Metabolomic analysis of synovial fluid from Thoroughbred racehorses diagnosed with palmar osteochondral disease using magnetic resonance imaging

Abstract

Summary Background Palmar osteochondral disease (POD) is a common cause of lameness in competition horses. Magnetic resonance imaging (MRI) is the most sensitive diagnostic modality currently available, however it may not be financially or logistically practical for routine screening of POD. There is increasing interest in the use of metabolomics for diagnosis prior to progression to irreversible damage. Objectives To determine metabolite levels in synovial fluid (SF) of horses with a clinical diagnosis of POD based on diagnostic analgesia and MRI, with the hypothesis that metabolomic profiles differ between diseased and healthy joints. Study design Prospective clinical study. Methods Synovial fluid was collected from metacarpo/tarsophalangeal joints (MC/TPJ) of 29 horses (n = 51 joints), including 14 controls (n = 26) and 15 cases (n = 25), the latter with lameness localised to the MC/TPJ and MR changes consistent with POD (n = 23). Spectra were produced using 1H‐nuclear magnetic resonance (NMR) spectroscopy and analysed. Results Twenty‐five metabolites were recognised associated with various biosynthetic and degradation pathways. The metabolite abundances within the controls demonstrated increased variability compared with the clinical group. The low level of variance between the spectra of the two groups was explained by five principal components. Cross‐validation of the cohort demonstrated modest separation of predictive power (R2 = 0.67; Q2 = 0.34). Although statistical significance was not achieved, the most influential metabolites were glucose and lactate. Main limitations The modest sample size and variation in signalment, background and presenting condition of the controls may have impacted the discriminative power of the constructed models. The lack of matched controls, differences in time of fluid collection and freezing times may have also reduced accuracy when representing metabolite profiles. Conclusions This study identified and quantified metabolites present in MC/TPJ SF of clinical cases with POD.

Ex Vivo Equine Cartilage Explant Osteoarthritis Model: A Metabolomics and Proteomics Study

“… 40 1 H NMR analysis has previously been used to investigate OA in the SF of humans, horses, pigs, and dogs. 9 , 41 − 47 Synovial metabolites alanine, choline, creatine, and glucose have been identified as differentially abundant in OA across multiple studies and species. 9 , 41 , 43 − 46 NMR techniques have also previously been used to characterize the cartilage with high-resolution magical angle spinning (HRMAS) NMR utilized to assess the enzymatic degradation of bovine cartilage.…”

Metabolism and global protein glycosylation are differentially expressed in healthy and osteoarthritic equine carpal synovial fluid

“…Multivariate separation was driven primarily by higher glucose, in addition to other metabolites such as higher acetate, glycine, citrate, creatinine and alanine and lower glycylproline in cases with OA or osteochondrosis when compared to sepsis 11 . 1 H‐NMR spectroscopy of equine synovial fluid from clinical cases with MRI‐diagnosed POD lesions found glucose and lactate to be the most influential metabolites between POD and control joints, though statistical significance was not achieved 12 . Analysis of synovial fluid is of particular interest for investigation of joint diseases such as OA since it is directly in contact with the tissues of interest, including the synovial membrane and articular cartilage surface, thereby providing site‐specific metabolic data as compared to blood or urine.…”

“…Metabolic pathways related to inflammation, 7 energy metabolism in synovial fluid 8 and oxidative stress in serum 9 are commonly deranged in both human OA and rheumatoid arthritis (RA). Thus far, equine synovial fluid metabolomic analyses have been restricted to targeted lipidomics studies, 10 differentiation of septic and nonseptic joint pathologies 11 and metabolomic assessment of fetlock palmar osteochondral disease (POD) in parallel with MRI 12 . A targeted lipidomics study investigating eicosanoid release in lipopolysaccharide‐induced equine synovitis revealed a reduction in inflammatory mediators, including prostaglandin E2, following treatment with meloxicam 10 .…”

Expression of select mRNA in Thoroughbreds with catastrophic racing injuries

“…Alternatively, others have suggested using genetic screening or predictive modelling to identify those horses at greatest risk for catastrophic injuries, 4,[32][33][34] though the utility of these approaches have yet to be proven. While the detection of biomarkers for equine injuries has also been explored, [35][36][37][38][39] their use has not been widely adopted, despite some reported success. 40,41 Nevertheless, this overall shift from retrospective examination to a more proactive application of research signals a positive move towards catastrophic injury prevention, especially given recent headlines and negative attention regarding catastrophic injuries in North America.…”