Formation of propionate and butyrate by the human colonic microbiota

Comparing Campylobacter jejuni to three other enteric pathogens in OligoMM12 mice reveals pathogen-specific host and microbiota responses

Campylobacter jejuni, non-typhoidal Salmonella spp., Listeria monocytogenes and enteropathogenic/enterohemorrhagic Escherichia coli (EPEC/EHEC) are leading causes of food-borne illness worldwide. Citrobacter rodentium has been used to model EPEC and EHEC infection in mice. The gut microbiome is well-known to affect gut colonization and host responses to many food-borne pathogens. Recent progress has established gnotobiotic mice as valuable models to study how microbiota affect the enteric infections by S. Typhimurium, C. rodentium and L. monocytogenes. However, for C. jejuni, we are still lacking a suitable gnotobiotic mouse model. Moreover, the limited comparability of data across laboratories is often negatively affected by variations between different research facilities or murine microbiotas. In this study, we applied the standardized gnotobiotic OligoMM12 microbiota mouse model and compared the infections in the same facility. We provide evidence of robust colonization and significant pathological changes in OligoMM12 mice following infection with these pathogens. Moreover, we offer insights into pathogen-specific host responses and metabolite signatures, highlighting the advantages of a standardized mouse model for direct comparisons of factors influencing the pathogenesis of major food-borne pathogens. Notably, we reveal for the first time that C. jejuni stably colonizes OligoMM12 mice, triggering inflammation. Additionally, our comparative approach successfully identifies pathogen-specific responses, including the detection of genes uniquely associated with C. jejuni infection in humans. These findings underscore the potential of the OligoMM12 model as a versatile tool for advancing our understanding of food-borne pathogen interactions.

Non-stochastic reassembly of a metabolically cohesive gut consortium shaped by N-acetyl-lactosamine-enriched fibers

Diet is one of the main factors shaping the human microbiome, yet our understanding of how specific dietary components influence microbial consortia assembly and subsequent stability in response to press disturbances - such as increasing resource availability (feeding rate) - is still incomplete. This study explores the reproducible re-assembly, metabolic interplay, and compositional stability within microbial consortia derived from pooled stool samples of three healthy infants. Using a single-step packed-bed reactor (PBR) system, we assessed the reassembly and metabolic output of consortia exposed to lactose, glucose, galacto-oligosaccharides (GOS), and humanized GOS (hGOS). Our findings reveal that complex carbohydrates, especially those containing low inclusion (~1.25 gL-1) components present in human milk, such as N-acetyl-lactosamine (LacNAc), promote taxonomic, and metabolic stability under varying feeding rates, as shown by diversity metrics and network analysis. Targeted metabolomics highlighted distinct metabolic responses to different carbohydrates: GOS was linked to increased lactate, lactose to propionate, sucrose to butyrate, and CO2, and the introduction of bile salts with GOS or hGOS resulted in butyrate reduction and increased hydrogen production. This study validates the use of single-step PBRs for reliably studying microbial consortium stability and functionality in response to nutritional press disturbances, offering insights into the dietary modulation of microbial consortia and their ecological dynamics.

Microbial succinate promotes the response to metformin by upregulating secretory immunoglobulin a in intestinal immunity

Metformin is the first-line pharmacotherapy for type 2 diabetes mellitus; however, many patients respond poorly to this drug in clinical practice. The potential involvement of microbiota-mediated intestinal immunity and related signals in metformin responsiveness has not been previously investigated. In this study, we successfully constructed a humanized mouse model by fecal transplantation of the gut microbiota from clinical metformin-treated - responders and non-responders, and reproduced the difference in clinical phenotypes of responsiveness to metformin. The abundance of Bacteroides thetaiotaomicron, considered a representative differential bacterium of metformin responsiveness, and the level of secretory immunoglobulin A (SIgA) in intestinal immunity increased significantly in responder recipient mice following metformin treatment. In contrast, no significant alterations in B. thetaiotaomicron and SIgA were observed in non-responder recipient mice. The study of IgA-/- mice confirmed that downregulated expression or deficiency of SIgA resulted in non-response to metformin, meaning that metformin was unable to improve dysfunctional glucose metabolism and reduce intestinal and adipose tissue inflammation, ultimately leading to systemic insulin resistance. Furthermore, supplementation with succinate, a microbial product of B. thetaiotaomicron, potentially reversed the non-response to metformin by inducing the production of SIgA. In conclusion, we demonstrated that upregulated SIgA, which could be regulated by succinate, was functionally involved in metformin response through its influence on immune cell-mediated inflammation and insulin resistance. Conversely, an inability to regulate SIgA may result in a lack of response to metformin.

Maltotriosyl-erythritol, a transglycosylation product of erythritol by Thermus sp. amylomaltase and its application to prebiotic

In this study, maltotriosyl-erythritol (EG3) was synthesized as a novel prebiotic candidate via transglycosylation using recombinant amylomaltase (AMase) from Thermus sp. Tapioca starch served as the glucosyl donor, and erythritol as the acceptor. High-performance liquid chromatography (HPLC) revealed an EG3 yield of 14.0 % with a concentration of 2.8 mg/mL. Mass spectrometry confirmed the molecular weight of EG3 as 608 Da, and its strucopture was verified by 1H and 13C NMR analysis. EG3 exhibited greater resistance to acid, heat, and digestive enzymes compared to erythritol glucosides (EG1-2) and significantly promoted the growth of Lactobacillus casei BCC36987. Fermentation of EG3 resulted in the highest levels of lactic acid and total short-chain fatty acids, which may contribute to reduced pH levels. These findings suggest that erythritol-receptor products formed via AMase-catalyzed reactions, particularly EG3, are promising prebiotic ingredients, with the prebiotic activity of erythritol derivatives being influenced by the length of the carbohydrate chain.

Konjac glucomannan-embedded corn starch-derived type 1 resistant starch: Physicochemical properties, in vitro digestibility and fermentation characteristics, and in vivo glucose response in mice

Type 1 resistant starch (RS1) was prepared by high-pressure homogenization of corn starch (CS) embedded with 0.1%, 0.3%, 0.5%, and 0.7% konjac glucomannan (KGM), followed by heat-moisture treatment (HMT) at 30% moisture content and 110 °C for 6 h. After embedding KGM and applying HMT, the gelatinization temperature of CS increased by 8.09 °C, and the resistant starch content of cooked CS increased from 8.46% to 28.05%. The addition of KGM enhanced the adhesiveness and hardness of CS while reducing its elasticity and chewiness. Rheological analysis revealed that KGM addition increased both the storage and loss moduli of CS, and the crystallinity of KGM-embedded CS decreased to 18.58%. Moreover, short-chain fatty acid production and the abundance of beneficial bacteria, including Lachnospiraceae, Prevotellaceae, Anaerostipes, and Weissella, were higher in the RS1 group compared to the high-amylose maize starch and fructooligosaccharide groups. In the in vivo digestibility experiment, the peak blood glucose level in the RS1 group (7.08 mmol/L) was significantly lower than that in the CS group (8.57 mmol/L). These findings highlight the potential of KGM-embedded CS-derived RS1 in improving postprandial blood glucose levels in individuals with type 2 diabetes and obesity.

Association Between the Gut Microbiota and Alzheimer's Disease: An Update on Signaling Pathways and Translational Therapeutics

Alzheimer's disease (AD) is a cognitive disease with high morbidity and mortality. In AD patients, the diversity of the gut microbiota is altered, which influences pathology through the gut-brain axis. Probiotic therapy alleviates pathological and psychological consequences by restoring the diversity of the gut microbial flora. This study addresses the role of altered gut microbiota in the progression of neuroinflammation, which is a major hallmark of AD. This process begins with the activation of glial cells, leading to the release of proinflammatory cytokines and the modulation of cholinergic anti-inflammatory pathways. Short-chain fatty acids, which are bacterial metabolites, provide neuroprotective effects and maintain blood‒brain barrier integrity. Furthermore, the gut microbiota stimulates oxidative stress and mitochondrial dysfunction, which promote AD progression. The signaling pathways involved in gut dysbiosis-mediated neuroinflammation-mediated promotion of AD include cGAS-STING, C/EBPβ/AEP, RAGE, TLR4 Myd88, and the NLRP3 inflammasome. Preclinical studies have shown that natural extracts such as Ganmaidazao extract, isoorentin, camelia oil, Sparassis crispa-1, and xanthocerasides improve gut health and can delay the worsening of AD. Clinical studies using probiotics such as Bifidobacterium spp., yeast beta-glucan, and drugs such as sodium oligomannate and rifaximine have shown improvements in gut health, resulting in the amelioration of AD symptoms. This study incorporates the most current research on the pathophysiology of AD involving the gut microbiota and highlights the knowledge gaps that need to be filled to develop potent therapeutics against AD.

