Medical researchers have been making advancements in the field of organ transplantation using pigs as the primary donors of kidneys.
Organ transplantation is the medical practice of transferring an organ from one person to another. Typically, donors and recipients are matched on the basis of blood type and compatibility of the organ with the recipient’s immune system.
The best organ donor for someone would be an identical twin, due to similar blood types and gene expression in both siblings, but not everyone has a twin, let alone an identical one. These advancements can reduce the wait time for someone in need of an organ.
Xenotransplantation is the practice of taking an organ from an animal of one species and putting that organ into an animal of another species. This has never been the preferred method of organ transplantation because organ donor and recipient matching can be difficult, and even more so with an organ coming from a species that can have different physiology than the recipient.
The advancements in xenotransplantation include editing the genetics of pigs, namely their kidneys. The goal of editing these genes is to place the kidney in the recipient without having a severe immune response to the organ.
The first experiments involving pig kidney transplantation in monkeys took place in the 90s and resulted in a quick and severe reaction in a monkeys’ system. Researchers discovered that this was because pigs express different proteins inside and on the surface of their cells that primates and humans do not. This is how they got the idea to knock these genes out of the pig when it is at an embryonic level.
The record for the longest time with a xenotransplanted organ belongs to Edyth Parker. Parker, a Louisiana schoolteacher, received a chimpanzee kidney in 1964. Her surgery was done at Charity Hospital in New Orleans and her autopsy showed that no complications came from the kidney.
Parker died one day before her nine-month anniversary of having the organ. After her death, the practice of using chimpanzee organs in humans was prohibited by researchers.
The longest human clinical trial of pig kidney xenotransplantation method was volunteered by Towana Looney in November of last year. She originally gave one of her kidneys to her mother. She signed up to receive a kidney with 10 gene edits from United Therapeutics and had the surgery done at NYU Langone Health.
After four months and nine days, Looney had the organ removed after it had stopped functioning. She was on immunosuppressants to help alleviate any reaction, but after the failure, doctors and researchers advised that the kidney be removed and that she return to dialysis as she was before having the kidney.
Another recent case is that of Tim Andrews, who received a kidney with 69 gene edits from EGenesis. Andrews’ kidney lasted for nearly nine months, just short of Parker’s record for a xenotransplantation with no fatal repercussions. Like Looney, Andrews was on dialysis before the transplant and used immunosuppressants during his time with the new kidney. It finally stopped functioning, leading to the kidney’s removal.
With these current cases, more information on how the human immune system reacts to these genetically-edited organs are being discovered and could help numerous people who are in need of an organ but cannot find someone to match with.