Hyperinnervation in Intestinal Deep Infiltrating Endometriosis

Study Objective: To investigate the extent and types of innervation of endometriotic lesions in various regions of the bowel. Design: Retrospective nonrandomized immunohistochemical Study (Canadian Task Force classification II-3. Setting: University-based laboratory. Patients: Thirty-six women undergoing laparoscopy or laparotomy because of deep infiltrating endometriosis in various regions of the bowel, including the sigmoid colon, appendix, and rectum. Interventions: Immunohistochemical staining of endometriotic specimens with antibodies against protein gene product 9.5, neurofilament, nerve growth factor, nerve growth factor receptors tyrosine kinase receptor A and p75, growth-associated protein 43, substance P, neuropeptide Y, and vasoactive intestinal peptide to demonstrate myelinated, unmyelinated, sensory, and autonomic nerve fibers. Measurements and Main Results: There were significantly more nerve fibers in intestinal deep infiltrating endometriosis (mean [SD] 172.6 [94.2]/mm(2)) than in other deep infiltrating endometriotic lesions (e.g., Cul-de-sac and uterosacral ligament) (67.6 [65.1]/mm(2); p<.01). Intestinal deep infiltrating endometriosis was innervated abundantly by sensory A delta,sensory C, cholinergic, and adrenergic nerve fibers. Nerve growth factor, tyrosine kinase receptor A, and p75 were strongly expressed in endometriotic lesions, and growth-associated protein-43 was also strongly expressed in the endometriosis-associated nerve fibers. Conclusion: The hyperinnervation in intestinal deep infiltrating endometriosis may help to explain why patients with this type of lesion have more severe pain. Journal of Minimally Invasive Gynecology (2009) 16, 713-719 (C) 2009 AAGL. All rights reserved.