The association of serum and vitreous adropin concentrations with diabetic retinopathy

Objective Adropin, a newly identified regulatory protein encoded by Enho gene, is correlated with insulin sensitivity and diabetes. The aim of this study is to determine whether serum and vitreous adropin concentrations are correlated with the presence of diabetic retinopathy. Methods A population of 165 patients with type 2 diabetes mellitus (52 without diabetic retinopathy, 69 with non-proliferative diabetic retinopathy and 44 patients with proliferative diabetic retinopathy) was enrolled in this study. The control group enrolled 68 healthy subjects who had underwent vitrectomy for retinal detachment. Serum and vitreous adropin concentrations were examined using enzyme-linked immunosorbent assay method. Results Control subjects had significantly higher serum and vitreous adropin concentrations compared with diabetic patients. Serum and vitreous adropin concentrations in proliferative diabetic retinopathy patients were significantly reduced compared with those in non-proliferative diabetic retinopathy patients and type 2 diabetes mellitus patients without diabetic retinopathy. In addition, there were lower serum and vitreous adropin concentrations in non-proliferative diabetic retinopathy patients compared with type 2 diabetes mellitus patients without diabetic retinopathy. Logistic regression analysis revealed that serum and vitreous adropin were associated with a decreased risk of type 2 diabetes mellitus and diabetic retinopathy. Conclusion Serum and vitreous adropin concentrations are negatively associated with the presence of diabetic retinopathy.