INTRODUCTION:

Screening tests for gastrointestinal diseases acceptable for population with a high sensitivity and high specificity can now be offered by clinical laboratories. This paper summarizes major recent advances in this area of laboratory medicine.

METHODS:

Relevant articles published within the last 5 years in the NLM (National Library of Medicine) PubMed - Medline database covering the three gastrointestinal diseases - colorectal cancer, coeliac disease, and atrophic gastritis were included for this overview.

RESULTS:

In Europe, colorectal cancer (CRCA) is the second most frequent malignant disease. Quantitative immunochemical analysis of the stool for haemoglobin provides the best screening test to date, with both sensitivity and specificity approaching 95%. Even though coeliac disease (CD) affects approximately 1% of the general population, it remains largely unrecognised. Recommended methods for screening currently involve the detection of IgA and IgG antibodies against tissue transglutaminase and deamidated gliadin peptide. Evaluations of screening are now discussed for other diseases of the gastrointestinal tract - such as chronic atrophic gastritis (CAG), and inflammatory bowel disease (IBD). Detection of infection by Helicobacter pylori and stomach-specific plasmatic biomarkers, especially pepsinogen I/II ratio, could help with the prevention of gastric carcinomas. The use of faecal calprotectin as a screening test could substantially reduce the number of invasive methods necessary for the diagnostic work-up of patients with IBD.

CONCLUSIONS:

Screening tests for CRCA and CD have been used worldwide for many years. Screening strategies for gastrointestinal diseases are suggested in the text, based on recent basic science, clinical papers as well as our own experience.

To investigate the influence of the CagA diversity in Helicobacter pylori (H. pylori) strains from Colombia on the host cell biology.Eighty-four H. pylori-cagA positive strains with different Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs patterns, isolated from patients with gastritis (n = 17), atrophic gastritis (n = 17), duodenal ulcer (n = 16), intestinal metaplasia (n = 16) and gastric cancer (n = 18), were included. To determine the integrity of the cag pathogenicity island (cagPAI) we evaluated the presence of cagA, cagT, cagE, and cag10 genes by polymerase chain reaction. AGS gastric epithelial cells were infected with each strain and assayed for translocation and tyrosine phosphorylation of CagA by western blot, secretion of interleukin-8 (IL-8) by enzyme-linked immuno sorbent assay after taking supernatants from cocultures and cell elongation induction. For cell elongation quantification, coculture photographs were taken and the proportion of "hummingbird" cells (> 15 μm) was determined.Overall 72% (60/84) of the strains were found to harbor a functional cagPAI. Levels of phosphorylated CagA were significantly higher for isolates from duodenal ulcer than the ones in strains from gastritis, atrophic gastritis, intestinal metaplasia and gastric cancer (49.1% ± 23.1% vs 21.1% ± 19.5%, P < 0.02; 49.1% ± 23.1% vs 26.2% ± 14.8%, P < 0.045; 49.1% ± 23.1% vs 21.5% ± 19.5%, P < 0.043 and 49.1% ± 23.1% vs 29.5% ± 27.1%, P < 0.047 respectively). We observed variable IL-8 expression levels ranging from 0 to 810 pg/mL and from 8.8 to 1442 pg/mL at 6 h and 30 h post-infection, respectively. cagPAI-defective strains did not induce detectable levels of IL-8 at 6 h post-infection. At 30 h post-infection all strains induced IL-8 expression in AGS cells, although cagPAI-defective strains induced significantly lower levels of IL-8 than strains with a functional cagPAI (57.1 ± 56.6 pg/mL vs 513.6 ± 338.6 pg/mL, P < 0.0001). We did not observe differences in the extent of cell elongation induction between strains with a functional or a defective cagPAI in 6 h cocultures. At 24 h post infection strains with functional cagPAI showed high diversity in the extent of hummingbird phenotype induction ranging from 7% to 34%. cagPAI defective strains induced significantly lower levels of elongation than strains with functional cagPAI with one or more than one EPIYA-C motif (15.1% ± 5.2% vs 18.9% ± 4.7%, P < 0.03; and 15.1% ± 5.2% vs 20.0% ± 5.1%, P < 0.003 respectively). No differences were observed in cellular elongation induction or IL-8 expression among H. pylori strains bearing one and more than one EPIYA-C motifs, neither at 6 h nor at 24 h of coculture. There were no associations between the levels of induction of cell elongation or IL-8 expression and number of EPIYA motifs or pathology.The present work describes a lack of association between H. pylori CagA protein EPIYA motifs variations from Colombian isolates and disease-associated cellular responses.

