PET Vital in Helping Parkinson's Research

A large-scale study conducted to gauge the effectiveness of dopamine cell transplantation in Parkinson's disease patients has shown significant improvements in motor skills and brain function.

Reported in the January 2010 issue of the Journal of Nuclear Medicine (JNM), the study's findings demonstrated that transplanted cells were viable and integrated well with the host brain tissue. Furthermore, these cells produced dopamine that helped support the brain and led to an improvement in motor symptoms. These improvements were sustained over a four-year study period.

"This study provided new insights into the time course of transplantation outcome,” said David Eidelberg, M.D., study coauthor and director of the Neuroscience Center at the Feinstein Institute for Medical Research (Manhasset, NY, USA). "Comprehensive long-term clinical follow-up, together with molecular imaging, allows for a more realistic appraisal of this kind of intervention for Parkinson's disease.”

Researchers reported long-term clinical and imaging outcomes after transplantation from 33 patients who originally participated in a one-year, double-blind, placebo-controlled trial of embryonic dopaminergic cell implantation for Parkinson's disease. Clinical improvement in motor ratings, as well as increased brain uptake of 18F-fluorodopa (18F-FDOPA), the radiotracer that is widely used to investigate the function of dopamine grafts, was seen at one, two and four years after the transplantation surgery.

The findings reported in this study demonstrate the vital roles played by positron emission tomography (PET) --a noninvasive molecular imaging technique--in screening patients for transplantation procedures and in objectively assessing graft survival over the long term. "This work provides a valuable template for conducting imaging-based trials of cell transplantation for Parkinson's disease and perhaps other neurodegenerative disorders,” said Yilong Ma, Ph.D., lead author of the JNM study and associate investigator at the Feinstein Institute for Medical Research. "It offers guidance in the design of this type of trial, particularly with respect to the use of quantitative imaging as an adjunct to clinical assessments.”

Parkinson's disease belongs to a group of conditions called motor system disorders, which are the result of the loss of dopamine-producing brain cells. The four primary symptoms are tremor--or trembling in hands, arms, legs, jaw, and face; rigidity--stiffness of the limbs and trunk; bradykinesia--slowness of movement; and/or postural instability--impaired balance and coordination.

Parkinson's disease typically affects people over the age of 50. Early symptoms are subtle and occur gradually. There is presently no cure; however, a variety of medications provide dramatic relief from the symptoms. Innovative surgical interventions such as cell transplantation and gene therapy are currently being evaluated for patients with medically refractory symptoms.

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Feinstein Institute for Medical Research