School of Public Health
Permanent URI for this communityhttp://hdl.handle.net/1903/1633
The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
Note: Prior to July 1, 2007, the School of Public Health was named the College of Health & Human Performance.
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Item Effects of exercise and inflammation on circulating microparticles(2024) Heilman, James; Prior, Steven J.; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Circulating microparticles (MPs), a subset of extracellular vesicles, have been implicated as novel biomarkers connected to vascular dysfunction. As such, they may contribute to atherosclerosis, hypertension, and other conditions leading to cardiovascular disease. MPs are involved in cell-to-cell communication in response to apoptosis and activation of the immune and inflammatory response, transferring their contents to nearby cells and effectively spreading each condition. The objective of this dissertation was to explore how circulating MP number and function are affected by stimuli such as diet and exercise. Our first study examined how post-prandial inflammation caused by a high-fat meal affects circulating MP number and function in young, healthy adults. We determined that a high fitness level may have a protective effect against the inflammatory load posed by a high-fat meal. The second study determined the effects of acute high-intensity interval aerobic exercise versus acute moderate intensity continuous aerobic exercise on circulating MP number and function in overweight versus lean recreationally active adults. We found that MPs and arterial stiffness in overweight individuals are differentially impacted by the type of acute exercise. Our findings suggest that overweight individuals undergo a greater inflammatory response following high-intensity exercise compared to lean. The third study investigated the effects of a 6-month aerobic exercise training program on circulating MP counts and function in previously sedentary older adults. While we found no effect of the exercise training program on MPs, we provide insight into how improvements in cardiovascular fitness as well as higher exercise intensities may be needed to see changes in MP number and function following aerobic exercise training in older adults. For the first time, we have shown that both dietary inflammation and acute exercise can significantly impact MP function. Furthermore, we have shown that fitness status and body composition play important roles in determining MP number and function after each stimulus. Our findings provide novel insight into how MPs contribute to various types of inflammation as well as how they may be used as biomarkers to measure the progression of cardiovascular disease.Item INFLAMMATORY MACROPHAGE REGULATION OF ANGIOGENESIS AND SKELETAL MUSCLE PHENOTYPES(2023) Evans, William Stuart; Prior, Steven J; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Chronic inflammation is a hallmark of cardiovascular disease; however, there is a lack of understanding of how systemic inflammation affects the peripheral skeletal muscle to potentially hasten frailty and functional declines in patients. The overarching objective of this dissertation was to determine whether this systemic inflammation is accompanied by macrophage infiltration of skeletal muscle and reductions in skeletal muscle capillarization and fiber size. Using animal models of a) heart failure (HF) induced by transverse aortic constriction (TAC), and b) skeletal muscle ischemia, this work illuminates changes that occur in skeletal muscle with cardiovascular disease-related inflammation. The first study demonstrated that pressure overload resulted in cardiac hypertrophy in male rats consistent with heart failure with preserved ejection fraction (HFpEF), while females did not show cardiac hypertrophy or HF. The second study demonstrated sex-specific differences in skeletal muscle, with TAC male rats exhibiting smaller fiber sizes and greater capillarization, and female TAC rats exhibiting lower capillarization than Sham counterparts. This study then investigated skeletal muscle macrophages to determine whether they might underly or contribute to these differences. There were fewer macrophages in the skeletal muscle of male TAC rats than male Sham rats, and macrophage conditioned medium from TAC rats produced less-developed capillary networks in an ex vivo, experimental assay. Finally, the third study investigated whether an acute bout of systemic inflammation, in the absence of HF, could alter the infiltration of macrophages, or skeletal muscle fiber size or capillarization. Hindlimb ischemia was used to induce acute, systemic inflammation that peaked after 1 day. This systemic inflammation increased the infiltration of macrophages into remote, non-ischemic skeletal muscle by day 7; however, muscle structure was preserved over this short time course. This dissertation demonstrates that cardiovascular disease-associated inflammation is linked with tissue-level changes in macrophages in a sex-specific manner. These changes accompany and may, over time, contribute to skeletal muscle fiber atrophy and changes in capillarization in cardiovascular disease patients.Item SIMILAR VASCULAR RESPONSES TO A HIGH-FAT MEAL, REGARDLESS OF RACE AND SOCIAL DETERMINANTS OF HEALTH(2022) Weiner, Cynthia Marie; Ranadive, Sushant M; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Black individuals are at a higher risk for developing cardiovascular disease (CVD), including hypertension, compared to white individuals. Chronic low-grade inflammation contributes to hypertension by causing vascular dysfunction, including increased vascular resistance. Young, healthy, normotensive black individuals exhibit heightened inflammatory biomarkers at rest, a possible factor in the higher prevalence of hypertension seen within this population. Vascular function decreases transiently as a result of an acute inflammatory stimulus, such as with consumption of a high-fat meal (HFM). However, there is limited evidence regarding the racial differences in inflammatory and vascular responses to a HFM in young, healthy black and white individuals. Furthermore, there are limited data regarding the association between social determinants of health (SDH) factors and the physiological components of inflammation and vascular responses. Therefore, the goal of the present study was twofold: to evaluate the racial differences in inflammatory and vascular responses to a HFM and to evaluate the potential impact of SDH factors on these relationships. Five black individuals (5 males, 21.2 ± 1.5 yrs) and 14 white individuals (7 males/7 females, 25 ± 4.1 yrs) completed the study. White individuals were significantly older than black individuals, but were similar in fitness status (VO2peak; 43.4 ± 10.8 ml/kg/min vs. 40.5 ± 5.9 ml/kg/min) and