Pathogenesis Of Type 2 Diabetes Mellitus Research Articles

Pharmacological modulation of the hydrogen sulfide (H2 S) system by dietary H2 S-donors: A novel promising strategy in the prevention and treatment of type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) represents the most common age-related metabolic disorder, and its management is becoming both a health and economic issue worldwide. Moreover, chronic hyperglycemia represents one of the main risk factors for cardiovascular complications. In the last years, the emerging evidence about the role of the endogenous gasotransmitter hydrogen sulfide (H2 S) in the pathogenesis and progression of T2DM led to increasing interest in the pharmacological modulation of endogenous "H2 S-system". Indeed, H2 S directly contributes to the homeostatic maintenance of blood glucose levels; moreover, it improves impaired angiogenesis and endothelial dysfunction under hyperglycemic conditions. Moreover, H2 S promotes significant antioxidant, anti-inflammatory, and antiapoptotic effects, thus preventing hyperglycemia-induced vascular damage, diabetic nephropathy, and cardiomyopathy. Therefore, H2 S-releasing molecules represent a promising strategy in both clinical management of T2DM and prevention of macro- and micro-vascular complications associated to hyperglycemia. Recently, growing attention has been focused on dietary organosulfur compounds. Among them, garlic polysulfides and isothiocyanates deriving from Brassicaceae have been recognized as H2 S-donors of great pharmacological and nutraceutical interest. Therefore, a better understanding of the therapeutic potential of naturally occurring H2 S-donors may pave the way to a more rational use of these nutraceuticals in the modulation of H2 S homeostasis in T2DM.

Connecting Alzheimer's Disease With Diabetes Mellitus Through Amyloidogenic Evolvability.

Type 2 diabetes mellitus (T2DM) has been clearlylinked to oxidative stress and amylin amyloidosis in pancreatic β-cells. Yet despite extensive investigation, the biological significance of this is not fully understood. Recently, we proposed that Alzheimer’s disease (AD)-relevant amyloidogenic proteins (APs), such as amyloid-β (Aβ) and tau, might be involved in evolvability against diverse stressors in the brain. Given the analogous cellular stress environments shared by both T2DM and AD, the objective of this study is to explore T2DM pathogenesis from the viewpoint of amyloidogenic evolvability. Similar to AD-related APs, protofibrillar amylin might confer resistance against the multiple stressors in β-cells and be transmitted to offspring to deliver stress information, in the absence of which, type 1 DM (T1DM) in offspring might develop. On the contrary, T2DM may be manifested through an antagonistic pleiotropy mechanism during parental aging. Such evolvability-associated processes might be affected by parental diabetic conditions, including T1DM and T2DM. Furthermore, the T2DM-mediated increase in AD risk during aging might be attributed to an interaction of amylin with AD-related APs through evolvability, in which amylin protofibrillar formation presumably caused by adiponectin (APN) resistance could increase protofibril formation of AD-related APs in evolvability and subsequently lead to T2DM promotion of AD through antagonistic pleiotropy in aging. This suggests that targeting APN combined with an anti-T2DM agent might be therapeutic against neurodegeneration. Collectively, T1DM and T2DM might be linked through amylin evolvability, and a better understanding of amyloidogenic evolvability might also reveal clues to therapeutic interventions for AD comorbid with T2DM.

Gene Expression Profiling of Type 2 Diabetes Mellitus by Bioinformatics Analysis.

Objective The aim of this study was to identify the candidate genes in type 2 diabetes mellitus (T2DM) and explore their potential mechanisms. Methods The gene expression profile GSE26168 was downloaded from the Gene Expression Omnibus (GEO) database. The online tool GEO2R was used to obtain differentially expressed genes (DEGs). Gene Ontology (GO) term enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed by using Metascape for annotation, visualization, and comprehensive discovery. The protein-protein interaction (PPI) network of DEGs was constructed by using Cytoscape software to find the candidate genes and key pathways. Results A total of 981 DEGs were found in T2DM, including 301 upregulated genes and 680 downregulated genes. GO analyses from Metascape revealed that DEGs were significantly enriched in cell differentiation, cell adhesion, intracellular signal transduction, and regulation of protein kinase activity. KEGG pathway analysis revealed that DEGs were mainly enriched in the cAMP signaling pathway, Rap1 signaling pathway, regulation of lipolysis in adipocytes, PI3K-Akt signaling pathway, MAPK signaling pathway, and so on. On the basis of the PPI network of the DEGs, the following 6 candidate genes were identified: PIK3R1, RAC1, GNG3, GNAI1, CDC42, and ITGB1. Conclusion Our data provide a comprehensive bioinformatics analysis of genes, functions, and pathways, which may be related to the pathogenesis of T2DM.

