title: Molecular and cellular pathophysiology of preclinical Alzheimer's disease.
abstract: Although the two pathological hallmarks of Alzheimer's disease (AD), senile plaques composed of amyloid-β (Aβ) peptides and neurofibrillary tangles (NFTs) consisting of hyperphosphorylated tau, have been studied extensively in postmortem AD and relevant animal and cellular models, the pathogenesis of AD remains unknown, particularly in the early stages of the disease where therapies presumably would be most effective. We and others have demonstrated that Aβ plaques and NFTs are present in varying degrees before the onset and throughout the progression of dementia. In this regard, aged people with no cognitive impairment (NCI), mild cognitive impairment (MCI, a presumed prodromal AD transitional state, and AD all present at autopsy with varying levels of pathological hallmarks. Cognitive decline, a requisite for the clinical diagnosis of dementia associated with AD, generally correlates better with NFTs than Aβ plaques. However, correlations are even higher between cognitive decline and synaptic loss. In this review, we illustrate relevant clinical pathological research in preclinical AD and throughout the progression of dementia in several areas including Aβ and tau pathobiology, single population expression profiling of vulnerable hippocampal and basal forebrain neurons, neuroplasticity, neuroimaging, cerebrospinal fluid (CSF) biomarker studies and their correlation with antemortem cognitive endpoints. In each of these areas, we provide evidence for the importance of studying the pathological hallmarks of AD not in isolation, but rather in conjunction with other molecular, cellular, and imaging markers to provide a more systematic and comprehensive assessment of the multiple changes that occur during the transition from NCI to MCI to frank AD.
authors.affiliation: Departments of Neurobiology and Neurology, Barrow Neurological Institute, Phoenix, AZ, United States. Electronic address: Elliott.Mufson@dignityhealth.org.
authors.forename: Elliott J
authors.initials: EJ
authors.lastname: Mufson
authors.affiliation: Departments of Neurology and Psychiatry, University of Pittsburgh, and Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, United States.
authors.forename: Milos D
authors.initials: MD
authors.lastname: Ikonomovic
authors.affiliation: Department of Translational Science and Molecular Medicine, Department of Family Medicine, Hauenstien Neuroscience Institute, Mercy Health Saint Mary's Hospital, Grand Rapids, MI, United States.
authors.forename: Scott E
authors.initials: SE
authors.lastname: Counts
authors.affiliation: Departments of Neurobiology and Neurology, Barrow Neurological Institute, Phoenix, AZ, United States.
authors.forename: Sylvia E
authors.initials: SE
authors.lastname: Perez
authors.affiliation: Banner Alzheimer's Institute, Phoenix, AZ, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Malek-Ahmadi
authors.affiliation: Sanders Brown Center on Aging, University of Kentucky, Lexington, KY, United States.
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Scheff
authors.affiliation: Center for Dementia Research, Nathan Kline Institute, Department of Psychiatry, Department of Neuroscience & Physiology, New York University Langone Medical Center, Orangeburg, NY, United States.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Ginsberg
mesh_terms: D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D000818:Animals; D006801:Humans; D009474:Neurons / Q000473:pathology / Q000502:physiology; D062706:Prodromal Symptoms