Serum pepsinogen concentrations as a measure of gastric acid secretion in Helicobacter pylori-negative and -positive Japanese subjects

Reference Ranges and Comparison of Pepsinogen by Chemiluminescence Immunoassay and Enzyme-Linked Immunosorbent Assay in Chinese Population

Objective

Serum pepsinogen (PG) is a good indicator of atrophic changes in the gastric mucosa. Gastric mucosal atrophy is a high-risk factor for gastric cancer. Serological testing for PG combined with endoscopy can help to improve gastric cancer screening. In this study, we established the reference ranges of serum PG-I, PG-II, and the PG-I/II ratio (PGR) in the Chinese population by chemiluminescence immunoassay (CLIA) and enzyme-linked immunosorbent assay (ELISA). Besides, in the real world, doctors are often confused by the results of different testing platforms. Thus, a comparison of methods CLIA and ELISA was performed.

Methods

2904 individuals were enrolled from six regions in China as part of the Chinese Adult Digestive Diseases Surveillance (2016) program. The individuals completed questionnaires and volunteered to undergo examinations, including gastroscopy, urea breath test, abdominal ultrasound examination and routine serologic tests. Serum was collected to measure PGs (including PG-I, PG-II and PGR) by CLIA and ELISA. Participants who were found obvious abnormalities or absent from the examinations were excluded. Ultimately, 747 healthy individuals were enrolled in this study. The Kolmogorov-Smirnov test was used to assess the distribution of variables. The Kruskal-Wallis H or Mann-Whitney U-tests were used to compare different sex, age, and geographical groups. The 95% reference ranges of PGs obtained by the two methods were established according to document CLSI-EP28-A3, with covariates of sex, age, and region. Spearman correlation analysis, linear regression analysis and allowable total error (ATE) zone analysis were utilized for comparing the two methods.

Results

On overall, the 95% reference ranges of PG-I, PG-II, and PGR measured by CLIA were 23.00-110.64 ng/mL, 2.50-19.13 ng/mL, and 3.87-13.30, respectively. Meanwhile, the reference ranges of PG-I, PG-II, and PGR measured by ELISA were 36.93-205.06 ng/mL, 1.65-17.96 ng/mL, and 7.50-33.60, respectively. Both PG-I and PG-II levels measured by the two platforms were found to be influenced by sex and age. PGR measured by CLIA was influenced by age but not by sex, while PGR measured by ELISA was not affected by either age or sex. Regional factors did not significantly impact the PG results, except for PG-I detected by ELISA. Ultimately, reference ranges for PGs were established based on age and sex stratification. Additionally, the Spearman correlation analysis revealed that the correlation coefficients for PG-I, PG-II, and PGR detected by the two methods were 0.899, 0.887, and 0.777, respectively, indicating a strong correlation between the two methods. The regression equation for the PG levels detected by two methods was obtained through linear regression analysis. The ATE analysis provided a visual depiction of the consistency between the two methods, clearly indicating the poor agreement between them.

Conclusion

This study established the reference ranges of PGs by strict and intact enrollment standard. In addition, the results indicated a strong linear relationship between the two methods, yet with a clear bias, which was valuable for laboratory interpretation.

Useful Serum Pepsinogen Levels for Detecting Ongoing Helicobacter pylori Infection in Asymptomatic Subjects: A Cross-Sectional Study Based on 13C-urea Breath Test Findings

BACKGROUND /AIMS

The serum pepsinogen (PG) assay is used to screen subjects at high risk for gastric cancer. Currently, there are few studies on the PG levels for the detection of Helicobacter pylori infection. This study aimed to determine the PG assay findings for detecting ongoing infection.

METHODS

Asymptomatic subjects who underwent a ¹³C-urea breath test (¹³C-UBT) on the day of gastroscopy and serum assay for cancer screening were included. Subjects with a recent intake of acid suppressants or antibiotics, gastrectomy, or renal failure were excluded. H. pylori infection was defined as a positive ¹³C-UBT result.

RESULTS

Among the 500 included subjects, 167 (33.4%) had current infection. The serum PG II levels of > 12.95 ng/mL (area under the curve [AUC] = 0.930, sensitivity 86.5%, specificity 90.7%) and PG I/II ratios of < 4.35 (AUC = 0.875, sensitivity 86.8%, specificity 79.6%) were related to infection. The PG I/II ratios were inversely correlated with age (r = -0.160, p = 0.039). The cutoff values of PG I/II ratios were lower in older subjects aged ≥ 50 years (< 4.05; AUC = 0.875, sensitivity 80.7%, specificity 88.2%) than in younger subjects aged < 50 years (< 4.35; AUC = 0.873, sensitivity 77.4%, specificity 88.9%).

CONCLUSIONS

Serum PG II levels > 12.95 ng/mL and PG I/II ratios < 4.35 suggest ongoing infection in asymptomatic subjects; therefore, H. pylori confirmation tests (i.e., ¹³C-UBT) should be considered under these conditions. Stricter criteria are required in older subjects aged ≥ 50 years (PG I/II ratio < 4.05) to detect ongoing infection than younger subjects.

