Helicobacter pylori and gastric malignancies

Evaluation of urea breath test as a diagnostic tool for Helicobacter pylori infection in adult dyspeptic patients

In this editorial, we discuss the article in the World Journal of Gastroenterology. The article conducts a meta-analysis of the diagnostic accuracy of the urea breath test (UBT), a non-invasive method for detecting Helicobacter pylori (H. pylori) infection in humans. It is based on radionuclide-labeled urea. Various methods, both invasive and non-invasive, are available for diagnosing H. pylori infection, including endoscopy with biopsy, serology for immunoglobulin titers, stool antigen analysis, and UBT. Several guidelines recommend UBTs as the primary choice for diagnosing H. pylori infection and for reexamining after eradication therapy. It is used to be the first choice non-invasive test due to their high accuracy, specificity, rapid results, and simplicity. Moreover, its performance remains unaffected by the distribution of H. pylori in the stomach, allowing a high flow of patients to be tested. Despite its widespread use, the performance characteristics of UBT have been inconsistently described and remain incompletely defined. There are two UBTs available with Food and Drug Administration approval: The 13C and 14C tests. Both tests are affordable and can provide real-time results. Physicians may prefer the 13C test because it is non-radioactive, compared to 14C which uses a radioactive isotope, especially in young children and pregnant women. Although there was heterogeneity among the studies regarding the diagnostic accuracy of both UBTs, 13C-UBT consistently outperforms the 14C-UBT. This makes the 13C-UBT the preferred diagnostic approach. Furthermore, the provided findings of the meta-analysis emphasize the significance of precise considerations when choosing urea dosage, assessment timing, and measurement techniques for both the 13C-UBT and 14C-UBT, to enhance diagnostic precision.

Role of New Anatomy, Biliopancreatic Reflux, and Helicobacter Pylori Status in Postgastrectomy Stump Cancer

Distal gastrectomy for benign gastroduodenal peptic disease has become rare, but it still represents a widely adopted procedure for advanced and, in some countries, even for early distal gastric cancer. Survival rates following surgery for gastric malignancy are constantly improving, hence the residual mucosa of the gastric stump is exposed for a prolonged period to biliopancreatic reflux and, possibly, to Helicobacter pylori (HP) infection. Biliopancreatic reflux and HP infection are considered responsible for gastritis and metachronous carcinoma in the gastric stump after oncologic surgery. For gastrectomy patients, in addition to eradication treatment for cases that are already HP positive, endoscopic surveillance should also be recommended, for prompt surveillance and detection in the residual mucosa of any metaplastic-atrophic-dysplastic features following surgery.

The G-Protein Coupled Formyl Peptide Receptors and Their Role in the Progression of Digestive Tract Cancer

Chronic inflammation is a causative factor of many cancers, although it originally acts as a protective host response to the loss of tissue homeostasis. Many inflammatory conditions predispose susceptible cells, most of which are of epithelial origin, to neoplastic transformation. There is a close correlation between digestive tract (DT) cancer and chronic inflammation, such as esophageal adenocarcinoma associated with Barrett’s esophagus, helicobacter pylori infection as the cause of stomach cancer, hepatitis leading to liver cirrhosis and subsequent cancer, and colon cancer linking to inflammatory bowel diseases and schistosomiasis. A prominent feature of malignant transformation of DT tract epithelial cells is their adoption of somatic gene mutations resulting in abnormal expression of proteins that endow the cells with unlimited proliferation as well as increased motility and invasive capabilities. Many of these events are mediated by Gi-protein coupled chemoattractant receptors (GPCRs) including formyl peptide receptors (FPRs in human, Fprs in mice). In this article, we review the current understanding of FPRs (Fprs) and their function in DT cancer types as well as their potential as therapeutic targets.

The Use of 13C-Urea Breath Test for Non-Invasive Diagnosis of Helicobacter pylori Infection in Comparison to Endoscopy and Stool Antigen Test

