Organ transplantation and its physiological implications – A review

Organ transplantation is the mechanism of transferring an organ (heart, lung, etc.) from one body to another or from one donor site on the patient’s own body for the purpose of replacing the recipient’s damaged or absent organ. The different types of transplantation considering the relationship between the donor and the recipient species are autotransplantation, xenotransplantation, iso-transplantation and allotransplantation. Allotransplantation is further divided into split and damino-transplant. Donors for organ transplantation are classified into living and deceased donors. Living donors remain alive and donate renewable or regenerative organs. Deceased or cadaveric donors are thosethat are cardiac dead or brain dead. Some of the organs that can be transplanted include intestine, eyes, thymus, heart, kidney, liver, and lung, out of which the last four are done worldwide. The transplantation of organs, mainly of allotransplantation and xenotransplantation types is accompanied by graft rejection. Other implications of organ transplantation include: immune system inefficiency, transplant rejection, chimerism andxenozoonosis. Graft rejection can be solved using immunosuppressive mechanism aided by immunosuppressant drugs. Immusuppression is also limited by some side effects and immune system inefficiency. Some of the strategies for overcoming rejection include the interruption of the complement cascade, use of transgeneic organs and induction of nonresponsive haematopoietic-chimerism.Keywords: Organ transplantation, Transgeneic organs, Allotransplantation, Autotransplantation, Xenotransplantation, Isotransplantation, Allografts, Haematopoietic-chimeris