Matching Items (6)
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- All Subjects: inflammation
- All Subjects: Hypertension
- Creators: Sweazea, Karen
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
Description
There has long been a link tied between obesity and such pathological conditions as nonalcoholic fatty liver disease and type two diabetes. Studies have shown that feeding rats a diet high in fat results in hepatic steatosis and steatohepatitis. Using a novel short term diet of six weeks with male adolescent Sprague-Dawley rats, our laboratory sought to investigate the early effects of high fat intake on the liver. Prior findings in our laboratory found that a high fat diet (HFD) leads to nonalcoholic fatty liver disease as well as other symptoms of metabolic syndrome. This study hypothesized that rats fed a 60% HFD for 6 weeks, unlike a high sucrose or standard chow diet, would have an elevated expression of pro-inflammatory cytokines associated with steatohepatitis. TNF-α, TLR4 and XBP1 were chosen for their link to hepatic inflammation. The results of this study found that contrary to the hypothesis, the high fat diet did not induce significant changes in the expression of any inflammatory marker in comparison to a high sucrose or control chow diet.
ContributorsCalhoun, Matthew (Author) / Sweazea, Karen (Thesis director) / Deviche, Pierre (Reviewer) / Barrett, The Honors College (Contributor)
Created2015-05
Description
Birds have unusually high plasma glucose concentrations compared to mammals of similar size despite their high metabolic rate. While birds use lipids as their main source of energy, it is still unclear how and why they maintain high plasma glucose concentrations. To investigate a potential underlying mechanism, this study looks at the role of lipolysis in glucose homeostasis. The purpose of this study is to examine the effects of decreased glycerol availability (through inhibition of lipolysis) on plasma glucose concentrations in mourning doves. The hypothesis is that decreased availability of glycerol will result in decreased production of glucose through gluconeogenesis leading to reduced plasma glucose concentrations. In the morning of each experiment, mourning doves were collected at the Arizona State University Tempe campus, and randomized into either a control group (0.9% saline) or experimental group (acipimox, 50mg/kg BM). Blood samples were collected prior to treatment, and at 1, 2, and 3 hours post-treatment. At 3 hours, doves were euthanized, and tissue samples were collected for analysis. Acipimox treatment resulted in significant increases in blood glucose concentrations at 1 and 2 hours post- treatment as well as renal triglyceride concentrations at 3 hours post-treatment. Change in plasma free glycerol between 0h and 3h followed an increasing trend for the acipimox treated animals, and a decreasing trend in the saline treated animals. These results do not support the hypothesis that inhibition of lipolysis should decrease blood glycerol and blood glucose levels. Rather, the effects of acipimox in glucose homeostasis appear to differ significantly between birds and mammals suggesting differing mechanisms for glucose homeostasis.
ContributorsKouteib, Soukaina (Author) / Sweazea, Karen (Thesis director) / Deviche, Pierre (Committee member) / Chandler, Douglas (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Vascular inflammation is a key component for cerebrovascular disease and ischemic injury is suggested to be a significant contributor, resulting in either myocardial ischemia or stroke. A strong inflammatory response is characterized by the release of inflammatory cytokines, thus producing and/or activating pro-inflammatory proteins in the cell. Our previous studies have demonstrated that hypoxia plus glucose deprivation (HGD), an in vitro model of ischemia, increases the proinflammatory mediator, cyclooxygenase-2 levels (COX-2), in vascular tissues. Nuclear factor kappa B (NF-κB) activation is an upstream transcription factor of COX-2 and had been suggested to be involved in “sterile” inflammation in experimental stroke models. Mechanisms underlying the development and progression of inflammation in the cerebrovasculature following ischemic injury in human tissue has not been addressed. Thus, the purpose of this study was to examine the impact of HGD on NF-κB expression and activation in human brain vascular smooth muscle cells (HBVSMC). In addition, we assessed pro-inflammatory mediator levels of downstream NF-κB transcription products, COX-2 and iNOS, and level of its upstream receptor, TLR4. Primary HBVSMC at passage 7 were treated with normoxia (room air) or HGD (1% O2). Following exposure to HGD (3h), cells were isolated, homogenized, and total protein content determined. Lysates, either whole cell or nuclear and cytosolic fractions, were prepped for western blot and analysis. Anti-α-smooth muscle actin was used to verify HBVSMC origin and -actin was used as a loading control. NF-κBp65, phosphorylated NF-κBp65, COX-2, and TLR4 protein levels were all measured post HGD. NF-κBp65 total protein was expressed in HBVSMC and a trend for an increase in levels following HGD was observed. Indirect activation of pNF-kBp65 was assessed via nuclear fractionation studies and was increased following HGD. Lamin AC was used to verify nuclear fractionation. Additional findings suggested that HBVSMC expressed TLR4 however, total protein levels of TLR4 were not altered by HGD. COX-2 and iNOS protein levels were also increased following HGD. In conclusion, these studies indicate that HGD alters proinflammatory enzyme levels, potentially by altering NF-κBp65 activation in human vascular smooth muscle cells. Funding Support: University of Arizona Sarver Heart Center and University of Arizona Valley Research Project Grant VRP P1 (RG).
