Potential beneficial effects of butyrate in intestinal and extraintestinal diseases

Intestinal microbiota and respiratory system diseases: Relationships with three common respiratory virus infections

In recent years, the role of the intestinal microbiota in regulating host health and immune balance has attracted widespread attention. This study provides an in-depth analysis of the close relationship between the intestinal microbiota and respiratory system diseases, with a focus on three common respiratory virus infections, including respiratory syncytial virus (RSV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and influenza virus. The research indicates that during RSV infection, there is a significant decrease in intestinal microbial diversity, suggesting the impact of the virus on the intestinal ecosystem. In SARS-CoV-2 infection, there are evident alterations in the intestinal microbiota, which are positively correlated with the severity of the disease. Similarly, influenza virus infection is associated with dysbiosis of the intestinal microbiota, and studies have shown that the application of specific probiotics exhibits beneficial effects against influenza virus infection. Further research indicates that the intestinal microbiota exerts a wide and profound impact on the occurrence and development of respiratory system diseases through various mechanisms, including modulation of the immune system and production of short-chain fatty acids (SCFAs). This article comprehensively analyzes these research advances, providing new perspectives and potential strategies for the prevention and treatment of future respiratory system diseases. This study not only deepens our understanding of the relationship between the intestinal microbiota and respiratory system diseases but also offers valuable insights for further exploring the role of host-microbiota interactions in the development of diseases.

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.

Cyclosporine combined with dexamethasone regulates hepatic Abca1 and PPARα expression and lipid metabolism via butyrate derived from the gut microbiota

Immunosuppression often leads to drastic metabolic, hormonal, and physiological disorders. Changes in the gut microbiota are believed to be one of the factors contributing to these disorders, but the association remains uncertain. Clinical studies can be complicated by confounding variables, such as diet and other drivers of heterogeneity in human microbiomes. In this study, we identified pronounced gut microbiome signatures in rhesus macaques (RMs) with immunosuppression-induced lipid metabolism disorders following cyclosporine combined with dexamethasone. Furthermore, we observed similar changes in the gut microbiota of mice with immunosuppression-induced lipid metabolism disorders, which were associated with short-chain fatty acid metabolism. ELISA showed that immunosuppression significantly reduced the levels of butyric acid in both feces and serum of mice. Spearman correlation analysis identified a significant correlation between serum butyric acid levels and gut microbial dysbiosis induced by immunosuppression, particularly in relation to f_Lachnospiraceae, g_unidentified_Ruminococcaceae, and s_Clostridium leptum. Additionally, mice transplanted with gut microbiota from immunosuppressed mice exhibited hepatic lipid metabolism disorders, and RNA sequencing revealed significant downregulation of ABC transporters and PPARα in the liver, which was closely associated with lipid transport and metabolism, particularly Abca1. Moreover, butyric acid supplementation alleviated hepatic lipid metabolism disorders and upregulated the expression of Abca1 and PPARα in mice transplanted with immunosuppression-induced gut microbiota. Thus, we propose that the combination of cyclosporine and dexamethasone regulates the expression of hepatic Abca1 and PPARα by modulating the gut microbiota and its derived butyrate, particularly Lachnospiraceae and Clostridium leptum, further regulating hepatic lipid metabolism.

Biosynthesis of a healthy natural sugar D-tagatose: advances and opportunities

D-tagatose is a natural low-calorie rare sugar with nearly the same sweet taste as sucrose. It has nutritional and functional properties of great interest for health, such as anti-diabetes, anti-caries, anti-atherosclerosis, anti-hyperlipidemia, anti-aging, improvement of intestinal microflora, etc. The production of D-tagatose from D-galactose catalyzed by an alkali suffers from limited supplies of costly feedstock (i.e., lactose) and high manufacturing costs due to harsh reaction conditions, costly separation, as well as severe degradation and pollution. In this review, we briefly present the properties of D-tagatose and its physiological effects, review the recent advances in the biosynthesis of D-tagatose from inexpensive and abundant glucans (e.g., starch) and their derivatives (e.g., D-glucose and D-fructose) and from lactose, including both academic literature and industrial patents, as well as discuss its future challenges and opportunities. The biosynthesis of D-tagatose can be catalyzed by four types of biocatalysts: enzymes, whole-cells, microbial fermentation, and in vitro multi-enzyme molecular machines. The biomanufacturing of starchy D-tagatose catalyzed by multi-enzyme molecular machines could be the most promising approach because it not only makes D-tagatose from ample starch but also surpasses the equilibria of monosaccharide isomerization reactions (e.g., D-fructose-to-D-tagatose, D-galactose-to-D-tagatose). D-tagatose as a filler for a variety of food and drinks or a key component mixed with other sweeteners would become a predominant starch-derived sweetener and partially replace high-fructose corn sirup in the future.

Sodium butyrate inhibits the expression of virulence factors in Vibrio cholerae by targeting ToxT protein

Cholera, a diarrheal disease caused by the gram-negative bacterium Vibrio cholerae, remains a global health threat in developing countries due to its high transmissibility and increased antibiotic resistance. There is a pressing need for alternative strategies, with an emphasis on anti-virulent approaches to alter the outcome of bacterial infections, given the increase in antimicrobial-resistant strains. V. cholerae causes cholera by secreting virulence factors in the intestinal epithelial cells. These virulence factors facilitate bacterial colonization and cholera toxin production during infection. Here, we demonstrate that sodium butyrate (SB), a small molecule, had no effect on bacterial viability but was effective in suppressing the virulence attributes of V. cholerae. The production of cholera toxin (CT) was significantly reduced in a standard V. cholerae El Tor strain and two clinical isolates when grown in the presence of SB. Analysis of mRNA and protein levels further revealed that SB reduced the expression of the ToxT-dependent virulence genes like tcpA and ctxAB. DNA-protein interaction assays, conducted at cellular (ChIP) and in vitro conditions (EMSA), indicated that SB weakens the binding between ToxT and its downstream promoter DNA, likely by blocking DNA binding. Furthermore, the anti-virulence efficacy of SB was confirmed in animal models. These findings suggest that SB could be developed as an anti-virulence agent against V. cholerae, serving as a potential alternative to conventional antibiotics or as an adjunctive therapy to combat cholera.

IMPORTANCE

The world has been facing an upsurge in cholera cases since 2021, a similar trend continuing into 2022, with over 29 countries reporting cholera outbreaks (World Health Organization, 16 December 2022, Disease Outbreak News, Cholera-global situation). Treatment of cholera involves oral rehydration therapy coupled with antibiotics to reduce the duration of the illness. However, in recent years, indiscriminate use of antibiotics has contributed to the emergence of antibiotic-resistant strains. In this study, we have addressed the problem of antibiotic resistance by targeting virulence factors. Screening various compounds using in silico methods led to the identification of a small molecule, SB, that inhibits the virulence cascade in V. cholerae. We demonstrated that (i) SB intervened in ToxT protein-DNA binding and subsequently affected the expression of ToxT-regulated virulence genes (ctxAB and tcpA) and (ii) SB is a potential therapeutic candidate for the development of a novel antimicrobial agent.

Akkermansia muciniphila protects against dopamine neurotoxicity by modulating butyrate to inhibit microglia-mediated neuroinflammation

Parkinson's disease (PD) is an age-related and second most common neurodegenerative disease. To date, safe and efficient therapeutic drugs are deficient. In recent years, the relationship between gut microbiota and CNS have received more attention. Homeostatic imbalance of gut microbiota was revealed to participate in the progression of PD. This study detected that Akkermansia muciniphila (A. muciniphila) was apparently decreased in the feces of PD rats via 16S rRNA amplicon sequencing. Furtherly, we found that exogenous supplementation of A. muciniphila could improve 6-OHDA-induced motor dysfunction and dopamine (DA) neuronal damage and neuroinflammatory factors release in PD rats. Moreover, the short-chain fatty acids (SCFAs) sequencing demonstrated that A. muciniphila addition increased butyrate content both in gut and brain. The subsequent functional experiments confirmed that the exogenous supplementation of butyrate conferred neuroprotection against DA neurotoxicity. Mechanically, butyrate targeted microglia to attenuate DA neuronal injury via inhibiting microglia activation and neuroinflammatory factors production. In conclusion, A. muciniphila protected DA neuronal damage by modulating butyrate to inhibit microglia-elicited neuroinflammation. These findings provided a potential application of A. muciniphila on PD treatment.

Efficacy of sodium butyrate in improving nonalcoholic fatty liver disease: A meta-analysis of preclinical studies

BACKGROUND

To evaluate the efficacy of sodium butyrate (NaB) in ameliorating nonalcoholic fatty liver disease (NAFLD) in animals.

