Helicobacter pylori Infection, Gastric Cancer and Gastropanel

Assessing gastric cancer risk using the OLGA and OLGIM systems in Republic of Moldova

Background

Gastric cancer is still an important public health problem. Efforts have been made to lower its prevalence globally. The Operative Link on Gastritis Assessment (OLGA) and operating link for gastric intestinal metaplasia (OLGIM) histological grading systems have been proposed to identify individuals with types of gastritis that have the potential to become malignant.

Aim of the study

Our study was conducted to assess the value of OLGA and OLGIM systems in the diagnosis of gastric precancerous lesions, in the Moldovan population.

Methods

In a prospective study, 142 consecutive patients with chronic atrophic gastritis (CAG) from a larger group of patients referred to upper gastrointestinal endoscopy for dyspeptic symptoms or gastric cancer screening was investigated. The sample was divided into three groups: (a) CAG without intestinal metaplasia and gastric dysplasia; (b) CAG with intestinal metaplasia; (c) CAG with gastric dysplasia according to the morphological type of the lesion. GastroPanel biomarkers were correlated with OLGA and OLGIM stages.

Results

There was a direct, moderate and statistically significant correlation between types of CAG and OLGA stages (p < 0.001), a direct, weak and statistically significant correlation between forms of chronic atrophic gastritis and OLGIM stages (p < 0.001). A statistically significant reduction in Pepsinogen I and the Pepsinogen-I/Pepsinogen-II ratio was observed alongside an increase in the stages of the OLGA and OLGIM systems.

Conclusion

OLGA and OLGIM systems are useful tools in diagnosing CAG. This is the first study assessing the use of this systems in the Moldovan population.

Value of serum pepsinogen ratio screening for early gastric cancer and precancerous lesions in Youcheng area

BACKGROUND

The 5-year survival rate of patients with advanced gastric cancer remains extremely low (< 15%), whereas the 5-year survival rate of patients with early gastric cancer (EGC) is > 90%. Consequently, strengthening the screening of patients with EGC and precancerous lesions (PCLs) is essential.

AIM

To identify the value of serum pepsinogen ratio (PGR) screening for EGC and PCLs in the Shengli Oilfield Central Hospital.

METHODS

We first selected 385 patients with gastric lesions in the Youcheng area, determining benign lesions, PCLs, and EGC in 135, 123, and 127 cases, respectively, based on endoscopy and case diagnosis. The positive rates of pepsinogen I, pepsinogen II and Helicobacter pylori (H. pylori) in the three groups were detected, and the PGR was calculated. Subsequently, we plotted receiver operating characteristic curves to analyze the screening value of PGR and H. pylori-positive rates for PCLs and EGC.

RESULTS

PGR expression demonstrated a decreasing trend in patients with benign lesions, PCLs, and EGC successively according to the detection results, whereas the H. pylori-positive rate was notably increased in patients with PCLs and EGC compared to those with benign lesions. The area under the curves (AUCs) of PGR, H. pylori, and their combination in differentiating patients with benign lesions from those with PCLs were 0.611, 0.582, and 0.689, respectively; PGR, H. pylori, and their combination had an AUC of 0.618, 0.502, and 0.618 in distinguishing PCL patients from EGC patients, respectively; the AUCs of PGR, H. pylori, and their combination in discriminating patients with benign lesions from those with EGC were 0.708, 0.581, and 0.750, respectively.

CONCLUSION

PGR has great screening potential for patients with EGC and PCLs in the Youcheng area, and the screening efficiency is further improved by combining the H. pylori-positive rate.

Detection Rate of Helicobacter Pylori Infection and Atrophic Gastritis Using Serological Markers “GastroPanel®” Among Employees of the National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation

Aim: to evaluate, using the “GastroPanel®”, the frequency of detection of H. pylori infection and associated gastric diseases among doctors and medical staff of the National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation, Moscow.

Materials and methods. Employees of three branches of the National Medical Research Radiological Centre (n = 434, mean age — 48.5 ± 0.6 years) were examined using laboratory tests “GastroPanel®” (Biohit Oyj, Finland). The test results make it possible to identify infection of the stomach with H. pylori, hypo- and hyperacid conditions, as well as atrophic gastritis of the antrum and body of the stomach, as its precancerous conditions. Esophagogastroduodenoscopy (EGDS) for suspected atrophic gastritis was performed with an Olympus GIF-HQ190 video endoscope (Japan) in a narrow-spectrum mode with close focus (NBI Dual Focus).

