Search Results (928)

Establishing the relative stability of the gastrointestinal microbiome after birth is a long and complex process, and it occurs under various influences. The human gut microbiome plays a crucial role in influencing an individual’s health and well-being across all stages of life. Breastfeeding, the introduction of solid food at a certain stage after birth, and the type of food largely determine the composition of the developing microbiome. The influence of probiotics on the early development of the microbiome is gaining increasing interest. The method of in vitro co-cultivation with probiotic strains provides a clearer picture of the influence of these microorganisms on the community and the functional changes that the infant’s microbiome undergoes. We used fecal samples to study this influence by conducting metagenomic sequencing to determine the composition of the microbiome and a series of cultivations to determine the absorption of various fibers and prebiotic sugars from breast milk. We found statistically significant differences in the absorption of prebiotic sugars isolated from breast milk, as well as better absorption of several substrates in the presence of a probiotic strain. Full article

Background: The pathogenesis of various colon-related pathologies, including irritable bowel syndrome, uncomplicated diverticulitis, and tubular adenoma, remains unknown, primarily due to their multifactorial nature. These gastrointestinal diseases are increasing in prevalence in Western countries and are common conditions worldwide. Objective: To identify intestinal microbiota signs and their associations with the development of colonic pathologies, such as irritable bowel syndrome, uncomplicated diverticulitis, and tubular adenoma. Materials and Methods: An observational, prospective, cross-sectional study was conducted to compare the microbiome among three conditions via 16S rRNA sequencing of biopsy samples obtained via colonoscopy. Results: The microbiome of individuals with tubular adenoma was less diverse than that of patients with diverticulitis and irritable bowel syndrome, with a lower abundance of commensal bacterial genera, such as Catenibacterium, Bifidobacterium, and Faecalibacterium, and an increase in several genera with known pathogenic roles, including Escherichia–Shigella, Fusobacteria, Prevotella, and Haemophilus. No significant association was found between the type of pathology and the total pathogenic or commensal disease score; however, a ratio of 2.54 to pathogenic/commensal was observed in the IBS patient group. In contrast, in the diverticulitis and adenoma patient groups, this ratio was 8. Conclusions: These results provide evidence supporting the proposal that alterations in the colonic microbiome could be involved in various colonic pathogeneses and that an imbalance between commensal and pathogenic populations could be directly related to pathogenesis in the microsystem. It is important to highlight the need for future studies. Full article

Functional bowel disorders (FBDs) are chronic gastrointestinal conditions characterized by recurrent symptoms associated with gut microbiota dysbiosis. Although accumulating evidence suggests that probiotics can improve symptoms in patients with FBD, the underlying mechanisms remain to be fully elucidated. In this randomized, double-blind, placebo-controlled clinical trial, 38 adults meeting the Rome IV diagnostic criteria of functional constipation (FC) and functional diarrhea (FD) received either a multi-strain probiotic complex or placebo for 8 weeks. Clinical outcomes were evaluated using the Irritable Bowel Syndrome Severity Scoring System (IBS-SSS), bowel habits questionnaire, and IBS Quality of Life (IBS-QoL) instrument. Fecal samples were collected at baseline and at week 8 for gut microbiota profiling via 16S rRNA gene sequencing and metabolomic analysis using gas chromatography–mass spectrometry. Probiotic supplementation significantly reduced the severity of abdominal bloating and its interference with quality of life, and improved the body image domain of the IBS-QoL. Beta diversity analysis showed significant temporal shifts in the probiotic group, while 16S rRNA sequencing revealed an increased relative abundance of Faecalibacterium prausnitzii and Blautia stercoris. Fecal metabolomic analysis further indicated elevated levels of metabolites implicated in the gut–brain axis. Multi-strain probiotic supplementation alleviated gastrointestinal symptoms and improved aspects of psychosocial well-being in adults with FBDs, potentially through modulation of the human gut microbiome. Full article

