NTN1 and acute kidney injury: Novel markers of AKI are emerging such as neutrophil gelatin-associated lipocalin (NGAL), cystatin C, interleukin 18 (IL-18), kidney injury molecule 1 (KIM-1), L-type fatty acid binding protein (L-FABP), netrin 1, N-acetyl-beta-D-glucosaminidase (NAG), alfa1-macroglobulin.