of the feasibility of applying 15N-stable isotope analysis for investigating, potential symbiotic functions of freshwater insect gut microbiomes, despite the preliminary nature of the results.
REVIEW | doi:10.20944/preprints201809.0459.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: Nutrition; Amino acids; Leukocytes; Skeletal muscle; Gut; Liver.
Online: 24 September 2018 (13:20:58 CEST)
Glutamine is the most abundant and versatile amino acid in the body. In health and disease, the rate of glutamine consumption by immune cells is similar or greater than glucose. For instance, in vitro and in vivo studies have determined that glutamine is an essential nutrient for lymphocyte proliferation and cytokine production, macrophage phagocytic plus secretory activities and neutrophil bacterial killing. Glutamine release to the circulation and availability is mainly controlled by key metabolic organs, such as the gut, liver and skeletal muscles. During catabolic/hypercatabolic situations glutamine can become essential for metabolic function, but its availability may be compromised due to impairment of homeostasis in the inter-tissue metabolism of amino acids. For this reason, glutamine is currently part of clinical nutrition supplementation protocols and/or recommended for immune suppressed individuals. However, in a wide range of catabolic/hypercatabolic situations (e.g. ill/critically ill, post-trauma, sepsis, exhausted athletes) it is currently difficult to determine whether glutamine parenteral or enteral supplementation should be recommended based on the amino acid plasma concentration (glutaminemia). Although the beneficial immune based effects of glutamine supplementation is already established, many questions and evidence for positive in vivo outcomes still remain to be presented. Therefore, this paper provides an integrated review on how glutamine metabolism in key organs is important to cells of the immune system. We also discuss glutamine metabolism, action and important issues related to the effects of glutamine supplementation in catabolic situations.
ARTICLE | doi:10.20944/preprints201805.0084.v1
Subject: Biology, Animal Sciences & Zoology Keywords: Bacillus coagulans; intestinal function; gut microbiota; weaned piglet
Online: 4 May 2018 (05:31:44 CEST)
This research was to investigate beneficial impact and molecular mechanism of B. coagulans on piglets intestine. Twenty-four 21 days old weaned piglets were allotted to three treatments: control group (basal diet), B6 group (basal diet + 2×106 CFU/g B. coagulans), B7 group (basal diet + 2×107 CFU/g B. coagulans). The results showed that compared with control group, B6 and B7 group significantly decreased diarrhea rate and the concent of CHOL, GGT and DAO in plasma; decreased villus height and increase crypt depth in jejunum and ileum; increased the activities of SOD and CAT and decreased the concent of MDA and H2O2 in intestine. These data suggested that supplementing B. coagulans had beneficial impacts on promoting nutrients metabolism, maintaining intestinal integrity and alleviating oxidative stress and diarrhea. Futher research of molecular mechanisms showed that, these beneficial impacts were regulated by changing expression levels of related proteins (including HSP70, Caspase-3, Bax, Villin and Occludin), and genes (including RPL4, IFN-α, IFN-β, IFN-γ, MX1, MX2, OAS1, IL-1β, IL-4, CXCL-9, CCL-2, AQP3, SGLT-1, LPL, INSR and b0,+AT), and altering community composition of gut microbiota (particularly family Clostridiaceae, Enterobacteriaceae, and Veillonellaceae and genus Prevotella, Turicibacter, and Lactobacillus).
REVIEW | doi:10.20944/preprints202110.0134.v1
Subject: Medicine & Pharmacology, Other Keywords: Probiotics; Gut microbiota; Obesity; Insulin resistance; Type 2 Diabetes
Online: 8 October 2021 (10:52:45 CEST)
Background: Obesity and diabetes are two metabolic disorders linked by an inflammatory process named insulin resistance (IR). Various research on the role of gut microbiota in developing obesity and its associated disorders has led to the growing interest in probiotic supplementation. Considering the life-threatening complications of diabesity this mini-review explored the effects of probiotic supplementation on IR in obesity-associated diabetes. Method: This review is based on recent articles from 2005-2020, studying the role of probiotic supplementation on glucose and insulin parameters in healthy and diabetic mouse models. Result: Probiotic supplementation altered the gut microbiota composition, increased short-chain fatty acid production, and decreased pro-inflammatory cytokines. Additionally, they decreased intestinal permeability, circulating lipopolysaccharide, and metabolic endotoxemia hence improved insulin sensitivity and reduced obesity. Although multi-strain probiotic supplementation showed greater benefits than single strain interventions, variations in the concentration of probiotics used and the duration of treatment also influenced the results. Conclusion: Probiotic supplementation could manipulate the gut microbiota by reducing intestinal permeability, inflammation and ameliorate IR and obesity-associated diabetes in animal models which requires further long-term clinical studies in humans.
ARTICLE | doi:10.20944/preprints202010.0333.v1
Subject: Life Sciences, Biochemistry Keywords: Anaerobic gut fungi; sequence-guided isolation; Neocallimastigomycota SK4 lineage
Online: 15 October 2020 (16:25:34 CEST)
We report on the isolation of the previously uncultured Neocallimastigomycota SK4 lineage by two independent research groups from a wild aoudad sheep rumen sample (Texas, USA) and an alpaca fecal sample (Baden-Württemberg, Germany). Isolates from both locations showed near identical morphological and microscopic features, forming medium-sized white filamentous colonies with a white center of sporangia on agar roll tubes and a heavy biofilm in liquid media. Microscopic analysis revealed monocentric thalli, and spherical polyflagellated zoospores with 7–20 flagella. Zoospore release occurred through an apical pore as well as by sporangial wall rupturing, a duality that is unique amongst described AGF strains. Isolates were capable of growing on a wide range of mono-, oligo-, and polysaccharides substrates. Phylogenetic assessment based on the D1-D2 large rRNA subunit (D1-D2 LSU) and internal transcribed spacer-1 (ITS-1) regions demonstrated high sequence identity (minimum identity of 99.07% and 96.96%, respectively) between all isolates; but low sequence identity (92.4% and 86.7%, respectively) to their closest cultured relatives. D1-D2 LSU phylogenetic trees grouped the isolates as a new monophyletic clade within the Orpinomyces-Neocallimastix-Pecoramyces-Feramyces-Ghazallamyces supragenus group. D1-D2 LSU and ITS-1 sequences from the obtained isolates were either identical, or displayed extremely high sequence similarity to sequences recovered from the same Aoudad sheep sample on which isolation was conducted, as well as several sequences recovered from domestic sheep and few other herbivores. Interestingly, members of the SK4 clade seem to be encountered in animals grazing on summer pasture. We hence propose accommodating these novel isolates in a new genus, Aestipascuomyces (derived from the Latin word for “summer pasture”), and a new species, A. dupliciliberatus. The type strain is Aestipascuomyces dupliciliberatus strain R4.
