Endocrine cells of the pancreatic islet interact with their microenvironment to maintain tissue homeostasis. Communication with local macrophages is particularly important in this context, but the homeostatic functions of human islet macrophages are not known. Here we show that the human islet contains macrophages in perivascular regions that are the main local source of the anti-inflammatory cytokine

Swi-independent 3a and 3b (Sin3a and Sin3b) are paralogous transcriptional coregulators that direct cellular differentiation, survival, and function. Here, we report that mouse Sin3a and Sin3b are co-produced in most pancreatic cells during embryogenesis but become much more enriched in endocrine cells in adults, implying continued essential roles in mature endocrine-cell function. Mice with loss of

HLA-DQA1 and -DQB1 are strongly associated with type 1 diabetes (T1D), and DQ8.1 and DQ2.5 are major risk haplotypes. Next generation targeted sequencing of HLA-DQA1 and -DQB1 in Swedish newly diagnosed 1-18 year-old patients (n=962) and controls (n=636) was used to construct abbreviated DQ haplotypes, converted into amino acid (AA) residues, and assessed for their associations with T1D. A hierarchically-organized

NADPH facilitates glucose-stimulated insulin secretion (GSIS) in pancreatic islet (PI) β-cells by an as yet unknown mechanism. We found NADPH oxidase, isoform-4 (NOX4), to be the major producer of cytosolic H2O2, essential for GSIS, while the increase in ATP/ADP alone was insufficient. The fast GSIS phase was absent in PIs from NOX4-null, β-cell-specific knockout mice (NOX4βKO) (not NOX2KO), and NOX4-silenced

Sodium glucose co-transporter-2 inhibitors (SGLT2i) have favorable cardiovascular outcomes in diabetic patients. However, whether SGLT2i can improve obesity-related cardiac dysfunction is unknown. Sestrin2 is a novel stress-inducible protein that regulates AMPK-mTOR and suppresses oxidative damage. The aim of this study was to determine whether empagliflozin (EMPA) improves obesity-related cardiac

Lipid droplets (LDs) are frequently increased when excessive lipid accumulation leads to cellular dysfunction. Distinct from mouse beta cells, LDs are prominent in human beta cells, however, the regulation of LD mobilization (lipolysis) in human beta cells remains unclear. We found that glucose increases lipolysis in non-diabetic human islets, but not in type 2 diabetic (T2D) islets, indicating dysregulation

Hypo-vascularised diabetic non-healing wounds are due to reduced number and impaired physiology of endogenous endothelial progenitor cell (EPC) population that, limits their recruitment and mobilization at the wound site. To enrich the EPC repertoire from non-endothelial precursors, abundantly available mesenchymal stromal cells (MSCs) were reprogrammed into induced-endothelial cells (iECs). We identified

Obesity is a risk factor for type 2 diabetes (T2D), however not all obese individuals develop the disease. In this study, we aimed to investigate the cause of differential insulin secretion capacity of pancreatic islets from T2D and non-T2D (ND) especially obese donors (BMI ≥30 kg/m2). Islets from obese T2D donors had reduced insulin secretion, decreased β-cell exocytosis and higher expression of fatty

Hyperglycemia is a potent regulator of endogenous glucose production (EGP). Loss of this ‘glucose effectiveness’ is a major contributor to elevated plasma glucose concentrations in type 2 diabetes (T2D). ATP-sensitive potassium channels (KATP channels) in the central nervous system (CNS) have been shown to regulate EGP in humans and rodents. We examined the contribution of central KATP channels to

The purpose of this study was to investigate the protective role of Peroxisome Proliferator-Activated Receptor-alpha (PPARα) against diabetic keratopathy and corneal neuropathy. Corneal samples were obtained from diabetic and non-diabetic human donors. Streptozotocin-induced diabetic rats and mice were orally treated with PPARα agonist fenofibrate. As shown by immunohistochemistry and Western blotting

The pancreatic islet is a highly-vascularized endocrine micro-organ. The unique architecture of rodent islets, a so-called core-mantle arrangement seen in 2D images, led researchers to seek functional implications for islet hormone secretion. Three models of islet blood flow were previously proposed, all based on the assumption that islet microcirculation occurs in an enclosed structure. Recent electrophysiological

