Expression of Endometrial Receptivity Markers throughout the Menstrual Cycle in Women with and without Uterine Adenomyosis.

Background/Objectives : While it is known that adenomyosis is associated with poor reproductive outcomes, the underlying mechanisms are unclear, and to date, there is no standard treatment protocol for these patients. Endometrium from adenomyosis patients is characterized by several abnormalities, potentially resulting in impaired receptivity and subsequent implantation failure. Methods : Endometrial biopsies were collected from 26 women with adenomyosis and 26 control subjects. Immunohistochemistry was performed to evaluate the expression of markers of endometrial receptivity, namely the progesterone receptor (PR), glycodelin, leukemia inhibitory factor (LIF), homeobox A10 (HOXA10), integrin beta chain beta 3 (integrin β3) and osteopontin. Scanning electron microscopy was used to observe pinopodes on the surface of mid-secretory endometrial epithelium. Results : PR, LIF and osteopontin expression were all found to be weaker in secretory-phase stroma from adenomyosis patients than in healthy controls. HOXA10 expression was decreased in adenomyosis during the secretory phase, and also the proliferative phase, where it reached statistical significance in both epithelial and stromal compartments. Glycodelin and integrin β3 levels did not differ between diseased and healthy tissues in any of the cycle phases. Pinopodes were fewer and at later developmental stages in adenomyosis compared to those on the surface of healthy endometrium from the same time period of the menstrual cycle. Conclusions : Endometrium from adenomyosis patients is characterized by abnormal expression of various receptivity markers. The stromal compartment appears to be affected most, showing reduced expression of PR, LIF and osteopontin in the secretory phase and lower levels of HOXA10 during both proliferative and secretory phases. Decreased receptivity due to impaired stromal decidualization may contribute to poor reproductive outcomes in adenomyosis patients.