The gut microbiota, bacterial metabolites and colorectal cancer

Role of gut microbiome in suppression of cancers

The pathogenesis of cancer is closely related to the disruption of homeostasis in the human body. The gut microbiome plays crucial roles in maintaining the homeostasis of its host throughout lifespan. In recent years, a large number of studies have shown that dysbiosis of the gut microbiome is involved in the entire process of cancer initiation, development, and prognosis by influencing the host immune system and metabolism. Some specific intestinal bacteria promote the occurrence and development of cancers under certain conditions. Conversely, some other specific intestinal bacteria suppress the oncogenesis and progression of cancers, including inhibiting the occurrence of cancers, delaying the progression of cancers and boosting the therapeutic effect on cancers. The promoting effects of the gut microbiome on cancers have been comprehensively discussed in the previous review. This article will review the latest advances in the roles and mechanisms of gut microbiome in cancer suppression, providing a new perspective for developing strategies of cancer prevention and treatment.

The stems and leaves of Panax notoginseng reduce the abundance of antibiotic resistance genes by regulating intestinal microbiota in Duzang pigs

In order to study the distribution characteristics of intestinal microbiota and antibiotic resistance genes (ARGs) in Duzang pigs after adding stems and leaves of Panax notoginseng to the feed, the characteristics of intestinal microbiota were explored by metagenomic sequencing, and 14 ARGs and 2 integrase genes were detected by qPCR. The results showed that the addition of stems and leaves of P. notoginseng increased the relative abundance of Firmicutes, Lactobacillus and Pediococcus in the cecum of Duzang pigs. A total of 10 ARGs and 2 integrase genes were detected in the cecal contents of pigs. The addition of stems and leaves of P. notoginseng reduced the relative abundance of total ARGs, ermB, tetO and tetW in the cecum of Duzang pigs. The results of network analysis showed that multiple genera were potential hosts of ARGs. The addition of stems and leaves of P. notoginseng may reduce the relative abundance of ARGs by reducing the relative abundance of genera such as Corynebacterium and Flavonifractor, thereby reducing the risk of ARGs spread. This study provides a theoretical basis for the rational use of stems and leaves of P. notoginseng to control ARGs.

Novel insights into carbohydrate utilisation, antimicrobial resistance, and sporulation potential in Roseburia intestinalis isolates across diverse geographical locations

Roseburia intestinalis is one of the most abundant and important butyrate-producing human gut anaerobic bacteria that plays an important role in maintaining health and is a potential next-generation probiotic. We investigated the pangenome of 16 distinct strains, isolated over several decades, identifying local and time-specific adaptations. More than 50% of the genes in each individual strain were assigned to the core genome, and 77% of the cloud genes were unique to individual strains, revealing the high level of genome conservation. Co-carriage of the same enzymes involved in carbohydrate binding and degradation in all strains highlighted major pathways in carbohydrate utilization and reveal the importance of xylan, starch and mannose as key growth substrates. A single strain had adapted to use rhamnose as a sole growth substrate, the first time this has been reported. The ubiquitous presence of motility and sporulation gene clusters demonstrates the importance of these phenotypes for gut survival and acquisition of this bacterium. More than half the strains contained functional, potentially transferable, tetracycline resistance genes. This study advances our understanding of the importance of R. intestinalis within the gut ecosystem by elucidating conserved metabolic characteristics among different strains, isolated from different locations. This information will help to devise dietary strategies to increase the abundance of this species providing health benefits.

Microbiota and metabolite-based prediction tool for colonic polyposis with and without a known genetic driver

Despite extensive investigations into the microbiome and metabolome changes associated with colon polyps and colorectal cancer (CRC), the microbiome and metabolome profiles of individuals with colonic polyposis, including those with (Gene-pos) and without (Gene-neg) a known genetic driver, remain comparatively unexplored. Using colon biopsies, polyps, and stool from patients with Gene-pos adenomatous polyposis (N = 9), Gene-neg adenomatous polyposis (N = 18), and serrated polyposis syndrome (SPS, N = 11), we demonstrated through 16S rRNA sequencing that the mucosa-associated microbiota in individuals with colonic polyposis is representative of the microbiota associated with small polyps, and that both Gene-pos and SPS cohorts exhibit differential microbiota populations relative to Gene-neg polyposis cohorts. Furthermore, we used these differential microbiota taxa to perform linear discriminant analysis to differentiate Gene-neg subjects from Gene-pos and from SPS subjects with an accuracy of 89% and 93% respectively. Stool metabolites were quantified via 1H NMR, revealing an increase in alanine in SPS subjects relative to non-polyposis subjects, and Partial Least Squares Discriminant Analysis (PLS-DA) analysis indicated that the proportion of leucine to tyrosine in fecal samples may be predictive of SPS. Use of these microbial and metabolomic signatures may allow for better diagnostric and risk-stratification tools for colonic polyposis patients and their families as well as promote development of microbiome-targeted approaches for polyp prevention.

Exploring preventive and treatment strategies for oral cancer: Modulation of signaling pathways and microbiota by probiotics

The evidence suggests that the microbiome plays a crucial role in cancer development. The oral cavity has many microorganisms that can influence oral cancer progression. Understanding the mechanisms and signaling pathways of the oral, gum, and teeth microbiome in tumor progression can lead to new treatment strategies. Probiotics, which are friendly microorganisms, have shown potential as anti-cancer agents. These positive characteristics of probiotic strains make them suitable for cancer prevention or treatment. The oral-gut microbiome axis supports health and homeostasis, and imbalances in the oral microbiome can disrupt immune signaling pathways, epithelial barriers, cell cycles, apoptosis, genomic stability, angiogenesis, and metabolic processes. Changes in the oral microbiome in oral cancer may suggest using probiotics-based treatments for their direct or indirect positive roles in cancer development, progression, and metastasis, specifically oral squamous cell carcinoma (OSCC). Here, reported relationships between probiotics, oral microbiota, and oral cancer are summarized.

Fermentation characteristics of pectin-derived oligosaccharides from enzyme treated side streams of citrus processing

This study explored the conversion of citrus juice side streams into fermentable oligosaccharides for potential gut health benefits. Alcohol washed, insoluble lemon peel waste was enzymatically treated using technical pectinolytic enzyme preparations, yielding mixtures of galactose- arabinose- and either methyl-esterified or non-methyl-esterified galacturonic acid oligosaccharides (OS) with a Δ4,5-unsaturated non-reducing end resulting in mixtures of pectin-derived OS: POS and POSNME. Both mixtures were completely fermented during in vitro batch fermentation by proximal and distal microbiota of three healthy adult donors. Fermentation by distal and proximal microbiota resulted in similar methyl-ester-dependent mechanisms of POS utilization, yielding health beneficial acetate, propionate and butyrate in significant amounts. Arabinose-, galactose- and non-methyl-esterified Δ4,5-unsaturated galacturonic acid OS were utilized significantly faster by the distal and proximal microbiota of donors 1 and 2 compared to methyl-esterified Δ4,5-unsaturated galacturonic acid OS, suggesting methyl-esterification of Δ4,5-unsaturated galacturonic acid oligosaccharides as a substantial regulator of POS fermentability. The findings presented in this manuscript suggest that carbohydrate molecular structure and availability, rather than microbiota composition, determine carbohydrate fermentation patterns along the colon, emphasizing that the consumption of differently fermentable fiber is essential to promote gut health along the colon.

