ORCID Identifier(s)

0000-0003-0172-9154

Graduation Semester and Year

2021

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Kinesiology

Department

Kinesiology

First Advisor

Matthew R. Brothers

Abstract

Cardiovascular diseases (CVD), including hypertension, disproportionately affect the non-Hispanic black (BL) population in the United States. Despite being an inherently multifactorial process, altered vascular function remains a critical hallmark in the development of CVD. Further, blunted vascular function is often observed in the BL population. Recent advancements have linked several observational and mechanistic findings to the reduced vascular function in BL individuals, though the breadth of functional disparities in this population, the mechanistic contributors to these differences across sexes, and possible interventions to improve vascular function remain unelucidated. Therefore, this dissertation aimed to expand our current understanding of the vascular contributors to CVD risk in the BL population. Study 1 provided observational evidence of divergent vascular function across the peripheral and cerebral circulations in young, BL men and women, highlighting a crucial role of sex in the presentation of blunted vascular function and, perhaps, the development of CVD. Study 2 utilized intradermal microdialysis to assess the mechanisms of blunted microvascular function in young, BL women. In this study, our data suggest that endothelin-1 (ET-1), acting primarily through ET-1 receptor type A, partially restrained vasodilation during local heating-induced cutaneous hyperemia through a nitric oxide-dependent mechanism. Further, these data suggest that neither supplemental L-arginine nor ET-1 receptor type B antagonism improved cutaneous microvascular function. Finally, Study 3 aimed to compare the hemodynamic and cardiovascular responses to mental stress in young, BL and non-Hispanic white (WH) men and determine if acute nitrate supplementation could improve these hemodynamic and cardiovascular responses in the BL men. Indeed, the BL men possessed blunted hemodynamic and cardiovascular responses to mental stress relative to the WH men. Despite this blunting, a single dose of nitrate was not substantial enough to modify these responses. The research described herein represents essential steps in our understanding of disparate vascular function in the BL population. Perhaps more importantly, this research also clarifies the role of sex and potential treatment approaches related to vascular function and CVD risk within the BL population. Therefore, future research on these topics may leverage these findings to target additional candidate mechanisms and therapies to lessen the burden of CVD in the BL population.

Keywords

Cardiovascular diseases, Non-Hispanic black individuals, Vascular function, Nitric oxide, Health disparities

Disciplines

Kinesiology | Life Sciences

Comments

Degree granted by The University of Texas at Arlington

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