Since then, several attempts were witnessed when the scientific community bowed from primates to pigs for bridging the species gap. Moreover, as
Several biotech companies have carried out the development of suitable pig organs for transplantation, to bring a revolution in the care of patients.
It is estimated that >90,000 people await kidney transplants in the U.S., among which 12 die every day, as per the United Network for Organ Sharing.
However, xenotransplant may invite an entity called graft rejection, where the recipient’s body attacks the new grafted organ as a foreign body/obstacle or infection. This results in serious immune reactions that may even be fatal.
A subsidiary of United Therapeutics Corp’s (UTHR.O) – Revivicor unit advances the barricade by genetically engineering the pig (dubbed GalSafe). The pig lacks a gene responsible for producing a sugar (alpha-gal) that is responsible for provoking the immediate attack on the human immune system post-transplantation.
Food and Drug Administration (FDA) had also approved the safety of the genetic alteration in the Revivicor pigs for humans (food consumption and medicine) in December 2020. However, FDA warranted further validation for the use of pig organs in transplantation.
“This is an important step forward in realizing the promise of xenotransplantation, which will save thousands of lives each year in the not-too-distant future,” says United Therapeutics CEO Martine Rothblatt in a statement.
First Pig-to-Human Transplant
The valves of a pig’s heart have successfully been in use for humans for decades. Moreover, other organs like skin grafts, pig corneas, and a blood thinner drug – heparin have been successfully derived from pigs.
The present surgical team utilized the body of a brain-dead deceased woman (upon her family’s consent) on a ventilator who had signs of kidney dysfunction. The woman had already consented to her wish to donate her organs, but they failed to meet the criteria for donation.
Due to the increasing organ shortage of humans, the scientific community explores pigs to surmount the barriers. However, significant concern hovers with the very speculation of graft rejection.
The present team overpowered this by the use of gene-editing in the animal that bypasses the immune system attack. The team tested the recipient’s immune system for an immediate rejection for three days by attaching the pig kidney to a pair of large blood vessels outside the body of the deceased recipient.
To their anticipation, the graft witnessed no failure and the recipient’s creatinine level (an indicator of poor kidney function) reverted to normal post-transplant. The transplanted kidney also produced urine with normal waste filtering capacity. This serves as a major advancement in the medical transplantation field to ease a dire scarcity of human organs.
“It had absolutely normal function. It didn’t have this immediate rejection that we have worried about,” says Dr. Robert Montgomery who led the surgical team at NYU Langone Health and is a recipient of heart transplantation himself.
Revolutionary Era of Transplantation – Key Points
Despite substantial trials on public awareness for organ donation, there is no significant improvement in the figures of organ donors but rather faces even a down curve.
It is stated that almost two-thirds of the Americans assent for cross-species transplantation as a feasible prospect to overcome the shortage of organ and tissue transplantation as per a National Kidney Foundation survey in 1997.
In addition, the use of genetic advancements by the present team overcomes even the preeminent barrier of graft rejection. Although the transplant experiment included only a single transplant of the kidney, it paves the way for safer trials in critically ill patients with end-stage kidney failure.
With proper addressal of appropriate safeguards, xenotransplantation may soon become a promising reality to medical treatment.
- XENOTRANSPLANTATION: The Benefits and Risks of Special Organ Transplantation
- Physiologic and Immunologic Hurdles to Xenotransplantation – (https://jasn.asnjournals.org/content/jnephrol/12/1/182.full.pdf?with-ds=yes)