Causal relationship between gut microbiota and laryngeal cancer: a mendelian randomization analysis

OBJECTIVE

Laryngeal cancer incidence is rising globally; the role of gut microbiota remains underexplored. This study aimed to establish a causal link between gut microbiota and laryngeal cancer to inform preventive and therapeutic strategies.

METHODS

Gut microbiota data from GWAS conducted by the MiBioGen consortium served as the exposure variable, with laryngeal cancer as the outcome variable. the exposure variable and the outcome variable were analyzed using Mendelian Randomization. The primary method was Inverse Variance Weighted analysis, with heterogeneity and pleiotropy assessed through Cochran's Q test, MR-Egger regression, and MR-PRESSO.

RESULTS

In the study, we identified five bacterial taxa with potential causal relationships with laryngeal cancer risk: Higher levels of Clostridiaceae1 (OR = 0.9993, 95% CI 0.9986-0.9999, p = 0.0463) and Turicibacter (OR = 0.9995, 95% CI 0.9989-0.9999, p = 0.0384) were linked to reduced cancer risk, while Mollicutes RF9 (OR = 1.0010, 95% CI 1.0003-1.0016, p = 0.0027), Euryarchaeota (OR = 1.0004, 95% CI 1.0001-1.0007, p = 0.0234), and Cyanobacteria (OR = 1.0005, 95% CI 1.0000-1.0009, p = 0.0464) were associated with increased risk.

CONCLUSION

Our findings suggest a causal relationship between gut microbiota composition and laryngeal cancer risk. Clostridiaceae1 and Turicibacter may play a protective role, while Mollicutes RF9, Euryarchaeota, and Cyanobacteria could contribute to increased cancer susceptibility. These insights highlight potential microbiome-based strategies for early detection, prevention, and therapeutic intervention in laryngeal cancer.

LEVEL OF EVIDENCE

Level 5.

Gut microbiome links obesity to type 2 diabetes: insights from Mendelian randomization

BACKGROUND

Research has established links between the gut microbiome (GM) and both obesity and type 2 diabetes (T2D), which is much discussed, but underexplored. This study employed body mass index (BMI) as the measurement of obesity to delve deeper into the correlations from a genetic perspective.

METHODS

We performed the Mendelian randomization (MR) analysis to examine the causal effects of GM on T2D and BMI, and vice versa. Genome-wide association study (GWAS) summary datasets were utilized for the analysis, including T2D (N = 933,970), BMI (N = 806,834), and two GM datasets from the international consortium MiBioGen (211 taxa, N = 18,340) and the Dutch Microbiome Project (DMP) (207 taxa, N = 7,738). These datasets mainly cover European populations, with additional cohorts from Asia and other regions. To further explore the potential mediating role of GM in the connections between BMI and T2D, their interaction patterns were summarized into a network.

RESULTS

MR analysis identified 9 taxa that showed protective properties against T2D. Seven species were within the Firmicutes and Bacteroidales phyla in the DMP, and two were from the MiBioGen (Odds Ratio (OR): 0.94-0.95). Conversely, genetic components contributing to the abundance of 12 taxa were associated with increased risks of T2D (OR: 1.04-1.12). Furthermore, T2D may elevate the abundance of seven taxa (OR: 1.03-1.08) and reduce the abundance of six taxa (OR: 0.93-0.97). In the analysis of the influence of the genetic component of BMI on GM composition, BMI affected 52 bacterial taxa, with 28 decreasing (OR: 0.75-0.92) and 24 increasing (OR: 1.08-1.27). Besides, abundances of 25 taxa were negatively correlated with BMI (OR: 0.95-0.99), while positive correlations were detected for 14 taxa (OR: 1.01-1.05). Notably, we uncovered 11 taxa genetically associated with both BMI and T2D, which formed an interactive network.

CONCLUSIONS

Our findings provide evidence for the GM-mediated links between obesity and T2D. The identification of relevant GM taxa offers valuable insights into the potential role of the microbiome in these diseases.

Metagenomic Insights into the Rumen Microbiome in Solid and Liquid Fractions of Yaks and their Differences Compared to Other Ruminants

The rumen microbiome plays a critical role in nutrient metabolism and adaptation of the yak (Bos grunniens), an import livestock animal of the Qinghai-Tibet Plateau renowned for their superior plant fiber degradation capacity. However, the microbiome among the different ecological niches within yak's rumen remains unelucidated. Through shotgun sequencing of rumen solid and liquid fractions from five yaks, we identified significant differences in the microbial communities and their genetic functions between the solid and liquid fractions. Solid fractions exhibited dominance by Ruminococcus, Succiniclasticum, and Aspergillus, while Prevotella, Paludibacter, Parabacteroides, and Bacteroides prevailed in liquid fractions. Comparative CAZyme profiling revealed solid fractions were significantly enriched in cellulose/hemicellulose-targeting enzymes (GH5, GH11, and CBM63), implicating their specialization in breaking down the fibrous grasses. In contrast, liquid fractions showed higher abundances of starch-degrading enzymes (GH13, CBM48) and host-glycan utilizers (GH92), suggesting roles in soluble nutrient extraction and host-microbe interactions. Comparative analysis of 574 metagenome-assembled genomes suggested that Methanomethylophilaceae_UBA71 and nitrate-respiring Ruminococcaceae_Firm-04 preferentially colonized in the solids, whereas propionate-producing Quinella and animal glycan-degrading Bacteroides were more prevalent in the liquids. Moreover, compared to Hu sheep, yak's rumen microbiome showed significantly enhanced utilization of plant polysaccharide capacity. Comparative analysis across 10 ruminant species further highlighted host phylogeny as a key driver of rumen microbiome variation. These findings advance our understanding of niche differentiation and functional specialization within the unique yak rumen ecosystem.

The single degree of polymerization influences the efficacy of xylooligosaccharides in shaping microbial and metabolite profiles in chicken gut to combat avian pathogenic Escherichia coli

BACKGROUND

Avian pathogenic Escherichia coli (APEC) threatens both poultry production and human health. Xylooligosaccharides (XOS) may suppress pathogenic bacteria through prebiotic actions. However, the influences of single degree of polymerization (DP) on the inhibition of APEC by XOS remain unknown. This study aimed to probe if XOS and their major monomers (xylobiose, xylotriose and xylotetraose) could differentially combat APEC via prebiotic actions using an in vitro fermentation model with chicken cecal microbiota.

METHODS

Microbiota were randomly divided into 7 groups (5 replicate tubes/group). Control group (CON) received no treatment; XOS group received commercial XOS mixtures; APEC group received APEC; XA, X2, X3 and X4 groups received APEC combined with commercial XOS mixtures, xylobiose, xylotriose and xylotetraose, respectively.