Gut microbiota has increasingly been shown to exert effects beyond the gastrointestinal tract, some of which are mediated through its metabolites, such as trimethylamine N-oxide (TMAO)—a compound converted by gut bacteria from dietary choline found predominantly in animal products that is associated with cardiovascular disease (CVD). However, a significant gap persists in human clinical trials assessing its potential causal role. This narrative review aims to present the current understanding of the gut microbiome, TMAO, and their relationship with CVD, while proposing future directions that may support the use of TMAO as a biomarker and guide potential interventions to reduce its harmful impact. Both animal and human studies have demonstrated a link between TMAO and CVD, with animal studies also indicating a causal effect—showing increased cardiovascular risk following TMAO administration and reduced risk when TMAO is eliminated. While direct extrapolation from animal models to humans is limited due to biological differences, these findings offer a foundation for the development of well-designed clinical trials in human populations. Although direct approaches to target TMAO—such as trimethylamine (TMA) lyase inhibitors and antisense oligonucleotide (ASO) therapy—have shown promising results in animal studies, they have yet to be investigated in human trials, leaving indirect strategies such as dietary changes and probiotics as the only currently available options. Full article

A systematic review was conducted to assess the effects of microgravity and space radiation on astronauts’ oral health. This review aimed to determine if these conditions increase the risk of dental and periodontal diseases, identify pre-mission dental care strategies, and specify relevant dental emergencies for astronauts to manage during missions. Following PRISMA guidelines, the review was registered on PROSPERO (CRD42023472765). Databases including PubMed, Scopus, Web of Science, Cochrane Library, and OVID Medline were searched. Of the 13 studies identified, 7 were eligible for qualitative synthesis. The included studies revealed that space conditions compromise oral health. Findings indicate changes in saliva composition, with a significant decline in salivary lysozyme levels during missions lasting 28 to 84 days. Salivary IgA levels also increased before and peaked after flights (microgravity alters fluid shear and protein folding). Viral reactivation was a key finding, with latent viruses such as Epstein–Barr virus (EBV), cytomegalovirus (CMV), and varicella zoster virus (VZV) being reactivated during missions (immune suppression and gene expression shifts under spaceflight stress). Data from a study found that 50% of crew members shed viruses in their saliva or urine, and 38% tested positive for herpesviruses. The included studies also documented alterations in the oral microbiome, including increased gastrointestinal and decreased nasal microbial diversity. This suggests alterations in salivary biomarkers, viral shedding, and microbiome changes in astronauts during long-duration missions. These changes appear associated with immune dysregulation and stress, but causality remains uncertain due to observational designs, small heterogeneous samples, and confounding factors. Although current evidence is indicative rather than definitive, these findings highlight the need for preventive dental measures prior to missions and preparedness for managing oral emergencies in-flight. Future studies should address the mechanistic separation of microgravity and radiation effects, with implications for upcoming Moon and Mars missions. Full article

In dogs, gut microbiome dysbiosis is associated with several health conditions, including gastrointestinal disease. Probiotic supplementation can support a balanced gut microbiome. This study assessed the impact of a probiotic containing a mixture of Lacticaseibacillus casei, Limosilactobacillus fermentum, Levilactobacillus brevis, and Enterococcus faecium on the gut microbiota of six dogs using short-term colonic simulations. Two groups were included, i.e., blank versus supplementation with the test product, and incubated for 48 h. Probiotic-supplemented reactors had significantly greater fermentative activity compared with the blank, as shown by lower pH levels and higher gas pressure after 6 h, 24 h, and 48 h of incubation (p < 0.05 for all). Saccharolytic fermentation also increased, with a significantly higher level of acetate at 24 h and propionate at 6 h, 24 h, and 48 h with the test product versus blank (p < 0.05 for all). There was no significant effect of the test product on alpha-diversity, but beta-diversity analysis revealed a clear separation in the microbial community composition between the test product and blank. Eight bacterial taxa were enriched with test product supplementation, including the probiotic test strains as well as Megamonas and Bacteroides species. This study, using in vitro short-term colon simulations with six canine donors, provides insights into the probiotic characteristics of the test product. Full article