Results. The absence of pathological signs detected by “GastroPanel®” was established in 23.3 % of cases, hyperacid state — in 18.4 %, and hypoacid state — in 5.2 %. These disorders are classified as functional. Consequently, the conditional norm in total was identified in 46.9 % of observations. An increased level of antibodies to H. pylori was found in 43.3 % of those examined. Atrophic gastritis in the body of the stomach according to the results of the “GastroPanel®” was detected in 4.8 % of cases (median age — 59 years), in the antrum (or increased secretion of hydrochloric acid) — also in 4.8 % of cases (median age — 52 years). Within two months after laboratory diagnostics, EGDS was performed for 10 out of 15 patients examined at the P. Hertsen Moscow Oncology Research Institute in whom, based on the results of the “GastroPanel®”, the presence of atrophic gastritis in the antrum (or increased secretion of hydrochloric acid) was suspected. In 6 out of 10 cases, atrophic gastritis of the antrum was confirmed (in two of them, the atrophy extended to the body of the stomach and was assessed as severe). Of the 11 people with the “GastroPanel®” conclusion “Atrophic gastritis of the body of the stomach,” an endoscopic examination was carried out in 7 persons, and in all these cases the diagnosis was confirmed, and in two people the conclusion was made of severe atrophic pangastritis.

Conclusion. “GastroPanel®” confirmed its high significance in identifying H. pylori infection and precancerous atrophic changes in the gastric mucosa. Regarding the occupational risks of infection among medical workers, we consider it advisable to conduct such screening without selecting an asymptomatic population.

Generation and characterization of nanobodies targeting human pepsinogens

Human pepsinogens (mainly pepsinogen I and pepsinogen II) are the major inactive precursor forms of the digestive enzyme pepsin which play a crucial role in protein digestion. The levels and ratios of human pepsinogens have demonstrated potential as diagnostic biomarkers for gastrointestinal diseases, particularly gastric cancer. Nanobodies are promising tools for the treatment and diagnosis of diseases, owing to their unique recognition properties. In this study, recombinant human pepsinogens proteins were expressed and purified as immunized antigens. We constructed a VHH phage library and identified several nanobodies via phage display bio-panning. We determined the binding potency and cross-reactivity of these nanobodies. Our study provides technical support for developing immunodiagnostic reagents targeting human pepsinogens.

KRT18 Modulates Alternative Splicing of Genes Involved in Proliferation and Apoptosis Processes in Both Gastric Cancer Cells and Clinical Samples

Keratin 18 (KRT18), one of the most abundant keratins in epithelial and endothelial cells, has been reported to be aberrantly expressed in many malignancies and extensively regarded as a biomarker and important regulator in multiple cancers, including gastric cancer (GC). But the molecular regulatory mechanisms of KRT18 in GC patients and cells are largely unknown. In the present study, we analyzed the expression level of KRT18 in 450 stomach adenocarcinoma tissue samples from TCGA database and found a significantly higher expression level in tumor tissues. We then explored the potential functions of KRT18 in AGS cells (human gastric adenocarcinoma cell line) by KRT18 knockdown using siRNA and whole transcriptome RNA-seq analysis. Notably, KRT18 selectively regulates expression of cell proliferation and apoptotic genes. Beyond this, KRT18 affects the alternative splicing of genes enriched in apoptosis, cell cycle, and other cancer-related pathways, which were then validated by reverse transcription-quantitative polymerase chain reaction approach. We validated KRT18-KD promoted apoptosis and inhibited proliferation in AGS cells. We then used RNA-seq data of GC samples to further demonstrate the modulation of KRT18 on alternative splicing regulation. These results together support the conclusion that KRT18 extensively modulates diverse alternative splicing events of genes enriched in proliferation and apoptosis processes. And the dysregulated splicing factors at transcriptional or posttranscriptional level by KRT18 may contribute to the alternative splicing change of many genes, which expands the functional importance of keratins in apoptotic and cell cycle pathways at the posttranscriptional level in GC.

Chronic atrophic gastritis: an update on diagnosis

Background and aim

Atrophic gastritis is a precancerous gastric lesion, therefore its early detection is a priority in preventing gastric cancer. The aim of the present paper is to develop a narrative synthesis of the present knowledge on diagnostic methods of chronic atrophic gastritis.

