An interview with Story C. Landis
What are the risk factors for developing Parkinson's?
The clearest risk factor is age. In addition, researchers have identified a number of genes that cause or contribute to Parkinson's disease (PD), as well as potential environmental risk factors. A primary piece of evidence that environmental factors play a role is that the relative risk of PD is higher in industrialized countries. Farmers and other agricultural workers also have an increased risk of developing PD, suggesting that exposure to toxic chemicals or other environmental factors present in industrial and agricultural areas might increase the risk of PD. In some studies, coffee drinking has been inversely associated with PD, but the evidence is uncertain, and combining coffee and hormone therapy may actually increase women's risk for developing PD. Smokers have a lower rate of PD—about 50 percent less—than nonsmokers, but the relationship between smoking and Parkinson's disease is not clear. Contrary to popular belief, minor head injury does not cause Parkinson's disease. A new study indicates that exercise may lower PD risk.
What is the most promising area of current research?
There are a lot of promising areas in PD research, but one of the most exciting is genetics. Researchers have identified a number of genes and chromosomal regions believed to play a role in PD. Studying the gene mutations responsible for inherited cases can help researchers understand both inherited and sporadic types of the disease. Identifying gene defects may be able to help researchers develop animal models that accurately mimic the neuronal death in human PD, identify new drug targets and improve diagnosis. Based on genetic findings, investigators have already developed improved animal models, so essential for our understanding of what causes the disease and for testing new treatments, and have made breakthroughs in cell biology that are helping to elucidate the various neurodegenerative processes and mechanisms in PD. In the future, it may become possible to test for individual gene differences in order to customize treatment of individual PD patients.
And these basic research successes are translating into the clinic: We now have a number of new and exciting therapeutic strategies at or near the point of clinical testing. These include neuroprotection using various medications, other substances, or nerve growth (neurotrophic) factors and gene therapy. Other potential therapies still being tested in animals include a vaccine to modify the immune system in a way that can protect dopamine-producing neurons, stem cell therapy and inhibition of inflammatory enzymes, including COX-2.
How close are we to developing a cure?
It is not possible to predict a precise time line for major breakthroughs or a cure for PD—even in this time of great scientific progress. But we are initiating clinical trials that we believe will be critical to improving the treatment and quality of life of individuals with PD, developing a framework so that basic research can be effectively translated into treatments, and continuing to invest in essential basic research—the foundation for progress in medical science.