Induction of monocyte chemotactic protein-1 in peritoneal mesothelial and endometrial cells by oxidized low-density lipoprotein and peritoneal fluid from women with endometriosis

Objective: To elucidate the effect of oxidized low-density lipoprotein (LDL) and peritoneal fluid of women with endometriosis on monocyte chemotactic protein-1 (MCP-1) production by peritoneal mesothelial cells and endometrial cells. Design: In vitro study. Setting: University medical center. Patient(s): Five women undergoing surgery for pelvic pain, infertility, or endometriosis; five women without endometriosis who were undergoing tubal ligation were the controls. Intervention(s): Mesothelial cells and endometrial cells in culture were treated with oxidized LDL and peritoneal fluid from control and endometriosis patients, then MCP-1 levels were measured. Main Outcome Measure(s): ELISA was used to measure MCP-1 in the culture supernatants exposed to oxidized LDL and peritoneal fluid from control and endometriosis patients. Cellular MCP-1 messenger RNA expression was evaluated by reverse transcription-polymerase chain reaction (RT-PCR) assay. Result(s): Treatment with oxidized LDL caused an increase in accumulation of immunoreactive MCP-1 in the medium of cultured mesothelial and endometrial cells (primary endometrial stromal cells and endometrial cell line EM42). The mesothelial cells secreted more MCP-1 than did endometrial cells under the culture condition. The EM42 cells cultured in the presence of peritoneal fluid from endometriosis patients secreted more MCP-1 than those cultured with peritoneal fluid from normal women. However, no differences were found in MCP-1 levels in the supernatant of endometrial stromal cells cultured with peritoneal fluid. Conclusion(s): This is the first report of MCP-1 expression in mesothelial cells induced by oxidized LDL, and provides direct evidence of inflammatory action of peritoneal fluid of women with endometriosis.