Helicobacter pylori (H. pylori) can cause gastritis, peptic ulcer diseases and gastric carcinoma. Endoscopy as the gold standard method of diagnosis is an invasive procedure that might not be suitable in all scenarios. Therefore, this first study in Jordan aimed to assess the non-invasive ¹³C urea breath test (UBT) and stool antigen test for diagnosis of H. pylori infection and the successfulness of eradication therapy as alternatives for endoscopy. Hence, a total of 30 patients attending the endoscopy units at Alkarak teaching hospital were asked to complete a questionnaire with demographic and clinical data. They were then tested for H. pylori using ¹³C UBT and H. pylori stool antigen before having endoscopy. Another 30 patients who were positive for H. pylori by endoscopy were tested using both tests 6 weeks post eradication therapy. Results showed that the rate of H. pylori detection using endoscopy was 56.7% (17/30). Heartburns (82.3%, p value = 0.019), epigastric pain (88.2%, p value = 0.007) and vomiting (70.5%, p value = 0.02) were the most significant symptoms. Family history of peptic ulcer diseases was significantly associated with an increased risk for having a H. pylori positive result (p value = 0.02). Compared to endoscopy, the sensitivity of ¹³C UBT for the diagnosis of H. pylori was 94.1% (16/17), while it was 76.5% (13/17) for the stool antigen test. The specificity of both tests was equal (76.9%). However, the positive predictive and negative predictive values (84.2% and 90.9%) for ¹³C UBT were higher than those (81.3% and 71.4%) for the stool antigen test. The accuracy of ¹³C UBT was 86.7% compared to 76.7% for the stool antigen test. There was an 87% agreement (20 patients out of 23) between both tests when used to assess success of the eradication therapy. In conclusion, the ¹³C UBT was found to be more sensitive and accurate than the stool antigen test when used for diagnosis; furthermore, it has a comparable outcome to the stool antigen test in assessing the successfulness of the eradication treatment.

Simvastatin improves the eradication rate of Helicobacter pylori: upper Egypt experience

Background:Helicobacter pylori infection is one of the most prevalent chronic bacterial human infections worldwide. Helicobacter pylori colonizes the gastric mucosa and causes persistent gastritis that may progress to gastric cancer. Increased resistance of H. pylori presents a major problem in most countries. Statins, including simvastatin, which are currently used to treat hypercholesterolemia, appear to have potential synergistic role to antibiotics. This study aimed to assess the value of adding simvastatin as adjuvant to standard triple therapy in patients infected with H. pylori.

Methods: This study was conducted on 100 patients diagnosed with H. pylori by the presence of antigen in stools. All patients were randomly subjected either to the standard triple regimen (clarithromycin 500 mg bid + amoxicillin 1 g bid + omeprazole 20 mg bid) (group 1, N=50) or to the standard triple regimen plus simvastatin (clarithromycin 500 mg bid + amoxicillin 1 g bid + omeprazole 20 mg bid + simvastatin 20 mg bid) (group 2, N=50). Both groups were treated for 14 days and eradication of H. pylori was assessed by a stool antigen test 4 weeks after therapy.

Results: Eradication of H. pylori infection was significantly higher in patients treated with the standard triple therapy plus simvastatin (n=41, 82%) than in patients treated with the standard triple therapy (n=31, 62%) (P<0.022).

Conclusion: Simvastatin significantly improves the H. pylori eradication rate.

Early detection of gastric cancer using global, genome-wide and IRF4, ELMO1, CLIP4 and MSC DNA methylation in endoscopic biopsies

Clinically useful molecular tools to triage gastric cancer patients are not currently available. We aimed to develop a molecular tool to predict gastric cancer risk in endoscopy-driven biopsies obtained from high-risk gastric cancer clinics in low resource settings.

We discovered and validated a DNA methylation biomarker panel in endoscopic samples obtained from 362 patients seen between 2004 and 2009 in three high-risk gastric cancer clinics in Lima, Perú, and validated it in 306 samples from the Cancer Genome Atlas project (“TCGA”). Global, epigenome wide and gene-specific DNA methylation analyses were used in a Phase I Biomarker Development Trial to identify a continuous biomarker panel that combines a Global DNA Methylation Index (GDMI) and promoter DNA methylation levels of IRF4, ELMO1, CLIP4 and MSC.

We observed an inverse association between the GDMI and histological progression to gastric cancer, when comparing gastritis patients without metaplasia (mean = 5.74, 95% CI, 4.97−6.50), gastritis patients with metaplasia (mean = 4.81, 95% CI, 3.77−5.84), and gastric cancer cases (mean = 3.38, 95% CI, 2.82−3.94), respectively (p < 0.0001). Promoter methylation of IRF4 (p < 0.0001), ELMO1 (p < 0.0001), CLIP4 (p < 0.0001), and MSC (p < 0.0001), is also associated with increasing severity from gastritis with no metaplasia to gastritis with metaplasia and gastric cancer.

Our findings suggest that IRF4, ELMO1, CLIP4 and MSC promoter methylation coupled with a GDMI>4 are useful molecular tools for gastric cancer risk stratification in endoscopic biopsies.