CONCEPT PAPER | doi:10.20944/preprints202004.0358.v1
Subject: Life Sciences, Microbiology Keywords: MDR typhoid; metal resistant genes; water toxicity; gut microbiome
Online: 20 April 2020 (02:27:07 CEST)
AMR and drug void have caused huge panic today with few thousand death per year. MDR Typhoid was a serious old disease and caused serious health hazard in humen and animals demanding an update on molecular biology of the status on transferable genetic elements. R-plasmids combined in F’-plasmid and the new MDR conjugative plasmids were shown abundant in Sanmonella ranging 70-440kb with similarities. BlaTEM, blaCTX-M, blaOXA, blaNDM mdr genes were abundant in >50 plasmids analyzed and metal resistant gene clusters are predominant in most large plasmids. Among the acetyltransferase all catA1, aacA1 and aac-1b-cr genes were located. Abundant streptomycin phosphotransferases (StrAB) and rarely colistin resistant Mcr-5/9 phosphoethanolamine–lipid A transferase were detected. Altered isomeric dihydropterote synthases (Sul1/2/3) were present giving sulfamethoxazole resistance and dhfr gene frequently associated giving trimethoprim resistance. Metal resistant gene clusters like SilABC (CusABC), PcoAB, RcnA, terABC, and merABCXT etc were found in many Salmonella enterica plasmids. Toxin genes like HipA and virulence genes like spvABD were located in few plasmids increasing virulence and pathogenesis. Drug efflux genes tetA or tetB and OqxB, floR, CmlA were frequent where as QepA and EamA genes were rarely seen. Thus, Salmonella metal resistant genes combined with antibiotic resistant genes has tried to overcome the both toxic antibiotics and metalions causing Typhoid AMR. Such acquisition spreads salmoniasis in the live stocks (pig, cow, chicken) where toxic soil and water dominate increasing chance of MDR typhoid in human.
Subject: Medicine & Pharmacology, Nutrition Keywords: Alzheimer’s disease; lactoferrin; cognitive function; gut microbiota; amyloid β
Online: 17 February 2020 (01:00:26 CET)
Existing evidence suggest that lactoferrin might be beneficial for Alzheimer’s disease. We aimed to determine the effects of lactoferrin intervention on cognitive function from APP/PS1 mice, and possible mechanisms involved in. Both young and middle-aged male APP/PS1 mice were divided into control and lactoferrin group with 16 weeks’ intervention. Lactoferrin intervention had no effects on cognitive function from both young and middle-aged mice, and no key markers involved in Aβ, tau pathology, neuro-inflammation and synaptic plasticity were altered post lactoferrin intervention. In regards to gut microbiota profiles, in the young mice, lactoferrin elevated α diversity index including ACE and Chao 1, and reduced the relative abundance of the genera Bacteroides and Alistipes and elevated Oscillibacter, in addition, Oscillibacter, Anaerotruncus, EF096579_g, EU454405_g, Mollicutes_RF39, EU474361_g, EU774448_g, and EF096976_g were specifically abundant post Lf intervention via LEfSe analysis. In the middle-aged mice, the relative abundance of the phylum Proteobacteria, as well as the genera Oscillospira, Coprococcus and Ruminococcus was significantly reduced post Lf intervention, additionally, S24_7, Bacteroidia, Bacteroidetes and Methylobacterium were specific via LEfSe analysis post lactoferrin intervention. In conclusion, dietary lactoferrin might be beneficial for gut microbiota homeostasis although might have no effects on cognition.
ARTICLE | doi:10.20944/preprints201908.0132.v1
Subject: Medicine & Pharmacology, Psychiatry & Mental Health Studies Keywords: schizophrenia; inflammation; oxidative stress; neuro-immune; gut bacteria; antioxidants
Online: 11 August 2019 (14:58:43 CEST)
In schizophrenia, a single latent trait underlies psychosis, hostility, excitation, mannerism, negative (PHEMN) symptoms, formal thought disorders (FTD) and psychomotor retardation (PMR). Schizophrenia is accompanied by a breakdown of gut and blood-brain-barrier (BBB) pathways, increased tryptophan catabolite (TRYCAT) levels, bacterial translocation, and lowered natural IgM and paraoxonase (PON)1 activity. The aim of this study was to examine the factor structure of schizophrenia symptom domains and the biomarker correlates of these factors. We recruited 80 patients with schizophrenia and 40 healthy subjects and assessed the IgA/IgM responses to paracellular/transcellular (PARA/TRANS) ratios, IgA responses to TRYCATs, natural IgM to malondialdehyde and Gram-negative bacteria, and PON1 enzymatic activity.Direct Hierarchical Exploratory Factor Analysis showed a bifactorial oblique model with a) a general factor which loaded highly on all symptom domains, named overall severity of schizophrenia (“OSOS”); and b) a single-group factor (SGF) loading on negative symptoms and PMR. We found that 40% of the variance in the OSOS score was explained by IgA/IgM to PARA/TRANS ratio, male sex and education while 36.9% of the variance in SGF score was explained by IgA to PARA/TRANS, IgM to Gram-negative bacteria, female sex (positively associated) and IgM to MDA, and PON1 activity (negatively associated). Schizophrenia phenomenology comprises two biologically-validated dimensions, namely a general OSOS dimension and a single-group negative symptom dimension, which are associated with a breakdown of gut/BBB barriers, increased bacterial translocation and lowered protection against oxidation, inflammation and bacterial infections through lowered PON1 and natural IgM.
ARTICLE | doi:10.20944/preprints201902.0182.v1
Subject: Medicine & Pharmacology, Psychiatry & Mental Health Studies Keywords: schizophrenia; inflammation; neuro-immune; oxidative stress; TRYCATs; leaky gut
Online: 19 February 2019 (12:14:29 CET)
Deficit schizophrenia is characterized by leaky tight and adherens junctions and bacterial translocation. Here we examine whether (deficit) schizophrenia is accompanied by leaky paracellular, transcellular and vascular barriers in the gut and blood brain barriers. We measured IgA responses to occludin, claudin-5, E-cadherin and β-catenin (paracellular pathway, PARA), talin, actin, vinculin and epithelial intermediate filament (transcellular pathway, TRANS) and plasmalemma vesicle-associated protein (PLVAP, vascular pathway) in 78 schizophrenia patients and 40 controls. IgA responses to claudin-5, E-cadherin and β-catenin, the sum of the four PARA proteins and the ratio PARA/TRANS were significantly higher in deficit schizophrenia than in non-deficit schizophrenia and controls. A large part of the variance in PHEMN (psychosis, hostility, excitation, mannerism and negative) symptoms, psychomotor retardation, formal thought disorders, verbal fluency, word list memory, word list recall and executive functions was explained by the PARA/TRANS ratio coupled with plasma IgA responses to Gram-negative bacteria, IgM to malondialdehyde, CCL-11 (eotaxin), IgA levels of the ratio of noxious to more protective tryptophan catabolites (NOX/PRO TRYCATs) and a plasma immune activation index. Moreover, IgA levels to Gram-negative bacteria were significantly associated with IgA to E-cadherin, β-catenin and PLVAP, while IgA levels to claudin-5 were significantly predicted by IgA to E-cadherin, NOX/PRO TRYCAT ratio, Gram-negative bacteria and CCL11. The phenomenology of the deficit syndrome is to a large extent explained by the cumulative effects of lowered natural IgM, breakdown of the paracellular and vascular pathways, increased bacterial translocation, peripheral immune-inflammatory responses and indices of BBB breakdown.
REVIEW | doi:10.20944/preprints201901.0170.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: gut microbiota; macrophages; TLR mimicry; immunoepigenetics; metabolism; sterile inflammation
Online: 17 January 2019 (03:05:26 CET)
Perturbation in the microbial population/colony index has harmful consequences on human health. Both biological and social factors influence the composition of the gut microbiota and promote gastric diseases. Changes in the gut microbiota manifest in disease progression owing to epigenetic modification in host which influences differentiation and function of immune cells adversely. Uncontrolled use of antibiotics; chemotherapeutic drugs and change in the diet pattern usually contribute to the changes in the colony index of sensitive strains known to release microbial content in the tissue micromillieu. Ligands released from dying microbes induce TLR mimicry on interaction with TLR abnormally which skew hypoxia and sterile inflammation contributing to severity of disease like IBD autoimmunity and cancer. Various modalities/interventions practiced across the globe and future strategies for microbiota based therapeutic approaches with special emphasis on tumor and inflammatory diseases are reviewed here. Therefore the major aim and scope of this manuscript is to both discuss various modalities/interventions across the globe and to design future microbiota based therapeutic approaches for mitigating the burden with special emphasis on tumor and Inflammatory diseases.