Serum Assay Findings after Successful Helicobacter pylori Eradication

Serum pepsinogen (PG), anti-Helicobacter pylori (H. pylori) immunoglobulin G (IgG), and gastrin-17 (G-17) are plasma biomarkers for gastritis. H. pylori serology titers and PG levels increase during active H. pylori infection; moreover, elevated PG II levels indicate a high risk for diffuse-type gastric cancer in East Asian populations. Serum PG I/II ratios and PG I levels decrease with the progression of gastric corpus atrophy; thus, a combination of serum PG I levels ≤70 ng/mL and a PG I/II ratio ≤3 (serologic atrophy) indicates a high risk of intestinal-type gastric cancer. Serum G-17 is often not used as an indicator in H. pylori-seroprevalent populations because it is usually elevated in subjects with H. pylori infections. When H. pylori is eradicated, most patients show a rapid decrease in serum PG II levels and anti-H. pylori IgG titers within a few months. Seroreversion is required for several months to years after regression of H. pylori. Moreover, seroreversion may not always be achieved in all eradicated cases. The serum PG I/II ratio starts to increase after eradication; therefore, serologic atrophy improves accordingly, unless severe atrophy is present. Thus, some eradicated patients may show normal serum assay findings but have a higher risk for developing gastric cancer than H. pylori-naive subjects. Furthermore, serum PG levels decrease after gastrectomy and increase with the intake of certain drugs (e.g., aspirin or acid suppressants) or in renal failure patients. Due to such wide variations, serum assays are inadequate for the confirmation of H. pylori eradication. It is useful when interpreted with gastroscopy and other H. pylori test findings.

Efficacy of acotiamide on postprandial distress syndrome and epigastric pain syndrome depending on the estimated gastric acid secretion level

Background/Aims

Gastric acid secretion is suspected to be a pivotal contributor to the pathogenesis of functional dyspepsia. The present study investigates the potential association of the gastric acid secretion estimated by measuring serum pepsinogen with therapeutic responsiveness to the prokinetic drug acotiamide.

Methods

Dyspeptic patients consulting participating clinics from October 2017 to March 2019 were prospectively enrolled in the study. The dyspeptic symptoms were classified into postprandial distress syndrome (PDS) and epigastric pain syndrome (EPS). Gastric acid secretion levels were estimated by the Helicobacter pylori infection status and serum pepsinogen using established criteria and classified into hypo-, normo-, and hyper-secretion. Each patient was then administered 100 mg acotiamide thrice daily for 4 weeks, and the response rate to the treatment was evaluated using the overall treatment efficacy scale.

Results

Of the 86 enrolled patients, 56 (65.1%) and 26 (30.2%) were classified into PDS and EPS, respectively. The estimated gastric acid secretion was not significantly different between PDS and EPS. The response rates were 66.0% for PDS and 73.1% for EPS, showing no significant difference. While the response rates were stable, ranging from 61.0% to 75.0% regardless of the estimated gastric acid secretion level among subjects with PDF, the rates were significantly lower in hyper-secretors than in non-hyper-secretors among subjects with EPS (42.0% vs 83.0%, P = 0.046).

Conclusion

Although acotiamide is effective for treating EPS as well as PDS overall, the efficacy is somewhat limited in EPS with gastric acid hyper-secretion, with gastric acid suppressants, such as proton pump inhibitors, being more suitable.

HELICOBACTER PYLORI CHRONIC GASTRITIS ON PATIENTS WITH PREMALIGNANT CONDITIONS: OLGA AND OLGIM EVALUATION AND SERUM BIOMARKERS PERFORMANCE

BACKGROUND

H. pylori chronic atrophic gastritis is a premalignant lesion, and its staging, according to OLGA and OLGIM systems aims to identify patients at increased risk of developing gastric cancer and optimize their follow-up. GastroPanel®, serum biomarkers panel including pepsinogen I (PGI), pepsinogen II (PGII), Gastrin 17 (G17) and anti- H. pylori antibodies is a noninvasive test for adenocarcinoma risk assessment in chronic H. pylori gastritis patients.

OBJECTIVE

Prospective study to evaluate the concordance between OLGA and OLGIM grading systems, as well as to evaluate GastroPanel´s performance in patients with premalignant lesions secondary to H. pylori chronic gastritis in Brazil.

METHODS

Patients with H. pylori chronic gastritis with premalignant lesions confirmed by histology were recruited from the gastrointestinal clinic of a University Hospital. All participants underwent endoscopic examination with biopsies which were reported according to updated Sydney system and premalignant lesions grading systems (OLGA and OLGIM). Blood samples were collected for biomarkers serological analysis (GastroPanel®, Biohit, Helsinki, Finland). The cut off values used to define high risk patients were those recommended by the manufacturer: PGI ≤30 µm/L and PGI/PGII ≤3.

RESULTS

41 patients were recruited: 28 women, 13 men, mean age 67.3 (47-89, SD: 9.6) years. By OLGA system, were obtained: OLGA 0 (n=1), OLGA I (n=7), OLGA II (n=17), OLGA III (n=9), and OLGA IV (n=7). By OLGIM system, were obtained: OLGIM 0 (n=14), OLGIM I (n=5), OLGIM II (n=10), OLGIM III (n=10), and OLGIM IV (n=2). Regarding histological staging among patients staged as low risk (OLGA/OLGIM 0, I and II) and high risk (OLGA/OLGIM III and IV) for gastric cancer development, the concordance rate found between both classifications was 85.4%. Considering high risk patients, those patients thus included in at least one of the systems the final distribution of our sample considered 24 low-risk and 17 high-risk patients for the development of gastric cancer. To determine by GastroPanel® whether the patient would be at low or high risk of developing gastric cancer, PGI showed a sensitivity, specificity and accuracy of 0.47 (95%CI: 0.26-0.69), 0.67 (95%CI: 0.47-0.82), and 0.58 (95%CI: 0.43-0.72), respectively, while PGI/PGII showed sensitivity, specificity and accuracy of 0.06 (95%CI: 0.01-0.27), 0.83 (95%CI: 0.64-0.93) and 0.51 (95%CI: 0.36-0.66), respectively.

CONCLUSION

The histological classifications OLGA and OLGIM presented a substantial concordance rate among themselves. Simultaneous use of both histological classification systems increased the identification's rate of high-risk patients. Biomarker analysis was not effective to distinguish low to high risk patients in the studied population. Further studies are needed to validate its use in clinical practice in Brazil.

