Medicine and Health Sciences Commons^™

Effects Of Traumatic Brain Injury On The Intestinal Tract And Gut Microbiome, Anthony Desana

Theses and Dissertations--Physiology

Traumatic brain injury (TBI) initiates not only complex neurovascular and glial changes within the brain but also pathophysiological responses that extend beyond the central nervous system. The peripheral response to TBI has become an intensive area of research, as these systemic perturbations can induce dysfunction in multiple organ systems. As there are no approved therapeutics for TBI, it is imperative that we investigate the peripheral response to TBI to identify targets for future intervention. Of particular interest is the gastrointestinal (GI) system. Even in the absence of polytrauma, brain-injured individuals are at increased risk of suffering from GI-related morbidity and …

Alzheimer’S Disease Genetics And Short-Chain Fatty Acid Treatment In Studies Of The Murine Gut Microbiome, Diana Zajac

Theses and Dissertations--Physiology

Elucidating the relationship of the gut microbiome in Alzheimer's Disease (AD) risk and pathogenesis is an area of intense interest. Since 60 to 80% of AD risk is related to genetics and APOE alleles represent the most impactful genetic risk factors for AD, their mechanism(s) of action are under intense scrutiny.

First, I conducted a study on APOE targeted replacement mice to investigate the impact of APOE alleles on the murine gut microbiome. The relative abundance of bacteria from the family Ruminococacceae and related genera increased with APOE2 status. The relative abundance of the class Erysipelotrichia increased with APOE4 status, …

Clinical And Biological Factors Determine Spinal Cord Injury Outcomes: Liquor To Lipids, Ethan Glaser

Theses and Dissertations--Physiology

Spinal cord injuries (SCI) are debilitating and life altering events that can lead to permanent motor and sensory loss. SCI outcomes are impacted by both clinical factors such as blood alcohol content (BAC) at the time of injury as well as biological factors like the lipid-rich myelin debris that accumulates in the injury site. Both clinical and biological factors contribute to SCI recovery, impacting neuroinflammation, locomotor recovery, and histopathology. The purpose of the studies described here is to investigate the role of acute alcohol intoxication and intracellular lipid processing pathways on SCI outcomes in a rodent model.

An elevated BAC …

The Effects Of Extended Fructose Access On Relative Value And Demand For Fructose, Saccharin, And Ventral Tegmental Stimulation, Megan Halloran

Theses and Dissertations--Psychology

Globally, food addiction (FA) is a growing area of research and is largely attributed to the availability of foods that are both energy dense and high in fats and sugars. Further, it has been suggested, that sugar and fat, when consumed frequently, have properties similar to drugs of abuse. While the validity of FA is questioned, researchers have drawn parallels between substance use disorder (SUD) and FA. For example, sugar binge models emphasize craving, withdrawal and binging as primary components of FA, which are also hallmarks of SUD. Additionally, both natural rewards, like sugars, and drug rewards act on the …

Calcium Imaging Of Central Amygdala Activity After Fentanyl Escalation, Samantha Malone

Theses and Dissertations--Psychology

Evidence suggests that rats given long access (LgA) sessions to self-administer (SA) opioids escalate their intake, while also showing greater withdrawal severity and drug-induced reinstatement compared to rats maintained on short access (ShA) daily SA sessions. Little is known about the neural changes that occur during opioid escalation that may impact withdrawal and relapse. Past work examining opioid SA using ShA sessions in rodents has identified the central amygdala (CeA) as an area of interest that becomes hyperactive in acute withdrawal and may be involved in the incubation of craving that occurs after protracted withdrawal. However, these studies have not …

An Investigation Of Hhv6'S Impact On The Cognitive Progression And Microglial Changes In An Alzheimer's Disease Cohort, Charles E. Seaks