BMI (22.6 ± 2.9 kg/m2 vs. 23.5 ± 3.3 kg/m2). Black and white individuals exhibited similar vascular function, arterial stiffness, wave reflection, and hemodynamic variables (BP, HR) at baseline and following the HFM. Black individuals had a significantly lower total SDH score compared to white individuals, indicating lower SDH across seven domains assessed in the SDH questionnaire. However, SDH was not associated with any of the vascular measurements at baseline or following the HFM. Inflammation was not detected at baseline and following the HFM, as measured by a multiplex immunoassay. Therefore young, healthy black and white individuals maintain vascular function following a HFM, regardless of SDH status.Item INVESTIGATING CARDIOVASCULAR RISK AT THE INTERSECTION OF RACE, GENDER, AND EDUCATION(2019) Taiwo, Omolola Tanya; Boekeloo, Bradley O; Public and Community Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)As a risk factor of cardiovascular disease (CVD), systemic inflammation is differentially distributed by race, with black populations disproportionately impacted. Additionally, inflammation, as measured by the inflammatory marker C-reactive protein (CRP), is documented to be higher among women when compared to men and varies by educational level. Despite evidence suggesting that various chronic stress domains may contribute to the relationship between race and inflammation, there is limited data exploring the possible mediating role of chronic stress. Furthermore, to date, no study has examined if the potential indirect effect of race on CRP through chronic stress domains are moderated by gender and education. This secondary data analysis stems from the Midlife Development in the United States (MIDUS II) study, and the sample consisted of 193 black and 582 white adults. Study 1: Examined the association between CRP and seven racial/gender/education subgroups. With educated white men as the reference group, findings revealed that educated black and white women had the highest significant risk for elevated CRP. Study 2: Assessed the psychometric properties of a Chronic Stress Scale (CSS) comprised of nine chronic stress subscales. Analyses revealed CSS to be a three-dimensional scale with questionable validity and reliability. Study 3: First, tested for significant correlations between nine chronic stress domains, race, and CRP. Everyday discrimination and financial strain were found to be the only two domains significantly correlated to race and CRP. Second, two mediation analyses assessed the mediating effect of financial strain and discrimination, finding that they both respectively mediated the relationship between race and CRP. Third, two moderated mediation analyses examined if the indirect effect of financial strain and discrimination were moderated by gender and education. Results indicated that the indirect effect of race on CRP through discrimination was significant only among educated black men. Additionally, findings revealed that the indirect effect of race on CRP through financial strain was significant among black men and women regardless of educational attainment. Combined, these studies characterized the social patterning of CRP, illustrated validity and reliability concerns when developing a multidimensional chronic stress scale, and revealed that discrimination and financial strain did have mediating roles and these mediators were moderated by gender and education.Item Maternal experiences of intimate partner violence and C-reactive protein levels in young children in Tanzania(Elsevier, 2018-12) Slopen, Natalie; Zhang, Jing; Urlacher, Samuel S.; De Silva, Gretchen; Mittal, MonaIntimate partner violence (IPV) is a critical public health issue that impacts women and children across the globe. Prior studies have documented that maternal experiences of IPV are associated with adverse psychological and physical health outcomes in children; however, research on the underlying physiological pathways linking IPV to these conditions is limited. Drawing on data from the 2010 Tanzania Demographic and Health Survey, we examined the relationship between maternal report of IPV in the past 12 months and inflammation among children ages 6 months to 5 years. Our study included 503 children who were randomly selected to provide a blood sample and had a mother who had ever been married and who had completed the Domestic Violence Module, which collected information on physical, sexual, and emotional violence. Analyses were stratified based on a threshold for acute immune activation status, defined by the threshold of CRP>1.1 mg/L for young children in Tanzania. In bivariate analyses, healthy children whose mothers reported IPV showed a marginally elevated median CRP level compared to children whose mothers did not report IPV (0.35 vs. 0.41 mg/L; p = 0.13). Similarly, among children with active or recent infections, those whose mothers reported IPV had an elevated median CRP compared to children whose mothers did not (4.06 vs 3.09 mg/L; p = 0.03). In adjusted multiple variable regression models to account for child, mother, and household characteristics, maternal IPV was positively associated with (log) CRP in both healthy children and children with active or recent infection. Although longitudinal research with additional biomarkers of inflammation is needed, our results provide support for the hypothesis that inflammation may function as a biological pathway linking maternal IPV to poor psychological and physical health outcomes among children of mothers who are victimized—and this may extend to very young children and children in non-Western contexts.Item Association Between C-Reactive Protein and Serum 25-Hydroxyvitamin D: A Negative Acute Phase Reactant(2015) Verdin, Kelly; Lee, Sunmin; Epidemiology and Biostatistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Objective: The aims of this study were to determine whether serum 25-hydroxyvitamin-D (25-OH-vitamin D) is a negative acute phase reactant and whether class of diagnosis modifies the association between C-Reactive Protein (CRP) and 25-OH-vitamin D. Methods: Multiple linear regression analysis was utilized to assess the association between CRP and 25-OH-vitamin D in 1,043 patients with acute and chronic diseases and normal volunteers. Results: After adjusting for confounding factors, the association between CRP and 25-OH-vitamin D was statistically significant. Class of diagnosis did not modify this association. Conclusions: 25-OH-vitamin D is demonstrated to be a negative acute phase reactant in this group of patients; Therefore, it is not an accurate marker of vitamin D status in the setting of inflammation. These findings support that 25-OH-vitamin D should be interpreted cautiously when CRP is elevated and that evaluating 25-OH-vitamin D in the context of CRP will improve accuracy of 25-OH-vitamin D interpretation.