Fundamental problems of xenotransplantation.
Xenogeneic transplantation of organs will certainly solve the problem of organ shortage if it succeeds in long term function of the xenografts. Accommodation and rejection of the grafts depend however not only on the immunological mechanisms but, as already recognized in chronic rejection i.e. transplant atherosclerosis, in many other biochemical and physiological, even morphological characters including inflammatory events originating from infections. Preformed natural antibodies, an important part of the preimmunitary system turn again out to be a lock with seven seals. With increasing amounts of data the confusion about possibly an epiphenomenom in xenotransplantation becomes complete. Complement developed by nature before immunoglobulins can be activated by many ways--inducing a series of cascades like cell lysis, blood clotting, cell adherence and liberation of oxygen radicals. Large amounts of foreign proteins are released in the circulation when for example xenogeneic livers or other organs suffer from hyper acute rejection. The function of the liberated enzymes, hormones and inhibitors is far from being understood or even investigated. The amount of potassium released from a deteriorating liver is able to mimic a sometimes lethal cardioplegic situation. First data coming from intra vital microscopy herald that adhesion molecules, the newest but not last in line of trouble shooters play together with integrins and interleukins and eicosanoids a major role in microcirculation, be it as falsely activated system or as incompatible system not able to protect from the attack of white blood cells, their adhesion and migration.(ABSTRACT TRUNCATED AT 250 WORDS)
Hammer
C
C
Institute of Surgical Research, University of Munich, Germany.
D000818:Animals; D015815:Cell Adhesion Molecules / Q000502:physiology; D006133:Growth Substances / Q000502:physiology; D006728:Hormones / Q000502:physiology; D006801:Humans; D016377:Organ Transplantation / Q000379:methods*; D014183:Transplantation, Heterologous
D015815:Cell Adhesion Molecules; D006133:Growth Substances; D006728:Hormones