title: Adipose tissue expression of interleukin-18 mRNA is elevated in subjects with metabolic syndrome and independently associated with fasting glucose.
abstract: BACKGROUND
  The metabolic syndrome (MetS) is a cluster of risk factors that are highly associated with increased risk for cardiovascular disease (CVD). Increased serum levels of plasminogen activator inhibitor-1 (PAI-1), interleukin-6 (IL-6) and IL-18 have been reported to be associated with CVD. Recently, IL-18 has been shown to be predictive for cardiovascular events in subjects with MetS. We have investigated the expression of PAI-1, IL-6 and IL-18 in subcutaneous adipose tissue (AT) of subjects with (n = 22) and without (n = 36) MetS. Furthermore, we have analysed the expression of IL-18 in monocyte-derived macrophages (MDMs) in an in vitro model of hyperglycaemia.
  
  
  METHODS
  We studied the expression of PAI-1, IL-6 and IL-18 in biopsies of subcutaneous adipose tissue using Real-time PCR. After isolation and cultivation of MDMs, expression of IL-18 was determined by Real-time PCR.
  
  
  RESULTS
  Expression of IL-18 was increased in subcutaneous AT of subjects with MetS (p < 0.05). Multivariate analysis revealed fasting plasma glucose to be the only MetS component being independently associated with expression of IL-18 in AT (p < 0.05). Exposure to hyperglycaemia, increased in expression of IL-18 in MDMs (p < 0.01).
  
  
  CONCLUSIONS
  Our findings suggest that subjects with MetS have a particular inflammatory pattern in AT, possibly driven by fasting glucose. MDMs might - at least in part - be the cellular source of this increased expression. Together with recent reports, showing IL-18 to be predictive for cardiovascular events, our findings could provide the basis for further research of the role of IL-18 as a link and possible target in the association between MetS and atherosclerosis.
authors.affiliation: Centre for Clinical Heart Research, Department of Cardiology, Oslo University Hospital, Ulleval, Oslo, Norway. thomas.weiss@meduniwien.ac.at
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Weiss
authors.forename: Harald
authors.initials: H
authors.lastname: Arnesen
authors.forename: Marius
authors.initials: M
authors.lastname: Trøseid
authors.forename: Christoph
authors.initials: C
authors.lastname: Kaun
authors.forename: Elsa M
authors.initials: EM
authors.lastname: Hjerkinn
authors.forename: Kurt
authors.initials: K
authors.lastname: Huber
authors.forename: Johann
authors.initials: J
authors.lastname: Wojta
authors.forename: Ingebjorg
authors.initials: I
authors.lastname: Seljeflot
mesh_terms: D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D015897:Comorbidity; D005215:Fasting; D005260:Female; D006801:Humans; D007249:Inflammation / Q000453:epidemiology* / Q000378:metabolism*; D020382:Interleukin-18 / Q000235:genetics / Q000378:metabolism*; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology* / Q000378:metabolism*; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D015995:Prevalence; D012333:RNA, Messenger / Q000378:metabolism; D018570:Risk Assessment; D012307:Risk Factors; D013223:Statistics as Topic
chemical_list: D001786:Blood Glucose; D020382:Interleukin-18; D012333:RNA, Messenger