scholarly journals Baicalein Protects against Type 2 Diabetes via Promoting Isletβ-Cell Function in Obese Diabetic Mice

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Yu Fu ◽  
Jing Luo ◽  
Zhenquan Jia ◽  
Wei Zhen ◽  
Kequan Zhou ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Insulin Secretion ◽  
Glucose Tolerance ◽  
High Fat Diet ◽  
Cell Function ◽  
Diabetic Mice ◽  
Obese Mice ◽  
High Fat ◽  
Middle Aged

In both type 1 (T1D) and type 2 diabetes (T2D), the deterioration of glycemic control over time is primarily caused by an inadequate mass and progressive dysfunction ofβ-cell, leading to the impaired insulin secretion. Here, we show that dietary supplementation of baicalein, a flavone isolated from the roots of Chinese herbScutellaria baicalensis, improved glucose tolerance and enhanced glucose-stimulated insulin secretion (GSIS) in high-fat diet (HFD-) induced middle-aged obese mice. Baicalein had no effect on food intake, body weight gain, circulating lipid profile, and insulin sensitivity in obese mice. Using another mouse model of type 2 diabetes generated by high-fat diet (HFD) feeding and low doses of streptozotocin injection, we found that baicalein treatment significantly improved hyperglycemia, glucose tolerance, and blood insulin levels in these middle-aged obese diabetic mice, which are associated with the improved isletβ-cell survival and mass. In thein vitrostudies, baicalein significantly augmented GSIS and promoted viability of insulin-secreting cells and human islets cultured either in the basal medium or under chronic hyperlipidemic condition. These results demonstrate that baicalein may be a naturally occurring antidiabetic agent by directly modulating pancreaticβ-cell function.

scholarly journals Tetrahydrocurcumin Upregulates the Adiponectin-AdipoR Pathway and Improves Insulin Signaling and Pancreatic β-Cell Function in High-Fat Diet/Streptozotocin-Induced Diabetic Obese Mice

Nutrients ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 4552
Author(s):  
Yi-Zhen Tsai ◽  
Mei-Ling Tsai ◽  
Li-Yin Hsu ◽  
Chi-Tang Ho ◽  
Ching-Shu Lai
Keyword(s):  
Type 2 Diabetes ◽  
Insulin Signaling ◽  
High Fat Diet ◽  
Cell Function ◽  
Obese Mice ◽  
High Fat ◽  
Islet Mass ◽  
Beneficial Effects ◽  
Β Cell Function

Impairment of adiponectin production and function is closely associated with insulin resistance and type 2 diabetes, which are linked to obesity. Studies in animal models have documented the anti-diabetic effects of tetrahydrocurcumin (THC). Although several possible mechanisms have been proposed, the contribution of adiponectin signaling on THC-mediated antihyperglycemic effects remains unknown. Here, we report that adiposity, steatosis, and hyperglycemia were potently attenuated in high-fat diet/streptozotocin-induced diabetic obese mice after they received 20 and 100 mg/kg THC for 14 weeks. THC upregulated UCP-1 in adipose tissue and elevated adiponectin levels in the circulation. THC upregulated the AdipoR1/R2-APPL1-mediated pathway in the liver and skeletal muscle, which contributes to improved insulin signaling, glucose utilization, and lipid metabolism. Furthermore, THC treatment significantly (p < 0.05) preserved islet mass, reduced apoptosis, and restored defective insulin expression in the pancreatic β-cells of diabetic obese mice, which was accompanied by an elevation of AdipoR1 and APPL1. These results demonstrated a potential mechanism underlying the beneficial effects of THC against hyperglycemia via the adiponectin-AdipoR pathway, and thus, may lead to a novel therapeutic use for type 2 diabetes.

scholarly journals Polyphenol-Rich Fraction of Brown AlgaEcklonia cavaCollected from Gijang, Korea, Reduces Obesity and Glucose Levels in High-Fat Diet-Induced Obese Mice

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Eun Young Park ◽  
Eung Hwi Kim ◽  
Mi Hwi Kim ◽  
Young Wan Seo ◽  
Jung Im Lee ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Body Weight ◽  
Glucose Tolerance ◽  
Mrna Expression ◽  
Inflammatory Cytokines ◽  
High Fat Diet ◽  
Obese Mice ◽  
High Fat ◽  
Glucose Levels

