title: Triacylglycerol-rich lipoproteins derived from healthy donors fed different olive oils modulate cytokine secretion and cyclooxygenase-2 expression in macrophages: the potential role of oleanolic acid.
abstract: OBJECTIVE
  Current evidence suggests that consumption of virgin olive oil (VOO) helps to protect against the development of atherosclerosis and that minor components such as oleanolic acid contribute to this effect. In this study, the effects of triacylglycerol-rich lipoproteins (TRLs) derived from olive oil on inflammatory processes in macrophages and how they are modulated by oleanolic acid was investigated.
  
  
  METHODS
  TRLs isolated from healthy volunteers 2 and 4 h after a test meal containing VOO, pomace olive oil (POO) (the second pressing of olive oil, enriched in minor components) or POO enriched with oleanolic acid (OPOO) were incubated with macrophages derived from the human monocyte cell line, THP-1.
  
  
  RESULTS
  All types of TRLs caused a decrease of about 50% in the secretion of monocyte chemoattractant protein-1 (MCP-1) by the cells. Interleukin (IL)-6 secretion was also significantly decreased by 2 and 4 h VOO TRLs and by 4 h OPOO TRLs. In contrast, increased IL-1β secretion was observed with all 2 h TRL types, and increased tumour necrosis factor-α (TNF-α) production with 2 h VOO and POO, but not OPOO, TRLs. TRLs isolated after 4 h, however, had no significant effects on TNF-α secretion and increased IL-1β secretion only when they were derived from VOO. Cyclooxygenase-2 (COX-2) mRNA expression was strongly down-regulated by all types of TRLs, but protein expression was significantly depressed only by 4 h OPOO TRLs.
  
  
  CONCLUSIONS
  These findings demonstrate that TRLs derived from olive oil influence inflammatory processes in macrophages and suggest that oleanolic acid may have beneficial effects.
authors.affiliation: Department of Veterinary Basic Sciences, The Royal Veterinary College, Royal College St, London, NW1 0TU, UK.
authors.forename: V S
authors.initials: VS
authors.lastname: Graham
authors.forename: C
authors.initials: C
authors.lastname: Lawson
authors.forename: C P D
authors.initials: CP
authors.lastname: Wheeler-Jones
authors.forename: J S
authors.initials: JS
authors.lastname: Perona
authors.forename: V
authors.initials: V
authors.lastname: Ruiz-Gutierrez
authors.forename: K M
authors.initials: KM
authors.lastname: Botham
mesh_terms: D000328:Adult; D002460:Cell Line; D018932:Chemokine CCL2 / Q000187:drug effects / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation; D006801:Humans; D053583:Interleukin-1beta / Q000187:drug effects / Q000378:metabolism*; D015850:Interleukin-6 / Q000378:metabolism; D008074:Lipoproteins / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism; D008297:Male; D009828:Oleanolic Acid / Q000008:administration & dosage; D000069463:Olive Oil; D010938:Plant Oils / Q000008:administration & dosage*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014280:Triglycerides / Q000008:administration & dosage*; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects / Q000378:metabolism; D055815:Young Adult
chemical_list: C111835:CCL2 protein, human; D018932:Chemokine CCL2; D053583:Interleukin-1beta; D015850:Interleukin-6; D008074:Lipoproteins; D000069463:Olive Oil; D010938:Plant Oils; D012333:RNA, Messenger; D014280:Triglycerides; D014409:Tumor Necrosis Factor-alpha; D009828:Oleanolic Acid; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human