Theses and Dissertations--Physiology

The role of herpesviruses and, more specifically, HHV6 in the development of Alzheimer’s disease (AD) and associated cognitive decline is still being investigated. High ubiquity and prevalence in the population have led to a high degree of skepticism about HHV6 as a potential contributor to cognitive decline and dementias. However, recent evidence related to another herpesvirus, herpes simplex virus 1, suggests that reactivation, not carriage, of the virus may be the key factor to explain the dissonance between the virus’ ubiquity and contributions to dementias. With that in mind, we set out to assess cases from the Sanders-Brown Center on …

Investigating The Effects Of In-Vivo Therapeutics Hypoxia Treatment Paradigms In Neurite Outgrowth Patterns, Jae Hyun Yoo

Theses and Dissertations--Medical Sciences

Spinal cord injury, specifically in the cervical C3-C4 region of the cervical spine, contributes to impaired breathing and a diminished quality of life. Therefore it is important to find effective and safe therapeutics to restore breathing function. Indeed, there are a myriad of research being performed in addition to valuable collaboration amongst different institutions. As such, inspired by a previous experiment, we decided to test our hypothesis that an enriching environment consisting of different hypoxic environments - sustained and intermittent hypoxia alongside normoxia - would result in neurite outgrowth. Moreover, we hypothesized that sustained hypoxia would result in the greatest …

Uncovering The Role Of Apoe4 On Alzheimer’S Disease-Related Neuroinflammation, Courtney Marie Kloske

Theses and Dissertations--Physiology

Alzheimer’s disease (AD) is the most common neurodegenerative disease and is characterized by two hallmark pathologies: amyloid-beta plaques (Ab plaques) and hyperphosphorylated, aggregated tau tangles. These pathologies are typically accompanied by the presence of neuroinflammation which is primarily mediated by microglia. Interestingly, several genetic risk factors that increase the risk of AD also have direct impacts on neuroinflammation. Of interest, Apolipoprotein E (ApoE) is the largest genetic risk factor for AD. ApoE has three isoforms- E4 confers an increased risk for AD, E3 is considered the “control” phenotype, and E2 is protective against AD. E4 plays a role in virtually …

Cloning And Functional Characterizations Of Circular Rnas From The Human Mapt Locus, Justin R. Welden

Theses and Dissertations--Molecular and Cellular Biochemistry

Under pathophysiological conditions, the microtubule protein tau (MAPT) forms neurofibrillary tangles that are the hallmark of sporadic Alzheimer’s disease as well as familial frontotemporal dementias linked to chromosome 17 (FTDP-17). In this work, I report that MAPT forms circular RNAs through backsplicing of exon 12 to either exon 10 or exon 7 (12→10; 12→7), and that these circular RNAs are translated into proteins.

Using stable cell lines overexpressing the circular tau RNAs 12→7 and 12→10, we have discovered that the tau circular RNA 12→7 is translated in a rolling circle, giving rise to multiple proteins. This circular RNA …

Cognitive Abilities In Hearing Loss: Perceived And Performance Abilities Of Adults Related To Attention, Memory, And Social Cognition, Karah Gottschalk

Theses and Dissertations--Gerontology

Hearing loss is the most common sensory deficit noted in aging adults. It is commonly known to reduce an individual’s ability to detect, identify, and localize sounds and speech and to cause issues in communication. However, there are other less commonly discussed impacts that hearing loss has beyond the auditory system. Literature suggests a correlation between hearing loss and cognition in aging adults. Similar to hearing loss, the domains of cognition experience performance and functional changes across the life span. In an aging adult, changes related to cognition are also suggested to be associated with hearing loss. This study aimed …

Ceramide-Enriched Extracellular Vesicles: A Role In Enhancing Amyloid-Beta Neurotoxicity And Mitochondrial Damage In Alzheimer’S Disease, Ahmed Elsherbini

Theses and Dissertations--Physiology

Alzheimer’s disease (AD) is an age-dependent, progressive, neurodegenerative disorder that is characterized clinically by the impairment of cognitive functions concomitant with behavioral and personality changes. AD is associated with distinct pathological hallmarks, namely, intracellular neurofibrillary tangles comprised of hyperphosphorylated tau protein, extracellular amyloid beta (Aβ) plaques, and marked brain atrophy. Besides their main role as the core component of amyloid plaques, oligomeric Aβ have been shown to be neurotoxic. The exact mechanism of Aβ neurotoxicity is yet to be elucidated.

