Nitrotyrosine and 8-isoprostane formation indicate free radical-mediated injury in hearts of patients subjected to cardioplegia

Tossios, Bloch, Krahwinkel, Mehlhorn (left to right)

NOS-III activity and cGMP content were increased in both cardiac myocytes and endothelial cells at the end of CPB (lower image line) compared with before CPB (upper image line). Nitrotyrosine and 8-isoprostane activity increased mainly in coronary endothelial cells.

At the end of CPB, NOS-III activity, as determined by using television densitometry, was increased compared with that before CPB. Bars represent mean values, with whiskers indicating corresponding SDs (n = 9).

The number of nitrotyrosine-positive capillaries in human myocardium subjected to blood cardioplegia and reperfusion was increased at the end of CPB compared with before CPB, indicating injury induced by peroxynitrite, which was caused by increased NO release. Bars represent mean values, with whiskers indicating corresponding SDs (n = 6).

The number of 8-isoprostane-positive capillaries in human myocardium subjected to blood cardioplegia and reperfusion was increased at the end of CPB compared with before CPB, indicating oxygen-derived free radical-mediated lipid peroxidation. Bars represent mean values, with whiskers indicating corresponding SDs (n = 5).