Oxidative stress implication in a new ex-vivo cardiac concordant xenotransplantation model.

Xenotransplantation (XT) reveals a growing interest for the treatment of cardiomyopathy. The major barrier is an acute vascular rejection due to an acute humoral rejection. This pathogenesis is a difficult issue and in order to elaborate means for its prevention, we analysed the implication of oxidative stress (OS) on hearts from mini-pigs followed by reperfusion with either autologous or human blood in an attempt to simulate xenotransplantation. About 14 hearts were studied after a Langendorff blood reperfusion: allografts with autologous blood (n = 7) or xenografts with human blood (n = 7). Blood samples were drawn from the coronary sinus to assess ischemia and OS. In xenografts, arrhythmias occurred more frequently (p < 0.01, left ventricular systolic pressure decreased more significantly (p < 0.05), thiobarbituric acid-reactive substances concentrations increased at 30 min (0.7 +/- 0.1 vs. 2.4 +/- 0.3 mmol/l; p < 0.05) while vitamin A levels decreased (p < 0.05). XT was associated with a significant increase in ischemic injury and OS production. OS might play an eminent role in hyperacute humoral rejection.