Subject: Medicine And Pharmacology, Urology And Nephrology Keywords: M2 macrophages; Fibrosis; kidney; Graft rejection
Online: 8 September 2021 (11:24:31 CEST)
Commonly macrophages are categorized into M1 and M2 subsets. M1 macrophages are defined as inflammatory cells and may contribute to tissue injury, while, M2 macrophages play a central role in tissue remodeling and control of immune responses. It seems that the existence of these cells in graft location is effective for control of inflammation and improvement of transplantation consequences. Although the relative contribution of M2 cells in organ transplantation is not clear, the accumulation of these cells in acute and chronic injury models of transplantation was shown. In some cases, the depletion of M2 cells leads to the amelioration of disease; however in other causes, skewing the response in M2 cells leads to an augmentation of graft fibrosis and worsening of graft condition. In spite of these findings, the benefits of such strategies and their implications in human disease are not clearly understood. The purpose of this mini-review is to highlight the role of alternatively activated M2-type macrophages in the improvement or reduction of the kidney transplantation outcome.
ARTICLE | doi:10.20944/preprints202010.0058.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Polyurethane; Vascular graft,; Hyperelastic; Compliance, Biomechanics
Online: 5 October 2020 (10:38:30 CEST)
The lack of suitable autologous grafts and poor compliance of existing prostheses have prompted the study of novel materials for vascular graft design. Polyurethanes (PUs) were used in the past because they have high compliance and properties that are similar to those of native tissue. In this work, the mechanical properties of a group of PUs in two states (non-hydrated and hydrated) were studied using uniaxial tensile tests, strain sweep tests, and multi-step creep recovery tests. Additionally, a hyper-elastic model based on the Mooney–Rivlin strain density function was fitted and used to model the performances of the PUs under physiological pressure and geometry conditions. The tensile tests revealed a softening phenomenon after hydration, which could potentially reduce patient discomfort and risk of vascular trauma. The ultimate strength values after hydration were similar to those reported for other vascular conduits. The strain sweep showed a strong strain dependency of the modulus indicating non-linear viscoelasticity. In the creep-recovery tests, increasing the polyethylene glycol(PEG) content enhanced the viscous flow, while the elastic behavior was enhanced with the largest concentration of polycaprolactone diol (PCL). On the other hand, under simulated physiological conditions, the compliance of the PUs showed a cyclic behavior with the time and pressure but was not affected by the radii and thickness variation, which could increase the graft compliance and geometry mismatch. Nevertheless, the compliance could be tuned using the material composition. This paper studied the biomechanics of a group of materials under simulated physiological conditions (Temperature, hydration, and pressure) to select those that could perform better for further vascular graft design.
ARTICLE | doi:10.20944/preprints202009.0066.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: arteriovenous graft; hemodialysis; vascular access; anastomosis
Online: 3 September 2020 (09:26:44 CEST)
Patients with chronic renal failure and vascular diseases require the vascular access for hemodialysis procedure to be performed with the most possible comfort for the patient. Native vein graft has a longer-lasting term in the patients’ limb, lower risk of graft infection and lower price. Native vein graft is constructed from the great saphenous vein, if the diameter of the vessel is smaller than the diameters of vessels (brachial artery, cephalic vein) it is connected to in the cubital fossa region due to the risk of graft folding, that might occur, if the graft diameter is bigger than the diameter of one or both vessels, on which anastomosis is made. The most important sizes, that were taken before graft placement, are the length of the forearm compartment, the distance between the brachial artery and cephalic vein in the cubital fossa region, distance from an expected incision in the brachial artery to the middle of the forearm compartment, the distance between incision in cephalic vein to the middle of the forearm compartment, length of the great saphenous vein (the graft) and diameters of blood vessels, used in the procedure. Finally, the right position of the graft should be determined for the successful outcome of anastomosis creating procedure.
ARTICLE | doi:10.20944/preprints201712.0048.v1
Subject: Biology And Life Sciences, Horticulture Keywords: Grafting; Pecan; Transcriptome; Graft union; Hormone
Online: 7 December 2017 (17:21:15 CET)
Pecan (Carya illinoinensis), as a popular nut tree, is widely planted in China in recent years. Grafting is an important technique for its cultivation. For a successful grafting, graft union development generally involves the formation of callus and vascular bundles at the graft union. To explore the molecular mechanism of graft union development, we applied high through-put RNA sequencing to investigate transcriptomic profiles of graft union at four time points (0d, 8d, 15d, and 30d) during pecan grafting process. We identified a total of 12,180 differentially expressed genes. In addition, we found that the content of auxin, cytokinin and gibberellin were accumulated at the graft unions during the grafting process. Correspondingly, genes involved in those hormone signaling were found to be differentially expressed. Interestingly, we found that most genes associated with cell division were up-regulated at callus formative stages, while genes related to cell elongation, secondary cell wall deposition, and programmed cell death were generally up-regulated at vascular bundle formative stages. In the meantime, genes responsible for reactive oxygen species were highly up-regulated across the graft union developmental process. These results will aid in our understanding of successful grafting in the future.
