Quantification of serum levels of pepsinogens and gastrin to assess eradication of Helicobacter pylori

Utilization of an Automated Latex Agglutination Turbidity Assay for Assessing Gastric Mucosal Alteration during Helicobacter pylori Infection

Background/Aims

: A latex agglutination turbidity (LA) assay to test for serum antibodies has been approved in Japan and Korea for mass screening of Helicobacter pylori infection. In this study, we evaluated the LA assay for diagnosing H. pylori infection and predicting gastric mucosal changes in a Mongolian population.

Methods

: In total, 484 individuals were classified into H. pylori-positive (n=356) and H. pylori-negative (n=128) groups, as determined by histology and H. pylori culture.

Results

: The best cutoff, sensitivity, and specificity values for the LA assay were 18.35 U/mL, 74.2%, and 65.6%, respectively. The LA values in the atrophic gastritis group were statistically higher than those in the other groups (healthy, chronic gastritis, intestinal metaplasia, and gastric cancer, p<0.0001). The cutoff value to distinguish the atrophic gastritis group from the other four groups was 32.0 U/mL, and its area under the curve was 0.673, which was the highest among the E-plate, pepsinogen (PG) I, PG II, and PG I/II ratio tests in our data. The odds ratios for atrophic gastritis determined by the LA assay and PG I test in multiple logistic regression were 2.5 and 1.9, respectively, which were significantly higher than for the other tests.

Conclusions

: The LA assay can determine the risk of atrophic gastritis, which in turn is a considerable risk factor for gastric cancer. We propose using this assay in combination with the PG I/II ratio to avoid missing gastric cancer patients who have a low LA value (less than 32.0 U/mL).

Clinical value of serum pepsinogen in the diagnosis and treatment of gastric diseases

Pepsinogen, secreted from the gastric mucosa, is the precursor of pepsin. It is categorized as pepsinogen 1 and pepsinogen 2 based on its immunogenicity. The pepsinogen content that can enter the blood circulation through the capillaries of the gastric mucosa is approximately 1% and remains stable all the time. The pepsinogen content in serum will change with the pathological changes of gastric mucosa. Therefore, the level of pepsinogen in serum can play a role in serologic biopsy to reflect the function and morphology of different regions of gastric mucosa and serve as an indicator of gastric disease. This study conducts relevant research on serum pepsinogen 1, pepsinogen 2, and the ratio of pepsinogen 1 to pepsinogen 2, and reviews their important value in clinical diagnosis of Helicobacter pylori infection, gastric ulcer, and even gastric carcinoma, providing ideas for other researchers.

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.

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.).

Pepsinogen II in gastritis and Helicobacter pylori infection

BACKGROUND AND AIM

In the gastric mucosa, pepsinogen II (PgII) is produced/secreted by glands in the mucus-secreting antral and cardia compartments, but also by the chief cells and the oxyntic glands. Increasing PgII serum levels are associated with the whole spectrum of gastric inflammatory diseases, including gastritis induced by Helicobacter pylori (H. pylori). This review critically addresses the clinical value of PgII serology for assessing gastric mucosal inflammation, and as a marker of H. pylori status, in both H. pylori-positive patients and after eradication therapy.

RESULTS

A search in PubMed/Scopus records yielded 39 out of 1190 published scientific studies meeting the selection criteria for this study. In the studies considered, PgII levels were significantly associated with non-atrophic gastric inflammatory lesions (p-values: 0.025-0.0001). H. pylori-positive patients had significantly higher PgII levels than H. pylori-negative individuals (p-values: 0.o5-0.0001). While a significant drop in serum PgII levels is consistently reported in H. pylori-eradicated patients (p-values: from 0.05 to 0.0001), inconsistencies in the related negative and positive predictive values significantly lower the clinical reliability of PgII testing by comparison with other available non-invasive tests.

CONCLUSIONS

PgII serology may provide clinically useful information on gastric inflammatory diseases, particularly if they are non-atrophic. PgII serology is inconsistent, however, for the purposes of distinguishing patients whose H. pylori eradication therapy is successful from those who remain infected.

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.

Helicobacter pylori eradication: Exploring its impacts on the gastric mucosa

Helicobacter pylori (H. pylori) infects approximately 50% of all humans globally. Persistent H. pylori infection causes multiple gastric and extragastric diseases, indicating the importance of early diagnosis and timely treatment. H. pylori eradication produces dramatic changes in the gastric mucosa, resulting in restored function. Consequently, to better understand the importance of H. pylori eradication and clarify the subsequent recovery of gastric mucosal functions after eradication, we summarize histological, endoscopic, and gastric microbiota changes to assess the therapeutic effects on the gastric mucosa.

Non-invasive diagnostic tests for Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H pylori) infection has been implicated in a number of malignancies and non-malignant conditions including peptic ulcers, non-ulcer dyspepsia, recurrent peptic ulcer bleeding, unexplained iron deficiency anaemia, idiopathic thrombocytopaenia purpura, and colorectal adenomas. The confirmatory diagnosis of H pylori is by endoscopic biopsy, followed by histopathological examination using haemotoxylin and eosin (H & E) stain or special stains such as Giemsa stain and Warthin-Starry stain. Special stains are more accurate than H & E stain. There is significant uncertainty about the diagnostic accuracy of non-invasive tests for diagnosis of H pylori.

OBJECTIVES

To compare the diagnostic accuracy of urea breath test, serology, and stool antigen test, used alone or in combination, for diagnosis of H pylori infection in symptomatic and asymptomatic people, so that eradication therapy for H pylori can be started.

SEARCH METHODS

We searched MEDLINE, Embase, the Science Citation Index and the National Institute for Health Research Health Technology Assessment Database on 4 March 2016. We screened references in the included studies to identify additional studies. We also conducted citation searches of relevant studies, most recently on 4 December 2016. We did not restrict studies by language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We included diagnostic accuracy studies that evaluated at least one of the index tests (urea breath test using isotopes such as 13C or 14C, serology and stool antigen test) against the reference standard (histopathological examination using H & E stain, special stains or immunohistochemical stain) in people suspected of having H pylori infection.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the references to identify relevant studies and independently extracted data. We assessed the methodological quality of studies using the QUADAS-2 tool. We performed meta-analysis by using the hierarchical summary receiver operating characteristic (HSROC) model to estimate and compare SROC curves. Where appropriate, we used bivariate or univariate logistic regression models to estimate summary sensitivities and specificities.

