Stimulation of adhesion molecule expression by Helicobacter pylori and increased neutrophil adhesion to human umbilical vein endothelial cells

The relation between Helicobactor pylori gastrointestinal tract infection and central serous chorioretinopathy among patients in Al-Diwaniya province

PURPOSE:

Central serous chorioretinopathy (CSR) is a serous detachment of the central retina. This condition usually affects young males. Its pathogenesis is not fully understood. Helicobactor pylori is the most prevalent stomach and gastrointestinal tract (GIT) infection worldwide, and a possible correlation between these two conditions was examined in this study.

METHODS:

Sixty-two patients with CSR (fifty-five males and seven females) were included in this study. All patients were examined by a senior ophthalmologist and fluorescein angiography was performed for each patient to confirm CSR, which has specific ophthalmic findings. It was found to be the first attack of CSR in 49 patients with the help of history and optical coherence tomography and an Amsler grid test, while in 13 patients it was shown to be recurrent disease. Diagnosis of H. pylori was done using the urea breath test at the GIT center in Diwaniya Teaching Hospital, Iraq. The control group contained 162 patients attending the GIT Department at Diwaniya Teaching Hospital with 79 patients with a positive H. pylori test and normal comprehensive eye examinations. Patients with any other ophthalmic diseases were excluded from the study.

RESULTS:

The rate of infection was significantly higher in patients than in control group (47/75.8% vs. 79/48.8%; P < 0.001). The odds ratio was 3.29 with 95% confidence interval of 1.71–6.36; therefore, patients with CSR are 3.29 times more susceptible to H. pylori infections than control subjects.

CONCLUSION:

A statistically significant relationship between the presence of H. pylori infections with CSR development among young patients was shown. More multi-center studies are needed to confirm this relationship.

Both diet and Helicobacter pylori infection contribute to atherosclerosis in pre- and postmenopausal cynomolgus monkeys

A number of viruses and bacterial species have been implicated as contributors to atherosclerosis, potentially providing novel pathways for prevention. Epidemiological studies examining the association between Helicobacter pylori and cardiovascular disease have yielded variable results and no studies have been conducted in nonhuman primates. In this investigation, we examined the relationship between H. pylori infection and atherosclerosis development in socially housed, pre- and postmenopausal cynomolgus macaques consuming human-like diets. Ninety-four premenopausal cynomolgus monkeys (Macaca fascicularis) were fed for 36 months an atherogenic diet deriving its protein from either casein lactalbumin(CL) or high isoflavone soy (SOY). Animals were then ovariectomized and fed either the same or the alternate diet for an additional 36 months. Iliac artery biopsies were obtained at the time of ovariectomy and iliac and coronary artery sections were examined at the end of the study. Evidence of H. pylori infection was found in 64% of the monkeys and 46% of animals had live H. pylori within coronary atheromas as determined by mRNA-specific in situ hybridization. There was a significant linear relationship between the densities of gastric and atheroma organisms. Helicobactor pylori infection correlated with increased intimal plaque area and thickness at both the premenopausal and postmenopausal time points and regardless of diet (p< 0.01), although animals consuming the SOY diet throughout had the least amount of atherosclerosis. Additionally, plasma lipid profiles, intimal collagen accumulation, ICAM-1, and plaque macrophage densities were adversely affected by H. pylori infection among animals consuming the CL diet, while the SOY diet had the opposite effect. Plaque measurements were more highly associated with the densities of cagA-positive H. pylori within coronary atheromas than with the densities of gastric organisms, whereas plasma lipid changes were associated with H. pylori infection, but not cagA status. This study provides strong evidence that live H. pylori infects atheromas, exacerbates atherosclerotic plaque development, and alters plasma lipid profiles independently of diet or hormonal status. Finally, socially subordinate animals relative to their dominant counterparts had a greater prevalence of H. pylori, suggesting a stress effect. The results indicate that early H. pylori eradication could prevent or delay development of cardiovascular disease.

Helicobacter pylori urease induces pro-inflammatory effects and differentiation of human endothelial cells: Cellular and molecular mechanism

BACKGROUND

Helicobacter pylori urease (HPU) is a key virulence factor that enables bacteria to colonize and survive in the stomach. We early demonstrated that HPU, independent of its catalytic activity, induced inflammatory and angiogenic responses in vivo and directly activated human neutrophils to produce reactive oxygen species (ROS). We have investigated the effects of HPU on endothelial cells, focusing on the signaling mechanism involved.

