ARTICLE | doi:10.20944/preprints201806.0087.v1
Subject: Biology, Entomology Keywords: insulin-signaling; insulin receptor; Aedes aegypti; mosquitoes; insulin; insulin-like peptides; nutrition; hyperinsulinemia; larval-diet; metabolic reserves
Online: 6 June 2018 (11:55:53 CEST)
Mosquitoes have distinct developmental and adult life history, and the vectorial capacity of females has been shown to be affected by the larval nutritional environment. However, little is known about the effect of developmental nutrition on insulin-signaling and nutrients storage. In this study, we used Aedes aegypti, the yellow fever mosquito, to determine whether larval nutrition affects insulin gene expression. We also determined the traits regulated by insulin signaling, such as stored-nutrients levels and fecundity. We raised mosquito larvae on two different diets, containing either high protein or high carbohydrates. Development on a high-carbohydrate diet resulted in several life-history phenotypes indicative of suboptimal conditions, including increased developmental time and decreased fecundity. Additionally, our data showed that insulin transcript levels are affected by a high-carbohydrate diet during development. Females, not males, reared on high-carbohydrate diets had much higher transcript levels of insulin-like peptide 3 (ILP3), a mosquito equivalent of human insulin, and these females more readily stored sugar from the meal into lipids. We also found that AaILP4, not AaILP3, transcript levels were much higher in the males after a sugar meal, suggesting sex-specific differences in insulin-signaling pathway. Our findings suggest a conserved mechanism of carbohydrate-mediated hyperinsulinemia in animals.
ARTICLE | doi:10.20944/preprints201909.0247.v2
Subject: Keywords: obesity; obesity paradox; diabetes; insulin resistance (IR); whole body insulin resistance (WBIR); tissue-specific insulin resistance; muscle insulin resistance (MIR); subcutaneous insulin resistance (s-AIR); visceral adipose insulin resistance (v-AIR); hepatic insulin resistance (HIR); lipid-induced insulin resistance (LIIIR); glycation-induced insulin resistance (GIIIR)
Online: 9 October 2019 (04:21:56 CEST)
Even though it has long been known that diabetes develops in distinctive stages over a long span of time, no comprehensive diabetes development model has been developed yet. Insulin resistance (IR) plays a central role in development of diabetes. A widespread belief regarding IR is that it is a global parameter affecting the whole body simultaneously by impairing merely glucose uptake in tissues. However, the analysis by a new methodology that we have named integrated approach suggests that IR not merely impairs glucose uptake in tissues but also produces tissue-specific metabolic disruptions varying widely from tissue to tissue, and that IR would not necessarily develop simultaneously over the whole body but instead develop first preferentially in the muscle tissue with a relatively low cell turnover and then progress in sequence to the subcutaneous adipose tissue to the visceral adipose tissue to the liver with higher cell turnovers. This is the most important rationale for subdividing IR into four distinct tissue-specific IRs: muscle insulin resistance (MIR), subcutaneous adipose insulin resistance (s-AIR), visceral adipose insulin resistance (v-AIR), and hepatic insulin resistance (HIR). Sequential development of tissue-specific IRs, in the order of MIR, s-AIR, v-AIR, and HIR, producing tissue-specific metabolic disruptions, is nothing but the whole body insulin resistance (WBIR) evolving in four distinctively insulin-resistant stages. Four-stage evolution from rapid weight gain to visceral obesity to rapid weight loss to full-blown diabetic state not only complies well with the natural development history of diabetes, but also resolves most of controversies on diabetes or obesity. Development of the four-stage WBIR evolution model, which also refutes the entrenched notion of the lipid-induced insulin resistance (LIIR) but instead supports the glycation-induced insulin resistance (GIIR) proposed in this study, may possibly be considered a breakthrough in study of diabetes as well as obesity.
REVIEW | doi:10.20944/preprints202103.0401.v1
Subject: Keywords: insulin; insulin receptor; brain insulin resistance; mitochondria; brain; neuron; H2O2; glutamate excitotoxicity.
Online: 15 March 2021 (17:38:24 CET)
Current hypotheses implicate insulin resistance of the brain as a pathogenic factor in the development of Alzheimer’s disease and other dementias, Parkinson’s disease, type 2 diabetes, obesity, major depression, and traumatic brain injury. A variety of genetic, developmental, and metabolic abnormalities that lead to disturbances in the insulin receptor signal transduction may underlie insulin resistance. Insulin receptor substrate proteins are generally considered to be the node in the insulin signaling system that is critically involved in the development of insulin insensitivity during metabolic stress, hyperinsulinemia, and inflammation. Emerging evidence suggests that lower activation of the insulin receptor (IR) is another common, while less discussed, mechanism of insulin resistance in the brain. This review aims to discuss causes behind the diminished activation of IR in neurons, with a focus on the functional relationship between mitochondria and IR during early insulin signaling and the related roles of oxidative stress, mitochondrial hypometabolism, and glutamate excitotoxicity in the development of IR insensitivity to insulin.
REVIEW | doi:10.20944/preprints202103.0372.v1
Subject: Medicine & Pharmacology, Allergology Keywords: insulin; insulin receptor; brain insulin resistance; mitochondria; brain; neuron; H2O2; glutamate excitotoxicity.
Online: 15 March 2021 (11:46:08 CET)
Current hypotheses implicate insulin resistance of the brain as a pathogenic factor in the development of Alzheimer’s disease and other dementias, Parkinson’s disease, type 2 diabetes, obesity, major depression, and traumatic brain injury. A variety of genetic, developmental, and metabolic abnormalities that lead to disturbances in the insulin receptor signal transduction may underlie insulin resistance. Insulin receptor substrate proteins are generally considered to be the node in the insulin signaling system that is critically involved in the development of insulin insensitivity during metabolic stress, hyperinsulinemia, and inflammation. Emerging evidence suggests that lower activation of the insulin receptor (IR) is another common, while less discussed, mechanism of insulin resistance in the brain. This review aims to discuss causes behind the diminished activation of IR in neurons, with a focus on the functional relationship between mitochondria and IR during early insulin signaling and the related roles of oxidative stress, mitochondrial hypometabolism, and glutamate excitotoxicity in the development of IR insensitivity to insulin.
ARTICLE | doi:10.20944/preprints201711.0055.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: diet; dietary protein; dietary fibre; insulin sensitivity assessment; insulin sensitivity; insulin resistance; metabolic syndrome
Online: 8 November 2017 (16:20:47 CET)
Evidence shows that weightloss improves insulin sensitivity but few studies have examined the effect of macronutrient composition independently of weight loss on direct measures of insulin sensitivity. We randomised 89 overweight or obese women to either a standard diet (StdD) that was intended to be low in fat and relatively high in carbohydrate (n=42) or to a relatively high protein (up to 30% of energy), relatively high fibre (>30g/day) diet (HPHFib) (n=47) for 10 weeks. Advice regarding strict adherence to energy intake goals was not given. Insulin sensitivity and secretion was assessed by a novel method - the Dynamic Insulin Sensitivity and Secretion Test (DISST). Although there were significant improvements in body composition and most cardiometabolic risk factors on HPHFib, insulin sensitivity was reduced by 19.3% (95% CI: 31.8, 4.5%; p=0.013) in comparison with StdD. We conclude that the reduction in insulin sensitivity after a diet relatively high in both protein and fibre, despite cardiometabolic improvements, suggests insulin sensitivity may reflect metabolic adaptations to dietary composition for maintenance of glucose homeostasis, rather than impaired metabolism.
ARTICLE | doi:10.20944/preprints202005.0514.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: AKT; D-Pinitol; ghrelin; insulin; insulin resistance; liver; phosphorylation
Online: 31 May 2020 (21:11:01 CEST)
To characterize the metabolic actions of D-Pinitol, a dietary inositol, in male Wistar rats, we analysed its oral pharmacokinetics and its effects on a) the secretion of hormones regulating metabolism (insulin, glucagon, IGF-1, ghrelin, leptin and adiponectin), b) insulin signaling in the liver and c) the expression of glycolytic and neoglucogenesis enzymes. Oral D-Pinitol administration (100 or 500 mg/Kg) resulted in its rapid absorption and distribution to plasma and liver compartments. Its administration reduced insulinemia and HOMA-IR, while maintaining glycaemia thanks to increased glucagon activity. In the liver, D-Pinitol reduced the key glycolytic enzyme pyruvate kinase and decreased the phosphorylation of the enzymes AKT and GSK-3. These observations were associate with an increase in ghrelin concentrations, a known inhibitor of insulin secretion. The profile of D-Pinitol suggests its potential use as a pancreatic protector decreasing insulin secretion through ghrelin upregulation while sustaining glycaemia through liver-based mechanisms of glycolysis control.
ARTICLE | doi:10.20944/preprints202107.0365.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: cannabis; cannabinoid; diabetes; insulin
Online: 16 July 2021 (09:24:11 CEST)
The purpose of the study was to describe and compare the pharmacokinetics of five commercial edible marijuana products, determine the influence of body composition on pharmacokinetics, and, in light of epidemiology suggesting marijuana may offer diabetes protection, explore the influence of edible marijuana on glucose tolerance. Seven regular users of marijuana self-administered five edible products in a randomized crossover design; each product contained 10mg of delta-9-tetrahydrocannabinol (THC). 30-minutes following marijuana ingestion, participants imbibed a 75g glucose beverage. Time-to-peak plasma THC concentration ranged between 35 and 90 minutes; maximal plasma THC concentration (Cmax) ranged between 3.2 and 5.5 ng/mL. Differences between products in plasma THC concentration during the first 20-to-30 minutes were detected (P=0.019). Relations were identified between body composition and pharmacokinetic parameters for some products; however, none of these body composition characteristics were consistently related to pharmacokinetics across all five of the products. Edible marijuana had no effect on oral glucose tolerance compared with a marijuana-free control (Matsuda Index; P>0.395). Commercially available edible marijuana products evoke different plasma THC concentrations shortly after ingestion, but do not appear to influence acute glucose regulation. These data may allow marijuana users to make informed decisions pertaining to rates of edible marijuana ingestion and avoid overdose.
ARTICLE | doi:10.20944/preprints202211.0412.v1
Subject: Life Sciences, Other Keywords: long-acting insulin; detemir; X-ray crystallography; insulin dynamics; Gaussian Network Analysis
Online: 22 November 2022 (08:47:01 CET)
The treatment of insulin-dependent diabetes mellitus is characterized by artificial supplementation of pancreatic β-cell ability to regulate sugar levels in the blood. Even though various insulin analogs are crucial for reasonable glycemic control, understanding the dynamic mechanism of the insulin analogs may help to improve the best-protracted insulin analog to assist people with Type 1 Diabetes (T1D) to live comfortably while maintaining tight glycemic control. Here we present the high-resolution crystal structure of NN304, known as insulin detemir, to 1.7 A resolution at cryogenic temperature. We computationally further investigated our crystal structure's monomeric-dimeric conformation and dynamic profile by comparing it with a previously available detemir structure (PDB ID: 1XDA). Our structure (PDB ID: 8HGZ) obtained at elevated pH provides a distinct alternative dimeric conformation compared to the previous structure, suggesting it might induce an intermediate state in the dissociation pathway of the insulin detemir’s hexamer:dihexamer equilibrium. Combined with orientational cross-correlation analysis by Gaussian Network Model (GNM), this alternate oligomeric conformation offers the distinct cooperative motions of a protracted insulin analog that has not been previously observed.
ARTICLE | doi:10.20944/preprints202212.0297.v3
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: ALS; frontotemporal dementia; insulin; diabetes
Online: 24 January 2023 (10:25:55 CET)
Background. Amyotrophic Lateral Sclerosis (ALS) is a devastating disease involving motor neuron degeneration. The few drugs approved for treatment have at most a marginal benefit, and death usually occurs 2-5 years after diagnosis. Methods. A thorough manual examination of the relevant literature, covering over 35,000 papers. Results. Two major phenomena that are generally not known to clinicians were found. First, insulin signaling is impaired in ALS even in patients not diagnosed with diabetes (DB). Almost all studies that have explicitly tested insulin function in non-DB ALS patients using glucose tolerance tests (18 out of 20, 1964-2022, different groups) have found it to be impaired. Second, there is strong evidence for excessive insulin-independent glucose uptake (IIGU) in ALS. In addition, (i) early/late diabetes are associated with increased/decreased risk, respectively; (ii) insulin-based diabetes drugs are protective in ALS in large retrospective human studies; and (iii) strong animal and human evidence shows that insulin opposes all of the major pathological processes in ALS. Conclusion. Most ALS patients have insulin impairment, yet this is commonly not diagnosed, likely because excessive IIGU normalizes glucose levels. The impairment promotes disease progression. Late diabetes is associated with decreased risk because high glucose levels indicate non-excessive IIGU, and because diabetes drugs are protective. Insulin-based treatment (e.g., GLP1 agonists, insulin) is beneficial and can be disease-modifying in ALS and in frontotemporal dementia variants comorbid with ALS. ALS patients should be routinely tested for insulin function and treated if test results are positive.
ARTICLE | doi:10.20944/preprints202010.0430.v1
Online: 21 October 2020 (10:45:49 CEST)
Literature reported the insulin is an important for the humans and it is secreted in the pancreas and controls, regulates the glucose level. It also controls the mechanism and growth. On decreasing the amount of insulin can caused diabetes, several cancers and other disease. Therefore, there is a need to find promising candidates can binds with insulin and stabilize them. Organic compounds containing hetero atoms have lots of biological potency in different area, therefore, researchers are designing new biological potent compounds. Further, insilico studies attracted the researchers in last one decade mainly to get the drug in less time with a clear strategy. In the present work, authors have designed two types of conjugates, xanthenes with trizole as well benzisoxazole and study their interaction with the insulin using computational methods. The library of compounds was screened through molecules docking in terms of binding energy between the designed compound and the active site of the receptor. Further, their ADME properties are investigated. CMPD19 showed best binding affinity with the insulin and may be considered as oral drug based on the bioactive scores.
