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

Assessing the utility of pepsinogens and gastrin-17 in gastric cancer detection

OBJECTIVES

The aim of the study was to determine the proportion of gastric cancer patients with decreased levels of pepsinogen and gastrin-17 in plasma, with the goal of providing indirect evidence of the sensitivity of these biomarkers when applied in a cancer screening setting.

METHODS

The levels of pepsinogens I and II, gastrin-17, and Helicobacter pylori immunoglobulin antibodies in plasma samples of gastric cancer patients were evaluated using the GastroPanel test system (Biohit Oyj, Helsinki, Finland). A decreased level of the pepsinogen I/II ratio was defined as less than three, while a decrease in gastrin-17 was defined as less than 1 pmol/L. Univariate analysis using non-parametric tests was used to investigate differences between normal and low concentrations of biomarkers.

RESULTS

In total, 481 plasma samples from patients (59.9% male) with a median age of 64 years (ranging from 27 to 88 years) were analyzed. Out of the 400 cases of gastric cancer (83.2% of the total), 182 were categorized as the intestinal type, 141 as the diffuse type, 60 as the mixed type, and 17 as indeterminate according to the Lauren classification system. The H. pylori immunoglobulin test was positive in 74.0% of the patients. Pepsinogen I/II ratio was decreased in 32.4% (36.8% of the intestinal type); gastrin-17 in 12.3% (10.1% of the antral region) of all cases.

CONCLUSION

The majority of gastric cancer patients had normal levels of pepsinogen and gastrin-17, suggesting that these biomarkers have limited application as screening tools in the Caucasian population.

Development of amplified luminescent proximity homogeneous assay for quantitation of gastrin-17

A highly sensitive and convenient amplified luminescent proximity homogeneous assay (AlphaLISA) method with high throughput and automation potential was developed for quantitation of serum Gastrin-17 (G-17) levels, which can facilitate the early diagnosis of atrophic gastritis in people at high risk of gastric cancer using a non-invasive approach. In this study, donor and acceptor beads with modified carboxyl groups on the surface were directly coupled to anti-G-17 antibodies through activation was proposed for application in the development of the new AlphaLISA, which can effectively simplify the steps and shorten the reaction time to achieve faster detection. Therefore, the G-17-AlphaLISA only needs to react for 15 min to obtain good analysis results. The proposed method has a wider detection range than commercial enzyme-linked immunosorbent assay (ELISA) kits (0.12-112.8 pmol/L > 0.5-40 pmol/L). In addition, results of G-17-AlphaLISA and ELISA had good correlation and agreement (ρ = 0.936). Importantly, the developed method may be more suitable for the large-scale screening of people at high risk for gastric cancer than traditional ELISA and provides a novel solution for other biomarkers that require accurate, highly sensitive, and high throughput detection.

The Diagnostic Value of Anti-Parietal Cell and Intrinsic Factor Antibodies, Pepsinogens, and Gastrin-17 in Corpus-Restricted Atrophic Gastritis

We aimed to determine the diagnostic value of anti-parietal cell antibodies (anti-PCA), anti-intrinsic factor antibodies (anti-IFA), pepsinogen ratio (PGI/II), and gastrin-17 (G-17) in corpus-restricted atrophic gastritis (CRAG) detected by ELISA (Inova, Biohit). Our study compared 29 CRAG cases against 58 age- and sex-matched controls with mild or no atrophy. Anti-PCA and anti-IFA positive cutoff values were ≥25 units for both. PGI/II value <3 was considered characteristic for atrophy; positive cutoff values for G-17 and anti-H. pylori IgG were >5 pg/L and >30 EIU. Anti-PCA was positive in 65.5% For CRAG cases and 13.8% of the controls (p < 0.0001), anti-IFA was positive in 13.8% and 0% (p = 0.01), respectively. Decreased pepsinogen levels were present in 79.3% of CRAG cases and 10.3% of the controls (p < 0.0001). PGI/II ratio was the best single biomarker, with sensitivity = 79%, specificity = 90%, and AUC 0.90. The combined use of PGI/II and anti-PCA resulted in AUC 0.93 for detecting CRAG. Our study suggests that the best combination of non-invasive biomarkers for detecting CRAG is PGI/II with anti-PCA. The addition of G-17 and anti-IFA is of little utility in clinical application.

Advancements in Gastrointestinal System Biomarkers

The requirement for diagnostic surgical operations of gastrointestinal system diseases significantly decreases with the help of proper diagnostic tools. These modalities are also beneficial for identifying postoperative complications, allowing us to diagnose them in earlier stages, and increasing the postoperative survival rates. Biomarkers are considered an integral part of diagnostic examinations. Developments of biomarkers used for diagnosing and treating abdominal diseases are essential for improving our capabilities in non-invasive monitoring. In this chapter, we review both the novel and the routine biomarkers in the diagnosis and follow-up of gastrointestinal system diseases.

Serum Pepsinogen as a Biomarker for Gastric Cancer in the United States: A Nested Case-Control Study Using the PLCO Cancer Screening Trial Data

BACKGROUND

Gastric cancer lacks specific symptoms, resulting in diagnosis at later stages and high mortality. Serum pepsinogen is a biomarker for atrophic gastritis, a gastric cancer precursor, and may be useful to detect persons at increased risk of gastric cancer.

METHODS

The Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial was conducted in the United States between 1993 and 2001. ELISA-based pepsinogen tests were conducted on prediagnostic serum samples of 105 PLCO participants who developed gastric cancer and 209 age, sex, and race-matched controls. Pepsinogen positive (PG+) was defined as pepsinogen I ≤ 70 μg/L and pepsinogen I/II ratio ≤3.0. Results of conditional logistic regression models, and sensitivity and specificity, of PG+ for gastric cancer are reported.

RESULTS

Gastric cancer cases were more likely to be PG+ (31.4% vs. 5.5%, P < 0.001) at baseline than controls. Compared to PG-, PG+ was associated with an 8.5-fold increased risk for gastric cancer [95% confidence interval (CI) = 3.8-19.4]. This risk remained significant after adjusting for Helicobacter pylori, family history of gastric cancer, education, smoking, and BMI (aOR, 10.6; 95% CI, 4.3-26.2). In subgroup analysis, PG+ individuals were 11-fold more like to develop non-cardia gastric cancer (OR, 11.1; 95% CI, 4.3-28.8); conversely, they were not significantly more likely to develop cardia gastric cancer (OR, 2.0; 95% CI = 0.3-14.2). PG+ status yielded low sensitivity but high specificity for both noncardia (44.3%; 93.6%) and cardia gastric cancer (5.7%; 97.2%).

