Role of microcirculation in transplantation

Microcirculatory derangements in organ transplantation, characterized by ca pillary perfusion Failure and inflammation-associated leukocyte recruitment , are major determinants for the manifestation of graft dysfunction and des truction. Although preservation/cold storage, posttransplant reperfusion, a nd rejection have to bet considered as individual factors that contribute t o injury recent studies have. indicated that ischemia-reperfusion-associate d events may trigger immune-response-mediated late rejection. There is majo r evidence that the mircocirculatory derangements induced by cold preservat ion and reperfusion involve oxygen radicals, complement, phospholipase A(2) , leukotrienes, thromboxane, platelet-activating factor, and endothelin-1 a s well as the activation and function of leukocytic and endothelial selecti ns, beta(2)-integrins, and ICAM-1. This view is based on the fact that bloc kade or neutralization of these inflammatory mediators and adhesion molecul es results in significant amelioration of microvascular graft dysfunction. In parallel, rejection-mediated microcirculatory derangements may not only be ameliorated by immunosuppressive agents, such as cyclosporin, deoxysperg ualin, or RS61443, but may in addition, effectively be inhibited by counter acting oxygen radicals, complement, platelet-activating factor anti adhesio n molecules. The introduction of novel techniques for the study of the micr ocirculation in men, such as thermodiffusion and orthogonal polarization sp ectral imaging, may in the future assist in improving both early diagnosis of microcirculatory derangements anti monitoring of appropriateness of ther apy in clinical transplantation surgery. Microcirculation (2000) 7, 291-306 .