Ginger Extract Improves Cognitive Dysfunction via Modulation of Gut Microbiota-Derived Short-Chain Fatty Acids in D-Galactose/Ovariectomy-Induced Alzheimer-Like Disease

Alzheimer's disease (AD) is the most common form of dementia with complex causes and limited treatment options. Recent research has suggested a connection between the progression of AD and the activity of gut microbiota. Ginger, a plant known for its anti-inflammatory, antioxidant, and neuroprotective properties, has gained attention as a potential treatment for alleviating AD symptoms. In this study, we induced an AD model in female rats through ovariectomy and D-galactose injection and then investigated the protective effects of oral administration of ginger ethanolic extract. We assessed changes in short-chain fatty acids (SCFAs), learning and memory abilities, neuroinflammatory markers in plasma, and the hippocampus, as well as histological changes in the intestine and hippocampus in sham-operated, diseased, and treatment groups. Oral administration of ginger ethanolic extract improved gut microbiota activity, increased SCFA levels, and enhanced the expression of tight junction proteins. Additionally, ginger extract reduced the concentrations of TNF-α and IL-1β in both plasma and the hippocampus. Furthermore, it significantly reduced cell death and amyloid plaque deposition in the hippocampal tissue. These physiological changes resulted in improved performance in learning and memory tasks in rats treated with ginger compared with the disease group. These findings provide compelling evidence for the beneficial effects of ginger on the gut-brain axis, leading to improvements in learning and memory through the reduction of neuroinflammation.

Correlation between the structures of natural polysaccharides and their properties in regulating gut microbiota: Current understanding and beyond

Natural polysaccharides have complex structural properties and a wide range of health-promoting effects. Accumulating evidence suggests that the effects are significantly mediated through fermentation by gut microbiota. In recent years, the relationship between the structures of natural polysaccharides and their properties in regulating gut microbiota has garnered significant research attention as researchers attempt to precisely understand the role of gut microbiota in the bioactivities of natural polysaccharides. Progress in this niche, however, remains limited. In this review, we first provide an overview of current research investigating this structure-property relationship. We then present a detailed correlation analysis between the structural characteristics of 159 purified natural polysaccharides and their effects on gut microbiota reported over the past two decades. The analysis revealed that diverse gut bacteria show specific correlations with the molecular weight, glycosidic linkages, and monosaccharide composition of natural polysaccharides. Multifaceted molecular mechanisms, including carbohydrate binding, enzymatic degradation, and cross-feeding, were proposed to be collectively involved in these correlations. Finally, we offer our perspective on future studies to further improve our understanding of the relationship between polysaccharide structure and gut microbiota regulation.

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.

When short-chain fatty acids meet type 2 diabetes mellitus: Revealing mechanisms, envisioning therapies

Evidence is accumulating that short-chain fatty acids (SCFAs) produced by the gut microbiota play pivotal roles in host metabolism. They contribute to the metabolic regulation and energy homeostasis of the host not only by preserving intestinal health and serving as energy substrates but also by entering the systemic circulation as signaling molecules, affecting the gut-brain axis and neuroendocrine-immune network. This review critically summarizes the current knowledge regarding the effects of SCFAs in the fine-tuning of the pathogenesis of type 2 diabetes mellitus (T2DM) and insulin resistance, with an emphasis on the complex relationships among diet, microbiota-derived metabolites, T2DM inflammation, glucose metabolism, and the underlying mechanisms involved. We hold an optimistic view that elucidating how diet can influence gut bacterial composition and activity, SCFA production, and metabolic functions in the host will advance our understanding of the mutual interactions of the intestinal microbiota with other metabolically active organs, and may pave the way for harnessing these pathways to develop novel personalized therapeutics for glucometabolic disorders.

Interactions of non-starch polysaccharides with the gut microbiota and the effect of non-starch polysaccharides with different structures on the metabolism of the gut microbiota: A review

Humans consume large amounts of non-starch polysaccharides(NPs) daily. Some NPs, not absorbed by the body, proceed to the intestines. An increasing number of studies reveal a close relationship between NPs and gut microbiota(GM) that impact the human body. This review not only describes in detail the structures of several common NPs and their effects on GM, but also elucidates the degradation mechanisms of NPs in the intestine. The purpose of this review is to elucidate how NPs interact with GM in the intestine, which can provide valuable information for further studies of NPs.

Gut microbiota modulation and inflammation mitigation in a murine model through a hull-less and purple grain barley genotype

Barley, increasingly recognized for its health benefits, contains bioactive compounds like beta-glucans and (poly)phenols. Newly developed purple barley varieties, enriched with anthocyanins, offer potential gut health benefits. This study examined the effects of a hull-less, purple-grain barley genotype, consumed as whole-grain or isolated fractions (bran and endosperm), on gut microbiota and inflammation in a murine model. Fifty male and female BALB/cB&J mice were assigned to five diets over six weeks: standard diet (SD), rice diet (RD), whole-grain barley (WGB), anthocyanin-rich barley bran (BB), and beta-glucan-rich endosperm (PG). The BB diet triggered anti-inflammatory signals as it reduced IFN-γ and IL-4 in females, lowered TNF-α in both sexes, and decreased C-Reactive Protein (CRP) in males compared to SD. The PG diet improved gut barrier integrity by lowering LPS-binding protein levels. Barley-based diets enhanced gut microbiota diversity, particularly, by increasing beneficial bacteria like Lactobacillus, Lachnospiraceae UCG-001, and Akkermansia. Notably, BB and PG elicited stronger effects than WGB, suggesting that grain fractionation modifies the food matrix, potentially enhancing the bioaccessibility and bioavailability of key bioactive compounds. These results underscore the benefits of purple barley-derived fractions in promoting gut health and reducing inflammation, supporting their potential role to protect against inflammation-related conditions.

Effects of drinking water fructo-oligosaccharide supplementation on broiler chicken growth performance, blood glucose level, white blood cell count, carcass yield, meat quality, and cecal microbiota

This study investigated the effects of fructo-oligosaccharides (FOS) supplementation on the growth performance, blood glucose level, white blood cell count, carcass yield, meat quality, and cecal microbiota of Ross 308 broiler chickens. A completely randomized design was employed; FOS was supplemented in the drinking water at concentrations of 0 %, 0.25 %, and 0.50 %. From 11 to 24 d of age, 0.25 % FOS supplementation significantly increased feed intake (FI), while feed cost per gain (FCG) was significantly reduced at 0.50 % FOS (P < 0.05). During the overall period (1-36 d of age), FOS supplementation significantly improved the European Production Efficiency Factor (EPEF) (P < 0.01), and slowed down the reduction in blood glucose levels after the re-feeding period (2, 3, 4, and 5 h) (P < 0.01). Furthermore, FOS supplementation decreased the heterophil/lymphocyte (H:L) ratio (P < 0.05). However, it had no significant effect on breast meat yield or abdominal fat, but 0.50 % FOS supplementation tended to increase the percentage of cecal weight (P = 0.08). Supplementation with FOS (0.25 % and 0.50 %) significantly reduced breast meat cooking loss (P < 0.05). Regarding cecal microbiota, the FOS-supplemented groups showed increased abundances of Lactobacillaceae and Acidaminococcaceae, whereas the abundances of Lachnospiraceae and Barnesiellaceae were reduced (P < 0.05). In conclusion, drinking water FOS supplementation had a beneficial effect on the overall productive performance and cooking loss of broiler chickens via stress reduction, which may involve an improvement in the gut microbiota.

Nutraceutical Blends Promote Weight Loss, Inflammation Reduction, and Better Sleep: The Role of Faecalibacterium prausnitzii in Overweight Adults-A Double-Blind Trial

This study explores the effects of a nutraceutical blend with prebiotics, β-glucans, essential minerals, and silymarin on gut microbiota, inflammation, and sleep quality in obesity through microbiota reshaping and metabolic improvements over 90 days. A double-blind, randomized trial was conducted on 77 participants divided into two groups receiving either a standard nutraceutical blend (NSupple) or a silymarin-enriched blend (NSupple_Silybum). Fecal and plasma samples were collected at baseline and post-supplementation for gut microbiota, metabolic, and inflammatory marker analysis. The results showed a reduction in body weight, waist-to-height ratio, total cholesterol, and fractions in the NSupple_Silybum group. There was a dysbiosis recovery shown by the increase in beneficial gut bacteria, such as Lentisphaerae phylum, Lactobacillus and Faecalibacterium genera, and Faecalibacterium prausnitzii in the NSupple group, with a concurrent reduction in Adlercreutzia and Sutterella in the NSupple_Silybum group. Both groups demonstrated improved inflammatory profiles by the reduced TNF-α/IL-10 ratio, reduced cortisol levels, and reduced Firmicutes/Bacteroides ratio. Additionally, improvements in sleep quality were associated with reductions in pro-inflammatory cytokines and improved microbiota composition. The nutraceutical blend reshaped gut microbiota, enhanced anti-inflammatory species, and improved metabolic and sleep parameters, highlighting its potential as a nutritional strategy for managing obesity and reducing inflammation.

