Heterogeneity of estrogen and β-adrenergic receptors in female human coronary artery endothelial cells.

Introduction: Estrogen protects vascular function, likely via adrenergic modulation. Previous studies of estrogen and beta-adrenoceptor (β-AR) interactions relied on non-coronary or animal models, limiting relevance to human coronary endothelium. This study aimed to characterize estrogen receptor (ER) and β-AR expression in human coronary artery endothelial cells (HCAECs), evaluate inter-donor variability, and determine whether ER stimulation alters β-AR gene expression. Methods: HCAECs from female donors were analyzed for expression of ERs (ERα, ERβ, GPER), and β-ARs (β Results: Immunofluorescence revealed presence of all three ERs and β-ARs in the HCAECs. ERα had the lowest mRNA expression, while GPER was the most abundant, with donor-dependent variability. ERβ and GPER proteins were slightly higher than ERα. β Conclusion: These findings demonstrate donor variability in ER and β-AR expression in HCAECs, limiting generalization. Under the tested conditions estrogen and ER agonists did not alter β-AR mRNA levels, suggesting that short-term ER stimulation is unlikely to regulate β-AR expression at the transcriptional level within this experimental setting.