The numbers are grim. And many more patients could benefit from organ transplants than ever make the waiting list, either because they are too sick or too healthy to qualify. One promising solution to this medical predicament is to harvest organs from suitable animals and use them for human transplant. In preliminary experiments, these companies have already implanted animal cells in human volunteers to treat such diseases as Parkinson's and epilepsy.
Researchers plan to start whole-organ clinical trials in the next two to three years.
The use of animal organs in human transplants is not exactly new. Still, medical researchers quietly pressed ahead, and their efforts may soon pay off. But transplanting tissues from pigs to people does present a few problems. The cause of this reaction is a sugar called alpha-gal that laces the surface of every pig cell. Since human cells don't make this sugar, the immune system produces antibodies against it and kills all cells bearing it.