Select microbial metabolites in the small intestinal lumen regulates vagal activity via receptor-mediated signaling

The vagus nerve is proposed to enable communication between the gut microbiome and the brain, but activity-based evidence is lacking. We find that mice reared germ-free exhibit decreased vagal tone relative to colonized controls, which is reversed via microbiota restoration. Perfusing antibiotics into the small intestines of conventional mice, but not germ-free mice, acutely decreases vagal activity which is restored upon re-perfusion with intestinal filtrates from conventional, but not germ-free, mice. Microbiome-dependent short-chain fatty acids, bile acids, and 3-indoxyl sulfate indirectly stimulate vagal activity in a receptor-dependent manner. Serial perfusion of each metabolite class activates both shared and distinct neuronal subsets with varied response kinetics. Metabolite-induced and receptor-dependent increases in vagal activity correspond with the activation of brainstem neurons. Results from this study reveal that the gut microbiome regulates select metabolites in the intestinal lumen that differentially activate vagal afferent neurons, thereby enabling the microbial modulation of chemosensory signals for gut-brain communication.

Short-chain fatty acids in Huntington's disease: Mechanisms of action and their therapeutic implications

Huntington's disease (HD) is a progressive neurodegenerative disorder characterized by motor dysfunction, cognitive decline, and emotional instability, primarily resulting from the abnormal accumulation of mutant huntingtin protein. Growing research highlights the role of intestinal microbiota and their metabolites, particularly short-chain fatty acids (SCFAs), in modulating HD progression. SCFAs, including acetate, propionate, and butyrate, are produced by gut bacteria through dietary fiber fermentation and are recognized for their neuroprotective properties. Evidence suggests that SCFAs regulate neuroinflammation, neuronal communication, and metabolic functions within the central nervous system (CNS). In HD, these compounds may support neuronal health, reduce oxidative stress, and enhance blood-brain barrier (BBB) integrity. Their mechanisms of action involve binding to G-protein-coupled receptors (GPCRs) and modulating gene expression through epigenetic pathways, underscoring their therapeutic potential. This analysis examines the significance of SCFAs in HD, emphasizing the gut-brain axis and the benefits of dietary interventions aimed at modifying gut microbiota composition and promoting SCFA production. Further research into these pathways may pave the way for novel HD management strategies and improved therapeutic outcomes.

Microbial Guardians or Foes? Metagenomics Reveal Association of Gut Microbiota in Intestinal Toxicity Caused by DON in Mice

The role of gut microbiota has become a research hotspot in recent years; however, whether the gut microbiota are involved in the alleviation or exacerbation of Deoxynivalenol (DON) toxicity has not been fully studied. Therefore, the objective of this study was to investigate whether the gut microbiota are involved in reducing or aggravating the intestinal damage induced by DON in mice. Mice that received or did not receive antibiotic-induced intestinal flora clearance were orally given DON (5 mg kg/bw/day) for 14 days. At the end of the experiment, serum, intestinal tissue samples and colon contents were collected for further analysis. DON caused development of severe histopathological damage, such as necrosis and inflammation of the jejunum and colon in mice without gut microbiota clearance. The levels of tight junction proteins ZO-1 and occludin were reduced in the jejunum and colon of mice without gut microbiota clearance. In addition, the mRNA and protein levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) were increased in mice without gut microbiota clearance. The presence of microbiota exacerbate the intestinal damage induced by DON via changes in gut microbiota abundance and production of gut damaging metabolites.

The impact of gut microbiota on the occurrence, treatment, and prognosis of ischemic stroke

Ischemic stroke (IS) is a cerebrovascular disease that predominantly affects middle-aged and elderly populations, exhibiting high mortality and disability rates. At present, the incidence of IS is increasing annually, with a notable trend towards younger affected individuals. Recent discoveries concerning the "gut-brain axis" have established a connection between the gut and the brain. Numerous studies have revealed that intestinal microbes play a crucial role in the onset, progression, and outcomes of IS. They are involved in the entire pathophysiological process of IS through mechanisms such as chronic inflammation, neural regulation, and metabolic processes. Although numerous studies have explored the relationship between IS and intestinal microbiota, comprehensive analyses of specific microbiota is relatively scarce. Therefore, this paper provides an overview of the typical changes in gut microbiota following IS and investigates the role of specific microorganisms in this context. Additionally, it presents a comprehensive analysis of post-stroke microbiological therapy and the relationship between IS and diet. The aim is to identify potential microbial targets for therapeutic intervention, as well as to highlight the benefits of microbiological therapies and the significance of dietary management. Overall, this paper seeks to provide key strategies for the treatment and management of IS, advocating for healthy diets and health programs for individuals. Meanwhile, it may offer a new perspective on the future interdisciplinary development of neurology, microbiology and nutrition.

BNT162b2 mRNA vaccination affects the gut microbiome composition of patients with follicular lymphoma and chronic lymphocytic leukemia

BACKGROUND

In both chronic lymphatic leukemia (CLL) and follicular lymphoma (FL) immunotherapy determines B-depletion that leads to temporary suppression of humoral immunity, which is clinically relevant especially during the COVID-19 pandemic, when most patients in the first wave received the BNT162b2 vaccine during anti-neoplastic treatment.

METHODS

To capture changes in the immunome and microbiome composition in CLL and FL patients upon mRNA-based vaccination, we designed a prospective, longitudinal study to profile both the humoral and the cellular response after exposure to the BNT162b2 COVID-19 vaccine.

RESULTS

In both CLL patients and FL patients, the second and third administrations of the BNT162b2 vaccine increased the titer of specific antibodies against SARS-CoV-2. In FL patients, vaccination induced expansion of central memory CD8 + CD57dim CD279 + T cells and reduction of the neutrophil subset myeloid 1 (CD14-CD15+CD16dimCD64+CD33-CD38+PDL1+HLA-DR-); in both cohorts, CD45RA + CD27 + CD279 + NK cells were expanded after a full cycle of vaccination. After vaccination, the genera Collinsella, Gemmiger, Lachnospiraceae, Blautia, Ruminococcus and Lactobacillus increased in both CLL patients and FL patients, whereas Faecalibacterium, Enterobacteriacae, and Enterococcus decreased. Multivariate analysis failed to identify factors associated with changes in microbiome communities among the CLL and FL cohorts, considering age, sex, exposure to anti-CD20 therapy and disease activity. Only in FL patients, alpha diversity was negatively correlated with neutrophil subsets myeloid 1 e 5 at baseline and positively correlated with neutrophil subset 6 after vaccination. PICRUSt2 analysis showed how microbiome can also affect the host health promoting chronic inflammation. The L-lysine biosynthesis pathway was more represented in CLL patients, whereas the L-valine degradation pathway and the anaerobic degradation of purine nucleobases were overrepresented in the FL cohort.

CONCLUSIONS

Taken together, our findings reveal the effect of the BNT162b2 vaccine in shaping the microbiome composition in CLL and FL patients, despite receiving treatment for their underlying active disease, and highlight the importance of a comprehensive analysis of the immunome and microbiome profiling to understand immune function in these cohorts of patients.

CD8 + T cells may mediate the effect of gut microbiota on psoriasis: evidence from two-step mendelian randomization and bayesian weighting

Emerging research indicates that gut microbiota and the associated immune responses are crucial in the development of chronic inflammatory skin diseases. This investigation employs Mendelian Randomization (MR) and Bayesian weighting to elucidate the causal links between gut microbiota, immune cells, and psoriasis, with a specific emphasis on CD8 + T cells. We leveraged summary statistics from genome-wide association studies (GWAS) related to gut microbiota, immune cells, and psoriasis. Single nucleotide polymorphisms (SNPs) were chosen as instrumental variables (IVs) to evaluate causal relationships through various MR methods, such as inverse variance weighted (IVW), MR Egger, weighted median, and simple mode. Additionally, Bayesian weighting was used to validate results and account for potential pleiotropy. The IVW analysis revealed significant associations between certain gut microbiota and psoriasis, notably identifying a protective link between Escherichia coli and psoriasis. Further MR analysis demonstrated that Escherichia coli had a causal relationship with CD8 + T cells. Increased levels of CD8 + T cells were associated with a higher risk of psoriasis. BWMR analysis confirmed these findings, showing that CD8 + T cells mediated 10.09% of the protective effect of Escherichia coli on psoriasis. This study underscores the significant role of Escherichia coli and CD8 + T cells in psoriasis, suggesting both protective and exacerbating effects. Understanding these microbiota-immune interactions can lead to the development of more effective, personalized treatments and preventative strategies, ultimately improving patient outcomes and quality of life.

