Pathogenesis of Helicobacter pylori infection

Evaluation of the Inflammatory Response After Eradication of Helicobacter pylori in Patients With Familial Mediterranean Fever

PURPOSE

Evaluation of the inflammatory response after Helicobacter pylori (Hp) eradication in patients with Familial Mediterranean Fever (FMF) during the non-attack period and determining whether there is a change in the ongoing inflammation during the non-attack period.

MATERIALS AND METHODS

Sixty-four patients, who have not been eradicated for Hp in the last 2 years, diagnosed with FMF, and evaluated in the non-attack period, were included in the study. Hp eradication therapy was administered to patients who were found to be Hp-positive. C-reactive protein (CRP), high-sensitive C-reactive protein (hs-CRP), interleukin-6, interleukin-8, tumor necrosis factor-alpha, and serum amyloid A values were compared between the groups before and after eradication.

RESULTS

CRP and hs-CRP levels were found to be statistically higher in the FMF group than in the control group. A statistically significant decrease was found in the values of CRP and hs-CRP, in the number of patients with attacks, and in attack frequency after eradication in the Infected Patients compared to the values before eradication.

CONCLUSIONS

We determined a decrease in CRP and hs-CRP values, the number of patients with attacks, and attack frequency with the eradication of Infected Patients. In patients with FMF, in whom it has been proven by different studies that the inflammation continues during the non-attack period, it may be recommended to investigate the presence of Hp infection, which is thought to contribute to this inflammation and to give Hp eradication therapy to patients who are found positive to reduce the development of secondary complications caused by chronic inflammation.

Association of Helicobacter pylori infection with coronary artery disease: is it an independent risk factor?

BACKGROUND

Coronary artery disease (CAD) is a dilemma and a serious cause of morbidity and mortality worldwide. Since CAD has been seen in people without the conventional risk factors like smoking, diabetes, and hypertension, the infectious theory being a risk factor has arisen.

MAIN BODY

Helicobacter pylori (HP) infection is the most common infection affecting the vast majority of the population worldwide. HP grows in the gastrointestinal tract (GIT) and responsible for chronic gastritis, peptic ulcer, gastric adenocarcinoma, and gastric lymphoma. A review of medical literature mainly PubMed has revealed several studies reporting that HP pathogenesis extends beyond the GIT to be a predisposing factor for atherosclerosis, dyslipidemia, thrombosis, and CAD. However, it remains a controversial issue that warrants extensive research.

CONCLUSION

This article gives insight into the diversity of opinions, evidence, and theories regarding the association between HP infection and CAD. The idea that CAD may be managed with antibiotics in certain patients seems to be creative and inspiring. More research is mandatory to either verify or reject this proposed correlation with strong scientific evidence and also to demonstrate the implications of the results on CAD management and outcome.

High correlation of babA 2-positive strains of Helicobacter pylori with the presence of gastric cancer

Helicobacter pylori (H. pylori) is a Gram-negative bacterium that is well known in the involvement of chronic inflammation in the gastric mucosa of the human stomach. Several studies have investigated the possible role of H. pylori presence in different gastroduodenal disorders with conflicting results. This study aimed to further investigate such a field. Helicobacter pylori strains were cultured from 160 patients (mean age of 42 years; range 15-75; 90 were male, and 70 were female) [40 gastric cancer (GC), 55 duodenal ulcer (DU) and 65 non-ulcer dyspepsia (NUD)]. In this study, allelic variants of iceA 1, iceA 2 and babA 2 were identified by polymerase chain reaction. The overall prevalence of babA 2 gene was 40.6% (65/160). The prevalence of babA 2 gene was 95% with gastric cancer, 18.1% with duodenal ulcer and 26.1% with non ulcer dyspepsia, respectively. The prevalence of babA 2 in GC patients was significantly higher as compared to either NUD or UD patients (P = 0.0004), while no statistical significance was found between the latter two patient groups. Our study finds that babA 2 and iceA 1 genes are more prevalent in GC compared to either NUD or DU patients in Iran.

The prevalence of Helicobacter pylori in obese subjects

BACKGROUND

Obesity and Helicobacter pylori (H. pylori) are important because of the problems they lead and their frequency of occurrence. In this study, we aimed to find out the prevalence of H. pylori infection and the relationship between obesity and H. pylori in obese and normal weight subjects.

METHODS

A total of 214 subjects were (103 obese (71 male, 32 female), and 111 control (60 male, 51 female)) admitted to the study. Body mass indices (BMI) of all subjects were calculated and fasting plasma glucose (FPG), blood lipids and H. pylori positivity were studied.