RESULTS

XOS and their major monomers mitigated APEC-induced decline (p < 0.05) in gut microbial α-diversity, with xylotetrose showing the least effect. Gut microbiota in XA, X2, X3 and X4 groups clustered together, with a relative separation observed in X4 group. XOS and their monomers elevated (p < 0.05) the abundances of Firmicutes, Bacteroidota and several probiotics (Lactobacillus, Bacteroides and Megamonas), but reduced (p < 0.05) the abundances of Proteobacteria and Escherichia-Shigella, with xylotetraose exhibiting the least efficacy. Besides, xylotriose and xylotetrose had an advantage over xylotetraose in promoting microbial production of short-chain fatty acids. Metabolomics analysis revealed that APEC challenge mainly downregulated (p < 0.05) several amino acids metabolism pathways of gut microbiota, while xylotriose had an inferiority to XOS in upregulating (p < 0.05) histidine metabolism pathway. Furthermore, microbial fermentation metabolites of all XOS monomers lowered (p < 0.05) certain virulence genes expression in APEC, with xylotriose being the most advantageous.

CONCLUSIONS

XOS and their major monomers differentially improved gut microbiota and metabolite profiles in chicken gut against APEC challenge. Overall, xylotriose exhibited the greatest inhibition against APEC abundance and virulence. Our findings underscore the role of single DP in influencing the prebiotic actions of XOS against APEC, providing a basis for the reasonable application of XOS in diets to combat bacterial challenge.

The Microbiota-Human Health Axis

Trillions of microorganisms play a pivotal role in maintaining health and preventing disease in humans. Their presence influences daily life, habits, energy levels, and pathologies. The present narrative review synthesized recent studies of microbial diversity across organ systems. The composition of the microbiota regulates the intestinal barrier, modulates the immune response, influences metabolism, and produces essential compounds such as short-chain fatty acids and neurotransmitters. Dysbiosis is associated with numerous pathologies, including metabolic, autoimmune, neurodegenerative, and cardiovascular diseases. The microbiota is key to maintaining physiological balance and reducing disease risk. Therapeutic interventions, such as probiotics, prebiotics, postbiotics, and microbiome transplantation, offer promising perspectives in restoring microbial homeostasis and preventing chronic diseases.

Ultrasonic degradation of mulberry twigs polysaccharides: Effect on in vitro hypoglycemic activity and prebiotic potential

This study aimed to enhance the in vitro hypoglycemic activity of mulberry twigs polysaccharides (MTP) through ultrasonic degradation and to elucidate its underlying mechanisms and prebiotic potential. The results demonstrated that ultrasonic degradation effectively increased its inhibitory activity against α-glucosidase. Structural characterization of MTP revealed that ultrasonic degradation significantly decreasing its molecular weight and monosaccharide composition. Mechanistic studies indicated that the inhibition of α-glucosidase by the degraded product MTP-240 was reversible and followed a single static quenching process. In vitro fermentation assays revealed that MTP-240 promoted the production of short-chain fatty acids (SCFAs), surpassing the inulin control, with pentanoic acid accumulating most substantially. Additionally, MTP-240 enhanced the growth of Bifidobacterium, a beneficial gut bacterium associated with improved glucose levels and antioxidant capacity. These findings suggested that ultrasonic degradation was an effective method for enhancing the glycosidase inhibitory activity of polysaccharides, and the degraded MTP possesses the potential to be developed as a food additive with dual functions of glycosidase inhibition and prebiotic activity. This research provides a theoretical basis for the further development of mulberry resources and related functional foods.

Effect of bacteriocin RSQ01 on milk microbiota during pasteurized milk preservation

Milk has high risk for microbial contamination. RSQ01, a bacteriocin, previously has shown potentiality for pasteurized milk preservation. This study analyzed the effects of RSQ01 on milk microbiota by comparison of bacterial number and composition in 3 pasteurized milk groups: controls without RSQ01, treatment group with the addition of 2 × MIC (low concentration) and 4 × MIC RSQ01 (high concentration). Integrated 16S rDNA sequencing and metagenomics of these groups after 3 d of storage showed inhibition of RSQ01 on microbiota diversity. Pathogenic bacteria such as Salmonella showed a decrease in relative abundance after RSQ01 treatment, while probiotic bacteria such as Lactococcus showed an increase, indicating that RSQ01 contributed to milk preservation by maintaining a low abundance of pathogens and a relatively high abundance of probiotics. Further investigations revealed that milk preservation was primarily attributed to the ability of RSQ01 to decrease the relative abundance of genes related to metabolism of energy and nutrients (e.g., vitamins, lipids, and amino acids) of microbiota, with change of genetic, environmental, and cellular processes. Interestingly, RSQ01 generally reduced the relative abundance of virulence factors- and quorum-sensing-related genes in microbiota, likely reducing virulence and resistance. The findings provided insights into microbiomics mechanisms regarding pasteurized milk preservation of bacteriocins.

Integrating microbial GWAS and single-cell transcriptomics reveals associations between host cell populations and the gut microbiome

Microbial genome-wide association studies (GWAS) have uncovered numerous host genetic variants associated with gut microbiota. However, links between host genetics, the gut microbiome and specific cellular contexts remain unclear. Here we use a computational framework, scBPS (single-cell Bacteria Polygenic Score), to integrate existing microbial GWAS and single-cell RNA-sequencing profiles of 24 human organs, including the liver, pancreas, lung and intestine, to identify host tissues and cell types relevant to gut microbes. Analysing 207 microbial taxa and 254 host cell types, scBPS-inferred cellular enrichments confirmed known biology such as dominant communications between gut microbes and the digestive tissue module and liver epithelial cell compartment. scBPS also identified a robust association between Collinsella and the central-veinal hepatocyte subpopulation. We experimentally validated the causal effects of Collinsella on cholesterol metabolism in mice through single-nuclei RNA sequencing on liver tissue to identify relevant cell subpopulations. Mechanistically, oral gavage of Collinsella modulated cholesterol pathway gene expression in central-veinal hepatocytes. We further validated our approach using independent microbial GWAS data, alongside single-cell and bulk transcriptomic analyses, demonstrating its robustness and reproducibility. Together, scBPS enables a systematic mapping of the host-microbe crosstalk by linking cell populations to their interacting gut microbes.

Gut microbiota contributes to protection against porcine deltacoronavirus infection in piglets by modulating intestinal barrier and microbiome

BACKGROUND

Gut microbiota plays a critical role in counteracting enteric viral infection. Our previous study demonstrated that infection of porcine deltacoronavirus (PDCoV) disturbs gut microbiota and causes intestinal damage and inflammation in piglets. However, the influence of gut microbiota on PDCoV infection remains unclear.

RESULTS

Firstly, the relationship between gut microbiota and disease severity of PDCoV infection was evaluated using 8-day-old and 90-day-old pigs. The composition of gut microbiota was significantly altered in 8-day-old piglets after PDCoV infection, leading to severe diarrhea and intestinal damage. In contrast, PDCoV infection barely affected the 90-day-old pigs. Moreover, the diversity (richness and evenness) of microbiota in 90-day-old pigs was much higher compared to the 8-day-old piglets, suggesting the gut microbiota is possibly associated with the severity of PDCoV infection. Subsequently, transplanting the fecal microbiota from the 90-day-old pigs to the 3-day-old piglets alleviated clinical signs of PDCoV infection, modulated the diversity and composition of gut microbiota, and maintained the physical and chemical barrier of intestines. Additionally, metabolomic analysis revealed that the fecal microbiota transplantation (FMT) treatment upregulated the swine intestinal arginine biosynthesis, FMT significantly inhibited the inflammatory response in piglet intestine by modulating the TLR4/MyD88/NF-κB signaling pathway.