By Max Bingham, PhD

In type 2 diabetes, β-cells endure various forms of cellular stress, including oxidative stress and endoplasmic reticulum stress, secondary to increased demand for insulin production and extracellular perturbations, including hyperglycemia. Chronic exposure to stress causes impaired insulin secretion, apoptosis, and loss of cell identity, and a combination of these processes leads to β-cell failure

Diabetes is now a pandemic disease. Moreover, a large number of people with prediabetes are at risk for developing frank diabetes worldwide. Both type 1 and type 2 diabetes increase the risk of atherosclerotic cardiovascular disease (CVD). Even with statin treatment to lower LDL cholesterol, patients with diabetes have a high residual CVD risk. Factors mediating the residual risk are incompletely characterized

Hepatic steatosis, the excess storage of intrahepatic lipids, is a rampant clinical problem associated with the obesity epidemic. Hepatic steatosis is linked to increased risk for insulin resistance, type 2 diabetes, and cardiovascular and advanced liver disease. Accumulating evidence shows that physical activity, exercise, and aerobic capacity have profound effects on regulating intrahepatic lipids

Hepatosteatosis, which is frequently associated with development of metabolic syndrome and insulin resistance, manifests when triglyceride (TG) input in the liver is greater than TG output, resulting in the excess accumulation of TG. Dysregulation of lipogenesis therefore has the potential to increase lipid accumulation in the liver, leading to insulin resistance and type 2 diabetes. Recently, efforts

Glucagon is historically described as the counterregulatory hormone to insulin, induced by fasting/hypoglycemia to raise blood glucose through action mediated in the liver. However, it is becoming clear that the biology of glucagon is much more complex and extends beyond hepatic actions to exert control on glucose metabolism. We discuss the inconsistencies with the canonical view that glucagon is primarily

Glucagon and its partner insulin are dually linked in both their secretion from islet cells and their action in the liver. Glucagon signaling increases hepatic glucose output, and hyperglucagonemia is partly responsible for the hyperglycemia in diabetes, making glucagon an attractive target for therapeutic intervention. Interrupting glucagon signaling lowers blood glucose but also results in hyperglucagonemia

Secretion of glucagon from the pancreatic alpha cells is conventionally seen as the first and most important defense against hypoglycemia. Recent findings, however, show that alpha cell signals stimulate insulin secretion from the neighboring beta cell. This perspective focuses on these seemingly counterintuitive local actions of alpha cells and describes how they impact islet biology and glucose metabolism

Genetic studies of patients with neonatal progeroid syndrome led to the discovery of the novel fasting-induced, glucogenic, and orexigenic hormone named asprosin, the C-terminal cleavage product of profibrillin. Upon secretion, asprosin travels to the liver, where it exerts a glucogenic effect through OR4M1, an olfactory G-protein–coupled receptor. It also crosses the blood-brain barrier to stimulate

Reduced storage of dietary fatty acids (DFA) in abdominal adipose tissues with their enhanced cardiac partitioning has been shown in subjects with type 2 diabetes (T2D) and pre-diabetes. We measured DFA metabolism and organ partitioning using positron-emission-tomography with oral and i.v.long-chain fatty acid and glucose tracers during a standard liquid meal in 12 obese subjects with T2D prior to

A single bout of exercise enhances insulin action in the exercised muscle. However, not all human studies find that this translates into increased whole-body insulin action, suggesting that insulin action in rested muscle or other organs may be decreased by exercise. To investigate this, eight healthy men underwent a euglycemic hyperinsulinemic clamp on two separate days: One day with prior one-legged

Excessive fructose consumption is closely linked to the pathogenesis of metabolic disease. Carbohydrate response element-binding protein (ChREBP) is a transcription factor essential for fructose tolerance in mice. However, the functional significance of liver ChREBP in fructose metabolism remains unclear. Here, we show that liver ChREBP protects mice against fructose-induced hepatotoxicity by regulating

