Gastric juice: a barrier against infectious diseases

Dual-State Emissive and Substituent-Tunable pH-Sensitive Bis-Heterocyclic Fluorescent Probes

A library of fluorescent molecules based on imidazopyridine linked with benzothiazole and benzimidazole was assessed for pH sensitivity and the effect of substituents thereon, also leading to dual-state emission. A broad range of pH (1-13) was evaluated, where the benzothiazole-based (BnTA) compounds responded in acidic pH, whereas the benzimidazole-based (BnIm) compounds behaved differently at different pH with recognizable color change on shifting from acidic to neutral and then to basic. NMR titrations revealed the effect of substituents on governing the site of protonation and deprotonation. Further, the mechanism of fluorescence was comprehended through theoretical calculations. On assessing the solid state fluorescence briefly, 2e showed mechanochromic behavior, showing green fluorescence in the solid state, which vanished upon grinding, and upon fuming with acetone, the fluorescence turned yellowish orange, which reverted to the initial fluorescence upon long-term exposure of acetone. The cellular uptake and fluorescence response of 2l in pH were also evaluated. The colocalization experiment suggested that 2l crossed the nuclear membrane and stained the nucleus, showing its possible in vitro application. The compound serves as a potential lead for other applications likewise, such as optoelectronics, data encryption, and pH sensors.

Characterizing the oral and gastrointestinal microbiome associated with healthy aging: insights from long-lived populations in Northeastern China

The oral and gastrointestinal (GI) tract microbiota in humans is susceptible to geographical influences and represents vital factors impacting healthy aging. The northeastern region of China, characterized by distinct dietary and climatic conditions, significantly influences the human microbiome composition. However, the microbial structure of the entire long-lived population in this area has not been evaluated. This study recruited a cohort of 142 individuals aged 55-102 residing in Northeast China, and their oral and gut microbiota were evaluated using full-length 16S rRNA gene amplicon sequencing. The results indicate that the oral and GI tract microbiota of long-lived individuals showed reduced microbial taxonomic richness and evenness compared to sub-longevity individuals. With aging, the core species experience a gradual decline in abundance, while subordinate species show an increase. The long-lived population exhibited a heightened ability to enrich beneficial bacteria including Akkermansia, Alistipes, Parabacteroides, and Eubacterium coprostanoligenes in the GI tract, which are associated with host metabolism and have the potential to act as probiotics, reducing the risks of unhealthy aging in the northeast population. Bifidobacterium sp. and Lactobacillus salivarius have been found to coexist in both the oral cavity and the GI tract of long-lived individuals. We hypothesize that beneficial bacterial taxa from the oral cavity colonize the GI tract more extensively in long-lived individuals compared to those with a shorter lifespan. These findings pave the way for identifying probiotic strains that can promote healthy aging in Northeast China.

Bowel preparation before colonoscopy: Consequences, mechanisms, and treatment of intestinal dysbiosis

The term "gut microbiota" primarily refers to the ecological community of various microorganisms in the gut, which constitutes the largest microbial community in the human body. Although adequate bowel preparation can improve the results of colonoscopy, it may interfere with the gut microbiota. Bowel preparation for colonoscopy can lead to transient changes in the gut microbiota, potentially affecting an individual's health, especially in vulnerable populations, such as patients with inflammatory bowel disease. However, measures such as oral probiotics may ameliorate these adverse effects. We focused on the bowel preparation-induced changes in the gut microbiota and host health status, hypothesized the factors influencing these changes, and attempted to identify measures that may reduce dysbiosis, thereby providing more information for individualized bowel preparation for colonoscopy in the future.

Herbal Extracts Mixed with Essential Oils: A Network Approach for Gastric and Intestinal Motility Disorders

BACKGROUND

Three herbal extracts (Asparagus racemosus Willd., Tabebuia avellanedae Lorentz, and Glycyrrhiza glabra L.) were mixed with three essential oils (Foeniculum vulgare Mill., Mentha piperita L., and Pimpinella anisum L.) to formulate a product (HEMEO) whose active compounds include saponins and steroids in Asparagus racemosus, known for their anti-inflammatory properties; glycyrrhizin and flavonoids in Glycyrrhiza glabra, which exhibit gastroprotective and antispasmodic effects; menthol in Mentha piperita, contributing with antispasmodic and antimicrobial properties; and anethole and polyphenols in Pimpinella anisum, which modulate intestinal motility and offer antimicrobial activity.

OBJECTIVE

HEMEO was formulated for applications in intestinal motility disorders.

METHODS

HEMEO was evaluated for spontaneous and induced motility effects in isolated guinea pig ileum, colon, and stomach. Ex vivo experiments were conducted using LabChart software v7.0, and the product's antibacterial action against Helicobacter pylori and its antioxidant effects were assessed through disc diffusion and FRAP assays. The presence of the volatile compounds in the formulation was confirmed by GC-MS analysis; the TPC of HEMEO, determined using the Folin-Ciocalteu method, was 9.925 ± 0.42 mg GAE/g.

CONCLUSIONS

HEMEO showed a phenolic content correlated with its antioxidant potential and in addition inhibited H. pylori growth and demonstrated notable antioxidant properties, suggesting its role as a supportive agent in digestive processes and in managing motility disorders.

Gut Microbiome Changes After Neoadjuvant Chemotherapy and Surgery in Patients with Gastric Cancer

BACKGROUND/OBJECTIVES

Neoadjuvant chemotherapy (NAC) followed by radical gastrectomy is the current standard approach for locally advanced gastric cancer (GC) in the West. Both NAC and gastrectomy can significantly influence the gut microbiome, potentially leading to clinically significant changes. However, no longitudinal studies to date support this hypothesis. This study investigates gut microbiome changes throughout GC treatment, including NAC and gastrectomy.

METHODS

This longitudinal observational study included GC patients undergoing NAC followed by gastrectomy. Fecal microbiome composition, intestinal inflammation (fecal calprotectin), and gut permeability (LBP, sCD14) markers were investigated at baseline, after NAC, and after gastrectomy.

RESULTS

A total of 38 patients were included in the study. The results showed that NAC did not affect the gut microbiome composition at the phylum level. In contrast, radical gastrectomy led to an increased abundance of Bacteroidetes and Proteobacteria and a decreased abundance of Firmicutes and Actinobacteria. Furthermore, NAC alone did not impact alpha or beta diversity, while a combination of NAC and gastrectomy significantly influenced both. After gastrectomy, the gut microbiome composition analysis also revealed enrichment of oralization-associated bacterial species such as Escherichia-Shigella, Streptococcus equinus, uncultured Streptococcus species, and species from the Enterobacteriaceae family. Intestinal inflammation and gut permeability markers did not significantly change throughout the treatment.

CONCLUSIONS

The radical treatment of advanced GC with NAC and radical surgery has long-term effects on the gut microbiome, characterized by gut microbiome oralization. These sustained alterations primarily stem from the radical gastrectomy rather than the NAC. Since previous studies have linked oralization-associated dysbiosis to various gastrointestinal symptoms, this study highlights the gut microbiome as a potential therapeutic target to enhance the quality of life in long-term survivors following gastrectomy.

The oral-gut microbiome axis in health and disease

The human body hosts trillions of microorganisms throughout many diverse habitats with different physico-chemical characteristics. Among them, the oral cavity and the gut harbour some of the most dense and diverse microbial communities. Although these two sites are physiologically distinct, they are directly connected and can influence each other in several ways. For example, oral microorganisms can reach and colonize the gastrointestinal tract, particularly in the context of gut dysbiosis. However, the mechanisms of colonization and the role that the oral microbiome plays in causing or exacerbating diseases in other organs have not yet been fully elucidated. Here, we describe recent advances in our understanding of how the oral and intestinal microbiota interplay in relation to their impact on human health and disease.

The influence of Helicobacter pylori, proton pump inhibitor, and obesity on the gastric microbiome in relation to gastric cancer development

Helicobacter pylori infection is still the main risk factor for the development of gastric cancer (GC). We explore the scientific evidence for the role of the gastric microbiome beyond Helicobacter pylori (H. pylori) in gastric carcinogenesis. The composition of the gastric microbiome in healthy individuals, in presence and absence of H. pylori infection, in proton pump inhibitor (PPI)-users, obese individuals, and GC patients was investigated. Possible mechanisms for microbial involvement, limitations of available research and options for future studies are provided. A common finding amongst studies was increased levels of Streptococcus, Prevotella, Neisseria, and Actinomyces in healthy individuals or those with H. pylori-negative gastritis. In PPI-users the risk for GC increases with the treatment duration, and the gastric microbiome shifts, with the most consistent increase in the genus Streptococcus. Similarly, in obese individuals, Streptococcus was the most abundant genus, with an increased risk for cardia GC. The genera Streptococcus, Lactobacillus and Prevotella were found to be more prominent in GC patients in multiple studies. Potential mechanisms of non-H. pylori microbiota contributing to GC are linked to lipopolysaccharide production, contribution to inflammatory pathways, and the formation of N-nitroso compounds and reactive oxygen species. In conclusion, the knowledge of the gastric microbiome in GC is mainly descriptive and based on sequencing of gastric mucosal samples. For a better mechanistic understanding of microbes in GC development, longitudinal cohorts including precancerous lesions, different regions in the stomach, and subtypes of GC, and gastric organoid models for diffuse and intestinal type GC should be employed.

