Peritoneal environment, cytokines and angiogenesis in the pathophysiology of endometriosis.

Endometriosis, defined by the presence of viable endometrial tissue outside the uterine cavity, is a common condition affecting 2-3% of women of reproductive age. Today, a composite theory of retrograde menstruation with implantation of endometrial fragments in conjunction with peritoneal factors to stimulate cell growth is the most widely accepted explanation. There is substantial evidence that immunological factors and angiogenesis play a decisive role in the pathogenesis of endometriosis. In women with endometriosis, there appears to be an alteration in the function of peritoneal macrophages, natural killer cells and lymphocytes. Furthermore, growth factors and inflammatory mediators in the peritoneal fluid, produced mainly by peritoneal macrophages, are altered in endometriosis, indicating a role for these immune cells and mediators in the pathogenesis of this disease.