Causal effect of gut microbiota on Gastroduodenal ulcer: a two-sample Mendelian randomization study

Drinking Water Temperature Impacts the Pathogenesis of DSS-Induced Ulcerative Colitis by Regulating Intestinal Barrier Function and Remodeling the Gut Microbiota Composition

Environmental factors, including poor dietary habits and unhealthy drinking patterns, contribute to ulcerative colitis (UC). While the relationship between diet-related malnutrition and UC has been extensively explored, the impact of drinking water temperature remains largely overlooked, prompting us to investigate its influence on UC pathogenesis and explore the underlying mechanisms. In the present study, we observed that, unlike external thermal and cold therapy, varying drinking water temperatures transiently altered the internal body temperature of the digestive tract. Specifically, chronic drinking of 0°C water had significant anti-inflammatory effects and preserved the integrity of the mucosal barrier in a colitis mouse model. Mechanistically, this temperature spectrum changed the composition of the gut microbiota from inflammation-prone (25°C drinking water) to a resting pattern similar to that of the negative control. Specifically, the abundances of Blautia and Parasutterella, two beneficial genera, were strongly increased in response to 0°C water, accompanied by elevated levels of short-chain fatty acids. In contrast, drinking 40°C water had opposite effects on all the examined parameters and generally aggravated the development of colitis. This study is the first to demonstrate how modifying the temperature of habitual drinking water can modulate colitis progression, providing a novel and noninvasive approach to UC management. Specifically, chronic consumption of 0°C water alleviated the severity of colitis, whereas 40°C water aggravated the disease. Therefore, by focusing on commonly consumed drinking water temperatures, our findings suggest that this simple intervention could be a safe, convenient, and effective therapeutic strategy.

Health effects of astaxanthin in the intestinal tract of yellow-feathered broilers

Astaxanthin (AST), a keto carotenoid, is widely recognized for its antioxidant, anti-inflammatory, and apoptosis-regulating properties, but its effects on intestinal health have not been elucidated. Therefore, this experiment aimed to investigate the effects of astaxanthin on intestinal morphology, barrier function, mucosal immunity, and cecal flora in yellow-feathered broilers, and to explore the potential mechanisms. A total of 288 male yellow-feathered broilers (1-day-old) were randomly allocated to four groups with six replicates of 12 birds each. The control group (CON) was fed a basal diet, the test groups were fed a basal diet added with 20 mg/kg, 40 mg/kg, and 80mg/kg of astaxanthin (AST20, AST40, and AST80), respectively. The results showed that compared with the CON group, the villus height and the villus-to-crypt ratio of broiler jejunum in the astaxanthin-added group increased, while the crypt depth decreased (P < 0.05). In addition, IL-1β content and gene expression in broiler jejunal mucosa decreased, IL-6 gene expression decreased, and IL-4 content and gene expression increased (P < 0.05). The tight junction protein ZO-1 expression level in the jejunum mucosa of broilers was up-regulated, and the content of serum D-lactic acid was decreased (P < 0.05). Besides, the α-diversity and β-diversity analyses showed that astaxanthin regulated both the diversity and the structure of the intestinal flora of broilers. After multiple comparative analyses, the relative abundance of norank_f__Eubacterium_coprostanoligenes_group, Lachnospiraceae NC2004_group, and unclassified_p_Firmicutes increased in the AST20 group compared to the CON group, while that of Ruminococcus_torques_group in the AST80 group decreased (P < 0.05). Therefore, AST can regulate the immune function of broiler intestinal mucosa, improve intestinal morphology and structure, and then influence intestinal permeability. It also has a considerable regulatory effect on the diversity and structure of broiler intestinal flora and plays a multifaceted role in maintaining broiler intestinal health.

Structural characteristics of a purified Evodiae fructus polysaccharide and its gastroprotection and relevant mechanism against alcohol-induced gastric lesions in rats

