Medicine and Health Sciences Commons^™

Effects Of Season And Nutrition On Insulinemic Responses In Insulin Dysregulated Horses, Erica Lyn Macon

Theses and Dissertations--Veterinary Science

Insulin dysregulation (ID) is the main risk factor for the development of hyperinsulinemia-associated laminitis (HAL). ID in the equid has been extensively researched; however, recommendations for diagnosing and managing ID horses have originated from work completed in other models, such as the ID pony and healthy horse. Therefore, our overall objective was to improve current diagnostic tools and nutritional management strategies by investigating the effect of season, the fed and fasted state on the oral sugar test (OST) and dietary nutrient content on insulinemic responses in the ID horse. To address this, four main objectives with three specific aims were …

Using Neonatal Skin To Study The Developmental Programming Of Aging, Leryn J. Reynolds, Brett J. Dickens, Benjamin B. Green, Carmen J. Marsit, Kevin J. Pearson

Pharmacology and Nutritional Sciences Faculty Publications

Numerous studies have examined how both negative and positive maternal exposures (environmental contaminants, nutrition, exercise, etc.) impact offspring risk for age-associated diseases such as obesity, type 2 diabetes, hypertension, and others. The purpose of this study was to introduce the foreskin as a novel model to examine developmental programming in human neonates, particularly in regard to adipogenesis and insulin receptor signaling, major contributors to age-associated diseases such as obesity and diabetes. Neonatal foreskin was collected following circumcision and primary dermal fibroblasts were isolated to perform adipocyte differentiation and insulin stimulation experiments. Human neonatal foreskin primary fibroblasts take up lipid when …

Apolipoprotein E4 And Insulin Resistance Interact To Impair Cognition And Alter The Epigenome And Metabolome, Lance A. Johnson, Eileen Ruth S. Torres, Soren Impey, Jan F. Stevens, Jacob Raber

Physiology Faculty Publications

Apolipoprotein E4 (E4) and type 2 diabetes are major risk factors for cognitive decline and late onset Alzheimer’s disease (AD). E4-associated phenotypes and insulin resistance (IR) share several features and appear to interact in driving cognitive dysfunction. However, shared mechanisms that could explain their overlapping pathophysiology have yet to be found. We hypothesized that, compared to E3 mice, E4 mice would be more susceptible to the harmful cognitive effects of high fat diet (HFD)-induced IR due to apoE isoform-specific differences in brain metabolism. While both E3 and E4 mice fed HFD displayed impairments in peripheral metabolism and cognition, deficits in …

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 …

The Impact Of Sglt2 Inhibitors, Compared With Insulin, On Diabetic Bone Disease In A Mouse Model Of Type 1 Diabetes, Kathryn M. Thrailkill, Jeffry S. Nyman, R. Clay Bunn, Sasidhar Uppuganti, Katherine L. Thompson, Charles K. Lumpkin, Evangelia Kalaitzoglou, John L. Fowlkes

Barnstable Brown Diabetes Center Faculty Publications

Skeletal co-morbidities in type 1 diabetes include an increased risk for fracture and delayed fracture healing, which are intertwined with disease duration and the presence of other diabetic complications. As such, chronic hyperglycemia is undoubtedly a major contributor to these outcomes, despite standard insulin-replacement therapy. Therefore, using the streptozotocin (STZ)-induced model of hypoinsulinemic hyperglycemia in DBA/2J male mice, we compared the effects of two glucose lowering therapies on the fracture resistance of bone and markers of bone turnover. Twelve week-old diabetic (DM) mice were treated for 9 weeks with: 1) oral canagliflozin (CANA, dose range ~10-16 mg/kg/day), an inhibitor of …

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 …

Effects Of Exercise On Ampk Signaling And Downstream Components To Pi3k In Rat With Type 2 Diabetes, Shicheng Cao, Bowen Li, Xuejie Yi, Bo Chang, Beibei Zhu, Zhenzhen Lian, Zhaoran Zhang, Gang Zhao, Huili Liu, He Zhang

Barnstable Brown Diabetes Center Faculty Publications

Exercise can increase skeletal muscle sensitivity to insulin, improve insulin resistance and regulate glucose homeostasis in rat models of type 2 diabetes. However, the potential mechanism remains poorly understood. In this study, we established a male Sprague-Dawley rat model of type 2 diabetes, with insulin resistance and β cell dysfunction, which was induced by a high-fat diet and low-dose streptozotocin to replicate the pathogenesis and metabolic characteristics of type 2 diabetes in humans. We also investigated the possible mechanism by which chronic and acute exercise improves metabolism, and the phosphorylation and expression of components of AMP-activated protein kinase (AMPK) and …

Mice Deficient In Gem Gtpase Show Abnormal Glucose Homeostasis Due To Defects In Beta-Cell Calcium Handling, Jenny E. Gunton, Mary Sisavanh, Rebecca A. Stokes, Jon Satin, Leslie S. Satin, Min Zhang, Sue M. Liu, Weikang Cai, Kim Cheng, Gregory J. Cooney, D. Ross Laybutt, Trina So, Juan-Carlos Molero, Shane T. Grey, Douglas A. Andres, Michael S. Rolph, Charles R. Mackay

Physiology Faculty Publications

AIMS AND HYPOTHESIS: Glucose-stimulated insulin secretion from beta-cells is a tightly regulated process that requires calcium flux to trigger exocytosis of insulin-containing vesicles. Regulation of calcium handling in beta-cells remains incompletely understood. Gem, a member of the RGK (Rad/Gem/Kir) family regulates calcium channel handling in other cell types, and Gem over-expression inhibits insulin release in insulin-secreting Min6 cells. The aim of this study was to explore the role of Gem in insulin secretion. We hypothesised that Gem may regulate insulin secretion and thus affect glucose tolerance in vivo.

METHODS: Gem-deficient mice were generated and their metabolic phenotype characterised by in …

Functional Plasticity Of Central Trpv1 Receptors In Brainstem Dorsal Vagal Complex Circuits Of Streptozotocin-Treated Hyperglycemic Mice, Andrea Zsombok, Muthu D. Bhaskaran, Hong Gao, Andrei V. Derbenev, Bret N. Smith

Physiology Faculty Publications

Emerging data indicate that central neurons participate in diabetic processes by modulating autonomic output from neurons in the dorsal motor nucleus of the vagus (DMV). We tested the hypothesis that synaptic modulation by transient receptor potential vanilloid type 1 (TRPV1) receptors is reduced in the DMV in slices from a murine model of type 1 diabetes. The TRPV1 agonist capsaicin robustly enhanced glutamate release onto DMV neurons by acting at preterminal receptors in slices from intact mice, but failed to do so in slices from diabetic mice. TRPV1 receptor protein expression in the vagal complex was unaltered. Brief insulin preapplication …