Impact of Helicobacter pylori infection on fluid duodenal microbial community structure and microbial metabolic pathways

Helicobacter pylori and arsenic co-exposure Intensify gastric barrier damage and serum metabolic disorder

Environmental arsenic exposure and Helicobacter pylori (H. pylori) infection are widespread public health concerns, yet their combined effects on gastric pathophysiology remain poorly understood. This study investigated the impact of H. pylori infection and arsenic co-exposure on gastric barrier integrity, oxidative stress, and serum metabolic profiles using a murine model. Mice were divided into control, single-exposure (arsenic), and multiple exposure group (H. pylori infection and arsenic exposure). Gastric barrier function was assessed via immunofluorescence staining of ZO-1 and occludin proteins. Untargeted metabolomics, including PCA, PLS-DA, and KEGG pathway enrichment analyses, were employed to characterize serum metabolic alterations. Gene expression levels of IL-18, Nrf2, Keap1, Cat, Sod1, and Hmox1 in gastric tissues were quantified by qRT-PCR, with Spearman correlation analysis to evaluate metabolite-gene expression relationships. Fluorescence intensity of ZO-1 and occludin was significantly reduced in H. pylori-infected mice, with further deterioration under arsenic co-exposure. Metabolomic profiling revealed distinct serum metabolic perturbations across groups, with the multiple exposure group exhibiting more pronounced fluctuations in metabolite levels (e.g., lipids, amino acids, and peptides) and greater pathway diversity compared to single exposure groups. qRT-PCR analysis demonstrated synergistic upregulation of oxidative stress (Nrf2, Hmox1) and inflammatory (IL-18) markers in the multiple exposure group. Spearman correlation analysis identified significant associations between specific metabolites (e.g., acylcarnitines, bile acids) and antioxidant gene expression, suggesting bidirectional interactions between systemic metabolism and gastric oxidative responses. This study establishes a murine model of H. pylori infection and arsenic co-exposure, revealing synergistic disruption of gastric barrier function, oxidative homeostasis, and metabolic regulation. These findings provide critical insights into the pathophysiological interplay between microbial infection and environmental toxicants, highlighting potential therapeutic targets for mitigating combined exposure risks.

Bioaccessible Bread Melanoidins Modulate Oxidative Stress, Reduce Inflammation and Suppress Adhesion of Helicobacter pylori to Caco-2 Cells

Background/Objectives: Helicobacter pylori is a major contributor to gastric infections; it is prevalent in humans and associated with gastrointestinal diseases. In recent years, the increase in antimicrobial resistance has contributed to the need for alternative approaches, prompting interest in natural products with antimicrobial and antivirulence properties. This study investigated the effect of bioaccessible melanoidins from common and soft bread crust against H. pylori infection. Methods: Melanoidins were extracted using dead-end ultrafiltration, and bioaccessible fractions were obtained through in vitro digestion. The bactericidal effect of melanoidins was assessed at 2% and 4% concentrations over 24 and 48 h. The effect on H. pylori adhesion of 100 μg/mL and 200 μg/mL of gastric and intestinal bioaccessible fractions of melanoidins was evaluated in Caco-2 cells. Results: The bactericidal effect of melanoidins revealed significant efficacy, with a greater effect for soft bread melanoidins. The gastric fractions exhibited a higher inhibitory effect, which is crucial for gastric mucosa, the primary site of H. pylori infection. Both bioaccessible fractions showed anti-inflammatory and antioxidant effects against H. pylori-induced inflammation, particularly in the gastric fractions. This was evidenced by a reduction in interleukin-6 and interleukin-8 release and an enhancement in interleukin-10 release. The observed reduction in reactive oxygen species (ROS) and the maintenance of glutathione levels indicate an improved redox status. Conclusions: This study emphasizes the potential of melanoidins, especially from soft bread, as bioactive compounds against H. pylori, offering insights for future functional food development.

