Search Results (1,016)

The treatment of type 1 diabetes through pancreatic islet transplantation faces significant limitations, including donor organ shortages and poor islet survival due to post-transplantation loss of extracellular matrix support and inadequate vascularization. Developing biocompatible scaffolds that mimic the native islet microenvironment could substantially improve transplantation outcomes. This study aimed to create and evaluate decellularized (DCL) matrices from porcine organs as potential platforms for islet transplantation. Porcine lung and pancreatic tissues were decellularized using four different protocols combining detergents (Triton X-100, SDS and SDC) with optimized incubation times. The resulting matrices were characterized through DNA quantification and histological staining (H&E and Van Gieson). Islet viability was assessed in vitro using Live/Dead staining after 3 and 7 days of culture on the matrices. In vivo biocompatibility was evaluated by implanting matrices into rat omentum or peritoneum, with histological analysis at 1-, 4-, and 8 weeks post-transplantation. Protocols 3 (for lung tissue) and 4 (for pancreas tissue) demonstrated optimal decellularization efficiency with residual DNA levels below 8%, while preserving the collagen and elastin networks. In vitro, islets cultured on decellularized lung matrix had maintained 95% viability by day 7, significantly higher than the controls (60%) and pancreatic matrix (83%). The omentum showed superior performance as an implantation site, exhibiting minimal inflammation and fibrosis compared to the peritoneum sites throughout the 8-week study period. These findings establish DCL as a promising scaffold for islet transplantation due to its superior preservation of ECM components and excellent support of islet viability. This work provides a significant step toward developing effective tissue-engineered therapies for diabetes treatment. Full article

Over the past century, the understanding of type 1 diabetes mellitus (T1DM) has evolved significantly, transitioning from a fatal metabolic disorder to a well-characterized autoimmune disease. This review explores the historical developments and scientific milestones that have reshaped the perception of T1DM, highlighting key discoveries and shifts in medical paradigms. Methods: A comprehensive narrative review was conducted, examining literature spanning from ancient medical texts to contemporary research up to 2024. Emphasis was placed on pivotal moments such as the discovery of insulin in 1921, the recognition of autoimmune mechanisms in the 1970s, and recent advancements in immunotherapy. Results: The reclassification of T1DM as an autoimmune disease was supported from multiple lines of evidences including the presence of islet cell autoantibodies, the identification of lymphocytic infiltration in pancreatic islets, and the associations of the disease with certain HLA class II alleles. The development of animal models and large-scale cohort studies facilitated the establishment of disease staging and risk prediction models. Notably, the approval of immunotherapies like teplizumab underscores the translational impact of these scientific insights. Conclusions: The historical trajectory of T1DM exemplifies the dynamic nature of medical knowledge and the interplay between clinical observations and scientific research. Recognizing these developments enhances our comprehension of disease mechanisms and informs current approaches to diagnosis and treatment. Full article

Small (monomeric) GTP-binding proteins (smgs; Cdc42 and Rac1) play requisite roles in islet beta cell function, including glucose-stimulated insulin secretion. In addition, emerging evidence suggests that sustained (constitutive) activation of smgs (e.g., Rac1) culminates in the genesis of islet beta cell dysfunction under the duress of chronic hyperglycemia. It is noteworthy that functions (i.e., activation–deactivation) of smgs in many cells, including the islet beta cell, have been shown to be under the regulatory control of at least three factors, namely the guanine nucleotide exchange factors (GEFs), the GTPase-activating proteins (GAPs), and the GDP-dissociation inhibitors (GDIs). The overall objective of this review is to highlight our current understanding of the regulatory roles of the RhoGDIβ-Rac1-CARD9 signalome in the pathology of beta cell dysfunction under chronic hyperglycemic stress. For brevity, this review is structured by an overview of smgs and their regulatory proteins/factors in the beta cell, followed by a discussion of potential roles of the RhoGDIβ-Rac1-CARD9 axis in the onset of cellular dysfunction under the duress of metabolic stress. Overall conclusions, potential knowledge gaps, and opportunities for future research in this field of islet biology are highlighted in the last section. Full article

