Hydroxypropylated Tapioca Starch Retards the Development of Insulin Resistance in KKAy Mice, a Type 2 Diabetes Model, Fed a High-Fat Diet

2009 ◽  
Vol 74 (7) ◽  
pp. H232-H236 ◽  
Author(s):  
Makoto Tachibe ◽  
Ryo Kato ◽  
Shozo Sugano ◽  
Taro Kishida ◽  
Kiyoshi Ebihara
2016 ◽  
Vol 310 (8) ◽  
pp. E643-E651 ◽  
Author(s):  
Kei-ichi Ozaki ◽  
Midori Awazu ◽  
Mayuko Tamiya ◽  
Yuka Iwasaki ◽  
Aya Harada ◽  
...  

Extracellular signal-regulated kinase (ERK) has been implicated in the development of insulin resistance associated with obesity and type 2 diabetes mellitus. We have now examined the potential of pharmacological targeting of the ERK pathway with MEK (ERK kinase) inhibitors (PD184352 and PD0325901) for the treatment of obesity-associated insulin resistance. The effects of PD184352 and PD0325901 on the expression of adipocytokines and lipolysis activity were thus examined in 3T3-L1 adipocytes maintained in long-term culture as a model of adipocyte hypertrophy. Leptin receptor-deficient ( db/db) mice and high-fat diet-fed KKAy mice, both of which are models of type 2 diabetes, were also treated orally with PD184352 to examine its effects on the diabetic condition. ERK activity was increased in hypertrophic 3T3-L1 adipocytes as well as in adipose tissue of db/db mice and high-fat diet-fed KKAy mice, and this enhanced ERK signaling was associated with dysregulation of adipocytokine expression and increased lipolysis activity. Specific blockade of the ERK pathway in hypertrophic 3T3-L1 adipocytes by MEK inhibitors ameliorated the dysregulation of adipocytokine expression and suppressed the enhanced lipolysis activity. Furthermore, repeated oral administration of PD184352 normalized hyperglycemia and hyperlipidemia and improved insulin sensitivity and glucose tolerance in the diabetic mice. These results suggest that sustained activation of the ERK pathway in adipocytes is associated with the pathogenesis of type 2 diabetes and that selective blockade of this pathway with MEK inhibitors warrants further study as a promising approach to the treatment of insulin resistance and type 2 diabetes.


Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Varunkumar G Pandey ◽  
Lars Bellner ◽  
Victor Garcia ◽  
Joseph Schragenheim ◽  
Andrew Cohen ◽  
...  

20-HETE (20-Hydroxyeicosatetraenoic acid) is a cytochrome P450 ω-hydroxylase metabolite of arachidonic acid that promotes endothelial dysfunction, microvascular remodeling and hypertension. Previous studies have shown that urinary 20-HETE levels correlate with BMI and plasma insulin levels. However, there is no direct evidence for the role of 20-HETE in the regulation of glucose metabolism, obesity and type 2 diabetes mellitus. In this study we examined the effect of 20-SOLA (2,5,8,11,14,17-hexaoxanonadecan-19-yl-20-hydroxyeicosa-6(Z),15(Z)-dienoate), a water-soluble 20-HETE antagonist, on blood pressure, weight gain and blood glucose in Cyp4a14 knockout (Cyp4a14-/-) mice fed high-fat diet (HFD). The Cyp4a14-/- male mice exhibit high vascular 20-HETE levels and display 20-HETE-dependent hypertension. There was no difference in weight gain and fasting blood glucose between Cyp4a14-/- and wild type (WT) on regular chow. When subjected to HFD for 15 weeks, a significant increase in weight was observed in Cyp4a14-/- as compared to WT mice (56.5±3.45 vs. 30.2±0.7g, p<0.05). Administration of 20-SOLA (10mg/kg/day in drinking water) significantly attenuated the weight gain (28.7±1.47g, p<0.05) and normalized blood pressure in Cyp4a14-/- mice on HFD (116±0.3 vs. 172.7±4.6mmHg, p<0.05). HFD fed Cyp4a14-/- mice exhibited hyperglycemia as opposed to normal glucose levels in WT on a HFD (154±1.9 vs. 96.3±3.0 mg/dL, p<0.05). 20-SOLA prevented the HFD-induced hyperglycemia in Cyp4a14-/- mice (91±8mg/dL, p<0.05). Plasma insulin levels were markedly high in Cyp4a14-/- mice vs. WT on HFD (2.66±0.7 vs. 0.58±0.18ng/mL, p<0.05); corrected by the treatment with 20-SOLA (0.69±0.09 ng/mL, p<0.05). Importantly, glucose and insulin tolerance tests showed impaired glucose homeostasis and insulin resistance in Cyp4a14-/- mice on HFD; ameliorated by treatment with 20-SOLA. This novel finding that blockade of 20-HETE actions by 20-SOLA prevents HFD-induced obesity and restores glucose homeostasis in Cyp4a14-/- mice suggests that 20-HETE contributes to obesity, hyperglycemia and insulin resistance in HFD induced metabolic disorder. The molecular mechanisms underlying 20-HETE mediated metabolic dysfunction are being currently explored.


