Aims: To investigate the expression of the hypoxia-inducible factor-1alpha (HIF-1α) and the protein products of its target genes vascular endothelial growth factor (VEGF), erythropoietin (Epo) and angiopoietins (Angs) and the antiangiogenic pigment epithelium-derived factor (PEDF) in proliferative diabetic retinopathy (PDR) epiretinal membranes.
Methods: Sixteen membranes were studied by immunohistochemical techniques.
Results: Vascular endothelial cells expressed HIF-1alpha, Ang-2 and VEGF in 15 (93.75%), 6 (37.5%) and 9 (56.25%) membranes, respectively. There was no immunoreactivity for Epo, Ang-1 and PEDF. There were significant correlations between the number of blood vessels expressing the panendothelial marker CD34 and the numbers of blood vessels expressing HIF-1α (r=0.5542; p=0.0259), Ang-2 (r = 0.8296; p = 0.0001) and VEGF (r = 0.7425; p = 0.001). The numbers of blood vessels expressing Ang-2 and VEGF in active membranes were higher than that in inactive membranes (p=0.0149; 0.0275, respectively).
Conclusions: HIF-1α, Ang-2 and VEGF may play an important role in the pathogenesis of PDR. Our findings suggest an adverse angiogenic milieu in PDR epiretinal membranes favouring aberrant neovascularization and endothelial abnormalities.
- diabetic retinopathy
- hypoxia-inducible Factor-1α
- vascular endothelial growth factor