Archived News


November 1, 2001

Dr. Isaac Pessah, Director
(SACRAMENTO, Calif.) --The UC Davis M.I.N.D. Institute, Schools of Medicine and Veterinary Medicine, and the College of Agriculture and Environmental Science will jointly establish a research center that will, for the first time, study the possible role that environmental contaminants such as pesticides, polychlorinated biphenyls (pcbs) and heavy metals, play in the development of autism.

The UC Davis Center for Children's Environmental Health and Disease Prevention Research is being created under a $5 million, five-year grant from the National Institute of Environmental Health Sciences. The M.I.N.D. Institute and UC Davis are providing another $4 million in funds over the next five years.

"A child's nervous and immune systems undergo immense remodeling during the first two years of life," said Isaac Pessah, professor of molecular biosciences at the UC Davis School of Veterinary Medicine and principal investigator for the new research center. "Environmental exposure to mercury, pesticides and other contaminants during early childhood development could easily alter the normal function of a child's systems. If we find they do, we can then develop rational strategies for treatment and we can work towards preventing exposure to those poisons."

David G. Amaral, a neuroscientist in the School of Medicine who specializes in the study of brain function in autism and is co-principal investigator of the center agrees. "This center is possible due to the unique expertise and resources located at UC Davis. The center's faculty includes eminent researchers in the areas of environmental toxicology, neurodevelopmental disorders, immunology, epidemiology and Superfund initiatives. We have a rapidly growing clinic and autism database at the M.I.N.D. Institute and extensive capabilities on campus in foreign-substance analysis in the blood, cell and molecular biomarker research and animal modeling. This multidisciplinary collaboration will be the catalyst for generating answers about what does and what doesn't cause autism," Amaral said.

The NIEHS grant marks the eighth such center in the United States but the first to specifically look at severe impairments of social behavior as a casualty of ubiquitous pesticides, pcbs and mercury in the environment. The center will conduct the first-ever environmental epidemiological case-controlled study of 2,000 children and launch research projects on the molecular and immunological mechanisms underlying neurodevelopmental disorders and on the influence neurotoxins may have on children's health and social behavior.

With the nation having significantly addressed the problems with lead exposure, NIEHS Director Kenneth Olden said, "we want to see what other environmental substances might trigger developmental problems so that we can reduce the exposures and prevent the damage."

Autism is a neurodevelopmental disorder characterized by social impairment, language deficit and repetitive behavior. To date, autism research has largely been focused on finding the gene or genes that cause the disorder or make some children more susceptible. Suspicion is growing among researchers and parents that a child's contact with environmental chemicals, whether mercury in vaccinations and food, or pesticides on the ground, provides the final push for individuals genetically predisposed for autism.

"We know that there is a genetic susceptibility to autism, but many genes, perhaps 10 to 20, appear to be involved," said Amaral, who is also research director at the M.I.N.D. Institute. "However, there is also substantial suspicion that a 'second hit' is necessary for children to develop full-blown autism. There has been some suggestion that an environmental toxin such as mercury could push a child's developing nervous system over the edge into autism."

The first project the center will undertake is a comprehensive environmental epidemiological study of 2,000 California children between 2 and 5 years of age. The study group will include 600 normal children, 700 children with mental retardation but without autism, and 700 children with autism but not mental retardation. Environmental epidemiologist Irva Hertz-Picciotto, recently recruited to UC Davis School of Medicine from the University of North Carolina at Chapel Hill, will lead this project.

Clinicians will measure the children's cognitive and social skills, take family histories as well as histories of exposure to environmental toxins, and obtain blood and other biological samples. In addition to the M.I.N.D. Institute's community outreach program, UCLA clinicians in the Department of Psychiatry and Biobehavioral Sciences will assist in the evaluations to include a geographically diverse group of urban, rural and minority children.

"This study will be the first major epidemiological case-controlled study to examine autism in relation to a broad array of environmental exposures and endogenous susceptibility factors," Amaral said.

The second project will determine the impact of different toxins on a portion of the brain called the amygdala, which is thought to be involved in controlling social behavior. Led by Amaral and in collaboration with Robert Berman of the UC Davis Department of Neurological Surgery, the project will measure particular social behaviors in monkeys before and after exposure to mercury and thimerosal, which have been widely used in vaccines, and to certain pcbs and pesticides that are commonly found on the ground and in foods such as fish. The exposure levels will be similar to the levels children have experienced.

"This study will provide us with ways to measure and assess social behavior and determine the extent to which environmental toxins can disrupt it," said Amaral.

The project includes developing a battery of behavioral tasks that can provide appropriate assessments of normal mouse and rhesus monkey social behavior. These behaviors will focus on common impairments autistic children suffer, including an apathy for social involvement, an inability to recognize their mothers' facial expressions and a lack of fear of strangers.

The third project will be led by Pessah, whose research specialty is on the impact that environmental chemicals have on the brain's signaling functions. He will use blood samples from the 2,000 children assessed in the center's first project to compare and contrast immune responses to vaccine antigens among the three groups.

"We will carry out the first comprehensive analysis anywhere of the blood levels of toxins, such as mercury, pesticides and pcbs, in children with autism, compared to children without the disorder," Pessah said.

The study also will look at the impact of exposures on the brain's ability to send signals and on cell growth in the nervous system, as well as identify the underlying biochemical process. For instance, mercury is known to have an adverse effect on the immune system. This project will look at mercury in terms of its impact on the nervous system.

Other key researchers who will lead the center's projects will be Robert Berman, Eric Gershwin, Jeff Gregg, Paul Hagerman, Robin Hansen and Judy Van de Water from the School of Medicine; Bruce German and Fumio Matsumura from the College of Agriculture and Environmental Sciences; and Bruce Hammock from the School of Veterinary Medicine.

The new Children's Environmental Health Center builds upon the expertise of established programs at UC Davis, including:

  • The university's toxicological science program, one of the largest and most diverse teaching and research efforts at UC Davis.
  • The Center for Environmental Health Sciences, one of 20 NIEHS sites in the nation.
  • The NIEHS/UC Davis Superfund Basic Research and Training Program, one of 18 such programs nationwide.
  • The Center for Neuroscience, the hub for neuroscientific research on campus.
  • The UC Davis Mouse Biology Program, which focuses research on the genetic basis for diseases that afflict humans and animals.
  • The California Regional Primate Research Center, established by the National Institutes of Health in 1962 to support biomedical research on human health-related problems.
  • The UC Agricultural Health and Safety Center, one of nine such Center for Disease Control centers in the U.S.
  • The UC Davis Genomics Initiative, formed in 1999 to advance gene research.

The announcement above was distributed by UC Davis Health System Public Affairs Office October 25, 2001

For more information, contact:

Isaac Pessah, Director
Professor, School of Veterinary Medicine Dept. of Molecular Biosciences
UC Davis School of Veterinary Medicine, One Shields Avenue, Davis, CA 95616
(530) 752-6696