Encapsulation of Saccharomyces spp. for Use as Probiotic in Food and Feed: Systematic Review and Meta-analysis

Probiotics, particularly yeasts from the genus Saccharomyces, are valuable for their health benefits and potential as antibiotic alternatives. To be effective, these microorganisms must withstand harsh environmental conditions, necessitating advanced protective technologies such as encapsulation to maintain probiotic viability during processing, storage, and passage through the digestive system. This review and meta-analysis aims to describe and compare methods and agents used for encapsulating Saccharomyces spp., examining operating conditions, yeast origins, and species. It provides an overview of the literature on the health benefits of nutritional yeast consumption. A bibliographic survey was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. The meta-analysis compared encapsulation methods regarding their viability after encapsulation and exposure to the gastrointestinal tract. Nineteen studies were selected after applying inclusion/exclusion criteria. Freeze drying was found to be the most efficient for cell survival, while ionic gelation was best for maintaining viability after exposure to the gastrointestinal tract. Consequently, the combination of freeze drying and ionic gelation proved most effective in maintaining high cell viability during encapsulation, storage, and consumption. Research on probiotics for human food and animal feed indicates that combining freeze drying and ionic gelation effectively protects Saccharomyces spp.; however, industrial scalability must be considered. Reports on yeast encapsulation using agro-industrial residues as encapsulants offer promising strategies for preserving potential probiotic yeasts, contributing to the environmental sustainability of industrial processes.

Role of Oral Yeast in Replenishing Gastric Mucosa with Yeast and Helicobacter pylori

The relationship between oral and gastric yeasts and their role in the colonization of Helicobacter pylori in the stomach was studied. Four groups of 221, 7, 44, and 10 patients were used for the isolation of H. pylori and oral and gastric yeasts. In Group 1, gastric biopsies were used for the isolation of H. pylori and yeast, rapid urease test (RUT), staining with Gram's and hematoxylin & eosin (H&E), and immunohistochemistry (IHC) methods. In the other three groups, DNAs extracted from H. pylori and yeasts were used for the amplification of H. pylori-specific genes. Wet mounts of yeasts in Group 2 were examined to observe intracellular bacteria and released EVs. Among 221 patients, 65 (29.3%) had oral yeast, 35 (15.8%) H. pylori, and 31 (14%) gastric yeast. Culture of oral yeasts showed a significant correlation with the detection of H. pylori by IHC (10.3%), Gram stain (9%), RUT (6.3%), H&E (4.9%), and culture (4%) (p < 0.05). Gram-stained biopsies showed the occurrence of yeast and H. pylori, and the release of EVs from yeast. Detection of similar H. pylori genes in oral and gastric yeasts from patients in Group 2 showed their common source. Oral yeasts in Groups 3 and 4 also carried H. pylori genes. Wet mount preparations of yeasts showed intracellular bacteria inside the yeast vacuole and the release of EVs that could carry H. pylori. Oral yeast protects its intracellular H. pylori and releases it inside EVs to safely reach gastric mucosa. Yeast, as the environmental reservoir of H. pylori, plays a crucial role in bacterial reinfection after successful eradication.

Dairy-based multi-strain probiotic community successfully mitigated obesity-related gut microbiota dysbiosis in vitro (CoMiniGut)

Introduction. Obesity is a global health concern, affecting individuals of all ages and genders. One promising strategy to combat obesity is by addressing gut microbiota dysbiosis, with probiotics being a reliable intervention. However, single-strain probiotics may not effectively modulate the complex microbial communities in the gut, suggesting the need for multi-strain approaches.Gap Statement. Probiotics are known to benefit gut health; however, the efficacy of single-strain probiotics in modulating gut microbiota is limited. Multi-strain probiotic community (MSPC) may offer a more effective approach for addressing obesity-related gut dysbiosis, but its specific effects on individuals and microbial diversity require further investigation.Aim. This study aimed to evaluate the potential of a dairy-origin MSPC in modulating obesity-related gut microbiota from lean and obese Pakistani volunteers using a simulated CoMiniGut model.Methodology. Gut microbiota from lean and obese volunteers were treated with MSPC in a simulated CoMiniGut system. Bacterial counts, microbial diversity (α- and β-diversity) and microbial community composition were analysed pre- and post-treatment. The impact of MSPC on specific bacterial genera and microbial metabolites was assessed, with statistical significance determined (P≤0.05).Results. The effect of MSPC was individualized, reducing bacterial counts in lean 1 and lean 2 samples, while significantly increasing bacterial counts in obese 2 and obese 3 samples (P≤0.05). MSPC significantly improved α-diversity in lean 2, lean 3, obese 2 and obese 3 samples (P≤0.05). Proteobacteria decreased in the lean group and increased in the obese group post-MSPC treatment. In the lean group, pathogenic bacteria such as Klebsiella, Escherichia and Enterobacter were significantly reduced (P≤0.05), whereas beneficial bacteria like Bifidobacterium and Lactobacillus increased significantly in the obese group (P≤0.05). Among the selected metabolites, only butanoic acid was detected in all tested samples, with MSPC affecting metabolite concentrations and types.Conclusion. MSPC demonstrated a potential for modulating gut microbiota dysbiosis in both lean and obese individuals, with effects on bacterial counts, microbial diversity and metabolite concentrations. MSPC could serve as a promising option for personalized the modulation of gut microbiota in obesity management.

Oral Pathobiont-Derived Outer Membrane Vesicles in the Oral-Gut Axis

Oral pathobionts are essential in instigating local inflammation within the oral cavity and contribute to the pathogenesis of diseases in the gastrointestinal tract and other distant organs. Among the Gram-negative pathobionts, Porphyromonas gingivalis and Fusobacterium nucleatum emerge as critical drivers of periodontitis, exerting their influence not only locally but also as inducers of gut dysbiosis, intestinal disturbances, and systemic ailments. This dual impact is facilitated by their ectopic colonization of the intestinal mucosa and the subsequent mediation of distal systemic effects by releasing outer membrane vesicles (OMVs) into circulation. This review elucidates the principal components of oral pathobiont-derived OMVs implicated in disease pathogenesis within the oral-gut axis, detailing virulence factors that OMVs carry and their interactions with host epithelial and immune cells, both in vitro and in vivo. Additionally, we shed light on the less acknowledged interplay between oral pathobionts and the gut commensal Akkermansia muciniphila, which can directly impede oral pathobionts' growth and modulate bacterial gene expression. Notably, OMVs derived from A. muciniphila emerge as promoters of anti-inflammatory effects within the gastrointestinal and distant tissues. Consequently, we explore the potential of A. muciniphila-derived OMVs to interact with oral pathobionts and prevent disease in the oral-gut axis.

Optimization of Helicobacter pylori Biofilm Formation in In Vitro Conditions Mimicking Stomach

Helicobacter pylori is one of the most common bacterial pathogens worldwide and the main etiological agent of numerous gastric diseases. The frequency of multidrug resistance of H. pylori is growing and the leading factor related to this phenomenon is its ability to form biofilm. Therefore, the establishment of a proper model to study this structure is of critical need. In response to this, the aim of this original article is to validate conditions of the optimal biofilm development of H. pylori in monoculture and co-culture with a gastric cell line in media simulating human fluids. Using a set of culture-based and microscopic techniques, we proved that simulated transcellular fluid and simulated gastric fluid, when applied in appropriate concentrations, stimulate autoaggregation and biofilm formation of H. pylori. Additionally, using a co-culture system on semi-permeable membranes in media imitating the stomach environment, we were able to obtain a monolayer of a gastric cell line with H. pylori biofilm on its surface. We believe that the current model for H. pylori biofilm formation in monoculture and co-culture with gastric cells in media containing host-mimicking fluids will constitute a platform for the intensification of research on H. pylori biofilms in in vitro conditions that simulate the human body.

Unravelling the Oral-Gut Axis: Interconnection Between Periodontitis and Inflammatory Bowel Disease, Current Challenges, and Future Perspective

As the opposite ends of the orodigestive tract, the oral cavity and the intestine share anatomical, microbial, and immunological ties that have bidirectional health implications. A growing body of evidence suggests an interconnection between oral pathologies and inflammatory bowel disease [IBD], implying a shift from the traditional concept of independent diseases to a complex, reciprocal cycle. This review outlines the evidence supporting an 'oral-gut' axis, marked by a higher prevalence of periodontitis and other oral conditions in IBD patients and vice versa. We present an in-depth examination of the interconnection between oral pathologies and IBD, highlighting the shared microbiological and immunological pathways, and proposing a 'multi-hit' hypothesis in the pathogenesis of periodontitis-mediated intestinal inflammation. Furthermore, the review underscores the critical need for a collaborative approach between dentists and gastroenterologists to provide holistic oral-systemic healthcare.

