Xenotransplantation is the transplantation of organs from other animal species into humans.It is studied in a variety of conditions, such as replacement of the heart, lungs, liver, and kidneys. It is also used for non–whole organs such as diabetes, neurodegenerative disorders, chronic pain control, and ex vivo perfusion events. Pig organs and tissues are majorly used for research since their biochemical profile is similar to that of human organs. Disadvantages of xenotransplantation includes hyperacute rejection, delayed rejection, and cell-based immune rejection not forgetting novel infections. An argument over the pros and cons of xenotransplantation has been solved through clinical trials in countries like US and UK. Companies have ventured in this since they believe it is significant
The first attempts to use animal organs in humans was in the early 1960s, where chimpanzee kidneys were used. From the result obtained, one patient survived for nine months with normal kidney function before dying from the effects of immunosuppression whereas the other had a rejection episode that was relieved by steroid therapy hence making xenotransplantation successful. Heart, liver, and kidney transplants were attempted but not even one-year survival was achieved rendering xenotransplantation invalid.
Interest in xenotransplantation is geared by promising results and demand of this act as well as academic clinical work, there is considerable corporate interest in the field. There are also several strategic alliances in this field including Bio Transplant and Novartis Pharma heightened two years of xenotransplantation indulgence hence creates transplant tolerance by bone marrow.
Xenotransplantation is a necessary solution to a hard problem, such as irreversible and terminal tissue and organ failure which brings into existence rejection of the organ and cells and the risk of introducing novel infections into the human species. There are three types of xenograft rejection, which changes on the transplant nature i.e an entire organ or a cell. Hyperacute rejection is mediated by preformed and new antibodies invading antigens. Delayed xenograft/acute vascular rejection, has a process which is not understood, but may involve host antibody and immune cell binding to the vascular endothelium of the xenograft, causing destruction. Cellular immune response consists of pathways alike to the rejection pathways of allografts mediated by histocompatibility determinants.
In the resolution of hyperacute rejection, antibodies are used against the Gal carbohydrate epitope revealed on the surface of pig cells. Delayed rejection is targeted against the vascular endothelium of the organ, it involves B cells. Cell-based rejection is powerful in xenotransplants, it involves helper and killer T cells.
Clinicians tried to implant fetal pig islet cells into human diabetic patients although it never worked in reducing insulin requirement as attested by the Swedish scientist. Different studies applied fetal pig neural cells in patients with Huntington’s or Parkinson’s disease, it was still unclear, effect of microencapsulated bovine chromaffin cells on models of monkey Parkinson’s disease resulted in small chances of Parkinsonian symptoms for a period of 9 months. An AIDS patient got baboon bone marrow cells to raise T cell levels but there was no graft survival.
Xenotransplantation is therefore a critical process which is well implemented, will help and improve the health sector as well as many sectors. Although it is a complex method, many scientists has shown interest in developing it.