Annexins, calcium-dependent phospholipid binding proteins in irreducible heart failure

To analyze the expression and distribution of annexins V and VI in intact human hearts and in dilated cardiomyopathy (DCM) in patients with irreducible heart failure. The study included nine patients with DCM and irreducible heart failure. By immunoblotting and indirect immunofluorescence, the amount and location of annexins was determined using samples of left ventricular (LV) myocardium collected during orthotopic heart allotransplantation. Samples of LV myocardium from 9 individuals who died of craniocerebral trauma served as controls. Quantitative analysis showed an increased level of both annexins in the myocardium of DCM patients compared with normal myocardium: 122 +/- 5% (p < 0.05) and 119 +/- 5% (p < 0.05) for annexins V and VI, respectively. In the intact heart annexin V was located at the sarcolemma and intercalated discs, while in the myocardium with heart failure mainly in the interstitium. In normal hearts, annexin VI was located at the sarcolema, including T-tubules, Z-lines and intercalated discs. In heart failure, annexin V1 was also located in the interstitium. Redistribution of annexins V and VI in the cardiomyocytes in the interstitial space may have important functional consequences and indicates the role of myocardial protein expression disturbances in the etiology and/or pathogenesis of heart failure in pa-