RESULTS

The mean age of the obese and control groups was (24.3+/-5.4 yr), and (25.5+/-5.4 yr), and the mean BMI was (34.6+/-3.7 kg/m(2)), and (24.2+/-2.8 kg/m(2)) respectively. We didn't observe a significant difference between FPG, Total-C, and LDL-C levels of the obese and control groups, however there was a difference between gastrointestinal symptoms, sistolic and diastolic BP, TG and HDL-C levels. H. pylori prevalence was determined at 57.2% (59/103) in obese group and 27.0% (30/111) in control group (odds ratio=2.11; 95% CI, 1.49-3.00; p<0.001) and 41.5% (89/214) in all study population.

CONCLUSION

In our study, we determined that prevalence of H. pylori increased in subjects with obesity. We consider that obesity can be a risk factor for H. pylori infection. However, further studies evaluating more subjects are required.

Prevalence of virulence-associated genotypes of Helicobacter pylori and correlation with severity of gastric pathology in patients from western Sicily, Italy

In a bacterium like Helicobacter pylori, which is characterized by a recombinant population structure, the associated presence of genes encoding virulence factors might be considered an expression of a selective advantage conferred to strains with certain genotypes and, therefore, a potentially useful tool for predicting the clinical outcome of infections. However, differences in the geographical and ethnic prevalence of the H. pylori virulence-associated genotypes can affect their clinical predictive value and need to be considered in advance. In this study we carried out such an evaluation in a group of patients living in Sicily, the largest and most populous island in the Mediterranean Sea. cagA, vacA, babA2, hopQ, oipA, sabA, and hopZ were the H. pylori virulence-associated genes assayed; their presence, expression status or allelic homologs were detected in H. pylori DNA samples and/or isolated strains, obtained by gastric biopsy from 90 Sicilian patients with chronic gastritis, inactive (n = 37), active (n = 26), or active with peptic ulcer (n = 27). Genotypes cagA (+), vacAs1, vacAm1, babA2 (+), and hopQ I, I/II were identified in 51.8, 80.4, 35.2, 47.3, and 67.7% of the different samples respectively. Only these genotypes were associated with each other and with the active form of chronic gastritis, irrespective of the presence of a peptic ulcer. In our isolates their prevalence was more similar to values observed in the north of Italy and France than to those observed in Spain or other Mediterranean countries that are closer and climatically more similar to western Sicily.

Patients with duodenal ulcer have lower levels of serum cholesterol compared to other dyspeptic patients independently of Helicobacter pylori status

OBJECTIVE

The association between Helicobacter pylori (H. pylori) infection and serum lipid profile is still controversial. The aim of this study was to determine any possible relationship between H. pylori infection and the lipid profile of patients with upper gastrointestinal symptoms.

MATERIAL AND METHODS

Consecutively selected 20-70 year-old dyspeptic patients who had undergone esophagogastroduodenoscopy were evaluated for H. pylori infection using both the CLO test and Giemsa staining. Serum total cholesterol (C), HDL-C, LDL-C, apo-A1, apo-B and triglyceride levels were measured.

RESULTS

A total of 137 patients (median age 52.0 years) were studied. Total cholesterol levels were lower in H. pylori-infected patients than in H. pylori-negative patients (mean +/- SEM: 199.3 +/- 5.9 versus 212.6 +/- 4.6 mg/dl, p = 0.08). Patients with duodenal ulcer (DU) had significantly lower levels of all measured lipidemic parameters including cholesterol, with the exception of triglycerides, in comparison with either H. pylori-positive or -negative dyspeptic patients (cholesterol: 177.6 +/- 6.5 versus 214.6 +/- 4.2 mg/dl, p < 0.0001). However, there was no difference in the total cholesterol/HDL-C ratio between DU patients and the rest of the dyspeptic patients.

CONCLUSIONS

Among H. pylori-positive and H. pylori-negative patients there was no difference in lipid profile apart from a trend towards total cholesterol levels being lower in H. pylori-positive patients. However, cholesterol, HDL-C, LDL-C, apo-A and apo-B were all decreased in DU patients even though this reduction did not result in a fall in the total cholesterol/HDL-C ratio. The etiologic factor differentiating the lipid profiles among dyspeptics only in H. pylori-positive patients carrying a DU could be dietetic, microbial, genetic or a combination of all three.

[Comparison of three diagnostic methods to confirm Helicobacter pylori infection]

INTRODUCTION

Helicobacterpylori induces gastric inflammation in host and such gastritis increases the risk of gastric and duodenal ulceration as well as adenocarcinoma. Because peptic ulcer disease is the major cause of morbidity, accurate diagnosis of H. pylori infection is very important. Unfortunately, there is no gold standard among diagnostic tests for Helicobacter infections. If gastroscopy is performed, histopathology and urease test are the most often used. Still, culturing of this bacterium is essential for drug susceptibility testing and analysis of virulence factors.

OBJECTIVE

The aim of this study was to compare three diagnostic procedures--histopathology, urease test and culture, which are used to verify H. pylori infection.

