Mechanisms involved in Helicobacter pylori-induced inflammation.
BACKGROUND
Helicobacter pylori infection is associated with mucosal inflammation. The aims of the present study were to assess whether a water extract of H. pylori promotes neutrophil (polymorphonuclear leukocyte [PMN]) adherence to endothelial cells and define the molecular basis of this adhesive interaction.


METHODS
Intravital microscopy was used to study leukocyte adhesive interactions in rat mesenteric venules in situ. PMN-endothelial cell adhesive interactions were studied in vitro using human PMNs and monolayers of human umbilical vein endothelial cells (HUVEC).


RESULTS
In vivo, superfusion of rat mesentery with the H. pylori extract increased leukocyte adhesion and emigration in venules. In vitro, adhesion of human PMNs to HUVEC was increased by the H. pylori extract in a concentration-dependent manner. Pretreatment of HUVEC alone with H. pylori extract had no effect on PMN adherence, whereas pretreatment of PMN alone significantly increased their adherence to HUVEC. The extract-induced adhesion was significantly diminished by monoclonal antibodies (MAb) directed against either CD11a, CD11b, or CD18 on neutrophils, and by MAbs against intercellular adhesion molecule-1 (ICAM-1), but not E- or P-selectin, on endothelial cells.


CONCLUSIONS
These studies suggest that products of H. pylori elicit gastrointestinal inflammation by promoting PMN adhesion to endothelial cells via CD11a/CD18- and CD11b/CD18-dependent interactions with ICAM-1.
Yoshida
N
N
Department of Physiology, Louisiana State University Medical Center, Shreveport.
Granger
D N
DN
Evans
D J
DJ
Evans
D G
DG
Graham
D Y
DY
Anderson
D C
DC
Wolf
R E
RE
Kvietys
P R
PR
D000818:Animals; D015703:Antigens, CD / Q000502:physiology; D018845:CD11 Antigens; D018821:CD18 Antigens; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000502:physiology; D002450:Cell Communication; D002478:Cells, Cultured; D004382:Duodenitis / Q000209:etiology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology; D005756:Gastritis / Q000209:etiology*; D016480:Helicobacter pylori / Q000472:pathogenicity*; D018799:Intercellular Adhesion Molecule-1; D008297:Male; D009504:Neutrophils / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D015703:Antigens, CD; D018845:CD11 Antigens; D018821:CD18 Antigens; D015815:Cell Adhesion Molecules; D018799:Intercellular Adhesion Molecule-1