Growing human, perfectly matching organs inside a pig and then transplanting them into humans is not a new idea - it may revolutionize medicine - but a new discovery may also allow pig tissue to be transplanted directly into humans. The research in the Journal of Leukocyte Biology may lead to filling the short term lack of organs for human transplantation. 

Altering or overexpressing the human programmed death ligand-1 (PD-L1) molecule in the endothelial cells of pig arteries reduced the conditions that lead to rejection, it says. This strongly suggests that successful Xenotransplantation means humans could receive altered porcine organs with fewer complications.

To make the discovery, scientists conducted experiments using two groups of pig vascular endothelial cells. The first group was genetically engineered to express human PD-L1, while the second group was normal. When both sets of cells were exposed to human lymphocytes, lower rejection response occurred in the group with the altered gene, while higher rejection responses were seen in the normal cells.

Study results suggest that human PD-L1 could be used as a novel therapeutic agent to enhance tolerance of xenotransplants and also supports the possibility of using human PD-L1 transgenic pigs as xenotransplant donors. Using this type of genetic engineering technique could potentially overcome current challenges related to successful pig/human transplant rejection.

 "Genetically engineered pigs may someday overcome the severe donor organ shortage, and save human lives," said Qing Ding, Ph.D., co-study author from the Shanghai Institute of Immunology at the Shanghai Jiaotong University School of Medicine in Shanghai, China.