Ecklonia cava (E. cava)is a brown alga that has beneficial effects in models of type 1 and type 2 diabetes. However, the effects ofE. cavaextracts on diet-induced obesity and type 2 diabetes have not been specifically examined. We investigated the effects ofE. cavaon body weight, fat content, and hyperglycemia in high-fat diet- (HFD) induced obese mice and sought the mechanisms involved. C57BL/6 male mice were fed a HFD (60% fat) diet or normal chow. After 3 weeks, the HFD diet group was given extracts (200 mg/kg) ofE. cavaharvested from Jeju (CA) or Gijang (G-CA), Korea or PBS by oral intubation for 8 weeks. Body weights were measured weekly. Blood glucose and glucose tolerance were measured at 7 weeks, and fat pad content and mRNA expression of adipogenic genes and inflammatory cytokines were measured after 8 weeks of treatment. G-CA was effective in reducing body weight gain, body fat, and hyperglycemia and improving glucose tolerance as compared with PBS-HFD mice. The mRNA expression of adipogenic genes was increased, and mRNA expression of inflammatory cytokines and macrophage marker gene was decreased in G-CA-treated obese mice. We suggest that G-CA reduces obesity and glucose levels by anti-inflammatory actions and improvement of lipid metabolism.

scholarly journals The Antiinflammatory Cytokine Interleukin-1 Receptor Antagonist Protects from High-Fat Diet-Induced Hyperglycemia

Endocrinology ◽  
2008 ◽  
Vol 149 (5) ◽  
pp. 2208-2218 ◽  
Author(s):  
Nadine S. Sauter ◽  
Fabienne T. Schulthess ◽  
Ryan Galasso ◽  
Lawrence W. Castellani ◽  
Kathrin Maedler
Keyword(s):  
Type 2 Diabetes ◽  
Insulin Secretion ◽  
Receptor Antagonist ◽  
High Fat Diet ◽  
Cell Function ◽  
Interleukin 1 ◽  
High Fat ◽  
Β Cell

Subclinical inflammation is a recently discovered phenomenon in type 2 diabetes. Elevated cytokines impair β-cell function and survival. A recent clinical trial shows that blocking IL-1β signaling by IL-1 receptor antagonist (IL-1Ra) improves β-cell secretory function in patients with type 2 diabetes. In the present study, we provide further mechanisms of the protective role of IL-1Ra on the β-cell. IL-1Ra prevented diabetes in vivo in C57BL/6J mice fed a high-fat/high-sucrose diet (HFD) for 12 wk; it improved glucose tolerance and insulin secretion. High-fat diet treatment increased serum levels of free fatty acids and of the adipokines resistin and leptin, which were reduced by IL-1Ra treatment. In addition, IL-1Ra counteracted adiponectin levels, which were decreased by high-fat feeding. Studies on isolated islets revealed that IL-1Ra specifically acted on the β-cell. IL-1Ra protected islets from HFD treated animals from β-cell apoptosis, induced β-cell proliferation, and improved glucose-stimulated insulin secretion. Insulin mRNA was reduced in islets from mice fed a HFD but normalized in the IL-1Ra group. Our results show that IL-1Ra improves β-cell survival and function, and support the potential role for IL-1Ra in the treatment of diabetes.

scholarly journals Exercise Affects Blood Glucose Levels and Tissue Chromium Distribution in High-Fat Diet-Fed C57BL6 Mice

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1658 ◽  
Author(s):  
Geng-Ruei Chang ◽  
Po-Hsun Hou ◽  
Wen-Kai Chen ◽  
Chien-Teng Lin ◽  
Hsiao-Pei Tsai ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
High Fat Diet ◽  
Cell Function ◽  
Body Weight Gain ◽  
Liver Fat ◽  
Standard Diet ◽  
Model Assessment ◽  
Obese Mice ◽  
High Fat

Obesity is commonly associated with hyperglycemia and type 2 diabetes and negatively affects chromium accumulation in tissues. Exercise prevents and controls obesity and type 2 diabetes. However, little information is available regarding chromium changes for regulating glucose homeostasis in high-fat diet (HFD)-fed animals/humans who exercise. Therefore, this study explored the effects of exercise and whether it alters chromium distribution in obese mice. Male C57BL6/J mice aged 4 weeks were randomly divided into two groups and fed either an HFD or standard diet (SD). Each group was subgrouped into two additional groups in which one subgroup was exposed to treadmill exercise for 12 weeks and the other comprised control mice. HFD-fed mice that exercised exhibited significant lower body weight gain, food/energy intake, daily food efficiency, and serum leptin and insulin levels than did HFD-fed control mice. Moreover, exercise reduced fasting glucose and enhanced insulin sensitivity and pancreatic β-cell function, as determined by homeostasis model assessment (HOMA)-insulin resistance and HOMA-β indices, respectively. Exercise also resulted in markedly higher chromium levels within the muscle, liver, fat tissues, and kidney but lower chromium levels in the bone and bloodstream in obese mice than in control mice. However, these changes were not noteworthy in SD-fed mice that exercised. Thus, exercise prevents and controls HFD-induced obesity and may modulate chromium distribution in insulin target tissues.

