Role of endocrine status and cell type in adhesion of human endometrial cells to the peritoneum in nude mice.

OBJECTIVE: To investigate the role of different cellular types (epithelial and stromal endometrial cells and peritoneal cells) in the ectopic implantation of endometrium and to evaluate the importance of endocrine environment on the adhesion of endometrial cells to the peritoneum.

DESIGN: Experimental prospective study.

SETTING: University hospital, department of cell biology.

ANIMAL(S): One hundred one nude mice.

INTERVENTION(S): Monolayer culture of human epithelial and stromal endometrial cells obtained from patients undergoing hysterectomy or laparoscopy for benign disease. Intraperitoneal injection of cells into nude mice.

MAIN OUTCOME MEASURE(S): Two weeks after cell injection, adhesion of endometrial cells was evaluated by histological and immunohistochemical examination.

RESULT(S): Mixed cultures of stromal and epithelial cells, but not purified epithelial or stromal cells alone, adhered to the mouse peritoneum and led to endometriotic-like nodules. Pretreatment of cells with estrogen alone or with estrogen and progestin resulted in a higher percentage of animals developing endometriotic-like nodules, whereas treatment with progestin alone did not affect endometriotic implantation.

CONCLUSION(S): Our data indicate that the success of endometrial cell implantation is dependent on the cooperativeness between stromal and epithelial endometrial cells, as well as on the endocrine environment of endometrial cells, but not that of recipient animals. The results emphasize the role of both endometrial cell types for ectopic implantation.