Category: Helicobacter pylori

Helicobacter pylori and endothelial adhesion molecules: DISCUSSION (Part 4)

Although LPS is present in membranes of Gram-negative bacteria such as H pylori and is an important nonprotein proinflammatory molecule, previous studies have shown that H pylori LPS has less biological activity than E coli LPS. We did not examine H pylori LPS directly, but 0.74 EU/mL of E coli LPS did not upregulate adhesion molecules on HUVEC. In addition, final concentrations of LPS in…

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Helicobacter pylori and endothelial adhesion molecules: DISCUSSION (Part 3)

The cagA and vacA genes have been reported to be related to the pathogenecity of H pylori strains, especially with respect to cytokine production from epithelial cells . In the present study, though all strains had both genes, there was no relation between these genes and upregulation of adhesion molecules on HUVEC. In our fractionation study, low-molecular-weight fractions (approximately 7 kDa) showed peak adhesion molecule-inducing…

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Helicobacter pylori and endothelial adhesion molecules: DISCUSSION (Part 2)

However, in the present study, because there is little opportunity for direct contact between bacteria and endothelial cells in gastric mucosa, we used HPE which contains water-soluble components of the membrane or the cytosol. A recent report showed that H pylori alters the barrier properties of the epithelium in vitro. Therefore, HPE, especially low molecular substance in HPE, may permeate into the gastric mucosa and…

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Helicobacter pylori and endothelial adhesion molecules: DISCUSSION (Part 1)

leukocyte-endothelial cell interactions

In the present study, we demonstrated that HPE derived from NCTC11637 induces upregulation of ICAM-1, VCAM-1 and E-selectin on HUVEC. These adhesion molecules play very important roles in leukocyte-endothelial cell interactions which are the initial steps in local inflammation. Inflammatory mediators or cytokines which are increased on tissues by various stimulants activate endothelial cells, and ICAM-1, VCAM-1, E-selectin and other adhesion molecules are expressed on…

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Helicobacter pylori and endothelial adhesion molecules: RESULTS

Surface expression of intercellular adhesion molecule (ICAM)-1

LPS concentrations in the five HPEs ranged from 0.65 EU/mL to 4.16 EU/mL. Final LPS concentrations in medium containing 10% HPE ranged from 0.065 EU/mL to 0.416 EU/mL. All strains were positive for both cagA and vacA genes. Unstimulated HUVEC constitutively expressed ICAM-1 but little VCAM-1 and E-selectin (Figure 1). Coincubation with 20 U/mL of IL-1p (positive control) for 6 h significantly (P<0.05 versus unstimulated)…

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Helicobacter pylori and endothelial adhesion molecules: ELISA (Part 2)

molecule-inducing factor in HPE

Characterization of HPE Gel filtration was used to estimate the molecular weight of the adhesion molecule-inducing factor in HPE from NCTC11637. Freeze-dried extract (10 mg) mixed with 1.5 mL of 150 mM NaCl was eluted through a HiPrep Sephacryl S-100 HR column (Pharmacia Fine Chemicals, USA), with collection of 2 mL fractions. Each fraction (10%) was estimated for adhesion molecule-induction activity. Data were expressed as…

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Helicobacter pylori and endothelial adhesion molecules: ELISA (Part 1)

ELISA was used to assess the binding of mAbs to the endothelial cell monolayers. Confluent HUVEC monolayers prepared in 96-well plates were coincubated with interleukin (IL)-1P (20 U/mL), Escherichia coli lipopolysaccharide (LPS) (0.74 EU/mL, Sigma Chemical Co, USA), or HPE (10%) for 6 h at 37°C in a CO2 incubator. Immediately after pretreatment, the cells were fixed by the addition of 1% paraformaldehyde in PBS…

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Helicobacter pylori and endothelial adhesion molecules: HPE (Part 2)

Endothelial cells

The resulting supernatant, the initial water extract with no preservatives added, was stored at -20°C until needed. Before use, the extract was brought to room temperature and centrifuged at 18,000 rpm (38,700 g) for 20 min, and the pellet was discarded. The supernatant was then passed through a 0.2 micron Acrodisc (Gelman Science, USA) syringe-adapted filter. This procedure removed much of the high molecular weight…

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Helicobacter pylori and endothelial adhesion molecules: HPE (Part 1)

Because adherence between endothelial cells and H pylori, a noninvasive bacterium, cannot occur within gastric mucosa, it is very important to estimate activation of endothelial cells by the stimulation of some substance secreted or released from H pylori. In the present study, we examined whether H pylori water extract (HPE) induces the upregulation of three important adhesion molecules, ICAM-1, VCAM-1 and E-selectin, on cultured human…

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Helicobacter pylori and endothelial adhesion molecules

Helicobacter pylori infection

Helicobacter pylori infection, well known as the cause of chronic active gastritis and peptic ulcer, is associated with gastric mucosal injury. Mucosal infiltration by leukocytes is seen histologically in H pylori infection . Infiltration by leukocytes into gastric mucosa is associated with interactions between leukocytes and endothelial cells. This interaction is the initial important event in inflammation and is mediated by adhesion molecules expressed on…

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