Daily variation of plasma Brain-derived Neurotrophic factor in women with endometriosis

Purpose: Endometriosis is a benign gynecological disease affecting women in their reproductive age and characterized by chronic pelvic pain and infertility. Previous studies have demonstrated the role of neurotrophins (in particular brain-derived neurotrophic factor) in the pain pathway and in inflammation processes, which both characterize endometriosis. Our previous study revealed higher brain-derived neurotrophic factor levels in patients suffering from endometriosis than in healthy women during the follicular phase of the menstrual cycle, thus suggesting a neuroprotective role of this particular neurotrophin in response to a neuro-inflammatory reaction. The aim of this study is to assess whether the diurnal variation of brain-derived neurotrophic factor and the circadian rhythm of cortisol are preserved in this kind of patient. Methods: We enrolled 11 healthy women (age range 20 to 30, BMI range 20.6 to 29.3), and 11 women suffering from endometriosis (age range 25 to 35, BMI range 20.5 to 27.2). Blood samples were withdrawn from each subject in the follicular phase at 8:00, 12:00, 16:00, 20:00, 24:00, and at 8:00 the following day, in order to assess BDNF and cortisol plasma levels during the day. Results: We found a preserved cortisol circadian rhythm in patients with endometriosis, while the BDNF daily variation is blunted if compared to healthy women in follicular phase. Conclusions: In endometriosis the biological rhythm is preserved, which is demonstrated by the cortisol's rhythm, and the lack of BDNF variation is probably only blunted by the increase in its peripheral production, because of the physiopathologic mechanisms of this disease