Activation of Matrix Metalloproteinases Precedes Left Ventricular Remodeling in Hypertensive Heart Failure Rats

Abstract
Background— Matrix metalloproteinases (MMPs) are activated in dilated failing hearts, and angiotensin-converting enzyme (ACE) inhibition prevents left ventricular (LV) dilatation. However, it remains unclear whether activation of MMPs precedes or is secondary to LV remodeling, and an effect of ACE inhibition on MMPs is unknown. Methods and Results— Dahl salt-sensitive rats fed a high-salt diet from 8 weeks served as the hypertensive heart failure (HF) model. LV echo, histological study, measurement of mRNA levels, and gelatin zymography were performed before (at 23 weeks) and after (at 26 weeks) the development of LV dilatation and pulmonary edema. The same procedures were conducted in the HF model rats treated with a subdepressor dose of ACE inhibitor (enalapril 5 mg · kg−1 · d−1) from 9 weeks. Rats fed on normal chow served as age-matched controls. In the untreated HF model rats, gene expression of MMP-2 and MMP-9 and tissue gelatinase activity were elevated at 23 weeks without LV dilatation. LV dilatat...