The Role of Oxidative Stress in Pancreatic β Cell Dysfunction in Diabetes

Atf4 Protects Islet β-Cell Identity and Function Under Acute Glucose-Induced Stress but Promotes β-Cell Failure in the Presence of Free Fatty Acid

Glucolipotoxicity, caused by combined hyperglycemia and hyperlipidemia, results in β-cell failure and type 2 diabetes via cellular stress-related mechanisms. Activating transcription factor 4 (Atf4) is an essential effector of stress response. We show here that Atf4 expression in β-cells is minimally required for glucose homeostasis in juvenile and adolescent mice but it is needed for β-cell function during aging and under obesity-related metabolic stress. Henceforth, Atf4-deficient β-cells older than 2 months after birth display compromised secretory function under acute hyperglycemia. In contrast, they are resistant to acute free fatty acid-induced dysfunction and reduced production of several factors essential for β-cell identity. Atf4-deficient β-cells downregulate genes involved in protein translation. They also upregulate several lipid metabolism or signaling genes, likely contributing to their resistance to free fatty acid-induced dysfunction. These results suggest that Atf4 activation is required for β-cell identity and function under high glucose. But Atf4 activation paradoxically induces β-cell failure in high levels of free fatty acids. Different transcriptional targets of Atf4 could be manipulated to protect β-cells from metabolic stress-induced failure.

ARTICLE HIGHLIGHTS

Pancreatic β-cell apoptosis caused by apolipoprotein C3-rich low-density lipoprotein is attenuated by kansuinine A through oxidative stress inhibition

Dyslipidemia exacerbates pancreatic β-cell apoptosis, heightening the risk of type 2 diabetes (T2DM). Kansuinine A (KA), a diterpene from Euphorbia roots, exhibits antiapoptotic properties, suggestive of its therapeutic potential against T2DM. In this study, we evaluated the protective effects of KA against apolipoprotein C3 (ApoC3)-rich low-density lipoprotein (LDL) (AC3RL)-induced β-cell apoptosis and its underlying mechanism of action. ApoE-/- mice fed a high-fat diet and treated with KA demonstrated improved glucose and insulin tolerance, enhanced antioxidant capacity, and reduced pancreatic β-cell apoptosis. In rat pancreatic β-cells (RIN-m5F) exposed to AC3RL, KA significantly improved cell viability, suppressed oxidative stress, and mitigated apoptosis by downregulating lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) expression and inhibiting the IκB kinase β (IKKβ)/Inhibitor of κB alpha (IκB⍺)/Nuclear Factor kappa B(NF-κB) signaling pathway. Molecular docking and pathway analyses revealed the interactions of KA with key targets involved in oxidative stress and apoptosis. These findings highlight the ability of KA to counteract AC3RL-induced β-cell dysfunction, offering promise as a potential intervention for dyslipidemia-driven diabetes.

Malvidin-3-glucoside induces insulin secretion by activating the PLC/IP3 pathway and enhancing Ca2+ influx in INS-1 pancreatic β-cells

Malvidin-3-glucoside (M3G), an anthocyanin found in blueberries and grapes, shows promise as a natural anti-diabetic agent. However, its effect on insulin secretion and its underlying mechanisms remains unclear. This study investigated the impact of M3G on β-cells (INS-1) through real-time Ca2+ imaging and insulin secretion assays. M3G increased intracellular Ca2+ levels in a concentration-dependent manner, specifically targeting β-cells without affecting other pancreatic cell types. It enhanced insulin secretion under both basal (4 mM) and stimulatory (11 mM) glucose conditions while maintaining cell viability at concentrations up to 100 µM. Pharmacological inhibitors revealed that M3G-induced Ca2+ signals resulted from both Ca influx through L-type voltage-dependent calcium channels (L-type VDCCs) and Ca2+ release from the endoplasmic reticulum (ER) via the PLC/IP3 pathway. Nimodipine, an L-type VDCC blocker, inhibited M3G-induced Ca2+ influx, while U73122 (a PLC inhibitor) and 2-aminoethoxydiphenyl borate (2-APB), an IP3 receptor blocker, suppressed Ca2+ release from the ER. Additionally, M3G upregulated the expression of key glucose-stimulated insulin secretion (GSIS)-related genes, including Ins1 (insulin), Slc2a2 (GLUT2), and Gck (glucokinase). These findings suggest that M3G stimulates insulin secretion by promoting Ca2+ influx through L-type VDCCs, facilitating Ca2+ release from the ER, and upregulating GSIS-related genes. M3G holds promise as a natural anti-diabetic agent by enhancing insulin secretion and supporting β-cell function.

Activatable Photosensitizers: From Fundamental Principles to Advanced Designs

Photodynamic therapy (PDT) is a promising treatment that uses light to excite photosensitizers in target tissue, producing reactive oxygen species and localized cell death. It is recognized as a minimally invasive, clinically approved cancer therapy with additional preclinical applications in arthritis, atherosclerosis, and infection control. A hallmark of ideal PDT is delivering disease-specific cytotoxicity while sparing healthy tissue. However, conventional photosensitizers often suffer from non-specific photoactivation, causing off-target toxicity. Activatable photosensitizers (aPS) have emerged as more precise alternatives, offering controlled activation. Unlike traditional photosensitizers, they remain inert and photoinactive during circulation and off-target accumulation, minimizing collateral damage. These photosensitizers are designed to "turn on" in response to disease-specific biostimuli, enhancing therapeutic selectivity and reducing off-target effects. This review explores the principles of aPS, including quenching mechanisms stemming from activatable fluorescent probes and applied to activatable photosensitizers (RET, PeT, ICT, ACQ, AIE), as well as pathological biostimuli (pH, enzymes, redox conditions, cellular internalization), and bioresponsive constructs enabling quenching and activation. We also provide a critical assessment of unresolved challenges in aPS development, including limitations in targeting precision, selectivity under real-world conditions, and potential solutions to persistent issues (dual-lock, targeting moieties, biorthogonal chemistry and artificial receptors). Additionally, it provides an in-depth discussion of essential research design considerations needed to develop translationally relevant aPS with improved therapeutic outcomes and specificity.

Evaluating the Molecular Interactions between Type 2 Diabetes Mellitus and Parkinson's Disease: Role of Antidiabetic Drugs as Promising Therapeutics

Evidence from previous research demonstrates a relationship between diabetes mellitus (DM) and Parkinson's disease (PD). T2DM is associated with chronic glucose dysregulation, as an etiological factor. It inhibits neuronal function through disrupted insulin signaling and oxidative stress, which ultimately lead to the loss of dopaminergic neurons in the substantia nigra (SN). Interactions between T2DM and PD were analyzed by gene expression, coexpression, and gene set enrichment via NCBI and STRING databases following pathways like KEGG and Reactome. The study identified nine key gene interactions through published literature on different databases and search engines that are involved in the progression of these chronic diseases. Furthermore, some genetic and nongenetic risk factors, gene mutations and environmental factors, are also involved in the progression of T2DM and PD. This review highlights the limitations of currently available drug treatments for these diseases and examines modern therapeutic approaches to address neurodegenerative and metabolic abnormalities. We critically assess the current experimental methodologies aimed at unraveling the pathophysiological mechanisms linking PD and T2DM while addressing the key challenges impeding a comprehensive understanding of the concurrent emergence of these debilitating age-related conditions.

Short-term exposure to PM2.5 and its components and type 2 diabetes-related hospital admissions, length of stay, and hospital costs in Shanghai

The short-term influence of particles with an aerodynamic diameter ≤2.5 μm (PM2.5) and its individual elements on hospital costs, the length of hospital stay (LOS), and hospital admissions caused by type 2 diabetes remains unclear. A generalized additive model (GAM) with quasi-Poisson distribution was utilized to assess the association of individual pollutants and mixtures. For every 10 μg/m3 rise in PM2.5 and a per-SD increase in NH4+at lag0, hospital admissions increased by 0.93% (95% CI: 0.68, 1.19) and 2.81% (95% CI: 2.20, 3.42); hospital costs rose by 24.58 thousands of CNY (95% CI: 5.95, 43.22) and 77.06 thousands of CNY (95% CI: 33.07, 121.04); LOS increased by 9.53 days (95% CI: 0.44, 18.62) and 27.80 days (95% CI: 6.34, 49.27), respectively. Factor analysis showed that mixed-source particulate pollution was significantly associated with an increase in hospital admissions (0.27%, 95% CI: (0.20, 0.34)), LOS (2.87 days, 95% CI: (0.35, 5.40)), and hospital costs (71.68 thousands of CNY, 95% CI: (19.89,123.46)). These findings suggested that short-term exposure to elevated levels of PM2.5 as well as its components increased the risk of hospital costs, LOS, and hospital admissions due to type 2 diabetes.

Non-linear relationship between triglyceride glucose index and new-onset diabetes among individuals with non-alcoholic fatty liver disease: a cohort study

BACKGROUND

The relationship between the triglyceride glucose (TyG) values and the development of diabetes in non-alcoholic fatty liver disease (NAFLD) patients is not yet well researched. This study aims to examine how the baseline TyG levels correlate with the incidence of new-onset diabetes in this specific cohort.

