Effects of Endocrine Disrupting Chemicals on Human Endometrial Endothelial Cells In Vitro

Helmestam, M. 2013. Effects of Endocrine Disrupting Chemicals on Human Endometrial Endothelial Cells In Vitro. Acta Universitatis Upsaliensis. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine 902. 70 pp. Uppsala. ISBN 978-91-554-8663-1. Evidence from an abundant number of studies suggests that human female reproductive functions have become impaired over the past half century and that there might be a relationship between endocrine disrupting chemicals (EDCs) and reduced fertility. It is, however, not known by what mechanisms EDCs affect different reproductive functions such as endometrial receptivity, embryo implantation and placentation. The endometrium is continuously changing its morphological and functional properties, responding to cyclic changes of oestrogen and progesterone levels during the menstrual cycle. These changes include monthly preparation for embryo implantation through changed endometrial angiogenic activity and consequent changes in endometrial vasculature. Use of primary human endometrial endothelial cells (HEECs) in this work was evaluated as a possible screening tool for effects caused by EDCs on human endometrial vasculature and subsequently on various endometrial functions. In this study HEEC and endometrial stromal cells were isolated. HEECs were grown in monocultures, and together with stromal cells in co-cultures, and exposed to endocrine active substances. These were cadmium, which has oestrogenic properties, tamoxifen, with antioestrogenic effects, mifepristone, which is an anti-progestin, and bisphenol A, with oestrogenic properties. The effects were evaluated by using proliferation and viability assays, migration and tube formation assays, quantitative PCR (qPCR), immunohistochemistry and western blot. Cadmium affected the expression of angiogenesis-related genes, and caused different effects in HEECs cultured alone vs. HEECs co-cultured with stromal cells. Tamoxifen altered the expression of angiogenesis-related genes and reduced HEEC migration, thus having an anti-angiogenic effect. Mifepristone caused reduced formation of tubular structures in tubeformation assays involving HEECs co-cultured with stromal cells. Bisphenol A promoted tube formation in co-cultured HEECs which was related to changes in the expression of several angiogenesis-related genes as well as up-regulated expression of VEGF-D protein. In conclusion, we showed that EDCs have the ability to induce changes in endometrial angiogenic activity in vitro and may thus disturb normal endometrial functions related to fertility and pregnancy. HEECs grown in vitro may provide valuable information on the effects of EDCs on human endometrial functions. However, this model is not suitable as a large-scale screening tool.