Search Results (305)

Background/Objectives: Diabetes mellitus (DM) is an increasingly prevalent endocrine disorder affecting humans and companion animals. Type 1 DM (T1DM) and type 2 DM (T2DM) are well characterized in humans, and canine DM most often resembles T1DM, marked by insulin dependence and β-cell destruction. Conversely, feline DM shares key features with human T2DM, including insulin resistance, obesity-related inflammation, and islet amyloidosis. This review provides a comprehensive comparative analysis of antidiabetic therapies in humans, dogs, and cats, focusing on three core areas: disease pathophysiology, pharmacological and delivery strategies, and translational implications. In human medicine, a wide array of insulin analogs, oral hypoglycemic agents, and incretin-based therapies, including glucagon-like peptide-1 receptor agonists (liraglutide) and sodium-glucose cotransporter-2 inhibitors (empagliflozin), are available. Veterinary treatments remain limited to species-adapted insulin formulations and off-label use of human drugs. Interspecies differences in gastrointestinal physiology, drug metabolism, and behavioral compliance influence therapeutic efficacy and pharmacokinetics. Recent innovations, such as microneedle patches for insulin delivery and continuous glucose monitoring systems, show promise in humans and animals. Companion animals with naturally occurring diabetes serve as valuable models for preclinical testing of novel delivery platforms and long-acting formulations under real-world settings. While these technologies show potential, challenges remain in regulatory approval and behavioral adaptation in animals. Conclusions: Future research should prioritize pharmacokinetic bridging studies, veterinary-specific formulation trials, and device validation in animal models. By highlighting shared and species-specific characteristics of DM pathogenesis and treatment, this review advocates a One Health approach toward optimized antidiabetic therapies that benefit human and veterinary medicine. Full article

Type 2 diabetes (T2D) is a complex metabolic disease characterized by chronic hyperglycemia due to insulin resistance and inadequate insulin secretion. Beyond the classically implicated organs, emerging evidence highlights the gut as a central player in T2D pathophysiology through its interactions with metabolic organs. The gut hosts trillions of microbes and enteroendocrine cells that influence inflammation, energy homeostasis, and hormone regulation. Disruptions in gut homeostasis (dysbiosis and increased permeability) have been linked to obesity, insulin resistance, and β-cell dysfunction, suggesting multifaceted “Gut-X axes” contribute to T2D development. We aimed to comprehensively review the evidence for gut-mediated crosstalk with the pancreas, endocrine system, liver, and kidneys in T2D. Key molecular mechanisms (incretins, bile acids, short-chain fatty acids, endotoxins, etc.) were examined to construct an integrated model of how gut-derived signals modulate metabolic and inflammatory pathways across organs. We also discuss clinical implications of targeting Gut-X axes and identify knowledge gaps and future research directions. A literature search (2015–2025) was conducted in PubMed, Scopus, and Web of Science, following PRISMA guidelines (Preferred Reporting Items for Systematic Reviews). Over 150 high-impact publications (original research and review articles from Nature, Cell, Gut, Diabetologia, Lancet Diabetes & Endocrinology, etc.) were screened. Data on gut microbiota, enteroendocrine hormones, inflammatory mediators, and organ-specific outcomes in T2D were extracted. The GRADE framework was used informally to prioritize high-quality evidence (e.g., human trials and meta-analyses) in formulating conclusions. T2D involves perturbations in multiple Gut-X axes. This review first outlines gut homeostasis and T2D pathogenesis, then dissects each axis: (1) Gut–Pancreas Axis: how incretin hormones (GLP-1 and GIP) and microbial metabolites affect insulin/glucagon secretion and β-cell health; (2) Gut–Endocrine Axis: enteroendocrine signals (e.g., PYY and ghrelin) and neural pathways that link the gut with appetite regulation, adipose tissue, and systemic metabolism; (3) Gut–Liver Axis: the role of microbiota-modified bile acids (FXR/TGR5 pathways) and bacterial endotoxins in non-alcoholic fatty liver disease (NAFLD) and hepatic insulin resistance; (4) Gut–Kidney Axis: how gut-derived toxins and nutrient handling intersect with diabetic kidney disease and how incretin-based and SGLT2 inhibitor therapies leverage gut–kidney communication. Shared mechanisms (microbial SCFAs improving insulin sensitivity, LPS driving inflammation via TLR4, and aryl hydrocarbon receptor ligands modulating immunity) are synthesized into a unified model. An integrated understanding of Gut-X axes reveals new opportunities for treating and preventing T2D. Modulating the gut microbiome and its metabolites (through diet, pharmaceuticals, or microbiota therapies) can improve glycemic control and ameliorate complications by simultaneously influencing pancreatic islet function, hepatic metabolism, and systemic inflammation. However, translating these insights into clinical practice requires addressing gaps with robust human studies. This review provides a state-of-the-art synthesis for researchers and clinicians, underlining the gut as a nexus for multi-organ metabolic regulation in T2D and a fertile target for next-generation therapies. Full article