CONCLUSIONS

PDCoV infection altered the structure and composition of the gut microbiota in neonatal pigs. FMT treatment mitigated the clinical signs of PDCoV infection in the piglets by modulating the gut microbiota composition and intestinal barrier, downregulating the inflammatory response. The preventive effect of FMT provides novel targets for the development of therapeutics against enteropathogenic coronaviruses. Video Abstract.

Effects of Long-Term Airport Noise Exposure on Inflammation and Intestinal Flora and Their Metabolites in Mice

Background: The World Health Organization has indicated that airport noise is strongly associated with cardiovascular disease, with vascular inflammation identified as the primary mechanism. Therefore, long-term exposure to airport noise is considered far more harmful than other types of noise. However, there remains a lack of research into the mechanisms underlying long-term exposure to airport noise and harm to the human body. Methods: A mouse model was established and exposed to airport noise at a maximum sound pressure level of 95 dB(A) and an equivalent continuous sound pressure level of 72 dB(A) for 12 h per day over a period of 100 days. Quantitative polymerase chain reaction (qPCR) was used to detect the mRNA expression levels of pro-inflammatory and anti-inflammatory factors. Enzyme-linked immunosorbent assay (ELISA) was used to detect LPS, LTA, TMA, and TMAO levels. Intestinal flora composition was analyzed by 16S rDNA sequencing, and targeted metabolomics was employed to determine the levels of serum short-chain fatty acids. Results: Long-term airport noise exposure significantly increased systolic blood pressure, diastolic blood pressure, and mean blood pressure (p < 0.05); significantly increased the mRNA expression levels of oxidative stress parameters (nuclear matrix protein 2, 3-nitrotyrosine, and monocyte chemoattractant protein-1) (p < 0.05); significantly increased pro-inflammatory factors (interleukin 6 and tumor necrosis factor alpha) (p < 0.05); significantly decreased the mRNA expression level of anti-inflammatory factor interleukin 10 (p < 0.05); and significantly increased the content of LPS and LTA (p < 0.05). The composition of the main flora in the intestinal tract was structurally disordered, and there were significant differences between the noise-exposed and control groups at the levels of the phylum, family, and genus of bacteria. β-diversity of the principal component analysis diagrams was clearly distinguished. Compared with those of the control group, TMA-producing bacteria and levels of TMA and TMAO were significantly reduced, and the serum ethanoic acid and propanoic acid levels of the noise-exposed group were significantly decreased (p < 0.05). Conclusions: Long-term airport noise exposure causes significant elevation of blood pressure and structural disruption in the composition of the intestinal flora in mice, leading to elevated levels of oxidative stress and inflammation, resulting in metabolic disorders that lead to significant changes in the production of metabolites.

Polymer-lipid hybrid microcarriers for oral codelivery of paclitaxel and tributyrin: development, optimization, and cytotoxicity in cells and spheroids of colorectal cancer

Colorectal cancer (CRC) is the third most frequent cancer worldwide. Despite advances in treatment, conventional chemotherapy suffers from severe side effects and limited drug selectivity, highlighting the importance of alternative therapies. In this study, a polymer-lipid hybrid microcarrier was developed for oral co-administration of paclitaxel (PTX) and tributyrin (TB) as a novel approach for CRC therapy. The microcarrier was designed with a pH-sensitive polymeric shell that encapsulates drug-loaded nanostructured lipid carriers (NLC); shell dissolution at intestinal pH enables localized release of the NLC. The methodological approach employed an emulsion of vegetable oil and NLC as a template for polymer deposition. Multiple parameters were optimized, including polymers ratios, NLC dilution, acid concentration, and sonication time. Spherical hybrid particles with smooth surface and mean size of 1000 nm were obtained; PTX encapsulation efficiency was 99.9 ± 0.2 %, with a production yield of 97.2 ± 0.08 %. Drug release followed the Korsmeyer-Peppas kinetic model. Cytotoxic evaluation in human colorectal adenocarcinoma HCT-116 monolayers showed that PTX encapsulation increased cytotoxicity, lowering IC50 to 83.7 nM compared to 199.5 nM for free PTX. The addition of TB further improved cytotoxicity, reducing the IC50 to 60.8 nM. A similar potentiation cytotoxicity was observed in spheroids. The microcarrier induced reductions in colony formation, alterations in cell cytoskeleton, and led to a significant reduction in P-glycoprotein expression compared to its free form, suggesting its potential to help to overcome drug resistance. These results point to the promising applicability of the hybrid microcarrier as an innovative delivery system for oral administration of cytotoxic agents.

Age-related dynamics of predominant methanogenic archaea in the human gut microbiome

BACKGROUND

The reciprocal relationship between aging and alterations in the gut microbiota is a subject of ongoing research. While the role of bacteria in the gut microbiome is well-documented, specific changes in the composition of methanogens during extreme aging and the impact of high methane production in general on health remain unclear. This study was designed to explore the association of predominant methanogenic archaea within the human gut and aging.

METHODS

Shotgun metagenomic data from the stool samples of young adults (n = 127, Age: 19-59 y), older adults (n = 86, Age: 60-99 y), and centenarians (n = 34, age: 100-109 years) were analyzed.

RESULTS

Our findings reveal a compelling link between age and the prevalence of high methanogen phenotype, while overall archaeal diversity diminishes. Surprisingly, the archaeal composition of methanogens in the microbiome of centenarians appears more akin to that of younger adults, showing an increase in Methanobrevibacter smithii, rather than Candidatus Methanobrevibacter intestini. Remarkably, Ca. M. intestini emerged as a central player in the stability of the archaea-bacteria network in adults, paving the way for M. smithii in older adults and centenarians. Notably, centenarians exhibit a highly complex and stable network of these two methanogens with other bacteria. The mutual exclusion between Lachnospiraceae and these methanogens throughout all age groups suggests that these archaeal communities may compensate for the age-related drop in Lachnospiraceae by co-occurring with Oscillospiraceae.

CONCLUSIONS

This study underscores the dynamics of archaeal microbiome in human physiology and aging. It highlights age-related shifts in methanogen composition, emphasizing the significance of both M. smithii and Ca. M. intestini and their partnership with butyrate-producing bacteria for potential enhanced health.

Microbiome and biofilm insights from normal vs tumor tissues in Thai colorectal cancer patients

Colorectal cancer (CRC) is a prevalent global malignancy with complex etiologies, including microbiota alterations. This study investigates gut microbiota and biofilm-producing bacteria in 35 Thai CRC patients, analyzing paired normal and tumor biopsy samples. Bacterial DNA from the V3-V4 region of 16S rRNA was sequenced, and biofilms were visualized via scanning electron microscopy and fluorescence in situ hybridization (FISH). Results revealed Firmicutes as the dominant phylum, followed by Bacteroidota, Proteobacteria, and Fusobacteriota, with Fusobacteriota and Bacteroidota notably enriched in left-sided CRC. Key biofilm producers-Bacteroides fragilis, Fusobacterium nucleatum, and Pasteurella stomatis-showed significantly higher gene expression in tumor tissues. Dense biofilms and higher Fusobacterium abundance, localized within the crypts of Lieberkuhn, were observed in CRC tissues. These findings highlight CRC-associated microbiota alterations and pathogenic biofilm production, emphasizing a spatial relationship between tumor location and microbial distribution, with potential implications for understanding CRC pathogenesis and therapeutic targeting.

