Inverse correlation between peritoneal ¯uid leptin concentrations and the extent of endometriosis

BACKGROUND: The role of leptin in reproductive processes has received increasing attention. Because leptin has intrinsic angiogenic properties, may be induced by in¯ammatory cytokines and induces matrix metalloproteinases, we examined peritoneal ¯uid (PF) leptin concentrations in women with endometriosis. METHODS: PF samples were collected from 60 women undergoing laparoscopy for endometriosis, and 18 controls undergoing tubal sterilization. Fifty of the women with endometriosis had received no prior hormonal treatment, while 10 with moderate± severe endometriosis were using GnRH agonists. RESULTS: Women with untreated endometriosis had signi®cantly higher (mean 6 SD) PF leptin levels (34.9 6 7.9 ng/ml) than controls (17.9 6 4.1 ng/ml; P < 0.001). However, PF leptin levels were inversely correlated with the stage of disease (r = ±0.62; P < 0.001). Nevertheless, women with stage III±IV endometriosis maintained signi®cantly higher PF leptin levels (26.3 6 4.8 ng/ml; P < 0.001) than controls. Although PF leptin levels were signi®cantly higher in the secretory versus proliferative phase of the menstrual cycle, they remained higher in both phases in women with untreated endometriosis. PF leptin levels in women on GnRH agonists were similar to controls. CONCLUSIONS: PF leptin levels are elevated in women with endometriosis, but inversely correlated with extent of disease. These ®ndings suggest a potential role for leptin in the pathogenesis of peritoneal endometriosis. Key words: angiogenesis/cytokines/endometriosis/leptin/peritoneal ¯uid