Background: Uric acid has been proposed as a diabetogenic factor while its effect on pancreatic β cell function remains elusive. This study aimed to explore the impact of uric acid levels on β cell function and delineate its underlying molecular mechanisms. Methods: Both in vivo hyperuricemia diet-induced mouse models and in vitro pancreatic β cell models were utilized. Results: A progressive decrease in glucose-stimulated insulin secretion and increase in β cell apoptosis were observed in the hyperuricemia diet-induced mouse model, and these could be effectively restored by urate-lowering therapy. The dose- and time-dependent direct effects of uric acid on β cell apoptosis and insulin secretion were further confirmed in both INS-1E cells and primary isolated islets. Mechanistically, the primary role of expression of the endoplasmic reticulum stress marker C/EBP homologous protein (CHOP) was detected by RNA sequencing, and the inflammatory factor NLRP3 and pro-apoptotic genes were significantly upregulated by uric acid treatment. Conclusions: Together, our findings indicate a direct crosstalk between uric acid and β cells via CHOP/NLRP3 pathway, providing a new understanding of the diabetogenic effect of uric acid. Full article

Type 1 diabetes is classified into three clinical subtypes: fulminant type 1 diabetes, acute-onset type 1 diabetes, and slowly progressive type 1 diabetes, also known as latent autoimmune diabetes in adults. Among these, the fulminant and slowly progressive forms may develop in association with pregnancy and are herein collectively referred to as “pregnancy-associated type 1 diabetes”. Fulminant type 1 diabetes can manifest suddenly during pregnancy, often accompanied by ketoacidosis, posing a significant risk to both the mother and the fetus. Early diagnosis and treatment are, therefore, critical. In pregnant women with no prior history of diabetes who present with marked hyperglycemia (≥288 mg/dL) but relatively low HbA1c levels (<8.7%), fulminant type 1 diabetes should be suspected, and insulin therapy should be initiated immediately. Conversely, women diagnosed with gestational diabetes who test positive for anti-islet autoantibodies are at high risk of developing slowly progressive type 1 diabetes postpartum. For these patients, regular monitoring of blood glucose levels, HbA1c, and endogenous insulin secretion is essential for early detection and management. Full article

Background: The early detection of type 1 diabetes (T1D) through screening for major islet autoantibodies is receiving increasing attention as a public health strategy, exemplified by the recent implementation of a pilot pediatric screening program in Italy. The transition from research-based screening to large-scale population initiatives needs automated and standardized assays that are capable of processing extensive sample volumes. Hence, this study aimed to evaluate the analytical performance and comparability of a fully automated chemiluminescence immunoassay (CLIA) compared to a conventional enzyme-linked immunosorbent assay (ELISA) for the detection of three classes of major islet antibodies—anti-GAD (GADA), anti-IA-2 (IA-2A), and anti-ZnT8 (ZnT8A). Methods: A total of 104 serum specimens were analyzed for each autoantibody using both ELISA (RSR and Medyzim, DYNES, DSX) and CLIA (MAGLUMI 800). Assay precision and linearity were assessed through intra-assay variability studies and dilution protocols. Methods agreement was evaluated with Passing–Bablok regression, Spearman’s correlation, Bland–Altman analysis, and Cohen’s kappa statistics. Results: The CLIA showed good precision and excellent linearity across clinically relevant concentration ranges of all islet antibodies. Correlation coefficients and categorical agreement between CLIA and ELISA were high (r > 0.96 and Cohen’s kappa >0.8 for all), with ZnT8A exhibiting the highest concordance. However, proportional biases were found, as CLIA systematically underestimated GADA and ZnT8A levels, while overestimated IA-2A compared to the ELISA. Conclusions: The CLIA displayed satisfactory precision and agreement with ELISA for GADA, IA-2A, and ZnT8A detection. Our findings support the use of these automated immunoassays in large-scale population initiatives for diagnosing T1D, but we also highlight the need for further efforts to achieve better inter-assay harmonization. Full article