METHODS

Monolayers of human microvascular endothelial cells (HMEC-1) were stimulated with HPU (up to 10 nmol/L): Paracellular permeability was accessed through dextran-FITC passage. NO and ROS production was evaluated using intracellular probes. Proteins or mRNA expressions were detected by Western blotting and fluorescence microscopy or qPCR assays, respectively.

RESULTS

Treatment with HPU enhanced paracellular permeability of HMEC-1, preceded by VE-cadherin phosphorylation and its dissociation from cell-cell junctions. This caused profound alterations in actin cytoskeleton dynamics and focal adhesion kinase (FAK) phosphorylation. HPU triggered ROS and nitric oxide (NO) production by endothelial cells. Increased intracellular ROS resulted in nuclear factor kappa B (NF-κB) activation and upregulated expression of cyclooxygenase-2 (COX-2), hemeoxygenase-1 (HO-1), interleukin-1β (IL-1β), and intercellular adhesion molecule-1 (ICAM-1). Higher ICAM-1 and E-selectin expression was associated with increased neutrophil adhesion on HPU-stimulated HMEC monolayers. The effects of HPU on endothelial cells were dependent on ROS production and lipoxygenase pathway activation, being inhibited by esculetin. Additionally, HPU improved vascular endothelial growth factor receptor 2 (VEGFR-2) expression.

CONCLUSION

The data suggest that the pro-inflammatory properties of HPU drive endothelial cell to a ROS-dependent program of differentiation that contributes to the progression of H pylori infection.

Helicobacter pylori as a risk factor for central serous chorioretinopathy: Literature review

Helicobacter pylori (H. pylori), a Gram-negative bacterium, is one of the most frequent causes of gastrointestinal infections worldwide. It has been associated as a pathogen for the human body with many systemic diseases, including different eye diseases. We will focus on a specific eye disease called idiopathic central serous chorioretinopathy (ICSCR). This disease is characterized by a serous detachment of the neurosensory retina in the macular region, which affects the vision to different degrees. Currently, the pathophysiology of ICSCR is not clear and there is no effective treatment. However, several potential risk factors have been elucidated. One of the factors that has more frequently been associated with ICSCR is stress. As H. pylori was identified as a possible etiological factor for occlusive arterial diseases in young people who were particularly stressed, it was thought that H. pylori might also be present in ICSCR. Therefore, some physicians started to test its presence in patents with ICSCR. If H. pylori happened to be associated with ICSCR, the treatment of gastrointestinal infection could also improve visual symptoms and help to remediate this eye disease. Although H. pylori is highly prevalent in the general population, a true correlation seems to exist. We present a review on the relationship between ICSCR and H. pylori.

Curcumin suppresses gastric NF-κB activation and macromolecular leakage in Helicobacter pylori-infected rats

AIM: To investigate whether curcumin could attenuate nuclear factor (NF)-κB p65 expression and macromolecular leakage in the gastric mucosa of Helicobacter pylori (H. pylori)-infected rats.

METHODS: Twenty-five male Sprague-Dawley rats were equally divided into five groups: control rats (Control), control rats supplemented with 600 mg/kg curcumin, H. pylori-infected rats (Hp), H. pylori-infected rats supplemented with 200 mg/kg curcumin (Hp + curI), and H. pylori-infected rats supplemented with 600 mg/kg curcumin (Hp + curII). In H. pylori-infected groups, rats were inoculated with H. pylori suspension twice a day at an interval of 4 h for 3 d. Two weeks later, 200 or 600 mg/kg curcumin was given once daily to curcumin-supplemented groups for 7 d. On the day of the experiment, macromolecular leakage in gastric mucosa was examined by intravital fluorescence microscopy. The stomach tissue was removed to examine NF-κB p65 expression in gastric epithelial cells by immunohistochemistry.

RESULTS: The expression of NF-κB p65 in gastric epithelial cells and the macromolecular leakage from gastric mucosal microcirculation significantly increased in the Hp group compared with the Control group. The percentages of NF-κB p65 immunoreactive cells in Control and Hp groups were 10.72% ± 2.10% vs 16.02% ± 2.98%, P = 0.004, respectively. The percentages of macromolecular leakage in Control and Hp groups were 10.69% ± 1.43% vs 15.41% ± 2.83%, P = 0.001, respectively. Curcumin supplementation in Hp + curI and Hp + curII groups significantly decreased NF-κB p65 immunoreactive cells and macromolecular leakage compared with results in the Hp group. The percentages of NF-κB p65 immunoreactive cells in Hp + curI and Hp + curII groups were 11.79% ± 2.13% (P = 0.017) and 11.42% ± 1.68% (P = 0.010), respectively. The percentages of macromolecular leakage in Hp + curI and Hp + curII groups were 12.32% ± 2.13% (P = 0.025) and 12.14% ± 1.86% (P = 0.018), respectively.

