High subretinal fluid procoagulant activity in rhegmatogenous retinal detachment

An increased mRNA expression of genes related to blood coagulation has been demonstrated in an experimental retinal detachment model but has not yet been confirmed in human clinical specimens. Tissue factor (TF), the initiating factor of blood coagulation, may be a determinant of the extent of tissue injury after rhegmatogenous retinal detachment (RRD). This study was conducted to determine whether subretinal fluid and vitreous fluid collected from patients with RRD have a procoagulant effect. Calibrated thrombin generation (CAT) was used to investigate the thrombogenic properties of 28 subretinal fluids collected during scleral buckling surgery for RRD. Further, the thrombogenic properties of vitreous fluids from RRD (n = 12), macular pucker (n = 5), macular hole (n = 6), and proliferative diabetic retinopathy (n = 5) were compared with the properties of eye bank eyes (n = 11), which served as control specimens. The procoagulant activity of TF was determined with Western blot analysis. The addition of subretinal fluid from all RRD patients (28/28, 100%) induced thrombin generation in normal and severely factor (F)XII-deficient plasma. Contrary to the subretinal fluid, the addition of vitreous fluids from various ocular disorders evoked very little thrombin generation in normal and severely FXII-deficient plasma (4/12, 33% RRD; 1/5, 20% macular pucker; 0/6, 0% macular hole; 0/5, 0% proliferative diabetic retinopathy; and 2/11, 18% eye bank eyes). The procoagulant activity in subretinal fluid was almost completely neutralized by antibodies against human TF. The presence of TF in subretinal fluid was confirmed by Western blot. Subretinal fluid of patients with RRD induces high procoagulant activity, determined by measuring the level of tissue factor.