Glomerular and tubular kidney damage markers in canine babesiosis caused by Babesia canis

Canine babesiosis is a tick-borne disease caused by the haemoprotozoan parasites of the genus Babesia. The aim of this study was to assess renal dysfunction in dogs with babesiosis caused by B. canis, using serum and urinary markers for both glomerular and tubular dysfunction. Assays previously not validated for use in canine samples were validated and the potential interference of haemoglobin, lipids and bilirubin with these analyses was additionally considered. In this study 42 dogs naturally infected with B. canis and 14 healthy dogs were included. Dogs with babesiosis were divided into 3 groups: group A consisted of 9 non-azotemic dogs with normal urine protein to creatinine ratio (UPC < 0.5), group B of 27 non-azotemic dogs with UPC > 0.5 and group C of 6 azotemic dogs with UPC > 2. The concentrations of urinary immunoglobin G (IgG), retinol binding protein (RBP), uromodulin, kidney injury molecule - 1 (KIM-1), and serum symmetric dimethylarginine were measured by ELISA assays, while urinary albumin and N-acetyl-b-D-glucosaminidase (NAG) were evaluated by an immunoturbidimetric and enzymatic colorimetric assay, respectively. Urinary markers were normalized to urine creatinine concentration. All tested markers, with exception of uromodulin, showed significant differences between dogs with babesiosis and healthy dogs, and also showed strong or very strong positive correlation with UPC. Increases of urinary albumin and IgG suggested glomerular damage, and increases of KIM-1, RBP and NAG proximal tubular damage in dogs with babesiosis. They demonstrated clear advantages compared to conventional parameters by showing earlier changes in detecting renal damage.