Non-invasive tests in gastric diseases

Identification of a high risk gastric cancer group using serum pepsinogen after successful eradication of Helicobacter pylori

BACKGROUND AND AIM

Pepsinogen (PG) method is widely used to identify high risk groups of gastric cancer. It is very useful before Helicobacter pylori eradication, but after eradication the method becomes useless because the PGI, PGII, PGI/II ratios change. Therefore, we aimed to identify a high risk group for gastric cancer using serum pepsinogen after successful eradication of H. pylori.

METHODS

A total of 261 participants were enrolled after successful eradication of H. pylori in Hokkaido University Hospital from 1995 to 2010. Participants with renal failure, taking proton pump inhibitors, and those with advanced gastric cancer were excluded. Serum levels of PGI and II were measured using chemiluminescent immunoassay method.

RESULTS

Receiver operating characteristic curves using cancerous and non-cancerous data in post-eradication determined the optimal cut-off value of PGI/II as 4.5. The sensitivity and the specificity were 65.9% and 79.3%, respectively. The usual PG method includes 48.9% of cancer cases, and the PGI/II ≤ 4.5 in post-eradication includes 65.9% of them, and it includes approximately half of the high risk group of diffuse type cancer. PGI/II ≤ 4.5 in post-eradication included many gastric cancer cases detected after eradication (12/16 = 75%).

CONCLUSION

In the identification of a high risk group for gastric cancer, we suggest that the optimal cut-off value of PGI/II after successful eradication of H. pylori is 4.5. PGI/II ≤ 4.5 in post-eradication includes more gastric cancer cases compared with the traditional PG method, and 75% of gastric cancer cases detected after eradication.

Serum pepsinogen-A, canine pancreatic lipase immunoreactivity, and C-reactive protein as prognostic markers in dogs with gastric dilatation-volvulus

BACKGROUND

Pepsinogens are proenzymes secreted by gastric chief cells. In humans, their serum concentrations reflect gastric mucosal morphological and functional status.

OBJECTIVES

To evaluate serum canine pepsinogen-A (cPG-A), C-reactive protein (CRP), and canine pancreatic lipase immunoreactivity (cPLI) concentrations in dogs with gastric dilatation-volvulus (GDV).

ANIMALS

Sixty-six dogs presented with GDV and 79 healthy controls.

METHODS

Blood was collected prospectively, and records retrospectively reviewed.

RESULTS

Median cPG-A concentration was higher in GDV dogs (median, 397 μg/L; range, 37-5,410) compared to controls (median, cPG-A 304 μg/L; range, 18-848; P = .07). Mortality rate in GDV dogs was 22.7%. In nonsurvivors of GDV, median cPG-A was higher compared to survivors (median, 746 μg/L; range, 128-5,409 versus median, 346; range, 36-1,575, respectively; P = .003). The proportion of dogs with increased cPG-A increased with gastric wall damage score (P = .007). An ROC analysis of cPG-A as a predictor of death showed an area under the curve (AUC) of 0.75, higher than lactate (AUC 0.66), and corresponded to a sensitivity and specificity of 53% and 88%, respectively. CRP was increased in 48 dogs (75%), cPLI was >200 μg/L in 26 dogs (39.4%) and >400 μg/L in 12 dogs (18.2%) but both analytes had no association with outcome.

CONCLUSIONS

Presurgical cPG-A concentration was positively and significantly associated with gastric wall lesion severity, but, based on ROC analysis, it was only a moderate outcome predictor. CRP and cPLI were commonly increased in dogs with GDV.

MiR-421 is a functional marker of circulating tumor cells in gastric cancer patients

The detection of circulating tumor cells (CTCs) has recently received great attention. To evaluate if miR-421 could be used as a specific marker for CTCs, the level of miR-421 in mononuclear cells (MNCs) from peripheral blood were determined by reverse transcription-polymerase chain reaction. Transfection of miR-421 inhibitor significantly suppressed tumor growth in vivo. The level of miR-421 in MNCs from gastric cancer was significantly higher than in those from healthy controls. The area under the receiver operating characteristic curve was 0.773 ± 0.0736. In conclusion, miR-421 may be used as a biomarker for monitoring CTCs in patients with gastric cancer.

