Scientists have demonstrated that genetically edited pig kidneys transplanted into a human can continue to function for at least a week, with no sign of rejection. The breakthrough case study could help reduce organ waitlists and resulting deaths.
In cases of advanced disease, organ transplantation is often the only option, but finding enough suitable donors remains a challenge. A technique called “xenotransplantation” looks to widen the pool beyond human donors, with pigs the most promising due to their similar-sized organs. To reduce the risk of rejection, the organs are genetically edited to knock out certain pig genes and insert some human ones.
Scientists have seen some success recently. Last year, the first pig-to-human heart transplant was performed in a live patient, who went on to live for two more months before passing away due to heart failure. Other teams implanted pig kidneys and hearts into patients who had been declared brain-dead, with the organs functioning and showing no signs of rejection over a three-day experiment period where the patients were kept on life support. They had of course previously opted in to donate their bodies to the experiments.
The new study, from scientists at the University of Alabama, extended the experiment to a full week. The patient was a man in his 50s who had a history of chronic kidney disease, had exhausted all other options, and had been declared brain-dead. He received pig kidneys that had undergone 10 gene modifications – four that knocked out pig genes that can cause rejection, and insertions of six human genes that prevent coagulation.
Over the course of seven days, biomarkers indicated that the transplanted kidneys were functioning well. They successfully produced urine, and also improved creatinine clearance from the blood, which is a key measure of kidney function. No evidence was found of microscopic blood clots forming in the kidneys either.
While there’s still plenty more work to be done before this procedure might be performed regularly in the clinic, this is an important step towards potentially reducing waiting lists and the premature deaths of people on them.
“Xenotransplantation has, historically, largely failed due to hyperacute rejection following surgery, even with the use of immunosuppressive drugs used to control this process,” said Dr. Roger Lord, senior lecturer of Medical Sciences at the Australian Catholic University, who was not involved in the study. “This case study provides important preliminary evidence that these genetically modified kidneys can function normally following xenotransplantation and offers hope to those on waiting lists for kidney transplantation."
The research was published in the journal JAMA Surgery.
Source: Scimex