Maternal immunoglobulins differentially bind a diverse bacterial community in human colostrum and the stool of breastfed neonates

In the early days, maternal immunoglobulins are essential for sustaining a balanced gut environment by influencing the interaction between the host and the microbiome. The successional establishment of the pioneer strains is an interesting topic of research where maternal immunoglobulins appear to be important. This proof-of-concept study explored the binding pattern of IgA1, IgA2, IgM, and IgG classes to a commensal bacterial in human colostrum and the stool of breastfed neonates. We used flow cytometry coupled with 16S rRNA gene sequencing in human colostrum and neonatal feces samples to characterize this Ig-microbiota association. We observed that in human colostrum samples, IgA2 and IgM bind alfa and beta Proteobacteria, which can potentially stimulate neonatal immune system development in the gut. Other immunoglobulins like IgG predominantly bind facultative anaerobes belonging to the Firmicutes phylum, reported as part of human milk microbiota and pioneer colonizers of the neonatal gut. Maternal immunoglobulins also bind a wide diversity of bacteria in the neonatal stool. For instance, IgA2 and IgM bound more members of the phylum Bacteroidetes in comparison to IgG, these Bacteroidetes and some firmicutes have been reported as late colonizers of the neonatal gut, and their presence is important due to their ability to produce important short chain fatty acids like propionate and butyrate. Our results support the current view that microbial and immunoglobulin transference is crucial for developing the neonate's immune system and individual gut microbiota.

The Effects of Tea Polyphenols in Feed on the Immunity, Antioxidant Capacity, and Gut Microbiota of Weaned Goat Kids

In this present study, we aimed to investigate the effects of adding tea polyphenols to feed on the immunity, antioxidant capacity, and gut microbiota of weaned goat kids. Thirty weaned kids (Leizhou goats, average initial weight of 9.32 ± 1.72 kg, 2 months old) were randomly divided into five groups with six kids in each group, with half being male and half being female. The control (CON) group was fed the basal diet, and the four other groups were supplemented with 2, 4, or 6 g/kg tea polyphenols or 50 mg/kg chlortetracycline in the basal diet (denoted as the T1, T2, T3, and CTC groups, respectively). The results showed that compared to the CON and CTC groups, adding 4 or 6 g/kg tea polyphenols could increase the expression levels of serum antioxidant enzymes and intestinal antioxidant genes in the kids. It also increased the expression of Nrf2 and IL-10 in the intestine, while reducing the content and gene expression of cytokines (IL-1β, IL-6, IFN-γ, and TNF-α). Dietary supplementation with 4 or 6 g/kg tea polyphenols reduced the expression levels of TLR4, MyD88, and NFκB in intestinal tissue, activated intestinal protective mechanisms, and enhanced the immune defense of the intestinal epithelium. Compared to the CTC group, feeding tea polyphenols significantly increased the Simpson indices. However, adding 4 g/kg tea polyphenols significantly increased the relative abundance of Verrucomicrobiota, Candidatus Soleaferrea, the Christensenellaceae R-7 group, and Prevotella, as well as the acetic acid content in the cecum of the kids (p < 0.05). Overall, the results indicate that dietary supplementation with 4 g/kg of tea polyphenols can effectively maintain the homeostasis of the gut microbiota and enhance the anti-inflammatory and antioxidant capabilities of weaned kids.

Forsythia suspensa leaf fermented tea extracts attenuated oxidative stress in mice via the Ref-1/HIF-1α signal pathway and modulation of gut microbiota

Forsythia suspensa leaf fermented tea (FSLFT) is made from tender buds of Forsythia suspensa collected in spring. The main active components of FSLFT include forsythiaside, forsythia ester glycoside, rutin, and forsythia flavonoids, which have antibacterial, antioxidant, liver-protective, and immune-regulatory effects. Oxidative stress can trigger excessive apoptosis in intestinal epithelial cells, leading to dysfunction of the small intestinal mucosa and impaired intestinal absorption. This study focused on Kunming mice as research subjects and used hydrogen peroxide as an inducer to investigate the antioxidant and anti-inflammatory effects of FSLFT in vivo, as well as its regulatory effects on the intestinal microbiota of mice. The aim of this study was to establish a theoretical foundation for the functional study of Forsythia suspensa leaves and provide specific recommendations for their growth and application. The results showed that H2O2 treatment led to an increase in oxidative levels in mice. FSLFT has been shown to have antioxidant effects via the Redox Factor-1(Ref-1)/ hypoxia-inducible factor-1 alpha (HIF-1α) pathway, reduce inflammation caused by hydrogen peroxide through the Toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) signaling pathway, and protect mouse colons from oxidative stress by repairing gut microbiota imbalance and increasing microbial diversity and abundance. These findings establish a theoretical basis for studying the functional properties of FSLFT.

Chickpea-resistant starch exhibits bioactive function for alleviating atopic dermatitis via regulating butyrate production

Resistant starch (RS) is one of the bioactive polysaccharides to produce Short-chain fatty acids (SCFAs) in the colon and contributes to allergic diseases including atopic dermatitis (AD). However, the bioactive mechanism of RS relieving AD needs to be elucidated. In this study, RS was prepared using chickpeas. Its microstructure and crystal structure were thoroughly characterized. Chickpea RS significantly improved the clinical symptoms and restored Th1/Th2 immune balance in mice with AD induced by calcipotriol. These benefits were eliminated by antibiotic cocktail treatment, suggesting that gut microbiota mediated the alleviation effects of chickpea RS on AD. Based on metagenomic sequencing and untargeted metabolomic analysis, chickpea RS treatment significantly increased the proportions of Butyricimonas virosa, Bifidobacterium pseudolongum, and Faecalibaculum rodentium, and a total of 206 differential metabolites were altered, especially the increase in propionate and butyrate production. Furthermore, we found that acylated butyrate, but not propionate, improved the pathological characteristics by activating GPR109A, which inhibit the phosphorylation levels of IκB-α, p50, p65, JNK, and p-JNK. Collectively, chickpea RS exhibited the bioactive function for regulating the communication of the gut-skin axis via regulating butyrate production to activate GPR109A.

Distinct Gut Microbiota Profiles in Normal Weight Obesity and Their Association With Cardiometabolic Diseases: Results From Two Independent Cohort Studies

BACKGROUND

Normal weight obesity (NWO) is characterized by excess body fat in individuals with normal body mass index (BMI). This study aimed to investigate gut microbiota alterations in NWO and their potential associations with cardiometabolic diseases (CMD) risk in two independent cohorts.

METHODS

Our NWO-CMD mortality analysis included 168 099 adults with normal BMI from two large open-access databases, while our NWO-gut microbiota study involved 5467 adults with normal BMI from two independent cohorts: the WELL-China cohort and the Lanxi cohort. NWO was defined as having a normal BMI (18.5-23.9 kg/m2) but an excess per cent body fat (PBF, ≥ 25% in men and ≥ 35% in women). Normal weight lean was defined as having a normal BMI and normal PBF. The 16S rRNA gene sequencing method was used to analyse gut microbiota data.

RESULTS

The study comprised 3620 (64.0% female, median age 58 years) and 1847 (64.3% female, median age 56 years) participants from the WELL-China and Lanxi cohorts. In our meta-analysis, NWO is associated with 26% (95% CI: 1.07-1.41) higher risk of CMD mortality. Gut microbial analyses indicated that the NWO group exhibited reduced levels of observed species (p = 0.009 and p = 0.013) and Chao 1 index (p = 0.002 and p = 0.002) and altered gut microbial compositions (p = 0.009 and p < 0.001) compared with the NWL group. Seven genera were consistently observed to be associated with NWO in both two cohorts (all Q < 0.25). Among them, five (Fusobacterium, Ruminococcus gnavus group, Ruminococcus torques group, Coprococcus and Christensenellaceae_R7_group) have been previously linked to obesity, while the other two (Phascolarctobacterium and Clostridia_UCG-014) were minimally reported. We also found statistically significant differences in the microbial composition between the NWO group and the obesity group (p = 0.001 and p = 0.001). Furthermore, the NWO-related gut microbiome was associated with an elevated risk of hypertension, dyslipidaemia and metabolic syndrome, the corresponding HR (95% CIs) were 1.11 (1.01-1.22), 1.19 (1.10-1.29) and 1.17 (1.05-1.30) in the WELL-China cohort and 1.14 (1.02-1.27), 1.15 (1.02-1.29) and 1.16 (1.02-1.32) in the Lanxi cohort.

CONCLUSIONS

These two large cohorts provided reliable evidence that gut microbiota alterations in NWO resemble those found in obesity, yet also display unique aspects. This distinct microbiota profile may contribute to heightened cardiometabolic risks in adults with normal BMI.

