A surgical team led by Dr. Robert Montgomery at New York University’s Longone Health facility has successfully transplanted a pig kidney into a human recipient. It is the first case in which a kidney has been transplanted from a different organism, scientifically known as xenotransplantation , and has not been rejected by the host’s immune system, since the kidney has functioned as it was supposed to: filtering waste and producing urine without greater consequences . This successful demonstration offers a ray of hope to hundreds of thousands of people around the world who are currently on eternal waiting lists for organ transplants.
How was the process?
The transplant involved the use of a pig whose genes had been altered so that its tissues no longer contained a molecule known to trigger almost immediate rejection. The recipient was a brain-dead American patient with signs of kidney dysfunction, whose family agreed to the experiment before her life support was taken away, the researchers said.
First, the new pig kidney attached itself to its blood vessels and was kept outside the body , allowing the researchers to access it and not just monitor it.
The kidney produced “the amount of urine you would expect” from a transplanted human kidney, experts say, and there was no evidence of the early and vigorous rejection seen when unmodified pig kidneys are transplanted into non-human primates.
A significant step
Scientists have been working for decades on the possibility of using animal organs for transplantation, but have been hampered by the huge problem of how to prevent immediate rejection by the human body.
The team hypothesized that removing the pig’s gene for a rejection-triggering carbohydrate, a sugar or glycan molecule, called alpha-galactose, would avoid the problem. The human body attacks and ultimately rejects the transplant when the human immune system detects this foreign substance, so they implanted a pig embryo with a modified gene into a surrogate sow and this gave birth to a pig with a modified immune system . Once adult, the pig also underwent surgery to attach its thymus to its kidney. The thymus is a small gland near the top of the lungs that produces white blood cells. The surgeons then attached the organ to the thigh of the human recipient. There was no rejection.
Scientific data on transplantation have not yet been published and technical evaluation will be necessary before it can be considered a total success. But it is a big step.
Pigs have human-like organs, with the advantage that they are also comparable in size to ours, and are regularly raised for meat consumption, which means that they are less likely to raise ethical concerns among the public than, for For example, organs taken from other primates. And the need for organs for transplantation is increasing in our society.