CONCLUSIONS

Prediagnostic serum pepsinogen levels from a large, prospective cohort study were associated with risk of gastric cancer, particularly noncardia gastric cancer.

IMPACT

PG status may identify individuals at higher risk of noncardia gastric cancer for targeted screening or interventions. See related commentary by Zhou and Huang, p. 1257.

Analysis of Gastric Diseases and Their Symptoms Based on Indexes of Pepsinogen I (PGI) and Pepsinogen II (PGII): Take 1106 Patients as Samples

In this study, preoperative analysis of 1106 gastropathy patients with abdominal pain, vomiting, dyspepsia, and other symptoms was conducted. Independent sample $t$ -test and correlation analysis and other ways were used for data cleansing and analysis. Findings were as follows: (1) Samples of different genders showed significance in PGI and PGII. The PGI and PGII values of women were significantly lower than those of men. (2) Age showed a significant positive correlation with PGI and PGII, which indicates that as the age increases, the PGI and PGII values become higher. (3) There was a significant negative correlation between age and abdominal pain. This signified that the younger the patient is, the more likely they will suffer abdominal pain. (4) PGI displayed a positive correlation with abdominal pain in the digestive tract (dyspepsia, gastrointestinal ulcers, gastrointestinal bleeding, etc.). It indicated that the higher the PGI value is, the more likely the patients will suffer abdominal pain and gastrointestinal diseases (dyspepsia, gastrointestinal ulcer, gastrointestinal hemorrhage, etc.). (5) PGII displayed a significant positive correlation with gastrointestinal diseases (dyspepsia, gastrointestinal ulcer, gastrointestinal hemorrhage, etc.) and a negative correlation with gastropathy (acute gastritis, chronic superficial gastritis, gastric ulcer, etc.). It indicated that the higher the value of PGII is, the more likely the patients will suffer symptoms of gastrointestinal diseases (dyspepsia, gastrointestinal ulcer, gastrointestinal hemorrhage, etc.), while less likely the patients will suffer gastropathy (acute gastritis, chronic superficial gastritis, gastric ulcer, etc.).

Nanozyme enhanced magnetic immunoassay for dual-mode detection of gastrin-17

A lateral flow detection was developed for dual-mode detection of gastrin-17, including nanozyme-enhanced chromatographic detection and magnetic quantification.

Acupuncture Regulates Serum Differentially Expressed Proteins in Patients with Chronic Atrophic Gastritis: A Quantitative iTRAQ Proteomics Study

Objective

To identify differentially expressed proteins (DEPs) in sera of patients with chronic atrophic gastritis (CAG) using isobaric tags for relative and absolute quantitation (iTRAQ) and to explore acupuncture's mechanism in CAG.

Methods

Peripheral sera from 8 healthy volunteers (HC), 8 chronic nonatrophic gastritis (NAG) patients, 8 CAG patients, and 8 CAG patients who underwent acupuncture treatment (CAG + ACU) were collected followed by labeling with iTRAQ reagent for protein identification and quantification using two-dimensional liquid chromatography-tandem mass spectrometry (2D-LC-MS/MS). Representative DEPs were selected through bioinformatics, and proteins were verified by enzyme-linked immunosorbent assay (ELISA).

Results

A total of 4,448 unique peptides were identified, corresponding to 816 nonredundant proteins. A 1.4-fold difference was used as the threshold. Compared with the HC group, 75 and 106 DEPs were identified from CAG and NAG groups, respectively. Compared with the CAG group, 110 and 66 DEPs were identified from the NAG and CAG + ACU groups, respectively. The DEPs were mainly involved in protein binding and the Notch signaling pathway-related proteins, and the upregulated proteins included actin-binding proteins (thymosin beta-4, tropomyosin-4, profilin-1, transgelin-2), while the downregulated proteins included Notch2 and Notch3. After acupuncture, the expression of these proteins in CAG patients was less differentiated from that in healthy people. The level of the above 6 proteins were verified by ELISA, and the results were similar to the results of iTRAQ analysis.

Conclusions

Actin-binding proteins and Notch signaling pathway-related proteins were correlated with the development and progression of CAG and thus are potential diagnostic markers for CAG. Acupuncture may play a role in regulating actin-binding proteins and Notch signaling pathway-related proteins to play a therapeutic role in CAG.

Identifying Novel Biomarkers Ready for Evaluation in Low-Prevalence Populations for the Early Detection of Upper Gastrointestinal Cancers: A Systematic Review

Introduction

Detecting upper gastrointestinal (GI) cancers in primary care is challenging, as cancer symptoms are common, often non-specific, and most patients presenting with these symptoms will not have cancer. Substantial investment has been made to develop biomarkers for cancer detection, but few have reached routine clinical practice. We aimed to identify novel biomarkers for upper GI cancers which have been sufficiently validated to be ready for evaluation in low-prevalence populations.

Methods

We systematically searched MEDLINE, Embase, Emcare, and Web of Science for studies published in English from January 2000 to October 2019 (PROSPERO registration CRD42020165005). Reference lists of included studies were assessed. Studies had to report on second measures of diagnostic performance (beyond discovery phase) for biomarkers (single or in panels) used to detect pancreatic, oesophageal, gastric, and biliary tract cancers. We included all designs and excluded studies with less than 50 cases/controls. Data were extracted on types of biomarkers, populations and outcomes. Heterogeneity prevented pooling of outcomes.

Results

We identified 149 eligible studies, involving 22,264 cancer cases and 49,474 controls. A total of 431 biomarkers were identified (183 microRNAs and other RNAs, 79 autoantibodies and other immunological markers, 119 other proteins, 36 metabolic markers, 6 circulating tumour DNA and 8 other). Over half (n = 231) were reported in pancreatic cancer studies. Only 35 biomarkers had been investigated in at least two studies, with reported outcomes for that individual marker for the same tumour type. Apolipoproteins (apoAII-AT and apoAII-ATQ), and pepsinogens (PGI and PGII) were the most promising biomarkers for pancreatic and gastric cancer, respectively.

