title: The level of fatty acid-binding protein 4, a novel adipokine, is increased in rheumatoid arthritis and correlates with serum cholesterol levels.
abstract: OBJECTIVE
  To assess the expression of the novel adipokine Fatty Acid Binding Protein-4 (FABP4) in synovial tissues, serum and the synovial fluid of patients with rheumatoid arthritis (RA) and osteoarthritis (OA) and to study the relationships among FABP4, disease activity and metabolic status.
  
  
  METHODS
  FABP4 levels were measured in the serum and synovial fluid of 40 patients with RA and 40 control patients with OA. The disease activity score (DAS28), C-reactive protein (CRP) levels and serum lipids were assessed in patients with RA. Immunohistochemical analysis and confocal microscopy were used to study the expression and cell-specific distribution of FABP4 in synovial tissues.
  
  
  RESULTS
  The age, sex and body mass index (BMI) adjusted levels of FABP4 were significantly higher in the serum (p=0.001) and synovial fluid (p=0.005) of patients with RA when compared to OA patients. FABP4 levels were higher in females than in males and correlated positively with body mass index (BMI) in patients with RA. Independent of confounders, FABP4 levels correlated with total cholesterol and LDL cholesterol in patients with RA, but not in OA patients. FABP4 levels were not affected by disease activity. Furthermore, the increased expression of FABP4 that was otherwise restricted to synovial fibroblasts, macrophages and B-cells was noted in RA patients at levels higher than that observed in OA patients.
  
  
  CONCLUSIONS
  The observed elevation of FABP4 levels in RA patients and the positive correlation of the adipokine to cholesterol suggest that FABP4 may represent a potential link between RA and the increased risk of atherosclerotic changes.
authors.affiliation: Institute of Rheumatology and Department of Rheumatology, 1st Faculty of Medicine, Charles University, Na Slupi 4, 128 50 Prague 2, Czech Republic.
authors.forename: Lucie
authors.initials: L
authors.lastname: Andrés Cerezo
authors.forename: Markéta
authors.initials: M
authors.lastname: Kuklová
authors.forename: Hana
authors.initials: H
authors.lastname: Hulejová
authors.forename: Zdeňka
authors.initials: Z
authors.lastname: Vernerová
authors.forename: Vlasta
authors.initials: V
authors.lastname: Pešáková
authors.forename: Ondřej
authors.initials: O
authors.lastname: Pecha
authors.forename: David
authors.initials: D
authors.lastname: Veigl
authors.forename: Martin
authors.initials: M
authors.lastname: Haluzík
authors.forename: Karel
authors.initials: K
authors.lastname: Pavelka
authors.forename: Jiří
authors.initials: J
authors.lastname: Vencovský
authors.forename: Ladislav
authors.initials: L
authors.lastname: Senolt
mesh_terms: D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000378:metabolism*; D001402:B-Lymphocytes / Q000378:metabolism; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism; D002784:Cholesterol / Q000097:blood*; D050556:Fatty Acid-Binding Proteins / Q000097:blood*; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D008055:Lipids / Q000097:blood; D008264:Macrophages / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000097:blood / Q000378:metabolism; D013582:Synovial Fluid / Q000166:cytology / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: C493410:FABP4 protein, human; D050556:Fatty Acid-Binding Proteins; D008055:Lipids; D002097:C-Reactive Protein; D002784:Cholesterol
keywords: FABP4; Inflammation; Lipid profile; Rheumatoid arthritis