Helicobacter pylori-induced microvascular protein leakage in rats: role of neutrophils, mast cells, and platelets.
OBJECTIVE
Previous studies indicate that a water extract of Helicobacter pylori (HPE) can promote neutrophil-endothelial cell interactions in vivo and in vitro. The objectives of this study were to assess whether HPE alters the rate of albumin leakage in rat mesenteric venules and identify the factors that mediate the HPE-induced microvascular dysfunction.


METHODS
Intravital microscopy was used to continuously monitor leukocyte adherence and emigration and albumin leakage in rat mesenteric venules during superfusion with HPE.


RESULTS
HPE increased leukocyte adherence and emigration and microvascular albumin leakage. The enhanced albumin leak could be subdivided into two components: an early (within 10 minutes) and a later (within 30 minutes) phase. HPE also elicited perivenular mast cell degranulation and the formation of platelet-leukocyte aggregates within post-capillary venules. The HPE-induced early phase of albumin leakage was attenuated by pretreatment with a mast cell stabilizer. The HPE-induced late phase of albumin leakage was reduced by monoclonal antibodies directed against either CD11b/CD18 or intercellular adhesion molecule 1. A monoclonal antibody against P-selectin also inhibited the HPE-induced platelet-leukocyte aggregation and reduced the later phase of albumin leak.


CONCLUSIONS
HPE-induced microvascular dysfunction appears to be a consequence of interstitial and intravascular cell-cell interactions.
Department of Physiology, Louisiana State University Medical Center, Shreveport.
I
I
Kurose
D N
DN
Granger
D J
DJ
Evans
D G
DG
Evans
D Y
DY
Graham
M
M
Miyasaka
D C
DC
Anderson
R E
RE
Wolf
G
G
Cepinskas
P R
PR
Kvietys
D000418:Albumins / Q000493:pharmacokinetics*; D000818:Animals; D001792:Blood Platelets / Q000166:cytology / Q000502:physiology*; D002196:Capillaries / Q000166:cytology* / Q000502:physiology; D002199:Capillary Permeability / Q000502:physiology*; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D004730:Endothelium, Vascular / Q000166:cytology* / Q000502:physiology; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D016481:Helicobacter Infections / Q000097:blood / Q000378:metabolism / Q000503:physiopathology; D016480:Helicobacter pylori / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D008407:Mast Cells / Q000166:cytology / Q000502:physiology*; D009504:Neutrophils / Q000166:cytology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014699:Venules / Q000166:cytology / Q000502:physiology
D000418:Albumins