Endometrial expression of telomerase, progesterone, and estrogen receptors during the implantation window in patients with recurrent implantation failure

Abstract

Telomerase plays a critical role in cell proliferation and senescence, but the exact involvement of endometrial telomerase in recurrent implantation failure (RIF) is unknown. We collected endometrial biopsies from RIF patients (N = 30) and fertile women (N = 30). Real-time PCR was performed for detecting changes in telomerase reverse transcriptase (Tert), ER alpha, and PR expression at the transcript level, and the correlation between the variable expressions of these genes was tested using regression analysis. Then, western blot and immunohistochemistry were used to analyze the expression profiles of TERT and ER alpha at the protein level. Compared to the control, Tert expression was substantially increased, whereas ER alpha expression significantly decreased in the endometrium with RIF. No change was observed in PR expression. Tert expression was inversely associated with ER alpha expression. TERT protein expression in RIF patients was also clearly elevated, and was localized to both the endometrial epithelium and stromal cells. However, the signals for ER alpha in the stromal cells were weaker than those in the control. Expression of endometrial telomerase was substantially enhanced as ER alpha decreased in RIF patients during the implantation window.