Functional foods acting on gut microbiota-related wellness: The multi-unit in vitro colon model to assess gut ecological and functional modulation

The aim of this study was to investigate the effect of a functional probiotic cheese (FPC) on gut microbiota (GM), after simulated digestion performed by a multi-unit in vitro colon model (MICODE). Squacquerone-like cheese was produced using the starter Streptococcus thermophilus (control, CTRL), and supplemented with the probiotic Lacticaseibacillus rhamnosus, which was either subjected to high pressure homogenization (LrH) or not (Lr). Samples were stratified by cheese type, storage time, and colonic fermentation phase. Samples were then digested with MICODE and digests were characterized for ecological and functional profiles. The lactobacilli detected in Lr and LrH cheeses (9.0 log CFU/g) were represented by the probiotic strain L. rhamnosus and remained unchanged after storage at 4 °C. Lactobacilli levels in CTRLs increased from 1.5 log CFU/g to 2.0 log CFU/g after six days at 4 °C, while total coliforms remained below 1.5 log CFU/g in all samples. Real-time qPCR indicated a positive GM response after FPC simulated digestion, highlighting an abundance of bifidobacteria, lactobacilli and Clostridium group IV in LrH samples. Metataxonomy revealed higher levels of Firmicutes and Proteobacteria (p ≤ 0.05) after simulated digestion, as well as Megasphaera, Escherichia, Prevotella and Dorea. Moreover, an increase of short and medium chain fatty acids were detected by metabolomics. Overexpression of inferred KEGG metabolic pathways showed mainly fatty acids, novobiocin and amino acid metabolism. Understanding how functional foods can modify the GM may lead to the development of targeted microbiome-based therapies and the exploitation of these foods for the benefit of human health.

Polyphenols synergistic drugs to ameliorate non-alcoholic fatty liver disease via signal pathway and gut microbiota: A review

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease with an increasing incidence worldwide. Single drug therapy may have toxic side effects and disrupt gut microbiota balance. Polyphenols are widely used in disease intervention due to their distinctive nutritional properties and medicinal value, which a potential gut microbiota modulator. However, there is a lack of comprehensive review to explore the efficacy and mechanism of combined therapy with drugs and polyphenols for NAFLD.

AIM OF REVIEW

Based on this, this review firstly discusses the link between NAFLD and gut microbiota, and outlines the effects of polyphenols and drugs on gut microbiota. Secondly, it examined recent advances in the treatment and intervention of NAFLD with drugs and polyphenols and the therapeutic effect of the combination of the two. Finally, we highlight the underlying mechanisms of polyphenol combined drug therapy in NAFLD. This is mainly in terms of signaling pathways (NF-κB, AMPK, Nrf2, JAK/STAT, PPAR, SREBP-1c, PI3K/Akt and TLR) and gut microbiota. Furthermore, some emerging mechanisms such as microRNA potential biomarker therapies may provide therapeutic avenues for NAFLD.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Drawing inspiration from combination drug strategies, the use of active substances in combination with drugs for NAFLD intervention holds transformative and prospective potential, both improve NAFLD and restore gut microbiota balance while reducing the required drug dosage. This review systematically discusses the bidirectional interactions between gut microbiota and NAFLD, and summarizes the potential mechanisms of polyphenol synergistic drugs in the treatment of NAFLD by modulating signaling pathways and gut microbiota. Future researches should develop multi-omics technology to identify patients who benefit from polyphenols combination drugs and devising individualized treatment plans to enhance its therapeutic effect.

Resveratrol: A Narrative Review Regarding Its Mechanisms in Mitigating Obesity-Associated Metabolic Disorders

Resveratrol (RSV) is a naturally occurring astragalus-like polyphenolic compound with remarkable weight loss properties. However, the mechanism of RSV in treating obesity is unclear. In this narrative review, we explored electronic databases (PubMed) for research articles from 2021 to the present using the keywords "resveratrol" and "obesity". This article explores the mechanisms involved in the alleviation of obesity-related metabolic disorders by RSV. RSV affects obesity by modulating mitochondrial function, insulin signaling, and gut microbiota, regulating lipid metabolism, inhibiting oxidative stress, and regulating epigenetic regulation. Administering RSV to pregnant animals exhibits maternal and first-generation offspring benefits, and RSV administration to lactating animals has long-term benefits, which involve the epigenetic modulations by RSV. A comprehensive understanding of the epigenetic mechanisms of RSV regulation could help in developing drugs suitable for pregnancy preparation groups, pregnant women, and nursing infants.

Synergistic interactions between gut microbiota and short chain fatty acids: Pioneering therapeutic frontiers in chronic disease management

Microorganisms in the gut play a pivotal role in human health, influencing various pathophysiological processes. Certain microorganisms are particularly essential for maintaining intestinal homeostasis, reducing inflammation, supporting nervous system function, and regulating metabolic processes. Short-chain fatty acids (SCFAs) are a subset of fatty acids produced by the gut microbiota (GM) during the fermentation of indigestible polysaccharides. The interaction between GM and SCFAs is inherently bidirectional: the GM not only shapes SCFAs composition and metabolism but SCFAs also modulate microbiota's diversity, stability, growth, proliferation, and metabolism. Recent research has shown that GM and SCFAs communicate through various pathways, mainly involving mechanisms related to inflammation and immune responses, intestinal barrier function, the gut-brain axis, and metabolic regulation. An imbalance in GM and SCFA homeostasis can lead to the development of several chronic diseases, including inflammatory bowel disease, colorectal cancer, systemic lupus erythematosus, Alzheimer's disease, and type 2 diabetes mellitus. This review explores the synergistic interactions between GM and SCFAs, and how these interactions directly or indirectly influence the onset and progression of various diseases through the regulation of the mechanisms mentioned above.

Artificial sweeteners and Type 2 Diabetes Mellitus: A review of current developments and future research directions

While artificial sweeteners are Generally Regarded as Safe (GRAS), the scientific community remains divided on their safety status. The previous assumption that artificial sweeteners are inert within the body is no longer valid. Artificial sweeteners, known for their high intense sweetness and low or zero calories, are extensively used today in food and beverage products as sugar substitutes and are sometimes recommended for weight management and Type 2 Diabetes Mellitus (T2DM) patients. The general omission of information about the concentration of artificial sweeteners on market product labels makes it challenging to determine the amounts of artificial sweeteners consumed by people. Despite regulatory authorization for their usage, such as from the United States Food and Drug Administration (FDA), concerns remain about their potential association with metabolic diseases, such as T2DM, which the artificial sweeteners were supposed to reduce. This review discusses the relationship between artificial sweetener consumption and the risk of developing T2DM. With the increasing number of recent scientific studies adding to the debate on this subject matter, we assessed recent literature and up-to-date evidence. Importantly, we highlight future research directions toward furthering knowledge in this field of study.

Role of gut microbiota and fecal metabolites in the protective effect of soybean pulp-rich diet against estrogen-induced cholestasis in rats

This study was designed to explore the role of gut microbiota and its metabolites in the treatment of estrogen-induced cholestasis (EIC) in rats with a soybean pulp-rich diet and to clarify the effects of daidzein (DAI), a principal active ingredient of soybean pulp. The findings demonstrated that the soybean pulp-rich diet could relieve cholestasis by decreasing the levels of total bile acids (TBA) and alkaline phosphatase and enhancing the bile flow rate. Through gut microbiota and metabolomics analyses, it was revealed that this diet might alter the abundances of certain bacterial taxa including Akkermansia, Bacteroides, and Turicibacter, thus influencing lipid metabolism, tryptophan metabolism, and steroid metabolism, which led to disparities between the groups fed with and without the soybean pulp-rich diet. Moreover, the soybean pulp-rich diet could modulate the abundances of Prevotella spp. and Tyzzerella, reducing EIC by regulating lipid metabolism and short-chain fatty acids synthesis. Notably, DAI treatment significantly alleviated the abnormalities in serum TBA, alanine aminotransferase, and aspartate aminotransferase levels and mitigated the liver tissue damage in the EIC model. In summary, during cholestasis, variations in gut microbiota and metabolite profiles occurred. The intervention of soybean pulp affected the abundances of bacteria (such as Prevotella spp. and Tyzzerella) and regulated lipid metabolism-related pathways. Importantly, DAI was identified as a crucial component for the protective effects associated with the soybean pulp diet.