ARTICLE | doi:10.20944/preprints202008.0419.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: glucocorticoids; atrophy; obesity; atrogenes; insulin resistance
Online: 20 August 2020 (02:38:54 CEST)
Glucocorticoids promote muscle atrophy by inducing a class of proteins called atrogenes, resulting in reductions in muscle size and strength. In this work, we evaluated whether a mouse model with pre-existing diet-induced obesity had altered glucocorticoid responsiveness. We observed that all animals treated with the synthetic glucocorticoid dexamethasone had reduced strength, but that obesity exacerbated this effect. These changes were concordant with more pronounced reductions in muscle size, particularly in Type II muscle fibers, and potentiated induction of atrogene expression in the obese mice relative to lean mice. Furthermore, we show that the reductions in lean mass do not fully account for the dexamethasone-induced insulin resistance observed in these mice. Together these data suggest that obesity potentiates glucocorticoid-induced muscle atrophy.
REVIEW | doi:10.20944/preprints201707.0024.v1
Subject: Life Sciences, Biochemistry Keywords: insulin; phenolic derivatives; crystallography; powder diffraction
Online: 12 July 2017 (04:11:12 CEST)
Human Insulin (HI) is a well-characterized natural hormone which regulates glycose levels into the blood-stream and is widely used for diabetes treatment. Numerous studies have manifested that despite significant efforts devoted to structural characterization of this molecule and its complexes with organic compounds (ligands), there is still a rich diagram of phase transitions and novel crystalline forms to be discovered. Towards the improvement of drug delivery, identification of new insulin polymorphs from polycrystalline samples, simulating the commercially available drugs, is feasible today via macromolecular X- ray powder diffraction (XRPD). This approach has been developed and is considered as a respectable method, which can be employed in biosciences for various purposes such as observing phase transitions and characterizing bulk pharmaceuticals. An overview of structural studies on human insulin complexes performed over the past decade employing both synchrotron and laboratory sources for XRPD measurements, is reported herein. This review aims to assemble all recent advances in diabetes treatment field in terms of drug formulation, verifying in parallel the efficiency and applicability of protein XRPD for quick and accurate preliminary structural characterization in large scale.
ARTICLE | doi:10.20944/preprints201811.0321.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: Theaflavins; Hepatocyte; Insulin resistance; Insulin signaling pathway; Mitochondrial biogenesis; Peroxisome proliferator-activated receptor coactivator-1 (PGC-1)
Online: 13 November 2018 (15:16:30 CET)
Theaflavins, the characteristic and bioactive polyphenols in black tea, possess the potential improvement effects on insulin resistance-associated metabolic abnormalities including obesity and type 2 diebetes. However, the molecular mechanisms of theaflavins improving insulin sensitivity are still not clear. In this study, we investigated the protective effects and mechanisms of theaflavins on palmitic acid-induced insulin resistance in HepG2 cells. Theaflavins could significantly increase glucose uptake of insulin-resistant cells at noncytotoxic doses. This activity was mediated by upregulating the glucose transporter 4 protein expression, increasing the phosphorylation of IRS-1 at Ser307, and reduced the phosphor-Akt (Ser473) level. Moreover, theaflavins were found to enhance mitochondrial DNA copy number through down-regulate the PGC-1β mRNA level and up-regulate PRC mRNA expression in insulin-resistant HepG2 cells. These results indicated that theaflavins could improve free fatty acid-induced hepatic insulin resistance by promoting mitochondrial biogenesis, and were promising functional food and medicines for insulin resistance-related disorders.
ARTICLE | doi:10.20944/preprints202006.0011.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: diabetes mellitus; insulin resistance; inflammation; biomarkers; atherogenicity
Online: 3 June 2020 (05:41:03 CEST)
Background: Type 2 diabetes mellitus (T2DM) is associated with increased atherogenicity and inflammatory responses, which may be related to increased levels of high mobility group box 1 (HMGB1) and Dickkopf-related protein 1 (DKK1). Objective: The role of HMGB1 and DKK1 in T2DM is examined in association with lipid and insulin profiles. Methods: Serum HMGB1 and DKK1 were measured in T2DM with and without hypertension and compared with controls. Results: HMGB1 and DKK1 are significantly higher in T2DM irrespective of hypertension. T2DM was also accompanied by increased atherogenicity indices. HMGB1 and DKK1 are significantly correlated with HbA1c, glucose, indices of insulin resistance, β-cell function, and glucose toxicity, and different atherogenic indices. A large part of the variance in the β-cell index (30.5%) and glucose toxicity (34.8%) was explained by the combined effects of HMGB1 and DKK1 and hypertension. We found that 18.3% of the variance of the atherogenic index of plasma was explained by HMGB1 and DKK1 levels and that 31.2% was explained by glucose toxicity, HMGB1 and body weight. Conclusion: The higher serum HMGB1 and DKK1 levels in T2DM patients and the associations with atherogenicity indicate that low grade inflammation and disorders in the Wnt pathways are associated with T2DM and that both HMGB1 and DKK1 may contribute to increased atherogenicity in T2DM. Moreover, both biomarkers may cause more deficits in β-cell function and increase glucose toxicity leading to the development of more inflammation and diabetic complications. HMGB1 and the Wnt pathways are new drug targets in the treatment of T2DM.
ARTICLE | doi:10.20944/preprints201807.0527.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: autophagy; huntingtin; insulin signaling; liraglutide; oxidative stress
Online: 27 July 2018 (03:35:44 CEST)
Huntington's disease (HD) is a progressive and fatal neurodegenerative disease caused by CAG repeat expansion in the coding region of huntingtin (HTT) protein. The accumulation of mutant HTT (mHTT) contributes to neurotoxicity by causing autophagy defects and oxidative stress that ultimately lead to neuronal death. Interestingly, epidemiologic studies have demonstrated that the prevalence of type-2 diabetes, a metabolic disease mainly caused by defective insulin signaling, is higher in patients with HD than in healthy controls. Although the precise mechanisms of mHTT-mediated toxicity remain unclear, the blockade of brain insulin signaling may initiate or exacerbate mHTT-induced neurodegeneration. In this study, we used an in vitro HD model to investigate whether neuronal insulin signaling is involved in mHTT-mediated neurotoxicity. Our results demonstrated that mHTT overexpression significantly impairs insulin signaling and causes apoptosis in neuronal cells. However, treatment with liraglutide, a GLP-1 analogue, markedly restores insulin sensitivity and enhances cell viability. This neuroprotective effect may be attributed to the contribution of the upregulated expression of genes associated with endogenous antioxidant pathways to oxidative stress reduction. In addition, liraglutide stimulates autophagy through AMPK activation, which attenuates the accumulation of HTT aggregates within neuronal cells. Our findings collectively suggest that liraglutide can rescue impaired insulin signaling caused by mHTT and that GLP-1 may potentially reduce mHTT-induced neurotoxicity in the pathogenesis of HD.
REVIEW | doi:10.20944/preprints201801.0081.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: insulin resistance; diet; exercise; microbiome; metabolic disorders
Online: 9 January 2018 (10:05:09 CET)
Insulin resistance is a prominent pathophysiologic syndrome in a plethora of metabolic disorders including obesity, prediabetes, type 2 Diabetes Mellitus (Ten et al., 2007), impaired glucose tolerance, dyslipidemia, polycystic ovary syndrome and hypercoagulability (Smith & LeRoith, 2004). It is strongly associated with obstructive sleep apnea, hypoventilation syndrome, pancreatitis, nonalcoholic fatty liver disease, steatohepatitis, cirrhosis, gall bladder disease, multiple cancers (breasts, uterus, cervix prostate, kidney, colon, esophagus, pancreas and liver), stroke, cataracts, coronary heart disease, and hypertension. It is also associated with causation of abnormal menses, infertility, polycystic ovary syndrome, osteoarthritis, phlebitis and other venous diseases. Insulin resistance is thought to be caused by intrinsic and extrinsic factors that contribute to its development. Once present, insulin resistance affects the metabolism, behavior, physical appearance and has lasting effects. This paper will review the latest evidence in development of insulin resistance, its pathogenesis and manifestation and its relation to other conditions. The final aim is to raise awareness of its role on diet, metabolic, genetics and microbiome.
ARTICLE | doi:10.20944/preprints202301.0187.v1
Subject: Life Sciences, Other Keywords: Parkinson’s disease; 6-hydroxydopamine; cognitive deficit; insulin; glutamate
Online: 11 January 2023 (01:42:35 CET)
Cognitive deficit is a frequent non-motor symptom in Parkinson 's disease (PD) with an unclear pathogenesis. Recent research indicates possible involvement of insulin resistance and glutamate excitotoxicity in PD development. We investigated cognitive performance and the brain glutamate and insulin signaling in a rat model of PD induced by bilateral intrastriatal injection of 6-hydroxydopamine (6-OHDA). Cognitive functions were assessed with Passive avoidance (PA) and Morris Water Maze (MWM) tests. The expression of tyrosine hydroxylase (TH) and proteins involved in insulin (IR, pI3K, ERK) and glutamate receptor (AMPAR, NMDAR) signaling was assessed in the hippocampus (HPC), hypothalamus (HPT) and striatum (S) by immunofluorescence, Western blot and ELISA. Three months after 6-OHDA treatment, cognitive deficit was accompanied by decreased AMPAR activity and TH levels (HPC, S), while levels of the proteins involved in insulin signaling remained largely unchanged. Spearman’s rank correlation revealed a strong positive correlation for pAMPAR-PA (S), pNMDAR-pI3K (HPC) and pNMDAR-IR (all regions). Additionally, a positive correlation was found for TH-ERK and TH-pI3K, and a negative one for TH-MWM/errors and pI3K-MWM/time (S). These results suggest a possible association between brain glutamate (but not insulin) signaling dysfunction and cognitive deficit in a rat PD model, detected three months after 6-OHDA treatment.
ARTICLE | doi:10.20944/preprints202210.0299.v1
Subject: Medicine & Pharmacology, Obstetrics & Gynaecology Keywords: PCOS; Gene expression; Insulin resistance; Diabetes; HOMA-IR
Online: 20 October 2022 (08:25:43 CEST)
Background Polycystic ovary syndrome (PCOS) is a common hormonal disorder worldwide among women of reproductive age. It is characterized by endocrine, reproductive, and metabolic abnormalities. Insulin resistance (IR) is one of its most important clinical features, associated with metabolic disorders and increased risk of type 2 diabetes (T2D). This study aimed to explore the whole blood gene expression profiling related to IR in PCOS patients compared to controls. Methods Blood RNA was extracted from 5 PCOS and 5 non-PCOS women with matched age and BMI. Homeostasis model assessment (HOMA-IR) was used to estimate the IR. The expression of IR genes was analyzed by Profiler PCR array. Results Both groups have similar levels of HOMA-IR (p>0.05). However, differential expression levels were observed between them. Fourteen genes were upregulated and 26 genes were downregulated in PCOS samples. Among the upregulated genes (>2 fold-change, p-value<0.05) are ADIPOQ, ADIPOR1, OLR, IGF-1, and APOE. Downregulated genes (>-2 fold-change, p-value<0.05) include HK-2, IRS1, and SERPINE1. These genes are involved in insulin and adipokines signaling, commonly dysregulated in T2D. They are also involved in innate immunity and inflammatory processes and are essential for lipid and carbohydrate metabolism. Conclusion Our finding suggests that despite both groups having no difference in IR level, there are differentially expressed genes involved in the IR pathway.
Subject: Medicine & Pharmacology, Allergology Keywords: central obesity; fetuin-A; lean NAFLD; insulin resistance
Online: 5 July 2021 (12:32:33 CEST)
Patients with lean NAFLD make up an increasing subset of liver diseases. The association between lean NAFLD and feutin-A, which serves as a hepatokine and adipokine, has never been examined. Our study aimed to explore the association of serum fetuin-A among lean and nonlean patients. The study comprised 606 adults from the community, stratified into lean or nonlean (BMI </≥ 24 kg/m2) and NAFLD or non-NAFLD (scoring of ultrasonographic fatty liver indicator, US-FLI ≥ 2/<2). Multivariate logistic regression analyses were performed to estimate the odds ratio of having NAFLD among the tertiles of fetuin-A after adjustment. The least square means were computed by general linear models to estimate marginal means of the serum fetuin-A concentrations in relation to the NAFLD groups. The OR of having NAFLD for the highest versus the lowest tertile of fetuin-A was 2.62 (95% CI: 1.72-3.98; P for trend<0.001). Stratifying by BMI, the OR of having lean NAFLD for the highest versus the lowest tertile of fetuin-A was 2.09 (95% CI: 1.09-3.98; P for trend 0.026), while nonlean NAFLD had no significant association with the fetuin-A gradient after adjustments. Fetuin-A was positively associated with lean NAFLD after adjusting for central obesity and insulin resistance.
ARTICLE | doi:10.20944/preprints202007.0431.v1
Subject: Life Sciences, Other Keywords: Diabetes mellitus; Lamiaceae; glucose uptake; toxicity; insulin resistance
Online: 19 July 2020 (20:01:42 CEST)
The prevalence of diabetes mellitus (DM), considered one of the most common metabolic disorders, has dramatically increased and resulted in higher rate of morbidity and mortality around the world, in the past decade. It is well known that insulin resistance in target tissues and a deficiency in insulin secretion from pancreatic β-cells are the main characteristic of type 2 diabetes. The aim of this study was the bio-evaluation of compounds isolated from three selected plant species; namely, Salvia africana-lutea, Leonotis ocymifolia and Plectranthus madagascariensis, for their glucose uptake ability. Methanolic extracts were produced from the arterial part of each plant. Compounds were identified using different spectroscopic techniques. The glucose uptake ability of each compound was then evaluated in mammalian cells using 2-deoxyglucose-6-phosphate. The cytotoxicity of each compound was established via the MTT assay. Chromatographic purification of the three plant species yielded fifteen pure terpenoids. Compounds 1 (p = 0.0031), 8 (p = 0.0053), and 6 (p = 0.0086), showed a marked increase in glucose uptake, with p values of p=0.0031, p=0.0053 and p=0.0086, respectively. Additionally, 1, 4 and 6 exhibited cytotoxicity toward mammalian tissue with a decrease in cell viability of ~70%, ~68% and ~67%, respectively. The results suggested that several compounds demonstrated a marked increase in glucose uptake while two of the compounds exhibited signs of cytotoxicity. It may, therefore, be suggested that these compounds be considered as potential candidates for novel plant-derived alternative therapies in the treatment of type 2 diabetes.
