Elevated serum fetuin-A levels are associated with grades of retinopathy in type 2 diabetic patients

Fetuin-A is a physiological inhibitor of insulin receptor tyrosine kinase and thus associated with insulin resistance, metabolic syndrome, and an increased risk for type 2 diabetes mellitus (T2DM). This study aims to investigate the possible relation between the serum fetuin-A levels and the stages of diabetic retinopathy (DR) in patients with T2DM.

This prospective study included 82 patients with T2DM and 19 age- and gender-matched healthy controls (HCs) (group 1). Diabetic patients were subclassified into three groups according to ocular findings: without DR (group 2; n = 26); non-proliferative DR (group 3; n = 29), and proliferative DR (group 4; n = 27). Serum fetuin-A levels were determined by a spectrophotometric technique using an immulite chemiluminescent immunometric assay. The data were analyzed using a Mann–Whitney U test, and the results were expressed as mean ± standard deviation.

Mean fetuin-A values were 256.4 ± 21.3 μg/ml in group 1, 263.5 ± 24.2 μg/ml in group 2, 282.2 ± 31.1 μg/ml in group 3, and 296.3 ± 26.2 μg/ml in group 4. Group 2 had higher mean fetuin-A level compared with group 1, but the difference was not statistically significant (p > 0.05). Serum fetuin-A levels were significantly higher in groups 3 and 4 compared with HCs (both p < 0.05). Compared with group 2, both DR groups had higher fetuin-A levels with a significant difference (both p < 0.05); and patients with proliferative DR had significantly higher serum fetuin-A levels compared with non-proliferative DR (p < 0.05). The mean serum fetuin-A levels increased with the stage of DR, and the highest levels were found in patients with proliferative DR.

Our findings suggest an association between fetuin-A levels and DR stage. In diabetic patients, the risk of retinopathy development increases with higher fetuin-A values. Fetuin-A may play an important role in the pathophysiology and progression of DR.