The expression of heat shock protein 60 in patients with dilated cardiomyopathy

Objective: Heat shock proteins (hsps) have been shown to be important antig ens in a number of autoimmune diseases. We have previously shown the presen ce of autoantibodies against hsp60 in a high proportion of patients with di lated cardiomyopathy (DCM). This study set out to investigate the expressio n of hsp60 in the myocardium of 30 patients with DCM and a control group of 30 normal donors. Design: The expression of hsp60 was quantitated at the p rotein and mRNA level by Western blotting and RT-PCR, respectively, and its distribution was investigated by immunocytochemistry. Results: Quantitatio n of hsp60 showed a 5-fold increase in the DCM hearts over that in die dono r hearts. By immunocytochemistry 13 patients with DCM showed increased posi tive staining localised to the connective tissue. Semi-quantitative RT-PCR analysis of hsp60 showed a significantly increased amount of hsp60 at the m RNA level in the DCM hearts than in the controls. Conclusions: These result s unequivocally demonstrate a raised level of expression of endogenous hsp6 0 in the myocardium of patients with DCM. The increased expression of hsp60 in the myocardium of patients with DCM may render such cells susceptible t o react with circulating autoantibodies to hsp60 and hsp65 found in a high proportion of patients with this disease.