Vonoprazan-associated Clostridioides difficile infection: an analysis of the Japanese Adverse Drug Event Report and the FDA Adverse Event Reporting System

Background

Prolonged or excessive use of acid suppressants may increase the risk of Clostridioides difficile infection (CDI) by altering the intestinal microecosystem. Vonoprazan, a novel potassium-competitive acid blocker, exhibits a faster and more sustained acid-suppressive effect than proton pump inhibitors (PPIs). Therefore, vonoprazan may have a greater impact on the gut microbiota, potentially resulting in CDI.

Objectives

This study aimed to explore the potential relationship between acid suppressants and CDI by the Japan Adverse Drug Event Report (JADER) and the FDA Adverse Event Reporting System (FAERS) databases.

Design

A retrospective analysis of the JADER and FAERS databases was examined by disproportionality analysis.

Methods

We performed signal detection analyses of CDI induced by vonoprazan and PPIs using the JADER and FAERS databases. The association between acid suppressants and CDI was calculated using the reporting odds ratio (ROR) and corresponding 95% confidence interval (95% CI). When the lower limit of the 95% CI is exceeded by 1, the association is considered statistically significant.

Results

In the JADER database, the ROR (95% CI) for vonoprazan and PPIs based on suspect drug reports was 15.84 (12.23-20.50) and 2.51 (1.92-3.28), respectively. In the FAERS database, the ROR (95% CI) for vonoprazan and PPIs based on primary and secondary suspect drug reports was 11.50 (6.36-20.82) and 1.42 (1.34-1.51), respectively. Subgroup analysis showed that elderly patients aged 60 years and older were more strongly associated with CDI. The ROR (95% CI) for vonoprazan and PPIs in patients aged 60 years and older in the JADER database was 15.35 (11.59-20.33) and 1.65 (1.14-2.39), respectively. Similarly, the ROR (95% CI) for vonoprazan and PPIs in the FAERS database was 12.56 (6.26-25.20) and 1.43 (1.31-1.57), respectively. Excluding the effect of Helicobacter pylori (H. pylori) infection, the use of acid suppressants was still associated with CDI.

Conclusion

While signal detection analysis based on the JADER and FAERS databases could not establish causality, our study demonstrated that both vonoprazan and PPIs were significantly associated with CDI. Vonoprazan showed a stronger association with CDI in both databases.

One-step formation of polymorphous sperm-like microswimmers by vortex turbulence-assisted microfluidics

Microswimmers are considered promising candidates for active cargo delivery to benefit a wide spectrum of biomedical applications. Yet, big challenges still remain in designing the microswimmers with effective propelling, desirable loading and adaptive releasing abilities all in one. Inspired by the morphology and biofunction of spermatozoa, we report a one-step formation strategy of polymorphous sperm-like magnetic microswimmers (PSMs) by developing a vortex turbulence-assisted microfluidics (VTAM) platform. The fabricated PSM is biodegradable with a core-shell head and flexible tail, and their morphology can be adjusted by vortex flow rotation speed and calcium chloride solution concentration. Benefiting from the sperm-like design, our PSM exhibits both effective motion ability under remote mag/netic actuation and protective encapsulation ability for material loading. Further, it can also realize the stable sustain release after alginate-chitosan-alginate (ACA) layer coating modification. This research proposes and verifies a new strategy for the sperm-like microswimmer construction, offering an alternative solution for the target delivery of diverse drugs and biologics for future biomedical treatment. Moreover, the proposed VTAM could also be a general method for other sophisticated polymorphous structures fabrication that isn't achievable by conventional laminar flow.

Effects of intrinsic characteristics of Salmonella enterica strains isolated from foods and humans, and their interaction with food matrices during simulated gastric conditions

The stomach's acidic pH is a crucial barrier against foodborne pathogens such as Salmonella enterica. This study investigated the survival of S. enterica under simulated oral and gastric conditions (SGC; pH 2 for 120 min) as a function of intrinsic pathogen characteristics and food matrix. Fifty-seven S. enterica strains isolated from food and human infections (previously characterized by serotype, virulotype, multi-drug resistance, isolation source, and isolation season) were subjected to SGC using water as a vehicle. Population reduction among the 57 isolates ranged from 2.7 to 4.7 log CFU, revealing that human isolates were inactivated less than food isolates (p = 0.0008). Among food strains, strains isolated during the cold season (food sampled from December to February) displayed the highest reduction (p = 0.00002). Six representatives of the 57 S. enterica strains were selected according to their virulotype and antimicrobial profile. They were further used to evaluate their survival under SGC in four food matrices (water, mango, tomato, and chicken), measuring S. enterica at 30 min intervals. The strains in chicken showed the lowest reduction and inactivation rate (1.42 ± 0.35 log CFU; 0.03 ± 0.005 min-1), followed by tomato (3.75 ± 0.57 log CFU; 0.15 ± 0.02 min-1), water (4.23 ± 0.27 log CFU; 0.17 ± 0.02 min-1), and mango (4.49 ± 0.39 log CFU; 0.17 ± 0.03 min-1). These data suggest that not all S. enterica strains have the same ability to survive under SGC, influencing the probability of arriving into the small intestine.

H. Pylori Treatment in the COVID-19 Era. What Have We Learned So Far?

PURPOSE OF REVIEW

CoronaVirus Disease of 2019 (COVID-19) has negatively influenced the management of multiple conditions in regards to the gastroenterology patient. An equivalent change in the management of Helicobacter pylori (H. pylori)-related diseases was reported, as practically no eradication treatment was offered during most of the pandemic. Given the scarcity of published data, we performed a literature review trying to elucidate the effect of COVID-19 on H. pylori treatment.

RECENT FINDINGS

COVID-19 has produced more questions than answers as to the outcome of COVID-19 in H. Pylori infected patients, post-COVID-19 patients treated for H. pylori, acid suppression and COVID-19 incidence and outcomes, and H. pylori eradication treatment in patients having recovered from COVID-19. We strongly believe that this scientific uncertainty produced by the COVID-19 pandemic has set up the stage for an incremental change in H. pylori treatment as COVID-19 has offered us the chance to speed up how we will, in the near future, approach patients with a possible Η. pylori infection.

Creating a Framework for Treating Autoimmune Gastritis-The Case for Replacing Lost Acid

Autoimmune gastritis (AIG) is characterized by the destruction of gastric parietal cells, resulting in hypochlorhydria and eventual achlorhydria, as oxyntic glands in the corpus are destroyed and become atrophic. The permanent loss of gastric acid has many impacts-both theoretical and documented. The most concerning of these are hypergastrinemia and increased N-nitroso compounds, both of which increase the risk of gastric cancers. While known deficiencies of B12 and iron are often replaced in AIG, acid is not. Moreover, patients with AIG are often prescribed acid suppression for a stomach that is decidedly no longer acidic, worsening the sequelae of gastric atrophy. Betaine hydrochloride (BHCL) is a short-acting acidifying agent, available over the counter in capsule form. Mealtime acid supplementation has an historic basis and could ameliorate many AIG-related gastrointestinal symptoms. Theoretically, acidification could also reduce the potential for hypergastrinemia and the production of N-nitroso compounds, consequently reducing the risk of gastric cancers. Supplemental vitamin C may also help in preventing gastric N-nitroso formation, regardless of the gastric pH. This narrative review describes the functions of gastric acid in gastrointestinal and immune health, documents the effects of hypochlorhydria in AIG, and proposes potential options for safely re-establishing the acid milieu of the stomach for patients with AIG.

An accurate aging clock developed from large-scale gut microbiome and human gene expression data

Accurate measurement of the biological markers of the aging process could provide an "aging clock" measuring predicted longevity and enable the quantification of the effects of specific lifestyle choices on healthy aging. Using machine learning techniques, we demonstrate that chronological age can be predicted accurately from (1) the expression level of human genes in capillary blood and (2) the expression level of microbial genes in stool samples. The latter uses a very large metatranscriptomic dataset, stool samples from 90,303 individuals, which arguably results in a higher quality microbiome-aging model than prior work. Our analysis suggests associations between biological age and lifestyle/health factors, e.g., people on a paleo diet or with IBS tend to have higher model-predicted ages and people on a vegetarian diet tend to have lower model-predicted ages. We delineate the key pathways of systems-level biological decline based on the age-specific features of our model.

Prevalence of multi-antimicrobial resistant non-typhoidal Salmonella isolated from filth flies at wet markets in Klang, Malaysia, and their survival in the simulated gastric fluid

Filth flies at wet markets can be a vector harbouring multiple antimicrobial-resistant (MAR) nontyphoidal Salmonella (NTS), and such strains are a significant threat to public health as they may cause severe infections in humans. This study aims to investigate the prevalence of antimicrobial-resistant NTS, especially Salmonella Enteritidis and S. Typhimurium harboured by filth flies at wet markets, and investigate their survival in the simulated gastric fluid (SGF). Filth flies (n = 90) were captured from wet markets in Klang, Malaysia, and processed to isolate Salmonella spp. The isolates (n = 16) were identified using the multiplex-touchdown PCR and assessed their antimicrobial susceptibility against 11 antimicrobial agents. Finally, three isolates with the highest MAR index were subjected to SGF survival tests. It was observed that 17.8 % of flies (n = 16/90) harbouring Salmonella, out of which 10 % (n = 9/90) was S. Enteritidis, 2.2 % (n = 2/90) was S. Typhimurium, and 5.6 % was unidentified serotypes of Salmonella enterica subsp. I. 43.8 % (n = 7/16) were confirmed as MAR, and they were observed to be resistant against ampicillin, chloramphenicol, kanamycin, streptomycin, and nalidixic acid. Three strains, F35, F75, and F85 demonstrated the highest MAR index and were able to survive (>6-log10) in the SGF (180 min), indicating their potential virulence and invasiveness. This study provides significant insights into the prevalence and severity of MAR nontyphoidal Salmonella harboured by filth flies in wet markets, which may help inform strategies for controlling the spread and outbreak of foodborne disease.