Ochratoxin A (OTA) is a widespread foodborne mycotoxin that poses significant risks to both human and animal health. Upon ingestion, the gastrointestinal tract (GIT) becomes the main site of exposure, where OTA interacts directly with the intestinal epithelium and resident microbiota. Research indicates that OTA disrupts the integrity of the intestinal barrier and alters its permeability. Moreover, OTA undergoes transport and partial metabolism within the intestine before being excreted. Detoxification pathways for OTA include enzymatic degradation and adsorption by microorganisms. Notably, OTA has profound toxic effects on the gut ecosystem; it can alter the relative abundance of bacterial taxa by reducing beneficial populations and promoting opportunistic or pathogenic strains. These changes contribute to an imbalance in the microbiota, impairing host metabolic and immune functions. This dysbiosis is characterized by disrupted microbial homeostasis and impaired communication between the host and its gut microbiome. This review highlights the dual role of the intestine as both a target and a modulator of OTA toxicity. It emphasizes the importance of gut microbiota in mediating the toxicological outcomes of OTA and explores microbiome-based strategies as potential avenues for detoxification. Full article

Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder, characterized by abdominal pain, altered bowel habits (diarrhea and/or constipation) and a dysbiosis of the gut microbiome. This dysbiosis is difficult to restore via fiber supplementation, which typically promotes gas production, potentially worsening IBS symptoms. We therefore studied how two novel products, triacetin (TA; REBiome™) and a mushroom blend (MB; Hōlistiq™), modulate the microbiome of IBS subjects (n = 8) using the ex vivo SIFR^® (Systemic Intestinal Fermentation Research) technology combined with a co-culture of epithelial/immune (Caco-2/THP-1) cells. First, the IBS microbiomes revealed large interpersonal variability and an IBS-associated dysbiosis. TA increased the beneficial metabolites acetate and butyrate (~Anaerobutyricum soehngenii, Mediterraneibacter_A butyricigenes, Faecalibacterium prausnitzii). Moreover, MB stimulated a wide range of gut microbes and additionally promoted propionate. Despite more strongly increasing total short-chain fatty acid (SCFA) levels, TA induced significantly less gas production than MB. Mechanistically, acetate with TA was derived from hydrolysis, a process that indeed does not induce gas production. Notably, both TA and MB enhanced gut barrier integrity (transepithelial electrical TEER), which is related to lower symptom severity in IBS patients. Overall, our findings highlight the product-specific microbiome modulation and potential of MB, TA or combinations thereof as dietary interventions for managing IBS symptom severity. Full article

Despite growing recognition of the role of the gut microbiome in host health and in modulating pathogen activity, the dynamic and reciprocal relationship between enteric viruses and the gut microbial ecosystem remains insufficiently defined and requires further exploration. This comprehensive review examines the bidirectional interplay between the gut microbiome and enteric viral infections by addressing (i) viruses associated with gastrointestinal alterations, (ii) how enteric viral infections alter the composition and function of the gut microbiome, (iii) how the gut microbiome modulates viral infectivity and host susceptibility, and (iv) current microbial-based approaches for preventing or treating enteric viral infections. Gastrointestinal viral infections induce gut microbiome dysbiosis, marked by reductions in beneficial bacteria and increases in potentially pathogenic populations. Specific gut microorganisms can modulate host susceptibility, with certain bacterial genera increasing or decreasing infection risk and disease severity. Pattern recognition receptors in the intestinal epithelium detect microbial signals and trigger antimicrobial peptides, mucus, and interferon responses to control viral replication while maintaining tolerance to commensal bacteria. The gut microbiome can indirectly facilitate viral infections by creating a tolerogenic environment, suppressing antiviral antibody responses, and modulating interferon signaling, or directly enhance viral replication by stabilizing virions, promoting host cell attachment, and facilitating coinfection and viral recombination. In turn, commensal gut bacteria can inhibit viral entry, enhance host antiviral responses, and strengthen mucosal barrier function, contributing to protection against gastrointestinal viral infections. Probiotics and fecal microbiota transplantation constitute potential microbial-based therapeutics that support antiviral defenses, preserve epithelial integrity, and restore microbial balance. In conclusion, the role of the gut microbiome in modulating enteric viral infections represents a promising area of future investigation. Therefore, integrating microbiome insights with virology and immunology could enable predictive and personalized strategies for prevention and treatment. Full article