ARTICLE | doi:10.20944/preprints202004.0463.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: diabetes mellitus; insulin resistance; cytokines; adaptor proteins; CLNK
Online: 25 April 2020 (11:32:48 CEST)
Type 2 diabetes mellitus (T2DM) is an endocrine illness associate with various changes in the immune system and adaptor protein levels. Cytokine dependent hematopoietic cell linker (CLNK) is an adapter protein that regulates immune receptor signaling and acts as a regulator of the receptor signaling of T-cells and natural killer T-cell. The role of CLNK in T2DM is not studied previously. In the present study, serum CLNK level was measured and correlated with some sociodemographic and insulin resistance (IR) parameters. This is achieved by performing measurement of CLNK and insulin parameters (glucose, insulin, and HbA1c in addition to the calculation of the functions of IR (HOMA2IR), insulin sensitivity (HOMA%S), and beta-cell function (HOMA%B)) in 60 T2DM patients and 30 controls. The results indicated a significant increase (p=0.025) in serum CLNK in patients group in comparison with the controls. Multivariate generalized linear model (GLM) analysis revealed no significant effect of age, BMI, and sex on the CLNK level. The results of tests for between-subjects showed that the CLNK affects diagnosis significantly (F=7.445, p=0.008, partial η2 =0.081) and its effect is approximately the same as the effect of insulin (F=8.107, p=0.006, partial η2 =0.087). The correlation study showed a highly significant positive correlation between CLNK and the duration of disease (rho=0.420, p<0.001). It can be concluded that the increase CLNK in T2DM revealing the role of the adaptor proteins level in the nature of disease. Elevation of CLNK level may be used as a predictor for diabetes complications, which needs more investigations.
ARTICLE | doi:10.20944/preprints201910.0270.v1
Subject: Medicine & Pharmacology, Allergology Keywords: apelin; galectin-3; Preeclampsia; insulin resistance; lipid profile
Online: 23 October 2019 (17:31:26 CEST)
Preeclampsia (PE) is a common pregnancy complication. It is associated with high maternal morbidity and mortality rates and intrauterine foetal growth restriction. This condition is characterised by high blood pressure and urinary protein levels. Apelin and galectin-3 (Gal- 3) are peptides involved in the regulation of body fluid homeostasis, inflammation and cardiovascular functions. This study aimed to determine the correlations amongst serum apelin and Gal-3 levels and insulin resistance (IR) in women with PE. Sixty patients with PE and 30 healthy controls participated in this study. The PE group had significantly lower apelin levels (p < 0.01) and higher Gal-3 levels (p < 0.05) than the control group. The PE group had higher serum glucose levels and β-cell functions than the control group. Moreover, patients with PE exhibited dyslipidaemia. Correlation analysis indicated that apelin and Gal-3 levels were not significantly correlated. Moreover, no correlation existed between the apelin levels and any measured parameters of the PE group. In conclusion, the elevations in serum Gal-3 levels with increments in IR-related parameters and lipid profiles reflect the possible contribution of Gal-3 to the harmful effects of IR and dyslipidemia levels on women with PE.
ARTICLE | doi:10.20944/preprints201810.0488.v2
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: diabetes kidney; oxidative stress; inflammation; resveratrol; insulin signaling
Online: 4 January 2019 (11:43:35 CET)
Background and objectives: Diabetes mellitus is a disease of insulin deficiency or its inability of usage by the target tissues leading to impairment of carbohydrate, lipid, and protein metabolisms. Resveratrol, having robust anti-inflammatory and anti-oxidant properties, has a high potential to treat or prevent the pathogenesis of diseases. This study was conducted to reveal the relationship between diabetes-induced oxidative stress and tissue inflammation with changes in main enzymatic antioxidants (cat, sod, gpx, and gst) and the components of the insulin signaling pathway (insulin Rβ, irs-1, pi3k, akt, mtor) in kidney tissues. Additionally, the effects of resveratrol on these parameters were evaluated. Materials and Methods: Male Wistar rats were randomly divided into four groups; (1) control/vehicle; (2) control/20 mg/kg resveratrol; (3) diabetic/vehicle; (4) diabetic/20 mg/kg resveratrol. Gene and protein expressions of antioxidant enzymes and insulin signaling elements were evaluated in renal tissues. Results: Downregulation of antioxidant enzymes’ gene expression in the kidney tissues of diabetic rats was demonstrated and this situation was devoted partially to the reduced gene expression of nfκb. Moreover, the components of renal insulin signaling elements were upregulated at both gene and protein expression levels in diabetic rats, and resveratrol treatment decreased this sensitization towards the control state. Conclusion: Resveratrol partially improved diabetes-induced renal oxidative stress and inflammation due to healing action on renal antioxidant enzymes and insulin signaling pathway components.
REVIEW | doi:10.20944/preprints202005.0293.v1
Subject: Life Sciences, Cell & Developmental Biology Keywords: Insulin-like growth factor-1; Insulin-like growth factor-1 receptor; microgravity; osteoblasts; osteocytes; osteoclasts; IGF-1; IGF1R; rIGF-1
Online: 18 May 2020 (03:31:16 CEST)
Astronauts at are risk of losing 1.0 – 1.5% of their bone mass for every month they spend in space despite their adherence to high impact exercise training programs designed to preserve the musculoskeletal system. This article reviews the basics of bone formation and resorption and details how exposure to microgravity or simulated microgravity affects the structure and function of osteoblasts, osteocytes, osteoclasts, and their mesenchymal and hematologic stem cell precursors. It details the critical roles that insulin-like growth facor-1 and its receptor IGFR1 play in maintaining bone homeostasis and how exposure of bone cells to microgravity affects the function of these growth factors. Lastly, it discusses the potential of tumor necrosis factor-related apoptosis-inducing ligand, syncytin-A, and sclerostin inhibitors and recombinant IGF-1 as a bone-saving treatment for astronauts in space and during their colonization of the Moon.
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/preprints202101.0004.v1
Subject: Life Sciences, Biochemistry Keywords: shipyard welders; PM2.5 metal components; urinary metals; insulin resistance
Online: 4 January 2021 (08:38:23 CET)
Certain studies have reported various insulin resistance responses to ambient heavy metal pollution, but few have reported such responses to occupational heavy metal pollution. Even fewer have demonstrated a relationship between mixture effects of heavy metals and insulin resistance in welding workers. Overall, we recruited 53 welders and 48 administrative staff from a shipyard located in northern Taiwan. Personal exposure to heavy metals was monitored for PM2.5 and urine. Blood samples from each participant were collected from the antecubital vein after fasting. Urine samples from each participant were collected in the same period as blood samples. The geometric mean levels for chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), and cadmium (Cd) in the PM2.5 of the personal breathing zone and urinary Mn of welders were significantly higher than those in administrative staffs. Ambient Cr, Co, Ni, and Cu levels in the PM2.5 and urinary Cd were positively related to HOMA2-IR after adjusting for personal covariates (PM2.5-Cr: β=0.036, 95%C.I.: 0.002 to 0.070; PM2.5-Co: β=0.040, 95%C.I.: 0.002 to 0.077; PM2.5-Ni: β=0.054, 95%C.I.: 0.013 to 0.094; PM2.5-Cu: β=0.049, 95%C.I.: 0.010 to 0.088; U-Cd: β=0.209, 95%C.I.: 0.052 to 0.366, respectively). Our findings indicated the PM2.5 metal components and urinary metals were associated with increased insulin resistance in shipyard welders.
ARTICLE | doi:10.20944/preprints202007.0552.v1
Subject: Keywords: Insulin lispro; BPro28-BLys29 Exchange; Interfacial biophysics; Structural analysis;
Online: 23 July 2020 (11:45:01 CEST)
Insulin lispro was the first fast acting insulin analogue to obtain regulatory approval for therapeutic use. This article puts forward a novel biophysical mechanism where the net impact of the simple B28Pro-B29Lys exchange from regular insulin to insulin lispro is the establishment of a novel set of interfacial electrostatic interactions between Lys28 of insulin lispro and Asp12 of insulin receptor (IR). In addition, a set of structural analysis was presented in this article to further strengthen the binding of insulin lispro to IR, where two polar amino acid residues (Gln51 and Asn74 of insulin lispro) were put forward as two potential targets for site-directed mutagenesis of insulin lispro at its binding interface with IR.
ARTICLE | doi:10.20944/preprints201807.0065.v1
Subject: Life Sciences, Endocrinology & Metabolomics Keywords: hypothalamus; insulin resistance; inflammation; docosahexaenoic acid; PI3K inhibitor; AKT
Online: 4 July 2018 (09:58:03 CEST)
Saturated fatty acids are implicated in the development of metabolic diseases, including obesity and type 2 diabetes. There is evidence, however, that polyunsaturated fatty acids can counteract the pathogenic effects of saturated fatty acids. To gain insight into the early molecular mechanisms by which fatty acids influence hypothalamic inflammation and insulin resistance, we performed time-course experiments in a hypothalamic cell line, using different durations of treatment with the saturated fatty acid palmitate, and the omega-3 polyunsaturated fatty acid, docosahexaenoic acid (DHA). Western blot analysis revealed that palmitate elevated the protein levels of phospho(p)AKT in a time-dependent manner. This effect seems involved in the pathogenicity of palmitate, as temporary inhibition of the PI3K/AKT pathway by selective PI3K inhibitors prevented palmitate-induced insulin resistance. Similarly to palmitate, DHA also increased levels of pAKT, but to a weaker extent. Co-administration of DHA with palmitate decreased pAKT close to the basal level after 8 h, and prevented palmitate-induced insulin resistance after 12 h. Measurement of the inflammatory markers pJNK and pNFκB-p65 revealed tonic elevation of both markers in the presence of palmitate alone. DHA alone transiently induced elevation of pJNK, returning to basal levels by 12 h treatment. Co-administration of DHA with palmitate prevented palmitate-induced inflammation after 12 h, but not at earlier time points.
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/preprints201704.0078.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: Ochratoxin A, insulin, glucagon, glucose, rat plasma, pathology, immunohistochemistry
Online: 13 April 2017 (11:46:19 CEST)
In this study, diabetogenic effects of long term Ochratoxin A (OTA) administration in rats were investigated and its role in the etiology of diabetes mellitus (DM) was examined utilizing 42 female Wistar rats for these purposes. The rats were divided into 3 different study and control groups according to the duration of the OTA administration. Rats received 45 μg OTA daily in their feed for 6, 9 and 24 weeks study groups. Three control groups without any treatment were also used in the same periods. Blood and pancreatic tissue samples were collected during the necropsy at the end of 6, 9 and 24 weeks. Plasma values of insulin, glucagon and glucose in study and control groups were determined. Pancreatic lesions were evaluated by histopathological examination; then insulin and glucagon expression in these lesions were determined by immunohistochemical methods. Statistically significant decrease in insulin levels in contrast to increases in glucagon and glucose levels in blood were observed. Slight degeneration in Langerhans islet cells were observed at the histopathological examination in all OTA treated groups. Immunohistochemistry of pancreatic tissue revealed decreased insulin and increased glucagon expression. This study demonstrated that OTA may cause pancreatic damage in Langerhans islet and predispose rats to DM.
REVIEW | doi:10.20944/preprints202205.0100.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: type 2 diabetes; glycemic control; insulin resistance; nutrients; umbrella review
Online: 9 May 2022 (05:05:33 CEST)
Background: Nutrient supplements are widely used for type 2 diabetes (T2D) yet evidence-based guidance for clinicians is lacking. Methods: We searched the four electronic databases from November 2015–December 2021. The most recent, most comprehensive, high-ranked systematic reviews, meta-analyses and/or umbrella reviews of randomised controlled trials in adults with T2D were included. Data were extracted on study characteristics, aggregate outcome measures per group (glycemic control, measures of insulin sensitivity and secretion), adverse events, and GRADE assessments. Quality was assessed using AMSTAR-2. Results: Twelve meta-analyses and one umbrella review were included. There was very low certainty evidence that chromium, Vitamin C and omega-3 polyunsaturated fatty acids (-3 PUFAs) were superior to placebo for the primary outcome of HbA1c (MD -0.54%, -0.54% and ES -0.27 respectively). Probiotics were superior to placebo for HbA1c (WMD -0.43%). There was very low certainty evidence that Vitamin D was superior to placebo for lowering HbA1c in trials of <6 months (MD -0.17%). Magnesium, zinc, Vitamin C, probiotics and polyphenols were superior to placebo for FBG. Vitamin D was superior to placebo for insulin resistance. Data on safety was limited. Conclusions: Future research should identify who may benefit from nutrient supplementation, safety, and optimal regimens and formulations.
ARTICLE | doi:10.20944/preprints202112.0110.v2
Subject: Medicine & Pharmacology, Nutrition Keywords: BTBR; ob/ob; type-2 diabetes; flavanol; insulin; beta cell
Online: 31 January 2022 (18:09:34 CET)
Type 2 diabetes (T2D) is characterized by hyperglycemia and insulin resistance. Cocoa may slow T2D development and progression. This study employed male and female BTBR.Cg-Lepob/ob/WiscJ and wild type (WT) controls to assess the potential for cocoa to ameliorate progressive T2D and compare responses between sexes. Mice received diet without (WT, ob/ob) or with cocoa extract (ob/ob + c) for 10 weeks. Glucose and insulin tolerance tests (GTT/ITT) were conducted at weeks 1, 5 and 2, 6, respectively. Cocoa provided mild non-significant protection against weight gain vs. ob/ob control in males but not females. Male ob/ob + c had increasing fasting glucose at weeks 1 and 5 GTTs, with significantly higher levels of fasting glucose than ob/ob control at week 5. This was not seen in females. Cocoa protected against elevated 4-hour fasting glucose in week 2, but not week 6, ITTs. Cocoa partly suppressed hyperinsulinemia in males but significantly amplified it in females and protected against loss of beta cell area in females only. The mechanisms of these sex-specific effects remain to be elucidated. This study informs additional experiments with larger sample sizes and demonstrates that sex differences must be considered when designing dietary interventions for T2D.
