ANGIOTENSIN-II RECEPTOR BLOCKADE IN SYRIAN-HAMSTER (T0-2) CARDIOMYOPATHY DOES NOT AFFECT MICROSCOPIC CARDIAC MATERIAL PROPERTIES - IMPLICATIONS FOR MECHANISMS OF TISSUE REMODELING

This study delineates the role of angiotensin II type I (AT(1)) recept or in the remodeling of Syrian cardiomyopathic hamsters. Twelve cardio myopathic (T0-2) hamsters received L-158,809 treatment ad Libitum in t heir drinking water (27 mu g/ml) and 9 cardiomyopathic and 9 normal F1 -B hamsters received tap water from 1 to 4 months of age. Although pha rmacologically effective with regard to complete suppression of the bl ood pressure response to angiotensin II infusion, L-158,809 did not di minish the progression or severity of cardiomyopathy. Heart weight/100 g body weight and left ventricular wall thickness adjusted for body w eight of both L-158,809 and cardiomyopathic control hamsters did not d iffer and exceeded those of F1-B controls (p < 0.05). Myocardial mater ial properties (e.g., stiffness and density) of cardiomyopathic hamste rs treated with L-158,809 were not affected. Thus, the progression of fibrosis, calcification, and necrosis in T0-2 cardiomyopathic hamsters was not sensitive to AT(1) receptor blockade.