METHOD

Three pairs of gastric mucosal biopsy specimens were collected from each of 28 dyspeptic patients undergoing endoscopy. Nineteen patients were not pretreated with antibiotics, while nine had received eradication therapy earlier. One pair of biopsy specimens was used for histopathologic examination, the second for urease test and the third was simultaneously cultured on nonselective and selective solid media. Isolate was identified as H. pylori on the basis of colony morphology, morphological properties and biochemical tests.

RESULTS

In 14 out of 28 patients, H. pylori infection was confirmed on the basis of results of all diagnostic procedures. The concordance of these three methods was very good, because the results of histopathology, urease test and culture corresponded in 26 from 28 patients.

CONCLUSION

The conclusion of our study is that culture, as the method with high degree of concordance with other two procedures and the only that can give information on drug susceptibility of Helicobacter, is recommended for diagnosis of Helicobacter pylori infection along with histopathology and urease test.

Prevalence of Helicobacter pylori cagA, iceA and babA2 alleles in Brazilian patients with upper gastrointestinal diseases

Helicobacter pylori is an important human pathogen associated with gastrointestinal diseases such as gastritis, gastric and duodenal ulcer (peptic ulcer disease, PUD), and gastric cancer. A number of pathogenic factors have been described for this bacterium, and some of them have been proposed as markers for the prediction of the clinical outcome. However, with the exception of the cag and vacA status, there is no universal consensus regarding the importance of the other virulence factors. Therefore, the aim of this study was to investigate the status of H. pylori strains regarding the babA and iceA alleles, as well as the cagA genotype, to reveal any association between these genotypes and clinical outcomes in Brazilian patients. The great majority (92.6%) of the strains were typed as iceA1, while 40.4% were found to possess the babA2 allele. The cagA gene was detected in 73.4% of the strains. The iceA2 and cagA genotypes were associated with PUD, while iceA1 was negatively correlated with PUD. However, considering the high percentage of strains typed as iceA1, these associations must be treated with caution. No clinical entity was associated with the babA2 allele. These results suggest that iceA1 is not a good marker for the diseases associated with H. pylori infection in Brazil. Further studies are needed in order to elucidate the relevance of the babA status, because other studies performed in Brazil have associated the babA2 allele with clinical outcomes. These results also indicate the existence of regional differences in the H. pylori genotypes and their association with clinical outcomes.

Helicobacter pylori-associated immune thrombocytopenia

Idiopatic thrombocytopenic purpura (ITP), a disorder characterized by autoantibody-mediated platelet destruction, may be primary or secondary to various illnesses including lymphoproliferative, autoimmune, or infectious diseases. There are increasing data on the association between Helicobacter pylori infection and idiopathic thrombocytopenic purpura and the significant increase in platelet count after bacterial eradication. The aim of this review is to consider the studies so far published on Helicobacter pylori infection and idiopathic thrombocytopenic purpura in order to evaluate a possible pathogenic correlation between these two conditions. A review of the literature data show that Helicobacter pylori eradication in patients with idiopathic thrombocytopenic purpura is effective in increasing platelet count in approximately half of the cases. However, since the studies so far published are few, sometimes controversial and involve small series of patients, further controlled studies on larger numbers of patients with longer follow-up are needed to confirm these preliminary findings.

Helicobacter pylori protein oxidation influences the colonization process

Dsb proteins control the formation and rearrangement of disulfide bonds during the folding of membrane and exported proteins. Here we examined the role of DsbI protein in Helicobacter pylori pathogenesis and demonstrated that a dsbI mutant impaired in disulfide bond formation revealed a greatly reduced ability to colonize mice gastric mucosa.

Evaluation of seaFAST, a rapid fluorescent in situ hybridization test, for detection of Helicobacter pylori and resistance to clarithromycin in paraffin-embedded biopsy sections

A commercially available rapid fluorescent in situ hybridization (FISH) test, (seaFAST H. pylori Combi-Kit; SeaPro Theranostics International, Lelystad, The Netherlands) was used to simultaneously detect the presence of Helicobacter pylori and determine clarithromycin susceptibility in paraffin-embedded biopsy sections. The FISH method was found to be 97% sensitive, 94% specific for the detection of H. pylori and comparable to agar dilution for the detection of resistance to clarithromycin.

Detection of Helicobacter pylori-specific genes in the oral yeast

BACKGROUND

Until today, human stomach is the only recognized habitat of Helicobacter pylori. However, recruitment of DNA-based methods has made possible the detection of H. pylori in water and oral cavity, thus suggesting fecal-oral and oral-oral routes for transmission of H. pylori, respectively. In this study, yeast has been proposed as a common vector for transmission of H. pylori. Thus designed primers were recruited to target 16S rDNA and cagA genes in the oral yeasts by PCR.

