You’ve seen designer cosmetics, designer jeans, and designer jewelry. These may all be high-end merchandise, but now, a new type of designer is entering the field. Biologist Luhan Yang is working to design genetically altered pig organs which could be used for human transplantation.
Yang authored the genome-editing technology called CRISPR in 2013. In 2015, she cofounded eGenesis, a biotech company, where her research is conducted. CRISPR is challenged with altering numbers of genes without compromising the viability of the designer pigs. They eliminated the 62 genes from pig cells which prevent pigs from organ donation. Now they are trying to get the surrogate mother sows pregnant with the genetically altered embryos to give birth to healthy piglets.
Last month, Yang visited her native China and the eGenesis pig colony there. The latest good news is that the surrogate mothers didn’t reinfect the fetuses with PERVs (porcine edogenous retroviruses), which could cause tumors and leukemia if transplanted into patients. PERV genes are interwoven into pig cells’ genome. CRISPR has removed 62 PERV genes in pig kidney cells, a record. Removing PERVs is relatively easy. eGenesis ships batches of these cells to China, where each de-PERV’ed pig cell is fused to a pig ovum with the mother’s DNA removed. Xenotransplantation requires large-scale genome engineering, inserting large chunks of human DNA into the pig genome. Up to 12 human genes are also inserted in the ova. These human genes would shield organs from attack by the human immune system and reduce the risk of clots.
Embryos are then implanted into surrogate mothers. So far, one batch of embryos all died, while another batch resulted in several miscarriages. The ethical issues surrounding xenotransplantation have not slowed Yang’s pursuit of pig organs for transplant. “I think it’s a personal choice whether you use a pig organ or die. But you shouldn’t prevent other people from using it,” says Yang. As of the end of March, two of the cloned pig fetuses were just a few weeks from delivery.
Begley, Sharon. “She’s hellbent on solving the organ shortage with ‘designer pigs.’ Just don’t keep her waiting.” STAT, 6 Apr 2017. Web. 6 Apr 2017.