Fibrinolytic Activity of Subretinal Fluid after Cryopexy

Abstract

Purpose To measure the tissue plasminogen activator antigen (t-PA Ag) content and plasminogen activator inhibitor type 1 (PAI-1) activity of SRF and blood. Methods 22 patients aged from 20 to 77 years (median: 57.3 years), were studied, undergoing retinal detachment surgery. Excluded were patients with vein or arterial disease and any other factors that could change the parameters evaluated. Subretinal samples were obtained at the time of routine drainage during retinal detachment surgery, after cryopexy. Venous blood samples were taken from the cubital vein into sodium citrate solution (9: 1) immediately after induction of anesthesia but before surgery. T-PA Ag concentration and PAI-1 activity in subretinal fluid and citrated plasma and their relation to patients' age and sex, the duration and extent of retinal detachment, and degenerative changes of the retina were assessed. Results The median t-PA Ag concentration in 22 samples of SRF was 6.7 ng/ml (interquartile range 3.6 ng/ml) and PAI-1 activity 14.0 IU/ml (interquartile range 7.5 IU/ml). The median levels of t-PA Ag and PAI in plasma were respectively 10.7 ng/ml (interquartile range 8.6 ng/ml) and 15.7 IU/ml (interquartile range 12.2 IU/ml). There were no differences between the t-PA Ag concentration and PAI-1 activity in SRF and blood. We found no correlation between the levels of t-PA Ag and PAI-1 activity in SRF and age, sex, the degree of myopia, the duration and extent of retinal detachment, or retinal degenerative changes. Conclusions The parameters of the firbinolytic cascade studied here indicated the presence of high levels of t-PA Ag and PAI-1 activity in SRF.