Q&A: Parkinson's DiseaseMarch 29, 2010 | by Marla Paul
CHICAGO --- Michael J.Fox, a prominent spokesperson in the fight against Parkinson's disease, is an example of a person with young onset of the disease. Yet the reality is that Parkinson's is the second most common chronic neurological disease of aging.
The exciting question being examined at Northwestern University Feinberg School of Medicine: Can a commonly used blood pressure medicine that helps protect against Parkinson's disease in mice have the same effect in humans?
Tanya Simuni, M.D., associate professor of neurology at Northwestern University Feinberg School of Medicine and a physician at Northwestern Memorial Hospital, is leading a national clinical trial to find out.
The trial is based on the research of D. James Surmeier, Nathan Smith Davis Professor and chair of physiology at Feinberg. Surmeier found that isradipine, a drug widely used to treat hypertension, rejuvenates stressed-out dopamine neurons to their vigorous younger selves in animal models of the disease. Parkinson's symptoms are triggered by the loss of dopamine.
As the director of Northwestern's Parkinson's Disease and Movement Disorders Center, Simuni is searching for a cure for this debilitating disease affecting about one million people in the United States. As the population ages, the number of people living with Parkinson's is expected to double within the next 10 to 20 years.
Marla Paul spoke recently with Simuni about Parkinson's disease and her research.
What is Parkinson's disease?
Parkinson's is the second-most common chronic neurological disease of aging. Its symptoms are slowness of movements, gait and balance problems. It also may include a variety of nonphysical symptoms.
What are its nonphysical symptoms?
Depression is very common. So is cognitive impairment with advanced stages, sleep dysfunction and excessive daytime sleepiness. People also may have problems with low blood pressure, overly frequent urination and constipation.
You describe it as a disease of aging, but one of the primary spokespeople of the disease is the actor Michael J. Fox. How often does Parkinson's affect younger people?
>While the typical age of onset of Parkinson's is considered to be late 50s and early 60s, about 10 percent of patients start having symptoms in their 40s or even younger. Obviously Michael J. Fox is an example of a person with young onset of this disease. We are now finding that a number of them might have genetic predisposition to the disease being responsible for the young onset.
What causes Parkinson''s?
We don't know. We do know that the symptoms of the disease are triggered by loss of dopamine, the chemical that is responsible for coordination of movements. The two leading hypotheses are a combination of some environmental exposure and potential genetic causes. Overall, Parkinson's is not a hereditary disease. More than 95 percent of people will not have a family history of the disease.
What are some common treatments?
We are very skillful in treating the symptoms of the disease, but we don't have a cure. The majority of therapy is aimed at restoring the level of dopamine, the chemical that is deficient in the brain. It is very effective, especially early in the course of the disease, but it can be associated with immediate and longer-term side effects. As the disease progresses, patients start experiencing involuntary movements known as dyskinesia. Then they may need surgical intervention for Parkinson's disease, which is done with brain stimulation in most cases."
Where is the focus in research right now?
Ultimately, the goal is to find a cure. We're not there yet, but we are trying to identify treatments that slow the progression of the disease. We call that neuroprotective therapy and that's the most active area of research in Parkinson's. A number of agents have been tried, but unfortunately there is no drug yet that has a proven benefit in Parkinson's.
Tell us about your research.
At Northwestern, we're excited to be testing isradipine, a medication approved by the Food and Drug Administration for the treatment of high blood pressure. Isradipine was previously shown to prevent the development of parkinsonism in animal models. We are conducting a study to determine the safety and tolerability of isradipine, and obtain pilot data on potential effective doses for slowing the progression of Parkinson's disease in humans. I am the lead investigator of this national study with 17 sites, including Chicago. Dr. Cindy Zadikoff is the local investigator at Northwestern.
Who can participate in the study?
The study is recruiting individuals with Parkinson's disease diagnosed within the past three years. The patients have to be 30 years old or older at the time of diagnosis and not taking any major Parkinson's medications. Patients who are interested and willing to participate in the study can learn more about the study by calling (888) 887-3774. The local number is (312) 503-2593."