Insulin-mediated microvascular recruitment (IMVR) regulates delivery of insulin and glucose to insulin-sensitive tissues. We have previously proposed that perivascular adipose tissue (PVAT) controls vascular function through outside-to-inside communication and through vessel-to-vessel, or "vasocrine" signaling. However, direct experimental evidence supporting a role of local PVAT in regulating IMVR

Glucagon-like peptide 1 (GLP-1) mimetics are effective drugs for treatment of type 2 diabetes, and there is consequently extensive interest in increasing endogenous GLP-1 secretion and L-cell abundance. Here we identify G-protein-coupled bile acid receptor 1 (GPBAR1) as a selective regulator of intestinal L-cell differentiation. Lithocholic acid and the synthetic GPBAR1 agonist, L3740, selectively

Around 10% of type 2 diabetes patients suffer from latent autoimmune diabetes in adults (LADA). This study provides a systematic assessment of the pathology of the endocrine pancreas of patients with LADA and for comparison in a first rat model miming the characteristics of LADA patients. Islets in human and rat pancreases were analyzed by immunohistochemistry for immune cell infiltrate composition

Host environment is a crucial factor for considering the transplant of stem cell-derived immature pancreatic cells in patients with type 1 diabetes. Here, we investigated the effect of insulin-deficient diabetes on the fate of immature pancreatic endocrine cell grafts and the underlying mechanisms. Human induced pluripotent stem cell-derived pancreatic endocrine progenitor cells (EPCs), which contained

Aging-dependent changes in tissue function are associated with the development of metabolic diseases. However, the molecular connections linking aging, obesity and diabetes remain unclear. Lamin A, lamin C and progerin, products of the Lmna gene, have antagonistic functions on energy metabolism and lifespan. Lamin C, albeit promoting obesity, increases lifespan suggesting that this isoform is crucial

Autoimmunity against pancreatic β-cell autoantigens is a characteristic of childhood type 1 diabetes. Autoimmunity usually appears in genetically susceptible children with the development of autoantibodies against (pro)insulin in early childhood. The offspring of mothers with type 1 diabetes are protected from this process. The aim of this study was to determine whether the protection conferred by

The signal peptide of preproinsulin is a major source for HLA class I autoantigen epitopes implicated in CTL-mediated beta-cell destruction in Type 1 Diabetes (T1D). Among them, the 10-mer epitope located at the C-terminal end of the signal peptide was found to be the most prevalent in recent onset T1D patients. While the combined action of signal peptide peptidase and endoplasmic reticulum aminopeptidase

SGLT2 inhibitors lower plasma glucose but stimulate endogenous glucose production. The aim of the present study was to examine the effect of dapagliflozin on EGP while clamping plasma glucose, insulin and glucagon concentrations at their fasting level. 38 T2DM patients received an 8-hour measurement of EGP (3H-glucose) on 3 occasions. After a 3-hour tracer equilibration, subjects received: (i) dapagliflozin

Type 2 diabetes accounts for 90% of diabetic population, and these patients are generally obese and hyperlipidemic. In addition to hyperglycemia, hyperlipidemia is also closely related with diabetic retinopathy. Aim was to investigate retinopathy in a model closely mimicking the normal progression and metabolic features of type 2 diabetic population, and elucidate the molecular mechanism. Retinopathy

Current therapeutic strategies for diabetic foot ulcer (DFU) have focused on developing topical healing agents, but few agents have controlled prospective data to support their effectiveness in promoting wound healing. We tested a stem cell mobilizing therapy for DFU using a combination of AMD3100 and low-dose FK506 (Tacrolimus) (AF) in streptozocin-induced type 1 diabetic (T1DM) rats and type 2 diabetic

Clinical studies have suggested that changes in peripheral nerve microcirculation may contribute to nerve damage in diabetic polyneuropathy (DN). It has recently been shown that high-sensitivity Troponin assays (hsTNT) provide predictive values for both cardiac and peripheral microangiopathy in type 2 diabetes (T2D). The aim of this study was to investigate the association of sciatic nerve structural

Diabetic retinopathy (DR) is a widespread vision-threatening disease, and neuroretinal abnormality should be considered as an important problem. Brain-derived neurotrophic factor (BDNF) has recently been considered as a possible treatment to prevent DR-induced neuroretinal damage but how BDNF is upregulated in DR remains unclear. We found increase in hydrogen peroxide (H2O2) in the vitreous of patients