METHODS

This cohort included 2,506 normoglycemic Japanese adults with NAFLD who underwent routine health check-ups at Murakami Memorial Hospital between 2004 and 2015. Several statistical approaches, including restricted cubic splines and two-piecewise linear regression, were utilized to assess the relation between the TyG levels and diabetes risk.

RESULTS

Among the 2,506 participants (mean age: 44.78 ± 8.32 years; 81.09% male), 203 individuals (8.10%) developed diabetes over the course of the 11-year follow-up period. A U-shaped relationship was observed between the levels of TyG and the onset of diabetes, with an inflection point identified at a TyG value of 7.82 (95% CI: 7.72-8.00). Below this threshold, each one-unit elevation in TyG values reduced the probability of diabetes by 93% (HR = 0.07, 95% CI: 0.01-0.32, P = 0.001). Conversely, above this threshold, each one-unit elevation increased the probability of diabetes by 70% (HR = 1.70, 95% CI: 1.19-2.44, P = 0.004).

CONCLUSIONS

The findings validate a U-shaped association between TyG levels and new-onset diabetes in adults with NAFLD. Both low and high TyG levels increase diabetes probability in such a group.

Antioxidant Supplementation for Management of Gestational Diabetes Mellitus in Pregnancy: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

PURPOSE OF REVIEW

Gestational diabetes mellitus (GDM) is the most common medical complication of pregnancy globally. Hyperglycaemia and associated production of reactive oxygen species can lead to oxidative stress in pregnancy. However, the potential effectiveness of increased antioxidant intake in the management of GDM has not been widely examined. Its usefulness alongside medical nutrition therapy (MNT) for assisting glycaemic control in women with GDM is poorly understood. This review aimed to establish the effect of antioxidant supplementation on the risk and management of gestational diabetes mellitus (GDM).

RECENT FINDINGS

A systematic review of intervention studies was conducted based on PRISMA guidelines. Databases searched were MEDLINE, CINAHL, Global Health, Scopus, Embase and Cochrane until September 2024. Random effects meta-analyses using Cochrane Review Manager software to establish the effect of antioxidant supplementation on glucose outcomes in women with GDM were conducted. A total of 13 studies (1380 participants) were included in the review with four different antioxidants used (selenium (n = 3); alpha-lipoic (n = 4); zinc (n = 5); e-3-gallate (n = 1)). Significant pre-post differences between antioxidant supplementation and control groups were found for fasting insulin (SMD, 95%CI) (-0.97 [-1.69 -0.24]; p = 0.009, HOMA-IR (-0.90 [-1.25, -0.54]; p < 0.0000, HOMA-B (-0.86 [-1.05, -0.67]; p < 0.00001 and QUICKI (1.09 [0.32,1.87]; p = 0.005 Heterogeneity was substantial (I2 > 50%, p < 0.05) for all models except for HOMA-B (I2 = 0%, p > 0.05). Antioxidant supplementation has possible benefit as an adjunct therapy to current dietary management for women with GDM. Further clinical trials are needed to establish the preferred type and dosage of antioxidants likely to be effective.

Advancements in Injectable Hydrogels for Controlled Insulin Delivery: A Comprehensive Review of the Design, Properties and Therapeutic Applications for Diabetes and Its Complications

Glycemic management in diabetes patients remains heavily reliant on multiple daily insulin injections, which often leads to poor patient compliance and an elevated risk of hypoglycemia. To overcome these limitations, injectable hydrogels capable of encapsulating insulin within polymeric networks have emerged as a promising alternative. Ideally, a single injection can form an in situ depot that allows prolonged glycemic control and lower injection frequency. This review summarizes recent advances in injectable hydrogels for controlled insulin delivery, focusing on the polymer sources, crosslinking strategies, and stimuli-responsive release mechanisms. Synthetic polymers such as PEG, PNIPAM, and Pluronics dominate the current research due to their highly tunable properties, whereas naturally derived polysaccharides and proteins generally require further modifications for enhanced functionality. The crosslinking types, ranging from relatively weak physical interactions (hydrogen bonds, hydrophobic interactions, etc.) to dynamic covalent bonds with higher binding strength (e.g., Schiff base, phenylboronate ester), significantly influence the shear-thinning behavior and stimuli-responsiveness of hydrogel systems. Hydrogels' responsiveness to temperature, glucose, pH, and reactive oxygen species has enabled more precise insulin release, offering new options for improved diabetic management. Beyond glycemic regulation, this review also explores insulin-loaded hydrogels for treating complications. Despite the progress, challenges such as burst release, long-term biocompatibility, and scalability remain. Future research should focus on optimizing hydrogel design, supported by robust and comprehensive data.

Metabolic interventions as adjunctive therapies to insulin in type 1 diabetes: Current clinical landscape and perspectives

Type 1 diabetes (T1D) is classically characterized as an autoimmune disease wherein the immune system erroneously attacks insulin-producing pancreatic β-cells, causing insulin insufficiency and severe metabolic dysregulation. However, intensive investigation and numerous clinical trials with immunotherapies have been largely unable to significantly alter the course of disease. Currently, there is no effective way to prevent or cure T1D, and insulin remains the cornerstone of T1D treatment. In recent years, a growing body of research suggests that β-cells actively contribute to the immune response and to disease development. Factors including glucotoxicity, lipotoxicity, inflammation, endoplasmic reticulum (ER) and oxidative stress can induce β-cell apoptosis and senescence, further promoting insulitis. Recent studies highlight the importance of targeting metabolic control for T1D management and treatment. Metabolic interventions, through their direct and indirect impacts on β-cells, have shown promise in preserving β-cell function. These interventions can reduce glucose toxicity, alleviate oxidative stress and inflammation, enhance insulin sensitivity, and indirectly mitigate the autoimmune responses. By preserving β-cell function, individuals with T1D attain better glycaemic control, reduced complication risks and exhibit improved overall metabolic health. Here, we provide an overview of insights from clinical studies, systematic reviews and meta-analyses that collectively demonstrate that adjunctive metabolic interventions can enhance glycaemic control, reduce insulin requirements and mitigate adverse effects associated with insulin monotherapy. They also show potential for halting disease progression, preserving residual β-cell function and improving long-term outcomes for newly diagnosed individuals. Future research should focus on optimizing these treatment strategies and establishing their long-term efficacy and safety.

The herbicide 2,4-dichlorophenoxyacetic acid induces pancreatic β-cell death via oxidative stress-activated AMPKα signal downstream-regulated apoptotic pathway

2,4-Dichlorophenoxyacetic acid (2,4-D) is one of commonly and widely used organic herbicides in agriculture. It has been reported that 2,4-D can induce adverse effects in mammalian cells. Epidemiological and animal studies have indicated that exposure to 2,4-D is associated with poorer glycemic control and impaired pancreatic β-cell function. However, limited information is available on 2,4-D-induced toxicological effects in β-cells, with the underlying toxicological mechanisms remains unclear. Herein, our results showed that 2,4-D exposure (30-500 μg/mL) significantly reduced cell viability, induced mitochondria dysfunction (including the mitochondrial membrane potential (MMP) loss, the increase in cytosolic cytochrome c release, and the change in Bcl-2 and Bax protein expression), and triggered apoptotic events (including the increased population of apoptotic cells, caspase-3 activity, and caspase-3/-7 and PAPR activation) in RIN-m5F β-cells, accompanied with insulin secretion inhibition. Exposure of cells to 2,4-D could also evoke JNK, ERK1/2, p38, and AMP-activated protein kinase (AMPK)α activation as well as reactive oxygen species (ROS) generation. Pretreatment of cells with compound C (an AMPK inhibitor) and the antioxidantN-acetylcysteine (NAC), but not that SP600125/PD98059/SB203580 (the inhibitors of JNK/ERK/p38, respectively), obviously attenuated the 2,4-D-triggered AMPKα phosphorylation, MMP loss, apoptotic events, and insulin secretion dysfunction,as similar effects with the transfection with AMPKα1-specific siRNA. Of note, buffering the ROS production with NAC obviously prevented the 2,4-D-induced ROS generation as well as AMPKα activation, but the either compound C and AMPKα1-specific siRNA transfection could not effectively reduce 2,4-D-induced ROS generation. Collectively, these findings indicate that the induction of oxidative stress-activated AMPKα signaling is a crucial mechanism underlying 2,4-D-triggered mitochondria-dependent apoptosis, ultimately leading to β-cell death.

Myelin transcription factors 1 and 3 have overlapping but distinct roles in insulin secretion and survival of human β cells

Islet β-cell dysfunction, loss of identity, and death, together known as β-cell failure, lead to reduced inulin output and Type 2 diabetes (T2D). Understanding how β-cells avoid this failure holds the key to preventing or delaying the development of this disease. Here, we examine the roles of two members of the Myelin transcription factor family (including MYT1, 2, and 3) in human β-cells. We have reported that these factors together prevent β-cell failure by repressing the overactivation of stress response genes in mice and human β-cell lines. Single-nucleotide polymorphisms in MYT2 and MYT3 are associated with human T2D. These findings led us to examine the roles of these factors individually in primary human β-cells. By knocking down MYT1 or MYT3 separately in primary human donor islets, we show here that these TFs have distinct functions. Under normal physiological conditions, high MYT1 expression is required for β-cell survival, while high MYT3 expression is needed for glucose-stimulated insulin secretion. Under obesity-induced metabolic stress, MYT3 is also necessary for β-cell survival. Accordingly, these TFs regulate different genes, with MYT1-KD de-regulating several in protein translation and Ca2+ binding, while MYT3-KD de-regulating genes involved in mitochondria, ER, etc. These findings highlight not only the family member-specific functions of each TF but also the multilayered protective function of these factors in human β-cell survival under different levels of metabolic stress.