Recently, a pathogenic function of small extracellular vesicles- also known as exosomes- has been proposed, suggesting that exosomes can transfer …

Combination Of Investigational Cell-Based Therapy And Deep Brain Stimulation To Alter The Progression Of Parkinson’S Disease, Nader El Seblani

Theses and Dissertations--Pharmacy

Parkinson’s disease (PD) is the second most common neurodegenerative disorder and the motor symptoms are caused by progressive loss of midbrain dopamine neurons. There is no current treatment that can slow or reverse PD. Our current “DBS-Plus” clinical trial (NCT02369003) features the implantation in vivo of autologous Schwann cells (SCs) derived from a patient’s sural nerve into the substantia nigra pars compacta (SNpc) in combination with Deep Brain Stimulation (DBS) therapy for treating patients with advanced PD.

The central hypothesis of our research is that transdifferentiated SCs within conditioned nerve tissue will deliver pro-regenerative factors to enhance the survival of …

Apoe As A Metabolic Regulator In Humans, Mice, And Astrocytes, Brandon C. Farmer

Theses and Dissertations--Physiology

Altered metabolic pathways appear to play central roles in the pathophysiology of late-onset Alzheimer’s disease (AD). Carrier status of the E4 allele of the APOE gene is the strongest genetic risk factor for late-onset AD, and increasing evidence suggests that E4 carriers may be at an increased risk for neurodegeneration based on inherent metabolic impairments. A new appreciation is forming for the role of APOE in cerebral metabolism, and how nutritional factors may impact this role. In chapter 1, the literature on nutritional interventions in E4 carriers aimed at mitigating disease risk is reviewed. Studies investigating the mechanism by which …

Targeting Maladaptive Plasticity After Spinal Cord Injury To Prevent The Development Of Autonomic Dysreflexia, Khalid C. Eldahan

Theses and Dissertations--Physiology

Vital autonomic and cardiovascular functions are susceptible to dysfunction after spinal cord injury (SCI), with cardiovascular dysregulation contributing to morbidity and mortality in the SCI population. Autonomic dysreflexia (AD) is a condition that develops after injury to the sixth thoracic spinal segment or higher and is characterized by potentially dangerous and volatile surges in arterial pressure often accompanied with irregular heart rate, headache, sweating, flushing of the skin, and nasal congestion. These symptoms occur in response to abnormal outflow of sympathetic activity from the decentralized spinal cord typically triggered by noxious, yet unperceived nociceptive stimulation beneath the level of lesion. …

Mutations Of Fus Cause Aggregation Of Rna Binding Proteins, Disruptions In Protein Synthesis, And Dysregulation Of Nonsense Mediated Decay, Marisa Elizabeth Kamelgarn

Theses and Dissertations--Toxicology and Cancer Biology

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by motor neuron death and subsequent muscle atrophy. Approximately 15% of ALS cases are inheritable, and mutations in the Fused in Sarcoma (FUS) gene contribute to approximately 5% of these cases, as well as about 2% of sporadic cases. FUS performs a diverse set of cellular functions, including being a major regulator of RNA metabolism. FUS undergoes liquid- liquid phase transition in vitro, allowing for its participation in stress granules and RNA transport granules. Phase transition also contributes to the formation of cytoplasmic inclusions found in the …

Autologous Peripheral Nerve Grafts To The Brain For The Treatment Of Parkinson's Disease, Andrew Welleford

