Figure 4.

Detection of novel biomarkers in human. (A) Secreted proteins (CHI3L1, TROP2, TPA, CK20) were elevated in most human iAKI urine but not in most vAKI urine. Conversely, secreted protein PAPPA2 was elevated in many vAKI urines, and some normal urines, but it is degraded in iAKI patients. Blue bars denote canonical molecular weights of the analyte. (B) Secreted proteins (NGAL, VDBP, TIMP2, IGFBP7) are shown for comparison and demonstrate different degrees of specificity of iAKI patients, as listed. Blue bars denote canonical molecular weights of the analyte. (C) Proteolysis of vAKI urinary PAPPA2 by iAKI urine was rescued by protease inhibitors, pepstatin A, or combinations of inhibitors. PAPPA2 was also degraded by cathepsin D.