REVIEW | doi:10.20944/preprints201809.0215.v1
Subject: Medicine & Pharmacology, Dermatology Keywords: gut microbiota; skin microbiota; inflammation; psoriasis; psoriatic arthritis; dysbiosis
Online: 12 September 2018 (07:49:33 CEST)
Psoriasis is a chronic inflammatory disease characterized by skin lesions. Psoriasis development has been associated both with genetic and environmental factors. Though skin and gut microbiota has been implicated in number of pathologies including atopic dermatitis, inflammatory bowel disease, Crohn’s disease, allergy, obesity, its role has been poorly studied in psoriatic disease, which incorporates both psoriasis and psoriatic arthritis. This literature review summarizes the most recent and major findings on microbiota features in psoriatic disease as well as gives immune system role in the given condition. Despite conflicting findings, psoriasis patients were frequently found to have distinct microbial composition in both skin and guts especially in the major bacterial phyla, Firmicutes, Bacteroidetes, and Akkermansia. Furthermore, bacterial DNA has been found in psoriatic patients both locally and systemically, and altogether suggesting role of bacteria in the chronic disease and future studies in this field.
REVIEW | doi:10.20944/preprints201806.0152.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: protein; skeletal muscle; sarcopenia; gut microbiome; metabolome; diet; supplementation
Online: 11 June 2018 (11:05:04 CEST)
Muscle mass, strength and physical function are known to decline with age. This is associated with the development of geriatric syndromes including sarcopenia and frailty. These conditions are associated with disability, falls, longer hospital stay, higher readmission rates, institutionalisation, osteoporosis, and death. Moreover, they are associated with reduced quality of life, as well as substantial costs to health services around the world. Dietary protein is essential for skeletal muscle function. Older adults have shown evidence of anabolic resistance, where greater amounts of protein are required to stimulate muscle protein synthesis and therefore require higher daily amounts of dietary protein. Research shows that resistance exercise has the most beneficial effect on preserving skeletal muscle. A synergistic effect has been noted when this is combined with dietary protein, yet studies in this area lack consistency. This is due, in part, to the variation that exists within dietary protein, in terms of dose, quality, source, amino acid composition and timing. Research has targeted participants that are replete in dietary protein with negative results. Inconsistent measures of muscle mass, muscle function, physical activity and diet are used. This review attempts to summarise these issues, as well as introduce the possible role of the gut microbiome and its metabolome in this area.
REVIEW | doi:10.20944/preprints202209.0021.v1
Subject: Medicine & Pharmacology, Other Keywords: herbal drugs; gut microbiota; antibiotic stewardship, uncomplicated infection, NSAID, homeostasis.
Online: 1 September 2022 (10:35:01 CEST)
Epithelial surfaces in humans are home to symbiotic microbes (i.e., microbiota) that influence the defensive function against pathogens depending on the health of the microbiota. Healthy microbiota contribute to the well-being of their host in general (e.g., via the gut-brain-axis), and their respective anatomical site in particular (e.g., oral, urogenital, skin or respiratory microbiota). Despite efforts towards a more responsible use of antibiotics, they are often prescribed for uncomplicated, self-limiting infections and can have a substantial negative impact on the gut microbiota. Treatment alternatives such as non-steroidal anti-inflammatory drugs may also influence the microbiota and thus can have lasting adverse effects. Herbal drugs offer a generally safe treatment option for uncomplicated infections of the urinary or respiratory tract. Additionally, their microbiota preserving properties allow for a more appropriate therapy of uncomplicated infections without contributing to an increase in antibiotic resistance or disturbing the gut microbiota. Here, herbal treatments may be a more appropriate therapy with a generally favorable safety profile.
REVIEW | doi:10.20944/preprints202012.0415.v1
Subject: Medicine & Pharmacology, Allergology Keywords: nutrition; brain; neurodevelopment; childhood; gut-brain axis; psychobiotics; macronutrients, micronutrients.
Online: 16 December 2020 (13:52:17 CET)
Proper nutrition is crucial for normal brain and neurocognitive development. Failure to optimize neurodevelopment early in life can have profound long-term implications for both mental health and quality of life. Although the first 1000 days of life represent the most critical period of neurodevelopment, the central and peripheral nervous systems continue to develop and change throughout life. All this time, development and functioning depend on many factors, including adequate nutrition. In this review, we outline the role of nutrients in cognitive, emotional, and neural development in infants and young children with special attention to the emerging roles of polar lipids and high quality (available) protein. Furthermore, we discuss the dynamic nature of the gut-brain axis and the importance of microbial diversity in relation to a variety of outcomes, including brain maturation/function and behavior are discussed. Finally, the promising therapeutic potential of psychobiotics to modify gut microbial ecology in order to improve mental well-being is presented. Here we show that the individual contribution of nutrients, their interaction with other micro-and macronutrients, and the way in which they are organized in the food matrix are of crucial importance for normal neurocognitive development.
ARTICLE | doi:10.20944/preprints202010.0466.v1
Subject: Life Sciences, Biochemistry Keywords: Amyotrophic lateral sclerosis; dietary fiber; gut microbiota; prognosis; vegetable fiber
Online: 22 October 2020 (21:26:36 CEST)
The gut microbiota has been suggested as an important factor in the pathogenic mechanisms of amyotrophic lateral sclerosis (ALS). This study aimed to investigate whether the intake of different kinds of dietary fiber was related to the disease progression rate (∆FS) and survival time. In total, 272 sporadic ALS patients diagnosed according to the revised EI Escorial criteria were recruited from March 2011 and were followed-up until the occurrence of events or the end of September 2020. The events included percutaneous endoscopic gastrostomy, tracheostomy, and death. Dietary fiber intake was calculated based on a 24-hour dietary recall and classified according to five major fiber-rich foods: vegetables, fruits, grains, legumes, and nuts/seeds. Among the total participants, the group with ∆FS values lower than the mean ∆FS (0.75) was noted in the highest tertiles of total and vegetable fiber intake. Participants with the highest tertile of vegetable fiber intake showed longer survival in the Kaplan–Meier analysis (p = 0.033). Notably, vegetable fiber intake was negatively correlated with pro-inflammatory cytokine (interleukin [IL]-1β, IL-6, and monocyte chemoattractant protein-1) levels in the cerebrospinal fluid. This study showed that vegetable fiber intake could influence the disease progression rate and survival time. Further clinical trials are needed to confirm whether dietary fiber supplementation improves the prognosis of ALS.
ARTICLE | doi:10.20944/preprints202008.0421.v1
Subject: Medicine & Pharmacology, Psychiatry & Mental Health Studies Keywords: deficit schizophrenia; cytokines; inflammation; neuro-immune; oxidative stress; leaky gut
Online: 20 August 2020 (03:24:47 CEST)
Current case definitions of schizophrenia (DSM-5, ICD), made through a consensus among experts, are not cross-validated and lack construct reliability validity. The aim of this paper is to explain how to use bottom-up pattern recognition approaches to construct a reliable and replicable nomothetic network reflecting the direct effects of risk resilience (RR) factors, and direct and mediated effects of both RR and adverse outcome pathways (AOPs) on the schizophrenia phenome. This study was conducted using data of 40 healthy controls and 80 patients with schizophrenia. Using partial least Squares (PLS) analysis, we found that 39.7% of the variance in the phenomenome (lowered self-reported quality of life) was explained by the unified effects of AOPs (IgA to tryptophan catabolites, LPS, and the paracellular pathway, cytokines, and oxidative stress biomarkers), the cognitome (memory and executive deficits), and symptomatome (negative symptoms, psychosis, hostility, excitation, mannerism, psychomotor retardation, formal thought disorders); 55.8% of the variance in the symptomatome was explained by a single trait extracted from AOPs and the cognitome; and 22.0% of the variance in the latter was explained by the RR (Q192R polymorphism and CMPAaase activity, natural IgM, and IgM levels to zonulin). There were significant total effects (direct + mediated) of RR and AOPs on the symptomatome and phenomenome. In the current study, we built a reliable nomothetic network that reflects the associations between RR, AOPs, and the phenome of schizophrenia and discovered new diagnostic subclasses of schizophrenia based on unified RR, AOPs, and phenome scores.