Theses and Dissertations--Neuroscience

Parkinson’s disease (PD) is a disorder of the nervous system that causes problems with movement (motor symptoms) as well as other problems such as mood disorders, cognitive changes, sleep disorders, constipation, pain, and other non-motor symptoms. The severity of PD symptoms worsens over time as the disease progresses, and while there are treatments for the motor and some non-motor symptoms there is no known cure for PD. Thus there is a high demand for therapies to slow the progressive neurodegeneration observed in PD. Two clinical trials at the University of Kentucky College of Medicine (NCT02369003, NCT01833364) are currently underway that …

Neuroprotective Strategies Following Experimental Traumatic Brain Injury: Lipid Peroxidation-Derived Aldehyde Scavenging And Inhibition Of Mitochondrial Permeability Transition, Jacqueline Renee Kulbe

Theses and Dissertations--Neuroscience

Traumatic brain injury (TBI) represents a significant health crisis. To date there are no FDA-approved pharmacotherapies available to prevent the neurologic deficits caused by TBI. Following TBI, dysfunctional mitochondria generate reactive oxygen and nitrogen species, initiating lipid peroxidation (LP) and the formation of LP-derived neurotoxic aldehydes, which bind mitochondrial proteins, exacerbating dysfunction and opening of the mitochondrial permeability pore (mPTP), resulting in extrusion of mitochondrial sequestered calcium into the cytosol, and initiating a downstream cascade of calpain activation, spectrin degradation, neurodegeneration and neurologic impairment.

As central mediators of the TBI secondary injury cascade, mitochondria and LP-derived neurotoxic aldehydes make promising …

Neurobehavioral Measurements Of Natural And Opioid Reward Value, Aaron Paul Smith

Theses and Dissertations--Psychology

In the last decade, (non)prescription opioid abuse, opioid use disorder (OUD) diagnoses, and opioid-related overdoses have risen and represent a significant public health concern. One method of understanding OUD is as a disorder of choice that requires choosing opioid rewards at the expense of other nondrug rewards. The characterization of OUD as a disorder of choice is important as it implicates decision- making processes as therapeutic targets, such as the valuation of opioid rewards. However, reward-value measurement and interpretation are traditionally different in substance abuse research compared to related fields such as economics, animal behavior, and neuroeconomics and may be …

Vascular Cognitive Impairment And Dementia: The Importance Of Mixed Pathologies From Mouse Models To Humans, Alex Marian Helman

Theses and Dissertations--Molecular and Cellular Biochemistry

Age-related neurologic disease is a significant and growing burden on our society. Although the largest share of research effort has typically been devoted to the common neurodegenerative illnesses (such as Alzheimer’s disease, or AD), the reality is that nearly all cases of neurodegenerative disease possess elements of mixed pathology. Vascular contributions to cognitive impairment and dementia (VCID) is a complex form of dementia, combining aspects of vascular disease and other forms of dementia, such as Alzheimer’s disease. This pathology is heterogeneous and can include cerebral amyloid angiopathy (CAA), hemorrhages, white matter infarcts, and changes to the neurovascular unit. Given the …

Insulin-Like Growth Factor-1 Overexpression Mediates Hippocampal Remodeling And Plasticity Following Tbi, Erica Latrice Littlejohn

Theses and Dissertations--Physiology

Every year over 2.5 million traumatic brain injuries (TBI) occur and are the leading cause of death and disability among adolescents. There are no approved treatments for TBI. Survivors suffer from persistent cognitive impairment due to posttraumatic tissue damage and disruption of neural networks which significantly detract from their quality of life. Posttraumatic cognitive impairment depends in part on the brain's limited ability to repair or replace damaged cells. Immature neurons in the hippocampus dentate gyrus, a brain region required for learning and memory, are particularly vulnerable to TBI. Insulin-like growth factor-1 (IGF1) is a potential therapeutic for TBI because …

