Spontaneous apoptosis of endometrial tissue is impaired in women with endometriosis

Objective: To evaluate spontaneous apoptosis in single-cell suspensions of eutopic and ectopic endometrium from women with endometriosis and in eutopic endometrium from fertile controls without endometriosis. Design: Paired specimens of eutopic and ectopic endometrial tissue from patients with endometriosis and eutopic endometrium from controls were assessed for spontaneous apoptosis. Setting: Institute for the Study and Treatment of Endometriosis and university-based research laboratories. Patient(s): Fertile controls (n = 10) and women with untreated endometriosis (n = 16). Intervention(s): None. Main Outcome Measure(s): Spontaneous apoptosis assessed with an ELISA-based cell death detection kit. Result(s): Spontaneous apoptosis (monitored by absorbance) of eutopic endometrium from patients with endometriosis and fertile controls was 0.63 ± 0.1 and 1.43 ± 0.11, respectively. Among patients with endometriosis, spontaneous apoptosis of ectopic endometrium was 0.26 ± 0.06. Decreased apoptosis of ectopic versus eutopic endometrium was observed independent of cycle phase. Conclusion(s): The susceptibility of endometrial tissue to spontaneous apopoptosis is significantly lower in women with endometriosis than in fertile controls. We suggest that decreased susceptibility of endometrial tissue to apoptosis contributes to the etiology or pathogenesis of endometriosis.