Plasminogen Activator Inhibitor Type 2 in Human Tears and Blood during Pregnancy

Purpose: During pregnancy, systemic blood levels of plasminogen activator inhibitors (PAIs), estradiol (E2) and progesterone (P4) are expected to rise with gestational age. This work examines whether a corresponding rise in PAIs occurs in tears. Methods: Tear and blood samples were collected opportunistically from women during pregnancy: PAI-2 and PAI-1 levels were measured using enzyme-linked immunosorbent assay (ELISA) tests. Blood levels of E2 and P4 were measured using chemiluminescence immunoassays. Results: Levels of PAI-2 from tears of pregnant women did not increase and did not correlate with gestation. Levels of PAI-2, E2 and P4 in blood significantly increased over gestation. Tear PAI-2 levels did not correlate with blood levels of PAI-2, E2 or P4. Although blood levels of PAI-1 increased with gestation, tear levels of PAI-1 were below the ELISA detection limit, similar to the situation for non-pregnant subjects. Conclusions: Tear PAI-2 levels are dissociated from the progression of pregnancy and the concomitant elevated systemic blood PAI-2, E2 and P4 levels, indicating the possibility of local control of proteolysis in the eye during pregnancy in the absence of wounding or surgery on the eye.