Decoding the link between microbial secondary metabolites and colorectal cancer

Colorectal cancer (CRC) is a prevalent form of cancer in humans, with the gut microbiota playing a significant role in its pathogenesis. Although previous research has primarily focused on the role of primary metabolites produced by gut microbes in CRC development, the role of secondary metabolites remains largely unexplored. Secondary metabolites are known to mediate crucial interactions between the microbiota and the host, potentially influencing CRC progression. However, their specific relationship to CRC pathogenesis is poorly understood. To address this gap, we performed a meta-analysis using fecal metagenomic data from a cohort of CRC patients and healthy controls, aiming to identify CRC-associated microbial secondary metabolite biosynthetic gene clusters (BGCs). Our findings not only provide valuable insights into the pathogenicity and carcinogenicity of CRC but also shed light on the potential mechanisms underlying its development.

Combining gut microbiota modulation and immunotherapy: A promising approach for treating microsatellite stable colorectal cancer

Colorectal cancer (CRC) is one of the most prevalent and lethal cancers worldwide, ranking third in incidence and second in mortality. While immunotherapy has shown promise in patients with deficient mismatch repair (dMMR) or high microsatellite instability (MSI-H), its effectiveness in proficient mismatch repair (pMMR) or microsatellite stable (MSS) CRC remains limited. Recent advances highlight the gut microbiota as a potential modulator of anti-tumor immunity. The gut microbiome can significantly influence the efficacy of immune checkpoint inhibitors (ICIs), especially in pMMR/MSS CRC, by modulating immune responses and systemic inflammation. This review explores the role of the gut microbiota in pMMR/MSS CRC, the mechanisms by which it may enhance immunotherapy, and current strategies for microbiota modulation. We discuss the potential benefits of combining microbiota-targeting interventions with immunotherapy to improve treatment outcomes for pMMR/MSS CRC patients.

Characterization of diet-linked amino acid pool influence on Fusobacterium spp. growth and metabolism

The genus Fusobacterium contains multiple proteolytic opportunistic pathogens that have been increasingly linked to colorectal cancer (CRC). "Oncomicrobes" such as these fusobacterial species within the gut microbiota may contribute to CRC onset and/or progression. Protein-rich diets may both directly increase CRC risk and enrich for proteolytic oncomicrobes, including Fusobacterium spp. Individual food substrates vary in amino acid content, and released amino acid content that is not absorbed in the small intestine may influence the growth of colonic proteolytic fermenters. Fusobacteria such as Fusobacterium spp. are known to preferentially metabolize certain amino acids. As such, some foods may better support the growth of these species within the colonic environment than others. To explore this, in this study, we created free amino acid pools (FAAPs) to represent proportions of amino acids in major proteins of three common dietary protein sources (soy, beef, and bovine milk). Growth curves were generated for 39 Fusobacterium spp. strains cultured in a dilute medium supplemented with each of the three FAAPs. Thereafter, amino acid use by 31 of the 39 Fusobacterium spp. strains in each FAAP treatment was assessed. FAAP supplementation increased growth metrics of all Fusobacterium spp. strains tested; however, the strains varied greatly in terms of the FAAP(s) generating the greatest increase in growth. Furthermore, the amino acid utilization strategy was highly variable between strains of Fusobacterium spp. Neither growth metrics nor amino acid utilization could be explained by species classification of Fusobacterium spp. strains. This report expands upon the previous knowledge of fusobacterial amino acid metabolism and indicates that proteolytic oncomicrobial activity should be assessed in the context of available protein sources.IMPORTANCEFusobacterium spp. including F. animalis, F. nucleatum, F. vincentii, and F. polymorphum are common oral commensals with emerging importance in diseases across multiple body sites, including CRC. CRC lesions associated with fusobacteria tend to result in poorer prognosis and increased disease recurrence. While Fusobacterium spp. are thought to colonize after tumorigenesis, little is known about the factors that facilitate this colonization. Protein-rich diets yielding readily metabolized free amino acids within the colon may promote the growth of proteolytic fermenters such as fusobacteria. Here, we show that variable concentrations of free amino acids within pools that represent different dietary protein sources differentially influence fusobacterial growth, including CRC-relevant strains of Fusobacterium spp. This work highlights the high degree of variation in fusobacterial amino acid utilization patterns and suggests differing proportions of dietary amino acids that reach the colon could influence fusobacterial growth.

Short-term alterations in dietary amino acids override host genetic susceptibility and reveal mechanisms of Salmonella Typhimurium small intestine colonization

In addition to individual genetics, environmental factors (e.g., dietary changes) may influence host susceptibility to gastrointestinal infection through unknown mechanisms. Herein, we developed a model in which CBA/J mice, a genetically resistant strain that tolerates intestinal colonization by the enteric pathogen Salmonella Typhimurium (S. Tm), rapidly succumb to infection after exposure to a diet rich in L-amino acids (AA). In mice, S. Tm-gastroenteritis is restricted to the large intestine (cecum), limiting their use to understand S. Tm small intestine (ileum) colonization, a feature of human Salmonellosis. Surprisingly, CBA mice fed AA diet developed ileitis with enhanced S. Tm ileal colonization. Using germ-free mice and ileal-fecal slurry transplant, we found diet-mediated S. Tm ileal expansion to be microbiota-dependent. Mechanistically, S. Tm relied on Fructosyl-asparagine utilization to expand in the ileum during infection. We demonstrate how AA diet overrides host genetics by altering the gut microbiota's ability to prevent S. Tm ileal colonization.

Comparative Analysis of Short-Chain Fatty Acids and the Immune Barrier in Cecum of Dahe Pigs and Dahe Black Pigs

The intestinal immune barrier is a developed and complex immune system, and there is a fine synergy between it and the induced immune response. Short-chain fatty acids (SCFAs) are the main metabolites of intestinal microbial fermentation. In the cecum of pigs, SCFAs not only provide energy for the host but also participate in regulating the function of the intestinal immune system. The purpose of this study was to explore the mechanism of SCFAs in the regulation of immune gene expression in porcine cecum. SCFAs content and mRNA expression levels of immune genes in cecum were detected, and Gene Ontology (GO) function annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, Protein-Protein Interaction Networks (PPI) network construction, key gene identification, and correlation analysis were performed. The results showed that the content of SCFAs in the cecum of Dahe black pigs (DHB) was lower than that of Dahe pigs (DH). There were significant differences in mRNA expression of some immune genes between the two groups. GO functional annotation found terms related to cytokine activity and protein heterodimerization activity; the KEGG pathway was enriched in several pathways related to intestinal immunity. The PPI network identified Interleukin-6 (IL-6), Interleukin-8 (IL-8), Interleukin-10 (IL-10), Interleukin-17A (IL-17A), and Interleukin-18 (IL-18) as key proteins. The correlation analysis showed that acetic acid and valerate were closely related to the immune response. In this study, the differences in cecal short-chain fatty acids and the immune barrier between Dahe pigs and Dahe black pigs were compared, which provided a theoretical basis for improving the intestinal immunity of pigs.