Helicobacter pylori-infection associated gastritis is known to be a significant risk factor of gastric cancer. Serum levels of Gastrin-17 and Pepsinogen1which are respectively biomarkers of gastric antral and corpus mucosal activity are well known parameters of atrophic gastritis.To determine the prevalence of Helicobacter pylori and atrophic gastritis amongst dyspeptic patients and to compare the production of PGI and G-17 in the various atrophic stages.A total of 139 dyspeptic patients aged 46.68±15.50 years [females 106 aged47.23±15.51years, males 33 aged 44.48±14.62] were included during the one year period, March 2008-april 2009 at the district hospital Tombel. The degree of atrophy was determined by the levels of serum pepsinogen1, and gastrin-17 and the presence of Helicobacter pylori antibodies detected by an enzyme immunoassay.The prevalence of Helicobacter pylori was 79.82% and that for atrophic gastritis was 6.6%. A decrease in mean serum levels of gastin-17 along with increasing antral atrophy was observed; the mean serum levels of pepsinogen1 were reduced during progression of corpus atrophy.A weak reverse correlation(r =-0.036) was found between Gastrin-17 and Helicobacter pylori antibodies.

Achlorhydria caused by e.g. atrophic gastritis allows for bacterial overgrowth, which induces chronic inflammation and damage to the mucosal cells of infected individuals driving gastric malignancies and cancer. Enterococcus faecalis (E. faecalis) can colonize achlohydric stomachs and we therefore wanted to study the impact of E. faecalis infection on inflammatory response, reactive oxygen species (ROS) formation, mitochondrial respiration, and mitochondrial genetic stability in gastric mucosal cells.To separate the changes induced by bacteria from those of the inflammatory cells we established an in vitro E. faecalis infection model system using the gastric carcinoma cell line MKN74. Total ROS and superoxide was measured by fluorescence microscopy. Cellular oxygen consumption was characterized non-invasively using XF24 microplate based respirometry. Gene expression was examined by microarray, and response pathways were identified by Gene Set Analysis (GSA). Selected gene transcripts were verified by quantitative real-time polymerase chain reaction (qRT-PCR). Mitochondrial mutations were determined by sequencing.Infection of MKN74 cells with E. faecalis induced intracellular ROS production through a pathway independent of oxidative phosphorylation (oxphos). Furthermore, E. faecalis infection induced mitochondrial DNA instability. Following infection, genes coding for inflammatory response proteins were transcriptionally up-regulated while DNA damage repair and cell cycle control genes were down-regulated. Cell growth slowed down when infected with viable E. faecalis and responded in a dose dependent manner to E. faecalis lysate.Infection by E. faecalis induced an oxphos-independent intracellular ROS response and damaged the mitochondrial genome in gastric cell culture. Finally the bacteria induced an NF-κB inflammatory response as well as impaired DNA damage response and cell cycle control gene expression. TRANSCRIPT PROFILING: Array Express accession number E-MEXP-3496.

The role of putative preneoplastic enterochromaffin-like cell lesions, either hyperplastic or dysplastic, in the genesis of type 1 enterochromaffin-like cell neuroendocrine tumors associated with type A chronic atrophic gastritis, their actual neoplastic risk, and their precise histogenetic mechanism deserve further clarification by specific histopathologic studies coupled with patient follow-up. A total of 100 patients with severe type A chronic atrophic gastritis, enterochromaffin-like cell hyperplasia, and antral G-cell hyperplasia were endoscopically and histologically followed up for a median of 90.1 months (total of 9118 person-months). Preneoplastic enterochromaffin-like cell lesions and newly developed neuroendocrine tumors were investigated histologically and histochemically, in parallel with enterochromaffin-like cell lesions found in nontumor mucosa of another 32 well-characterized and previously reported type 1 neuroendocrine tumors. Both neuroendocrine and nonneuroendocrine mucosa changes were analyzed and statistically evaluated. During follow-up, 7 of 100 patients developed neuroendocrine tumors: 5 were in a group of 20 cases with previous enterochromaffin-like cell dysplasia and 2 were among 80 cases showing only enterochromaffin-like cell hyperplasia throughout the study (hazard ratio, 20.7; P < .001). The severity of enterochromaffin-like cell hyperplasia at first biopsy, with special reference to linear hyperplasia with 6 chains or more per linear millimeter, also increased the risk of neuroendocrine tumor development during follow-up (hazard ratio, 13.0; P < .001). Enterochromaffin-like cell microinvasive dysplastic lesions arising at the epithelial renewal zone level, in connection with immature proliferating mucous-neck cells, were found to be linked to early intramucosal neuroendocrine tumor histogenesis. Both enterochromaffin-like cell dysplasia and severe hyperplasia indicate increased risk of neuroendocrine tumor development in type A chronic atrophic gastritis with hypergastrinemia/G-cell hyperplasia.

