The interplay between Helicobacter pylori and the gut microbiota: An emerging driver influencing the immune system homeostasis and gastric carcinogenesis.

The human gut microbiota are critical for preserving the health status because they are required for digestion and nutrient acquisition, the development of the immune system, and energy metabolism. The gut microbial composition is greatly influenced by the colonization of the recalcitrant pathogen Helicobacter pylori (H. pylori) and the conventional antibiotic regimens that follow. H. pylori is considered to be the main microorganism in gastric carcinogenesis, and it appears to be required for the early stages of the process. However, a non-H. pylori microbiota profile is also suggested, primarily in the later stages of tumorigenesis. On the other hand, specific groups of gut microbes may produce beneficial byproducts such as short-chain fatty acids (acetate, butyrate, and propionate) that can modulate inflammation and tumorigenesis pathways. In this review, we aim to present how H. pylori influences the population of the gut microbiota to modify the host immunity and trigger the development of gastric carcinogenesis. We will also highlight the effect of the gut microbiota on immunotherapeutic approaches such as immune checkpoint blockade in cancer treatment to present a perspective for further development of innovative therapeutic paradigms to prevent the progression of H. pylori-induced stomach cancer.

Expression analysis of miRNA-155 level in Helicobacter pylori related inflammation and chronic gastritis.

Background and Objectives: Helicobacter pylori, is a major etiologic agent associated with gastritis. There is more evidence of noncoding microRNAs (miRs) dysregulation in gastrointestinal diseases, including inflammation caused by Helicobacter pylori. Also, the classification of gastrointestinal malignancies using the miRs profile is better than the protein profile. MiRNA-155(miRNA-155) among other miRs plays an important role in control of inflammation and gastric malignancy, so it can be remarkable prognosis marker of gastric cancer in the phase of chronic gastritis. The aim of this study was to compare the expression of miRNA-155 in gastric biopsy and serum samples of adult patients with chronic gastritis. Materials and Methods: Biopsy and blood samples were collected from endoscopy candidates at Taleghani hospital, Tehran, during 2019. H. pylori infection was detected using histology, culture and molecular PCR methods. Based on cagA and vacA genotyping, the toxicity of H. pylori isolates were determined. After RNA extraction, the expression rate of miRNA-155 was evaluated by real-time polymerase chain reaction (RT-PCR) in gastric tissue and serum of adults infected by H. pylori (n = 30) compared with control group without infection (n = 20). RNU6 housekeeping miRNA were used as endogenous control and statistical analyses were performed using SPSS, ANOVA and Student's t-test. Results: miRNA-155 expression in H. pylori infected adult patients increased significantly by 5.61 and 10.11 fold in serum and tissue respectively, compared to that observed in the control group. Evaluation of miRNA-155 expression pattern in relation to bacterial virulence factors showed that the increase in miRNA-155 expression is independent of CagA and VacA toxins. Conclusion: According to the differential expression patterns of miRNA-155 in serum samples of the infected adult patients, miRNA-155 has the potential to evaluate as chronic gastritis marker.

The Anti-Helicobacter pylori Effects of Lactobacillus acidophilus, L. plantarum, and L. rhamnosus in Stomach Tissue of C57BL/6 Mice.

BACKGROUND AND AIM: Helicobacter pylori is one of the most common pathogenic bacteria in the human gut, and is also one of the most important factors that cause digestive disorders such as chronic inflammation, gastric ulcers, and even gastric cancer. Since the use of various antibiotics to treat H. pylori infection is associated with the development of resistance in this bacterium, the aim of this study was to determine the anti-H. pylori effects of Lactobacillus acidophilus, L. plantarum, and L. rhamnosus in the stomach tissue of C57BL/6 mice. MATERIALS AND METHODS: In this experimental study, 70 mice in ten groups were evaluated from July to September 2017 in the microbiology laboratory of the School of Medicine, Alborz University of Medical Sciences, Karaj, Iran. After induction of H. pylori infection in mice with the standard strain of H. pylori (ATCC 43504), the infected mice were treated with drug and Lactobacillus species in different groups. Then, the anti-H. pylori effects of lactobacilli were evaluated by stool antigen test and tissue staining. RESULTS: Based on ELISA results and histological findings, a reduction of inflammation was observed. The group which was only exposed to L. rhamnosus and the one which was exposed to all three strains of Lactobacillus showed the highest antimicrobial effect on H. pylori. CONCLUSION: According to the results of this study, probiotic bacteria including L. acidophilus, L. plantarum, and L. rhamnosus could be useful in the reduction of H. pylori infection in the mouse model.

