Apr 26, 1999

Questions and Comments
Animal Parts: Learning the Tricks by Karen Hopkin


They’re the stuff of mythology: satyrs, free-spirited critters with the head of a man and the body of a goat, that prance through the woods, cracking wise and looking for trouble. Or the Minotaur, a nasty beast with a man’s body and a bull’s head. Or mermaids, sweet ladies with fish tails and a fondness for song.

Now, we know better. There’s no such thing as people who are part human, part animal. Right?
In fact, more than a few people today are walking around with a bit of the beast in them. Over the past five years, some 200 people have received transplants of animal cells or tissues to replace or assist their own failing organs.

How did this strange arrangement come to pass?
Doctors have been experimenting with xenotranplantation—the practice of transplanting parts from animals to humans—for a long time, with precious little success. But that may soon change. Physicians and researchers are looking to xenotransplantation as a possible solution to the chronic shortage of donor organs for people with failing kidneys, livers, or hearts, and they hope to battle chronic diseases such as diabetes and Parkinson’s with implants of animal cells.

But the road toward successful xenotransplantation has not been smooth, nor is it complete. So far, few whole-organ transplants from an animals have worked for very long, because the human immune system is quick to destroy foreign tissue. Despite these failures, researchers doggedly press on in the hope that learning more about how the immune system recognizes and attacks foreign cells and organs will reveal how physicians can put the brakes on transplant rejection. Click your way through the timeline to find out more.