S100A9 and diabetic retinopathy: Among these proteins, decreased levels of cavin2, rap1b and prdx2 were reported to be associated with insulin resistance [27], renal tubular mitochondrial dysfunction [28] and oxidative damage [29], respectively, whereas evaluated levels of Agt and s100a9 showed significant association with diabetic nephropathy [30] and diabetic retinopathy [31], respectively.