MAIN RESULTS

We included 101 studies involving 11,003 participants, of which 5839 participants (53.1%) had H pylori infection. The prevalence of H pylori infection in the studies ranged from 15.2% to 94.7%, with a median prevalence of 53.7% (interquartile range 42.0% to 66.5%). Most of the studies (57%) included participants with dyspepsia and 53 studies excluded participants who recently had proton pump inhibitors or antibiotics.There was at least an unclear risk of bias or unclear applicability concern for each study.Of the 101 studies, 15 compared the accuracy of two index tests and two studies compared the accuracy of three index tests. Thirty-four studies (4242 participants) evaluated serology; 29 studies (2988 participants) evaluated stool antigen test; 34 studies (3139 participants) evaluated urea breath test-13C; 21 studies (1810 participants) evaluated urea breath test-14C; and two studies (127 participants) evaluated urea breath test but did not report the isotope used. The thresholds used to define test positivity and the staining techniques used for histopathological examination (reference standard) varied between studies. Due to sparse data for each threshold reported, it was not possible to identify the best threshold for each test.Using data from 99 studies in an indirect test comparison, there was statistical evidence of a difference in diagnostic accuracy between urea breath test-13C, urea breath test-14C, serology and stool antigen test (P = 0.024). The diagnostic odds ratios for urea breath test-13C, urea breath test-14C, serology, and stool antigen test were 153 (95% confidence interval (CI) 73.7 to 316), 105 (95% CI 74.0 to 150), 47.4 (95% CI 25.5 to 88.1) and 45.1 (95% CI 24.2 to 84.1). The sensitivity (95% CI) estimated at a fixed specificity of 0.90 (median from studies across the four tests), was 0.94 (95% CI 0.89 to 0.97) for urea breath test-13C, 0.92 (95% CI 0.89 to 0.94) for urea breath test-14C, 0.84 (95% CI 0.74 to 0.91) for serology, and 0.83 (95% CI 0.73 to 0.90) for stool antigen test. This implies that on average, given a specificity of 0.90 and prevalence of 53.7% (median specificity and prevalence in the studies), out of 1000 people tested for H pylori infection, there will be 46 false positives (people without H pylori infection who will be diagnosed as having H pylori infection). In this hypothetical cohort, urea breath test-13C, urea breath test-14C, serology, and stool antigen test will give 30 (95% CI 15 to 58), 42 (95% CI 30 to 58), 86 (95% CI 50 to 140), and 89 (95% CI 52 to 146) false negatives respectively (people with H pylori infection for whom the diagnosis of H pylori will be missed).Direct comparisons were based on few head-to-head studies. The ratios of diagnostic odds ratios (DORs) were 0.68 (95% CI 0.12 to 3.70; P = 0.56) for urea breath test-13C versus serology (seven studies), and 0.88 (95% CI 0.14 to 5.56; P = 0.84) for urea breath test-13C versus stool antigen test (seven studies). The 95% CIs of these estimates overlap with those of the ratios of DORs from the indirect comparison. Data were limited or unavailable for meta-analysis of other direct comparisons.

AUTHORS' CONCLUSIONS

In people without a history of gastrectomy and those who have not recently had antibiotics or proton ,pump inhibitors, urea breath tests had high diagnostic accuracy while serology and stool antigen tests were less accurate for diagnosis of Helicobacter pylori infection.This is based on an indirect test comparison (with potential for bias due to confounding), as evidence from direct comparisons was limited or unavailable. The thresholds used for these tests were highly variable and we were unable to identify specific thresholds that might be useful in clinical practice.We need further comparative studies of high methodological quality to obtain more reliable evidence of relative accuracy between the tests. Such studies should be conducted prospectively in a representative spectrum of participants and clearly reported to ensure low risk of bias. Most importantly, studies should prespecify and clearly report thresholds used, and should avoid inappropriate exclusions.

Effect of gastric acid-suppressive therapy and biological variation of serum gastrin concentrations in dogs with chronic enteropathies

BACKGROUND

Serum gastrin concentration can help diagnose gastrinomas in dogs if >3-10× the upper reference limit (URL), but antisecretory therapy and other conditions can also cause hypergastrinemia. Effects of antisecretory therapy (famotidine or ranitidine, omeprazole) on serum gastrin concentration in dogs with chronic enteropathy (CE) and its biological variation (BV) are unknown. Aim of the study was to evaluate serum gastrin in acid-suppressant-treated or -naïve CE dogs; test the association between serum gastrin and histopathologic findings in acid-suppressant-naïve CE dogs; and evaluate the BV of serum gastrin in dogs not receiving any gastric acid suppressive therapy. Samples from 231 dogs were used and serum gastrin was measured by chemiluminescence assay. Gastric and duodenal histologic lesions were evaluated and graded. BV of serum gastrin was evaluated in serial samples.

