Medicine and Health Sciences Commons^™

Apoe And Alzheimer’S Disease: Neuroimaging Of Metabolic And Cerebrovascular Dysfunction, Jason A. Brandon, Brandon C. Farmer, Holden C. Williams, Lance A. Johnson

Physiology Faculty Publications

Apolipoprotein E4 (ApoE4) is the strongest genetic risk factor for late onset Alzheimer’s Disease (AD), and is associated with impairments in cerebral metabolism and cerebrovascular function. A substantial body of literature now points to E4 as a driver of multiple impairments seen in AD, including blunted brain insulin signaling, mismanagement of brain cholesterol and fatty acids, reductions in blood brain barrier (BBB) integrity, and decreased cerebral glucose uptake. Various neuroimaging techniques, in particular positron emission topography (PET) and magnetic resonance imaging (MRI), have been instrumental in characterizing these metabolic and vascular deficits associated with this important AD risk factor. In …

Bilateral Carotid Artery Stenosis Causes Unexpected Early Changes In Brain Extracellular Matrix And Blood-Brain Barrier Integrity In Mice, Jill M. Roberts, Michael E. Maniskas, Gregory J. Bix

Neuroscience Faculty Publications

Bilateral carotid artery stenosis (BCAS) is one experimental model of vascular dementia thought to preferentially impact brain white matter. Indeed, few studies report hippocampal and cortical pathology prior to 30 days post-stenosis; though it is unclear whether those studies examined regions outside the white matter. Since changes in the blood-brain barrier (BBB) permeability precede more overt brain pathology in various diseases, we hypothesized that changes within the BBB and/or BBB-associated extracellular matrix (ECM) could occur earlier after BCAS in the hippocampus, cortex and striatum and be a precursor of longer term pathology. Here, C57Bl/6 mice underwent BCAS or sham surgeries …

Central Nervous System Histoplasmosis: Multicenter Retrospective Study On Clinical Features, Diagnostic Approach And Outcome Of Treatment, Joseph Wheat, Thein Myint, Ying Guo, Phebe Kemmer, Chadi A. Hage, Colin Terry, Marwan M. Azar, James Riddell, Peter Ender, Sharon Chen, Kareem Shehab, Kerry Cleveland, Eden Esguerra, James Johnson, Patty Wright, Vanja Douglas, Pascalis Vergidis, Winnie Ooi, John Baddley, David Bamberger, Raed N. Khairy, Holenarasipur R. Vikram, Elizabeth Jenny-Avital, Geetha Sivasubramanian, Karen Bowlware, Barbara Pahud, Juan Sarria, Townson Tsai, Maha Assi, Satish Mocherla

Internal Medicine Faculty Publications

Central nervous system (CNS) involvement occurs in 5 to 10% of individuals with disseminated histoplasmosis. Most experience has been derived from small single center case series, or case report literature reviews. Therefore, a larger study of central nervous system (CNS) histoplasmosis is needed in order to guide the approach to diagnosis, and treatment.

A convenience sample of 77 patients with histoplasmosis infection of the CNS was evaluated. Data was collected that focused on recognition of infection, diagnostic techniques, and outcomes of treatment.

Twenty nine percent of patients were not immunosuppressed. Histoplasma antigen, or anti-Histoplasma antibodies were detected in the …

Low Arousal Positive Emotional Stimuli Attenuate Aberrant Working Memory Processing In Persons With Mild Cognitive Impairment, Lucas S. Broster, Shonna L. Jenkins, Sarah D. Holmes, Gregory A. Jicha, Yang Jiang

Behavioral Science Faculty Publications

Emotional enhancement effects on memory have been reported to mitigate the pathophysiology of Alzheimer’s disease (AD). However, relative to their manifestation in persons without pathologic aging, these effects may be reduced in magnitude or even deleterious, especially in tasks that more closely model ecologic memory performance. Based upon a synthesis of such reports, we hypothesized that in persons with AD low arousal positive stimuli would evoke relatively intact emotional enhancement effects, but that high arousal negative stimuli would evoke disordered emotional enhancement effects. To assess this, participants with and without mild cognitive impairment (MCI) presumed to be due to AD …

Alzheimer's Disease Genetics And Abca7 Splicing, Jared B. Vasquez, James F. Simpson, Ryan Harpole, Steven Estus

Physiology Faculty Publications

Both common and rare polymorphisms within ABCA7 have been associated with Alzheimer’s disease (AD). In particular, the rare AD associated polymorphism rs200538373 was associated with altered ABCA7 exon 41 splicing and an AD risk odds ratio of ∼1.9. To probe the role of this polymorphism in ABCA7 splicing, we used minigene studies and qPCR of human brain RNA. We report aberrant ABCA7 exon 41 splicing in the brain of a carrier of the rs200538373 minor C allele. Moreover, minigene studies show that rs200538373 acts as a robust functional variant in vitro. Lastly, although the ABCA7 isoform with an extended …

Nfatc2 Modulates Microglial Activation In The Aβpp/Ps1 Mouse Model Of Alzheimer's Disease, Gunjan D. Manocha, Atreyi Ghatak, Kendra L. Puig, Susan D. Kraner, Christopher M. Norris, Colin K. Combs

