Every day 22 Americans who are awaiting an organ transplant die from organ failure. This is one of the many reasons scientists have turned to alternative avenues in hopes of harvesting sustainable and healthy organs, according to BBC.
Earlier this year, researchers at the University of California, Davis furthered their attempts to grow a human pancreas inside of a pig using stem cell technology. The UC Davis research team injected human cells into the embryo of a one day old pig fetus and let it develop for 28 days. As they monitored and analyzed the human-pig pancreas, they were able to gain valuable insight from the organ before terminating the process. Pablo Ross, a reproductive biologist who is leading the research said in a recent interview:
"Our hope is that this pig embryo will develop normally but the pancreas will be made almost exclusively out of human cells and could be compatible with a patient for transplantation."
They have yet to allow the fetus to be born, but so far their research suggests that if pig were to live, it would behave and act like any other pig. The only difference being that it would host a genetically modified human pancreas instead of a pig one. Robin Lovell-Badge, a geneticist at the Francis Crick Institute in London said:
“You are basically creating a vacuum, a hole, so that the human cells respond to the right cues, they make a pancreas. The pig cells can’t. But what we don’t know, and this is what they need to look at, is whether the human cells can also contribute substantially to other tissues, and particularly they are worried about the brain.”
While the recent trials look promising, many have raised concern about the practice in the past. Last year in September, the NIH imposed a moratorium on funding of such experiments until more information was offered regarding its implications.
Their main concern was that the human cells could potentially migrate into the developing pig's brain and, perhaps, make it more human - or another species altogether. Ross said:
"We think there is very low potential for a human brain to grow, but this is something we will be investigating."
The researchers had attempted earlier trials on pigs, but without first creating the genetic niche. They found that without injecting the human cells into embryo, the the human cells spread to various parts of the fetus and started to “compete” with the pig’s cells. Once they deleted the essential pig gene that made up the pancreas, however, the human cells began developing without resistance of the pig’s genetics.
Additional concern was raised by Peter Stevenson, from Compassion in World Farming, who told BBC:
“I’m nervous about opening up a new source of animal suffering. Let’s first get many more people to donate organs. If there is still a shortage after that, we can consider using pigs, but on the basis that we eat less meat so that there is no overall increase in the number of pigs being used for human purposes.”
Many are also worried about the potential risk of animal viruses that could transition if a human were to use an organ harvested in a pig. However, researchers from Harvard Medical School revealed last year that gene-editing technology could deactivate over 60 retrovirus genes in pigs, which is at the very least, a step in the right direction.
There are currently 120,000 Americans that await a transplant of some kind. Stem cell technology and the notion of harvesting human organs inside of animals may seem absurd to some, but it offers alluring potential and is at least a conversation that should be brought to the table.
Aptly named, Enclothed Cognition is the official Medelita blog for medical professionals interested in topics relevant to a discerning and inquisitive audience. Medelita was founded by a licensed clinician who felt strongly about the connection between focus, poise and appearance.