MATERIALS AND METHODS

Eighteen yeasts were examined microscopically for the presence of bacterial-like bodies. DNAs were extracted from oral yeasts using phenol-chloroform method. Amplification conditions were optimized as 33 cycles and annealing temperatures of 63 degrees C for 16S rDNA and 51 degrees C and 52 degrees C for cagA gene which was targeted in two steps. DNAs of H. pylori and Saccharomyces cerevisiae were used as controls. Polymerase chain reaction (PCR) products of two genes from one yeast and from H. pylori were cloned in pCAP and subsequently subcloned in pSK+ and were sequenced.

RESULTS

Bacterial-like bodies were observed in all oral yeasts. The amplified products of 16S rDNA from all oral yeasts were homologous in size with those of H. pylori. Fifteen out of eighteen (83%) yeasts contained cagA gene, homologous to H. pylori. CagA was not amplified from three yeasts and S. cerevisiae. Analysis of the sequenced products of 16S rDNA and cagA from one oral yeast showed 98% homology with those of H. pylori.

CONCLUSIONS

The presence of H. pylori inside the yeast was indicated by light microscopy and PCR. It appears that yeasts, which are abundant in nature and thrive the mucosal surfaces of human, might serve as reservoirs and vehicles of H. pylori.

[Pathogenesis of Helicobacter pylori infection--bacterium and host relationship]

Helicobacter pylori (H. pylori) colonizes the gastric mucosa of a half of the mankind. Duodenal ulcer is found in 15-25%, gastric ulcer in 13%, while gastric adenocarcinoma develops in 1% of all infected individuals. Pathogenesis of H. pylori infection is related to the virulence factors of the bacterium, environmental (dietary habits, hygiene, stress) and host factors (age, sex, blood type). Colonization of the gastric mucosa is related to the motility of the bacterium, presence of lipopolysaccharide (LPS) and various bacterial enzymes. Gastric mucosal injury is the result of H. pylori LPS, vacuolization cytotoxin (vacA), cytotoxin associated protein (cagA), heat shock proteins and factors responsible for neutrophil chemotaxis and activity. H. pylori colonizes the gastric mucosa and zones of ectopic gastric epithelium. H. pylori infection is transmitted via oral-oral, fecal-oral and iatrogenic way (during endoscopy). Higher prevalence of the infection is associated with lower socioeconomic level, lack of drinking water, and living in a community. Acute H. pylori gastritis is superficial pangastritis progressing into the chronic phase after 7-10 days. Gastric mucosal atrophy and intestinal metaplasia can develop during the course of H. pylori infection. Clearly defined factors that influence the outcome of H. pylori infection include bacterial strain, distribution of gastritis, acid secretion and gastric mucosal atrophy.

Helicobacter pylori infection and immune thrombocytopenic purpura: an update

Data are accumulating on the association between Helicobacter pylori infection and idiopathic thrombocytopenic purpura (ITP) and the significant increase in platelet count after bacterial eradication. The aim of this review was to consider the studies so far published on H. pylori infection and ITP in order to evaluate a possible correlation between these two conditions. A review of the literature showed that 278 out of the 482 ITP patients investigated (58%) were positive for H. pylori infection and that the bacterium was eradicated in 88% of cases. Eradication therapy was accompanied by a complete or partial platelet response in approximately half the cases. Overall, these data show that H. pylori eradication in patients with ITP is effective in increasing platelet count. However, because the studies so far published are few, are sometimes controversial and involve small series of patients, further studies on larger numbers of patients with longer follow-up are needed to confirm these preliminary findings.

Establishment of mouse models with long-term infection of H. pylori

AIM: To develop a mouse model with long-term infection of H. pylori.

METHODS: Each mouse was inoculated with H. pylori Sydney strain 1 (SS1). Noninfected control mice and infected mice were killed at 4, 12 and 24 wk after H. pylori infection. A piece of gastric mucosa obtained from the posterior wall of the antrum of each mouse was used for culture of H. pylori, rapid urease testing and histopathological detection. Serum was obtained to measure the IgG antibody level to H. pylori.

RESULTS: After 4 wk of infection, the H. pylori was cultured from 6 of 7 infected Babl/c mice and 5 of 7 the H. pylori-infected C57BL/6 mice. After 12 and 24 wk of infection, all of 7 infected Babl/c and 6 of 7 the H. pylori-infected C57BL/6 mice showed the positive results. At the different wk, the rapid urease test results were consistent with the H. pylori culture test. At 12 wk after inoculation, chronic inflammation was observed in the pyloric mucosa by histopathological examination. At 24 wk after inoculation, lymphoid follicles were especially conspicuous in the submucosa, and they were also found in the deep portion of the mucosa.

CONCLUSION: H. pylori SS1 can colonize easily in the glandular stomach mucosa of mouse, and the histopathological changes are similar to those of humans with H. pylori infection.