Psychological stress is deeply involved in the pathophysiology of gastrointestinal diseases. We investigated the effect of psychological stress on the small-intestinal environment, including gut flora, immune system, and mucosal integrity in mice subjected to chronic social defeat stress (CSDS). CSDS mice were established by exposing a C57BL/6N mouse to an ICR aggressor mouse. Stool samples were obtained to investigate its properties and the gut microbiome profile. Using small-intestinal tissues, the expression of cytokines, antimicrobial peptides, and tight junction proteins (TJPs) were examined by real-time RT-PCR and immunohistochemistry. Small-intestinal permeability was evaluated by transepithelial electrical resistance assay. For stool properties, mean Bristol scale score and fecal water content were significantly lower in the CSDS group. Pseudomonadota and Patescibacteria were significantly more abundant in the stools from CSDS mice. Among TJPs and antimicrobial peptides, the expression of Occludin, Claudin-4, and Regenerating gene IIIγ was significantly decreased in the small intestine epithelium of CSDS mice. The small-intestinal permeability was significantly increased in CSDS mice. Lipopolysaccharide immunoreactivity, the number of macrophages, and proinflammatory IL-1β expression were significantly increased in the small intestine of CSDS mice. These findings suggest that psychological stress is associated with mucosal barrier dysfunction and microinflammation in small-intestinal tissues. Full article

The gut microbiome is strongly implicated in the development of obesity and type 2 diabetes mellitus (T2DM). A recent study demonstrated that 6-week oral supplementation of Anaerostipes rhamnosivorans (ARHAM) combined with the prebiotic myo-inositol (MI) reduced fasting glucose levels in mice. In the present study, we investigated the effects of a 13-week ARHAM-MI supplementation in high-fat diet-fed mice and examined the metabolic fate of MI, including its microbial conversion into short-chain fatty acids (SCFAs), using ¹³C-MI and stable isotope tracers in the cecum, portal vein, and peripheral blood. The results showed that the ARHAM-MI group gained less weight than the MI-only and placebo groups. Analysis of intestinal mRNA and stable isotope tracing revealed that MI is primarily absorbed in the upper gastrointestinal tract, whereas microbial conversion to SCFAs predominantly occurs in the cecum and is enhanced by ARHAM. ARHAM-MI mice also showed increased cecal Gpr43 mRNA expression, indicating enhanced SCFA-mediated signaling. Notably, SCFAs derived from MI displayed distinct distribution patterns: ¹³C-butyrate was detected exclusively in the cecum, ¹³C-propionate was present in the cecum and portal vein, whereas ¹³C-acetate was the only SCFA detected in peripheral blood. Collectively, ARHAM-MI co-supplementation confers modest metabolic benefits in high-fat diet-fed mice, underscoring the need to optimize the dosage and administration frequency of ARHAM-MI to enhance its therapeutic efficacy. Full article

The expression “lung–gut–liver axis” refers to the interconnected processes occurring in the lungs, gastrointestinal tract, and liver, particularly in relation to immune function, microbial regulation, and metabolic responses. Over the past decade, growing concern has emerged regarding the detrimental impact of air pollution on liver disease. Air pollutants, including particulate matter (PM) and chemical gases such as nitrogen oxides (NOx), can influence the microbiome in the lungs and gut by generating reactive oxygen species (ROS), which induce oxidative stress and local inflammation. This redox imbalance leads to the production of altered secondary microbial metabolites, potentially disrupting both the alveolar–capillary and gut barriers. Under these conditions, microbes and their metabolites can translocate to the liver, triggering inflammation and contributing to liver diseases, particularly metabolic dysfunction-associated steatotic liver disease (MASLD), cirrhosis, and hepatocellular carcinoma (HCC). This manuscript aims to review recent findings on the impact of air pollution on liver disease pathogenesis, exploring the molecular, genetic, and microbiome-related mechanisms underlying lung–gut–liver interactions, providing insights into potential strategies to prevent or mitigate liver disease progression. Full article

