Researchers have long thought that if we could grow organs for transplantation, thousands of people who are desperate to get those new organs would no longer languish on waiting lists, and would instead get the help they need immediately. But there are many hurdles to be overcome before we can easily generate human organs that are perfectly functional, and won’t get rejected. New work by scientists at Stanford and UC Davis has taken steps to meet some of those challenges. The researchers were able to successfully grow human stem cells inside of sheep embryos for 28 days, as a proof-of-concept.
An organism that carries cells that have different genetic material is called a chimera. In this case, the chimeric organism, a sheep, would carry genomes from different species; the idea is to implant them with stem cells that could develop into human organs, and then harvest those organs when mature.
This strategy could also help to relieve the problem of organ rejection. When the work was announced by Stanford Geneticist Hiro Nakauchi, the research leader, he emphasized that point. Using stem cells from a patient to grow a new organ would generate a perfect match that posed no threat to the patient’s immune system.
"Although they are formed inside the body of animals, the cells are derived from a patient's own stem cells," Nakauchi said at the annual meeting of the American Association for the Advancement of Science.
There is still much more work to be done before such organs are ready for use in the clinic. The National Institute of Health also does not yet fund this kind of research. However, this research is an important step toward helping the thousands of people that are waiting for a new organ; the scientists have also taken steps to ensure that they are addressing any ethical concerns about the use of chimeras.
Nakauchi told Stanford: “More than 116,000 patients are on the waiting list and 20 people die each day in the United States alone due to a lack of donor organs. Animal-grown organs could transform the lives of thousands of people facing organ failure. I don’t understand why there continues to be resistance. We could help so many people.”
Sources: Stanford, Business Insider