This study was designed to measure
leptin concentrations in the peritoneal fluid (PF) of women with different aspects of pelvic
endometriosis. Among 36 consecutive women undergoing laparoscopy, nine were diagnosed as having minimal-mild
endometriosis (stage I-II). Among nine other subjects with advanced stage (III-IV) disease, six showed one or more ovarian endometriotic
cysts as the only operative finding. The remaining 18 unaffected women constituted the control group. Patients with
endometriosis had significantly higher PF
leptin concentrations (32.6 +/- 16.2 versus 17.1 +/- 6.6 ng/ml, P = 0.002); this difference remained significant when corrected for body mass index (BMI) (PF
leptin/BMI ratio 1.41 +/- 0.67 versus 0.76 +/- 0.28, P = 0.001). Furthermore, the PF
leptin/BMI ratio was significantly higher in women with peritoneal implants than in those in whom no implant was found at laparoscopy (1.6 +/- 0.7 versus 0.83 +/- 0.33, P = 0.007). Conversely, patients with one or more ovarian endometriomata as the only finding, had a PF
leptin/BMI ratio comparable with that in women where no
cyst was found (1.05 +/- 0.4 versus 1.1 +/- 0.65). In women with stage I-II
endometriosis, a higher mean PF
leptin/BMI ratio was found compared with those affected by stage III-IV (1.78 +/- 0.68 versus 1.05 +/- 0.43, P = 0.01). These results show that during
endometriosis the presence of
peritoneal disease, and not of ovarian endometriotic
cysts, influences
leptin concentrations in PF. The data suggest that
leptin may play a role in the development of peritoneal
endometriosis, and that different biochemical phenomena might be involved in the pathogenesis of the ovarian form of the disease.