Chronic intermittent fasting impairs β cell maturation and function in adolescent mice

Intermittent fasting (IF) is a nutritional lifestyle intervention with broad metabolic benefits, but whether the impact of IF depends on the individual's age is unclear. Here, we investigated the effects of IF on systemic metabolism and β cell function in old, middle-aged, and young mice. Short-term IF improves glucose homeostasis across all age groups without altering islet function and morphology. In contrast, while chronic IF is beneficial for adult mice, it results in impaired β cell function in the young. Using single-cell RNA sequencing (scRNA-seq), we delineate that the β cell maturation and function scores are reduced in young mice. In human islets, a similar pattern is observed in type 1 (T1D), but not type 2 (T2D), diabetes, suggesting that the impact of chronic IF in adolescence is linked to the development of β cell dysfunction. Our study suggests considering the duration of IF in younger persons, as it may worsen rather than reduce diabetes outcomes.

The Role of Reductive Stress in the Pathogenesis of Endocrine-Related Metabolic Diseases and Cancer

Reductive stress (RS), characterized by excessive accumulation of reducing equivalents such as NADH and NADPH, is emerging as a key factor in metabolic disorders and cancer. While oxidative stress (OS) has been widely studied, RS and its complex interplay with endocrine regulation remain less understood. This review explores molecular circuits of bidirectional crosstalk between metabolic hormones and RS, focusing on their role in diabetes, obesity, cardiovascular diseases, and cancer. RS disrupts insulin secretion and signaling, exacerbates metabolic inflammation, and contributes to adipose tissue dysfunction, ultimately promoting insulin resistance. In cardiovascular diseases, RS alters vascular smooth muscle cell function and myocardial metabolism, influencing ischemia-reperfusion injury outcomes. In cancer, RS plays a dual role: it enhances tumor survival by buffering OS and promoting metabolic reprogramming, yet excessive RS can trigger proteotoxicity and mitochondrial dysfunction, leading to apoptosis. Recent studies have identified RS-targeting strategies, including redox-modulating therapies, nanomedicine, and drug repurposing, offering potential for novel treatments. However, challenges remain, particularly in distinguishing physiological RS from pathological conditions and in overcoming therapy-induced resistance. Future research should focus on developing selective RS biomarkers, optimizing therapeutic interventions, and exploring the role of RS in immune and endocrine regulation.

Secretome Analysis of Human and Rat Pancreatic Islets Co-Cultured with Adipose-Derived Stromal Cells Reveals a Signature with Enhanced Regenerative Capacities

Pancreatic islet transplantation (PIT) is a promising treatment for type 1 diabetes (T1D) but faces challenges pre- and post-transplantation. Co-transplantation with mesenchymal stromal cells (MSCs), known for their regenerative properties, has shown potential in improving PIT outcomes. This study examined the secretome of islets cultured alone compared to the secretomes of islets co-cultured with adipose-derived stromal cells (ASCs), a subtype of MSCs, under transplantation-relevant stressors: normoxia, cytokines, high glucose, hypoxia, and combined hypoxia and high glucose. Islet co-culture with ASCs significantly altered the proteome, affecting pathways related to energy metabolism, angiogenesis, extracellular matrix organization, and immune modulation. Key signaling molecules (e.g., VEGF, PDGF, bFGF, Collagen I alpha 1, IL-1α, and IL-10) were differentially regulated depending on culture conditions and ASC presence. Functional assays demonstrated that the co-culture secretome could enhance angiogenesis, collagen deposition, and immune modulation, depending on the stress conditions. These findings highlight possible mechanisms through which ASCs may support islet survival and function, offering insights into overcoming PIT challenges. Moreover, this work contributes to identifying biomarkers of the post-transplantation microenvironment, advancing therapeutic strategies for T1D and regenerative medicine.

The role of oxidative post-translational modifications in type 1 diabetes pathogenesis

The pathogenesis of type 1 diabetes (T1D) involves a complex interplay of genetic predisposition, immune processes, and environmental factors, leading to the selective destruction of pancreatic beta-cells by the immune system. Emerging evidence suggests that intrinsic beta-cell factors, including oxidative stress and post-translational modifications (PTM) of beta-cell antigens, may also contribute to their immunogenicity, shedding new light on the multifaceted pathogenesis of T1D. Over the past 30 years, neoepitopes generated by PTMs have been hypothesized to play a role in T1D pathogenesis, but their involvement has only been systematically investigated in recent years. In this review, we explored the interplay between oxidative PTMs, neoepitopes, and T1D, highlighting oxidative stress as a pivotal factor in immune system dysfunction, beta-cell vulnerability, and disease onset.

Knockoff procedure improves causal gene identifications in conditional transcriptome-wide association studies

Transcriptome-wide association studies (TWASs) have been developed to nominate candidate genes associated with complex traits by integrating genome-wide association studies (GWASs) with expression quantitative trait loci (eQTL) data. However, most existing TWAS methods evaluate the marginal association between a single gene and the trait of interest without accounting for other genes within the same genomic region or the same gene from different tissues. Additionally, false-positive gene-trait pairs can arise due to correlations with the direct effects of genetic variants. In this study, we introduce TWASKnockoff, a new knockoff-based framework for detecting causal gene-tissue pairs using GWAS summary statistics and eQTL data. Unlike marginal testing in traditional TWAS methods, TWASKnockoff examines the conditional independence for each gene-trait pair, considering both correlations in cis-predicted expression across genes and correlations between gene expression levels and genetic variants. TWASKnockoff estimates the theoretical correlation matrix for all genetic elements (cis-predicted expression across genes and genotypes for genetic variants) by averaging estimations from parametric boot-strap samples and then performs knockoff-based inference to detect causal gene-trait pairs while controlling the false discovery rate (FDR). Through empirical simulations and an application to type 2 diabetes (T2D) data, we demonstrate that TWASKnockoff achieves superior FDR control and improves the average power in detecting causal gene-trait pairs at a fixed FDR level.

Association of oxidative balance score with metabolic syndrome and its components in middle-aged and older individuals in the United States

Background

The prevalence of metabolic syndrome (MetS) among middle-aged and older individuals in the U.S. is rising, posing significant mortality risks. Diet is a key factor in MetS development, yet few studies have examined the combined effects of dietary and lifestyle factors on MetS in this group. Recently, the oxidative balance score (OBS), an indicator of oxidative status encompassing diet and physical activity, has attracted interest. This study explores the association between OBS and MetS, as well as its individual components, in middle-aged and older Americans.

Methods

Data from 6,157 participants aged 45 years and older in the National Health and Nutrition Examination Survey (NHANES) (1999-2018) were analyzed. The OBS was calculated using 16 dietary and four lifestyle factors. Logistic regression was used to assess associations between OBS and MetS. Separate analyses examined dietary OBS (DOBS) and lifestyle OBS (LOBS) in relation to MetS.

Results

Higher OBS quartiles were associated with a reduced MetS risk (OR 0.25; 95% confidence interval [CI]: 0.12-0.51; p < 0.0001), after adjusting for confounders. Increased OBS was linked to decreases in waist circumference (WC) (OR 0.41; 95% CI: 0.30-0.51; p < 0.0001), triglycerides (TG) (OR 0.71; 95% CI: 0.53-0.92; p = 0.0139), blood pressure (BP) (OR 0.53; 95% CI: 0.40-0.69; p < 0.0001), and fasting glucose (FG) (OR 0.61; 95% CI: 0.45-0.81; p < 0.0001), while HDL-C increased (OR 0.68; 95% CI: 0.51-0.90; p = 0.0065). DOBS was inversely associated with MetS through reductions in BP and FG and increased HDL-C, though it showed no significant effect on WC or TG. LOBS was associated with reductions across WC, BP, FG, TG, and an increase in HDL-C.

Conclusion

OBS is inversely associated with MetS in middle-aged and older U.S. adults. Enhancing OBS through dietary guidelines emphasizing antioxidant-rich foods, fiber, and unsaturated fats, alongside lifestyle changes like regular exercise, smoking cessation, and moderate alcohol intake, may be crucial in MetS prevention for this population.

Diabetes Associated With Maternally Inherited Diabetes and Deafness (MIDD): From Pathogenic Variant to Phenotype

ARTICLE HIGHLIGHTS

Maternally inherited diabetes and deafness (MIDD) is a mitochondrial disorder characterized primarily by hearing impairment and diabetes. m.3243A>G, the most common phenotypic variant, causes a complex rewiring of the cell with discontinuous remodeling of both mitochondrial and nuclear genome expressions. We propose that MIDD depends on a combination of insulin resistance and impaired β-cell function that occurs in the presence of high skeletal muscle heteroplasmy (approximately ≥60%) and more moderate cell heteroplasmy (∼25%-72%) for m.3243A>G. Understanding the complex mechanisms of MIDD is necessary to develop disease-specific management guidelines that are presently lacking.