REVIEW | doi:10.20944/preprints201910.0189.v1
Subject: Life Sciences, Microbiology Keywords: microbiome; microbiota-gut-brain axis; ADHD; attention-deficit-hyperactive-disorder
Online: 17 October 2019 (09:04:10 CEST)
The latest research cumulates staggering information about the correlation between the microbiota-gut-brain axis and neurodevelopmental disorders. This review aims to shed light on the potential influence of the microbiome on the development of the most prevalent neurodevelopmental disease, attention-deficit-hyperactive disorder (ADHD). As the etiology and pathophysiology of ADHD are still unclear, finding viable biomarkers and effective treatment still represent a challenge. Therefore, we focused on factors that have been associated with a higher risk of developing ADHD while simultaneously influencing the microbial composition. We reviewed the effect of a differing microbial composition on neurotransmitter concentrations important in the pathophysiology of ADHD. Additionally, we deduced factors that correlate with a high prevalence of ADHD while simultaneously affecting the gut microbiome such as emergency c-sections, and premature birth as the former leads to a decrease of the gut microbial diversity and the latter causes neuroprotective Lactobacillus levels to be reduced. Also, we assessed nutritional influences such as breastfeeding, ingestion of short-chain fatty acids (SCFAs) and polyunsaturated fatty acids (PUFAs) on the host’s microbiome and development of ADHD. Finally, we discussed the potential significance of Bifidobacterium as a biomarker for ADHD, the importance of preventing premature birth as prophylaxis and nutrition as a prospective therapeutic measurement against ADHD.
ARTICLE | doi:10.20944/preprints201809.0387.v2
Subject: Biology, Animal Sciences & Zoology Keywords: behaviour/sociality; cleaner fish; gut-brain axis; poecilids; sticklebacks; zebrafish
Online: 18 February 2019 (15:43:41 CET)
Recent research has revealed surprisingly important connections between animals’ microbiome and social behaviour. Social interactions can affect the composition and function of the microbiome; conversely, the microbiome affects social communication by influencing the hosts’ central nervous system and peripheral chemical communication. These discoveries set the stage for novel research venues focusing on the evolution and physiology of animal social behaviour in relation to microbial transmission strategies. Here, we discuss the emerging roles of teleost fish model candidates and their key potential for advancing research fields linked to sociality and microbial regulation. We argue that fish models, such as the zebrafish, sticklebacks, guppies and cleaner-client dyads, will provide valuable insights into the roles of microbiome in shaping social behaviour and vice versa, while also being of direct relevance to the food and ornamental fish trades.
ARTICLE | doi:10.20944/preprints201901.0141.v1
Subject: Medicine & Pharmacology, Psychiatry & Mental Health Studies Keywords: schizophrenia; leaky gut; neuro-immune; inflammation; oxidative stress; TRYCATs; cytokines
Online: 15 January 2019 (07:17:55 CET)
In 2001, the first author of this paper reported that schizophrenia is associated with an increased frequency of the haptoglobin (Hp)-2 gene. The precursor of Hp-2 is zonulin, a molecule that affects intercellular tight junction integrity. Recently, we reported increased plasma IgA/IgM responses to Gram-negative bacteria in deficit schizophrenia indicating leaky gut and gut dysbiosis. The current study was performed to examine the integrity of the paracellular (tight and adherens junctions) and transcellular (cytoskeletal proteins) pathways in deficit versus non-deficit schizophrenia. We measured IgM responses to zonulin, occludin, E-cadherin, talin, actin and vinculin in association with IgA responses to Gram-negative bacteria, CCL-11, IgA responses to tryptophan catabolites (TRYCATs), immune activation and IgM to malondialdehyde (MDA) and NO-cysteinyl in 78 schizophrenia patients and 40 controls. We found that the ratio of IgM to zonulin + occudin / talin + actin + viculin (PARA/TRANS) was significantly greater in deficit than in non-deficit schizophrenia and higher in schizophrenia than controls and was significantly associated with increased IgA responses to Gram-negative bacteria. IgM responses to zonulin were positively associated with schizophrenia (versus controls), while IgM to occludin was significantly associated with deficit schizophrenia (versus non-deficit schizophrenia and controls). A large part of the variance (90.8%) in negative and PHEM (psychosis, hostility, excitation and mannerism) symptoms was explained by PARA/TRANS ratio, IgA to Gram-negative bacteria, IgM to E-cadherin and malondialdehyde (MDA) and memory dysfunctions, while 53.3% of the variance in the latter was explained by PARA/TRANS ratio, IgA to Gram-negative bacteria, CCL-11, TRYCATs and immune activation. The results show an upregulated paracellular pathway with breakdown of the tight and ahherens junctions and increased bacterial translocation in deficit schizophrenia. These dysfunctions in the intestinal paracellular route together with lowered natural IgM, immune activation and production of CCL-11 and TRYCATs contribute to the phenomenology of deficit schizophrenia.
ARTICLE | doi:10.20944/preprints202110.0076.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: coronary artery disease; gut microbiome; dysbiosis; obesity; Bacteroidetes; LPS; indoxyl sulfate
Online: 5 October 2021 (10:33:24 CEST)
Gut dysbiosis, alongside with high-fat diet and cigarette smoking, is considered one of the factors promoting coronary arterial disease (CAD) development. The present study aimed to research whether gut dysbiosis can increase bacterial metabolites concentration in the blood of CAD patients and what impact these metabolites can exert on endothelial cells. The gut microbiome of 15 CAD patients and age-matched 15 healthy controls was analyzed by metagenome sequencing. The in vitro impact of LPS and indoxyl sulfate at concentrations present in patients sera on endothelial cells was investigated. A metagenome sequencing analysis revealed gut dysbiosis in CAD patients, further confirmed by elevated levels of LPS and indoxyl sulfate in patients sera. CAD was associated with depletion of Bacteroidetes and Alistipes. LPS and indoxyl sulfate in meager concentrations demonstrated co-toxicity to endothelial cells inducing reactive oxygen species, E-selectin, and monocyte chemoattractant protein-1 (MCP-1) production and promoting thrombogenicity of endothelial cells confirmed by monocyte adherence. The co-toxicity of LPS and indoxyl sulfate was associated with harmful effects on endothelial cells, strongly suggesting that gut dysbiosis-associated increased intestinal permeability can initiate or promote endothelial inflammation and atherosclerosis progression.