The oral-gut axis: a missing piece in the IBD puzzle

Inflammatory bowel disease (IBD) is a multifactorial intractable intestinal disease. Focusing on only one facet of the pathogenesis of IBD is insufficient to fully capture the complexity of the disease, and results in limited advance in clinical management. Therefore, it is critical to dissect the interactions amongst the multifarious contributors to the pathogenesis to comprehensively understand its pathology and subsequently improve clinical outcomes. In this context, the systemic interactions between organs, particularly the oral-gut axis mediated by host immune cells and resident microorganisms, have garnered significant attention in IBD research. More specifically, periodontal disease such as periodontitis has been implicated in augmenting intestinal inflammation beyond the confines of the oral cavity. There is mounting evidence suggesting that potentially harmful oral resident bacteria, termed pathobionts, and pro-inflammatory immune cells from the oral mucosa can migrate to the gastrointestinal tract, thereby potentiating intestinal inflammation. This article aims to provide a holistic overview of the causal relationship between periodontal disease and intestinal inflammation. Furthermore, we will discuss potential determinants that facilitate the translocation of oral pathobionts into the gut, a key event underpinning the oral-gut axis. Unraveling the complex dynamics of microbiota and immunity in the oral-gut continuum will lead to a better understanding of the pathophysiology inherent in both oral and intestinal diseases and the development of prospective therapeutic strategies.

Efficacy of Different Encapsulation Techniques on the Viability and Stability of Diverse Phage under Simulated Gastric Conditions

Salmonella causes a range of diseases in humans and livestock of considerable public health and economic importance. Widespread antimicrobial use, particularly in intensively produced livestock (e.g., poultry and pigs) may contribute to the rise of multidrug-resistant Salmonella strains. Alternative treatments such as bacteriophages have shown promise when used to reduce the intestinal carriage of Salmonella in livestock. However, the digestive enzymes and low pH encountered in the monogastric GI tract can significantly reduce phage viability and impact therapeutic outcomes. This study deployed alginate-carrageenan microcapsules with and without CaCO3 to protect a genomically diverse set of five Salmonella bacteriophages from simulated gastrointestinal conditions. None of the unprotected phage could be recovered following exposure to pH < 3 for 10 min. Alginate-carrageenan encapsulation improved phage viability at pH 2-2.5 after exposure for 10 min, but not at pH 2 after 1 h. Including 1% (w/v) CaCO3 in the formulation further reduced phage loss to <0.5 log10 PFU/mL, even after 1 h at pH 2. In all cases, phage were efficiently released from the microcapsules following a shift to a neutral pH (7.5), simulating passage to the duodenum. In summary, alginate-carrageenan-CaCO3 encapsulation is a promising approach for targeted intestinal delivery of genomically diverse Salmonella bacteriophages.

Association Between Proton Pump Inhibitor Use and Spontaneous Bacterial Peritonitis or Hepatic Encephalopathy in Cirrhotic Patients: A Systematic Review and Meta-analysis

Context: There is a link between proton pump inhibitors (PPIs) use and the occurrence of spontaneous bacterial peritonitis (SBP) in cirrhotic patients in some studies; however, in other studies, such a link does not exist. Objectives: The aim of the current systematic review and meta-analysis was to evaluate the association between PPI and the occurrence of SBP or hepatic encephalopathy (HE) in cirrhotic patients. Data Sources: A systematic search of sources was conducted in order to evaluate for any relationship between PPI and the risk of SBP in patients with liver diseases. Medline, Scopus, Ovid, ProQuest, Google Scholar, and Web of Science were searched to find any evidence in this regard from 1980 to November of 2021. Study Selection: The articles were evaluated by two independent reviewers according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses). After deleting the duplicates, first, the titles of the studies were evaluated, and then the full texts were evaluated. Any disagreement between the two researchers was solved by discussion or a third reviewer. Data Extraction: Appropriate Critical Appraisal Checklists of Joanna Briggs Institute (JBI) were used for the quality assessment of eligible studies. Statistical analysis was performed by CMA software (version 2.0), and a P-value of less than 0.05 was considered a significant level. Results: In the systematic search of sources, 3705 articles were identified. Finally, 33 studies were included in this meta-analysis study. A total of 6370 PPI users and 8037 patients in the control group experienced at least one of the complications of liver cirrhosis, including SBP or HE. According to meta-analysis, the risk of SBP or HE in the intervention group was 1.95 times higher than in the control group (RR = 1.95; 95% confidence interval [CI]: 1.53 - 2.48, P < 0.001). Conclusions: The use of PPIs is associated with a higher risk of SBP and HE in cirrhotic patients. However, the quality of included studies in the current systematic review and meta-analysis was moderate, and high-quality studies with a larger sample size are required.

Honokiol, an inducer of sirtuin-3, protects against non-steroidal anti-inflammatory drug-induced gastric mucosal mitochondrial pathology, apoptosis and inflammatory tissue injury

BACKGROUND AND PURPOSE

Mitochondrial oxidative stress, inflammation and apoptosis primarily underlie gastric mucosal injury caused by the widely used non-steroidal anti-inflammatory drugs (NSAIDs). Alternative gastroprotective strategies are therefore needed. Sirtuin-3 pivotally maintains mitochondrial structural integrity and metabolism while preventing oxidative stress; however, its relevance to gastric injury was never explored. Here, we have investigated whether and how sirtuin-3 stimulation by the phytochemical, honokiol, could rescue NSAID-induced gastric injury.

EXPERIMENTAL APPROACH

Gastric injury in rats induced by indomethacin was used to assess the effects of honokiol. Next-generation sequencing-based transcriptomics followed by functional validation identified the gastroprotective function of sirtuin-3. Flow cytometry, immunoblotting, qRT-PCR and immunohistochemistry were used measure effects on oxidative stress, mitochondrial dynamics, electron transport chain function, and markers of inflammation and apoptosis. Sirtuin-3 deacetylase activity was also estimated and gastric luminal pH was measured.

KEY RESULTS

Indomethacin down-regulated sirtuin-3 to induce oxidative stress, mitochondrial hyperacetylation, 8-oxoguanine DNA glycosylase 1 depletion, mitochondrial DNA damage, respiratory chain defect and mitochondrial fragmentation leading to severe mucosal injury. Indomethacin dose-dependently inhibited sirtuin-3 deacetylase activity. Honokiol prevented mitochondrial oxidative damage and inflammatory tissue injury by attenuating indomethacin-induced depletion of both sirtuin-3 and its transcriptional regulators PGC1α and ERRα. Honokiol also accelerated gastric wound healing but did not alter gastric acid secretion, unlike lansoprazole.

CONCLUSIONS AND IMPLICATIONS

Sirtuin-3 stimulation by honokiol prevented and reversed NSAID-induced gastric injury through maintaining mitochondrial integrity. Honokiol did not affect gastric acid secretion. Sirtuin-3 stimulation by honokiol may be utilized as a mitochondria-based, acid-independent novel gastroprotective strategy against NSAIDs.

Inflammation and Digestive Cancer

Chronic inflammation is linked to carcinogenesis, particularly in the digestive organs, i.e., the stomach, colon, and liver. The mechanism of this effect has, however, only partly been focused on. In this review, we focus on different forms of chronic hepatitis, chronic inflammatory bowel disease, and chronic gastritis, conditions predisposing individuals to the development of malignancy. Chronic inflammation may cause malignancy because (1) the cause of the chronic inflammation is itself genotoxic, (2) substances released from the inflammatory cells may be genotoxic, (3) the cell death induced by the inflammation induces a compensatory increase in proliferation with an inherent risk of mutation, (4) changes in cell composition due to inflammation may modify function, resulting in hormonal disturbances affecting cellular proliferation. The present review focuses on chronic gastritis (Helicobacter pylori or autoimmune type) since all four mechanisms may be relevant to this condition. Genotoxicity due to the hepatitis B virus is an important factor in hepatocellular cancer and viral infection can similarly be central in the etiology and malignancy of inflammatory bowel diseases. Helicobacter pylori (H. pylori) is the dominating cause of chronic gastritis and has not been shown to be genotoxic, so its carcinogenic effect is most probably due to the induction of atrophic oxyntic gastritis leading to hypergastrinemia.