The Prebiotic Inulin Beneficially Modulates The Gut-Brain Axis By Enhancing Metabolism In An Apoe4 Mouse Model, Jared D. Hoffman

Theses and Dissertations--Pharmacology and Nutritional Sciences

Alzheimer’s disease (AD) is the most common form of dementia and a growing disease burden that has seen pharmacological interventions primarily fail. Instead, it has been suggested that preventative measures such as a healthy diet may be the best way in preventing AD. Prebiotics are one such potential measure and are fermented into metabolites by the gut microbiota and acting as gut-brain axis components, beneficially impact the brain. However, the impact of prebiotics in AD prevention is unknown. Here we show that the prebiotic inulin increased multiple gut-brain axis components such as scyllo-inositol and short chain fatty acids in the …

The Default Mode Network And Executive Function: Influence Of Age, White Matter Connectivity, And Alzheimer’S Pathology, Christopher A. Brown

Theses and Dissertations--Neuroscience

The default mode network (DMN) consists of a set of interconnected brain regions supporting autobiographical memory, our concept of the self, and the internal monologue. These processes must be maintained at all times and consume the highest amount of the brain’s energy during its baseline state. However, when faced with an active, externally-directed cognitive task, the DMN shows a small, but significant, decrease in activity. The reduction in DMN activity during the performance of an active, externally-directed task compared to a baseline state is termed task-induced deactivation (TID), which is thought to ‘free-up’ resources required to respond to external demands. …

Oxidative Stress And Proteomic Studies Of Mammalian Models Of Age-Related Metabolic Dysfunction In Neurodegenerative Disorders, Aaron M. Swomley

Theses and Dissertations--Chemistry

Expression proteomics is the field of science wherein proteins that make up the cellular proteome are identified both by name and by fold-change. Depending on the application of proteomics, this change in level could be due to internal cellular stressors or introduction of xenobiotics. Global oxidative stress measures use immunohistochemistry to determine the relative level of oxidative stress of macromolecules within the cell. In this dissertation, both global oxidative stress measures and expression proteomics were used in a variety of mammalian models in order to determine the effects of protein upregulation, intranasal insulin administration, and resveratrol supplementation on the cellular …

Chronic Pancreatitis, Pain, And Anxiety In An Alcohol And High Fat Mouse Model, Tiffanie Clinkinbeard

Theses and Dissertations--Gerontology

Homeodynamic space (HDS) shrinks as vulnerability increases with aging and repeated damage to the cells. HDS is lost in alcoholic pancreatitis patients due to overconsumption of alcohol, smoking, and high fat diets. Etiologically relevant animal models for study of chronic pancreatitis (CP) are needed. In order to begin filling this gap a central purpose of this dissertation research was to examine relationships between the alcohol and high fat diet (AHF) and pancreatitis with attention to hypersensitivity and anxiety-like behaviors. The AHF diet induced pancreatitis described here etiologically mimics human risk factors of AHF consumption for advancement to alcoholic CP.

In …

Probing The Functional Relevance Of Reactive Hippocampal Neurogenesis In A Model Of An Alcohol Use Disorder, Chelsea Rhea Geil Nickell

Theses and Dissertations--Pharmacy

Alcoholism, or alcohol use disorders (AUDs), represent a major public health concern both locally and globally. Critically, excessive alcohol consumption results in neurodegeneration in brain regions such as the hippocampus which is known for its role in learning and memory. Recovery of hippocampal volume loss has been observed after prolonged abstinence, but the mechanisms underlying this process are not well understood. Adult neurogenesis is thought to contribute to this recovery since after alcohol exposure a reactive increase in adult neurogenesis is observed. This reactive neurogenesis (the process by which brain insult results in a compensatory increase in neurogenesis) may represent …

The Role Of Sox4 In Regulating Choroid Fissure Closure And Retinal Neurogenesis, Wen Wen

