The favorable metabolic effects of telmisartan have been related to its blockade of angiotensin (Ang) II receptor and action as a partial agonist of peroxisome proliferator-activated receptor γ (PPARγ). We designed a comparative study of telmisartan and losartan in ApoE-deficient mice. ApoE-deficient mice were fed a high-fat diet with or without telmisartan (10 mg/kg/day) or losartan (30 mg/kg/day) for 3 months. Treatment with telmisartan or losartan significantly reduced blood pressure, but did not affect serum cholesterol, triglyceride or glucose levels. Both drugs inhibited the development of lipid-rich plaque as assessed by oil red O staining. However, treatment with telmisartan, but not losartan, significantly improved endothelial dysfunction as assessed by the vasodilator response to acetylcholine. To elucidate the molecular mechanisms of the differential response in the improvement of endothelial dysfunction between telmisartan and losartan, we next focused on the expression of various cytokines. As both telmisartan and losartan attenuated interleukin-6 mRNA expression in the aorta, there was a significant change in endothelial nitric oxide synthase (eNOS) mRNA in the aorta. Notably, telmisartan, but not losartan, significantly increased the expression of hepatocyte growth factor (HGF), but not that of vascular endothelial growth factor (VEGF) in the aorta. Although a decrease in body weight and adipose tissue weight was observed with both telmisartan and losartan, liver weight was significantly decreased in only the telmisartan-treated group. Of importance, telmisartan markedly inhibited lipid accumulation in the liver. Overall, telmisartan and losartan induced differential responses in the improvement of endothelial dysfunction, probably due to their effects on vascular HGF levels and fatty liver. These favorable characteristics of telmisartan might be due to its action as a partial agonist of PPARγ, beyond its blood pressure-lowering effect, through Ang II blockade.

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