INTERLEUKIN-6 SECRETION IN-VITRO IS UP-REGULATED ECTOPIC AND EUTOPIC ENDOMETRIAL STROMAL CELLS FROM WOMEN WITH ENDOMETRIOSIS

An in vitro model developed to compare human endometrial and endometri osis stromal cells was used to examine basal and stimulated expression of interleukin (IL-6). Stromal cells isolated from normal endometrium (NE) exhibited the lowest level of IL-6 secretion (84 pg/10(6) cells . 48 h), whereas those cells isolated from endometriosis implants (EI) secreted the highest concentration of this inflammatory cytokine (46, 264 pg/10(6) cells . 48 h; P < 0.01). Eutopic endometrial stromal cell s from women with endometriosis (EE) expressed an intermediate concent ration of IL-6 (831 pg/10(6) cells . 48 h). Stimulation of the various cultures with IL-1 beta dramatically augmented stromal cell productio n of IL-6. The mean concentrations of stimulated IL-6 secretion were 1 6,257, 37,800, and 264,290 pg/10(6) cells . 48 h for NE, EE, and EI ce lls, respectively (P < 0.03). Exposure of the cell cultures to 10 nmol /L estradiol had little direct effect on IL-6 production. The results indicate that endometrial stromal cells isolated from tissues of women with and without endometriosis express IL-6 under basal and cytokine- stimulated conditions. Differential responsiveness among the three cel l sources indicates that NE, EE, and EI cells have intrinsic quantitat ive differences in cytokine regulation.