The role of glucose-6-phosphatase activity in glucose homeostasis and its potential for diabetes therapy

Glucose-6-phosphatase catalytic subunit (G6PC)1 and G6PC2 are crucial for glucose metabolism, regulating processes like glycolysis, gluconeogenesis, and glycogenolysis. Despite their structural and functional similarities, G6PC1 and G6PC2 exhibit distinct tissue-specific expression patterns, G6P hydrolysis kinetics, and physiological functions. This review provides a comprehensive overview of their enzymology and distinct roles in glucose homeostasis. We examine how inactivating mutations in G6PC1 lead to glycogen storage disease, and how elevated G6PC1 and G6PC2 expression can affect the incidence of diabetic complications, risk for type 2 diabetes mellitus (T2DM) and various cancers. We also discuss the potential of inhibiting G6PC1 and G6PC2 to protect against complications from elevated blood glucose levels, and highlight drug development efforts targeting G6PC1 and G6PC2, and the therapeutic potential of inhibitors for disease prevention.

Mechanistic Studies on the Antidiabetic Properties of Gallotannins

The escalating prevalence of type 2 diabetes (T2DM) has emerged as a global public health dilemma. This ailment is associated with insulin resistance and heightened blood glucose concentrations. Despite the rapid advancements in modern medicine, where a regimen of medications is employed to manage blood glucose effectively, certain treatments manifest significant adverse reactions. Recent studies have elucidated the pivotal role of gallotannins in mitigating inflammation and obesity, potentially reducing the prevalence of obesity-linked T2DM. Gallotannins, defined by their glycosidic cores and galloyl groups, are ubiquitously present in plants, playing diverse biological functions and constituting a significant segment of water-soluble polyphenolic compounds within the heterogeneous tannins group. The structural attributes of gallotannins are instrumental in dictating their myriad biological activities. Owing to their abundance of hydroxyl groups (-OH) and complex macromolecular structure, gallotannins exhibit an array of pro-physiological properties, including antioxidant, anti-inflammatory, antidiabetic, protein-precipitating, and antibacterial effects. Extensive research demonstrates that gallotannins specifically obstruct α-amylase and pancreatic lipase, enhance insulin sensitivity, modulate short-chain fatty acid production, alleviate oxidative stress, exhibit anti-inflammatory properties, and influence the gut microbiota, collectively contributing to their antidiabetic efficacy. This review aims to consolidate and scrutinize the extant literature on gallotannins to furnish essential insights for their potential application in diabetes management.

Molecular Mechanisms Underlying the Therapeutic Potential of Plant-Based α-Amylase Inhibitors for Hyperglycemic Control in Diabetes

BACKGROUND

Diabetes mellitus (DM), arising from pancreatic β-cell dysfunction and disrupted alpha-amylase secretion, manifests as hyperglycemia. Synthetic inhibitors of alphaamylase like acarbose manage glucose but pose adverse effects, prompting interest in plantderived alternatives rich in antioxidants and anti-inflammatory properties.

OBJECTIVE

The current review investigates plant-based alpha-amylase inhibitors, exploring their potential therapeutic roles in managing DM. Focusing on their ability to modulate postprandial hyperglycemia by regulating alpha-amylase secretion, it assesses their efficacy, health benefits, and implications for diabetes treatment.

METHODS

This review examines plant-derived alpha-amylase inhibitors as prospective diabetic mellitus treatments using PubMed, Google Scholar, and Scopus data.

RESULTS

Plant-derived inhibitors, including A. deliciosa, B. egyptiaca, and N. nucifera, exhibit anti-inflammatory and antioxidant properties, effectively reducing alpha-amylase levels in diabetic conditions. Such alpha-amylase inhibitors showed promising alternative treatment in managing diabetes with reduced adverse effects.

CONCLUSION

The current literature concludes that plant-derived alpha-amylase inhibitors present viable therapeutic avenues for diabetes management by modulating alpha-amylase secretion by regulating inflammatory, oxidative stress, and apoptotic mechanisms involved in the pathogenesis of diabetes. Further investigation into their formulations and clinical efficacy may reveal their more comprehensive diabetes therapeutic significance, emphasizing their potential impact on glucose regulation and overall health.

1-Deoxynojirimycin affects high glucose-induced pancreatic beta-cell dysfunction through regulating CEBPA expression and AMPK pathway

This study aims to explore the role of 1-deoxynojirimycin (DNJ) in high glucose-induced β-cells and to further explore the molecular mechanism of DNJ effect on β-cells through network pharmacology. In the study, high glucose treatment of mouse INS-1 cells inhibited cell proliferation and insulin secretion, decreased the expression of Bcl-2 protein and Ins1 and Ins2 genes, promoted apoptosis, and increased cleaved caspase-3 and cleaved caspase-9 expression levels as well as intracellular reactive oxygen species production. DNJ treatment significantly restored the dysfunction of INS-1 cells induced by high glucose, and DNJ showed no toxicity to normal INS-1 cells. Silencing CEBPA promoted, while overexpression of CEBPA relieved the dysfunction of pancreatic β-cells induced by high glucose. DNJ treatment partially restored the pancreatic β-cell dysfunction caused by silencing CEBPA. In conclusion, DNJ can inhibit high glucose-induced pancreatic β-cell dysfunction by promoting the expression of CEBPA.

Nickel Sulfate-Induced GSIS Injury in MIN6 Cells by Activating the JNK Pathway Through Oxidative Stress

Nickel has an impact on human health, especially in the context of the new energy industries. Nickel's influence on glycemia remains controversial, and the effects and mechanisms of nickel on islet function still need further exploration. MIN6 cells were treated with different concentrations of nickel sulfate (NiSO4) (0, 75, 150, and 300 µg/mL) for different durations (0, 12, 24, and 48 h). The study measured cell cycle progression, apoptosis, reactive oxygen species (ROS) production, oxidative stress-related indexes (T-SOD, TBARS, 8-OHdG, and GSH), glucose-induced insulin secretion (GSIS), and the expression of JNK pathway-related proteins, pancreaticoduodenal homeobox-1 (PDX-1), glucose transporter 2 (GLUT2), and forkhead box protein O1 (FOXO1). NiSO4 damaged MIN6 cells in a time- and dose-dependent manner. NiSO4 blocked the cell cycle, induced apoptosis, and reduced insulin secretion in the GSIS experiment. NiSO4 also induced ROS production, increased oxidative stress-related indexes (TRABS and 8-OHdG), and decreased antioxidant stress-related indexes (GSH and T-SOD). In addition, NiSO4 activated the JNK pathway, upregulated FOXO1 protein expression, and inhibited PDX-1 and GLUT2 protein expression, affecting insulin release during GSIS. NiSO4 inhibited the proliferation of MIN6 cells through oxidative stress, aggravated apoptosis, caused functional impairment, upregulated the expression of FOXO1 by activating the JNK pathway, inhibited the expression of PDX-1 and GLUT2 proteins, and impaired the GSIS function of islets.

Chocolate intake and risk of type 2 diabetes: prospective cohort studies

OBJECTIVE

To prospectively investigate the associations between dark, milk, and total chocolate consumption and risk of type 2 diabetes (T2D) in three US cohorts.

DESIGN

Prospective cohort studies.

SETTING

Nurses' Health Study (NHS; 1986-2018), Nurses' Health Study II (NHSII; 1991-2021), and Health Professionals Follow-Up Study (HPFS; 1986-2020).

PARTICIPANTS

At study baseline for total chocolate analyses (1986 for NHS and HPFS; 1991 for NHSII), 192 208 participants without T2D, cardiovascular disease, or cancer were included. 111 654 participants were included in the analysis for risk of T2D by intake of chocolate subtypes, assessed from 2006 in NHS and HPFS and from 2007 in NHSII.

MAIN OUTCOME MEASURE

Self-reported incident T2D, with patients identified by follow-up questionnaires and confirmed through a validated supplementary questionnaire. Cox proportional hazards regression was used to estimate hazard ratios and 95% confidence intervals (CIs) for T2D according to chocolate consumption.

RESULTS

In the primary analyses for total chocolate, 18 862 people with incident T2D were identified during 4 829 175 person years of follow-up. After adjusting for personal, lifestyle, and dietary risk factors, participants consuming ≥5 servings/week of any chocolate showed a significant 10% (95% CI 2% to 17%; P trend=0.07) lower rate of T2D compared with those who never or rarely consumed chocolate. In analyses by chocolate subtypes, 4771 people with incident T2D were identified. Participants who consumed ≥5 servings/week of dark chocolate showed a significant 21% (5% to 34%; P trend=0.006) lower risk of T2D. No significant associations were found for milk chocolate intake. Spline regression showed a linear dose-response association between dark chocolate intake and risk of T2D (P for linearity=0.003), with a significant risk reduction of 3% (1% to 5%) observed for each serving/week of dark chocolate consumption. Intake of milk, but not dark, chocolate was positively associated with weight gain.

CONCLUSIONS

Increased consumption of dark, but not milk, chocolate was associated with lower risk of T2D. Increased consumption of milk, but not dark, chocolate was associated with long term weight gain. Further randomized controlled trials are needed to replicate these findings and further explore the mechanisms.

