title: Adipocyte fatty acid-binding protein is a plasma biomarker closely associated with obesity and metabolic syndrome.
abstract: BACKGROUND
  Adipocyte fatty acid-binding protein (A-FABP) is traditionally thought to be a cytosolic fatty acid chaperone expressed in adipocytes. Mice with targeted disruption of the A-FABP gene exhibit a striking phenotype with strong protection from insulin resistance, hyperglycemia, and atherosclerosis. The clinical relevance of these findings remains to be confirmed.
  
  
  METHODS
  We used tandem mass spectrometry-based proteomic analysis to identify proteins secreted from adipocytes and present in human serum. We measured serum A-FABP concentrations in 229 persons (121 men and 108 women; age range, 33-72 years), including 100 lean [body mass index (BMI) <25 kg/m2] and 129 overweight/obese individuals (BMI >25 kg/m2) selected from a previous cross-sectional study.
  
  
  RESULTS
  A-FABP was released from adipocytes and was abundantly present in human serum. Mean (SD) circulating concentrations of A-FABP were significantly higher in overweight/obese than in lean persons [32.3 (14.8) vs 20.0 (9.8) microg/L; P < 0.001]. Age- and sex-adjusted serum A-FABP concentrations correlated positively (P < 0.005) with waist circumference, blood pressure, dyslipidemia, fasting insulin, and the homeostasis model assessment insulin resistance index. Moreover, we observed a significant increase in A-FABP concentrations corresponding with increases in the number of components of the metabolic syndrome (P < 0.05).
  
  
  CONCLUSIONS
  A-FABP is a circulating biomarker closely associated with obesity and components of the metabolic syndrome, and measurement of serum concentrations of A-FABP might be useful for clinical diagnosis of obesity-related metabolic and cardiovascular disorders.
authors.affiliation: Department of Medicine, University of Hong Kong, Hong Kong, China. amxu@hkucc.hku.hk
authors.forename: Aimin
authors.initials: A
authors.lastname: Xu
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Jian Yu
authors.initials: JY
authors.lastname: Xu
authors.forename: David
authors.initials: D
authors.lastname: Stejskal
authors.forename: Sidney
authors.initials: S
authors.lastname: Tam
authors.forename: Jialiang
authors.initials: J
authors.lastname: Zhang
authors.forename: Nelson M S
authors.initials: NM
authors.lastname: Wat
authors.forename: Wai Keung
authors.initials: WK
authors.lastname: Wong
authors.forename: Karen S L
authors.initials: KS
authors.lastname: Lam
mesh_terms: D017667:Adipocytes / Q000378:metabolism*; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure; D050171:Dyslipidemias / Q000097:blood; D045604:Extracellular Fluid / Q000378:metabolism; D050556:Fatty Acid-Binding Proteins / Q000097:blood*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000175:diagnosis; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000175:diagnosis; D020543:Proteome / Q000032:analysis*
chemical_list: D015415:Biomarkers; D050556:Fatty Acid-Binding Proteins; D007328:Insulin; D020543:Proteome