title: Co-infection with Chlamydia pneumoniae and Helicobacter pylori results in vascular endothelial dysfunction and enhanced VCAM-1 expression in apoE-knockout mice.
abstract: BACKGROUND
  Upregulation of proinflammatory endothelial cell adhesion molecules and decreased bioactivity of endothelial nitric oxide (NO) are important in the pathogenesis of atherosclerosis. We investigated the effects of co-infection with Chlamydia pneumoniae and Helicobacter pylori on these two events in apoE-KO mice.
  
  
  METHODS
  Thirty-two apoE-KO mice, 8 weeks old, were equally divided into 4 groups. The first 2 groups were infected with either C. pneumoniae or H. pylori, while the 3rd group was infected with both C. pneumoniae and H. pylori. Mice from the 4th group and 4 wild-type mice served as controls. Thoracic and abdominal aortas were harvested after 10 weeks, and staining for vascular cell adhesion molecule-1 (VCAM-1) and intracellular adhesion molecule-1 was analyzed by immunocytochemistry. The endothelial vasomotor responses of thoracic aortas to methacholine were studied in organ chambers in the absence and presence of L-NAME. The plasma levels of nitrate/nitrite were measured.
  
  
  RESULTS
  Staining for VCAM-1 was more intense at the branching sites of aortas from mice with co-infection than in mono-infected or noninfected apoE-KO mice. The relaxation responses to methacholine and the plasma levels of nitrate/nitrite were significantly less in the co-infected group than in the other groups (p < 0.05).
  
  
  CONCLUSIONS
  Co-infection of apoE-KO mice with C. pneumoniae and H. pylori seems to be associated with impaired bioactivity of endothelial NO and increased expression of VCAM-1 at branching sites. The findings may suggest an additive interaction of these pathogens in atherogenesis.
authors.affiliation: Department of Pediatric Cardiology, Lund University Hospital, Lund, Sweden. Petru.Liuba@pedi.lu.se
authors.forename: Petru
authors.initials: P
authors.lastname: Liuba
authors.forename: Erkki
authors.initials: E
authors.lastname: Pesonen
authors.forename: Ilari
authors.initials: I
authors.lastname: Paakkari
authors.forename: Satish
authors.initials: S
authors.lastname: Batra
authors.forename: Leif
authors.initials: L
authors.lastname: Andersen
authors.forename: Anders
authors.initials: A
authors.lastname: Forslid
authors.forename: Seppo
authors.initials: S
authors.lastname: Ylä-Herttuala
authors.forename: Kenneth
authors.initials: K
authors.lastname: Persson
authors.forename: Torkel
authors.initials: T
authors.lastname: Wadström
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Ricardo
authors.initials: R
authors.lastname: Laurini
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis; D001057:Apolipoproteins E / Q000235:genetics*; D002690:Chlamydia Infections / Q000378:metabolism / Q000503:physiopathology*; D016993:Chlamydophila pneumoniae / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D004269:DNA, Bacterial / Q000032:analysis; D004730:Endothelium, Vascular / Q000378:metabolism / Q000503:physiopathology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016481:Helicobacter Infections / Q000378:metabolism / Q000503:physiopathology*; D016480:Helicobacter pylori / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D015151:Immunoblotting; D007150:Immunohistochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009566:Nitrates / Q000097:blood; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009573:Nitrites / Q000097:blood; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism*
chemical_list: D000907:Antibodies, Bacterial; D001057:Apolipoproteins E; D004269:DNA, Bacterial; D004791:Enzyme Inhibitors; D009566:Nitrates; D009573:Nitrites; D019010:Vascular Cell Adhesion Molecule-1; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester