The morphological and molecular biological signs of impaired endometrial receptivity in infertility in women suffering from external genital endometriosis

Abstract

To study endometrial receptivity in infertile women with external genital endometriosis (EGE). Clinical, morphological, immunohistochemical, and molecular genetic examinations of endometrial aspiration pipelle biopsy specimens obtained on days 22-24 of the menstrual cycle from 94 infertile women with endometriosis: 50 women with Stage I-II EGE and 44 women with ovarian endometrioid cysts (OEC). A control group consisted of 54 women with tubal peritoneal factor of infertility (TPFI) and a successful attempt at IVF. Hematoxylin and eosin-stained sections were found to contain a number of endometrial surface epithelial cells containing mature pinopods. The expression levels of leukemia inhibitory factor (LIF), HOXA-10, glycodelin A, avβ3 integrin, estrogen receptors (ER) and progesterone receptors (PR), aromatase in the superficial epithelium, glandular epithelium and endometrial stroma were immunohistochemically revealed. Forty-four patients, including 17 with Stage I-II EGE and 27 with TPFI, showed mRNA expression levels of leukemia inhibitory factor receptor (LIFR), LIF, ER1, PgR, HOXA-10, and PTEN by real-time quantitative polymerase chain reaction (PCR) with a preliminary reverse transcription PCR assay. It was established that in the infertile women with Stage I-II EGE and those with OEC, endometrial receptivity was impaired, which was manifested by a decline in the number of superficial epithelial cells containing mature pinopods, as well as a decrease in the endometrial level of the key receptivity markers: αvβ3 integrin, LIF, glycodelin A, and HOXA10 and increases in the synthesis of aromatase and in the imbalance of endometrial stromal expression of ER and PR detected by immunohistochemistry (IHC). Molecular genetic study showed lower mRNA expression levels of the HOXA-10, LIFR, and PgR genes, which confirms the data obtained by IHC.