Apoptosis of ectopic endometrial cells is impaired in women with endometriosis

Abstract

Purpose

This study was performed to assess the apoptotic index and Bcl-2 expression in ectopic endometrium of patients with endometriosis and in eutopic endometrium of patients without endometriosis, according to the phase of the menstrual cycle.

Methods

A total of eight patients with endometriosis and in eutopic endometrium of eight patients without endometriosis, according to the phase of the menstrual cycle. Samples were collected during surgical procedures and histologic sections were stained with hematoxylin-eosin and underwent morphometric analysis for assessment of the apoptotic index. TUNEL immunohistochemical assay was performed to validate the morphologic criteria used for quantification of apoptosis.

Results

The apoptotic index was significantly lower in the ectopic endometrium of patients with endometriosis in comparison to the eutopic endometrium of patients without endometriosis, regardless of the menstrual cycle phase. No statistically significant difference in endometrial Bcl-2 expression was observed among patients with and without endometriosis.

Conclusions

We conclude that ectopic endometrial tissues from women with endometriosis are less susceptible to apoptosis and these cells demonstrate an increased ability to survive and higher chances to colonize and grow in ectopic sites - important factors in the pathogenesis of endometriosis.