Peritoneal ectopic lesions from women with endometriosis show abnormalities in progesterone-dependent glycan expression.

Examination of 12 paired peritoneal ectopic and eutopic endometria for histochemical binding of Dolichos biflorus agglutinin, normally found in the mid–late secretory part of the cycle, showed a failure of lectin binding in 9 of 11 secretory-phase lesions although the eutopic specimens generally stained normally. This failure of glycan expression in the secretory phase may result from various anomalies, including an inability to respond to progesterone, possibly due to a lack of, or to nonfunctional, progesterone receptors, suggesting that an ectopic environment may produce changes in tissue cell biology and hormonal responsiveness compared with that of eutopic endometrium. Our recent study (1) on the ultrastructure of ectopic lesions from a cohort of women with endometriosis showed many abnormalities, including indications of a failure to exhibit the normal process of differentiation in the secretory half of the cycle. This was manifested by an absence of glycogen deposition in basal vacuoles and of both giant mitochondria and nucleolar channel systems in the early–midsecretory phase of the cycle. There was also considerable heterogeneity in the morphology of the glands and cystic structures observed in the electron microscope. We have now investigated whether these ultrastructural changes are accompanied by a parallel failure to show biochemical differentiation, because we have also previously shown that normal endometrial tissue undergoes a progesterone-dependent biosynthesis of glycans bound by Dolichos biflorus lectin [2] and [3]. The study group originally comprised 26 women with visually and biopsy-proven endometriosis who had undergone laparoscopic excision of endometriotic deposits and endometrial curettage, as previously described (1); however, only 12 biopsies proved to contain glandular structures in the area of tissue selected for this part of the study. Menstrual cycles (28–30 days) were regular according to the history taken at the time of the outpatient appointment, and normal ovulatory pattern was confirmed by day 21 serum progesterone. The stage of endometriosis at the time of laparoscopy was determined according to the revised American Society for Reproductive Medicine scoring system (4); all were red lesions. Eutopic tissue in each case was also taken, processed, and stained simultaneously with identical protocols.