Diabetes and the associated complications: The role of antioxidants in diabetes therapy and care

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by high blood sugar levels (hyperglycemia). Poorly managed diabetes can lead to complications affecting multiple organ systems. Antioxidants play a crucial role in reducing oxidative stress caused by reactive oxygen species (ROS), primarily triggered by uncontrolled high blood sugar levels in diabetes. Antioxidants like vitamin C, E, selenium, and alpha-lipoic acid, when used as supplements, have shown promise in reducing oxidative stress markers and improving antioxidant status in laboratory and animal studies and diabetic patients. Antioxidant supplementation may help reduce the risk of diabetic complications such as neuropathy, nephropathy, retinopathy, and cardiovascular disease. Additionally, antioxidants also have anti-inflammatory properties, which could be beneficial in reducing inflammation associated with diabetes. Antioxidant supplementation has been shown to enhance endothelial function, insulin sensitivity, and glucose metabolism, thereby aiding in glycemic control and overall diabetic management. Combining antioxidants with certain medications may have therapeutic benefits, such as effectively neutralizing free radicals and enhancing the regulation of antioxidant defense systems. This review presents an update on diabetes, the sources of free radical generation, the body's natural defense mechanisms, the clinical evidence regarding using antioxidants in managing diabetic complications, and the potential new therapeutic approaches. Overall, antioxidant supplementation may offer some benefits in managing diabetic complications. However, further studies are needed to understand the mechanisms of action, determine the optimal supplementation, explore potential interactions with other medications, and conduct long-term studies to establish the possible use of antioxidants for optimal benefits in diabetes care.

Exploring the key role of DNA methylation as an epigenetic modulator in oxidative stress related islet cell injury in patients with type 2 diabetes mellitus: a review

Type 2 diabetes mellitus (T2DM) is a multifactorial metabolic disorder characterised by impaired insulin secretion and action, often exacerbated by oxidative stress. Recent research has highlighted the intricate involvement of epigenetic mechanisms, particularly DNA methylation, in the pathogenesis of T2DM. This review aims to elucidate the role of DNA methylation as an epigenetic modifier in oxidative stress-mediated beta cell dysfunction, a key component of T2DM pathophysiology. Oxidative stress, arising from an imbalance between reactive oxygen species (ROS) production and antioxidant defence mechanisms, is a hallmark feature of T2DM. Beta cells, responsible for insulin secretion, are particularly vulnerable to oxidative damage due to their low antioxidant capacity. Emerging evidence suggests that oxidative stress can induce aberrant DNA methylation patterns in beta cells, leading to altered gene expression profiles associated with insulin secretion and cell survival. Furthermore, studies have identified specific genes involved in beta cell function and survival that undergo DNA methylation changes in response to oxidative stress in T2DM. These epigenetic modifications can perpetuate beta cell dysfunction by dysregulating key pathways essential for insulin secretion, such as the insulin signalling cascade and mitochondrial function. Understanding the interplay between DNA methylation, oxidative stress, and beta cell dysfunction holds promise for developing novel therapeutic strategies for T2DM. Targeting aberrant DNA methylation patterns may offer new avenues for restoring beta cell function and improving glycemic control in patients with T2DM. However, further research is needed to elucidate the complex mechanisms underlying epigenetic regulation in T2DM and to translate these findings into clinical interventions.

Dysregulation of pancreatic β-cell autophagy and the risk of type 2 diabetes

Macroautophagy/autophagy is an essential degradation process that removes abnormal cellular components, maintains homeostasis within cells, and provides nutrition during starvation. Activated autophagy enhances cell survival during stressful conditions, although overactivation of autophagy triggers induction of autophagic cell death. Therefore, early-onset autophagy promotes cell survival whereas late-onset autophagy provokes programmed cell death, which can prevent disease progression. Moreover, autophagy regulates pancreatic β-cell functions by different mechanisms, although the precise role of autophagy in type 2 diabetes (T2D) is not completely understood. Consequently, this mini-review discusses the protective and harmful roles of autophagy in the pancreatic β cell and in the pathophysiology of T2D.

Monocarbonyl analogs of curcumin C66 and B2BrBC modulate oxidative stress, JNK activity, and pancreatic gene expression in rats with streptozotocin-induced diabetes

The pathogenesis of type 1 diabetes mellitus (T1DM) involves oxidative stress and inflammation. Curcumin, a natural polyphenolic compound found in turmeric, known to exhibit antioxidative and anti-inflammatory properties, is characterized by poor chemical stability, low bioavailability, and rapid metabolism. Monocarbonyl analogs of curcumin (MACs) with a structural absence of β-diketone and enhanced stability and bioavailability present a potential solution to the challenges associated with the use of curcumin. This study aimed to evaluate the effect of two MACs, C66 and B2BrBC, on oxidative stress markers, antioxidant enzyme activity, expression of diabetes-associated genes, and signaling pathway proteins in the context of T1DM. Streptozotocin (STZ)-induced male Wistar rats or rat pancreatic RIN-m cells were used for in vivo and in vitro experiments, respectively. C66 or B2BrBC were given either before or after STZ treatment. Oxidative stress markers and antioxidant enzyme activities were determined in various tissues. Expression of diabetes-associated genes was assessed using RT-qPCR, and the activity of signaling pathway proteins in the pancreas was determined through Western blot analysis. Treatment with C66 and B2BrBC significantly reduced oxidative stress markers and positively influenced antioxidant enzyme activities. Moreover, both compounds inhibited JNK activity in the pancreas while enhancing the expression of genes crucial for β-cell survival and glucose and redox homeostasis. The findings highlight the multifaceted potential of C66 and B2BrBC in ameliorating oxidative stress, influencing gene expression patterns linked to diabetes, and modulating key signaling pathways in the pancreas. The findings suggest that these compounds can potentially address diabetes-related pathological processes.

Advancing diabetes management: Exploring pancreatic beta-cell restoration's potential and challenges

Diabetes mellitus, characterized by chronic hyperglycemia due to insulin deficiency or resistance, poses a significant global health burden. Central to its pathogenesis is the dysfunction or loss of pancreatic beta cells, which are res-ponsible for insulin production. Recent advances in beta-cell regeneration research offer promising strategies for diabetes treatment, aiming to restore endogenous insulin production and achieve glycemic control. This review explores the physiological basis of beta-cell function, recent scientific advan-cements, and the challenges in translating these findings into clinical applications. It highlights key developments in stem cell therapy, gene editing technologies, and the identification of novel regenerative molecules. Despite the potential, the field faces hurdles such as ensuring the safety and long-term efficacy of regen-erative therapies, ethical concerns around stem cell use, and the complexity of beta-cell differentiation and integration. The review highlights the importance of interdisciplinary collaboration, increased funding, the need for patient-centered approaches and the integration of new treatments into comprehensive care strategies to overcome these challenges. Through continued research and collaboration, beta-cell regeneration holds the potential to revolutionize diabetes care, turning a chronic condition into a manageable or even curable disease.

NADPH oxidase 5 is a novel susceptibility gene for type 2 diabetes mellitus

OBJECTIVE

This pilot study investigated whether single nucleotide polymorphisms (SNP) in the NOX5 gene (NADPH oxidase 5) are associated with the type 2 diabetes (T2D) risk.

SUBJECTS AND METHODS

A total of 1579 patients with T2D and 1627 age- and sex-matched healthy subjects were recruited for this study. Genotyping of common SNPs, namely rs35672233, rs3743093, rs2036343, rs311886, and rs438866, was performed using the MassArray-4 system.

RESULTS

SNP rs35672233 was associated with an increased risk of T2D (OR = 1.67, 95% CI 1.29-2.17, FDR = 0.003). The H3 haplotype (rs35672233T-rs3743093G-rs2036343A-rs311886C-rs438866C) increased T2D risk (OR = 1.65, 95% CI 1.27-2.13, FDR = 0.001). The rs35672233 polymorphism and H3 haplotype were found to have an association with T2D risk only in subjects with a body mass index greater than 25 kg/m2 (FDR < 0.01). Environmental risk factors, such as chronic psycho-emotional stress, sedentary lifestyle, high-calorie diet and SNP rs35672233 were jointly associated with T2D susceptibility. A haplotype comprising the allele rs35672233-C and conferring protection against T2D, was associated with elevated levels of antioxidants such as total glutathione and uric acid, as well as reduced levels of two-hour postprandial glucose in the plasma of patients. The NOX5 polymorphisms showed no associations with diabetic complications.

CONCLUSION

The present study is the first to establish associations between polymorphisms in NOX5 and the risk of type 2 diabetes mellitus, and provides a new line of evidence for the crucial role of oxidative stress-related genes in disease susceptibility.

