Rescue of Helicobacter pylori-induced cytotoxicity by red ginseng

Helicobacter pylori has been known to provoke gastric inflammation, ulceration, and DNA damage, based on which WHO defined H. pylori as a class I carcinogen. Although ginseng, the root of Panax ginseng C.A. Meyer, has been reported to possess antiadhesion or antimicrobial activity against H. pylori, in this study, we examined the protective effect of red ginseng extracts (RGE) against H. pylori-induced cytotoxicity and DNA damage. RGE significantly attenuated both H. pylori-induced DNA damage assessed by comet assay and apoptosis measured by DNA fragmentation. Inactivation of ERK1/2 signaling and attenuation of caspase-3 activation and PARP cleavage were revealed with RGE against H. pylori infection. RGE decreased H. pylori-stimulated IL-8 gene expression, which resulted from the transcriptional regression of NF-kappaB. In conclusion, RGE showed significant gastroprotective effects against H. pylori-associated gastric mucosal cell damage, suggesting that red ginseng could be used as a medicinal phytonutrient against H. pylori infection.

The secreted peptidyl prolyl cis,trans-isomerase HP0175 of Helicobacter pylori induces apoptosis of gastric epithelial cells in a TLR4- and apoptosis signal-regulating kinase 1-dependent manner

Apoptosis contributes to the pathology of gastric epithelial cell damage that characterizes Helicobacter pylori infection. The secreted peptidyl prolyl cis, trans-isomerase of H. pylori, HP0175 executed apoptosis of the gastric epithelial cell line AGS in a dose- and time-dependent manner. The effect of HP0175 was confirmed by generating an isogenic mutant of H. pylori disrupted in the HP0175 gene. The apoptosis-inducing ability of this mutant was impaired compared with that of the wild type. The effect of HP0175 was mediated through TLR4. Preincubation of the gastric epithelial cell line AGS with anti-TLR4 mAb inhibited apoptosis induced by HP0175. Downstream of TLR4, apoptosis signal-regulating kinase 1 activated MAPK p38, leading to the caspase 8-dependent cleavage of Bid, its translocation to the mitochondria, mitochondrial pore formation, cytochrome c release, and activation of caspases 9 and 3. We show for the first time that a secreted bacterial Ag with peptidyl prolyl cis,trans-isomerase activity signals through TLR4, and that this Ag executes gastric epithelial cell apoptosis through a signaling pathway in which TLR4 and apoptosis signal-regulating kinase 1 are central players.

Effects of excretory/secretory products of Haemonchus contortus on cell vacuolation

Excretory/secretory (ES) products of the gastric nematode, Haemonchus contortus, have been implicated in the inhibition of gastric acid secretion which follows infection. Parietal cell vacuolation has been observed in abomasal sections from parasitised sheep, and ES prepared in vitro has been reported to cause vacuolation and to increase neutral red (NR) uptake in epithelial cell cultures. We have used the latter approach to examine, at the cellular level, the effects of ES prepared from L3 and adult nematodes. Both NR uptake and cellular vacuolation were increased following exposure to larval or adult ES products. ES preparations from adult worms induced more extensive vacuolation then those from L3 worms and, as with VacA treatment, adherent cells remained viable despite high levels of vacuolation. Whereas VacA-induced vacuolation resulted in NR uptake predominantly localised in vacuoles, this appeared not to be the case with ES-induced vacuolation, suggesting that different mechanisms might be involved. Both ES and VacA exposure was associated with an increased rate of cell detachment.

Molecular markers in Helicobacter pylori-associated gastric carcinogenesis

Helicobacter pylori infection is a known risk factor of gastric carcino-genesis. This article presents early molecular alterations associated with H. pylori chronic gastritis and advances in the molecular characterization of preneoplastic intestinal metaplasia (IM) and premalignant gastric mucosal lesions. H. pylori infection induces changes in gene expression, genomic instability and accumulation of gene mutations in the stomach epithelium. Mutations, including LOH and microsatellite instability, and gene hypermethylation are seen not only in gastric cancer, but are already detectable in IM and gastric dysplasia/adenoma. Recent reports using microarray expression analysis identified several gastric epithelial genes that are regulated by H. pylori. Among the many genes showing altered epithelial expression in response to H. pylori, some might be useful as markers to assess gastric cancer risk. Profiles of mutagenesis and gene expression in IM and dysplasia/adenoma have been characterized and represent potential markers of preneoplastic and premalignant lesions during gastric carcinogenesis.

Aspiration of gastric contents: association with prehospital intubation

We prospectively compared the incidence of pulmonary aspiration of gastric contents between patients endotracheally intubated in the prehospital (PH) setting and those intubated in the emergency department (ED). Tracheal aspirates were collected using a standard Leukens trap from all patients as soon as possible after endotracheal intubation. Tracheal aspirates were then tested for the presence of pepsin, a sensitive and specific marker of gastric contents, using a fibrinogen digestion technique. Over 8 months, 168 patients were enrolled. The pepsin assay was positive in 10 of 20 (50%) patients intubated in the PH group, as opposed to 33 of 148 (22%) of those intubated in the ED (chi2 P=.008; odds ratio, 3.5; 95% CI, 1.34-9.08). Patients endotracheally intubated in the PH setting are more likely to have aspirated gastric contents than those intubated in the ED.

Detection of pepsin in tracheal secretions after forced small-volume aspirations of gastric juice

BACKGROUND

Detecting small-volume aspirations of gastric contents is an important but difficult task. A potentially useful method for this purpose is assaying tracheal secretions for pepsin, an expected constituent of gastric juice.

METHODS

A 2-group experimental design was used. The primary subjects were 161 experimental and 21 control New Zealand white rabbits; 161 acutely ill humans provided the gastric juice used in the project. The animals were anesthetized before being intubated and mechanically ventilated. Three separate boluses of human gastric juice mixed with dye-stained enteral formula were instilled into the experimental animals' tracheas; the 21 control animals received only 0.9% sodium chloride solution. At the beginning of each experiment, 0.4 mL/kg of the substance was infused over a 30-minute period; the infusion was then stopped and 90 minutes were allowed to elapse before endotracheal suctioning was performed. This procedure was repeated at hour 2 and hour 4. After completion of the multiple aspiration portion of the study, 23 additional animals were subjected to a single aspiration of 0.4 mL/kg of a mixture of human gastric juice and dye-stained enteral formula; secretions were obtained at 2 hours, 4 hours, and 6 hours. An immunoassay was used to test for pepsin in all of the tracheal secretions.

RESULTS

In the 3-aspiration group, pepsin was found in all of the secretions from 92.5% (149/161) of the experimental animals; in contrast, no pepsin was found in any of the secretions from the 20 control animals. In the single-aspiration group, pepsin was found in all of the tracheal secretions from the 23 animals at 2 hours and 4 hours and 21 of the 23 animals at 6 hours.

CONCLUSIONS

The immunoassay used in this animal model study was able to detect pepsin in >90% of the experimental animals' tracheal secretions after multiple or single forced aspirations of gastric juice. The extent to which pepsin can be detected in the tracheal secretions of acutely ill tube-fed humans requires investigation, as does the extent to which clinical outcomes are affected by pepsin-positive tracheal secretions.

