AIMTo investigate the relation among myocardial angiotension II receptor (AT1/AT2) expression, calpain and cardiac function in patients with congestive heart failure (CHF).

METHODSMessage RNA (mRNA) expression of AT1/AT2 receptor in myocardial tissue of 39 patients with CHF due to valvular heart disease and 8 control subjects were analyzed using reverse transcriptase-polymerase chain reaction (RT-PCR). Immunoprecipitation was used to assay the protein expression of u-calpain and m-calpain.

RESULTSPathological changes of myocardial tissue in CHF due to valvular heart disease showed typical myocardial remodeling. AT1 receptor mRNA expression was slightly increased in the patients with mild CHF than in the control subjects, but decreased in the moderate and severe CHF patients. No difference was observed in AT2 receptor mRNA expression among all the groups, but the ratio of AT1/AT2 decreased. The protein expression of u-calpain and m-calpain were positively correlated to the levels of cardiac function in patient with CHD.

CONCLUSIONThe expression of AT1 receptor is down-regulated in moderate and severe CHF, the dominant receptor subtype is transformed to AT2. Cardiomyocyte apoptosis or death may be induced via AT2 receptor to activate calpain system, leading the deterioration of cardiac function.