Effect of fecal microbiota transplantation on diabetic wound healing through the IL-17A-mTOR-HIF1α signaling axis

Diabetes is the third most common chronic disorder worldwide. Diabetic wounds are a severe complication that is costly and often results in non-traumatic lower limb amputation. Recent investigations have demonstrated that the gut microbiota as a "virtual organ" can regulate metabolic diseases like diabetes. Fecal microbiota transplantation (FMT) is an innovative therapeutic approach for promoting wound healing, but its function remains incompletely defined. A diabetes model was established by supplying mice with a high-fat diet and performing an intraperitoneal injection of streptozotocin. Diabetic wounds were then created, followed by bacterial transplantation. The relevant indexes of wound healing were evaluated to verify the promoting effect of FMT on the diabetic wounds. Human skin keratinocytes were also cultured, and cell scratch experiments were conducted to further investigate the underlying mechanism. The FMT regulated the levels of specific bacteria in the diabetic mice and helped restore the balance of intestinal microbes. This transplantation also enhanced wound healing in the diabetic mice by augmenting the closure rate, accelerating re-epithelialization, and boosting collagen deposition in skin wounds. Furthermore, FMT promoted the production of IL-17A, which significantly enhanced the growth and movement of human keratinocytes. Inhibiting molecules related to the IL-17A-mTOR-HIF1α signaling axis were shown to hinder wound re-epithelialization.This study clarifies the function of the IL-17A-mTOR-HIF1α signaling axis in the utilization of FMT in diabetic wound healing, providing a new therapeutic method and target for promoting the healing of diabetic wounds.

IMPORTANCE

The Intestinal microbiota, as the organ with the largest number of microorganisms in the body, plays a crucial role in the physiological functions of the human body. Normal microbiota can be involved in various functions such as energy absorption, metabolism, and immunity of the body, and microbiota imbalance is related to many diseases such as obesity and diabetes. Diabetes, as one of the world's three major chronic diseases, is a significant health issue that troubles more than a billion people globally. Diabetic wounds are a problem that all diabetic patients must confront when undergoing surgery, and it is an important cause of non-traumatic amputations. Exploring the role of intestinal microorganisms in the wound-healing process of diabetic mice can offer the possibility of using microorganisms as a therapeutic means to intervene in clinically related diseases.

The Influence of Microorganisms on the Onset and Development of Colorectal Cancer in Humans: A Descriptive Cross-Reference Study

BACKGROUND

The aim of this study is to determine which types of microorganisms influence the onset and development of colorectal cancer (CRC) in humans.

METHODS

In patients with CRC, three swabs were taken for microbiological analysis during surgical removal of the cancer: the first swab from the surface of the healthy intestinal mucosa, the second from the surface of the tumor, and the third from the middle of the tumor tissue.

RESULTS

In the healthy mucosa of the colon, the most prevalent microorganism was Escherichia coli at 70.5%, followed by Enterococcus spp. (47.7%) and Klebsiella/Enterobacter (20.5%). Microbiological analysis of the swabs from the surface of the tumor tissue showed that E. coli was the most prevalent at 72.7%, followed by Enterococcus spp. at 40.9%, Klebsiella/Enterobacter at 25%, and Pseudomonas aeruginosa at 20%. In the center of tumor tissue, E. coli was the most prevalent at 77.3%, followed by Enterococcus spp. at 47.7%, Klebsiella at 27%, and Pseudomonas aeruginosa at 18.2%.

CONCLUSION

Certain types of bacteria can influence the emergence and development of cancer, while other types can suppress the development of tumor tissue. Microbiological analysis of human stool samples can prevent the development of CRC.

Oral microbiota in colorectal cancer: Unraveling mechanisms and application potential

Colorectal cancer (CRC), with a rising prevalence, is the third most commonly diagnosed cancer and the third leading cause of cancer-related death. Studies have shown that a complex interplay between the development of CRC and alterations in the oral microbiome. Recent advancements in genomics and metagenomics have highlighted the significant roles of certain oral microbes, particularly Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum), in the progression of CRC. However, the detailed mechanisms by which the oral microbiota influence CRC development remain unclear. This review aims to elucidate the role of oral microbiota in CRC progression, evaluate their potential as biomarkers, and explore therapeutic strategies targeting these microbes. This review offers insights into the mechanisms underlying the interaction between oral microbiota and CRC, underscoring the potential of oral microbes as diagnostic and prognostic biomarkers, as well as therapeutic targets. Future research should focus on clarifying the exact pathways and developing innovative therapeutic strategies to enhance the diagnosis and treatment.

The probiotic enhances donor microbiota stability and improves the efficacy of fecal microbiota transplantation for treating colitis

INTRODUCTION

The stability and metabolic functionality of donor microbiota are critical determinants of fecal microbiota transplantation (FMT) efficacy in inflammatory bowel disease (IBD). While probiotics show potential to enhance microbiota resilience, their role in optimizing donor microbiota for FMT remains underexplored.

OBJECTIVES

This study investigated whether pretreatment of donor microbiota with L. plantarum GR-4 could improve FMT outcomes in a DSS-induced colitis model by modulating microbial stability, metabolic activity, and host-microbiome interactions.

METHODS

Donor mice received L. plantarum GR-4 for 3 weeks to generate modified FMT (MFMT). DSS-colitis mice were treated with MFMT, conventional FMT, or 5-aminosalicylic acid (5-ASA). Multi-omics analyses and functional assays (stress resistance, engraftment efficiency) were used to evaluate therapeutic mechanisms.

RESULTS

GR-4 pretreatment conferred three key advantages to donor microbiota: Ecological stabilization: 1. GR-4-driven acidification (pH 3.97 vs. 4.59 for LGG, p < 0.0001) enriched butyrogenic Butyricicoccus (73 % butyrate increase, p < 0.05) and improved stress resistance to bile acids/gastric conditions (1.25 × survival vs. FMT). 2. Metabolic reprogramming: GR-4 metabolized 25.3 % of tryptophan (vs. 10.3 % for LGG) to generate immunomodulatory indoles (ILA, IAA), activating aryl hydrocarbon receptor (AHR) signaling and upregulating anti-inflammatory IL-10/IL-22. 3. Bile acid remodeling: MFMT restored sulfolithocholic acid and β-MCA levels, outperforming FMT in resolving DSS-induced dysregulation. MFMT achieved an 83 % remission rate (vs. 50 % for FMT), enhanced gut barrier integrity, and reversed colitis-associated metabolic dysregulation (e.g., elevated spermidine, 7-sulfocholic acid). Probiotic preconditioning improved donor engraftment by 1.25 × and enriched success-associated taxa (Sporobacter, Butyricimonas), while suppressing pathogens (Clostridium papyrosolvens).

CONCLUSIONS

L. plantarum GR-4 optimizes donor microbiota via pH-driven niche engineering, immunometabolic reprogramming, and bile acid modulation, addressing key limitations of conventional FMT. The multi-targeted efficacy of MFMT, evidenced by superior remission rates and metabolic restoration, establishes this approach as a translatable strategy for IBD therapy. This study establishes probiotic-enhanced FMT as a paradigm for precision microbiome interventions.

