Sex Hormones and Cerebral Endothelial Function
Date
2025
Authors
Peary, Kira
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Journal ISSN
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Publisher
University Of Victoria
Abstract
Female susceptibility to cerebrovascular disease surpasses males after menopause and it has been attributed to decreases in sex hormones such as estrogen. Estrogen promotes endothelial mediated dilation of the vasculature by activating vasoactive mediators such as nitric oxide and prostacyclin causing decreased vascular tone, therefore acting as a vascular protectant. Knowing that estrogen plays a key role in vascular function, we are interested to know its role throughout the menstrual cycle. We hypothesize that females will have more variation in their endothelial function between visits based on menstrual cycle phase, compared to males. Female and male participants aged 19-40 were recruited to complete a multi-visit protocol. Females visited in the early follicular (EF), late follicular (LF), early luteal (EL) and late luteal (LL) menstrual phases. Males completed two visits to act a sex-based comparison. On each visit, a sex hormone blood sample was collected, and subjects completed a transient hypercapnic (9% CO2) assessment to measure cerebral endothelial function. All cerebral blood flow measures were achieved using vascular duplex ultrasound. Data collection and analysis are ongoing; however, preliminary analyses (n=2 males & 2 females) indicate that females have more variation between visits in endothelial function than males. Additionally, changes in internal carotid artery diameter (ICAd) during transient hypercapnia is associated with shear rate area under the curve (SRAUC) when sex is not used as a covariate. Future analysis of sex hormones and a larger sample will enable menstrual phase comparisons in assessment of cerebral endothelial function in males and females.
Description
Keywords
cerebral blood flow, endothelial function, menstrual cycle, sex hormones, hypercapnia