Early detection of gastric cancer beyond endoscopy - new methods

Early detection of gastric cancer is remaining a challenge. This review summarizes current knowledge on non-invasive methods that could be used for the purpose. The role of traditional cancer markers such as CEA, CA 72-4, CA 19-9, CA 15-3, and CA 12-5 lies mainly in therapy monitoring than early detection. Most extensive studied biomarkers (pepsinogens, ABC method) are aiming at the detection of precancerous lesions with modest sensitivity for cancer. Tests based on the detection of cancer-specific methylation patterns (PanSeer), circulating proteins and mutations in circulating tumour DNA (CancerSEEK), as well as miRNA panels have demonstrated promising results bringing those closer to practice. More extensive research is required before tests based on the detection of circulating tumour cells, extracellular vesicles and cell-free RNA could reach the practice. Detection of volatile organic compounds in the human breath is a promising development; sensor technologies for this purpose could be very attractive in screening settings.

Serum Gastrin Predicts Hydrogen-Producing Small Intestinal Bacterial Overgrowth in Patients With Abdominal Surgery: A Prospective Study

OBJECTIVES

Small intestinal bacterial overgrowth (SIBO) might be associated with a history of abdominal surgery. We aimed to evaluate the prevalence of SIBO and to investigate serum gastrin and pepsinogen as predictors of SIBO in patients with a history of hysterectomy, gastrectomy, or cholecystectomy.

METHODS

This prospective study surveyed 146 patients with a history of hysterectomy, gastrectomy, or cholecystectomy, and 30 healthy controls, who underwent a hydrogen (H2)-methane (CH4) glucose breath test (GBT) for SIBO. Serum pepsinogen I and II and gastrin levels were reviewed.

RESULTS

GBT positivity (+) was significantly higher in patients with histories of abdominal surgery than that in in controls (37.6% vs 13.3%, P < 0.01). Among GBT+ patients, 36.0% (18/50), 96.2% (25/26), and 17.1% (12/70) were in the hysterectomy, gastrectomy, and cholecystectomy groups, respectively. Among the GBT subtypes, 43.6% (24/55), 10.9% (6/55), and 45.5% (25/55) of patients were in the GBT(H2)+, GBT(CH4)+, and GBT(mixed)+ groups, respectively. The gastrectomy group had significantly more GBT+ or GBT(H2)+ patients than the other surgical groups. Gastrin levels were higher in GBT(H2)+ patients and lower in GBT(CH4)+ patients than those in GBT- patients. Previous gastrectomy and elevated gastrin levels were independent predictive factors of GBT(H2)+.

DISCUSSION

SIBO is not uncommon in patients with histories of abdominal surgeries, but it is more common in patients who have undergone gastrectomy. Serum gastrin level could be a serologic predictor of H2-producing SIBO. The relationship between serum gastrin and SIBO requires further research.

Endoscopic Characteristics of Rugal Hyperplasia and Related Acid Condition in Helicobacter pylori-Infected Stomach

Background/Aims

Rugal hyperplastic gastritis (RHG) is associated with Lauren’s diffuse-type gastric cancer (GC) and the accompanying active inflammation is linked to gastric hypoacidity. We tried to establish the steps for identifying high-risk GC patients.

Methods

We included 196 patients with confirmed Helicobacter pylori infection by rapid urease test during screening endoscopy for health check-up from January 2016 to September 2016; all patients underwent blood tests for pepsinogen I and II and fasting serum gastrin. We compared RHG findings with various other endoscopic mucosal images. We also evaluated the relationships between RHG and other mucosal aspects for a given acid status based on serological markers.

Results

Hypoacid and ultra-low-acid (67%) statuses were dominant, with only 18% hyperacid patients. RHG with high acid was related to a less atrophic body type (p=0.001), and RHG with ultra-low acid was associated with body xanthoma (p=0.029) and increased serum gastrin level (p=0.038). However, RHG’s influence on gastric acidity was only seen in closed-type endoscopic atrophic border (EAB), not in open type (p=0.001).

Conclusions

The majority of RHG patients had hypoacid status. RHG frequency showed no difference between closed and opentype EAB, but gastric acidity was influenced by RHG only in closed-type EAB.

Effect of acid-reducing agents on clinical relapse in ulcerative colitis with pH-dependent-released 5-aminosalicylic acid: a multicenter retrospective study in Japan

BACKGROUND/AIMS

5-Aminosalicylic acid (5-ASA) is a basic drug for inducing and maintaining remission for ulcerative colitis. One of its formulations has a coating with a pH-dependent degradation that ensures the release 5-ASA at the terminal ileum. No evidence has been shown concerning the effects of proton pump inhibitors (PPIs) or H2 receptor antagonists (H2RAs) on the clinical course of ulcerative colitis patients in remission. The present study assessed the effect of PPIs or H2RAs on the relapse of ulcerative colitis patients in clinical remission maintained by pH-dependent released 5-ASA.

METHODS

Ulcerative colitis patients who had been prescribed time- or pH-dependent-released 5-ASA between January 2015 and December 2018 were enrolled in this multicenter retrospective study. The period of remission until relapse occurred was analyzed among the patients taking time-dependent-released 5-ASA or pH-dependent-released 5-ASA with/without PPIs or H2RAs.

RESULTS

One hundred and nineteen patients were analyzed in this study. In the primary endpoint, the relapse rate was higher in patients taking pH-dependent-released 5-ASA and PPIs or H2RAs than in those taking the pH-dependent-released 5-ASA without PPIs or H2RAs, while the relapse rate was similar in patients taking the time-dependent-released 5-ASA with or without PPIs or H2RAs concomitantly. Patients with a short duration of disease and middle-aged patients more frequently showed relapse with PPIs or H2RAs than the other patients.

