Institute for Agriculture and Trade Policy

Size: px

Start display at page:

Download "Institute for Agriculture and Trade Policy"

Homer Alexander
6 years ago
Views:

1 January 21, 2006 Institute for Agriculture and Trade Policy Integrated Approaches to Understand Autism Isaac N. Pessah, Ph.D. Center for Children s s Environmental Health The M.I.N.D. Institute University of California, Davis

2 Genetic and Epigenetic Mechanisms Conferring Susceptibility To Environmental Agents

3 Autism is a Complex Disorder

4 What we don t know about environmental triggers ----quite a bit! >53,000 commercially important chemicals NTP survey of 49,000 industrial chemicals ~80% lack adequate toxicity data (especially( DNT) 3,400 pesticides are more heavily regulated ~64% lack adequate data for risk assessment 3,400 cosmetic ingredients ~74% lack adequate data for risk assessment 8,600 food additives ~80 % lack adequate data for risk assessment National Toxicology Program Report (1992)

5 Overall Working Hypothesis Environmental Factors Genetic susceptibly Dysfunctional phenotype Repair Normal phenotype

UCDavis Center for Children s Environmental Health Gene -

Pessah Director Irva Hertz- Picciotto Deputy Director Principal

Frank Sharp Paul Hagerman Bruce Hammock Robin Hansen Judy Van de

6 UCDavis Center for Children s Environmental Health Gene - Environment Interactions in the Etiology of Autism Isaac N. Pessah Director Irva Hertz- Picciotto Deputy Director Principal Investigators: David Amaral Robert Berman Lisa Croen Jeff Gregg Frank Sharp Paul Hagerman Bruce Hammock Robin Hansen Judy Van de water Sponsors: UCDavis M.I.N.D. NIEHS U.S. EPA

7 UC Davis Center for Children s Environmental Health Gene-Environment Interactions in the Etiology of Autism * *COTC- Community Outreach and Translation Core

8 UC Davis Center for Children s Environmental Health Gene-Environment Interactions in the Etiology of Autism M.I.N.D. Institute CA Dept. Developmental Svc. UC Davis Mouse Behavior Lab UC Davis CEHS Advisory Committees UC Davis SBRP

9 The CHARGE Study CHildhood Autism Risk from Genes and the Environment Irva Hertz-Picciotto, M.P.H., Ph.D. Robin Hansen, M.D. Lisa Croen, Ph.D. Be in charge

10 The CHARGE Study CHildhood Autism Risk from Genes and the Environment Table 1. Enrollment/Clinical Progress Overview Subject Group Enrolled Parent Module Completed Be in charge Child Module Completed Clinic Visits Autism MR/DD General Population Unaffected Twin N/A N/A Total Exposure Questionnaire Completed Table 2. Specimen Collection Blood Urine Hair Baby Locks Index Child Mother N/A Father N/A Sibling N/A Total

11 Transcriptional Analysis of Autism and Developmental Delays Jeff Gregg, MD, PhD Frank Sharp, MD

12 Transcriptional Signature of Autism

13 Transcriptional Signature of Autism Signature reveals 12 dysregulated genes in autism All 12 genes are natural killer (NK) cell biomarkers

14 Are autistic children immunologically unique? Objective 1: 1 Assessment of humoral immunity: Profile serologic samples to assess: Total immunoglobulin levels (IgG, IgA, IgM and IgE). Determine the titers of specific vaccine and viral antigens. Determine the presence of autoantibodies to brain antigens. Dr. Judy Van DeWater, by permission

15 Immunoglobulin Levels in Children With Autism Immunoglobulin Autism General Population Siblings Disease controls Total IgA 5.25 ± * ± * ± * ± 1.53 (mg/ml) Total IgG 7.82 ± *# ± ± * ± 1.63 (mg/ml) Total IgM 0.94 ± * ± ± ± 0.19 (mg/ml) Total IgE ± ± ± ± 12.6 (IU/ml) p<0.004* compared with ASD; # compared with Siblings Dr. Judy Van DeWater, by permission

16 IgG Response to Bacterial Vaccine Antigens in Children With Autism Antigen Autism General Population Siblings Disease controls Diptheria IgG (IU/ml) 0.28 ± * ± ± ± 0.18 Tetanus IgG 0.46 ± * ± ± ± 0.8 (IU/ml) Bordetella IgG 5.58 ± * ± * ± * ± 4.32 (IU/ml) p<0.004* compared with ASD Dr. Judy Van DeWater, by permission

