title: Synovial fluid metabolomics in different forms of arthritis assessed by nuclear magnetic resonance spectroscopy.
abstract: OBJECTIVE
  Currently there are no reliable biomarkers in the synovial fluid available to differentiate between septic and non-septic arthritis or to predict the prognosis of osteoarthritis, respectively. Nuclear magnetic resonance (NMR) spectroscopy is an analytical technique that allows a rapid, high throughput metabolic profiling of biological fluids or tissues.
  
  
  METHODS
  Proton (1H)-nuclear magnetic resonance (NMR) spectroscopy was performed in synovial fluid samples from patients with septic arthritis, crystal arthropathy, different forms of inflammatory arthritis or osteoarthritis (OA). The metabolic environment based on the low molecular weight components was compared in disease subsets and principal component analysis (PCA) was performed.
  
  
  RESULTS
  Fifty-nine samples from patients with OA, gout, calcium pyrophosphate disease, spondylarthritis, septic arthritis and rheumatoid arthritis (RA) were analysed. NMR yielded stable and reproducible metabolites over time. Thirty-five different metabolites as well as paracetamol and ibuprofen were identified in synovial fluid. The metabolic profile of septic arthritis assessed by PCA was distinguishable from the other samples whereas no differences were seen in OA compared to crystal-associated arthritis, RA or spondylarthritis.
  
  
  CONCLUSIONS
  1H-NMR is a fast analytic tool with possible implications in synovial fluid diagnostics. A distinctive metabolism is observed in septic arthritis whereas metabolites in OA are similar to those in inflammatory arthritis.
authors.affiliation: Department of Rheumatology, University Hospital Basel, Switzerland. thomas.huegle@unibas.ch
authors.forename: Thomas
authors.initials: T
authors.lastname: Hügle
authors.forename: Helena
authors.initials: H
authors.lastname: Kovacs
authors.forename: Ingmar A F M
authors.initials: IA
authors.lastname: Heijnen
authors.forename: Thomas
authors.initials: T
authors.lastname: Daikeler
authors.forename: Ulrich
authors.initials: U
authors.lastname: Baisch
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Hicks
authors.forename: Victor
authors.initials: V
authors.lastname: Valderrabano
mesh_terms: D001168:Arthritis / Q000188:drug therapy / Q000378:metabolism*; D001170:Arthritis, Infectious / Q000378:metabolism; D001172:Arthritis, Rheumatoid / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D006073:Gout / Q000378:metabolism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D055432:Metabolomics / Q000379:methods*; D008970:Molecular Weight; D015999:Multivariate Analysis; D010003:Osteoarthritis / Q000378:metabolism; D019152:Paracentesis; D010865:Pilot Projects; D025341:Principal Component Analysis; D025242:Spondylarthropathies / Q000378:metabolism; D013582:Synovial Fluid / Q000378:metabolism*
chemical_list: D015415:Biomarkers