Estrogen upregulation of VEGF receptors on human microvascular endothelial cells is associated with estrogen receptor-α expression

Estrogen has vascular effects but its action in human microvascular endothelial cells (MEC) has not been elucidated. The aims of this study were to determine if estrogen (E) upregulates VEGF receptor expression in MEC and establish whether this effect was related to estrogen receptor (ERalpha /or ERbeta) expression. E significantly increased VEGF binding to human myometrial MEC between 3-18 hr and was maximal between 0.1-10 nmol/L E. This response occurred in 60% of samples and was blocked by the ER antagonist, ICI 182,780. Myometrial MEC expressed ERbeta constitutively, but ERalpha was only expressed in 13/21 samples. There was a significant association between ERalpha expression and the ability of myometrial MEC to respond to E by upregulating VEGF receptors (P < 0.05), suggesting that this effect is variable and may be mediated by ER alpha.