Methods

A literature search was carried out on main databases: PubMed, Hinari, SpringerLink and Scopus (Elsevier) for the period 2000–2020. The searched keywords were: chronic atrophic gastritis, intestinal metaplasia and dysplasia + diagnosis. Inclusion criteria were focused on the articles about the invasive and non-invasive diagnosis of chronic atrophic gastritis and of precancerous gastric lesions, intestinal metaplasia and dysplasia; exclusion criteria were articles published before 2000 and those that did not include the proposed theme.

Results

The search returned 575 papers addressing the topic of precancerous lesions. From these, 60 articles were qualified representative for the materials published on the topic of this synthesis article, being those that met the inclusion criteria. The data emphasize the need to use upper digestive endoscopy with biopsies for the diagnosis of chronic atrophic gastritis. However serological diagnosis is available as alternative mainly recommended in follow up.

Conclusions

There are two main methodological approaches for the evaluation of chronic atrophic gastritis as a precancerous gastric lesions: invasive examination, which requires histological analysis of biopsy samples taken during upper digestive endoscopy, being the “gold standard” for diagnosis, and non-invasive serological examination using markers of gastric function.

Polymorphisms in Pepsinogen C and miRNA Genes Associate with High Serum Pepsinogen II in Gastric Cancer Patients

Background: Pepsinogen (PG) II (PGII) is a serological marker used to estimate the risk of gastric cancer but how PGII expression is regulated is largely unknown. It has been suggested that PGII expression, from the PGC (Progastricsin) gene, is regulated by microRNAs (miRNA), but how PGII levels vary with Helicobacter pylori (H. pylori) infection and miRNAs genotype remains unclear. Methods: Serum levels of PGI and PGII were determined in 80 patients with gastric cancer and persons at risk for gastric cancer (74 first-degree relatives of patients, 62 patients with autoimmune chronic atrophic gastritis, and 2 patients with dysplasia), with and without H. pylori infection. As control from the general population, 52 blood donors were added to the analyses. Associations between PGII levels and genetic variants in PGC and miRNA genes in these groups were explored based on H. pylori seropositivity and the risk for gastric cancer. The two-dimensional difference in gel electrophoresis (2D-DIGE) and the NanoString analysis of messenger RNA (mRNAs) from gastric cancer tissue were used to determine the pathways associated with increased PGII levels. Results: PGII levels were significantly higher in patients with gastric cancer, and in those with H. pylori infection, than in other patients or controls. A PGI/PGII ratio ≤ 3 was found better than PGI < 25 ng/mL to identify patients with gastric cancer (15.0% vs. 8.8%). For two genetic variants, namely rs8111742 in miR-Let-7e and rs121224 in miR-365b, there were significant differences in PGII levels between genotype groups among patients with gastric cancer (p = 0.02 and p = 0.01, respectively), but not among other study subjects. Moreover, a strict relation between rs9471643 C-allele with H. pylori infection and gastric cancer was underlined. Fold change in gene expression of mRNA isolated from gastric cancer tissue correlated well with polymorphism, H. pylori infection, increased PGII level, and pathway for bacteria cell entry into the host. Conclusions: Serum PGII levels depend in part on an interaction between H. pylori and host miRNA genotypes, which may interfere with the cut-off of PGI/PGII ratio used to identify persons at risk of gastric cancer. Results reported new findings regarding the relation among H. pylori, PGII-related host polymorphism, and genes involved in this interaction in the gastric cancer setting.

HIV related hypochlorhydria does not appear to respond to anti-retroviral therapy in Zambian adults: a case control study

INTRODUCTION

Human Immunodeficiency Virus (HIV) infection is associated with hypochlorhydria but the mechanism is unknown. The objective of this study was to determine effects of anti-retroviral therapy (ART) on gastric physiology as measured by validated markers.

METHODS

We studied HIV infected individuals who were either ART-naïve or on treatment with undetectable viral loads. We measured H.pylori IgG antibodies, pepsinogen (PG) 1 and 2 levels and fasting gastrin-17 using Biohit GastroPanel®. Gastric antral biopsies and juice were obtained for histology and pH respectively. Also included were historical data from HIV negative participants (n = 72) in a previous study, for reference.