Rigidized 3-aminocoumarins as fluorescent probes for strongly acidic environments and rapid yeast vacuolar lumen staining: mechanism and application

Coumarins remain one of the most important groups of fluorescent bio-probes, thanks to their high quantum yields, moderate photostability, efficient cell permeation and low (cyto)toxicity. Herein, we introduce new 3-aminocoumarins as turn-on pH probes under strongly acidic conditions and for indicators capable of significantly improving yeast vacuolar lumen staining compared to the commercial CMAC derivatives. We present the details of the on-off switching mechanism revealed by the TD-DFT and ab initio calculations complemented by a Franck-Condon analysis of the probes' emission profiles.

Colonization of the gastric juice by Candida spp. promotes surgical site infection after hepatectomy

PURPOSE

Candida spp. cause opportunistic infections in conditions of immunodeficiency. Here, we investigated the relationship between colonization of the gastric juice by Candida spp. and surgical site infection (SSI) in hepatectomy.

METHODS

Consecutive hepatectomy cases between November 2019 and April 2021 were enrolled. Gastric juice samples (collected intraoperatively through a nasogastric tube) were cultured. We compared factors related to patient background, blood test findings, surgical findings, and postoperative complications between the Candida + group (positive for colonization of the gastric juice by Candida spp.) and the Candida - group (negative). In addition, we identified the factors that contribute to SSI.

RESULTS

There were 29 and 71 patients in the Candida + and Candida - groups, respectively. The Candida + group was significantly older (average age: Candida + 74 years vs. Candida - 69 years; p = 0.02) and contained more patients negative for the hepatitis B and C virus (Candida + 93% vs. Candida - 69%; p = 0.02). SSI was significantly more common in the Candida + group (Candida + 31% vs. Candida - 9%; p = 0.01). Postoperative bile leakage and colonization of the gastric juice by Candida spp. were independent predictors of SSI.

CONCLUSION

Colonization of the gastric juice by Candida spp. is a risk factor for SSI after hepatectomy.

Simulated Gastric Acid Promotes the Horizontal Transfer of Multidrug Resistance Genes across Bacteria in the Gastrointestinal Tract at Elevated pH Levels

The assessment of factors that can promote the transmission of antibiotic resistance genes (ARGs) across bacteria in the gastrointestinal tract is in great demand to understand the occurrence of infections related to antibiotic-resistant bacteria (ARB) in humans. However, whether acid-resistant enteric bacteria can promote ARG transmission in gastric fluid under high-pH conditions remains unknown. This study assessed the effects of simulated gastric fluid (SGF) at different pH levels on the RP4 plasmid-mediated conjugative transfer of ARGs. Moreover, transcriptomic analysis, measurement of reactive oxygen species (ROS) levels, assessment of cell membrane permeability, and real-time quantitative assessment of the expression of key genes were performed to identify the underlying mechanisms. The frequency of conjugative transfer was the highest in SGF at pH 4.5. Antidepressant consumption and certain dietary factors further negatively impacted this situation, with 5.66-fold and 4.26-fold increases in the conjugative transfer frequency being noted upon the addition of sertraline and 10% glucose, respectively, compared with that in the control group without any additives. The induction of ROS generation, the activation of cellular antioxidant systems, increases in cell membrane permeability, and the promotion of adhesive pilus formation were factors potentially contributing to the increased transfer frequency. These findings indicate that conjugative transfer could be enhanced under certain circumstances in SGF at elevated pH levels, thereby facilitating ARG transmission in the gastrointestinal tract. IMPORTANCE The low pH of gastric acid kills unwanted microorganisms, in turn affecting their inhabitation in the intestine. Hence, studies on the factors that influence antibiotic resistance gene (ARG) propagation in the gastrointestinal tract and on the underlying mechanisms are limited. In this study, we constructed a conjugative transfer model in the presence of simulated gastric fluid (SGF) and found that SGF could promote the dissemination of ARGs under high-pH conditions. Furthermore, antidepressant consumption and certain dietary factors could negatively impact this situation. Transcriptomic analysis and a reactive oxygen species assay revealed the overproduction of reactive oxygen species as a potential mechanism by which SGF could promote conjugative transfer. This finding can help provide a comprehensive understanding of the bloom of antibiotic-resistant bacteria in the body and create awareness regarding the risk of ARG transmission due to certain diseases or an improper diet and the subsequent decrease in gastric acid levels.

Prevotella histicola suppresses ferroptosis to mitigate ethanol-induced gastric mucosal lesions in mice

BACKGROUND

Ethanol-induced gastric mucosal lesions (EGML) is one of the most common digestive disorders for which current therapies have limited outcomes in clinical practice. Prevotella histicola (P. histicola) has shown probiotic efficacy against arthritis, multiple sclerosis and oestrogen deficiency-induced depression in mice; however, its role in EGML remains unclear in spite of its extensive colonisation of the stomach. Ferroptosis, which is characterised by lipid peroxidation, may be involved in EGML. Herein, we aimed to investigate the effects and underlying mechanism of action of P. histicola on EGML in the ferroptosis-dependent pathway.

METHODS

P. histicola was intragastrically administered for a week, and deferoxamine (DFO), a ferroptosis inhibitor, was intraperitoneally injected prior to oral ethanol administration. The gastric mucosal lesions and ferroptosis were assessed via histopathological examinations, quantitative real-time PCR, Western blot, immunohistochemistry and immunofluorescence.

RESULTS

P. histicola was originally found to attenuate EGML by reducing histopathological changes and lipid reactive oxygen species (ROS) accumulation. The pro-ferroptotic genes of Transferrin Receptor (TFR1), Solute Carrier Family 39 Member 14 (SLC39A14), Haem Oxygenase-1 (HMOX-1), Acyl-CoA Synthetase Long-chain Family Member 4 (ACSL4), Cyclooxygenase 2 (COX-2) and mitochondrial Voltage-dependent Anion Channels (VDACs) were up-regulated; the anti-ferroptotic System Xc-/Glutathione Peroxidase 4 (GPX4) axis was inhibited after ethanol administration. However, the changes of histopathology and ferroptosis-related parameters induced by ethanol were reversed by DFO. Furthermore, P. histicola treatment significantly downregulated the expression of ACSL4, HMOX-1 and COX-2, as well as TFR1 and SLC39A14, on mRNA or the protein level, while activating the System Xc-/GPX4 axis.

CONCLUSIONS

We found that P. histicola reduces ferroptosis to attenuate EGML by inhibiting the ACSL4- and VDAC-dependent pro-ferroptotic pathways and activating the anti-ferroptotic System Xc-/GPX4 axis.

Differential roles of the fish chitinous membrane in gut barrier immunity and digestive compartments

The chitin-based peritrophic matrix (PM) is a structure critical for both gut immunity and digestion in invertebrates. PM was traditionally considered lost in all vertebrates, but a PM-like chitinous membrane (CM) has recently been discovered in fishes, which may increase the knowledge on vertebrate gut physiology and structural evolution. Here, we show that in zebrafish, the CM affects ingestion behavior, microbial homeostasis, epithelial renewal, digestion, growth, and longevity. Young mutant fish without CM appear healthy and are able to complete their life cycle normally, but with increasing age they develop gut inflammation, resulting in gut atrophy. Unlike mammals, zebrafish have no visible gel-forming mucin layers to protect their gut epithelia, but at least in young fish, the CM is not a prerequisite for the antibacterial gut immunity. These findings provide new insights into the role of the CM in fish prosperity and its eventual loss in tetrapods. These findings may also help to improve fish health and conservation, as well as to advance the understanding of vertebrate gut physiology and human intestinal diseases.

Homo medicus: The transition to meat eating increased pathogen pressure and the use of pharmacological plants in Homo

The human lineage transitioned to a more carnivorous niche 2.6 mya and evolved a large body size and slower life history, which likely increased zoonotic pathogen pressure. Evidence for this increase includes increased zoonotic infections in modern hunter-gatherers and bushmeat hunters, exceptionally low stomach pH compared to other primates, and divergence in immune-related genes. These all point to change, and probably intensification, in the infectious disease environment of Homo compared to earlier hominins and other apes. At the same time, the brain, an organ in which immune responses are constrained, began to triple in size. We propose that the combination of increased zoonotic pathogen pressure and the challenges of defending a large brain and body from pathogens in a long-lived mammal, selected for intensification of the plant-based self-medication strategies already in place in apes and other primates. In support, there is evidence of medicinal plant use by hominins in the middle Paleolithic, and all cultures today have sophisticated, plant-based medical systems, add spices to food, and regularly consume psychoactive plant substances that are harmful to helminths and other pathogens. We propose that the computational challenges of discovering effective plant-based treatments, the consequent ability to consume more energy-rich animal foods, and the reduced reliance on energetically-costly immune responses helped select for increased cognitive abilities and unique exchange relationships in Homo. In the story of human evolution, which has long emphasized hunting skills, medical skills had an equal role to play.

Global Patterns of Trends in Cholera Mortality

BACKGROUND

Cholera is a large public health issue, especially in countries with limited resources. The aim of the study was to determine trends in global cholera mortality from 1990-2019.

METHODS

This research is an observational, descriptive epidemiological study. The age-standardized rates (ASRs, per 100,000 population) of cholera mortality from 1990 to 2019 were evaluated through joinpoint regression analysis (by calculating Odds Ratio-OR, with corresponding 95% Confidence Interval-95% CI).

