Evaluation of podocin in urine in horses using qualitative and quantitative methods.
Authors: Siwińska Natalia, Pasławska Urszula, Bąchor Remigiusz, Szczepankiewicz Barbara, Żak Agnieszka, Grocholska Paulina, Szewczuk Zbigniew
Journal: PloS one
Summary
# Editorial Summary: Podocin as an Early Marker of Equine Kidney Disease Early detection of glomerular injury in horses remains clinically challenging, yet podocin—a structural protein in the filtration barrier—shows promise as a diagnostic biomarker, having demonstrated utility in human and small animal nephrology. Researchers employed two complementary analytical approaches (liquid chromatography-tandem mass spectrometry and species-specific ELISA) to measure urinary podocin in healthy horses, animals with confirmed kidney dysfunction, and those at risk of acute kidney injury. Podocin concentrations in healthy animals ranged from 0.19–1.2 ng/ml, whilst diseased horses showed substantially elevated levels (0.29–20.0 ng/ml), with both methods producing significantly corresponding results and LC-MS-MRM proving more sensitive than ELISA. For practitioners, podocin represents a potentially valuable non-invasive screening tool for detecting glomerular disease earlier than conventional biochemical parameters; however, the occurrence of physiological podocyturia in some healthy individuals limits its specificity as a diagnostic marker, making it more useful for ruling out disease than confirming it. Further refinement of reference ranges and integration with established renal parameters would be necessary before implementing podocin assays into routine practice protocols.
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Practical Takeaways
- •Urinary podocin analysis could support early detection of kidney dysfunction in horses, potentially before clinical signs appear
- •LC-MS-MRM is the more reliable method if available, though ELISA is a practical alternative for ruling out kidney disease
- •Elevated urinary podocin warrants further investigation but cannot diagnose kidney disease on its own due to false positives in healthy horses
Key Findings
- •Podocin was detected in urine samples from healthy horses (0.19–1.2 ng/ml), horses with kidney dysfunction (0.19–20.0 ng/ml), and horses at risk for AKI (0.29–5.71 ng/ml) using ELISA
- •LC-MS-MRM and ELISA methods showed significant correlation in detecting podocin, with LC-MS-MRM being more sensitive
- •Podocin may serve as a biomarker for clinical kidney disease and glomerular injury in horses, though physiological podocyturia limits its diagnostic specificity
- •ELISA test was more effective at excluding kidney disease than confirming it