ARTICLE | doi:10.20944/preprints202103.0441.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: GBR; bone graft; DDMM; fibroblast; collagen fiber
Online: 17 March 2021 (13:19:38 CET)
Mandibular critical size defect (CSD) due to pathological conditions, trauma, and congenital disease can not heal spontaneously and predominantly filled with fibrous tissue. Therefore, a Guided Bone Regeneration (GBR) combined with bone grafting can be performed. The researchers considered using Demineralized Dentin Material Membrane (DDMM) from bovine dentine as an alternative GBR. This study aimed to determine the amount of fibroblast and collagen density after DDMM and bone graft implantation on CSD. Thirty-six Rattus norvegicus rats were used as samples. Mandibular bone defect 5x5 mm was made, then filled with bone graft and covered with Bovine Pericardium Collagen Membrane (BPCM) in the control group and DDMM in the treatment group. Six samples were sacrificed on 7, 14, and 21 days post-surgical for histology examination. There were no significant differences in the amount of fibroblast and collagen density (p-value > 0,05). The amount of fibroblast is lower and the collagen density is higher in treatment group. DDMM has microporosity to prevent connective tissue ingrowth and dentine tubules to allow growth factors release. DDMM and bone graft implantation can reduce the amount of fibroblasts and increase collagen density of CSD which potentially being used as a CSD alternative treatment for bone regeneration.
ARTICLE | doi:10.20944/preprints201903.0151.v1
Subject: Chemistry And Materials Science, Polymers And Plastics Keywords: ε-Caprolactone; block-graft copolymer; click chemistry; hydrogel
Online: 14 March 2019 (08:50:40 CET)
The cross-linkable PCL-PEG analogues block-graft copolymer was designed and synthesized, which with the copolymer of the MEO2MA and OEGMA as graft chains to improve the mPEG-b-PCL-b-mPEG copolymer the aqueous solution properties. And successfully prepared two hydrogels via a copper-catalyzed 1, 3-dipolar azide-alkyne cycloaddition reaction of alkyne-terminated poly[glycidyl methacrylate-co-2-(2-methoxyethoxy) ethyl methacrylate-co-oligo (ethylene glycol) methacrylate] [P(GMA-co-MEO2MA-co-OEGMA)] with azide end-functionalized PCL-PEG analogues block-graft copolymer, and tetrakis (2-propynyloxymethyl) -methane (TPOM) and with azide end-functionalized PCL-PEG analogues block-graft copolymer. The copolymer's chemical structure was characterized by proton nuclear magnetic resonance spectroscopy and fourier transform infrared spectroscopy. The molecular weights of the copolymers were decided with gel permeation chromatography. The water solubility and temperature sensitivity of the copolymers were studied by taking digital photos and transmittance change measured by UV spectrophotometer at different temperatures. Fluorescence probes, surface tension, dynamic light scattering and transmission electron microscopy were used to analyze the micelles that copolymers self-assembly in aqueous solution. The sol-gel behavior of copolymer solutions at high concentrations was explored by vial inversion experiments. Finally, the network structure of the gels was observed by scanning electron microscopy. These conclusions indicate that these hydrogels are expected to be used as a new material in the field of biomedicine.
TECHNICAL NOTE | doi:10.20944/preprints201804.0211.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: bone graft, resorbable barrier, sinus lift, heterologous cortical lamina
Online: 16 April 2018 (13:53:55 CEST)
Abstract A variety of surgical techniques have been developed to reconstruct the posterior maxilla when bone volume is insufficient. A barrier membrane or bone window pushed inside the sinus cavity as the ‘‘roof’’ of the sinus cavity for preserve the space and help bone. The heterologous cortical lamina is used for the mechanical support, without any grafting material, of sinus membranes resulting in only bone tissue formation and not mixed with the graft.
REVIEW | doi:10.20944/preprints202301.0462.v1
Subject: Medicine And Pharmacology, Veterinary Medicine Keywords: Bone healing; , bone fracture; bone graft; herbal medicine; osteogenesis; plants
Online: 26 January 2023 (02:58:19 CET)
Objectives Bone fractures are very common diseases, which can be caused by impact injuries or physiological disorders. Thus, the present review aimed to study the use of medicinal plants in the healing mechanism of bone fractures. Evidence acquisition Through research in the PubMed, Google Academic, and Scielo databases, this article reviews 11 ethnopharmacological studies and 34 preclinical studies on the biological actions of different plants in bone fracture healing mechanism. Results Indian tribes have highlighted in the plants ethnopharmacological study for various diseases, including bone fractures. However, despite the large citations of traditional use, technical-scientific studies are still scarce in the literature. Chenopodium ambrosioides, Piper sarmentosum, quadrangular Cissus, Ricinus communis and Radix salvia miltiorrhiza plants were the most studied in the literature regarding their osteogenic, angiogenic, anti-inflammatory and remodeling effects, acting on bone receptors, stimulating bone metabolism, increasing minerals uptake, and assisting in free radicals breakdown. Conclusion Thus, the medicinal plants use is promising in the field of bone regeneration, as well as being alternative when conventional therapies are unfeasible, increasing herbal medicines demand and popularity.
