There is a need for organ donors all over the world. Many people lie in hospital beds hoping for a replacement organ. There just aren’t enough available, and no wonder. To get just a few, someone young and healthy would have to die in a way that doesn’t affect their organs. In the U.S. alone, an average of 10 people die every day because there weren’t organs for them.
Scientists have worked with this problem for a while. First, they turned to animals like the monkey as donors. But most of these experiments failed. In 1984, scientists transplanted a baboon heart into a newborn. The heart seemed to work at first, but baby Fae lived for only 20 days. Two more men with livers transplanted from monkeys only lived a little longer, one living for 70 days and the other for 26. These experiments failed because our immune systems recognize the transplanted organs as foreign and attack them.
Recently, however, scientists have had a breakthrough, not with apes, but with…pigs! Pigs have organs of similar size to ours, and they have the same functions. But, as with the ape organs, there are problems. The two main issues are that pig cells are coated with a distinctive sugar that alerts our immune system that there’s an intruder, and that the pig genome carries dormant viruses that could hurt humans. These viruses are called Porcine Endogenous Retroviruses, or PERVs.
For this problem, scientists use a gene-editing technique called CRISPR. They are now able to knock out the gene for the sugars on the cells, and some groups are identifying and trying to cut out some of the PERVs.
It’s a huge task. But progress has been made. One team of scientists identified 45 genes that need to be removed. On August 10th, 2017, 37 piglets lacking some PERVs were born in China. 15 survived. Another big step forward was the creation of a pig lacking 3 PERV genes. 30% of patients should be able to host those organs.
Even though the technology has leapt forward, I wouldn’t count on a porcine organ anytime soon. Scientists have only gotten to testing the pig organs on apes, and those experiments have had mixed results. And even if they could identify all the PERVS and remove them and successfully create a litter of pigs missing the PERVS, there’s no guarantee hospitals and doctors would accept replacement organs from pigs. The scientists definitely have a long battle ahead of them.