Different methylation profiles between intestinal and diffuse sporadic gastric carcinogenesis

OBJECTIVE

Gastric cancer (GC) is histologically classified into intestinal type and diffuse type, and diffuse type cancer can be further subdivided into poorly differentiated carcinoma (PDC) and signet ring cell carcinoma (SRCC). Recent evidence suggests that early SRCC is an initial, differentiated form of diffuse GC that may evolve into PDC. This study aimed at identifying the molecular features of epigenetic methylation changes in histologic differentiation status of GC.

METHODS

Included in this study are 149 samples of paraffin-embedded tissues and 115 fresh endoscopically biopsied tissues. Multiple paraffin tissues involving normal (n=22), dysplasias (GDs, n=39), differentiated cancers (DCs, n=35), PDCs (n=33) and SRCCs (n=20) were included as an experimental group. For the validation group, endoscopically biopsied tissues of DCs (n=50), PDCs (n=31), and SRCs (n=34) were analyzed. DNAs, isolated from each group were analyzed to determine the methylation status of 6 genes (GDNF, RORA, MINT25, KLF7, CDH1, LINE-1) using pyrosequencing.

RESULTS

LINE-1 was hypomethylated in GCs compared to normal and GD. GDNF, RORA and MINT25 were more hypermethylated in intestinal type GCs than those of diffuse type GCs, whereas CDH1 showed opposite patterns of methylation. Among diffuse type GCs, SRCCs showed lower level of methylation for GDNF, RORA, MINT25 and KLF7, and higher level for CDH1 compared to PDCs.

CONCLUSIONS

In conclusion, intestinal type of GCs shows different epigenetic methylation profiles compared to the diffuse one. Moreover, SRCCs have different methylation profiles compared with PDCs, suggesting a unique molecular pathway in the gastric carcinogenesis.

Socioeconomic and nutritional factors account for the association of gastric cancer with Amerindian ancestry in a Latin American admixed population

Gastric cancer is one of the most lethal types of cancer and its incidence varies worldwide, with the Andean region of South America showing high incidence rates. We evaluated the genetic structure of the population from Lima (Peru) and performed a case-control genetic association study to test the contribution of African, European, or Native American ancestry to risk for gastric cancer, controlling for the effect of non-genetic factors. A wide set of socioeconomic, dietary, and clinic information was collected for each participant in the study and ancestry was estimated based on 103 ancestry informative markers. Although the urban population from Lima is usually considered as mestizo (i.e., admixed from Africans, Europeans, and Native Americans), we observed a high fraction of Native American ancestry (78.4% for the cases and 74.6% for the controls) and a very low African ancestry (<5%). We determined that higher Native American individual ancestry is associated with gastric cancer, but socioeconomic factors associated both with gastric cancer and Native American ethnicity account for this association. Therefore, the high incidence of gastric cancer in Peru does not seem to be related to susceptibility alleles common in this population. Instead, our result suggests a predominant role for ethnic-associated socioeconomic factors and disparities in access to health services. Since Native Americans are a neglected group in genomic studies, we suggest that the population from Lima and other large cities from Western South America with high Native American ancestry background may be convenient targets for epidemiological studies focused on this ethnic group.

Incidence and clinical features of endoscopic ulcers developing after gastrectomy

AIM: To determine the precise incidence and clinical features of endoscopic ulcers following gastrectomy.

METHODS: A consecutive series of patients who underwent endoscopic examination following gastrectomy between 2005 and 2010 was retrospectively analyzed. A total of 78 patients with endoscopic ulcers and 759 without ulcers following gastrectomy were enrolled. We analyzed differences in patient age, sex, size of the lesions, method of operation, indications for gastric resection, and infection rates of Helicobacter pylori (H. pylori) between the nonulcer and ulcer groups.

RESULTS: The incidence of endoscopic ulcers after gastrectomy was 9.3% and that of marginal ulcers was 8.6%. Ulcers were more common in patients with Billroth II anastomosis and pre-existing conditions for peptic ulcer disease (PUD). Infection rates of H. pyloridid not differ significantly between the two groups. The patients who underwent operations to treat PUD had lower initial levels of hemoglobin and higher rates of hospital admission.

CONCLUSION: H. pylori was not an important factor in ulcerogenesis following gastrectomy. For patients who underwent surgery for PUD, clinical course of marginal ulcers was more severe.