Macrophage migration inhibitory factor stimulated by Helicobacter pylori increases proliferation of gastric epithelial cells

AIM

Helicobacter pylori (H pylori) is associated with increased gastric inflammatory and epithelial expression of macrophage migration inhibitory factor (MIF) and gastric epithelial cell proliferation. This study aimed at determining whether H pylori directly stimulates release of MIF in monocytes, whether the cag pathogenicity island (PAI) is involved for this function, and whether MIF stimulated by H pylori increases gastric epithelial cell proliferation in vitro.

METHODS

A cytotoxic wild-type H pylori strain (TN2), its three isogenic mutants (TN2Deltacag, TN2DeltacagA and TN2DeltacagE) were co-cultured with cells of a human monocyte cell line, THP-1, for 24 h at different organism/cell ratios. MIF in the supernatants was measured by an ELISA. Cells of a human gastric cancer cell line, MKN45, were then co-cultured with the supernatants, with and without monoclonal anti-MIF antibody for 24 h. The cells were further incubated for 12 h after addition of 3H-thymidine, and the levels of incorporation of 3H-thymidine were measured with a liquid scintillation counter.

RESULTS

The wild-type strain and the isogenic mutants, TN2DeltacagA and TN2 DeltacagE, increased MIF release at organism/cell ratios of 200/1 and 400/1, but not at the ratios of 50/1 and 100/1. However, the mutant TN2delta cag did not increase the release of MIF at any of the four ratios. 3H-thymidine readings for MKN-45 cells were significantly increased with supernatants derived from the wild-type strain and the mutants TN2DeltacagA and TN2DeltacagE, but not from the mutant TN2Deltacag. Moreover, in the presence of monoclonal anti-MIF antibody, the stimulatory effects of the wild-type strain on cell proliferation disappeared.

CONCLUSION

H pylori stimulates MIF release in monocytes, likely through its cag PAI, but not related to cagA or cagE. H pylori-stimulated monocyte culture supernatant increases gastric cell proliferation, which is blocked by anti-MIF antibody, suggesting that MIF plays an important role in H pylori-induced gastric epithelial cell proliferation.

Micro-managing the executioner: pathogen targeting of mitochondria

Eukaryotic cell viability is largely regulated at the level of mitochondria, with cell death executed by endogenous proteins that act to increase the permeability of the inner and/or outer membranes of these organelles. The gastric pathogen, Helicobacter pylori, can mimic this mechanism by producing the pro-apoptotic toxin, VacA, which was recently demonstrated to (i) localize to mitochondria within epithelial cells, (ii) rapidly transport into mitochondria in vitro, and (iii) induce changes consistent with permeabilization of mitochondrial membranes by a mechanism dependent on cellular entry and toxin membrane channel activity. The targeting of mitochondrial membranes is emerging as a strategy used by pathogenic microbes to control cell viability while circumventing upstream pathways and checkpoints of cell death.

Distribution of Helicobacter pylori cagA, cagE and vacA in different ethnic groups in Kuala Lumpur, Malaysia

BACKGROUND AND AIMS

There is a geographic variation in Helicobacter pylori (HP) genotypes and virulence factors. Cytotoxin associated genes A (cagA) and E (cagE), and certain vacuolating cytotoxin (vacA) genotypes are associated with peptic ulcer disease (PUD). There is also a different prevalence of PUD among different ethnic groups in Malaysia. The present study compared the distribution of vacA alleles and cagA and cagE status in three ethnic groups residing in Kuala Lumpur, Malaysia, and their association with clinical outcome.

METHODS

All patients with cultured positive HP were recruited prospectively. DNA was extracted and polymerase chain reaction was carried out to determine the cagA and cagE status and vacA alleles.

RESULTS

The results of 127 patients (72 men and 55 women) were included. The mean age was 55.53 +/- 12.52 years. The ethnic distribution was 59 Chinese, 38 Indian and 30 Malay patients. The predominant genotype was s1a among the Malay (76.6%) and Indian patients (71.0%), and s1c among the Chinese patients (66.1%). The vacA middle region sequence m1 was detected in 66.7% of Malay, 54.2% of Chinese and 76.3% of Indian patients. Of the Malay, Chinese and Indian patients, 76.6%, 86.4% and 86.8%, respectively, were cagA positive, and 70.0%, 39.0% and 81.6%, respectively, were cagE positve. HP cagA, cagE and vacA were not associated with PUD.

CONCLUSION

There is a distinctive difference in the HP strains among the three ethnic groups in Malaysia. There was no association between cagA, cagE or vacA genotypes and clinical outcome in the patients. None of these markers are helpful in predicting the clinical presentation of a HP infection.

Contemporary diagnostic and management techniques for extraesophageal reflux disease

PURPOSE OF REVIEW

To review recent advances in the diagnosis and treatment of extraesophageal reflux.

RECENT FINDINGS

For most patients, the diagnosis of extraesophageal reflux relies on history and laryngoscopic exam. The reliability and reproducibility of reporting these measures may be improved with validated symptom questionnaires and standardized scoring of physical exam findings. Though dual probe pH monitoring has been the gold standard for diagnosis, it does not measure non-acid reflux events. Intraluminal impedance monitoring has the capability of measuring all esophageal reflux events (liquid, solid, gas) and may be useful in the diagnosis of non-acid reflux. Proton pump inhibitors have replaced histamine receptor antagonists as the mainstay of treatment for extraesophageal reflux. Histamine receptor antagonists are used predominantly for nocturnal acid breakthrough, or step-down therapy. Promotility and cytoprotective agents are used less commonly. Baclofen is currently being evaluated for its ability to decrease the incidence of transient lower esophageal sphincter relaxations and reduce post-prandial acid and non-acid reflux events. For individuals refractory to medical therapy, laparoscopic fundoplication techniques have proven efficacy in relieving some symptoms; the long-term benefit is not yet known. There is yet no established data on the effects of endoluminal therapies on extraesophageal reflux symptoms.

SUMMARY

The diagnosis of extraesophageal reflux for most patients relies on history and laryngoscopic exam. The diagnosis can be further verified by dual probe pH and impedance monitoring. Proton pump inhibitors are the mainstay of treatment. Laparoscopic fundoplication is proven to relieve symptoms, but there is yet no data on the effects of endoluminal therapies on extraesophageal reflux symptoms.

The surgical treatment of gastro-esophageal reflux in neonates and infants

Gastro-esophageal reflux (GER) is a physiological process characterized by the involuntary passage of gastric contents into the lower esophagus not induced by noxious stimuli. It represents a common condition in preterm infants and may occur in healthy neonates. The phenomenon is only considered as GER disease when it causes the patient to be symptomatic or results in pathological complications. Fundoplication is recommended in symptomatic neonates and infants with GER that does not respond to medical treatment. The presence of respiratory symptoms related to GER is the primary indication for fundoplication in this selected population. The Nissen fundoplication is the antireflux procedure of choice and the experience concerning other procedures, including laparoscopic techniques, is limited in this age group. The best results are achieved in newborn infants with isolated GER, as the recurrence rate of GER in infants with associated anomalies is high. Further studies are necessary to evaluate the benefit of laparoscopic fundoplication in this age group.