GOALS:: To evaluate the prevalence of functional dyspepsia (FD) and its risk factors.

BACKGROUND::

FD is a common disorder, but its negative influences greatly affect the quality of life. The predictive factors of FD are still ambiguous. STUDY:: A total of 3399 participants underwent screening gastroscopy at one of 7 nationwide health care centers in Korea and who completed a questionnaire. Atrophic gastritis was defined by gastroscopy. Serologic Helicobacter pylori immunoglobulin G antibody was measured by enzyme-linked immunosorbent assay.

RESULTS::

Of the 3399 participants who did not have organic diseases, 694 (20.4%) had dyspeptic symptoms such as epigastric pain/soreness or postprandial discomfort. Among the 694 participants, atrophic gastritis and positive H. pylori serology were found in 282 (40.6%) and 422 (60.8%), respectively; these proportions were not different from the remaining asymptomatic subjects. Multivariate analysis showed that having relatives with gastric cancer [odds ratio (OR), 1.35; 95% confidence interval (CI), 1.01-1.81], education below college (OR, 1.32; 95% CI, 1.06-1.64), and high-salt diet (OR, 1.33; 95% CI, 1.05-1.68) were associated with FD symptoms.

CONCLUSIONS::

FD symptoms were frequently found in the health check-up subjects. Relatives of gastric cancer, education below college, and high-salt diet were risk factors of FD, suggesting that FD is a multifactorial disease.

BACKGROUND:

MicroRNAs (miRNAs) have been implicated in various human diseases. Single nucleotide polymorphisms (SNPs) in inflammation-related miRNA may play an important role in Helicobacter pylori (H. pylori)-induced gastric lesions. To evaluate the associations between miRNA SNPs, H. pylori and gastric lesions, a population-based study was conducted in Linqu County, China.

METHOD

OLOGY

PRINCIPAL FINDINGS:

Based on serum miRNA array conducted in this population, two SNP loci (miR-146a rs2910164: G>C and miR-27a rs895819: T>C) were determined by polymerase chain reaction-restriction fragment length polymorphism in 2,380 participants with diverse gastric lesions. Using participants with superficial gastritis and mild chronic atrophic gastritis as the reference group, we found that rs2910164 CC carriers had a significantly increased risk of intestinal metaplasia [adjusted odds ratio (OR), 1.42; 95% confidence interval (CI), 1.03-1.97] and dysplasia (OR, 1.54; 95% CI, 1.05-2.25) compared to GG carriers, whereas no significant association was observed for rs895819. Stratified analysis by H. pylori infection indicated that rs2910164 C allele was associated with an increased risk of intestinal metaplasia and dysplasia only among individuals infected with H. pylori (CC vs. GG: OR, 1.53; 95% CI, 1.12-2.08, P for trend = 0.004). Participants who simultaneously carried variant alleles and H. pylori infection were more likely to develop intestinal metaplasia and dysplasia, although the interaction between genetic variants and H. pylori infection was not significant (P for interaction = 0.35 for rs2910164 and 0.92 for rs895819).

CONCLUSIONS

SIGNIFICANCE:

These findings suggest that miR-146a rs2910164 polymorphism may contribute to the evolution of H. pylori-associated gastric lesions in this high-risk population.

BACKGROUND:

Helicobacter pylori is a major cause of chronic gastritis and an established risk factor for gastric adenocarcinoma. This bacterium also exhibits an extraordinarily high genetic diversity.

METHODS:

The genetic diversity of H. pylori strains from Venezuelan patients with chronic gastritis was evaluated by PCR-typing of vacA, cagA, iceA, and babA2 virulence-associated genes using DNA extracted directly from biopsies. The nucleotide sequence and prevalence of size variants of iceA1, iceA2, and babA2 PCR products were introduced in this analysis.

RESULTS:

The frequency of vacA s1 was associated (p<0.01) with moderate/severe grades of atrophic gastritis. The cagA, iceA1, iceA2, and babA2 genotypes were found in 70.6%, 66.4%, 33.6%, and 92.3% of strains, respectively. The frequency of iceA2 and its subtype iceA2_D were higher (p<0.015) in cases with moderate/severe granulocytic inflammation. The most prevalent combined genotypes were vacA s1m1/cagA/iceA1/babA2 (26.3%), vacA s2m2/iceA1/babA2 (19.5%), and vacA s1m1/cagA/iceA2/babA2 (18.8%). Sequence analysis of iceA1, iceA2, and babA2 PCR-amplified fragments allowed us to define allelic variants and to increase the number of genotypes detected (from 19 to 62). A phylogenetic tree made with iceA1 sequences showed that the H. pylori strains analyzed here were grouped with those of Western origin.

