Scientists Are Raising Human-Sheep Hybrids for Organ Harvesting
Consider the following: roughly 115,000 people are waiting for an organ transplant this very moment. Every ten minutes, a new person joins this list.
Meanwhile, about twenty people on that list die each day. A lot of people need new organs, and there simply aren't enough to go around – unless we start growing our own (or lay down some grisly organ re-appropriation laws).
Enter: the sheep.
Two scientists, Hiro Nakauchi from Stanford University and Pablo Ross from the University of California, recently appeared at the American Association for the Advancement of Science to discuss their work, which involves transplanting human stem cells into sheep embryos to create sheep whose cells are partly human. The initial goal is for the sheep's cells to be 1% human. (Right now that ratio is about 1 in 10,000.) The ultimate goal – at least for now – is to create a sheep whose pancreas can be used to replace that of a diabetic human.
One of the most difficult hurdles of organ transplants is that the body's immune system often registers the foreign tissue as a threat and rejects the organ. Immunosuppressant drugs can somewhat mitigate this reaction, but have their own dangerous side effects, including a higher risk of infection. The advantage of using sheep-grown organs is that a person's own cells can be used as the basis for the new organ, which theoretically decreases that risk of rejection.
The hybrid organ transplant method has been shown to be effective with mice organs grown in rats. According to Nakauchi, "We have already generated a mouse pancreas in rats and then transplanted those in to diabetic mouse and were able to show almost a complete cure without any immunosuppressants." Human-sheep organs may prove to be more difficult, but Nakauchi is optimistic: "It could take five years or it could take ten years, but I think eventually we will be able to do this."
And that could make a big difference in twenty lives, and their families' lives, every single day.