Relationship between serum markers of oxidative stress and endometriosis stage in endometriosis-associated infertility women

Abstract

OBJECTIVE: To investigate the relationship between oxidative stress markers and endometriosis stage in women with endometriosis-associated infertility. DESIGN: Prospective study. MATERIALS AND METHODS: 27 infertile women with endometriosis aged ≤ 40 years and with basal follicle stimulating hormone ≤ 10 mIU/ml undergoing for intracytoplasmic sperm injection (ICSI) were evaluated. All women had laparoscopically confirmed endometriosis staged according to the revised criteria of the American Society for Reproductive Medicine. The group consisted of 8 women in stage I, 3 in stage II, 7 in stage III, and 9 in stage IV. Peripheral blood samples were collected during the early follicular phase of the cycle preceding controlled ovarian stimulation for ICSI. Serum levels of malondialdehyde (MDA), vitamin E, glutathione, and total antioxidant capacity (TAC) were determited and correlated with endometriosis stage. Data were analyzed statistically by the Pearson correlation test and by calculating sensitivity and specificity based on the ROC curve, with a difference for p <0.05 being considered significant. RESULTS: There was a statistically significant inverse correlation between serum glutathione levels and endometriosis stage (r = -0.51, p = 0.007). Glutathione levels ≤137.8 are predictors of moderate or severe endometriosis (stage 3 or 4) with 93.7% sensitivity, 54.5% specificity and 79% accuracy. There was no significant correlation between endometriosis stage and serum MDA (r = 0.057, p = 0.78), vitamin E (r = 0.09, p = 0.67) or TAC (r = 0.22, p = 0.26) levels. CONCLUSIONS: According to our findings, serum glutathione levels may be inversely correlated with endometriosis stages. It is possible that lower serum glutathione levels are related to increased consumption of this antioxidant due to a greater ROS production associated with disease severity, a possibility that should be confirmed in future studies with a greater number of patients.