Correlation between systemic S100A8 and S100A9 levels and severity of diabetic retinopathy in patients with type 2 diabetes mellitus

Abstract Aims S100A8and S100A9are myeloid-related damage-associated molecular patterns(DAMPs) primarily involved in the modulation of innate immune response to cellular injury. This study evaluated the correlation between circulating concentrations of S100A8and S100A9proteins with the severity of diabetic retinopathy (DR) in patients with type 2 diabetes (T2DM). Methods T2DM patients with HbA1c levels >7%, fasting blood glucose >126 mg/dl and history of diabetes were included in this study. DR severity was graded based on ETDRS and Gloucestershire classifications. Plasma samples were evaluated for S100A8and S100A9levels using ELISA. Results In this comparative study, DR patients (n = 89) had increased plasma S100A8and S100A9proteins compared to age-matched T2DM controls (n = 28), which was directly related to the severity of DR. Female DR subjects had increased S100A8expression compared to their male counterparts. Substantial retention of S100A8and S100A9production was seen in DR patients above 50 years of age. Duration of T2DM was not found to affect protein levels, however T2DM onset at >50 years old significantly increased S100A8and S100A9concentrations. Conclusions Our findings suggest that systemic circulationlevels of S100A8and S100A9are correlated with the progression of DR in T2DM patients, indicating their potential role in DR pathogenesis.