Neurotrophins and Cytokines in Endometriosis Pain

Endometriosis is a common gynecological syndrome associated with pain and infertility and characterized by the growth of hormone-responsive endometrial tissue outside the uterine cavity. Three major subtypes of ectopic endometriotic implants are currently recognized, based on their anatomic location: (1) attached to the peritoneal surface, (2) encapsulated within the ovary, or (3) infiltrating the connective tissues of the rectovaginal septum. However, more widely dispersed lesions have been described in the pleura, the cutaneous skin, and even the lacrimal duct [1]. The high prevalence of endometriosis is broadly recognized, and recent population-based estimates put its overall frequency among reproductive-age women at around 11% [2]. This disease is accompanied by pelvic pain in millions of women worldwide, resulting in work absenteeism, social isolation, and high costs of medical and surgical therapies. In the United States, endometriosis is the third commonest indication for hysterectomy, a procedure that can be particularly devastating in women under age 30, because they are likely to experience residual somatic symptoms and a severe psychological sense of loss.