Assessing brain-derived neurotrophic factor as a novel clinical marker of endometriosis.

Objective: To evaluate novel clinical markers of endometriosis including the neurotrophins brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), and neurotrophin 4/5 (NT4/5) and compare them to others previously reported in the literature including cancer antigen 125 (CA-125) and C-reactive protein (CRP).

Design: Prospective study.

Setting: University hospital.

Patient(s): One hundred thirty-eight women were prospectively and consecutively recruited (April 2011-April 2015; cases: undergoing endometriosis surgery, n = 96; controls: benign gynecological surgery, n = 24 combined with healthy women, no history of pelvic pain, not undergoing surgery, n = 18).

Intervention(s): Collection of peripheral blood, gynecological and demographic information, eutopic biopsy in women undergoing laparoscopy.

Main Outcome Measure(s): Circulating BDNF, NGF, NT4/5, CA-125, and CRP were quantified by ELISA.

Result(s): Plasma concentrations of BDNF were significantly greater in women with endometriosis (1,091.9 pg/mL [640.4-1,683.1]; n = 68, untreated) than in controls (731.4 pg/mL [352.1-1,176.2]; n = 36), whereas circulating NGF, NT4/5, CA-125, and CRP were not different. When assessed for their ability to differentiate between women with revised Classification of the American Society of Reproductive Medicine stage 1 and 2 or stage 3 and 4 disease and controls, BDNF was the only putative marker able to identify stage 1 and 2 disease, with a sensitivity and specificity of 91.7% and 69.4%, respectively, using an arbitrary cutoff value of 1,000 pg/mL. We also demonstrated that circulating BDNF in women with endometriosis who were receiving ovarian suppression for disease was equivalent to that in the control group. This suggests that BDNF may also offer the opportunity to monitor patient response to treatment.

Conclusion(s): Plasma BDNF is a potentially useful clinical marker of endometriosis that is superior to NGF, NT4/5, CA-125, and CRP.