Molecular biology of gastric cancer: Helicobacter infection and gastric adenocarcinoma: bacterial and host factors responsible for altered growth signaling

Gastric cancer remains the second most common cause of cancer-related mortality worldwide. The single most common cause of gastric cancer is chronic infection with the gram-negative microaerophilic spiral bacterium: Helicobacter pylori. Recent advances in this field have identified host factors which predispose to gastric cancer formation via modulation of the host immune response. In addition, recent work has explored bacterial virulence factors which may directly cause tissue damage, and lead to gastric carcinogenesis, as well as factors responsible for enhanced immune response. Environmental factors, long associated with a predilection for gastric cancer, are recognized as modifiers of key growth signalling pathways within the gastric mucosa and as such lead to growth alterations. This review focuses on exploring new advances in our understanding of bacterial factors, host genetic polymorphisms and the interaction between the bacterium and host at the level of the immune response and the regulation of proliferative and apoptotic signal transduction cascades. Modulation of the pivotal balance between cell growth and cell death leads to the formation of gastric adenocarcinoma.

The story so far: Helicobacter pylori and gastric autoimmunity

The gastric mucosal pathogen Helicobacter pylori induces autoantibodies directed against the gastric proton pump H+,K+-ATPase in 20-30% of infected patients. The presence of these autoantibodies is associated with severity of gastritis, increased atrophy, and apoptosis in the corpus mucosa, and patients with these autoantibodies infected with H. pylori display histopathological and clinical features that are similar to those of autoimmune gastritis (AIG). This review will focus on the T helper cell responses, cytokines, and adhesion molecules involved in corpus mucosal atrophy in chronic H. pylori gastritis and in AIG, and the role of H. pylori in the onset of AIG.

Use of complementary and alternative medicines by children and adolescents with inflammatory bowel disease

OBJECTIVES

The use of complementary and alternative medicines (CAM) appears increasingly prevalent in children and adolescents. Individuals with chronic illness may have patterns of greater usage. This questionnaire-based study aimed to ascertain the frequency of use by a group of children with proven inflammatory bowel disease (IBD) and to consider the reasons for their use.

METHODS

A questionnaire was sent by mail to the parents of patients currently attending a paediatric IBD clinic. Parents were asked to describe their child's usage of alternative and probiotic therapies and to comment on a number of aspects of such therapies.

RESULTS

Forty-six (77%) of 60 mailed questionnaires were returned. The mean age of the children was 10.9 (+/- 4.1) years and they were taking an average of 1.7 (+/- 0.8) prescribed medications. Thirty-three (72%) of the children were said by their parents to be having CAM, with four having five or more such therapies (average 2.4 +/- 1.3 agents per child). The most commonly used agents were probiotics (78%) and fish oils (56%). A minority (12%) of respondents reported that their child's CAM was very effective, although many (50%) noted partial benefits. The 13 children who had never used any CAM therapies ('non-users') did not differ from the 'users' in terms of gender, age, disease or duration of disease. As expected, non-users expressed greater concerns about use of CAM and described different attitudes towards such therapies.

CONCLUSION

Complementary and alternative medicines, especially probiotic therapies, frequently are administered to children and adolescents with inflammatory bowel disease. Often this appears to be due to parental frustration with managing their child's chronic illness. Practitioners caring for children and adolescents with IBD need to be aware that their patients may be using alternative therapies and adopt an open attitude in this situation.

Diagnosis of Helicobacter pylori infection and diseases associated with Helicobacter pylori by Helicobacter pylori outer membrane proteins

AIM: To examine the serological response of patients with upper gastrointestinal diseases and Helicobocter pylori (H pylori) infection to two H pylori outer membrane proteins (OMPs) (M_r18000 and M_r26000) acquired by gene recombinant technique, and to determine the diagnostic significance of serological tests derived from these OMPs.

METHODS: Recombinant vectors encoding the two H pylori OMPs were used to transform and express in BL21 (DE3) E.coli. After purification with Ni²⁺-NTA agarose resin, colloid gold kits were prepared with purified recombinant proteins to detect H pylori infection and H pylori-associated diseases by the immunity-marker technology. We selected 150 patients with H pylori infection and digestive symptoms without previous treatment, including chronic gastritis (n = 60), duodenal ulcer (n = 30), gastric ulcer (n = 30), and gastric cancer (n = 30). As controls, 33 H pylori-negative healthy volunteers were also recruited. Serum samples were collected from all subjects, and the antibodies to specific proteins of H pylori were tested with the colloid gold test kits. The sensitivity, specificity and accuracy of the colloid gold tests were evaluated, by using the combination of standard diagnostic methods (¹³C urea breath test and bacteria culture) and classic enzyme-linked immunosorbent assay (ELISA) as reference.

RESULTS: After purification with Ni²⁺-NTA agarose resin, the purity of recombinant fusion proteins was about 95%. The recombinant fusion proteins were recognized by the specific monoclonal antibodies against the two H pylori OMPs, as demonstrated by the ELISA. Of the 150 serum samples from patients infected with H pylori 141 (94.0%) responded positively to the recombinant protein with M_r26000, while the seropositive rates were 95.0%, 96.7%, 96.7% and 90.0% for patients with H pylori-associated chronic gastritis, duodenal ulcer, gastric ulcer, and gastric cancer respectively. The sensitivity, specificity, and accuracy of the colloid gold kit with M_r26000 protein were 94.0%, 97.0%, and 94.5%, respectively. Compared with the classic ELISA, bacteria culture and ¹³C urea breath test results in detecting H pylori-infection, there was no significant difference (P > 0.05). For the colloid gold kit with M_r18000, the seropositive rates were 52.0%, 40.0%, 40.0%, 53.3% and 86.7%, respectively, in H pylori-infected patients, and those with H pylori-associated chronic gastritis, duodenal ulcer, gastric ulcer, and gastric cancer. There was a significant difference (P < 0.05) in seropositivity between patient with gastric cancer (86.7%) and those with other diseases (43.3%).

CONCLUSION: The two colloid gold kits derived from the recombinant OMPs are useful tools either for detecting H pylori infection, or for, predicting H pylori-associated gastric malignancy.

Analysis of gene expression profile in gastric cancer cells stimulated with Helicobacter pylori isogenic strains

To understand the biological processes within host cells induced by VacA, isogenic strains of Helicobacter pylori (NCTC 11638 or 11638-DeltavacA) were used to stimulate gastric cancer cells SGC7901, and differentially expressed genes in host cells were identified using cDNA microarray technology. More than 300 genes were found to alter their mRNA expression at different time points, among which 68 were related to the cytoskeleton, 87 were associated with cell cycle, cell death and proliferation, IL8 expression was also found to be up-regulated. Cells co-cultured with broth-culture supernatant (BCS) of NCTC 11638 showed more alteration in microtubule cytoskeleton morphology, as observed by laser scanning confocal microscopy, and a lower apoptosis rate, detected by flow cytometry, compared with those co-cultured with BCS of 11638-DeltavacA. The supernatants of cells co-cultured with NCTC 11638 showed significantly higher IL8 expression than those co-cultured with 11638-DeltavacA. It is concluded that VacA disrupts cytoskeletal architecture by influencing the expression of cytoskeleton-associated genes. VacA breaks the balance between cell proliferation and cell death by inducing the maladjustment of genes related to cell cycle. VacA is also able to induce the inflammatory response.

