Background: We have recently found that pigment epithelium-derived factor (PEDF), a glycoprotein with potent neuronal differentiating activity, inhibits advanced glycation end product-induced retinal hyperpermeability and angiogenesis through its anti- oxidative properties, suggesting that PEDF may exert beneficial effects on diabetic retinopathy by acting as an endogenous anti-oxidant. However, the interrelationship between PEDF and total anti-oxidant capacity in the eye remains to be elucidated. In this study, we determined vitreous PEDF and total anti- oxidant levels in patients with proliferative diabetic retinopathy (PDR), and investigated the relationship between them.
Methods: Vitreous levels of PEDF and total anti- oxidant capacity were measured by an ELISA in 39 eyes of 36 diabetic patients with PDR and in 29 eyes of 29 non- diabetic control subjects.
Results: Vitreous levels of total anti-oxidant capacity were significantly lower in diabetic patients with PDR than in control subjects (0.16±0.05 mmol/l vs 0.24±0.09 mmol/l, p<0.001). PEDF levels were positively correlated with total anti-oxidant status in the vitreous of patients with PDR (r=0.37, p<0.05) and control subjects (r=0.41, p<0.05). Further, vitreous levels of PEDF in PDR patients without vitreous hemorrhages (VH(-)) were significantly (p<0.05) decreased, compared with those in the control or PDR patients with vitreous hemorrhage (VH(+)) (PDR VH(-), 4.5±1.1 μg/ml; control, 7.4±4.1 μg/ml; PDR VH(+) 8.5±3.6 μg/ml)
Conclusion: This study demonstrates that PEDF levels are associated with total anti-oxidant capacity of vitreous in humans. Our observations suggest that PEDF may act as an endogenous anti-oxidant in the eye and could play a protective role against PDR.
- oxidative stress
- pigment epithelium-derived factor
- proliferative diabetic retinopathy
- total anti-oxidant capacity