CONCLUSIONS

The coadministration of PPIs or H2RAs affects the clinical course of ulcerative colitis in remission maintained by pH-dependent-released 5-ASA.

Analysis of factors associated with recovery of the serum pepsinogen ratio after Helicobacter pylori eradication: a long-term follow-up study in Korea

Objective: Serum levels of pepsinogen (PG) are related to Helicobacter pylori-induced inflammation of the gastric mucosa. This study aimed to examine the influence of H. pylori eradication on serum PG, analyze its associated factors, and evaluate the long-term outcomes.Methods: H. pylori-positive patients who underwent gastroscopy and serum PG measurement were enrolled in a single academic hospital. After H. pylori eradication, the measurement of serum PG level was performed. Recovery of serum PG I/II ratio was defined as a PG I/II ratio after eradication of >3.0 in patients with a PG I/II ratio ≤ 3.0 before eradication. Follow-up involved serum PG measurement and gastroscopy with a rapid urease test annually.Results: In all, 327 patients were eligible for study inclusion. Compared to those before H. pylori eradication, serum PG I (74.9 vs. 44.3 ng/mL, p < .001) and PG II (25.4 vs. 9.1 ng/mL, p < .001) levels significantly decreased after successful eradication. In addition, there was a significant increase in serum PG I/II ratio after eradication (3.07 vs. 4.98, p < .001). In multivariate analyses, the following were independently associated with failed recovery of serum PG I/II ratio despite successful eradication: age ≥ 60 years (odds ratio [OR] = 0.231, 95% confidence interval [CI] = 0.084-0.629, p = .004) and severe gastric atrophy (OR = 0.156, 95% CI = 0.055-0.440, p < .001).Conclusions: Recovery of serum PG I/II ratio after H. pylori eradication may be achieved in H. pylori-infected patients aged <60 years without severe gastric atrophy.

Impact of Helicobacter pylori Infection on Gastric Variceal Bleeding among Patients with Liver Cirrhosis

BACKGROUND AND AIMS

Currently, it is well known that Helicobacter pylori- (H. pylori-) related peptic ulcer is one of the main causes of nonvariceal bleeding in cirrhotic patients. However, there is a lack of data to identify the exact effect of H. pylori infection on variceal bleeding. This study was conducted to identify the impact of H. pylori infection on gastric variceal bleeding in cirrhotic patients.

PATIENTS AND METHODS

76 cirrhotic patients with gastric varices were included in this prospective study and divided into 2 groups: nonbleeding gastric varices (32 patients) and bleeding gastric varices (44 patients). The fasting serum gastrin level was measured. Mucosal biopsies from the gastric body and antrum were examined to determine the patterns of gastritis and the presence of H. pylori.

RESULTS

The frequency of H. pylori infection in the studied patients was 59.2%. There were significant differences between both groups regarding liver decompensation (P = 0.001), red color sign over gastric varices (P = 0.0011), prevalence of H. pylori infection (P = 0.0049), histological patterns of gastritis (P = 0.0069), and serum gastrin level (P = 0.0200). By multivariate analysis, Child C cirrhosis, red color sign over gastric varices, and H. pylori-induced follicular gastritis were independent risk factors for bleeding from gastric varices.

CONCLUSION

H. pylori-induced follicular gastritis is considered as an additional risk factor for bleeding from gastric varices.

The histologic detection of Helicobacter pylori in seropositive subjects is affected by pathology and secretory ability of the stomach

BACKGROUND

Helicobacter pylori is unevenly distributed in hypochlorhydric environments. The study aim was to elucidate the risk factors for a negative Giemsa staining finding in seropositive subjects by measuring the secretory ability of the stomach.

METHODS

Subjects aged over 18 years were included consecutively after endoscopic biopsy at gastric lesions with color or structural changes. Blood was sampled for the serum pepsinogen (PG) assay and H. pylori serology test. After excluding the subjects with past H. pylori eradication, the risk factors for a negative Giemsa staining finding in seropositive subjects were analyzed.

RESULTS

Among 872 included subjects, a discrepancy between the serum anti-H. pylori IgG and Giemsa staining findings was found in 158 (18.1%) subjects, including 145 Giemsa-negative, seropositive subjects. Gastric adenocarcinoma/adenoma (OR = 11.090, 95% CI = 3.490-35.236) and low serum PG II level (OR = 0.931, 95% CI = 0.899-0.963) were the independent risk factors for a negative Giemsa staining finding in seropositive subjects. The cutoff value of serum PG II level was 7.45 ng/mL (area under curve [AUC] = 0.904, 95% CI = 0.881-0.927). Follow-up studies of Giemsa staining at different sites of the stomach revealed that 75% of the Giemsa-negative seropositive subjects with adenocarcinoma are positive, whereas none of those with low serum PG II level of <7.45 ng/mL revealed positive findings.

CONCLUSIONS

The risk of a negative Giemsa staining finding in seropositive subjects is increased in gastric adenocarcinoma/adenoma specimens and in subjects with a diminished gastric secretory ability with low serum PG II level of <7.45 ng/mL. A false-negative Giemsa staining finding is common in subjects with adenocarcinoma, and therefore, additional biopsies at different sites should be performed in these subjects.