Tryptophan and Its Metabolite Serotonin Impact Metabolic and Mental Disorders via the Brain-Gut-Microbiome Axis: A Focus on Sex Differences

The crisis of metabolic and mental disorders continues to escalate worldwide. A growing body of research highlights the influence of tryptophan and its metabolites, such as serotonin, beyond their traditional roles in neural signaling. Serotonin acts as a key neurotransmitter within the brain-gut-microbiome axis, a critical bidirectional communication network affecting both metabolism and behavior. Emerging evidence suggests that the gut microbiome regulates brain function and behavior, particularly through microbial influences on tryptophan metabolism and the serotonergic system, both of which are essential for normal functioning. Additionally, sex differences exist in multiple aspects of serotonin-mediated modulation within the brain-gut-microbiome axis, affecting feeding and affective behaviors. This review summarizes the current knowledge from human and animal studies on the influence of tryptophan and its metabolite serotonin on metabolic and behavioral regulation involving the brain and gut microbiome, with a focus on sex differences and the role of sex hormones. We speculate that gut-derived tryptophan and serotonin play essential roles in the pathophysiology that modifies neural circuits, potentially contributing to eating and affective disorders. We propose the gut microbiome as an appealing therapeutic target for metabolic and affective disorders, emphasizing the importance of understanding sex differences in metabolic and behavioral regulation influenced by the brain-gut-microbiome axis. The therapeutic targeting of the gut microbiota and its metabolites may offer a viable strategy for treating serotonin-related disorders, such as eating and affective disorders, with potential differences in treatment efficacy between men and women. This review would promote research on sex differences in metabolic and behavioral regulation impacted by the brain-gut-microbiome axis.

Cardiometabolic benefits of a non-industrialized-type diet are linked to gut microbiome modulation

Industrialization adversely affects the gut microbiome and predisposes individuals to chronic non-communicable diseases. We tested a microbiome restoration strategy comprising a diet that recapitulated key characteristics of non-industrialized dietary patterns (restore diet) and a bacterium rarely found in industrialized microbiomes (Limosilactobacillus reuteri) in a randomized controlled feeding trial in healthy Canadian adults. The restore diet, despite reducing gut microbiome diversity, enhanced the persistence of L. reuteri strain from rural Papua New Guinea (PB-W1) and redressed several microbiome features altered by industrialization. The diet also beneficially altered microbiota-derived plasma metabolites implicated in the etiology of chronic non-communicable diseases. Considerable cardiometabolic benefits were observed independently of L. reuteri administration, several of which could be accurately predicted by baseline and diet-responsive microbiome features. The findings suggest that a dietary intervention targeted toward restoring the gut microbiome can improve host-microbiome interactions that likely underpin chronic pathologies, which can guide dietary recommendations and the development of therapeutic and nutritional strategies.

Molecules-mediated bidirectional interactions between microbes and human cells

Complex molecules-mediated interactions, which are based on the bidirectional information exchange between microbes and human cells, enable the defense against diseases and health maintenance. Recently, diverse single-direction interactions based on active metabolites, immunity factors, and quorum sensing signals have largely been summarized separately. In this review, according to a simplified timeline, we proposed the framework of Molecules-mediated Bidirectional Interactions (MBI) between microbe and humans to decipher and understand their intricate interactions systematically. About the microbe-derived interactions, we summarized various molecules, such as short-chain fatty acids, bile acids, tryptophan catabolites, and quorum sensing molecules, and their corresponding human receptors. Concerning the human-derived interactions, we reviewed the effect of human molecules, including hormones, cytokines, and other circulatory metabolites on microbial characteristics and phenotypes. Finally, we discussed the challenges and trends for developing and deciphering molecule-mediated bidirectional interactions and their potential applications in the guard of human health.

Cecal microbial composition and serum concentration of short-chain fatty acids in laying hens fed different fiber sources

The intestinal microbiota is widely recognized as an integral factor in host health, metabolism, and immunity. In this study, the impact of dietary fiber sources on the intestinal microbiota and the production of short-chain fatty acids (SCFAs) was evaluated in Lohmann White laying hens. The hens were divided into four treatment groups: a control diet without fiber, a diet with wheat bran (mixed fibers), a diet with insoluble fiber (cellulose), and a diet with soluble fiber (pectin), with six replicates of four hens each. Cecal content from 24 hens was analyzed using 16 S rRNA sequencing, while SCFA concentrations were measured in blood serum. Alpha diversity analysis revealed significant variations in microbial richness and diversity among treatments, with higher species richness observed in hens fed wheat bran and cellulose, as indicated by Shannon indices. Principal Coordinates Analysis (PCoA) showed significant differences in microbial composition between the control group and the fiber-supplemented groups. The predominant phyla were Bacteroidetes, Campilobacterota, Firmicutes, and Spirochaetota, with a notable increase in Bacteroidetes in fiber-supplemented groups. Regarding SCFAs, fiber inclusion increased acetic and propionic acid concentrations compared to the control group. Diets with mixed fibers (wheat bran) resulted in the highest acetic acid levels, while propionic acid was most abundant in hens fed soluble fiber (pectin). These findings demonstrate that dietary fiber inclusion to laying hens enhances microbial diversity, stimulates SCFA production, and contributes to host metabolism and health.

Potential of Glycyrrhiza in the prevention of colitis-associated colon cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Glycyrrhiza, a legume native to the Mediterranean region, has a long history of ethnomedicinal use in China. Due to its antiviral, antibacterial, anti-inflammatory, antioxidant, antitumor, anti-ulcer, and hepatoprotective properties, Glycyrrhiza is widely utilized in the treatment of gastrointestinal disorders.

THE AIM OF THE REVIEW

The specific mechanisms of the main active constituents of glycyrrhiza in the treatment of inflammatory bowel disease, precancerous lesions and colorectal cancer at all stages of the colitis-associated colon cancer "Inflammation-Dysplasia-Cancer" sequence, as well as its pharmacokinetics, toxicology, formulation improvements, and application studies, are reviewed to provide new insights and perspectives on glycyrrhiza as a dietary supplement to treat and prevent colitis-associated colon cancer.

MATERIALS AND METHODS

Information on Glycyrrhiza was retrieved from electronic databases, including PubMed and Web of Science.

RESULTS

Glycyrrhiza is a well-established medicinal plant with significant potential for applications in both the food and pharmaceutical industries. Over 400 active constituents have been identified in Glycyrrhiza, including terpenoids, flavonoids, isoflavones, coumarins, and polyphenols. Numerous studies have demonstrated that Glycyrrhiza and its active compounds can inhibit the "Inflammation-Dysplasia-Cancer" progression of colitis-associated colon cancer by mitigating inflammatory bowel disease, reducing the number of intestinal precancerous lesions, and counteracting colorectal cancer. Furthermore, derivatives and nanocarriers are crucial for the effective treatment of colitis-associated colon cancer using Glycyrrhiza and its active constituents.

CONCLUSION

In conclusion, Glycyrrhiza is a plant with both medicinal and nutritional value, making it a potential food ingredient and dietary supplement for the treatment of colitis-associated colon cancer.

