A controversial fetal cell experiment produced 鈥渄evastating鈥� results in five patients because some replacement cells were transplanted into areas that did not need them, according to the researchers who ran the experiment.
Fetal cells were transplanted into the brains of 20 Parkinson鈥檚 disease sufferers. In five, this caused an over-production of dopamine and excessive jerky movements characteristic of the disease itself.
The initial results of the study, led by Curt Freed of Columbia University, New York were published in the New England Journal of Medicine earlier in 2001. At the time, Paul Greene, another of the researchers, described the side-effects in the five patients as 鈥渁bsolutely devastating鈥�.
Advertisement
He called for all trials of fetal transplants to treat Parkinson鈥檚 to return to the drawing board. However, previous transplantation trials in Europe had relieved symptoms in many patients without producing severe side effects.
Signal problem
Parkinson鈥檚 disease is caused by a loss of dopamine-producing cells in the substantia nigra. This loss means another part of the brain, the putamen, no longer receives the dopamine that prompts it to send out signals controlling movement.
So Freed鈥檚 team transplanted the fetal cells into the putamen. However, a review of brain scans of the patients made before and up to two years after surgery has now revealed that all five suffering adverse reactions had relatively undamaged dopamine function in the left part of the putamen.
鈥淲e have learned that it is possible to place grafts in places where they can cause mischief,鈥� says David Eidelberg of North Shore-Long Island Jewish Research Institute in New York, who conducted fMRI brain imaging of the patients during the study.
鈥淚n the future, transplants for advanced Parkinson鈥檚 disease will need to be specifically targeted to areas of the putamen that really need improvement in dopamine function,鈥� he says.
The new research was presented at the Society for Neuroscience annual conference in San Diego.