ContributorsRahman, Sanna (Author) / Sweazea, Karen (Thesis director) / Gonzales, Rayna (Committee member) / Li, Yu-Jing (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
Vascular inflammation plays a key role in the development and progression of cardiovascular disease. High fat diet has been associated with cardiovascular risk (1). Therefore, as poor nutrition and poor diet become more widespread, the number of people at risk to cardiovascular disease increases. We hypothesized that using the cancer drug lenalidomide would reverse the inflammation caused by high fat conditions. Human aortic vascular smooth muscle cells were used as an in vitro model to analyze the effect of lenalidomide on high fat diet induced inflammation. Palmitate, a saturated fatty acid was used to induce inflammation. Since lenalidomide has been shown to inhibit cytokine production and attenuate oxidative stress, we investigated whether lenalidomide alters select markers of vascular inflammation in vascular smooth muscle treated with high fat exposure using palmitate. These markers were cyclooxygenase-2 (COX-2) protein levels, TNF-α pro-inflammatory cytokine levels, and superoxide ions. Lenalidomide (5 µM) reversed COX-2 protein expression in cells exposed to high fat conditions (100 µM palmitate). In conclusion, high fat exposure elicits an inflammatory response in cultured primary human vascular smooth muscle, but this response appears to be independent of local cytokine or ROS production. Lenalidomide, although effective at reversing palmitate-induced COX-2, alone augments the pro-inflammatory mediators, COX-2 and TNF-α as well as promotes oxidative stress independent of high fat exposure in human vascular smooth muscle cells.
ContributorsBartel, Robyn Katherine (Author) / Sweazea, Karen (Thesis director) / DeCourt, Boris (Committee member) / Gonzales, Rayna (Committee member) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
Reducing the amount of error and introduced data variability increases the accuracy of Western blot results. In this study, different methods of normalization for loading differences and data alignment were explored with respect to their impact on Western blot results. GAPDH was compared to the LI-COR Revert total protein stain as a loading control. The impact of normalizing data to a control condition, which is commonly done to align Western blot data distributed over several immunoblots, was also investigated. Specifically, this study addressed whether normalization to a small subset of distinct controls on each immunoblot increases pooled data variability compared to a larger set of controls. Protein expression data for NOX-2 and SOD-2 from a study investigating the protective role of the bradykinin type 1 receptor in angiotensin-II induced left ventricle remodeling were used to address these questions but are also discussed in the context of the original study. The comparison of GAPDH and Revert total protein stain as a loading control was done by assessing their correlation and comparing how they affected protein expression results. Additionally, the impact of treatment on GAPDH was investigated. To assess how normalization to different combinations of controls influences data variability, protein data were normalized to the average of 5 controls, the average of 2 controls, or an average vehicle and the results by treatment were compared. The results of this study demonstrated that GAPDH expression is not affected by angiotensin-II or bradykinin type 1 receptor antagonist R-954 and is a less sensitive loading control compared to Revert total protein stain. Normalization to the average of 5 controls tended to reduce pooled data variability compared to 2 controls. Lastly, the results of this study provided preliminary evidence that R-954 does not alter the expression of NOX-2 or SOD-2 to an expression profile that would be expected to explain the protection it confers against Ang-II induced left ventricle remodeling.
ContributorsSiegel, Matthew Marat (Author) / Jeremy, Mills (Thesis director) / Sweazea, Karen (Committee member) / Hale, Taben (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Birds maintain resting plasma glucose concentrations (pGlu) nearly twice that of comparably sized mammals. Despite this, birds do not incur much of the oxidative tissue damage that might be expected from a high pGlu. Their ability to stave off oxidative damage allows birds to serve as a negative model of hyperglycemia-related complications, making them ideal for the development of new diabetes treatments with the potential for human application. Previous studies conducted by the Sweazea Lab at Arizona State University aimed to use diet as a means to raise blood glucose in mourning doves (Zenaida macroura) in order to better understand the mechanisms they utilize to stave off oxidative damage. These protocols used dietary interventions—a 60% high fat (HF) “chow” diet, and a high carbohydrate (HC) white bread diet—but were unsuccessful in inducing pathologies. Based on this research, we hypothesized that a model of an urban diet (high in fat, refined carbohydrates, and sodium) might impair vasodilation, as the effect of this diet on birds is currently unknown. We found that tibial vasodilation was significantly impaired in birds fed an urban diet compared to those fed a seed diet. Unexpectedly, vasodilation in the urban diet group was comparable to data of wild-caught birds from previous research, possibly indicating that the birds had already been eating a diet similar to this study’s urban diet before they were caught. This may constitute evidence that the seed diet improved vasodilation while the urban diet more closely mimicked the diet of the birds before the trial, suggesting that the model of the urban diet acted as the control diet in this context. This study is the first step in elucidating avian mechanisms for dealing with diabetogenic diets and has potential to aid in the development of treatments for humans with metabolic syndrome.
ContributorsRenner, Michael William (Author) / Sweazea, Karen (Thesis director) / Johnston, Carol (Committee member) / Basile, Anthony (Committee member) / Dean, W.P. Carey School of Business (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05