Review article: 13C-urea breath test in the diagnosis of Helicobacter pylori infection -- a critical review

The urea breath test is a non-invasive, simple and safe test which provides excellent accuracy both for the initial diagnosis of Helicobacter pylori infection and for the confirmation of its eradication after treatment. Some studies have found no differences between urea breath test performed under non-fasting conditions. The simplicity, good tolerance and economy of the citric acid test meal probably make its systematic use advisable. The urea breath test protocol may be performed with relatively low doses (<100 mg) of urea: 75 mg or even 50 mg seem to be sufficient. With the most widely used protocol (with citric acid and 75 mg of urea), excellent accuracy is obtained when breath samples are collected as early as 10-15 min after urea ingestion. A unique and generally proposed cut-off level is not possible because it has to be adapted to different factors, such as the test meal, the dose and type of urea, or the pre-/post-treatment setting. Fortunately, because positive and negative urea breath test results tend to cluster outside of the range between 2 and 5 per thousand, a change in cut-off value within this range would be expected to have little effect on clinical accuracy of the test.

Efficacy of conventional immunosuppressive drugs in IBD

The introduction and rapid diffusion of biological agents in the treatment of inflammatory bowel disease had led us to believe that the old immunosuppressive drugs were destined to disappear. However, despite a decade of clinical experience in the use of biological agents, the old immunosuppressive drugs continue to play a pivotal role in the management of inflammatory bowel disease. Various factors may account for this change of view. Aim of the present review was to summarise key information currently available regarding the use of immunosuppressive drugs in the treatment of inflammatory bowel disease.

Helicobacter pylori infection induces interleukin-18 production in gastric epithelial (AGS) cells

Helicobacter pylori colonization of the stomach results in a chronic-active gastritis characterized by mucosal infiltration of both neutrophils and lymphocytes. A T helper lymphocyte (Th1) profile predominates, which promotes the chronic and persistent inflammatory changes in the gastric mucosa in response to this bacterial pathogen. The cytokine interleukin-18 induces production of interferon-gamma by activated T lymphocytes and promotes a Th1 profile. An in vitro model system was utilized to determine the role of interleukin-18 in response to infection of gastric epithelial cells by H. pylori. H. pylori isolates, characterized with respect to cagE and cagA and VacA status, were employed to infect AGS gastric epithelial cells. Interleukin-18 production was determined by immunoassay. Infection of AGS cells with H. pylori resulted in a 1.8-fold increase in interleukin-18 compared to uninfected cells (22.7+/-2.4 vs. 12.7+/-2.2 pg/ml; P < 0.005). This interleukin-18 response was independent of the cagE status of infecting strains (23.3+/-1.9 vs. 26.3+/-3.6 pg/ml; P = NS). Exposure of AGS cells to recombinant interleukin-18 resulted in dose-dependent and time-dependent secretion of interleukin-8 that was maximal following exposure to 100 pg/ml interleukin-18 for 24 hr (292+/-5 pg/ml, versus 102+/-14 pg/ml in unstimulated cells; P < 0.001). Interleukin-8 secretion was inhibited following pretreatment of cells with anti-interleukin-18 antibody and by pharmacological inhibition of the nuclear transcription factor, NF-kappaB. These findings demonstrate that interleukin-18 can enhance host chemokine response to H. pylori infection.

Targeting therapy in pediatric inflammatory bowel disease

Progress in our understanding of the interaction between the environment and the immune system in disease pathogenesis has led to major advancements in the area of inflammatory bowel disease (IBD) therapeutics. Biotechnology is keeping pace with these scientific advances. Current therapies target the various elements of the inflammatory cascade implicated in the pathogenesis of IBD. The anti-inflammatory and immunomodulatory properties of the pharmacologic therapies used in IBD vary from actions that are extremely broad to those that are cellular or cytokine specific. Despite the various therapeutic options available for IBD patients, chosen therapies should be based on the overall treatment goal for individual patients. Therapeutics can be broadly categorized as induction therapies (goal to treat active disease) and maintenance therapies (goal to prevent relapse of disease). The modern thinking behind drug development is that IBD therapy should be disease modifying so to avoid complications and alter the long term natural history of disease. This review will cover both current and emerging agents and highlight the pathogenesis of IBD and how it relates to therapeutic targets.

Gastric transcription profile of Helicobacter pylori infection in the rhesus macaque

Infection with Helicobacter pylori is usually asymptomatic but sometimes progresses to peptic ulcer disease or gastric adenocarcinoma. The development of disease involves both host and bacterial factors. In order to better understand host factors in pathogenesis, we studied the gastric transcription profile of H. pylori infection in the rhesus macaque by using DNA microarrays. Significant changes were found in the expression of genes important for innate immunity, chemokines and cytokines, cell growth and differentiation, apoptosis, structural proteins, and signal transduction and transcription factors. This broad transcription profile demonstrated expected up-regulation of cell structural elements and the host inflammatory and immune response, as well as the novel finding of down-regulation of heat shock proteins. These results provide a unique view of acute H. pylori infection in a relevant animal model system and will direct future studies regarding the host response to H. pylori infection.

Gastric epithelial cell CXC chemokine secretion following Helicobacter pylori infection in vitro

BACKGROUND AND AIMS

Helicobacter pylori infection of the stomach is commonly associated with infiltration of neutrophils. Gastric epithelial cells are recognized as central mediators of tissue responses to this organism. The aim of the present study was to ascertain patterns of production of three neutrophil chemoattractant chemokines following infection of gastric epithelial cells with H. pylori in vitro.

METHODS

Two gastric cancer-derived epithelial cell lines were infected with H. pylori organisms of previously defined cagE and cagA status for periods of up to 24 h. The production of three chemokines (interleukin [IL]-8, epithelial neutrophil activating protein [ENA]-78 and growth-related oncogene [GRO]-alpha) over this time was measured in culture supernatants using immunoassays.

RESULTS

Both IL-8 and GRO-alpha were produced by both AGS and KATO-III cells in response to H. pylori infection, and in a cag PAI-dependent manner. ENA-78, however, was not increased following H. pylori infection.

CONCLUSIONS

GRO-alpha is expressed by epithelial cells following H. pylori infection along with IL-8. Both may contribute to neutrophilic infiltration present in gastric mucosa associated with H. pylori infection. In contrast, H. pylori infection does not lead to an increased synthesis of ENA-78, suggesting that this may not be as important in vivo.

A model for the study of Helicobacter pylori interaction with human gastric acid secretion

We present a comprehensive mathematical model describing Helicobacter pylori interaction with the human gastric acid secretion system. We use the model to explore host and bacterial conditions that allow persistent infection to develop and be maintained. Our results show that upon colonization, there is a transient period (day 1-20 post-infection) prior to the establishment of persistence. During this period, changes to host gastric physiology occur including elevations in positive effectors of acid secretion (such as gastrin and histamine). This is promoted by reduced somatostatin levels, an inhibitor of acid release. We suggest that these changes comprise compensatory mechanisms aimed at restoring acid to pre-infection levels. We also show that ammonia produced by bacteria sufficiently buffers acid promoting bacteria survival and growth.

Diagnosis of Helicobacter pylori infection

While there are some attempts to improve culture of Helicobacter pylori, molecular methods have been the main focus of this interest. Their main application concerns the development of rapid tests also allowing the determination of bacterial resistance, i.e. real-time polymerase chain reaction (PCR) or fluorescence in situ hybridization (FISH), or to genotype the strains. Attempts to improve, simplify or explain the discrepancies of urea breath test results have been made and new generation of stool antigen test with monoclonal antibodies either using the standard ELISA format or rapid immunoenzymatic detection have confirmed their value. With regard to serology, studies have mainly focused on the distinction of infections with more pathogenic strains and the ability to diagnose atrophic gastritis with the Gastropanel.

