Connective tissue growth factor induction in a pressure-overloaded heart ameliorated by the angiotensin II type 1 receptor blocker olmesartan

Connective tissue growth factor (CTGF) is a secreted protein that regulates fibrosis. We hypothesized that CTGF is induced in a pressure-overloaded (PO) heart and that blocking the angiotensin II type 1 receptor would reduce CTGF expression. Accordingly, we administered olmesartan and compared its effects with other antihypertensive drugs in a PO heart. CTGF induction was determined in a rat PO model, and olmesartan, hydralazine or saline was continuously administered. The effects of olmesartan on CTGF induction, myocyte hypertrophy and fibrosis were evaluated. The effect of olmesartan on cardiac function was also examined in CTGF- and transforming growth factor-beta 1 (TGF-β1)-infused rats. CTGF was increased in the PO heart 3 days after aortic banding and was markedly distributed around the perivascular fibrotic area. After 28 days, blood pressure was not significantly different in the olmesartan and hydralazine groups, but olmesartan treatment reduced CTGF distribution in PO hearts. Olmesartan was associated with a significantly reduced myocyte hypertrophy index (4.77±0.48 for olmesartan and 6.05±1.45 for saline, P