Probiotic Bifidobacterium strains and galactooligosaccharides improve intestinal barrier function in obese adults but show no synergism when used together as synbiotics

The association between dietary live microbe intake and risk of chronic kidney disease among US adults: a cross-sectional survey from NHANES (2001-2018)

BACKGROUND

Previous studies have suggested that gut dysbacteriosis may promote the onset of chronic kidney disease (CKD). However, the relationship between consumption of live microorganisms and CKD remains unclear. This study aimed to evaluate the association between dietary consumption of live microorganisms and risk of CKD.

METHODS

We conducted a cross-sectional analysis using data from the National Health and Nutrition Examination Survey (NHANES) spanning 2001 to 2018. Dietary intake was assessed through self-reported questionnaires, while CKD diagnosis was based on glomerular filtration rate and albumin-creatinine ratio measurements.

RESULTS

After adjusting for potential confounders, participants with high live microbial intake had a significantly lower risk of CKD compared to those with low intake [odds ratio (OR): 0.79, 95% confidence interval (CI): 0.68-0.91, p = 0.001]. Similarly, those with moderate/high live microbial intake exhibited a reduced CKD risk compared to the low intake group (OR: 0.87, 95% CI: 0.78-0.97, p = 0.009). Subgroup analyses revealed a significant interaction between live microbial intake and CKD risk among participants with less than a high school education, as well as among Mexican Americans and other racial groups (including multiracial) (all P values for interaction < 0.05). A U-shaped dose-response relationship was identified between microbial intake and CKD risk, with significant non-linear associations observed for high consumption levels (P for non-linearity = 0.013).

CONCLUSIONS

High dietary intake of live microorganisms is associated with a lower risk of CKD, highlighting the potential role of gut microbiota modulation in CKD prevention.

Review: Human Intestinal Barrier-Optimal Measurement and Effects of Diet in the Absence of Overt Inflammation or Ulceration

BACKGROUND

The intestinal barrier protects humans from potentially deleterious ingested material. It consists of several components: commensal organisms, mucus, and transepithelial pathways, and immune functions.

AIMS

To review, with major focus on human studies, the methods to measure intestinal barrier function in vivo and the impaired intestinal barrier function in non-inflammatory conditions, and the deleterious or beneficial effects of dietary components on the intestinal barrier.

METHODS

PUBMED literature search was intentionally focused, when possible, on human studies conducted in vivo.

RESULTS

Although many gastrointestinal, rheumatological, and degenerative neurological diseases are attributed to impaired intestinal barrier function, often termed "leaky gut," methods of accurate measurement of intestinal barrier function in vivo in humans are still being developed. In vivo measurements provide an overall assessment of barrier function at a whole organ level, whereas ex vivo or in vitro measurements using mucosal biopsies address mechanistic information at the cellular level. Several dietary components are detrimental to the barrier, including ethanol, fat, sugars, gliadin, food additives, emulsifiers, and microbial transglutaminase. Conversely, dietary components improving barrier function include fibre and metabolites such as short-chain fatty acids, anthocyanins, polyphenols, vitamins (such as A and D), zinc, specific amino acids (such as glutamine) and probiotics.

CONCLUSIONS

Currently, data are not exclusively from human studies, and research is needed to corroborate observations in animals or further validate in humans. There are several practical dietary approaches that can be instituted for restoration of the intestinal barrier in humans.

Gut Microbiota Dysbiosis: Pathogenesis, Diseases, Prevention, and Therapy

Dysbiosis refers to the disruption of the gut microbiota balance and is the pathological basis of various diseases. The main pathogenic mechanisms include impaired intestinal mucosal barrier function, inflammation activation, immune dysregulation, and metabolic abnormalities. These mechanisms involve dysfunctions in the gut-brain axis, gut-liver axis, and others to cause broader effects. Although the association between diseases caused by dysbiosis has been extensively studied, many questions remain regarding the specific pathogenic mechanisms and treatment strategies. This review begins by examining the causes of gut microbiota dysbiosis and summarizes the potential mechanisms of representative diseases caused by microbiota imbalance. It integrates clinical evidence to explore preventive and therapeutic strategies targeting gut microbiota dysregulation, emphasizing the importance of understanding gut microbiota dysbiosis. Finally, we summarized the development of artificial intelligence (AI) in the gut microbiota research and suggested that it will play a critical role in future studies on gut dysbiosis. The research combining multiomics technologies and AI will further uncover the complex mechanisms of gut microbiota dysbiosis. It will drive the development of personalized treatment strategies.

The role of dietary inflammatory index in metabolic diseases: the associations, mechanisms, and treatments

In recent years, the prevalence of metabolic diseases has increased significantly, posing a serious threat to global health. Chronic low-grade inflammation is implicated in the development of most metabolic diseases, such as type 2 diabetes mellitus (T2DM), obesity, dyslipidemia, and cardiovascular disease, serving as a link between diet and these conditions. Increasing attention has been directly toward dietary inflammatory patterns that may prevent or ameliorate metabolic diseases. The Dietary Inflammatory Index (DII) was developed to assess the inflammatory potential of dietary intake. Consequently, a growing body of research has examined the associations between the DII and the risk of several metabolic diseases. In this review, we explore the current scientific literature on the relationships between the DII, T2DM, obesity, and dyslipidemia. It summarizes recent findings and explore potential underlying mechanisms from two aspects: the interaction between diet and inflammation, and the link between inflammation and metabolic diseases. Furthermore, this review discusses the therapeutic strategies, including dietary modifications, prebiotics, and probiotics, and discusses the application of the DII in metabolic diseases, as well as future research directions.

Targeting the immuno-inflammatory-microbial network: a key strategy for sepsis treatment

Sepsis is a life-threatening condition caused by a dysregulated host response to infection, remaining a major global health challenge despite clinical advances. Therapeutic challenges arise from antibiotic misuse, incomplete understanding of its complex pathophysiology, and the unresolved interplay of immune dysregulation and microbiota disruption. Investigating microbial homeostasis in the shift from cytokine storm to immunosuppression may elucidate the interplay between microbial metabolites, immune dysfunction, and organ injury, providing a foundation for targeted therapies and drug development. Traditional Chinese Medicine (TCM) has demonstrated significant advantages in mitigating sepsis-associated cytokine storms and modulating gut microbiota homeostasis, offering a promising strategy for developing highly effective and less toxic targeted monomeric compounds. Elucidating the interactions within the immune-inflammation-microbiota network in sepsis paves the way for biomarker-driven personalized therapeutic approaches.

Probiotics and prebiotics: new treatment strategies for oral potentially malignant disorders and gastrointestinal precancerous lesions

Oral potentially malignant disorders (OPMDs) and gastrointestinal precancerous lesions (GPLs) are major public health concerns because of their potential to progress to cancer. Probiotics, prebiotics, and engineered probiotics can positively influence the prevention and management of OPMDs and GPLs. This review aims to comprehensively review the application status of probiotics, prebiotics and engineered probiotics in OPMDs and GPLs, explore their potential mechanisms of action, and anticipate their future clinical use.

Effects of Lactobacillus paracei JY062 Postbiotic on Intestinal Barrier, Immunity, and Gut Microbiota

BACKGROUND/OBJECTIVES

Research on postbiotics derived from probiotic fermented milk bases require further expansion, and the mechanisms through which they exert their effects have yet to be fully elucidated. This study utilized in vitro cell co-culture, digestion, and fermentation experiments, combined with targeted T500 technology, to elucidate the mechanism by which postbiotic Pa JY062 safeguards intestinal health. Compared to the LPS group, Pa JY062 boosted phagocytic ability in RAW264.7 macrophages, decreased NO levels, and alleviated LPS-induced excessive inflammation. Pa JY062 suppressed pro-inflammatory cytokines (IL-6, IL-17α, and TNF-α) while elevating anti-inflammatory IL-10. It prevented LPS-induced TEER reduction in Caco-2 monolayers, decreased FITC-dextran permeability, restored intestinal microvilli integrity, and upregulated tight junction genes (ZO-1, occludin, claudin-1, and E-cadherin). The hydrolysis rate of Pa JY062 progressively rose in gastrointestinal fluids in 0-120 min. At 5 mg/mL, it enriched gut microbiota diversity and elevated proportions of Limosilactobacillus, Lactobacillus, Pediococcus, and Lacticaseibacillus while augmenting the microbial production of acetic acid (120.2 ± 8.08 μg/mL), propionic acid (9.9 ± 0.35 μg/mL), and butyric acid (10.55 ± 0.13 μg/mL). Pa JY062 incorporated αs-casein/β-lactoglobulin hydrolysate (L-glutamic acid, alanine, lysine, tyrosine, phenylalanine, histidine, and arginine) to mitigate protein allergenic potential while harboring bioactive components, including tryptophan metabolites, vitamin B6 (VB6), and γ-aminobutyric acid (GABA). Pa JY062 represented a novel postbiotic with demonstrated intestinal health-promoting properties. These findings advance the current knowledge on postbiotic-mediated gut homeostasis regulation and expedite the translational development of dairy-derived postbiotic formulations.

