Mitogen(s) for endometrial-like cells can be detected in human peritoneal fluid

OBJECTIVE: To characterize the presence of mitogen(s) in the peritoneal fluid (PF). DESIGN: Aliquots of PF aspirated at laparoscopy were assessed for mitogenic activity by the rate of [3H]-thymidine incorporation into the deoxyribonucleic acid of various cell lines. SETTING: Peritoneal fluids were obtained from patients having a laparoscopy for the investigation of infertility or pelvic pain or for tubal ligation. PATIENTS: Seven women with laparoscopic evidence of endometriosis (stage I and II) and six without evidence of endometriosis. INTERVENTION: None. MAIN OUTCOME MEASURE: After 24 hours of culture in absence of serum, NIH/3T3 mouse embryo fibroblasts, (KLE) human endometrial adenocarcinoma cells, and primary cultures of rabbit endometrial cells were incubated in the presence of appropriate amounts of PF or bovine serum albumin (control) for 22 hours before adding the [3H]-thymidine for 2 hours. RESULTS: Aliquots of PF containing greater than 100 micrograms/mL total protein concentration stimulated the proliferation of all cell types. This mitogenic effect was dose-dependent and was greatest on endometrial-like cells. The mitogenic activity was fully recovered after adsorption on dextran-coated charcoal and was sensitive to tryptic digestion and to heat. It could not be retained on cartridge of C18 silica and was calculated to have a molecular weight greater than 30,000 by gel permeation chromatography. CONCLUSIONS: Peritoneal fluid from women with or without endometriosis contain growth factor(s) that are proteinaceous in nature and capable of stimulating the proliferation of endometrial-like cells and fibroblasts. These mitogens could play a role in the pathogenesis of endometriosis.