Parkinson’s Brain Shot
Parkinson’s disease is a condition that affects movement. It occurs when nerve cells in an area of the brain called the substantia nigra, degenerate or die. These cells normally produce dopamine, a brain chemical involved in the transmission of messages controlling movement. As these nerve cells die, movement becomes impaired. Most patients lose 60 to 80 percent of their dopamine-producing cells before symptoms become apparent.
There are four characteristic signs of Parkinson’s: tremor, bradykinesia (slowed movement), rigidity (stiffness) and postural instability (balance problems). Resting tremor is a common initial sign. It usually involves the thumb or wrist and tends to initially occur on one side. Gradually the symptoms spread to the other side of the body and may involve the legs, jaw or tongue. Bradykinesia is a slowing of spontaneous movement (like getting out of a chair or lifting a leg to walk). It is the most disabling symptom of Parkinson’s, affecting the patient’s ability to perform simple, routine tasks. Rigidity occurs when signals are disrupted between opposing muscle groups. Normally, when one muscle contracts, an opposing muscle relaxes. Loss of coordinated muscle signaling causes both sets of muscles to stay contracted and stiff, leading to short, jerky movements. Postural instability, or difficulty maintaining balance, is typically the last major symptom to appear. Patients may fall and often develop drooped shoulders and a stooped posture.
The National Parkinson Foundation estimates about 1.5 million Americans have Parkinson’s disease. About 60,000 new cases occur each year. Risk increases with age. Most patients are diagnosed after 60. Roughly 10 percent develop symptoms before 45. In most cases, the cause isn’t known. However, younger patients may carry a genetic mutation that puts them at risk for early onset for the disease.
Treating Parkinson’s
There is no cure for Parkinson’s disease. Medications can help reduce some symptoms. Some patients may also benefit from deep brain stimulation, pallidotomy (destruction of the globus pallidus portion of the brain) or thalamotomy (destruction of the thalamus).
Once nerve cells in the brain die, they can’t be restored. Researchers are now looking for ways to help damaged cells recover and/or protect healthy cells from degeneration. One treatment under study is CERE-120. CERE-120 contains a gene responsible for the production of neurturin, a naturally occurring protein which has been shown to support dopamine-producing nerve cells and protect them from injury. A common virus (adenovirus) carries the gene into the body.
Intravenous infusion and injections of neurturin don’t work because not enough of the product reaches the area of the brain where it’s needed. So, doctors place it directly into the brain. A small hole is drilled through the skull on one side of the head. A cannula is inserted into the brain and the CERE-120 is injected into the putaminal region. The procedure is then repeated on the other side.
In the phase I trial, patients who received CERE-120 experienced a 36 percent improvement in Parkinson’s symptoms within six to nine months of treatment. The effects were sustained for at least one year.
CERE-120 is currently in a phase II, double-blind trial with 51 patients; 2/3 of the participants will receive the active treatment and 1/3 will receive a sham treatment (i.e., hole drilling only, no injection). The study is no longer looking for participants. For more information, log onto http://www.clinicaltrials.gov. Then type the trial identification number in the search box: NCT00400634. A list of study sites follows:
Study sites for CERE-120:
University of Alabama, Birmingham
University of California, San Francisco
Rush University Medical Center, Chicago
Mount Sinai School of Medicine, New York City
Duke University Medical Center, Durham, NC
Cleveland Clinic, Cleveland, OH
Oregon Health and Science University, Portland, OR
Pennsylvania Hospital, Philadelphia
Baylor College of Medicine, Houston
The study is still ongoing, but no longer accepting new participants. For information, log onto http://www.clinicaltrials.gov. Then type the trial identification number in the search box: NCT00400634.
For information about other Parkinson’s Disease trials: PDtrials, http://www.pdtrials.org
For general information on Parkinson’s Disease:
The Michael J. Fox Foundation for Parkinson’s Research
National Institute of Neurological Disorders and Stroke
National Parkinson Foundation
Parkinson’s Disease Foundation
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