Urine protein electrophoresis analysis in dogs with systemic inflammatory response syndrome

Serum biomarkers can underestimate renal damage in dogs with systemic inflammatory response syndrome (SIRS).

To identify differences in proteinuria patterns between dogs with and without SIRS using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and evaluate its value as an early diagnostic and prognostic indicator.

Client-owned, proteinuric dogs with (n = 10) and without (n = 21) SIRS.

In this retrospective study, urine electropherograms from SDS-PAGE were used to identify and quantify low molecular weight (LMW) and high molecular weight (HMW) protein bands. The LMW/HMW ratio was calculated for each dog and analyzed for correlations with the acute patient physiologic and laboratory evaluation (APPLE) full (APPLEfull) and fast (APPLEfast) scores and death within 2, 4, and 8 weeks.

The LMW/HMW ratio and the proportion of proteins with molecular weights of 20-30 kDa were significantly higher in the SIRS than in the non-SIRS group (P < .001 and P = .018). The LMW/HMW ratio correlated with inflammatory (C-reactive protein, globulin, white blood cell, and band neutrophil counts) and renal markers (blood urea nitrogen and symmetric dimethylarginine; rho = 0.381-0.786, all P < .05). The LMW/HMW ratio showed a high predictive value for death within 2 (area under the curve [AUC] = 0.844, 95%CI, 0.597-1.091), 4 (AUC = 0.867, 95%CI, 0.682-1.041), and 8 weeks (AUC = 0.944, 95%CI, 0.802-1.087).

An increased LMW/HMW ratio, reflecting elevated LMW proteinuria, can be a reliable diagnostic and prognostic indicator for early renal damage in dogs with SIRS.