Pharmacology and Nutritional Sciences Faculty Publications

Alzheimer’s disease (AD) brains are characterized by fibrillar amyloid-β (Aβ) peptide containing plaques and associated reactive microglia. The proinflammatory phenotype of the microglia suggests that they may negatively affect disease course and contribute to behavioral decline. This hypothesis predicts that attenuating microglial activation may provide benefit against disease. Prior work from our laboratory and others has characterized a role for the transcription factor, nuclear factor of activated T cells (NFAT), in regulating microglial phenotype in response to different stimuli, including Aβ peptide. We observed that the NFATc2 isoform was the most highly expressed in murine microglia cultures, and inhibition or …

Calcium's Role As Nuanced Modulator Of Cellular Physiology In The Brain, Hilaree N. Frazier, Shaniya Maimaiti, Katie L. Anderson, Lawrence D. Brewer, John C. Gant, Nada M. Porter, Olivier Thibault

Pharmacology and Nutritional Sciences Faculty Publications

Neuroscientists studying normal brain aging, spinal cord injury, Alzheimer’s disease (AD) and other neurodegenerative diseases have focused considerable effort on carefully characterizing intracellular perturbations in calcium dynamics or levels. At the cellular level, calcium is known for controlling life and death and orchestrating most events in between. For many years, intracellular calcium has been recognized as an essential ion associated with nearly all cellular functions from cell growth to degeneration. Often the emphasis is on the negative impact of calcium dysregulation and the typical worse-case-scenario leading inevitably to cell death. However, even high amplitude calcium transients, when executed acutely can …

Neurovascular Astrocyte Degeneration In The Hyperhomocysteinemia Model Of Vascular Cognitive Impairment And Dementia (Vcid), Tiffany L. Sudduth, Erica M. Weekman, Brittani Rae Price, Jennifer L. Gooch, Abigail E. Woolums, Christopher M. Norris, Donna M. Wilcock

Sanders-Brown Center on Aging Faculty Publications

Vascular cognitive impairment and dementia (VCID) is the second leading cause of dementia behind Alzheimer’s disease (AD) and is a frequent co-morbidity with AD. Despite its prevalence, little is known about the molecular mechanisms underlying the cognitive dysfunction resulting from cerebrovascular disease. Astrocytic end-feet almost completely surround intraparenchymal blood vessels in the brain and express a variety of channels and markers indicative of their specialized functions in the maintenance of ionic and osmotic homeostasis and gliovascular signaling. These functions are mediated by end-foot enrichment of the aquaporin 4 water channel (AQP4), the inward rectifying potassium channel Kir4.1 and the calcium-dependent …

Translational Models For Vascular Cognitive Impairment: A Review Including Larger Species, Atticus H. Hainsworth, Stuart M. Allan, Johannes Boltze, Catriona Cunningham, Chad Farris, Elizabeth Head, Masafumi Ihara, Jeremy D. Isaacs, Raj N. Kalaria, Saskia A. M. J. Lesnik Oberstein, Mark B. Moss, Björn Nitzsche, Gary A. Rosenberg, Julie W. Rutten, Melita Salkovic-Petrisic, Aron M. Troen

Pharmacology and Nutritional Sciences Faculty Publications

Background: Disease models are useful for prospective studies of pathology, identification of molecular and cellular mechanisms, pre-clinical testing of interventions, and validation of clinical biomarkers. Here, we review animal models relevant to vascular cognitive impairment (VCI). A synopsis of each model was initially presented by expert practitioners. Synopses were refined by the authors, and subsequently by the scientific committee of a recent conference (International Conference on Vascular Dementia 2015). Only peer-reviewed sources were cited.

Methods: We included models that mimic VCI-related brain lesions (white matter hypoperfusion injury, focal ischaemia, cerebral amyloid angiopathy) or reproduce VCI risk factors (old age, hypertension, …

Aβ Vaccination In Combination With Behavioral Enrichment In Aged Beagles: Effects On Cognition, Aβ, And Microhemorrhages, Paulina R. Davis, Ginevra Giannini, Karin Rudolph, Nathaniel Calloway, Christopher M. Royer, Tina L. Beckett, M. Paul Murphy, Frederick Bresch, Dieter Pagani, Thomas Platt, Xiaohong Wang, Amy Skinner Donovan, Tiffany L. Sudduth, Wenjie Lou, Erin L. Abner, Richard J. Kryscio, Donna M. Wilcock, Edward G. Barrett, Elizabeth Head

Sanders-Brown Center on Aging Faculty Publications

Beta-amyloid (Aβ) immunotherapy is a promising intervention to slow Alzheimer’s disease (AD). Aging dogs naturally accumulate Aβ and show cognitive decline. An active vaccine against fibrillar Aβ 1–42 (VAC) in aged beagles resulted in maintenance but not improvement of cognition along with reduced brain Aβ. Behavioral enrichment (ENR) led to cognitive benefits but no reduction in Aβ. We hypothesized cognitive outcomes could be improved by combining VAC with ENR in aged dogs. Aged dogs (11–12 years) were placed into 4 groups: (1) control/control (C/C); (2) control/VAC (C/V); (3) ENR/control (E/C); (4) ENR and VAC (E/V) and treated for 20 months. …