NON INVASIVE DIAGNOSTIC EVALUATION INCLUDING QUALITATITE PROTEINURIA TO DETECT AN EARLY RENAL DAMAGE IN CANINE LEISHMANIASIS

Urine markers are advocated to early detect kidney damage in the clinical practice, nevertheless histology remains the gold standard. The aim of this study was to evaluate quali-quantitative proteinuria and possible renal damage using different non-invasive tests in dogs affected by leishmaniasis.Based on clinical signs and serology/cytology, 26 affected dogs (Leish) were included. Fifteen healthy, non-proteinuric dogs were selected as Control. Upon admission, all dogs underwent to physical examination, Systolic Blood Pressure (SBP) measurement, clinicopathological evaluation (CBC, Urea, Creatinine, ALT, ALP, Glucose, Calcium, Phosphorous, Sodium, Potassium, Cholesterol, Triglyceride, Albumin, Total Protein), serology, urinalysis, ultrasound examination and Renal Resistive Index (RRI) determination. Urine Total Protein and Urine Albumin to Creatinine ratios (UPC; UAC), urine High Resolution agarose and Silver Staining Sodium-Dodecyl-Sulphate-PolyAcrylamide gel electrophoresis (HRE; SDS-PAGE) were performed. A cut-off of 66 kDa was selected to classify bands in High or Low Molecular Weight (HMW; LMW). Data were analyzed with non-parametric statistics and ROC curve analysis (ROC). A difference was considered significant for p<0.05.In 9/26 dogs Creatinine concentration was above the reference interval (Median 0.85, Mean 1.84, range 0.2- 12.8, R.I. 0.65-1.4 mg/dl) and in 15/26 the Urine Specific Gravity (USG) was < 1030 (Median 1025, Mean 1031, range 1012-1050). Proteinuria (UPC >0.5) was detected in 16/26 dogs (P), 5/26 were borderline proteinuric (BLP; UPC 0.2-0.5) and 5/26 were nonproteinuric (NP, UPC <0.2). Leish dogs presented significantly higher UPC (Mean 3, Median 1.29) and UAC (Mean 1.62, Median 0.29). RRI values were significantly higher in Leish (Mean 0.72) than Control (Mean 0.64). RRI was significantly correlated to WBC (r=0.51), Hemoglobin (r=0.52) and Albumin concentrations (r=0.61), USG (r=0.60) and UPC (r=0.48). HRE and SDSPAGE protein patterns allow to distinguish P from NP and Control dogs. SDS-PAGE revealed a significantly higher number of bands in Leish dogs (35-40) than in Control (25-30). NP and BLP dogs presented a significantly lower number of LMW bands than P. Number of bands was significantly correlated to UPC (r=0.66) and UAC (r=0.64). Using a cut-off value of 32 SDSPAGE bands to discriminate between Leish and Control, ROC showed for UPC >0.17, 89% Sensitivity and 88% Specificity and for UAC >0.013, 94% Sensitivity and 82% Specificity. The Areas under the Curve for UPC and UAC were 0.89 and 0.92, respectively. Non-invasive methods, particularly urinary SDS-PAGE, could be useful to detect an early renal damage in canine leishmaniasis. Further studies are required to correlate these findings to renal histology