title: Increased toll-like receptor activity in patients with metabolic syndrome.
abstract: OBJECTIVE
  The metabolic syndrome (MetS) is highly prevalent and confers an increased risk for diabetes and cardiovascular disease (CVD). While MetS is a proinflammatory state, there is a paucity of data on cellular inflammation in MetS. Toll-like receptors (TLRs) are classical pattern recognition receptors of the innate immune response.
  
  
  METHODS
  The aim of this study was to examine monocyte TLR2 and TLR4 in MetS patients without diabetes or CVD and control subjects since both of the receptors have been implicated in atherosclerosis and insulin resistance. Fasting blood was obtained for TLR expression and activity.
  
  
  RESULTS
  Circulating levels of high-sensitivity C-reactive protein, interleukin (IL)-1β, IL-6, IL-8, and soluble tumor necrosis factor receptor 1 (sTNFR1) were significantly increased in MetS versus control subjects following adjustment for waist circumference. There was a significant increase in both TLR2 and TLR4 surface expression and mRNA on monocytes after adjustment for waist circumference. In addition to increased nuclear factor-κB nuclear binding, there was significantly increased release of IL-1β, IL-6, and IL-8 in MetS versus control subjects following priming of the monocytes with lipopolysaccharides. While both plasma free fatty acids and endotoxin were increased in MetS, they correlated significantly with TLR4 only.
  
  
  CONCLUSIONS
  In conclusion, we make the novel observation that both TLR2 and TLR4 expression and activity are increased in the monocytes of patients with MetS and could contribute to increased risk for diabetes and CVD.
authors.affiliation: Laboratory of Atherosclerosis and Metabolic Research, University of California Davis Medical Center, Sacramento, California, USA. ijialal@ucdavis.edu
authors.forename: Ishwarlal
authors.initials: I
authors.lastname: Jialal
authors.forename: Beverley A
authors.initials: BA
authors.lastname: Huet
authors.forename: Harmeet
authors.initials: H
authors.lastname: Kaur
authors.forename: Alexander
authors.initials: A
authors.lastname: Chien
authors.forename: Sridevi
authors.initials: S
authors.lastname: Devaraj
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D008055:Lipids / Q000097:blood; D024821:Metabolic Syndrome / Q000097:blood / Q000378:metabolism* / Q000473:pathology; D008875:Middle Aged; D009000:Monocytes / Q000166:cytology / Q000473:pathology; D051195:Toll-Like Receptor 2 / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D051193:Toll-Like Receptors / Q000378:metabolism*; D015854:Up-Regulation; D055105:Waist Circumference / Q000502:physiology; D055815:Young Adult
chemical_list: D008055:Lipids; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors