Would you consider receiving a kidney transplant from an animal? Science has come a long way and it now may be possible to obtain a safe kidney transplant from a pig. 

Dr. Jayme Locke, the lead surgeon behind the first successful transplant of a pig kidney, explains xenotransplantation (an organ transplant from one species to another) in the National Kidney Foundation’s podcast, Hot Topics in Kidney Health. Learn more about how it works and why it is needed. 

Why is xenotransplantation needed?

There are 660,000 people living with kidney failure, and 100,000 on the kidney transplant list. These numbers are on the rise and many chronic kidney disease (CKD) patients go undiagnosed until the late stages of the disease. According to Locke, this is leading to a kidney organ shortage, not just in the United States but throughout the world.

“It’s sort of an unmitigated crisis,” Locke says, “and it’s really challenging for me as a transplant surgeon…to know that even those individuals on the waitlist are going to really struggle to find an organ.” 

Why do pig kidneys work?

Judging by our different outer appearances, it may be hard to believe that a pig kidney and a human kidney are very similar, but Locke explains the main similarities between the two. Pig and human kidneys:

• Have similar blood flow
• Can both balance fluids and electrolytes
• Can handle the same types of foods
• Have similar estimated glomerular filtration rates (a measure of kidney function) 

Like human-to-human transplants, there is always a risk of the transplanted kidney being attacked by the immune system and rejected. To overcome this concern, scientists created the UKidney™, a genetically modified pig kidney. By removing three genes from the pig DNA and adding six human genes, the chances of a pig kidney transplant being rejected are reduced. 

What happened with the first pig kidney transplant?

After years of work by scientists, there was only one way to accurately determine its effectiveness, and that was to perform a transplant. Due to the risk, researchers wanted to conduct the transplant on someone who had been declared brain dead. That’s when Jim Parson was identified and, with his family’s permission, the surgery was performed. For 77 hours after surgery, the findings were a success and the kidney worked the entire time. 

Locke remembers the moments after the transplant and says, “When we took the clamps off and restored blood flow–that kidney turned pink, and it stayed pink. Then 20 minutes later, it made urine. I don’t even know how to characterize it, but it was just remarkable.”

When will pig kidney transplants be available?

Following the success of the first transplant with Jim Parson, researchers feel confident they are heading in the right direction. The next steps are getting approval from the U.S. Food and Drug Administration and the UAB’s Institutional Review Board for Human Use to perform living human clinical trials. 

It may still be several years before pig transplants are an option for the general public. In the meantime, getting an early diagnosis of CKD and receiving treatment sooner can help delay the disease’s progress. Learn more about your risk for CKD by taking this one-minute quiz. Always let your doctor know of your concerns. Lab tests are necessary for an accurate diagnosis.

*Pig Kidneys in Humans? Xenotransplantation Explained. (2022, June 18). National Kidney Foundation. Retrieved from https://www.kidney.org/newsletter/pig-kidneys-humans-xenotransplantation-explained