RESULTS

From 1990-2019 in the world, the number of deaths due to cholera in both sexes together increased, ranging from 83,045 in 1990 to 117,167 in 2019. During the observed period, there were about 3.0 million deaths due to cholera in the world. In both sexes together in 2019, the cholera mortality rate was the highest in Nigeria (ARS = 39.19) and Central African Republic (ARS = 38.80), followed by populations in Eritrea (ARS = 17.62) and Botswana (ARS = 13.77). Globally, cholera-related mortality significantly decreased in males (AAPC = -0.4%, 95% CI = -0.7 to -0.1), while a stable trend was noted in females (AAPC = -0.1%, 95% CI = -0.4 to 0.2) in the observed period. In the African Region, significantly increasing cholera-related mortality trends were observed both in males and females (AAPC = 1.3% and AAPC = 1.1%, respectively).

CONCLUSIONS

Cholera mortality showed a constantly increasing trend in the African Region over the last three decades. More efforts in cholera management are necessary for effective response to the growing mortality in developing countries.

Listeriosis Risk Model for Cancer Patients Who Consume Ready-to-Eat Salad

The foodborne pathogen Listeria monocytogenes generally infects immunocompromised individuals, such as cancer patients, more frequently and with higher morbidity and mortality than the general population. Because of the anticipated risk associated with L. monocytogenes and other pathogens in produce, immunocompromised individuals are often placed on neutropenic diets that exclude fresh produce, though these risks have not been quantified. Therefore, this study developed a data-driven risk model for listeriosis in cancer patients who consume ready-to-eat (RTE) salads, consisting of leafy greens, cucumbers, and tomatoes, as influenced by kitchen-scale treatments and storage practices. Monte Carlo simulations were used to model the risk of invasive listeriosis during one chemotherapy cycle. Refrigerating all salad components decreased median risk by approximately one-half log. For refrigerated salads with no treatment, the predicted median risk was ≤ 4.3 × 10^-08. When salad ingredients were surface blanched with greens rinsed, the predicted risk decreased to 5.4 × 10^-10. Predicted risk was lowest (1.4 × 10^-13) for a blanched "salad" consisting of solely cucumbers and tomatoes. Interestingly, rinsing, as recommended by FDA only decreased median risk by 1 log. A sensitivity analysis revealed that the highly variable dose-response parameter k strongly influenced risk, indicating that reducing uncertainty in this variable may improve model accuracy. Overall, this study demonstrates that kitchen-scale pathogen reduction approaches have high risk-reduction efficacy and could be considered as an alternative to diets that exclude produce when making risk management decisions.

HIV-Positive Patients on Antiretroviral Therapy Have an Altered Mucosal Intestinal but Not Oral Microbiome

This study characterized compositional and functional shifts in the intestinal and oral microbiome in HIV-positive patients on antiretroviral therapy compared to HIV-negative individuals. Seventy-nine specimens were collected from 5 HIV-positive and 12 control subjects from five locations (colon brush, colon wash, terminal ileum [TI] brush, TI wash, and saliva) during colonoscopy and at patient visits. Microbiome composition was characterized using 16S rRNA sequencing, and microbiome function was predicted using bioinformatics tools (PICRUSt and BugBase). Our analysis indicated that the β-diversity of all intestinal samples (colon brush, colon wash, TI brush, and TI wash) from patients with HIV was significantly different from patients without HIV. Specifically, bacteria from genera Prevotella, Fusobacterium, and Megasphaera were more abundant in samples from HIV-positive patients. On the other hand, bacteria from genera Ruminococcus, Blautia, and Clostridium were more abundant in samples from HIV-negative patients. Additionally, HIV-positive patients had higher abundances of biofilm-forming and pathogenic bacteria. Furthermore, pathways related to translation and nucleotide metabolism were elevated in HIV-positive patients, whereas pathways related to lipid and carbohydrate metabolism were positively correlated with samples from HIV-negative patients. Our analyses further showed variations in microbiome composition in HIV-positive and negative patients by sampling site. Samples from colon wash, colon brush, and TI wash were significant between groups, while samples from TI brush and saliva were not significant. Taken together, here, we report altered intestinal microbiome composition and predicted function in patients with HIV compared to uninfected patients, though we found no changes in the oral microbiome. IMPORTANCE Over 37 million people worldwide are living with HIV. Although the availability of antiretroviral therapy has significantly reduced the number of AIDS-related deaths, individuals living with HIV are at increased risk for opportunistic infections. We now know that HIV interacts with the trillions of bacteria, fungi, and viruses in the human body termed the microbiome. Only a limited number of previous studies have compared variations in the oral and gastrointestinal microbiome with HIV infection. Here, we detail how the oral and gastrointestinal microbiome changes with HIV infection, having used 5 different sampling sites to gain a more comprehensive view of these changes by location. Our results show site-specific changes in the intestinal microbiome associated with HIV infection. Additionally, we show that while there were significant changes in the intestinal microbiome, there were no significant changes in the oral microbiome.

ZLN005 improves the survival of polymicrobial sepsis by increasing the bacterial killing via inducing lysosomal acidification and biogenesis in phagocytes

Polymicrobial sepsis still has a high mortality rate despite the development of antimicrobial agents, elaborate strategies to protect major organs, and the investment of numerous medical resources. Mitochondrial dysfunction, which acts as the center of energy metabolism, is clearly the basis of pathogenesis. Drugs that act on PGC1α, the master regulator of mitochondrial biosynthesis, have shown useful effects in the treatment of sepsis; therefore, we investigated the efficacy of ZLN005, a PGC1α agonist, and found significant improvement in overall survival in an animal model. The mode of action of this effect was examined, and it was shown that the respiratory capacity of mitochondria was enhanced immediately after administration and that the function of TFEB, a transcriptional regulator that promotes lysosome biosynthesis and mutually enhances PGC1α, was enhanced, as was the physical contact between mitochondria and lysosomes. ZLN005 strongly supported immune defense in early sepsis by increasing lysosome volume and acidity and enhancing cargo degradation, resulting in a significant reduction in bacterial load. ZLN005 rapidly acted on two organelles, mitochondria and lysosomes, against sepsis and interactively linked the two to improve the pathogenesis. This is the first demonstration that acidification of lysosomes by a small molecule is a mechanism of action in the therapeutic strategy for sepsis, which will have a significant impact on future drug discovery.

Impact of oral microbiota on pathophysiology of GVHD

Allogeneic transplantation of hematopoietic cells is the only curative therapy for several hematopoietic disease in which patients receive cytotoxic conditioning regimens followed by infusion of hematopoietic stem cells. Although the outcomes have improved over the past decades, graft-versus-host-disease (GVHD), the most common life-threatening complication, remains a major cause of non-relapse morbidity and mortality. Pathophysiology of acute GVHD characterized by host antigen-presenting cells after tissue damage and donor T-cells is well studied, and additionally the importance of recipient microbiota in the intestine is elucidated in the GVHD setting. Oral microbiota is the second most abundant bacterial flora in the body after the intestinal tract, and it is related to chronic inflammation and carcinogenesis. Recently, composition of the oral microbiome in GVHD related to transplantation has been characterized and several common patterns, dysbiosis and enrichment of the specific bacterial groups, have been reported. This review focuses on the role of the oral microbiota in the context of GVHD.

The possible association of proton pump inhibitor use with acute cholangitis in patients with choledocholithiasis: a multi-center study

BACKGROUND

Gallstone disease is common worldwide and can lead to severe complications, including cholangitis; thus, it is important to identify modifiable risk factors for cholangitis. Proton pump inhibitors (PPIs) are commonly prescribed to treat gastroenterological disorders. We aimed to explore whether PPI use is associated with an increased risk of acute cholangitis in patients with gallstone disease.

METHODS

This retrospective multicenter study included all patients arriving to the hospital over a 10-year period with various presentations of choledocholithiasis. We compared active PPI use in two groups: those with cholangitis (group A) vs. without cholangitis (group B).

RESULTS

Overall, 811 patients were included, 161 in group A and 650 in group B. The average age ± standard deviation (SD) in groups A and B was 74.5 ± 20.6 vs. 61.6 ± 20.9 years, respectively. PPI use in group A was higher vs. group B (42.9% vs. 29.1%, p = 0.001). On univariate analysis, male gender (OR 1.47, 95% confidence interval (CI) 1.04-2.08), age (OR 1.04, 95% CI 1.03-1.05), ischemic heart disease (IHD) (OR 1.68, 95% CI 1.07-2.64), hyperlipidemia (OR 1.59, 95% CI 1.11-2.29), hypertension (OR 1.81, 95% CI 1.28-2.57) and PPI use (OR 1.83, 95% CI 1.28-2.61), all were associated with acute cholangitis. On multivariate analysis, only PPI use kept its association after adjustment for age (OR 1.64, 95% CI 1.2-3.7).

CONCLUSIONS

Active PPI use was associated with a higher rate of cholangitis among patients with choledocholithiasis. We advocate considering this risk before prescribing PPIs to patients with gallstones.