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disorder characterized by the destruction of insulin-producing pancreatic beta cells, resulting in lifelong insulin dependence. While genetic susceptibility—particularly human leukocyte antigen (HLA) class II alleles—is a major risk factor, accumulating evidence implicates viral infections as potential environmental triggers in disease onset and progression. This narrative review synthesizes current findings on the role of viral pathogens in T1DM pathogenesis. Enteroviruses, especially Coxsackie B strains, are the most extensively studied and show strong epidemiological and mechanistic associations with beta-cell autoimmunity. Large prospective studies—including Diabetes Virus Detection (DiViD), The environmental determinans of diabetes in the young (TEDDY), Miljøfaktorer i utvikling av type 1 diabetes (MIDIA), and Diabetes Autoimmunity Study in the Young (DAISY)—consistently demonstrate correlations between enteroviral presence and the initiation or acceleration of islet autoimmunity. Other viruses—such as mumps, rubella, rotavirus, influenza A (H1N1), and SARS-CoV-2—have been investigated for their potential involvement through direct cytotoxic effects, immune activation, or molecular mimicry. Interestingly, certain viruses like varicella-zoster virus (VZV) and cytomegalovirus (CMV) may exert modulatory or even protective influences on disease progression. Proposed mechanisms include direct beta-cell infection, molecular mimicry, bystander immune activation, and dysregulation of innate and adaptive immunity. Although definitive causality remains unconfirmed, the complex interplay between genetic predisposition, immune responses, and viral exposure underscores the need for further mechanistic research. Elucidating these pathways may inform future strategies for targeted prevention, early detection, and vaccine or antiviral development in at-risk populations. Full article

Background: Despite distinct etiologies, type 1 diabetes (T1D) and type 2 diabetes (T2D) share chronic inflammation as a core feature. Interleukins, key immune mediators, play important yet still not fully understood roles in the development and complications of both conditions. Objective: This narrative review aims to provide a comprehensive and critical synthesis of current evidence on the role of key interleukins in T1D and T2D, highlighting their immunological functions, genetic associations, clinical correlations, and translational potential. Methods: A targeted literature search was conducted in PubMed, Google Scholar, and ScienceDirect up to January 2025, focusing on English-language clinical and experimental studies involving interleukins and their relevance to T1D and T2D. Reference lists were manually screened for additional sources. Interleukins (ILs) were reviewed individually to assess their immunobiology, disease specificity, and biomarker or therapeutic value. Findings: Pro-inflammatory cytokines such as IL-1β, IL-6, and IL-17 contribute to islet inflammation, insulin resistance, and microvascular damage in both T1D and T2D. Anti-inflammatory mediators including IL-4, IL-10, and IL-13 exhibit protective effects but vary in expression across disease stages. Less-characterized interleukins such as IL-3, IL-5, IL-9, and IL-27 demonstrate dual or context-dependent roles, particularly in shaping immune tolerance and tissue-specific complications such as nephropathy and neuropathy. Polymorphisms in IL-10 and IL-6 genes further suggest genetic contributions to interleukin dysregulation and metabolic dysfunction. Despite promising insights, translational gaps persist due to overreliance on preclinical models and limited longitudinal clinical data. Conclusions: Interleukins represent a mechanistic bridge linking immune dysregulation to metabolic derangements in both T1D and T2D. While their diagnostic and therapeutic potential is increasingly recognized, future research must address current limitations through isoform-specific targeting, context-aware interventions, and validation in large-scale, human cohorts. A unified interleukin-based framework may ultimately advance personalized strategies for diabetes prevention and treatment. Full article