REVIEW | doi:10.20944/preprints202109.0220.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Almond; Persian walnut; Pistachio; Hazelnut; Pecan; Chestnut; grafting; graft compatibility
Online: 13 September 2021 (15:52:06 CEST)
The production and consumption of nuts are increasing in the world due to strong economic returns and the nutritional value of their products. With the increasing role and importance given to nuts (i.e., walnuts, hazelnut, pistachio, pecan, almond) in a balanced and healthy diet and in the prevention of various diseases, breeding of the nuts species has also been stepped up. Most recent fruit breeding programs have focused on scion genetic improvement. However, the use of locally adapted grafted rootstocks also enhanced the productivity and quality of tree fruit crops. Grafting is an ancient horticultural practice use in nut crops to manipulate scion phenotype and productivity and overcome biotic and abiotic stresses. There are complex rootstock breeding objectives and physiological and molecular aspects of rootstock–scion interactions in nut crops. In this review, we provide an overview of these, considering the mechanisms involved in nutrient and water uptake, regulation of phytohormones, and rootstock influences on the scion molecular processes, including long-distance gene silencing and trans-grafting. Understanding the mechanisms resulting from rootstock × scion × environmental interactions will contribute to developing new rootstocks with resilience in the face of climate change, but also of the multitude of diseases and pests and of the possible increase of their aggressiveness. They will also have to offer the premises of economic production, respectively yield and the quality, according to multiple destinations of nuts in the current consumption and food industry, but also the increasing exigencies of the consumer market and the profile industry.
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Caveolin-1; kidney transplantation; graft rejection; ischemia; reperfusion injury (IRI)
Online: 1 December 2020 (14:08:33 CET)
Acute and chronic transplant rejections due to alloreactivity are essential contributors to graft loss. However, the strength of alloreactivity is biased by non-immunological factors such as ischemia reperfusion injury (IRI). Accordingly, protection from IRI could be favorable in terms of limiting graft rejection. Caveolin-1 (Cav-1) is part of the cell membrane and an important regulator of intracellular signaling. Cav-1 has been demonstrated to limit IRI and to promote survival of a variety of cell types including renal cells under stress conditions. Accordingly, Cav-1 could also play a role in limiting anti-graft immune responses. Here, we evaluated a possible association between pretransplant serum concentrations of Cav-1 and the occurrence of rejection during follow up in a pilot study. Therefore, Cav-1-serum concentrations were analyzed in 91 patients at the time of kidney transplantation and compared to the incidence of acute and chronic rejection. Higher Cav-1 levels were associated with lower occurrence of acute rejection episodes. Moreover, Cav-1 could be therapeutically useful for attenuating graft rejection.
REVIEW | doi:10.20944/preprints202302.0240.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: Mesenchymal Stromal Cells; Graft-versus-Host-Disease; Immunomodulation; Apoptosis; Efferocytosis; Secretome
Online: 14 February 2023 (08:39:01 CET)
Mesenchymal Stromal Cells (MSCs) are multipotent, non-hematopoietic progenitor cells with a wide range of immune conditioning and regenerative potential which qualify them as potential component of cell based therapy for various autoimmune / chronic inflammatory ailments. Their immunomodulatory properties include the secretion of immunosuppressive cytokines, the ability to suppress T-cell activation and differentiation, and the induction of regulatory T-cells. In view of this and our interest, we here discuss the significance of MSC for the management of Graft-versus-Host Disease (aGVHD), one of the autoimmune manifestation in human.. In pre-clinical models, MSCs have been shown to reduce the severity of aGVHD symptoms, including skin and gut damage, which are the most common and debilitating manifestations of this disease. While initial clinical studies of MSCs in aGVHD cases were promising, the results were variable in randomized studies. So, further studies are warranted to fully understand their potential benefits, safety profile, and optimal dosing regimens. In view of these inevitable issues, here we discuss various mechanisms, how MSCs can be employed in managing aGVHD, as a therapeutic option for this disease.
