title: Periodic vs constant high glucose in inducing pro-inflammatory cytokine expression in human coronary artery endothelial cells.
abstract: OBJECTIVE
  Fluctuating hyperglycemia exerts a more deleterious effect than constant hyperglycemia on cardiovascular outcome in diabetic patients. We investigated the inflammatory responses of human coronary artery endothelial cells (HCAECs) to constant and periodic high glucose in vitro.
  
  
  METHODS
  HCAECs were incubated for 72 h continuously either in normal glucose (5.5 mmol/L), constant high glucose (25 mmol/L glucose), periodic high glucose (5.5 and 25 mmol/L glucose alternating every 6 h) or mannitol.
  
  
  METHODS
  Concentrations of interleukin (IL)-6, tumor necrosis factor (TNF)-α and intercellular adhesion molecule (ICAM)-1 in the supernatants of cell culture were measured using ELISA kits. The mRNAs of IL-6, TNF-α and ICAM-1 were evaluated by real-time quantitative PCR.
  
  
  RESULTS
  Periodic high glucose caused a more intense inflammatory response than normal glucose and constant high glucose in HCAECs, with a marked increase in IL-6, TNF-α and ICAM-1 in supernatants of cell culture (P < 0.05). The concentrations of the three pro-inflammatory cytokine mRNAs were higher in cells exposed to periodic high glucose than those exposed to constant high glucose and normal glucose (P < 0.05).
  
  
  CONCLUSIONS
  In cultured HCAECs, periodic high glucose evoked a more intense inflammatory response than constant high glucose.
authors.affiliation: Department of Cardiology, Jinling Hospital, Nanjing 210002, Jiangsu, China. liutingsong@yahoo.com.cn
authors.forename: Tingsong
authors.initials: T
authors.lastname: Liu
authors.forename: Jianbin
authors.initials: J
authors.lastname: Gong
authors.forename: Yitian
authors.initials: Y
authors.lastname: Chen
authors.forename: Shisen
authors.initials: S
authors.lastname: Jiang
mesh_terms: D002478:Cells, Cultured; D003331:Coronary Vessels / Q000166:cytology*; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D005947:Glucose / Q000494:pharmacology*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism*; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*
chemical_list: C573420:ICAM1 protein, human; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D005947:Glucose