Impacts of Helicobacter pylori infection and eradication on gastrointestinal microbiota: An up-to-date critical review and future perspectives

ABSTRACT

Helicobacter pylori ( H. pylori ) infects approximately half of the population worldwide and causes chronic gastritis, peptic ulcers, and gastric cancer. Test-and-treat strategies have been recommended for the prevention of H. pylori -associated diseases. Advancements in high-throughput sequencing technologies have broadened our understanding of the complex gastrointestinal (GI) microbiota and its role in maintaining host homeostasis. Recently, an increasing number of studies have indicated that the colonization of H. pylori induces dramatic alterations in the gastric microbiota, with a predominance of H. pylori and a reduction in microbial diversity. Dysbiosis of the gut microbiome has also been observed after H. pylori infection, which may play a role in the development of colorectal cancer. However, there is concern regarding the impact of antibiotics on the gut microbiota during H. pylori eradication. In this review, we summarize the current literature concerning how H. pylori infection reshapes the GI microbiota and the underlying mechanisms, including changes in the gastric environment, immune responses, and persistent inflammation. Additionally, the impacts of H. pylori eradication on GI microbial homeostasis and the use of probiotics as adjuvant therapy are also discussed. The shifts in the GI microbiota and their crosstalk with H. pylori  may provide potential targets for H. pylori -related gastric diseases and extragastric manifestations.

Small intestinal microbiota: from taxonomic composition to metabolism

The small intestinal microbiota (SIM) is essential for gastrointestinal health, influencing digestion, immune modulation, and nutrient metabolism. Unlike the colonic microbiota, the SIM has been poorly characterized due to sampling challenges and ethical considerations. Current evidence suggests that the SIM consists of five core genera and additional segment-specific taxa. These bacteria closely interact with the human host, regulating nutrient absorption and metabolism. Recent work suggests the presence of two forms of small intestinal bacterial overgrowth, one dominated by oral bacteria (SIOBO) and a second dominated by coliform bacteria. Less invasive sampling techniques, omics approaches, and mechanistic studies will allow a more comprehensive understanding of the SIM, paving the way for interventions engineering the SIM towards better health.

Alterations of the duodenal mucosal microbiome in patients with metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as nonalcoholic fatty liver disease (NAFLD), is associated with altered gut microbiota; however, there has been a focus on fecal samples, which are not representative of the entire digestive tract. Mucosal biopsies of the descending duodenum were collected. Five regions of the 16S rRNA gene were amplified and sequenced. Other assessments conducted on the study subjects included body mass index, transient elastography, liver enzymes, and lipid profile. Fifty-one subjects (36 with MASLD and 15 controls) were evaluated. There was no significant difference between the two groups regarding alpha- or beta-diversity of the duodenal mucosal microbiota. Linear discriminant analysis effect size (LEfSe) analysis showed that the genera Serratia and Aggregatibacter were more abundant in the duodenal mucosa of patients with MASLD, whereas the duodenal mucosal microbiota of the healthy controls was enriched with the genus Petrobacter. PICRUSt2 analysis revealed that genes associated with amino acid degradation and carboxylate degradation were significantly enriched in the duodenal mucosal microbiota of patients with MASLD. Our findings reveal the duodenal mucosal microbiota in patients with MASLD, which could contribute to future studies investigating the causal relationship between duodenal microbiota and MASLD.

Future Nanotechnology-Based Strategies for Improved Management of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) is a recalcitrant pathogen, which can cause gastric disorders. During the past decades, polypharmacy-based regimens, such as triple and quadruple therapies have been widely used against H. pylori. However, polyantibiotic therapies can disturb the host gastric/gut microbiota and lead to antibiotic resistance. Thus, simpler but more effective approaches should be developed. Here, some recent advances in nanostructured drug delivery systems to treat H. pylori infection are summarized. Also, for the first time, a drug release paradigm is proposed to prevent H. pylori antibiotic resistance along with an IVIVC model in order to connect the drug release profile with a reduction in bacterial colony counts. Then, local delivery systems including mucoadhesive, mucopenetrating, and cytoadhesive nanobiomaterials are discussed in the battle against H. pylori infection. Afterward, engineered delivery platforms including polymer-coated nanoemulsions and polymer-coated nanoliposomes are poposed. These bioinspired platforms can contain an antimicrobial agent enclosed within smart multifunctional nanoformulations. These bioplatforms can prevent the development of antibiotic resistance, as well as specifically killing H. pylori with no or only slight negative effects on the host gastrointestinal microbiota. Finally, the essential checkpoints that should be passed to confirm the potential effectiveness of anti-H. pylori nanosystems are discussed.

