Canine leishmaniosis, caused by Leishmania infantum, is a zoonotic disease often leading to chronic kidney disease (CKD). Early detection of renal damage is critical for prognosis and treatment, as conventional biomarkers, such as serum creatinine and symmetric dimethylarginine (SDMA), are inadequate for detecting early stages of renal dysfunction. This study evaluates the urinary gamma-glutamyl transferase-to-creatinine ratio (uGGT/c) as an early biomarker for renal injury in dogs with leishmaniosis, including 17 healthy dogs and 77 dogs with leishmaniosis, categorized using the International Renal Interest Society (IRIS) guidelines. Plasma and urinary parameters, including uGGT/c, were analyzed. Elevated uGGT/c ratios were observed in over 50% of non-azotemic and non-proteinuric dogs and all dogs with mild-to-moderate proteinuria. The uGGT/c ratio demonstrated a 90.4% sensitivity and 80% specificity for early detection of renal tubular damage, outperforming plasma creatinine (44.2%) and SDMA (51.9%). The uGGT/c ratio correlated strongly with proteinuria (UPC; r = 0.716, p < 0.001) and SDMA (r = 0.591, p < 0.001), indicating its usefulness as an early indicator of renal dysfunction. Despite the small sample size, the implementation of the uGGT/c ratio as promising biomarker could improve early diagnosis and clinical intervention, helping to avoid irreversible renal damage in dogs affected by leishmaniosis.

Myxomatous mitral valve disease (MMVD) is the most common acquired heart valve disease in dogs and it may contribute to cardiovascular–renal axis disorders (CvRD) in dogs. Sensitive and early biomarkers of renal involvement are needed. In this prospective and observational study, 84 dogs were enrolled (20 healthy dogs and 64 dogs with MMVD), categorised using the American College of Veterinary Internal Medicine guidelines. Serum and urinary parameters were analysed, including tubular biomarkers expressed as creatinine-ratios: urinary alkaline phosphatase (uALPc), gamma-glutamyl transferase (uGGTc), N-acetyl-β-D-glucosaminidase (uNAGc), and cystatin C (uCystc). uALPc, uGGTc, and uNAGc were higher in MMVD than in controls; uALPc and uGGTc were increased from stage B1, uNAGc was higher in stages with cardiomegaly (B2 and C+D), and uCystc increased mainly in clinical stages (C+D). Serum renal markers increased only in clinical stages. ROC analysis showed good discrimination for MMVD with uALPc (AUC 0.87) and uGGTc (0.86); for cardiomegaly with uALPc (0.77) and uNAGc (0.75); and for congestive heart failure with SDMA (0.85) and uCystc (0.75). No urinary biomarker was associated with daily furosemide dose. Urinary tubular biomarkers, particularly uALPc and uGGTc, detect early CvRD in dogs with MMVD and complement traditional serum markers.

Myxomatous mitral valve disease (MMVD) is the most common acquired heart valve disease in dogs and it may contribute to cardiovascular-renal axis disorders (CvRD) in dogs. Sensitive and early biomarkers of renal involvement are needed. In this prospective and observational study, 84 dogs were enrolled (20 healthy dogs and 64 dogs with MMVD, categorized using the American College of Veterinary Internal Medicine guidelines. Serum and urinary parameters were analyzed, including tubular biomarkers expressed as creatinine-ratios: urinary alkaline phosphatase (uALPc), gamma-glutamyl transferase (uGGTc), N-acetyl-β-D-glucosaminidase (uNAGc) and cystatin C (uCystc). uALPc, uGGTc and uNAGc were higher in MMVD than in controls; uALPc and uGGTc were increased from stage B1, uNAGc was higher in stages with cardiomegaly (B2 and C+D), and uCystc increased mainly in clinical stages (C+D). Serum renal markers increased only in clinical stages. ROC analysis showed good discrimination for MMVD with uALPc (AUC 0.87) and uGGTc (0.86); for cardiomegaly with uALPc (0.77) and uNAGc (0.75); and for congestive heart failure with SDMA (0.85) and uCystc (0.75). No urinary biomarker was associated with daily furosemide dose. Urinary tubular biomarkers, particularly uALPc and uGGTc, detect early CvRD in dogs with MMVD and complement traditional serum markers.