METHODS

Chinese and English databases (including PubMed, Embase, Web of Science, Cochrane Library, CNKI, Wangfang Data, CQVIP, and SinoMed) were searched for literature related to NaB to improve the animal model of NAFLD from the establishment of each database to 2023-02. 2 researchers independently screened the literature and extracted the data. The SYRCLE tool was used to assess risk of bias. The extracted data were analyzed using Revman 5.3 and Stata 17.0.

RESULTS

A total of 1008 relevant references were reviewed, and 12 animal experiments involving 192 animals were included in the analysis: 96 in the NaB group and 96 in the model group. The results showed that animals in the NaB group had significantly lower levels of alanine aminotransferase (standardized mean difference (SMD) = -1.29, 95% confidence interval (CI) (-2.08, -0.49), P = .002], aspartate aminotransferase [SMD = -1.13, 95% CI (-1.75, -0.50), P = .0004], NAFLD activity scores [SMD = -3.19, 95%CI(-4.80, -1.58), P = .0001], triglyceride [SMD = -1.28, 95%CI(-1.66, -0.90), P < .00001] and total cholesterol levels [SMD = -1.39, 95%CI(-2.11, -0.67), P = .0002], interleukin-1β [SMD = -1.40, 95%CI (-1.87, -0.92), P < .00001], interleukin-6 [SMD = -1.38, 95%CI (-1.87, -0.90), P < .00001], tumor necrosis factor-alpha [SMD = -1.69, 95% CI (-2.10, -1.28), P < .00001], and other pro-inflammatory factors, and significantly higher tight junction protein-1 expression [SMD = 1.06, 95% CI (0.43,1.69), P = .0009].

CONCLUSION

NaB treatment improves liver function in animals with NAFLD, protected the liver tissue, reduced triglyceride and total cholesterol levels, inhibited inflammation, and protected intestinal barrier function.

Nootropic foods in neurodegenerative diseases: mechanisms, challenges, and future

Neurodegenerative diseases (NDDs) such as Alzheimer's and Parkinson's disease are increasing globally and represent a significant cause of age-related death in the population. Recent studies emphasize the strong association between environmental stressors, particularly dietary factors, and brain health and neurodegeneration unsatisfactory outcomes. Despite ongoing efforts, the efficiency of current treatments for NDDs remains wanting. Considering this, nootropic foods with neuroprotective effects are of high interest as part of a possible long-term therapeutic strategy to improve brain health and alleviate NDDs. However, since it is a new and emerging area in food and neuroscience, there is limited information on mechanisms and challenges to consider for this to be a successful intervention. Here, we seek to address these gaps by presenting a comprehensive review of possible pathways or mechanisms including mutual interactions governing nootropic food metabolism, linkages of the pathways with NDDs, intake, and neuroprotective properties of nootropic foods. We also discuss in-depth intervention with nootropic compounds and dietary patterns in NDDs, providing a detailed exploration of their mechanisms of action. Additionally, we analyze the demand, challenges, and future directions for successful development of nootropic foods targeting NDDs.

Efficacy of probiotic, prebiotic, synbiotic and postbiotic supplementation on gastrointestinal health in cats: systematic review and meta-analysis

OBJECTIVES

The clinical efficacy of the use of probiotics, prebiotics, synbiotics and postbiotics (biotics) in cats is unknown, despite their use in daily practice. The objectives of the study is to evaluate the effectiveness of biotic supplementation in treating and preventing gastroenteropathies, and in reducing gastrointestinal signs associated with antibiotics in cats.

MATERIALS AND METHODS

A systematic review was conducted by searching four databases for publications before August 2, 2024, following a pre-registered protocol. Eligible publications were trials involving healthy cats or those with gastroenteropathies, supplemented with biotics (and an inactive control), studying outcomes such as faecal consistency, faecal microbiota or vomiting. Risk of bias and quality of reports were assessed. Effects were synthesised by meta-analyses and vote counting based on direction of effect. Certainty of evidence was rated using GRADE approach.

RESULTS

Twenty reports were included, presenting unclear or low risk of bias. The evidence did not permit a high-confidence evaluation of the effectiveness of biotics, although five of the seven probiotic trials showed beneficial effects on faecal consistency. Synbiotics presented no clinically relevant effect in reducing antibiotics-associated vomiting, with very low certainty, in a meta-analysis including 32 adult cats. Probiotics significantly reduce the Bacillota/Actinomycetota ratio, with low certainty, in a meta-analysis involving 34 healthy young-adult cats. Following vote counting, probiotics improved immune profile in young cats, and increased butyric acid concentration in healthy cats.

CLINICAL SIGNIFICANCE

Current data highlight the need for further research, especially focused on at-risk groups and sick cats, before advocating the use of biotic supplementation.

Effects of Butyric Acid Supplementation on the Gut Microbiome and Growth Performance of Weanling Pigs Fed a Low-Crude Protein, Propionic Acid-Preserved Grain Diet

Reducing crude protein (CP) in weaner pig diets lowers post-weaning diarrhoea risk but may impair growth performance. This study aimed to identify the beneficial effects of organic acid (OA)-preserved grain and butyric acid supplementation on gut health and growth in low-CP diets. At harvest, grain was divided into two batches: one dried at 65 °C, the other treated with a propionic acid. Ninety-six piglets (28 days old) were assigned to four treatments: (1) dried grain, (2) OA-preserved grain, (3) dried grain + 3% butyric acid, and (4) OA-preserved grain + 3% butyric acid. On day 8, microbial composition, inflammatory markers, volatile fatty acids, and intestinal morphology were assessed. The OA-preserved grain improved feed conversion ratio (p < 0.05) increased beneficial gut bacteria (p < 0.01), elevated caecal butyrate (p < 0.05), reduced jejunal CXCL8 expression (p < 0.05), and enhanced nutrient digestibility (p < 0.01). Butyric acid reduced feed intake (p < 0.05), improved nutrient digestibility (p < 0.01), decreased colonic Proteobacteria (p < 0.05), and increased colonic propionate and butyrate (p < 0.01). Combining OA-preserved grain with butyric acid elevated ileal Proteobacteria and Pasteurellaceae (p < 0.05). In conclusion, while OA-preserved grain improves feed efficiency, nutrient digestibility, and gut microbiota, supplementing butyric acid enhances nutrient digestibility but reduces feed intake, and their combination may disrupt the microbial balance.

Gut Metagenome Reveals the Microbiome Signatures in Tibetan and Black Pigs

The harsh conditions of the Qinghai-Tibet Plateau pose significant physiological challenges to local fauna, often resulting in gastrointestinal disorders. However, Tibetan pigs have exhibited remarkable adaptability to the high-altitude stress of the Tibetan Plateau, a phenomenon that remains not fully understood in terms of their gastrointestinal microbiota. This study collected 57 gastrointestinal tract samples from Tibetan pigs (n = 6) and plain black pigs (n = 6) with comparable genetic backgrounds. Samples from the stomach, jejunum, cecum, colon, and rectum, underwent comprehensive metagenomic analysis to elucidate the gut microbiota-related adaptive mechanisms in Tibetan pigs to the extreme high-altitude environment. A predominance of Pseudomonadota was observed within gut microbiome of Tibetan pigs. Significant differences in the microbial composition were also identified across the tested gastrointestinal segments, with 18 genera and 141 species exhibiting differential abundance. Genera such as Bifidobacterium, Megasphaera, Fusobacterium, and Mitsuokella were significantly more abundant in Tibetan pigs than in their lowland counterparts, suggesting specialized adaptations. Network analysis found greater complexity and modularity in the microbiota of Tibetan pigs compared to black pigs, indicating enhanced ecological stability and adaptability. Functional analysis revealed that the Tibetan pig microbiota was particularly enriched with bacterial species involved in metabolic pathways for propionate and butyrate, key short-chain fatty acids that support energy provision under low-oxygen conditions. The enzymatic profiles of Tibetan pigs, characterized by elevated levels of 4-hydroxybutyrate dehydrogenase and glutaconyl-CoA decarboxylase, highlighted a robust fatty acid metabolism and enhanced tricarboxylic acid cycle activity. In contrast, the gut microbiome of plain black pigs showed a reliance on the succinate pathway, with a reduced butyrate metabolism and lower metabolic flexibility. Taken together, these results demonstrate the crucial role of the gastrointestinal microbiota in the adaptation of Tibetan pigs to high-altitude environments by optimizing carbohydrate metabolism and short-chain fatty acid production for efficient energy utilization. This study not only highlights the metabolic benefits conferred by the gut microbiota of Tibetan pigs in extreme environments, but also advances our understanding of the adaptive gastrointestinal mechanisms in plateau-dwelling animals. These insights lay the foundation for exploring metabolic interventions to support health and performance in high-altitude conditions.

