Abstract
Purpose: :
To determine the vitreous levels of erythropoietin, vascular endothelial growth factor (VEGF), and soluble VEGF receptor-1 (sVEGFR-1) in patients with various vitreoretinal diseases, and to investigate the relationships among those factors.
Methods: :
Vitreous samples were obtained from 173 eyes of patients who underwent vitrectomy due to various vitreoretinal diseases (MH (n=30), BRVO (n=37), CRVO (n=27), DME (n=42), PDR (n=37)). The patients’ age ranged from 27 to 89 years old (mean=63.3±12.0 years). Erythropoietin, VEGF, and sVEGFR-1 levels were measured by enzyme-linked immunosorbent assay.
Results: :
Concentrations of both erythropoietin and VEGF in the vitreous with BRVO (154.3±165.4 mIU/ml and 270.1±501.3 pg/ml), CRVO (490.6±348.7 mIU/ml and 744.1±847.9 pg/ml), DME (461.7±398.7 mIU/ml and 566.5±798.0 pg/ml) and PDR (809.4±524.1 mIU/ml and 1129.9±1516.3 pg/ml) were significantly higher than those with MH (21.0±21.9 mIU/ml and 0 pg/ml) (P<0.01 and P<0.01, respectively). Concentrations of erythropoietin and VEGF showed a positive correlation in patients with DME (r=0.408, P<0.01), but no significant correlation was detected in the patients with BRVO (r=0.031, P=0.852), CRVO (r=0.189, P=0.344) and PDR (r=0.300, P=0.070). sVEGFR-1 levels were not significantly different among the various conditions, and the levels had no significant correlation with the levels of erythropoietin or VEGF. However, the vitreous levels of sVEGFR-1 showed a significant positive correlation with patient age (r=0.415, P<0.01). Furthermore, sVEGFR-1 levels showed a stronger correlation with age in patients with PDR (r=0.481, P<0.01) and a significant correlation with the activity of PDR (P<0.01).
Conclusions: :
Although hypoxia is one of the main inducers of both erythropoietin and VEGF expression, other factors appear to be also involved in the expression of those factors in the vitreous cavity. Vitreous levels of sVEGFR-1 could become an indicator of PDR activity, in addition to erythropoietin and VEGF.
Keywords: receptors • diabetic retinopathy • vitreous