2002 Progress Report: Environmental Factors in the Etiology of Autism; Analytic Biomakers (xenobiotic) Core

EPA Grant Number: R829388C001
Subproject: this is subproject number 001 , established and managed by the Center Director under grant R829388
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: CECEHDPR - University of California at Davis Center for the Study of Environmental Factors in the Etiology of Autism
Center Director: Pessah, Isaac N.
Title: Environmental Factors in the Etiology of Autism; Analytic Biomakers (xenobiotic) Core
Investigators: Hammock, Bruce , German, Bruce , Lango, Jozsef , Watkins, Steve
Current Investigators: Hammock, Bruce , Dettmer, Katja , German, Bruce , Green, Peter , Lango, Jozsef
Institution: University of California - Davis
EPA Project Officer: Hahn, Intaek
Project Period: September 30, 2001 through September 29, 2002
Project Period Covered by this Report: September 30, 2001 through September 29, 2002
RFA: Centers for Children's Environmental Health and Disease Prevention Research (2001) RFA Text |  Recipients Lists
Research Category: Health , Health Effects , Children's Health

Objective:

The two major goals of this core are to develop strategies to profile xenobiotics of concern to childhood neurodevelopment in biological fluids and provide support in metabolomics. The long-term approach is to establish a horizontally integrated database from the genome through the autistic phenotype to aid in developing and testing hypotheses regarding the disorder. Thus the core provides established analytical support for xenobiotic and proteomic profiling, and is currently developing tools to study the metabolome.

Our specific aims are: I.) Determine xenobiotics in serum, urine and food; II.) Determine levels of nutritional and structural lipids in serum samples; III.) Provide general analytical support for the project including the development of methods for possible biomarkers that are considered important.

Progress Summary:

Our work has focused in several areas. The first area is development of infrastructure in the analytical core to support the project as a whole. The major accomplishment has been the purchase and installation of a liquid chromatograph interfaced with an electrospray time of flight mass spectrometer. We now are working with engineers from England to get the equipment to operate at specifications. We expect it to be fully on line within days. This mass spectrometer and a new 96 to 1585 well fluorescent plate reader are available to all members of the project in addition to the other analytical instrumentation. We have developed a secure computer network for handling analytical data and are working on the development of an Oracle database that will interface directly with the statistics core of this project.

The philosophy is to have a variety of analytical methods to look at xenobiotics in tissues as well as natural biomarkers. In some cases where there is a clear hypothesis of exposure and relation to autism, we will use high throughput immunoassays. To this end we have obtained antibodies to PCBs and are establishing the assay for high throughput serum analysis. The laboratory is exploring the use of LC-MS technology to dramatically improve the sensitivity of the detection of pharmaceuticals in serum. Typically 5 or 10 ml of serum are used in these analyses. We are now running pharmacokinetics of low abundance drugs using less than 5 ul of serum. This 1000x improvement in sensitivity means that rather than subjecting children to the trauma of removing blood with syringe, we can use finger pricks. Also, we have consulted with several investigators on how to find facilities for mercury analysis.

One of the major goals of this core is to provide support in metabolomics. The philosophy of our long-term approach is shown in the figure below. We want to drive toward a horizontally integrated database from the genome through the autistic phenotype to aid in developing and testing hypotheses regarding the disease. We provide analytical support for proteomics but we are developing tools to study the metabolome. This high throughput metabolite profiling is taking several forms.

First, we are attempting to cast a wide net and use the electrospray time of flight mass spectrometer to look in a semi quantitative way at a large variety of metabolites in urine and serum of autistic children. The last year has been spent optimizing extraction and concentration protocols. Data have been generated on both GLC –MS and LC-MS analysis and we now are looking at how to analyze these data with the analytical core. This broad screen approach has the advantages of not being limited by hypotheses and looking at many analytes at one time. It is limited by the data being only semi-quantitative, platform dependent, and of course the many variable in the samples including sex, nutrition, age and many other factors.

