Combined Veterinary Pathology Resident/PhD Student The Ohio State University Veterinary Medical Center, Department of Veterinary Clinical Sciences Columbus, OH, United States
Abstract:
Background: Determining the cause of proteinuric renal disease in cats presents a diagnostic challenge due to the necessity of renal biopsy for definitive diagnosis. Use of urine electrophoretic protein banding patterns to determine origin and cause of renal proteinuria is underexplored in cats.
Objective: Determine the expected urine protein banding patterns of clinically healthy cats and compare with cats with biopsy-confirmed tubulointerstitial (TI) and glomerular diseases. Animals: Banked urine supernatant from 15 clinically healthy cats and 29 cats with biopsy-confirmed kidney disease: 10 stable chronic kidney disease (CKD) with TI damage; 12 immune complex-mediated glomerulonephritis (ICGN); 7 non-ICGN glomerular disease (amyloidosis, podocytopathy, focal segmental glomerulosclerosis).
Methods: Urine proteins were separated with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Low (LMW, < 36.5 kDa), intermediate (IMW, 36.5-66.3 kDa), high (HMW, 66.3-200 kDa), and very high (VHMW, >200 kDa) molecular weight bands were enumerated.
Results: Healthy cat urine contained protein bands consistent with albumin, cauxin, and uromodulin. LMW bands were significantly greater in all diseases than in healthy cats and greater in ICGN and non-ICGN glomerular diseases than CKD. IMW, HMW and VHMW bands were significantly increased in ICGN and non-ICGN cats compared to healthy and CKD cats. ICGN cats had the highest median number of VHMW bands; ≥ 3 VHMW bands was 83% sensitive and 91% specific for ICGN. (Table 1)
Conclusions: Urine SDS-PAGE differentiates cats with glomerular disease from healthy cats and cats with TI CKD and has modest to high sensitivity and specificity for identifying ICGN cats.