Evodiae fructus polysaccharide (EFP) has been previously shown to protect against alcohol-induced gastric lesions. However, which and how active fractions in EFP exert gastroprotection remains unclear. This study aimed to characterize the structure of the purified fraction (EFP-2-1) of EFP, and investigate its gastroprotection and underlying mechanisms. EFP-2-1 was obtained through column chromatography, and was characterized using instrumental analytical techniques. Gastroprotective effect of EFP-2-1 was evaluated using alcohol-induced gastric lesions in rats, and its mechanism was explored through proteomics, metabolomics and diversity sequencing. Results showed that EFP-2-1 had a molecular weight of 7.3 kDa, and consisted mainly of rhamnose, galacturonic acid, galactose and arabinose. Its backbone contained HG and RG-I domains, and branched with →5)-α-l-Araf-(1→, α-l-Araf-(1→ and →4)-β-d-Galp-(1→ residues. EFP-2-1 reduced gastric lesions and the levels of MDA, TNF-α and IL-6, activated PPARγ, primarily altered protein digestion and absorption and bile secretion metabolic pathways, regulated gut microbiota like Faecalibaculum and Lachnoclostridium, and increased short-chain fatty acids production. Correlations were observed among the gut microbiota, metabolites and biochemical indexes influenced by EFP-2-1. These findings suggest that EFP-2-1 is an active fraction of EFP for protecting against alcohol-induced gastric lesions, which may be linked to PPARγ activation, gut microbiota and serum metabolism.

Resveratrol attenuates non-steroidal anti-inflammatory drug-induced intestinal injury in rats in a high-altitude hypoxic environment by modulating the TLR4/NFκB/IκB pathway and gut microbiota composition

INTRODUCTION

Non-steroidal anti-inflammatory drugs (NSAIDs) are currently the most widely used anti-inflammatory medications, but their long-term use can cause damage to the gastrointestinal tract(GIT). One of the risk factors for GIT injury is exposure to a high-altitude hypoxic environment, which can lead to damage to the intestinal mucosal barrier. Taking NSAIDs in a high-altitude hypoxic environment can exacerbate GIT injury and impact gut microbiota. The aim of this study is to investigate the mechanisms by which resveratrol (RSV) intervention alleviates NSAID-induced intestinal injury in a high-altitude hypoxic environment, as well as its role in regulating gut microbiota.

METHODS

Aspirin was administered orally to rats to construct a rat model of intestinal injury induced by NSAIDs. Following the induction of intestinal injury, rats were administered RSV by gavage, and the expression levels of TLR4, NF-κB,IκB as well as Zonula Occludens-1 (ZO-1) and Occludin proteins in the different treatment groups were assessed via Western blot. Furthermore, the expression of the inflammatory factors IL-10, IL-1β, and TNF-α was evaluated using Elisa.16sRNA sequencing was employed to investigate alterations in the gut microbiota.

RESULTS

The HCk group showed elevated expression of TLR4/NF-κB/IκB pathway proteins, increased expression of pro-inflammatory factors IL-1β and TNF-α, decreased expression of the anti-inflammatory factor IL-10, and expression of intestinal mucosal barrier proteins ZO-1 and Occludin. The administration of NSAIDs drugs in the plateau hypoxic environment exacerbates intestinal inflammation and damage to the intestinal mucosal barrier. After treatment with RSV intervention, the expression of TLR4/NF-κB/IκB signaling pathway proteins would be reduced, thereby lowering the expression of inflammatory factors in the HAsp group. The results of HE staining directly show the damage to the intestines and the repair of intestinal mucosa after RSV intervention. 16sRNA sequencing results show significant differences (P<0.05) in Ruminococcus, Facklamia, Parasutterella, Jeotgalicoccus, Coprococcus, and Psychrobacter between the HCk group and the Ck group. Compared to the HCk group, the HAsp group shows significant differences (P<0.05) in Facklamia, Jeotgalicoccus, Roseburia, Psychrobacter, and Alloprevotella. After RSV intervention, Clostridium_sensu_stricto bacteria significantly increase compared to the HAsp group.

CONCLUSION

Resveratrol can attenuate intestinal damage caused by the administration of NSAIDs at high altitude in hypoxic environments by modulating the TLR4/NF-κB/IκB signaling pathway and gut microbiota composition.

The causal relationship between gut microbiota and diabetic neuropathy: a bi-directional two-sample Mendelian randomization study

Background

Many studies suggest a strong correlation between gut microbiota (GM) and diabetic neuropathy (DN). However, the precise causal relationship between GM and DN has yet to be fully elucidated. Hence, a bi-directional Mendelian randomization (MR) analysis was used to examine the association between GM and DN.

Methods

Widely known genome-wide association study (GWAS) of GM was collected from the MiBio Gen project. Summary-level datasets for DN were taken from the FinnGen project. Inverse variance weighted approach was used for evaluating the causal relationship between GM and DN. Subsequently, pleiotropy and heterogeneity tests were performed to verify the reliability of the data. Furthermore, a bidirectional two-sample MR analysis was done to investigate the directionality of the causal relationships. Gene Ontology analysis was conducted to identify the associations that could indicate biological functions.

