In a recent study, neurosurgeons have discovered that adult neural stem cells taken directly from a patient's own tissue can aid in the treatment of Parkinson's disease.

The study, "Autologous Transplantation of Adult Human Neural Stem Cells and Differentiated Dopaminergic Neurons for Parkinson's Disease: A One Year Post-Operative Clinical Outcome," which was presented by Michel F. Lévesque, MD, FRSC, and Toomas Neuman, PhD, on the 70th Annual Meeting of the American Association of Neurological Surgeons (AANS), on Monday, April 8, 2002.

Harvey Cushing Society, the American Association of Neurological Surgeons is a scientific and educational association with nearly 5,500 members worldwide. The AANS is dedicated to advancing the specialty of neurological surgery in order to provide the highest quality of neurosurgical care to the public. All active members of the AANS are certified by the American Board of Neurological Surgery.

The study tracks the authors' methodology of isolating adult neural stem cells, expanding them in vitro (outside the living body), inducing them to differentiate into dopamine-secreting neurons, and selectively delivering them back to targets within the patients. This is accomplished all without the patient experiencing immunosuppression (failure of natural immune responses).

"Previous animal studies have already indicated that transplantation of neural stem cells and stem cell-derived neurons not only reverses the effects of dopaminergic cell loss in the Parkinson's disease rat, but also reveals evidence of long-term survival," said Michel F. Lévesque, MD, an author of the study and AANS member. "Neural transplantation for Parkinson's disease focuses on replacing the loss of essential neurons."

The recent study followed a 57-year old, right-handed patient who was diagnosed with idiopathic (from an unknown cause) Parkinson's disease at age 46. He first received medical therapy with dopaminergic agents, showing initial improvement of his symptoms of rigidity, bradykinesia (extreme slowness of movements and reflexes) and tremor.

However, as the patient's symptoms worsened, the researchers worked with the patient to control his severely disabling tremor. A single stereotactic craniotomy (burr hole) was performed while the patient remained awake. During this procedure, the patient's stem cells were isolated and then expanded in vitro over the course of several months. The patient was then continued on his medication and sent home two days after surgery.

The patient then entered into the clinical study for autologous neural stem cell transplantation for idiopathic Parkinson's disease. Post-operative clinical assessments were performed at 3, 6, 9 and 12 months by "blinded" neurological examinations (the evaluators were unaware of the transplantation).

Post-transplantation studies at three months and 12 months, with the patient off and on medication, were undertaken. At that time, researchers tracked the patient's motor scores. At three months post-operatively and while on medication, the patient's motor scores improved by 37 percent, and other studies reflected a 55.6 percent increase in dopamine uptake. At one year post-operatively, the patient's overall Unified Parkinson's Disease Rating Scale (UPDRS) improved by 81 percent, while on medication and 83 percent while off medication.

"One of the most significant findings of this study was the patient's combined clinical improvement over time," said author Michel Lévesque, MD. "After six months of the transplantation culture in vitro, the number of neural stem cells exceeded several millions."

Autologous neuronal transplantation has numerous advantages as a treatment for Parkinson's disease. This approach eliminates immune reactions at the site of implantation and improves the likelihood of survival of grafted (surgically implanted) cells. It also minimizes risks of transmission of infectious disease, and does not require immunosuppressants or steroids.

In summary, the study revealed that adult neural stem cells harvested from a patient's own tissue can become a source of dopamine neurons. The treatment is extremely useful treatment for Parkinson's disease, with the patient experiencing regression of motor symptoms. "This form of treatment has the potential for making neural stem cell therapy acceptable and available to a large number of patients," added Lévesque.