ARTICLE | doi:10.20944/preprints202004.0442.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: nutrition status; muscle strength; diabetes; handgrip; insulin resistance; functional tests
Online: 24 April 2020 (13:52:32 CEST)
Background and Aims: We aimed to investigate cross-sectional relationships of relative handgrip strength (RHGS) with presence of diabetes and hypertension in a community setting. Methods and Results: Between 2016 and 2018, we enrolled 601 consecutive women with an average age of 70.7 ± 6.9 years (mean ± SD). Nutritional status was evaluated by the Mini Nutritional Assessment (MNA) score. Muscular strength and level of fitness were assessed by handgrip strength (HGS) and other standardized physical functional tests. The majority of participants were overweight or obese (80% with BMI > 25). Prevalence of diabetes and hypertension was 13 and 60%, respectively. Participants in the lowest quartile of HGS adjusted for BMI (RHGS) had significantly higher prevalence of diabetes and hypertension compared with those in the lower quartile (20.7 vs. 5.3% and 49.3 vs. 39.3%, respectively, p < 0.01 for both), whereas differences in nutritional status were not observed. Likelihood of having diabetes was significantly reduced in women with higher RHGS values (OR 0.77; 0.59–0.86 CI95%; p=0.002), independently of age, abdominal adiposity and presence of hypertension. RHGS was positively correlated with most of the physical functional tests performed. Conclusion: RHGS is an easy-to-obtain and inexpensive measure of muscular strength, independently associated with presence of diabetes in overweight elderly women. Prospective studies are required to assess its predictive value in individuals at risk of new onset or progression of diabetes.
ARTICLE | doi:10.20944/preprints201608.0052.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: acinar cells; PLP; amylase; insulin secretion; FACS; viability; PDX-1
Online: 5 August 2016 (08:49:33 CEST)
Aims: To study the effects of pyridoxal phosphate (PLP) on oxidative stress in isolated pancreatic acinar cells. We have previously shown that PLP has cytoprotective and insulinotropic effects on mice islet cells in vivo and in vitro studies. Main methods: Acinar cells were isolated from three months old WNIN male rats and were cultured in vitro for a period of 24 h in CO2 incubator. Later the cells were divided into four groups as untreated (group 1), H2O2 treatment (group 2), PLP treatment (group 3) and PLP followed by H2O2 treatment (group 4). Cell viability was confirmed using MTT assays, oxidative stress levels were measured with ROS assay, change in different protein levels were recorded by flow cytometry. The acinar cells insulin secretion assay was performed with ELISA. The amylase protein expression was assessed using confocal microscopy. Key findings: The cell viability of acinar cell in group 1 was considered as 100%, while in group 2 it was reduced to 82% due to H2O2 effect, and in group 3 (99.8%) and group 4 (99.5%) were near to group 1 due to the cytoprotective effect of PLP. The ROS levels were increased by 1.47 folds in group 2, while PLP decreased to 1.02 fold in group 4, which was comparable with the changes in group 1. Beneficial effects of PLP were also observed from the increased expression levels of acinar cells are amylase -2.01, neurogenin-3-9.51, PDX-1- 23.6 and insulin-13.5 in group 3 compared to group 1. The specificity of PLP’s response was confirmed by amino oxy acetic acid (AOAA), a specific PLP inhibitor. The increased amylase protein localization with PLP was confirmed by confocal microscopy. Insulin secretion efficiency of acinar cells was observed to be 6.13 folds higher at basal and 24.63 fold higher at stimulated levels in group3 compared to group1. Significance: Our results advocate the antioxidant and cytoprotective effects of PLP on the pancreatic acinar cell along with increased pancreatic marker expressions of amylase,PDX-1, neurogenin-3 and insulin proteins.
REVIEW | doi:10.20944/preprints201907.0265.v2
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: Aging; Alzheimer’s disease; brain insulin resistance; db/db diabetic mouse model; diabetic cognopathy; insulin resistance; metabolic syndrome; mixed dementia; obesity; type 2 diabetes mellitus
Online: 9 September 2019 (06:12:15 CEST)
Type 2 diabetes mellitus (T2DM) and late-onset Alzheimer’s disease-dementia (LOAD) are increasing in global prevalence and current predictions indicate they will only increase over the coming decades. These increases may be a result of the concurrent increases of obesity and aging. T2DM is associated with cognitive impairments associated with metabolic factors and increases the cellular vulnerability to develop the age-related increased risk of LOAD. This review addresses possible mechanisms due to obesity, aging, multiple intersections between T2DM and LOAD and mechanisms for the continuum of progression. Multiple ultrastructural images in female diabetic db/db models are utilized to demonstrate marked cellular remodeling changes of mural and glia cells and provide for the discussion of functional changes in T2DM. Throughout this review multiple endeavors to demonstrate how T2DM increases the vulnerability of the brain’s neurovascular unit (NVU), neuroglia and neurons are presented. Five major intersecting links are considered: i. aging (chronic age-related diseases); ii. metabolic (hyperglycemia - advanced glycation end-products and its receptor (AGE/RAGE) interactions and hyperinsulinemia – insulin resistance (a linking linchpin); iii. oxidative stress (reactive oxygen-nitrogen species); iv. inflammation (peripheral macrophage and central brain microglia); v. vascular (macrovascular accelerated atherosclerosis - vascular stiffening and microvascular NVU/neuroglial remodeling) with resulting impaired cerebral blood flow.
REVIEW | doi:10.20944/preprints202301.0012.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: Insulin Resistance; Zinc supplementation; Oxidative stress; Inflammation; Gut microbiome; Hepatic lipophagy
Online: 3 January 2023 (07:35:39 CET)
Insulin signaling plays a crucial role in cellular uptake of glucose and different metabolic pathways. Impairment in cellular insulin sensitivity due to various molecular pathways leads to Insulin resistance (IR) as well as fatty liver. In this review, mechanisms by which zinc involved in decreasing IR are described, focusing on oxidative stress, inflammation, immune system, gut flora and hepatic lipophagy. This study reviews the cause of IR and highlights the role of zinc in mechanisms diminishing IR and fatty liver.
ARTICLE | doi:10.20944/preprints202012.0759.v1
Subject: Medicine & Pharmacology, Other Keywords: adolescents; cardiometabolic risk factors; insulin resistance; abdominal obesity; lifestyle; nutritional habits
Online: 30 December 2020 (15:16:17 CET)
The prevalence of cardiometabolic risk factors has increased in Slovakian adolescents as a result of serious lifestyle changes. This cross-sectional study aimed to assess the prevalence of insulin resistance (IR) and the associations with cardiometabolic and selected lifestyle risk factors in a sample of Slovak adolescents. In total, 2,629 adolescents (45.8% males) aged between 14 and 18 years were examined in the study. Anthropometric parameters, blood pressure, and resting heart rate were measured, fasting venous blood samples were analysed, and HOMA-IR was calculated. The mean HOMA-IR was 2.45±1.91 without a significant intersexual difference. IR (cut-off point for HOMA-IR=3.16) was detected in 18.6% of adolescents (19.8% males, 17.6% females). IR was strongly associated with overweight/obesity (especially central) and with almost all monitored cardiometabolic factors, except for TC and systolic BP in females. The multivariate model selected variables such as low level of physical fitness, insufficient physical activity, breakfast skipping, a small number of daily meals, frequent consumption of sweetened beverages, and low educational level of fathers as the significant risk factors of IR in adolescents. Recognizing the main lifestyle risk factors and early IR identification is important in terms of the performance of preventive strategies. Weight reduction, regular physical activity, and healthy eating habits can improve insulin sensitivity and decrease the incidence of metabolic syndrome, type 2 diabetes, and CVD in adulthood.
REVIEW | doi:10.20944/preprints202007.0432.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: glucose regulated protein (GRP) 94; insulin-like growth factor; obligate chaperone
Online: 19 July 2020 (20:06:53 CEST)
Mammals have two insulin-like growth factors (IGF) that are key mediators of somatic growth, of tissue differentiation and cellular responses to stress. Thus, the mechanisms that regulate the bioavailability of IGFs are important in both normal and aberrant development. IGF-I levels are primarily controlled via the growth hormone-IGF axis, in response to nutritional status, and also reflect metabolic diseases and cancer. One mechanism that controls IGF bioavailablity is the binding of circulating IGF to a number of binding proteins that keep IGF in a stable, but receptor non-binding state. But even before IGF is released from the cells that produce it, it undergoes an obligatory association with a ubiquitous chaperone protein, GRP94. This binding is required for secretion of a properly folded, mature IGF. This chapter reviews the known aspects of the interaction and highlights the specificity issues yet to be determined. The IGF-GRP94 interaction provides a potential novel mechanism of idiopathic short stature, involving the obligatory chaperone and not just IGF gene expression. It also provides a novel target for cancer treatment, as GRP94 activity can be either inhibited or enhanced.
REVIEW | doi:10.20944/preprints202007.0301.v1
Subject: Biology, Physiology Keywords: Adipose tissue; inflammation; insulin resistance; immunometabolism; macrophages; type-2 diabetes; T2D
Online: 14 July 2020 (11:25:48 CEST)
Inflammation plays a key role in the development and progression of type-2 diabetes (T2D), a disease characterised by peripheral insulin resistance and systemic glucolipotoxicity. Visceral adipose tissue (AT) is the main source of inflammation early in disease course. Macrophages are innate immune cells that populate all peripheral tissues, including AT. Dysregulated AT macrophage (ATM) responses to microenvironmental changes are at the root of aberrant inflammation and development of insulin resistance, locally and systemically. The inflammatory activation of macrophages is regulated at multiple levels: cell surface receptor stimulation, intracellular signalling, transcriptionally and metabolically. This review will cover the main mechanisms involved in AT inflammation and insulin resistance in T2D. First, we will describe the physiological and pathological changes in AT that lead to inflammation and insu- lin resistance. We will next focus on the transcriptional and metabolic mechanisms described that lead to the activation of ATMs. We will discuss more novel metabolic mechanisms that influence macrophage polarisation in other disease or tissues contexts that may be relevant to future work in insulin resistance and T2D.
ARTICLE | doi:10.20944/preprints202004.0109.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: insulin-resistance; hyperlipidemia; non alcoholic fatty liver disease (NAFLD); OCTN1; OCTN2
Online: 8 April 2020 (03:22:50 CEST)
Hyperlipidemia and insulin-resistance are often associated with Non Alcoholic Fatty Liver Disease (NAFLD) thereby representing a true issue worldwide, due to increased risk of developing cardiovascular and systemic disorders. Although clear evidence suggests that circulating fatty acids contribute in pathophysiological mechanisms underlying NAFLD and hyperlipidemia, further studies are required for better identify potential beneficial approaches for counteracting such a disease state. Recently, several artichoke extracts have been used for both reducing hyperlipidemia, insulin-resistance and NAFLD, though the mechanism is unclear. Here we used a wild type of Cynara Cardunculus extract (CyC), rich in sesquiterpens and antioxidant active ingredients, in rats fed and High Fat Diet (HFD) compared to Normal Fat Diet (NFD). In particular, in rats fed HFD for four consecutive weeks, we found a significant increase of serum cholesterol, triglyceride and serum glucose. This effect was accompanied by increased body weight and by histopathological features of liver steatosis. The alterations of metabolic parameters found in HFD were antagonised dose-dependently by daily oral supplementation of rats with CyC 10 and 20 mg/Kg over 4 weeks, an effect associated to significant improvement of liver steatosis. The effect of CyC (20 mg/Kg) was also associated to enhanced expression of both OCTN1 and OCTN2 carnitine-linked transporters. Thus, present data suggest a contribution of carnitine system in the protective effect of CyC in diet-induced hyperlipidemia, insulin-resistance and NAFLD.
REVIEW | doi:10.20944/preprints202002.0098.v1
Subject: Life Sciences, Cell & Developmental Biology Keywords: Type 2 diabetes; insulin target tissues; iPSCs; genetic factors; disease modeling
Online: 7 February 2020 (11:45:04 CET)
In this review, we discuss the insulin resistance (IR) and its development in the insulin target tissues that leads to diabetes. Also, we highlight the use of induced pluripotent stem cells (iPSCs) to understand the mechanisms underlying the development of IR. IR is associated with several metabolic disorders, including type 2 diabetes (T2D). The development of IR in insulin target tissues involves genetic and acquired factors. Persons at genetic risk for T2D tend to develop IR several years before glucose intolerance. Although there are currently several mouse models for both IR and T2D that had provided a lot of information about the disease, these models cannot recapitulate all the aspects of this complex disease as seen in each individual. Patient-specific iPSCs can overcome the hurdles faced with the classical mouse models for studying IR. iPSC technology can generate cells genetically identical to IR individuals, which can help in distinguishing between genetic and acquired defects in insulin sensitivity. Combining the technologies of the genome editing and iPSCs may provide important information about the inherited factors underlying the development of different forms of IR. Further studies are required to fill the gaps in understanding the pathogenesis of IR and diabetes.
REVIEW | doi:10.20944/preprints202001.0063.v1
Subject: Life Sciences, Cell & Developmental Biology Keywords: hPSCs; hyperglycemia; insulin-secreting cells; β-cell precursors; pancreatic islets; transplantation.
