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 …

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 …

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 …

Rad Modulation Of The L-Type Calcium Channel Confers Systolic Advantage In The Heart, Brooke Mildred Ahern

Theses and Dissertations--Physiology

Heart failure is a major public health problem and a leading cause of mortality. This clinical condition affects populations of all ages, and is the result of various cardiomyopathies. Almost half of these patients suffer specifically from heart failure with reduced ejection fraction; these hearts have decreased performance due to a failure of the heart to contract with sufficient force to meet demand. While there are therapies available to increase contractility, none of these enhance contraction without also further promoting pathological signaling and remodeling.

Under normal physiological conditions, the body elevates cardiac output through the fight-or-flight response. This response activates …

The Role Of Microtubule-Associated Protein Tau In Neuronal Excitability And Epileptogenesis, Ryan A. Cloyd

Theses and Dissertations--Physiology

Tauopathies, including Alzheimer’s disease (AD), are devastating diseases with an immense burden on society which is predicted to increase in coming decades. In addition to progressive loss of memory and cognitive function, patients with tauopathies have a 6-10 fold increase in lifetime risk for seizures, and many are diagnosed with epilepsy. The presence of epileptiform activity on electroencephalogram (EEG) recordings from patients with AD predicts faster cognitive decline compared to patients without abnormal EEG readings. Electrophysiological measurements in murine models of AD have identified neuronal hyperexcitability. Furthermore, reducing tau phosphorylation or expression confers seizure resistance in animal epilepsy models. Although …

Involvement Of The Renin Angiotensin System In Marfan Syndrome Associated Thoracic Aortic Aneurysms, Jeff Zheying Chen

Theses and Dissertations--Physiology

Thoracic aortic aneurysms (TAAs) are clinically-silent dilations of the aorta which greatly increase the risk of aortic rupture, a condition with 50-90% mortality. Marfan syndrome (MFS) is caused by mutations in fibrillin-1 (FBN1) and is associated with TAAs. Due to an absence of validated and effective pharmacologic therapies to prevent or reverse TAA, most MFS patients require surgical aortic repair. Understanding MFS associated TAA pathogenesis would direct development of new pharmacologic therapies. Previous research has implicated the renin angiotensin system in TAA. In both males and females, angiotensinogen (AGT) is cleaved serially to generate the main effector peptide angiotensin II …

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 …

Protection From Aortic Aneurysm By Bmal1 Deletion From Smooth Muscle Cells, Jenny Lutshumba

Theses and Dissertations--Physiology

Abdominal aortic aneurysm (AAA) is a devastating condition that occurs primarily among older people with high mortality when a rupture occurs. Currently there is no proven pharmacological therapy for AAA due to poor understanding of the underlying pathogenesis. The brain and muscle transcription factor ARNT-like (Bmal1), which is known to regulate circadian rhythm, has been implicated in vascular pathologies including atherosclerosis and vascular remodeling, but its role in AAA has not been explored.

Vascular smooth muscle is a central player in aneurysm formation and development because it is critical in all three aortic aneurysm hallmark processes including (a) degradation of …

Neuroinflammation In Alzheimer's Disease And Vascular Cognitive Impairment, Erica M. Weekman

Theses and Dissertations--Physiology

It was once believed that the brain was immunologically privileged with no resident or infiltrating immune cells; however, now it is understood that the cells of the brain are capable of a wide range of inflammatory processes and phenotypes. Inflammation in the brain has been implicated in several disease processes such as Alzheimer’s disease (AD) and vascular cognitive impairment and dementia (VCID); however, the role of inflammation in these two dementias is poorly understood.

