Fetal Pig Cells

Instead of using human cells, pig cells may work. Research involving treating patients with Parkinson's disease with fetal pig cells has given some patients a new outlook on life even though not all patients benefited. Using xenotransplanted tissues does present a potential problem with tissue rejection. Fortunately, transplanting cells of a tissue does not have as many problems as transplanting whole organs. Further, working in the brain also may help in dealing with tissue rejection.

First of all, rejection is always going to be a problem. The barrier between the brain and the circulatory system is great. Even antibodies circulating through the blood stream can not move past this barrier and target the foreign tissue. However, over a long period of time, killer T cells will find the new tissue and destroy it.

So the next option is to hide the proteins on the cell surface from the killer T cells or remove them. "Masks" have been developed to hide the fetal pig cells from the patient's immune system. While the mask is known to wear off within a few months, these patients have been surviving for over three years with no sign of rejection. The even better news is that the patient does not need immunosuppressive drugs. The researchers speculate that the immune cells are "reeducated" to recognize the fetal pig cells as self. But there is another possibility.

Autopsies of treated patients who died of other causes revealed that new cells had developed in their brain. We now know that there is limited possibility for the brain to regrow some tissue from stem cells.