Gut microbiota in colorectal cancer: a review of its influence on tumor immune surveillance and therapeutic response

Colorectal cancer (CRC) poses a significant global health burden, with gut microbiota emerging as a crucial modulator of CRC pathogenesis and therapeutic outcomes. This review synthesizes current evidence on the influence of gut microbiota on tumor immune surveillance and responses to immunotherapies and chemotherapy in CRC. We highlight the role of specific microbial taxa in promoting or inhibiting tumor growth and the potential of microbiota-based biomarkers for predicting treatment efficacy. The review also discusses the implications of microbiota modulation strategies, including diet, probiotics, and fecal microbiota transplantation, for personalized CRC management. By critically evaluating the literature, we aim to provide a comprehensive understanding of the gut microbiota's dual role in CRC and to inform future research directions in this field.

The Critical Role of Faecalibacterium prausnitzii in Cardiovascular Diseases

Due to the continued aging of the global population, cardiovascular diseases (CVDs) remain the main cause of death worldwide, with millions of fatalities from diseases, including stroke and coronary artery disease, reported annually. Thus, novel therapeutic approaches and targets are urgently required for diagnosing and treating CVDs. Recent studies emphasize the vital part of gut microbiota in both CVD prevention and management. Among these, Faecalibacterium prausnitzii (F. prausnitzii) has emerged as a promising probiotic capable of improving intestinal health. Although preliminary investigations demonstrate that F. prausnitzii positively enhances cardiovascular health, research specifically connecting this strain to CVD outcomes remains limited. Based on current research and assessment of possible clinical applications, this paper aimed to investigate the positive effects on cardiovascular health using F. prausnitzii and its metabolites. Targeting gut flora is expected to become a mainstay in CVD treatment as research develops.

IUPHAR review: Eating disorders, gut microbiota dysbiosis and epigenetic aberrations

Eating disorders (EDs) are a heterogeneous class of increasing mental disorders that are characterized by disturbances in eating behaviors, body weight regulation, and associated psychological dysfunctions. These disorders create physiological imbalances that alter the diversity and composition of the gut microbiota. While evidence suggests that EDs can arise from epigenetic aberrations, alterations in gut microbial communities may also contribute to the development and/or persistence of EDs through epigenetic mechanisms. Understanding the interplay among gut microbial communities, epigenetic processes, and the risk of EDs provides opportunities for designing preventive and/or therapeutic interventions through gut microbiome modulation. This review highlights how microbiome-based therapeutics and specific dietary interventions can contribute to improving various subtypes of EDs by modulating gut microbial communities and mitigating epigenetic aberrations. First, we briefly review the literature on links between epigenetic aberrations and the pathophysiology of EDs. Second, we examine the potential role of the gut microbiome in the pathogenesis of EDs through epigenetic mechanisms. Next, we explore the associations between EDs and other psychiatric disorders, and examine the potential roles of the microbiome in their pathogenesis. Finally, we present evidence supporting the potential of microbiome-based therapeutics and specific dietary interventions to improve EDs through epigenetic modifications.

Crosstalk between gut microbiotas and fatty acid metabolism in colorectal cancer

Colorectal cancer (CRC) is the third most common malignancy globally and the second leading cause of cancer-related mortality. Its development is a multifactorial and multistage process influenced by a dynamic interplay between gut microbiota, environmental factors, and fatty acid metabolism. Dysbiosis of intestinal microbiota and abnormalities in microbiota-associated metabolites have been implicated in colorectal carcinogenesis, highlighting the pivotal role of microbial and metabolic interactions. Fatty acid metabolism serves as a critical nexus linking dietary patterns with gut microbial activity, significantly impacting intestinal health. In CRC patients, reduced levels of short-chain fatty acids (SCFAs) and SCFA-producing bacteria have been consistently observed. Supplementation with SCFA-producing probiotics has demonstrated tumor-suppressive effects, while therapeutic strategies aimed at modulating SCFA levels have shown potential in enhancing the efficacy of radiation therapy and immunotherapy in both preclinical and clinical settings. This review explores the intricate relationship between gut microbiota, fatty acid metabolism, and CRC, offering insights into the underlying mechanisms and their potential translational applications. Understanding this interplay could pave the way for novel diagnostic, therapeutic, and preventive strategies in the management of CRC.

The Relationship Between Fiber Intake and Gut Bacterial Diversity and Composition During the Third Trimester of Pregnancy

BACKGROUND/OBJECTIVES

High fiber (34-36 g/day) diets are recommended during pregnancy due to inverse associations with constipation and adverse pregnancy health outcomes, including pre-eclampsia and gestational diabetes. However, the mechanism for this protective effect is poorly defined. Fiber may be protective due to its impact on the composition and function of specific bacteria within the pregnancy gut microbiome. The purpose of this analysis was to investigate whether a sub-sample of cohort study participants in their third trimester met daily dietary fiber and vegetable intake recommendations and, in turn, how this impacted bacterial composition and butyrate-producing genes within the gut microbiome.

METHODS

Pregnant participants (n = 52) provided stool samples and survey data, which were used to calculate fiber and vegetable intake. Genomic DNA was extracted from the stool samples, followed by PCR to amplify the V4 region of the 16S rRNA gene. Amplicons were sequenced and mapped to the RDP reference. Quantitative real-time PCR was used to measure the abundance of bacterial genes for butyrate production.

RESULTS

Of the pregnant participants in this sample, 84.7% and 92.3% failed to meet recommendations in the Dietary Guidelines for Americans for dietary fiber and vegetable intake, respectively. All four participants who met the vegetable recommendation were a subset of those who met the fiber recommendation. The participants who met the pregnancy fiber recommendation had gut microbiotas with greater alpha diversity (Shannon and Inverse Simpson) than those who did not. However, there was no association between dietary fiber intake and the abundance of bacterial genes for butyrate production.

CONCLUSIONS

This research suggests that general fiber intake during pregnancy has a modest association with the gut bacterial community. These preliminary results demonstrate a need to improve fiber intake during pregnancy. Further, studies that measure the relationship between dietary intake of specific types of fiber and associations with specific gut bacterial community members and their functions are needed.

Gut microbiota in Crohn's disease pathogenesis

Inflammatory bowel diseases (IBDs) are classified into two distinct types based on the area and severity of inflammation: Crohn's disease (CD) and ulcerative colitis. In CD, gut bacteria can infiltrate mesenteric fat, causing expansion known as creeping fat, which may limit bacterial spread and inflammation but can promote fibrosis. The gut bacteria composition varies depending on whether the colon or ileum is affected. Fecal microbiota transplantation (FMT) transfers feces from a healthy donor to restore gut microbiota balance, often used in IBD patients to reduce inflammation and promote mucosal repair. The use of FMT for CD remains uncertain, with insufficient evidence to fully endorse it as a definitive treatment. While some studies suggest it may improve symptoms, questions about the duration of these improvements and the need for repeated treatments persist. There is a pressing need for methods that provide long-term benefits, as highlighted by Wu et al's research.

Prospective analysis of biomarkers associated with successful faecal microbiota transplantation in recurrent Clostridioides difficile infection

OBJECTIVES

Faecal microbiota transplantation (FMT) is an established treatment for recurrent Clostridioides difficile infection (CDI). This study aimed to identify calprotectin and microbiome characteristics as potential biomarkers of FMT success.

METHODS

We conducted a prospective study of patients who underwent oral FMT (single dose of 4-5 capsules) for recurrent CDI (January 2018 to December 2022). Samples were collected at three time points: at CDI diagnosis, within 24 hours before FMT administration, and 30 days post-FMT. Calprotectin levels were assessed and the V4 region of the 16S rRNA gene was sequenced to analyse the microbiota composition. Sequencing data analysis and statistical analysis were performed using MOTHUR and R.

RESULTS

Ninety-seven patients underwent FMT (totalling 105 procedures). A total of 221 samples were processed, including 21 donor samples, 24 capsule contents, and 176 patient faecal samples (39 at diagnosis, 63 pre-FMT, and 74 post-FMT). FMT achieved an overall success rate of 85.1% (86/101 cases). The abundance of Bacteroides, Ruminococcus, Megamonas, and certain Prevotella operational taxonomic units was significantly higher in capsules associated with 100% success compared with less effective capsules. FMT engraftment was observed in 95% of patients with favourable outcomes versus 62% of those with recurrences (p 0.006). Additionally, a negative correlation was found between calprotectin levels and specific microbial genera, suggesting an association with successful outcomes.

DISCUSSION

This study highlights differences in the evolution of faecal microbiota, bacterial engraftment, and inflammation markers (e.g. calprotectin) between patients with varying FMT outcomes. Potential biomarkers for successful FMT were identified, providing valuable insights for optimizing FMT strategies.

