Parkinson's Research & Studies
Although the incidence of Parkinson's disease has remained relatively consistent in recent years, patients today often have access to more treatment options. Important areas of research include ongoing studies to learn more about genetic and environmental causes for the disease and clinical trials to develop new treatments for primary symptoms (e.g., slow movements, tremors, unsteady gait) and secondary symptoms (e.g., psychosocial issues, depression, anxiety, decreased mental function).
The National Institutes of Health (NIH) is working with other organizations, such as the Parkinson's Institute and Clinical Center, the American Parkinson Disease Association, and the Michael J. Fox Foundation for Parkinson's Research, to establish registries for patients who have Parkinson's disease. These regional and statewide registries may provide important information about potential triggers, risk factors, and causes for Parkinson's disease, and possibly lead to a cure.
According to the NIH, six genes and several substances that attack nerve cells (neurotoxins) that are associated with Parkinson's disease had been identified as of January 2008. A number of ongoing studies are focused on further examining the link between Parkinson's disease and environmental factors, such as exposure to pesticides (substances used to kill insects that damage plants and crops) and other chemicals.
Genetic testing may provide important information about hereditary risk factors for Parkinson's disease and help identify the cellular process that causes the condition. By studying the role of genes in Parkinson's disease, physicians may be able to determine who is at increased risk for developing Parkinson's and provide earlier treatment. Information from genetic studies also may lead to the development of new treatment plans.
Some of these studies involve ribonucleic acid (RNA), which is a substance in cells that controls protein synthesis (i.e., the combining of proteins within cells) and may play a role in the development of Parkinson's disease. Scientists are trying to determine if it is possible to interfere with gene expression and "silence" RNA by inserting a substance called silencing RNA (sRNA; also called interfering RNA) into the brain. RNA-targeted silencing technology may be used to treat Parkinson's disease and other neurological conditions (e.g., Huntington's disease, dystonia).
Treatments that are currently being investigated include stem cell therapy, gene therapy, and new medications to protect nerve cells (neurons) from damage and slow progression of the disease. In stem cell research, undeveloped cells found in bone marrow and lymphatic tissues (called stem cells or hemocytoblasts) are used to reconstitute damaged brain cells (e.g., neurons).
Stem cell research is somewhat controversial. Stem cells may be obtained from discarded blood in a newborn's umbilical cord, from adult bone marrow, or from an aborted embryo. Recent research has shown that skin cells may be able to take on characteristics of embryonic stem cells (i.e., cells taken from human embryos), which may reduce the controversy surrounding this experimental treatment and help to advance stem cell research further.
Gene therapy involves loading safe viruses containing important genetic information and/or growth enzymes directly into targeted areas of the brain to rejuvenate damaged cells.
Clinical trials involve using substances that affect cell function (e.g., creatine, coenzyme Q10 [CoQ10], GM-1 ganglioside, minocycline) to help protect and restore nerve cells. Other trials involve targeting deep brain stimulation (DBS) to specific areas of the brain that thought to be involved in Parkinson's disease development (e.g., the paramedian nucleus [PPN] in the brainstem). Targeting this area may improve walking and balance in patients who have Parkinson's.
New deep brain stimulation (DBS) devices are also being developed. DBS targets the subthalamic nucleus, the globus pallidus, or the thalamus in the brain. In DBS, an implanted electrode is used to inactivate, not destroy, the targeted area. The electrode is connected to the brain via a wire that runs beneath the patient's skin to a stimulator and battery pack in the patient's chest. Deep brain stimulation is a reversible treatment that allows for precise control of symptoms.
In patients who have Parkinson's disease, oral medications (e.g., levodopa, carbidopa, dopamine agonists) often are absorbed slowly in the stomach, reducing the effectiveness of the drug. New drug delivery methods are being developed to prevent decreased absorption and improve the medications' effectiveness.
These delivery methods include transdermal patches (which are worn on the skin and allow medication to be continuously absorbed), subcutaneous (beneath the skin) injections, and intraduodenal infusions (which involve introducing medication directly into the upper portion of the small intestine [duodenum]). New combinations of medications and the use of medications already approved to treat other conditions also are being studied.
Additional Parkinson's disease research is focused on developing new types of treatments to reduce symptoms of the condition. These treatments include a device to help relieve the "masked face" associated with Parkinson's, exercise and weight training programs, and physical and occupational therapy.
Current studies show that patients who have Parkinson's disease often benefit from treatment provided by a health care team that includes a number of different medical providers (called multi-disciplinary care). This medical team may include geriatric specialists, neurologists, neurosurgeons, psychologists, and speech-language pathologists.