Plasma soluble HLA-G is a potential biomarker for diagnosis of colorectal, gastric, esophageal and lung cancer

Human leukocyte antigen-G (HLA-G) is a novel tumor marker and its soluble isoforms produce secretory proteins. Increased soluble HLA-G (sHLA-G) levels have been reported in patients with melanoma, neuroblastoma, lymphoproliferative disorders, breast, ovarian and colorectal carcinoma when compared to healthy controls or subjects with benign neoplasms. The aim of this study is to investigate whether or not plasma sHLA-G can be used as a potential biomarker for cancer diagnosis. We measured plasma sHLA-G levels in 166 patients with early stages of colorectal cancer (CRC, n = 37), gastric cancer (GC, n = 28), esophageal squamous cell carcinoma (ESCC, n = 58) and non-small cell lung cancer (NSCLC, n = 43), and compared them to healthy controls (n = 260) by using a specific HLA-G enzyme-linked immunosorbent assay (ELISA). We found that plasma sHLA-G levels were significantly higher in cancer patients than in healthy controls (all P < 0.0001). The areas under the receiver-operating characteristic (ROC) curves for sHLA-G were 0.97, 0.91, 0.98 and 0.80 for healthy controls vs CRC, GC, ESCC and NSCLC, respectively. At 100% specificity, the highest sensitivity achieved to detect CRC, GC, ESCC and NSCLC was 94% [95% confidence interval (CI), 89-99], 85% (95% CI, 76-94), 91% (95% CI, 88-94) and 51% (95% CI, 43-59) at a cutoff value of 49 U/ml, respectively. These findings suggest that plasma sHLA-G may be a useful molecule in the differential diagnosis of these malignancies against healthy controls.

Value of gastrin-17 in detecting antral atrophy

PURPOSE

Decreased plasma gastrin-17 (G-17), particularly after protein stimulation, is indicative of atrophy in the antral stomach mucosa. Available data on the value of this biomarker is inconclusive. Our study was aimed to evaluate the performance of the G-17 test in Caucasian and Asian patients for antral atrophy evaluation either in fasting state or after protein stimulation.

MATERIAL/METHODS

241 dyspeptic patients aged 55 and above from Latvia (125), Lithuania (76) and Taiwan (40) were enrolled. G-17 levels were detected in plasma samples obtained either during fasting or after a protein-rich test meal. Levels <1 pmol/L at fast and <5 pmol/L after stimulation were considered indicative of atrophy.

RESULTS

The sensitivity of the test was 15.8%, its specificity 88.7%, and the overall accuracy 83% in the fasting state, and 36.8, 86.5, and 82.6%, respectively, after stimulation. In the Caucasian subgroup, the corresponding figures were 15.4, 91.5, and 86.6% in the fasting state and 30.8, 92.6, 88.6% after stimulation; but for the Asian subgroup the corresponding figures were 16.7, 73.5, and 65% (fasting) and 50, 52.9, and 52.5% (stimulated).

CONCLUSIONS

The performance of G-17 was better after protein stimulation. G-17 was highly specific in the Caucasian, but not in the Asian subgroups. Still the low test sensitivity either at fast or following protein stimulation does not allow us to recommend it for wide screening purpose to diagnose antral atrophy.

Genome-wide microRNA profiles identify miR-378 as a serum biomarker for early detection of gastric cancer

Recent studies demonstrated that in several human malignancies aberrant expression profiles of circulating microRNAs (miRNAs) anticipate great cancer diagnostic potential. Here we showed that serum miR-378 could serve as a novel noninvasive biomarker in gastric cancer (GC) detection. Genome-wide miRNA expression profiles followed with Real-Time quantitative RT-PCR (qRT-PCR) assays revealed that miR-187(*), miR-371-5p and miR-378 were significantly elevated in GC patients. Further validation indicated that miR-378 alone could yields a ROC curve area of 0.861 with 87.5% sensitivity and 70.73% specificity in discriminating GC patients from healthy controls. Collectively, these data support our contention that serum miR-378 has strong potential as a novel noninvasive biomarker in gastric cancer detection.

Production of ectopic gastric intrinsic factor in gastric mucosa of humans with chronic gastritis

BACKGROUND

Ectopic expression of gastric intrinsic factor (IF) has been described in rodent models of chronic gastritis.

