Oxidative cell injury as a predictor of endometriosis progression

There is increasing evidence that oxidative stress is one of the key factors for progression of endometriosis. In this prospective controlled trial, we measured 6 different biomarkers of oxidative stress targeting protein, lipid, and DNA to quantify the severity and progression of endometriosis and establish a diagnostic marker for the disease.

A total of 62 consecutive patients were identified and enrolled in this study. After exclusion criteria, 44 patients were allocated to 3 groups: stage I/II (n = 14), stage III/IV (n = 16), and a control group (n = 14). The levels of 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-oxoguanine DNA glycosylase (OGG1), protein carbonyl (PC), lipid peroxidation (LPO), reactive oxygen species (ROS), and total antioxidant capacity (TAC) were accessed in peritoneal fluid and tissue.

Significantly higher levels of 8-OHdG and PC were seen in patients with endometriosis, in addition OGG1 expression was found to be significantly lower in patients with endometriosis (P < .001, P = .001, P = .033, respectively); ROS, TAC, and LPO were similar in stages I/II, stages III/IV, and control group. A predictive model was built using multivariable analyses and receiver-operating characteristics curves. The ability to predict and distinguish between patients without endometriosis, stage I/II endometriosis, and stage III/IV was very high. This model was highly discriminatory and had a concordance index of 0.87.

In this cohort, higher DNA damage and lower DNA repair activity was related to endometriosis progression. Our results indicate that oxidative stress as a biomarker of cell injury can be used as a reliable quantitative test of endometriosis severity.