CST3 and acute kidney injury: As there are 3 groups of AKI biomarkers: indicators of renal function (low molecular weight proteins such as Cystatin C) [69], indicators of tubular damage (urinary neutrophil gelatinase-associated lipocalin (NGAL) and urinary kidney injury molecule-1 (KIM-1)) [8] and renal inflammatory mediators (leukocytes and prostaglandins) [70].