What Gene-Altering for Pigs and Ants Might Mean for Humans

"The chance of transmitting Perv from the pig organ to the human cells was a significant barrier and the study shows yet another application of the Crispr-Cas9 system".

According to the US Health Resources and Services Administration, there are more than 118,000 people in the US who are on the waiting list for organ transplants.

Researchers at Harvard University report in a new study that they have used the CRISPR-Cas9 gene-editing technique to enable pig-to-human organ transplantation without disease transfer, which could help lessen the number of patients who do not receive an organ transplant because of shortages. This breakthrough in producing the first PERV-free pigs is an important milestone for xenotransplantation. "We are pushing the envelope of technology day by day". "I think the risk to society is very low".

The existence of Pervs has been a major stumbling block preventing the development of genetically engineered pigs to provide kidneys and other organs for transplant into human patients.

"We got perfectly healthy piglets", Church tells The Verge, "so that's unbelievable". CRISPR can be toxic to cells because it causes breaks in DNA strands, which can lead cells to self-destruct. The first, Yang told Business Insider in March, is the virology, or the fact that pigs carry genes encoded with viruses that could transmit disease to humans - that's the PERV genes that Egenesis is working to deactivate.

Porcine endogenous retroviruses (Pervs) are permanently embedded in the pig genome but research has shown they can infect human cells, posing a potential hazard.

Another pleasant surprise, Church adds, is that the piglets did not get reinfected with the viruses in the womb. Unfortunately, there are two problems standing in the way. So far the team has only made female pigs, raised in a lab. This involves immunological changes as well as making the tissues compatible and fixing blood-clotting issues.

But for that project, the researchers had used a line of "immortal" pig kidney cells, chosen for their ability to survive and divide indefinitely in a dish.

The researchers next aim to overcome the problem of immune rejection. Some of these piglets are still growing, says Yang, and they're still healthy. In their new work the Yang team performed experiments confirming that pig retroviruses can infect human cells-just as another retrovirus, HIV, does with people. Tector says his own team stopped worrying about the viruses years ago, because it is not clear whether the U.S. Food and Drug Administration will require the viruses to be removed prior to transplantation. Still, Denner says, "If it is possible to knock [PERVs] out, you should do it".