ARTICLE | doi:10.20944/preprints202201.0392.v1
Subject: Medicine And Pharmacology, Ophthalmology Keywords: Pterygium; Pterygium surgery; Amniotic membrane; Conjunctival auto-graft; Polish Caucasian population
Online: 26 January 2022 (11:54:17 CET)
This study compares the efficacy of the two most commonly used surgical methods for pterygium in the Polish population, conjunctival autograft versus amniotic membrane transplantation, and to evaluate the postopera-tive recurrence rate. We retrospectively analysed the medical records of 65 patients who underwent surgery for primary or recurrent pterygium at an ophthalmology clinic in Bialystok, Poland between 2016 and 2020. Surgical success (no regrowth) occurred in almost half of the amniotic membrane patients (44%) and in most of the conjunctival autograft patients (79%); this was a significant relationship. The odds of successful surgery were 79% lower for subjects with amniotic membranes than for those with conjunc-tival autografts (OR with 95% CI = 0.21 (0.05; 0.94]; p = 0.045). Our study confirms that in Polish Caucasian population the success rate of the pro-cedure using conjunctival autograft versus the use of amniotic membrane, is in favoured for the procedure with conjunctival graft.
ARTICLE | doi:10.20944/preprints202112.0457.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: graft rejection; iPSC; differentiation; cardiomyocytes; electrospinning; CD28; CTLA-4; immune response
Online: 28 December 2021 (17:37:34 CET)
Different types of engineered cardiac constructs are being developed nowadays by many research groups. However, the immunological properties of such artificial tissues are not yet clearly understood. Previously, we have studied microfiber scaffolds carrying iPSC-derived cardiomyocytes. In this work, we evaluated the ability of these tissue-engineered constructs to activate the expression of CD28 and CTLA-4 proteins in T-lymphocytes which are early markers of the immune response. For this purpose electrospun PLA nanofibrous scaffolds were seeded with human iPSCs-CM and cultivated for 2 weeks. After, allogeneic mononuclear cells were co-cultured during 48 hours with 3 groups of samples that were tissue-engineered constructs, pure culture of cardiomyocytes and bare scaffolds followed by analysis of CD28/CTLA-4 expression on T-lymphocytes via flow cytometry. PLA scaffolds and concanavalin A (positive control) stimulation statistically significantly increased CD28 expression on CD4+ cells (up to 61.3% and 66.3%) and on CD8+ cells (up to 17.8% and 21.7%). CD28/CTLA-4 expression didn’t increase during co-cultivation of T-lymphocytes with cardiac engineered constructs and iPSC-CM monolayers. Thus, iPSCs-CM in monolayers and on PLA nanofibrous scaffolds didn’t cause T-cell activation, which allows us to expect that such cardiac constructs are not a cause of rejection after implantation.
ARTICLE | doi:10.20944/preprints202106.0545.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Bone tissue regeneration; injectable; bone graft; fracture; osteoblast; bone tissue engineering
Online: 22 June 2021 (14:22:33 CEST)
The occurrence of bone-related disorders and diseases has increased dramatically in recent years around the world. Demineralized bone matrix (DBM) has been widely used as a bone implant due to its osteoinduction and bioactivity. However, the use of DBM is limited because it is a particulate material, which makes it difficult to manipulate and implant with precision, in addition, these particles are susceptible to migrate to other sites. To address this situation, DBM is commonly incorporated into a variety of carriers. An injectable scaffold has advantages over bone grafts or preformed scaffolds, such as the ability to flow and fill the bone defect. The aim of this research is to develop a DBM carrier with such viscoelastic properties to obtain an injectable bone substitute (IBS). The DBM carrier developed consisted of a PVA/glycerol network cross-linked with borax and reinforced with CaCO3 as a pH neutralizer, porosity generator, and source of Ca. The physicochemical properties were determined by the injectability test, FTIR, SEM, and TGA. Porosity, degradation, bioactivity, possible cytotoxic effect, and proliferation in osteoblasts were also determined. The results show that the developed material has great potential to be used in bone tissue regeneration
ARTICLE | doi:10.20944/preprints202106.0477.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Infective endocarditis; Kidney Transplantation; Survival analysis; graft failure; transplant infectious diseases
Online: 18 June 2021 (11:17:15 CEST)
Purpose: Kidney Transplant Recipients (KTRs) tend to develop infections with characteristic epidemiology, presentation and outcome. While infective endocarditis (IE) is among such complications in KTRs, literature is scarce. We describe the presentation, epidemiology, and factors associated with IE in KTRs. Methods: We performed a retrospective case/control study which included patients from two centers. First episodes of definite or possible IE (Duke criteria), in adult KTRs from January 2007 to December 2018 were included, as well as two controls per case, and followed until December 31 2019. Clinical, biological, and microbiological data and the outcome were collected. Survival was studied using the Kaplan-Meier method. Finally, we searched for factors associated with the onset of IE in KTRs by the comparison of cases and controls. Results: Seventeen cases and 34 controls were included. IE was diagnosed after a mean delay of 78 months after KT, mostly on native valves of the left heart only. Pathogens of digestive origin were most frequently involved (six Enterococcus spp, three Streptococcus gallolyticus and one Escherichia coli), followed by Staphylococci (three cases of S. aureus and S. epidermidis each). Among the risk factors evaluated only age was significantly associated with the occurrence of IE in our study (63.8 years for cases vs. 55.6 years for controls, P=0.03) Patient and death-censored graft survival were greatly diminished five years after IE compared to controls being 50.3% vs. 80.6% (p<0.003) and 29.7% vs. 87.5% (p<0.002), respectively. Conclusion: IE in KTRs is a disease that carries significant risks both for the survival of the patient and the transplant.
