The role of the peritoneum and transforming growth factor β in the aetiology of endometriosis

Endometriosis is a benign inflammatory disorder, defined by the presence of endometrial tissue outside the uterus with lesions typically found on the pelvic peritoneum in close association with the peritoneal mesothelium. The prevalence of endometriosis is estimated at 6-10% of women of reproductive age and it is associated with chronic pelvic pain, dysmenorrhoea, dyspareunia and infertility. Surgical excision can provide symptom relief, but symptoms recur in up to 75% of surgical cases and available medical treatments have undesirable side effects. New treatments are limited due to our poor understanding of the aetiology of endometriosis. To date, the majority of research has focused on changes within the ectopic endometrial tissue to explain the development of endometriosis lesions, however, there is increasing evidence that the peritoneal mesothelium plays an important role. According to Sampson’s theory of retrograde menstruation, ectopic endometrial cells must first have to attach to the surface of the peritoneum before undergoing invasion, proliferation, and neoangiogenesis. TGF-β1 is an inflammatory growth factor that regulates a variety of cellular functions including; cell adhesion, cell invasion ... (continues)