Racial differences in the responses to shear stress in human umbilical vein endothelial cells
Cell Culture Techniques
European Continental Ancestry Group
Human Umbilical Vein Endothelial Cells
Nitric Oxide Synthase Type III
Permanent link to this recordhttp://hdl.handle.net/20.500.12613/5521
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AbstractBackground: African American ethnicity is an independent risk factor for exaggerated oxidative stress, which is related to inflammation, hypertension, and cardiovascular disease. Recently, we reported that in vitro oxidative stress and inflammation levels differ between African American and Caucasian human umbilical vein endothelial cells (HUVECs), African American HUVECs having higher levels of both. However, it remains to be shown whether the cells would respond differently to external stimuli. Methods: We used a cone and plate viscometer to apply laminar shear stress (LSS) as an aerobic exercise mimetic to compare the responses by race. HUVECs were exposed to static conditions (no LSS), low LSS (5 dyne/cm2), and moderate LSS (20 dyne/cm2). Results: It was found that African American HUVECs had higher levels of oxidative stress under static conditions, and when LSS was applied protein expression levels (NADPH oxidase NOX2, NOX4 and p47phox subunits, eNOS, SOD2, and catalase) and biomarkers (NO, SOD, and total antioxidant capacity) were modulated to similar levels between race. Conclusion: African American HUVECs may be more responsive to LSS stimulus indicating that aerobic exercise prescriptions may be valuable for this population since the potential exists for large in vivo improvements in oxidative stress levels along the endothelial layer in response to increased shear flow. © 2011 Feairheller et al, publisher and licensee Dove Medical Press Ltd.
Citation to related workInforma UK Limited
Has partVascular Health and Risk Management
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Race-Dependent Modulation of Endothelial Cell Responses to Shear Stress: Implications for Vascular Health in African AmericansBrown, Michael D.; Park, Joon Young; Rizzo, Victor; Kendrick, Zebulon V.; Roth, Stephen M., 1973- (Temple University. Libraries, 2011)It is known that African American ethnicity is an independent risk factor for exaggerated oxidative stress which is intricately intertwined with inflammation, hypertension (HT), and cardiovascular disease (CVD). The purpose of this dissertation study was to examine the racial differences that exist between African Americans and Caucasians in oxidative stress levels at the molecular level using an in vitro model of Human Umbilical Vein Endothelial Cells (HUVECs). African American HUVECs were found to have significantly higher baseline levels of oxidative stress in vitro compared to Caucasian HUVECs. In order to establish proof of concept, three preliminary studies were conducted. The first preliminary study, an acute exercise protocol was conducted in young healthy adults in order to measure plasma oxidative stress markers in response to a single moderate intensity treadmill exercise bout. In this study, it was found that the treadmill exercise did not elicit a race-dependent responses, but that African American adults had higher level of oxidative stress at all sample times when compared to the Caucasians. A second preliminary study was conducted using a parallel cell culture design to measure basal oxidative stress levels in African American and Caucasian HUVECs without stimulation. These data were shown in relation to the plasma levels of oxidative stress in resting African American and Caucasian adults. This was done in order to show that the common oxidative stress markers measured in human plasma can also be measured in cell culture supernatant and lysate. It was found that both African American adults and HUVECs had heightened oxidative stress and inflammatory markers when compared to their Caucasian counterparts. The third preliminary study was conducted using tumor Necrosis Factor-#945; (TNF-#945;) as an inflammatory stimulant and measuring the oxidative stress response in both African American and Caucasian HUVECs. This was done in order to show that cells of different race respond differently to stimuli. It was found that the response to TNF-α was blunted in African American HUVECs. The final step was to use laminar shear stress (LSS) as an exercise mimetic in order to examine whether HUVECs from different race respond differently. HUVECs from both race were harvested under static condition (no LSS), with low LSS at 5 dyne/cm2, and with a moderate level of LSS at 20 dyne/cm2. It was found that despite the fact that African American HUVECs had higher levels of oxidative stress under static conditions, when LSS was applied, protein expressions and oxidative stress biomarkers adjusted to levels that were similar to the Caucasian HUVEC adaptations to LSS. From this, it appears that African American HUVECs have a larger response to LSS stimulus indicating that aerobic exercise prescriptions may be valuable for this population since the potential exists for large improvements in oxidative stress levels for this population.
A Test of Vulnerability-Specific Stress GenerationAlloy, Lauren B.; Drabick, Deborah A.; Giovannetti, Tania; Heimberg, Richard G.; McCloskey, Michael S.; Klugman, Joshua (Temple University. Libraries, 2011)Although there is a substantial amount of evidence documenting the stress generation effect in depression (i.e., the tendency for depression-prone individuals to experience higher rates of stressful life events that are in part influenced by the individual), additional research is required to elucidate its underlying mechanisms as well as to advance current understanding of the specific types of dependent life stresses (i.e., events influenced by characteristics and attendant behaviors of the individual) relevant to this effect. The present study proposed an extension of the stress generation hypothesis, in which the content of dependent stresses that are produced by depression-prone individuals is contingent upon, and matches, the nature of their particular vulnerability. This extension was tested within the context of the hopelessness theory of depression (Abramson, Metalsky, & Alloy, 1989) and Cole's (1990, 1991) competency-based model of depression. Also assessed were the specificity of excessive reassurance-seeking and negative feedback-seeking to stress generation in social domains and as potential mediators or moderators of the relation between cognitive vulnerability and dependent stress. General support was found for vulnerability-specific stress generation. Specifically, in analyses across vulnerability domains, evidence of relational specificity was found for all domain-specific cognitive vulnerabilities with the exception of self-perceived social competence. In analyses within cognitive vulnerability domains, support for the specificity hypothesis was found for self-perceived competence in academic and appearance domains. The within-domain analyses for negative inferential styles in achievement, interpersonal, and appearance domains produced more mixed results, but were largely supportive. Additionally, excessive reassurance-seeking was found specifically to predict dependent stress in the social domain, and moderated, but did not mediate, the relation between negative inferential styles overall and in the interpersonal domain and their corresponding generated stress. Finally, no evidence was found for a stress generation effect with negative feedback-seeking.
Challenges Experienced by Older People During the Initial Months of the COVID-19 PandemicSiminoff Research Group (Temple University) (2020-09-21)Background and Objectives: The coronavirus disease 2019 (COVID-19) pandemic has created unique stressors for older people to manage. Informed by the Stress Process Model and the Transactional Model of Stress and Coping, we examined the extent to which older people are adhering to physical distancing mandates and the pandemic-related experiences that older people find most challenging. Research Design and Methods: From May 4 to May 17, 2020, a web-based questionnaire focused on the COVID-19 pandemic was completed by 1,272 people (aged 64 and older) who were part of an ongoing research panel in New Jersey recruited in 2006. Frequencies for endorsement of physical distancing behaviors were tabulated, and open-ended responses to the biggest challenge of the pandemic were systematically coded and classified using content analysis. Results: More than 70% of participants reported adhering to physical distancing behaviors. Experiences appraised as most difficult by participants fell into 8 domains: Social Relationships, Activity Restrictions, Psychological, Health, Financial, Global Environment, Death, and Home Care. The most frequently appraised challenges were constraints on social interactions (42.4%) and restrictions on activity (30.9%). Discussion and Implications: In the initial weeks of the pandemic, the majority of older adults reported adhering to COVID-19 physical distancing mandates and identified a range of challenging experiences. Results highlight the factors having the greatest impact on older adults, informing quantitative modeling for testing the impact of the pandemic on health and well-being outcomes, and identifying how intervention efforts may be targeted to maximize the quality of life of older adults.