Health Effects and Therapeutic Potential of the Gut Microbe Akkermansia muciniphila

Akkermansia muciniphila is a bacterium commonly found in the human gastrointestinal tract that has received considerable interest as a potential probiotic for the improvement of gut health and overall metabolic function. A. muciniphila is enriched in the mucus layer of the intestinal lining, where it degrades mucin and plays a significant role in gut barrier maintenance and immune regulation. A higher abundance of A. muciniphila has been observed in the gut of healthy individuals relative to those with metabolic disorders, and multiple metabolic benefits, including improved glucose management, reduced body fat, and reduced inflammation have been linked to A. muciniphila. Current research on A. muciniphila primarily relies on mouse models, with limited human interventional studies available. While these animal studies offer valuable insights into the potential roles of A. muciniphila in health and disease, further clinical investigations in humans are needed to fully understand its impact. Here, we explore the current scope of A. muciniphila research and its potential as a therapeutic agent to improve gut and metabolic health while also emphasizing the need to optimize techniques to further improve studies of this organism.

Short-Chain Fatty Acids: Promising Therapeutic Targets for Respiratory Syncytial Virus Infection

The intestinal microbiota is a complex community of organisms present in the human gastrointestinal tract, some of which can produce short-chain fatty acids (SCFAs) through the fermentation of dietary fiber. SCFAs play a major role in mediating the intestinal microbiota's regulation of host immunity and intestinal homeostasis. Respiratory syncytial virus (RSV) can cause an imbalance between anti-inflammatory and proinflammatory responses in the host. In addition, changes in SCFA levels and the structure of the intestinal microbiota have been observed after RSV infection. Therefore, there may be a link between SCFAs and RSV infection, and SCFAs are expected to be therapeutic targets for RSV infection.

Impact of Cooking Techniques on the Dietary Fiber Profile in Selected Cruciferous Vegetables

Cruciferous vegetables of the plant order Brassicales are an attractive dietary component and a valuable source of fiber. However, the nutritional-physiological properties are different when comparing soluble and insoluble fibers. Another significant impact is the transformation of fibers by different influencing factors during food preparation. Cruciferous vegetables, especially, are dominantly processed to soften the matrix. As a result, during cooking, the polysaccharides are dissolved, swelled, or degraded to a certain extent, influencing the composition and the nutritional-physiological properties. The aim of the present study was to analyze the impact of different cooking procedures on changes in the dietary fiber content profile of three different plants: white cauliflower (Brassica oleracea L. var. botrytis), broccoli (B. oleracea L. var. italica), and Brussels sprouts (B. oleracea L. var. gemmifera). The sample material was subjected to direct ("in the water") and steam cooking. The dietary fiber content and the content of its fractions were determined using an enzymatic analysis method. The results of the research show that the cooking process had a significant influence on the content of dietary fiber fractions in cruciferous vegetables. The concentration of insoluble dietary fiber decreased, whereas the content of soluble dietary fiber increased. When considering the average influence of each process, both steam cooking and direct cooking had a similar impact on changes in the concentrations of dietary fiber fractions. It can therefore be concluded that, when considering dietary fiber content, both processes can be equally well chosen as a thermal treatment for cruciferous vegetables.

Harnessing Gut Microbiota for Biomimetic Innovations in Health and Biotechnology

The gut microbiota is a complex and dynamic ecosystem that plays a fundamental role in human health by regulating immunity, metabolism, and the gut-brain axis. Beyond its critical physiological functions, it has emerged as a rich source of inspiration for biomimetic innovations in healthcare and biotechnology. This review explores the transformative potential of microbiota-based biomimetics, focusing on key biological mechanisms such as resilience, self-regulation, and quorum sensing. These mechanisms have inspired the development of innovative applications, including personalized probiotics, synbiotics, artificial microbiomes, bioinspired biosensors, and bioremediation systems. Such technologies aim to emulate and optimize the intricate functions of microbial ecosystems, addressing challenges in healthcare and environmental sustainability. The integration of advanced technologies, such as artificial intelligence, bioengineering, and multi-omics approaches, has further accelerated the potential of microbiota biomimetics. These tools enable the development of precision therapies tailored to individual microbiota profiles, enhance the efficacy of diagnostic systems, and facilitate the design of environmentally sustainable solutions, such as waste-to-energy systems and bioremediation platforms. Emerging areas of innovation, including gut-on-chip models and synthetic biology, offer unprecedented opportunities for studying and applying microbiota principles in controlled environments. Despite these advancements, challenges remain. The replication of microbial complexity in artificial environments, ethical concerns regarding genetically engineered microorganisms, and equitable access to advanced therapies are critical hurdles that must be addressed. This review underscores the importance of interdisciplinary collaboration and public awareness in overcoming these barriers and ensuring the responsible development of microbiota-based solutions. By leveraging the principles of microbial ecosystems, microbiota biomimetics represents a promising frontier in healthcare and sustainability. This approach has the potential to revolutionize therapeutic strategies, redefine diagnostic tools, and address global challenges, paving the way for a more personalized, efficient, and sustainable future in medicine and biotechnology.

Response of the gut microbiome and metabolome to dietary fiber in healthy dogs

Dietary fiber confers multiple health benefits originating from the expansion of beneficial gut microbial activity. However, very few studies have established the metabolic consequences of interactions among specific fibers, microbiome composition, and function in either human or representative animal models. In a study design reflective of realistic population dietary variation, fecal metagenomic and metabolomic profiles were analyzed from healthy dogs fed 12 test foods containing different fiber sources and quantities (5-13% as-fed basis). Taxa and functions were identified whose abundances were associated either with overall fiber intake or with specific fiber compositions. Fourteen microbial species were significantly enriched in response to ≥1 specific fiber source; enrichment of fiber-derived metabolites was more pronounced in response to these fiber sources. Positively associated fecal metabolites, including short-chain fatty acids, acylglycerols, fiber bound sugars, and polyphenols, co-occurred with microbes enriched in specific food groups. Critically, the specific metabolite pools responsive to differential fiber intake were dependent on differences both in individual microbial community membership and in overall ecological configuration. This helps to explain, for the first time, differences in microbiome-diet associations observed in companion animal epidemiology. Thus, our study corroborates findings in human cohorts and reinforces the role of personalized microbiomes even in seemingly phenotypically homogeneous subjects.

IMPORTANCE

Consumption of dietary fiber changes the composition of the gut microbiome and, to a larger extent, the associated metabolites. Production of health-relevant metabolites such as short-chain fatty acids from fiber depends both on the consumption of a specific fiber and on the enrichment of beneficial metabolite-producing species in response to it. Even in a seemingly homogeneous population, the benefit received from fiber consumption is personalized and emphasizes specific fiber-microbe-host interactions. These observations are relevant for both population-wide and personalized nutrition applications.

Core microbe Bifidobacterium in the hindgut of calves improves the growth phenotype of young hosts by regulating microbial functions and host metabolism

BACKGROUND

The growth and health of young ruminants are regulated by their gut microbiome, which can have lifelong consequences. Compared with subjective grouping, phenotypic clustering might be a more comprehensive approach to revealing the relationship between calf growth state and core gut microbes. However, the identification of beneficial gut bacteria and its internal mechanisms of shaping host phenotype differentiation remains unclear.

RESULTS

In this study, calves were divided into two clusters, cluster1 and cluster2, based on 29 phenotypic indicators using cluster analysis. Calves in cluster2 showed better growth performance, including higher body weight (BW), average daily gain (ADG), and dry matter intake (DMI), as well as better serum indicators with a high level of total superoxide dismutase (T-SOD), interleukin-6 (IL-6), and insulin-like growth factor-1 (IGF-1) compared to those in cluster1. Multi-omics was used to detect microbial features among calves in different phenotypic clusters. Distinct differences were observed between the two clustered gut microbiomes, including microbial diversity and composition. The close relationships between growth performance, blood metabolites, and microbiome were also confirmed. In cluster2, Bifidobacterium members were the dominant contributors to microbial metabolic functions with a higher abundance. Furthermore, pathways involved in carbohydrate degradation, glycolysis, and biosynthesis of propionate and proteins were active, while methane production was inhibited. In addition, the diversity and richness of hindgut resistome in cluster2 were lower than those in cluster1. The isolation and culture of Bifidobacterium strain, as well as the mice experiment, indicated that B. longum 1109 from calf feces in cluster2 could promote the growth of young hosts, enhance their blood immunity and antioxidation, and improve the development of hindgut.

CONCLUSIONS

In summary, cluster analysis has proved to be a feasible and reliable approach for identifying phenotypic subgroups of calves, prompting further exploration of host-microbiome interactions. Bifidobacterium as a core microbe in the hindgut of calves may play a crucial probiotic role in host phenotypic differentiation. This study enhances our comprehension of how gut core microbe shapes the host phenotype and provides new insights into the manipulation of beneficial gut colonizers to improve the growth performance and productivity of young ruminants. Video Abstract.