REG3A, a prominent member of the human regenerating islet-derived (REG) lectin family, plays a pivotal and multifaceted role in immune defense, inflammation, and cancer biology. Primarily expressed in gastrointestinal epithelial cells, REG3A reinforces barrier integrity, orchestrates mucosal immune responses, and regulates host–microbiota interactions. It also functions as a potent non-enzymatic antioxidant, protecting tissues from oxidative stress. REG3A expression is tightly regulated by inflammatory stimuli and is robustly induced during immune activation, where it limits microbial invasion, dampens tissue injury, and promotes epithelial repair. Beyond its antimicrobial and immunomodulatory properties, REG3A contributes to the resolution of inflammation and the maintenance of tissue homeostasis. However, its role in cancer is highly context-dependent. In some tumor types, REG3A fosters malignant progression by enhancing cell survival, proliferation, and invasiveness. In others, it acts as a tumor suppressor, inhibiting growth and metastatic potential. These opposing effects are likely dictated by a combination of factors, including the tissue of origin, the composition and dynamics of the tumor microenvironment, and the stage of disease progression. Additionally, the secreted nature of REG3A implies both local and systemic effects, further modulated by organ-specific physiology. Experimental variability may also reflect differences in methodologies, analytical tools, and model systems used. This review synthesizes current knowledge on the pleiotropic functions of REG3A, emphasizing its roles in epithelial defense, immune regulation, redox homeostasis, and oncogenesis. A deeper understanding of REG3A’s pleiotropic effects could open up new therapeutic avenues in both inflammatory disorders and cancer. Full article

Background/Objectives: Organ transplantation is a life-saving intervention for patients with terminal organ failure, but long-term success is hindered by graft rejection and dependence on lifelong immunosuppressants. These drugs pose risks such as opportunistic infections and malignancies. Chimeric antigen receptor (CAR) technology, originally developed for cancer immunotherapy, has been adapted to regulatory T cells (Tregs) to enhance their antigen-specific immunosuppressive function. This systematic review evaluates the preclinical development of CAR-Tregs in promoting graft tolerance and suppressing graft-versus-host disease (GvHD). Methods: A systematic review following PROSPERO guidelines (CRD420251073207) was conducted across PubMed, Scopus, and Web of Science for studies published from 2015 to 2024. After screening 105 articles, 17 studies involving CAR-Tregs in preclinical or in vivo transplant or GvHD models were included. Results: CAR-Tregs exhibited superior graft-protective properties compared to unmodified or polyclonal Tregs. HLA-A2-specific CAR-Tregs consistently improved graft survival, reduced inflammatory cytokines, and suppressed immune cell infiltration across skin, heart, and pancreatic islet transplant models. The inclusion of CD28 as a co-stimulatory domain enhanced Treg function and FOXP3 expression. However, challenges such as Treg exhaustion, tonic signaling, and reduced in vivo persistence were noted. Some studies reported synergistic effects when CAR-Tregs were combined with immunosuppressants like rapamycin or tacrolimus. Conclusions: CAR-Tregs offer a promising strategy for inducing targeted immunosuppression in allogeneic transplantation. While preclinical findings are encouraging, further work is needed to optimize CAR design, ensure in vivo stability, and establish clinical-scale manufacturing before translation to human trials. Full article