Results

We identified potential causal associations between GM and DN (p< 0.05 in all three MR methods). Among them, we found increased levels of Christensenellaceae R-7 (Odds ratio, OR= 1.52; 95% confidence interval, CI = 1.03-2.23; p = 0.03), Ruminococcaceae UCG013 (OR =1.35; 95% CI = 1.00-1.85; p = 0.04), and Eggerthella groups (OR = 1.27; 95% CI = 1.05-1.55; p = 0.01), which may be associated with a higher risk of DN, while increased levels of Peptococcaceae (OR = 0.69; 95% CI = 0.54-0.90; p< 0.01) and Eubacterium coprostanoligenes groups (OR = 0.68; 95% CI = 0.49-0.93; p = 0.01) could be associated with a lower risk. Gene Ontology pathway analysis revealed enrichment of genes regulated by the associated single-nucleotide polymorphisms (SNPs) in the apical plasma membrane, glycosyltransferase activity, hexosyltransferase activity and membrane raft. Reverse MR analyses indicated that DN was associated with five microbial taxa in all three MR methods.

Conclusion

The results of our study validate the possible causative relationship between GM and DN. This discovery gives new perspectives into the mechanism on how GM influences DN, and establishes a theoretical foundation for future investigations into targeted preventive measures.

Novel carbonic anhydrase inhibitors for the treatment of Helicobacter pylori infection

INTRODUCTION

Helicobacter pylori, the causative agent of peptic ulcer, gastritis, and gastric cancer encodes two carbonic anhydrases (CA, EC 4.2.1.1) belonging to the α- and β-class (HpCAα/β), which have been validated as antibacterial drug targets. Acetazolamide and ethoxzolamide were also clinically used for the management of peptic ulcer.

AREAS COVERED

Sulfonamides were the most investigated HpCAα/β compounds, with several low nanomolar inhibitors identified, some of which also crystallized as adducts with HpCAα, allowing for the rationalization of the structure-activity relationship. Few data are available for other classes of inhibitors, such as phenols, sulfamides, sulfamates, dithiocarbamates, arylboronic acids, some of which showed effective in vitro inhibition and for phenols, also inhibition of planktonic growth, biofilm formation, and outer membrane vesicles spawning.

EXPERT OPINION

Several recent drug design studies reported selenazoles incorporating seleno/telluro-ethers attached to benzenesulfonamides, hybrids incorporating the EGFR inhibitor erlotinib and benzenesulfonamides, showing KIs < 100 nM against HpCAα and MICs in the range of 8-16 µg/mL for the most active derivatives. Few drug design studies for non-sulfonamide inhibitors were performed to date, although inhibition of these enzymes may help the fight of multidrug resistance to classical antibiotics which emerged in the last decades also for this bacterium.

Exposure to Microcystin-LR Promotes Colorectal Cancer Progression by Altering Gut Microbiota and Associated Metabolites in APCmin/+ Mice

Microcystins (MCs), toxins generated by cyanobacteria, feature microcystin-LR (MC-LR) as one of the most prevalent and toxic variants in aquatic environments. MC-LR not only causes environmental problems but also presents a substantial risk to human health. This study aimed to investigate the impact of MC-LR on APCmin/+ mice, considered as an ideal animal model for intestinal tumors. We administered 40 µg/kg MC-LR to mice by gavage for 8 weeks, followed by histopathological examination, microbial diversity and metabolomics analysis. The mice exposed to MC-LR exhibited a significant promotion in colorectal cancer progression and impaired intestinal barrier function in the APCmin/+ mice compared with the control. Gut microbial dysbiosis was observed in the MC-LR-exposed mice, manifesting a notable alteration in the structure of the gut microbiota. This included the enrichment of Marvinbryantia, Gordonibacter and Family_XIII_AD3011_group and reductions in Faecalibaculum and Lachnoclostridium. Metabolomics analysis revealed increased bile acid (BA) metabolites in the intestinal contents of the mice exposed to MC-LR, particularly taurocholic acid (TCA), alpha-muricholic acid (α-MCA), 3-dehydrocholic acid (3-DHCA), 7-ketodeoxycholic acid (7-KDCA) and 12-ketodeoxycholic acid (12-KDCA). Moreover, we found that Marvinbryantia and Family_XIII_AD3011_group showed the strongest positive correlation with taurocholic acid (TCA) in the mice exposed to MC-LR. These findings provide new insights into the roles and mechanisms of MC-LR in susceptible populations, providing a basis for guiding values of MC-LR in drinking water.