The science of transplanting human organs and brain cells into animals is becoming more common. But why is this being done and what are the ramifications of doing this? Are we wasting precious organs that could be put into humans that need them?

Sheep
Photo Source: NOAA

The dream of medical science is to be able to grow organs using a patient's own cells. One of the methods envisioned is to inject these cells into an animal fetus. The theory behind this is, as the animal grows, the organs will consist mostly of the patients own cells and should work. Not only that but the chance of rejection should be much less .But is this dream a realistic one, and is it fair to all those animals that would be raised as parts? The dream may be stopped dead in its tracks if animal diseases start to spread in the humans who are transplanted. This might even lead to epidemics of diseases among humans that have not been transplanted since diseases mutate. As far ar raising animals for parts, many would argue that we now raise animals for food so what is the difference? This is a subject that has two sides, each with very strong feelings one way or the other.

Even if we raise animals as parts and this is agreed upon, can we go too far? Mice are now being injected with human brain cells. Will we ultimately create mice that understand? There isn't much chance of this happening but could it happen with the higher animals? What will happen if human brain cells are introduced into the brains of the higher apes? Science is already finding out that they are much smarter than first thought and are capable of sign language in many cases. If we decide to create an ape for parts that has an enhanced brain will this be more like trying to raise cloned humans for parts? This burning question is yet to be answered. Some people would say that this is a ridiculous though, that doctors would never use the organs of the great apes in this way, but there have been 15 operations in the U.S. where they were used but all the operations failed.

Right now there is a worry that certain disorders in pigs, that don't effect the pig but could effect humans might appear. After all, pig parts are transplanted into humans. They routinely receive valves but these are processed and are dead tissue when used. But other pig parts might endanger the recipient. Pigs have a disorder known as porcine endogenous retrovirus and it is part of their DNA. It is not harmful to pigs but causes concern to scientists. They are afraid that if might effect humans. Baboon marrow has also been used to replace the marrow of patients with aids since it is resistant to that disease. It is hoped that this marrow might replace the patient's damaged immune system. Even pig brain cells from fetal tissue have been injected into patients with advanced Parkinson's disease. The idea was that it might produce dopamine since the Parkinson's patients have none.

Pig
Photo Source: USDA

In France a pig's kidney was transplanted into a woman while a goat's liver was put into another woman. The results were tragic. Neither woman survived. The animals that are evolving as the favorites to use in transplants are pigs and yes, baboons. In 1964 a baby was given a baboon heart but it didn't survive. Two years before that a couple of baboon livers were transplanted but again no one survived.

Another method is the temporary transplant. This seems to work better at times. People have been hooked up to animal livers that were kept outside of their body and it has kept them alive long enough for them to receive a human transplant.

Because of the chance of disease when receiving animal transplants or transplants of human cells from animals, it is very important that the recipient be monitored. They will have to under go constant examination to prevent the spread of any disease, but it is better than dying. But will this tax our medical facilities too much? It seems we will either need more medical professionals for this task or computer monitoring that may be beyond our capability today.

There is hope on the horizon in another area, that area is custom cloned animals. Scientists claim that they have cloned pigs without the rejection factor and that the organs of these animals could go right into humans. There are over 75,000 Americans on the transplant list. Most transplants used to come from auto accidents but the amount of fatalities is dropping causing severe shortages in available organs. Another source of organs is desperately needed. The ideal solution would be to grow human tissue with out cloning a human. Human tissue has been grown in the lab. If a method of growing organs in laboratories can be found it might solve the organ shortage.