Angiogenesis mediators in women with idiopathic heavy menstrual bleeding

Estrogens Regulate Placental Angiogenesis in Horses

A sufficient vascular network within the feto-maternal interface is necessary for placental function. Several pregnancy abnormalities have been associated with abnormal vascular formations in the placenta. We hypothesized that growth and expansion of the placental vascular network in the equine (Equus caballus) placenta is regulated by estrogens (estrogen family hormones), a hormone with a high circulating concentration during equine gestation. Administration of letrozole, a potent and specific inhibitor of aromatase, during the first trimester (D30 to D118), decreased circulatory estrone sulfate concentrations, increased circulatory testosterone and androstenedione concentrations, and tended to reduce the weight of the fetus (p < 0.1). Moreover, the gene expression of CYP17A1 was increased, and the expression of androgen receptor was decreased in the D120 chorioallantois (CA) of letrozole-treated mares in comparison to that of the control mares. We also found that at D120, the number of vessels tended to decrease in the CAs with letrozole treatment (p = 0.07). In addition, expression of a subset of angiogenic genes, such as ANGPT1, VEGF, and NOS2, were altered in the CAs of letrozole-treated mares. We further demonstrated that 17β-estradiol increases the expression of ANGPT1 and VEGF and increases the angiogenic activity of equine endothelial cells in vitro. Our results from the estrogen-suppressed group demonstrated an impaired placental vascular network, suggesting an estrogen-dependent vasculogenesis in the equine CA during the first trimester.

17β-Estradiol Promotes Angiogenesis of Rat Cardiac Microvascular Endothelial Cells In Vitro

Background

The formation of new blood vessels, known as angiogenesis, is critical for recovery from ischemic heart disease, and estrogen is considered an important factor in this process. Here, we investigated the effects of 17β-estradiol (17β-E₂) on proliferation and migration of cardiac microvascular endothelial cells (CMECs) in vitro.

Material/Methods

Rat CMECs were isolated and cultured with 17β-E2 (0.001–1 μmol/l) in the absence or presence of the estrogen antagonist tamoxifen. Then, the expression level of estrogen receptor alpha was evaluated by using immunofluorescence assay, RT-PCR, and Western blot. Cell proliferation was detected by methyl thiazolyl tetrazolium analysis and the cell migration was verified by a scraping assay and quantified by a Transwell chamber assay. CMEC differentiation was examined using a tube formation assay. Vascular endothelial growth factor (VEGF) secretion was detected by enzyme-linked immunosorbent assay.

Results

CMECs exhibited homogenous, polygonal, exhibited contact inhibition, and had characteristically ovoid nuclei with 1 or 2 nucleoli, and the cytoplasm exhibited red fluorescence after staining for von Willebrand factor. 17β-E2 treatment upregulated estrogen receptor alpha expression in CMECs. 17β-E2 treatment significantly promoted the proliferation, migration, tubular structure formation, and VEGF secretion in CMECs. The maximal proliferation occurred in the presence of 0.01 μmol/l 17β-E2. Furthermore, estrogen and VEGF were found to synergistically stimulate angiogenesis.

Conclusions

Our data show that 17β-E2 promotes angiogenesis in vitro and suggests that estrogen treatment as a novel therapeutic modality in the management of arterial insufficiency.