Medicine and Health Sciences Commons^™

Developing A Model To Assess The Contribution Of Cytokeratin 19-Expressing Cells During Multipotent Stromal Cell-Induced Islet Regeneration, Brianna Ananthan

Electronic Thesis and Dissertation Repository

Previously, pharmacological activation of Wnt-signaling in human bone marrow-derived multipotent stromal cells (hMSC) generated conditioned media (CM) that promoted β-cell regeneration in streptozotocin-treated mice. Ductal-derived endocrine progenitors, which have been shown to generate β-cells following pancreatic injury, represent a candidate for the ‘signal-receiving cell’. Ductal (CK19+) cells from mice pancreata obtained by purification of live Dolichos Biflorus Agglutinin lectin+ cells and cultured in minimal media supplemented with Untreated, Wnt-activated, or Wnt-inhibited CM demonstrated a significantly increased proportion of EdU+/CK19+ cells following 48-hours of supplementation but no endocrine phenotype acquisition. Lineage-tracing CK19-CreERT;Ai9(RCL-tdT) mice treated with tamoxifen (single dose) demonstrated specific labeling …

Regulation Of Glucagon Secretion And Trafficking By Proteins In The Glucagon Interactome, Farzad Asadi Jomnani

Electronic Thesis and Dissertation Repository

Patients with diabetes exhibit hyperglucagonemia, or excess glucagon secretion. The glucagonocentric hypothesis of diabetes states that hyperglucagonemia, rather than hypoinsulinemia, may be the underlying mechanism of hyperglycemia of diabetes. Thus, uncovering mechanisms that regulate glucagon secretion from pancreatic α-cells is crucial for developing treatments for hyperglycemia. One clue to the regulation of glucagon secretion may lie in the proteins that interact with glucagon in α-cell’s secretory pathway, primarily within the secretory granule. The purpose of my work was to identify proteins that interact with glucagon within the secretory granule and characterize a candidate protein within this network that regulates the …

Increased Mitochondrial Calpain-1 Is An Important Mechanism Contributing To Mitochondrial Ros Generation In Cardiac Diseases, Rui Ni

Electronic Thesis and Dissertation Repository

Both calpain activation and excessive mitochondrial reactive oxygen species (mtROS) have been implicated in the pathogenesis of cardiac diseases. We investigated whether and how calpain regulates mtROS generation in mediating cardiac diseases.

In mouse models of streptozotocin-induced type-1 diabetes and lipopolysaccharides- induced sepsis, we show that the protein levels of calpain-1 and calpain activities in mitochondria were significantly elevated in diabetic and septic hearts. The elevation of mitochondrial calpain-1 correlated with an increase in mtROS generation and oxidative damage. Importantly, cardiomyocyte-specific deletion of capns1 disrupted calpain-1 and calpain-2 in the heart and prevented mtROS generation in both septic and diabetic …

Proteomic Characterization Of Human Multipotent Stromal Cells Secreted Proteins With Therapeutic Potential For Β-Cell Regeneration, Miljan Kuljanin

Electronic Thesis and Dissertation Repository

Novel strategies to stimulate the expansion of β-cell mass in situ are warranted for diabetes therapy. Cell-replacement therapies for the treatment of diabetes have become a focal point in recent years. Endogenous regeneration of β-cell mass has been demonstrated using human multipotent stromal cells (hMSC). However, the secretory factors responsible for initiating endogenous regeneration remain unknown. Successful large-scale proteomic applications to address these questions have been limited in part by difficulties in correctly selecting the appropriate methodologies. Thus, the goal of this thesis was a combination of assessing different proteomic workflows to facilitate investigation into hMSC biology, applying these methods …

A Clinico-Pathological Study Of The Structural And Functional Changes In The Retina And Optic Nerve Following Diabetic Retinopathy Treatments, Richard Filek

Electronic Thesis and Dissertation Repository

Diabetic retinopathy (DR) is the result of microvascular changes in the retina due to hyperglycemia which alter the blood-retinal barrier (BRB). The increased permeability of BRB results in the accumulation of extracellular fluid, the development of diabetic macular edema (DME) and capillary occlusion. Capillary occlusion results in retinal ischemia which increases vascular endothelial growth factor (VEGF) levels, increases vascular permeability and results in neovascularization in proliferative diabetic retinopathy (PDR) patients. The treatments clinically used for DR are panretinal photocoagulation (PRP) for PDR and injectable vascular endothelial growth factor inhibitors (anti-VEGFs) for DME.