Probiotics reduce bacterial colonization and gastric inflammation in H. pylori-infected mice

Probiotics are characterized by their ability to interact with commensal microflora in the gastrointestinal tract to produce beneficial health effects. In vitro studies suggest that Lactobacillus species have the potential to suppress the growth of Helicobacter pylori. The goal of this study was to determine if pretreatment of mice with a commercial mixture of live probiotics (L. rhamnosus, strain R0011, and L. acidophilus, strain R0052) would suppress colonization of H. pylori, strain SS1. Thirty C57BL/6 female mice were divided into four groups: Group A was fed sterile water, group B received probiotics in sterile drinking water, group C was challenged orogastrically with H. pylori, and group D was pretreated with probiotics in drinking water prior to and following challenge with H. pylori. Rectal swabs, stomach homogenates, and luminal contents from ileum and colon were plated onto colistin nalidixic acid plates. Serial dilutions of stomach homogenates were plated onto H. pylori-sensitive agar plates and incubated under microaerophilic conditions. Tissue samples from the stomach were analyzed histologically to determine the degree of H. pylori colonization, mucosal inflammation, and epithelial cell apoptosis. Probiotics in drinking water did not affect the overall well-being of mice. Lactobacillus species were excreted in stools over the entire duration of treatment. Pretreatment with probiotics reduced the number of mice with H. pylori growth from stomach homgenates (100 to 50%; P = 0.02). The percentage of mice with moderate-severe H. pylori-induced inflammation in the gastric antrum was reduced with probiotic pretreatment (71 to 29%; P = 0.14). However, pretreatment with probiotics did not prevent H. pylori-induced apoptosis in the gastric mucosa. This preparation of probiotics provided a safe and novel approach for reducing H. pylori colonization and bacterial-induced inflammation of mice.

Helicobacter pylori infection in pediatrics

The proposed route of Helicobacter pylori transmission appears to be fecal-oral, oral-oral and gastro-oral, yet, a number of studies challenged these hypotheses in 2003. The use of the stool antigen test and[13]-C urea breath testing were the tests of choice for diagnosis and 'test for cure' of H. pylori in Europe in 2003 but have not yet become accepted standard of care in North America. Pediatric H. pylori consensus guidelines are not yet revised; upper endoscopy and biopsy remain the gold standard for diagnosis of pediatric H. pylori infection. In addition to stronger evidence supporting the role of host influences of H. pylori-associated gastric cancer risk, compelling evidence was provided for the role of H. pylori in iron deficiency anemia of childhood. Antibiotic resistance remains a problem in conferring treatment failure and 2003 studies indicate that macrolide resistance is higher in children than in adults. Treatment with proton pump inhibitor-based triple therapy for 10-14 days remains the mainstay for eradication of H. pylori in childhood. Finally, multinational studies are needed to develop screening guidelines for childhood infection to avoid long-term severe gastroduodenal disease sequelae.

Probiotics reduce bacterial colonization and gastric inflammation in H. pylori-infected mice

Probiotics are characterized by their ability to interact with commensal microflora in the gastrointestinal tract to produce beneficial health effects. In vitro studies suggest that Lactobacillus species have the potential to suppress the growth of Helicobacter pylori. The goal of this study was to determine if pretreatment of mice with a commercial mixture of live probiotics (L. rhamnosus, strain R0011, and L. acidophilus, strain R0052) would suppress colonization of H. pylori, strain SS1. Thirty C57BL/6 female mice were divided into four groups: Group A was fed sterile water, group B received probiotics in sterile drinking water, group C was challenged orogastrically with H. pylori, and group D was pretreated with probiotics in drinking water prior to and following challenge with H. pylori. Rectal swabs, stomach homogenates, and luminal contents from ileum and colon were plated onto colistin nalidixic acid plates. Serial dilutions of stomach homogenates were plated onto H. pylori-sensitive agar plates and incubated under microaerophilic conditions. Tissue samples from the stomach were analyzed histologically to determine the degree of H. pylori colonization, mucosal inflammation, and epithelial cell apoptosis. Probiotics in drinking water did not affect the overall well-being of mice. Lactobacillus species were excreted in stools over the entire duration of treatment. Pretreatment with probiotics reduced the number of mice with H. pylori growth from stomach homgenates (100 to 50%; P = 0.02). The percentage of mice with moderate-severe H. pylori-induced inflammation in the gastric antrum was reduced with probiotic pretreatment (71 to 29%; P = 0.14). However, pretreatment with probiotics did not prevent H. pylori-induced apoptosis in the gastric mucosa. This preparation of probiotics provided a safe and novel approach for reducing H. pylori colonization and bacterial-induced inflammation of mice.

Novel activities of the Helicobacter pylori vacuolating cytotoxin: from epithelial cells towards the immune system

H. pylori has developed a unique set of virulence factors, which allow its survival in a unique ecological niche, the human stomach. The vacuolating cytotoxin (VacA) and the cytotoxin-associated antigen (CagA) are major bacterial factors involved in modulating the host. VacA, so far mainly regarded as a cytotoxin for the gastric epithelial cell layer, apparently has profound effects in modulating the immune response. In this review we discuss some of the classical effects of VacA, such as cell vacuolation, and compare them with more recently identified mechanisms of VacA on immune cells.

Helicobacter pylori outer membrane proteins in diagnosis of Helicobacter pylori infection

AIM: To examine the serological response of patient with various upper gastrointestinal diseases and Helicobacter pylori (H. pylori ) infection to H. pylori outer membrane proteins (OMP) with M_r18 000 and 26 000 acquired by gene recombinant technique, and to determine its diagnostic significance.

METHODS: The recombinant vectors encoding OMP of H. pylori with M_r18 000 and 26 000 identified by restriction enzyme or PCR were used to transform and express in BL21 (DE3) E. coli respectively. After purification with Ni²⁺-NTA agarose resin, the colloid gold kits were prepared with purified recombinant proteins to detect H. pylori infection and disease associated with H. pylori by immunity-marker technology. We selected 150 patients with H. pylori infection and digestive symptoms without previous treatment, including chronic superficial gastritis (n = 60), duodenal ulcer (n = 30), gastric ulcer (n = 30), and gastric cancer (n = 30) during one year. Simultaneously, 33 cases without digestive symptoms and H. pylori infection were used as controls. All sera were collected and the antibody responded to specific proteins of H. pylori was tested with the colloid gold test kit. Taking as reference a combination of standard diagnostic methods (¹³C urea breath test, cultivate) and the classic enzyme-linked immunosorbent assay (ELISA) serological tests was compared with the results of this technique, and the sensitivity, specificity and accuracy of the colloid gold test were evaluated.

