Expression of pigment epithelium-derived factor and vascular endothelial growth factor in fibrovascular membranes from patients with proliferative diabetic retinopathy

Purpose: The expression of pigment epithelium-derived factor (PEDF), a strong inhibitor of angiogenesis, has not been examined in human ocular fibrovascular membranes, to the best of our knowledge. The purpose of this study was to determine whether PEDF is expressed in the fibrovascular membranes in eves of patients with proliferative diabetic retinopathy (PDR), and to compare the expression of PEDF with that of vascular endothelial growth factor (VEGF). Methods: The expression of PEDF and VEGF in the fibrovascular membranes excised during vitreous surgery in eight cases of PDR was determined by immunohistochemistry. Results: VEGF was strongly expressed in the endothelial cells of newly formed vessels in the fibrovascular membranes. In contrast, PEDF was weakly expressed in the endothelial cells and was prominently expressed in the extracellular matrix and fibrous tissue surrounding the new vessels. Conclusions: Our results suggest that PEDF along with VEGF. may modulate the formation of fibrovascular membranes in patients with PDR.