Diabetic retinopathy is the most common microvascular complication of diabetes, characterized by the formation of fibrovascular membranes that consist of a variety of cells including vascular endothelial cells (ECs). New therapeutic approaches for this diabetic complication are urgently needed. Here, we report that in cultured human retinal microvascular (HRECs) high glucose induced expression of p110δ

Schwann cell-derived exosomes communicate with dorsal root ganglia (DRG) neurons. The present study investigated the therapeutic effect of exosomes derived from healthy Schwann cells (SC-Exos) on diabetic peripheral neuropathy (DPN). We found that intravenous administration of SC-Exos to type II diabetic db/db mice with peripheral neuropathy remarkably ameliorated DPN by improving sciatic nerve conduction

Long-term hyperglycemia in diabetic patients leads to human serum albumin (HSA) glycation, which may impair HSA function as a transport protein and affect the therapeutic efficacy of anticoagulants in diabetic patients. In this study, a novel mass spectrometry (MS) approach was developed to reveal the differences in the profiles of HSA glycation sites between diabetic and healthy subjects. K199 was

The cardiovascular benefits of fibrates have been shown to be heterogeneous and to depend on the presence of atherogenic dyslipidemia. We investigated whether genetic variability in the PPARA gene, coding for the pharmacological target of fibrates (PPAR-alpha), could be used to improve the selection of patients with type 2 diabetes who may derive cardiovascular benefit from addition of this treatment

Most replicated genetic determinants for type 1 diabetes are common (minor allele frequency [MAF] > 5%). We aimed to identify novel rare or low-frequency (MAF < 5%) single nucleotide polymorphisms (SNPs) with large effects on risk of type 1 diabetes. We undertook deep imputation of genotyped data followed by genome-wide association testing and meta-analysis of 9,358 type 1 diabetes cases and 15,705

American Diabetes Association “Standards of Medical Care in Diabetes” is based on a complete review of the relevant literature by a diverse group of highly trained clinicians and researchers. After weighing the quality of evidence, from rigorous double-blind clinical trials to expert opinion, recommendations are drafted, reviewed, and submitted for approval to the American Diabetes Association Executive

Branched chain amino acids (BCAAs) are associated with the progression of obesity-related metabolic disorders, including T2DM and non-alcoholic fatty liver disease. However, whether BCAAs disrupt the homeostasis of hepatic glucose and lipid metabolism remains unknown. In this study, we observed that BCAAs supplementation significantly reduced high-fat (HF) diet-induced hepatic lipid accumulation while

Conceivably, upregulation of myo -inositol oxygenase (MIOX) is associated with altered cellular redox. Its promoter includes oxidant-response elements, and we also discovered binding sites for XBP-1, a transcription factor of ER stress response. Previous studies indicate that MIOX’s upregulation in acute tubular injury is mediated by oxidant and ER stress. Here, we investigated if hyperglycemia leads

As an alternative to lifelong insulin supplementation, potentiation of immune tolerance in type 1 diabetes patients could prevent the autoimmune destruction of pancreatic islet beta cells. This study was aimed to assess whether the G3c monoclonal antibody (mAb), which triggers the glucocorticoid-induced TNFR-related (Gitr) co-stimulatory receptor, promotes the expansion of regulatory T cells (Tregs)

Amylin, a pancreatic hormone and neuropeptide, acts principally in the hindbrain to decrease food intake and has been recently shown to act as a neurotrophic factor to control the development of AP→NTS and ARC→PVN axonal fiber outgrowth. Amylin is also able to activate ERK signaling specifically in POMC neurons independently of leptin. To investigate the physiological role of amylin signaling in POMC

Despite considerable progress, development of glucose-responsive insulins (GRI) still largely depends on empirical knowledge and tedious experimentation – especially on rodents. To assist the rational design and clinical translation of the therapeutic, we present a Pharmacokinetic Algorithm Mapping GRI Efficacies in Rodents and Humans (PAMERAH), built upon our previous human model. PAMERAH constitutes

