Beneficial effects of losartan or telmisartan on the local hepatic renin-angiotensin system to counter obesity in an experimental model

摘要

BACKGROUND Obesity has been associated with hepatic overexpression of the renin-angiotensin system(RAS).AIM To evaluate the action of two angiotensin II(ANGII) receptor blockers(losartan or telmisartan) on the modulation of local hepatic RAS and the resulting metabolic effects in a diet-induced obesity murine model.METHODS Twenty C57 BL/6 mice were randomly divided into two nutritional groups for 10 wk: control group(C, n = 5, 10% of energy as fat) or high-fat group(HF, n = 15,50% of energy as fat). After treatment started, the HF group was randomly divided into three groups: untreated HF group(n = 5), HF treated with losartan(HFL, n = 5) and HF treated with telmisartan(HFT, n = 5). The treatments lasted for 5 wk, and the dose was 10 mg/kg body mass.RESULTS HF diet induced body mass gain(+28%, P < 0.0001), insulin resistance(+69%, P =0.0079), high hepatic triacylglycerol(+127%, P = 0.0004), and overexpression of intrahepatic angiotensin-converting enzyme(ACE) 1/ANGII type 1 receptor(AT1 r)(+569.02% and +141.40%, respectively, P < 0.0001). The HFL and HFT groups showed higher ACE2/rMAS gene expression compared to the HF group(ACE2: +465.57%, P = 0.0002 for HFL and +345.17%, P = 0.0049 for HFT; rMAS:+711.39%, P < 0.0001 for HFL and +539.75%, P < 0.0001 for HFT), followed by reduced insulin/glucose ratio(-30% for HFL and-33% for HFT, P = 0.0181),hepatic triacylglycerol levels(-28%, P = 0.0381 for HFL; and-45%, P = 0.0010 for HFT, and Plin2 expression.CONCLUSION Modulation of the intrahepatic RAS, with favored involvement of the ACE2/rMAS axis over the ACE1/AT1 r axis after losartan or telmisartan treatments, caused hepatic and metabolic beneficial effects as demonstrated by reduced hepatic triacylglycerol levels coupled with reduced PLIN 2 expression and improved glycemic control.