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Theses and Dissertations

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Browsing Theses and Dissertations by Subject "Alzheimer's disease"

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    Characterization of the Dunkin Hartley guinea pig as a non-transgenic and multimorbid model of brain aging
    (Colorado State University. Libraries, 2024) Glennie, Kristen Skye, author; Hamilton, Karyn L., advisor; Moreno, Julie A., advisor; LaRocca, Thomas J., committee member; Santangelo, Kelly S., committee member
    Alzheimer's Disease and Alzheimer's Disease Related Dementia (AD/ADRD) affect an estimated 55 million people worldwide; a staggering figure that is expected to grow in the coming years. With this projection looming, we have yet to identify any effective cures, treatments, or preventative strategies. Historically, AD/ADRD research is conducted using genetically engineered pre-clinical models, that express a specific brain aging pathology. Recent discoveries, however, have identified a dynamic whole-body "inflammaging" phenotype that exists with, and likely contributes to, AD/ADRD onset and progression. Currently, we do not have an accessible and tractable preclinical model that naturally mimics the age-related, systemic and progressive neurodegenerative phenotype present in humans. Recent findings, however, suggest the Dunkin Hartley guinea pig (HGP) may address this need. HGPs are known to develop systemic inflammation and progressive age-related comorbidities characteristic of human aging. The presence of this whole-body aging phenotype prompted investigation into the brain. Genetic and transcriptomic analyses found aged HGPs exhibit strong sequence homology, and similar protein expression patterns to human brain aging and AD. Further, immunohistochemical assessment found aged HGPs express markers of neuroinflammation and misfolded proteins in the hippocampus. To further interrogate these novel findings, we examined the histopathology of 4 brain regions often implicated in neurodegenerative decline for evidence of progressive neuropathology. Our results identify the presence of an age related neuroinflammatory and phosphorylated tau phenotype. Findings from this study contribute to the overarching hypothesis that AD/ADRD is a whole-body disease, and ultimately support the goal of closing the existing translational gap between preclinical and clinical neurodegenerative research.
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    Novel transcriptomic mechanisms of brain aging
    (Colorado State University. Libraries, 2023) Cavalier, Alyssa Nicole, author; LaRocca, Thomas, advisor; Lark, Daniel, committee member; Hamilton, Karyn, committee member; Weir, Tiffany, committee member
    As the world ages, the incidence of age-related diseases like dementia is expected to increase. Brain aging is characterized by declines in cognitive function that may develop into mild cognitive impairment, which increases the risk for dementia. In fact, age is the primary risk factor for late-onset Alzheimer's disease, which is the most common age-related dementia. The adverse cellular and molecular processes that underlie cognitive decline with aging in the brain are known collectively as the "hallmarks of brain aging." Advances in next-generation sequencing (e.g., transcriptomics/RNA-seq) have made it possible to investigate age- and disease-related changes in the brain at the broad gene expression level, and to identify potential therapeutic targets. With the support of my committee and mentoring team, I completed three studies using transcriptomics that characterize novel mechanisms that underlie brain aging. My findings include: (1) doxorubicin chemotherapy accelerates brain aging at the gene expression level, (2) apigenin nutraceutical supplementation targets age-related inflammation in the brain and rescues cognitive impairment in old mice, and (3) epigenetic dysregulation of transposable elements (remnants of viral infection in the genome) with aging contributes to age-related inflammation in Alzheimer's disease. Together, my work provides insight into transcripts and cellular/molecular pathways that are modifiable and may be therapeutic targets to delay or prevent consequences of brain aging.