Agrobiotechnology — animal biotechnol- ogy in agriculture and biomedicine Lecture L17.1 Xenotransplantation — state of art and future

In the near future, transgenic animals with modified immunological systems will become “living tissue and organ banks” used for human transplantation. Xenotransplantation is transplantation of an organ or tissue to a member of a different species. In the context of humans, this term means transplantation of an organ or tissue from the donor animal. In the United States alone, each year the number of patients waiting for kidney, liver or heart transplantation runs into tens of thousands. Only a small percentage can undergo life-saving operations due to the shortage of organs. They are mainly taken from victims of traffic accidents, only those who (or whose families) opted to donate their organs in advance. The limited number of suitable organs is further diminished by the fact that not all organs can be transplanted due to the immunological incompatibility of donor and recipient waiting for transplantation; organs are taken too late — retrieval and transplantation must be performed in the shortest time possible; often minor mistakes in the retrieval and transportation of an organ, which is obtained in a high stress situation, make it unsuitable for transplantation. The same holds true for Poland and other European countries. Creation of animal lines, the potential donors of organs for humans who need their abnormally functioning organs to be replaced, would be a significant breakthrough. Clinical findings indicate that the domestic pig and not, as previously thought, the most closely related nonhuman primates (monkeys), best fulfils the criteria of organ suitability for xenotransplantation. The size of organs and their physiological capacity is almost identical to those of humans. The choice of pigs as potential donors of organs for xenotransplantation is also favoured by the following facts: pigs are a species of high prolificacy and fertility, fast growing, cheap and easy to keep, and their organs reach their full size and physiological capacity in a relatively short period of time necessary for xenotransplantation; pigs are a species relatively susceptible to genetic modification; finally, pigs as a species are virtually free from diseases that could be transmitted to humans via the transplanted organs. The only threats of considerable seriousness are porcine endogenous retroviruses (PERV’s). Acknowledgements Financial support: grant NR 12003606. L17.2