Encapsulation of telmisartan inside insulinoma-cell-derived extracellular vesicles outperformed biomimetic nanovesicles in modulating the pancreatic inflammatory microenvironment

Diabetes mellitus (DM) is a chronic metabolic condition, characterized by hyperglycaemia, oxidative imbalance, pancreatic β-cell death, and insulin insufficiency. Angiotensin II (Ang II) increases oxidative stress, inflammation, and apoptosis, and Ang II type 1 receptor (AT1R) blockers (ARBs) can ameliorate inflammatory response and oxidative stress. However, like other small-molecule drugs, free ARBs show poor in vivo efficacy and dose-limiting toxicities. Hence, in this study, we developed nano-formulations of telmisartan (TEL), an ARB, by encapsulating it inside a murine insulinoma cell-derived extracellular vesicle (nanoTEL) and a bio-mimetic lipid nanovesicle (lipoTEL). Both nano-formulations showed spherical morphology and sustained release of TEL. In vitro, nanoTEL restored oxidative equilibrium, attenuated reactive oxygen species levels, enhanced the uptake of glucose analogue, and increased the expression of glucose transporter protein 4 better than lipoTEL. In a streptozotocin-induced murine model of diabetes, nanoTEL lowered blood glucose levels, improved glucose tolerance, and promoted insulin synthesis and secretion significantly better than lipoTEL. Moreover, nanoTEL was found superior in ameliorating the pancreatic inflammatory microenvironment by regulating NF-κBp65, HIF-1α, and PPAR-γ expression; modulating IL-1β, IL-6, tumor necrosis factor-α, IL-10, and IL-4 levels and inducing the polarization of macrophage from M1 to M2. Further, nanoTEL administration induced angiogenesis and promoted the proliferation of pancreatic cells to restore the structural integrity of the islets of Langerhans more efficiently than lipoTEL. These findings collectively suggest that nanoTEL outperforms lipoTEL in restoring the function of pancreatic β-cells by modulating the pancreatic inflammatory microenvironment and show potential for the treatment of DM.

Decoding the immune dance: Unraveling the interplay between beta cells and type 1 diabetes

BACKGROUND

Type 1 diabetes (T1D) is an autoimmune disease characterized by the specific destruction of insulin-producing beta cells in the pancreas by the immune system, including CD4 cells which orchestrate the attack and CD8 cells which directly destroy the beta cells, resulting in the loss of glucose homeostasis.

SCOPE OF REVIEW

This comprehensive document delves into the complex interplay between the immune system and beta cells, aiming to shed light on the mechanisms driving their destruction in T1D. Insights into the genetic predisposition, environmental triggers, and autoimmune responses provide a foundation for understanding the autoimmune attack on beta cells. From the role of viral infections as potential triggers to the inflammatory response of beta cells, an intricate puzzle starts to unfold. This exploration highlights the importance of beta cells in breaking immune tolerance and the factors contributing to their targeted destruction. Furthermore, it examines the potential role of autophagy and the impact of cytokine signaling on beta cell function and survival.

MAJOR CONCLUSIONS

This review collectively represents current research findings on T1D which offers valuable perspectives on novel therapeutic approaches for preserving beta cell mass, restoring immune tolerance, and ultimately preventing or halting the progression of T1D. By unraveling the complex dynamics between the immune system and beta cells, we inch closer to a comprehensive understanding of T1D pathogenesis, paving the way for more effective treatments and ultimately a cure.

Metabolic Stress Levels Influence the Ability of Myelin Transcription Factors to Regulate β-Cell Identity and Survival

A hallmark of type 2 diabetes (T2D) is endocrine islet β-cell failure, which can occur via cell dysfunction, loss of identity, and/or death. How each is induced remains largely unknown. We used mouse β-cells deficient for myelin transcription factors (Myt TFs; including Myt1, -2, and -3) to address this question. We previously reported that inactivating all three Myt genes in pancreatic progenitor cells (MytPancΔ) caused β-cell failure and late-onset diabetes in mice. Their lower expression in human β-cells is correlated with β-cell dysfunction, and single nucleotide polymorphisms in MYT2 and MYT3 are associated with a higher risk of T2D. We now show that these Myt TF-deficient postnatal β-cells also dedifferentiate by reactivating several progenitor markers. Intriguingly, mosaic Myt TF inactivation in only a portion of islet β-cells did not result in overt diabetes, but this created a condition where Myt TF-deficient β-cells remained alive while activating several markers of Ppy-expressing islet cells. By transplanting MytPancΔ islets into the anterior eye chambers of immune-compromised mice, we directly show that glycemic and obesity-related conditions influence cell fate, with euglycemia inducing several Ppy+ cell markers and hyperglycemia and insulin resistance inducing additional cell death. These findings suggest that the observed β-cell defects in T2D depend not only on their inherent genetic/epigenetic defects but also on the metabolic load.

ARTICLE HIGHLIGHTS

Sustained linagliptin administration: superior glycemic control and less pancreatic injury in diabetic rats

While linagliptin is the most potent dipeptidyl peptidase 4 inhibitor, its use is limited due to poor bioavailability and the potential risk of pancreatic injury. Here, we investigated whether the sustained weekly administration of linagliptin could provide better effect compared to frequent daily oral administration. Type 2 diabetes was induced by feeding rats a high fructose/fat/salt diet followed by STZ injection. Compared to the partial glycemic control achieved with daily oral linagliptin, a weekly subcutaneous injection containing about one-fourth of the oral dose produced superior glycemic control, as evidenced by the 4-week postprandial glucose follow-up and oral glucose tolerance test. This was confirmed by the significant increase in serum insulin in the case of the sustained linagliptin administration. Higher levels of the anti-inflammatory cytokine adiponectin and lower triglyceride levels were observed after sustained linagliptin administration compared with daily oral linagliptin. In addition, sustained linagliptin displayed a significant increase in β-cells' insulin immunoreactivity when compared with daily linagliptin. More reduction in collagen deposition and caspase-3 immunoreactivity in pancreatic tissue were observed in sustained linagliptin compared with oral linagliptin. In conclusion, sustained linagliptin administration provided superior glycemic control, which seems to be mediated by more reduction in pancreatic injury.

Molecular Insights on Coffee Components as Chemical Antioxidants

Coffee is not only a delicious beverage but also an important dietary source of natural antioxidants. We live in a world where it is impossible to avoid pollution, stress, food additives, radiation, and other sources of oxidants that eventually lead to severe health disorders. Fortunately, there are chemicals in our diet that counteract the hazards posed by the reactive species that trigger oxidative stress. They are usually referred to as antioxidants; some of them can be versatile compounds that exert such a role in many ways. This review summarizes, from a chemical point of view, the antioxidant effects of relevant molecules found in coffee. Their mechanisms of action, trends in activity, and the influence of media and pH in aqueous solutions, are analyzed. Structure-activity relationships are discussed, and the protective roles of these compounds are examined. A particular section is devoted to derivatives of some coffee components, and another one to their bioactivity. The data used in the analysis come from theoretical and computational protocols, which have been proven to be very useful in this context. Hopefully, the information provided here will pro-mote further investigations into the amazing chemistry contained in our morning coffee cup.   Resumen. El café no solo es una bebida deliciosa, sino también una importante fuente dietética de antioxidantes naturales. Vivimos en un mundo donde es imposible evitar la contaminación, el estrés, los aditivos alimentarios, la radiación y otras fuentes de oxidantes que eventualmente conducen a trastornos de salud graves. Afortunadamente, existen sustancias químicas en nuestra dieta que contrarrestan los peligros planteados por las especies reactivas que desencadenan el estrés oxidativo. Por lo general, se les denomina antioxidantes; algunos de ellos pueden ser compuestos versátiles que ejercen dicho papel de muchas maneras. Este artículo de revisión resume, desde un punto de vista químico, los efectos antioxidantes de moléculas relevantes encontradas en el café. Se analizan sus mecanismos de acción, tendencias en la actividad y la influencia del medio y el pH en soluciones acuosas. Se discuten las relaciones estructura-actividad, y se examinan los roles protectores de estos compuestos. Se dedica una sección particular a los derivados de algunos componentes del café, y otra a su bioactividad. Los datos utilizados en el análisis provienen de protocolos teóricos y computacionales, que han demostrado ser muy útiles en este contexto. Se espera que la información proporcionada aquí promueva investigaciones futuras sobre la química contenida en nuestra taza de café matutina.

Pharmacology of P2X Receptors and Their Possible Therapeutic Potential in Obesity and Diabetes

The role of P2X ionotropic receptors in the behavior of purinergic signaling on pathophysiological processes has been widely studied. In recent years, the important participation of P2X receptors in physiological and pathological processes, such as energy metabolism, characteristic inflammatory responses of the immune system, and nociceptive activity in response to pain stimuli, has been noted. Here, we explore the molecular characteristics of the P2X receptors and the use of the different agonist and antagonist agents recently described, focusing on their potential as new therapeutic targets in the treatment of diseases with emphasis on obesity, diabetes, and some of the complications derived from these pathologies.

Mendelian randomization analysis reveals causal effects of blood lipidome on gestational diabetes mellitus

BACKGROUND

Observational studies have revealed associations between maternal lipid metabolites and gestational diabetes mellitus (GDM). However, whether these associations are causal remain uncertain.

OBJECTIVE

To evaluate the causal relationship between lipid metabolites and GDM.

METHODS

A two-sample Mendelian randomization (MR) analysis was performed based on summary statistics. Sensitivity analyses, validation analyses and reverse MR analyses were conducted to assess the robustness of the MR results. Additionally, a phenome-wide MR (Phe-MR) analysis was performed to evaluate potential side effects of the targeted lipid metabolites.