ARTICLE | doi:10.20944/preprints201801.0152.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: sinus lift; graft bone; finite element analysis; 3D modeling; dental implant
Online: 17 January 2018 (11:15:00 CET)
Purpose: The aim of the present experimental 3D-finite element study was to evaluate the influence of an augmented sinus lift with an additional inserted bone graft block. The bone graft block stabilizes the implant in addition to conventional augmented bone. We placed the block in three different positions. The implants were loaded with axial force and forces secondary to laterotrusion and protrusion. Material and Methods: A simplified U-shaped 3D finite element model of the upper jaw and a more complex anatomical model of the left maxilla were created. The bone graft block was placed in three positions: in the lower third in contact with the sinus floor, the middle, and the upper third of the implant. Van Mises’ stress distribution was calculated and analyzed for the different models. We also compared the complex anatomical model with the simplified one. Results: The position of the bone graft block significantly influences the magnitude of stress distribution. A bone graft block positioned in the upper third or middle of the implant reduces the quantity of stress compared to the reference model without a bone graft block. The low bone graft block position is clearly associated with lower stress distribution in compact bone. We registered no significant differences in stress in compact bone with regard to laterotrusion or protrusion. Conclusions: Maximum values of von Mises stresses in compact bone can be reduced significantly by using a bone graft block. The reduction of stress is nearly the same for positions in the upper third and the middle of the implant. It is much more pronounced when the bone graft block is in the lower third of the implant near the sinus floor, which appeared to be the best position in the present study.
REVIEW | doi:10.20944/preprints202203.0059.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: vitamin D; calcifediol; cailcitriol; graft-versus-host disease; vitamin D receptor (VDR)
Online: 3 March 2022 (10:02:45 CET)
The different cell subsets of the immune system express vitamin D receptor (VDR). Through VDR, vitamin D exerts different functions which influences on immune responses, as previously shown in different preclinical models. Based on this background, retrospective studies have explored the impact of vitamin D levels on the outcome of patients undergoing allogeneic hematopoietic stem cell transplantation, showing that vitamin D deficiency is related to an increased risk of complications, especially graft-versus-host disease. These results have been confirmed in a prospective cohorts trial, although further studies are required to confirm this data. In addition, the role of vitamin D on the treatment of hematologic malignancies has also been explored. Considering this dual effect both on the immune system as well as on tumor cells in patients with hematologic malignancies, vitamin D might be useful in this setting both to decrease graft-versus-host disease and relapse rates.
ARTICLE | doi:10.20944/preprints201902.0131.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: Platelet-rich fibrin, A-PRF, Gingival graft harvesting, Healing, Periodontal plastic surgery
Online: 14 February 2019 (10:29:29 CET)
This study aimed to investigate the healing effect of advanced platelet-rich fibrin (A-PRF) clot membranes in the reduction of palatal wounds resulting from free gingival graft (FGG) harvesting, in the re-epithelization rate and in the pain experience after surgery. Twenty-five patients requiring soft tissue augmentation (gingival recession coverage or keratinized gingiva augmentation) participated in this prospective randomized clinical study. After FGG harvesting, the test group (n=14) received A-PRF clot membranes at the palatal wound and the control group (n=11) a gelatin sponge. Epithelialization rate of the palatal wound, wound healing area, correspondent percentage of reduction and post-surgical pain experience were assessed. The follow-up period was 90 days. There was a significantly higher reduction of the palatal wound area in the A-PRF group vs. the control group, at 7 (p<0.001), 14 (p=0.009) and 30 days (p<0.001) follow-up. The maximum difference between groups was attained at 30 days (91.5% for A-PRF vs. 59.0% for the control group). At 14 days a significant difference in the proportion of patients showing total epithelization was found: 64.3% for A-PRF vs. 9.1% for the control group (p=0.012). At 90 days, both groups showed total recovery. Overall, the control group experienced a higher level of pain and discomfort until the 14th day, being significantly higher on the second day (p=0.013). The results suggest that A-PRF membranes haste the healing process by promoting a greater reduction along the recovery period and an apparent less painful postoperative period.