Age-Related Changes in Gut Health and Behavioral Biomarkers in a Beagle Dog Population

The gut and the gut microbiome communicate with the nervous system through the gut-brain axis via neuroimmune and neuroendocrine mechanisms. Despite existing research, studies exploring this link in aging dogs are limited. This study aims to examine multiple blood and fecal biomarkers of intestinal health, along with various behavioral indicators based on saliva, blood, observations, and activity, in different age populations (junior: <2 y.o.; adult: 2-7 y.o.; senior: >7 y.o.) of thirty-seven Beagle dogs. In our study, Bacteroides were significantly higher in senior dogs. The relative abundance of Faecalibacterium and Blautia showed age-related trends, higher in senior and junior dogs, respectively. Fecal short-chain fatty acid concentration, especially acetate, increased with age, while propionate was higher in junior dogs. For the behavioral indicators we considered, blood thyroxine concentration, playing, exploring, and total activity were higher in junior dogs. The differences observed between the biomarkers of gut health and behavior, particularly those significant for the age correlations, emphasize the importance of considering age-related factors when studying the gut microbiome and behavior. However, further research is needed to better understand the mechanisms and specific pathways involved in the relationship between the studied biomarkers and age.

Sodium Butyrate: A Multifaceted Modulator in Colorectal Cancer Therapy

Background and Objectives: Sodium butyrate (NaB) is a potent modulator of cancer-related gene networks. However, its precise mechanisms of action and effects at elevated doses remain insufficiently explored. This study investigated the impact of NaB at physiologically relevant doses on key cellular metrics (viability, confluence, cell number, morphology, nuclear integrity) and a comprehensive set of apoptosis and proliferation regulators (including underexplored genes) in colorectal cancer (CRC) cells. Materials and Methods: Human HCT-116 cells were treated with increasing NaB concentrations (0-20 mM). Cell viability, confluence, number, morphology, and nuclear integrity were assessed using MTT and imaging assays. RT-PCR was used to determine changes in the expression of critical pro-apoptotic players (BAX, CASP3, PUMA, TP53), anti-apoptotic facilitators (BCL-2, MCL-1), cell division regulators (PCNA, Ki-67, CDKN1), and inflammation genes (NF-κB). Results: This study provides the first exploration of MCL-1 and PCNA modulation by NaB in the context of CRC and HCT-116 cells, offering significant translational insights. All treatments reduced cell viability, confluence, and number in a dose-dependent manner (p < 0.0001). Gene expression revealed dose-related increases in most pro-apoptotic markers (BAX, CASP3, PUMA; p < 0.001), and decreases for the other genes (p < 0.001). BAX emerged as the most responsive gene to NaB, while TP53 showed minimal sensitivity, supporting NaB's effectiveness in p53-compromised phenotypes. Nuclear condensation and fragmentation at higher NaB doses confirmed apoptotic induction. Conclusions: NaB can modulate critical apoptotic and cell cycle genes, disrupt tumor cell proliferation, and overcome resistance mechanisms associated with anti-apoptotic regulators such as MCL-1. By targeting both short-term and long-term anti-apoptotic defenses, NaB shows promise as a preventive and therapeutic agent in CRC, particularly in high-risk phenotypes with compromised p53 functionality. These findings support its potential for integration into combination therapies or dietary interventions aimed at enhancing colonic butyrate levels.

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.

Effects of antibiotic therapy on the early development of gut microbiota and butyrate-producers in early infants

Background

Antibiotics, as the most commonly prescribed class of drugs in neonatal intensive care units, have an important impact on the developing neonatal gut microbiota. Therefore, comprehending the effects of commonly used antibiotic therapy on the gut microbiota and butyrate-producers in early infants could provide information for therapeutic decision-making in the NICU.

Objectives

To explore the effects of antibiotic therapy on the early development of gut microbiota and butyrate-producers in early infants.

Methods

A total of 72 infants were included in the study. We performed 16S rRNA sequencing on stool swab samples collected from neonatal intensive care unit patients who received amoxicillin-clavulanic acid (AC, n = 10), moxalactam (ML, n = 28) and non-antibiotics (NA, n = 34). We then compared the taxonomic composition between treatment regimens, focusing on differences in butyrate-producers.

Results

Our study showed that there were significant differences in Shannon index (p = 0.033) and Beta diversity (p = 0.014) among the three groups. At the family level, compared with the other two groups, the relative abundance of Clostridiaceae (p < 0.001) and Veillonellaceae (p = 0.004) were significantly higher, while the relative abundance of Enterococcidae (p < 0.001) was significantly lower in the NA group. The relative abundance of Enterobacteriaceae (p = 0.022) in the AC group was greater than that in the other two groups. Additionally, butyrate-producers (p < 0.001), especially Clostridiaceae (p < 0.001), were noticeably more abundant in the NA group. The relative abundance of Clostridiaceae and butyrate-producers were the lowest in the ML group (p < 0.001).

Conclusion

We found that antibiotic therapy had an adverse impact on the initial development of gut microbiota and leaded to a reduction in the abundance of butyrate-producers, particularly Clostridiaceae. Furthermore, moxalactam had a more pronounced effect on the gut microbiota compared to amoxicillin-clavulanic acid.

Butyrate: A potential mediator of obesity and microbiome via different mechanisms of actions

Butyrate, a short-chain fatty acid, is a crucial product of gut microbial fermentation with significant implications for various metabolic and physiological processes. Dietary sources of butyrate are limited, primarily derived from the fermentation of dietary fibers by butyrate-producing gut bacteria. Butyrate exerts its effects primarily as a histone deacetylase (HDAC) inhibitor and through signaling pathways involving G protein-coupled receptors (GPCRs). Its diverse benefits include promoting gut health, enhancing energy metabolism, and potentially alleviating complications associated with obesity. However, the exact role of butyrate in obesity is still under investigation, with a limited number of human trials necessitating further research to determine its efficacy and safety profile. Moreover, butyrate impact on the gut-brain axis and its modulation of microbiome effect on behavior highlight its broader importance in regulating host physiology. A thorough understanding of the metabolic pathways and mechanisms of butyrate is essential for developing targeted interventions for metabolic disorders. Continued research is crucial to fully realize its therapeutic potential and optimize its clinical applications in human health. In summary, this review illuminates the multifaceted role of butyrate as a potential mediator of obesity and related metabolic changes.

Microbial Metabolites-induced Epigenetic Modifications for Inhibition of Colorectal Cancer: Current Status and Future Perspectives

Globally, one of the most prevalent cancers is colorectal cancer (CRC). Chemotherapy and surgery are two common conventional CRC therapies that are frequently ineffective and have serious adverse effects. Thus, there is a need for complementary and different therapeutic approaches. The use of microbial metabolites to trigger epigenetic alterations as a way of preventing CRC is one newly emerging field of inquiry. Small chemicals called microbial metabolites, which are made by microbes and capable of altering host cell behaviour, are created. Recent research has demonstrated that these metabolites can lead to epigenetic modifications such as histone modifications, DNA methylation, and non-coding RNA regulation, which can control gene expression and affect cellular behaviour. This review highlights the current knowledge on the epigenetic modification for cancer treatment, immunomodulatory and anti-carcinogenic attributes of microbial metabolites, gut epigenetic targeting system, and the role of dietary fibre and gut microbiota in cancer treatment. It also focuses on short-chain fatty acids, especially butyrates (which are generated by microbes), and their cancer treatment perspective, challenges, and limitations, as well as state-of-the-art research on microbial metabolites-induced epigenetic changes for CRC inhibition. In conclusion, the present work highlights the potential of microbial metabolites-induced epigenetic modifications as a novel therapeutic strategy for CRC suppression and guides future research directions in this dynamic field.

Sodium Butyrate, A Gut Microbiota Derived Metabolite in Type 2 Diabetes Mellitus and Cardiovascular Disease: A Review

Type 2 diabetes is characterized by elevated blood glucose levels, leading to an increased risk of cardiovascular diseases. Sodium butyrate, the sodium salt of the short-chain fatty acid butyric acid produced by gut microbiota fermentation, has shown promising effects on metabolic diseases, including type 2 diabetes and cardiovascular diseases. Sodium butyrate demonstrates anti-inflammatory, anti-oxidative, and lipid-lowering properties and can improve insulin sensitivity and reduce hepatic steatosis. In this review, we investigate how sodium butyrate influences cardiovascular complications of type 2 diabetes, including atherosclerosis (AS), heart failure (HF), hypertension, and angiogenesis. Moreover, we explore the pathophysiology of cardiovascular disease in type 2 diabetes, focusing on hyperglycemia, oxidative stress, inflammation, and genetic factors playing crucial roles. The review suggests that sodium butyrate can be a potential preventive and therapeutic agent for cardiovascular complications in individuals with type 2 diabetes.

Compositional characteristics of the gut microbiome in patients with uremia

ABSTRACT

During acute or chronic uremia, the cumulative harmful effects of uremic toxins result in numerous health problems and, ultimately, mortality. Previous research has identified that uremic retention solutes originate from the gut microbiome, indicating that uremia may be closely associated with gut microbiome dysbiosis. To deepen our understanding of the compositional characteristics of the gut microbiome in patients with uremia and thereby promote precision medicine in the treatment of uremia, we conducted a study of the compositional characteristics of the gut microbiome in 20 patients with uremia. The gut microbiome diversity of uremic patients and the control group showed certain differences. Nonmetric multidimensional scaling analysis showed that the beta diversity of the gut microbiome of uremic patients was significantly different from that of the healthy control individuals, with a distinct clustering effect in the uremic patient group, and it also showed a similarly distinct clustering effect in the healthy control group. The Chao1 index and Sobs index were significantly lower in the uremic patient group than in the healthy control group ( P < 0.05). By analyzing the composition and abundance distribution of the gut microbiome in the uremic patient group and healthy control group, we found that the relative abundance of the gut microbiome constituents Fusobacteriota , Enterobacteriaceae, Oscillospirales, Ruminococcaceae, and Lachnospiraceae was significantly increased in the intestines of uremic patients. We also detected the rare taxa Erysipelotrichaceae, which was present only in the uremic patient group. Predictive functional analysis suggested that an increased abundance of Ruminococcaceae and Lachnospirales, which are associated with indoxyl sulfate and phenylacetyl glutamine, and an increased abundance of Oscillospirales, which is associated with pyruvate metabolism, in uremic patients may strongly influence the gut environment according to renal function, resulting in dysbiosis associated with uremic toxin production. Rare taxa such as Erysipelotrichaceae have been suggested to be detrimental to intestinal disease. Further research into these gut microbiomes may provide new ideas for the prevention and treatment of uremia with the gut microbiome.

Functional kombucha production from fusions of black tea and Indian gooseberry (Phyllanthus emblica L.)

The use of alternative ingredients as supplements to or blends with kombucha tea to improve organoleptic properties and health effects has recently increased. Indian gooseberry fruit is among the most promising alternative raw materials for producing functional kombucha since the berries contain several beneficial substances. In this study, the production of functional kombucha beverages from fusions of black tea and Indian gooseberry fruit homogenate (IGH) was investigated, and the chemical and biological properties of kombucha products were evaluated and compared with those of traditional black tea kombucha products. Chemical composition analysis revealed that IGH contains high amounts of polyphenols (627.4 mg GAE/L or 129.51 mg GAE/g dry weight), flavonoids (98.0 mg QE/L or 9.11 mg QE/g dry weight), and vitamins, specifically ascorbic acid (465.72 mg/100 g fresh weight). It also contains several amino acids, fatty acids, and trace elements. Supplementing or blending black tea kombucha with IGH in the range of 10 %-50 % (v/v) increased the total phenolic content (TPC), total flavonoid content (TFC), and total acidity of the fermented beverages. Several volatile organic compounds associated with the flavor, aroma, and health benefits of kombucha were also detected in black tea and IGH fusion kombucha products. Moreover, the black tea and IGH fusion kombucha products also displayed greater antioxidant and antimicrobial activities than the traditional black tea kombucha. Among the different combinations of black tea and IGH, supplementing black tea kombucha with 20 % IGH was the best combination for producing alternative and unique functional kombucha products with notable nutritional and health benefits.

SLC26A3 (DRA, the Congenital Chloride Diarrhea Gene): A Novel Therapeutic Target for Diarrheal Diseases

Diarrhea associated with enteric infections, gut inflammation, and genetic defects poses a major health burden and results in significant morbidity and mortality. Impaired fluid and electrolyte absorption or secretion in the intestine are the hallmark of diarrhea. Electroneutral NaCl absorption in the mammalian GI tract involves the coupling of Na+/H+ and Cl-/HCO3- exchangers. SLC26A3 (Down Regulated in Adenoma, DRA) is the major anion exchanger involved in luminal Cl- absorption and HCO3- secretion. Mutations in the SLC26A3 gene cause a severe disease called congenital chloride diarrhea (CLD). Multiple studies have shown that DRA function or expression is downregulated in infectious diarrheal disorders caused by EPEC, C rodentium, Salmonella, Clostridioides difficile and Cryptosporidium parvum infection. In addition, DRA levels are severely depleted in colonic mucosa of IBD patients and in mouse models of IBD (eg, DSS, TNBS, adoptive T-cell transfer, anti-CD-40, and IL-10 KO colitis). In addition, genetic defects exhibiting diarrhea including microvillus inclusion disease (MVID), keratin-8 depletion, knock-out mouse models of transcriptional factors (eg, CDX-2 and HNF1α/1β) also exhibit severe down regulation of DRA. Also, recent studies have shown that DRA is not only critical for chloride absorption but also plays a key role in maintaining gut epithelial barrier integrity, microbiome composition, and has now emerged as an IBD susceptibility gene. In this review, we provide strong evidence that DRA may serve as a novel therapeutic target with dual benefits in not only correcting diarrheal phenotype but also improving gut barrier integrity and inflammation in pathogen infection or IBD.

The role of the gut microbiota and the nicotinate/nicotinamide pathway in rotenone-induced neurotoxicity

Rotenone is a natural compound from plants. It is widely used in pesticides because of highly toxic to insects and fish. However, lots of research has reported that rotenone has neurotoxic effects in humans. It is confirmed there is a correlation between rotenone exposure and Parkinson's disease (PD). Therefore, the role of gut microbiota and related metabolic pathways was investigated in rotenone-induced neurotoxicity. The results showed that the abundance of gut microbiota changed significantly. The differential metabolites were enriched in the nicotinate and nicotinamide metabolism pathways, which had the greatest impact on the entire metabolic system. The contents of acetic acid and butyric acid in intestinal tissues decreased significantly. Additionally, Interleukin-6 (IL-6), Tumor necrosis factor alpha (TNF-α) and vasoactive intestinal peptide (VIP) were significantly up-regulated, while gastrin (GAS) and Ghrelin were significantly down-regulated. Expression of intestinal tight junction protein was significantly reduced. Moreover, nicotinamide adenine dinucleotide (NAD+), a the product of the nicotinate/nicotinamide pathways, decreased significantly. And the expression levels of nicotinamide phosphoribosyl transferase (NAMPT) and Solute Carrier Family 25 Member 51 (SLC25A51) also reduced significantly. Therefore, gut microbiota was influenced obviously in rats exposed to rotenone, leading to a decrease of acetic acid and butyric acid contents, which might in turn affect the change of intestinal barrier permeability and induce inflammatory reactions. Meanwhile, the nicotinate/nicotinamide metabolic pathways might play an important role in rats exposed to rotenone.

Associations of Stool Metal Exposures with Childhood Gut Microbiome Multiomics Profiles in a Prospective Birth Cohort Study

Metal exposures are closely related to childhood developmental health. However, their effects on the childhood gut microbiome, which also impacts health, are largely unexplored using microbiome multiomics including the metagenome and metatranscriptome. This study examined the associations of fecal profiles of metal/element exposures with gut microbiome species and active functional pathways in 8- to 12-year-old children (N = 116) participating in the GESTation and Environment (GESTE) cohort study. We analyzed 19 stool metal and element concentrations (B, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Ba, and Pb). Covariate-adjusted linear regression models identified several significant microbiome associations with continuous stool metal/element concentrations. For instance, Zn was positively associated with Turicibacter sanguinis (coef = 1.354, q-value = 0.039) and negatively associated with Eubacterium eligens (coef = -0.794, q-value = 0.044). Higher concentrations of Cd were associated with lower Eubacterium eligens (coef = -0.774, q-value = 0.045). Additionally, a total of 490 significant functional pathways such as biosynthesis and degradation/utilization/assimilation were identified, corresponding to different functions, including amino acid synthesis and carbohydrate degradation. Our results suggest links among metal exposures, pediatric gut microbiome multiomics, and potential health implications. Future work will further explore their relation to childhood health.

