Plasma NMR metabolomics reveals a powerful multi-marker signature in canine inflammatory conditions

BACKGROUND Identifying inflammatory states is crucial in veterinary diagnostic workups. While biomarkers for acute inflammation are widely utilized, there is a lack of reliable markers for chronic inflammation. OBJECTIVES This study aims to characterize metabolic alterations associated with common inflammatory diseases in dogs and evaluate the efficacy of metabolic markers in identifying inflammatory states. ANIMALS Plasma samples from 175 healthy dogs and 207 dogs diagnosed with specific acute and chronic diseases were collected during veterinary visits. Conditions studied included acute gastroenteritis, pyometra, neoplastic diseases, atopic dermatitis, periodontitis, urinary tract infections, canine infectious respiratory disease complex, and osteoarthritis. METHODS Samples were analyzed using a canine-validated 1H NMR spectroscopy platform. Logistic regression was employed to identify both general and disease-specific metabolic alterations. A multivariable metabolite model was developed, and its diagnostic performance was compared against C-reactive protein (CRP), albumin, glycoprotein acetyls (GlycA), and a combination of GlycA and albumin. RESULTS Metabolic changes were observed across all conditions studied, with some alterations specific to individual diseases and others common across conditions. The multivariable metabolite model demonstrated excellent overall diagnostic performance (AUC = 0.82; 95% CI: 0.78–0.86). Importantly, this model detected inflammation significantly better (p < 0.05) than CRP in all chronic diseases (AUC range: 0.68–0.89 vs. 0.46–0.60) and acute gastroenteritis (AUC: 0.86 vs. 0.71). Furthermore, it consistently showed higher AUC values compared to CRP in all diseases analyzed. CONCLUSIONS Metabolic profiling can effectively detect both acute and chronic inflammation in dogs. This approach appears superior to CRP, particularly for identifying chronic inflammatory conditions.