Insulin-degrading enzyme is a zinc metalloprotease that degrades low-molecular-weight substrates, including insulin. Ubiquitous expression, high evolutionary conservation, upregulation of Ide in stress situations, and literature findings suggest a broader function of Ide in cell physiology and protein homeostasis that remains to be elucidated. We used proteomics and transcriptomics approaches to search for leads related to a broader role of Ide in protein homeostasis. We combined an analysis of the proteome and single-cell transcriptome of Ide^+/+ and Ide^−/− pancreatic islet cells with an examination of the interactome of human cytosolic Ide using proximity biotinylation. We observe an upregulation of pathways related to RNA processing, translation and splicing in Ide^+/+ relative to Ide^−/− islet cells. Corroborating these results and providing a potential mechanistic explanation, proximity biotinylation reveals interaction of Ide with several subunits of CCR4-NOT, a key mRNA deadenylase regulating gene expression “from birth to death”. We propose a speculative model in which human and murine Ide cooperate with CCR4-NOT to control protein expression in proteotoxic and metabolic stress situations through cooperation between their deadenylase and protease functions. Full article

A hallmark of type 2 diabetes mellitus (T2DM) is the presence of abundant amyloid deposits composed of amyloid polypeptide (amylin) within the pancreatic islets of Langerhans. Given its high prevalence among diabetic individuals, human amylin fibrillization has long been considered a key pathogenic factor in T2DM. Co-secreted with insulin, amylin can misfold and aggregate, inducing β-cell toxicity, impairing insulin secretion, and accelerating disease progression. Emerging evidence also indicates that amylin accumulates in the brains of patients with Alzheimer’s disease, where it may interact with amyloid-β (Aβ) to promote neurodegeneration. Although the underlying mechanisms remain under investigation, amylin aggregates have been shown to disrupt mitochondrial function, trigger endoplasmic reticulum stress, and activate the NLRP3 inflammasome. Additionally, T2DM-associated cerebrovascular alterations may compound cognitive decline. This review, based on a comprehensive literature search across major biomedical databases up to January 2025, synthesizes current evidence on amylin as a molecular link between metabolic and neurodegenerative disorders. We highlight pancreatic β-cell amylin aggregation as a potential early marker of dementia risk in T2DM and examine its relationship with proteostasis-associated proteins. Finally, we discuss emerging diagnostic and therapeutic strategies targeting amylin pathology, offering new perspectives on preventing or delaying neurodegeneration in individuals with T2DM. Full article

Mitochondria possess a double-membrane envelope which is susceptible to insult by pathogenic intracellular aggregates of amyloid-forming peptides, such as the amyloid-beta (1-42) (Aβ42) peptide and the human islet amyloid polypeptide (hIAPP). The molecular composition of membranes plays a pivotal role in regulating peptide aggregation and cytotoxicity. Therefore, we hypothesized that modifying the physicochemical properties of mitochondrial model membranes with a small molecule might act as a countermeasure against the formation of, and damage by, membrane-active amyloid peptides. To investigate this, we inserted the natural ubiquinone Coenzyme Q10 (CoQ10) in model mito-mimetic lipid vesicles, and studied how they interacted with Aβ42 and hIAPP peptide monomers and oligomers. Our results demonstrate that the membrane incorporation of CoQ10 significantly attenuated fibrillization of the peptides, whilst also making the membranes more resilient against peptide-induced permeabilization. Furthermore, these protective effects were linked with the ability of CoQ10 to enhance membrane packing in the inner acyl chain region, which increased the mechanical stability of the vesicle membranes. Based on our collective observations, we propose that mitochondrial resilience against toxic biomolecules implicit in protein misfolding disorders such as Alzheimer’s disease and type-2 diabetes, could potentially be enhanced by increasing CoQ10 levels within mitochondria. Full article