Theses and Dissertations--Biology

The development of the vertebrate eye is tightly controlled by precise genetic regulations. From a single ocular primordium to bilateral eyes with complex structures and cell types, it requires intensive proliferation and migration for cells in both the ectoderm and mesoderm to accomplish ocular morphogenesis, and during this process cell differentiation and interaction takes place to establish the complex composition of ocular cell types and cellular connections. Genetic defects can lead to severe abnormalities in eye morphogenesis and cell differentiation during ocular development. A tremendous amount of work has been done to identify both intrinsic and extrinsic factors that regulate …

Targeting Methylglyoxal And Ppar Gamma To Alleviate Neuropathic Pain Associated With Type 2 Diabetes, Ryan B. Griggs

Theses and Dissertations--Physiology

Neuropathic pain affects up to 50% of the 29 million diabetic patients in the United States. Neuropathic pain in diabetes manifests as a disease of the peripheral and central nervous systems. The prevalence of type 2 diabetes is far greater than type 1 (90%), yet the overwhelming focus on type 1 models this has left the mechanisms of pain in type 2 diabetes largely unknown. Therefore I aimed to improve the current mechanistic understanding of pain associated with type 2 diabetes using two preclinical rodent models: Zucker Diabetic Fatty rats and db/db mice. In addition, I highlight the translational importance …

The Effects Of Spinal Manipulative Therapy On Isokinetic Strength And Postactivation Potentiation, Grant D. Sanders

Theses and Dissertations--Kinesiology and Health Promotion

Spinal manipulative therapy (SMT) is a therapeutic procedure employed by various healthcare practitioners for alleviating acute and chronic musculoskeletal complaints. This form of treatment is also delivered to enhance the performance and augment the rehabilitation of athletes. However, despite research findings alleging the strength-modulating effects of SMT alongside numerous professional athletes’ positive anecdotal claims concerning its results, the physiological processes to explain its effects remain largely unexplained. Therefore, the purpose of this work was to investigate the effects of SMT in a college-aged sample population with two experiments.

The first study examined the effect of SMT targeting the lumbosacral region …

Flavonoids With Novel Nicotinic Activity As Potential Pharmacotherapies To Treat Ethanol-Induced Neurotoxicity, Joseph A. Lutz

Theses and Dissertations--Pharmacy

Ethanol causes neurotoxicity via several mechanisms at different points in the cycle of dependence, including neuroinflammation and oxidative stress during ethanol exposure as well as excitotoxicity during ethanol withdrawal. The primary therapeutic implication is that ethanol-induced neurotoxicity requires multifunctional pharmacotherapies which reduce all mechanisms. Using an innovative pharmacological high throughput screening method on a large plant extract library we discovered flavonoids with alpha7 nicotinic acetylcholine receptor (nAChR) activity. In addition to their well-known anti-inflammatory and antioxidant properties, this novel activity means they can potentially reduce excitotoxicity and therefore makes them ideal for inhibition of ethanol-induced neurotoxicity. Rhamnetin, the candidate compound, …

Immunotherapy In Combination With Behavioral Enrichment In A Canine Model Of Aging, Paulina R. Davis

Theses and Dissertations--Pharmacology and Nutritional Sciences

Alzheimer’s disease (AD) is characterized by cognitive decline and hallmark neuropathology, including β-amyloid (Aβ). Therapeutic strategies for AD are focusing on reducing Aβ. Canines develop Aβ neuropathology and cognitive decline with age similar to AD patients. In previous studies, immunization with Aβ1-42 (VAC) in aged canines decreased brain Aβ but did not improve cognition. Behavioral enrichment (ENR) improved cognition without reducing brain Aβ. We hypothesized that VAC combined with ENR would provide cognitive benefits and reduce Aβ neuropathology, as compared individual VAC and ENR treatments. Aged beagles were placed into groups: control, VAC with fibrillar Aβ1-42, ENR, and combination treatment …