A New Hope in Organ Transplantion

Instead of waiting in line for years, could someone needing a kidney transplant get one from a pig? Scientists have been trying to make this possible using gene-editing tools like CRISPR-Cas9. Just last week, a 62-year-old man named Richard Slayman got a genetically modified kidney in the United States (1).

What is Xenotransplantation?

There’s a lot of hope but also caution about xenotransplantation, which is when organs from animals are put into humans. It could help solve the shortage of organs we have now. This idea isn’t new, but scientists can do more now because of gene editing. They changed the kidney given to Slayman in three important ways.

How Gene-Editing Can Help Solve the Problem of Organ Shortage

Explaining why gene editing is needed, Dr. Arvinder Soin, from Medanta Institute of Liver Transplantation, says, “First, some pig genes make sugars that our body fights. These genes had to be removed to stop the body from rejecting the kidney. Second, when organs are put from one species to another, it can cause clotting. The scientists added genes to stop this. Third, pigs have viruses in their genes that humans can get. Scientists removed these viruses too.”

The pig kidney had 69 changes made to its genes. These changes were done by a company called eGenesis, led by George Church from Harvard Medical School. They found a way to fix a big problem with using pig organs—viruses in the pig genes that can infect humans. In 2015, their lab showed they could remove all 62 viruses from a pig’s genes at once using CRISPR. This was a big step forward.

Why are Pigs the Most Suitable Animal Donors?

Pigs are picked for this because their organs are similar in size and function to ours. “But using pig organs comes with challenges,” says Dr. Harsha Jauhari from Sir Ganga Ram Hospital. Our immune system is very complicated. It usually only accepts organs from identical twins. Using pig organs adds new genes that our bodies might not accept. This is a big challenge. Also, pig organs can bring in new infections that don’t happen in humans. This can spread to other people too. So, while it’s a good start, it’s still going to take years to become a normal treatment.”

Slayman had diabetes and high blood pressure, putting him at risk of kidney disease. He got his first kidney transplant in 2018. But after five years, it started to fail, and he needed dialysis again. He got the pig kidney this time because he needed a transplant urgently.

What are the Chances of Survival with Pig Kidney Transplantation?

We don’t know yet how long Slayman’s new kidney will last. Dr. Tatsuo Kawai, who led the surgery, says, “Based on what we know so far, we hope it will last more than two years.” There have been only two pig heart transplants done before, and both patients died a few months later. There have been some experiments with pig liver and kidney too. Doctors from China also transplanted a pig liver into a person who had died around the same time.

Dr. Jauhari thinks xenotransplantation could be a solution for the future, but he’s hopeful about other options too. Scientists are working on growing organs in labs using stem cells. “And maybe by then, we’ll also have better ways to treat diseases,” says Dr. Jauhari.

References:

1. Doctors perform 1st transplant of genetically modified pig kidney to human patient
   
   https://www.pbs.org/newshour/health/doctors-perform-1st-transplant-of-of-genetically-modified-pig-kidney-to-human-patient

Source-Medindia