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The vascular component of proliferative vitreoretinopathy membranes: an immunohistochemical and ultrastructural study.

BACKGROUND
The basic cellular components of proliferative vitreoretinopathy (PVR) membranes are well studied. Endothelial cells have also been documented. The importance of the vascular element in PVR has received little attention, as vascular components are clinically inapparent. The aim of this study was to obtain a better characterization and quantification of occurrence of the vascular component.


METHODS
Serial sections of surgically excised PVR membranes were examined with Lectin histochemistry (25 membranes with ulex europaeus agglutinin I [UEA I] and rhicinus communis agglutinin I [RCA I]), immunohistochemistry for von Willebrand factor (31 membranes), and electron microscopy.


RESULTS
Vascular endothelial cells were identified by visualization of UEA 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. Vascular components consisted mostly of capillary-sized vessels; larger vessels were rarely found. Ultrastructurally, most vascular elements were found to be capillaries of the nonfenestrated type. Membranes from eyes that underwent PVR surgery with silicone oil tamponade showed vascular components less frequently (18.5%) than did membranes from eyes without silicone oil (43.8%).