Nanofiltration-based purification process for whole-cell transformed prebiotic galactooligosaccharides

The enrichment of galactooligosaccharides (GOS), synthesized by whole cells of Kluyveromyces marxianus 3551 in a 5.0-L bioreactor, was investigated in this study. The synthesized sugar mixture containing 17.89% (w/w of total carbohydrates) of GOS with 15.57% (w/w of total carbohydrates) of lactose, and 66.54% (w/w of total carbohydrates) monosaccharides as impurities, was subjected to nanofiltration for enrichment of GOS. Three distinct spiral wound membranes, namely, NFPS-01(polysulfone), NFCA-02 (cellulose acetate), and NFPES-03 (polyethersulfone) were tested out of which the NFPES-03 performed the best for fractionation of the GOS mixture. The polyethersulphone membrane (cut-off 400-1000 Da) was evaluated at 30 ℃ and 50 ℃, at different transmembrane pressures or TMP (15, 20, 25 bar) and a combination of high temperature (50 ℃) and low pressure (15 bar) gave the greatest difference in the trisaccharide and disaccharide/monosaccharide rejection percentages, resulting in enrichment of GOS. An analysis of the sugar concentrations in the retentate samples by high-performance liquid chromatography indicated the percentage recovery of GOS in the integrated process to be 88.8%. Measurement of the growth profile of several microbes on the nano-filtered GOS demonstrated its effectiveness as a prebiotic source.

Effect of Galactooligosaccharide on PPARs/PI3K/Akt Pathway and Gut Microbiota in High-Fat and High-Sugar Diet Combined with STZ-Induced GDM Rat Model

Gestational diabetes mellitus (GDM) is a metabolic disorder, characterized by underlying glucose intolerance, diabetes onset or first diagnosis during pregnancy. Galactooligosaccharide (GOS) is essential for consumer protection as food supplementation. However, there is limited understanding of the effects of GOS on GDM. We successfully established a GDM rat model to explore GOS whether participated in PPARs/PI3K/Akt pathway and gut microbiota metabolites to treat for GDM. In this study, compared with the GDM group, GOS administration lowered the levels of TG, LDL-C, and HDL-C in rat serum, as well as improved the pathological changes pancreatic, liver, and kidney tissues. Compared with the GDM group, the protein expressions of PPARα, PPARγ, and PPARβ/δ markedly enhanced in GOS-treated groups (P < 0.01). Moreover, GOS administration upregulated the protein expressions of PPARα, PPARβ, PPARγ, PI3K, Akt, GLUT4, Bax, and Bcl2. GOS administration altered gut microbiota metabolites, including both SCFAs and BAs. Correlation analysis revealed close relationships between gut microbiota and experimental indicators. This study indicated that GOS effectively improved GDM in rats through the modulation of PPARs/PI3K/Akt pathway and gut microbiota. Thus, the GOS could be recommended as a candidate for novel therapy of GDM.

Diversity in chemical subunits and linkages: a key molecular determinant of microbial richness, microbiota interactions, and substrate utilization

Dietary fibers play a significant role in shaping the composition and function of microbial communities in the human colon. Our understanding of the specific chemical traits of dietary fibers that influence microbial diversity, interactions, and function remains limited. Toward filling this knowledge gap, we developed a novel measure, termed Chemical Subunits and Linkages (CheSL) Shannon diversity, to characterize the effects of carbohydrate complexity on human fecal bacteria cultured in vitro under controlled, continuous flow conditions using media that systematically varied in carbohydrate composition. Our analysis revealed that CheSL Shannon diversity demonstrated a strong Pearson correlation with microbial richness across multiple fecal samples and study designs. Additionally, we observed that microbial communities in media with higher CheSL Shannon diversity scores exhibited greater peptide utilization and more connected, reproducible structures in computationally inferred microbial interaction networks. Taken together, these findings demonstrate that CheSL Shannon diversity can be a useful tool to quantify the effects of carbohydrate complexity on microbial diversity, metabolic potential, and interactions. Furthermore, our work highlights how robust and stable community data can be generated by engineering media composition and structure. These studies provide a valuable framework for future research on microbial community interactions and their potential impacts on host health.IMPORTANCEFor the human adult gut microbiota, higher microbial diversity strongly correlates with positive health outcomes. This correlation is likely due to increased community resilience that results from functional redundancy that can occur within diverse communities. While previous studies have shown that dietary fibers influence microbiota composition and function, we lack a complete mechanistic understanding of how differences in the composition of fibers are likely to functionally impact microbiota diversity. To address this need, we developed Chemical Subunits and Linkages Shannon diversity, a novel measure that describes carbohydrate complexity. Using this measure, we were able to correlate changes in carbohydrate complexity with alterations in microbial diversity and interspecies interactions. Overall, these analyses provide new perspectives on dietary optimization strategies to improve human health.

Galacto-oligosaccharides alleviate experimental lactose intolerance associated with gut microbiota in mice

Introduction

Galacto-oligosaccharides (GOS) are beneficial for alleviating lactose intolerance (LI). GOS have the ability to modify the composition of the intestinal microbiota. The development of intestinal diseases could be influenced by the composition of the gut microbiota. Nevertheless, it remains unclear whether gut microbiota exerts an effect when GOS alleviate LI, whether alterations in composition of the intestinal microbiota influence inflammatory response and lactose digestion.

Methods

We first investigated the effects of GOS on mice with established lactose intolerance. Next, we demonstrated that prophylactic supplementation with GOS also conferred similar benefits.

Results

The results showed that GOS enhanced anti-inflammatory, antioxidant, and gut barrier function. We observed that GOS mediated a change in the gut microbiome by increasing the abundance of Lactobacillus. GOS pre-supplementation reduced incident LI, enhanced anti-inflammatory, antioxidant, and gut barrier function, and markedly altered the gut microbiome by significantly enriching Bifidobacterium. Collectively, the alleviation of LI by GOS suggests an intimate involvement of probiotics.

Discussion

This study demonstrates that GOS ameliorated LI in a gut microbiota-dependent manner. Our findings provide novel evidence that GOS substitute for lactase and serve as a potential modulator of the gut microbiota for the prevention of LI.

Association of the use of nonfood prebiotics, probiotics, and synbiotics with total and cause-specific mortality: a prospective cohort study

BACKGROUND

The use of nonfood prebiotics, probiotics, and synbiotics has approximately tripled in the last 20 years. It is necessary to examine the associations of these substances with all-cause and cause-specific mortality in a large prospective cohort.

METHODS

This study included 53,333 adults from the National Health and Nutrition Examination Survey 1999-2018. All participants answered questions on the use of dietary supplements and medications, including prebiotics, probiotics, and synbiotics. Death outcomes were determined by linkage to National Death Index records through 31 December 2019. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for mortality from all causes, heart diseases, cancer, and other causes.

RESULTS

During a mean follow-up of 10.6 years, 9117 deaths were documented, including 2364 heart disease deaths, 1964 cancer deaths, and 4700 other causes deaths. Compared to nonusers, nonfood prebiotic, probiotic, and synbiotic users had a 59% (HR 0.41, 95% CI 0.30 to 0.56), 56% (HR 0.44, 95% CI 0.26 to 0.74), 49% (HR 0.51, 95% CI 0.31 to 0.83), and 64% (HR 0.36, 95% CI 0.23 to 0.59) for lower risk of all-cause, cancer, heart disease, and other causes mortality, respectively. Moreover, the inverse association of the use of prebiotics, probiotics, and synbiotics with mortality was stronger in female participants and participants without hypertension.

CONCLUSION

The use of nonfood prebiotics, probiotics, and synbiotics is significantly associated with lower all-cause mortality, as well as deaths from heart disease, cancer, and other causes.

Noninvasive Detection and Monitoring of the Integrity of the Intestinal Barrier through NIR-II Fluorescence Imaging and Colorimetric Urinalysis

The variation of the integrity of the intestinal barrier is closely related to the occurrence and progression of various diseases, making its accurate detection and monitoring essential to provide reliable information for guiding the refinement of treatment scenarios. Herein, we developed a strategy utilizing glutathione-capped gold clusters (Au-GSH) to achieve simultaneous in vivo second near-infrared (NIR-II) fluorescence imaging and in vitro colorimetric urinalysis for noninvasive detection and monitoring of intestinal barrier integrity. After oral administration, Au-GSH can demonstrate different distribution behaviors in terms of the variation of intestinal barrier integrity. Specifically, Au-GSH could selectively permeate through compromised intestinal barrier to be distributed into the bladder in view of its ultrasmall size below the glomerular filtration cutoff, leading to the rapid excretion through urine. Such process can be visually profiled by collecting NIR-II fluorescence (>1100 nm) emitting from Au-GSH in a noninvasive real-time manner. By virtue of the peroxidase-like activity of Au-GSH, the simple colorimetric urinalysis was further established for evaluating the integrity of the intestinal barrier, advancing the detection and monitoring performance. As a result, our developed strategy successfully detected the damage of intestinal barrier integrity in ulcerative colitis (UC) mice, a common disease characterized by compromised intestinal barrier integrity. Excitingly, the monitoring of restoration of intestinal barrier integrity in both therapeutic and preventative modes for UC mice was also realized by our strategy, making it a promising diagnosis scenario for diseases related to the variation of intestinal barrier integrity.