When we stimulated a pro-inflammatory phenotype with an adeno-associated viral vector in a transgenic mouse model of AD that develops Aβ plaques, we saw a pro-inflammatory …

New Insights Into Post-Sepsis Muscle Weakness Elucidated Using A Novel Animal Model, Allison M. Steele

Theses and Dissertations--Physiology

Sepsis is a severe life-threatening critical illness that damages multiple physiological systems. After hospital discharge, more than 70% of severe sepsis survivors report profound weakness which significantly impacts quality of life. Such weakness gives rise to new limitations of daily living, which ultimately leads to loss of independence in many patients. Despite wide recognition of this serious issue by clinicians and researchers alike, the mechanisms contributing to chronic skeletal muscle dysfunction after sepsis are not well understood. Lack of progress in this field is largely due to the absence of an appropriate animal model; current models are either too mild …

Histological And Behavioral Consequences Of Repeated Mild Traumatic Brain Injury In Mice, Amanda Nicholle Bolton Hall

Theses and Dissertations--Physiology

The majority of the estimated three million traumatic brain injuries that occur each year are classified as “mild” and do not require surgical intervention. However, debilitating symptoms such as difficulties focusing on tasks, anxiety, depression, and visual deficits can persist chronically after a mild traumatic brain injury (TBI) even if an individual appears “fine”. These symptoms have been observed to worsen or be prolonged when an individual has suffered multiple mild TBIs. To test the hypothesis that increasing the amount of time between head injuries can reduce the histopathological and behavioral consequences of repeated mild TBI, a mouse model of …

Ppap2b Expression Limits Lesion Formation In Murine Models Of Atherosclerosis, Paul A. Mueller

Theses and Dissertations--Physiology

Coronary artery disease (CAD) is the leading cause of death in both men and women worldwide and is defined as a narrowing of the coronary arteries due to accumulation of atherosclerotic plaques. Genome-wide association studies have identified risk loci within the gene PPAP2B that confers increased risk of developing CAD. Evidence suggests these aforementioned SNPs are regulating PPAP2B expression in a cis-manner through the interruption of transcription factor binding sites. PPAP2B encodes the lipid phosphate phosphatase 3 enzyme that plays a key role in degrading bioactive lysophosphatidic acid (LPA). LPA has a plethora of effects on vascular tissue and is …

Development And Application Of Gadolinium Free Cardiac Magnetic Resonance Fibrosis Imaging For Multiscale Study Of Heart Failure In Patients With End Stage Renal Disease, Tori A. Stromp

Theses and Dissertations--Physiology

Cardiac magnetic resonance (CMR) is a powerful tool to noninvasively image ventricular fibrosis. Late gadolinium enhancement (LGE) CMR identifies focal and, with T1 mapping, diffuse fibrosis. Despite prevalent cardiac fibrosis and heart failure, patients with end stage renal disease (ESRD) are excluded from LGE. Absence of a suitable diagnostic has limited the understanding of heart failure and obstructed development of therapies in the setting of ESRD. A quantitative, gadolinium free fibrosis detection method could overcome this critical barrier, propelling the advancement of diagnostic, monitoring, and therapy options. This project describes the development of a gadolinium free CMR technique and application …

Attenuating Trigeminal Neuropathic Pain By Repurposing Pioglitazone And D-Cycloserine In The Novel Trigeminal Inflammatory Compression Mouse Model, Danielle N. Lyons

Theses and Dissertations--Physiology

Approximately 22% of the United States population suffers from a chronic orofacial pain condition. One such condition is known as trigeminal neuropathic pain frequently reported as continuous aching and burning pain, often accompanied by intermittent electrical shock-like sensations. Dental procedures or trauma are known causes of peripheral trigeminal nerve injury and inflammation. Patients who have this type of facial pain also suffer from emotional distress. For these reasons, trigeminal neuropathic pain needs to be studied in more detail to improve the understanding of the etiology and maintenance of this condition, as well as to develop effective treatment strategies. The first …

Mechanistic Basis For Atrial And Ventricular Arrhythmias Caused By Kcnq1 Mutations, Daniel C. Bartos

Theses and Dissertations--Physiology

Cardiac arrhythmias are caused by a disruption of the normal initiation or propagation of electrical impulses in the heart. Hundreds of mutations in genes encoding ion channels or ion channel regulatory proteins are linked to congenital arrhythmia syndromes that increase the risk for sudden cardiac death. This dissertation focuses on how mutations in a gene (KCNQ1) that encodes a voltage-gated K⁺ ion channel (Kv7.1) can disrupt proper channel function and lead to abnormal repolarization of atrial and ventricular cardiomyocytes.

In the heart, Kv7.1 coassembles with a regulatory protein to conduct the slowly activating delayed rectifier K^{+ …}