ARTICLE | doi:10.20944/preprints202009.0584.v1
Subject: Life Sciences, Microbiology Keywords: fungal community; gut mycobiota; diversity; ITS metabarcoding; intestinal parasites; children; Mali
Online: 24 September 2020 (12:24:53 CEST)
Eukaryotic enteric pathogens (EEP) are a public health issue in tropical areas. Yet, their interactions with the gut mycobiota remain poorly understood. We conducted a cross-sectional study in Malian children to analyze the impact of EEP on the gut fungal community. EEP were assessed by qPCR and the gut mycobiota was characterized by ITS1-2 metabarcoding in stool samples collected from 296 children. The 100 controls, in whom no EEP was detected, were compared to: a) 196 children with ≥1 EEP; b) 91 with only Blastocystis; c) 35 with only Giardia intestinalis; and d) 12 with another (<1% each) EPP. The gut fungal community structure was homogenous in each children’s group. Linear size-effect discriminant analysis highlighted five relatively more abundant species, including Fusarium longipes and Penicillium caseifulvum, in children with ≥1 EEP, whereas 28, including Aspergillus sydowii and Microdochium colombiense were more abundant in controls. Fusarium, Pyxidiophora, and Stereum abundance was higher in Blastocystis-infected children, whereas Ogataea and Allocryptovalsa were more abundant in controls. Sordariales and Mortierellales abundance was higher in Giardia intestinalis-infected children, whereas Agaricales and Capnodiales abundance was higher in controls. In conclusion, EEP do not significantly alter the gut fungal community structure, and further studies are warranted to confirm our findings that particular taxa are associated with susceptibility or resistance to specific EEP.
ARTICLE | doi:10.20944/preprints202002.0435.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: encapsulated essential oils; coccidiosis vaccine; growth performance; broiler chickens; gut health
Online: 28 February 2020 (13:04:42 CET)
The present study was conducted to evaluate encapsulated essential oils as an alternative anticoccidial in coccidiosis vaccine challenged broiler chickens. A total of 600 day-old male broiler chicks were provided with no-added corn-soybean meal-based control diet or diets that contained either salinomycin or EO at 60 and 120 mg per kg of diet. On day 21, half of the control groups were orally challenged with a coccidiosis vaccine at 25 times higher than the recommended vaccine dose. During 22 to 28 days (i.e., one-week post coccidiosis vaccine challenge), the challenged chickens had decrease (P < 0.05) in body weight gain and feed intake but increase in feed conversion ratio compared with the non-challenged, naïve control chickens. However, dietary EO significantly counteracted (P < 0.05) coccidiosis vaccine-induced depression in body weight gain and feed intake. Increasing dietary EO linearly decreased (P < 0.05) the concentrations of the volatile fatty acids. Dietary SAL and EO affected gut morphology in chickens at 20 days posthatch. Increasing dietary EO linearly (P = 0.073) increased serum catalase activity. Collectively, our study shows that dietary EO increased coccidiosis vaccine-induced growth depression and altered gut physiology in broiler chickens.
ARTICLE | doi:10.20944/preprints201806.0193.v1
Subject: Life Sciences, Endocrinology & Metabolomics Keywords: aronia; ginseng; mushroom; pancreatectomy; type 2 diabetes; gut microbiome; insulin secretion
Online: 12 June 2018 (13:01:30 CEST)
The combination of freeze-dried aronia, red ginseng, ultraviolet-irradiated shiitake mushroom and natokinase (AGM; 3.4: 4.1: 2.4: 0.1) was examined to evaluate its effects on insulin resistance, insulin secretion and gut microbiome in a non-obese type 2 diabetic animal model. Pancreatectomized (Px) rats were provided high fat diets supplemented with either of 1) 0.5 g AGM (AGM-L), 2) 1 g AGM (AGM-H), 3) 1 g dextrin (control), or 4) 1g dextrin with 120 mg metformin (positive-control) per kg body weight for 12 weeks. AGM (1 g) contained 6.22 mg cyanidin-3-galactose, 2.5 mg ginsenoside Rg3 and 0.6 mg β-glucan. Px rats had decreased bone mineral density in the lumbar spine and femur and lean body mass in the hip and leg compared to the normal-control and AGM-L and AGM-H prevented the decrease. Visceral fat mass was lower in the control group than the normal-control group and its decrease was smaller by AGM-L and AGM-H. HOMA-IR was lower in descending order of the control, positive-control, AGM-L, AGM-H and normal-control groups. Glucose tolerance was deteriorated in the control group and it was improved by AGM-L and AGM-H more than in the positive-control group. Glucose tolerance is associated with insulin resistance and insulin secretion. Insulin tolerance indicated insulin resistance was highly impaired in diabetic rats, but it was improved in the ascending order of the positive-control, AGM-L and AGM-H. Insulin secretion capacity, measured by hyperglycemic clamp, was much lower in the control group than the normal-control group and it was improved in the ascending order of the positive-control, AGM-L and AGM-H. Diabetes modulated the composition of gut microbiome and AMG prevented the modulation of gut microbiome. In conclusion, AGM improved glucose metabolism by potentiating insulin secretion and reducing insulin resistance in insulin deficient type 2 diabetic rats. The improvement of diabetic status alleviated body composition changes and prevented changes of gut microbiome composition.
REVIEW | doi:10.20944/preprints202103.0712.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: dietary fibers; short chain fatty acid; gut microbiota; colorectal cancer prevention; epigenetics
Online: 29 March 2021 (22:22:00 CEST)
Dietary factors play an important role in shaping the gut microbiome which, in turn, regulates the molecular events in colonic mucosa. The composition and resulting metabolism of the gut microbiome have been implicated in the development of colorectal cancer (CRC). Diets low in dietary fibers and phytomolecules as well as other lifestyle-related factors may predispose to CRC. Emerging evidence demonstrates that the predominance of microbes, such as Fusobacterium nucleatum, can predispose the colonic mucosa to malignant transformation. Dietary and lifestyle modifications have been demonstrated to restrict the growth of potentially harmful opportunistic organisms. In this study, we aim to present evidence regarding the relationship of dietary factors to the gut microbiome and development of CRC.
REVIEW | doi:10.20944/preprints202006.0311.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: functional food; dietary supplement; phytochemicals; nutritional neuroscience; gut microbiome; personalized nutrition; Bangladesh
Online: 26 June 2020 (12:23:14 CEST)
Plants and plant-derived food products have been used for medicinal purposes since the ancient. Medicinal Plant-based functional foods or plant-based dietary compounds are a re-emerged interest for their therapeutic benefits and nutritive supports which has implicated in healthcare systems across the world. Neurological disorders are one of the greatest threats to public health and according to the World Health Organization, about 100 million people are affected globally by several neurological and mental ailments. In a traditional medication system, medicinal plants have been applied as both neuro-therapeutic purposes and micro-macro nutrients provider for the wellbeing of psychological states e.g. anti-depressant, anti-anxiety, anti-convulsions, anti-dementia, anti-psychotic, etc. Herein, it is a topic of great interest to present a conceptual aspect by reviewing relevant scientific literature about the plant-based functional foods or bioactive phytochemicals for the prevention and treatment of mental and neurological disorders. From the literature assessment, we have found that nutritional neuroscience is becoming an advanced research discipline and there has been a growing pile of evidence concerning the therapeutic use of plant-based functional foods and/or plant-derived food compounds for the management of neurologic health, evolving with promising impact over the time.
ARTICLE | doi:10.20944/preprints202101.0541.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Bioremediation; gut microbiota; lactic acid bacteria, Enterobacterales; lead; cadmium; aluminum; Probiotics; ICP-MS
Online: 26 January 2021 (13:26:26 CET)
Hazardous toxic metals, such as lead and cadmium, and to a lesser extent aluminum, are extensively recognized as detrimental for health following ingestion within food and water, or following inhalation. Gut and food-derived microbes, by interacting with heavy metals, may actively or passively modulate their bioavailability inside the gut, either by adsorption or by sequestration. Such a bioremediation within the gut implies the selection of safe microbes, based on their specific capacities to immobilize metals. We investigated the metal removal ability of 225 bacteria toward the potential harmful trace elements lead, cadmium and aluminum in vitro, using Inductively Coupled Plasma Mass Spectrometry analysis. Interspecies and intraspecies comparisons were addressed and discussed among bacteria from the phylum Firmicutes, which are mostly lactic acid bacteria, including Lactobacillus spp, with some Lactococcus, Pediococcus and Carnobacterium representatives, Actinobacteria as well as Proteobacteria. The effect on mixture of lead and cadmium was also investigated. Although the purpose of such a screening is so far not to elucidate each of the various strain specific- and metal dependent- mechanisms of heavy metal removal, we identified potential bacteria which are able to alleviate Pb(II) and Cd(II) concerns in order to propose performing candidate probiotics for metal xenobiotic bioremediation.
