THE VASCULAR COMPONENT OF PROLIFERATIVE VITREORETINOPATHY MEMBRANES -AN IMMUNOHISTOCHEMICAL AND ULTRASTRUCTURAL-STUDY

Background: The basic cellular components of proliferative vitreoretin opathy (PVR) membranes are well studied. Endothelial cells have also b een documented. The importance of the vascular element in PVR has rece ived little attention, as vascular components are clinically inapparen t. The aim of this study was to obtain a better characterization and q uantification of occurrence of the vascular component. Methods: Serial sections of surgically excised PVR membranes were examined with Lecti n histochemistry (25 membranes with ulex europaeus agglutinin I [UEA I ] and rhicinus communis agglutinin I [RCA II]), immunohistochemistry f or von Willebrand factor (31 membranes), and electron microscopy. Resu lts: Vascular endothelial cells were identified by visualization of UE A I and RCA I binding sites or by marking for von Willebrand factor. A total of 28.6% of the PVR membranes showed a vascular component. Vasc ular components consisted mostly of capillary-sized vessels; larger ve ssels were rarely found. Ultrastructurally, most vascular elements wer e found to be capillaries of the nonfenestrated type. Membranes from e yes that underwent PVR surgery with silicone oil tamponade showed vasc ular components less frequently (18.5%) than did membranes from eyes w ithout silicone oil (43.8%).