AIMS

The current study undertook to determine if ectopic IF was also present in chronic gastritis in humans and might identify the process of ectopic protein expression as part of the response to chronic injury.

METHODS

Archived biopsies from mid-body, angularis and prepylorus of 9 patients with and without chronic gastritis and food-cobalamin malabsorption were examined in a blinded fashion by immunocytochemistry as were biopsies from 5 normal subjects. Cells with ectopic IF were further examined with antibodies against pepsin or with Griffonia simplicifolia II (GSII) to identity cells in the mucous neck cell compartment.

RESULTS

Ectopic IF production in non-parietal cells was identified in cells that were H(+),K(+)-ATPase-negative but IF-positive in 7 of the 9 patients (6/9 in the angularis and/or prepylorus biopsies and 1/9 only in the mid-body). These included 5 of the 6 H. pylori-infected patients and all 5 patients with severe food-cobalamin malabsorption. No normal control subjects demonstrated ectopic IF. The cells with ectopic IF were pepsinogen-positive peptic cells and were not GSII-positive. Expression was most extensive in patients and gastric regions with inflammation. In all but one sample, ectopic IF was observed near anatomical mucosal junctions, such as antral/body and prepylorus/duodenum junctions.

CONCLUSIONS

These data in humans with and without gastritis are consistent with the hypothesis that local factors influence ectopic gastric IF expression, arising from either the anatomical location, the focal inflammation, or both.

Ghrelin in gastrointestinal disease

Enteroendocrine cells of the gastric fundus are the predominant source of ghrelin production, although ghrelin gene transcripts and ghrelin-producing cells have been identified throughout the gastrointestinal tract. Various infectious, inflammatory and malignant disorders of the gastrointestinal system have been shown to alter ghrelin production and secretion and consequently to affect endocrine ghrelin levels and activity. Animal studies have demonstrated that ghrelin and synthetic ghrelin mimetics can reduce the severity of gastric and colonic inflammation and human clinical trials are underway to determine the efficacy of ghrelin in improving motility disorders. This review summarises the impact of gastrointestinal disease on ghrelin synthesis and secretion and the potential use of ghrelin and its mimetics for the treatment of these diseases.

Low serum levels of pepsinogen and gastrin 17 are predictive of extensive gastric atrophy with high-risk of early gastric cancer

Atrophic gastritis (AG) is a well-recognized high-risk condition for developing gastric cancer (GC). Gastrin 17 (G17), a hormone secreted from antral G cells, regulates gastric acid secretion, and its serum level is a possible indicator of antral atrophy. Serum pepsinogen is well established as the indicator of AG involving the corpus. Here we investigated whether serum PG and G17 levels would be useful for determining the topographic pattern of AG and estimating the risk of GC. Enrolled were 122 Japanese patients with early GC (114 well- to moderate-differentiated cancers and 8 poorly-differentiated cancers). In addition, 178 subjects without GC were recruited as control from those undergoing endoscopic examination (non-GC group). All subjects were histologically assigned to the following four groups: non-AG, antrum-predominant AG, corpus-predominant AG, and multifocal AG, affecting the antrum and corpus. Serum concentrations of pepsinogen and G17 were determined using ELISA. Multifocal AG was more frequent in the GC group than in the adjusted non-GC group, and had the highest risk of GC (OR 25.1). Serum G17 was significantly decreased with the exacerbation of antral atrophy in the coexistence of corpus atrophy. Serum biomarker profiles showed that the low levels of pepsinogen and G17 could discriminate between multifocal AG and other types of AG, but not with pepsinogen level alone. Serologically defined multifocal AG had the highest cancer risk among other serologically defined AG groups (OR 26.9). In conclusion, the low serum levels of pepsinogen and G17 are predictive of extensive gastric atrophy with high-risk of early GC.

Helicobacter pylori infection and current clinical areas of contention

PURPOSE OF REVIEW

The indication for Helicobacter pylori (H. pylori) eradication has been extended to few extragastroduodenal diseases. Scientific rigor needs to be applied as the list of clinical manifestations potentially related to H. pylori has disproportionally grown to its scientific evidence. Some potential beneficial aspects of H. pylori in allergic diseases and in the context of obesity are critically addressed in this review. The main challenge, however, continues to be the prevention of gastric cancer by H. pylori eradication. Strategies for identification of individuals and populations at risk are reported as well. A final aspect is dedicated to novel treatment regimens for overcoming the increasing treatment failures with proton pump inhibitor-based triple standards.