REVIEW | doi:10.20944/preprints202007.0305.v1
Subject: Life Sciences, Immunology Keywords: spondyloarthritis; HLA-B27; pathogenesis; inflammation; arthritogenic peptides; unfolded protein response; ERAP1; gut dysbiosis
Online: 14 July 2020 (11:39:13 CEST)
Spondyloarthritis comprises of a group of inflammatory diseases of the joints and spine with various clinical manifestations. The group includes ankylosing spondylitis, reactive arthritis, psoriatic arthritis, arthritis associated with inflammatory bowel disease, and undifferentiated spondyloarthritis. The exact etiology and pathogenesis of spondyloarthritis are still unknown, but five hypotheses explaining the pathogenesis exist. These hypotheses suggest that spondyloarthritis is caused by arthritogenic peptides, an unfolded protein response, HLA-B27 homodimer formation, malfunctioning endoplasmic reticulum aminopeptidases, and, last but not least, gut inflammation and dysbiosis. Here we discuss the five hypotheses and the evidence supporting each. In all of these hypotheses, HLA-B27 plays a central role. It is likely that a combination of these hypotheses, with HLA-B27 taking center stage, will eventually explain the development of spondyloarthritis in predisposed individuals.
ARTICLE | doi:10.20944/preprints201907.0293.v1
Subject: Medicine & Pharmacology, Psychiatry & Mental Health Studies Keywords: depression; bipolar disorder; gut; bacterial translocation; LPS; oxidative stress; neuro-immune; immunology; psychiatry
Online: 26 July 2019 (00:38:09 CEST)
Major depression (MDD) is accompanied by higher serum IgM/IgA responses to LPS of Gram-negative bacteria, suggesting increased bacterial translocation and gut dysbiosis. Gut dysbiosis may occur in bipolar disorder (BD) and there are differences between MDD and BD type 1 (BP1) and -2 (BP2) in nitro-oxidative stress biomarkers associated with leaky gut. This study examines serum IgM/IgA responses directed to LPS of 6 Gram-negative bacteria in 29 BP1, 37 BP2, 44 MDD and 30 healthy individuals. MDD plus BD was best discriminated from controls by increased IgM/IgA responses to Pseudomonas aeruginosa. BP1 patients showed higher IgM responses to Morganella morganii as compared with MDD and BP2 patients. Patients with melancholia showed higher IgA responses to Citrobacter koseri as compared to controls and non-melancholic depression. The total score on the Hamilton Depression Rating Scale was significantly associated with IgA responses, especially C. koseri. IgG responses to oxidized low-density lipoprotein were significantly associated with signs of increased bacterial translocation. In conclusion, not only MDD but also BP1 and BP2 are accompanied by an immune response due to the increased load of plasma LPS of gut commensal bacteria while these aberrations in the gut-brain axis are most pronounced in BP1 and patients with melancholic features. Activated oxidative stress pathways and autoimmune responses to oxidative specific epitopes in mood disorders may be driven by a breakdown in gut paracellular, transcellular and/or vascular pathways. If replicated, drugs that protect the integrity of the gut barrier may offer novel therapeutic opportunities for BP1 and MDD.
COMMUNICATION | doi:10.20944/preprints202204.0042.v1
Subject: Biology, Other Keywords: IBD; UC; UPR; ex vivo organ; DNBS; Gut-Ex-Vivo System; GEVS; ferroptosis; apoptosis
Online: 6 April 2022 (10:40:35 CEST)
Background: IBD is a spectrum of pathologies characterized by dysregulated immune activation leading to uncontrolled response against intestinal, thus resulting in chronic gut inflammation and tissue damage. Due to its complexity, the molecular mechanisms responsible for disease onset and progression are still elusive, thus requiring intense research effort. In this context, the development of models recapitulating the etiopathology of IBD is critical.Methods: Colon from C57BL/6 or BALB/c mice were cultivated in a gut-ex-vivo system (GEVS), exposed 5h to DNBS 1,5 or 2,5 mg/ml, and the main hallmarkers of IBD were evaluated.Results: Gene expression analysis revealed a DNBS-induced: i) compromised Tight junction organization, responsible for tissue permeability dysregulation; induction of ER stress, and iii) tissue inflammation in colon of C57BL/6 mice. Moreover, the concomitant DNBS-induced apoptosis and ferroptosis pathways was evident in colon from both BALB/c and C57BL/6 mice.Conclusions: Overall, we have provided results demonstrating that GEVS is a consistent, reliable, and cost-effective system for modeling DNBS-induced IBD, useful for studying the onset and progression of human disease at the molecular level, while also reducing animal suffering.
REVIEW | doi:10.20944/preprints202006.0058.v1
Subject: Medicine & Pharmacology, Psychiatry & Mental Health Studies Keywords: depression; leaky gut; microbiota; cytokines; neuroimmunomodulation; oxidative stress; glia; blood-brain barrier; LPS; TLR
Online: 5 June 2020 (15:06:57 CEST)
In the last three decades, the robust scientific data emerged, demonstrating that the immune-inflammatory response is a fundamental component of the pathophysiology of major depressive disorder (MDD). Psychological stress and various inflammatory comorbidities contribute to such immune activation. Still, this is not uncommon that patients with depression do not have defined inflammatory comorbidities, and alternative mechanisms of immune activation need to take place. The gastrointestinal (GI) tract, along with gut-associated lymphoid tissue (GALT), constitutes the largest lymphatic organ in the human body and forms the biggest surface of contact with the external environment. It is also the most significant source of bacterial and food-derived antigenic material. There is a broad range of reciprocal interactions between the GI tract, intestinal microbiota, increased intestinal permeability, activation of immune-inflammatory response, and the CNS that has crucial implications in brain function and mental health. This intercommunication takes place within the microbiota-gut-immune-glia (MGIG) axis, and glial cells are the main orchestrator of this communication. A broad range of factors, including psychological stress, inflammation, dysbiosis and other, may compromise the permeability of this barrier. This leads to excessive bacterial translocation and the excessive influx of food-derived antigenic material that contributes to activation of the immune-inflammatory response and depressive psychopathology. This chapter summarizes the role of increased intestinal permeability in MDD and mechanisms of how the "leaky gut" may contribute to immune-inflammatory response in this disorder.