REVIEW | doi:10.20944/preprints201803.0005.v1
Subject: Chemistry And Materials Science, Polymers And Plastics Keywords: chitin; chitosan; derivatization; controlled functionalization, click chemistry; graft copolymer; cyclodextrin; dendrimer; ionic liquids
Online: 1 March 2018 (07:13:47 CET)
The functionalization of polymeric substances is of great interest for the development of innovative materials for advanced applications. For many decades, the functionalization of chitosan has been a convenient way to improve its properties with the aim to prepare new materials with specialized characteristics. In the present article, we summarize the latest methods for the modification and derivatization of chitin and chitosan, trying to introduce specific functional groups under experimental conditions, which allow a control over the macromolecular architecture. This is motivated because an understanding of the interdependence between chemical structure and properties is an important condition for proposing innovative materials. New advances in methods and strategies of functionalization such as click chemistry approach, grafting onto copolymerization, coupling with cyclodextrins and reactions in ionic liquids are discussed.
REVIEW | doi:10.20944/preprints202305.0712.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: scaffold; cell therapy; tissue-engineered vascular graft; clinical translation of tissue-engineered vascular grafts
Online: 10 May 2023 (08:35:23 CEST)
Cardiovascular diseases remain the leading cause of mortality worldwide. Although new therapies are actively being developed and used for cardiovascular pathologies, these attempts have not significantly decreased mortality rates. Regenerative medicine has made enormous progress and set promising approaches over the past half-century. However, since autologous (donor-derived) vascular grafts are lacking, an alternative prosthesis must be constructed for cardiovascular disease patients. In vascular tissue manufacturing and regenerative medicine, scientists seek to improve this significant clinical challenge using bio-fabrication techniques combining additive manufacturing, biomaterials science, and advanced cellular biology. In the last few decades, many improvements and changes in various approaches have helped develop bioengineered concepts that reflect native blood vessels’ structure and function. However, numerous challenges must be overcome to clinically translate the next generation of tissue-engineered vascular transplants. This review provides update on the cell sources, scaffold essential for cardiovascular tissue engineering, and tissue engineering approaches as prospective options for curative therapy for blood vessel disease.
REVIEW | doi:10.20944/preprints202008.0071.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: review; biomaterials; polyethylene; UHMWPE; ACL; Ligament; tendon; plasma treatment; surface modification; synthetic graft; bioactive glass
Online: 4 August 2020 (03:27:46 CEST)
The selection of biomaterials for biomedical application is a significant challenge. In the last few decades, various bioabsorbable and stable biopolymers have been applied for use as biomedical devices in orthopedic applications. Ultra-high molecular weight polyethylene (UHMWPE) has been extensively used in medical implants, notably in the bearings of hip, knee, and other joint prostheses, owing to its biocompatibility and high wear resistance. For the ACL graft, synthetic UHMWPE is an ideal candidate due to its biocompatibility and its extremely high tensile strength. Despite the appeal of new advanced materials such as carbon fiber, poly-ether-ether ketone, and other load-bearing materials, UHMWPE remains a primary load-bearing candidate material for ACL reconstructions because of its extremely high strength, the simplicity of the fabrication process, its biocompatibility, and low friction. However, some significant problems are observed in UHMWPE based implants, such as wear debris, and oxidative degradation due to the generation of free radicals when exposed to irradiation with gamma rays for grafting or sterilization. Various innovative methodologies have been developed to resolve those problems and enhance the properties of UHMWPE. In this review, we will explore in detail the methods for surface functionalization of UHMWPE and will apply these findings to the case study of UHMWPE for Anterior Cruciate Ligament repair.
ARTICLE | doi:10.20944/preprints202205.0246.v1
Subject: Biology And Life Sciences, Horticulture Keywords: oriental melon; squash; graft; exogenous naphthylacetic acid; transcriptomic analysis; endogenous hormone; signal transduction; ROS scavenging; vascular bundle formation
Online: 19 May 2022 (03:22:20 CEST)
The plant graft healing process is an intricate development influenced by numerous endogenous and environmental factors. This process involves the histological changes, physiological and biochemical reactions, signal transduction, and hormone exchanges in the grafting junction. Studies have shown that applying exogenous plant growth regulators can effectively promote the graft healing process and improve the quality of grafted plantlets. However, the physiological and molecular mechanism of graft healing formation remains unclear. In our present study, transcriptome changes in the melon and cucurbita genomes were analyzed between control and NAA treatment, and we provided the first view of complex networks to regulate graft healing under exogenous NAA application. The results showed that the exogenous NAA application could accelerate the graft healing process of oriental melon scion grafted onto squash rootstock through histological observation, increase the SOD, POD, PAL, and PPO activities during graft union development and enhance the contents of IAA, GA3, and ZR except for the IL stage. The DEGs were identified in the plant hormone signal-transduction, phenylpropanoid biosynthesis, and phenylalanine metabolism through transcriptome analysis of CK vs. NAA at the IL, CA, and VB stage by KEGG pathway enrichment analysis. Moreover, the exogenous NAA application significantly promoted the expression of genes involved in the hormone signal-transduction pathway, ROS scavenging system, and vascular bundle formation.
