Elevated levels of oxidative DNA damage in serum and myocardium of patients with heart failure

Background: Oxidative stress has been implicated in the pathogenesis of chronic heart failure. The present study investigated whether the levels of 8-hydroxy-2-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, were elevated in the serum and myocardium of patients with dilated cardiomyopathy (DCM), and furthermore whether carvedilol, a vasodilating β-blocker with antioxidant activity, could reduce the levels. Methods and Results: Serum levels of 8-OHdG were measured by enzyme immunoassay in 56 patients with DCM and in 20 control subjects. DCM patients had significantly elevated serum levels of 8-OHdG compared with control subjects. Endomyocardial biopsy samples obtained from 12 DCM patients and 5 control subjects with normal cardiac function were studied immunohistochemically for the expression of 8-OHdG. Positive 8-OHdG staining was found in the nuclei of cardiomyocytes from DCM patients but not in those from control subjects. After treatment with carvedilol, the serum levels of 8-OHdG in DCM patients significantly decreased by 19%, together with amelioration of heart failure. Conclusions: Levels of 8-OHdG are elevated in the serum and myocardium of patients with heart failure. Treatment with carvedilol might be effective for decreasing the oxidative DNA damage.