Its real offensive when someone says “pig-ugly”. Pigs are just as cute as your conventional pets, and contrary to popular belief they are intelligent, highly social, and surprisingly trainable. As if that wasn’t enough to make you wanta take them home, feed them truffles and tickle their tiny tummies, they are very much like us- no it’s not what you’re thinking- they have organs that are the same size as human organs and function pretty much the same way.
Therefore, scientists for decades now have been dreaming of transplanting organs from pigs into people- an idea known as xenotransplantation.
Xenotransplantation is transplanting animal organs into people. It has been seen as one possible way to ease the human organ shortage. But almost all attempts to implant animal organs into people have failed. In 1984, “Baby Fae” famously received a heart transplant from a baboon and died 20 days later.
Also, another flaw in this grand plan is that pigs can harbour harmful microbes. When pig cells are grown in a dish along with human cells, viruses known as porcine endogenous retroviruses or PERVs have crossed into the human cells, suggesting they would do the same if pig organs were put
into people. If this happened, it may cause diseases like cancer.Now eGenesis, spun out of Harvard geneticist George Church’s lab, may have figured out how to get rid of these species-jumping viruses. Luhan Yang, cofounder and chief scientific officer at eGenesis, says her team wanted to deactivate this group of viruses to see if the pigs would develop normally.
Using the gene-editing tool CRISPR, Yang and her team were able to disable all 25 copies of the viruses in pig embryos. They then implanted the embryos into female pigs, which gave birth to piglets that didn’t harbor the viruses. The company has produced 37 pigs this way and has been monitoring them for four months. So far, the resulting animals are healthy and virus-free.
The technical feat has, ironically, inspired some dread among those enthusiastic about xenotransplantation, the transfer of nonhuman animal organs into people. With the actual risk of PERVs uncertain, some worry that the extra editing will needlessly add complexity to the already-difficult organ development process, especially if the regulators at the U.S.
Food and Drug Administration (FDA) insist on PERV-free pigs for future human experiments. “If this is required, it will add to the time before pigs can be used for transplants in patients in desperate need,” says transplant immunologist David Cooper of the University of Alabama at Birmingham.
eGenesis says it will continue to monitor the piglets for any long-term effects and, according to Yang, will also “further engineer the PERV-free pig strain to deliver safe and effective xenotransplantation.”
The team further, plans to make pigs that are altered to a greater extent, to make them more immunologically similar to people. In theory, this should make transplanted organs less prone to attack by a recipient’s immune system.
Yang says eGenesis is also using CRISPR to make modifications to genes involved in the immune system. However, she says human tests of an organ produced in one of these gene-edited pigs are still years away.
