CO2 promotes plasminogen activator inhibitor type 1 expression in human mesothelial cells

Background: Previous observations have indicated that CO2 insufflation increases peritoneal plasminogen activator inhibitor type 1 (PAI-1) expression. Methods: Primarily cultured human peritoneal mesothelial cells were exposed to either flowing or pressurized CO2 for 90 min. Unexposed cultures served as controls. Samples of cell culture media were taken at 0, 5, and 24 h after exposure to measure media pH, PAI-1, and tissue-type plasminogen activator (t-PA) protein release. Simultaneous samples were taken to measure PAI-1 and t-PA mRNA expression. Results: Mesothelial cells exposed to flowing CO2 released more PAI-1 than those exposed to pressurized CO2 (p < 0.001) and controls (p < 0.001). Cells exposed to flowing CO2 had an increased PAI-1 mRNA expression at 5 h. Conclusions: CO2 increased mesothelial cell PAI-1 expression involving a transcriptional mechanism. These findings might provide a mechanism for adhesion formation and cancer progression following laparoscopic surgery.