RESULTS

A total of 295 lipid metabolites were included in this study, 29 of them had three or more instrumental variables (IVs) suitable for sensitivity analyses. The ratio of triglycerides to phosphoglycerides (TG_by_PG) was identified as a potential causal biomarker for GDM (inverse variance weighted (IVW) estimate: odds ratio (OR) = 2.147, 95% confidential interval (95% CI) 1.415-3.257, P = 3.26e-4), which was confirmed by validation and reverse MR results. Two other lipid metabolites, palmitoyl sphingomyelin (d18:1/16:0) (PSM(d18:1/16:0)) (IVW estimate: OR = 0.747, 95% CI 0.583-0.956, P = 0.021) and triglycerides in very small very low-density lipoprotein (XS_VLDL_TG) (IVW estimate: OR = 2.948, 95% CI 1.197-5.215, P = 0.015), were identified as suggestive potential biomarkers for GDM using a conventional cut-off P-value of 0.05. Phe-MR results indicated that lowering TG_by_PG had detrimental effects on two diseases but advantageous effects on the other 13 diseases.

CONCLUSION

Genetically predicted elevated TG_by_PG are causally associated with an increased risk of GDM. Side-effect profiles indicate that TG_by_PG might be a target for GDM prevention, though caution is advised due to potential adverse effects on other conditions.

Probiotics for pancreatic β-cell function: from possible mechanism of action to assessment of effectiveness

Type 2 diabetes (T2D) is a metabolic disease characterized by chronic hyperglycemia because of insulin resistance (IR) and\or pancreatic β-cell dysfunction. Last century research showed that gut microbiota has a direct effect on metabolism and metabolic diseases. New studies into the human microbiome and its connection with the host is making it possible to develop new therapies for a wide variety of diseases. Inflammation is a well-known precursor to metabolic syndrome, which increases the risk of hypertension, visceral obesity, and dyslipidemia, which can lead to T2D through the damage of pancreatic β-cell and reduce insulin secretion. Current understanding for beneficial effects of probiotics in T2D strictly rely on both animal and clinical data, which mostly focused on their impact on IR, anthropometric parameters, glycemic control and markers of chronic systemic inflammation. From the other hand, there is a lack of evidence-based probiotic efficacy on pancreatic β-cell function in terms of T2D and related metabolic disorders. Therefore, current review will focus on the efficacy of probiotics for the protection of β-cells damage and it`s mechanism in patients with T2D.

Exploring sesquiterpene lactone as a dual therapeutic agent for diabetes and oxidative stress: insights into PI3K/AKT modulation

Diabetic mellitus (DM) is characterized by hyperglycaemia and defective macromolecular metabolism, arising from insulin resistance or lack of insulin production. The present study investigates the potential of artemisinin, a sesquiterpene lactone isolated from Artemisia annua, to exert anti-diabetic and antioxidant effects through modulation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signalling pathway. Our computational analyses demonstrated a high binding affinity of artemisinin with proteins belonging to the PI3K/AKT signalling cascade. α-Amylase and α-glucosidase studies revealed a notable increase in inhibition percentages with artemisinin treatment across concentrations ranging from 10 to 160 µM. A similar significant (p < 0.05) dose-dependent inhibition of free radicals was observed for the in vitro anti-oxidant assays. Further, toxicological profiling of artemisinin in the in vivo zebrafish embryo-larvae model from 4 to 96 h post-fertilization (hpf) did not exhibit any harmful repercussions. In addition, gene expression investigations confirmed artemisinin's potential mechanism in modulating hyperglycaemia and oxidative stress through the regulation of the PI3K/AKT pathway. Overall, our investigation suggests that artemisinin can be used as a therapeutic intervention for diabetes and oxidative stress, opening up opportunities for future investigation in clinical settings.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-04050-2.

Therapeutic effect of oral insulin-chitosan nanobeads pectin-dextrin shell on streptozotocin-diabetic male albino rats

The current study inspects the therapeutic effects of orally ingested insulin-loaded chitosan nanobeads (INS-CsNBs) with a pectin-dextrin (PD) coating on streptozotocin (STZ)-induced diabetes in Wistar rats. The study also assessed antioxidant effects in pancreatic tissue homogenate, insulin, C-peptide, and inflammatory markers interleukin-1 beta and interleukin-6 (IL-1β and IL-6) in serum. Additionally, histopathological and immunohistochemical examination of insulin granules, oxidative stress, nuclear factor kappa B (NF-κB P65), and sirtuin-1 (SIRT-1) protein detection, as well as gene expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), B-cell lymphoma 2 (Bcl2), and Bcl-2-associated X protein (Bax) in pancreatic tissue were investigated. After induction of diabetes with STZ, rats were allocated into 6 groups: the normal control (C), the diabetic control (D), and the diabetic groups treated with INS-CsNBs coated with PD shell (50 IU/kg) (NF), free oral insulin (10 IU/kg) (FO), CsNBs-PD shell (50 IU/kg) (NB), and subcutaneous insulin (10 IU/kg) (Sc). The rats were treated daily for four weeks. Treatment of diabetic rats with INS-CsNBs coated with PD shell resulted in a significant improvement in blood glucose levels, elevated antioxidant activities, decreased NF-κB P65, IL-1β, and IL-6 levels, upregulated Nrf-2 and HO-1, in addition to a marked improvement in the histological architecture and integrity compared to the diabetic group. The effects of oral INS-CsNBs administration were comparable to those of subcutaneous insulin. In conclusion, oral administration of INS-loaded Cs-NBs with a pectin-dextrin shell demonstrated an ameliorative effect on STZ-induced diabetes, avoiding the drawbacks of subcutaneous insulin.

The cellular and molecular targets of natural products against metabolic disorders: a translational approach to reach the bedside

Metabolic disorders, including obesity, dyslipidemia, diabetes, nonalcoholic fatty liver disease, and metabolic syndrome, are characterized by insulin resistance, abnormalities in circulating cholesterol and lipid profiles, and hypertension. The most common pathophysiologies of metabolic disorders are glucose/lipid metabolism dysregulation, insulin resistance, inflammatory response, and oxidative stress. Although several agents have been approved for the treatment of metabolic disorders, there is still a strong demand for more efficacious drugs with less side effects. Natural products have been critical sources of drug research and discovery for decades. However, the usefulness of bioactive natural products is often limited by incomplete understanding of their direct cellular targets. In this review, we highlight the current understanding of the established and emerging molecular mechanisms of metabolic disorders. We further summarize the therapeutic effects and underlying mechanisms of natural products on metabolic disorders, with highlights on their direct cellular targets, which are mainly implicated in the regulation of glucose/lipid metabolism, insulin resistance, metabolic inflammation, and oxidative stress. Finally, this review also covers the clinical studies of natural products in metabolic disorders. These progresses are expected to facilitate the application of these natural products and their derivatives in the development of novel drugs against metabolic disorders.

High-Altitude Medicinal Plants as Promising Source of Phytochemical Antioxidants to Combat Lifestyle-Associated Oxidative Stress-Induced Disorders

Oxidative stress, driven by reactive oxygen, nitrogen, and sulphur species (ROS, RNS, RSS), poses a significant threat to cellular integrity and human health. Generated during mitochondrial respiration, inflammation, UV exposure and pollution, these species damage cells and contribute to pathologies like cardiovascular issues, neurodegeneration, cancer, and metabolic syndromes. Lifestyle factors exert a substantial influence on oxidative stress levels, with mitochondria emerging as pivotal players in ROS generation and cellular equilibrium. Phytochemicals, abundant in plants, such as carotenoids, ascorbic acid, tocopherols and polyphenols, offer diverse antioxidant mechanisms. They scavenge free radicals, chelate metal ions, and modulate cellular signalling pathways to mitigate oxidative damage. Furthermore, plants thriving in high-altitude regions are adapted to extreme conditions, and synthesize secondary metabolites, like flavonoids and phenolic compounds in bulk quantities, which act to form a robust antioxidant defence against oxidative stress, including UV radiation and temperature fluctuations. These plants are promising sources for drug development, offering innovative strategies by which to manage oxidative stress-related ailments and enhance human health. Understanding and harnessing the antioxidant potential of phytochemicals from high-altitude plants represent crucial steps in combating oxidative stress-induced disorders and promoting overall wellbeing. This study offers a comprehensive summary of the production and physio-pathological aspects of lifestyle-induced oxidative stress disorders and explores the potential of phytochemicals as promising antioxidants. Additionally, it presents an appraisal of high-altitude medicinal plants as significant sources of antioxidants, highlighting their potential for drug development and the creation of innovative antioxidant therapeutic approaches.