CONCLUSION: H. pylori-induced gastric inflammation in rats is associated with increased NF-κB activation and macromolecular leakage which can be reduced by curcumin supplementation.

Simulation of intra-amniotic infection and the fetal inflammatory response in a novel ex-vivo human umbilical cord perfusion model

OBJECTIVE

We aimed to design and test an ex-vivo human umbilical cord (HUC) perfusion model simulating a fetal inflammatory response (FIR) during intra-amniotic infection.

STUDY DESIGN

A 2-chamber model was designed to accommodate 2 pieces of umbilical cord. Cord perfusion was performed with placental blood. Intra-amniotic exposure to infectious organisms was simulated by adding lipopolysaccharide to the artificial amniotic fluid (AAF) compartment. As a measure of inflammatory response, we used interleukin 8 (IL-8) concentration in AAF and plasma by enzyme-linked immunosorbent assay (ELISA). Wilcoxon signed rank test was used for statistical analysis.

RESULTS

We established a stable physiological setup. Results revealed significantly elevated plasma IL-8 concentrations (n = 6, P < .05) in the blood compartment of umbilical cords exposed to lipopolysaccharide. Concentrations within AAF were not significantly elevated (n = 6, P = .3095).

CONCLUSION

Simulation of a FIR in an ex-vivo model of HUC perfusion under physiological conditions is possible. Further work is necessary to establish histological funisitis.

P-selectin-dependent platelet aggregation and apoptosis may explain the decrease in platelet count during Helicobacter pylori infection

P-selectin expression has been shown in Helicobacter pylori-infected persons, an infection that has been clinically associated with platelet-related diseases, such as idiopathic thrombocytopenic purpura. However, the role of P-selectin expression during H pylori infection remains unclear. In this study, we hypothesized that P-selectin expression was associated with platelet aggregation during H pylori infection. Using flow cytometry, we examined the levels of adhesion between H pylori and platelets as well as the levels of P-selectin expression and platelet phosphatidylserine (PS) expression during H pylori infection. Significantly high levels of adhesion between pro-aggregatory bacteria and platelets were observed. We identified that H pylori IgG is required for bacteria to induce P-selectin expression and that a significant release of P-selectin is essential for H pylori to induce aggregation. In addition, cellular apoptotic signs, such as membrane blebbing, were observed in platelet aggregates. PS expression was also detected in platelets during infection with both pro-aggrogatory and nonaggregatory strains of H pylori. These results suggest that the decrease in platelet counts seen during H pylori infection is the result of P-selection-dependent platelet aggregation and PS expression induced by the bacteria.

Helicobacter pylori and antrum erosion-specific gene expression patterns: the discriminative role of CXCL13 and VCAM1 transcripts

BACKGROUND AND AIMS

Chronic Helicobacter pylori infection affects approximately half of the world, leads to chronic gastritis and peptic ulceration, and is linked to gastric carcinoma. Our aims were to compare the gene expression profile (GEP) of H. pylori-positive and H. pylori-negative gastric erosions and adjacent mucosa to explain the possible role and response to H. pylori infection and to get erosion-related mRNA expression patterns.

METHODS

Total RNA was extracted, amplified, and biotinylated from gastric biopsies of patients with H. pylori-positive and H. pylori-negative antrum erosions (ER) (8/8) and adjacent macroscopically normal mucosae (8/8). The GEP was evaluated using HGU133plus2.0 microarrays. Two independent normalizations (MAS5.0, RMA), PAM feature selection, hierarchical cluster analysis, and discriminant analysis were done. The expression of 14 genes was also measured by real-time-polymerase chain reaction. VCAM-1 and CXCL13 immunohistochemistry (IHC) was done.

RESULTS

In H. pylori infection, significant overexpression of MHC class II antigen-presenting genes, interleukin-7 receptor, ubiquitin-D, CXCR4, lactoferrin immune response-related genes, CXCL-2 and -13, CCL18 chemokine ligand, and VCAM-1 genes were established. In erosive gastritis, increased proliferation (MET) and transport (UCP2, SCFD1, KPNA4) were found, while genes associated with adhesion (SIGLEC11), transcription regulation (ESRRG), and electron and ion transport (ACADM, CLIC6) were down-regulated. Discriminant analysis successfully classified all samples into four groups (HP+ER-, HP+ER+, HP-ER+, HP-ER-) using a reduced gene set (20). Significant overexpression of VCAM-1 and CXC13 protein was detected by IHC in HP+ samples (p < .05).

