Have hopes for stem cell therapy been raised too high?
The available evidence indicates that loss of dopamine-producing neurons which produces some of the symptoms of Parkinsons is only one of many kinds of brain damage caused by the disease. In fact, the brain’s dopamine-producing neurons are affected only later in the course of the disease. And some of the disabilities seen in Parkinsons do not even involve dopamine deficiencies. Accordingly, as the author of one recent evidence review observed, We have reached the point of diminishing therapeutic returns with drugs acting on dopamine systems … (Ahlskog JE 2007) And these findings led him to sound a pessimistic note concerning the hope that transplanted dopamine-producing neurons produced by stem cell research could prove curative: the benefits from transplantation surgeries aimed at restoring dopaminergic neurotransmission [by implantation of healthy neurons] will be limited … (Ahlskog JE 2007) As with other diseases, the greatest benefits may flow from discovering any environmental
