Influence of clinical and experimental intra-articular inflammation on neutrophil gelatinase-associated lipocalin concentrations in horses.
Authors: Frydendal Catina, Nielsen Katrine B, Berg Lise C, van Galen Gaby, Adler Ditte M T, Andreassen Stine M, Jacobsen Stine
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: NGAL as a Biomarker for Equine Joint Inflammation Researchers from Copenhagen investigated whether neutrophil gelatinase-associated lipocalin (NGAL)—a protein released by activated neutrophils—could serve as a measurable indicator of joint inflammation in horses. Using both controlled experimental models and clinical case material, they measured NGAL concentrations in synovial fluid and serum from healthy horses, horses with naturally occurring septic arthritis, and horses given intra-articular injections of lipopolysaccharide (severe inflammation), lidocaine (moderate), or mepivacaine (mild) to trigger inflammatory responses of varying intensity. Synovial fluid NGAL concentrations rose dramatically following LPS injection (343-fold) and lidocaine injection (60-fold) compared to baseline, with a clear dose–response relationship to inflammation severity; critically, horses with septic arthritis showed significantly elevated synovial NGAL compared to non-septic clinical cases and healthy controls. NGAL concentrations in joint fluid correlated strongly with white blood cell counts (R² = 0.49), suggesting it genuinely reflects the inflammatory burden rather than simply rising coincidentally. For practitioners managing equine joint disease, this work indicates that synovial NGAL measurement could become a valuable objective tool for quantifying inflammation intensity and potentially distinguishing septic from non-septic arthritis, thereby refining diagnostic protocols and treatment decisions—though validation studies in larger clinical populations and optimisation of collection and assay protocols would be needed before routine implementation.
Read the full abstract on PubMed
Practical Takeaways
- •NGAL measured in synovial fluid appears useful as a diagnostic biomarker to differentiate septic from non-septic joint inflammation and assess inflammation severity
- •Synovial fluid samples are more diagnostically sensitive than serum for NGAL detection in joint disease, making joint aspiration the preferred diagnostic approach
- •NGAL concentration correlates with inflammatory cell infiltration, so it could help clinicians quantify inflammation intensity and potentially guide treatment intensity decisions
Key Findings
- •Synovial fluid NGAL concentrations increased 343-fold after LPS injection and 60-fold after lidocaine injection, showing dose-dependent response to inflammation severity
- •SF NGAL concentrations were significantly higher in horses with septic arthritis compared to non-septic cases and healthy controls (P = 0.0070)
- •NGAL concentrations in synovial fluid correlated strongly with white blood cell counts (R² = 0.49, P < 0.0001), suggesting NGAL reflects inflammatory intensity
- •Serum NGAL increased in response to joint inflammation but at lower concentrations than synovial fluid, indicating SF is the preferred diagnostic sample