In vitro investigations on the impact of fermented dairy constituents on fecal microbiota composition and fermentation activity

Fermented dairy constitutes a major dietary source and contains lactose as the main carbohydrate and living starter cultures, which can encounter the intestinal microbiota after ingestion. To investigate whether dairy-related nutritional and microbial modulation impacted intestinal microbiota composition and activity, we employed static fecal microbiota fermentations and a dairy model system consisting of lactose and Streptococcus thermophilus wild type and β-galactosidase deletion mutant. In addition, we conducted single-culture validation studies. 16S rRNA gene-based microbial community analysis showed that lactose increased the abundance of Bifidobacteriaceae and Anaerobutyricum and Faecalibacterium spp. The supplied lactose was hydrolyzed within 24 h of fermentation and led to higher expression of community-indigenous β-galactosidases. Targeted protein analysis confirmed that bifidobacteria contributed most β-galactosidases together with other taxa, including Escherichia coli and Anaerobutyricum hallii. Lactose addition led to higher (P < 0.05) levels of butyrate compared to controls, likely due to lactate-based cross-feeding and direct lactose metabolism by butyrate-producing Anaerobutyricum and Faecalibacterium spp. Representatives of both genera used lactose to produce butyrate in single cultures. When supplemented at around 5.5 log cells mL-1, S. thermophilus or its β-galactosidase-negative mutant outnumbered the indigenous Streptococcaceae population at the beginning of fermentation but had no impact on lactose utilization and final short-chain fatty acid profiles.

IMPORTANCE

The consumption of fermented food has been linked to positive health outcomes, possibly due to interactions of food components with the intestinal microbiota. This study brings forward new insights into how major constituents of fermented dairy affect intestinal microbial ecology and activity when supplied together or alone. We provide evidence that lactose availability increased the production of butyrate by fecal microbiota through cross-feeding and did not observe a contribution of starter cultures to lactose metabolism, possibly due to a lack of competitiveness. The methodological setup used in this study can be implemented in future investigations to determine the impact of other fermented foods and their major components on intestinal microbiota composition and activity.

Ameba-inspired strategy enhances probiotic efficacy via prebound nutrient supply

Nutrient competition with indigenous microbes or pathogens presents a significant challenge for oral probiotic efficacy. To address this issue, we develop an ameba-inspired food-carrying strategy (AIFS) by prebinding ginger-derived exosome-like nanoparticles (GELNs) onto probiotics as food depots. AIFS enables probiotics to efficiently and exclusively consume GELNs in situ, even in the presence of competing bacteria. This results in up to 21 times higher uptake efficiency compared to unengineered probiotics, dramatically accelerating probiotic proliferation. Meanwhile, AIFS potentiates probiotics' resistance to multiple GI stressors. In a murine model of colitis, AIFS can improve the abundance of probiotics and inhibit pathogens, maintaining intestinal flora homeostasis. Additionally, it can upregulate the anti-inflammatory IL-10, reduce the proinflammatory IL-1β, and repair damaged intestinal mucus. Thereby, AIFS displays potently elevated prophylactic and therapeutic efficacy for colitis mice. This work provides a method for microbial engineering, with broad implications for microbiotherapy and gut health.

Unveiling roles of beneficial gut bacteria and optimal diets for health

The gut microbiome plays a pivotal role in human health, influencing digestion, immunity, and disease prevention. Beneficial gut bacteria such as Akkermansia muciniphila, Adlercreutzia equolifaciens, and Christensenella minuta contribute to metabolic regulation and immune support through bioactive metabolites like short-chain fatty acids (SCFAs). Dietary patterns rich in prebiotics, fermented foods, and plant-based bioactive compounds, including polyphenols and flavonoids, promote microbiome diversity and stability. However, challenges such as individual variability, bioavailability, dietary adherence, and the dynamic nature of the gut microbiota remain significant. This review synthesizes current insights into gut bacteria's role in health, emphasizing the mechanisms by which dietary interventions modulate microbiota. Additionally, it highlights advancements in microbiome-targeted therapies and the transformative potential of personalized nutrition, leveraging microbiota profiling and artificial intelligence (AI) to develop tailored dietary strategies for optimizing gut health and mitigating chronic inflammatory disorders. Addressing these challenges requires a multidisciplinary approach that integrates scientific innovation, ethical frameworks, and practical implementation strategies.

Effects of fructooligosaccharides and Lactobacillus reuteri on the composition and metabolism of gut microbiota in students

Fructooligosaccharides (FOSs) and Lactobacillus reuteri have shown great potential in treating gastrointestinal diseases by regulating gut microbiota and metabolites. However, the synergistic effect between these two remains unclear. In this study, an in vitro fermentation model was constructed to investigate the regulatory effects of FOSs and L. reuteri on the gut microbiota of healthy student populations. After 24 hours of fecal fermentation, the results indicated that the experimental group added with FOSs had increased relative abundances of Bifidobacterium and Lactobacillus, while it exhibited lower relative abundances of Escherichia-Shigella and Bacteroides. Conversely, the groups added with L. reuteri had higher relative abundances of Bacillus and unclassified_c_Bacilli. The results of microbial metabolism revealed that the addition of FOSs produced a large amount of acetic acid, but reduced the contents of propionic acid, butyric acid, isobutyric acid, and isovaleric acid, along with reducing the production of H2, H2S and NH3. In contrast, the addition of L. reuteri had no significant effect on metabolism. Compared to the single additions, the combination of FOSs and L. reuteri had its advantages and had a more balanced microbial structure and metabolic regulation similar to the addition of FOSs alone. Additionally, correlation analysis revealed a negative correlation between gas production and Bifidobacterium, Lactobacillus, and Bacillus, and a positive correlation with Escherichia-Shigella and Bacteroides. Moreover, the formation of acetic acid was positively correlated with Bifidobacterium and negatively correlated with Escherichia-Shigella. These findings demonstrated that the combination of FOSs and L. reuteri can effectively synergistically regulate the fecal microbiome of students. This study can provide a theoretical reference for the precise development of functional foods. However, the regulatory mechanisms need further in-depth investigation.

The effect of oral synbiotics on the gut microbiota and inflammatory biomarkers in healthy adults: a systematic review and meta-analysis

CONTEXT

Prior research has explored the effect of synbiotics, the combination of probiotics and prebiotics, on the gut microbiota in clinical populations. However, evidence related to the effect of synbiotics on the gut microbiota in healthy adults has not been reviewed to date.

OBJECTIVE

A systematic review and meta-analysis was conducted to comprehensively investigate the effect of synbiotics on the gut microbiota and inflammatory markers in populations of healthy adults.

DATA SOURCES

Scopus, PubMed, Web of Science, ScienceDirect, MEDLINE, CINAHL, and The Cochrane Library were systematically searched to retrieve randomized controlled trials examining the primary outcome of gut microbiota or intestinal permeability changes after synbiotic consumption in healthy adults. Secondary outcomes of interest were short-chain fatty acids, inflammatory biomarkers, and gut microbiota diversity.

DATA EXTRACTION

Weighted (WMD) or standardized mean difference (SMD) outcome data were pooled in restricted maximum likelihood models using random effects. Twenty-seven articles reporting on 26 studies met the eligibility criteria (n = 1319).

DATA ANALYSIS

Meta-analyses of 16 studies showed synbiotics resulted in a significant increase in Lactobacillus cell count (SMD, 0.74; 95% confidence interval [CI], 0.15, 1.33; P = 0.01) and propionate concentration (SMD, 0.22; 95% CI, 0.02, 0.43; P = 0.03) compared with controls. A trend for an increase in Bifidobacterium relative abundance (WMD, 0.97; 95% CI, 0.42, 2.52; P = 0.10) and cell count (SMD, 0.82; 95% CI, 0.13, 1.88; P = 0.06) was seen. No significant differences in α-diversity, acetate, butyrate, zonulin, IL-6, CRP, or endotoxins were observed.

CONCLUSION

This review demonstrates that synbiotics modulate the gut microbiota by increasing Lactobacillus and propionate across various healthy adult populations, and may result in increased Bifidobacterium. Significant variations in synbiotic type, dose, and duration should be considered as limitations when applying findings to clinical practice.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO no. CRD42021284033.

