How US researchers performed pig kidney transplant in human patient

New York: Researchers at the University of Alabama at Birmingham, US, have successfully conducted a transplant of pig kidneys into a brain-dead human. In the days-long experiment, the organs implanted on a 57-year-old male brain-dead patient produced urine and were not rejected. However, this is not the first such surgery.

In September 2021, a study published in the American Journal of Transplantation showed the transplantation of a gene-edited pig’s two kidneys onto a brain-dead patient. Again in October, doctors at NYU Langone Health, New York performed a similar surgery. According to scientists at UAB, their surgery is unique as many medical science advances underlie it, including the 10-gene pig.

The major question is can a kidney from a pig tolerate an adult human environment. Blood pressure is one hurdle because non-human primates and pigs have lower mean arterial blood pressures than adult humans. Hyperacute rejection occurs within minutes if the recipient’s immune system recognises a donor organ as foreign, said UAB transplant surgeon Paige Porrett, Associate Professor. Without the human preclinical model, surgeons could not be sure that vascular integrity would hold up after the transplant.

Equally important, the UAB researchers said, was the relative hemodynamic stability of the decedent upon reperfusion, indicating that washout of inflammatory mediators from the xenograft did not provoke cardiovascular collapse. The experiment also tested whether life-threatening complications might occur during surgery.

In the experiment, 10 genes were changed in the donor pig. Four are disabled pig genes, also known as knockouts. Six are human genes that have been cloned into the pigs, also known as knock-ins.

Although the transplanted kidney filtered waste and produced urine as was expected, it was attached to a blood vessel in the recipient’s upper leg rather than implanted in the abdomen.The researchers also ensured that the donor pig was raised in a pathogen-free facility.