In recent years, research on Parkinson's has advanced to the point that halting the progression of the disease, restoring lost function, and even preventing the disease are all considered realistic goals. While the goal of preventing Parkinson's disease may take years to achieve, researchers are making great progress in understanding and treating it.
One of the most exciting areas of Parkinson's research is genetics. Studying the genes responsible for inherited cases can help researchers understand both inherited and sporadic cases of the disease. Identifying gene defects can also help researchers
- understand how Parkinson's occurs
- develop animal models that accurately mimic the death of nerve cells in humans
- identify new approaches to drug therapy
- improve diagnosis.
Researchers funded by the National Institute of Neurological Disorders and Stroke are gathering information and DNA samples from hundreds of families with members who have Parkinson's and are conducting large-scale studies to identify gene variants that are associated with increased risk of developing the disease. They are also comparing genetic changes in Parkinson's with those in similar parkinsonian diseases such as progressive supranuclear palsy, and other neurodegenerative disorders such as Alzheimer’s disease.
In addition to identifying new genes for Parkinson's disease, researchers are trying to learn about the function of genes known to be associated with the disease, and about how gene mutations cause disease.
Effects of Environmental Toxins
Risk factors such as repeated occupational exposure to certain pesticides and chemical solvents may influence who develops Parkinson’s disease. NIH-funded studies, including those at NINDS and the National Institute of Environmental Health Sciences (NIEHS) are examining these factors in model systems as well as in epidemiological studies of humans. One NINDS study will examine blood samples and clinical data from volunteers to learn how changes in biological metabolites and clinical Parkinson’s disease measures may be linked to risk factors and environmental exposures, including smoking and coffee consumption.
Role of Lewy Bodies
Other studies focus on how Lewy bodies form and what role they play in Parkinson's disease. Some studies suggest that Lewy bodies are a byproduct of a breakdown that occurs within nerve cells, while others indicate that Lewy bodies are protective, helping neurons "lock away" abnormal molecules that might otherwise be harmful.
Biomarkers for Parkinson's—measurable characteristics that can reveal whether the disease is developing or progressing—are another focus of research. Such biomarkers could help doctors detect the disease before symptoms appear and improve diagnosis of the disease. They also would show if medications and other types of therapy have a positive or negative effect on the course of the disease. The National Institute of Neurological Disorders and Stroke has developed a research network, the Parkinson’s Disease Biomarkers Program (PDBP), designed specifically to address these questions and to discover and validate biomarkers for Parkinson’s disease.
NINDS has been a pioneer in the study and development of deep brain stimulation, or DBS. As stated in the “Treatment” section, DBS is an important treatment option for some people living with Parkinson’s disease whose symptoms no longer respond to PD medications. NINDS research continues to fine-tune the procedure and to develop improved DBS electrodes to help even more people with Parkinson’s disease regain function. NINDS-supported researchers are also conducting studies to better understand the therapeutic effect of DBS on neural circuitry and brain regions affected in Parkinson’s disease. Other NINDS-funded researchers are studying different forms of brain stimulation (such as transcranial magnetic stimulation) on different parts of the brain to better understand how to treat conditions such as Parkinson’s disease.
Parkinson’s disease clinical studies offer an opportunity to help researchers find better ways to safely detect, treat, or prevent Parkinson’s disease. NINDS conducts clinical studies on Parkinson’s disease at the NIH research campus in Bethesda, Maryland, and supports Parkinson’s disease studies at medical research centers throughout the United States. But studies can be completed only if people volunteer to participate. By participating in a clinical study, healthy individuals and people living with Parkinson’s disease can greatly benefit the lives of those affected by this disorder.
Current studies include genetics and Parkinson’s disease, search for Parkinson’s disease biomarkers, experimental therapies and other treatment options, diagnostic imaging, brain control and movement disorders, DBS, and exercise and Parkinson’s disease. For more information about NINDS clinical trials on Parkinson’s disease, see www.clinicaltrials.gov and search for “Parkinson AND NINDS.”
(Watch the video to learn more about clinical trials in Parkinson's disease. To enlarge the video, click the brackets in the lower right-hand corner. To reduce the video, press the Escape (Esc) button on your keyboard.)
Another type of cell therapy involves stem cells. Some stem cells derived from embryos can develop into any kind of cell in the body, while others, called progenitor cells, are less flexible.
Scientists are exploring various types of stem cells, including induced pluripotent stem cells (iPSCs), as opportunities for Parkinson’s disease drug discovery. iPSC technology is used to define disease mechanisms and discover the most promising treatments for sporadic Parkinson’s disease. To pursue this area of research, NINDS established a Parkinson’s disease cell research consortium in 2009 in collaboration with the Michael J. Fox Foundation and the Parkinson’s Disease Foundation.
NINDS supports extensive research aimed at protecting nerve cells from the damage caused by Parkinson’s disease. NINDS-funded research continues to reveal neuroprotective strategies to improve the lives of people with Parkinson’s disease. Laboratory data showed the drug isradipine (which is used to treat high blood pressure) may slow the development of parkinson’s-like symptoms in animal models of the disease. The drug, which may block damage caused by certain chemicals that flow through special channels in brain cells that make dopamine, is now being studied in a NINDS-funded clinical trial called STEADY-PD3.
Other studies focus on “antioxidant” approaches, which seek to protect brain cells from potential damage. Recent research has shown that higher levels of the antioxidant urate may be neuroprotective in animal models, and possibly reduce risk for and slow progression of Parkinson’s disease in people. NINDS is supporting a new clinical trial to test whether inosine, a compound which is naturally converted to urate in the human body, can slow the progression of Parkinson’s disease and improve other symptoms.
An ongoing early phase NIH clinical trial will assess the safety, tolerability, and potential clinical effects of gene therapy with Glial Cell Line-Derived Neurotrophic Factor (GDNF). GDNF is a protein that may help protect dopamine-producing nerve cells that are damaged in Parkinson’s disease. This trial is for individuals with advanced Parkinson’s disease. It is based on NINDS-sponsored research showing that an advanced technique for delivery of the GDNF gene into the brain improves the health and function of the dopamine neurons in animal models of Parkinson’s disease.
The National Institute of Neurological Disorders and Stroke also supports the Morris K. Udall Centers of Excellence for Parkinson's Disease Research program. NINDS funds 9 Udall Centers, located across the USA. The Centers which study cellular mechanisms underlying Parkinson’s disease, identify and characterize disease-associated genes, and discover and develop potential therapeutic targets. The Centers' multidisciplinary research environment allows scientists to take advantage of new discoveries in the basic, translational, and clinical sciences that could lead to clinical advances for Parkinson’s disease. To learn more, visit the NINDS Udall Centers.