RECENT FINDINGS

H. pylori infection is associated with some extragastric diseases such as idiopathic thrombocytic purpura and iron deficiency anemia that benefit from eradication therapy. The inverse relation of H. pylori prevalence and the increase in allergies and obesity, as reported from epidemiological studies, has prompted research for elucidating potential underlying pathophysiological mechanisms. Strategies for gastric cancer prevention include serological screening, which allow adopting eradication therapy in individuals at high risk. New treatments for H. pylori include sequential, bismuth-based quadruple and nonbismuth-based quadruple therapies.

SUMMARY

The main clinical challenge remains prevention of H. pylori-related diseases by effective treatment and screening procedures.

MicroRNA dysregulation in gastric cancer: a new player enters the game

Gastric carcinogenesis is a multistep process involving genetic and epigenetic alteration of protein-coding proto-oncogenes and tumor-suppressor genes. Recent discoveries have shed new light on the involvement of a class of noncoding RNA known as microRNA (miRNA) in gastric cancer. A substantial number of miRNAs show differential expression in gastric cancer tissues. Genes coding for these miRNAs have been characterized as novel proto-oncogenes and tumor-suppressor genes based on findings that these miRNAs control malignant phenotypes of gastric cancer cells. In this connection, miRNA dysregulation promotes cell-cycle progression, confers resistance to apoptosis, and enhances invasiveness and metastasis. Moreover, certain polymorphisms in miRNA genes are associated with increased risks for atrophic gastritis and gastric cancer, whereas circulating levels of miRNAs may serve as biomarkers for early diagnosis. Several miRNAs have also been shown to correlate with gastric cancer progression, and thus may be used as prognostic markers. Elucidating the biological aspects of miRNA dysregulation may help us better understand the pathogenesis of gastric cancer and promote the development of miRNA-directed therapeutics against this deadly disease.

Clinical relevance of cagPAI intactness in Helicobacter pylori isolates from Vietnam

The purpose of this paper is to investigate the relationship between clinical outcome and the intactness of cagPAI in Helicobacter pylori strains from Vietnam. The presence or absence of 30 cagPAI genes was investigated by polymerase chain reaction (PCR) and dot-blotting. H. pylori-induced interleukin-8 secretion and hummingbird phenotype, and H. pylori adhesion to gastric epithelial cells were examined. The serum concentration of pepsinogen 1, pepsinogen 2, and gastrin was also measured in all patients. cagPAI was present in all 103 Vietnamese H. pylori isolates, of which 91 had intact cagPAI and 12 contained only a part of cagPAI. Infection with the partial cagPAI strains was less likely to be associated with peptic ulcer and chronic gastric mucosal inflammation than infection with strains possessing intact cagPAI. The partial cagPAI strains lacked almost all ability to induce interleukin-8 secretion and the hummingbird phenotype in gastric cells. Their adhesion to epithelial cells was significantly decreased in comparison with intact cagPAI strains. Moreover, for the first time, we found an association between cagPAI status and the serum concentration of pepsinogens 1 and 2 in infected patients. H. pylori strains with internal deletion within cagPAI are less virulent and, thus, less likely to be associated with severe clinical outcomes.

Five serum proteins identified using SELDI-TOF-MS as potential biomarkers of gastric cancer

OBJECTIVE

The aims of this study were to detect serum proteomic patterns in gastric cancer serum samples using Surface-enhanced Laser Desorption/ionization-Time-of-flight-Mass Spectrometry ProteinChip array technology, to screen biomarker candidates, to build diagnostic models and to evaluate their clinical significance.

METHODS

Serum samples from patients with gastric cancer and normal healthy control subjects (n = 125) were analysed using surface-enhanced laser desorption/ionization technology. The spectra were generated on weak cation exchange (WCX2) chips, and protein peak clustering and classification analyses were established using Ciphergen Biomarker Wizard and Biomarker Pattern software, respectively. The diagnostic models were developed and validated by discriminant analysis. In addition, the results of the surface-enhanced laser desorption/ionization model were compared with the biomarkers carcinoembryonic antigen and carbohydrate antigen 199 in a subset of samples using a microparticle enzyme immunoassay.

