Adenosine triphosphate (ATP)-sensitive potassium (KATP) channels in pancreatic β-cells play a crucial role in insulin secretion and glucose homeostasis. These channels are composed of two subunits: a pore-forming subunit (Kir6.2) and a regulatory subunit (sulphonylurea receptor-1). Recent studies identified large number of gain of function mutations in the regulatory subunit of the channel which cause neonatal diabetes. Majority of mutations cause neonatal diabetes alone, however some lead to a severe form of neonatal diabetes with associated neurological complications. This review focuses on the functional effects of these mutations as well as the implications for treatment.
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Obesity is a state of chronic low-grade systemic inflammation. This chronic inflammation is deeply involved in insulin resistance, which is the underlying condition of type 2 diabetes and metabolic syndrome. A significant advance in our understanding of obesity-associated inflammation and insulin resistance has been recognition of the critical role of adipose tissue macrophages (ATMs). Chemokines are small proteins that direct the trafficking of immune cells to sites of inflammation. In addition, chemokines activate the production and secretion of inflammatory cytokines through specific G protein-coupled receptors. ATM accumulation through C-C motif chemokine receptor 2 and its ligand monocyte chemoattractant protein-1 is considered pivotal in the development of insulin resistance. However, chemokine systems appear to exhibit a high degree of functional redundancy. Currently, more than 50 chemokines and 18 chemokine receptors exhibiting various physiological and pathological properties have been discovered. Therefore, additional, unidentified chemokine/chemokine receptor pathways that may play significant roles in ATM recruitment and insulin sensitivity remain to be fully identified. This review focuses on some of the latest findings on chemokine systems linking obesity to inflammation and subsequent development of insulin resistance.
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The aim of this study was an
3T3-L1 preadipocytes differentiated in the presence of varying concentrations of glucose (25, 45, 65, 85, and 105 mM) were assessed for adipogenesis using AdipoRed (Lonza) assay. Cell viability and proliferation were measured using MTT reduction and [3H] thymidine incorporation assay. The extent of glucose uptake and glycogen synthesis were measured using radiolabelled 2-deoxy-D-[1-3H] glucose and [14C]-UDP-glucose. The gene level expression was evaluated using reverse transcription-polymerase chain reaction and protein expression was studied using Western blot analysis.
Glucose at 105 mM concentration was observed to inhibit adipogenesis through inhibition of CCAAT-enhancer-binding proteins, sterol regulatory element-binding protein, peroxisome proliferator-activated receptor and adiponectin. High concentration of glucose induced stress by increasing levels of toll-like receptor 4, nuclear factor κB and tumor necrosis factor α thereby generating activated preadipocytes. These cells entered the state of hyperplasia through inhibition of p27 and proliferation was found to increase through activation of protein kinase B via phosphoinositide 3 kinase dependent pathway. This condition inhibited insulin signaling through decrease in insulin receptor β. Although the glucose transporter 4 (GLUT4) protein remained unaltered with the glycogen synthesis inhibited, the cells were found to exhibit an increase in glucose uptake via GLUT1.
Adipogenesis in the presence of 105 mM glucose leads to an uncontrolled proliferation of activated preadipocytes providing an insight towards understanding obesity.
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A1chieve® was a noninterventional study evaluating the clinical safety and efficacy of biphasic insulin aspart 30, insulin detemir, and insulin aspart.
Korean type 2 diabetes patients who have not been treated with the study insulin or have started it within 4 weeks before enrollment were eligible for the study. The patient selection and the choice of regimen were at the discretion of the physician. The safety and efficacy information was collected from the subjects at baseline, week 12, and week 24. The number of serious adverse drug reactions (SADRs) was the primary endpoint. The changes of clinical diabetic markers at week 12 and/or at week 24 compared to baseline were the secondary endpoints.
Out of 4,058 exposed patients, 3,003 completed the study. During the study period, three SADRs were reported in three patients (0.1%). No major hypoglycemic episodes were observed and the rate of minor hypoglycemic episodes marginally decreased during 24 weeks (from 2.77 to 2.42 events per patient-year). The overall quality of life score improved (from 66.7±15.9 to 72.5±13.5) while the mean body weight was slightly increased (0.6±3.0 kg). The 24-week reductions in glycated hemoglobin, fasting plasma glucose and postprandial plasma glucose were 1.6%±2.2%, 2.5±4.7 mmol/L, and 4.0±6.4 mmol/L, respectively.
The studied regimens showed improvements in glycemic control with low incidence of SADRs, including no incidence of major hypoglycemic episodes in Korean patients with type 2 diabetes.
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To evaluate the effects of severe hypoglycemia without hypokalemia on the electrocardiogram in patients with type 2 diabetes in real-life conditions.
Electrocardiograms of adult type 2 diabetic patients during the episodes of severe hypoglycemia and the recovered stage were obtained and analysed between October 1, 2011 and May 31, 2012. Patients who maintained the normal serum sodium and potassium levels during the episodes of severe hypoglycemia were only selected as the subjects of this study. Severe hypoglycemia was defined, in this study, as the condition requiring active medical assistance such as administering carbohydrate when serum glucose level was less than 60 mg/dL.
Nine type 2 diabetes patients (seven men, two women) were included in the study. The mean subject age was 73.2±7.7 years. The mean hemoglobin A1c level was 6.07%±1.19%. The median duration of diabetes was 10 years (range, 3.5 to 30 years). Corrected QT (QTc) intervals were significantly increased during the episodes of severe hypoglycemia compared to the recovered stage (447.6±18.2 ms vs. 417.2±30.6 ms;
In this study, QTc interval prolongation during the episodes of severe hypoglycemia was observed without hypokalemia. Therefore, the distinct alterations in cardiac repolarization during the episodes of severe hypoglycemia may not be associated with hypokalemia.
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The increasing prevalence of type 2 diabetes mellitus (T2DM) is associated with the rapid spread of obesity. Obesity induces insulin resistance, resulting in β-cell dysfunction and thus T2DM. Green tea extract (GTE) has been known to prevent obesity and T2DM, but this effect is still being debated. Our previous results suggested that circulating green tea gallated catechins (GCs) hinders postprandial blood glucose lowering, regardless of reducing glucose and cholesterol absorption when GCs are present in the intestinal lumen. This study aimed to compare the effect of GTE with that of GTE coadministered with poly-γ-glutamic acid (γ-PGA), which is likely to inhibit the intestinal absorption of GCs.
The
In nondiabetic mice, none of the drugs showed any effects after 4 weeks. In
These results suggest that GTE+γ-PGA treatment than GTE or γ-PGA alone may be a useful tool for preventing both obesity and obesity-induced T2DM.
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Beyond statin therapy for reducing low density lipoprotein cholesterol (LDL-C), additional therapeutic strategies are required to achieve more optimal reduction in cardiovascular risk among diabetic patients with dyslipidemia. To evaluate the effects and the safety of combined treatment with omega-3 fatty acids and statin in dyslipidemic patients with type 2 diabetes, we conducted a randomized, open-label study in Korea. Patients with persistent hypertriglyceridemia (≥200 mg/dL) while taking statin for at least 6 weeks were eligible. Fifty-one patients were randomized to receive either omega-3 fatty acid 4, 2 g, or no drug for 8 weeks while continuing statin therapy. After 8 weeks of treatment, the mean percentage change of low density lipoprotein (LDL) particle size and triglyceride (TG) level was greater in patients who were prescribed 4 g of omega-3 fatty acid with statin than in patients receiving statin monotherapy (2.8%±3.1% vs. 2.3%±3.6%,
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