Colonization of stenotrophomonas and its associated microbiome between paired primary colorectal cancers and their lung metastatic tumors (experimental studies)

The role of gut microbiome in colorectal cancer (CRC) lung metastases is still unclear. Herein, we collected primary colorectal tumors, matched lung metastasis, and adjacent normal colon from seven patients for 16S rRNA sequencing to evaluate microbiome signature in distant site metastasis and analyze prognosis. Fecal samples from 19 non-metastases CRC patients and 11 CRC lung metastases patients were analyzed for validation. Our efforts led to a discovery of comprehensive microbiome in CRC lung metastatic tumors, characterized by a decreased microbial diversity and an increase bacterial interaction between gram-negative bacteria Stenotrophomonas and Brevundimonas . The primary-metastatic tumor pairs harbored highly similar microbial composition in both genus and species level, especially the high level of Stenotrophomonas maltophilia . Correspondingly, the S. maltophilia levels were positively associated with poor prognosis and cancer progression. Our work highlights the great potential of S. maltophilia and its associated microbiome as biomarkers in pathogenesis and prognosis of CRC lung metastases.

Early-life exposure to polystyrene micro- and nanoplastics disrupts metabolic homeostasis and gut microbiota in juvenile mice with a size-dependent manner

Early-life exposure to different sizes of micro- and nanoplastics (MNPs) affects biotoxicity, which is related not only to the dose but also directly to particle size. In this study, pregnant ICR mice received drinking water containing 5 μm polystyrene microplastics (5 μm PS-MPs) or 0.05 μm polystyrene nanoplastics (0.05 μm PS-NPs) from pregnancy to the end of lactation. Histopathological and molecular biological detection, 16s rRNA sequencing for intestinal flora analysis, and targeted metabolomics analysis were used to look into how early-life exposure to MNPs of various sizes affects young mice's growth and development, gut flora, and metabolism. The outcomes showed that 0.05 μm and 5 μm PS-MNPs can pass through the placental and mammary barriers, and MNPs accumulating in various organs were size-dependent: the greater the accumulation in organs, the smaller the particle size. Further studies found that the larger 5 μm PS-MPs caused only small accumulation in organs, with the main health hazard being the disruption of intestinal barrier and liver function, indirectly causing gut dysbiosis and metabolic disorders. In contrast, the smaller 0.05 μm PS-NPs caused excessive accumulation in organs, not only impaired the function of the intestine and liver, but also caused direct mechanical damage to physical tissues, and ultimately resulted in more severe intestinal and metabolic disorders. Our findings underline the size-dependent risks associated with micro- and nanoplastics exposure early in life and highlight the necessity for tailored approaches to address health damages from early MNPs exposure.

A glutenin protein corona ameliorated TiO2 nanoparticle-induced gut barrier dysfunction and altered the gut microbiota composition

Previously, we found that glutenin proteins formed a protein corona around food-grade titanium dioxide (TiO2) nanoparticles. The protein corona would alter the gastrointestinal behavior and biological activity of the nanoparticles. Here, in this study, the influence of protein corona formation on the adverse effects of TiO2 nanoparticles on gut barrier function using in vitro and in vivo assays and the potential mechanism were investigated and elucidated. Our findings showed that the presence of the protein corona mitigated gut barrier injury caused by TiO2 nanoparticles while increasing gene expression for tight junction proteins; for example, in vitro gastrointestinal digestion and fermentation experiments showed that the glutenin-TiO2 protein corona was relatively stable to digestion and influenced the composition of the gut microbiota. Specifically, the glutenin-TiO2 protein corona increased the relative abundance of beneficial bacteria such as Bifidobacterium, Parasutterella, and Bacillus while reducing the relative abundance of harmful bacteria like Streptococcus. Moreover, the formation of the protein corona reduced the cytotoxicity of the TiO2 nanoparticles to Caco-2 and RAW264.7 cells. Mechanistically, we found that the presence of the glutenin-TiO2 protein corona decreased the production of reactive oxygen species and increased the mitochondrial membrane potential in both Caco-2 and RAW264.7 cells compared to TiO2 nanoparticles alone. This study provides valuable mechanistic insights into the potential biological effects of protein corona formation around food inorganic nanoparticles in the food industry.

A Review of the Consequences of Gut Microbiota in Neurodegenerative Disorders and Aging

Age-associated alterations in the brain lead to cognitive deterioration and neurodegenerative disorders (NDDs). This review with a particular focus on Alzheimer's disease (AD), emphasizes the burgeoning significance of the gut microbiota (GMB) in neuroinflammation and its impact on the gut-brain axis (GBA), a communication conduit between the gut and the central nervous system (CNS). Changes in the gut microbiome, including diminished microbial diversity and the prevalence of pro-inflammatory bacteria, are associated with AD pathogenesis. Promising therapies, such as fecal microbiota transplantation (FMT), probiotics, and prebiotics, may restore gut health and enhance cognitive performance. Clinical data remain insufficient, necessitating further research to elucidate causes, enhance therapy, and consider individual variances. This integrative approach may yield innovative therapies aimed at the GMB to improve cognitive function and brain health in older people.

Assessing the impact of gut microbiota and metabolic products on acute lung injury following intestinal ischemia-reperfusion injury: harmful or helpful?

Ischemia-reperfusion injury (IRI) is a common and clinically significant form of tissue damage encountered in medical practice. This pathological process has been thoroughly investigated across a variety of clinical settings, including, but not limited to, sepsis, organ transplantation, shock, myocardial infarction, cerebral ischemia, and stroke. Intestinal IRI, in particular, is increasingly recognized as a significant clinical entity due to marked changes in the gut microbiota and their metabolic products, often described as the body's "second genome." These changes in intestinal IRI lead to profound alterations in the gut microbiota and their metabolic outputs, impacting not only the pathology of intestinal IRI itself but also influencing the function of other organs through various mechanisms. Notable among these are brain, liver, and kidney injuries, with acute lung injury being especially significant. This review seeks to explore in depth the roles and mechanisms of the gut microbiota and their metabolic products in the progression of acute lung injury initiated by intestinal IRI, aiming to provide a theoretical basis and directions for future research into the treatment of related conditions.

Bondarzewia dickinsii Against Colitis-Associated Cancer Through the Suppression of the PI3K/AKT/COX-2 Pathway and Inhibition of PGE2 Production in Mice

BACKGROUND

Bondarzewia dickinsii (BD) is a newly discovered edible mushroom with rich nutritional components. This study presents a thorough analysis of the components of BD, examining its inhibitory effects and the underlying mechanisms by which BD influences colitis-associated cancer (CAC).

METHODS

AOM/DSS-induced CAC mice (male C57BL/6) were used, and a histopathological analysis, intestinal microbiota assessment, and metabolomics profiling were carried out, as well as an evaluation of relevant proteins and factors, to investigate the CAC-inhibitory effects of BD.

RESULTS

BD is rich in nutritional components, including a total sugar content of 37.29% and total protein content of 24.9%. BD significantly diminished colon inflammation, as well as the size and quantity of tumors. In addition, BD modified the diversity of intestinal microbiota and changed the levels of 19 serum metabolites, including arachidonic acid. BD significantly reduced prostaglandin E2 (PGE2) and cyclooxygenase-2 (COX-2) in colon tissue. Furthermore, it was found to inhibit the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/COX-2 signaling pathway.

CONCLUSIONS

In general, BD inhibited the onset and progression of CAC by modulating the composition of intestinal microbiota and metabolite levels, suppressing the PI3K/AKT/COX-2 pathway, and decreasing PGE2 expression. This study provides a significant reference for the development of BD as a dietary supplement and pharmaceutical agent in the treatment of CAC.

Design and reporting of prebiotic and probiotic clinical trials in the context of diet and the gut microbiome

Diet is a major determinant of the gastrointestinal microbiome composition and function, yet our understanding of how it impacts the efficacy of prebiotics and probiotics is limited. Here we examine current evidence of dietary influence on prebiotic and probiotic efficacy in human studies, including potential mechanisms. We propose that habitual diet be included as a variable in prebiotic and probiotic intervention studies. This recommendation is based on the potential mechanisms via which diet can affect study outcomes, either directly or through the gut microbiome. We consider the challenges and opportunities of dietary assessment in this context. Lastly, we provide recommendations for the design, conduct and reporting of human clinical trials of prebiotics and probiotics (and other biotic interventions) to account for any effect of diet and nutrition.

Maternal Obesity and Differences in Child Urine Metabolome

Background/objective: Approximately one-third of pregnant individuals in the U.S. are affected by obesity, which can adversely impact the in utero environment and offspring. This study aimed to investigate the differences in urine metabolomics between children exposed and unexposed to maternal obesity. Methods: In a study nested within a larger pregnancy cohort of women-offspring pairs, we measured untargeted metabolomics using liquid chromatography-mass spectrometry in urine samples from 68 children at 4-8 years of age. We compared metabolite levels between offspring exposed to maternal obesity (body mass index [BMI] ≥ 30.0 kg/m2) vs. unexposed (maternal BMI 18.5-24.9 kg/m2) and matched them on covariates, using two-sample t-tests, with additional sensitivity analyses based on children's BMI. This study reports statistically significant results (p ≤ 0.05) and potentially noteworthy findings (fold change > 1 or 0.05 < p < 0.15), considering compounds' involvement in common pathways or similar biochemical families. Results: The mean (SD) maternal age at study enrollment was 28.0 (6.3) years, the mean child age was 6.6 (0.8) years, 56% of children were male, and 38% of children had a BMI in the overweight/obese range (BMI ≥ 85th percentile). Children exposed to maternal obesity had lower levels of 5-hydroxyindole sulfate and 7-hydroxyindole sulfate and higher levels of secondary bile acids. Phenylacetic acid derivatives were lower in offspring exposed to obesity and in offspring who had a current BMI in the overweight/obese range. Exposure to maternal obesity was associated with lower levels of androgenic steroid dehydroepiandrosterone sulfate (DHEA-S). Conclusions: In this preliminary study, children exposed to maternal obesity in utero had differences in microbiome-related metabolites in urine suggestive of altered microbial catabolism of tryptophan and acetylated peptides. Some of these differences were partially attributable to the offspring's current BMI status. This study highlights the potential of urine metabolomics to identify biomarkers and pathways impacted by in utero exposure to maternal obesity.

