The results of this study demonstrate 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 co-author and director of the Neuroscience Center at the Feinstein Institute for Medical Research in Manhasset, N.Y. “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 evident at one, two and four years after the transplantation surgery.
The findings reported in this study demonstrate the critical 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.”
According to the National Institute of Neurological Disorder and Stroke, 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 usually affects people over the age of 50. Early symptoms are subtle and occur gradually. In some people, the disease progresses more quickly than in others. Parkinson’s disease is both chronic (meaning that it persists over a long period of time) and progressive (meaning that its symptoms grow worse over time). There is presently no cure; however, a variety of medications provide dramatic relief from the symptoms. Novel surgical interventions such as cell transplantation and gene therapy are currently being investigated for patients with medically refractory symptoms.
Co-authors of “Dopamine Cell Implantation in Parkinson’s Disease: Long-Term Clinical and 18F-FDOPA PET Outcomes” include Yilong Ma, Chengke Tang, David Eidelberg, Vijay Dhawan, Thomas Chaly, Center for Neurosciences, The Feinstein Institute for Medical Research, Manhasset, New York; Yilong Ma, Thomas Chaly, David Eidelberg, Vijay Dhawan, Departments of Neurology and Medicine, North Shore University Hospital and New York University School of Medicine, Manhasset, New York; Paul Greene, Stanley Fahn, Department of Neurology, Columbia College of Physicians and Surgeons, New York, New York; Robert Breeze, Department of Neurosurgery, University of Colorado School of Medicine, Denver, Colorado; and Curt Freed, Neuroscience Center and Division of Clinical Pharmacology and Toxicology, University of Colorado School of Medicine, Denver, Colorado.
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