Type 1 diabetes (T1D) is caused by autoimmune-mediated destruction of pancreatic β-cells, resulting in insulin deficiency. While islet transplantation presents a potential therapeutic approach, its clinical application is impeded by limited donor availability and the risk of immune rejection. This study proposes an innovative islet encapsulation strategy that utilizes decellularized porcine pancreatic extracellular matrix (pECM) as the sole biomaterial to engineer bioactive, immunoprotective microcapsules. Rat islets were encapsulated within pECM-based microcapsules using the electrospray technology and were compared to conventional alginate-based microcapsules in terms of viability, function, and response to hypoxic stress. The pECM microcapsules maintained a spherical morphology, demonstrating mechanical robustness, and preserving essential ECM components (collagen I/IV, laminin, fibronectin). Encapsulated islets exhibited sustained viability and superior insulin secretion over a two-week period compared to alginate controls. The expression of key β-cell transcription factors (PDX1, MAFA) and structural integrity were preserved. Under hypoxic conditions, pECM microcapsules significantly reduced islet apoptosis, improved structural retention, and promoted functional recovery, likely due to antioxidant and ECM-derived cues inherent to the pECM. In vivo transplantation in immunocompetent mice confirmed the biocompatibility of pECM microcapsules, with minimal immune responses, stable insulin/glucagon expression, and no adverse systemic effects. These findings position pECM-based microencapsulation as a promising strategy for creating immunoprotective, bioactive niches for xenogeneic islet transplantation, with the potential to overcome current limitations in cell-based diabetes therapy. Full article

Background/Objectives: 5-Aminolevulinic acid (5-ALA) is a biosynthetic precursor of heme that induces heme oxygenase-1 (HO-1). Therapeutic induction of HO-1 has shown effectiveness in various autoimmune disease models, including type 1 diabetes (T1D). However, the efficacy of 5-ALA as an HO-1 inducer in T1D models remains unexplored. This study aimed to investigate the therapeutic efficacy of oral 5-ALA administration in preventing autoimmune diabetes development in nonobese diabetic (NOD) mice. Methods: We evaluated diabetes incidence, levels of insulin autoantibody, and severity of insulitis in 5-ALA-treated and control NOD mice. HO-1 expression of dendritic cells in the pancreatic islets and spleen of 5-ALA-treated NOD mice was measured. The IFN-γ/IL-17 of islet-infiltrating T cells and IL-10/IL-12 productions of dendritic cells in the spleen of 5-ALA-treated NOD mice were assessed. We stimulated islet antigen-specific CD4⁺ T cells with islet antigen-pulsed dendritic cells in the presence of 5-ALA and examined the proliferation of the T cells. Finally, we adoptively transferred islet antigen-specific CD4⁺ T cells into 5-ALA-treated, immunodeficient NOD-Rag1 knockout mice, and diabetes incidence in recipients was determined. Results: Oral 5-ALA treatment did not significantly impact diabetes incidence, levels of insulin autoantibody, and insulitis. No significant difference was observed in HO-1 expression in dendritic cells and cytokine production of T cells and dendritic cells. Similarly, there was no significant difference in the proliferation of islet antigen-specific CD4⁺ T cells in vitro and diabetes induction in transfer experiments. Conclusions: Oral administration of 5-ALA has a limited effect on suppressing the development of autoimmune diabetes in NOD mice. Full article

Background: Hypothermia, occurring when core temperature drops below 35 °C, can lead to death when the body’s heat loss exceeds its heat production. This study investigates two hypothermia-related deaths, exploring the utility of immunohistochemistry, specifically focusing on chromogranin A (CgA) as a potential diagnostic tool. The aim is to assess whether CgA expression in neuroendocrine tissues can be considered a reliable indicator of premortem stress response in fatal hypothermia cases. Case Presentation: In the first case, a 67-year-old man was found on a snowy road 24 h after his disappearance. The autopsy revealed cold-induced skin lesions, gastric hemorrhages, and cerebral and pulmonary edema. Positive CgA immunostaining was observed in the pancreatic islets and adrenal medulla. In the second case, a 49-year-old man was found dead in a wooded area with indications of suicide. Both cases were examined with attention to macroscopic findings and histological samples from major neuroendocrine organs. As in previous cases, CgA immunostaining was positive in the pancreatic islets and adrenal medulla. Staining intensity was moderate to strong, consistent with heightened neuroendocrine activity, supporting the hypothesis of systemic stress prior to death. Conclusions: Although CgA is a potentially valuable adjunct in hypothermia diagnosis, careful consideration of cadaveric preservation is emphasized, particularly when bodies are preserved before autopsy. Further studies with larger sample sizes are needed to confirm its diagnostic specificity and to distinguish true pathological patterns from postmortem artifacts. Full article