ARTICLE | doi:10.20944/preprints201810.0321.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: amniotic membrane; epithelialization; inflammation; ocular surface disorders; anti-fibrotic action, amniotic membrane eye drop, amniotic membrane graft transplantation
Online: 15 October 2018 (14:35:06 CEST)
The aim of this study is to emphasize on the clinical uses of amniotic membrane (AM) in multiple ocular disorders. AM possesses many properties including promotion of epithelialization, anti-fibrotic, anti-apoptotic, anti-angiogenic properties. Epithelial wound healing on the eye surface is promoted due to several epidermal and keratocyte growth factors as well as by its anti-inflammatory and anti-scarring effects due to interleukin-10, interleukin-1 receptor antagonists and inhibition of transforming growth factor- beta (TGF-β) signal transduction by AM in the corneal and conjunctival fibroblasts respectively. It plays a crucial role by functioning as a substitute of basement membrane (BM) and as a temporary graft material. It is not only being used as an eye graft but also its extract can be used as an eye drop for corneal and external eye diseases. So its proper preparation, preservation and clinical application can bring a revolutionary change in the treatment of different ocular disorders.
REVIEW | doi:10.20944/preprints201810.0307.v1
Subject: Medicine And Pharmacology, Ophthalmology Keywords: Keywords: amniotic membrane; epithelialization; inflammation; ocular surface disorders; anti-fibrotic action, amniotic membrane eye drop, amniotic membrane graft transplantation.
Online: 15 October 2018 (12:06:21 CEST)
Abstract: The aim of this study is to emphasize on the clinical uses of amniotic membrane (AM) in multiple ocular disorders. AM possesses many properties including promotion of epithelialization, anti-fibrotic, anti-apoptotic, anti-angiogenic properties. Epithelial wound healing on the eye surface is promoted due to several epidermal and keratocyte growth factors as well as by its anti-inflammatory and anti-scarring effects due to interleukin-10, interleukin-1 receptor antagonists and inhibition of transforming growth factor- beta (TGF-β) signal transduction by AM in the corneal and conjunctival fibroblasts respectively. It plays a crucial role by functioning as a substitute of basement membrane (BM) and as a temporary graft material. It is not only being used as an eye graft but also its extract can be used as an eye drop for corneal and external eye diseases. So its proper preparation, preservation and clinical application can bring a revolutionary change in the treatment of different ocular disorders.
ARTICLE | doi:10.20944/preprints202305.0216.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: autogenous dentin particulate; bone regeneration; dental biomaterials; granules; grow factors; high-speed grinder; low-speed grinder; osteoclasts; tooth graft; tooth transformer
Online: 4 May 2023 (07:44:16 CEST)
Background: In regenerative dentistry the graft material influences the success. It should act as an osteoconductive scaffold, providing a mineral substrate during resorption and inducing the activity of osteoinductive cells capable of producing new bone, platelet growth factors, and cell differentiation factors inducing the differentiation of undifferentiated mesenchymal cells into. Given that dentin shares many biochemical characteristics with bone tissue, it has recently attracted considerable interest as a biomaterial for bone repair. The aim of this study is to compare two grinder types in order to determine the optimal method for producing dentinal particles using a mechanical grinder. Materials and methods: A sample of 40 natural human teeth without restorations, prostheses or root canal treatments was used and divided into two groups subjected to two different grinder speeds (high-speed and low-speed). The high-speed showed a greater dispersion (53.5+-9.89% of the tooth) due to the pulverisation (highly thin granules) of part of the tooth. The low-speed grinder does not pulverize the dentin and the percentage of tooth loss is 9.16+/-2.34%. Conclusion: The low-speed gringer allows to save a major part of the tooth and to have a maximum quantity of graft material but requires more time. Further studies must be promoted to optimise the grinding procedures.
REVIEW | doi:10.20944/preprints201807.0237.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: TRPM7, kinase, inflammation, lymphocytes, calcium signalling, SMAD, TH17, hypersensitivity, regulatory T cells, thrombosis, graft versus host disease, T cells, innate immunity
Online: 13 July 2018 (14:14:56 CEST)
The enzyme-coupled transient receptor potential channel subfamily M member 7, TRPM7, has been associated with immunity and immune cell signalling. Here, we review the role of this remarkable signalling protein in lymphocyte proliferation, differentiation, activation and survival. We also discuss its role in mast cell, neutrophil and macrophage function and highlight the potential of TRPM7 to regulate immune system homeostasis. Further, we shed light on how the cellular signalling cascades involving TRPM7 channel and/or kinase activity culminate in pathologies as diverse as allergic hypersensitivity, arterial thrombosis, and graft versus host disease (GVHD), stressing the need for TRPM7 specific pharmacological modulators.
