title: Metabolomics in psoriatic disease: pilot study reveals metabolite differences in psoriasis and psoriatic arthritis.
abstract: OBJECTIVE
  While "omics" studies have advanced our understanding of inflammatory skin diseases, metabolomics is mostly an unexplored field in dermatology.
  
  
  OBJECTIVE
  We sought to elucidate the pathogenesis of psoriatic diseases by determining the differences in metabolomic profiles among psoriasis patients with or without psoriatic arthritis and healthy controls.
  
  
  METHODS
  We employed a global metabolomics approach to compare circulating metabolites from patients with psoriasis, psoriasis and psoriatic arthritis, and healthy controls.
  
  
  METHODS
  Study participants were recruited from the general community and from the Psoriasis Clinic at the University of California Davis in United States.
  
  
  METHODS
  We examined metabolomic profiles using blood serum samples from 30 patients age and gender matched into three groups: 10 patients with psoriasis, 10 patients with psoriasis and psoriatic arthritis and 10 control participants. Main outcome(s) and measures(s): Metabolite levels were measured calculating the mean peak intensities from gas chromatography time-of-flight mass spectrometry.
  
  
  RESULTS
  Multivariate analyses of metabolomics profiles revealed altered serum metabolites among the study population. Compared to control patients, psoriasis patients had a higher level of alpha ketoglutaric acid (Pso: 288 ± 88;
  
  
  METHODS
  209 ± 69; p=0.03), a lower level of asparagine (Pso: 5460 ± 980;
  
  
  METHODS
  7260 ± 2100; p=0.02), and a lower level of glutamine (Pso: 86000 ± 20000;
  
  
  METHODS
  111000 ± 27000; p=0.02). Compared to control patients, patients with psoriasis and psoriatic arthritis had increased levels of glucuronic acid (Pso + PsA: 638 ± 250;
  
  
  METHODS
  347 ± 61; p=0.001). Compared to patients with psoriasis alone, patients with both psoriasis and psoriatic arthritis had a decreased level of alpha ketoglutaric acid (Pso + PsA: 186 ± 80; Pso: 288 ± 88; p=0.02) and an increased level of lignoceric acid (Pso + PsA: 442 ± 280; Pso: 214 ± 64; p=0.02).
  
  
  CONCLUSIONS
  The metabolite differences help elucidate the pathogenesis of psoriasis and psoriatic arthritis and they may provide insights for therapeutic development.
authors.affiliation: Department of Dermatology, University of Colorado Denver, Aurora, CO, 12801, USA.
authors.forename: April W
authors.initials: AW
authors.lastname: Armstrong
authors.affiliation: Department of Dermatology, University of Colorado Denver, Aurora, CO, 12801, USA.
authors.forename: Julie
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Dermatology, University of California Davis, Sacramento, CA, 95816, USA.
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Johnson
authors.affiliation: NIH West Coast Metabolomics Center, University of California Davis, Davis, CA, 95616, USA.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Grapov
authors.affiliation: Department of Dermatology, University of Colorado Denver, Aurora, CO, 12801, USA.
authors.forename: Baktazh
authors.initials: B
authors.lastname: Azizi
authors.affiliation: Department of Dermatology, University of Colorado Denver, Aurora, CO, 12801, USA.
authors.forename: Jaskaran
authors.initials: J
authors.lastname: Dhillon
authors.affiliation: NIH West Coast Metabolomics Center, University of California Davis, Davis, CA, 95616, USA.
authors.forename: Oliver
authors.initials: O
authors.lastname: Fiehn