RESULTS: After purification with Ni²⁺-NTA agarose resin, the purities of recombinant fusion proteins were all about 95%. The ELISA results showed that recombinant fusion proteins could be recognized by monoclonal antibody of anti-H. pylori with Mr18 000 and 26 000 respectively. The results detected using colloid gold kits were as follows: all patients sera infected with H. pylori showed response to recombinant protein with M_r 26 000 were 94.0%, while 95.0%, 96.7%, 96.7% and 90.0% of patients with H. pylori-infected chronic superficial gastritis, duodenal ulcer, gastric ulcer, and gastric cancer respectively, showed responses. Compared with the serum-based ELISA results in detecting H. pylori-infection, there was no significant difference with the colloid gold kits (P > 0.05). The sensitivity, specificity, and accuracy of the rapid test kit with Mr 26 000 protein were 94.0%, 97.0%, and 94.5%, respectively; To recombinant protein with M_r18 000, 52.0%, 40.0%, 40.0%, 53.3% and 86.7%, of patients with H. pylori-infected chronic superficial gastritis, duodenal ulcer, gastric ulcer, and gastric cancer respectively, showed responses. There were a significant difference (P < 0.05) in the detecting rates of H. pylori infection between gastric cancer (86.7%) and the other diseases (43.3%). The results showed the colloid gold kits with Mr26 000 proteins of H. pylori could be used as a conventional examination method, with similar sensitivity and specificity as other conventional examination method, and simultaneously a significant association was found between the serologic response to M_r 18 000 OMP antigen and malignant outcome of H. pylori infection.

CONCLUSION: The two colloid gold kits with M_r18 000 and 26 000 proteins of H. pylori, can be a useful tool for detecting H. pylori infection, as well as predicting H. pylori related gastrointestinal diseases, such as gastric malignancy and peptic ulcer.

Successful therapy of refractory pyoderma gangrenosum and periorbital phlegmona with tacrolimus (FK506) in ulcerative colitis

We describe two male patients with ulcerative colitis and refractory pyoderma gangrenosum including periorbital phlegmona in one case. Both patients were successfully managed with low dose oral tacrolimus (0.1 mg/kg bodyweight per day). Serum trough levels were closely monitored and maintained between 4 and 6 ng/mL. A rapid response was noted in both cases. Complete non-scarring skin restitution without side effects was accomplished in both cases. Low dose oral tacrolimus provides a valuable alternative treatment option for IBD patients with refractory pyoderma gangrenosum.

Helicobacter pylori induces apoptosis of macrophages in association with alterations in the mitochondrial pathway

Helicobacter pylori is a gastric bacterial pathogen that evades host immune responses in vivo and is associated with the development of gastritis, peptic ulcer disease, and gastric cancers. Induction of macrophage apoptosis is a method employed by multiple pathogens to escape host immune responses. Therefore, we hypothesized that H. pylori induces apoptosis of infected macrophages. RAW 264.7 cells were infected with H. pylori strain 60190, and apoptosis was assessed. Transmission electron microscopy and fluorescence microscopy showed that infected macrophages displayed morphological features characteristic of apoptosis. Quantification by acridine orange-ethidium bromide fluorescent-dye staining showed that apoptosis was dose and time dependent, and apoptosis was further confirmed by increased binding of annexin V-fluorescein isothiocyanate (FITC) to externalized phosphatidylserine of infected but not of control macrophages. Macrophages infected with isogenic mutants of H. pylori strain 60190 deficient in either cagA or vacA induced significantly less apoptosis than the parental strain, as assessed by increased binding of annexin V-FITC. Western blot analysis of whole-cell protein lysates revealed that infection with strain 60190 induced a time-dependent increase in cleavage of procaspase 8 and disappearance of full-length Bid compared with uninfected cells. Furthermore, pharmacological inhibition of caspase 8 caused a decrease in levels of apoptosis. Finally, infection caused a time-dependent increase in mitochondrial-membrane permeability and release of cytochrome c into the cytosol. These results suggest that H. pylori induces apoptosis of macrophages in association with alterations in the mitochondrial pathway. Elimination of this key immunomodulatory cell may represent a mechanism employed by the bacterium to evade host immune responses.

Medical management of severe ulcerative colitis

The medical management of patients with severe ulcerative colitis requires initial stabilization, careful and repeated evaluations to exclude confounding or coexisting diagnoses, and timely delivery of appropriate medications. Medical therapies for these patients are potent but may be toxic, and administration must be done by experienced medical professionals, with adequate access to appropriate laboratory, radiographic, endoscopic, and surgical facilities. Patients who fail to respond to high-dose intravenous corticosteroids in a timely basis should be evaluated for cyclosporin therapy, or proceed to surgery. The promise of newer, investigational therapies to induce and maintain remission must be borne out by large controlled trials.

Medical management of the pregnant patient with inflammatory bowel disease

Gastroenterologists are not infrequently faced with questions regarding pregnancy when advising or treating their patients with inflammatory bowel disease (IBD). To advise patients effectively, the following factors must be considered: (1) the inheritance patterns of IBD for accurate counseling and family planning; (2) the effects of active IBD versus medications or surgery on fertility; (3) the effects of pregnancy on the course of IBD; (4) the effects and potential risks of active IBD versus those of diagnostic tests, medical treatments, and surgical treatments on the developing fetus; (5) approach to delivery; and (6) the risks of breast-feeding while receiving treatment for IBD.

Cyclosporine, tacrolimus, and mycophenolate mofetil in the treatment of inflammatory bowel disease

In the past decade, immunosuppressive drugs have come to play an integral role in the treatment of patients with inflammatory bowel disease. Cyclosporine, microemulsion cyclosporine, tacrolimus, and mycophenolate mofetil can be considered for the treatment of patients with refractory inflammatory Crohn's disease, fistulizing Crohn's disease, and severe ulcerative colitis. This article reviews the use of cyclosporine, tacrolimus, and mycophenolate mofetil in patients with inflammatory bowel disease, with emphasis on pharmacology, results in controlled clinical trials, and safety, and issues related to dosing and toxicity monitoring.

Bax translocation and mitochondrial fragmentation induced by Helicobacter pylori

BACKGROUND AND AIMS

Previous in vitro and in vivo studies have revealed an association between Helicobacter pylori infection and apoptosis in gastric epithelial cells. Although involvement of the Bcl-2 family of proteins as well as cytochrome c release has been demonstrated in H pylori induced cell death, the exact role of the mitochondria during this type of programmed cell death has not been fully elucidated. Therefore, we sought to determine whether or not Bax translocation and mitochondrial fragmentation occur on exposure of gastric epithelial cells to H pylori, resulting in cell death.

METHODS

Experiments were performed with human gastric adenocarcinoma (AGS) cells, AGS cells transfected with the HPV-E6 gene (which inactivates p53 function), AGS-neo cells (transfected with the backbone construct), mouse embryonic fibroblasts (MEFs), and p19(ARF) null (ARF(-/-)) MEFs. Cells were incubated with a cag positive H pylori strain for up to 24 hours, lysed, and cytoplasmic and mitochondrial membrane fractions were analysed by western blot for Bax translocation.

RESULTS

Bax translocation was detected in AGS, AGS-neo, and normal MEF cells after exposure to H pylori for three hours, but not in ARF(-/-) MEFs cells. Translocation of Bax after H pylori incubation was also detected in AGS-E6 cells (inactive p53 gene) but to a lesser degree than in AGS-neo cells. In parallel studies, the mitochondrial morphology of living cells infected with H pylori was assessed by confocal microscopy. Mitochondrial fragmentation was detectable after 10 hours of H pylori incubation with AGS cells and after seven hours with MEF cells. In wild-type MEFs, mitochondrial fragmentation was significantly increased in comparison with ARF null MEFs (43% v 10.4%, respectively). Furthermore, mitochondrial depolarisation and caspase-3 activity were initiated within four hours in cells incubated with H pylori, and these events were inhibited by forced expression of Bcl-2.