CASE REPORT | doi:10.20944/preprints202304.0775.v1
Subject: Medicine And Pharmacology, Dermatology Keywords: facial rejuvenation; Stromal Vascular Fraction; adipose derived mesenchymal stem cells; autologous adipose tissue graft; Superficial Enhanced Fluid Fat Injection; clinical regeneration applications
Online: 23 April 2023 (05:01:28 CEST)
Background: The ageing process starts in the center of the face, in the periocular region and around the mouth, with a combination of volume loss and tissue descent, wrinkles deepen, and loss of skin structure and quality. Recently, several studies proved the efficacy of therapies based on the autologous adipose tissue grafting that leverages the properties of stromal vascular fraction (SVF) and adipose derived mesenchymal stem cells (ADSCs) to accelerate the regenerative processes of the skin. This study aimed to verify the ability of the guided Superficial Enhanced Fluid Fat Injection (SEFFI) in the facial area to correct volume loss and skin aging and proved the very low rate of complications of this standardized procedure . Methods: we retrospectively collected data from 2,365 procedures performed in Italian centers between 2019 and 2021. Guided SEFFI was performed alone or combined with cosmetic treatments, including the use of hyaluronic acid filler, suspension threads, synthetic calcium hydroxylapatite, botulin toxin, and microneedling. Results: SEFFI was used alone in more than 60% of the patients, and in all face areas. In about one tenth of patients SEFFI was combined with botulin toxin treatment or hyaluronic acid filling. Other procedures were used more rarely. Ecchymosis in the donor or injection sites was the most frequent event, and yet observed in only 14.2% and 38.6% of patients, respectively. Conclusions: The SEFFI technique is standardized and minimally invasive, leading to very few complications. It can be a promising antiaging medical treatment that combines effectiveness, safety, and simplicity.
ARTICLE | doi:10.20944/preprints202206.0242.v1
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: nerve repair; median nerve; rat; autologous nerve graft; muscle-in-vein conduit; extracorporeal shock wave therapy; grasping test; gait analysis; CatWalk, nerve regeneration
Online: 17 June 2022 (03:17:43 CEST)
Investigations reporting positive effects of Extracorporeal Shock Wave Therapy (ESWT) on nerve regeneration are limited to the rat sciatic nerve model. The effects of ESWT on muscle-in-vein conduits (MVCs) have also not been investigated yet. This study aimed to evaluate the effects of ESWT after repair of the rat median nerve with either autografts (ANGs) or MVCs. In male Lewis rats, a 7-mm segment of the right median nerve was reconstructed either with an ANG or MVC. For each reconstructive technique, one group of animals received one application of ESWT while the other rats served as controls. Animals were observed for 12 weeks and nerve regeneration was assessed via computerized gait analysis, the grasping test, electrophysiological evaluations and histological quantification of axons, blood vessels and lymphatic vasculature. Here we provide for the first time a comprehensive analysis of ESWT effects on nerve regeneration in a rat model of median nerve injury. Furthermore, this study is among the first reporting the quantification of lymphatic vessels following peripheral nerve injury and reconstruction in vivo. While we found no significant direct positive effects of ESWT on peripheral nerve regeneration, results following nerve repair with MVCs were significantly inferior to those after ANG repair.
ARTICLE | doi:10.20944/preprints202305.0700.v1
Subject: Medicine And Pharmacology, Hematology Keywords: allogeneic hematopoietic stem cell transplantation; autoimmune limbic encephalitis; cyclo-phosphamide; regulatory T cells; CD25; Foxp3; IL-6; fever; acute graft-versus-host disease; cyto-kine-release syndrome
Online: 10 May 2023 (07:46:24 CEST)
Autoimmune limbic encephalitis (LE) is a rare, but devastating complication of allogeneic hem-atopoietic stem cell transplantation (HSCT). There is currently limited evidence describing the risk factors, laboratory features, and underlying mechanisms of this neurologic adverse event. We retrospectively reviewed available clinical, imaging, and laboratory data from adult patients with hematological malignancies who underwent haploidentical HSCT with cyclophosphamide (PTCy) at Chungnam National University Hospital from June 2016 to May 2020. Patients who developed LE were compared to those who did not based on clinical assessment, serum inflam-matory biomarkers, and reconstitution of various T cell populations. Of 35 patients, four devel-oped LE. There were no differences in patient demographics, donor demographics, or treatment conditions between patients that did and did not develop LE. Overall, patients with LE had worse clinical outcomes and overall survival than those without. In addition, they tended to have higher markers of systemic inflammation in the early post-transplant period, including fever, C-reactive protein (CRP), and cytokines. Remarkably, baseline interleukin-6 levels before HSCT were found to be higher in patients who developed LE than those who did not. In addition, analysis of T cell subsets showed impaired expansion of CD25+FOXP3+ regulatory T (Treg) cells in LE compared to non-LE patients despite appropriate reconstitution of the total CD4+ T cell population. Patients that developed LE within the first 30 days of HSCT were likely to have high serum IL-6 among other inflammatory cytokines coupled with suppression of regulatory T cell differentiation. Further work is needed on the mechanisms underlying impaired Treg expansion following HSCT and potential therapies.