Among the avenues followed to respond to the challenge of the lack of grafts, that of “xenograft” (transplantation of an organ from another species) has just reached a historic milestone. For the first time, a kidney from a pig has been successfully transplanted into a human patient with end-stage renal failure. The latter should soon be able to return home, announced Thursday the Massachusetts General Hospital (MGH), where the feat was achieved.
At 62 years old, Rick Slayman had long suffered from kidney problems due to his type 2 diabetes and hypertension. A first “classic” kidney transplant allowed him to do without dialysis for 5 years, but the deterioration of the graft put him back on the long list of candidates for a new transplant in May 2023. It was then that his nephrologist offered him an alternative: accept the kidney of a pig genetically modified to be tolerated by the human body. Such organs had already been transplanted, and worked, into humans… in a state of brain death.
The operation carried out by the team of Dr Leonardo Riella, Tatsuo Kawai and Nahel Elias lasted four hours. The graft used comes from a pig raised by the specialist company eGenesis in Cambridge, which has been collaborating with the MGH on the subject for several years. Their joint research carried out on monkeys transplanted with pig kidneys was presented in October in Nature. Pigs raised by eGenesis are genetically modified using the Crispr Cas-9 genome editing technique to rid the organ of pig-specific retroviruses that can infect humans, as well as to remove certain pig genes and add genes humans. No less than 69 modifications are necessary for the organ to be tolerated by a human organism.
“For me, it was both an opportunity [to get better], but also a way to give hope to thousands of people waiting for a transplant to survive,” the patient said in a statement of MGH. The medical team, for its part, praised the “courage” of this pioneer. “The success of this transplant is the culmination of the efforts of thousands of scientists and doctors over several decades,” added Tatsuo Kawai, surgeon at Massachusetts General Hospital.
“It’s extraordinary, spectacular,” greets Professor Christian Combe, nephrologist and president of the Kidney Foundation, while recalling that “we must necessarily remain cautious since we only have five days of hindsight at this stage.” “Their work shows that they have maximized the immunological compatibility between humans and pigs, they have given themselves a lot of chances for it to work,” he emphasizes.
The very first transplant of a humanized animal organ took place in January 2022 in Maryland in the United States. David Bennett had received a genetically modified heart from a pig which had functioned properly for seven weeks before deteriorating, leading to the patient’s death.
“The pig has many advantages: it is a relatively simple animal to raise, which grows quickly and presents organs of similar size to those of a human adult in around six months,” explains Professor Sébastien Dharancy of Lille University Hospital, responsible for transplant activity in the Lille region, who did not participate in this research. Furthermore, they have physiological and anatomical similarities with humans.” “The kidney has an important role in regulating the body’s water and salt composition. However, there is an interesting compatibility between the hormonal receptors of pigs and the human hormones involved in this mechanism,” adds Professor Combe.
In France, 3,377 kidney transplants were carried out in 2022, but 9,800 patients were still on the active waiting list as of January 1, 2023.
