Expression of the fibrinolytic components in endometriosis

Endometriosis is a benign gynaecologic disease defined as the presence of endometrial tissue outside the uterus. This tissue has the ability to implant at ectopic sites, such as ovary and peritoneum, where a local extracellular proteolysis might take place. An altered expression of several components of the fibrinolytic system in the endometrium and peritoneal fluid of women with the disease has been suggested as a key factor in the establishment of the endometriotic lesions. There is evidence of increased fibrinolytic activity in the eutopic endometrium of these women, resulting in endometrial fragments with a high potential to degrade the extracellular matrix and facilitate implantation. Proteolytic status is determined by the imbalance between plasminogen activators and plasminogen activator inhibitors, which are expressed differently depending on the type of lesion considered and the stage of the disease. The aim of the present study is to review the expression of the plasminogen activator system in endometriosis, and to consider the clinical implications and the possible further research efforts in this disease.