Non-Saccharomyces yeasts are emerging as promising new probiotics with a beneficial effect equal to or greater than the reference probiotic yeast, Saccharomyces boulardii. Candida intermedia, a non-albicans species not considered a common human pathogen, previously demonstrated probiotic potential. In this work, our objective was to evaluate the immunomodulatory effects of C. intermedia ORQ001 in mice vaccinated with inactivated SARS-CoV-2, seeking further evidence of its probiotic activity. Murine macrophages were stimulated with C. intermedia, followed by mRNA transcription analysis via qPCR. Mice were supplemented with C. intermedia prior to SARS-CoV-2 vaccination. Antibody production was assessed by ELISA, and fecal microbiomes were analyzed using next-generation sequencing. C. intermedia significantly increased Il4 and Il13 expression while decreasing Stat3 in macrophages. Splenocytes from supplemented mice exhibited elevated transcription levels of Tnf, Ifng, Il4, Bcl6, and Stat3 after exposure to stimulatory molecules. These mice showed increased levels of anti-SARS-CoV-2 IgG and sIgA isotypes, along with higher abundances of Bacteroides spp. and Clostridium spp. in their gut microbiome. In conclusion, C. intermedia supplementation modulated the expression of key immune-related genes and enhanced humoral responses in mice. Furthermore, its influence on gastrointestinal microbiota suggests a synergistic effect on vaccine immunogenicity. These findings support the potential of C. intermedia as a novel probiotic candidate with immunomodulatory properties applicable to vaccine adjuvanticity. Full article

Over the past decade, significant attention has been directed toward understanding the role of the gut microbiome in health and disease. The gut microbiota, comprising a complex and diverse community of microorganisms, has been linked to numerous conditions, including metabolic disorders, gastrointestinal diseases, and inflammatory or autoimmune conditions. Recently, a growing body of evidence has revealed a compelling relationship between gut microbiota composition and musculoskeletal injury recovery, highlighting its potential as a novel therapeutic target. Musculoskeletal injuries, including fractures, post-traumatic osteoarthritis, and tendon or ligament injuries, commonly lead to changes in the community structure of the gut microbiota, intestinal permeability, and systemic inflammation, processes known to negatively influence tissue repair. Preclinical studies demonstrate that microbiota-targeted interventions, such as probiotics, prebiotics, and fecal microbiota transplantation, effectively restore gut barrier integrity, modulate inflammation, and normalize gut-derived metabolite profiles. Despite these promising findings, critical gaps remain in translating these effects into clinical practice, particularly regarding the mechanisms linking specific microbiota changes to improved musculoskeletal healing outcomes. Future research incorporating rigorous clinical trials, multi-omics analyses, and advanced predictive tools, including artificial intelligence and microbiome-informed digital twins, is urgently needed to fully harness the therapeutic potential of microbiome-based interventions in musculoskeletal injury recovery. This narrative review provides insights into our evolving understanding of the relationship between the gut microbiota and musculoskeletal injury and explores the potential of gut microbiota-targeted therapies for improved healing outcomes. Full article

Intensified aquaculture production has significantly increased farmed fish exposure to various stressors that compromise welfare and productivity, demanding innovative approaches to enhance sustainable production. Aquaculture environments subject fish to multiple stressors. These include high-density housing, handling, transportation, and fluctuating water quality. Such stressors activate the hypothalamic–pituitary–interrenal axis, resulting in a cascade of endocrine responses. This subsequently impairs feeding behavior, growth performance, and immune function. Psychobiotics exert beneficial effects by producing neuroactive compounds, including gamma-aminobutyric acid, short-chain fatty acids, serotonin, and dopamine. Key bacterial genera such as Lactobacillus, Bifidobacterium, Bacillus, and Enterococcus demonstrate significant psychobiotic properties. Experimental evidence from zebrafish and commercially relevant species demonstrates that psychobiotic interventions consistently reduce cortisol levels, normalize stress responses, and improve behavioral outcomes. These effects occur through the microbiome–gut–brain axis, a bidirectional system connecting the nervous and gastrointestinal systems by neural, endocrine, and immune pathways. Nevertheless, significant challenges persist, such as species-specific efficacy, limitations in mechanistic understanding, and the need for standardized evaluation protocols. This review examines psychobiotics as promising interventions for stress management in aquaculture systems. We conclude that psychobiotics may offer a sustainable approach for mitigating aquaculture stress responses and enhancing both fish welfare and production efficiency through targeted microbiome modulation. Full article