Plasminogen activator inhibitor-1 in endometriosis

Endometriosis is a disease that affects almost 10% of reproductive-age women, where 50 % of these women have pelvic pain with sexual intercourse. Deep endometriosis is defined as an endometriotic lesion penetrating to a depth of 5 mm or more, and is characterized by both fibrosis (forming nodules) and invasion (into structures such as the colon). Other groups have found that increased plasminogen activator inhibitor-1 (PAI-1) or (SERPINE1) expression was associated with fibrosis and tumor invasion. In addition, a previous study found that the SERPINE1 4G allele (and thus increased gene expression) was associated with increased pain in women with endometriosis, and other work suggested that SERPINE1 may be implicated in local neurogenesis. The objective of this thesis is to determine whether PAI-1 expression is associated with a) deep infiltrating endometriosis; and b) deep dyspareunia. We propose that increased PAI-1 expression will be associated with deep infiltrating endometriosis, and increased pain in endometriosis via an increase in local nerve fibers. We utilized immunohistochemical analysis using a validated PAI-1 antibody. In the first cohort, we examined PAI-1 expression in deep infiltrating endometriosis and compared to endometrioma, superficial endometriosis, and eutopic endometrium. In the second cohort, we examined PAI-1 expression in cul-de-sac endometriosis from women with or without deep dyspareunia. We found higher expression of PAI-1 in deep infiltrating endometriosis (n = 10) compared to superficial endometriosis (n = 10) (p = 0.031) and eutopic endometrium (n = 10) (p = 0.002). In the second cohort, we found lower expression of PAI-1 in women with more severe deep dyspareunia (r = - 0.352, n =35, p = 0.038). However, there was no association between PAI-1 expression and local nerve bundle density. In conclusion, we observed higher PAI-1 expression in deep infiltrating endometriosis, but lower PAI-1 expression in endometriosis from women with deep dyspareunia. Further research is needed to clarify the complexities of PAI-1 expression in endometriosis.