Objective: To evaluate endometrial receptivity in women with chronic endometritis (CE), by studying the nature of secretory transformations, the number of mature pinopodia in the surface epithelium, the expression of steroid hormone receptors and leukemia inhibitory factor (LIF).
Subjects and methods: Endometrium morphology was analyzed in 76 patients with CE (a study group) and 20 gynecologically healthy women (a control group) who sought family planning advice and examined using the uniform scheme. Morphological examination of the endometrium obtained by Pipelle biopsy on days 7-8 after ovulation involved histological and immunohistochemical studies: the number of mature pinopidia and the expression of estrogen and progesterone receptors (ER and PR) were determined, by estimating the PR/ER ratio and the marker of LIF receptivity in the endometrial epithelium and stroma.
Results and discussion: In the women with CE, the level of surface epitheliocytes with pinopodia was significantly lower than that in the comparison group (mean 37.5 +/- 2.1; p < 0.01). There was an increase in ER expression in the integumentary and glandular epithelium (mean 102.5 +/- 6.8 scores; p < 0.01) and stromal cells (110.2 +/- 8.3 scores; p > 0.05). In the control group, the intensity of PR expression was, on the contrary, significantly lower in both the integumentary epithelium and glandulocytes (mean 104.7 +/- 5.5 scores; p < 0.01) and stromal cells (178.5 +/- 11.3 scores; p < 0.01). In the study group, the PR/ER ratio was less than 2 in all cases: the mean PR/ER ratio was 1.1 +/- 0.09 for surface epitheliocytes and glandulocytes and 1.6 +/- 0.1 for stromal cells. In CE, the intensity of LIF expression was dramatically reduced and equal to 0.95 +/- 1.3 scores (p < 0.01). The found regularities suggest that CE is accompanied by an almost 4-fold decrease in LIF expression, which is evidence for significantly suppressed endometrial receptivity and may be regarded as a prognostic marker of failed implantation.
Conclusion: The patients with CE were found to have an endometrial receptivity disorder involving the damaged surface epithelium of the uterine mucosa, pinopodia immaturity by the implantation window, decreased LIF expression, and ER hyperexpression. This may give rise to reproductive dysfunction in women with CE.