RESULTS

Serum gastrin concentrations were significantly higher in acid-suppressant-treated than acid-suppressant-naïve dogs (P = 0.0245), with significantly higher concentrations in proton pump inhibitor (PPI)- than H2-antihistamine-treated patients (P = 0.0053). More PPI- than H2-antihistamine-treated dogs had gastrin concentrations above URL (P = 0.0205), but not >3× nor >10× the URL. Serum gastrin concentrations correlated with the severity of gastric antral epithelial injury (P = 0.0069) but not with any other lesions or the presence/numbers of spiral bacteria in gastric biopsies. Intra- and inter-individual BV were 43.4 and 21.6%, respectively, in acid-suppressant-naïve dogs, with a reciprocal individuality index of 0.49 and a critical difference of ≥29.5 ng/L.

CONCLUSIONS

Antisecretory (particularly PPI) treatment leads to hypergastrinemia in CE dogs, but the concentrations seen in this study are unlikely to compromise a diagnosis of gastrinoma. Use of a population-based URL for canine serum gastrin and a URL of ≤27.8 ng/L are appropriate.

A significant increase in the pepsinogen I/II ratio is a reliable biomarker for successful Helicobacter pylori eradication

Background

Helicobacter pylori (H. pylori) eradication is usually assessed using the ¹³C-urea breath test (UBT), anti-H. pylori antibody and the H. pylori stool antigen test. However, a few reports have used pepsinogen (PG), in particular, the percentage change in the PG I/II ratio. Here, we evaluated the usefulness of the percentage changes in serum PG I/II ratios for determining the success of eradication therapy for H. pylori.

Materials and methods

In total, 650 patients received eradication therapy from October 2008 to March 2013 in our Cancer Institute Hospital. We evaluated the relationship between H. pylori eradication and percentage changes in serum PG I/II ratios before and 3 months after treatment with CLEIA^® (FUJIREBIO Inc, Tokyo, Japan). The gold standard of H. pylori eradication was defined as negative by the UBT performed 3 months after completion of eradication treatment. Cut-off values for percentage changes in serum PG I/II ratios were set as +40, +25 and +10% when the serum PG I/II ratio before treatment was below 3.0, above 3.0 but below 5.0 and 5.0 or above, respectively.

Results

Serum PG I and PG II levels were measured in 562 patients with H. pylori infection before and after eradication therapy. Eradication of H. pylori was achieved in 433 patients studied (77.0%). The ratios of first, second, third-line and penicillin allergy eradication treatment were 73.8% (317/429), 88.3% (99/112), 75% (12/16) and 100% (5/5), respectively. An increasing percentage in the serum levels of the PG I/II ratios after treatment compared with the values before treatment clearly distinguished success from failure of eradication (108.2±57.2 vs. 6.8±30.7, p<0.05). Using the above cut-off values, the sensitivity, specificity and validity for determination of H. pylori were 93.1, 93.8 and 93.2%, respectively.

Conclusion

In conclusion, the percentage changes in serum PG I/II ratios are useful as evaluation criteria for assessing the success of eradication therapy for H. pylori.

Management of Helicobacter pylori Infection: What Should the Surgeon Know?

Infection with Helicobacter pylori continues to represent a major global health care burden, and various national and international consensus reports and guidelines have aimed at tracking recent developments for their translation into an optimized clinical management. The most important 'innovation' is the definition of H. pylori gastritis as an infectious disease. This does imply the consideration of therapy of this condition even before the development of clinical manifestations including non-malignant and malignant gastroduodenal diseases, such as peptic ulcer disease, gastric cancer, and gastric mucosa-associated lymphoid tissue lymphoma. Treatment of H. pylori is facing an increasing number of failures, with the main reason being an increasing antibiotic resistance to some of the previously most effective antibiotics, i.e. clarithromycin and levofloxacin, for H. pylori strains. Several new treatment options or modifications of already established regimens have been introduced to overcome bacterial resistance and treatment failure. In this review, we provide an update on the current recommendations for a successful management of H. pylori infection, and in this context a special reference is made to the role of visceral surgeons.

Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report

Important progress has been made in the management of Helicobacter pylori infection and in this fifth edition of the Maastricht Consensus Report, key aspects related to the clinical role of H. pylori were re-evaluated in 2015. In the Maastricht V/Florence Consensus Conference, 43 experts from 24 countries examined new data related to H. pylori in five subdivided workshops: (1) Indications/Associations, (2) Diagnosis, (3) Treatment, (4) Prevention/Public Health, (5) H. pylori and the Gastric Microbiota. The results of the individual workshops were presented to a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in the various clinical scenarios.

Long-term dynamics of gastric biomarkers after eradication of Helicobacter pylori infection

BACKGROUND

Secretion of pepsinogen I (PgI), pepsinogen II (PgII), fasting gastrin-17 (fG-17) and stimulated gastrin-17 (sG-17) changes after Helicobacter pylori eradication. Few data are available on the long-term dynamics of gastric biomarkers after H. pylori eradication.The aim of this study was to investigate the dynamics of gastric biomarkers in H. pylori-positive patients after eradication over a 3-year period and to compare the levels with initially H. pylori-negative patients.

MATERIALS AND METHODS

Blood samples for the detection of gastric biomarkers were obtained from dyspeptic patients coming for upper gastrointestinal endoscopy. In H. pylori-positive patients, after eradication therapy, three follow-up blood samples were drawn after 12, 24 and 36 months; in H. pylori-negative patients, two samples were taken - at 12 and after 30 months. Median values of biomarkers in follow-up samples were compared with the baseline sample.

RESULTS

The final sample included 110 patients (median age 67 years, M/F ratio 27/83). In patients after H. pylori eradication (n=83) PgI, PgII, fG-17 and sG-17 had decreased significantly during a 36-month period, whereas the PgI/PgII ratio had increased significantly from 5.59 to 11.64.

CONCLUSION

In H. pylori-positive dyspeptic patients, after eradication therapy, a decrease in PgI, PgII, fG-17 and sG-17 was observed after 36 months whereas an increase in the PgI/II ratio suggested an improvement in gastric atrophy. The median levels of gastric biomarkers in patients after H. pylori eradication therapy may become similar to biomarker levels among initially H. pylori-negative individuals.

Pepsinogen testing for evaluation of the success of Helicobacter pylori eradication at 4 weeks after completion of therapy

BACKGROUND AND OBJECTIVE

Pepsinogen levels in plasma are increased by inflammation in the gastric mucosa, including inflammation resulting from Helicobacter pylori infection. A decrease in pepsinogen II level has been suggested as a reliable marker to confirm the successful eradication of infection. The aim of our study was to evaluate the potential role of pepsinogens I and II, gastrin-17 and H. pylori antibodies in confirming successful eradication.

MATERIAL AND METHODS

Altogether 42 patients (25 women, 17 men), mean age 45 years (range 23-74), were enrolled. Pepsinogens I and II, gastrin-17 and H. pylori IgG antibodies were measured in plasma samples using an ELISA test (Biohit, Oyj., Finland) before the eradication and 4 weeks after completing the treatment. The success of eradication was determined by a urea breath test.

RESULTS

Eradication was successful in 31 patients (74%) and unsuccessful in 11 patients (26%). Pepsinogen II decreased significantly in both the successful (P=0.029) and unsuccessful (P=0.042) eradication groups. Pepsinogen I decreased significantly in the successful (P=0.025) but not the unsuccessful (P=0.29) eradication group. The pepsinogen I/II ratio increased in the successful eradication group (P=0.0018) but not in the group in which treatment failed (P=0.12). There were no differences in gastrin-17 or H. pylori antibody values.

CONCLUSIONS

A decrease in pepsinogen II levels cannot be used as a reliable marker for the successful eradication of H. pylori 4 weeks after the completion of treatment. The increase in pepsinogen I/II ratio reflects differences in pepsinogen production following the eradication irrespective of improvement in atrophy.