2020 ◽  
Vol 295 (31) ◽  
pp. 10842-10856 ◽  
Author(s):  
Wen Liu ◽  
Ye Yin ◽  
Meijing Wang ◽  
Ting Fan ◽  
Yuyu Zhu ◽  
...  

Chronic low-grade inflammation plays an important role in the pathogenesis of type 2 diabetes. Src homology 2 domain-containing tyrosine phosphatase-2 (SHP2) has been reported to play diverse roles in different tissues during the development of metabolic disorders. We previously reported that SHP2 inhibition in macrophages results in increased cytokine production. Here, we investigated the association between SHP2 inhibition in macrophages and the development of metabolic diseases. Unexpectedly, we found that mice with a conditional SHP2 knockout in macrophages (cSHP2-KO) have ameliorated metabolic disorders. cSHP2-KO mice fed a high-fat diet (HFD) gained less body weight and exhibited decreased hepatic steatosis, as well as improved glucose intolerance and insulin sensitivity, compared with HFD-fed WT littermates. Further experiments revealed that SHP2 deficiency leads to hyperactivation of caspase-1 and subsequent elevation of interleukin 18 (IL-18) levels, both in vivo and in vitro. Of note, IL-18 neutralization and caspase-1 knockout reversed the amelioration of hepatic steatosis and insulin resistance observed in the cSHP2-KO mice. Administration of two specific SHP2 inhibitors, SHP099 and Phps1, improved HFD-induced hepatic steatosis and insulin resistance. Our findings provide detailed insights into the role of macrophagic SHP2 in metabolic disorders. We conclude that pharmacological inhibition of SHP2 may represent a therapeutic strategy for the management of type 2 diabetes.


2020 ◽  
Vol Volume 13 ◽  
pp. 2279-2288
Author(s):  
Heqing Huang ◽  
Ling Luo ◽  
Zhitao Liu ◽  
Yan Li ◽  
Zhaochen Tong ◽  
...  

2021 ◽  
Vol 10 (3) ◽  
pp. 331-338
Author(s):  
Pratibha Nadig ◽  
Meharban Asanaliyar ◽  
Kevin Manohar Salis

Introduction: The principal mechanism responsible for reducing blood glucose is through insulin-stimulated glucose transport into skeletal muscle. The transporter protein that mediates this uptake is GLUT-4. A defect in this step is associated with reduced glucose utilization in muscle and adipose tissue, as observed in insulin-resistant type-2 diabetes mellitus (T2DM) patients. This study aimed to develop an experimental T2DM model and evaluate altered glucose transporter type 4 (GLUT-4) levels as a biomarker of insulin resistance. Antidiabetic activities of Syzygium cumini hydro-ethanolic seed extracts (SCE) were also evaluated. Methods: Adult male Wistar albino rats were fed a high-fat diet for 12 weeks and dosed intraperitoneally with streptozotocin (35 mg/kg). After treatment for 21 days, all investigations were done. The homeostasis model of assessment (HOMA) was used for the calculation of insulin resistance (HOMA-IR) and beta-cell function (HOMA-B) index. Diaphragm muscle and retroperitoneal fat were collected for real-time polymerase chain reaction (RT-PCR) studies. Results: A significant increase in fasting blood glucose, HOMA-IR, and serum lipids, and a decrease in serum insulin and HOMA-B were observed in the diabetic group, effects that reversed following pioglitazone and SCE treatment. The diabetic group showed a downregulation of GLUT-4 expression in skeletal muscle while an increase was observed in adipose tissue. Conclusion: A high-fat diet and low dose streptozotocin-induced experimental T2DM model of insulin resistance was developed to screen novel insulin sensitizers. Data generated demonstrated that altered GLUT-4 levels could be used as a biomarker of insulin resistance. Antidiabetic activity of S. cumini hydro-ethanolic seed extract was also confirmed in this study.