The safety of PRP and anti-VEGF therapy on …

Retinoic Acid Pathway Inhibition To Expand Human Hematopoietic Progenitor Cells With Islet Regenerative Capacity, Ruth Elgamal

Electronic Thesis and Dissertation Repository

Cellular therapy to induce islet regeneration is emerging as a novel treatment strategy for diabetes. Umbilical cord blood (UCB)-derived hematopoietic stem/progenitor cells (HSPC) isolated by high aldehyde dehydrogenase activity (ALDH^hi) reduce hyperglycemia after transplantation into streptozotocin (STZ)-treated NOD/SCID mice. However, UCB-derived ALDH^hi cells are rare and expansion without the loss of regenerative function is required. We hypothesized that BMS 493, an inverse retinoic acid receptor agonist, will prevent HSPC differentiation of HSPC during expansion, generating more ALDH^hi cells for therapy. ALDH^hi cells expanded for 6 days with BMS 493 showed a 2.70-fold-increase in ALDH^{hi …}

The Long Non-Coding Rna Malat1 Regulates Inflammatory Cytokine Production In Chronic Diabetic Complications, Andrew D. Gordon

Electronic Thesis and Dissertation Repository

We examined the role of MALAT1, a highly conserved nuclear lncRNA, in chronic diabetic complications affecting the heart and kidneys, specifically with respect to inflammatory cytokine production. Endothelial cells, exposed to various glucose levels, and MALAT1 knockout mice and controls, with or without streptozotocin-induced diabetes were examined. Endothelial cells cultured with high glucose, and renal and cardiac tissue from diabetic mice showed increased inflammatory cytokine (eg. IL-6, IL1β, TNFα) production along with transient MALAT1 upregulation. This was confirmed by both transcript and protein analyses, and such changes were prevented in the MALAT1 knockout diabetic animals. In the malat1 knockout animals, …

Diabetic Bone Marrow & Stem Cell Dysfunction, Meghan A. Piccinin

Electronic Thesis and Dissertation Repository

ii Abstract Abstract Defects in the proliferation, differentiation, and activity of bone marrow (BM)-derived vasculogenic/vascular stem cells (VSCs) have been observed in diabetes and contribute to the development of vascular complications. Diabetes leads to enhanced bone marrow adipogenesis, altering the composition of the BM stem cell (SC) niche and potentially disrupting the normal functioning of resident VSCs. Here, I establish that adipocytes have a negative influence on SC survival in culture. I also show that adipocytes and osteoblasts are responsible for the creation of distinct extracellular microenvironments, with unique expression patterns of several pro- and anti-angiogenic factors with known effects …

Nerve Blood Flow Control In Health & Disease:The Effects Of Type 1 Diabetes And Exercise Training, Terry D. Olver

Electronic Thesis and Dissertation Repository

Peripheral nerve blood flow (NBF) is critical to nerve health. Impaired NBF control may contribute to the progression of diabetes peripheral neuropathy. The purposes of this dissertation were: i) to investigate the acute and chronic effects of hyperglycemia on basal sciatic NBF (measured via Doppler ultrasound), ii) to examine the potential vasodilatory effects of insulin (euglycemic hyperinsulinemic clamp; 10 mµ•kg^-1•min^-1) on NBF control in healthy rats and rats with insulin-treated type 1 diabetes (DS) and iii) to determine if exercise training (~75% VO₂max, 60 min/day, 5 days/wk for 10 wk) improves vasa nervorum reactivity …

Vascular Stem Cells In Diabetic Complications, Emily C. Keats

Electronic Thesis and Dissertation Repository

Diabetes leads to a variety of secondary complications. At the heart of these complications lies endothelial cells (ECs) – cells that take up unregulated plasma glucose, experience various biochemical alterations, and provide the basis for whole organ vascular dysfunctions. With the purpose of generating new vascular networks for the treatment of these chronic complications, my initial work focused on vascular stem cells (VSCs). VSCs have the ability to differentiate into both endothelial (EPC) and mesenchymal (MPC) progenitor cells, both of which are necessary for the creation of stable and functional blood vessels. To establish whether these progenitor populations retain their …