CES5A and chronic kidney disease: Regarding qualitative proteinuria and proteomics, sodium-dodecyl-sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional gel electrophoresis have been applied in cats, leading to the identification of putative biomarkers of tubulointerstitial damage in feline CKD including uromodulin, cauxin and retinol binding protein (RBP) [21,22,23].