Aldosterone synthase (CYP11B2) expression and myocardial fibrosis in the failing human heart

The pathway of tissue aldosterone production may exist in the heart, and may be an important contributory factor to myocardial fibrosis and cardiac remodelling in the failing heart. CYP11B2 (aldosterone synthase) catalyses the final step of aldosterone production. The aim of the present study was to determine whether CYP11B2 and CYP11B1 (11β-hydroxylase) are expressed in myocardial tissues, and whether these enzymes contribute to collagen accumulation and myocardial dysfunction in the failing human heart. Endomyocardial tissues were obtained from 23 patients with chronic heart failure (CHF) and 10 controls. CYP11B2 and CYP11B1 mRNA levels were measured by real-time quantitative reverse transcriptase-PCR. The myocardial collagen volume fraction (CVF) was determined by digital planimetry. CYP11B2 mRNA expression was greater in the CHF group than in the controls ( P r = 0.64, P = 0.001). CYP11B2 mRNA was particularly highly expressed in subgroups of CHF patients with a large left ventricular end-systolic diameter (>55mm) or a low left ventricular ejection fraction (