Effects of non-digestible carbohydrates on gut microbiota and microbial metabolites: a randomised, controlled dietary intervention in healthy individuals

The gut microbiome is impacted by certain types of dietary fibre. However, the type, duration and dose needed to elicit gut microbial changes and whether these changes also influence microbial metabolites remain unclear. This study investigated the effects of supplementing healthy participants with two types of non-digestible carbohydrates (resistant starch (RS) and polydextrose (PD)) on the stool microbiota and microbial metabolite concentrations in plasma, stool and urine, as secondary outcomes in the Dietary Intervention Stem Cells and Colorectal Cancer (DISC) Study. The DISC study was a double-blind, randomised controlled trial that supplemented healthy participants with RS and/or PD or placebo for 50 d in a 2 × 2 factorial design. DNA was extracted from stool samples collected pre- and post-intervention, and V4 16S rRNA gene sequencing was used to profile the gut microbiota. Metabolite concentrations were measured in stool, plasma and urine by high-performance liquid chromatography. A total of fifty-eight participants with paired samples available were included. After 50 d, no effects of RS or PD were detected on composition of the gut microbiota diversity (alpha- and beta-diversity), on genus relative abundance or on metabolite concentrations. However, Drichlet's multinomial mixture clustering-based approach suggests that some participants changed microbial enterotype post-intervention. The gut microbiota and fecal, plasma and urinary microbial metabolites were stable in response to a 50-d fibre intervention in middle-aged adults. Larger and longer studies, including those which explore the effects of specific fibre sub-types, may be required to determine the relationships between fibre intake, the gut microbiome and host health.

Intestinal Microbiota and Aging in People with HIV-What We Know and What We Don't

PURPOSE OF REVIEW

People with HIV (PWH) experience premature aging and an elevated risk of age-related comorbidities, even with viral suppression through antiretroviral therapy (ART). We examine gastrointestinal disruptions, specifically impaired intestinal barrier integrity and microbial dysbiosis, as contributors to these comorbidities.

RECENT FINDINGS

HIV infection compromises the intestinal epithelial barrier, increasing permeability and microbial translocation, which trigger inflammation and cellular stress. ART does not fully restore gut barrier integrity, leading to persistent inflammation and cellular stress. Additionally, HIV-associated microbial dysbiosis favors pro-inflammatory bacteria, intensifying inflammation and tissue damage, which may contribute to premature aging in PWH. Understanding the interactions between intestinal microbiota, chronic inflammation, cellular stress, and aging is essential to developing therapies aimed at reducing inflammation and slowing age-related diseases in PWH. In this review, we discuss critical knowledge gaps and highlight the therapeutic potential of microbiota-targeted interventions to mitigate inflammation and delay age-associated pathologies in PWH.

Inhalation of 2,2',5,5'-tetrachlorobiphenyl (PCB52) causes changes to the gut microbiome throughout the gastrointestinal tract

Polychlorinated biphenyls (PCBs), such as PCB52, are hazardous environmental contaminants present in indoor and outdoor environments. Oral PCB exposure affects the colon microbiome; however, it is unknown if inhalation of PCBs alters the intestinal microbiome. We hypothesize that sub-acute inhalation of PCB52 affects microbial communities depending on the location in the (GI) gastrointestinal tract and the local profiles of PCB52 and its metabolites present in the GI tract following mucociliary clearance and biliary or intestinal excretion. Sprague-Dawley rats were exposed via nose-only inhalation 4 h per day, 7 days per week, for 4 weeks to either filtered air or PCB52. After 28 days, differences in the microbiome and levels of PCB52 and its metabolites were characterized throughout the GI tract. PCB52 inhalation altered taxa abundances and predicted functions altered throughout the gut, with most alterations occurring in the large intestine. PCB52 and metabolite levels varied across the GI tract, resulting in differing PCB × microbiome networks. Thus, the presence of different levels of PCB52 and its metabolites in different parts of the GI tract has varying effects on the composition and predicted function of microbial communities. Future studies need to investigate whether these changes lead to adverse outcomes.

Analysis of composition of gut microbial community in a rat model of functional dyspepsia treated with Simo Tang

OBJECTIVE

To investigate composition of gut microbial community in a rat model of functional dyspepsia (FD) and to explore the interventional effects of Simo Tang (, SMT).

METHODS

A rat model of FD was established through the tail-clamping stimulation method. The rat model of FD was assessed by the state of rats, their weight, sucrose preference rate, and intestinal propulsion rate. The DNA was extracted from stool samples after treatment with SMT. Amplified polymerase chain reaction (PCR) products of the 16S rDNA were sequenced using NovaseQ6000 after construction of libraries. Composition of gut microbial community in the stool samples was determined and analyzed by cluster analysis, bioinformatic analysis, and analysis of α-diversity and β-diversity.

RESULTS

The rat model of FD was successfully established using the tail-clamping stimulation method. The statistical results of cluster analysis of operational taxonomic units (OTUs) showed that the relative abundance of OTUs in the FD group was the lowest, while it was the highest in the normal (N) group. The composition of microbiome in the four groups was similar at phyla level. Compared with the FD group, the abundance of Firmicutes was downregulated, and the abundance of Proteobacteria and Bacteroidetes was upregulated in the Simo Tang (SMT) and high-dose Simo Tang (SMT.G) groups. The ratio of Bacteroidetes/ Firmicutes was also elevated. According to the analysis of α-diversity and β-diversity, the abundance of flora in FD rats was significantly reduced. The treatment using SMT appeared beneficial to improve the diversity of flora. SMT could improve the intestinal flora in FD rats. The results showed that FD rats had intestinal flora imbalance, and species diversity increased. The results suggested that SMT could regulate the disorders of intestinal flora caused by FD.

CONCLUDIONS

SMT could restore gut homeostasis and maintain gut flora diversity by modulating the gut microbiota and its associated metabolites in rats, thereby treating gastrointestinal diseases.

Evaluation of Four Multispecies Probiotic Cocktails in a Human Colonic Fermentation Model

Bacteriotherapy represents an attractive approach for both prophylaxis and treatment of human diseases. However, combining probiotic bacteria in "cocktails" is underexplored, despite its potential as an alternative multi-target therapy. Herein, three-strain probiotic mixtures containing different combinations of Bacillus (Bc.) coagulans [ATB-BCS-042], Levilactobacillus (Lv.) brevis [THT 0303101], Lacticaseibacillus (Lc.) paracasei [THT 031901], Bacillus subtilis subsp. natto [ATB-BSN-049], Enterococcus faecium [ATB-EFM-030], and Bifidobacterium (Bf.) animalis subsp. lactis [THT 010802] were prepared. Four cocktails (PA: Bc. coagulans + Lv. brevis + Lc. paracasei, PB: Bc. subtilis subsp. natto + Lv. brevis + Lc. paracasei, PC: E. faecium + Lv. brevis + Lc. paracasei, PD: Bc. coagulans + Lv. brevis + Bf. animalis subsp. lactis) were tested using a short-term (72 h) simulation of the human colonic microbiota in a final dose of 6 × 109 CFU. All these probiotic mixtures significantly increased butyrate production compared to the parallel control experiment. PA and PB promoted a bifidogenic effect and facilitated lactobacilli colonization. Furthermore, reporter gene assays using the AhR_HT29-Lucia cell line revealed that fermentation supernatants from PA and PB notably induced AhR transactivity. Subsequent examination of the metabolic outputs of PA and PB in intestinal epithelial models using cell culture inserts suggested no significant impact on the transepithelial electrical resistance (TEER). Assessment of the expression of proinflammatory and anti-inflammatory cytokines, as well as AhR-related target genes in the Caco-2 cell monolayers indicated that PB's metabolic output upregulated most of the measured endpoints. This in vitro investigation evaluated the potential impact of four multispecies probiotic mixtures in the human colonic microbiota and identified a promising formulation comprising a combination of Bc. subtilis subsp. natto, Lv. brevis, and Lc. paracasei as a promising formulation for further study.

Butyrate modulates gut microbiota and anti-inflammatory response in attenuating cisplatin-induced kidney injury

In our previous research, we reported that administering probiotics Lactobacillus reuteri and Clostridium butyricum (LCs) before cisplatin treatment effectively modifies structures of the gut microbiota and restore ecological balance and significantly increases butyrate levels, a process closely associated with reducing cisplatin-induced nephrotoxicity. This study aims to investigate further whether the elevation of metabolite butyrate in the gut, promoted by probiotics LCs, can effectively mitigate the nephrotoxic effects of cisplatin and the progression of renal senescence in rats. Results show that butyrate administration significantly improved kidney function and decreased renal fibrosis in a dose-dependent manner compared to the cisplatin group. Its effects were associated with reductions in inflammatory responses, evidenced by decreased levels of key inflammatory markers, including KIM-1, MPO, NOX2, F4/80, and TGF-β1, alongside increased production of the anti-inflammatory cytokine IL-10. Furthermore, the butyrate intervention ameliorated cisplatin-induced gut microbiota dysbiosis, preserving the structure and diversity of healthy microbial communities. Specifically, we observed a decrease in the abundance of Escherichia_Shigella and Blautia, alongside an increase in the abundance of the butyrate-producing genus Roseburia. Notably, Escherichia_Shigella exhibited a positive correlation with the pro-inflammatory factor MPO, while displaying a negative correlation with the anti-inflammatory cytokine IL-10. Butyrate also attenuated the cisplatin-induced expression of senescence markers p21 and p16 in kidney tissue. It alleviated the cisplatin-increased senescence-associated beta-galactosidase activity and reactive oxygen species production in SV40 MES-13 cells. These results indicate that butyrate, derived from the gut microbiota, may exert a protective effect against cisplatin-induced kidney damage by regulating microbiota balance and anti-inflammatory effects.