O mel-derivado de Lactobacillus rhamnosus alivia a infecção gastro-intestinal induzida pelo Helicobacter pylori-e inflamação gástrica em C57Bl/6 ratos: um estudo imuno-histológico / Honey-derived lactobacillus rhamnosus alleviates helicobacter pylori-induced gastro-intestinal infection and gastric inflammation in c57bl/6 mice: an immuno-histologic study

ABSTRACT BACKGROUND: Helicobacter pylori (H. pylori) has been introduced by since 1983 by Marshal and Warren to play the main role in the pathophysiology of gastritis and gastric ulcers. Almost half of the world population1 is infected by H. pylori. Current therapeutic regimen against H. pylori includes the use of a proton pump inhibitor plus two or more antibiotics. However, the efficacy of this regimen is decreasing mainly due to antibiotic resistance and side effects of medications. This fact has resulted in public interest in other therapeutic options and the role of probiotics merits special attention in this regard. OBJECTIVE: This study aims to evaluate the efficacy of honey-derived Lactobacillus rhamnosus on H. pylori-induced gastric inflammation and gastro-intestinal infection in C57BL/6 Mice. METHODS: The 24 C57BL/6 Mice were randomly divided into three groups of eight mice each. All the mice were fed with 1cc suspension containing 5*1010 CFU/ mL of ATCC43504 strains of H. pylori for 3 consecutive days, twice daily via polyethylene gavage tubes. At the end of 4th week, infection with H. pylori was confirmed with stool Ag (ELISA) and following sacrifice of one mouse from each group, histopathologic study confirmed gastritis. The groups were subjected to different therapies as stated, 1: without Bismuth (Bi), Omeprazole (Om) and L. rhamnosus prescription, 2: Bi, Om and Clarithromycin (Cl) and 3: Bi, Om plus 1cc of suspension of 109 CFU/mL of L. rhamnosus. After 2 weeks, the stool was analyzed for Ag and the mice were sacrificed for evaluation of histopathologic changes. RESULTS: Treatment with L. rhamnosus group provided Zero titer of stool Ag and was associated with improved gastric inflammation in all subjects, similar to the clarithromycin group. CONCLUSION: Honey-derived L. rhamnosus probiotics provides similar results as clarithromycin in terms of improvement of H. pylori infection and gastritis in C57BL/6 Mice model, without its cons of antibiotic resistance.

RESUMO CONTEXTO: O Helicobacter pylori (H. pylori) foi reconhecido em 1983 por Marechal e Warren como protagonista principal na fisiopatologia de gastrite e úlceras gástricas. Quase metade da população mundial está infectada por H. pylori. O regime terapêutico atual contra H. pylori inclui o uso de um inibidor da bomba de prótons associada a dois ou mais antibióticos. No entanto, a eficácia deste regime está diminuindo principalmente devido à resistência aos antibióticos e efeitos colaterais de medicamentos. Este fato resultou no interesse público em outras opções terapêuticas e o papel dos probióticos merece atenção especial a este respeito. OBJETIVO: Este estudo visa avaliar a eficácia do mel-derivado do Lactobacillus rhamnosus na inflamação gástrica e infecção gastrointestinal H. pylori-induzida em camundongos C57Bl/6. MÉTODOS: Vinte e quatro camundongos C57Bl/6 foram divididos aleatoriamente em três grupos de oito camundongos cada. Todos os ratos foram alimentados com suspensão de 1cc contendo 5*1010 UFC/mL de cepas ATCC43504 de H. pylori por 3 dias consecutivos, duas vezes por dia através de gavagem por tubos de polietileno. No final da 4ª semana, a infecção com H. pylori foi confirmada pelo antígeno fecal (ELISA) e após o sacrifício de um rato de cada grupo, o estudo histopatológico confirmou gastrite. Os grupos foram submetidos a diferentes terapias, como indicado, 1: sem prescrição de bismuto (BI), Omeprazol (Om) e L. rhamnosus, 2: Bi, Om e claritromicina (CL) e 3: Bi, Om mais 1cc de suspensão de 109 UFC/mL de L. rhamnosus. Após 2 semanas, as fezes foram analisadas para o antígeno e os ratos foram sacrificados para a avaliação das alterações histopatológicas. RESULTADOS: O tratamento com o grupo L. rhamnosus forneceu o título zero de antígeno e foi associado com a inflamação gástrica melhorada em todos os camundongos, similar ao grupo claritromicina. CONCLUSÃO: O probiótico mel-derivado L. rhamnosus fornece resultados semelhantes ao da claritromicina em termos de melhoria da infecção H. pylori e gastrite em C57Bl/6 camundongos modelos, sem os inconvenientes de resistência aos antibióticos.