Protective effect of bisoprolol on beta-1 adrenoceptor peptide-induced autoimmune myocardial damage in rabbits

Idiopathic dilated cardiomyopathy is a severe disease of unknown etiology. Accumulating evidence suggests that agonist-like autoantibodies against the beta 1 adrenoceptor in the circulation of dilated cardiomyopathy may play an important role. The aim of this study was to evaluate the effects of the selective BZ-adrenoceptor blocker, bisoprolol, on beta 1-adrenoceptor pept ide induced autoimmune myocardial damage. In the animal model of autoimmune cardiomyopathy induced by active immuniza tion of rabbits with beta 1-adrenoceptor peptide, bisoprolol was given at a dose of 3 mg/day throughout the study period. Our results showed high tite r of anti-pr adrenoceptor antibody in the immunized group throughout the st udy but not in the group receiving only bisoprolol. Crossreactivity to beta 2 adrenoceptors was observed in some of the immunized rabbits, but disappe ared almost entirely after 6 months. As compared to the beta 1-adrenoceptor peptide immunized group without bisoprolol treatment, bisoprolol treated b eta 1-receptor peptide immunized group showed increase in the wall thicknes s and decreases in cavity dimension in anatomical measurements and only mil d alterations in macro- and microscopic examinations. Thus, our study clearly demonstrated a beneficial effect of bisoprolol in r abbits who have developed autoimmune myocardial damage.