News — A team of researchers have identified elevated serum levels of the pesticide β-hexachlorocyclohexane (β-HCH) in patients with Parkinson's disease, indicating that exposure to a specific pesticide may contribute to the development of the disease. The study, published today in Archives of Neurology, is a collaboration of research teams led by Jason R. Richardson, PhD, assistant professor of environmental and occupational medicine at UMDNJ-Robert Wood Johnson Medical School and resident member of the Environmental and Occupational Health Sciences Institute, a joint institute of Robert Wood Johnson Medical School and Rutgers University, and Dwight C. German, PhD, professor of psychiatry at the University of Texas Southwestern Medical Center, Dallas, TX.
β-HCH is an insecticide that was used widely in the United States from the 1950s through the 1970s in agriculture. β-HCH also is found as a contaminant of the insecticide lindane, which was used in treatments for fleas and ticks in pets and in treatments for lice and mange in humans until recently. Although its use was banned in the 1970's, β-HCH is still found as a persistent environmental contaminant in water and soil.
"Previous studies established the link between pesticides and neurodegenerative diseases, but most had not identified specific pesticides that may be associated with an increased risk of developing Parkinson's," said Dr. Richardson. "This discovery provides a foundation upon which to research the precise implications of β-HCH's role in the cause of the disease and how β-HCH's levels may be affected by other possible factors such as genetic disposition and lifestyle choices."
In the study, the researchers measured the levels of 16 pesticides in blood samples from patients with Parkinson's or Alzheimer's disease and a control group with no neurological disease. The researchers detected β-HCH in 76 percent of the patients with Parkinson's, 40 percent of the control patients and 30 percent of the patients with Alzheimer's. In addition to being more frequently detected in Parkinson's patients, the amount of β-HCH in the serum of Parkinson's patients was much higher than in the controls. The study indicated that there was no significant difference in the levels of the other 15 pesticides measured among the study participants.
According to the researchers, detection of β-HCH in the serum of the control group, although at a lower level, suggests that other factors may interact with β-HCH to increase the risk of Parkinson's. Moving forward, the researchers plan to expand the study population and work to understand if there is a correlation between β-HCH serum levels and other possible risk factors including, but not limited to, genetics, diet or gender.
"We hope additional research will not only help identify people who may be at risk before symptoms of the disease appears, enabling earlier detection of the disease, but also advance the development of therapies to slow or prevent neurodegeneration caused by Parkinson's," said Dr. Richardson.
Contributing researchers on the study include the following resident members at the Environmental and Occupational Health Sciences Institute: Stuart L. Shalat, ScD, associate professor of environmental and occupational medicine at Robert Wood Johnson Medical School; and Brian Buckley, PhD, executive director of laboratories and Bozena Winnik, PhD, research analyst, both of Rutgers University. Contributing researchers at the University of Texas Southwestern Medical Center are Padraig O'Suilleabhain, MD, associate professor and Ramón Diaz-ArrastÃÂa, MD, PhD, professor, both in the department of neurology; and Joan Reisch, PhD, professor of clinical sciences.
The research was supported by grants from the National Institute of Environmental Health Sciences, the National Institute of Aging, the Dallas Area Parkinsonism Society, the Dallas Foundation and the Michael J. Fox Foundation for Parkinson's Research. Study participants were patients at the Clinical Center for Movement Disorders and the Alzheimer Disease Center, both at the University of Texas Southwestern Medical Center. Analysis of the samples was conducted at the Environmental and Occupational Health Sciences Institute, a joint institute of UMDNJ-Robert Wood Johnson Medical School and Rutgers, The State University of New Jersey.
UMDNJ-ROBERT WOOD JOHNSON MEDICAL SCHOOL
As one of the nation's leading comprehensive medical schools, Robert Wood Johnson Medical School of the University of Medicine and Dentistry of New Jersey is dedicated to the pursuit of excellence in education, research, health care delivery, and the promotion of community health. In cooperation with Robert Wood Johnson University Hospital, the medical school's principal affiliate, they comprise New Jersey's premier academic medical center. In addition, Robert Wood Johnson Medical School has 34 hospital affiliates and ambulatory care sites throughout the region.
As one of the eight schools of the University of Medicine and Dentistry of New Jersey with 2,800 full-time and volunteer faculty, Robert Wood Johnson Medical School encompasses 22 basic science and clinical departments and hosts centers and institutes including The Cancer Institute of New Jersey, the Child Health Institute of New Jersey, the Center for Advanced Biotechnology and Medicine, the Environmental and Occupational Health Sciences Institute, and the Stem Cell Institute of New Jersey. The medical school maintains educational programs at the undergraduate, graduate and postgraduate levels for more than 1,500 students on its campuses in New Brunswick, Piscataway, and Camden, and provides continuing education courses for health care professionals and community education programs.
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