Selective localization of interleukin-1 receptor antagonist in eutopic endometrium and endometriotic implants.

OBJECTIVES: To determine whether interleukin-1 receptor antagonist (IL-1ra) expression was concordant in eutopic endometrium and endometriotic implants. DESIGN: Paired samples of endometrium and endometriotic implants from eight patients with endometriosis were used. MAIN OUTCOME MEASURES: Interleukin-1 receptor antagonist was demonstrated immunohistochemically on frozen sections of eutopic and ectopic endometria. A sandwich technique with polyclonal rabbit anti-IL-1ra antibody and an avidin-biotin reagent (Vector Laboratories, Inc. Burlingame, CA) was used. RESULTS: Seven of eight (88%) eutopic endometrial sections revealed staining of glandular epithelium with complete absence of any staining of the stromal compartment. In the counterpart sections of endometriosis, the glandular as well as the stromal compartments were negative for IL-1ra in all patients. CONCLUSION: These data suggest a differential production of the IL-1ra in eutopic endometrium and endometriotic implants. The potential clinical implications of this finding are discussed.

The effect of growth factors on the proliferation of human endometrial stromal cells in culture.

OBJECTIVE: Development of ectopic implants of endometriosis is associated with both an inflammatory response by macrophages and endometrial stromal cell proliferation. Macrophages are capable of releasing a variety of inflammatory mediators, including growth factors. To assess the impact of such factors on endometrial tissue, we have studied the effects of recombinant growth factors, fibroblast growth factor, epidermal growth factor, transforming growth factor-alpha, and inflammation mediators transforming growth factor-beta, and tumor necrosis factor-alpha on human endometrial stromal cell proliferation. STUDY DESIGN: Increasing concentrations of these compounds were added to cultures of primary, secondary, and long-term stromal cells and the cells were harvested at 24, 48, and 72 hours. RESULTS: Epidermal growth factor, transforming growth factor-alpha, transforming growth factor-beta, and fibroblast growth factor induced a statistically significant, dose-dependent increase in stromal cell thymidine uptake of 1.5- to fivefold. The cytokine tumor necrosis factor had no effect alone, but the combination of fibroblast growth factor and tumor necrosis factor had a synergistic effect, increasing cell proliferation 25% to 84% over fibroblast growth factor alone. CONCLUSION: The stromal cell response to a wide range of cell growth effectors and the potential of mediators like tumor necrosis factor-alpha to synergize suggest that such macrophage-secretory products may contribute to proliferation of endometrial implants in vivo.

Interleukin-1 inhibits growth of normal human endometrial stromal cells.

OBJECTIVE: To understand growth regulation of the endometrium by studying the effect of interleukin-1 beta (IL-1) on human endometrial stromal cell proliferation in vitro. METHODS: Endometrial stromal cells from human endometrium were separated and purified and placed in culture. Fresh and first- and sixth-passage cells were incubated with IL-1 (0.025, 0.25, and 2.5 ng/mL) for 24, 48, and 72 hours, respectively. Proliferation as a function of DNA synthesis was assessed by measuring 3H-thymidine incorporation. Experiments were then repeated in the presence of indomethacin to determine whether IL-1 effects were dependent upon prostaglandin synthesis. We evaluated overall growth by adding IL-1 to cell cultures of sixth-passage stromal cells every 3 days and by performing cell count studies. RESULTS: Interleukin-1 beta significantly inhibited 3H-thymidine uptake in freshly explanted endometrial stromal cells at all doses in a dose-dependent manner; a 44% inhibition was seen at 2.5 ng/mL IL-1 after 72 hours of incubation. In first- and sixth-passage cells, 3H-thymidine uptake was inhibited only at intermediate and high doses of IL-1. Cell count studies showed that sixth-passage cells were significantly inhibited by IL-1 after 23 days of growth (22%; P less than .01). Adding indomethacin did not affect inhibition of growth. CONCLUSION: Interleukin-1 beta inhibits growth of normal human endometrial stromal cells in vitro and does not appear to be mediated by arachidonic acid metabolites. This inhibition of growth may be important for maintenance of a normal endometrial phenotype.

Immunohistochemical detection of type I, III, and IV collagen in endometriosis implants.

OBJECTIVE: To determine if types I, III, or IV collagen are present in ectopic endometrium and to determine which type(s) of collagen are present in the connective tissue surrounding ectopic endometrial implants. DESIGN: Paired intrauterine and ectopic endometrial samples were obtained for study at the time of laparoscopy from women in the proliferative and secretory phase of the menstrual cycle. Connective tissue surrounding each ectopic implant was also obtained for study. SETTING: Academic research environment with institutional review board approval. PATIENTS: Six patients without endometriosis were used as controls. Ten additional patients with stage II or III endometriosis were studied. Only women on no medications participated in the study. MAIN OUTCOME MEASURES: Immunohistochemical techniques were used to identify the presence of collagen in biopsied specimens. RESULTS: Each collagen type studied was identified in the intrauterine endometrium of patients with and without endometriosis. All collagen types were also identified in each of the ectopic endometrial implants studied. The distribution of collagen in ectopic endometrial implants was similar to the distribution of collagen seen in intrauterine endometrium obtained from patients with or without endometriosis. Collagenous tissue that contained type I collagen was identified at the periphery of deep ectopic implants. CONCLUSIONS: This study demonstrates the presence of type I, III, and IV collagen in the intrauterine and ectopic endometrium of patients with endometriosis. Type I collagen was the predominant collagen present in the surrounding collagenous tissue associated with deep, ectopic endometrial implants.