S. Korea engineers pig for organ transplants

South Korean scientists have created a genetically modified pig that has a better chance of success in animal-to-human organ transplants, a state institute said Wednesday. The new pig, named Somang-i, is designed to produce an antigen (the human lymphocyte differentiation antigen, cluster of differentiation 73 or CD 73) that will help prevent hyperacute rejection of animal organs by human bodies, according to the Rural Development Administration (RDA), a research arm of the Ministry of Food, Agriculture, Forestry and Fisheries. The human body will reject a foreign organ transplant generally in stages: hyperacute, acute, cell-mediated and chronic. "The value of Somang-i is especially high in that by crossbreeding it with (our other genetically modified pigs) Xeno or Mideumi we can produce new genetically modified pigs with genes that can help prevent a multiple number of causes of human rejection," the RDA said. South Korean scientists developed Xeno, the country's first genetically modified pig, in 2009 by removing the enzyme alpha-1, 3 galactosyltransferase that also causes hyperacute rejection of animal organs in human bodies. A second pig, Mideumi, followed last year with an added gene that causes excessive production of membrane cofactor protein, which helps prevent hyperacute and acute rejections. South Korea currently has about 20 clones of Xeno, and will begin its first test organ transplant from one of the genetically modified pigs to a monkey at the end of this year or early next year, according to Park Jin-ki, director of the animal biotechnology division at the National Institute of Animal Science. "There are still many unknown genes that may cause humans to reject animal organs, but we are now a step closer to animal-to-human transplantation," he said in a press briefing. Organ transplantation from one species to another, called xenotransplantation, is gaining attention globally as the number of patients in need of organ transplants is expected to surpass 1.5 million by 2015.