Abstract 17462: Relevance of Regulatory T Cells to Gender Dimorphism in Pulmonary Hypertension

Idiopathic Pulmonary Arterial Hypertension (IPAH) is a disease with female predominance. A growing body of evidence shows reciprocal relationship between sex steroids and the immune system. The aim of the present study was to determine whether the absence of Tregs with the presence of endogenous estrogen mediate the development of PH in a gender-specific manner and if protective signaling pathways of Tregs prevent gender dimorphism of PH susceptibility in T cell deficient animal model of PH. Methods and Results: in two utilized models of PH inbred Wag T cell deficient athymic (AT) nude male and female rats were given s/c SU5416 in normoxia or treated with chronic hypoxia (CH) for 21d. In IR experiments, AT rats received purified CD4+CD25+hi/Tregs. We also tested the effect of murine/human Tregs or CD4+CD25- on primary rat lung, cardiac and human lung microvascular ECs (RLMECs, HLMECs, RCMECs) with set-up of cocultures. In both PH models treatment resulted in development of PH with significantly higher RVS...