scholarly journals Dual Mechanism for Type-2 Diabetes Resolution after Roux-en-Y Gastric Bypass

2009 ◽  
Vol 75 (6) ◽  
pp. 498-503 ◽  
Author(s):  
Edward Lin ◽  
S. Scott Davis ◽  
Jahnavi Srinivasan ◽  
John F. Sweeney ◽  
Thomas R. Ziegler ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Weight Loss ◽  
Gastric Bypass ◽  
Insulin Secretion ◽  
Glucose Tolerance ◽  
Cell Function ◽  
Β Cell ◽  
Peripheral Insulin Resistance

Resolution of Type-2 diabetes mellitus (DM) after weight loss surgery is well documented, but the mechanism is elusive. We evaluated the glucose-insulin metabolism of patients undergoing a Roux-en-Y gastric bypass (RYGB) using the intravenous glucose tolerance test (IVGTT) and compared it with patients who underwent laparoscopic adjustable gastric band (AB) placement. Thirty-one female patients (age range, 20 to 50 years; body mass index, 47.2 kg/m2) underwent RYGB. Nine female patients underwent AB placement and served as control subjects. All patients underwent IVGTT at baseline and 1 month and 6 months after surgery. Thirteen patients undergoing RYGB and one patient undergoing AB exhibited impaired glucose tolerance or DM defined by the American Diabetes Association. By 6 months post surgery, diabetes was resolved in all but one patient undergoing RYGB but not in the patient undergoing AB. Patients with diabetes undergoing RYGB demonstrated increased insulin secretion and β-cell responsiveness 1 month after surgery and continued this trend up to 6 months, whereas none of the patients undergoing AB had changes in β-cell function. Both patients undergoing RYGB and those undergoing AB demonstrated significant weight loss (34.6 and 35.0 kg/m2, respectively) and improved insulin sensitivity at 6 months. RYGB ameliorates DM resolution in two phases: 1) early augmentation of beta cell function at 1 month; and 2) attenuation of peripheral insulin resistance at 6 months. Patients undergoing AB only exhibited reduction in peripheral insulin resistance at 6 months but no changes in insulin secretion.

Immediate enhancement of first-phase insulin secretion and unchanged glucose effectiveness in patients with type 2 diabetes after Roux-en-Y gastric bypass

2015 ◽  
Vol 308 (6) ◽  
pp. E535-E544 ◽  
Author(s):  
Christoffer Martinussen ◽  
Kirstine N. Bojsen-Møller ◽  
Carsten Dirksen ◽  
Siv H. Jacobsen ◽  
Nils B. Jørgensen ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Insulin Secretion ◽  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
Cell Function ◽  
Β Cell ◽  
Glucose Effectiveness ◽  
Β Cell Function ◽  
First Phase Insulin Secretion

Roux-en-Y gastric bypass surgery (RYGB) in patients with type 2 diabetes often leads to early disease remission, and it is unknown to what extent this involves improved pancreatic β-cell function per se and/or enhanced insulin- and non-insulin-mediated glucose disposal (glucose effectiveness). We studied 30 obese patients, including 10 with type 2 diabetes, 8 with impaired glucose tolerance, and 12 with normal glucose tolerance before, 1 wk, and 3 mo after RYGB, using an intravenous glucose tolerance test (IVGTT) to estimate first-phase insulin response, insulin sensitivity (Si), and glucose effectiveness with Bergman's minimal model. In the fasting state, insulin sensitivity was estimated by HOMA-S and β-cell function by HOMA-β. Moreover, mixed-meal tests and oral GTTs were performed. In patients with type 2 diabetes, glucose levels normalized after RYGB, first-phase insulin secretion in response to iv glucose increased twofold, and HOMA-β already improved 1 wk postoperatively, with further enhancements at 3 mo. Insulin sensitivity increased in the liver (HOMA-S) at 1 wk and at 3 mo in peripheral tissues (Si), whereas glucose effectiveness did not improve significantly. During oral testing, GLP-1 responses and insulin secretion increased regardless of glucose tolerance. Therefore, in addition to increased insulin sensitivity and exaggerated postprandial GLP-1 levels, diabetes remission after RYGB involves early improvement of pancreatic β-cell function per se, reflected in enhanced first-phase insulin secretion to iv glucose and increased HOMA-β. A major role for improved glucose effectiveness after RYGB was not supported by this study.