Circulating T Cells Exhibit Different TIM3/Galectin-9 Expression in Patients with Obesity and Obesity-Related Diabetes.

Aims Obesity is highly associated with type 2 diabetes mellitus (T2DM). The TIM3/galectin-9 pathway plays an important role in immune tolerance. Herein, we aimed to investigate the expression of TIM3 and galectin-9 in peripheral blood and to evaluate their clinical significance in patients with obesity and obesity-related T2DM. Methods We performed flow cytometry on peripheral blood samples from healthy donors (HC), patients with simple obesity (OB), and patients with obesity comorbid T2DM (OD). The expression of TIM3 on CD3+, CD4+, and CD8+ T cells was determined. The level of galectin-9 in plasma was detected by ELISA. Results We demonstrated the enhancement of TIM3 on CD3+, CD4+, and CD8+ T cells in the OB group when compared with healthy controls, while it was decreased significantly in the OD group. The TIM3+CD8+ T cells of the OB group were positively correlated with risk factors including BMI, body fat rate, and hipline. The concentration of galectin-9 of the OD group in plasma was significantly higher than that of healthy donors and the OB group. Moreover, the level of galectin-9 of the OD group was positively correlated with fasting insulin and C-peptide, which were two clinical features that represented pancreatic islet function in T2DM. Conclusions Our results suggested that TIM3 and galectin-9 may be potential biomarkers related to the pathogenesis of obesity-related T2DM.

Increased serum IL-18 levels and IL-18R expression in newly diagnosed type 2 diabetes mellitus.

Type 2 Diabetes mellitus (T2DM) is a heterogeneous metabolic disorder in which genetic, sedentary lifestyle, obesity, and environmental factors come together to produce insulin resistance in target tissues, leading to hyperglycaemia. Evidence reveals that inflammation may play an essential role in the pathogenesis of T2DM. Interleukin-18 (IL-18), a proinflammatory cytokine, plays a crucial role in the acute and chronic inflammatory process. The association of IL-18 levels with IL-18R expression in T2DM has not been investigated so far. Aim of the study: to compare the peripheral changes in serum IL-18 levels and its receptor (IL18R) expression in newly diagnosed T2DM and healthy controls. A total of 35 newly diagnosed type 2 diabetic cases and 35 non-diabetic controls were enrolled after obtaining informed consent. Venous whole blood was taken under aseptic conditions. Biochemical parameters were estimated in an auto-analyzer. Serum IL-18 levels were calculated using ELISA, whereas IL-18R expression was determined via RT-PCR. GAPDH was used as an internal control. When compared to non-diabetic controls, the serum IL-18 levels were significantly higher in T2DM patients (p=0.010) along with a significant upregulation of IL18R (p=0.0018). Serum IL-18 levels in T2DM and non-diabetic controls were 669.5 (445)and 498.3 (404.9) pg/ml respectively, and IL-18R showed a fold change of 10.33. Both serum IL-18 and its receptor IL-18R is significantly higher in newly diagnosed T2DM patients.

Correlations between inflammatory response, oxidative stress, intestinal pathological damage and intestinal flora variation in rats with type 2 diabetes mellitus.