Unveiling the Interplay Between the Human Microbiome and Gastric Cancer: A Review of the Complex Relationships and Therapeutic Avenues

The human microbiota plays a crucial role in maintaining overall health and well-being. The gut microbiota has been implicated in developing and progressing various diseases, including cancer. This review highlights the related mechanisms and the compositions that influence cancer pathogenesis with a highlight on gastric cancer. We provide a comprehensive overview of the mechanisms by which the microbiome influences cancer development, progression, and response to treatment, with a focus on identifying potential biomarkers for early detection, prevention strategies, and novel therapeutic interventions that leverage microbiome modulation. This comprehensive review can guide future research and clinical practices in understanding and harnessing the microbiome to optimize gastric cancer therapies.

Understanding Patterns of the Gut Microbiome May Contribute to the Early Detection and Prevention of Type 2 Diabetes Mellitus: A Systematic Review

The rising burden of type 2 diabetes mellitus (T2DM) is a growing global public health problem, particularly prominent in developing countries. The early detection of T2DM and prediabetes is vital for reversing the outcome of disease, allowing early intervention. In the past decade, various microbiome-metabolome studies have attempted to address the question of whether there are any common microbial patterns that indicate either prediabetic or diabetic gut microbial signatures. Because current studies have a high methodological heterogeneity and risk of bias, we have selected studies that adhered to similar design and methodology. We performed a systematic review to assess if there were any common changes in microbiome belonging to diabetic, prediabetic and healthy individuals. The cross-sectional studies presented here collectively covered a population of 65,754 people, with 1800 in the 2TD group, 2770 in the prediabetic group and 61,184 in the control group. The overall microbial diversity scores were lower in the T2D and prediabetes cohorts in 86% of the analyzed studies. Re-programming of the microbiome is potentially one of the safest and long-lasting ways to eliminate diabetes in its early stages. The differences in the abundance of certain microbial species could serve as an early warning for a dysbiotic gut environment and could be easily modified before the onset of disease by changes in lifestyle, taking probiotics, introducing diet modifications or stimulating the vagal nerve. This review shows how metagenomic studies have and will continue to identify novel therapeutic targets (probiotics, prebiotics or targets for elimination from flora). This work clearly shows that gut microbiome intervention studies, if performed according to standard operating protocols using a predefined analytic framework (e.g., STORMS), could be combined with other similar studies, allowing broader conclusions from collating all global cohort studies efforts and eliminating the effect-size statistical insufficiency of a single study.

Antibiotic-mediated dysbiosis leads to activation of inflammatory pathways

Introduction

The gut microbiota plays a pivotal role in influencing host health, through the production of metabolites and other key signalling molecules. While the impact of specific metabolites or taxa on host cells is well-documented, the broader impact of a disrupted microbiota on immune homeostasis is less understood, which is particularly important in the context of the increasing overuse of antibiotics.

Methods

Female C57BL/6 mice were gavaged twice daily for four weeks with Vancomycin, Polymyxin B, or PBS (control). Caecal microbiota composition was assessed via 16S rRNA sequencing and caecal metabolites were quantified with NMR spectroscopy. Immune profiles of spleen and mesenteric lymph nodes (MLNs) were assessed by flow cytometry, and splenocytes assessed for ex vivo cytokine production. A generalised additive model approach was used to examine the relationship between global antibiotic consumption and IBD incidence.

Results

Antibiotics significantly altered gut microbiota composition, reducing alpha-diversity. Acetate and butyrate were significantly reduced in antibiotic groups, while propionate and succinate increased in Vancomycin and PmB-treated mice, respectively. The MLNs and spleen showed changes only to DC numbers. Splenocytes from antibiotic-treated mice stimulated ex vivo exhibited increased production of TNF. Epidemiological analysis revealed a positive correlation between global antibiotic consumption and IBD incidence.

Discussion

Our findings demonstrate that antibiotic-mediated dysbiosis results in significantly altered short-chain fatty acid levels but immune homeostasis in spleen and MLNs at steady state is mostly preserved. Non-specific activation of splenocytes ex vivo, however, revealed mice with perturbed microbiota had significantly elevated production of TNF. Thus, this highlights antibiotic-mediated disruption of the gut microbiota may program the host towards dysregulated immune responses, predisposing to the development of TNF-associated autoimmune or chronic inflammatory disease.

Roseburia intestinalis-derived butyrate alleviates neuropathic pain

Approximately 20% of patients with shingles develop postherpetic neuralgia (PHN). We investigated the role of gut microbiota in shingle- and PHN-related pain. Patients with shingles or PHN exhibited significant alterations in their gut microbiota with microbial markers predicting PHN development among patients with shingles. Functionally, fecal microbiota transplantation from patients with PHN to mice heightened pain sensitivity. Administration of Roseburia intestinalis, a bacterium both depleted in patients with shingles and PHN, alleviated peripheral nerve injury-induced pain in mice. R. intestinalis enhanced vagal neurotransmission to the nucleus tractus solitarius (NTS) to suppress the central amygdala (CeA), a brain region involved in pain perception. R. intestinalis-generated butyrate activated vagal neurons through the receptor, G protein-coupled receptor 41 (GPR41). Vagal knockout of Gpr41 abolished the effects of R. intestinalis on the NTS-CeA circuit and reduced pain behaviors. Overall, we established a microbiota-based model for PHN risk assessment and identified R. intestinalis as a potential pain-alleviating probiotic.

The Impact of Daily Walnut Consumption on Gastrointestinal Symptoms: A Mixed-Method Study in Healthy Adults

BACKGROUND

Common gastrointestinal (GI) symptoms such as abdominal pain, indigestion, and constipation affect a significant portion of the global population and can substantially impair quality of life. Despite these widespread issues, research specifically investigating the effects of walnuts on gut function and GI symptoms remain limited.

OBJECTIVE

This study investigates the effects of walnuts on gastrointestinal symptoms in healthy adults.

DESIGN

An experimental baseline-end study with an equivalent group design was employed.

SETTING

The experimental group consumed 42 grams of walnuts daily, and their gastrointestinal symptoms were compared with those of a control group that did not consume walnuts over a 3-week period.

PARTICIPANTS

Sixty university students were recruited as volunteer subjects, consisting of 30 males and 30 females.

INTERVENTION(S)

Participants were randomly assigned to either an experimental group or a control group.

MAIN OUTCOME MEASURE(S)

The independent variable was walnut consumption, and the dependent variable was gastrointestinal health, assessed using the Gastrointestinal Symptom Rating Scale (GSRS) and a qualitative questionnaire to collect participants' perceived changes in GI symptoms.

ANALYSIS

A t-test with a p-value of less than 0.05 and verbatim analysis were utilized.

RESULTS

This mixed-methods study provides evidence for the beneficial effects of walnuts in promoting normal digestive function.

CONCLUSIONS AND IMPLICATIONS

The study provides alternative evidence for the beneficial effects of walnuts in promoting normal digestive function.

Diabetes and gut microbiome

Diabetes mellitus represents a significant global health problem. The number of people suffering from this metabolic disease is constantly rising and although the incidence is heterogeneous depending on region, country, economic situation, lifestyle, diet and level of medical care, it is increasing worldwide, especially among youths and children, mainly due to lifestyle and environmental changes. The pathogenesis of the two most common subtypes of diabetes mellitus, type 1 (T1DM) and type 2 (T2DM), is substantially different, so each form is characterized by a different causation, etiology, pathophysiology, presentation, and treatment. Research in recent decades increasingly indicates the potential role of the gut microbiome in the initiation, development, and progression of this disease. Intestinal microbes and their fermentation products have an important impact on host metabolism, immune system, nutrient digestion and absorption, gut barrier integrity and protection against pathogens. This review summarizes the current evidence on the changes in gut microbial populations in both types of diabetes mellitus. Attention is focused on changes in the abundance of specific bacterial groups at different taxonomic levels in humans, and microbiome shift is also assessed in relation to geographic location, age, diet and antidiabetic drug. The causal relationship between gut bacteria and diabetes is still unclear, and future studies applying new methodological approaches to a broader range of microorganisms inhabiting the digestive tract are urgently needed. This would not only provide a better understanding of the role of the gut microbiome in this metabolic disease, but also the use of beneficial bacterial species in the form of probiotics for the treatment of diabetes.

Gut Microbiota at the Crossroad of Hepatic Oxidative Stress and MASLD

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a prevalent chronic liver condition marked by excessive lipid accumulation in hepatic tissue. This disorder can lead to a range of pathological outcomes, including metabolic dysfunction-associated steatohepatitis (MASH) and cirrhosis. Despite extensive research, the molecular mechanisms driving MASLD initiation and progression remain incompletely understood. Oxidative stress and lipid peroxidation are pivotal in the "multiple parallel hit model", contributing to hepatic cell death and tissue damage. Gut microbiota plays a substantial role in modulating hepatic oxidative stress through multiple pathways: impairing the intestinal barrier, which results in bacterial translocation and chronic hepatic inflammation; modifying bile acid structure, which impacts signaling cascades involved in lipidic metabolism; influencing hepatocytes' ferroptosis, a form of programmed cell death; regulating trimethylamine N-oxide (TMAO) metabolism; and activating platelet function, both recently identified as pathogenetic factors in MASH progression. Moreover, various exogenous factors impact gut microbiota and its involvement in MASLD-related oxidative stress, such as air pollution, physical activity, cigarette smoke, alcohol, and dietary patterns. This manuscript aims to provide a state-of-the-art overview focused on the intricate interplay between gut microbiota, lipid peroxidation, and MASLD pathogenesis, offering insights into potential strategies to prevent disease progression and its associated complications.