TRIAL REGISTRATION NUMBER

NHR-0263-20 received on 14/01/2021 date 'retrospectively registered'.

Alterations of oral microbiota and impact on the gut microbiome in type 1 diabetes mellitus revealed by integrated multi-omic analyses

BACKGROUND

Alterations to the gut microbiome have been linked to multiple chronic diseases. However, the drivers of such changes remain largely unknown. The oral cavity acts as a major route of exposure to exogenous factors including pathogens, and processes therein may affect the communities in the subsequent compartments of the gastrointestinal tract. Here, we perform strain-resolved, integrated meta-genomic, transcriptomic, and proteomic analyses of paired saliva and stool samples collected from 35 individuals from eight families with multiple cases of type 1 diabetes mellitus (T1DM).

RESULTS

We identified distinct oral microbiota mostly reflecting competition between streptococcal species. More specifically, we found a decreased abundance of the commensal Streptococcus salivarius in the oral cavity of T1DM individuals, which is linked to its apparent competition with the pathobiont Streptococcus mutans. The decrease in S. salivarius in the oral cavity was also associated with its decrease in the gut as well as higher abundances in facultative anaerobes including Enterobacteria. In addition, we found evidence of gut inflammation in T1DM as reflected in the expression profiles of the Enterobacteria as well as in the human gut proteome. Finally, we were able to follow transmitted strain-variants from the oral cavity to the gut at the individual omic levels, highlighting not only the transfer, but also the activity of the transmitted taxa along the gastrointestinal tract.

CONCLUSIONS

Alterations of the oral microbiome in the context of T1DM impact the microbial communities in the lower gut, in particular through the reduction of "mouth-to-gut" transfer of Streptococcus salivarius. Our results indicate that the observed oral-cavity-driven gut microbiome changes may contribute towards the inflammatory processes involved in T1DM. Through the integration of multi-omic analyses, we resolve strain-variant "mouth-to-gut" transfer in a disease context. Video Abstract.

Effects of different grains on bacterial diversity and enzyme activity associated with digestion of starch in the foal stomach

Background

Compared with the stomach of ruminant cattle, the stomach of horse is small and mainly for chemical digestion, but the microorganisms in the stomach play an important role in maintaining the homeostasis of the internal environment. Due to the complexity of the microbes in the stomach, little is known about the diversity and structure of bacteria in the equine stomach. Grains are the main energy source for plant-eating livestock and energy is derived through enzymatic hydrolysis of grains into glucose or their microbial fermentation into Volatile fatty acids (VFA). However, the mechanism through which these ingested grains are chemically digested as well as the effect of these grains on the stomach remains elusive. This study explored the effects of feeding different grains (corn, oats, and barley) on bacterial diversity, structure, and composition in the foal’s stomach content. Furthermore, the effects of different grains on the vitality of starch digestion-related stomach enzymes were investigated.

Results

No significant differences were observed (P > 0.05) in the bacterial rarefaction curves of Operational Taxonomic Units (OTUs) and diversity of the stomach microbiota in all foals. This study also revealed the statistical differences for Firmicutes, Cyanobacteria, Actinobacteria, Fibrobacteres, Lactobacillaceae, Streptococcaceae, Unidentified_Clostridiales, Prevotellaceae, Lactobacillus, Streptococcus, Unidentified_Cyanobacteria, Unidentified_Clostridiales, Lactococcus, Sphingomonas, Lactobacillus_hayakitensis, Lactobacillus_equigenerosi, and Clostridium_perfringens. The linear discriminant analysis effect size analysis revealed 9 bacteria at each classification level. The functional analysis of species information by using FAPROTAX software was able to predict 35 functions, and the top 5 functions were chemoheterotrophy, fermentation, animal_parasites_or_symbionts, nitrate_reduction, and aerobic_chemoheterotrophy. The study also revealed statistical differences for pH, glucose concentration, β-amylase, maltase, and amylase.

Conclusions

The different grains had no significant effect on the microbial diversity of the stomach content of the foal. However, the relative bacterial abundances differed significantly in response to different diets. Particularly, oats fed to the foals significantly increased the relative abundance of Firmicutes, Lactobacillaceae, Lactobacillus, and Lactobacillus_hayakitensis. The grain had no significant effect on the pH of the stomach content, glucose concentration, and enzyme viability in the foal.

Bacterial battle against acidity

The Earth is home to environments characterized by low pH, including the gastrointestinal tract of vertebrates and large areas of acidic soil. Most bacteria are neutralophiles, but can survive fluctuations in pH. Herein, we review how Escherichia, Salmonella, Helicobacter, Brucella, and other acid-resistant Gram-negative bacteria adapt to acidic environments. We discuss the constitutive and inducible defense mechanisms that promote survival, including proton-consuming or ammonia-producing processes, cellular remodeling affecting membranes and chaperones, and chemotaxis. We provide insights into how Gram-negative bacteria sense environmental acidity using membrane-integrated and cytosolic pH sensors. Finally, we address in more detail the powerful proton-consuming decarboxylase systems by examining the phylogeny of their regulatory components and their collective functionality in a population.

Bacterial Involvement in Progression and Metastasis of Adenocarcinoma of the Stomach

Simple Summary

Infectious bacteria influence primary gastric carcinogenesis, organotropism, and metastatic progression by altering the microenvironment at the primary and secondary tumors. Key species include Helicobacter pylori (H. pylori) and Mycoplasma hyorhinis (M. hyorhinis). Inflammation caused by H. pylori virulence factors, such as CagA, VacA, and oipA, disrupt epithelial integrity, which allows the primary tumor to progress through the metastatic process. Evidence supports the activation of aquaporin-5 by CagA-positive H. pylori infection, promoting epithelial–mesenchymal transition via the extracellular signal-regulated kinase/mitogen-activated protein kinase (MEK/ERK) pathway, thus laying the foundation for metastatic disease. M. hyorhinis has also been implicated in gastric neoplasia via β-catenin stabilization and subsequent activation of the WNT-signaling pathway, promoting gastric cancer cell motility and inciting cancer progression.

Abstract

Gastric cancer metastasis is a process in which the tumor microenvironment may carry significant influence. Helicobacter pylori (H. pylori) infection is well-established as a contributor to gastric carcinoma. However, the role that these bacteria and others may play in gastric carcinoma metastasis is a current focus of study. A review of the literature was conducted to elucidate the process by which gastric adenocarcinoma metastasizes, including its ability to utilize both the lymphatic system and the venous system to disseminate. Studies that investigate the tumor microenvironment at both the primary and secondary sites were assessed in detail. H. pylori and Mycoplasma hyorhinis (M. hyorhinis) were found to be important drivers of the pathogenesis of gastric adenocarcinoma by modifying various steps in cell metastasis, including epithelial–mesenchymal transition, cell migration, and cell invasion. H. pylori is also a known driver of MALT lymphoma, which is often reversible simply with the eradication of infection. M. hyorhinis has been implicated in gastric neoplasia via β-catenin stabilization and subsequent activation of the WNT-signaling pathway, promoting gastric cancer cell motility and inciting cancer progression. Fusobacterium nucleatum (F. nucleatum) and its association with worse prognosis in diffuse-type gastric adenocarcinoma are also reviewed. Recognition of the roles that bacteria play within the metastatic cascade is vital in gastrointestinal adenocarcinoma treatment and potential reoccurrence. Further investigation is needed to establish potential treatment for metastatic gastric carcinoma by targeting the tumor microenvironment.

Gut Microbiota in Nutrition and Health with a Special Focus on Specific Bacterial Clusters

Health is influenced by how the gut microbiome develops as a result of external and internal factors, such as nutrition, the environment, medication use, age, sex, and genetics. Alpha and beta diversity metrics and (enterotype) clustering methods are commonly employed to perform population studies and to analyse the effects of various treatments, yet, with the continuous development of (new) sequencing technologies, and as various omics fields as a result become more accessible for investigation, increasingly sophisticated methodologies are needed and indeed being developed in order to disentangle the complex ways in which the gut microbiome and health are intertwined. Diseases of affluence, such as type 2 diabetes (T2D) and cardiovascular diseases (CVD), are commonly linked to species associated with the Bacteroides enterotype(s) and a decline of various (beneficial) complex microbial trophic networks, which are in turn linked to the aforementioned factors. In this review, we (1) explore the effects that some of the most common internal and external factors have on the gut microbiome composition and how these in turn relate to T2D and CVD, and (2) discuss research opportunities enabled by and the limitations of some of the latest technical developments in the microbiome sector, including the use of artificial intelligence (AI), strain tracking, and peak to trough ratios.

The digestive systems of carnivorous plants

To survive in the nutrient-poor habitats, carnivorous plants capture small organisms comprising complex substances not suitable for immediate reuse. The traps of carnivorous plants, which are analogous to the digestive systems of animals, are equipped with mechanisms for the breakdown and absorption of nutrients. Such capabilities have been acquired convergently over the past tens of millions of years in multiple angiosperm lineages by modifying plant-specific organs including leaves. The epidermis of carnivorous trap leaves bears groups of specialized cells called glands, which acquire substances from their prey via digestion and absorption. The digestive glands of carnivorous plants secrete mucilage, pitcher fluids, acids, and proteins, including digestive enzymes. The same (or morphologically distinct) glands then absorb the released compounds via various membrane transport proteins or endocytosis. Thus, these glands function in a manner similar to animal cells that are physiologically important in the digestive system, such as the parietal cells of the stomach and intestinal epithelial cells. Yet, carnivorous plants are equipped with strategies that deal with or incorporate plant-specific features, such as cell walls, epidermal cuticles, and phytohormones. In this review, we provide a systematic perspective on the digestive and absorptive capacity of convergently evolved carnivorous plants, with an emphasis on the forms and functions of glands.