Online: 8 January 2020 (05:30:34 CET)
Diabetes mellitus (DM) is one of the most prevalent metabolic disorders. In order to replace the function of the destroyed pancreatic beta cells in diabetes, islet transplantation is the widely practiced treatment; however, it has several limitations. As an alternative approach, human pluripotent stem cells (hPSCs) can provide an unlimited source of pancreatic cells that have the ability to secrete insulin in response to high blood glucose level. However, determination of the appropriate pancreatic lineage candidate for the purpose of cell therapy for treatment of diabetes is still debated upon. While hPSC-derived beta cells are perceived as the ultimate candidate, the efficiency needs further improvement in order to obtain a sufficient number of glucose responsive β-cells for transplantation therapy. On the other hand, hPSC-derived pancreatic progenitors can be efficiently generated in vitro and can further mature into glucose responsive beta cells in vivo after transplantation. Herein, we discuss the advantages and predicted challenges associated with the use of each of the two pancreatic lineage products for diabetes cell therapy. Furthermore, we address co-generation of functionally relevant islet cell subpopulations and structural properties contributing to glucose responsiveness of beta cells, as well as the available encapsulation technology for these cells.
REVIEW | doi:10.20944/preprints201905.0328.v1
Subject: Medicine & Pharmacology, Other Keywords: adiponectin; diagnosis; HIV; insulin; non-amplification nucleic acid detection; ultrasensitive ELISA
Online: 28 May 2019 (10:18:41 CEST)
For the diagnosis of disease, the ability to quantitatively detect trace amounts of the causal proteins from bacteria/viruses as biomarkers in patient specimens is highly desirable. Here we introduce a simple, rapid, and colorimetric assay as a de novo, ultrasensitive detection method. This ultrasensitive assay consists of sandwich enzyme-linked immunosorbent assay (ELISA) and thionicotinamide-adenine dinucleotide (thio-NAD) cycling, forming an ultrasensitive ELISA, in which the signal substrate (i.e., thio-NADH) accumulates in a triangular manner, and the accumulated thio-NADH is measured at its maximum absorption wavelength of 400 nm. We have successfully achieved a limit of detection of ca. 10–18 moles/assay for a target protein. As an example of infectious disease detection, HIV-1 p24 could be measured at 0.0065 IU/assay (i.e., 10−18 moles/assay), and as a marker for a lifestyle-related disease, adiponectin could be detected at 2.3 × 10−19 moles/assay. In particular, despite the long-held belief that the trace amounts of adiponectin in urine can only be detected using a radioisotope, our ultrasensitive ELISA was able to detect urinary adiponectin. This method is highly versatile, because simply changing the antibody enables the detection of various proteins. This assay system requires only the measurement of absorbance, thus it requires equipment that is easily obtained by medical facilities, which facilitates diagnosis in hospitals and clinics. Moreover, we describe an expansion of our ultrasensitive ELISA to a non-amplification nucleic acid detection method for nucleic acids using hybridization. These de novo methods will enable simple, rapid, and accurate diagnosis.
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.
ARTICLE | doi:10.20944/preprints202212.0378.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: Gestational diabetes mellitus; Insulin resistance; Microbiome; Metabolome; Database; Differential abundance; Correlation; Pathways
Online: 21 December 2022 (02:53:39 CET)
Pregnancy is a dynamic state with multiple metabolic changes occurring including insulin resistance. Gestational diabetes mellitus (GDM), a form of diabetes that appears during pregnancy, develops if metabolic aberrations occur, in particular, in normal pregnancy-induced insulin resistance. Multi-omics is a powerful approach for uncovering the mechanisms driving metabolic change in different physiologic and pathologic states. A recent study demonstrated that the gestational gut microbiome mediates pregnancy metabolic adaptations through effects on gut indoleamine-2,3 dioxygenase 1 activity and the production of kynurenine. Using the dataset generated from this highly controlled study, we performed a comprehensive analysis of the pregnancy-specific physiological and metabolic profiles, 16S rRNA microbiome, and plasma untargeted LC-MS metabolome data. To facilitate the utilization of these analysis results by other researchers, we developed MOMMI-MP, a database that provides an easy-to-use platform to browse and search differential abundant microbial taxa and metabolites, and to examine metabolic pathways. The datasets consist of data collected from 3 genetically diverse strains of mice (C57BL/6J, CD1, and NIH-Swiss) over 6 time points during the gestational (days 0, 10, 15, and 19 during gestation) and postpartum (days 3 and 20 after delivery) states, totaling 180 samples for each strain. The computational results are presented in various tables and plots, and organized in MOMMI-MP to empower exploratory analyses by other researchers. In conclusion, MOMMI-MP is a resource to facilitate the investigation of novel mechanisms governing metabolic changes during pregnancy.
REVIEW | doi:10.20944/preprints202212.0276.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: Biguanides; Antihyperglycemic agents; Liver alpha-cell axis; gluconeogenesis; Protein metabolism; insulin sensitivity
Online: 15 December 2022 (08:37:28 CET)
Metformin, the treatment of first choice in type 2 diabetes (T2D), is known to mainly act by decreasing endogenous glucose production (EGP) in the liver. Paradoxically, in the last decade several reports documented increased EGP after metformin treatment. This increase, was often attributed to pronounced rises in glucagon, consistent with counter-regulatory response to the glucose lowering effect of metformin. However, considering that hyperglucagonemia, but not hypoinsulinemia, is a main driver of EGP in T2D, increased EGP should have been a common finding. This observation, together with the finding that metformin antagonizes glucagon effects on energy expenditure and protein synthesis, concurrently to its effects on EGP and the emerging evidences demonstrating increased branched chain and gluconeogenic amino acids in response to metformin treatment may points to a liver alpha-cell skeletal muscle cross talk similar to that observed in the liver-alpha cell axis. Here, we provide a mechanistic perspective to this latter possibility, based on mechanistic studies of metformin’s transcriptional targets; retaining thus its glucagon antagonistic and presumably anti-gluconeogenic effects on liver and attributing the increase in EGP to renal gluconeogenesis. We finally discuss how increased EGP might reflect an adverse response to metformin treatment, providing support from clinical and epidemiological data.
ARTICLE | doi:10.20944/preprints202202.0012.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: Human Insulin, Amyloid Fibrils; Protein aggregation; Amorphous aggregates; Aromatic Compounds; Polyphenol; Pyrogallol
Online: 1 February 2022 (12:46:35 CET)
One of the major problems caused by repeated subcutaneous insulin injections in diabetic patients is insulin amyloidosis. Understanding the molecular mechanism of amyloid fibril formation of insulin and finding effective compounds to its inhibit or eliminate is very important and extensive research has been done on it. In this study, the anti-amyloidogenic and destabilizing effects of the pyrogallol, as a phenolic compound, on human insulin protein were investigated by CR absorbance, ThT and ANS fluorescence, FTIR spectroscopy and atomic force microscopy. According to the obtained results, the formation of amyloid fibrils at pH 2.0 and 50 °C was confirmed by CR, ThT, ANS, FTIR assays. Microscopic images also showed the twisted and long structures of amyloid fibrils. Simultaneous incubation of the protein with pyrogallol at different concentrations reduced the intensities of CR, ThT and ANS in a dose-dependent manner and no trace of fibrillar structures was observed in the microscopic images. FTIR spectroscopy also showed that the position of amide I band in the spectrum of samples containing pyrogallol was shifted. Based on the findings in this study, it can be concluded that pyrogallol can be effective in preventing and suppressing human insulin amyloid fibrils.
REVIEW | doi:10.20944/preprints202012.0822.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: Sarcopenia; Non-alcoholic Fatty Liver Disease; Obesity, Insulin Resistance; Prevalence; Metabolic Diseases
Online: 31 December 2020 (15:34:29 CET)
Non-alcoholic fatty liver disease (NAFLD) continues to rise and has become the most common cause of chronic liver disease among all ages and ethnicities. Metabolic disorders such as obesity and insulin resistance are closely associated with sarcopenia and NAFLD. Sarcopenic obesity is a clinical disorder characterized by the simultaneous loss of skeletal muscle and gain of adipose tissue. It is associated with worse outcomes in individuals with NAFLD. It is projected that NAFLD and sarcopenia will rise as the prevalence of obesity continues to increase at an unparallel rate. Recently, sarcopenia and sarcopenic obesity have gained considerable interest, but we still lack a well-defined definition and a management approach. Therefore, it is imperative to continue shining the light on this topic and better understand the underlying mechanism as well as treatment options. In this review article, we aimed to address the pathophysiology, impact, and outcomes of sarcopenic obesity on NAFLD.
ARTICLE | doi:10.20944/preprints202005.0127.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: nonalcoholic fatty liver disease; nonalcoholic steatohepatitis; liver fibrosis; amino acids; insulin resistance
Online: 7 May 2020 (13:29:39 CEST)
Altered amino acid levels have been found in nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). However, it is not clear whether this alteration is due to altered hepatic metabolism or insulin resistance. The aim of this study was to clarify the association among amino acid levels, fatty liver, and liver fibrosis while eliminating the influence of insulin resistance. NAFLD and liver fibrosis were diagnosed using transient elastography and subjects were divided in three groups: normal, NAFLD, and liver fibrosis. To exclude the influence of insulin resistance, the subjects were matched using the homeostasis model assessment of insulin resistance (HOMA-IR). The amino acid serum levels were compared among the groups. Of 731 enrolled subjects, 251 and 33 were diagnosed with NAFLD and liver fibrosis. Although significant differences were observed among the groups in the serum levels of most amino acids, all but those of glutamate and glycine disappeared after matching for HOMA-IR. The multivariate logistic regression revealed that glutamate, glycine, and HOMA-IR were independent risk factors for liver fibrosis. The altered serum levels of most amino acids were associated with insulin resistance, while the increase in glutamate and the decrease in glycine levels were strongly associated not only with insulin resistance, but also with altered liver metabolism in patients with liver fibrosis.
ARTICLE | doi:10.20944/preprints201804.0100.v1
Subject: Medicine & Pharmacology, Sport Sciences & Therapy Keywords: Cd36; mass spectrometry; NAFLD; anti-lypase activity; anti-amylase activity; insulin resistance
Online: 9 April 2018 (08:28:02 CEST)
Rhizophora mangle L. is a well-known medicinal plant found in mangroves worldwide used to treatment diabetes. This study evaluated the chemical composition of the acetonic extract from Rhizophora mangle barks (AERM), by HPLC-PDA and FIA-ESI-IT-MS/MS and the effects on high-fat diet induced obesity in mice and its mechanism of action by gene expression of inflammatory markers (Pparg, Ppara, Srebf1, Cd36, Tnf, Ccl2, Lep, Il10, Il6, Fasn, 18s). High-fat diet fed mice during 12 weeks was used as model of obesity and associated alterations. The results were very satisfactory, the extract, rich in polyphenolic compounds, flavonoids and phenolic acids, displayed intense antioxidant activity in vitro (608 µmol Trolox/g), and showed excellent activity against non-alcoholic fatty liver disease (NAFLD) and reverse insulin resistance in a model of diet-induced obesity. We can registered a modulatory effect of AERM in liver PPAR-γ mRNA expression associated to an important inhibition of CD36 mRNA expression suggesting that AERM induces the down regulation of CD36 mRNA via PPAR-gamma inhibition. These results support the traditional knowledge about the use of R. mangle for the treatment of type 2 diabetes and reveal the potential of AERM for the treatment of NAFLD and management of obesity and comorbidities.
ARTICLE | doi:10.20944/preprints201701.0117.v1
Subject: Life Sciences, Molecular Biology Keywords: blunt snout bream; high carbohydrate; transcriptome; metabolomics; insulin resistance; fatty liver disease
Online: 26 January 2017 (03:52:10 CET)
A high intake of carbohydrates, associated with obesity, is one of the major causes of fatty liver disease in humans. This study investigated how high carbohydrate intake induces fatty liver disease in Blunt snout bream (Megalobrama amblycephala). Blunt snout bream were fed a high-carbohydrate diet (HCBD) for 60 days. Their growth indices were evaluated, and the transcriptomes, metabolites, biochemistry, and histology of their blood and livers were analyzed. The final weight, weight gain, specific growth rate, and feed conversion ratio were all higher in the HCBD group than in the control group, but not significantly so (P > 0.05). The hepatosomatic index (HSI) differed significantly in the two groups (P < 0.05), and the metabolomics results showed that a high carbohydrate intake induced significant increases in plasma α/β-glucose, succinate, and tyrosine, which could increase hepatic glycogen and triglyceride. Low levels of betaine were also found in the livers of the HCBD group. The histology and blood biochemistry results suggested abnormal liver, with excessive lipid accumulation and liver damage. A transcriptome analysis and quantitative reverse transcription–PCR (RT–qPCR) indicated that the expression of the factors INSR, IRS, PI3K, PDK, AKT, ACC, IL6, AP1, ChREBP-MLX, PEPCK, and FBP in the insulin signaling pathway was significantly upregulated and that of SOCS3, GSK3β, and AMPK significantly downregulated in the HCBD. This pattern is associated with the nonalcoholic fatty liver disease (NAFLD) pathway. This study extends our understanding of how high carbohydrate causes increased fat deposition in the liver, enhanced glycolysis (α/β-glucose) in the plasma, and reduced betaine in the liver. This leads to activation of hepatocyte insulin resistance and lipogenesis by regulating the expression of genes related to fatty liver disease.