IVTH BRAZILIAN CONSENSUS CONFERENCE ON HELICOBACTER PYLORI INFECTION

ABSTRACT Significant progress has been obtained since the III Brazilian Consensus Conference on H. pylori infection held in 2012, in Bento Gonçalves, Brazil, and justify a fourth meeting to establish updated guidelines on the current management of H. pylori infection. Therefore, the Núcleo Brasileiro para Estudo do Helicobacter pylori e Microbiota (NBEHPM), association linked to Brazilian Federation of Gastroenterology (FBG) held its fourth meeting again in Bento Gonçalves, RS, Brazil, on August 25-27, 2017. Twenty-six delegates, including gastroenterologists, endoscopists, and pathologists from the five regions of Brazil as well as one international guest from the United States, participated in the meeting. The participants were invited based on their knowledge and contribution to the study of H. pylori infection. The meeting sought to review different aspects of treatment for infection; establish a correlation between infection, dyspepsia, intestinal microbiota changes, and other disorders with a special emphasis on gastric cancer; and reassess the epidemiological and diagnostic aspects of H. pylori infection. Participants were allocated into four groups as follows: 1) Epidemiology and Diagnosis, 2) Dyspepsia, intestinal microbiota and other afections, 3) Gastric Cancer, and, 4) Treatment. Before the consensus meeting, participants received a topic to be discussed and prepared a document containing a recent literature review and statements that should be discussed and eventually modified during the face-to-face meeting. All statements were evaluated in two rounds of voting. Initially, each participant discussed the document and statements with his group for possible modifications and voting. Subsequently, during a second voting in a plenary session in the presence of all participants, the statements were voted upon and eventually modified. The participants could vote using five alternatives: 1) strongly agree; 2) partially agree; 3) undecided; 4) disagree; and 5) strongly disagree. The adopted consensus index was that 80% of the participants responded that they strongly or partially agreed with each statement. The recommendations reported are intended to provide the most current and relevant evidences to management of H. pylori infection in adult population in Brazil.

Gastric cancer and Hedgehog signaling pathway: emerging new paradigms

Ever since its initial discovery in Drosophila, hedgehog signaling has been linked to foregut development, The mammalian genome expresses three Hedgehog paralogues, sonic hedgehog (Shh), Indian Hedgehog, and desert hedgehog. In the mucosa of the embryonic and adult foregut, Shh expression is the highest. It has now become clear that hedgehog signaling is of pivotal importance in gastric homeostasis. Aberrant activation of hedgehog signaling is associated with a range of pathological consequences including various cancers. Also in gastric cancer, clinical and preclinical data support a role of Hedgehog signaling in neoplastic transformation, and gastrointestinal cancer development, also through cancer stroma interaction. Technological advance are facilitating monitoring Hedgehog signaling broadening options for the more efficient screening of individuals predisposed to eventually developing gastric cancer and targeting Hedgehog signaling may provide opportunities for prophylactic therapy once atrophic gastritis develops. Nevertheless, convincing evidence that Hedgehog antagonists are of clinically useful in the context of gastric cancer is still conspicuously lacking. Here we analyze review the role of Hedgehog in gastric physiology and the potential usefulness of targeting Hedgehog signaling in gastric cancer.

Detection of gastric atrophy by circulating pepsinogens: A comparison of three assays

BACKGROUND

Circulating levels of pepsinogens have been used in high gastric cancer-risk Asian and European populations to triage endoscopic evaluation for more severe pathology. There are different analytic methods with uncertain correlations. We therefore compared diagnostic performance of three commonly used pepsinogen assays to detect histologically confirmed gastric atrophy.

METHODS

We tested plasma samples from adult patients with (n=50) and without (n=755) moderate or severe gastric corpus atrophy, as determined histologically by consensus of three expert pathologists. A single laboratory measured pepsinogens I (PgI) and II (PgII) using commercially available assays: two ELISA assays produced by Biohit (Finland) and Vector Best (Russia), and a latex agglutination assay from Eiken (Japan). Quantitative correlations were assessed by Spearman statistics. Receiver operating characteristic (ROC) curves vs histological diagnosis were calculated using both the manufacturers' and optimized cutoffs.

RESULTS

Pepsinogen levels were highly correlated among the assays (pairwise Rhos: PgI≥0.84, PgII≥0.87; all P-values<.01). Based on manufacturers' cutoffs, sensitivities, specificities and areas under the ROC curve for detecting moderate to severe histological corpus atrophy by PgI/PgII were 44%/91%/0.70, 56%/84%/0.76, and 52%/90%/0.77 for Biohit, Vector Best and Eiken, respectively. Cutoffs optimized by ROC or data mining analyses did not substantially improve test performance.

CONCLUSIONS

Commercial assays for pepsinogen have good relative agreement but are imperfect tests for clinical diagnosis of gastric atrophy.

IMPACT

Pepsinogen testing alone does not provide sufficient information for gastric cancer risk stratification. Future investigations should focus on other potential markers, in combination with pepsinogens.

High Serum Pepsinogen I and beta Helicobacter pylori Infection Are Risk Factors for Aspirin-Induced Gastroduodenal Injury

BACKGROUND

Whether gastric hyperchlorhydria and Helicobacter pylori infection contribute to aspirin-induced gastroduodenal injury still lacks evidence. Because serum pepsinogens (PGs) and gastrin-17 (G17) can reflect gastric acid secretion, this study intended to elucidate whether serum PGs, serum G17, and H. pylori infection are associated with aspirin-induced gastrointestinal injury.

SUMMARY

A total of 60 patients taking low-dose aspirin for more than 1 month were enrolled in this study. Serum PG I, PG II, and G17 were determined using ELISA. A 14C-urea breath test was used for the detection of an H. pylori infection. The modified Lanza score was used to evaluate the degree of gastroduodenal injury under endoscopy. The median serum PG I level was significantly higher in the intensive gastroduodenal injury (IGI) group compared to that in the mild gastroduodenal injury group (155.0 vs. 116.6 ng/mL, p = 0.006). The H. pylori infection rate was significantly higher in the IGI group (73 vs. 40%, p = 0.037). Receiver operator characteristic curves analysis revealed that the cutoff value of PG I was 123 ng/mL, with 80% sensitivity and 61.4% specificity. H. pylori infection combined with PG I at >123 ng/mL had an OR (95% CI) of 15.8 (2.4 ± 104.5) for the prediction of aspirin-induced gastroduodenal injury. Key Messages: Serum PG I and H. pylori infection could be used to identify potential high-risk aspirin-induced gastroduodenal injury patients.