Associations Between Dietary Intake of Tomato and Lycopene with All-Cause and Cancer-Specific Mortality in US Adults with Diabetes: Results From a Cohort Study

This study aimed to explore the association between dietary intake of tomatoes and lycopene with all-cause and cancer mortality among US adults with diabetes. We hypothesized that a higher intake of tomato and lycopene is related to a reduced risk of all-cause and cancer mortality among adults with diabetes. This prospective study was conducted among 9213 US adults with diabetes using data from the National Health and Nutrition Examination Survey (NHANES) 2007-2016. Data on dietary intake of tomatoes and lycopene were obtained from two 24-h dietary recalls. Multivariate Cox proportional hazard models determined the associations between tomato/lycopene intake and mortality. A higher intake of tomatoes and lycopene was significantly associated with a lower risk of all-cause mortality (tomato: Q5 vs. Q1: HR = 0.68, 95% CI = 0.54-0.86, p = 0.001, p for trend = 0.001; lycopene: Q5 vs. Q1: HR = 0.78, 95% CI = 0.64-0.95, p = 0.013, p for trend = 0.006) after adjusting for all covariates. Compared with the lowest quintile of tomato and lycopene intake, the highest quintile was associated with a lower risk of cancer mortality (tomato: HR = 0.58, 95% CI = 0.35-0.96, p = 0.035; lycopene: HR = 0.63, 95% CI = 0.40-0.98, p = 0.043). Our study demonstrated that dietary intake of tomatoes and lycopene was significantly associated with a lower risk of all-cause mortality in US adults with diabetes. High consumption of tomatoes and lycopene was also related to reduced cancer mortality in US adults with diabetes.

Gene expression patterns and DNA methylation of neuron and pancreatic β-cell developments in zebrafish embryos treated with bisphenol F and AF

Bisphenol F (BPF) and bisphenol AF (BPAF) are structural analogues of bisphenol A (BPA) that are used in the manufacture of a myriad of BPA-free products; however, there is a paucity of information regarding their developmental effects. The present study investigates the effects of BPF and BPAF on neurodevelopment and pancreatic β-cell differentiation via altering DNA methylation and gene expression patterns using the zebrafish model. BPF and BPAF induced behavioral perturbations: increased average speed, increased maximum acceleration, increased mania time and decreased static time, in 0.3 and 1.0 μM groups in zebrafish embryos. Glucose level was significantly increased in 1.0 μM BPF (28 %); while a monotonic increase of 29 %, 55 %, and 74 % were observed in 0.1, 0.3, and 1.0 μM BPAF, respectively. Consistent with a decreased insulin mRNA level, the expression of two critical transcription factors (pdx-1 and foxa2) essential for the development and functioning of beta-cells decreased following the bisphenols exposure. In addition, embryonic exposure to BPF and BPAF upregulated the transcription of developmental genes (vegfa, wnt8a, and mstn1) and neuron-related genes (mbp, elavl3, gap43, gfap). Also, the expressions of DNA methyltransferases (dnmt1, dnmt3, dnmt4, dnmt5, dnmt6, dnmt7, and dnmt8) were significantly aberrant compared with the control group. The Bisulfite PCR results indicate increased DNA methylation at promoter regions of pdx-1 in BPF (8.2 %) and BPAF (7.6 %); α1-tubulin in BPF (5.3 %) and in BPAF (4.1 %), congruous with the increased dnmt1 and dnmt3 transcription, at early stage of zebrafish development. The present study indicates that zebrafish embryonic exposure to BPF and BPAF elicits islet dysfunction and neuron perturbations resulting in increased DNA methylation levels.

Insights into the phytochemical profiling, antidiabetic and antioxidant potentials of Lepionurus sylvestris Blume extract in fructose/streptozotocin-induced diabetic rats

In this study, the antidiabetic activities of Lepionurus sylvestris Blume extract (LSB) in rats was investigated. The in vitro antidiabetic properties of LSB was evaluated using α-amylase, α-glucosidase and DPP-IV inhibitory assays, while the antioxidant assay was analysed using DPPH, ABTS and FRAP assays. Type 2 diabetes was with high-fructose/streptozotocin, and the diabetic animals were treated with LSB for 5 weeks. At the end of the experiment, the effects of LSB were evaluated via insulin level, lipid profile and hepatorenal function biomarkers. The level of oxido-inflammatory parameters, histopathology and insulin immunohistochemical staining in the pancreas was evaluated. Diabetic rats manifested significant increases in the blood glucose level, food/water intake, lipid profiles, hepatorenal function biomarkers, as well as a marked decreases in the body weight and serum insulin levels. Histopathological and insulin immunohistochemical examination also revealed decreased pancreatic beta cells and insulin positive cells, respectively. These alterations were associated with significant increases in malondialdehyde, TNF-α and IL-1β, in addition to significant declines in GSH, SOD and CAT activities. LSB significantly reduced blood glucose level, glucose intolerance, serum lipids, restored altered hepatorenal and pancreatic functions in the treated diabetic rats. Further, LSB showed antioxidant and anti-inflammatory activities by reducing malondialdehyde, TNF-α, IL-1β, and increasing antioxidant enzymes activities in the pancreatic tissues. A total of 77 secondary metabolites were tentatively identified in the UPLC-Q-TOF-MS analysis of LSB. Overall, these findings provides insight into the potentials of LSB as an antidiabetic agent which may be associated to the plethora bioactive compounds in the plant.

Atf4 protects islet β-cell identity and function under acute glucose-induced stress but promotes β-cell failure in the presence of free fatty acid

Glucolipotoxicity, caused by combined hyperglycemia and hyperlipidemia, results in β-cell failure and type 2 diabetes (T2D) via cellular stress-related mechanisms. Activating transcription factor 4 (Atf4) is an essential effector of stress response. We show here that Atf4 expression in β-cells is dispensable for glucose homeostasis in young mice, but it is required for β-cell function during aging and under obesity-related metabolic stress. Henceforth, aged Atf4- deficient β-cells display compromised secretory function under acute hyperglycemia. In contrast, they are resistant to acute free fatty acid-induced loss-of identity and dysfunction. At molecular level, Atf4 -deficient β-cells down-regulate genes involved in protein translation, reducing β-cell identity gene products under high glucose. They also upregulate several genes involved in lipid metabolism or signaling, likely contributing to their resistance to free fatty acid-induced dysfunction. These results suggest that Atf4 activation is required for β-cell identity and function under high glucose, but this paradoxically induces β-cell failure in the presence of high levels of free fatty acids. Different branches of Atf4 activity could be manipulated for protecting β-cells from metabolic stress-induced failure.

Highlights

Atf4 is dispensable in β-cells in young miceAtf4 protects β-cells under high glucoseAtf4 exacerbate fatty acid-induced β-cell defectsAtf4 activates translation but depresses lipid-metabolism.

Impact of coffee and its bioactive compounds on the risks of type 2 diabetes and its complications: A comprehensive review

BACKGROUND

Coffee beans have a long history of use as traditional medicine by various indigenous people. Recent focus has been given to the health benefits of coffee beans and its bioactive compounds. Research on the bioactivities, applications, and effects of processing methods on coffee beans' phytochemical composition and activities has been conducted extensively. The current review attempts to provide an update on the biological effects of coffee on type 2 diabetes (T2D) and its comorbidities.

METHODS

Comprehensive literature search was carried out on peer-reviewed published data on biological activities of coffee on in vitro, in vivo and epidemiological research results published from January 2015 to December 2022, using online databases such as PubMed, Google Scholar and ScienceDirect for our searches.

RESULTS

The main findings were: firstly, coffee may contribute to the prevention of oxidative stress and T2D-related illnesses such as cardiovascular disease, retinopathy, obesity, and metabolic syndrome; secondly, consuming up to 400 mg/day (1-4 cups per day) of coffee is associated with lower risks of T2D; thirdly, caffeine consumed between 0.5 and 4 h before a meal may inhibit acute metabolic rate; and finally, both caffeinated and decaffeinated coffee are associated with reducing the risks of T2D.

CONCLUSION

Available evidence indicates that long-term consumption of coffee is associated with decreased risk of T2D and its complications as well as decreased body weight. This has been attributed to the consumption of coffee with the abundance of bioactive chemicals.

Role of IRE1α/XBP1/CHOP/NLRP3 Signalling Pathway in Neonicotinoid Imidacloprid-Induced Pancreatic Dysfunction in Rats and Antagonism of Lycopene: In Vivo and Molecular Docking Simulation Approaches

Imidacloprid (IMI) is a commonly used new-generation pesticide that has numerous harmful effects on non-targeted organisms, including animals. This study analysed both the adverse effects on the pancreas following oral consumption of imidacloprid neonicotinoids (45 mg/kg daily for 30 days) and the potential protective effects of lycopene (LYC) administration (10 mg/kg/day for 30 days) with IMI exposure in male Sprague-Dawley rats. The apoptotic, pyroptotic, inflammatory, oxidative stress, and endoplasmic reticulum stress biomarkers were evaluated, along with the histopathological alterations. Upon IMI administration, noticeable changes were observed in pancreatic histopathology. Additionally, elevated oxidative/endoplasmic reticulum-associated stress biomarkers, inflammatory, pyroptotic, and apoptotic biomarkers were also observed following IMI administration. LYC effectively reversed these alterations by reducing oxidative stress markers (e.g., MDA) and enhancing antioxidant enzymes (SOD, CAT). It downregulated ER stress markers (IRE1α, XBP1, CHOP), decreased pro-inflammatory cytokines (TNF-α, IL-1β), and suppressed pyroptotic (NLRP3, caspase-1) along with apoptotic markers (Bax, cleaved caspase-3). It also improved the histopathological and ultrastructure alterations brought on by IMI toxicity.