Helicobacter pylori protein-specific antibodies and risk of colorectal cancer

BACKGROUND

There is biologic plausibility as to why infection with Helicobacter pylori, the leading cause of gastric cancer, may also increase the risk of colorectal cancer, but the epidemiologic findings have been inconsistent. We assessed the association of H. pylori protein-specific infection and colorectal cancer risk in the prospective cohort, the Southern Community Cohort Study.

METHODS

Multiplex serology was used to measure antibodies to 15 H. pylori proteins in prediagnostic blood among 188 incident colorectal cancer cases and 370 controls matched by age, race, sex, and blood collection timing. Conditional logistic regression was used to calculate ORs and 95% confidence intervals (CI).

RESULTS

Overall H. pylori prevalence was not associated with colorectal cancer risk (OR, 1.03; 95% CI, 0.59-1.77). However, seropositivity to any of five specific H. pylori proteins (VacA, HP231, HP305, NapA, and HcpC) was associated with a significant 60% to 80% increase in odds of risk. These associations became even stronger when limited to colon cancer risk, particularly for the known H. pylori toxin VacA (OR, 2.24; 95% CI, 1.22-4.11), including a significant, positive dose-response association by VacA antibody levels in quartiles (P < 0.05). Associations with VacA seropositivity were especially strong for early-onset and late-stage cancers.

CONCLUSIONS

The findings raise the hypothesis that individuals with high levels of antibodies to specific H. pylori proteins may be at higher risk of colon cancer.

IMPACT

Further investigation of the H. pylori-colorectal cancer association is warranted to determine the possibility of protein-specific antibody levels as a risk biomarker.

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.

Accuracy and cut-off values of pepsinogens I, II and gastrin 17 for diagnosis of gastric fundic atrophy: influence of gastritis

Background

To establish optimal cutoff values for serologic diagnosis of fundic atrophy in a high-risk area for oesophageal squamous cell carcinoma and gastric cancer with high prevalence of Helicobacter pylori (H. pylori) in Northern Iran, we performed an endoscopy-room-based validation study.

Methods

We measured serum pepsinogens I (PGI) and II (PGII), gastrin 17 (G-17), and antibodies against whole H. pylori, or cytotoxin-associated gene A (CagA) antigen among 309 consecutive patients in two major endoscopy clinics in northeastern Iran. Updated Sydney System was used as histology gold standard. Areas under curves (AUCs), optimal cutoff and predictive values were calculated for serum biomarkers against the histology.

Results

309 persons were recruited (mean age: 63.5 years old, 59.5% female). 84.5% were H. pylori positive and 77.5% were CagA positive. 21 fundic atrophy and 101 nonatrophic pangastritis were diagnosed. The best cutoff values in fundic atrophy assessment were calculated at PGI<56 µg/l (sensitivity: 61.9%, specificity: 94.8%) and PGI/PGII ratio<5 (sensitivity: 75.0%, specificity: 91.0%). A serum G-17<2.6 pmol/l or G-17>40 pmol/l was 81% sensitive and 73.3% specific for diagnosing fundic atrophy. At cutoff concentration of 11.8 µg/l, PGII showed 84.2% sensitivity and 45.4% specificity to distinguish nonatrophic pangastritis. Exclusion of nonatrophic pangastritis enhanced diagnostic ability of PGI/PGII ratio (from AUC = 0.66 to 0.90) but did not affect AUC of PGI. After restricting study samples to those with PGII<11.8, the sensitivity of using PGI<56 to define fundic atrophy increased to 83.3% (95%CI 51.6–97.9) and its specificity decreased to 88.8% (95%CI 80.8–94.3).

Conclusions

Among endoscopy clinic patients, PGII is a sensitive marker for extension of nonatrophic gastritis toward the corpus. PGI is a stable biomarker in assessment of fundic atrophy and has similar accuracy to PGI/PGII ratio among populations with prevalent nonatrophic pangastritis.