Conclusion

Most novel biomarkers for the early detection of upper GI cancers are still at an early stage of matureness. Further evidence is needed on biomarker performance in low-prevalence populations, in addition to implementation and health economic studies, before extensive adoption into clinical practice can be recommended.

Electronic Supplementary Material

The online version of this article (10.1007/s12325-020-01571-z) contains supplementary material, which is available to authorized users.

Bio-assay of the non-amidated progastrin-derived peptide (G17-Gly) using the tailor-made recombinant antibody fragment and phage display method: a biomedical analysis

In this research, four novel and sensitive immunosensors for electrochemical determination of G17-Gly were designed based on signal amplification and tailor-made recombinant antibody technology. Anti-G17-Gly antibody fragments (i.e. scFv and VL specific to the N- and C-terminal of G17-Gly) were immobilized onto a polymeric nanocomposite comprising poly cetyl trimethyl ammonium bromide (P(CTAB)) as the conductive matrix, chitosan (CS) as a biocompatible agent and gold nanoparticles (AuNPs) as the signal amplification element. The high surface area provided by AuNPs and the small size of scFv/VL establish the basis for immobilizing a high amount of the anti-G17-Gly on the surface of the electrode for detecting G17-Gly in human plasma samples. Under optimal conditions, the designed immunosensors provide an excellent analytical capability for detecting and determining G17-Gly in human plasma samples with a linear range from 0.5 mM to 0.05 pM and a LLOQ of 0.05 pM. The sensitivity order of the immunosensors was Ag/2-mercaptoethanol/phage displaying scFv/P(CTAB-CS)-AuNP/GE, Ag/2-mercaptoethanol/phage displaying VL/P(CTAB-CS)-AuNP/GE, Ag/BSA/scFv/P(CTAB-CS)-AuNP/GE, and Ag/BSA/VL/P(CTAB-CS)-AuNP/GE. The aforementioned characteristics demonstrate that the proposed immune-devices can be used in biological and clinical diagnosis as reliable tools for identifying different oncobiomarkers.

Screening, Monitoring, and Treatment of Precancerous Atrophic Gastritis in the Prospective Study for Seven Years

AIM

Develop a program to identify, treat, and prevent severe atrophic gastritis to reduce gastric cancer incidence and mortality.

MATERIALS AND METHODS

In total, 2,847 people aged > 40 years old underwent serological noninvasive screening for atrophic gastritis by identifying postprandial gastrin-17 and pepsinogen-1 in the fasting state. Anti-H pylori IgG was found in 2,134 patients. Seven years later, 2,220 patientswho had undergone serological noninvasive screening were asked to fill out a questionnaire survey (were interviewed). We could not find any information on 627 of 2,847 patients. Next, 75 patients with multifocal atrophic gastritis who underwent gastroscopy and biopsies (the Updated Sydney System (USS)) were selected. To study gastrin-17 production, morpho-functional correlation was studies in 75 patients with multifocal atrophic gastritis.

RESULTS

During seven years, no reported case of gastric cancer was done among 2,220 persons who underwent serological screening and treatment. In the same population, 4.3 persons who did not receive screening during the same period, developed gastric cancer and died of it. In this study, we can say that 4.3 lives were saved out of 2,220 tested persons. The cost for screening this number of people amounted to €23,750. A comparison of the prevalence rate of the four stages of multifocal atrophic gastritis based on the data of the histopathology tests and noninvasive serologic screening in accordance with OLGA classification showed a strong correlation (the correlation coefficient is 0.812). This finding suggested that using this classification not only for histopathology tests for atrophic gastritis but also for serologic markers of antral mucosa and corpus ventriculi atrophy: gastrin-17 and pepsinogen-1.

CONCLUSION

Complex pathogenetic treatment of atrophic gastritis significantly reduced gastric cancer risk and incidence for such patients.
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Prediction of Chronic Atrophic Gastritis and Gastric Neoplasms by Serum Pepsinogen Assay: A Systematic Review and Meta-Analysis of Diagnostic Test Accuracy

Serum pepsinogen assay (sPGA), which reveals serum pepsinogen (PG) I concentration and the PG I/PG II ratio, is a non-invasive test for predicting chronic atrophic gastritis (CAG) and gastric neoplasms. Although various cut-off values have been suggested, PG I ≤70 ng/mL and a PG I/PG II ratio of ≤3 have been proposed. However, previous meta-analyses reported insufficient systematic reviews and only pooled outcomes, which cannot determine the diagnostic validity of sPGA with a cut-off value of PG I ≤70 ng/mL and/or PG I/PG II ratio ≤3. We searched the core databases (MEDLINE, Cochrane Library, and Embase) from their inception to April 2018. Fourteen and 43 studies were identified and analyzed for the diagnostic performance in CAG and gastric neoplasms, respectively. Values for sensitivity, specificity, diagnostic odds ratio, and area under the curve with a cut-off value of PG I ≤70 ng/mL and PG I/PG II ratio ≤3 to diagnose CAG were 0.59, 0.89, 12, and 0.81, respectively and for diagnosis of gastric cancer (GC) these values were 0.59, 0.73, 4, and 0.7, respectively. Methodological quality and ethnicity of enrolled studies were found to be the reason for the heterogeneity in CAG diagnosis. Considering the high specificity, non-invasiveness, and easily interpretable characteristics, sPGA has potential for screening of CAG or GC.

The Difference of Serum Gastrin-17 Level Based on Gastritis Severity and Helicobacter Pylori Infection

BACKGROUND

Gastritis was defined as the histological presence of gastric mucosal inflammation. One of the most common aetiology was H. pylori. Gastrin-17 was a hormone that was secreted by G cells. H. pylori infection induced increased in gastrin-17 in gastritis. Therefore, this study was to investigate the relationship of gastrin-17 with gastritis severity and H. pylori infection.

AIM

To determine the difference in serum Gastrin-17 level based on gastritis severity and H. pylori infection.

METHODS

A cross-sectional study enrolling 45 patients with gastritis was conducted in Haji Adam Malik General Hospital between April and July 2018. Endoscopy and biopsy examinations were performed to confirm the diagnosis of gastritis. Gastritis severity was assessed using the Updated Sydney System. The presence of H. pylori infection was detected by a Campylobacter-like organism (CLO) examination. Gastrin-17 level and demographic data were also gathered. The analysis was done using Mann Whitney and Kruskal-Wallis test. P-value of < 0.05 was considered statistically significant.