To explore the correlations between inflammatory response, oxidative stress, intestinal pathological damage, and intestinal flora variation in rats with type 2 diabetes mellitus (T2DM). A total of 80 specific pathogen-free (SPF) male Sprague-Dawley (SD) rats purchased from Beijing Vital River Laboratory Animal Technology Co., Ltd. (Beijiing, China) were randomly divided into two groups, namely T2DM group (n=40) and normal group (n=40). Then, the contents of inflammatory factors [high-sensitivity C-reactive protein (hs-CRP) and tumor necrosis factor-α (TNF-α)] and oxidative stress indicators [malondialdehyde (MDA) and superoxide dismutase (SOD)] were detected. Meanwhile, the distributions of intestinal florae Bifidobacteria, Escherichia coli, Lactobacilli and Enterococcocci and the variation of endotoxin were compared between the two groups. Besides, colon specimens were pathologically examined to observe the occurrence of chronic inflammation variation, intestinal mucosal erosion, intestinal mucosal wall thickening and intestinal mucosal fibrosis. Next, the influences of the glycosylated hemoglobin on levels of hs-CRP, MDA and endotoxin and colonization ability of intestinal florae were analyzed. Additionally, univariate and multivariate analyses were performed for underlying the relations of the pathogenesis of T2DM in rats with their inflammatory response, antioxidant capacity, endotoxin level and intestinal flora colonization capacity. The levels of hs-CRP and TNF-α were significantly higher in T2DM group than those in normal group (p<0.05). T2DM group exhibited an overtly elevated MDA level (p<0.05), and a clearly lowered SOD level (p<0.05) in comparison with normal group. As to intestinal flora-related indicators, the levels of endotoxin, Escherichia coli and Enterococcocci were evidently higher in T2DM group than those in the normal group (p<0.05), while the levels of Bifidobacteria and Lactobacilli in T2DM group were remarkably lowered (p<0.05). Pathological lesions, including chronic inflammation variation, mucosal erosion, mucosal wall thickening and mucosal fibrosis in intestinal mucosal tissues, were worse in T2DM group than those in the normal group (p<0.05). In T2DM rats, the level of glycosylated hemoglobin was positively correlated with changes in the levels of hs-CRP, MDA and endotoxin (p<0.05), and negatively associated with changes in colonization ability of intestinal florae (p<0.05). Aggravated inflammatory response, decreased antioxidant capacity, increased endotoxin level and weakened colonization ability of intestinal florae were independent risk factors for T2DM in rats. Rats with T2DM have significantly aggravated inflammatory response, weakened antioxidant capacity, imbalanced intestinal florae and markedly pathological changes of intestinal mucosa.

Association analysis of HHEX gene variant with type 2 diabetes risk

Type 2 diabetes mellitus (T2DM) is a common, chronic, and complex disorder that is influenced by interactions between genetic and environmental factors. The hematopoietically expressed homeobox (HHEX) gene, which affects insulin sensitivity and secretion, is a candidate gene for the pathogenesis of T2DM. The purpose of this study was to investigate the effect of the HHEX genetic variant, rs1111875, on the T2DM risk in a group of Iranian patients for the first time. A total of 108 T2DM patients and 100 normal subjects were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). There was significant difference in genotypes and alleles frequency of rs1111875 between both case and control groups (p < 0.001). The frequency of the G allele was significantly higher in cases (87.5%) compared with controls (27%) (OR = 18.92, CI = 11.06–32.69, p < 0.001). Our findings suggest that the rs1111875 variant of the HHEX gene could be considered a strong risk factor for T2DM development.