CONCLUSIONS

Whole genomic microarray analysis yielded new H. pylori infection and erosion-related gene expression changes. Discriminative genes can be used in mRNA-based diagnostic classification of gastric biopsies.

Inhibition of interleukin-8 production in human endothelial cells by Staphylococcus aureus supernatant

Recent reports have shown that Staphylococcus aureus infection increases the expression of cytokines and cell adhesion molecules in endothelial cells and enhances leucocyte migration, thereby resulting in bacterial elimination. In this study, we analysed the production of the chemokine interleukin (IL)-8 in human umbilical vein endothelial cells (HUVEC) infected with several S. aureus strains by using reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. We found that the avirulent strains (00-51 and 00-62) increased IL-8 production but the virulent strains (A17 and A151) decreased it at both the mRNA and protein levels. We considered that the inhibition of IL-8 production depended on certain inhibitory factor(s) secreted by bacteria. This was because S. aureus also abolished IL-8 expression in HUVEC treated with cytochalasin D, and the addition of culture supernatants of strains A17 and A151 decreased IL-8 production in HUVEC. This factor(s) in the bacterial culture supernatant inhibited both basal and tumour necrosis factor (TNF)-alpha-induced IL-8 production. In contrast, no inhibitory effect was observed on monocyte chemotactic protein-1 (MCP-1) production. These results indicate that S. aureus can down-regulate IL-8 release in endothelial cells through the secretion of inhibitory factor(s), and this may result in decreased neutrophil recruitment, thus interfering with the host immune response to bacterial infection.

Soluble adhesion molecules ICAM-1, VCAM-1, P-selectin in children with Helicobacter pylori infection

AIM: To assess the sICAM-1, sVCAM-1, and sP-selectin levels in children with Helicobacter pylori (H pylori) infection and to evaluate their significance for the morphological changes found in gastric mucosa.

METHODS: The study included 106 children: 59 children (55.7%) with chronic gastritis and positive IgG against H pylori, 29 children (27.3%) after previous H pylori infection without the bacterium colonization but with positive IgG against H pylori, and 18 children (17%) with functional disorders of the gastrointestinal system but with normal IgG against H pylori. Endoscopic and histopathological evaluation of gastric mucosa was performed based on the Sydney System classification. The evaluation of sP-selectin, sICAM-1, sVCAM-1 levels in the sera of children was carried out using ELISA test.

RESULTS: The assessment of gastritis activity degrees indicated statistically significant values in the antrum and corpus (P<0.001) of children examined. Serum sVCAM-1 levels were higher in group with gastritis due to H pylori infection than in group without infection and differed statistically (P<0.05). Serum sVCAM-1 levels proved to be the highest among other adhesive molecules in infected children and decreased after eradication of H pylori. Serum sICAM-1 levels were similar in all examined groups. Serum sP-selectin levels were similar in children with and without H pylori infection.

CONCLUSION: Assessment of adhesive molecules (sP-selectin, sICAM-1, sVCAM-1) in the sera of children with active H pylori infection can show the participation of sVCAM-1 in the pathogenesis of gastric mucosal inflammation. sP-selectin and sICAM-1 concentrations in the sera of children with H pylori infection after eradication cannot reveal any significant differences as compared to healthy children.

Association of Helicobacter pylori with central serous chorioretinopathy: hypotheses regarding pathogenesis

