A subgroup of a Japanese health ministry council on Friday approved a proposal to lift a ban on transplanting cells and organs from pigs to humans.

Making the proposal to the subgroup, a ministry study team called for a revision to transplantation guidelines because no such transplantation overseas has caused infections or other problems.

In Japan, pig-to-human transplantation is being considered as an option to ease shortages of donated organs, cells and other body parts.

Outside Japan, pancreatic islet cells from pigs have been transplanted into Type 1 diabetes patients. Some researchers in Japan are aiming to carry out such transplantation within a few years.

In 2001, the study team created the current guidelines, which effectively prohibit pig-to-human transplantation, citing concern that viruses incorporated into pig genes could cause new infectious diseases in humans.

The guidelines will be revised to require the use of pigs with less incorporated virus and lifelong research into patients with transplanted pig tissue in order to watch for infectious diseases.

The subgroup also approved a proposal by a different ministry study team on safety standards for clinical research in which induced pluripotent stem cells are converted into other cells for transplantation.

Under the standards, researchers will be required to confirm that the cells they will transplant do not contain genetic mutations related to cancer and that the cells do not cause tumors when transplanted into mice.