Роль полиморфных маркеров гена IL10 в патогенезе сахарного диабета 1-го типа

Сахарный диабет типа 1 (СД1) представляет собой многофакторное заболевание, которое характеризуется аутоиммунной природой. Важным фактором в патогенезе СД1 является генетическая предрасположенность, характеризующаяся наличием функциональных однонуклеотидных замен (SNP) в генах цитокинов, ответственных за воспаление. Предполагают, что длительное хроническое воспаление приводит к необратимому разрушению β-клеток поджелудочной железы и может быть объяснено наличием функциональных полиморфных маркеров в генах-антагонистах. Цель исследования - изучение частоты аллельных вариантов ряда полиморфных маркеров гена IL10 при СД1 у жителей Москвы и Московской области. Методика. В работу включено 366 больных СД 1 типа и 526 здоровых индивидов русского происхождения. Группу больных составили пациенты с наличием сахарного диабета 1 типа различной манифестации с общей медианой 41±5 лет. Обе группы выравнены по полу и возрасту. Определение генотипов полиморфных маркеров rs1800896, rs1800872 и rs3024505 гена IL10 проводилось с помощью ПЦР «в реальном времени» на амплификаторе «Real-time CFX96 Touch» (Bio-Rad, США) с использованием готовой смеси для ПЦР qPCRmix-HS (Евроген, Россия) и уникальных праймеров и зондов. Результаты. В результате проведенного исследования выявлена статистически значимая ассоциация полиморфного маркера rs1800896 гена IL10 с повышенным риском развития СД1 (χ2=15.52, OR=1.48, CI95%=1.23-1.79, р=0,0004). Заключение. Полученные результаты дополняют информацию о механизмах возникновения СД типа 1. Внедрение в практику анализа полиморфных вариантов гена IL10 позволит выявить предрасположенность к развитию этого заболевания, его прогрессированию у пациентов с аутоиммунными заболеваниями и у лиц, находящихся в группе риска. Type 1 diabetes mellitus (T1DM) is a multifactorial disease of an autoimmune origin. An important factor in the pathogenesis of T1DM is genetic predisposition characterized by the presence of functional single-nucleotide polymorphisms (SNPs) in the cytokine genes contributing to inflammation. Long-standing, chronic inflammation is considered to result in irreversible destruction of all pancreatic b-cells and may be due to the presence of functional polymorphic markers in genes of inflammation antagonists, such as the interleukin 10 (IL10) gene. Aim. The aim of this study was to determine the frequency of allelic variants in a number of IL10 gene polymorphic markers in residents of Moscow and the Moscow Region with T1DM. Methods. The study includes 366 patients with T1DM with different manifestations and a median duration of 41+5 years and 526 healthy individuals. The groups were gender- and age-matched. Genotypes of the rs1800896, rs1800872, and rs3024505 polymorphic markers of the IL10 gene were determined with real-time PCR on a Real-Time CFX96 Touch amplifier (Bio-Rad, USA) with a qPCRmix-HS ready-mixed PCR kit (Eurogen, Russia) and unique primers and probes. Results. The rs1800896 polymorphic marker of the IL10 gene statistically significantly correlated with increased risk of T1DM (χ2=15.52, OR=1.48, CI95%=1.23-1.79, р=0.0004). Conclusion. The study results complement the information about T1DM mechanisms of origin and pathogenesis. Implementation in practice of the methods for analyzing polymorphic variants of the IL10 gene will allow revealing a predisposition to this disease and/or its progression in patients with autoimmune diseases or in people at risk.

The NLRP3 Inflammasome and Its Role in T1DM.

The NLRP3 (nucleotide-binding and oligomerization domain-like receptor family pyrin domain-containing 3) inflammasome is a protein complex expressed in cells. It detects danger signals and induces the production of active caspase-1 and the maturation and release of IL (interleukin)-33, IL-18, IL-1β and other cytokines. T1DM (type 1 diabetes mellitus) is defined as a chronic autoimmune disorder characterized by the autoreactive T cell-mediated elimination of insulin-positive pancreatic beta-cells. Although the exact underlying mechanisms are obscure, researchers have proposed that both environmental and genetic factors are involved in the pathogenesis of T1DM. Furthermore, immune responses, including innate and adaptive immunity, play an important role in this process. Recently, the NLRP3 inflammasome, a critical component of innate immunity, was reported to be associated with T1DM. Here, we review the assembly and function of the NLRP3 inflammasome. In addition, the activation and regulatory mechanisms that enhance or attenuate NLRP3 inflammasome activation are discussed. Finally, we focus on the relationship between the NLRP3 inflammasome and T1DM, as well as its potential value for clinical use.