Central serous chorioretinopathy (CSC) is a serous macular detachment that usually affects young people and leads fortunately to a spontaneous resolution and a good visual prognosis in most patients. Nevertheless, although in a small percentage of subjects only, it may also develop a chronic or progressive disease with widespread decompensation of the retinal pigment epithelium (RPE) and severe vision loss. The aetiopathogenesis of the disease is still not completely understood and no effective treatment is available at this time. However, an interesting association has been recently highlighted between CSC and the Helicobacter pylori infection. In particular, in a first case report recurrences of the disease were always associated with HP-positivity whereas improvements of both retinal findings and visual acuity were significantly correlated with a successful eradication of the bacterium using the conventional antimicrobial triple-therapy. In a second study, the prevalence of HP infection was found to be significantly higher in CSC-affected subjects compared to age- and sex-matched controls from the same country. Much speculation surrounds the role potentially played by HP in determining CSC. In particular, CSC seems not to be more a merely RPE disease but the final result of a general involvement of the choroidal microcirculation. In fact, several vascular abnormalities, such as localized vasoconstriction and impaired fibrinolysis, have been demonstrated during CSC whose "end-points" might be a focal occlusion of the choriocapillaries with decreased foveal choroidal blood flow, secondary RPE defects and serous macular detachment. Moreover, a HP-dependent immune mechanism, based on a "molecular mimicry" between pathogenic antigens expressed on the bacterium and homologous host proteins (e.g., those of the endothelial vascular wall), might also be involved in the pathophysiology of CSC. In this case, a genetically determined susceptibility of the subject could be an important and limiting factor. Although further multicenter, randomized, case-control trials are necessary to confirm the role potentially played by the HP infection in the pathogenesis of CSC, if this hypothesis would be confirmed in the near future, a novel antimicrobial approach to the disease might be possible waiting for a successful vaccine therapy that will surely stimulate the scientific interest of many authors.

Adrenomedullin enhances angiogenic potency of bone marrow transplantation in a rat model of hindlimb ischemia

BACKGROUND

Previous studies have shown that adrenomedullin (AM) inhibits vascular endothelial cell apoptosis and induces angiogenesis. We investigated whether AM enhances bone marrow cell-induced angiogenesis.

METHODS AND RESULTS

Immediately after hindlimb ischemia was created, rats were randomized to receive AM infusion plus bone marrow-derived mononuclear cell (MNC) transplantation (AM+MNC group), AM infusion alone (AM group), MNC transplantation alone (MNC group), or vehicle infusion (control group). The laser Doppler perfusion index was significantly higher in the AM and MNC groups than in the control group (0.74+/-0.11 and 0.69+/-0.07 versus 0.59+/-0.07, respectively, P<0.01), which suggests the angiogenic potency of AM and MNC. Importantly, improvement in blood perfusion was marked in the AM+MNC group (0.84+/-0.08). Capillary density was highest in the AM+MNC group, followed by the AM and MNC groups. In vitro, AM inhibited MNC apoptosis, promoted MNC adhesiveness to a human umbilical vein endothelial cell monolayer, and increased the number of MNC-derived endothelial progenitor cells. In vivo, AM administration not only enhanced the differentiation of MNC into endothelial cells but also produced mature vessels that included smooth muscle cells.

CONCLUSIONS

A combination of AM infusion and MNC transplantation caused significantly greater improvement in hindlimb ischemia than MNC transplantation alone. This effect may be mediated in part by the angiogenic potency of AM itself and the beneficial effects of AM on the survival, adhesion, and differentiation of transplanted MNCs.

Differential roles of interleukin-1beta and interleukin-8 in neutrophil transendothelial migration in patients with Helicobacter pylori infection

BACKGROUND

Little information is currently available on the contribution of locally generated inflammatory and chemotactic cytokines to endothelial cell activation and subsequent neutrophil transendothelial migration in patients with Helicobacter pylori (H. pylori)-associated gastritis.

METHODS

The contents of interleukin (IL)-1beta and IL-8 in the organ culture supernatants of antral mucosal tissues were measured with an enzyme-linked immunosorbent assay. The effects of the endogenous IL-1beta and IL-8 in mucosal tissues on neutrophil adherence and transendothelial migration were investigated using an experimental model of human umbilical vein endothelial cells (HUVEC).

RESULTS

The contents of IL-1beta and IL-8 in organ cultures of antral mucosal tissues were significantly higher in patients with H. pylori infection than in those without infection. The organ culture supernatants from H. pylori-positive patients induced the expression of intercellular adhesion molecule-1 mRNA in HUVEC with increased binding of neutrophils, and these stimulatory effects were inhibited when HUVEC were pretreated with a nuclear factor-kappaB inhibitor, MG-132. Moreover, neutrophil adherence to HUVEC induced by the supernatants decreased after preincubation with neutralizing anti-IL-1beta antibody. As compared with the supernatants from H. pylori-negative patients, the samples from H. pylori-positive patients exhibited a significantly higher chemotactic activity for neutrophils, which was inhibited almost completely by preincubation of the supernatants with anti-IL-8 antibody.

CONCLUSIONS

Locally generated IL-1beta and IL-8 could coordinate with each other during the process of neutrophil infiltration into the gastric mucosa in patients with H. pylori infection.