Effectiveness and safety study of formula containing probiotics, prebiotics, synbiotics on fullterm infants' growth - a systematic review and meta-analysis of randomized controlled study

BACKGROUND AND OBJECTIVE

Probiotics, prebiotics, and synbiotics, are hot topics of research and have been shown to improve the body's disease state and promote health. Analysis of whether infant formula containing probiotcs, prebiotics, synbiotics is beneficial to infant and child growth.

METHODS

We systematically searched multiple electronic databases (PubMed, Web of Science, The Cochrane Library, Embase) to identify eligible studies published from 1966 to December 25, 2022. Included studies were randomized controlled trials (RCTs) studying the influence of milk powder containing probiotcs, prebiotics, synbiotics on infants and children's growth. RevMan 5.4 was used to analyze the data.

RESULTS

A total of 55 RCTs with a total sample size of 8868 participants met the inclusion criteria. Milk powder with probiotics, prebiotics, synbiotics does not significantly improve the growth of infants and children (Weight, height, BMI, and Head Circumference); The incidence of minor adverse events (OR 0.88, 95% CI 0.70-1.11 P = 0.28) and serious adverse events (OR 0.92, 95% CI 0.62-1.36 P = 0.67) was also comparable to the control group; The intestinal microbial diversity of infants consuming probiotcs, prebiotics, synbiotics supplemented formula was lower than that of infants consuming formula without probiotcs, prebiotics, synbiotics (SMD -0.88, 95% CI -1.66- -0.1 P = 0.03), but the abundance of individual beneficial flora was increased. (SMD 1.62, 95%CI 0.61-2.62 P = 0.002). In particular, the abundance of Lactobacillus (SMD 1.62, 95% CI 0.61-2.62 P = 0.002). For metabolites, synbiotics increased fecal antibody concentrations (SMD 0.47, 95% CI 0.08-0.86 P = 0.02), but fecal short-chain fatty acid concentrations remained balanced in both groups (SMD 0.05 95% CI -0.17-0.28 P = 0.64). Compared to the control group, infants who consumed formula with prebiotics had softer stools (SMD -1.47, 95% CI -2.23 to -0.7 P = 0.002) and lower stool pH (SMD -0.82, 95% CI -1.15- -0.5 P < 0.00001), there is also more frequency of bowel movements (SMD 0.27, 95% CI 0.09-0.44 P = 0.002).

CONCLUSIONS

Probiotcs, prebiotics, synbiotics supplemented formulas significantly increased abundance of individual probiotics, alter intestinal antibody secretion, and improve bowel movements. Incidence of adverse reactions did not differ between the two groups. So we can choose formula-supplemented probiotcs, prebiotics, synbiotics to maintain the intestinal health of infants.

An insoluble cellulose nanofiber with robust expansion capacity protects against obesity

An imbalance between energy intake and energy expenditure predisposes obesity and its related metabolic diseases. Soluble dietary fiber has been shown to improve metabolic homeostasis mainly via microbiota reshaping. However, the application and metabolic effects of insoluble fiber are less understood. Herein, we employed nanotechnology to design citric acid-crosslinked carboxymethyl cellulose nanofibers (CL-CNF) with a robust capacity of expansion upon swelling. Supplementation with CL-CNF reduced food intake and delayed digestion rate in mice by occupying stomach. Besides, CL-CNF treatment mitigated diet-induced obesity and insulin resistance in mice with enhanced energy expenditure, as well as ameliorated inflammation in adipose tissue, intestine and liver and reduced hepatic steatosis, without any discernible signs of toxicity. Additionally, CL-CNF supplementation resulted in enrichment of probiotics such as Bifidobacterium and decreased in the relative abundances of deleterious microbiota expressing bile salt hydrolase, which led to increased levels of conjugated bile acids and inhibited intestinal FXR signaling to stimulate the release of GLP-1. Taken together, our findings demonstrate that CL-CNF administration protects mice from diet-induced obesity and metabolic dysfunction by reducing food intake, enhancing energy expenditure and remodeling gut microbiota, making it a potential therapeutic strategy against metabolic diseases.

Benefits and Challenges of Encapsulating Bifidobacterium Probiotic Strains with Bifidogenic Prebiotics

Bifidobacteria offer remarkable health benefits when added to probiotic formulations, contributing to the burgeoning market driven by increased awareness among consumers and healthcare providers. However, several pivotal challenges must be crossed: strain selection, encapsulation wall materials, compatible food matrices, and the intricate interplay among these factors. An approach to address these challenges involves exploring bifidogenic substrates as potential encapsulation materials. This strategy has the potential to enhance bifidobacteria viability within the demanding gastrointestinal environment, extend shelf life, and promote synergistic interactions that promote bifidobacteria survival. Nonetheless, it is crucial to acknowledge that the relationship between bifidogenic substrates and bifidobacterial metabolism is complex and multifaceted. Consequently, despite the promising outlook, it is important to emphasize that this approach requires in-depth investigation, as the intricate interplay between these elements constitutes a rich area of ongoing research. This pursuit aims to ultimately deliver consumers a product that can genuinely improve their health and well-being.

Progress in the study of the correlation between sepsis and intestinal microecology

Sepsis, a disease with high incidence, mortality, and treatment costs, has a complex interaction with the gut microbiota. With advances in high-throughput sequencing technology, the relationship between sepsis and intestinal dysbiosis has become a new research focus. However, owing to the intricate interplay between critical illness and clinical interventions, it is challenging to establish a causal relationship between sepsis and intestinal microbiota imbalance. In this review, the correlation between intestinal microecology and sepsis was summarized, and new therapies for sepsis intervention based on microecological target therapy were proposed, and the shortcomings of bacterial selection and application timing in clinical practice were addressed. In conclusion, current studies on metabolomics, genomics and other aspects aimed at continuously discovering potential probiotics are all providing theoretical basis for restoring intestinal flora homeostasis for subsequent treatment of sepsis.

Highly accurate and sensitive absolute quantification of bacterial strains in human fecal samples

BACKGROUND

Next-generation sequencing (NGS) approaches have revolutionized gut microbiome research and can provide strain-level resolution, but these techniques have limitations in that they are only semi-quantitative, suffer from high detection limits, and generate data that is compositional. The present study aimed to systematically compare quantitative PCR (qPCR) and droplet digital PCR (ddPCR) for the absolute quantification of Limosilactobacillus reuteri strains in human fecal samples and to develop an optimized protocol for the absolute quantification of bacterial strains in fecal samples.

RESULTS

Using strain-specific PCR primers for L. reuteri 17938, ddPCR showed slightly better reproducibility, but qPCR was almost as reproducible and showed comparable sensitivity (limit of detection [LOD] around 104 cells/g feces) and linearity (R2 > 0.98) when kit-based DNA isolation methods were used. qPCR further had a wider dynamic range and is cheaper and faster. Based on these findings, we conclude that qPCR has advantages over ddPCR for the absolute quantification of bacterial strains in fecal samples. We provide an optimized and easy-to-follow step-by-step protocol for the design of strain-specific qPCR assays, starting from primer design from genome sequences to the calibration of the PCR system. Validation of this protocol to design PCR assays for two L. reuteri strains, PB-W1 and DSM 20016 T, resulted in a highly accurate qPCR with a detection limit in spiked fecal samples of around 103 cells/g feces. Applying our strain-specific qPCR assays to fecal samples collected from human subjects who received live L. reuteri PB-W1 or DSM 20016 T during a human trial demonstrated a highly accurate quantification and sensitive detection of these two strains, with a much lower LOD and a broader dynamic range compared to NGS approaches (16S rRNA gene sequencing and whole metagenome sequencing).

CONCLUSIONS

Based on our analyses, we consider qPCR with kit-based DNA extraction approaches the best approach to accurately quantify gut bacteria at the strain level in fecal samples. The provided step-by-step protocol will allow scientists to design highly sensitive strain-specific PCR systems for the accurate quantification of bacterial strains of not only L. reuteri but also other bacterial taxa in a broad range of applications and sample types. Video Abstract.

