Induction of the epithelial-mesenchymal transition in the endometrium by chronic endometritis in infertile patients

Abstract

Background The purpose of the present study was to evaluate the relationship between chronic endometritis (CE) and the epithelial-mesenchymal transition (EMT) in the eutopic endometrium of infertile patients in the implantation phase. Methods Endometrial biopsy specimens from 74 infertility patients were enrolled. The presence of CE was investigated by immunostaining for CD138. Immunohistochemical staining for E-cadherin, N-cadherin, Slug, and Snail was performed, and expression profiles were statistically analyzed according to the presence of CE. When loss of E-cadherin expression and/or positive N-cadherin expression was detected, the specimen was considered EMT-positive. EMT-positive cases were also statistically analyzed according to the presence of CE. Patients’ characteristics were compared between the EMT-positive and EMT-negative groups. Logistic regression analysis was also performed with variables including age, body mass index (BMI), gravidity, parity, and each factor causing infertility to examine the independent effect of each variable on EMT-positive status. Results Loss of E-cadherin expression, N-cadherin expression and EMT-positive were significant in CE patients (p = 0.0037, 0.0039 and < 0.0001, respectively). Slug, cytoplasmic Snail, and nuclear Snail expression were significant in CE patients (p = 0.0008, 0.0004 and 0.028, respectively). Differences were detected in unexplained infertility and CE between EMT-positive and EMT-negative cases. Unexplained infertility and CE were identified as variables related to EMT-positive status on logistic analysis. Conclusion The EMT was frequent in the eutopic endometrium in infertile patients with CE. Since the EMT is associated with unexplained infertility and CE, the EMT appears to be involved in altered mechanisms of implantation.

Correlation between hysteroscopy findings in patients with hydrosalpinx and chronic endometritis

“…8 Chronic endometritis is frequently asymptomatic, and hysteroscopy and immunohistochemistry staining for CD138 of the endometrial biopsy specimens were the main methods in the diagnosis of CE. 12,15 Endometrial hyperemia and micro-polyps might be suggestive of CE. 16 However, CE cannot be ruled out with the absence of hysteroscopic visualization features.…”