Factors Related to Upper Gastrointestinal Symptom Generation in 2275 Helicobacter pylori Seroprevalent Adults

BACKGROUND AND AIM

Upper gastrointestinal (UGI) symptoms are common; however, the role of Helicobacter pylori and gastric corpus atrophy in the generation of these symptoms is controversial. The aim of this study was to determine the risk factors for UGI symptoms in adults in an endemic area of H. pylori infection.

METHODS

Korean adults who completed questionnaires on the day of serum anti-H. pylori IgG and pepsinogen (PG) assays before UGI endoscopy were included. Gastric corpus atrophy was based on the criteria of a serum PG I/II ratio <3.0 and a PG I <70 ng/ml.

RESULTS

Of the 2275 included subjects, 723 (31.8%) had at least one UGI symptom. A total of 374 (16.4%) subjects had multiple symptoms without significant correlations between the symptoms (λ < 0.2). The H. pylori serology assay was positive in 1382 (60.7%) subjects, and gastric corpus atrophy was present in 291 (12.8%). Neither H. pylori seropositivity (p = 0.077) nor gastric corpus atrophy (p = 0.138) was related to the presence of UGI symptoms. Female gender and smoking were independent risk factors for heartburn and upper abdominal pain (all p < 0.001). Furthermore, female gender was the only independent risk factor for multiple UGI symptoms (p < 0.001), globus sensation (p < 0.001), early satiety (p < 0.001), epigastric soreness (p = 0.001), and chest discomfort (p = 0.003).

CONCLUSIONS

In an H. pylori seroprevalent population, female gender is the most common risk factor followed by smoking for UGI symptom generation. Neither H. pylori seropositivity nor gastric corpus atrophy is an independent risk factor for UGI symptom generation.

Hedgehog Signaling Links Chronic Inflammation to Gastric Cancer Precursor Lesions

Since its initial discovery in Drosophila, Hedgehog (HH) signaling has long been associated with foregut development. The mammalian genome expresses 3 HH ligands, with sonic hedgehog (SHH) levels highest in the mucosa of the embryonic foregut. More recently, interest in the pathway has shifted to improving our understanding of its role in gastrointestinal cancers. The use of reporter mice proved instrumental in our ability to probe the expression pattern of SHH ligand and the cell types responding to canonical HH signaling during homeostasis, inflammation, and neoplastic transformation. SHH is highly expressed in parietal cells and is required for these cells to produce gastric acid. Furthermore, myofibroblasts are the predominant cell type responding to HH ligand in the uninfected stomach. Chronic infection caused by Helicobacter pylori and associated inflammation induces parietal cell atrophy and the expansion of metaplastic cell types, a precursor to gastric cancer in human subjects. During Helicobacter infection in mice, canonical HH signaling is required for inflammatory cells to be recruited from the bone marrow to the stomach and for metaplastic development. Specifically, polarization of the invading myeloid cells to myeloid-derived suppressor cells requires the HH-regulated transcription factor GLI1, thereby creating a microenvironment favoring wound healing and neoplastic transformation. In mice, GLI1 mediates the phenotypic shift to gastric myeloid-derived suppressor cells by directly inducing Schlafen 4 (slfn4). However, the human homologs of SLFN4, designated SLFN5 and SLFN12L, also correlate with intestinal metaplasia and could be used as biomarkers to predict the subset of individuals who might progress to gastric cancer and benefit from treatment with HH antagonists.

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.

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.

Helicobacter pylori infection affects immune responses following vaccination of typhoid-naive U.S. adults with attenuated Salmonella typhi oral vaccine CVD 908-htrA

BACKGROUND

 We examined the association between Helicobacter pylori infection and the immune response following oral immunization of US adults with attenuated Salmonella Typhi vaccine CVD 908-htrA.

METHODS

 Baseline sera from 74 volunteers without a history of typhoid fever who were immunized orally with CVD 908-htrA were tested by enzyme-linked immunosorbent assay for immunoglobin G (IgG) antibodies to H. pylori, hepatitis A antibodies (a marker of low socioeconomic status and exposure to enteric infections), and pepsinogen (PG) I and II levels (measures of gastric inflammation). IgG against S. Typhi lipopolysaccharide (LPS) O and flagella was measured before and 28 days following immunization; a ≥4-fold increase in titer from baseline constituted seroconversion.

RESULTS

 Seroconversion of S. Typhi IgG LPS antibodies was significantly higher among vaccinees infected with H. pylori versus uninfected subjects: adjusted odds ratio (OR) 3.8, 95% confidence interval (CI), 1.1-12.6 (P = .03). A low PG I:PG II ratio (<5), indicating more advanced corpus gastritis, increased the odds of seroconversion of IgG S. Typhi flagella antibody (adjusted OR 6.4, 95% CI, 1.3-31.4; P = .02). Hepatitis A infection did not influence the immune response to CVD 908-htrA.

CONCLUSIONS

 H. pylori infection and gastric inflammation may enhance humoral immunity to oral attenuated S. Typhi vaccine.

Effect of Helicobacter pylori infection on esophagogastric variceal bleeding in patients with liver cirrhosis and portal hypertension

BACKGROUND AND AIMS

Bleeding from esophageal and gastric varices is a fatal event in patients with liver cirrhosis and portal hypertension. However, the effects of Helicobacter pylori (H. pylori) infection on esophagogastric variceal bleeding are not known. The present study was aimed to elucidate the role of H. pylori infection in esophagogastric variceal bleeding.

