An INVESTIGATIONAL TREATMENT in which DOPAMINE-producing brain cells taken from aborted human fetuses are transplanted into the brain of a person with Parkinson’s disease. Once the fetal cells “take,” they grow and reproduce, eventually restoring enough dopaminergic neurons to replace those lost to Parkinson’s disease. This treatment is highly controversial for ethical reasons; some people consider it inappropriate to use cells and tissue that result from abortions. In this procedure, the donor cells are extracted from fetal brain tissue, prepared in a solution, and injected into a catheter that is carefully threaded into the striatum and substantia nigra of the person with Parkinson’s. This procedure “seeds” this area of the brain that is essential to movement with cells that will readily infiltrate the brain and begin producing dopamine. Although the first fetal dopaminergic brain cell transplants were done in Sweden in 1987, this procedure remains highly experimental. The number of patients who have received transplants is small, and the results so far have ranged from amazing to disappointing. This inconsistency is one reason the procedure remains experimental. Some people have experienced 10 or more years without any symptoms of Parkinson’s and have apparently normal dopaminergic function, as measured by imaging techniques such as single photon emission COMPUTED TOMOGRAPHY (SPECT) or MAGNETIC RESONANCE imaging (MRI) within the striatum and substantia nigra. In other people the transplanted cells did not seed and grow, providing little to no relief of symptoms.
In two large well-designed studies in the United States, the vast majority of patients did not benefit from the surgery, though a few did benefit. As for the complication of “run away” dyskinesias, though these abnormal involuntary fidgety movements commonly develop as a side effect of peaking levodopa levels in people with longstanding Parkinson’s, roughly one in six people who had the surgery had these movements all the waking day, even when they were off of all anti-parkinson’s medications. Such results have led to a virtual moratorium on fetal cell transplantation studies in humans in the United States.
The procedure’s controversial nature further limits research studies, particularly in the United States where abortion and a fetus’s “right to life” are hotly debated; with current techniques, the procedure requires roughly four aborted fetuses to provide the cells necessary for one transplant. Researchers differ in their views of the viability of fetal dopaminergic brain cell transplants for treating Parkinson’s; even among those who support research in this area, many believe there are more effective ways to obtain the same result. One such method is fetal porcine brain cell transplant, in which the dopaminergic brain cells are taken from pig embryos. Porcine tissue is closely related to human tissue and is already used in other transplant applications such as growth of heart valves.