Utilizing pigs as a model for studying intestinal barrier function

Intestinal permeability has been extensively studied, particularly in gastrointestinal diseases such as inflammatory bowel disease, food allergy, visceral disease, celiac disease, and Crohn’s disease. These studies have established that changes in intestinal permeability contribute to the pathogenesis of many gastrointestinal and systemic diseases. While numerous works in the 20th century focused on this topic, it remains relevant for several reasons. Despite the development of new research techniques, it is still unclear whether changes in intestinal permeability are the primary mechanism initiating the disease process or if they occur secondary to an ongoing chronic inflammatory process. Investigating the possibility of stabilizing the intestinal barrier, thereby reducing its permeability preemptively to prevent damage and after the damage has occurred, may offer new therapeutic approaches. Increased intestinal permeability is believed to lead to reduced nutrient absorption, resulting in decreased immunity and production of digestive enzymes.

Do high-protein diets have the potential to reduce gut barrier function in a sex-dependent manner?

PURPOSE

Impaired gut barrier function is associated with systemic inflammation and many chronic diseases. Undigested dietary proteins are fermented in the colon by the gut microbiota which produces nitrogenous metabolites shown to reduce barrier function in vitro. With growing evidence of sex-based differences in gut microbiotas, we determined whether there were sex by dietary protein interactions which could differentially impact barrier function via microbiota modification.

METHODS

Fermentation systems were inoculated with faeces from healthy males (n = 5) and females (n = 5) and supplemented with 0.9 g of non-hydrolysed proteins sourced from whey, fish, milk, soya, egg, pea, or mycoprotein. Microbial populations were quantified using fluorescence in situ hybridisation with flow cytometry. Metabolite concentrations were analysed using gas chromatography, solid phase microextraction coupled with gas chromatography-mass spectrometry and ELISA.

RESULTS

Increased protein availability resulted in increased proteolytic Bacteroides spp (p < 0.01) and Clostridium coccoides (p < 0.01), along with increased phenol (p < 0.01), p-cresol (p < 0.01), indole (p = 0.018) and ammonia (p < 0.01), varying by protein type. Counts of Clostridium cluster IX (p = 0.03) and concentration of p-cresol (p = 0.025) increased in males, while females produced more ammonia (p = 0.02), irrespective of protein type. Further, we observed significant sex-protein interactions affecting bacterial populations and metabolites (p < 0.005).

CONCLUSIONS

Our findings suggest that protein fermentation by the gut microbiota in vitro is influenced by both protein source and the donor's sex. Should these results be confirmed through human studies, they could have major implications for developing dietary recommendations tailored by sex to prevent chronic illnesses.

Metabolic Regulation of Microbiota and Tissue Response

The microbiota in our gut regulates the sophisticated metabolic system that the human body has, essentially converting food into energy and the building blocks for various bodily functions. In this review, we discuss the multifaceted impact of the microbiota on host nutritional status by producing short-chain fatty acids, influencing gut hormones and mediating bile acid metabolism, and the key role in maintaining intestinal barrier integrity and immune homeostasis. Understanding and leveraging the power of the gut microbiome holds tremendous potential for enhancing human health and preventing various diseases.

Bifidobacterium Bloodstream Infection in a Lymphoma Patient Undergoing Chemotherapy: A Case Study and Implications for Probiotic Use

BACKGROUND Fermenting bacilli producing lactic acid, including Bifidobacterium spp., are supposed to have low pathogenicity and no virulence for humans. Probiotics consisting of those fermenting bacilli can prevent and treat symptomatic gastrointestinal conditions, such as diarrhea. We use probiotics even in cancer patients, those who are immunocompromised, because a preferable effect to the intestinal commensal microbiome has been shown in a recent report. Some case reports warn of a rare risk of bloodstream infection caused by probiotics. However, complete prohibition of probiotic use in cancer patients abandons the benefits. CASE REPORT A 75-year-old Japanese woman with malignant lymphoma was treated with immune-chemotherapy regimen consisting of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP). The patient had onset of febrile neutropenia during chemotherapy and had Bifidobacterium breve bloodstream infection on day 8 after the eighth R-CHOP treatment. She had usually eaten commercial yogurt every morning. This yogurt was produced from only Lactobacillus bulgaricus and Streptococcus thermophilus. It did not contain Bifidobacterium breve. The bloodstream infection in this case looked like it derived from her food; however, it was not associated with her habitual foods. The patient was treated with meropenem for 8 days and experienced complete remission of the bloodstream infection. CONCLUSIONS We speculate that fermenting bacilli can also be a source of bloodstream infection, not necessarily associated with probiotic strains, in cancer patients treated with chemotherapy. Additionally, we recommend that probiotics can alleviate alimentary tract symptoms in immunocompromised patients.

Effects of Limosilactobacillus reuteri strains PTA-126787 and PTA-126788 on intestinal barrier integrity and immune homeostasis in an alcohol-induced leaky gut model

Intestinal barrier is a first line of defense that prevents entry of various harmful substances from the lumen into the systemic environment. Impaired barrier function with consequent translocation of harmful substances into systemic circulation ("leaky gut") is a central theme in many gastrointestinal, autoimmune, mental, and metabolic diseases. Probiotics have emerged as a promising strategy to maintain intestinal integrity and address "leaky gut". Using in silico, in vitro and avian in vivo analyses, we previously showed that two novel L. reuteri strains, PTA-126787 (L. reuteri 3630) and PTA-126788 (L. reuteri 3632), isolated from broiler chickens possess favorable safety profiles. Consistent with a recent study, here we show that L. reuteri 3630 and 3632 are phylogenetically similar to human L. reuteri strains. Daily administration of high doses of L. reuteri 3630 and 3632 to Sprague Dawley rats for 28 days was found to be safe with no adverse effects. More importantly, administration of L. reuteri 3630 and 3632 significantly reduced markers associated with alcohol-induced leaky gut, by downregulating inflammatory cytokines and upregulating anti-inflammatory cytokines in an alcohol model of leaky gut in mice. While L. reuteri 3630 cells and supernatant showed no activation, L. reuteri 3632 cells but not supernatant showed activation of AhR, a key transcription factor that regulates gut and immune homeostasis. L. reuteri 3630 is creamish white in morphology typical of Lactobacillus species and L. reuteri 3632 displays a unique orange pigmentation, which was stable even after passaging for 480 generations. We identified a rare polyketide biosynthetic gene cluster in L. reuteri 3632 that likely encodes for the orange-pigmented secondary metabolite. Similar to L. reuteri 3632 cells, the purified orange metabolite activated AhR. All together, these data provide evidence on the phylogenetic relatedness, safety, efficacy, and one of the likely mechanisms of action of L. reuteri 3630 and 3632 for potential probiotic applications to address "leaky gut" and associated pathologies in humans.

Neuromicrobiology Comes of Age: The Multifaceted Interactions between the Microbiome and the Nervous System

The past decade has seen an explosion in our knowledge about the interactions between gut microbiota, the central nervous system, and the immune system. The gut-brain axis has recently gained much attention due to its role in regulating host physiology. This review explores recent findings concerning potential pathways linking the gut-brain axis to the initiation, pathophysiology, and development of neurological disorders. Our objective of this work is to uncover causative factors and pinpoint particular pathways and therapeutic targets that may facilitate the translation of experimental animal research into practical applications for human patients. We highlight three distinct yet interrelated mechanisms: (1) disruptions of both the intestinal and blood-brain barriers, (2) persistent neuroinflammation, and (3) the role of the vagus nerve.

A double-blind intervention trial in healthy women demonstrates the beneficial impact on Bifidobacterium with low dosages of prebiotic galacto-oligosaccharides

Introduction

Galacto-oligosaccharides (GOS) are well-substantiated prebiotic substrates. Multiple studies have demonstrated a positive impact of GOS on gut microbiota composition and activity, so-far mainly related to Bifidobacterium. However, data on the beneficial impact at lower dosages in a healthy female population are limited. The primary aim of the current study was to reveal the effect of low dosages (1.3 and 2.0 g) of GOS on fecal Bifidobacterium abundance in healthy women. Other outcomes included the effect of low dosage of GOS on overall fecal microbiota composition and on self-perceived GI comfort, sleep quality and mental wellbeing.

Method

Eighty-eight healthy women (42-70 years, BMI 18.7-30 kg/m2) were included in this randomized, parallel, double-blind study of 6 weeks. The participants were stratified for fiber intake, BMI and age and randomized to consume either 1.3 or 2.0 g of GOS per day for 3 weeks after a control period of 3 weeks without any intervention. Fecal samples were collected for shotgun metagenomics sequencing at the start (t = -3) and end (t = 0) of the control period and at the end of the intervention period (t = 3). Self-perceived gut comfort, sleep quality, and mental wellbeing were assessed weekly. Hierarchical clustering of principal components was applied to data collected from study participants.

Results

The relative abundance of Bifidobacterium in feces increased significantly after 3 weeks of daily consumption of both 1.3 g (p < 0.01) and 2.0 g GOS (p < 0.01). This was accompanied by a significant shift in the overall microbiota composition for the dosage of 2.0 g GOS (p < 0.01). Participants that showed a larger increase in Bifidobacterium in the intervention period compared to the change in Bifidobacterium in the control period, defined as responders, showed a significant overall difference in initial fecal microbiota composition as compared to non-responders (p = 0.04) and a trend towards lower baseline levels of Bifidobacterium in responders (p = 0.10).

