Effects of A-beta Immunotherapy and Omega-3 Fatty Acid Administration in Alzheimer’s Transgenic Mice by Maren T. Jensen A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Biology College of Arts and Sciences University of South Florida Major Professor: Gary Arendash, Ph.D. Huntington Potter, Ph.D. Sidney Pierce, Ph.D. Brian Livingston, Ph.D. Date of Approval: March 6, 2006 Keywords: Active Vaccination, Fish Oil, DHA, Cognitive Performance, Plaque Deposition © Copyright 2006, Maren T. Jensen Acknowledgements I thank Dr. David Morgan for providing the animals utilized in the Aβ immunotherapy study and Dr. Marcia Gordon for her involvement in the animal vaccinations and Aβ immunostaining. I would also like to thank Purina Mills Test Diet for providing the low omega-3, omega-3-deficient, high n-3 and high n-6 fatty acid diets and Barrow-Agee Laboratories for analyzing all four of the fatty acid diets. In addition, I would like to thank Dr. Norman Salem and Dr. Nahed Hussein for their determination of fatty acid levels from the frontal cortex. Table of Contents List of Tables ..................................................................................................................... iii List of Figures..................................................................................................................... v Introduction......................................................................................................................... 1 Alzheimer’s Disease Background................................................................................. 1 AD Behavioral Deficits................................................................................................. 2 AD Pathology................................................................................................................ 5 Cerebral Atrophy, Neuronal Loss........................................................................... 5 Neuritic Plaques...................................................................................................... 7 Neurofibrillary Tangles......................................................................................... 12 Genetics of AD ........................................................................................................... 16 Diagnosis of AD ......................................................................................................... 18 Risk Factors for AD.................................................................................................... 25 Treatment of AD......................................................................................................... 29 Animal Models............................................................................................................ 36 PDAPP Transgenic Mice. ..................................................................................... 38 APPsw Transgenic Mice....................................................................................... 44 APP/PS1 Transgenic Mice.................................................................................... 52 AD Vaccination .......................................................................................................... 55 In Vitro Studies..................................................................................................... 55 Active Aβ Immunotherapy. .................................................................................. 56 Passive Aβ Immunotherapy.................................................................................. 64 Aβ Immunotherapy in Humans. ........................................................................... 69 Omega-3 Fatty Acids ................................................................................................. 70 General Background. ............................................................................................ 70 Dietary Manipulation of n-3 and n-6 Fatty Acids................................................. 75 Human Studies Involving Fatty Acids.................................................................. 83 Neurochemical Effects of n-3 Fatty Acids............................................................ 89 Effects of n-3 Fatty Acids on 2nd Messengers. ..................................................... 97 Behavioral Effects of n-3 Fatty Acids in Animals.............................................. 104 Statement of Purpose ................................................................................................ 115 Materials and Methods.................................................................................................... 117 Life-long Vaccination Study..................................................................................... 117 Omega-3 Fatty Acid Study- Survival Analysis ........................................................ 121 i Omega-3 Fatty Acid Study- Behavioral, Pathologic and Neurochemical Assessments........................................................................ 126 Behavioral Testing Procedures ................................................................................. 136 Statistical Analysis.................................................................................................... 143 Results............................................................................................................................. 146 Life-long Vaccination Study..................................................................................... 146 Sensorimotor- and Anxiety-based Tasks. ........................................................... 147 Cognitive-based Tasks........................................................................................ 151 Aβ Histopathology.............................................................................................. 167 FA and Correlation Analyses.............................................................................. 169 DFA..................................................................................................................... 172 Omega-3 Fatty Acid Study- Survival Analyses........................................................ 176 Omega-3 Fatty Acid Study: Behavioral, Pathologic and Neurochemical Assessments........................................................................ 181 Sensorimotor- and Anxiety-Based Tasks............................................................ 184 Cognitive-based Tasks........................................................................................ 188 Cytokine Levels .................................................................................................. 211 Hippocampal Aβ levels....................................................................................... 211 Fatty Acid Brain Tissue Levels........................................................................... 216 Correlations and Multimetric Analyses .............................................................. 222 Discussion....................................................................................................................... 238 Aβ Vaccination Discussion....................................................................................... 238 Omega-3 Discussion ................................................................................................ 248 Survival Analysis................................................................................................ 249 Behavioral, Pathologic and Neurochemical Assessments. ................................. 251 Overall Conclusions.................................................................................................. 267 References....................................................................................................................... 269 ii List of Tables Table 1. Summary of behavioral studies involving n-3 deficiency or supplementation to rodents………………………………………….……..107 Table 2. Percent fatty acid composition of total fat for standard chow, low omega-3 diet and omega-6 deficient diets……………...………...125 Table 3. Percent fatty acid composition of total fat for standard chow, high omega-3 and high omega-6 diets…………………………....…...130 Table 4. A summary of transgenic and immunotherapy at both 4½-6 and 15-16½ month test points………………………...………………..146 Table 5. Total Aβ and compact Aβ for Tg+/Con and Tg+/Aβ at 17 months of age within frontal cortex and hippocampus……………………168 Table 6. Factor Loadings of behavioral measures, with and Without pathologic measures………………………………...……………….171 Table 7. Summary of discriminant function analyses…………………………….……174 Table 8. A summary of transgenic and dietary behavioral effects (high n-3 vs. high n-6) in NT and Tg+ mice………………………………….182 Table 9. A summary of transgenic and dietary behavioral effects (high n-3 vs. standard diet) in NT and APP/PS1 mice……………………….183 Table10. Correlations for all NT mice combined between cortical fatty acid levels and behavioral measures or for only high n-3 and high n-6 NT mice between fatty acid levels, plasma cytokines and behavioral performance…………………………………….…224 Table 11. Correlations for combined standard and high n-3 APP/PS1 mice between behavioral measures, cortical fatty acid levels and hippocampal Aβ levels or for combined high n-3 and high n-6 APP/PS1 mice between hippocampal Aβ levels, plasma cytokines and brain fatty acid levels………………………...……….227 iii