RESULTS

Serum Gastrin-17 level was significantly different based on gastritis severity (P = 0.001 according to neutrophils infiltration and P = 0.023 according to degree of atrophy), H. pylori infection (P = 0.038), and combined gastritis severity and H. pylori infection (P < 0.001). Serum Gastrin-17 level was higher in subjects with severe neutrophils infiltration, without atrophy, and with H. pylori infection.

CONCLUSION

There was a significant difference in serum Gastrin-17 level based on gastritis severity and H. pylori infection.

Association between atherosclerosis and gastric biomarkers concerning Helicobacter pylori infection in a Chinese healthy population

BACKGROUND

Studies have suggested that Helicobacter pylori (Hp) infection is associated with atherosclerotic process, while the relationship between pepsinogens, gastrin and atherosclerosis is unknown.

AIM

The aim of the study was to observe association of Hp infection on atherosclerotic parameters and blood pressure, and explore the relationship between atherosclerotic parameters, blood pressure and gastric biomarkers in a healthy population.

METHODS

395 subjects were chosen and received physical examinations, carotid artery ultrasound, peripheral atherosclerosis measurement, and testing of serum pepsinogen (PG) I and II, Hp antibody, and gastrin-17 (G-17) levels. Analyses were conducted by Student's t-test, ANOVA, Pearson correlation, multiple linear regression and binary logistic regression.

RESULTS

In Hp-infected subjects, right carotid intima media thickness (R-CIMT) were higher (P = 0.027) and left ankle brachial index were higher in 45-64 years compared to 35-44 years group (P = 0.039, P = 0.016). Hp-IgG, PGI and G-17 respectively positively correlated with CIMT, pulse wave velocity and systolic blood pressure (P = 0.044, P = 0.013, P = 0.021). The unadjusted OR in subjects with elevated CIMT for quartile IV of PGI was 3.542 (95% CI, 1.491-8.411), the adjusted OR was 2.916 (95% CI, 1.035-8.216). The unadjusted OR in subjects with elevated CIMT for quartile III of G-17 was 4.351 (95% CI, 1.670-11.336) and for quartile IV was 3.108 (95% CI, 1.149-8.406), the adjusted OR for quartile III was 4.962 (95% CI, 1.515-16.258).

CONCLUSIONS

Hp infection, higher levels of PGI and G-17 may contribute to atherosclerotic process by influencing atherosclerotic parameters and blood pressure in a healthy population, the influence on CIMT was most significant.

Systematic review with meta-analysis: diagnostic performance of the combination of pepsinogen, gastrin-17 and anti-Helicobacter pylori antibodies serum assays for the diagnosis of atrophic gastritis

BACKGROUND

The combination of pepsinogen, gastrin-17 and anti-H. pylori antibodies serological assays (panel test) is a non-invasive tool for the diagnosis of atrophic gastritis. However, the diagnostic reliability of this test is still uncertain.

AIM

To assess the diagnostic performance of the serum panel test for the diagnosis of atrophic gastritis.

METHODS

Medline via PubMed, Embase, Scopus, Cochrane Library databases and abstracts of international conferences proceedings were searched from January 1995 to December 2016 using the primary keywords "pepsinogens," "gastrin," "atrophic gastritis," "gastric precancerous lesions." Studies were included if they assessed the accuracy of the serum panel test for the diagnosis of atrophic gastritis using histology according to the updated Sydney System as reference standard.

RESULTS

Twenty studies with a total of 4241 subjects assessed the performance of serum panel test for the diagnosis of atrophic gastritis regardless of the site in the stomach. The summary sensitivity was 74.7% (95% confidence interval (CI), 62.0-84.3) and the specificity was 95.6% (95%CI, 92.6-97.4). With a prevalence of atrophic gastritis of 27% (median prevalence across the studies), the negative predictive value was 91%. Few studies with small sample size assessed the performance of the test in detecting the site of atrophic gastritis.

CONCLUSIONS

The combination of pepsinogen, gastrin-17 and anti-H. pylori antibodies serological assays appears to be a reliable tool for the diagnosis of atrophic gastritis. This test may be used for screening subjects or populations at high risk of gastric cancer for atrophic gastritis; however, a cost-effectiveness analysis is needed.

A Chronological Increase in Gastric Acid Secretion from 1995 to 2014 in Young Japanese Healthy Volunteers under the Age of 40 Years Old

Gastric acid secretion levels are an important determinant of the manifestation of acid-related upper GI diseases such as gastroesophageal reflux disease. We recently reported that gastric acid secretion levels did not change from the 1990s to 2010s in H. pylori-negative asymptomatic Japanese outpatients with a mean age of 63 years old. However, because young people have a quite different lifestyle, including dietary pattern, from elderly people in Japan, it is worth investigating any chronologic changes in gastric acid secretion in younger generations. The aim of this analysis is to investigate the potential changes in gastric acid secretion from 1995 to 2014 in young Japanese healthy volunteers. Eighty-eight young Japanese healthy volunteers under the age of 40 with a mean age of 26 were extracted from a database accumulated from 1995 to 2014 for the present analysis. Their gastrin-stimulated gastric acid level was determined with the endoscopic gastrin test. In 76 H. pylori-negative subjects, gastric acid secretion levels showed a significant positive correlation with the calendar year when the test was performed (r = 0.27, p < 0.01). A similar trend was observed in 12 H. pylori-positive subjects. A chronological 5-year time period showed a significant positive association with gastric acid secretion in univariate and multivariate analyses (p < 0.01 and p = 0.01, respectively). Gastric acid secretion levels have been increasing in young Japanese healthy volunteers during the last 20 years. We need to monitor future trends in the prevalence of acid-related diseases such as gastro-esophageal reflux disease in Japan.

Chronic proton pump inhibition therapy in the diagnostic accuracy of serum pepsinogen I and gastrin concentrations to identify pernicious anaemia

BACKGROUND

Chronic use of proton pump inhibitors (PPIs) leads to increases in gastrin and pepsinogen-I serum concentrations.

AIM

To asses if chronic treatment with PPIs has an effect on serum gastrin and pepsinogen-I concentrations for the diagnosis of pernicious anaemia (PA).