Therapeutic Approach Targeting Gut Microbiome in Gastrointestinal Infectious Diseases

While emerging evidence highlights the significance of gut microbiome in gastrointestinal infectious diseases, treatments like Fecal Microbiota Transplantation (FMT) and probiotics are gaining popularity, especially for diarrhea patients. However, the specific role of the gut microbiome in different gastrointestinal infectious diseases remains uncertain. There is no consensus on whether gut modulation therapy is universally effective for all such infections. In this comprehensive review, we examine recent developments of the gut microbiome's involvement in several gastrointestinal infectious diseases, including infection of Helicobacter pylori, Clostridium difficile, Vibrio cholerae, enteric viruses, Salmonella enterica serovar Typhimurium, Pseudomonas aeruginosa Staphylococcus aureus, Candida albicans, and Giardia duodenalis. We have also incorporated information about fungi and engineered bacteria in gastrointestinal infectious diseases, aiming for a more comprehensive overview of the role of the gut microbiome. This review will provide insights into the pathogenic mechanisms of the gut microbiome while exploring the microbiome's potential in the prevention, diagnosis, prediction, and treatment of gastrointestinal infections.

The regulation roles of miRNAs in Helicobacter pylori infection

Helicobacter pylori is a kind of Gram-negative bacteria that parasitizes on human gastric mucosa. Helicobacter pylori infection is very common in human beings, which often causes gastrointestinal diseases, including chronic gastritis, duodenal ulcer and gastric cancer. MicroRNAs are a group of endogenous non-coding single stranded RNAs, which play an important role in cell proliferation, differentiation, autophagy, apoptosis and inflammation. In recent years, relevant studies have found that the expression of microRNA is changed after Helicobacter pylori infection, and then regulate the biological process of host cells. This paper reviews the regulation role of microRNAs on cell biological behavior through different signal pathways after Helicobacter pylori infection.

Disrupted microbiota-barrier-immune interaction in phthalates-mediated barrier defect in the duodenum

As one of the most used phthalates, Di (2-ethylhexyl) phthalate (DEHP) is a widespread environmental contaminant. Extremely persistent plastic can enter the food chain of animals through the aquatic environment, affect metabolic pathways and cause damage to the digestive system. But the molecular mechanism of its toxic effects on the duodenum in birds has not been elucidated. To investigate the toxicity of phthalates in the duodenum, quails were gavaged with 250, 500, and 750 mg/kg doses of DEHP for 45 days, and water and oil control groups were retained. This study revealed that subchronic exposure to DEHP could lead to duodenal barrier defect in quail. The damage to duodenum was reflected in a reduction in V/C and tight junction proteins. Moreover, DEHP also led to a breakdown of antimicrobial defenses through the flora derangement, which acted as a biological barrier. The massive presence of Lipopolysaccharide (LPS) led to the activation of TLR4 receptors. In addition, DEHP activated oxidative stress, which synergized the inflammatory response induced by the TLR4-NFκB pathway, and further promoted duodenum damage. This study provides a base for the further effect of phthalates on the microbiota-barrier-immune interaction.

The Role of Gastrointestinal Microbiota in Functional Dyspepsia: A Review

Functional dyspepsia is a clinically common functional gastrointestinal disorder with a high prevalence, high impact and high consumption of medical resources. The microbiota in the gastrointestinal tract is a large number of families and is one of the most complex microbial reservoirs in the human body. An increasing number of studies have confirmed the close association between dysbiosis of the gastrointestinal microbiota and the occurrence and progression of functional dyspepsia. Therefore, we reviewed the role of dysbiosis of the gastrointestinal microbiota, H. pylori infection and gastrointestinal microbiota metabolites in functional dyspepsia, focusing on the possible mechanisms by which dysbiosis of the gastrointestinal microbiota contributes to the pathogenesis of functional dyspepsia. Several studies have confirmed that dysbiosis of the gastrointestinal microbiota may cause the occurrence and progression of functional dyspepsia by disrupting the biological barrier of the intestinal mucosa, by disturbing the immune function of the intestinal mucosa, or by causing dysregulation of the microbial-gut-brain axis. Probiotics and antibiotics have also been chosen to treat functional dyspepsia in clinical studies and have shown some improvement in the clinical symptoms. However, more studies are needed to explore and confirm the relationship between dysbiosis of the gastrointestinal microbiota and the occurrence and progression of functional dyspepsia, and more clinical studies are needed to confirm the therapeutic efficacy of microbiota modulation for functional dyspepsia.