RESULTS

We enrolled 84 HIV positive individuals with a median age 42 years (IQR 37-40 years). 55(66%) were female, 32(38%) were ART naïve, and 52(62%) were on ART. Hypochlorhydria (pH>4) was present in 48(57%) of the HIV positive and 18(25%) of the HIV negative individuals (OR 4: 95% CI 1.9-8.5, P<0.001) with no significant effect of ART (OR 0.9: 95% CI 0.3-2.3, P = 0.82). Hypochlorhydria was not associated with the serological detection of corpus atrophy using low PG 1:2 ratio (OR 2.1: 95% CI 0.5-10.2, P = 0.37) or GastroPanel® algorithm, (OR 0.7: 95% CI 0.01-60.1, P = 1.0). ART reduced the frequency of low PG 1:2 ratio (P = 0.001), but not the histological detection in the antrum of atrophy or non-atrophic gastritis.

CONCLUSION

ART use is associated with reduced serological evidence of corpus atrophy but has no effect on fasting pH, supporting earlier data that suggest that the mechanism of HIV-associated hypochlorhydria is multifactorial.

Gastric Cancer Screening by Combined Determination of Serum Helicobacter pylori Antibody and Pepsinogen Concentrations: ABC Method for Gastric Cancer Screening

Objective:

Gastroscopy combined with gastric mucosa biopsies is currently regarded as a gold standard for diagnosis of gastric cancer. However, its application is restricted in clinical practice due to its invasive property. A new noninvasive population screening process combining the assay of anti-Helicobacter pylori antibody and serum pepsinogen (PG) (ABC method) is adopted to recognize the high-risk patients for further endoscopy examination, avoiding the unnecessary gastroscopy for most population and saving the cost consumption for mass screening annually. Nevertheless, controversies exist for the grouping of ABC method and the intervals of gastroscopy surveillance for each group. In this review, we summarized these popular concerned topics for providing useful references to the healthcare practitioner in clinical practice.

Data Sources:

The PubMed databases were systematically searched from the inception dates to November 22, 2017, using the keywords “Helicobacter pylori,” “Pepsinogens,” and “Stomach Neoplasms.”

Study Selection:

Original articles and reviews on the topics were selected.

Results:

Anti-H. pylori antibody and serum PG concentration showed significant changes under the different status of H. pylori infection and the progression of atrophic gastritis, which can be used for risk stratification of gastric cancer in clinic. In addition, anti-H. pylori antibody titer can be used for further risk stratification of gastric cancer contributing to determine better endoscopy surveillance interval.

Conclusions:

The early detection and diagnosis of gastric cancer benefit from the risk stratification, but the cutoff values for H. pylori antibody and serum PG concentration require further modification.

Pathogenic roles of alterations in vitamin D and vitamin D receptor in gastric tumorigenesis

Gastric cancer is currently the second leading cause of cancer-related death worldwide, especially in Japan, Korea and China, and the 5-year survival rate of gastric cancer is less than 30%. Thus, it is important to shed more lights on novel agents to prevent gastric cancer or to improve survival rate of the patients. Vitamin D not only maintains calcium and bone homeostasis, but also mostly inhibits tumor genesis, invasion, and metastasis through activation of vitamin D receptor. Although epidemiological results are not consistent, accumulating evidence from gastric cancer cells, animal models, and clinical trials suggest that vitamin D deficiency may increase the risk and mortality of gastric cancer, but vitamin D supplement might be a safe and economical way to prevent or treat gastric cancer. Here, we reviewed the current studies on vitamin D and its receptor and focused on the pathogenic roles of their alterations in gastric tumorigenesis.

Regulatory effect of traditional Chinese medicine on brain-gut peptides in chronic atrophic gastritis

Chronic atrophic gastritis (CAG) is a common digestive system disease, which belongs to a type of precancerous lesion of gastric cancer (PLGC). Modern medical research has shown that brain-gut peptides, such as ghrelin, gastrin, somatostatin, and motilin, play an important role in the pathogenesis of CAG and PLGC. In particular, brain-gut peptides can help to judge the traditional Chinese medicine (TCM) syndrome of CAG and thereby evaluate CAG progression and the therapeutic effect. Based on TCM theory and brain gut interaction, this paper discusses the regulatory effect of TCM intervention on brain-gut peptides in CAG, with an aim to provide a theoretical basis for TCM prevention and treatment of CAG.