Conclusion

Daily consumption of a low dose of GOS can lead to an increase in the relative abundance of Bifidobacterium in feces of healthy women. Additionally, with 2.0 g GOS, the enrichment of Bifidobacterium is accompanied with a shift in the overall microbiota composition.Clinical trial registration: clinicaltrials.gov, identifier NCT05762965.

Exploring Therapeutic Advances: A Comprehensive Review of Intestinal Microbiota Modulators

The gut microbiota establishes a mutually beneficial relationship with the host starting from birth, impacting diverse metabolic and immunological processes. Dysbiosis, characterized by an imbalance of microorganisms, is linked to numerous medical conditions, including gastrointestinal disorders, cardiovascular diseases, and autoimmune disorders. This imbalance promotes the proliferation of toxin-producing bacteria, disrupts the host's equilibrium, and initiates inflammation. Genetic factors, dietary choices, and drug use can modify the gut microbiota. However, there is optimism. Several therapeutic approaches, such as probiotics, prebiotics, synbiotics, postbiotics, microbe-derived products, and microbial substrates, aim to alter the microbiome. This review thoroughly explores the therapeutic potential of these microbiota modulators, analysing recent studies to evaluate their efficacy and limitations. It underscores the promise of microbiota-based therapies for treating dysbiosis-related conditions. This article aims to ensure practitioners feel well-informed and up to date on the most influential methods in this evolving field by providing a comprehensive review of current research.

Leaky Gut Syndrome: Myths and Management

Leaky gut syndrome is a condition widely popularized in the lay literature, although it is not currently accepted as a formal medical diagnosis. Multiple gastrointestinal symptoms are ascribed to leaky gut syndrome, including diarrhea, bloating, distension, abdominal pain, and dyspeptic symptoms of early satiety, nausea, and postprandial fullness. The etiology and pathophysiology of leaky gut syndrome are multifactorial; a preceding gastrointestinal infection, inflammatory bowel disease, and certain medications may be relevant factors in some patients. The diagnosis of leaky gut syndrome is problematic. Although patients are frequently informed that the diagnosis can be readily made using results from blood work or stool studies, no validated test currently exists to make this diagnosis. Patients report a variety of myths about the etiology, diagnosis, and treatment of leaky gut syndrome, which can cause alarm and can frequently lead to expensive, unnecessary tests and unproven, sometimes dangerous treatments. This article reviews some of the most common myths about leaky gut syndrome and provides data from the scientific literature to correct these statements. Management strategies, based on data, are provided when available.

Effect of probiotics on pregnancy outcomes in gestational diabetes: systematic review and meta-analysis

OBJECTIVE

Gestational diabetes mellitus (GDM) is a prevalent complication during pregnancy associated with numerous adverse outcomes. There is emerging evidence suggesting the potential of probiotics as a therapeutic measure for GDM; however, existing studies have yielded contradictory results. This meta-analysis assessed the efficacy of probiotics on blood glucose management and pregnancy outcomes in patients with GDM.

METHODS

A comprehensive search of the PubMed, Embase, and Cochrane databases was conducted up to August 22, 2023, to identify relevant studies. The primary outcomes focused on fasting blood glucose (FBG), fasting serum insulin (FSI), homeostasis model assessment of insulin resistance (HOMA-IR), and quantitative insulin sensitivity check index (QUICKI). The secondary outcomes included various maternal and neonatal outcomes.

RESULTS

This meta-analysis included 15 randomized controlled trials (RCTs), encompassing 1006 patients with GDM. The results showed that, compared to a placebo, probiotics demonstrated a significant reduction in FBG (MD - 2.58, 95% CI - 4.38 to - 0.79, p < 0.01), FSI (MD - 2.29, 95% CI - 3.40 to - 1.18, p < 0.01), HOMA-IR (MD - 0.56, 95% CI - 0.81 to - 0.32, p < 0.01), and birth weight (MD - 101.20, 95% CI - 184.62 to - 17.77, p = 0.02). Furthermore, it resulted in fewer neonatal intensive care unit (NICU) admissions (RR 0.60, 95% CI 0.40-0.89, p = 0.01), instances of hyperbilirubinemia (RR 0.31, 95% CI 0.16-0.61, p < 0.01), and elevated QUICKI (MD 0.01, 95% CI 0.00-0.01, p < 0.01). No significant impact was observed in the other analyzed outcomes.

CONCLUSIONS

In conclusion, probiotics improve FBG, FSI, and HOMA-IR, and reduce the occurrence of neonatal hyperbilirubinemia, NICU admissions, and birth weight in the offspring of patients with GDM. However, the quality of the evidence, as per the GRADE approach, varies from high to low, necessitating further studies to consolidate these findings.

The Therapeutic Potential of the Specific Intestinal Microbiome (SIM) Diet on Metabolic Diseases

Exploring the intricate crosstalk between dietary prebiotics and the specific intestinal microbiome (SIM) is intriguing in explaining the mechanisms of current successful dietary interventions, including the Mediterranean diet and high-fiber diet. This knowledge forms a robust basis for developing a new natural food therapy. The SIM diet can be measured and evaluated to establish a reliable basis for the management of metabolic diseases, such as diabetes, metabolic (dysfunction)-associated fatty liver disease (MAFLD), obesity, and metabolic cardiovascular disease. This review aims to delve into the existing body of research to shed light on the promising developments of possible dietary prebiotics in this field and explore the implications for clinical practice. The exciting part is the crosstalk of diet, microbiota, and gut-organ interactions facilitated by producing short-chain fatty acids, bile acids, and subsequent metabolite production. These metabolic-related microorganisms include Butyricicoccus, Akkermansia, and Phascolarctobacterium. The SIM diet, rather than supplementation, holds the promise of significant health consequences via the prolonged reaction with the gut microbiome. Most importantly, the literature consistently reports no adverse effects, providing a strong foundation for the safety of this dietary therapy.

Evaluation of synbiotic combinations of commercial probiotic strains with different prebiotics in in vitro and ex vivo human gut microcosm model

Exploring probiotics for their crosstalk with the host microbiome through the fermentation of non-digestible dietary fibers (prebiotics) for their potential metabolic end-products, particularly short-chain fatty acids (SCFAs), is important for understanding the endogenous host-gut microbe interaction. This study was aimed at a systematic comparison of commercially available probiotics to understand their synergistic role with specific prebiotics in SCFAs production both in vitro and in the ex vivo gut microcosm model. Probiotic strains isolated from pharmacy products including Lactobacillus sporogenes (strain not labeled), Lactobacillus rhamnosus GG (ATCC53103), Streptococcus faecalis (T-110 JPC), Bacillus mesentericus (TO-AJPC), Bacillus clausii (SIN) and Saccharomyces boulardii (CNCM I-745) were assessed for their probiotic traits including survival, antibiotic susceptibility, and antibacterial activity against pathogenic strains. Our results showed that the microorganisms under study had strain-specific abilities to persist in human gastrointestinal conditions and varied anti-infective efficacy and antibiotic susceptibility. The probiotic strains displayed variation in the utilization of six different prebiotic substrates for their growth under aerobic and anaerobic conditions. Their prebiotic scores (PS) revealed which were the most suitable prebiotic carbohydrates for the growth of each strain and suggested xylooligosaccharide (XOS) was the poorest utilized among all. HPLC analysis revealed a versatile pattern of SCFAs produced as end-products of prebiotic fermentation by the strains which was influenced by growth conditions. Selected synbiotic (prebiotic and probiotic) combinations showing high PS and high total SCFAs production were tested in an ex vivo human gut microcosm model. Interestingly, significantly higher butyrate and propionate production was found only when synbiotics were applied as against when individual probiotic or prebiotics were applied alone. qRT-PCR analysis with specific primers showed that there was a significant increase in the abundance of lactobacilli and bifidobacteria with synbiotic blends compared to pre-, or probiotics alone. In conclusion, this work presents findings to suggest prebiotic combinations with different well-established probiotic strains that may be useful for developing effective synbiotic blends.

Hyperbaric oxygen therapy ameliorates intestinal and systematic inflammation by modulating dysbiosis of the gut microbiota in Crohn's disease

BACKGROUND

Dysbiosis of the gut microbiota is pivotal in Crohn's disease (CD) and modulated by host physiological conditions. Hyperbaric oxygen therapy (HBOT) is a promising treatment for CD that can regulate gut microbiota. The relationship between HBOT and the gut microbiota in CD remains unknown.

METHODS

CD patients were divided into an HBOT group (n = 10) and a control group (n = 10) in this open-label prospective interventional study. The fecal samples before and after HBOT were used for 16 S rRNA gene sequencing and fecal microbiota transplantation (FMT). A colitis mouse model was constructed using dextran sulfate sodium, and intestinal and systematic inflammation was evaluated. The safety and long-term effect of HBOT were observed.

