However, Fgf21−/− CKD mice exhibited severer renal tubular damage and inflammation than wild-type CKD mice as determined by expression levels of osteopontin, neutrophil gelatinase-associated lipocalin (Ngal), and monocyte chemotactic protein-1 (MCP1) (Fig. 1d–f). This evidence concerns the gene SPP1 and chronic kidney disease.