CONCLUSIONS

These data suggest that during H pylori induced apoptosis, Bax translocates to the mitochondria which subsequently undergo depolarisation and profound fragmentation. Functional ARF and p53 proteins may play an important role in H pylori induced mitochondrial modification.

Medical therapy for ulcerative colitis 2004

There continue to be evolutionary changes in the management of ulcerative colitis despite the fact that, aside from a variety of aminosalicylate formulations, no new therapies have been approved over the past few decades. Nevertheless, debates continue regarding the optimization of treatment with aminosalicylates and the short- and long-term benefits of immunomodulation in ulcerative colitis. This article focuses on the most recent clinical studies pertaining to the management of ulcerative colitis and explores both the advances and controversies pertaining to aminosalicylate therapy, corticosteroids, cyclosporine, and the purine antimetabolites. Novel therapeutic approaches--including preliminary experience with biological therapies directed at tumor necrosis factor and other cytokines, adhesion molecules, growth factors, and probiotics--will be reviewed. Recent data regarding potential chemoprevention in long-standing ulcerative colitis and management of postoperative complications and pouchitis will also be discussed.

Review article: How useful are the rodent animal models of gastric adenocarcinoma?

Gastric cancer is the second most common cause of cancer-related mortality world-wide. In most cases, it develops via the pre-malignant stages of atrophic gastritis, intestinal metaplasia and dysplasia, following Helicobacter pylori infection of susceptible individuals. A number of rodent models have recently provided valuable insights into the host, bacterial and environmental factors involved in gastric carcinogenesis. Wild-type rodents do not develop gastric adenocarcinoma, but early studies showed that the disease could be induced in several rodent species by chemical carcinogens. More recently, it has been demonstrated that gastric adenocarcinoma can be induced in Mongolian gerbils by H. pylori infection and in C57BL/6 mice by long-term H. felis infection. These models have allowed the importance of Helicobacter virulence genes, host factors, such as gender, strain and immune response, and environmental factors, such as dietary salt, to be explored. A number of transgenic mice with alterations in various pathways, including the immune response, gastrin biosynthesis, parietal cell development, growth factors and tumour suppressors, have also provided models of various stages of gastric carcinogenesis. One model that has proved to be particularly valuable is the hypergastrinaemic INS-GAS mouse, in which gastric carcinoma develops spontaneously in old animals, but the process is greatly accelerated by Helicobacter infection.

Current therapy of ulcerative colitis in children

Ulcerative colitis presents in childhood in 10% of those affected, usually with pancolitis. Important features in management include growth, development and avoidance of treatment toxicity. This review addresses the current treatment options including both the paediatric evidence-based experience and areas where paediatric practice is informed by adult studies. Standard treatments include sulfasalazine or 5-aminosalicylates, corticosteroids, purine derivatives (azathioprine or 6-mercaptopurine) and surgery. Other immunosuppressant therapies and the emerging roles for biological therapies and probiotics are discussed.

Management guidelines for Helicobacter pylori infection: utilization by paediatric gastroenterologists in Australasia

OBJECTIVE

Although there are published guidelines representing the consensus of several large groups, it is unclear whether these are used by practitioners in the management of Helicobacter pylori infection in children and if the guidelines are relevant to particular regions of the world. The aim of this study was to answer these questions in regard to the Australasian region.

METHODS

An email-based questionnaire was circulated to Australasian paediatric gastroenterologists to ascertain aspects of practice related to H. pylori infection in children and to review practitioner awareness and use of the guidelines.

RESULTS

Twenty-five (78%) of 32 questionnaires were completed. Current practice reported by the respondents followed the principles of the published guidelines. However, only 15 gastroenterologists were aware of the guidelines: a number of these practitioners were uncomfortable adapting the published guidelines to their local situation.

CONCLUSIONS

Although widely distributed in the paediatric gastroenterology literature, guidelines for management of H. pylori infection may not be utilized fully by individual practitioners. As these guidelines are updated, based upon current developments in the understanding of H. pylori disease, attempts should be made to ensure that such documents are widely distributed to practitioners and that they reflect regional variations in disease patterns.

Helicobacter pylori vacuolating cytotoxin enters cells, localizes to the mitochondria, and induces mitochondrial membrane permeability changes correlated to toxin channel activity

The Helicobacter pylori vacuolating cytotoxin (VacA) intoxicates mammalian cells resulting in reduction of mitochondrial transmembrane potential (Delta Psi m reduction) and cytochrome c release, two events consistent with the modulation of mitochondrial membrane permeability. We now demonstrate that the entry of VacA into cells and the capacity of VacA to form anion-selective channels are both essential for Delta Psi m reduction and cytochrome c release. Subsequent to cell entry, a substantial fraction of VacA localizes to the mitochondria. Neither Delta Psi m reduction nor cytochrome c release within VacA-intoxicated cells requires cellular caspase activity. Moreover, VacA cellular activity is not sensitive to cyclosporin A, suggesting that VacA does not induce the mitochondrial permeability transition as a mechanism for Delta Psi m reduction and cytochrome c release. Time-course and dose-response studies indicate that Delta Psi m reduction occurs substantially before and at lower concentrations of VacA than cytochrome c release. Collectively, these results support a model that VacA enters mammalian cells, localizes to the mitochondria, and modulates mitochondrial membrane permeability by a mechanism dependent on toxin channel activity ultimately resulting in cytochrome c release. This model represents a novel mechanism for regulation of a mitochondrial-dependent apoptosis pathway by a bacterial toxin.

Fascination with bacteria-triggered cell death: the significance of Fas-mediated apoptosis during bacterial infection in vivo

Increasing evidence indicates that bacterial pathogens have developed mechanisms to modulate the apoptotic signaling cascade of host cells and thereby cause disease. The Fas death receptor pathway is one of the most extensively investigated apoptotic signaling pathways. In this review we discuss the role of Fas signaling during the interplay between bacterial pathogens and the host in vivo.

Persistent infection with Helicobacter pylori and the development of gastric cancer

Gastric malignancies have been closely linked to infection of the gastric mucosa with Helicobacter pylori, but the individual factors involved in the multistage process of tumor development are still poorly understood. H. pylori evades the host defense system and causes persistent infection and chronic inflammation. Immune activation leads to DNA damage by the release of oxygen and nitrogen radicals. Ongoing tissue repair mechanisms and the secretion of cytokines and growth factors, as well as bacterial effector molecules, cause disturbances in the balance between epithelial cell proliferation and apoptosis, promote the accumulation of potential oncogenic mutations, and support neovascularization and tumor growth. In addition, H. pylori might hamper the development of an efficient antitumor immunity and provoke immune-mediated pathology. This review summarizes the recent progress in the understanding of the intimate bacteria-host relationship and the mechanisms by which H. pylori may promote the process of tumor development.

