von Willebrand factor in iris vasculature of glaucoma patients

Abstract

Background: Previous reports have indicated the role of endothelium disturbances, as expressed by von Willebrand factor (vWF) release, in pathophysiology of glaucoma. The objective of this study was to investigate the vWF expression in iris vasculature of patients with primary open-angle glaucoma (POAG).

Material and methods: Immunohistochemistry of vWF expression was performed on cryostat sections of samples collected at the time of peripheral iridectomy and controls collected from dead donors.

Results: Twenty-seven Caucasians age 66.6±3.7 with 5.8±3.7-year history of treated PAOG and 10 controls age 62.2±1.92 with no history of glaucoma. The percentage of patients who presented normal and up-regulation of vWF phenotype expression differed statistically between examined and control groups: 48% versus 100% (p=0.035, chi-square test with Yates' correction). Sex, age, glaucoma duration, and visual field quantitative indices had no impact on vWF expression. A significant correlation between mean pre-surgery intraocular pressure and vWF expression was found (Spearman r=0.42, p=0.03).

Conclusions: Considering the results, it may be suggested that vWF is actively involved in the pathophysiology of glaucoma.

Figure 1

(A) Iris cryostat section from the studied group. Intensive vWF staining on capillary vessels (arrows) (final magnification, ×200). (B) Iris cryostat section from the control group. The scattered endothelial cells are weakly stained with vWF (arrows) (final magnification, ×200).