Proton Pump Inhibitors in the COVID-19 Pandemic

The safety of proton pump inhibitors (PPIs) use in coronavirus infection (COVID-19) is not well understood. PPIs are potent suppressors of gastric secretion and become one of the ten most widely used drugs in the world. They are expected to influence virus susceptibility, severity, and outcomes in patients diagnosed with COVID-19. This concern is based on their mechanism of action — suppression of gastric acidity, which is considered the first line of defense against infections. Taken together, the results of most studies and meta-analyses support that PPIs use has been associated with increased risk of COVID-19 and severe outcomes. However, taking into account all potential risk factors for disease severity seems impossible in the real world in the context of COVID-19, so conclusions about causal relationships between PPI use and COVID-19 should be treated with great caution. An additional interesting point about the use of PPIs in the pandemic is that it reduced absorption of certain vitamins. On the other hand, several studies have appeared in the literature regarding the protective therapeutic effects of PPIs. There is growing evidence of an immunomodulatory and antifibrotic role of PPIs that could be used in the treatment of COVID-19. In addition, their ability to alkalize the contents of endosomes and lysosomes serves as an obstacle to the penetration of the virus into host cells. This review analyzes the possible effects of PPIs in patients with COVID-19.

Untangling the oral-gut axis in the pathogenesis of intestinal inflammation

An increasing body of literature reveals that host-microbe networks are well-coordinated and impact human health and disease. Recently, it has become evident that an abnormal alteration in bacterial configuration in the oral cavity, namely oral dysbiosis, caused by periodontal inflammation, is associated with various distant inflammatory diseases, including inflammatory bowel disease. However, the extent to which the relationships between oral and distant disorders are merely an association or are causally triggered by oral microorganisms remains debated. In this mini-review, we highlight mechanisms in inter-related organ system diseases , particularly the one between oral and gut inflammation. Further, we discuss clinical perspectives and propose a novel concept of a multi-hit hypothesis in the pathogenesis of gut inflammation, based on our updated knowledge of shared microbiological and immunological pathways between the oral and gut mucosae.

Impact of proton pump inhibitors on the in-hospital outcome of COVID-19 patients: a retrospective study

BACKGROUND

Coronavirus disease 2019 (COVID-19) has triggered a global public health crisis. Proton pump inhibitors (PPIs) are one of the most commonly prescribed drugs. However, the effect of PPIs on the clinical outcomes of COVID-19 patients remains unclear.

METHODS

All COVID-19 patients admitted to the Wuhan Huoshenshan Hospital from February 2020 to April 2020 were retrospectively collected. Patients were divided into PPIs and non-PPIs groups. Logistic regression analyses were performed to explore the effects of PPIs on the outcomes of COVID-19 patients, including transfer to intensive care unit, mechanical ventilation, and death. Subgroup analyses were performed according to the presence of upper gastrointestinal symptoms potentially associated with acid and the routes, types, median total dosage, and duration of PPIs. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Of the 3024 COVID-19 patients included, 694 and 2330 were in PPIs and non-PPIs groups, respectively. Univariate logistic regression analysis showed that PPIs significantly increased the risk of reaching the composite endpoint in COVID-19 patients (OR = 10.23, 95% CI = 6.90-15.16, p < 0.001). After adjusting for age, sex, comorbidities, other medications, and severe/critical COVID-19, PPIs were independently associated with an increased risk of reaching the composite endpoint (OR = 7.00, 95% CI = 4.57-10.71, p < 0.001). This association remained significant in patients with upper gastrointestinal symptoms and those who received an intravenous omeprazole alone, but not those who received oral lansoprazole or rabeprazole alone. It was not influenced by dosage or duration of PPIs.

CONCLUSION

The use of intravenous PPIs alone during hospitalization may be associated with worse clinical outcome in COVID-19 patients.

Periodontal connection with intestinal inflammation: Microbiological and immunological mechanisms

Humans have coevolved with the trillions of resident microbes that populate every nook and cranny of the body. At each site, the resident microbiota creates a unique ecosystem specialized to its environment, benefiting the development and maintenance of human physiology through harmonious symbiotic relationships with the host. However, when the resident microbiota is perturbed, significant complications may arise with disastrous consequences that affect the local and distant ecosystems. In this context, periodontal disease results in inflammation beyond the oral cavity, such as in the gastrointestinal tract. Accumulating evidence indicates that potentially harmful oral resident bacteria (referred to as pathobionts) and pathogenic immune cells in the oral mucosa can migrate to the lower gastrointestinal tract and contribute to intestinal inflammation. We will review the most recent advances concerning the periodontal connection with intestinal inflammation from microbiological and immunological perspectives. Potential therapeutic approaches that target the connection between the mouth and the gut to treat gastrointestinal diseases, such as inflammatory bowel disease, will be examined. Deciphering the complex interplay between microbes and immunity along the mouth-gut axis will provide a better understanding of the pathogenesis of both oral and gut pathologies and present therapeutic opportunities.

Novel Potassium-Competitive Acid Blocker, Tegoprazan, Protects Against Colitis by Improving Gut Barrier Function

Inflammatory bowel disease (IBD) is a chronic immune-mediated disorder characterized by prolonged inflammation of the gastrointestinal tract. IBD can result from gut barrier dysfunction, altered gut microbiota, and abnormal intestinal immunity induced by environmental factors in genetically susceptible individuals. Proton pump inhibitors (PPIs) such as rabeprazole are frequently employed for gastric acid inhibition. However, long-term PPI administration can alter the intestinal microbiome composition, possibly worsening IBD severity. The present study revealed that tegoprazan, a potassium-competitive acid blocker, significantly improved colitis in mice and enhanced the intestinal epithelial barrier function. Tegoprazan alleviated gut microbiota dysbiosis and enhanced the growth of Bacteroides vulgatus. In turn, B. vulgatus alleviated intestinal inflammation by inhibiting epithelial adhesion of pathogenic bacteria. Unlike rabeprazole, tegoprazan did not induce gut dysbiosis. Our findings provide novel insights into the potential role of tegoprazan as an intestinal protectant for IBD and as a therapeutic agent for gastric acid-related diseases.

Oral and Stool Microbiome Coalescence and Its Association With Antibiotic Exposure in Acute Leukemia Patients

Failure to maintain segregation of oral and gut microbial communities has been linked to several diseases. We sought to characterize oral-fecal microbiome community coalescence, ectopic extension of oral bacteria, clinical variables contributing to this phenomenon, and associated infectious consequences by analyzing the 16S rRNA V4 sequences of longitudinal fecal (n=551) and oral (n=737) samples from 97 patients with acute myeloid leukemia (AML) receiving induction chemotherapy (IC). Clustering observed in permutation based multivariate analysis of variance (PERMANOVA) of Bray-Curtis dissimilarity and PCoA plot of UniFrac distances between intra-patient longitudinal oral-stool sample pairs suggested potential oral-stool microbial community coalescence. Bray-Curtis dissimilarities and UniFrac distances were used to create an objective definition of microbial community coalescence. We determined that only 23 of the 92 patients exhibited oral-stool community coalescence. This was validated through a linear mixed model which determined that patients who experienced coalescence had an increased proportion of shared to unique OTUs between their oral-stool sample pairs over time compared to non-coalesced patients. Evaluation of longitudinal microbial characteristics revealed that patients who experienced coalescence had increased stool abundance of Streptococcus and Stenotrophomonas compared to non-coalesced patients. When treated as a time-varying covariate, each additional day of linezolid (HR 1.15, 95% CI 1.06 – 1.24, P <0.001), meropenem (HR 1.13, 95% CI 1.05 – 1.21, P = 0.001), metronidazole (HR 1.13, 95% CI 1.05 – 1.21, P = 0.001), and cefepime (HR 1.10, 95% CI 1.01 – 1.18, P = 0.021) increased the hazard of oral-stool microbial community coalescence. Levofloxacin receipt was associated with a lower risk of microbiome community coalescence (HR 0.75, 95% CI 0.61 – 0.93, P = 0.009). By the time of neutrophil recovery, the relative abundance of Bacteroidia (P<0.001), Fusobacteria (P=0.012), and Clostridia (P=0.013) in the stool were significantly lower in patients with oral-gut community coalescence. Exhibiting oral-stool community coalescence was associated with the occurrence of infections prior to neutrophil recovery (P=0.002), as well as infections during the 90 days post neutrophil recovery (P=0.027). This work elucidates specific antimicrobial effects on microbial ecology and furthers the understanding of oral/intestinal microbial biogeography and its implications for adverse clinical outcomes.