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 +/- 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.