METHODS

The subjects were 196 cirrhotic patients who were admitted to the Kurume University Hospital to treat their esophagogastric varices consisted of 95 with acute bleeding and 101 with nonbleeding but high risk of bleeding. For the diagnosis of H. pylori infection, a (13) C-urea breath test was used, and serum pepsinogen (PG) I and II levels and the PG I/II ratio were also measured.

RESULTS

Esophagogastric variceal bleeding was seen in 34.9% (n = 30) of the H. pylori-infected patients (n = 86) and in 59.1% (n = 65) of the noninfected patients (n = 110) (P < 0.0007). There was no significant difference in the infection rate between the bleeding sites of the esophagus and the stomach. The serum PG I and II levels and the PG I/II ratio were 65.6 ng/dL, 14.7 ng/dL, and 4.4, respectively, for the bleeding patients (n = 95), and 43.7 ng/dL, 17.7 ng/dL, and 3.1 for the nonbleeding patients (n = 101). Thus, the nonbleeding patients had significantly higher rate of H. pylori infection and lower acid secretion than bleeding patients (0.001). In addition, multivariate logistic regression analysis showed a significant negative association between H. pylori infection and esophagogastric variceal bleeding.

CONCLUSIONS

These results suggest that H. pylori infection has a protective effect against esophagogastric variceal bleeding through the induction of gastric mucosal atrophy and concomitant hypoacidity.

Review article: methods of measuring gastric acid secretion

BACKGROUND

Gastric acid has an important pathophysiological role in human beings. Numerous methods have been evaluated over the years in an attempt to measure gastric acid and stomach acidity, to study the role of gastric acid in gastrointestinal diseases in humans and to evaluate the effects of acid suppressing drugs.

AIM

To review methods that have been used to measure gastric acid and gastric acidity.

METHODS

Searches of the electronic databases PUBMED, MEDLINE and EMBASE, were performed with articles restricted to English language and human subjects. References were also identified from the bibliographies of selected articles.

RESULTS

Methods for measuring gastric acid include both invasive and non-invasive techniques. Invasive tests include the conventional gastric acid aspiration tests, gastric pH measurement techniques and endoscopic methods. Non-invasive methods use urinary analysis, breath analysis, serum pepsinogens assay, scintigraphic techniques, impedence tomography and alkaline tide for measurement of gastric acid.

CONCLUSIONS

Several methods of measuring gastric acid exist. Invasive tube tests are uncomfortable and time consuming, whereas most of the non-invasive methods are at best semiquantitative and useful in detecting low or absent acid secretion. Further attempts to explore new methods for measuring gastric acid are therefore warranted.

Deficient aldehyde dehydrogenase 2 is associated with increased risk for esophageal squamous cell carcinoma in the presence of gastric hypochlorhydria

OBJECTIVE

In Orientals, deficient aldehyde dehydrogenase 2 (ALDH2) is associated with an increased risk for esophageal squamous cell carcinoma (ESCC). The local metabolism of carcinogenic acetaldehyde in the upper gastrointestinal tract could be involved in the association, but the underlying mechanism has not been fully elucidated. Since an anacidic stomach can promote bacteria-catalyzed local acetaldehyde production, the gastric acid level could also affect acetaldehyde metabolism. This study investigated whether ALDH2-related susceptibility to ESCC differs depending on the gastric secretion level.

MATERIAL AND METHODS

Sixty-two patients with ESCC and sex- and age-matched normal controls were enrolled in this study. ALDH2 polymorphism was analyzed by polymerase chain-restriction fragment length polymorphism, and those with an inactive allele (ALDH2-1/2-2 or ALDH2-2/2-2) were defined as ALDH2 deficient. Gastrin-stimulated acid output was assessed by endoscopic gastrin test and hypochlorhydria was defined as 0.6 mEq/10 min or lower. Multiple logistic regression analyses were used to adjust for other potential confounders.

RESULTS

ALDH2 deficiency or hypochlorhydria was more prevalent in ESCC compared with controls and both showed increased independent associations with ESCC in multivariate analysis. Stratified analysis by the gastric acid secretion level revealed that the associations between the ALDH2 genotype and ESCC differed according to the individual gastric acid secretion levels and that ALDH2 deficiency was a significant risk factor for ESCC exclusively in individuals with hypochlorhydria with an odds ratio (95% confidence interval): 5.0 (1.2-21.2).

CONCLUSION

Microbial production of carcinogen acetaldehyde in the presence of gastric hypochlorhydria is most probably involved in the mechanism of ALDH2-related susceptibility to ESCC.

The role of serum pepsinogen in the detection of gastric cancer

The incidence of gastric cancer is very high in Japan, Korea, and China. Reducing the morbidity and mortality associated with gastric cancer requires early diagnosis, which can be facilitated by applying gastroscopy more frequently in high-risk groups. A strategy of population screening for gastric cancer is currently being adopted in Korea, Japan, and the Matsu region of Taiwan, but using different screening methods. In addition, the history of pepsinogen (PG) in research as a gastric cancer biomarker has varied, in that the use of serum levels of PGI and PGII and the PGI/PGII ratio as gastric cancer screening tools was introduced in Japan before 1990, but in Korea the first research results were only reported in 2008. This review first evaluates the physiology of PG, followed by the usefulness or limitations of serum PG testing with regard to the detection of gastric cancer. Finally, the factors affecting the efficacy of PG tests as a gastric cancer biomarker (i.e., Helicobacter pylori infection status, gender, histopathologic features, and cancer location and depth) are evaluated. It was found that the strategies used to increase the efficacy of PG tests should be individualized in each country according to the seroprevalence of H. pylori.

Alteration of correlation between serum pepsinogen concentrations and gastric acid secretion after H. pylori eradication

PURPOSE

The measurement of serum pepsinogens is clinically useful to represent gastric acid secretion. Since both serum pepsinogens and gastric acid secretion are considerably altered by H. pylori eradication, the correlation between these two parameters could be different prior to and after eradication. In this study, we investigated the correlation between the two parameters prior to and after eradication.

