Effect of Helicobacter pylori eradication therapy on clinical and laboratory biomarkers associated with gastric damage in healthy school-aged children: A randomized non-blinded trial

Spatial Study of TLR4, TLR5 and TLR9 in Gastric Premalignant Lesions Before and After Helicobacter pylori Eradication

The histological changes in the gastric epithelium are crucial in the progression from premalignant to neoplastic lesions. TLR4, TLR5 and TLR9 have been localized in the gastric epithelium and studied separately using conventional histological techniques without a focus on the protein or cell interactions within the microenvironment. Therefore, we developed a multiplex immunohistochemistry/immunofluorescence (mIHC/IF) technology for the simultaneous detection of TLR4, TLR5 and TLR9 on a single tissue section of human gastric biopsies from 10 paired cases collected in two independent visits, and its correlation with the OLGA/OLGIM scoring and H. pylori status after eradication. The results confirmed that mIHC/IF is useful for simultaneously interrogating six biomarkers and demonstrated that TLR4 and TLR9 are significantly associated with H. pylori infection. However, only TLR9 is positively related to the presence of intestinal metaplasia. TLR5 was mainly present in goblet cells (TFF3+) but did not show any significant association with H. pylori or the presence of intestinal metaplasia. Our results suggest that a more comprehensive strategy to interrogate the tissue microenvironment in premalignant lesions may improve the interpretation of the earned risk of gastric cancer in patients with chronic gastritis and evidence of failure in H. pylori eradication.

Protocol for a randomised 'screen-and-treat' Helicobacter pylori eradication trial in 14-18-years-old adolescents residing in three regions of Chile: effectiveness and microbiological host implications

INTRODUCTION

Gastric cancer is a major global health concern, being the final stage of a long-term process, primarily associated with Helicobacter pylori (H. pylori) infection. Early childhood acquisition of H. pylori with low spontaneous eradication rates underscores the need for preventive measures. Our previous pilot treatment study revealed high eradication rates, favourable tolerance profile and a decline in serum biomarkers indicative of gastric damage in asymptomatic school-aged children. The purpose of this study is to determine the potential benefit of a 'screen-and-treat' strategy targeting persistently infected, asymptomatic adolescents. Specific aims are to assess eradication efficacy, its clinical and molecular outcomes and potential clinical and microbiological side effects.

METHODS AND ANALYSIS

The screening phase will involve testing 500-1000 asymptomatic adolescents aged 14-18 from three cities in Chile using the urea breath test (UBT) to identify 210 participants with persistent infection. They will proceed to a randomised, non-blinded, controlled trial, receiving either a sequential eradication scheme for H. pylori or no treatment. Follow-up will span up to 24 months post-treatment, involving UBT, gastroenterological assessments and blood and stool sample collections. Concurrently, a subset of 60 uninfected adolescents will undergo matched follow-up. Enzyme-linked immunosorbent assay (ELISA) commercial kits will evaluate gastric damage biomarkers in serum (pepsinogen I and II, gastrin-17, VCAM-1, CXCL13). Stool samples will be employed for Escherichia coli and Enterococcus spp-culture, assessing AMR via the disk diffusion method. H. pylori clarithromycin resistance will be determined by molecular method from stool samples. The gut microbiome will be characterised by amplifying and sequencing the 16S rRNA gene from stool samples, followed by bioinformatics analysis.

ETHICS AND DISSEMINATION

Approved by the Human Research Ethics Committee at the Faculty of Medicine, University of Chile (073-2022). Findings will be disseminated in peer-reviewed journals and scientific meetings to guide future practices.

TRIAL REGISTRATION NUMBER

NCT05926804.

The Most Recent Insights into the Roots of Gastric Cancer

Helicobacter pylori (H. pylori) is the most common bacterial infection worldwide, usually being acquired during childhood, and its persistence into adulthood represents one of the main contributors of gastric carcinogenesis. Based on these statements, it would be of great importance to know if the most early premalignant transformation occurs in children or later since, this would enable the development of effective anti-tumorigenesis strategies. The interplay between H. pylori virulence factors, the host's responses modified by this infection, and the gastric microecology are complex and eventually lead to the development of gastric cancer in susceptible individuals. Several biomarkers were identified as major contributors of this long-lasting process, such as pepsinogens, gastrin 17, lipid-, glucose- and iron-metabolism parameters, immunity players, aberrant bacterial DNA methylation, H. pylori virulence factors, and hallmarks of gastric dysbiosis. Several of these biomarkers were also identified in children with H. pylori infection, independently of the presence of premalignant lesions, which were also proven to be present in a subgroup of H. pylori-infected children, especially those carrying extremely virulent strains. Therefore, the most incipient premalignant gastric changes might indeed occur early during childhood, opening a promising research gate for further studies to delineate the border between infection and cancer.

Is Helicobacter pylori Anyway Pathogen in Children?

Helicobacter pylori (H. pylori) infection is a continuous challenge for both gastroenterologists and pediatricians. The international guidelines regarding diagnostic and treatment pathways differ between adults and children. The pediatric guidelines are more restrictive because children are rarely affected by serious consequences, particularly in Western countries. Therefore, infected children should be treated only after a careful case-by-case evaluation by a pediatric gastroenterologist. In any case, recent studies are confirming an increasingly all-around pathological role of H. pylori even in asymptomatic children. For these reasons, following the current evidence, we feel that H. pylori-infected children could be treated starting in pre-adolescence, particularly in Eastern countries, because their stomachs have already begun to develop the biomarkers of gastric damage. Therefore, we believe that H. pylori is anyway pathogen in children. Nevertheless, the possible beneficial role of H. pylori in humans has not yet been conclusively disproved.