Ryanodine receptors (RyRs) are large intracellular Ca²⁺ release channels primarily found in muscle and nerve cells and also present at low levels in pancreatic islet endocrine cells. This review examines the role of RyRs in islet cell function, focusing on calcium signaling and hormone secretion, while addressing the ongoing debate regarding their significance due to their limited expression. We explore conflicting experimental results and their potential causes, synthesizing current knowledge on RyR isoforms in islet cells, particularly in beta and delta cells. The review discusses how RyR-mediated calcium-induced calcium release enhances, rather than drives, glucose-stimulated insulin secretion. We examine the phosphorylation-dependent regulation of beta-cell RyRs, the concept of “leaky ryanodine receptors”, and the roles of RyRs in endoplasmic reticulum stress, apoptosis, store-operated calcium entry, and beta-cell electrical activity. The relationship between RyR dysfunction and the development of impaired insulin secretion in diabetes is assessed, noting their limited role in human diabetes pathogenesis given the disease’s polygenic nature. We highlight the established role of RyR-mediated CICR in the mechanism of action of common type 2 diabetes treatments, such as glucagon-like peptide-1, which enhances insulin secretion. By integrating findings from electrophysiological, molecular, and clinical studies, this review provides a balanced perspective on RyRs in islet cell physiology and pathology, emphasizing their significance in both normal insulin secretion and current diabetes therapies. Full article

Background/Objectives: Antibiotics have a significant impact on the gut microbiota, and we hypothesized that human milk oligosaccharides may alleviate antibiotic-induced gut microbiota dysbiosis. Methods: Six groups of eight mice were administered drinking water with or without ampicillin for one week. We then introduced the human milk oligosaccharide 2′-fucosyllactose (2′FL), either alone or in combination with difucosyl-lactose (DFL), for two weeks after the termination of ampicillin treatment. Results: Ampicillin reduced microbiota diversity and the abundance of specific bacteria. One week after the termination of ampicillin treatment, the 2′FL + DFL mixture counteracted the ampicillin-induced reduction in diversity, although this effect was not sustained. Over the subsequent two weeks, the 2′FL + DFL mixture had a significant impact on the relative abundances of Lactobacillus spp. and Bacteroides spp. Ampicillin also reduced caecal propionate levels, downregulated the gene Gzmb for Granzyme B, and upregulated the gene Reg3a for Regenerating islet-derived protein 3 alpha, all of which were counteracted by the 2′FL + DFL mixture. Ampicillin had a minor impact on ileal cytokine levels. The 2′FL + DFL mixture showed a cytokine effect indicating reduced adaptive and innate inflammation. Ampicillin reduced water intake and growth in the mice. The oligosaccharides did not affect water intake, but the 2′FL + DFL mixture slightly reduced body weight. Conclusions: The 2′FL + DFL mixture appears to hold potential for counteracting some of the side effects of ampicillin treatment. Full article

Background/Objectives: Type 2 diabetes mellitus (T2DM) is a major global health challenge, primarily driven by insulin resistance and beta-cell dysfunction. This study investigated the roles of p21-activated kinase 1 (PAK1) and calcium/calmodulin-dependent protein kinase II (CAMKII) in insulin secretion, aiming to elucidate their involvement in this process and their implications in T2DM pathophysiology. Methods: Using the Beta-TC-6 insulinoma cell line, we assessed colocalization and interaction of PAK1 and CAMKII under glucose stimulation through indirect immuno-fluorescence (IFI) and proximity ligation assays (PLA). To examine their expression dynamics in a physiological context, we performed immunohistochemistry (IHC) on pancreatic sections from wild-type (WT), prediabetic, and T2DM murine models. Additionally, bioinformatic analysis of publicly available RNA sequencing (RNA-Seq) data from human islets of healthy donors, prediabetic individuals, and T2DM patients provided translational validation. Results: High glucose conditions significantly increased PAK1-CAMKII colocalization, correlating with enhanced insulin secretion. Pharmacological inhibition of these kinases reduced insulin release, confirming their regulatory roles. Murine and human islet analyses showed a progressive increase in kinase expression from prediabetes to T2DM, highlighting their relevance in disease progression. Conclusions: The coordinated function of PAK1 and CaMKII in insulin secretion suggests their potential as biomarkers and therapeutic targets in T2DM. Further studies are warranted to explore their mechanistic roles and therapeutic applications in preserving beta-cell function. Full article