scholarly journals The long non-coding RNA Pax6os1/PAX6-AS1 modulates pancreatic β-cell identity and function

2020 ◽  
Author(s):  
Livia Lopez-Noriega ◽  
Rebecca Callingham ◽  
Aida Martinez-Sánchez ◽  
Grazia Pizza ◽  
Nejc Haberman ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Insulin Secretion ◽  
Pancreatic Islets ◽  
Glucose Homeostasis ◽  
High Glucose ◽  
High Fat Diet ◽  
High Fat ◽  
Β Cell ◽  
And Function

AbstractLong non-coding RNAs (lncRNAs) are emerging as crucial regulators of β-cell development and function. Consequently, the mis-expression of members of this group may contribute to the risk of type 2 diabetes (T2D). Here, we investigate roles for an antisense lncRNA expressed from the Pax6 locus (annotated as Pax6os1 in mice and PAX6-AS1 in humans) in β-cell function. The transcription factor Pax6 is required for the development of pancreatic islets and maintenance of a fully differentiated β-cell phenotype. Pax6os1/PAX6-AS1 expression was increased in pancreatic islets and β-cell lines at high glucose concentrations, in islets from mice fed a high fat diet, and in those from patients with type 2 diabetes. Silencing or deletion of Pax6os1/PAX6-AS1 in MIN6 cells and EndoC-βH1cells, respectively, upregulated β-cell signature genes, including insulin. Moreover, shRNA-mediated silencing of PAX6-AS1 in human islets not only increased insulin mRNA, but also enhanced glucose-stimulated insulin secretion and calcium dynamics. In contrast, inactivation of Pax6os1 in mice was largely without effect on glucose homeostasis, though female Pax6os1 null mice on high fat diet (HFD) showed a tendency towards enhanced glucose clearance. Together, our results suggest that increased expression of PAX6-AS1 at high glucose levels may contribute to β-cell dedifferentiation and failure in some forms of type 2 diabetes. Thus, targeting PAX6-AS1 may provide a promising strategy to enhance insulin secretion and improve glucose homeostasis in type 2 diabetes.

scholarly journals Circulating Retinol Binding Protein 4 is Inversely Associated with Pancreatic β Cell Function across the Spectrum of Glycemia

2020 ◽  
Author(s):  
Rong Huang ◽  
Songping Yin ◽  
Yongxin Ye ◽  
Nixuan Chen ◽  
Shiyun Luo ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Insulin Secretion ◽  
Glucose Tolerance ◽  
Cell Function ◽  
Retinol Binding Protein ◽  
Β Cell ◽  
Retinol Binding Protein 4 ◽  
Β Cell Function ◽  
Oral Minimal Model

<p>OBJECTIVE: The aim of this study was to examine the association of circulating retinol binding protein 4 (RBP4) levels with β cell function across the spectrum of glucose tolerance from normal to overt type 2 diabetes. RESEARCH DESIGN AND METHODS: A total of 291 subjects aged 35-60 with normal glucose tolerance (NGT), newly diagnosed impaired fasting glucose or glucose tolerance (IFG/IGT) and type 2 diabetes were screened by standard 2-h oral glucose tolerance test (2-h OGTT) with the use of traditional measures to evaluate β cell function. 74 subjects from these participants were recruited in oral minimal model test and assessed β cell function with model-derived indices. Circulating RBP4 levels were measured by a commercially available ELISA kit. RESULTS: Circulating RBP4 levels were significantly and inversely correlated with β cell function indicated by the Stumvoll first-phase and second-phase insulin secretion indexes, but not with HOMA-β, calculated from the 2-h OGTT in 291 subjects across the spectrum of glycemia. The inverse association was also observed in subjects involved in the oral minimal model test with β cell function assessed by both direct measures and model-derived measures, after adjustment for potential confounders. Moreover, RBP4 emerged as an independent factor of the disposition index-total insulin secretion (DI-PhiT). CONCLUSION: Circulating RBP4 levels are inversely and independently correlated with β cell function across the spectrum of glycemia, providing another possible explanation of the linkage between RBP4 and the pathogenesis of type 2 diabetes.</p>

Sign in / Sign up

Export Citation Format

Share Document