2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Banumathi K. Cole ◽  
Margaret A. Morris ◽  
Wojciech J. Grzesik ◽  
Kendall A. Leone ◽  
Jerry L. Nadler

Type 2 diabetes is associated with obesity, insulin resistance, and inflammation in adipose tissue. 12/15-Lipoxygenase (12/15-LO) generates proinflammatory lipid mediators, which induce inflammation in adipose tissue. Therefore we investigated the role of 12/15-LO activity in mouse white adipose tissue in promoting obesity-induced local and systemic inflammatory consequences. We generated a mouse model for fat-specific deletion of 12/15-LO,aP2-Cre;12/15-LOloxP/loxP, which we call ad-12/15-LO mice, and placed wild-type controls and ad-12/15-LO mice on a high-fat diet for 16 weeks and examined obesity-induced inflammation and insulin resistance. High-fat diet-fed ad-12/15-LO exhibited improved fasting glucose levels and glucose metabolism, and epididymal adipose tissue from these mice exhibited reduced inflammation and macrophage infiltration compared to wild-type mice. Furthermore, fat-specific deletion of 12/15-LO led to decreased peripheral pancreatic islet inflammation with enlarged pancreatic islets when mice were fed the high-fat diet compared to wild-type mice. These results suggest an interesting crosstalk between 12/15-LO expression in adipose tissue and inflammation in pancreatic islets. Therefore, deletion of 12/15-LO in adipose tissue can offer local and systemic protection from obesity-induced consequences, and blocking 12/15-LO activity in adipose tissue may be a novel therapeutic target in the treatment of type 2 diabetes.


2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A446-A446
Author(s):  
Austin Reilly ◽  
Hongxia Ren

Abstract Insulin signaling lowers postprandial glucose by stimulating cell surface translocation of the insulin sensitive glucose transporter 4 (GLUT4). In order to better understand how insulin resistance contributes to the pathophysiological progression of type 2 diabetes, we generated human GLUT4 promoter-driven insulin receptor knockout (GIRKO) mice and characterized their metabolic features relative to control mice. Although the role of insulin resistance in diabetes is beyond dispute, our previous studies showed that GIRKO mice fed normal chow diet (NCD) had an unexpectedly low rate of frank diabetes despite severe insulin resistance in muscle, fat, and brain. In the current study, we first sought to determine whether GIRKO mice would respond to high-fat diet (HFD) challenge with worsened glycemic outcome compared to control mice on HFD. Secondly, we sought to determine whether HFD-induced pathologies in GIRKO mice were caused by adaptations in the gastrointestinal (GI) tract and microbiome. We discovered that after beginning the HFD-feeding regimen, GIRKO mice rapidly developed hyperinsulinemia and hyperglycemia without excessive adiposity gain. Furthermore, GIRKO mice displayed dyslipidemia via increased hepatic lipid accumulation and serum lipid content. We used indirect calorimetry to characterize the metabolic features of single-housed mice. HFD-fed GIRKO mice had comparatively lower respiratory exchange ratio (RER), indicating relatively greater lipid metabolism compared to control mice on HFD. Despite having increased circulating incretins, GIRKO mice had impaired oral glucose tolerance and limited glucose-lowering benefit from Exendin-4 (Ex-4) injections. Since HFD promotes inflammation in the gastrointestinal (GI) tract, we performed gene expression analysis and pathway analysis of duodenal mRNAs to investigate whether inflammatory response, glucose transport, and lipid transport were altered in HFD-fed GIRKO mice. Among the top pathways discovered in pathway analysis were those involved with inflammatory signaling, carbohydrate transport, and xenobiotic metabolism, which supports that HFD-fed GIRKO mice have increased GI tract inflammation which may promote impaired glucose homeostasis. In conclusion, our studies suggest that HFD increased intestinal inflammation and exacerbated insulin resistance, which catalyzed the pathological progression of diabetes. Future studies are necessary to identify the molecular and cellular signaling pathways which culminate in frank diabetes, which may lead to therapeutic targets for regulating glucose homeostasis in the context of insulin resistance.


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