title: Reduced plasma visfatin/pre-B cell colony-enhancing factor in obesity is not related to insulin resistance in humans.
abstract: BACKGROUND
  Visfatin was recently identified as a protein highly expressed and secreted in adipose tissue with insulin-mimetic effect and is a candidate hormone to help explain the association among adipose tissue expansion, insulin resistance, and type 2 diabetes.
  
  
  OBJECTIVE
  The objective of the study was to assess expression of visfatin in lean and obese subjects and in sc and visceral adipose tissue and moreover to explore the role of visfatin on insulin resistance in humans.
  
  
  METHODS
  We measured circulating visfatin and its mRNA expression in sc adipose tissue (SAT) in lean and obese subjects. Furthermore, we measured visfatin mRNA in visceral adipose (VAT) and SAT by quantitative RT-PCR. Finally, plasma visfatin and its mRNA in SAT were measured under free fatty acid-induced insulin resistance in healthy subjects.
  
  
  RESULTS
  Plasma visfatin and its mRNA in SAT were significantly lower in obese subjects, compared with normal-weight controls. Both circulating visfatin and SAT visfatin mRNA were negatively correlated with body mass index, whereas no correlation was found with homeostasis model assessment. Significantly higher visfatin mRNA was found in VAT of obese subjects, compared with lean controls. Interestingly, visfatin mRNA in VAT was positively correlated with BMI. Elevation of free fatty acid induced a condition of insulin resistance but did not affect either circulating visfatin or its mRNA.
  
  
  CONCLUSIONS
  Our findings show that, in human obesity, plasma visfatin is reduced, whereas visfatin mRNA is differentially regulated in SAT and VAT. Visfatin is not related to insulin resistance either as assessed by homeostasis model assessment or during lipid infusion.
authors.affiliation: Endocrine-Metabolic Laboratory, Department of Medical and Surgical Sciences, University of Padua, Via ospedale 105, 35100 Padua, Italy. claudio.pagano@unipd.it
authors.forename: Claudio
authors.initials: C
authors.lastname: Pagano
authors.forename: Catia
authors.initials: C
authors.lastname: Pilon
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Olivieri
authors.forename: Paola
authors.initials: P
authors.lastname: Mason
authors.forename: Roberto
authors.initials: R
authors.lastname: Fabris
authors.forename: Roberto
authors.initials: R
authors.lastname: Serra
authors.forename: Gabriella
authors.initials: G
authors.lastname: Milan
authors.forename: Marco
authors.initials: M
authors.lastname: Rossato
authors.forename: Giovanni
authors.initials: G
authors.lastname: Federspil
authors.forename: Roberto
authors.initials: R
authors.lastname: Vettor
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry; D000328:Adult; D016207:Cytokines / Q000097:blood* / Q000235:genetics; D005217:Fat Emulsions, Intravenous; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D050152:Intra-Abdominal Fat / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D054409:Nicotinamide Phosphoribosyltransferase; D009765:Obesity / Q000097:blood* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050151:Subcutaneous Fat / Q000737:chemistry
chemical_list: D016207:Cytokines; D005217:Fat Emulsions, Intravenous; D005230:Fatty Acids, Nonesterified; D012333:RNA, Messenger; D054409:Nicotinamide Phosphoribosyltransferase; C085455:nicotinamide phosphoribosyltransferase, human