17 IgG Response to Viral Vaccine Antigens in Children With Autism Antigen Autism General Population Siblings Disease controls Measles IgG ± ± ± ± 9.37 (IU/ml) Mumps IgG ± ± ± ± (IU/ml) Rubella IgG 1.82 ± ± ± ± 0.11 (Ab index) No significant differences when age is factored in. Dr. Judy Van DeWater, by permission

18 Preliminary Conclusions Plasma Immunoglobulin Levels Autistic children have reduced levels of IgG, IgA and IgM. Siblings have an identical reduction in IgG and IgA. Contrary to previous studies, patients with autism do not have elevated IgE levels.

19 Preliminary Conclusions Response to Vaccine Antigens Patients with autism have a reduced response to bacterial vaccine antigens. This is especially significant for Bordetella pertussis. This reduced response was not noted in the sibling population.

20 Is there an autoimmune component in some cases of autism? Autoantibodies to Neuronal Antigens

Immune dysfunction in Autism Autism IgG-2

activity increased number of midline crossings,

in maternal serum of women who gave birth to

001 Midline Crossings 12 8 4 PKU IgG-1 IgG-2

21 Immune dysfunction in Autism Autism IgG-2 infants show an unusual pattern of excessive activity increased number of midline crossings, paces, and approaches Autoantibodies are found in maternal serum of women who gave birth to autistic children P<0.001 Midline Crossings PKU IgG-1 IgG-2 Control Patient Control 0 Control Group 2 Group 1 Dr. Judy Van DeWater, by permission

Mercury is an immunotoxicant MeHg is a well-known immunotoxicant. Some exposure effects noted in mice are: Reduced primary and secondary immune responses.

22 Mercury is an immunotoxicant MeHg is a well-known immunotoxicant. Some exposure effects noted in mice are: Reduced primary and secondary immune responses. Thymic atrophy. Impaired ability to handle infections. Generation of autoimmunity in genetically susceptible animals and possibly humans (both MeHg and inorganic Hg).

23 UCDavis Center for Children s Environmental Health Analytical Capabilities Blood analysis of 22 metals in blood PCBs and PBDEs fipronil (frontline) pyrethroids lipid profile oxylipid metabolites eicosanoids Urine opioid peptides tryptophan metabolites Hair mercury

24 UCDavis Center for Children s Environmental Health Analytical Core: Metals Analysis Mg vs. Hg (µg/l) /100 children blood levels >5.8µg/L Mg Dr. Peter Green, by permission Hg

Cellular Mechanisms of toxicity THI interferes with expression of invariant chain (Ii) and increases binding of antigen to MHCII sites on DC cell surface A 20% loss of

25 Cellular Mechanisms of toxicity THI interferes with expression of invariant chain (Ii) and increases binding of antigen to MHCII sites on DC cell surface A 20% loss of invariant chain protein expression in THI treated DC (n=3) A A 36% gain in peptide binding by THI treated DC (n=3) B medium medium Count THI Count THI Invariant Chain OVA peptide

26 EXPOSURE to PCBs & PBDE Polychlorinated biphenyl (non coplanar PCB) Cl x Cl y Br x O Br y Polybrominated diphenylether (non coplanar PBDE)

27 Perinatal exposure to low-level PCB 95 alters wiring of the primary auditory cortex Normal receptive field within primary auditory cortex (PN35-50) Perinatal PCB 95 Kenet et al, submitted

28 Exposure to PCB 95 Enhances Seizure Susceptibility Corn oil PCB 95 1 mg/kg PCB 95 6 mg/kg * * * Stages * * PTZ injections (days) Kim et al, in preparation

29 Center for Children s Environmental Health Integrated Approach to Understanding Autism PCBs insecticides Dysfunction/ Down regulation GABA A Receptors Repair Hg 2+ CxxC Dysfunctional phenotype Normal phenotype Hypothesis generating concept: environmental noise x genetic susceptibilities x timing = prevalence and severity of developmental disorders

30 Center for Children s Environmental Health Integrated Approach to Understanding Autism

Immunologic Factors in the Etiology of Autism

Immunologic Factors in the Etiology of Autism Judy Van de Water, Ph.D. Professor, Department of Internal Medicine University of California, Davis UC Davis M.I.N.D. Ititute javandewater@ucdavis.edu Neuro-immune