Japanese Research Team Planning Pig Kidney Transplant into Human Fetus

Yomiuri Shimbun file photo
The Jikei University School of Medicine

TOKYO (Jiji Press) — A Japanese team is planning a clinical study to transplant a pig kidney into a fetus with a severe kidney disease, it was learned Tuesday.

The team aims to file the plan with a government committee as early as this year, hoping that the transplanted kidney will help buy time until dialysis becomes possible after delivery.

If realized, it will be Japan’s first case of animal-to-human transplantation, or xenotransplantation, of an organ.

The team includes members from the Jikei University School of Medicine and the National Center for Child Health and Development.

Takashi Yokoo, professor at the university, said that the clinical study will cover a fetus with Potter syndrome, which makes an unborn baby unable to produce a sufficient amount of urine.

Under the team’s plan, a 2-millimeter kidney removed from a pig fetus will be transplanted into a human fetus about four weeks before the expected date of delivery. After the surgery, blood vessels of the unborn baby are expected to penetrate into the pig’s kidney, allowing the baby to produce about several tens of milliliters of urine per day.

The urine will be discharged through a tube after the fetus is delivered. After a few weeks, the transplanted kidney will be removed when it becomes possible to give dialysis to the baby safely.

There are ethical problems surrounding xenotransplantation, such as the use of animals for medical purposes. Therefore, the university and others plan to hold briefings for the general public in summer. The transplantation plan will be submitted to the government committee if it passes ethical reviews planned at related facilities in autumn.

Xenotransplantation using pig organs is attracting attention as a solution to the current organ donor shortage. Heart xenotransplants have already been performed abroad.

“Until now, we had no choice but to watch [suffering] babies die,” Yokoo said. “We hope the transplantation of pig kidneys will add a treatment option, which will serve as hope.”