Scientists Pave Way For Pig-to-Human Organ Transplant

Date: 12 August 2017 - 21:14

News ID: ۴۲۷۹۵

WASHINGTON (Dispatches)-Scientists have removed DNA-based viruses that usually infect pig organs, raising the chances that these animal organs could be safely transplanted into human patients one day.
However, the breakthrough, according to authors of the study published in the journal Science, would still need to change other elements of pig transplants to ensure the human body doesn't reject them.
Currently, there is a dramatic shortage in the number of organ transplants available for people who need them and many people die before they receive one. Animals such as pigs could theoretically supply an unlimited source of such organs. But immune incompatibilities and viruses that are incorporated into the pig genome, called porcine endogenous retroviruses (PERVs), have made it very likely that such pig organs would never take on their own.
The team first confirmed that PERVs in pig cells can be transmitted to human cells when cultured together. Exposing human cells infected with PERV to uninfected humans cells also resulted in transmission, highlighting the need to deactivate PERVs in pigs if transplantation is to one day occur.
Next, the researchers mapped and characterized the PERVs present in the genome of pig fibroblast cells, identifying 25 in total. They used the gene editing tool CRISPR to deactivate all 25 genomic sites. Despite the presence of highly modified cells in the population, none of the cloned cells could be grown with greater than 90% PERV editing efficiency. By adding a concoction of additional factors related to DNA repair, however, the team was able to grow viable cells with 100% of PERVs deactivated.
When they implanted the embryos into sows, they found that the resulting piglets exhibited no signs of PERVs, with some piglets surviving up to four months after birth.