Ex vivo visualization of Helicobacter pylori using an endocytoscopic probe

Observation of microorganisms by endoscopy has been technically difficult. In this study, we tried to visualize bacteria during endoscopic examination to provide a powerful tool for a diagnosis of gastrointestinal infection. We observed the bacterium Helicobacter pylori, cultured ex vivo, using a novel ultra-high "magnified endoscopy" system ("endocytoscopy" prototype, Olympus Medical Systems). Cultures were prepared from gastric mucus obtained from three gastric ulcer patients. H. pylori in the supernatant of the culture medium were observed directly by endocytoscopy. Staphylococcus aureus and red blood cells were used as controls. H. pylori in the culture medium were observed directly by endocytoscopy, and recorded using a video recorder. Live, moving bacteria can be visualized and recorded ex vivo using this new "endocytoscopy" technology.

Gastric stump carcinoma - epidemiology and current concepts in pathogenesis and treatment

AIM

The aim of this article is to review the aetiology, pathology and treatment of gastric stump carcinoma (GSC). GSC is an uncommon tumour; however, the incidence is not declining, so this tumour entity will be encountered in the years to come.

METHODS

The electronic literature search was performed in the MEDLINE database to identify relevant studies concerning epidemiology, prognosis, treatment, aetiology and pathology of GSC. The references reported in these studies were used to complete the literature search.

RESULTS

Patients subjected to distal gastric resection have a 4-7-fold increased risk of developing GSC, which is attributed mainly to gastroduodenal reflux. Denervation during partial gastrectomy may also contribute to the risk of developing GSC. Gastroduodenal ulcers were the main reason for partial gastrectomy. Both ulcer locations have an increased risk of developing GSC after 20 years. In GSC, Helicobacter pylori seems not to be an important risk factor, contrary to primary gastric cancer, because gastroduodenal reflux impairs the growth of Helicobacter pylori.

CONCLUSION

The treatment of choice for GSC should be the total removal of the gastric remnant including at least D2 lymphadenectomy. The pattern of lymph node metastases in GSC may differ from primary gastric cancer, as lymph node metastases have been reported in the jejunal mesentery and the lower mediastinum. Therefore, GSC may require a modified lymphadenectomy to include all important lymph node stations. After radical remnant gastrectomy, GSC has a prognosis not different from primary proximal gastric cancer.

Demonstration and characterization of mutations induced by Helicobacter pylori organisms in gastric epithelial cells

BACKGROUND

Helicobacter pylori gastritis increases gastric cancer risk. Microsatellite instability-type mutations are secondary to deficient DNA mismatch repair. H. pylori gastritis is more frequent in patients with microsatellite instability-positive gastric cancers, and H. pylori organisms independently of inflammation can reduce DNA mismatch repair protein levels, raising the hypothesis that H. pylori organisms might lead to mutagenesis during infection.

MATERIALS AND METHODS

Mutations were detected using a green fluorescent protein reporter vector (pEGFP-CA13). Gastric cancer AGS cells transfected with pEGFP-CA13 were cocultured with H. pylori or Escherichia coli. The numbers of green fluorescent protein (GFP)-positive cells were determined, and GFP, hMSH2, and hMLH1 protein levels were measured by Western blot. The effect of H. pylori on CpG methylation status of hMLH1 was determined by methylation-specific polymerase chain reaction.

RESULTS

GFP levels and GFP-positive cell numbers in AGS cells cocultured with H. pylori significantly increased, as the levels of hMLH1 and hMSH2 dropped. H. pylori cocultures induced low-level CpG methylation of the hMLH1 promoter. Sequence analysis of cells cocultured with H. pylori showed an increased number of frameshift mutations and point mutations as compared to cells not cocultured with H. pylori (p = .03 and p = .001, respectively).

CONCLUSIONS

This is the first report showing that H. pylori bacteria may lead to accumulation of genomic mutations, independently of underlying inflammation. This is associated with reduced DNA mismatch repair, and is at least in part associated with CpG methylation of the hMLH1 promoter. These data support the notion that H. pylori-induced mutations and epigenetic alterations in gastric epithelial cells during chronic gastritis may contribute to an increased risk of gastric cancer associated with H. pylori infection.

