title: FABP4 dynamics in obesity: discrepancies in adipose tissue and liver expression regarding circulating plasma levels.
abstract: BACKGROUND
  FABP4 is predominantly expressed in adipose tissue, and its circulating levels are linked with obesity and a poor atherogenic profile.
  
  
  OBJECTIVE
  In patients with a wide BMI range, we analyze FABP4 expression in adipose and hepatic tissues in the settings of obesity and insulin resistance. Associations between FABP4 expression in adipose tissue and the FABP4 plasma level as well as the main adipogenic and lipolytic genes expressed in adipose tissue were also analyzed.
  
  
  METHODS
  The expression of several lipogenic, lipolytic, PPAR family and FABP family genes was analyzed by real time PCR. FABP4 protein expression in total adipose tissues and its fractions were determined by western blot.
  
  
  RESULTS
  In obesity FABP4 expression was down-regulated (at both mRNA and protein levels), with its levels mainly predicted by ATGL and inversely by the HOMA-IR index. The BMI appeared as the only determinant of the FABP4 variation in both adipose tissue depots. FABP4 plasma levels showed a significant progressive increase according to BMI but no association was detected between FABP4 circulating levels and SAT or VAT FABP4 gene expression. The gene expression of FABP1, FABP4 and FABP5 in hepatic tissue was significantly higher in tissue from the obese IR patients compared to the non-IR group.
  
  
  CONCLUSIONS
  The inverse pattern in FABP4 expression between adipose and hepatic tissue observed in morbid obese patients, regarding the IR context, suggests that both tissues may act in a balanced manner. These differences may help us to understand the discrepancies between circulating plasma levels and adipose tissue expression in obesity.
authors.affiliation: Laboratorio de Investigaciones Biomédicas del Hospital Virgen de la Victoria (Fundación IMABIS), Málaga, Spain.
authors.forename: María Isabel
authors.initials: MI
authors.lastname: Queipo-Ortuño
authors.forename: Xavier
authors.initials: X
authors.lastname: Escoté
authors.forename: Victoria
authors.initials: V
authors.lastname: Ceperuelo-Mallafré
authors.forename: Lourdes
authors.initials: L
authors.lastname: Garrido-Sanchez
authors.forename: Merce
authors.initials: M
authors.lastname: Miranda
authors.forename: Mercedes
authors.initials: M
authors.lastname: Clemente-Postigo
authors.forename: Rafael
authors.initials: R
authors.lastname: Pérez-Pérez
authors.forename: Belen
authors.initials: B
authors.lastname: Peral
authors.forename: Fernando
authors.initials: F
authors.lastname: Cardona
authors.forename: Jose Manuel
authors.initials: JM
authors.lastname: Fernández-Real
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Tinahones
authors.forename: Joan
authors.initials: J
authors.lastname: Vendrell
mesh_terms: D017667:Adipocytes / Q000378:metabolism / Q000473:pathology; D000273:Adipose Tissue / Q000378:metabolism* / Q000473:pathology; D000328:Adult; D000818:Animals; D000886:Anthropometry; D002469:Cell Separation; D015331:Cohort Studies; D004195:Disease Models, Animal; D050556:Fatty Acid-Binding Proteins / Q000097:blood* / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: C493410:FABP4 protein, human; C493411:Fabp4 protein, mouse; D050556:Fatty Acid-Binding Proteins; D012333:RNA, Messenger