Advances in characterization of probiotics and challenges in industrial application

An unbalanced diet and poor lifestyle are common reasons for numerous health complications in humans. Probiotics are known to provide substantial benefits to human health by producing several bioactive compounds, vitamins, short-chain fatty acids and short peptides. Diets that contain probiotics are limited to curd, yoghurt, kefir, kimchi, etc. However, exploring the identification of more potential probiotics and enhancing their commercial application to improve the nutritional quality would be a significant step to utilizing the maximum benefits. The complex evolution patterns among the probiotics are the hurdles in their characterization and adequate application in the industries and dairy products. This article has mainly discussed the molecular methods of characterization that are based on the analysis of ribosomal RNA, whole genome, and protein markers and profiles. It also has critically emphasized the emerging challenges in industrial applications of probiotics.

Microbiota-derived butyrate inhibits cDC development via HDAC inhibition, diminishing their ability to prime T cells

Conventional dendritic cells (cDC) are central to maintaining the balance between protective immune responses and tolerance to harmless antigens, especially in the intestine. Short chain fatty acids (SCFAs) such as butyrate play critical roles in regulating intestinal immunity, but the underlying mechanisms remain unclear. Here we demonstrate that microbiota-derived butyrate alters intestinal cDC populations in vivo resulting in decreased numbers of the cDC2 lineage. By establishing a novel in vitro culture model, we show that butyrate has a direct and selective ability to repress the development of cDC2 from cDC precursors, an effect that is independent of G-protein coupled receptors (GPCRs) and is due to inhibition of histone deacetylase 3. Finally, cDC derived from pre-cDC in the presence of butyrate in vitro express lower levels of costimulatory molecules and have a decreased ability to prime naïve T cells. Together, our data show that butyrate affects the developmental trajectory of cDC, selectively repressing the cDC2 lineage and reducing their ability to stimulate T cells. These properties may help explain the ability of butyrate to maintain homeostasis in the intestine.

Gut microbiota profiling in injection drug users with and without HIV-1 infection in Puerto Rico

Introduction

The full extent of interactions between human immunodeficiency virus (HIV) infection, injection drug use, and the human microbiome is unclear. In this study, we examined the microbiomes of HIV-positive and HIV-negative individuals, both drug-injecting and non-injecting, to identify bacterial community changes in response to HIV and drug use. We utilized a well-established cohort of people who inject drugs in Puerto Rico, a region with historically high levels of injection drug use and an HIV incidence rate disproportionately associated with drug use.

Methods

Using amplicon-based 16S rDNA sequencing, we identified amplicon sequence variants (ASVs) that demonstrated significant variations in the composition of microbial communities based on HIV status and drug use.

Results and discussion

Our findings indicate that the HIV-positive group exhibited a higher abundance of ASVs belonging to the genera Prevotella, Alloprevotella, Sutterella, Megasphaera, Fusobacterium, and Mitsuokella. However, Bifidobacteria and Lactobacillus ASVs were more abundant in injectors than in non-injectors. We examined the effect of drug use on the gut microbiome in both HIV-infected and non-infected patients, and found that multiple drug use significantly affected the microbial community composition. Analysis of differential of bacterial taxa revealed an enrichment of Bifidobacterium spp., Faecalibacterium spp., and Lactobacillus spp. in the multiple drug-injecting group. However, in the non-injecting group, Parabacteroides spp., Prevotella spp., Paraprevotella spp., Sutterella spp., and Lachnoclostridium spp. The presence of multiple drug-injecting groups was observed to be more prevalent. Our findings provide detailed insight into ASV-level changes in the microbiome in response to HIV and drug use, suggesting that the effect of HIV status and drug injection may have different effects on microbiome composition and in modulating gut bacterial populations.

Modulation of gut microbiota in targeted cancer therapy: insights on the EGFR/VEGF/KRAS pathways

The rise in the incidence of cancer globally has led to a heightened interest in targeted therapies as a form of anticancer treatment. Key oncogenic targets, including epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), and kirsten rat sarcoma viral oncogene homologue (KRAS), have emerged as focal points in the development of targeted agents. Research has investigated the impact of gut microbiota on the efficacy of various anticancer therapies, such as immunotherapy, chemotherapy, and radiotherapy. However, a notable gap exists in the literature regarding the relationship between gut microbiota and targeted agents. This review emphasizes how specific gut microbiota and gut microbiota metabolites, including butyrate, propionate, and ursodeoxycholic acid, interact with oncogenic pathways to modulate anti-tumor effects. Conversely, deoxycholic acid, lipopolysaccharide, and trimethylamine n-oxide may exert pro-tumor effects. Furthermore, modulation of the gut microbiota influences glucose and lipid metabolism, thereby enhancing the response to anti-KRAS agents and addressing diarrhea induced by tyrosine kinase inhibitors. By elucidating the connection between gut microbiota and the EGFR/VEGF/KRAS pathways, this review provides valuable insights for advancing targeted cancer therapy and optimizing treatment outcomes in clinical settings.

Advancing microbiome research in Māori populations: insights from recent literature exploring the gut microbiomes of underrepresented and Indigenous peoples

The gut microbiome plays vital roles in human health, including mediating metabolism, immunity, and the gut-brain axis. Many ethnicities remain underrepresented in gut microbiome research, with significant variation between Indigenous and non-Indigenous peoples due to dietary, socioeconomic, health, and urbanization differences. Although research regarding the microbiomes of Indigenous peoples is increasing, Māori microbiome literature is lacking despite widespread inequities that Māori populations face. These inequities likely contribute to gut microbiome differences that exacerbate negative health outcomes. Characterizing the gut microbiomes of underrepresented populations is necessary to inform efforts to address health inequities. However, for microbiome research to be culturally responsible and meaningful, study design must improve to better protect the rights and interests of Indigenous peoples. Here, we discuss barriers to Indigenous participation in research and the role disparities may play in shaping the gut microbiomes of Indigenous peoples, with a particular focus on implications for Māori and areas for improvement.

Effect of Postbiotic Bifidobacterium longum CECT 7347 on Gastrointestinal Symptoms, Serum Biochemistry, and Intestinal Microbiota in Healthy Adults: A Randomised, Parallel, Double-Blind, Placebo-Controlled Pilot Study

OBJECTIVES

A randomised, double-blind, placebo-controlled pilot trial was conducted to assess the effect of heat-treated Bifidobacterium longum CECT 7347 (HT-ES1) in healthy adults with mild to moderate digestive symptoms. A total of 60 participants were recruited and received either HT-ES1 or an identical placebo for 8 weeks with a further follow-up at week 10.

METHODS

This study monitored changes in the total Gastrointestinal Symptom Rating Scale for IBS score (GSRS-IBS), Irritable Bowel Syndrome Symptom Severity Scale (IBS-SSS), IBS Quality of Life index (IBS-QoL), gut microbiome using 16S rRNA sequencing, and the Visceral Sensitivity Index, as well as a range of biochemical markers, anthropometric parameters, and adverse events.

RESULTS

While minimal changes were observed in gastrointestinal (GI) symptoms, the HT-ES1 group showed a significant decrease in total and non-HDL cholesterol compared to the placebo. The intervention group also exhibited a significant increase in the abundance of the genera Faecalibacterium and Anaerobutyricum, both of which were positively correlated with butyrate concentrations. Faecal calprotectin significantly increased over time in the placebo group but remained stable in the HT-ES1 group.

CONCLUSIONS

Overall, these findings suggest that HT-ES1 may promote gut health by increasing butyrate-producing bacteria in the gut, maintaining normal levels of faecal calprotectin and reducing serum cholesterol.

The Role of the Gut Microbiota in Individuals with Irritable Bowel Syndrome: A Scoping Review

Irritable bowel syndrome (IBS) represents the most prevalent disorder of brain-gut interaction, affecting approximately 10% of the global population. The objective of this study was to examine the mechanisms by which the gut microbiota contributes to the development of IBS. To this end, a review of articles that examined the gut microbiota of IBS patients was conducted. A search was conducted using PubMed and J-STAGE for articles published over the past five years that relate to the gut microbiota in patients with IBS. Individuals diagnosed with IBS display a reduction in alpha diversity and a decline in butyrate-producing bacteria, which collectively indicate a state of dysbiosis within their gut microbiota. Butyrate plays a dual role in the body, acting as a source of nutrition for the intestinal epithelium while also regulating the expression of dopamine transporters and D2 receptors in the central nervous system through epigenetic mechanisms. These characteristics may be linked to dysfunction of the central dopamine D2 pathway and play a role in the formation of various symptoms in IBS.