Helicobacter pylori disrupts STAT1-mediated gamma interferon-induced signal transduction in epithelial cells

Infection with Helicobacter pylori is chronic despite a vigorous mucosal immune response characterized by gastric T-helper type 1 cell expansion and gamma interferon (IFN-gamma) production. IFN-gamma signals by activation and nuclear translocation of signal transducer and activator of transcription 1 (STAT1); however, the effect of H. pylori infection on IFN-gamma-STAT1 signaling is unknown. We infected human gastric (MKN45 and AGS) and laryngeal (HEp-2) epithelial cell lines with type 1 and type 2 H. pylori strains and then stimulated them with IFN-gamma. Western blotting of whole-cell protein extracts revealed that infection with live, but not heat-killed, H. pylori time-dependently decreased IFN-gamma-induced STAT1 tyrosine phosphorylation. Electrophoretic mobility shift assay of nuclear protein extracts demonstrated that H. pylori infection reduced IFN-gamma-induced STAT1 DNA binding. STAT1 was unable to translocate from the cytoplasm to the nucleus in H. pylori-infected HEp-2 cells examined by immunofluorescence, and reverse transcription-PCR showed that IFN-gamma-induced interferon regulatory factor 1 expression was inhibited. These effects were independent of the cagA, cagE, and VacA status of the infecting H. pylori strain. Furthermore, neither H. pylori culture supernatants nor conditioned medium from H. pylori-infected MKN45 cells inhibited IFN-gamma-induced STAT1 tyrosine phosphorylation, suggesting that inhibition is independent of a soluble epithelial or bacterial factor but is dependent on bacterial contact with epithelial cells. H. pylori disruption of IFN-gamma-STAT1 signaling in epithelial cells may represent a mechanism by which the bacterium modifies mucosal immune responses to promote its survival in the human host.

Medical treatment of ulcerative colitis

Ulcerative colitis is a chronic inflammatory disease of the colon with an increasing incidence worldwide. The medical management of this disease continues to expand as drugs to induce and maintain remission are sought to avoid the need for colectomy. This article will review the standard of care for the treatment of mild, moderate, and severe ulcerative colitis. The efficacy, optimal usage, and adverse events profile of agents such as 5-aminosalicylates, corticosteroids, azathioprine, and cyclosporine will be discussed and an algorithm for their use will be developed. Alternative and experimental therapies such as monoclonal antibodies, probiotics, and heparin will also be addressed.

Helicobacter pylori infection in pediatric population: epidemiology, pathophysiology, and therapy

Helicobacter pylori, one of the most commonly encountered human pathogens, has been recognized in more than half of adults and children with chronic nonspecific gastritis, and nearly all children with peptic ulcer disease demonstrate antral infection with H. pylori. A high prevalence and early colonization of H. pylori infection in childhood was described in developing countries in contrast to developed countries. The current diagnostic methods include histology, microbiological culture, urease activity detection, polymerase chain reaction, and stool antigen detection. The infection often presents with nausea, vomiting, and epigastric pain but may remain asymptomatic. The treatment modality options are multiple; however, the association of a proton-pump inhibitor and two antibiotics for 1 or 2 weeks gives the best eradication rates. Drug resistance is a growing problem in this microorganism and new therapeutic options are currently limited.

Patterns and perceptions of complementary/alternative medicine among paediatricians and patients' mothers: a review of the literature

For many families and their children, the use of complementary/alternative medicine (CAM) is an accepted adjunct or alternative to conventional therapy, even if data available in the literature regarding risks and adverse drug reactions (ADRs) pertaining to childhood populations are scarce. Moreover, despite widespread and increasing use of CAM, there are limited data on how paediatricians communicate with mothers and/or patients about CAM. Therefore, we report the studies available in the literature in the paediatric field and summarise what is known about ADRs and risks of CAM, taking into account in particular problems related to interactions between phytotherapy and conventional medicines and to counselling.

CONCLUSION

from the analysis of the literature, some interesting aspects emerge: (1) the extent of CAM use in the paediatric field is increasingly sought by parents of children with chronic illnesses; (2) most parents who choose CAM medicine for their children believe that these therapies are "natural" and thus "safe" and (3) physicians often feel to know too little about CAM and wish to learn more for different reasons including "to dissuade whether the alternative method is unsafe and/or ineffective". Therefore, paediatricians should be prepared to discuss alternative therapies with parents, since talking about CAM may help to minimise the risks and to restrain parental misconceptions and doubts. Educational interventions for parents should also be performed to bring about a more aware use of traditional and alternative medicines.

Cellular vacuolation and mitochondrial cytochrome c release are independent outcomes of Helicobacter pylori vacuolating cytotoxin activity that are each dependent on membrane channel formation

Helicobacter pylori vacuolating toxin (VacA) is a secreted toxin that is reported to produce multiple effects on mammalian cells. In this study, we explored the relationship between VacA-induced cellular vacuolation and VacA-induced cytochrome c release from mitochondria. Within intoxicated cells, vacuolation precedes cytochrome c release and occurs at lower VacA concentrations, indicating that cellular vacuolation is not a downstream consequence of cytochrome c release. Conversely, bafilomycin A1 blocks VacA-induced vacuolation but not VacA-induced cytochrome c release, which indicates that cytochrome c release is not a downstream consequence of cellular vacuolation. Acid activation of purified VacA is required for entry of VacA into cells, and correspondingly, acid activation of the toxin is required for both vacuolation and cytochrome c release, which suggests that VacA must enter cells to produce these two effects. Single amino acid substitutions (P9A and G14A) that ablate vacuolating activity and membrane channel-forming activity render VacA unable to induce cytochrome c release. Channel blockers known to inhibit cellular vacuolation and VacA membrane channel activity also inhibit cytochrome c release. These data indicate that cellular vacuolation and mitochondrial cytochrome c release are two independent outcomes of VacA intoxication and that both effects are dependent on the formation of anion-selective membrane channels.

Fatal Type 3 Adenoviral Pneumonia in Immunocompetent Adult Identical Twins

We describe adult twin sisters who developed severe adenoviral pneumonia with relative leukopenia, progressive focal infiltrates, shock, and hypoxia. Potential determinants of severe adenoviral disease are discussed.

CagA antibodies as a marker of virulence in chilean patients with Helicobacter pylori infection

BACKGROUND

The bacterial and host factors that influence the clinical outcomes of the Helicobacter pylori infection have not been fully identified. Cytotoxin-associated gene product (CagA), one of the virulence factors, has been associated with a more aggressive form of infection. The authors studied the relationship between CagA status and clinical outcome in Chilean children and adults with H. pylori infection.

METHODS

One hundred eighty consecutive patients undergoing upper gastrointestinal endoscopic analysis were enrolled after informed consent was obtained. Rapid urease test and histologic analysis were used to detect H. pylori infection. IgA and IgG antibodies to H. pylori whole cell antigen preparation and IgG antibodies to CagA were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

H. pylori infection was detected in 42% of the patients by biopsy or urease test and in 38% and 20% of patients by IgG and IgA antibodies, respectively. The prevalence of H. pylori either by the invasive or the serologic tests was directly related to patient age. Among patients with H. pylori, there was no significant association between age and prevalence of CagA. Nearly 70% of the patients with H. pylori and peptic ulcer disease had CagA-positive strains. In contrast, only 49% of the patients with chronic gastritis alone had CagA-positive strains (P < 0.05).

CONCLUSIONS

In Chile, patients infected with H. pylori have a proportion of CagA-positive strains similar to that reported in developed countries. CagA prevalence was not significantly different in adults and children infected with H. pylori, suggesting that variations in clinical outcome may be related to host immune or environmental factors.