LCN2 and chronic kidney disease: The increase in plasma concentration and urinary excretion of NGAL that accompanies the decrease of GFR may be determined by an increase of its extra-renal production, justified by the proinflammatory status of CKD and/or by its increased production by inflamed tubular cells in CKD patients, as suggested by the forest fire theory proposed by Mori and Nakao [42].