Positive correlation of pigment epithelium-derived factor and total antioxidant capacity in aqueous humour of patients with uveitis and proliferative diabetic retinopathy

Abstract

Background/aims: There are several animal studies to suggest that pigment epithelium-derived factor (PEDF) may exert beneficial effects on diabetic retinopathy and uveitis by acting as an endogenous antioxidant. However, the interrelationship between PEDF and total antioxidant capacity in the human eye remains to be elucidated. In this study, PEDF and total antioxidant levels were determined in the aqueous humour of patients with proliferative diabetic retinopathy (PDR) and uveitis, and the relationship between these two markers was investigated. Methods: Aqueous humour levels of PEDF and total antioxidant capacity were determined by an ELISA system in 34 uveitis and 9 PDR samples. Results: Aqueous humour levels of PEDF and total antioxidant capacity were significantly lower in patients with PDR than those with uveitis (1.8 ± 0.2 μg/ml vs 6.4 ± 0.8 μg/ml and 0.17 ± 0.03 mmol/l vs 0.85 ± 0.05 mmol/l, respectively, p<0.01). A positive correlation between PEDF and total antioxidant capacity was found in patients with PDR and uveitis (r = 0.33, p<0.05). Conclusion: This study demonstrated that PEDF levels were associated with total antioxidant capacity in aqueous humour levels in humans. These observations suggest that substitution of PEDF may be a therapeutic target for oxidative stress-involved eye diseases, especially PDR.