Progesterone's role in deep infiltrating endometriosis: Progesterone receptor and estrogen metabolism enzymes expression and physiological changes in primary endometrial stromal cell culture

To study progesterone signaling activation, we measured changes in extracellular pH as a reflection of Na+/H+ exchange (NHE) using a cytosensor microphysiometer and assessed progesterone receptor (PR) and estrogen metabolism enzymes mRNA expression in cultured endometrial cells from women with deep infiltrating endometriosis and healthy controls using real-time quantitative PCR. This study was conducted at a University hospital and included patients with and without deep infiltrating endometriosis (DIE). Primary endometrial stromal cells (ECs) from women with DIE and controls were treated with 17β-estradiol and progesterone prior to microphysiometer measurements and qPCR evaluations. Decreased progesterone responsiveness and decreased total nuclear PR and HSD17B1 mRNA expression were observed in cultured ECs from women with deep infiltrating endometriosis relative to those from control samples before and after hormone treatment. These cells also showed increased 17β-hydroxysteroid dehydrogenases types 2 (HSD17B2) relative to control group and increased expression of aromatase (CYP19) after exposure to progesterone. These physiological and expression patterns observed in ECs cultures from women with DIE reinforces previous findings in the literature supporting the progesterone resistance hypothesis in the pathogenesis of endometriosis.