REVIEW | doi:10.20944/preprints201901.0275.v1
Subject: Medicine & Pharmacology, Other Keywords: canine enteroid/colonoids; gut-on-a-chip; translational medicine; Alzheimer’s disease; canine cognitive disfunction
Online: 28 January 2019 (10:30:57 CET)
Identifying appropriate animal models is critical in developing translatable in vitro and in vivo systems for therapeutic development and investigating disease pathophysiology. These animal models should have direct biological and translational relevance to the underlying disease they are supposed to mimic. Aging dogs naturally develop a cognitive decline in many aspects including learning and memory, but also exhibit human-like individual variability in the aging process. Neurodegenerative processes that can be observed in both human and canine brains include the progressive accumulation of β-amyloid (Aβ) found as diffuse plaques in the prefrontal cortex, including the gyrus proreus, the hippocampus, and in the cerebral vasculature. A growing body of epidemiological data shows that human patients with neurodegenerative diseases have concurrent intestinal lesions, and histopathological changes in the gastrointestinal (GI) tract occurs decades that evolve before neurodegenerative changes. Gut microbiome alterations also have been observed in many neurodegenerative diseases including Alzheimer’s and Parkinson’s diseases, and inflammatory CNS diseases. Interestingly, only recently has the dog gut microbiome been recognized to more closely resemble in composition and in functional overlap with the human gut microbiome as compared to rodent models. This article aims to review the physiology of the gut-brain axis (GBA), and its involvement with neurodegenerative diseases in dogs and humans. Additionally, we outline the advantages and disadvantages of traditional in vitro and in vivo models and discuss future research directions investigating major human neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases using dogs.
REVIEW | doi:10.20944/preprints202202.0271.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: oral microbiome; systemic disease; gingival sulcus; junctional epithelium; mucosal barrier; biofilm; leaky gut; leaky gum
Online: 22 February 2022 (11:18:15 CET)
The oral cavity is the gateway for microorganisms into your body where they disseminate not only to the directly connected respiratory and digestive tracts, but also to the many remote organs. Oral microbiota, traveling to the end of the intestine and circulating our body through blood vessels, not only affect a gut microbiome profile, but also many systemic diseases. By gathering information accumulated from the era of focal infection theory to the age of revolution in microbiome research, we propose a pivotal role of “leaky gum”, as an analogy of “leaky gut”, to underscore the importance of the oral cavity in systemic health. The oral cavity has unique structures, the gingival sulcus (GS) and the junctional epithelium (JE) below the GS, which are rarely found anywhere else in our body. The JE is attached to the tooth enamel and cementum by hemidesmosome (HD), which is structurally weaker than desmosome and is thus vulnerable to microbial infiltration. In the GS, microbial biofilms can build up for life, unlike the biofilms on the skin and intestinal mucosa that fall off by natural process. Thus, we emphasize that the GS and the JE are the weakest leaky point for microbes to invade human body, making the leaky gum just as important as, or even more important than, the leaky gut.
ARTICLE | doi:10.20944/preprints202108.0104.v1
Subject: Biology, Anatomy & Morphology Keywords: quantitative metagenomics; microbiome; obesity; gut microbiota; microbial DNA extraction; sequencing; Simulation; Oxford Nanopore Technologies; MinION
Online: 4 August 2021 (09:44:24 CEST)
Background: The gut microbiome plays a major role in chronic diseases, of which several are characterized by an altered composition and diversity of bacterial communities. Large-scale sequencing projects allowed characterizing the perturbations of these communities. However, translating these discoveries into clinical applications remains a challenges. To facilitate routine implementation of microbiome profiling in clinical settings, portable, real-time, and low-cost sequencing technologies are needed. Results: Here, we propose a computational and experimental protocol for whole genome quantitative metagenomics studies of human gut microbiome with Oxford Nanopore sequencing technology (ONT) that could be applied to other microbial ecosystems. We developed a bioinformatic protocol to analyse ONT sequences taxonomically and functionally and optimized pre-analytic protocols including stool collection and DNA extraction methods to maximize read length. This is a critical parameter for the sequence alignment and classification. Our protocol was evaluated using simulations of metagenomic communities which reflect naturally occuring compositional variations. Next, we validated both protocols using stool samples from a bariatric surgery cohort, sequenced with ONT, Illumina and SOLiD technologies. Results revealed similar diversity and microbial composition profiles. Conclusion: This protocol can be implemented in the clinical or research setting, bringing rapid personalized whole genome profiling of target microbiome species.
REVIEW | doi:10.20944/preprints201809.0185.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: predictive preventive personalized medicine; Lactobacillus; Bifidobacterium; probiotics, gut microbiota; patient phenotype, individualized medicine; metabolic syndrome
Online: 11 September 2018 (06:00:03 CEST)
The modification the gut microbiota in metabolic syndrome and associated chronic diseases is among leading tasks of microbiome research and needs for clinical use of probiotics. Evidence lack for the implications for microbiome modification to improve metabolic health in particular when applied impersonalized. Probiotics have tremendous potential in personalized nutrition and medicine to develop healthy diets. The aim was to to conduct comprehensive overview of recent updates of role of microbiota on human health and development of metabolic syndrome and efficacy of microbiota modulation considering specific properties of probiotic strain and particular aspects of metabolic syndrome and patient`s phenotype to fill the gap between probiotic product and individual to facilitate development of individualized / personalized probiotic and prebiotic treatments. We discuss the relevance of using host phenotype-associated biomarkers, those based on imaging and molecular and patrient`s history, reliable and accessible to facilitate person-specific appication of probiotics and prebiotic substances. Microbiome phenotypes can be parameters of predictive medicine to recognize patient`s predispositions and evaluate treatment responses; the number of phenotype markers can be effectively involved to monitor microbiome modulation. The studied strain-dependent properties of probiotic strains are potentially relevant for individualized treatment for gut and distant sites microbiome modulation. The evidence regarding probiotic strains properties can be taken to account via pathophysiology-based approach for most effective individualized treatment via gut, oral and vaginal and other sites microbiome modulation according to phenotype of the patient providing individualized and personalized medical approaches. Preventive potential of probiotics is strong and well-documented. Recommendations for individualized clinical use of probiotics, and for probiotic studies design have been suggested.
REVIEW | doi:10.20944/preprints202211.0328.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: Probiotics; gut flora; gastrointestinal diseases; Lactobacillus; Bifidobacteria; placebo; Diarrhea; microbiota; composite; sin-gle-organisms; Ulcerative Colitis
Online: 17 November 2022 (08:53:58 CET)
Probiotics are namely yeast and bacteria which are regarded as dietary supplements and food. Many probiotics are being commonly used now, the most frequently used, lactic acid bacteria are called Lactobacillus and Bifidobacterium. Many of the diseases associated with GIT are related to microbiota found in GIT, an imbalance of which causes gastrointestinal diseases. Probiotics, in light of scientific literature, are thought to play an important role in relieving symptoms of many diseases associated with GIT, i.e. beneficially regulating the microbiota composition. In the present review, we aimed to highlight the main considerations for main probiotic formulations to date. This study reviews the role of different probiotic formulations introduced so far in treating GI diseases in cohort ageing ≤18 years. We searched PubMed and Clinicaltrials.gov without any restrictions. This study comprises the descriptive and comparative analysis between Single-organism and Composite probiotics. These GI diseases include NEC, FAP, AGE, Acute Diarrhea, Ulcerative Colitis and etc. The results have been categorized according to title and outcomes. The positive outcomes emphasize the drug’s effectiveness in improving health and the negative outcome elaborates on the adverse effects the drug may have shown. Conclusively, discussed practices will assist in reducing GI disorders and strengthening the gut. Further insight into the various gut microbes and microbiomes with specific demographic is recommended.
