Biomarkers of Kidney Disease in Horses: A Review of the Current Literature.
Authors: Galen Gaby van, Olsen Emil, Siwinska Natalia
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Biomarkers of Kidney Disease in Horses Creatinine, the standard kidney function marker in equine practice, fails to detect renal disease until 60–75% of glomerular filtration capacity has already been lost, prompting investigation into alternative biomarkers that might enable earlier diagnosis. Van, Olsen and Siwinska conducted a systematic literature review examining emerging equine kidney biomarkers, evaluating their validation protocols, reference ranges, and suitability for clinical application. Whilst symmetric dimethylarginine (SDMA) showed promise, the evidence base does not demonstrate clear advantages over creatinine for acute kidney injury (AKI) detection; conversely, cystatin C, podocin and neutrophil gelatinase-associated lipocalin (NGAL) demonstrated potential for earlier AKI identification than creatinine and warrant further investigation, with NGAL additionally showing inflammatory marker properties, whereas neutrophil gelatinase-associated lipocalin (NGAL) also showed promise as an inflammatory marker. Currently, insufficient evidence exists to support routine clinical use of any biomarker except SDMA, which can now be measured commercially; however, practitioners should remain alert to evolving research, particularly regarding cystatin C and NGAL, as these may eventually allow detection of subclinical renal dysfunction and earlier intervention in at-risk horses. Substantial additional research across diverse equine populations is essential before these emerging biomarkers can be integrated into standard diagnostic protocols.
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Practical Takeaways
- •Do not rely on creatinine alone for early detection of kidney problems—by the time creatinine is elevated, significant kidney function has already been lost
- •SDMA is the only new biomarker currently available for clinical use, though it does not yet outperform creatinine for detecting acute kidney injury
- •Emerging biomarkers like cystatin C and NGAL show promise for earlier disease detection, but are not yet ready for routine clinical practice pending additional research and validation
Key Findings
- •Creatinine fails to detect kidney disease until 60-75% of glomerular function is lost, making it an inadequate early detection marker
- •SDMA shows potential but offers no clear advantage over creatinine for AKI detection in horses based on current evidence
- •Cystatin C and podocin demonstrate potential for earlier AKI detection than creatinine and warrant further study
- •NGAL shows promise as both an early kidney disease biomarker and inflammatory marker, but only SDMA is currently validated for clinical measurement