MATERIALS AND METHODS

Serum gastrin and pepsinogen-I were measured in 38 patients with PA and 74 without PA (controls); 17/38 PA patients and 36/74 controls were treated with PPIs. Receiver Operating Curves (ROC) were used to compare diagnostic accuracy of gastrin and pepsinogen-I for PA in patients under chronic treatment with PPIs and in untreated patients.

RESULTS

PPI treatment increased pepsinogen-I in patients and in controls, while gastrin increased only in controls. In untreated patients, a pepsinogen-I <8.3ng/mL had 95.2% sensitivity and 100% specificity, whereas a gastrin >115pg/mL had 100% sensitivity and 92.11% specificity for PA diagnosis. In PPI-treated patients, a pepsinogen I<24.1ng/mL had a lower sensitivity (82.4%) but retained 100% specificity, however the best cut-off point for gastrin, 610pg/mL, had a very low sensitivity (58%).

CONCLUSIONS

PPI chronic treatment decreased the diagnostic accuracy for the studied biomarkers, particularly of gastrin. In PPI-treated patients, serum pepsinogen-I concentrations >24.1ng/mL allowed rejecting a PA diagnosis with 100% specificity.

The Diagnostic Value of Gastrin-17 Detection in Atrophic Gastritis: A Meta-Analysis

A meta-analysis was performed to assess the diagnostic value of gastrin-17 (G-17) for the early detection of chronic atrophic gastritis (CAG).An extensive literature search was performed, with the aim of selecting publications that reported the accuracy of G-17 in predicting CAG, in the following databases: PubMed, Science Direct, Web of Science, Chinese Biological Medicine, Chinese National Knowledge Infrastructure, Wanfang, and VIP. To assess the diagnostic value of G-17, the following statistics were estimated and described: sensitivity, specificity, diagnostic odds ratios (DOR), summary receiver operating characteristic curves, area under the curve (AUC), and 95% confidence intervals (CIs).Thirteen studies that met the inclusion criteria were included in this meta-analysis, comprising 894 patients and 1950 controls. The pooled sensitivity and specificity of these studies were 0.48 (95% CI: 0.45-0.51) and 0.79 (95% CI: 0.77-0.81), respectively. The DOR was 5.93 (95% CI: 2.93-11.99), and the AUC was 0.82.G-17 may have potential diagnostic value because it has good specificity and a moderate DOR and AUC for CAG. However, more studies are needed to improve the sensitivity of this diagnostic tool in the future.

Significance of Serum Pepsinogens as a Biomarker for Gastric Cancer and Atrophic Gastritis Screening: A Systematic Review and Meta-Analysis

BACKGROUND

Human pepsinogens are considered promising serological biomarkers for the screening of atrophic gastritis (AG) and gastric cancer (GC). However, there has been controversy in the literature with respect to the validity of serum pepsinogen (SPG) for the detection of GC and AG. Consequently, we conducted a systematic review and meta-analysis to assess the diagnostic accuracy of SPG in GC and AG detection.

METHODS

We searched PubMed, Embase, and the Chinese National Knowledge Infrastructure (CNKI) for correlative original studies published up to September 30, 2014. The summary sensitivity, specificity, positive diagnostic likelihood ratio (DLR+), negative diagnostic likelihood ratio (DLR-), area under the summary receiver operating characteristic curve (AUC) and diagnostic odds ratio (DOR) were used to evaluate SPG in GC and AG screening based on bivariate random effects models. The inter-study heterogeneity was evaluated by the I2 statistics and publication bias was assessed using Begg and Mazumdar's test. Meta-regression and subgroup analyses were performed to explore study heterogeneity.

RESULTS

In total, 31 studies involving 1,520 GC patients and 2,265 AG patients were included in the meta-analysis. The summary sensitivity, specificity, DLR+, DLR-, AUC and DOR for GC screening using SPG were 0.69 (95% CI: 0.60-0.76), 0.73 (95% CI: 0.62-0.82), 2.57 (95% CI: 1.82-3.62), and 0.43 (95% CI: 0.34-0.54), 0.76 (95% CI: 0.72-0.80) and 6.01 (95% CI: 3.69-9.79), respectively. For AG screening, the summary sensitivity, specificity, DLR+, DLR-, AUC and DOR were 0.69 (95% CI: 0.55-0.80), 0.88 (95% CI: 0.77-0.94), 5.80 (95% CI: 3.06-10.99), and 0.35 (95% CI: 0.24-0.51), 0.85 (95% CI: 0.82-0.88) and 16.50 (95% CI: 8.18-33.28), respectively. In subgroup analysis, the use of combination of concentration of PGI and the ratio of PGI:PGII as measurement of SPG for GC screening yielded sensitivity of 0.70 (95% CI: 0.66-0.75), specificity of 0.79 (95% CI: 0.79-0.80), DOR of 6.92 (95% CI: 4.36-11.00), and AUC of 0.78 (95% CI: 0.72-0.81), while the use of concentration of PGI yielded sensitivity of 0.55 (95% CI: 0.51-0.60), specificity of 0.79 (95% CI: 0.76-0.82), DOR of 6.88 (95% CI: 2.30-20.60), and AUC of 0.77 (95% CI: 0.73-0.92). For AG screening, the use of ratio of PGI:PGII as measurement of SPG yielded sensitivity of 0.69 (95% CI: 0.52-0.83), specificity of 0.84 (95% CI: 0.68-0.93), DOR of 11.51 (95% CI: 6.14-21.56), and AUC of 0.83 (95% CI: 0.80-0.86), the use of combination of concentration of PGI and the ratio of PGI:PGII yield sensitivity of 0.79 (95% CI: 0.72-0.85), specificity of 0.89 (95% CI: 0.85-0.93), DOR of 24.64 (95% CI: 6.95-87.37), and AUC of 0.87 (95% CI: 0.81-0.92), concurrently, the use of concentration of PGI yield sensitivity of 0.46 (95% CI: 0.38-0.54), specificity of 0.93 (95% CI: 0.91-0.95), DOR of 19.86 (95% CI: 0.86-456.91), and AUC of 0.86 (95% CI: 0.52-1.00).

CONCLUSION

SPG has great potential as a noninvasive, population-based screening tool in GC and AG screening. In addition, given the potential publication bias and high heterogeneity of the included studies, further high quality studies are required in the future.

