Increased osteopontin levels in the vitreous of patients with diabetic retinopathy

Purpose: Osteopontin ( OPN) has diverse functions such as cell adhesion, chemoattraction, immunomodulation, and angiogenesis. The aim of this study is to analyze the OPN levels in vitreous fluid obtained from diabetic retinopathy ( DR) and non- DR patients. Methods: Nineteen patients out of 11 with DR and 8 without DR underwent pars plana vitrectomy and vitreous fluid was obtained simultaneously. Two distinct sandwich enzyme- linked immunosorbent assay systems ( systems 1 and 2) were applied, which have been developed in our laboratories to quantify the OPN concentrations in vitreous fluid. Results: The non- thrombin- cleaved full- length OPN levels in the vitreous fluid were 921.63 8 45.38 ng/ ml in DR and 632.80 +/- 83.43 ng/ ml in non- DR using system 1. Also, vitreous thrombin- cleaved and noncleaved OPN levels were increased to 2,109.22 +/- 151.651 and 1,651.13 +/- 229.82 ng/ ml in patients with DR and non- DR using system 2. The vitreous OPN levels were significantly higher in DR than those in non- DR ( p < 0.01 by system 1 and p < 0.05 by system 2). Conclusion: Thrombin- cleaved and noncleaved vitreous OPN levels in patients with DR were increased compared with control subjects, suggesting that OPN plays a potential role in the pathogenesis of diabetic retinal ischemia. Copyright (c) 2007 S. Karger AG, Basel.