Patients with Alzheimer?s disease (AD) suffer a progressive loss of memory and cognitive ability, and eventual loss of basic bodily functions and death. The incidence and toll of AD on the healthcare system continues to rise with significant societal impact. There are no treatments for AD to prevent its inexorable course, and the principal obstacle to developing new therapies for AD has been the inadequacy of available preclinical modeling, which almost exclusively involves rodents. Nonhuman primates (NHPs) share greater homology to humans than rodents in all respects, including genomics, physiology, cognitive processing, neuronal network complexity and dynamics of drug/target interactions. Given these translational advantages, the long-term goal of this project is to develop a new NHP model of AD that can be standardized and deployed in rigorous, reproducible studies to overcome critical current deficiencies in translating preclinical studies into novel clinical diagnostic strategies and therapies. The objective of this application is to expand and advance our Phase I work on a NHP model of AD in which intrathecal administration of amyloid ?-oligomers (A?Os) induces increased expression of phosphorylated tau in the medial temporal cortical memory circuit. This finding is consistent with our overall hypothesis that A?Os will trigger a cascade of accelerated pathology that mimics the changes occurring in the brains of AD patients. This hypothesis is based on a growing consensus in the AD research field that A?Os are the toxic species that provoke deposition of the characteristic tangles and plaques in the brain together with loss of neurons and synapses and associated cognitive decline. The hypothesis will be tested further in statistically meaningful designs by pursing three specific aims: 1) Determine the extent and persistence of induced cognitive deficits; 2) Confirm the predictive validity of the model using a pharmacological intervention, and 3) Assess the utility of EEG recordings from telemetry implants to track ongoing AD-like pathology. These studies will utilize in-life biomarkers (MRI-determined hippocampal volume, CSF analytes) together with post-mortem measurements (immunohistochemistry, biochemistry, electron microscopy) to establish the impact of A?Os administration in the brain of male and female St. Kitts green monkeys, a species that has been well characterized for its propensity to develop naturally occurring features of AD pathology. The approach is innovative because it represents a substantial shift from current AD research paradigms and tests a novel theoretical concept. The research is significant because it is expected to 1) overcome critical deficiencies in current animal AD models by validating an accelerated, inducible NHP model of sporadic AD in both males and females, 2) permit effective translation of basic discoveries into novel clinical diagnostic strategies and therapies, and 3) help understand possible sex differences in disease susceptibility and progression. Success with this program would provide a valuable resource to research groups in need of a relevant, reliable model of AD for basic research, and diagnostic and therapeutic development.
This project is relevant to public health because establishing a new model of Alzheimer's disease would increase understanding of its pathology and lead to earlier diagnoses and new and more effective treatments. The research has direct relevance to the goals of several NIH institutes in addition to NIA and ORIP, such as NIBIB, NIEHS, NIMH, NINDS and NIAID and is relevant to the part of NIH's mission that pertains to fostering fundamental discoveries and research strategies that will help to reduce the burdens of human disability.
