Application of GAL-KO transgenic pigs in xenotransplantation: problems and prospects for the future

Xenotransplantation (сross-species transplantation) has a great potential to serve the needs for organs, tissues and cells for transplantation. In this review, the applications of genetically modified pigs as the donors of organs and tissues for clinical transplantation are discussed. The hyperacute rejection (HAR) process is shortly described. One of the ways to overcome HAR is the creation of pigs lacking alpha-1,3-galactosyltransferase (alpha-1,3-GalT) epitopes - the major xenoantigene in pig-to-primate organ xenotransplantation. The analysis of the efficiency of targeting the alpha-1,3-galactosyltransferase gene ( GGTA1 ) in porcine cells by using different methods was performed: the targeting efficiency (the number of piglets carrying the knock-out of GGTA1 born alive from the number of the cloned embryos transferred) is differed between laboratories and varied of 0.0 to 5.0 per cent. The different techniques used for the development of transgenic pigs lacking GGTA1 (GAL-KO pigs) are shortly described. The possible applications of organs and tissues of GAL-KO pigs for xenotransplantation are overviewed. The advantages of using of the skin derived from GAL-KO pigs as a potential alternative for a temporary cover of burns comparing to the alloskin and skin derived from the normal (GAL-positive) pigs are shown. Uses of GAL-KO pigs as donors of heart valves are briefly reviewed. The research aims for the future are discussed.