Exploring Shared Pathogenesis of Alzheimer’s Disease and Type 2 Diabetes Mellitus via Co-expression Networks Analysis

Alzheimer's Disease (AD) and Type 2 Diabetes Mellitus (T2DM) have an increased incidence in modern society. Although increasing evidence has supported the close linkage between these two disorders, the inter-relational mechanisms remain to be fully elucidated. The primary purpose of this study is to explore the shared pathophysiological mechanisms of AD and T2DM. We downloaded the microarray data of AD and T2DM from the Gene Expression Omnibus (GEO) database and constructed co-expression networks by Weighted Gene Co-Expression Network Analysis (WGCNA) to identify gene network modules related to AD and T2DM. Then, Gene Ontology (GO) and pathway enrichment analysis were performed on the common genes existing in the AD and T2DM related modules by clusterProfiler and DOSE package. Finally, we utilized the STRING database to construct the protein-protein interaction network and found out the hub genes in the network. Our findings indicated that seven and four modules were the most significant with AD and T2DM, respectively. Functional enrichment analysis showed that AD and T2DM common genes were mainly enriched in signaling pathways such as circadian entrainment, phagosome, glutathione metabolism and synaptic vesicle cycle. Protein-protein interaction network construction identified 10 hub genes (CALM1, LRRK2, RBX1, SLC6A1, TXN, SNRPF, GJA1, VWF, LPL, AGT) in AD and T2DM shared genes. Our work identified common pathogenesis of AD and T2DM. These shared pathways might provide a novel idea for further mechanistic studies and hub genes that may serve as novel therapeutic targets for diagnosis and treatment of AD and T2DM.

Two to Tango: Dialogue between Adaptive and Innate Immunity in Type 1 Diabetes.

Type 1 diabetes mellitus (T1DM) is a long-term and chronic autoimmune disorder, in which the immune system attacks the pancreatic β-cells. Both adaptive and innate immune systems are involved in T1DM development. Both B-cells and T-cells, including CD4+ and CD8+ T-cells, as well as other T-cell subsets, could affect onset of autoimmunity. Furthermore, cells involved in innate immunity, including the macrophages, dendritic cells, and natural killer (NK) cells, could also accelerate or decelerate T1DM development. In this review, the crosstalk and function of immune cells in the pathogenesis of T1DM, as well as the corresponding therapeutic interventions, are discussed.

Human Leukocyte Antigen-DR Deficiency and Immunosuppression-Related End-Organ Failure in SARS-CoV2 Infection.

Human Leukocyte Antigen-DR Deficiency and Immunosuppression-Related End-Organ Failure in SARS-CoV2 Infection.

Interactions Between Gut Microbiota, Host, and Herbal Medicines: A Review of New Insights Into the Pathogenesis and Treatment of Type 2 Diabetes.

Herbal medicines (HMs) are a major subset of complementary and alternative medicine. They have been employed for the efficient clinical management of type 2 diabetes mellitus (T2DM) for centuries. However, the related underlying mechanisms still remain to be elucidated. It has been found out that microbiota is implicated in the pathogenesis and treatment of T2DM. An interplay between gut microbiota and host occurs mainly at the gastrointestinal mucosal barrier. The host movements influence the composition and abundance of gut microbiota, whereas gut microbiota in turn modulate the metabolic and immunological activities of the host. Intestinal dysbiosis, endotoxin-induced metabolic inflammation, immune response disorder, bacterial components and metabolites, and decreased production of short-chain fatty acids are considered significant pathogenic mechanisms underlying T2DM. The interaction between gut microbiota and HMs during T2DM treatment has been investigated in human, animal, and in vitro studies. HMs regulate the composition of beneficial and harmful bacteria and decrease the inflammation caused by gut microbiota. Furthermore, the metabolism of gut microbiota modulates HM biotransformation. In this review, we have summarized such research findings, with the aim to improve our understanding of the pathogenesis and potential therapeutic mechanisms of HMs in T2DM and to provide new insights into specific targeted HM-based therapies and drug discovery.

Differential Profile of Plasma Circular RNAs in Type 1 Diabetes Mellitus.