Type 1 diabetes (T1D) results from the autoimmune destruction of insulin-producing β-cells. The regeneration of durable insulin-producing β-cells remains a critical challenge. This study investigated the regenerative potential of Fraction-B (FB), a catfish skin-derived preparation rich in growth factors, in a T1D rat model to regenerate active β-cells. Sprague Dawley rats with T1D caused by streptozotocin injection received daily intraperitoneal injections of FB for 8 weeks. FB treatment significantly reduced blood glucose to a level close to that of normal control animals, increased serum insulin and C-peptide, and restored pancreatic insulin content. Histopathological and immunohistochemical analyses confirmed the regeneration of insulin-producing β-cells in pancreatic islets. FB treatment also improved diabetes-related health issues through a reduction in inflammation and oxidative stress, and an improvement in lipid profiles without toxicity or side effects. The regenerated β-cells remained functional for 48 weeks without the use of immunosuppressants, until the animals were sacrificed. These findings suggest FB treatment to be a promising procedure for translational research into T1D treatment. Full article

Background/Objectives: Vitexin and isovitexin are bioactive flavonoids with promising pharmacological effects; however, they have poor bioavailability. Microencapsulation with biodegradable polymers is a promising strategy for improving their stability, bioavailability, and biocompatibility. This study aimed to optimize the formulation parameters to obtain microspheres with desired properties in terms of size, loading ratio, and vitexin–isovitexin release. Methods: Microspheres were prepared using alginate as the core matrix and a chitosan outer layer. A Design of Experiment approach using response surface methodology was employed. The hypoglycemic effects of the obtained microspheres were evaluated. Results: The formulation using 1.17% low-viscosity alginate, 7.60% calcium chloride, 5.78% Tween 80, and 5.00% Span 80 resulted in microspheres with optimal mean size (10.78 µm), high loading ratio (22.45%) and encapsulation efficiency (68.92%). The in vitro release of vitexin–isovitexin from microspheres was completed within 24 h in controlled manner. The microspheres were found to be non-toxic in vivo and exhibited hypoglycemic effects after 21 days at doses equivalent to 30 and 60 mg/kg of vitexin–isovitexin. The potential mechanisms might involve increasing the size of Islets of Langerhans and improving pancreatic β-cell function and insulin resistance, as observed in alloxan-induced diabetic mice. Conclusions: This work successfully developed alginate–chitosan-based microspheres for the controlled release of vitexin–isovitexin while maintaining their bioactivities. Full article

Hyperglycemia during fetal development disturbs extracellular matrix (ECM) synthesis and deposition patterns, which disrupts organogenesis and adult organ function. Although the ECM cooperates in pancreas development, little is known about the effects of hyperglycemia on the pancreatic ECM during development. This study investigates the effect of severe maternal hyperglycemia on ECM composition and endocrine pancreas development in E19.0 mouse fetuses. Deposition patterns of pan-laminin, laminin (alpha 1 and gamma 1 chains) and integrin alpha 3 were evaluated by immunostaining. The proliferative index of islet cells and alpha and beta cell distribution were evaluated by PCNA, glucagon and insulin immunostaining, respectively. Pdx1 and Pax4 expressions were analyzed by RT-qPCR. While for pan-laminin and laminin (alpha1 and gamma1 chains) deposition was weaker in the endocrine pancreas of hyperglycemic mothers’ fetuses, integrin alpha 3 deposition in the basement membrane was increased. The proliferative index of endocrine cells was lower in the hyperglycemic group, while the beta-cell area was increased. In addition, there was a tendency towards lower Pdx1 and increased Pdx4 expression. These data suggest that maternal hyperglycemia alters fetal endocrine pancreas morphogenesis by modifying peri-islet basement membrane molecule patterns, promoting a decrease in endocrine cell proliferation associated with changes in the expression of important growth factors for the beta cells differentiated and the proliferative state. Full article

