Spironolactone improves carotid artery fibrosis and distensibility in rat post-ischaemic heart failure

Abstract

Myocardial infarction causes neurohormonal activation involving aldosterone and angiotensin II (AngII). These hormones may increase arterial stiffness, an independent cardiovascular risk factor contributing to progression of congestive heart failure (CHF). This study aimed to determine the effect of aldosterone and AngII blockade on carotid artery distensibility and collagen density in adult Wistar rats with MI-induced CHF. Five groups were studied: Sham-operated, CHF, CHF + spironolactone, CHF + lisinopril, CHF + Spironolactone + Lisinopril. After echocardiography, in vitro isobaric carotid distensibility (echo-tracking technique) and collagen density were measured, and the incremental elastic modulus (Einc) calculated. In the CHF group, intra-ventricular pressure and cardiac weight were increased; carotid distensibility was reduced (CHF: 0.42 ± 0.30 per mmHg 3 versus sham: 1.75 ± 0.50 per mmHg 3; P < 0.001), and collagen content increased by 87% when compared to sham. All treatments reduced intra-ventricular pressure, carotid distensibility and fibrosis when compared to CHF but did not change cardiac weight. However, carotid distensibility and intra-ventricular pressure were not completely restored towards sham values and were significantly and inversely related. Spironolactone, which did not decrease significantly blood pressure, was the only drug reducing Einc independently of wall stress (WS). Thus, MI-induced CHF was associated with carotid artery remodeling. This vascular change, which may contribute to maintain cardiac hypertrophy and CHF, is largely prevented by AngII and aldosterone blockade. Only spironolactone reduced the stiffness of carotid wall material independently of blood pressure and WS.