Progression from the initial vascular response upon hyperglycemia to a proliferative stage with neovacularizations is the hallmark of proliferative diabetic retinopathy. Here we report on the novel diabetic pdx1 -/- zebrafish mutant as model for diabetic retinopathy that lacks the transcription factor pdx1 via CRISPR/Cas9-mediated gene knockout leading to disturbed pancreatic development and hyperglycemia

Diabetic keratopathy occurs in approximately 70% of all diabetics. This study was designed to examine the effects of vitamin D receptor knockout (VDR-/-) and vitamin D deficiency (VDD) on corneal epithelial wound healing and nerve density in diabetic mice. Diabetes was induced using the low dose streptozotocin method. Corneal epithelial wounds were created using an Alger brush and wound healing was

Approximately 40% of patients with diabetic macular edema (DME) are resistant to anti-vascular endothelial growth factor (VEGF) therapy (rDME). Here, we demonstrate that significant correlations between inflammatory cytokines and VEGF, as observed in naive DME, are lost in patients with rDME. VEGF overexpression in the mouse retina caused delayed inflammatory cytokine upregulation, monocyte/macrophage

Abnormal interactions between misfolded mutant and wild-type (WT) proinsulin in the endoplasmic reticulum (ER) drive the molecular pathogenesis of Mutant- INS -gene induced Diabetes of Youth (MIDY). How these abnormal interactions are initiated remains unknown. Normally, proinsulin-WT dimerizes in the ER. Here, we suggest that the normal proinsulin-proinsulin contact surface, involving the B-chain

MG53 is a member of the TRIM protein family that is predominantly expressed in striated muscles and participates in cell membrane repair. Controversy exists regarding MG53’s role in insulin signaling and manifestation of diabetes. We generated db/db mice with either whole-body ablation or sustained elevation of MG53 in the bloodstream in order to evaluate the physiological function of MG53 in diabetes

We investigated whether a polymorphism in codons 22 and 23 of the glucocorticoid (GC) receptor gene [GAGAGG(GluArg) --> GAAAAG(GluLys)] is associated with altered GC sensitivity, anthropometric parameters, cardiovascular risk factors, and sex steroid hormones. In a subgroup of 202 healthy elderly subjects of the Rotterdam Study, we identified 18 heterozygotes (8.9%) for the 22/23EK allele (ER22/23EK

The incidence of type 2 diabetes (T2D) has rapidly increased over recent decades, and T2D has become a leading public health challenge in China. Compared with European descents, Chinese patients with T2D are diagnosed at a relatively young age and low BMI. A better understanding of the factors contributing to the diabetes epidemic is crucial for determining future prevention and intervention programs

Glucagon-like peptide 1 (GLP-1) is a potent incretin hormone produced in the L-cells of the distal ileum and colon. In the L-cells, GLP-1 is generated by tissue-specific posttranslational processing of the proglucagon gene (1). Nutrients, including glucose, fatty acids, and dietary fiber, are all known to upregulate the transcription of the gene encoding GLP-1, and they can stimulate the release of

An ageing global population combined with sedentary lifestyles and unhealthy diets has contributed to an increasing incidence of obesity and type 2 diabetes. These metabolic disorders are associated with perturbations to nitric oxide (NO) signaling and impaired glucose metabolism. Dietary inorganic nitrate, found in high concentration in green leafy vegetables, can be converted to NO in vivo and demonstrates

Vitamin D deficiency has been associated with increased incidence of diabetes, both in humans and animal models. In addition, association between vitamin D receptor (VDR) gene polymorphisms and diabetes has also been described. However, the involvement of VDR in the development of diabetes, specifically in pancreatic β-cell, has not been elucidated yet. Here we aimed to study the role of VDR in β-cell

Inadequate insulin secretion in response to glucose is an important factor for β-cell failure in type 2 diabetes (T2D). Although HMG-CoA reductase degradation 1 (HRD1), a subunit of the endoplasmic reticulum-associated degradation (ERAD) complex, plays a pivotal role in β-cell function, HRD1 elevation in a diabetic setting contributes to β-cell dysfunction. We report herein the excessive HRD1 expression