BackgroundNo currently available biomarkers or treatment regimens fully meet therapeutic needs of type 1 diabetes mellitus (T1DM). Circular RNA (circRNA) is a recently identified class of stable noncoding RNA that have been documented as potential biomarkers for various diseases. Our objective was to identify and analyze plasma circRNAs altered in T1DM.MethodsWe used microarray to screen differentially expressed plasma circRNAs in patients with new onset T1DM (n=3) and age-/gender-matched healthy controls (n=3). Then, we selected six candidates with highest fold-change and validated them by quantitative real-time polymerase chain reaction in independent human cohort samples (n=12). Bioinformatic tools were adopted to predict putative microRNAs (miRNAs) sponged by these validated circRNAs and their downstream messenger RNAs (mRNAs). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to gain further insights into T1DM pathogenesis.ResultsWe identified 68 differentially expressed circRNAs, with 61 and seven being up- and downregulated respectively. Four of the six selected candidates were successfully validated. Curations of their predicted interacting miRNAs revealed critical roles in inflammation and pathogenesis of autoimmune disorders. Functional relations were visualized by a circRNA-miRNA-mRNA network. GO and KEGG analyses identified multiple inflammation-related processes that could be potentially associated with T1DM pathogenesis, including cytokine-cytokine receptor interaction, inflammatory mediator regulation of transient receptor potential channels and leukocyte activation involved in immune response.ConclusionOur study report, for the first time, a profile of differentially expressed plasma circRNAs in new onset T1DM. Further in silico annotations and bioinformatics analyses supported future application of circRNAs as novel biomarkers of T1DM.

Identification of a Multi-Long Noncoding RNA Signature for the Diagnosis of Type 1 Diabetes Mellitus.

Due to the increasing prevalence of type 1 diabetes mellitus (T1DM) and its complications, there is an urgent need to identify novel methods for predicting the occurrence and understanding the pathogenetic mechanisms of the disease. Accumulated data have demonstrated the potential of long noncoding RNAs (lncRNAs), as biomarkers in establishing diagnosis and predicting prognosis of numerous diseases. Yet, little is known about the expression patterns and regulatory roles of lncRNAs in the pathogenesis of T1DM and whether they can be used as diagnostic biomarkers for the disease. To further explore these questions, in the present study, we conducted a comparative analysis of the expression patterns of lncRNAs between 20 T1DM patients and 42 health controls by retrospectively analyzing a published microarray data set. Our results indicate that, compared with healthy controls, diabetic patients had altered levels of lncRNAs. Then, we used three time cross-validation strategy and support vector machine to propose a specific 26-lncRNA signature (termed 26LncSigT1DM). This 26LncSigT1DM signature can be used to effectively distinguish between healthy and diabetic individuals (area under the curve = 0.825) of a validation cohort. After the 26LncSigT1DM was prospectively validated, we used Pearson correlation to identify 915 mRNAs, whose expression levels were positively correlated with those of the 26 lncRNAs. According to their Gene Ontology annotations, these mRNAs participate in processes including cellular response to stimulus, cell communication, multicellular organismal process, and cell motility. Kyoto Encyclopedia of Genes and Genomes analysis demonstrated that the genes encoding the 915 mRNAs may be associated with the NOD-like receptor signaling pathway, transforming growth factor β signaling pathway, and mineral absorption, suggesting that the deregulation of these lncRNAs may mediate inflammatory abnormalities and immune dysfunctions, which jointly promote the pathogenesis of T1DM. Thus, our study identifies a novel diagnostic tool and may shed more light on the molecular mechanisms underlying the pathogenesis of T1DM.

The Role Of Cd36 In Relieving Lipotoxicity Of Skeletal Muscle Cells In High Free Fatty Acid Environment.

PURPOSE: Lipotoxicity is closely related to the etiology and complications of type 2 diabetes mellitus (T2DM). Lipotoxicity in muscle cells induces insulin resistance, which is a key factor in the pathogenesis of T2DM. This study investigated the protective effect of Fatty Acid Translocase (FAT/CD36) against palmitic acid (PA)- induced lipoapoptosis. METHODS: Cells at ~40-60% confluence were transfected with siCtrl or siCD36 for overnight using Lipofectamine RNAiMAX. Cells were treated with PA at 200μM for 16 h. The PA-induced viability in C2C12 cells was measured by MTT assay; the PA-induced apoptosis in C2C12 cells was monitored by flow cytometry. The differences in means were analyzed by t test. RESULTS: PA treatment increased apoptosis (7.50% ± 0.21% vs. 10.40% ± 1.25%, p < 0.05) and decreased viability (100% ± 2.40% vs. 97.32% ± 3.60%, p < 0.05) in C2C12 cells in contrast to cells that were treated with PA-free media. After 16 h of PA treatment without CD36 protection, C2C12 cells had a significant increase in apoptosis when treated with siCD36 transfection, in contrast to cells that were negative control siRNA transfected (10.40% ± 1.25% vs. 16.04% ± 1.58%, p < 0.05), indicating that the existence of CD36 may protect high PA-induced lipoapoptosis by increasing cell uptake of FFA. Further statistical analysis confirmed a significant increase in the percentage of apoptotic cells both in early stage and late stage when subjected to CD36 deficiency (7.93% ± 0.57% vs. 10.70% ± 1.55%, p < 0.05; 2.47% ± 0.68% vs. 5.34% ± 0.06%, p < 0.05, respectively). CONCLUSIONS: This study demonstrated a novel function of CD36 in preventing lipotoxicity in skeletal muscle cells when subject to high FFA environment, implicating a promising target for obesity and diabetic therapy.

