London: Human organs could soon be grown inside pigs for use in transplant operations, as scientists claim to have made a stem cell breakthrough, allowing them to create genetically altered animals that have organs belonging to another species.
The technique, developed by a team at the University of Tokyo in Japan, involves injecting stem cells of an animal into the embryos of another animal that had been genetically altered so they could not produce their own organs.
The researchers said the technique could allow pigs to grow human organs from patient`s stem cells for use as transplants, the Daily Telegraph reported.
By using a patient`s own stem cells it could help to reduce the risk of the transplanted organ being rejected while also providing a plentiful supply of donor organs, they said.
Professor Hiromitsu Nakauchi, who led the research, said: "Our ultimate goal is to generate human organs from induced pluripotent stem cells.
"The technique, called blastocyst complementation, provides us with a novel approach for organ supply. We have successfully tried it between mice and rats. We are now rather
confident in generating functional human organs using this approach."
Professor Nakauchi, who presented the study at the annual conference of the European Society of Human Genetics, used a type of adult stem cell known as induced pluripotent
stem cells, which can be taken from a sample of tissue such as the skin and encouraged to grow into any type of cell found in the body.
Together with his colleagues, he injected these cells taken from rats into the embryos, or blastocysts as they can be called, of mice that were unable to grow their on pancreas, the organ that produces important hormones including insulin.
When the mice matured to adulthood, they showed no signs of diabetes and had developed a pancreas that was almost entirely formed from the injected rat stem cells.
The scientists claimed the rat stem cells grew in the niche left by the absent mouse pancreas and so almost any organ could be produced in this way.
If replicated using human stem cells, the technique could produce a way of treating diabetic patients by providing a way of replacing their pancreas.
Currently, researchers are not allowed to create human embryos that lack the ability to grow organs and so they hope to do the same using pigs.
Professor Nakauchi said they hoped to further test the technique by growing other organs and were also seeking permission to use human stem cells.
They have, however, already managed to produce pigs that were able to generate human blood by injecting blood stem cells from humans into pig foetuses.
Prof Nakauchi said: "For ethical reasons we cannot make an organ deficient human embryo and use it for blastocyst complementation."
"So to make use of this system to generate human organs, we must use this technique using blastocysts of livestock animals such as pigs instead," he added.