One Step Closer to Kidney Transplants From Pigs

A staggering 107,000 Americans await a lifesaving transplant. 90,000. There is a clear shortage of organs.

New York University’s transplant surgeons made a modest but important step towards addressing the shortage of organs from different species in October. A kidney was transplanted from a donor pig. The kidney had not been modified genetically to express alpha-gal (a carbohydrate that is common in humans, but it also occurs in primates). Transplants of other mammals can cause a severe immune reaction in infants, who develop antibodies against alpha-gal due to their gut microbiota.

NYU surgeons attached a modified pig kidney (with permission from the woman’s family) to blood vessels in the deceased woman’s upper leg. The ventilator was used to maintain her bodily functions. For 54 hours, researchers observed her kidney. Researchers observed the kidney for 54 hours. It produced urine and other waste products, such as creatinine. There were no signs or symptoms of immune rejection.

The results of an experiment using kidneys from more genetically-modified pigs was reported by the Massachusetts General Hospital transplant team in July 2021. The pigs are not genetically modified to express alpha-gal and two other carbohydrate types that can be attacked by the body. They also have several genes from humans that control immune response and bloodcoagulation. Researchers transplanted the kidneys of the pigs to macaque monkeys. One died within two days; three other remained alive for 135, 265, or 316 days.

Researchers are trying to address a problem with xenotransplantation. Xenotransplantation is any procedure in which human patients receive non-human organs or tissues. For example, in the 1960s, a Tulane University surgeon Keith Reemtsma transplanted 13 chimpanzee renals into thirteen patients. The majority of the transplants failed in four to eight weeks. However, one survived for nine months. Leonard Bailey, a Loma Linda University Medical Centre heart surgeon transplanted the baboon’s heart to “Baby Fae” in 1985. He had performed this procedure on a baby who was prematurely born with a fatal defect. After 20 days, the heart died from acute immune rejection.

University of Alabama transplant surgeons David Cooper, and HidetakaHara recommended in September EBioMedicine This article explains that patients who don’t expect to live to see a donor kidney for a long time would be able to benefit from dialysis-free support provided by a pig renal. It would improve the transplantation of organs from animals.

Roy Calne, a Cambridge University transplant surgeon, suggested in 1995 that xenotransplantation was “just around the corner”, but may take a while. Scientists are closer to completing the circle, according to NYU’s results.