Time series analysis of gastric acid secretion over a 20-year period in normal Japanese men

BACKGROUND

The gastric acid secretion level is an important determinant for the manifestation of the gastroesophageal reflux disease spectrum, finally leading to the development of esophageal adenocarcinoma (EAC). Although the incidence of EAC has remained low in Asia, understanding the recent trend in gastric acid secretion should be helpful in estimating future incidences of EAC in that area. We investigated the latest chronological change (1995-2014) in gastric acid secretion in normal Japanese patients.

METHODS

A total of 307 asymptomatic Japanese men who attended the clinic for annual endoscopic checkups from 1995 to 2014 were enrolled in this analysis. Gastrin-stimulated gastric acid secretion was estimated with the endoscopic gastrin test. The association between gastric acid secretion and chronological period was assessed with a multivariate linear regression analysis.

RESULTS

Overall gastric acid secretion gradually increased over the 20-year period in the entire cohort in the unadjusted analysis (p < 0.05). However, the apparent increase was largely related to the relative decreasing rate of H. pylori infection, which profoundly inhibited gastric acid secretion. Gastric acid secretion did not change over the 20-year period in H. pylori-negative subjects, and it showed only a mild increase during this period in H. pylori-positive subjects.

CONCLUSIONS

Considering that gastric acid secretion remained unchanged in H. pylori-negative Japanese men over a 20-year period at a level much lower than that in Occidental subjects, upper gastrointestinal disease profiles in the Japanese population will differ from those in Western countries in the post-H. pylori era.

Diagnostic values of serum levels of pepsinogens and gastrin-17 for screening gastritis and gastric cancer in a high risk area in northern Iran

BACKGROUND

Gastric cancer (GC) is the second cause of cancer related death in the world. It may develop by progression from its precancerous condition, called gastric atrophy (GA) due to gastritis. The aim of this study was to evaluate the accuracy of serum levels of pepsinogens (Pg) and gastrin-17 (G17) as non-invasive methods to discriminate GA or GC (GA/GC) patients.

MATERIALS AND METHODS

Subjects referred to gastrointestinal clinics of Golestan province of Iran during 2010 and 2011 were invited to participate. Serum levels of PgI, PgII and G17 were measured using a GastroPanel kit. Based on the pathological examination of endoscopic biopsy samples, subjects were classified into four groups: normal, non-atrophic gastritis, GA, and GC. Receiver operating curve (ROC) analysis was used to determine cut-off values. Indices of validity were calculated for serum markers.

RESULTS

Study groups were normal individuals (n=74), non-atrophic gastritis (n=90), GA (n=31) and GC patients (n=30). The best cut-off points for PgI, PgI/II ratio, G17 and HP were 80 μg/L, 10, 6 pmol/L, and 20 EIU, respectively. PgI could differentiate GA/GC with high accuracy (AUC=0.83; 95%CI: 0.76-0.89). The accuracy of a combination of PgI and PgI/II ratio for detecting GA/GC was also relatively high (AUC=0.78; 95%CI: 0.70-0.86).

CONCLUSIONS

Our findings suggested PgI alone as well as a combination of PgI and PgI/II ratio are valid markers to differentiate GA/GC. Therefore, Pgs may be considered in conducting GC screening programs in high-risk areas.

Identification of a high-risk group for low-dose aspirin-induced gastropathy by measuring serum pepsinogen in H. pylori-infected subjects

BACKGROUND

We recently demonstrated in humans that the extent of low-dose aspirin (LDA)-induced gastropathy was directly related to the individual gastric acid secretion level. We also established reliable cutoff serum pepsinogen (PG) values to predict gastric acid secretion status. In this study, we investigated the clinical usefulness of measuring the serum pepsinogen values for identifying a high-risk group for gastric mucosal injury among chronic LDA users.

METHODS

One hundred long-term LDA users were enrolled in this analysis. Serum from each subject was subjected to determination of H. pylori status and measurement of pepsinogen values. According to our recent report, a PG I value ≥ 50 ng/mL was defined as estimated hyperchlorhydria in H. pylori-negative subjects, while a PG I/II ≥ 3.3 was defined as estimated hyperchlorhydria in H. pylori-positive subjects. The grade of gastric mucosal injury was assessed endoscopically, and multiple logistic regression analyses were used to estimate the risk.

RESULTS

Estimated hyperchlorhydria was a strong independent risk for intensive gastric mucosal injury with an OR (95% CI): 34.0 (4.5-259) and for gastric ulcer with an OR (95% CI): 10.2 (1.8-58.3) in H. pylori-positive subjects, while it was not a significant risk in H. pylori-negative subjects. The association persisted even after excluding those with conventional risks for LDA-gastropathy such as ulcer histories.

CONCLUSION

Using simple serum measurement of H. pylori antibody and pepsinogen concentrations, an extremely high-risk group for LDA-induced gastropathy could be extracted, and these patients should become a therapeutic target for prevention of LDA-induced gastropathy.

Activation of matrix metalloproteinase-9 (MMP-9) by neurotensin promotes cell invasion and migration through ERK pathway in gastric cancer

Neurotensin (NT) is distributed throughout the brain and gastrointestinal tract. Although the relationship between NT and matrix metalloproteinase-9 (MMP-9) activity in gastric cancer has not been reported, the elevation of MMP-9 and NT is reported in the breast, lung, prostate, and gastric cancer. The aim of our study is to investigate the relationship between NT and MMP-9 activity and the underlying signaling mechanism in gastric cancer cell lines. Commercial ELISA kits were used for estimation of NT and MMP-9 expression, and fluorescence resonance energy transfer (FRET) assay was used for measurement of MMP-9 activity. Cell migration and invasion were determined by wound healing and transwell assay. The expression of signaling proteins was measured by Western blotting. Our study reveals a positive correlation between increased plasma NT and MMP-9 activity in both of patient's serum and gastric cancer cell lines. A dose-dependent elevation of MMP-9 activity was observed by NT treatment in gastric cancer cells (MKN-1 and MKN-45) compared to untreated gastric cancer and normal epithelial cell (HFE-145). Moreover, NT-mediated migration and invasion were observed in gastric cancer cells unlike in normal cell. The signaling mechanism of NT in gastric cancer cells was confirmed in protein kinase C (PKC), extracellular-signal regulated kinase (ERK), and phosphatidylinositol 3-kinase (PI3K) pathway. In addition, pretreatment of gastric cancer cells with NTR1 inhibitor SR48692 was shown to significantly inhibit the NT-mediated MMP-9 activity, cell invasion, and migration. Our finding illustrated NTR1 could be a possible therapeutic target for gastric cancer.