Succinate-producing microbiota drives tuft cell hyperplasia to protect against Clostridioides difficile

The role of microbes and their metabolites in modulating tuft cell (TC) dynamics in the large intestine and the relevance of this pathway to infections is unknown. Here, we uncover that microbiome-driven colonic TC hyperplasia protects against Clostridioides difficile infection. Using selective antibiotics, we demonstrate increased type 2 cytokines and TC hyperplasia in the colon but not in the ileum. We demonstrate the causal role of the microbiome in modulating this phenotype using fecal matter transplantation and administration of consortia of succinate-producing bacteria. Administration of succinate production-deficient microbes shows a reduced response in a Pou2f3-dependent manner despite similar intestinal colonization. Finally, antibiotic-treated mice prophylactically administered with succinate-producing bacteria show increased protection against C. difficile-induced morbidity and mortality. This effect is nullified in Pou2f3-/- mice, confirming that the protection occurs via the TC pathway. We propose that activation of TCs by the microbiota in the colon is a mechanism evolved by the host to counterbalance microbiome-derived cues that facilitate invasion by pathogens.

Relationship between dietary fiber physicochemical properties and feedstuff fermentation characteristics and their effects on nutrient utilization, energy metabolism, and gut microbiota in growing pigs

BACKGROUND

There is a growing focus on using various plant-derived agricultural by-products to increase the benefits of pig farming, but these feedstuffs are fibrous in nature. This study investigated the relationship between dietary fiber physicochemical properties and feedstuff fermentation characteristics and their effects on nutrient utilization, energy metabolism, and gut microbiota in growing pigs.

METHODS

Thirty-six growing barrows (47.2 ± 1.5 kg) were randomly allotted to 6 dietary treatments with 2 apparent viscosity levels and 3 β-glucan-to-arabinoxylan ratios. In the experiment, nutrient utilization, energy metabolism, fecal microbial community, and production and absorption of short-chain fatty acid (SCFA) of pigs were investigated. In vitro digestion and fermentation models were used to compare the fermentation characteristics of feedstuffs and ileal digesta in the pig's hindgut.

RESULTS

The production dynamics of SCFA and dry matter corrected gas production of different feedstuffs during in vitro fermentation were different and closely related to the physical properties and chemical structure of the fiber. In animal experiments, increasing the dietary apparent viscosity and the β-glucan-to-arabinoxylan ratios both increased the apparent ileal digestibility (AID), apparent total tract digestibility (ATTD), and hindgut digestibility of fiber components while decreasing the AID and ATTD of dry matter and organic matter (P < 0.05). In addition, increasing dietary apparent viscosity and β-glucan-to-arabinoxylan ratios both increased gas exchange, heat production, and protein oxidation, and decreased energy deposition (P < 0.05). The dietary apparent viscosity and β-glucan-to-arabinoxylan ratios had linear interaction effects on the digestible energy, metabolizable energy, retained energy (RE), and net energy (NE) of the diets (P < 0.05). At the same time, the increase of dietary apparent viscosity and β-glucan-to-arabinoxylan ratios both increased SCFA production and absorption (P < 0.05). Increasing the dietary apparent viscosity and β-glucan-to-arabinoxylan ratios increased the diversity and abundance of bacteria (P < 0.05) and the relative abundance of beneficial bacteria. Furthermore, increasing the dietary β-glucan-to-arabinoxylan ratios led to a linear increase in SCFA production during the in vitro fermentation of ileal digesta (P < 0.001). Finally, the prediction equations for RE and NE were established.

CONCLUSION

Dietary fiber physicochemical properties alter dietary fermentation patterns and regulate nutrient utilization, energy metabolism, and pig gut microbiota composition and metabolites.

Free-caged rearing modes regulate chicken intestinal metabolism by influencing gut microbial homeostasis

Free-caged rearing modes, which prioritize animal welfare, are believed to enhance the quality of animal products. The impact of rearing modes on meat quality may play a key role in the superior quality of local chicken breeds. This study analyzed the cecal contents of free-range and caged black-bone chickens at different ages using metagenomic and metabolomic sequencing. We identified 32 metabolites and 367 microbial species significantly affected by the rearing mode. Linear discriminant analysis Effect Size (LefSe) highlighted five key microorganisms, Gemmiger formicilis, Bacteria unclassified, Bacteroides sp. ET225, Massilistercora timonensis, and Bacteroidales unclassified, that showed distinct abundance patterns across all age points. Among them, Bacteroides sp. ET225 and Massilistercora timonensis were positively associated with certain phospholipids and plant-derived metabolites, while negatively correlated with others like demissidine and acylcarnitine. Functional analysis revealed that rearing modes impact gut metabolites involved in gut metabolism as well as broader processes such as signal transduction, protein digestion, and autophagy. This study offers new insights into how rearing modes influence gut microbiota and metabolites, shedding light on the study of rearing mode-mediated muscle development and fat deposition.

Classifying compounds as prebiotics - scientific perspectives and recommendations

Microbiomes provide key contributions to health and potentially important therapeutic targets. Conceived nearly 30 years ago, the prebiotic concept posits that targeted modulation of host microbial communities through the provision of selectively utilized growth substrates provides an effective approach to improving health. Although the basic tenets of this concept remain the same, it is timely to address certain challenges pertaining to prebiotics, including establishing that prebiotic-induced microbiota modulation causes the health outcome, determining which members within a complex microbial community directly utilize specific substrates in vivo and when those microbial effects sufficiently satisfy selectivity requirements, and clarification of the scientific principles on which the term 'prebiotic' is predicated to inspire proper use. In this Expert Recommendation, we provide a framework for the classification of compounds as prebiotics. We discuss ecological principles by which substrates modulate microbiomes and methodologies useful for characterizing such changes. We then propose statistical approaches that can be used to establish causal links between selective effects on the microbiome and health effects on the host, which can help address existing challenges. We use this information to provide the minimum criteria needed to classify compounds as prebiotics. Furthermore, communications to consumers and regulatory approaches to prebiotics worldwide are discussed.

Sishen Pill & Tongxieyaofang ameliorated ulcerative colitis through the activation of HIF-1α acetylation by gut microbiota-derived propionate and butyrate

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory bowel disease closely related to gut microbiota dysbiosis and intestinal homeostasis imbalance. Sishen Pill&Tongxieyaofang (SSP-TXYF) has a long history of application in traditional Chinese medicine and is widely used in UC clinics. However, its mechanism of action is still unclear.

PURPOSE

This study aimed to explore the potential regulatory role of SSP-TXYF in protecting against UC through metabolites produced by the intestinal microbiota, and elucidate its underlying molecular mechanism.

STUDY DESIGN AND METHODS

16S rRNA and UPLC-QE-Orbitrap-MS were used to assess the microbiota and short-chain fatty acids (SCFAs). A rat model of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced gut microbiota dysbiosis was used to study the effects of SSP-TXYF on UC in vivo. Intestinal epithelial cells-6 (IEC-6) were treated with lipopolysaccharide (LPS). The intestinal mucosal barrier (IMB) functions were investigated by alcian blue staining and western blot analysis. The mechanism of SSP-TXYF influenced the HIF-1α acetylation pathway was examined by real-time fluorescence quantitative PCR (qPCR), Western blotting, and Co-immunoprecipitation.

RESULTS

Using 16S rRNA gene-based microbiota analysis, we found that SSP-TXYF ameliorated TNBS-induced gut microbiota dysbiosis. We found that SSP-TXYF significantly inhibited the decreased abundance of Firmicutes in UC rats, in addition, the abundance of Actinobacteria was also improved. The mechanism of SSP-TXYF-treated TNBS-induced UC resulted from improved IMB functions via the activation of hypoxia-inducible factor-1 (HIF-1α) acetylation. Notably, SSP-TXYF Enriched microbiota-derived metabolites propionate and butyrate, which could activate HIF-1α acetylation in IEC. Furthermore, exogenous treatment of propionate and butyrate reproduced similar protective effects as SSP-TXYF to UC through improving HIF-1α-dependent IMB functions.

CONCLUSIONS

Overall, our findings suggest that the gut microbiota-propionate/butyrate-HIF-1α-IMB axis plays an important role in SSP-TXYF-maintaining intestinal homeostasis, which may represent a novel approach for UC prevention via the intervention of any link in this axis.