RESULTS

Five protein peaks at 2046, 3179, 1817, 1725 and 1929 m/z were automatically chosen as components of the best biomarker pattern for diagnosis of gastric cancer. In addition, we identified a single protein peak at 4665 m/z, which could distinguish between stage I/II and stage III/IV gastric cancer with a specificity and sensitivity of 91.6% (11/12) and 95.4% (21/22), respectively. When this biomarker was validated in the second set of samples, the specificity and sensitivity were 91.7% (11/12) and 86.3% (19/22), respectively.

CONCLUSIONS

The present results suggest that serum surface-enhanced laser desorption/ionization protein profiling can distinguish patients with gastric cancer, and in particular stage I/II patients, from normal subjects with a relatively high sensitivity and specificity. Surface-enhanced Laser Desorption/ionization-Time-of-flight-Mass Spectrometry is a potential new diagnostic tool for the screening of gastric cancer.

Gastric ghrelin in relation to gender, stomach topography and Helicobacter pylori in dyspeptic patients

AIM: To investigate the level of gastric ghrelin in stomach mucosa of dyspeptic patients in relation to Helicobacter pylori (H pylori) infection, bacterial cytotoxicity, topography and gender.

METHODS: The study comprised 40 premenopausal women (19 H pylori positive) and 48 men (17 H pylori positive) with functional dyspepsia. All gastric biopsy specimens revealed normal mucosa or non-atrophic gastritis. Gastric ghrelin concentration was determined by Enzyme linked immunosorbent assay. The cagA and vacA strains of bacterial DNA were identified by multiplex polymerase chain reaction.

RESULTS: In general, infection with H pylori caused an increase in gastric ghrelin level regardless of gender and stomach topography. Significantly more hormone was present in both, non-infected and H pylori positive female samples, as compared to males. The distribution of bacterial strains showed cagA(+) vacA s1m1 and cagA(-) vacA s2m2 genotypes as the most common infections in the studied population. A tendency to higher ghrelin levels was observed in less cytotoxic (cagA negative) strain-containing specimens from the antrum and corpus of both gender groups (without statistical significance).

CONCLUSION: An increase in gastric ghrelin levels at the stage of non-atrophic gastritis in H pylori positive patients, especially in those infected with cagA(-) strains, can exert a gastroprotective effect.

The validity of a biomarker method for indirect detection of gastric mucosal atrophy versus standard histopathology

BACKGROUND

Atrophy of the stomach mucosa is considered to be premalignant lesion for gastric cancer development; easy identification of this condition from a blood-sample would allow identifying the group of individuals at increased risk for cancer development.

AIMS

The objective of the current study was to validate a biomarker method (pepsinogen I/II ratio and gastrin-17) for indirect detection of atrophy of the stomach mucosa versus standard histopathology in Caucasian and Asian populations.

METHODS

Altogether, 241 patients aged 55 and above referred for upper endoscopy due to dyspeptic symptoms (125 from Latvia, 76 from Lithuania, and 40 from Taiwan) were enrolled. Pepsinogen I, pepsinogen II, gastrin-17 (the latter after stimulation with protein-rich meal) and IgG/IgA antibodies to Helicobacter pylori infection were determined by ELISA method; standard histopathology according to the updated Sydney classification read by two independent expert pathologists was used for the comparison.

RESULTS

Pepsinogen I/II ratio below 3 was well related to atrophy (moderate to severe) in the corpus part of the stomach (P < 0.0001) with 83.3% sensitivity and 87.1% specificity. Gastrin-17 below 5 pmol/L was related to atrophy in the antral part (P = 0.007) with 36.8% sensitivity and 86.5% specificity.

CONCLUSIONS

Decreased pepsinogen I/II ratio is a reliable marker for atrophy in the corpus, and may be recommended for identification of individuals with this type of atrophy. The utility of gastrin-17 for the detection of atrophy in the antral part of the stomach still requires further evaluation due to the low sensitivity.