Low pepsinogen I level predicts multiple gastric epithelial neoplasias for endoscopic resection

Background/Aims

Synchronous/metachronous gastric epithelial neoplasias (GENs) in the remaining lesion can develop at sites other than the site of endoscopic resection. In the present study, we aimed to investigate the predictive value of serum pepsinogen for detecting multiple GENs in patients who underwent endoscopic resection.

Methods

In total, 228 patients with GEN who underwent endoscopic resection and blood collection for pepsinogen I and II determination were evaluated retrospectively.

Results

The mean period of endoscopic follow-up was 748.8±34.7 days. Synchronous GENs developed in 46 of 228 (20.1%) and metachronous GENs in 27 of 228 (10.6%) patients during the follow-up period. Multiple GENs were associated with the presence of pepsinogen I <30 ng/mL (p<0.001). Synchronous GENs were associated with the presence of pepsinogen I <30 ng/mL (p<0.001).

Conclusions

Low pepsinogen I levels predict multiple GENs after endoscopic resection, especially synchronous GENs. Cautious endoscopic examination prior to endoscopic resection to detect multiple GENs should be performed for these patients.

Cutoff serum pepsinogen values for predicting gastric acid secretion status

Measurement of the gastric acid secretion is useful for estimating the risk for various diseases in the upper gastro-intestinal tract; however, the procedure causes significant distress to the subjects. Pepsinogens I and II are secreted from the gastric fundic glands, and thus, the serum pepsinogen levels reflect the gastric functional statuses. The aim of this study is to establish appropriate serum pepsinogen cutoff points for predicting the gastric acid secretion status. In a total of 627 Japanese subjects, gastric acid secretion was measured with an endoscopic gastrin test, and the serum pepsinogen values and serum Helicobacter (H.) pylori-IgG antibody were also measured. After checking the correlation between gastric acid secretion and serum pepsinogen, the receiver operating characteristics analyses were employed for determining the most suitable cutoff points of serum pepsinogen for the gastric acid secretion status (i.e., hypochlorhydria, profound hypochlorhydria, and hyperchlorhydria). The pepsinogen I/II ratio and pepsinogen I showed the best correlation with gastric acid secretion in H. pylori-positive and H. pylori-negative subjects, respectively. The serum pepsinogen I/II ratio (or pepsinogen I in cases of H. pylori-negative subjects) was useful to determine the gastric acid secretion status with acceptable to outstanding diagnostic accuracy (the range of the area under the curve: 0.79-0.93). The diagnostic accuracy was further improved after stratifying the subjects by H. pylori-infection status. Estimating gastric acid secretion levels by simple measurement of serum pepsinogens will have significant clinical implications in estimating the risks for various diseases of the upper gastrointestinal tract.

Secondary prevention of epidemic gastric cancer in the model of Helicobacter pylori-associated gastritis

Irrespective of its etiology, long-standing, non-self-limiting gastric inflammation (mostly in Helicobacter pylori-associated cases) is the cancerization ground on which epidemic (intestinal-type) gastric carcinoma (GC) can develop. The natural history of invasive gastric adenocarcinoma encompasses gastritis, atrophic mucosal changes, and intraepithelial neoplasia (IEN). The topography, the extent and the severity of the atrophic changes significantly correlate with the risk of developing both IEN and GC. In recent years, both noninvasive (serological) tests and invasive (endoscopy/biopsy) procedures have been proposed to stratify patients according to different classes of GC risk. As a consequence, different patient-tailored GC secondary prevention strategies have been put forward. This review summarizes the histological features of H. pylori-related gastritis and the natural history of the disease. Histological and serological strategies to assess GC risk as well as the clinical management of atrophic gastritis patients are also discussed.

Serum gastrin and the pepsinogen I/II ratio as markers for diagnosis of premalignant gastric lesions

BACKGROUND

Iran is a country with very high incidences of stomach cancer, especially in Northern parts. Here we assessed prognostic value of serum screening biomarkers among people >50 years old for early detection of precancerous lesions in a hot spot for gastric carcinoma in Guilan Province, North Iran.

METHODS

A cross- sectional population-based survey was conducted on 1,390 residents of Lashtenasha city with the mean age (SD) of 61.8 (9.02) years old (50.8% females) to assess the association of gastrin and the pepsinogen (PG) I/II ratio with premalignant gastric lesions. Blood samples were taken for CBC, blood group, and serologic exams (PGI, PGII, and gastrin 17) from each subject. Expert gastroenterologists performed upper GI endoscopy and ROC curves were generated to determine appropriate cutoff points.

RESULTS

Mean values of PGI, PGII, PGI/PGII and gastrin were significantly different between patients with and without atrophy or metaplasia (P<0.05). To diagnose atrophy and intestinal metaplasia, a significantly higher AUC was observed for the PGI/PGII ratio (70 and 72%, respectively) compared to the PGI (56, 55%), PGII (63, 64%) and gastrin (59, 61%) (all p<0.001).

CONCLUSIONS

Biomarker tests such as the PGI/II ratio can be used in the screening and diagnosis of subjects at high gastric cancer risk in our region.

The association between precancerous gastric lesions and serum pepsinogens, serum gastrin, vascular endothelial growth factor, serum interleukin-1 Beta, serum toll-like receptor-4 levels and Helicobacter pylori Cag A status

BACKGROUND AND OBJECTIVE

The aim of this study was to investigate the association between serum pepsinogens, serum gastrin, serum vascular endothelial growth factor, serum interleukin-1 Beta, serum toll-like receptor-4 levels and Helicobacter pylori Cag A status in patients with various gastric precancerous lesions.

METHODS

One hundred and sixty two consecutive patients with various gastric lesions [38 (23.5%) H. pylori positive chronic non-atrophic gastritis, 45 (27.8%) autoimmune gastritis, 42 intestinal metaplasia and 37 dysplasia] were enrolled into the study. Serum pepsinogen I and II, gastrin 17, vascular endothelial growth factor, interleukin-1 Beta, toll-like receptor-4 levels, H. pylori Cag A status were evaluated.