Rice Bran Phenolic Extracts Modulate Insulin Secretion and Gene Expression Associated with β-Cell Function.

Oxidative stress is known to modulate insulin secretion and initiate gene alterations resulting in impairment of β-cell function and type 2 diabetes mellitus (T2DM). Rice bran (RB) phenolic extracts contain bioactive properties that may target metabolic pathways associated with the pathogenesis of T2DM. This study aimed to examine the effect of stabilized RB phenolic extracts on the expression of genes associated with β-cell function such as glucose transporter 2 (Glut2), pancreatic and duodenal homeobox 1 (Pdx1), sirtuin 1 (Sirt1), mitochondrial transcription factor A (Tfam), and insulin 1 (Ins1) in addition to evaluating its impact on glucose-stimulated insulin secretion. It was observed that treatment with different concentrations of RB phenolic extracts (25-250 µg/mL) significantly increased the expression of Glut2, Pdx1, Sirt1, Tfam, and Ins1 genes and glucose-stimulated insulin secretion under both normal and high glucose conditions. RB phenolic extracts favourably modulated the expression of genes involved in β-cell dysfunction and insulin secretion via several mechanisms such as synergistic action of polyphenols targeting signalling molecules, decreasing free radical damage by its antioxidant activity, and stimulation of effectors or survival factors of insulin secretion.

Association analysis of polymorphisms in LEP (rs7799039 and rs2167270) and LEPR (rs1137101) gene towards the development of type 2 diabetes in North Indian Punjabi population.

Obesity is a major risk factor in aetiology of type 2 diabetes mellitus (T2DM). Leptin (LEP) is an anti-obesity hormone which regulates food intake, energy expenditure and glucose metabolism. The genetic variants in leptin and leptin receptor gene (LEPR) may play major role in the pathogenesis of T2DM and obesity. The current study aimed to investigate the association of polymorphisms in LEP (rs7799039, -2548G/A and rs2167270, 19G/A) and LEPR (rs1137101, 668A/G) gene with type 2 diabetes in North Indian Punjabi population. A total of 817 subjects were included for the present case-control study, consisting of 417 T2DM patients and 400 healthy controls. The anthropometric, physiometric and biochemical measurements were taken from all the subjects. The genotyping of LEP and LEPR gene variants were carried out by polymerase chain reaction based restriction fragment length polymorphism method (PCR-RFLP), followed by genotyping of 10% of the samples for each polymorphism by Sanger sequencing method for quality control measurement. The risk genotype frequencies were found to be significantly higher in T2DM cases than control subjects (rs7799039, p=0.001; rs2167270, p=0.019 and rs1137101, p=0.003). Under recessive genetic model LEPrs7799039 and LEPRrs1137101 polymorphism conferred 3.4 and 2.1 fold risk towards the development of T2DM after adjustment of various covariates (OR=3.44, 95%CI: 1.768-6.681, p=0.001 and OR: 2.12, 95%CI: 1.256-3.569, p=0.005, respectively). In the stratified analysis of LEP variant rs7799039 by age, gender, BMI and alcohol use, a significantly increased risk of T2DM was found in female, BMI≥23 and never drinking subgroups. However, in the LEPR variant rs1137101, significantly increased risk of T2DM was observed in age <50, male, BMI≥23 and never drinking subgroup. The A-G haplotype combination of rs7799039A and rs2167270G conferred significant 2 fold risk towards T2DM (OR=2.35, 95%CI: 1.34-4.12, p=0.002). In control group, the genetic variants rs7799039 and rs1137101 were significantly associated with levels of random blood sugar and low density lipoprotein cholesterol levels. The present study revealed the association of LEP rs7799039 and LEPR rs1137101 with type 2 diabetes mellitus, which suggest its predominant role in the estimation of type 2 diabetes mellitus in North Indian Punjabi population.