Fecal microbiota transplantation for glaucoma; a potential emerging treatment strategy

Glaucoma is the primary cause of irreversible blindness globally. Different glaucoma subtypes are identified by their underlying mechanisms, and treatment options differ by its pathogenesis. Current management includes topical medications to lower intraocular pressure and surgical procedures like trabeculoplasty and glaucoma drainage implants. Fecal microbiota transplantation (FMT) is an almost effective and safe treatment option for recurrent Clostridium difficile infection. The relationship between bacterial populations, metabolites, and inflammatory pathways in retinal diseases indicates possible therapeutic strategies. Thus, incorporating host microbiota-based therapies could offer an additional treatment option for glaucoma patients. Here, we propose that combining FMT with standard glaucoma treatments may benefit those affected by this condition. Also, the potential safety, efficacy, cost-effectiveness and clinical applications are discussed.

Aging and Pathological Conditions Similarity Revealed by Meta-Analysis of Metabolomics Studies Suggests the Existence of the Health and Age-Related Metapathway

Background: The incidence of many diseases increases with age and leads to multimorbidity, characterized by the presence of multiple diseases in old age. This phenomenon is closely related to systemic metabolic changes; the most suitable way to study it is through metabolomics. The use of accumulated metabolomic data to characterize this phenomenon at the system level may provide additional insight into the nature and strength of aging-disease relationships. Methods: For this purpose, metabolic changes associated with human aging and metabolic alterations under different pathological conditions were compared. To do this, the published results of metabolomic studies on human aging were compared with data on metabolite alterations collected in the human metabolome database through metabolite set enrichment analysis (MSEA) and combinatorial analysis. Results: It was found that human aging and pathological conditions involve the set of the same metabolic pathways with a probability of 99.96%. These data show the high identity of the aging process and the development of diseases at the metabolic level and allow to identify the set of metabolic pathways reflecting age-related changes closely associated with health. Based on these pathways, a metapathway was compiled, changes in which are simultaneously associated with health and age. Conclusions: The knowledge about the strength of the convergence of aging and pathological conditions has been supplemented by the rigor evidence at the metabolome level, which also made it possible to outline the age and health-relevant place in the human metabolism.

The Role of the Gut Microbiome in Kidney Stone Disease

Microbiome dysbiosis is closely related to the etiology of kidney stone disease (KSD) and influences a multitude of pathways. Due to our knowledge gaps on this topic, it is still unclear if microbiome interventions can be translated to demonstrate clinical efficacy. Current evidence suggests that the enhancement of butyrate-producing pathways should be the next step for KSD research. While we are not yet at a point where we can make clinical recommendations for KSD, there are many simple dietary or supplement-based approaches that could be applied in the future for prophylaxis or treatment of KSD.

Effects of poultry by-product meal and complete replacement of fish oil with alternative oils on growth performance and gut health of rainbow trout (Oncorhynchus mykiss): a FEEDNETICS™ validation study

BACKGROUND

Aquaculture, traditionally a form of biotechnology, has evolved to integrate innovative biotechnological applications, such as advanced feed formulations, aimed at improving the growth performance and health of farmed fish species. In the present study, the effects of feeding rainbow trout with novel feed formulations were investigated. Fish growth, gut and liver morphology, the concentration of fatty acids in the fillet, and volatile fatty acids in the gut were assessed. The study also validated scenarios from in vivo experiments using a nutrient-based model called FEEDNETICS™. This globally used model serves as a tool for data interpretation and decision support in the context of precision fish farming.

METHODS

Alternative protein and oil sources, including poultry by-product meal (PBM) and natural algae oil, were explored as sustainable replacements for fishmeal (FM) and fish oil (FO). A 90-day feeding trial was conducted using rainbow trout, comparing two isoproteic, isolipidic and isoenergetic diets. The control diet contained 15% FM, 5% PBM, and 8% FO, while the test diet replaced FM with 15% PBM and 5% feather meal hydrolysate (FMH), and fully substituted FO with VeraMaris® natural algae oil and rapeseed oil.

RESULTS

PBM successfully replaced FM protein without negatively affecting feed intake, growth performance or feed utilization in trout. The combination of PBM and natural algae oil was well tolerated by the trout and showed no negative effects on gut health. A detailed analysis of fatty acids in the fillet revealed that PUFAs of the n3 and n6 series were significantly higher in the PBM group than in the FM group. Values of fatty acid-related health indexes, including atherogenicity index, and thrombogenicity index, confirmed the high nutritional value of trout filet, thus representing a healthy product for human. In addition, the predictions using the FEEDNETICS™ indicated that the tested novel alternative formulations are economically viable. The validation of the model for fish growth resulted in a Mean Absolute Percentage Error (MAPE) of 8%.

CONCLUSIONS

The FEEDNETICS™ application enhances our ability to optimize feeding strategies and improve production efficiency in the aquaculture industry. VeraMaris® algae oil and PBM could serve as viable and sustainable raw materials for fish feed, promoting environmentally friendly aquaculture practices.

Butyrate as a growth factor of Clostridium acetobutylicum

The butyrate biosynthetic pathway not only contributes to electron management and energy generation in butyrate forming bacteria, but also confers evolutionary advantages to the host by inhibiting the growth of surrounding butyrate-sensitive microbes. While high butyrate levels induce toxic stress, effects of non-toxic levels on cell growth, health, metabolism, and sporulation remain unclear. Here, we show that butyrate stimulates cellular processes of Clostridium acetobutylicum, a model butyrate forming Firmicute. First, we deleted the 3-hydroxybutyryl-CoA dehydrogenase gene (hbd) from the C. acetobutylicum chromosome to eliminate the butyrate synthetic pathway and thus butyrate formation. A xylose inducible Cas9 cassette was chromosomally integrated and utilized for the one-step markerless gene deletions. Non-toxic butyrate levels significantly affected growth, health, and sporulation of C. acetobutylicum. After deleting spo0A, the gene encoding the master regulator of sporulation, Spo0A, and conducting butyrate addition experiments, we conclude that butyrate affects cellular metabolism through both Spo0A-dependent and independent mechanisms. We also deleted the hbd gene from the chromosome of the asporogenous C. acetobutylicum M5 strain lacking the pSOL1 plasmid to examine the potential involvement of pSOL1 genes on the observed butyrate effects. Addition of crotonate, the precursor of butyrate biosynthesis, to the hbd deficient M5 strain was used to probe the role of butyrate biosynthesis pathway in electron and metabolic fluxes. Finally, we found that butyrate addition can enhance the growth of the non-butyrate forming Clostridium saccharolyticum. Our data suggest that butyrate functions as a stimulator of cellular processes, like a growth factor, in C. acetobutylicum and potentially evolutionarily related Clostridium organisms.

A Sustained-Release Butyrate Tablet Suppresses Ex Vivo T Helper Cell Activation of Osteoarthritis Patients in a Double-Blind Placebo-Controlled Randomized Trial

Degenerative joint disease osteoarthritis (OA) is characterized by the degeneration of cartilage, synovial inflammation and low-grade systemic inflammation in association with microbial dysbiosis and intestinal barrier defects. Butyrate is known for its anti-inflammatory and barrier protective effects and might benefit OA patients. In a double-blind placebo-controlled randomized trial, the effects of four to five weeks of oral treatment with sustained-release (SR) butyrate tablets (600 mg/day) on systemic inflammation and immune function were studied in hand OA patients. Serum markers for systemic inflammation and lipopolysaccharide (LPS) leakage were measured and ex vivo stimulation of whole blood or peripheral blood mononuclear cells (PBMCs) was performed at baseline and after treatment. Butyrate treatment did not affect the serum markers nor the cytokine release of ex vivo LPS-stimulated whole blood or PBMCs nor the phenotype of restimulated monocytes. By contrast, butyrate treatment reduced the percentage of activated T helper (Th) cells and the Th17/Treg ratio in αCD3/CD28-activated PBMCs, though cytokine release upon stimulation remained unaffected. Nevertheless, the percentage of CD4+IL9+ cells was reduced by butyrate as compared to the placebo. In both groups, the frequency of Th1, Treg, Th17, activated Th17, CD4+IFNγ+ and CD4+TNFα+ cells was reduced. This study shows a proof of principle of some immunomodulatory effects using a SR butyrate treatment in hand OA patients. The inflammatory phenotype of Th cells was reduced, as indicated by a reduced percentage of Th9 cells, activated Th cells and improved Th17/Treg balance in ex vivo αCD3/CD28-activated PBMCs. Future studies are warranted to further optimize the butyrate dose regime to ameliorate inflammation in OA patients.