RESULTS

HBOT significantly reduced the level of C-reactive protein (CRP) (80.79 ± 42.05 mg/L vs. 33.32 ± 18.31 mg/L, P = 0.004) and the Crohn's Disease Activity Index (CDAI) (274.87 ± 65.54 vs. 221.54 ± 41.89, P = 0.044). HBOT elevated the declined microbial diversity and ameliorated the altered composition of gut microbiota in patients with CD. The relative abundance of Escherichia decreased, and that of Bifidobacterium and Clostridium XIVa increased after HBOT. Mice receiving FMT from donors after HBOT had significantly less intestinal inflammation and serum CRP than the group before HBOT. HBOT was safe and well-tolerated by patients with CD. Combined with ustekinumab, more patients treated with HBOT achieved clinical response (30%vs.70%, P = 0.089) and remission (20%vs.50%, P = 0.160) at week 4.

CONCLUSIONS

HBOT modulates the dysbiosis of gut microbiota in CD and ameliorates intestinal and systematic inflammation. HBOT is a safe option for CD and exhibits a promising auxiliary effect to ustekinumab.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2200061193. Registered 15 June 2022, https://www.chictr.org.cn/showproj.html?proj=171605 .

Effects of Probiotics on Gut Microbiota: An Overview

The role of probiotics in regulating intestinal flora to enhance host immunity has recently received widespread attention. Altering the human gut microbiota may increase the predisposition to several disease phenotypes such as gut inflammation and metabolic disorders. The intestinal microbiota converts dietary nutrients into metabolites that serve as biologically active molecules in modulating regulatory functions in the host. Probiotics, which are active microorganisms, play a versatile role in restoring the composition of the gut microbiota, helping to improve host immunity and prevent intestinal disease phenotypes. This comprehensive review provides firsthand information on the gut microbiota and their influence on human health, the dietary effects of diet on the gut microbiota, and how probiotics alter the composition and function of the human gut microbiota, along with their corresponding effects on host immunity in building a healthy intestine. We also discuss the implications of probiotics in some of the most important human diseases. In summary, probiotics play a significant role in regulating the gut microbiota, boosting overall immunity, increasing the abundance of beneficial bacteria, and helping ameliorate the symptoms of multiple diseases.

Explorative Characterization of GI Complaints, General Physical and Mental Wellbeing, and Gut Microbiota in Trained Recreative and Competitive Athletes with or without Self-Reported Gastrointestinal Symptoms

The current state of the literature lacks a clear characterization of gastrointestinal (GI) symptoms, gut microbiota composition, and general physical and mental wellbeing in well-trained athletes. Therefore, this study aimed to characterize differences in self-reported symptoms, gut microbiota composition, and wellbeing (i.e., sleep quality, mood, and physical (PHQ) and mental wellbeing) between athletes with and without GI symptoms. In addition, we assessed the potential impact of a 3-week multi-ingredient fermented whey supplement in the GI complaints group, without a control group, on the gut microbiota and self-reported GI symptoms and wellbeing. A total of 50 athletes (24.7 ± 4.5 years) with GI issues (GI group at baseline, GI-B) and 21 athletes (25.4 ± 5.3 years) without GI issues (non-GI group, NGI) were included. At baseline, there was a significant difference in the total gastrointestinal symptom rating scale (GSRS) score (24.1 ± 8.48 vs. 30.3 ± 8.82, p = 0.008) and a trend difference in PHQ (33.9 ± 10.7 vs. 30.3 ± 8.82, p = 0.081), but no differences (p > 0.05) were seen for other outcomes, including gut microbiota metrics, between groups. After 3-week supplementation, the GI group (GI-S) showed increased Bifidobacterium relative abundance (p < 0.05), reported a lower number of severe GI complaints (from 72% to 54%, p < 0.001), and PHQ declined (p = 0.010). In conclusion, well-trained athletes with GI complaints reported more severe GI symptoms than an athletic reference group, without showing clear differences in wellbeing or microbiota composition. Future controlled research should further investigate the impact of such multi-ingredient supplements on GI complaints and the associated changes in gut health-related markers.

Identification of carbohydrate gene clusters obtained from in vitro fermentations as predictive biomarkers of prebiotic responses

BACKGROUND

Prebiotic fibers are non-digestible substrates that modulate the gut microbiome by promoting expansion of microbes having the genetic and physiological potential to utilize those molecules. Although several prebiotic substrates have been consistently shown to provide health benefits in human clinical trials, responder and non-responder phenotypes are often reported. These observations had led to interest in identifying, a priori, prebiotic responders and non-responders as a basis for personalized nutrition. In this study, we conducted in vitro fecal enrichments and applied shotgun metagenomics and machine learning tools to identify microbial gene signatures from adult subjects that could be used to predict prebiotic responders and non-responders.

RESULTS

Using short chain fatty acids as a targeted response, we identified genetic features, consisting of carbohydrate active enzymes, transcription factors and sugar transporters, from metagenomic sequencing of in vitro fermentations for three prebiotic substrates: xylooligosacharides, fructooligosacharides, and inulin. A machine learning approach was then used to select substrate-specific gene signatures as predictive features. These features were found to be predictive for XOS responders with respect to SCFA production in an in vivo trial.

CONCLUSIONS

Our results confirm the bifidogenic effect of commonly used prebiotic substrates along with inter-individual microbial responses towards these substrates. We successfully trained classifiers for the prediction of prebiotic responders towards XOS and inulin with robust accuracy (≥ AUC 0.9) and demonstrated its utility in a human feeding trial. Overall, the findings from this study highlight the practical implementation of pre-intervention targeted profiling of individual microbiomes to stratify responders and non-responders.

Probiotics, prebiotics, synbiotics and other microbiome-based innovative therapeutics to mitigate obesity and enhance longevity via the gut-brain axis

The global prevalence of obesity currently exceeds 1 billion people and is accompanied by an increase in the aging population. Obesity and aging share many hallmarks and are leading risk factors for cardiometabolic disease and premature death. Current anti-obesity and pro-longevity pharmacotherapies are limited by side effects, warranting the development of novel therapies. The gut microbiota plays a major role in human health and disease, with a dysbiotic composition evident in obese and aged individuals. The bidirectional communication system between the gut and the central nervous system, known as the gut-brain axis, may link obesity to unhealthy aging. Modulating the gut with microbiome-targeted therapies, such as biotics, is a novel strategy to treat and/or manage obesity and promote longevity. Biotics represent material derived from living or once-living organisms, many of which have therapeutic effects. Pre-, pro-, syn- and post-biotics may beneficially modulate gut microbial composition and function to improve obesity and the aging process. However, the investigation of biotics as next-generation therapeutics has only just begun. Further research is needed to identify therapeutic biotics and understand their mechanisms of action. Investigating the function of the gut-brain axis in obesity and aging may lead to novel therapeutic strategies for obese, aged and comorbid (e.g., sarcopenic obese) patient populations. This review discusses the interrelationship between obesity and aging, with a particular emphasis on the gut microbiome, and presents biotics as novel therapeutic agents for obesity, aging and related disease states.

Effect of inulin, galacto-oligosaccharides, and polyphenols on the gut microbiota, with a focus on Akkermansia muciniphila

Inulins, galacto-oligosaccharides (GOS) and polyphenols are considered to stimulate the growth of Akkermansia muciniphila (A. muciniphila) in the gut. We performed a meta-analysis of six microbiome studies (821 stool samples from 451 participants) to assess the effects of inulin, GOS, and polyphenols on the abundance of A. muciniphila in the gut. The intervention of GOS increased the relative abundance of A. muciniphila in healthy participants. Additionally, metabolic pathways associated with carbohydrate metabolism and short-chain fatty acid release were enriched following the GOS intervention. Furthermore, after the GOS intervention, the coexisting microbial communities of A. muciniphila, such as Eubacterium hallii and Bacteroides, exhibited an enhanced correlation with A. muciniphila. In conclusion, our findings suggest that GOS may promote the growth of A. muciniphila in the gut by modulating the gut microbiota composition.

Effects of dietary fibre on metabolic health and obesity

Obesity and metabolic syndrome represent a growing epidemic worldwide. Body weight is regulated through complex interactions between hormonal, neural and metabolic pathways and is influenced by numerous environmental factors. Imbalances between energy intake and expenditure can occur due to several factors, including alterations in eating behaviours, abnormal satiation and satiety, and low energy expenditure. The gut microbiota profoundly affects all aspects of energy homeostasis through diverse mechanisms involving effects on mucosal and systemic immune, hormonal and neural systems. The benefits of dietary fibre on metabolism and obesity have been demonstrated through mechanistic studies and clinical trials, but many questions remain as to how different fibres are best utilized in managing obesity. In this Review, we discuss the physiochemical properties of different fibres, current findings on how fibre and the gut microbiota interact to regulate body weight homeostasis, and knowledge gaps related to using dietary fibres as a complementary strategy. Precision medicine approaches that utilize baseline microbiota and clinical characteristics to predict individual responses to fibre supplementation represent a new paradigm with great potential to enhance weight management efficacy, but many challenges remain before these approaches can be fully implemented.