REVIEW | doi:10.20944/preprints201912.0165.v2
Subject: Medicine & Pharmacology, Nutrition Keywords: glucose; pentose phosphate pathway; NADPH; redox balance; glycogen; glycolysis; stress resistance; insulin resistance
Online: 30 January 2020 (12:49:19 CET)
A human organism depends on stable glucose blood levels in order to maintain the metabolic needs. Glucose is considered as the most important energy source and glycolysis is postulated as a backbone pathway. However, when glucose supply is limited, ketone bodies and amino acids can be used to produce enough ATP. In contrast, for the functioning of pentose phosphate pathway (PPP) glucose is essential and cannot be substituted by other metabolites. PPP generates and maintains levels of NADPH needed for reduction of oxidized glutathione and protein thiols, synthesis of lipids and DNA as well as for xenobiotic detoxification, regulatory redox signaling and counteracting infections. Flux of glucose into a PPP, particularly under extreme oxidative and toxic challenges is critical for survival, whereas the glycolytic pathway is primarily activated when glucose is abundant, and there is lack of NADP+ that is required for activation of glucose-6 phosphate dehydrogenase. An important role of glycogen stores in resistance to oxidative challenges is discussed. Current evidences explain disruptive metabolic effects and detrimental health consequences of chronic nutritional carbohydrate overload and provides new insights into positive metabolic effects of intermittent fasting, caloric restriction, exercise, and ketogenic diet through modulation of redox homeostasis.
REVIEW | doi:10.20944/preprints201904.0155.v1
Subject: Biology, Physiology Keywords: Rho GTPases; metabolism; glucose homeostasis; GLUT4 translocation; skeletal muscle; pancreas; insulin; diabetes; ageing
Online: 13 April 2019 (05:20:35 CEST)
Rho guanosine triphosphatases (GTPases) are key regulators in a number of cellular functions, including actin cytoskeleton remodeling and vesicle traffic. Traditionally, Rho GTPases are studied because of their function in cell migration and cancer, while their roles in metabolism are less documented. However, emerging evidence implicates Rho GTPases as regulators of processes of crucial importance for maintaining metabolic homeostasis. Thus, the time is now ripe for reviewing Rho GTPases in the context of metabolic health. Rho GTPase-mediated key processes include the release of insulin from pancreatic β-cells, glucose uptake into skeletal muscle and adipose tissue, and muscle mass regulation. Through the current review, we cast light on the important role of Rho GTPases in skeletal muscle, adipose tissue, and the pancreas and mechanisms by which Rho GTPases act to regulate glucose metabolism in health and disease. We also describe challenges and goals for future research.
ARTICLE | doi:10.20944/preprints201902.0100.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: obesity; diabetes; body weight; body composition; glucose tolerance; insulin tolerance; incretin; energy expenditure
Online: 12 February 2019 (10:37:42 CET)
Background/Goals: The gut hormone PYY secreted from intestinal L-cells has been implicated in the mechanisms of satiation via Y2-receptor (Y2R) signaling in the brain and periphery and is a major candidate for mediating the beneficial effects of bariatric surgery on appetite and body weight. Methods: Here we assessed the role of Y2R signaling in the response to low- and high-fat diets and its role in the effects of Roux-en-Y gastric bypass (RYGB) surgery on body weight, body composition, food intake, energy expenditure and glucose handling, in global Y2R-deficient (Y2RKO) and wildtype mice made obese on high-fat diet. Results: Both male and female Y2RKO mice responded normally to low- and high-fat diet in terms of body weight, body composition, fasting levels of glucose and insulin, as well as glucose and insulin tolerance for up to 30 weeks of age. Contrary to expectations, obese Y2RKO mice also responded similarly to RYGB compared to WT mice for up to 20 weeks after surgery, with initial hypophagia, sustained body weight loss, and significant improvements in fasting insulin, glucose tolerance, HOMA-IR, and liver weight compared to sham-operated mice. Furthermore, non-surgical Y2RKO mice weight-matched to RYGB showed the same improvements in glycemic control as Y2RKO mice with RYGB that were similar to WT mice. Conclusions: PYY signaling through Y2R is not required for the normal appetite-suppressing and body weight-lowering effects of RYGB in this global knockout mouse model. Potential compensatory adaptations of PYY signaling through other receptor subtypes or other gut satiety hormones such as GLP-1 remain to be investigated.
ARTICLE | doi:10.20944/preprints201804.0049.v1
Subject: Life Sciences, Endocrinology & Metabolomics Keywords: garcinia mangostana; inflammation; insulin resistance; metabolic syndrome; diabetes; xanthones; mangostin; phytotherapy; dietary supplements
Online: 4 April 2018 (06:19:44 CEST)
Insulin resistance is the most important underlying cause of obesity and type 2 Diabetes (T2DM), and insulin sensitizing treatments have proved effective in preventing diabetes and inducing weight loss. Obesity and T2DM are also associated with increased inflammation. Mangosteen is a tropical tree, whose fruits, widely known for their antioxidant properties, have been recently suggested having a possible further role in the treatment of obesity and T2DM. The objective of this pilot study has been to evaluate safety, compliance and efficacy of mangosteen on insulin resistance, weight management, and inflammatory status in obese female patients with insulin resistance. 22 patients were randomized 1:1 to behavioral therapy alone or behavioral therapy and mangosteen and 20 completed the 26-week study. The mangosteen group reported a significant improvement in insulin sensitivity (HOmeostatic Model Assessment-Insulin Resistance, HOMA-IR -53.22% vs -15.23%, p=.0037), and a trend decrease in inflammation markers serum levels, together with trend greater weight loss and trend increased HDL levels. No side effect attributable to treatment was reported. Given the positive preliminary results we report and the excellent safety profile, we suggest a possible role of mangosteen in the treatment of obesity, insulin resistance and inflammation.
ARTICLE | doi:10.20944/preprints201802.0187.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: insulin resistance; body weight; body fat; visceral fat; waist circumference; body mass index
Online: 28 February 2018 (04:43:50 CET)
The incidence of obesity which leads to insulin resistance (IR) and metabolic disorder increases in developing countries including Indonesia. Male adult has higher risk to have abdominal obesity than female which is associated with cardiometabolic disorders. Several anthropometric measurements have been proposed to predict IR. The aim of this study was to investigate whether body mass, body mass index (BMI), waist circumference (WC), body fat percentage (BF) or visceral fat percentage (VF) could become a better predictor of IR in healthy young male adult. Total of 140 healthy young male adults ranging from 18-25 years were recruited in the study. Insulin resistance was measured by calculating Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). Subjects with HOMA-IR value >75th percentile with cut off 3.75 were defined as IR. Anthropometric measurements included body weight, BMI, WC were performed whereas BF and VC were measured by bioelectrical impedance analysis (BIA). IR had significant strong correlation with body weight, BMI, WC, BF and VF. The area under curve of body mass, BF, VF were greater than WC and BMI. Anthropometric measurements correlated strongly with IR but body weight, BF, VF have stronger correlation than WC and BMI in healthy young male adult.
ARTICLE | doi:10.20944/preprints201610.0027.v1
Subject: Biology, Physiology Keywords: Liver X receptor (LXR); Peroxisome proliferator-activated receptor (PPARγ); Adipose expansion; Insulin resistance
Online: 10 October 2016 (07:56:30 CEST)
Liver X receptors (LXR) are deemed as potential drug targets for atherosclerosis, whereas a role in adipose tissue expansion and its relation to insulin sensitivity remains unclear. To assess the metabolic effects of LXR activation, C57BL/6 mice on a high-fat diet (HFD) were treated with the dual LXRα/β agonist T0901317 (30 mg/kg per day) for 3 weeks. Differentiated 3T3-L1 was used for analysing the effect of T0901317 on glucose uptake.T0901317 reduced fat mass, accompanied by a massive fatty liver and lower adipokine levels in circulation of HFD mice. Increased adipocyte apoptosis and macrophage infiltration were found in epididymal fat of T0901317-treated HFD mice. In addition, T0901317 treatment promoted basal lipolysis, but blunted the anti-lipolytic action of insulin. Furthermore, LXR activation antagonized PPARγ target genes in epididymal fat and PPARγ-PPRE binding activity in 3T3-L1 adipocytes. Although the glucose tolerance was comparable to that in vehicle-treated HFD mice, the insulin tolerance was significantly decreased in T0901317-treated HFD mice, indicating decreased insulin sensitivity by T0901317 administration, and which was further supported by impaired insulin signalling found in epididymal fat and decreased insulin-induced glucose uptake in 3T3-L1 by T0901317administration. These findings reveal that LXR activation impairs adipose expansion which contributes to decreased insulin sensitivity.
REVIEW | doi:10.20944/preprints202009.0399.v1
Subject: Biology, Other Keywords: inositide; phosphoinositide; 5-phosphatase; INPP5K; SKIP; phosphatidylinositol 3,4,5-trisphosphate; phosphatidylinositol 4,5-bisphosphate; congenital muscular dystrophy; cataract; intellectual disability; insulin signaling; insulin resistance; endoplasmic reticulum; endoplasmic reticulum stress; unfolded protein response
Online: 17 September 2020 (11:19:10 CEST)
INPP5K (Inositol Polyphosphate 5-Phosphatase K, or SKIP (for Skeletal muscle and Kidney enriched Inositol Phosphatase) is a member of the phosphoinositide 5-phosphatases family. Its protein structure is comprised of a N-terminal catalytic domain which hydrolyses both PtdIns(4,5)P2 and PtdIns(3,4,5)P3, followed by a SKICH domain at the C-terminus which is responsible for protein-protein interactions and subcellular localization of INPP5K. Strikingly, INPP5K is mostly concentrated in the endoplasmic reticulum, although it is also detected at the plasma membrane, in the cytosol and the nucleus. Recently, mutations in INPP5K have been detected in patients with a rare form of autosomal recessive congenital muscular dystrophy with cataract, short stature and intellectual disability. INPP5K functions extend from control of insulin signaling, endoplasmic reticulum stress response and structural integrity, myoblast differentiation, cytoskeleton organization, cell adhesion and migration, renal osmoregulation, to cancer. The goal of this review is thus to summarize and comment recent and less recent data in the literature on INPP5K, in particular on the structure, expression, intracellular localization, interactions and functions of this specific member of the 5-phosphatases family.
ARTICLE | doi:10.20944/preprints202203.0031.v1
Subject: Medicine & Pharmacology, Sport Sciences & Therapy Keywords: obesity; high-intensity interval training; heart rate variability; inflammatory markers; insulin resistance; autonomic function
Online: 2 March 2022 (02:44:02 CET)
Obesity is linked to an inflammatory process, with adipocyte release triggering insulin resistance (IR) and autonomic imbalance. A cardiovagal trainning protocol has shown favorable results in autonomic balance and decrease of inflammatory markers. The aim of this study was to analyze the autonomic behavior related to inflammatory and metabolic parameters in obese people after a cardiovagal exercise protocol. Twenty people with obesity, were distributed by their HOMA-IR value: obese without IR (n/IR) (n=8) and obese with IR (y/IR) (n=12). The cardiovagal training program was carried out in both groups for 8 weeks at a frequency of 5 times per week. A blood sample was obtained to determine insulin, leptin, TNF alpha and IL6 levels, in addition to determining the HOMA-IR index and autonomic function was measured by heart rate variability. Changes were recorded in the OB-IR group, a decrease in inflammatory markers, glycemia and a reduction of sympathetic activity after the cardiovagal training intervention. In addition, significant differences between the y/IR and n/IR groups were shown in insulin, leptin, TNFa and IL6 values. It can be concluded that after 4 weeks of intervention with a cardiovagal trainning protocol, parasympathetic modulation increased and inflammatory markers decreased in obese subjects.
ARTICLE | doi:10.20944/preprints202108.0006.v1
Subject: Medicine & Pharmacology, Allergology Keywords: cultured neurons; insulin; glutamate; [Ca2+]i; mitochondrial potential; ATP; oxygen consumption rate; superoxide; ROS
Online: 2 August 2021 (09:10:44 CEST)
Glutamate excitotoxicity is implicated in the pathogenesis of many disorders, including stroke, traumatic brain injury, and Alzheimer’s disease, for which central insulin resistance is a comorbid condition. Massive glutamate release primarily through ionotropic N-methyl-D-aspartate receptors (NMDARs) causes a sustained rise in [Ca2+]i, followed by mitochondrial depolarization and an increase in intracellular O2• (superoxide) production. Recently, we found that insulin protected neurons against excitotoxicity by diminishing the delayed calcium deregulation (DCD), However, a role of insulin in superoxide production in excitotoxicity still needs to be clarified. The present study is aimed to investigate the effects of insulin on glutamate-evoked superoxide generation and DCD using the fluorescent indicators dihydroethidium, MitoSOX Red, and Fura-FF in rats cultured cortical neurons. We found that insulin significantly diminished both the intracellular and mitochondrial superoxide production in neurons exposed to glutamate and there was a strong linear correlation between [Ca2+]i and intracellular superoxide. MK 801, an inhibitor of NMDAR-gated Ca2+ influx, completely abrogated the glutamate effects in both the presence and absence of insulin. In experiments on sister cultures, insulin diminishes neuronal death. Thus, collectively, data obtained suggest that insulin diminishes glutamate-induced superoxide production in neurons via fall of [Ca2+]i increased and thereby improves viability of neurons
ARTICLE | doi:10.20944/preprints202105.0258.v1
Subject: Life Sciences, Biochemistry Keywords: ANGPTL3-DOCK7; irisin; c-peptide; triglyceride; interleukin 13; lipid metabolism; insulin resistance; Arab population
Online: 12 May 2021 (07:28:31 CEST)
ANGPTL3 is an important regulator of lipid metabolism. Its inhibition in people with hypercholesteremia reduces plasma lipid levels dramatically. Genome-wide association studies have associated ANGPTL3 variants with lipid traits. Irisin, an exercise modulated protein, has been associated with lipid metabolism. Intracellular accumulation of lipids impairs insulin action and contributes to metabolic disorders. In this study, we evaluate the impact of ANGPTL3 variants on levels of irisin and markers associated with lipid metabolism and insulin resistance. ANGPTL3 rs1748197 and rs12130333 variants were genotyped in a cohort of 278 Arab individuals from Kuwait. Levels of irisin and other metabolic markers were measured by ELISA. Significance of association signals was assessed using Bonferroni-corrected P-values and empirical P-values. The study variants were significantly associated with low levels of c-peptide and irisin. Levels of c-peptide and irisin were mediated by interaction between carrier genotypes (GA+AA) at rs1748197 and measures of IL13 and TG, respectively. While levels of c-peptide and IL13 were directly correlated in individuals with reference genotype, they were inversely correlated in individuals with carrier genotype. Irisin correlated positively with TG which is strong in individuals with carrier genotypes. These observations illustrate ANGPTL3 as a potential link connecting lipid metabolism, insulin resistance and cardioprotection.
