Presence of endometrial epithelial cells in the peritoneal cavity and the mesothelial inflammatory response

Objective: To determine the contribution of endometrial cells in the development of endometriosis. Specifically the response of the mesothelium to endometrial cells in the production of monocyte chemotactic protein-1 (MCP-1), interleukin-6 (IL-6), and IL-8 was studied. Design: In vitro study. Setting: University Research Laboratory. Patients: None. Intervention(s): None. Main Outcome Measure(s): Cellular MCP-1, IL-6 secretion and MCP-1, and IL-6 and IL-8 messenger RNA expression were evaluated by ELISA and reverse transcription-polymerase chain reaction (RT-PCR) assay. Result(s): The mesothelial cells produced more MCP-1 and IL-6 than endometrial epithelial and stromal cells. Mesothelial cells cultured in the presence of endometrial epithelial cells produced even greater levels of MCP-1 and IL-6 than those cultured in the presence of stromal cells or cultured alone. The MCP-1, IL-6, and IL-8 mRNA expression also increased when mesothelial cells were co-cultured with endometrial epithelial cells. Conclusion(s): The results suggest that endometrial epithelial cells may be important in evoking the inflammatory reaction in the peritoneal cavity during retrograde menstruation and that mesothelial cells may play an important role in the chemotaxis of monocytes and in the inflammatory process during the development of endometriosis. (C) 2003 by American Society for Reproductive Medicine.