Type 2 diabetes, a widespread metabolic disorder, is characterized by hyperglycemia and insulin resistance. Xylose-oligosaccharide, a functional oligosaccharide, has shown potential in mitigating hyperglycemia. This study established a type 2 diabetes mouse model via a high-fat diet and streptozotocin administration to investigate the effects of two xylose-oligosaccharide doses (20 and 60 mg/kg/day). Both doses were observed to regulate lipid metabolism, decrease inflammation, and alleviate damage to the liver, kidneys, and islets. Additionally, xylose-oligosaccharide corrected diabetes-induced intestinal microbiota imbalances by increasing Bacteroides and Proteobacteria while decreasing Firmicutes. Notably, the 60 mg/kg/day dose was more effective in enhancing glucose tolerance and reducing insulin resistance compared to the 20 mg/kg/day dose. These results suggested that xylose-oligosaccharide had hypoglycemic effects, reduced insulin resistance and oxidative stress, possessed anti-inflammatory properties, and modulated intestinal microbiota. Thus, xylose-oligosaccharide shows promise as a functional food for managing type 2 diabetes. Full article

Aim: Myricetin, a natural bioflavonoid, is reported as an anti-diabetic agent since it possesses the ability to inhibit α-glucosidase activity, stimulate insulin action and secretion, manage ROS, and prevent diabetes complications. Myricetin was identified as a new insulin secretagogue that enhances glucose-stimulated insulin secretion and seems like a better antidiabetic drug candidate. Here, we explored the insulinotropic mechanism(s) of myricetin in vitro in mice islets and in silico. Methods: Size-matched pancreatic islets were divided into groups and incubated in the presence or absence of myricetin and agonists/antagonists of major insulin signaling pathways. The secreted insulin was measured by ELISA. Molecular docking studies were performed with the key player of insulin secretory pathways. Results: Myricetin dose-dependently enhanced insulin secretion in isolated mice islets, and its insulinotropic effect was exerted at high glucose concentrations distinctly different from glibenclamide. Myricetin-induced insulin secretion was significantly inhibited using the diazoxide. Furthermore, myricetin amplified glucose-induced insulin secretion in depolarized and glibenclamide-treated islets. Myricetin showed an additive effect with forskolin- and IBMX-induced insulin secretion. Interestingly, H89, a PKA inhibitor, and MAY0132, an Epac-2 inhibitor, significantly inhibited myricetin-induced insulin secretion. The in silico molecular docking studies further validated these in vitro findings in isolated pancreatic islets. Conclusions: Myricetin, a potential natural insulin secretagogue, amplifies glucose-induced insulin secretion via the cAMP-PKA-Epac-2 signaling pathway. Full article

Background/Objectives: Previous studies have shown that unformulated extracts of Passiflora ligularis leaves exhibit promising antidiabetic activity. This research aimed to demonstrate that formulating the extract into a self-emulsifying drug delivery system (PLE-SEDDS) enhanced its antidiabetic activity in a high-fat-diet/streptozotocin-induced diabetic mouse model. Methods: Blood glucose levels (BGLs) of diabetic mice were monitored during 21 days of oral administration of P. ligularis extract (PLE) and PLE-SEDDS. Control groups included metformin (positive control), vehicle, and SEDDS vehicle (negative controls). The animals underwent an oral glucose tolerance test (OGTT). The oxidative stress markers superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation quantified by malondialdehyde (MDA) levels were measured in the kidney, liver, and pancreas, complemented with histopathological analysis. Additionally, plasma lipid profile parameters were evaluated. Results: The PLE-SEDDS formulation demonstrated superior efficacy compared to the PLE extract in improving antidiabetic outcomes. Animals treated with PLE-SEDDS exhibited a minimal increase in blood glucose levels (11.5%) during the OGTT, compared to 27.4% with PLE and over 77% in the vehicle groups. PLE-SEDDS also showed greater enhancement of SOD and CAT activity, along with a more pronounced reduction in MDA levels, indicating stronger protection against oxidative stress. Histological analysis revealed significant preservation of pancreatic islets, and lipid profile analysis showed greater reductions in triglycerides, cholesterol, and LDL-C, alongside increased HDL-C levels. Conclusions: Altogether, these findings suggest that PLE-SEDDS exhibits superior antihyperglycemic, hypolipidemic, and antioxidant effects compared to the unformulated extract, making this novel formulation a promising option for treating type 2 diabetes mellitus. Full article