Second, we are defining several metabolite classes and developing highly sensitive, accurate and precise methods for analyzing the compounds in this class. This approach has the obvious advantages of giving a much higher quality of data and in providing amounts of data that are more simple to analyze. However, it is certain to miss important classes of metabolites. We are following several areas.

One area is the analysis of regulatory lipids. One of the biologies demonstrated by these lipids is described in the paper published with support from the project this year in PNAS. We have found a new branch of the arachidonate cascade that influences a number of factors in developmental biology and inflammation. We are using this target to develop first GLC-MS and LC-triple quadrapole mass spectrometry for the analysis of an entire class of regulatory lipids. We are adding regulatory lipids to this screen in a methodical fashion as researchers in the autism program suggest them. The method in now ready to apply to serum and urine samples of autistic and nonautistic children. The data can be interpreted in terms of enzyme systems that alter lipids.

Similar methods are being developed for other metabolite areas based in part on interest of center investigators. For example we are developing a LC-MS method for the detection and quantitation of tryptophan metabolites in serum and urine based on the anecdotal observation that the urine of some autistic children is pink or blue. Methods are also being developed for general oxidative stress and for vitamin D metabolites.

Future Activities:

We will proceed to define differences in the manner in which autistic children metabolize and eliminate xenobiotics of environmental concern from our case control study. Divergence in lipid metabolism will also be a major priority in year 2.


Journal Articles on this Report : 1 Displayed | Download in RIS Format

Other subproject views: All 20 publications 19 publications in selected types All 18 journal articles
Other center views: All 146 publications 134 publications in selected types All 133 journal articles
Type Citation Sub Project Document Sources
Journal Article Davis BB, Thompson DA, Howard LL, Morisseau C, Hammock BD, Weiss RH. Inhibitors of soluble epoxide hydrolase attenuate vascular smooth muscle cell proliferation. Proceedings of the National Academy of Sciences of the United States of America 2002;99(4):2222-2227. R829388 (2006)
R829388 (Final)
R829388C001 (2002)
R829388C001 (2005)
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  • Supplemental Keywords:

    Autism, metabolomics, lipids, proteomics, xenobiotics,, RFA, Health, Scientific Discipline, PHYSICAL ASPECTS, ENVIRONMENTAL MANAGEMENT, Toxicology, Health Risk Assessment, Chemistry, Epidemiology, Risk Assessments, Susceptibility/Sensitive Population/Genetic Susceptibility, Disease & Cumulative Effects, Physical Processes, Children's Health, genetic susceptability, Biology, Risk Assessment, chemical exposure, neurotoxic, xenobiotics, biomarkers, gene-environment interaction, neurodevelopment, pesticides, exposure, halogenated aromatics, children, neurobehavioral, neurodevelopmental, neurotoxicity, etiology, susceptibility, human exposure, neurobehavioral effects, autism, biological markers, mechanisms, exposure assessment, neurological development, biomarker, synergistic interactions, mercurials

    Progress and Final Reports:

    Original Abstract
  • Final

  • Main Center Abstract and Reports:

    R829388    CECEHDPR - University of California at Davis Center for the Study of Environmental Factors in the Etiology of Autism

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R829388C001 Environmental Factors in the Etiology of Autism; Analytic Biomakers (xenobiotic) Core
    R829388C002 Environmental Factors in the Etiology of Autism; Cell Activation/Signaling Core
    R829388C003 Environmental Factors in the Etiology of Autism; Molecular Biomakers Core
    R829388C004 Environmental Factors in the Etiology of Autism; Childhood Autism Risks from Genetics and the Environment (The CHARGE Study)
    R829388C005 Environmental Factors in the Etiology of Autism; Animal Models of Autism
    R829388C006 Environmental Factors in the Etiology of Autism; Molecular and Cellular Mechanisms of Autism