[The role of apoptosis in hepatic graft rejection]

In 1965, Kerr described a type of death, apoptosis, with different characteristics from necrosis. Apoptosis has an important role in the development and cell homeostasis. Excessive or insufficient apoptosis contributes to the pathogenesis of pathology like ischemia, neurodegeneration, autoimmunity, viral infection, and tumor growth or regression. Apoptosis is subdivided into four sequential phases: order of death; death of cell; phagocytosis of apoptotic bodies and degradation of apoptotic bodies. Death programs converge on sequential activation of a proteases family, caspases. Some aspects of graft rejection can be interpreted as failure of apoptosis in host immunity cells; sometimes rejection involves induction of apoptosis. Apoptotic-type lesions were found in early vascular occlusions, one of the cause of graft failure. Then, an augmented apoptosis in hepatic graft biopsy can be used like a signal of early vascular occlusion. In hepatic transplantation, apoptosis is followed by a proteolytic cascade, which causes sequential activation of caspases. Synthetic inhibitor of caspases can be used, then, in the prevention and/or treatment of pathologies with implication of apoptosis due to ischemia-reperfusion. These inhibitors are not enough for prevention of hepatic lesions, even if caspases inhibitor can be a strategy for treatment of hepatic graft rejection.