Plasma Osteopontin Levels is Associated with Biochemical Markers of Kidney Injury in Patients with Leptospirosis.

Leptospirosis becomes severe, with a fatality rate of >10%, and manifests as severe lung injury accompanied by acute kidney injury. Using urine and blood samples of 112 patients with leptospirosis, osteopontin (OPN), galectin-9 (Gal-9) and other kidney-related biomarkers were measured to understand the pathological and diagnostic roles of OPN and Gal-9 in leptospirosis. Plasma levels of full-length (FL)-OPN (pFL-OPN) ( < 0.0001), pFL-Gal-9( < 0.0001) and thrombin-cleaved OPN ( < 0.01) were significantly higher in patients with leptospirosis than in healthy controls ( = 30), as were levels of several indicators of renal toxicity: serum cystatin C ( < 0.0001), urine -acetyl-β-glucosaminidase (NAG)/creatinine ( < 0.05), and urine clusterin/creatinine ( < 0.05). pFL-Gal-9 levels were negatively correlated with pFL-OPN levels ( = -0.24, < 0.05). pFL-OPN levels were positively correlated with serum cystatin C ( = 0.41, < 0.0001), urine NAG/creatinine ( = 0.35, < 0.001), urine clusterin/creatinine ( = 0.33, < 0.01), and urine cystatin C/creatinine ( = 0.33, < 0.05) levels. In a group of patients with abnormally high creatinine levels, significantly higher levels of serum cystatin C ( < 0.0001) and pFL-OPN ( < 0.001) were observed. Our results demonstrate that pFL-OPN reflect kidney injury among patients with leptospirosis.