Helaehil, J. V. | bioRxiv Science

bioRxiv2021

Quercetin prevents insulin dysfunction in hypertensive animals

Angiotensin II induced increase in hypertension enhances oxidative stress and compromises insulin action and pancreatic function. Quercetin-rich foods are beneficial for hypertensive and diabetic animals owing to their antioxidant function. The aim of this study was to evaluate the antioxidant effects of quercetin in hypertensive rats on insulin action, signaling, and secretion. Wistar rats were randomly divided into three groups: sham, hypertensive rats (H), and hypertensive rats supplemented with quercetin (HQ). After three months of initial hypertension, quercetin was administered at 50 mg/kg/day for 30 days. Our results indicate that hypertension and serum lipid peroxidation levels were reduced by quercetin supplementation. We observed increased insulin sensitivity in adipose tissue, corroborating the insulin tolerance test, HOMA index, and improvements in lipid profile. Despite normal insulin secretion at 2.8 and 20 mM of glucose, animals treated with quercetin exhibited increased number of islets per section; increased protein expression of muscarinic receptor type 3, VEGF, and catalase in islets; and hepatic mRNA levels of Ide were normalized. In conclusion, supplementation with quercetin improved insulin action and prevented pancreatic and metabolic dysfunction.

physiology↗

bioRxiv2021

Caloric restriction overcomes pre-diabetic and hypertension induced by high fat diet and renal artery stenosis

BackgroundCaloric restriction (CR) is a type of dietary intervention enjoyed as an essential tool in weight loss by modulating critical pathways of metabolic control, although it is not yet clear what repercussions this intervention model results when associated with renovascular hypertension. Here we demonstrate that CR can be beneficial in obese and hypertensive animals. MethodsRats were divided into groups: SHAM, and two groups underwent surgery to clip the left renal artery, to induce renovascular hypertension (OH and OHR). The SHAM diet was performed: 14 weeks normolipidic diet; OH: 2 weeks normolipidic diet + 12 weeks hyperlipidic diet, both ad libitum; OHR: 2 weeks normolipidic diet + 8 weeks ad libitum high fat diet + 4 weeks restricted 40% high fat diet. Resultsthe OHR group dissipated blood pressure, body weight and glucose homeostasis. Reductions in insulinemia, lipids, islets fibrotic areas in the OHR group were observed along with increased insulin sensitivity and normalization of the insulin-degrading enzyme. Nicotinamide phosphoribosyltransferase, insulin receptor, Sirtuin 1 and complex II protein were modulated in liver tissue in the OHR group. Strong correlations, direct or indirect, were evaluated by Spearmans model between SIRT1, AMPK, NAMPT, PGC-1 and NNMT with the reestablishment of blood pressure, weight loss, glycidic and lipid panel and mitochondrial adaptation. ConclusionCR provided short-term beneficial effects to recover physiological parameters induced by a high-fat diet and renal artery stenosis in obese and hypertensive animals. These benefits, even in the short term, can bring physiological benefits in the long run.

physiology↗