Increase in G protein-coupled receptor autoantibodies with decline of cardiac function in hypercholesterolemic rats.

OBJECTIVE This study aimed to explore the effects of diet-induced hypercholesterolemia (HC) on the production of G protein-coupled receptor autoantibodies and to elucidate the potential mechanisms involved. MATERIALS AND METHODS Male Wistar rats were fed a normal or high-cholesterol diet for 8 weeks. Cardiac function, autoantibodies against G protein-coupled receptors, the beat frequency of neonatal cardiomyocytes, the CD4+/CD8+ T-lymphocyte ratio and lymph leukocyte counts in the spleen were determined. RESULTS Diet-induced hypercholesterolemia significantly increased the levels of autoantibodies against α1- and β1-adrenergic receptors and the angiotensin II type 1 receptor in sera, as well as the CD4+/CD8+ T-lymphocyte ratio and lymph leukocyte count in the spleen, and decreased cardiac function. There were strong negative correlations between the levels of autoantibodies and cardiac injury. CONCLUSIONS The present study demonstrates, for the first time, that G protein-coupled receptor autoantibodies exist in the sera of hypercholesterolemic rats and that the levels of these autoantibodies are related to cardiac function, which implies that these cardiac receptor autoantibodies may play a role in cardiac dysfunction in hypercholesterolemic rats.