REVIEW | doi:10.20944/preprints201810.0166.v1
Subject: Life Sciences, Endocrinology & Metabolomics Keywords: FTO; liver; gluconeogenesis; lipogenesis; glucose; insulin; type 2 diabetes; non-alcoholic fatty liver disease
Online: 9 October 2018 (03:52:49 CEST)
Common genetic variants of the fat mass and obesity associated (FTO) gene are strongly associated with obesity and type 2 diabetes. FTO is ubiquitously expressed, but appears to have tissue-specific roles. Earlier studies have focused on the role of hypothlamic FTO in the regulation of metabolism. However, it appears that FTO plays a role in the regulation of metabolism in a tissue-specific manner. Recent studies suggest that expression of hepatic FTO is regulated by metabolic signals such as nutrients and hormones and altered FTO levels in liver affects glucose and lipid metabolism. This review outlines recent findings on hepatic FTO in the regulation of metabolism, with particular focus on hepatic glucose and lipid metabolism. It is proposed that abnormal activity of hepatic signaling pathways involving FTO links metabolic impairments such as obesity, type 2 diabetes and nonalcoholic fatty liver disease (NAFLD). Therefore, a better understanding of these pathways may lead to therapeutic approaches to treat these metabolic diseases by targeting hepatic FTO. The overall goal of this review is to place FTO within the context of hepatic regulation of metabolism.
REVIEW | doi:10.20944/preprints202112.0088.v1
Subject: Medicine & Pharmacology, Obstetrics & Gynaecology Keywords: polycystic ovary syndrome; evolution; insulin resistance; infertility; environment; toxins; endocrine disrupting chemicals; dysbiosis; lifestyle; diet
Online: 6 December 2021 (15:34:25 CET)
Polycystic ovary syndrome (PCOS) is increasingly recognized as a complex metabolic disorder that manifests in genetically susceptible women following a range of negative exposures to nutritional and environmental factors related to contemporary lifestyle. The hypothesis that PCOS phenotypes are derived from a mismatch between ancient genetic survival mechanisms and modern lifestyle practices is supported by a diversity of research findings. The proposed evolutionary model of the pathogenesis of PCOS incorporates evidence related to evolutionary theory, genetic studies, in-utero developmental epigenetic programming, transgenerational inheritance, metabolic features including insulin resistance, obesity and the apparent paradox of lean phenotypes, reproductive effects and subfertility, the impact of the microbiome and dysbiosis, endocrine disrupting chemical exposure, and the influence of lifestyle factors such as poor quality diet and physical inactivity. Based on these premises, the diverse lines of research are synthesized into a composite evolutionary model of the pathogenesis of PCOS. It is hoped that this model will assist clinicians and patients to understand the importance of lifestyle interventions in the prevention and management of PCOS and provide a conceptual framework for future research. It is appreciated that this theory represents a synthesis of the current evidence and that it is expected to evolve and change over time.
REVIEW | doi:10.20944/preprints202108.0552.v1
Subject: Life Sciences, Cell & Developmental Biology Keywords: antagonistic pleiotropy; insulin/IGF-1 signalling; hyperfunction; quasi-programs; mTOR; theories of aging; programmatic aging
Online: 30 August 2021 (16:11:02 CEST)
The process of senescence (aging) is largely determined by the action of wild-type genes. For most organisms, this does not reflect any adaptive function of senescence, but rather evolutionary effects of declining selection against genes with deleterious effects later in life. To understand aging requires an account of how evolutionary mechanisms give rise to pathogenic gene action and late-life disease, that integrates evolutionary (ultimate) and mechanistic (proximate) causes into a single explanation. A well-supported evolutionary explanation by G.C. Williams argues that senescence can evolve due to pleiotropic effects of alleles with antagonistic effects on fitness and late-life health (antagonistic pleiotropy, AP). What has remained unclear is how gene action gives rise to late-life disease pathophysiology. One ultimate-proximate account is T.B.L. Kirkwood’s disposable soma theory. Based on the hypothesis that stochastic molecular damage causes senescence, this reasons that aging is coupled to reproductive fitness due to preferential investment of resources into reproduction, rather than somatic maintenance. An alternative and more recent ultimate-proximate theory argues that aging is largely caused by programmatic, developmental-type mechanisms. Here ideas about AP and programmatic aging are reviewed, particularly those of M.V. Blagosklonny (the hyperfunction theory) and J.P. de Magalhães (the developmental theory), and their capacity to make sense of diverse experimental findings is described.
REVIEW | doi:10.20944/preprints202108.0283.v1
Subject: Life Sciences, Molecular Biology Keywords: Type 1 diabetes; human leukocyte antigen; Kuwait Type 1 Diabetes Study; Islet autoantibodies; Insulin; prediction
Online: 13 August 2021 (08:19:26 CEST)
The incidence of Type 1 Diabetes (T1D) in the Arab world, particularly, oil and gas rich Gulf Cooperative Council (GCC) countries has more than doubled in the last twenty years. Therefore, there is a dire need for careful systematic familial cohort studies, especially in high-risk populations. Several immunogenetic factors affect the pathogenesis of the disease. Genes in the human leukocyte antigen (HLA) account for the major genetic susceptibility to the disease. The triggering agents initiate disease onset by destruction of pancreatic β-cells. The autoantibodies against glutamic acid decarboxylase (GADA), insulinoma antigen-2 (IA-2A), insulin (IAA), and zinc transporter-8 (ZnT-8A) comprise the most reliable biomarkers for T1D in both children and adults. Although three of the GCC countries, namely Kuwait, Saudi Arabia and Qatar are among the top 10 countries with high incidence rate of T1D, no proper diagnostic and prediction tools were applied in the region. Understanding the disease sequelae in a homogenous gene pool with high consanguinity in the GCC could help solve the challenges in understanding pathogenesis, as well as hasten the prevention of T1D. Arab states must incorporate T1D predictive and intervention policies on a war-footing basis to minimize the burden of this serious disease.
REVIEW | doi:10.20944/preprints202101.0570.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Advanced glycation end-products; contact dermatitis; granuloma annulare; insulin; lipoatrophy; lipohypertrophy; necrobiosis lipoidica; skin autofluorescence
Online: 27 January 2021 (16:24:01 CET)
Skin involvement is an overlooked aspect in the management of paediatric patients with type 1 diabetes. A comprehensive search of published literature using the PubMed database was carried out using the following key terms: “children”, “pediatric/paediatric patients”, “skin”, “skin disorders”, “type 1 diabetes”. Dermatological side effects are frequently observed among diabetic children and adolescents. Insulin-induced lipodystrophies and allergic contact dermatitis caused by insulin pumps or glycaemic sensors are the most common skin reactions in these patients. Furthermore, several diabetes-associated skin diseases such as necrobiosis lipoidica, granuloma annulare, vitiligo, and bullosis diabeticorum may already be present in paediatric age. Paediatric diabetes specialists should pay attention to their patients’ skin so as to recognize these disorders, identify the potential causes, and choose the most suitable treatment. Finally, the evaluation of skin concentrations of advanced glycation end-products using non-invasive diagnostic techniques may be used to assess the risk of chronic complications of diabetes as early as adolescence.
ARTICLE | doi:10.20944/preprints201705.0189.v1
Subject: Life Sciences, Biochemistry Keywords: loureirin B; Ins-1 cells; Insulin secretion; KATP channel; influx of Ca2+; expression of Cx43
Online: 26 May 2017 (04:52:12 CEST)
The development of new diabetes drugs continues to be explored. Loureirin B, a flavonoid, extracted from Dracaena cochinchinensis, has been confirmed to increase insulin secretion and decrease blood glucose levels. For understanding the mechanism, a series of experiments had been employed based on computational methods and cell experiments. The insulin secretion significantly increased with the incubation of 0.01μM loureirin B for 4 hours. The viability of Ins-1 cells showed no significant difference with the treatment of loureirin B. Through computational methods, we hypothesized that loureirin B could interacts with KATP channels to promote insulin secretion. In cell experiments, it could be found that the current of KATP channel of Ins-1 cells was inhibited by the effect of loureirin B. After then, the voltage-dependent calcium channels were activated, the increase of Cx43 protein expression might mediate the Ca2+ to the intracellular. In summary, it could be concluded that loureirin B promoted insulin secretion mainly through inhibiting KATP current, the influx of Ca2+ to the Intracellular and the expression of Cx43.
REVIEW | doi:10.20944/preprints202104.0742.v1
Subject: Keywords: Diabetes mellitus; Glucose metabolism; Histone deacetylase; HDACs; Histone deacetylase inhibitor; HDACi, Insulin release; Sirtuins, Sirtuin activation
Online: 28 April 2021 (10:23:12 CEST)
Diabetes mellitus (DM) is one of the principal manifestations of metabolic syndrome and its prevalence with modern lifestyle is increasing incessantly. Chronic hyperglycemia can induce several vascular complications that were referred to be the major cause of morbidity and mortality in DM. Although several therapeutic targets have been identified and accessed clinically, the imminent risk of DM and its prevalence are still ascending. Substantial pieces of evidence revealed that histone deacetylase (HDAC) isoforms can regulate various molecular activities in DM via epigenetic and post-translational regulation of several transcription factors. To date, 18 HDAC isoforms have been identified in mammals that were categorized into 4 different classes. Classes I, II, and IV are regarded as classical HDACs, which operate through a Zn-based mechanism. In contrast, class III HDACs or Sirtuins depend on nicotinamide adenine dinucleotide (NAD+) for their molecular activity. Functionally, most of the HDAC isoforms can regulate β cell fate, insulin release, insulin expression and signaling, and glucose metabolism. Moreover, the roles of HDAC members have been implicated in the regulation of oxidative stress, inflammation, apoptosis, fibrosis, and other pathological events, which substantially contribute to diabetes-related vascular dysfunctions. Therefore, HDACs could serve as the potential therapeutic target in DM towards developing novel intervention strategies. This review sheds light on the emerging role of HDACs/isoforms in diabetic pathophysiology and emphasized the scope of their targeting in DM for constituting the novel interventional strategies for metabolic disorders/complications.
REVIEW | doi:10.20944/preprints202101.0461.v1
Subject: Life Sciences, Biochemistry Keywords: Diuretic hormone; sleep, feeding; metabolism; ion transport peptide; tachykinin; short neuropeptide F; insulin-like peptide; neuromodulation
Online: 25 January 2021 (09:23:22 CET)
Leucokinins (LKs) constitute a family of neuropeptides identified in numerous insects and many other invertebrates. The LKs act on G-protein coupled receptors that display only distant relations to other known receptors. In adult Drosophila, 26 neurons/neurosecretory cells of three main types express LK. The four brain interneurons are of two types, and these are implicated in several important functions in the fly’s behavior and physiology, including feeding, sleep-metabolism interactions, state-dependent memory formation, as well as modulation of gustatory sensitivity and nociception. The 22 neurosecretory cells (ABLKs) of the abdominal neuromeres coexpress LK and a diuretic hormone (DH44), and together these regulate water and ion homeostasis and associated stress, as well as food intake. In Drosophila larvae, LK neurons modulate locomotion, escape responses, and aspects of ecdysis behavior. A set of lateral neurosecretory cells, ALKs, in the brain express LK in larvae, but inconsistently so in adults. These ALKs coexpress three other neuropeptides and regulate water and ion homeostasis, feeding and drinking, but the specific role of LK is not yet known. This review summarizes Drosophila data on embryonic lineages of LK neurons, functional roles of individual LK neuron types, interactions with other peptidergic systems, and orchestrating functions of LK.
ARTICLE | doi:10.20944/preprints202007.0543.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: nonalcoholic fatty liver disease; lean nonalcoholic fatty liver disease; visceral fat; non-obese; fatty liver; insulin resistance
Online: 23 July 2020 (09:38:15 CEST)
Asians are known to more likely than Westerners develop fatty liver and lifestyle-related diseases despite their weight. However, the relationship between fat accumulation and lifestyle-related diseases in non-obese Asians is unknown. Therefore, this study aimed to analyze visceral fat and hepatic fat in participants with a normal body mass index (BMI) and examine their characteristics during a medical checkup. This cross-sectional study was conducted on 663 of 1,142 patients who underwent abdominal ultrasonography and who had an alcohol intake (converted to ethanol) of <30 g/day for males and <20 g/day for females and a BMI of <25 kg/m2 during a health checkup. Participants were classified into four groups: group A, visceral fat accumulation (VFA) (−) and fatty liver (FL) (−) (n = 549); group B, VFA (+) and FL(−) (n = 32); group C, VFA (−) and FL (+) (n = 58); and group D, VFA (+) and FL (+) (n = 24). The frequencies of lifestyle-related disease complications, liver function tests, and liver fibrosis were evaluated among the four groups. Compared with group A (control), groups B, C, and D had higher number of males; BMI; abdominal circumference, ALT, AST, γ-GTP, triglyceride, uric acid, fasting blood sugar levels; and incidence of hyperlipidemia. Groups C and D had higher ALT, HbA1c, cholinesterase, and triglyceride levels; FIB4 index; and number of patients with diabetes mellitus (DM) than groups A and B; however, there was no difference between groups A and B. FL is a risk factor of DM and liver fibrosis in non-obese Japanese individuals; however, VFA only is not a risk factor of DM and liver fibrosis.