Linfomas em pacientes com a forma hepatoesplênica da esquistossomose mansônica

RACIONAL: Cada vez mais se estabelece a correlação entre agentes infecciosos e doenças linfoproliferativas, sobretudo vírus e bactérias, através da ativação de linfócitos. OBJETIVO: Descrever 6 novos casos, de uma série de 254 pacientes (2,36%) com esquistossomose mansônica na forma hepatoesplênica. CASUÍSTICA E MÉTODOS: São descritos 6 pacientes, dentre os 254 portadores de esquistossomose mansônica na forma hepatoesplênica, acompanhados nos últimos 13 anos no Serviço de Cirurgia Geral do Hospital das Clínicas da Universidade Federal de Pernambuco, Recife, PE. RESULTADOS: Todos os seis casos ocorreram em mulheres. Os exames histopatológicos evidenciaram dois casos de linfomas de zona marginal esplênica, um de linfoma de grandes células com imunoblastos, um de linfoma difuso de grandes células, um de linfoma maligno de grandes células não clivadas, e um outro caso de doença de Hodgkin. Metade das seis pacientes evoluiu para o óbito entre 4 a 15 meses após o diagnóstico. As outras três persistem em acompanhamento no Serviço de Oncologia da mesma instituição. CONCLUSÃO: A incidência de linfoma nos 254 pacientes acompanhados foi de 2,36%. Pretende-se chamar a atenção para a ocorrência de linfomas nos baços de pacientes com esquistossomose mansônica, na forma hepatoesplênica.

Helicobacter pylori infection is not associated with an increased hemorrhagic risk in patients in the intensive care unit

Introduction

The potential role of Helicobacter pylori in acute stress ulcer in patients in an intensive care unit (ICU) is controversial. The aim of this study was to determine the frequency of H. pylori infection in ICU patients by antigen detection on rectal swabs, and to analyze the potential relationship between the presence of H. pylori and the risk of digestive gastrointestinal bleeding.

Methods

In this prospective, multicenter, epidemiological study, the inclusion criteria were as follows: patients admitted to the 12 participating ICU for at least two days, who were free of hemorrhagic shock and did not receive more than four units of red blood cells during the day before or the first 48 hours after admission to the ICU. Rectal swabs were obtained within the first 24 hours of admission to the ICU and were tested for H. pylori antigens with the ImmunoCard STAT! HpSA kit. The following events were analyzed according to H. pylori status: gastrointestinal bleeding, unexplained decline in hematocrit, and the number of red cell transfusions.

Results

The study involved 1,776 patients. Forty-nine patients (2.8%) had clinical evidence of upper digestive bleeding. Esophagogastroduodenoscopy was performed in 7.6% of patients. Five hundred patients (28.2%) required blood transfusion. H. pylori antigen was detected in 6.3% of patients (95% confidence interval 5.2 to 7.5). H. pylori antigen positivity was associated with female sex (p < 0.05) and with a higher Simplified Acute Physiology Score II (SAPS II; p < 0.05). H. pylori antigen status was not associated with the use of fiber-optic gastroscopy, the need for red cell transfusions, or the number of red cell units infused.

Conclusion

This large study reported a small percentage of H. pylori infection detected with rectal swab sampling in ICU patients and showed that the patients infected with H. pylori had no additional risk of gastrointestinal bleeding. Thus H. pylori does not seem to have a major role in the pathogenesis of acute stress ulcer in ICU patients.

Interaction between Helicobacter pylori infection and untreated coeliac disease on gastric histological pattern

OBJECTIVE

Helicobacter pylori infection is the major agent of gastric damage. Coeliac disease may affect the morphology and function of the entire gastrointestinal tract from the stomach to the colon. The aim of this study was to assess the gastric histological pattern in patients with H. pylori and untreated coeliac disease.

MATERIAL AND METHODS

We retrospectively enrolled 183 H. pylori-positive patients with (85, group A) and without (98, group B) untreated coeliac disease. The groups were similar for age, gender and smoking habit, and all the patients came from the same geographical area. Histological evaluation of gastric pattern was performed on 4 biopsies (2 in the antrum, 2 in the corpus). Gastric damage was classified according to the modified Sydney System. Diagnosis of H. pylori infection was based on positivity to histology. The chi-square test was used to assess differences between groups. A p-value <0.05 was considered significant.

RESULTS

Group A showed a significantly higher prevalence of follicular gastritis than group B (23.5% versus 12.2%, p=0.045). A significantly lower prevalence of atrophic gastritis was observed in group A compared with that in group B (6% versus 22.5%, p=0.002). The prevalence of chronic superficial gastritis, activity degree and intestinal metaplasia was similar between the two groups.

CONCLUSIONS

In patients with H. pylori infection, untreated coeliac disease could represent a risk factor for follicular gastritis and is associated with a lower prevalence of atrophic gastritis. The complex interaction between H. pylori and untreated coeliac disease on Th-1/Th-2 balance in the gastric mucosa could explain these results.