Role of Angiotensin II and Chronic Inflammation in Persistent Microvascular Dysfunction Following Preeclamptic Pregnancy

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Project Summary/Abstract Otherwise healthy women who develop preeclampsia during pregnancy are at a significantly (2-4 times) greater risk for cardiovascular disease (CVD) morbidity and mortality; however, the mechanism(s) responsible for this association remain unclear. One emerging hypothesis for this association is chronically elevated inflammation and irreversible endothelial damage sustained during the preeclamptic pregnancy that persist postpartum. In support of this hypothesis, healthy women with a history of preeclampsia demonstrate elevated inflammatory cytokines, as well as increased vasoconstrictor sensitivity to angiotensin II (ang II) and attenuated endothelium-dependent vasodilation. Further, compelling data from rodent models suggest that potentiated signaling between ang II and inflammatory mediators contribute to severe vessel dysfunction during a preeclamptic pregnancy. Taken together, these data suggest that chronic changes in ang II and inflammatory signaling may lead to a pro-constrictor milieu in which attenuated endothelium-dependent vasodilation, reduced nitric oxide bioavailability, and exaggerated vasoconstriction result in persistent vessel dysfunction in women who have had preeclampsia. However, few, if any, in vivo studies have sought to investigate these mechanisms in humans. Using an innovative translational human approach that combines 1) in vivo pharmaco- dissection of mechanisms of vascular dysfunction, 2) in vitro measures of immune cell activity, and 3) both acute and chronic pharmacological treatments, the overarching goal of the proposed studies is a comprehensive mechanistic examination of aberrant ang II signaling and chronic inflammation - including novel interventional pathways - in otherwise healthy women who have had preeclampsia. In specific aim 1 we will define the mechanistic role of ang II signaling in microvascular inflammation and associated endothelial dysfunction in women who have had preeclampsia compared to control women who have had a healthy pregnancy. In specific aim 2 we will define the mechanistic anti-inflammatory role of angiotensin 1-7 (an endogenous inhibitor of ang II signaling). In specific aim 3 we will determine the effect of systemic ang II type 1 receptor inhibition (chronic oral losartan therapy) on in vivo and in vitro measures of inflammation and endothelial function in women who have had preeclampsia. This comprehensive assessment of mechanisms mediating persistent microvascular dysfunction, and the identification of novel mechanisms by which to mitigate this dysfunction, directly translates functional and molecular findings of cell and animal studies to a clinical population and will lend insight into the management of chronic elevated CVD risk in women who have had preeclampsia. These projects will extend the applicant’s training in integrative cardiovascular physiology by allowing her to acquire new technical skills, including in vitro biochemical analysis of human peripheral blood mononuclear cells, while simultaneously providing strong mentored training and professional development, tailored to transition the PI to independence.