Correlation of electrophoretic urine protein banding patterns with severity of renal damage in dogs with proteinuric chronic kidney disease

BackgroundUrine protein loss is common in dogs with chronic kidney disease (CKD). Currently available noninvasive means of evaluating CKD in dogs cannot accurately predict the severity of glomerular and tubulointerstitial damage. Electrophoretic analysis of urine proteins can indicate the compromised renal compartment (glomerular vs tubular), but extensive evaluation of protein banding pattern associations with histologic damage severity has not been performed in dogs. ObjectivesWe aimed to evaluate electrophoretic banding patterns as indicators of the presence and severity of glomerular and tubulointerstitial damage in dogs with naturally occurring, predominantly proteinuric CKD. MethodsWe performed a retrospective study using urine and renal tissue from 207 dogs with CKD. Urine protein banding patterns were correlated with histologic severity of renal damage. Sensitivity and specificity of banding patterns for the detection of glomerular and tubulointerstitial damage were determined. ResultsBanding patterns were 97% sensitive and 100% specific for the detection of glomerular damage and 90% sensitive and 100% specific for the detection of tubulointerstitial damage. Correlations between composite banding patterns and the severity of renal damage were strong, while glomerular banding patterns correlated moderately with glomerular damage severity, and tubular gel scores correlated weakly to moderately with the severity of tubulointerstitial damage. Conclusions and clinical importanceUrine protein banding patterns are useful for the detection of glomerular and tubulointerstitial damage in dogs with proteinuric CKD.