Influence of nerve growth factor in endometriosis-associated symptoms.

To investigate the role of the nerve growth factor (NGF) in the development of dysmenorrhea/pelvic pain in patients with endometriosis, we performed a prospective, clinical, blind study. Peritoneal fluids (PFs) were obtained from patients with histologically proven endometriosis. Patients with endometriosis were divided into 7 different groups depending on their preoperative pain score and symptomatology: patients with no pain, patients with minimal pain (dysmenorrhea, pelvic pain, or both), and patients with severe pain (dysmenorrhea, pelvic pain, or both) and were used for the neuronal growth assay with cultured chicken dorsal root ganglia (DRG) and for Western blot analyses. Dorsal root ganglia were stained with anti-calcitonin gene-related peptide (CGRP) and anti-growth-associated protein 43 (GAP 43). Peritoneal fluids from patients with endometriosis induce neurite outgrowth. There was no significant difference in the outgrowth between the 7 pain groups. Western blot analyses showed a moderate NGF expression in the PFs from patients with endometriosis, without significant differences in the 7 pain groups. The present study suggests that the neurotrophic properties of endometriotic tissues are endometriosis- and not pain-associated.