Treatment of congestive heart failure - Interfering the aldosterone-cardiac extracellular matrix relationship

Cardiac extracellular matrix undergoes extensive and continuous turnover in volved in the lesion-reparation process, such as in cardiac remodeling, in hypertensive cardiac hypertrophy, in dilated cardiomyopathy, after myocardi al infarction in the transition to heart failure, and during the progressio n of left ventricular dysfunction. Cardiac fibrosis is a major determinant of diastolic dysfunction and pumping capacity, and it may provide the struc tural substrate for arrhythmogenicity, thus potentially contributing the to progression of heart failure and sudden death. Aldosterone was shown to pr omote cardiac fibrosis in various experimental models. It was demonstrated that spironolactone may oppose the effect of aldosterone in promoting cardi ac fibrosis. Measurement of cardiac collagen turnover by use of serological markers is a useful tool for monitoring cardiac tissue repair and fibrosis in experimental models or clinical conditions. We found that high serum le vels of a marker of collagen turnover (procollagen type III N-terminal pept ide) in patients with chronic heart failure receiving conventional therapy, including ACE inhibitors, was associated with high mortality and hospitali zation rates. In RALES (Randomized Aldactone Evaluation Study), in patients randomized to placebo, markers continued to increase or remained unchanged after 6-month follow-up. On the contrary, adding spironolactone 25 mg dail y significantly decreased the levels of these serum markers during the same period. Most importantly, the spironolactone-related morbidity and mortali ty benefit was most predominant in subgroups with highest baseline levels o f serum markers. These results suggest that limitation of the aldosterone-r elated excessive extracellular matrix turnover may be one of the various ex trarenal mechanisms contributing to the beneficial effect of spironolactone in patients with chronic heart failure.