ARTICLE | doi:10.20944/preprints201808.0365.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: coffee; insulin resistance; metabolic syndrome X; Non-alcoholic fatty liver disease; Carbon-13 magnetic resonance spectroscopy; phytotherapy
Online: 21 August 2018 (04:38:00 CEST)
Literature is inconsistent as to how coffee affects the features of the metabolic syndrome (MetS), and which bioactive compounds are responsible for its metabolic effects. We aimed to compare the in-vivo effects of unfiltered coffee with a selected mixture of its compounds on diet-induced MetS. 24 male Sprague-Dawley rats were fed a high-fat (35% W/W) food plus 20% W/W fructose in drinking water for 14 weeks, and were randomized into three groups: control, coffee, or nutraceuticals (5-O-caffeoylquinic acid, caffeic acid, and trigonelline). Coffee or nutraceuticals were provided in drinking water in a dosage equal to 4 cups/day in a human. Compared to the controls, only coffee supplementation decreased total food intake, weight gain, and estimated average plasma glucose. Surrogate measures of insulin resistance (fasting insulin, HOMA-IR, and oral glucose tolerance) were improved at endpoint in the coffee group. Circulating triglyceride levels were also reduced by coffee. Histopathological and quantitative measurements indicated lower grades of liver steatosis after long-term coffee consumption. In conclusion, a combination of phenolic acids and trigonelline was not as effective as coffee per se in improving the components of the MetS. This points to the role of other coffee chemicals and a potential synergism between compounds.
ARTICLE | doi:10.20944/preprints202107.0456.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: Real-time continuous glucose monitoring; Intermittently scanned continuous glucose monitoring; Type 1 diabetes; Glucose variability; Hypoglycemia; Insulin resistance
Online: 20 July 2021 (14:58:11 CEST)
The switch from intermittently scanned continuous glucose monitoring (isCGM) to real-time (rt) CGM could improve glycemic management in suboptimal controlled type 1 diabetes patients, but long-term study is lacking. We evaluated retrospectively the ambulatory glucose profile (AGP) in such patients after switching from Free Style libre 1 (FSL1) to Dexcom G4 (DG4) over 1 year. Patients (n=21, 43±15 years, BMI 25±5, HbA1c 8.1±1.0%) had severe hypoglycemia and/or HbA1c≥8%. AGP metrics (time-in-range (TIR) 70-180 mg/dL, time-below-range (TBR)<70 mg/dL or <54 mg/dL, glucose coefficient of variation (%CV), time-above-range (TAR) >180 mg/dL or >250 mg/dL, glucose management indicator (GMI), average glucose) were collected the last 3 months of FSL1 use (M0) and of DG4 for 3, 6 (M6) and 12 (M12) months of use. Values were means ± standard deviation or medians [Q1;Q3]. At M12 versus M0, the higher TIR (50±17 vs. 45±16, P=0.036), and lower TBR<70 mg/dL (2.5 [1.6;5.5] vs. 7.0 [4.5;12.5], P=0.0007), TBR<54 mg/dL (0.7 [0.4;0.8] vs. 2.3 [0.8;7.0], P=0.007) and %CV (39±5 vs. 45±8, P=0.0009), evidenced a long-term effectiveness of the switch. Compared to M6, TBR<70mg/dL decreased, %CV remained stable, while the improvement on hyperglycemia exposure decreased (higher GMI, TAR and average glucose). This switch was a relevant therapeutic option, though a loss of benefit on hyperglycemia stressed the need for optimized management of threshold alarms. Nevertheless, few patients attained the recommended values for AGP metrics, and the reasons why some patients are “responders” vs “non-responders” warrant to be investigated.
ARTICLE | doi:10.20944/preprints202205.0336.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: Long non-coding RNA; Prostate androgen-regulated transcript 1; miR-204-3p; insulin-like growth factor binding protein 2
Online: 24 May 2022 (11:57:26 CEST)
Lung cancer is a common malignant tumor of the lung and the leading cause of cancer mortality worldwide. Non-small-cell lung cancer (NSCLC) accounts for 80%–85% of lung cancer, 40% of NSCLCs will have spread beyond the lungs by the time it is diagnosed. Long non-coding RNA (LncRNA) prostate androgen-regulated transcript 1 (PART-1) was reported that promote the development of several cancers. In the current study, we conducted experiments to investigate the role of PART-1 in the proliferation, invasion, and migration of NSCLC. The expression level of the PART-1 gene increased significantly in the NSCLC cell lines, including A549, H1229, H1650, H1975, and PC9. Knocking down of PART-1 inhibited the proliferation, invasion, and migration of A549 cells, moreover, decreased the tumor proliferation in nude mice. We confirmed that PART-1 targeted miR-204-3p directly, and miR-204-3p targeted the insulin-like growth factor binding protein 2 (IGFBP-2) directly. Furthermore, we discovered that PART-1 involved the NSCLC progression by regulating the miR-204-3p-targeted IGFBP-2 pathway. LncRNA PART-1 might be a target for treating NSCLC, and a warning sign of diagnosis of early lung cancer.
REVIEW | doi:10.20944/preprints202201.0017.v1
Subject: Medicine & Pharmacology, Pediatrics Keywords: short stature; growth hormone deficiency; insulin-like growth factor-1; growth hormone stimulation tests; neurosecretory dysfunction; final height; retesting
Online: 4 January 2022 (18:05:06 CET)
According to current guidelines, growth hormone (GH) therapy is strongly recommended in children and adolescents with GH deficiency (GHD) in order to accelerate growth rate and attain normal adult height. The diagnosis of GHD requires demonstration of decreased GH secretion in stimulation tests, below the established threshold value. Currently, GHD in children is classified as secondary insulin-like growth factor-1 (IGF-1) deficiency. Most of children diagnosed with isolated GHD presents with normal GH secretion at the attainment of near-final height or even in mid-puberty. The most important clinical problems, related to the diagnosis of isolated GHD in children and to optimal duration of rhGH therapy include: arbitrary definition of subnormal GH peak in stimulation tests, disregarding factors influencing GH secretion, insufficient diagnostic accuracy and poor reproducibility of GH stimulation tests, discrepancies between spontaneous and stimulated GH secretion, clinical entity of neurosecretory dysfunction, discrepancies between IGF-1 concentrations and results of GH stimulation tests, significance of IGF-1 deficiency for the diagnosis of GHD, a need for validation IGF-1 reference ranges. Many of these issues have remained unresolved for 25 years or even longer. It seems that finding solutions to them should optimize diagnostics and therapy of children with short stature.
ARTICLE | doi:10.20944/preprints202103.0708.v1
Subject: Life Sciences, Biochemistry Keywords: Adolescents; high sensitivity C-reactive protein; Insulin-like growth factor binding proteins; Obesity; Oxidized Low-Density Lipoprotein; Predictive diagnostics
Online: 29 March 2021 (16:33:20 CEST)
Insulin-like growth factor binding proteins (IGFBPs) are critical modulators of the metabolism. In adults, IGFBPs are associated with obesity and insulin resistance but the association of IGFBPs with metabolic homeostasis in children and adolescents is not fully characterized. In this study we investigated the association of plasma IGFBPs (IGFBP-1, 3 and 7) with weight status, central adiposity and cardiovascular disease markers Hs-CRP and Ox-LDL. A total of 420 adolescents (age 11-14 years) were randomly recruited from public middle schools in Kuwait. IGFBPs were measured using bead-based multiplexing while Hs-CRP and Ox-LDL were measured using ELISA. IGFBP-1 levels were significantly lower in obese and overweight participants compared to normal weight children. Only IGFBP-1 was negatively associated with waist circumference to height (WC/Ht) ratio. IGFBP-1 was negatively correlated with Hs-CRP while IGFBP-3 and IGFBP-7 were negatively correlated with Ox-LDL. These data demonstrate a robust negative association of IGFBP-1, but not IGFBP-3 or -7, with overweight and obesity, and the inflammation marker Hs-CRP. Central adiposity (WC/Ht ratio) was a stronger predictor of IGFBP-1 than BMI-for-age z-score. IGFBP-1 could thus be used as a sensitive predictive diagnostic tool for obesity and its subsequent effects in screening and monitoring of obesity-related metabolic complications in adolescents.
REVIEW | doi:10.20944/preprints202103.0571.v3
Subject: Medicine & Pharmacology, Allergology Keywords: diet; calorie restriction; ketosis; fasting; health span; lifespan; metabolic syndrome; insulin resistance; chronic non-communicable diseases; low-calorie; low-carb
Online: 12 April 2021 (13:06:01 CEST)
As Chronic Non-Communicable Diseases (CNCD) increase, preventive approaches become more crucial. In this review, Calorie Restriction (CR) effects on human beings were evaluated, comparing benefits and risks of different CR diets: classic CR vs ketosis-inducing diets, including Intermittent Fasting (IF), Classic Ketogenic Diet (CKD), Fasting Mimicking Diet (FMD), Very-Low-Calorie Ketogenic Diet (VLCKD) and Spanish Ketogenic Mediterranean Diet (SKMD). Special emphasis on Insulin Resistance (IR) was placed, as it mediates Metabolic Syndrome (MS), a risk factor for CNCD, and predicts MS diagnosis. CR is the most robust intervention known to increase lifespan and health span, with high evidence and known biochemical mechanisms. CR improves cardiometabolic risk parameters, boosts exercise insulin sensitivity response, and there may be benefits of implementing moderate CR on healthy young and middle-aged individuals. However, there is insufficient evidence to support long-term CR. CKD is effective for weight and MS management, and may have additional benefits such as prevention of muscle loss and appetite control. SKMD has extreme significance benefits for all the metabolic parameters studied. Studies show inconsistent benefits of IF compared to classic CR. More studies are required to study biochemical parameters, reinforce evidence, identify risks, and seek effective and safe nutritional CR approaches.
ARTICLE | doi:10.20944/preprints201701.0093.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: 22:6 docosahexaenoic acid; ω-3 fatty acids; offspring of obese mothers; offspring of lean mothers; insulin-dependent skeletal muscle glucose uptake
Online: 20 January 2017 (04:59:25 CET)
Background: Obesity among pregnant women is common, and their offspring are predisposed to obesity, insulin resistance, and diabetes. Circulating metabolites that are related to insulin resistance and are associated with this decreased tissue-specific uptake are unknown. Here, we assessed metabolite profiles in elderly women and who were either female offspring from obese mothers (OOM) or offspring of lean mothers (OLM). Metabolic changes were tested for associations with metrics for insulin resistance. Methods: 37 elderly women were separated into an elderly offspring from obese mothers (OOM; n = 17) and elderly offspring from lean/normal weight mothers (OLM; n = 20) groups. We measured plasma metabolites using 1H-NMR and also insulin-dependent tissue specific glucose uptake in skeletal muscle were assessed. Associations were made between metabolites and glucose uptake. Results: Compared to the OLM group, we found that the 22:6 docosahexaenoic acid percentage of the total long chain n-3 fatty acids (DHA/FA) was significantly lower in OOM (P = 0.015). DHA/FA associated significantly to skeletal muscle GU (P = 0.031) and M-value in the OLM group only (P = 0.050). Conclusions: DHA/FA is associated with insulin-dependent skeletal muscle glucose uptake and that this association is significantly weakened in the offspring of obese mothers.
ARTICLE | doi:10.20944/preprints202208.0324.v1
Subject: Life Sciences, Immunology Keywords: T cytotoxic cells; Leukocyte-associated Immunoglobulin-like Receptor-1; LAIR-1; Hepatitis C virus genotype 4; HCV G4; hepatocellular carcinoma; cirrhosis; immune inhibitory checkpoints; inflammation; prognosis; insulin resistance
Online: 17 August 2022 (11:38:10 CEST)
Background and Aim. Since virus-related hepatocellular carcinoma (HCC) pathogenesis involves liver inflammation, therefore, post-hepatitis C virus (HCV) infection would be a cause for liver cirrhosis that would progress to HCC. Cytotoxic T cells (Tc) are known to be involved in post-HCV complications and HCC pathogenesis. The inhibitory checkpoint Leukocyte-Associated Immunoglobulin-like Receptor-1 (LAIR-1) is expressed on Tc. Therefore, we aimed to determine whether the Tc expression level of LAIR-1 is associated with HCC progression post-HCV and moreover, to evaluate LAIR-1 expression as a non-invasive biomarker for HCC progression in the context of liver cirrhosis post-HCV genotype 4 (G4) in Egyptian patients’ peripheral venous blood liquid biopsy. We studied LAIR-1 expression on Tc related to the progression of liver cirrhosis in a case-controlled study enrolled 64 patients with post-HCV G4-HCC and 37 patients with post-HCV G4-liver cirrhosis. Methods: LAIR-1 expression was analyzed by flow cytometry. Results: LAIR-1 expression on Tc and the percentage of Tc positive for LAIR-1 (LAIR-1+Tc %) were significantly higher in the post-HCV G4-HCC group compared to the post-HCV G4-liver cirrhosis
REVIEW | doi:10.20944/preprints202010.0578.v1
Subject: Biology, Anatomy & Morphology Keywords: Type 1 diabetes; insulin therapy; C-peptide; islet transplantation, mesenchymal stem cells; induced pluripotent stem cells; pancreatic β cell; gene therapy; β-cell regeneration and reprogramming, type 1 diabetes precision medicine, diabetes personalized care.
Online: 28 October 2020 (10:02:34 CET)
Type 1 diabetes affects millions of people globally and requires careful management to avoid serious long-term complications, including heart and kidney disease, stroke, and loss of sight. The present standard-of-care for type 1 diabetes is exogenic insulin substitutional therapy. The most advanced stretegies in this area is the development of hybrid-closed loop system and the producing of long-acting insulins. Progresses in stem cell therapies have started to revolutionize the care of patients with type 1 diabetes; however, significant challenges remain including the limited islets availability, difficulties in maintaining the viability, the heterogeneity within a complex pathology and in patients’ responses to treatment. On the way, a considerable amount of efforts in maximizing the islet transplantation effectiveness by controlling the advantageous of different stem cell approaches. With the availability and the use of big data, the concept of precision medicine is gaining wide attention worldwide and could bring the dream of “presonlaized” therapies as a reality in the near future. Here we review the current range of treatments available as well as recent pre-clinical breakthroughs in the field of personlaized medicine for type 1 diabetes.