CONCLUSIONS:

Our results show that patients from the western region of Venezuela have an elevated prevalence of infection with H. pylori strains carrying known virulence genotypes with high genetic diversity. This highlights the importance of identifying gene variants for an early detection of virulent genotypes.

Atrophy of the gastric mucosa is a precursor of intestinal-type gastric cancer, and Helicobacter pylori infection causes atrophic gastritis. The aim of this study was to determine whether the genetic diversity of H. pylori virulence genes is associated with the development and progression of gastric atrophy in humans. We isolated and cultured H. pylori strains from patients with gastric ulcer and duodenal ulcer accompanied by atrophic gastritis in background mucosa. H. pylori strains were stored at －80℃ prior to the experiments being carried out. We analyzed iceA, babA, vacA, cagA, and cagE genes by PCR. The cagA gene was analyzed through sequencing of the C-terminal region containing the EPIYA motif, which is related to tyrosine phosphorylation. Severe atrophy was observed in patients with gastric ulcer. The major phenotype of the vacA gene was s1c/m1 (93%). The cagA gene was detected in all strains. The cagE gene was not detected in 2 and 5 strains from the mild cases and severe cases, respectively. The major cagA EPIYA motif, which is amino acids repeat in the C terminus, was the A-B-D type (44 of 58 strains). The virulence genes were not statistically associated with the severity of atrophy in the background gastric mucosa in humans. Not only identification of bacterial virulence factors but also studies of the host response will be necessary to investigate the progression of gastric atrophy and subsequent cancer development in humans.

To assess the diagnostic value of a combination of intragastric bile acids and hepatobiliary scintigraphy in the detection of duodenogastric reflux (DGR).The study contained 99 patients with DGR and 70 healthy volunteers who made up the control group. The diagnosis was based on the combination of several objective arguments: a long history of gastric symptoms (i.e., nausea, epigastric pain, and/or bilious vomiting) poorly responsive to medical treatment, gastroesophageal reflux symptoms unresponsive to proton-pump inhibitors, gastritis on upper gastrointestinal (GI) endoscopy and/or at histology, presence of a bilious gastric lake at > 1 upper GI endoscopy, pathologic 24-h intragastric bile monitoring with the Bilitec device. Gastric juice was aspirated in the GI endoscopy and total bile acid (TBA), total bilirubin (TBIL) and direct bilirubin (DBIL) were tested in the clinical laboratory. Continuous data of gastric juice were compared between each group using the independent-samples Mann-Whitney U-test and their relationship was analysed by Spearman's rank correlation test and Fisher's linear discriminant analysis. Histopathology of DGR patients and 23 patients with chronic atrophic gastritis was compared by clinical pathologists. Using the Independent-samples Mann-Whitney U-test, DGR index (DGRi) was calculated in 28 patients of DGR group and 19 persons of control group who were subjected to hepatobiliary scintigraphy. Receiver operating characteristic curve was made to determine the sensitivity and specificity of these two methods in the diagnosis of DGR.The group of patients with DGR showed a statistically higher prevalence of epigastric pain in comparison with control group. There was no significant difference between the histology of gastric mucosa with atrophic gastritis and duodenogastric reflux. The bile acid levels of DGR patients were significantly higher than the control values (Z: TBA: -8.916, DBIL: -3.914, TBIL: -6.197, all P < 0.001). Two of three in the DGR group have a significantly associated with each other (r: TBA/DBIL: 0.362, TBA/TBIL: 0.470, DBIL/TBIL: 0.737, all P < 0.001). The Fisher's discriminant function is followed: Con: Y = 0.002TBA + 0.048DBIL + 0.032TBIL - 0.986; Reflux: Y = 0.012TBA + 0.076DBIL + 0.089TBIL - 2.614. Eighty-four point zero five percent of original grouped cases were correctly classified by this method. With respect to the DGR group, DGRi were higher than those in the control group with statistically significant differences (Z = -5.224, P < 0.001). Twenty eight patients (59.6%) were deemed to be duodenogastric reflux positive by endoscopy, as compared to 37 patients (78.7%) by hepatobiliary scintigraphy.The integrated use of intragastric bile acid examination and scintigraphy can greatly improve the sensitivity and specificity of the diagnosis of DGR.