METHODS

One hundred eighteen H. pylori-positive patients with peptic ulcers or chronic gastritis were enrolled in this retrospective analysis. In all participants both the measurement of serum pepsinogens and the determination of gastric acid secretion were performed prior to and at 1 month after successful eradication. In 85 subjects, the same assessments were repeated at 7 months. Correlations between serum pepsinogens and gastric acid secretion were assessed using linear regression analysis.

RESULTS

The pepsinogen I/II ratio (r = 0.56) was a better indicator of gastric acid secretion in H. pylori-infected subjects than pepsinogen I itself (r = 0.31). Eradication of H. pylori altered the association, causing pepsinogen I (r = 0.55) to become a better indicator of gastric acid secretion compared with the pepsinogen I/II ratio (r = 0.40) at 1 month after eradication, followed by similar tendencies at 7 months.

CONCLUSION

Using different serum biomarkers (pepsinogen I/II ratio prior to eradication or pepsinogen I after eradication), the measurement of serum pepsinogens is useful for predicting the individual gastric acid secretion level not only in H. pylori-infected subjects, but also in subjects with histories of eradication of the infection.

Barrett's esophagus is characterized by the absence of Helicobacter pylori infection and high levels of serum pepsinogen I concentration in Japan

BACKGROUND AND AIM

It has been reported that patients with Barrett's esophagus (BE) may have gastric acid hypersecretion. Serological markers such as serum pepsinogen or gastrin have been used to estimate the gastric secretory function. The aim of this study was to compare the serum pepsinogen and gastrin concentrations in view of Helicobacter pylori infection status between BE patients and the controls.

METHODS

Thirty-six patients with long-segment BE were enrolled in this study. Three age- and sex-matched controls were assigned to each patient. Serum pepsinogen and gastrin concentrations were measured by radioimmunoassay and H. pylori infection was determined by histology and serum IgG antibodies.

RESULTS

Helicobacter pylori infection was present in 4 of 36 patients (11%) with BE and in 80 of 108 controls (74%), being less prevalent in BE patients than in the controls (P < 0.0001). When examined in the H. pylori-negative subjects, both the serum pepsinogen I and pepsinogen II concentrations in BE patients were significantly higher than those in the controls (mean pepsinogen I:BE 51.0 +/- 14.0 ng/mL vs control 38.9 +/- 13.5 ng/mL, P = 0.0012; mean pepsinogen II:BE 10.8 +/- 4.0 ng/mL vs control 7.9 +/- 2.0 ng/mL, P = 0.0097). There was no significant difference in the serum gastrin levels between BE patients and the controls irrespective of the H. pylori infection status.

CONCLUSIONS

Most of the Japanese BE patients are characterized by the absence of H. pylori infection and high levels of serum pepsinogen. Determination of the serum pepsinogen level in combination with the H. pylori infection status could be a useful serological marker for BE screening.

Extensive gastric atrophy: an increased risk factor for superficial esophageal squamous cell carcinoma in Japan

OBJECTIVES

A recent study in Sweden has reported that gastric atrophy is associated with an increased risk for esophageal squamous cell carcinoma. However, this finding needs to be confirmed in other ethnic groups due to the wide geographic variation of this cancer.

OBJECTIVES

To investigate whether gastric atrophy is associated with a risk for esophageal squamous cell carcinoma using a case-control study in Japanese subjects, a population known to have a high prevalence of H. pylori infection and accompanying gastric atrophy.

METHODS

Seventy-three patients who had undergone endoscopic mucosal resection for superficial esophageal squamous cell carcinoma, and 73 sex- and age-matched controls, were enrolled prospectively. Gastric fundic atrophy was evaluated by histology of biopsy specimens and serum pepsinogen I level (cutoff level 25 ng/mL). Conditional logistic regression model with adjustment for potential confounding factors was used to assess the associations.

RESULTS

Gastric atrophy, defined histologically or serologically, was independently associated with an increased risk for esophageal squamous cell carcinoma and the risk seemed to increase with the progression of the atrophy. Multivariate odds ratio (95% confidence interval) for histological fundic atropy, fundic intestinal metaplasia, and serological atrophy are 4.2 (1.5-11.7), 10.7 (2.3-50.4), and 8.2 (2.2-30.4), respectively.

CONCLUSIONS

Gastric atrophy, a newly recognized risk factor for esophageal squamous cell carcinoma in Sweden, is likely to be a risk factor in other areas. Further studies are warranted to explore the causal relationship.

Using serum pepsinogens wisely in a clinical practice

Serum pepsinogen (PG) has been used as biomarkers of gastric inflammation and mucosal status, including atrophic change, before the discovery of Helicobacter pylori (H. pylori). Serum pepsinogen I (PG I) and pepsinogen II (PG II) levels are known to increase in the presence of H. pylori-related nonatrophic chronic gastritis. The measurement of serum PG provides much information on the presence of intestinal metaplasia as well as atrophic gastritis. The eradication of H. pylori provokes a significant change in serum PG values: it reduces both PG I and PG II and elevates the PG I to PG II ratio. Recently, the serum PG test method has been the first screening step in Japan, as well as photofluorography. Serum PG tests are used to screen for high risk subjects with atrophic gastritis, rather than as a test for cancer itself. Unlike photofluorography or endoscopy, serum PG screening can identify non-ulcerated differentiated asymptomatic cancer, irrespective of the size and location of the lesion. Most cases detected by the PG method are asymptomatic early gastric cancers and are limited to the mucosa, which are particularly well suited for endoscopic treatment. The PG method can contribute greatly to the patients' quality of life.