Telmisartan inhibits vascular dysfunction and inflammation via activation of peroxisome proliferator-activated receptor-γ in subtotal nephrectomized rat

摘要

Telmisartan, an angiotensin II type 1 receptor blocker, reportedly exhibits a partial peroxisome proliferator-activated receptor (PPAR)-γ agonistic action. To test whether telmisartan ameliorates vascular injury in the chronic kidney disease model rat through the PPAR-γ pathway, telmisartan (5 mg/kg per day, orally), losartan (5 mg/kg per day, orally) or telmisartan plus PPAR-γ antagonist, GW9662 (1 mg/kg/day, i.p.), was administered for 14 days to subtotal nephrectomized rats (Nx). There was no significant difference in systolic blood pressure or fasting blood glucose values among all groups. Subtotal nephrectomy significantly aggravated the levels of urinary protein excretion, blood urea nitrogen and plasma malondialdehyde concentration, which were attenuated by telmisartan or losartan treatment. Vasodilation in response to acetylcholine in the aortic ring was impaired in the Nx, and improved by treatment with telmisartan. Immunohistochemical analysis revealed that the infiltration of adventitial areas by macrophages and expression of osteopontin and vascular cell adhesion molecule-1 were enhanced in the Nx aorta and the overexpression was suppressed by telmisartan. The increased NADPH oxidase-derived superoxide production in the aorta from the Nx rat was suppressed by telmisartan. Cotreatment with GW9662 partly blunted the normalization of vascular dysfunction and inflammation. While losartan also attenuated these vascular changes in the Nx rats, the extent of the attenuation was significantly greater in the telmisartan-treated group than in the losartan-treated group. These results suggest that, in addition to a class effect of angiotensin II type 1 receptor blockers, telmisartan exerted vasoprotective effects through its PPAR-γ agonistic property in rats with renal failure.