ARTICLE | doi:10.20944/preprints202108.0225.v1
Subject: Biology, Physiology Keywords: microglia; gut-brain axis; antibiotics; glutamatergic synapses; hippocampus; patch clamp; hippocampal slices.; microbiota; neurons; glutamatergic trasmission
Online: 10 August 2021 (10:04:00 CEST)
‘Dysbiosis’ of the adult gut microbiota, in response to challenges such as infection, altered diet, stress, and antibiotics treatment has been recently linked to pathological alteration of brain func-tion and behavior. Moreover, gut microbiota composition constantly controls microglia matura-tion as revealed by morphological observations and gene expression analysis. However, it is un-clear whether gut microbiota influences microglia functional properties and crosstalk with neu-rons, known to shape and modulate synaptic development and function. Here, we investigated how antibiotic mediated alteration of the gut microbiota influences microglial and neuronal functions in adult mice hippocampus. Hippocampal microglia from adult mice treated with oral antibiotics exhibited increased microglia density, altered basal patrolling activity, and impaired process rearrangement in response to damage. Patch clamp recordings at CA3-CA1 synapses revealed that antibiotics treatment alters neuronal functions, reducing spontaneous postsynaptic glutamatergic currents and decreasing synaptic connectivity, without reducing dendritic spines density. The effect of dysbiosis on neuronal functions are mediated by microglia-neuron cross-talk through the CX3CL1-CX3CR1 axis, as antibiotics treatment of CX3CR1 deficient mice, mod-ulates microglia density and processes rearrangement leaving unaltered synaptic function. To-gether, our findings show that the antibiotics alteration of gut microbiota impairs synaptic effi-cacy, probably through CX3CL1-CX3CR1 signaling supporting microglia as a major player in in the gut-brain axis, and in particular in the gut microbiota-to-neuron communication pathway.
ARTICLE | doi:10.20944/preprints202103.0001.v1
Subject: Life Sciences, Biochemistry Keywords: non-alcoholic fatty liver disease; xylo-oligosaccharides; metabolites; gut microbiota; biclustering; high fat diet; microRNAs; rats
Online: 1 March 2021 (12:28:31 CET)
We have shown that prebiotic xylo-oligosaccharides (XOS) increased beneficial gut microbiota (GM) and prevented high fat diet-induced hepatic steatosis, but the mechanisms behind these effects are not clear. We studied whether XOS affects adipose tissue inflammation and insulin signaling, and whether the GM and fecal metabolome explain associated patterns. XOS was supplemented or not with high (HFD) or low (LFD) fat diet for 12-weeks in male Wistar rats (n = 10/group). Previously analyzed GM and fecal metabolites were biclustered to reduce data dimensionality and identify interpretable groups of co-occurring genera and metabolites. Based on our findings, biclustering provides a useful algorithmic method for capturing such joint signatures. On the HFD, XOS-supplemented rats showed lower number of adipose tissue crown-like structures, increased phosphorylation of AKT in liver and adipose tissue as well as lower expression of hepatic miRNAs. XOS-supplemented rats had more fecal glycine and less hypoxanthine, isovalerate, branched chain amino acids and aromatic amino acids. Several bacterial genera were associated with the metabolic signatures. In conclusion, the beneficial effects of XOS on hepatic steatosis involved decreased adipose tissue inflammation and likely improved insulin signaling, which were further associated with fecal metabolites and GM.
REVIEW | doi:10.20944/preprints201907.0196.v1
Subject: Biology, Physiology Keywords: Myalgic Encephalomyelitis, Chronic Fatigue Syndrome, ME/CFS, diagnosis, metabolism, mitochondria, inflammation, immune system, signaling, gut microbiota.
Online: 16 July 2019 (12:41:26 CEST)
The underlying molecular basis of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is not well understood. Characterized by chronic, unexplained fatigue, a disabling payback following exertion (“post-exertional malaise”) and variably presenting, multi-system symptoms, ME/CFS is a complex disease which demands concerted biomedical investigation from disparate fields of expertise. ME/CFS research and patient treatment have been challenged by the lack of diagnostic biomarkers and finding these is a prominent direction of current work. Despite these challenges, modern research demonstrates a tangible biomedical basis for the disorder across many body systems. This evidence is largely comprised of disturbances to immunological and inflammatory pathways, autonomic and neurologic systems, abnormalities in muscle and mitochondrial function, shifts in metabolism, and gut physiology or gut microbiome disturbances. It is possible that these threads are together entangled as parts of an underlying molecular pathology reflecting a far-reaching homeostatic shift affecting each of these systems. Due to the variability of non-overlapping symptom presentation or precipitating events such as infection or other bodily stresses, the initiation of body-wide pathological cascades with similar outcomes stemming from different causes may be implicated in the condition. Patient stratification to account for this heterogeneity is therefore one important consideration during exploration of potential diagnostic developments.
REVIEW | doi:10.20944/preprints201810.0429.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: Copper; fructose; Kupffer cell (KC); iron; non-alcoholic fatty liver disease (NAFLD); metabolic syndrome; gut microbiota
Online: 18 October 2018 (16:57:06 CEST)
Compelling epidemiologic data support the critical role of dietary fructose in the epidemic of obesity, metabolic syndrome and nonalcoholic fatty liver disease (NAFLD). The metabolic effects of fructose on the development of metabolic syndrome and NAFLD are not completely understood. High fructose intake impairs copper status, and copper-fructose interactions have been well documented in rats. Altered copper-fructose metabolism leads to exacerbated experimental metabolic syndrome and NAFLD. A growing body of evidence has demonstrated that copper levels are low in NAFLD patients. Moreover, hepatic and serum copper levels are inversely correlated with the severity of NAFLD. Thus, high fructose consumption and low copper availability are considered two important risk factors in NAFLD. However, the causal effect of copper-fructose interactions as well as the effects of fructose intake on copper status remain to be evaluated in humans. The aim of this review is to summarize the role of copper-fructose interactions in the pathogenesis of the metabolic syndrome and discuss the potential underlying mechanisms. This review will shed light on the role of copper homeostasis and high fructose intake and point to copper-fructose interactions as novel mechanisms in the fructose induced NAFLD.
REVIEW | doi:10.20944/preprints201809.0597.v1
Subject: Life Sciences, Microbiology Keywords: Prebiotics; Infant Nutrition; Infant formula; Gut microbiota; Lactobacillus; Bifidobacterium; Fructo-oligosaccharides; Galacto-oligosaccharides; Polidextrose; Acidic oligosaccharides.
Online: 30 September 2018 (05:42:39 CEST)
Abstract: Supplementation of infant formula with ingredients potentially able to manage, in a way positive for the host, the gut microbiota of infants, is nowadays widely used by infant food producers. The impact of this class of compounds, named prebiotics, on gut microbiota composition, was initially measured on the enrichment of Bifidobacterium and Lactobacillus spp., but the use of culture-independent analytical techniques has allowed to establish that a larger number of intestinal microorganisms are affected by the ingestion of prebiotics. However, despite a relevant number of scientific publications, actually there is no consensus on the amount of prebiotics to be administered daily, the potentially different actions exerted by prebiotics which differ in biochemical structures, as well as the impact of different percentages of the same prebiotics when used in mixtures and/or combination. This paper is aimed to critically review the available data on the use of prebiotics in infant formula, with special attention paid to identify a link between, the dosage used, the mixture composition and the observed outcomes, keeping in mind the influences in nutrition quality and growth influence.
REVIEW | doi:10.20944/preprints201808.0438.v1
Subject: Life Sciences, Virology Keywords: Enteric Virus, Non-Human Primate, Virome, Macaque, Dysbiosis, Enteritis, Diarrhea, Animal Model, Rotavirus, Calicivirus, Gut Microbiome
Online: 27 August 2018 (00:17:27 CEST)
There is an important role non-human primates (NHP) play in biomedical research. Phylogenetic proximity of any of the NHP species to Homo sapiens assures that much better translatability of research outcomes from model studies involving human diseases can be achieved than from those generated with other pre-clinical systems. Our group and others used during past two decades NHPs in research directed towards viral and autoimmune disorders of the gastrointestinal tract. This review summarizes progress made in the area of enteric viral infections and its applicability to human disease.