Scientists Grow Human Organs Inside Pigs
Scientists in the U.S plan to grow human cells inside pigs with the possibility of creating organs for transplants. Daniel Garry, a cardiologist who is leading the chimera experiment at the University of Minnesota says “We can make an animal without a heart. We have engineered pigs that lack skeletal muscles and blood vessels”. Although these pigs aren’t practical they can be adequately formed if cells from a normal pig embryo are added to them. He said that the U.S. Army have given him a $1.4 million grant towards researching growing human hearts in pigs.
Hiromitsu Nakauchi, a stem-cell biologist at Stanford University, tried to produce human-sheep chimeras this year. He said “If the extent of human cells is 0.5 percent, it’s very unlikely to get thinking pigs or standing sheep, but if it’s large, like 40 percent, then we’d have to do something about that.” Six years ago when Nakauchi was working in Japan, he used mice whose pancreas were composed completely from rat cells. He says “if it works as it does in rodents, we should be able to have a pig with a human organ.”
In 2013 Nakauchi decided to move to the U.S because Japanese regulators were slow to approve his idea of pig chimeras. The California Institute of Regenerative Medicine gave Stanford University a $6 million fund to recruit Nakauchi. However, The National Institute of Health is concerned that human-animal chimeras could cause the pigs to develop human brain cells. The NIH has requested that Nakauchi and the other researchers clarify the details of their work. The chimeric embryos are placed in incubators and micro-needles are used to inject the human cells into them. Nakauchi says “We need a special consent if we’re injecting into animals, so I try to use my own.” The human cells he is using are called Induced pluripotent stem cells (iPSCs) which are adult cells that have been genetically reprogrammed to an embryonic stem cell by being forced to express genes and factors important for maintaining the essential properties of embryonic stem cells. He hopes that people who are extremely ill and waiting for an organ donation will soon be able to order a chimera. “I really don’t see much risk to society,” he says.
The NIH wants the researchers to be certain that human cells can increase and be formed effectively in pig’s bodies. This may be difficult to prove because although mice and rats are similar genetically, humans and pigs are very different. In order to confirm this, Pablo Ross, a veterinarian and developmental biologist at the University of California, Davis, impregnated some of the pigs and sheep. He said that he placed six sets of pig-human embryos into sows in association with the Salk Institute and created another eight pregnancies of sheep-human embryos with Nakauchi.
Ross says that they only need to grow the embryonic pig to half an inch long to see if the human cells are working effectively in the pigs organs. He added “We don’t want to grow them to stages we don’t need to, since that would be more controversial,” says Ross. “My view is that the contribution of human cells is going to be minimal, maybe 3 percent, maybe 5 percent, but what if they contributed to 100 percent of the brain? What if the embryo that develops is mostly human? It’s something that we don’t expect, but no one has done this experiment, so we can’t rule it out.”
Last year there were 2,015 people in Ireland receiving dialysis, and 2,314 people awaiting a kidney transplant. Approximately 266 organ transplants occurred in Ireland, which included lung, liver, kidney, heart and pancreas transplants. Hopefully with this new research the pig-human organ donations will work effectively and decrease the number of people waiting for organ donations in Ireland, and throughout the rest of the world.
Hashtags: #PigOrgans 