Inflammation of the exocrine pancreas accompanies autoimmune diabetes in mouse models and humans. However, the relationship between inflammation in the exocrine and endocrine (islet) compartments has not been explored. To address this issue, we used a transgenic mouse model in which autoimmune diabetes is acutely induced after the transfer of islet beta cell-specific transgenic T cells. Histological analyses demonstrated that inflammation of the exocrine pancreas, which was initially mild, resulted in the transient but widespread disruption of acinar tissue. Islet inflammation preceded exacerbated exocrine pathology, progressed to T cell-induced islet damage/destruction and persisted when exocrine inflammation subsided. Heparanase-1 (HPSE-1), an endoglycosidase that degrades heparan sulfate in basement membranes (BMs), when preferentially expressed in recipient cells but not donor (HPSE-1-deficient (HPSE-KO)) T cells, played a critical role in both exocrine and islet inflammation. In this context, HPSE-1 facilitates the passage of autoimmune T cells across the sub-endothelial basement membrane (BM) of pancreatic blood vessels and initially into the exocrine tissue. Peak exocrine inflammation that preceded or accompanied the acute onset of diabetes and HPSE-1 potentially contributed to acinar damage. In contrast to inflammation, HPSE-1 expressed by donor T cells played a key role in the induction of diabetes by allowing autoimmune T cells to traverse peri-islet BMs in order to destroy insulin-producing beta cells. Overall, our findings suggest that major exocrine pancreas injury is not required for the initiation of autoimmune islet damage and is not essential at the time of diabetes onset. Full article

The assembly of amyloidogenic proteins and peptides into toxic oligomeric and fibrillar aggregates is closely connected to the onset and progression of more than 50 protein diseases, such as Alzheimer’s disease, Parkinson’s disease, prion disease, and type 2 diabetes, to name only a few. Considerable research efforts at identifying the therapeutic strategies against these maladies are currently focused on preventing and inhibiting pathogenic protein aggregation by various agents. Plant-based extracts and compounds have emerged as promising sources of potential inhibitors due to their dual role as nutraceuticals as part of healthy diets and as specific pharmaceuticals when administered at higher concentrations. In recent decades, several plant extracts and plant-extracted compounds have shown potential to modulate protein aggregation. An ever-growing body of research on plant-based amyloid inhibitors requires a detail analysis of existing data to identify potential knowledge gaps. This review summarizes the recent progress in amyloid inhibition using 17 flavonoids, 11 polyphenolic non-flavonoid compounds, 23 non-phenolic inhibitors, and 59 plant extracts, with the main emphasis on directly modulating the fibrillation of four amyloid proteins, namely amyloid-β peptide, microtubule-associated protein tau, α-synuclein, and human islet amyloid polypeptide. Full article

Integration of old and recent experimental data consequences is needed to correct and help improve the hypothetical mechanism responsible for the stimulus–secretion coupling mechanism of glucose-induced insulin secretion. The main purpose of this review is to supply biochemical considerations about some of the metabolic pathways implicated in the process of insulin secretion. It is emphasized that glucose β-cells’ threshold to activate secretion (5 mM) might depend on the predominance of anaerobic glycolysis at this basal glucose concentration. This argues against the predominance of phosphoenolpyruvate (PEP) over mitochondrial pyruvate oxidation for the initiation of insulin secretion. Full quantitative and qualitative reproduction, except the threshold effect, of glucose-induced insulin release by a permeable methylated analog of succinic acid indicates that mitochondrial metabolism is enough for sustained insulin secretion. Mitochondrial PEP generation is skipped if the GABA-shunt pathway is exclusively coupled to the citric acid cycle, as proposed in the “GABA-shunt” model of stimulus–secretion coupling. Strong or maintained depolarization by KCl or sulfonylureas might induce the opening of β-cells Cx36 hemichannels, allowing the loss of adenine nucleotides and other metabolites, mimicking the effect of an excessive mitochondrial ATP demand. A few alterations of OxPhos (Oxidative Phosphorylation) regulation in human T2D islets have been described, but the responsible mechanism(s) is (are) not yet known. Finally, some experimental data arguing as proof of the relative irrelevance of the mitochondrial function in the insulin secretion coupling mechanism for the initiation and/or sustained stimulation of hormone release are discussed. Full article