Quantitative profiling of eicosanoids derived from n-6 and n-3 polyunsaturated fatty acids by twin derivatization strategy combined with LC-MS/MS in patients with type 2 diabetes mellitus

Eicosanoids derived from n-6 and n-3 polyunsaturated fatty acids (PUFAs), serving as important signaling molecules, are implicated in many physiological and pathological processes, including Type 2 diabetes mellitus (T2DM). However, the quantification of endogenous eicosanoids is challenged by high structural similarity, low abundance in biological sample and poor electrospray ionization efficiency. In the current study, a sensitive and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to quantify 65 eicosanoids derived from n-6 and n-3 PUFAs in plasma samples using twin derivatization strategy with a pair of reagents, 5-(dimethylamino) naphthalene-1-sulfonyl piperazine (Dns-PP) and (diethylamino) naphthalene-1-sulfonyl piperazine (Dens-PP). Dns-PP-derivatized plasma sample was mixed with the equal volume of Dens-PP-derivatized eicosanoid internal standards for LC-MS/MS analysis in multiple reaction monitoring (MRM) mode. After Dns-PP derivatization, the ionization efficiency and separation performance were substantially improved, resulting in the enhanced sensitivity by 446- to 1009-folds compared to intact eicosanoids. The quantitative accuracy determined by twin derivatization method was found to be comparable with stable isotope labeled internal standards (SIL-IS) method. The newly proposed method was successfully employed to quantify the target eicosanoids in plasma samples from healthy controls and the patients with T2DM. N-6 PUFA-derived eicosanoids, PGF2α, PGD2, PGE2, PGA2, PGB2, 20-HETE and LTC4, significantly increased in plasma sample of T2DM patients. Oppositely, n-3 PUFA-derived eicosanoids, RvE1, 12(S)-HEPE and RvD1, remarkably decreased. Spearman’s correlation analysis indicated the strong correlations between these highlighted eicosanoids and clinical parameters of T2DM. Collectively, the sensitive and reliable eicosanoid quantification method may facilitate to elucidate the characteristics of eicosanoid metabolism and understand the role of eicosanoids in the pathogenesis of T2DM and other diseases.

Dietary carbohydrates modulate metabolic and β-cell adaptation to high-fat diet-induced obesity.

Obesity is associated with several chronic comorbidities, one of which is type 2 diabetes mellitus (T2DM). The pathogenesis of obesity and T2DM is influenced by alterations in diet macronutrient composition, which regulate energy expenditure, metabolic function, glucose homeostasis, and pancreatic islet cell biology. Recent studies suggest that increased intake of dietary carbohydrates plays a previously underappreciated role in the promotion of obesity and consequent metabolic dysfunction. Thus, in this study, we utilized mouse models to test the hypothesis that dietary carbohydrates modulate energetic, metabolic, and islet adaptions to high-fat diets. To address this, we exposed C57BL/6J mice to 12 wk of 3 eucaloric high-fat diets (>60% calories from fat) with varying total carbohydrate (1-20%) and sucrose (0-20%) content. Our results show that severe restriction of dietary carbohydrates characteristic of ketogenic diets reduces body fat accumulation, enhances energy expenditure, and reduces prevailing glycemia and insulin resistance compared with carbohydrate-rich, high-fat diets. Moreover, severe restriction of dietary carbohydrates also results in functional, morphological, and molecular changes in pancreatic islets highlighted by restricted capacity for β-cell mass expansion and alterations in insulin secretory response. These studies support the hypothesis that low-carbohydrate/high-fat diets provide antiobesogenic benefits and suggest further evaluation of the effects of these diets on β-cell biology in humans.