RESULTS

H. pylori was positive in 98 (60.5%) patients and 38 of these patients were Cag A positive. Serum pepsinogen level was significantly lower in patients with autoimmune atrophic gastritis compared to the patients with non-atrophic chronic gastritis (p<0.001), intestinal metaplasia (P<0.001) and dysplasia (P=0.002). Mean serum gastrin was 1209.6±268.48 pg/mL in patients with autoimmune atrophic gastritis and 234.95±184.018 pg/mL in patients with chronic non-atrophic gastritis. Mean toll-like receptor-4 level was 0.56±0.098 ng/mL in patient with dysplasia, and this value was higher compared to patients with chronic non-atrophic gastritis (P=0.007), autoimmune atrophic gastritis (P=0.003) and intestinal metaplasia (P=0.006). Interleukin-1 Beta level was significantly lower in patients with dysplasia compared to patients with chronic non-atrophic gastritis (P=0.034).

CONCLUSIONS

Serum pepsinogens, serum gastrin and H. pylori Cag A status are important tests in detecting gastric precancerous lesions. However, toll-like receptor-4 may be a sensitive test to differentiate the patients with dysplasia from the other precancerous gastric lesions. Non-invasive tests are sensitive in the diagnosis of gastric precancerous lesions.

Gastric secretion

PURPOSE OF REVIEW

This review summarizes the past year's literature regarding the regulation of gastric exocrine and endocrine secretion, both basic science and clinical.

RECENT FINDINGS

Gastric acid secretion facilitates the digestion of protein as well as the absorption of iron, calcium, vitamin B12, and certain medications as well as prevents bacterial overgrowth, enteric infection, and possibly community-acquired pneumonia, spontaneous bacterial peritonitis, and IgE-mediated food allergy. It is regulated by neural (e.g., pituitary adenylate cyclase-activating peptide), hormonal (e.g., gastrin, ghrelin, and apelin), and paracrine (e.g., histamine) pathways as well as by chemical (e.g., amino acids) and bacterial stimuli (e.g., Helicobacter pylori). Novel peptides, which may possess physiologic function, have been identified in gastric mucosal neuroendocrine cells including parathyroid hormone-like hormone in histamine-secreting enterochromaffin-like cells and hepcidin in acid-secreting parietal cells. The secretion of hydrochloric acid by parietal cells involves translocation of the proton pump, HK-ATPase, to the apical membrane along with activation of apical chloride and potassium channels. Serum markers include chromogranin A for neuroendocrine tumors, pepsinogen I for gastric atrophy, and pepsinogen II for H. pylori infection.

SUMMARY

We continue to make progress in our understanding of the regulation of gastric acid secretion in health and disease.

CCK receptors-related signaling involved in nitric oxide production caused by gastrin 17 in porcine coronary endothelial cells

In anesthetized pigs gastrin-17 increased coronary blood flow through CCK1/CCK2 receptors and β(2)-adrenoceptors-related nitric oxide (NO) release. Since the intracellular pathway has not been investigated the purpose of this study was to examine in coronary endothelial cells the CCK1/CCK2 receptors-related signaling involved in the effects of gastrin-17 on NO release. Gastrin-17 caused a concentration-dependent increase of NO production (17.3-62.6%; p<0.05), which was augmented by CCK1/CCK2 receptors agonists (p<0.05). The effect of gastrin-17 was amplified by the adenylyl-cyclase activator and β(2)-adrenoceptors agonist (p<0.05), abolished by cAMP/PKA and β(2)-adrenoceptors and CCK1/CCK2 receptors blockers, and reduced by PLC/PKC inhibitor. Finally, Western-blot revealed the preferential involvement of PKA vs. PKC as downstream effectors of CCK1/CCK2 receptors activation leading to Akt, ERK, p38 and endothelial NOS (eNOS) phosphorylation. In conclusion, in coronary endothelial cells, gastrin-17 induced eNOS-dependent NO production through CCK1/CCK2 receptors- and β(2)-adrenoceptors-related pathway. The intracellular signaling involved a preferential PKA pathway over PKC.

Rationale in diagnosis and screening of atrophic gastritis with stomach-specific plasma biomarkers

BACKGROUND AND AIMS

Atrophic gastritis (AG) results most often from Helicobacter pylori (H. pylori) infection. AG is the most important single risk condition for gastric cancer that often leads to an acid-free or hypochlorhydric stomach. In the present paper, we suggest a rationale for noninvasive screening of AG with stomach-specific biomarkers.

METHODS

The paper summarizes a set of data on application of the biomarkers and describes how the test results could be interpreted in practice.

RESULTS

In AG of the gastric corpus and fundus, the plasma levels of pepsinogen I and/or the pepsinogen I/pepsinogen II ratio are always low. The fasting level of gastrin-17 is high in AG limited to the corpus and fundus, but low or non-elevated if the AG occurs in both antrum and corpus. A low fasting level of G-17 is a sign of antral AG or indicates high intragastric acidity. Differentiation between antral AG and high intragastric acidity can be done by assaying the plasma G-17 before and after protein stimulation, or before and after administration of the proton pump inhibitors (PPI). Amidated G-17 will rise if the antral mucosa is normal in structure. H. pylori antibodies are a reliable indicator of helicobacter infection, even in patients with AG and hypochlorhydria.

CONCLUSIONS

Stomach-specific biomarkers provide information about the stomach health and about the function of stomach mucosa and are a noninvasive tool for diagnosis and screening of AG and acid-free stomach.

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.

The intriguing relationship of Helicobacter pylori infection and acid secretion in peptic ulcer disease and gastric cancer

Helicobacter pylori infection induces chronic inflammation of the gastric mucosa and thus profoundly affects gastric physiology. In the acute phase of infection, gastric acid secretion is transiently impaired. The morphological damage of the gastric mucosa, changes in gastric hormone release, and disruption of neural pathways all contribute to influence gastric acid secretion in a distinct manner. Changes in gastric acid secretion, whether impaired or increased, are intimately related with the topographic phenotypes of gastritis and the presence of atrophy or absence of corpus atrophy. The interplay of gastritis phenotype and acid secretion are key determinants in disease outcomes. Corpus-predominant gastritis and corpus atrophy are accompanied by hypochlorhydria and carry the highest risk for gastric cancer, whereas antrum-predominant gastritis with little involvement of the corpus-fundic mucosa is associated with hyperchlorhydria and predisposes to duodenal ulcer disease.