Photo/Illutration The first genetically modified pigs born in Japan (Provided by Meiji University professor Hiroshi Nagashima)

Japanese researchers said they have produced three piglets cloned from a pig that was genetically modified to prevent rejection of its organs in transplants to humans.

PorMedTec Co., a Kawasaki-based company established by the Meiji University International Institute for Bio-Resource Research, said on Feb. 13 that the three piglets were born by C-section on Feb. 11.

A team consisting of researchers from Kagoshima University and Kyoto Prefectural University of Medicine plans to transplant the pigs’ kidneys into monkeys to verify the safety of the organs. If all goes well, they hope to start the operations this summer.

The eventual goal is to transplant pig kidneys into humans.

The original genetically modified pig was produced by U.S. biotechnology company eGenesis.

In September 2023, PorMedTec received cells from the pig and produced cloned fertilized eggs.

The eggs were transplanted into the uterus of an adult sow, and pregnancy was confirmed.

Normal pig organs are usually immediately rejected when transplanted into humans. To overcome this problem, eGenesis modified 10 different genes in the pig.

In the United States, experiments have already been conducted to transplant kidneys from such genetically modified pigs into monkeys.

In October 2023, it was reported that these monkeys survived for up to two years or longer after the transplant.

These were promising results for the field of xenotransplantation, the transplantation of animal organs into humans.

Hisashi Sahara, an associate professor at Kagoshima University who leads the pig kidney transplant team, said: “It is necessary to confirm in Japan that pathogen testing of pigs, breeding management, transportation and transplantation processes can truly be carried out without problems.

“It is important to take firm steps in Japan while fully assessing what is important.”

According to Hiroshi Nagashima, a professor at Meiji University who founded PorMedTec, the goal is to transplant pig kidneys into humans by 2025 and to later perform transplants of pig hearts.

“It has been thought that the realization of xenotransplantation in Japan is a story for the future, but I believe that the best way to promote it is for us to actually create pigs (for organ transplantation),” Nagashima said.

The limited number of donated human organs has been a global health issue, particularly in Japan, where only about 3 percent of organ-failure patients receive organs from brain-dead patients.

Xenotransplantation has long been studied, but preventing rejection of the organs has long been a problem.

In the 2010s, genome editing, a technology that efficiently modifies genes, emerged, and pigs with multiple modifications were developed for organ transplants.

In 2022, the University of Maryland announced it had transplanted a genetically modified pig heart to a patient with end stage heart failure.

The patient died after about two months, but the operation attracted a great deal of attention as a step closer to realizing xenotransplantation.

The university performed a second pig heart transplant in September 2023, and the patient died 40 days later.

The University of Alabama and New York University have reported a total of five studies involving transplants of kidneys from genetically modified pigs into people who were brain dead.

Revivicor Inc., a subsidiary of United Therapeutics Corp., a U.S. company, also produces genetically modified pigs for transplants of hearts and kidneys.

In January this year, eGenesis announced that it had conducted a study in which a genetically engineered pig liver was connected to a brain dead person.

The company said no rejection was observed during a 72-hour observation period.

(This article was written by Kenta Noguchi and Kazuya Goto.)

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