Structural characteristics of a heteropolysaccharide from Ganoderma lucidum and its protective effect against Alzheimer's disease via modulating the microbiota-gut-metabolomics

Ganoderma lucidum is a traditional Chinese medicine used to treat Alzheimer's disease (AD), whose main active ingredient is polysaccharides. A heteropolysaccharide named GLPZ-1 was isolated from Ganoderma lucidum. GLPZ-1 (6.608 kDa) predominantly consisted of Glc and minor Gal. The results of GC-MS and NMR analyses indicated that the backbone of GLPZ-1 was mainly composed of 1,4-α-D-Glcp, 1,4,6-α-Glcp and a minor amount of 1,3,4-β-D-Glcp, which was substituted with complex side chains at C-6 of 1,4,6-α-D-Glcp and at C-3 of 1,3,4-β-D-Glcp. GLPZ-1 demonstrated a protective effect on AD rats by improving behavioral abnormalities, alleviating pathological damage and ameliorating levels of IL-6, IL-1β, TNF-α and Th17, which were associated with GLPZ-1 modulating the microbiota-gut-metabolomics of AD rats. GLPZ-1 regulated the gut microbiota in AD rats by increasing the abundance of Bacteroides, unclassified_Lachnospiraceae, Lactobacillus, Pediococcus, Oscillibacter, Lachnoclostridium and Bifidobacterium, while simultaneously reducing the abundance of Pseudomonas and Desulfovibrio. GLPZ-1 could regulate fecal metabolites in AD rats tending towards the normal levels. These regulated fecal metabolites belonged to fatty acid metabolism, cholesterol and bile acid metabolism, neurotransmitters and aromatic amino acid metabolism. These findings provide a preliminary research basis for the exploitation of GLPZ-1 as an effective drug to prevent and delay AD.

Linking microRNA to metabolic reprogramming and gut microbiota in the pathogenesis of colorectal cancer (Review)

Colorectal cancer (CRC), an emerging public health concern, is one of the leading causes of cancer morbidity and mortality worldwide. An increasing body of evidence shows that dysfunction in metabolic reprogramming is a crucial characteristic of CRC progression. Specifically, metabolic reprogramming abnormalities in glucose, glutamine and lipid metabolism provide the tumour with energy and nutrients to support its rapid cell proliferation and survival. More recently, microRNAs (miRNAs) appear to be involved in the pathogenesis of CRC, including regulatory roles in energy metabolism. In addition, it has been revealed that dysbiosis in CRC might play a key role in impairing the host metabolic reprogramming processes, and while the exact interactions remain unclear, the link may lie with miRNAs. Hence, the aims of the current review include first, to delineate the metabolic reprogramming abnormalities in CRC; second, to explain how miRNAs mediate the aberrant regulations of CRC metabolic pathways; third, linking miRNAs with metabolic abnormalities and dysbiosis in CRC and finally, to discuss the roles of miRNAs as potential biomarkers.

Intermittent Fasting: Implications for Obesity-Related Colorectal Tumorigenesis

Obesity is associated with metabolic and immune perturbations (ie, insulin resistance, increased inflammation, and oxidative stress), circadian rhythm dysregulation, and gut microbial changes that can promote colorectal tumorigenesis. Colorectal cancer (CRC) is the third most incident cancer in the United States. This narrative review examines the effects of intermittend fasting on factors influencing colon tumorigenesis, such as body weight, metabolic and immune markers, circadian rythm, and the gut microbiota in humans. Findings suggest that intermittent fasting regimens can lead to weight loss and shifts in metabolic markers, which could be preventive for CRC but effects on the gut microbiota composition and functions still remains elusive.

Roselle Extract Ameliorates Abnormal Glucolipid Metabolism and Gut Microbiota in Obese Mice Fed With High-Fat Diet

Roselle extract (RE) is rich in anthocyanins and chlorogenic acids. This study investigated the health-promoting effects of RE on lipid metabolism, oxidative stress, glycometabolism, and gut microbiota in obese mice fed a high-fat diet (HFD). The obesity model was induced by feeding mice a HFD, with RE supplementation added to their drinking water at concentrations of 2 and 4 mg/mL for 12 weeks. RE significantly reduced body weight gain and fat accumulation compared to the control group, alleviated hepatic steatosis, and improved insulin sensitivity. Additionally, RE restored antioxidative enzyme activities such as SOD and GSH-PX while reducing MDA levels. Transcriptomic analysis of the liver was performed to evaluate gene expression related to lipid metabolism, particularly in the PPAR signaling pathway. Gut microbiota analysis showed that RE increased beneficial bacteria and reduced the Firmicutes-to-Bacteroidetes ratio, suggesting an improvement in gut dysbiosis caused by the HFD. RE enhanced lipid metabolism, reduced oxidative stress, and improved insulin sensitivity in obese mice, potentially through modulation of the PPAR signaling pathway and gut microbiota, suggesting its potential as a therapeutic candidate for obesity-related metabolic disorders.

Roux-en-Y gastric bypass-associated fecal tyramine promotes colon cancer risk via increased DNA damage, cell proliferation, and inflammation

BACKGROUND

Fecal abundances of Enterobacteriaceae and Enterococcaceae are elevated in patients following Roux-en-Y gastric bypass (RYGB) surgery. Concurrently, fecal concentrations of tyramine, derived from gut bacterial metabolism of tyrosine and/or food, increased post-RYGB. Furthermore, emerging evidence suggests that RYGB is associated with increased colorectal cancer (CRC) risk. However, the causal link between RYGB-associated microbial metabolites and CRC risk remains unclear. Hence, this study investigated the tyrosine metabolism of Enterobacteriaceae and Enterococcaceae strains isolated from patients post-RYGB and explored the causal effects of tyramine on the CRC risk and tumorigenesis using both human colonic cancer cell line (HCT 116) and wild-type and ApcMin/+ mice.

RESULTS

We isolated 31 bacterial isolates belonging to Enterobacteriaceae and Enterococcaceae families from the feces of patients with RYGB surgery. By culturing the isolates in tyrosine-supplemented medium, we found that Citrobacter produced phenol as a main product of tyrosine, whereas Enterobacter and Klebsiella produced 4-hydroxyphenylacetate, Escherichia produced 4-hydroxyphenyllactate and 4-hydroxyphenylpyruvate, and Enterococcus and two Klebsiella isolates produced tyramine. These observations suggested the gut bacterial contribution to increased fecal concentrations of tyramine post-RYGB. We subsequently evaluated the impact of tyramine on CRC risk and development. Tyramine induced necrosis and promoted cell proliferation and DNA damage of HCT 116 cells. Daily oral administration of tyramine for 49 days to wild-type mice resulted in visible adenomas in 5 out of 12 mice, accompanied by significantly enhanced DNA damage (γH2AX +) and an increased trend of cell proliferation (Ki67 +) in the ileum, along with an upregulated expression of the cell division cycle gene (Cdc34b) in the colon. To evaluate the impact of tyramine on intestinal tumor growth, we treated ApcMin/+ mice with the same doses of tyramine and duration. These mice showed larger colonic tumor size and increased intestinal cell proliferation and inflammation (e.g., increased mRNA expression of IL-17A and higher number of Ly6G + neutrophils) compared to water-treated ApcMin/+ control mice.

CONCLUSIONS

Our results collectively suggested that RYGB-associated fecal bacteria could contribute to tyramine production and tyramine increased CRC risk by increasing DNA damage, cell proliferation, and pro-inflammatory responses of the gut. Monitoring and modulating tyramine concentrations in high-risk individuals could aid CRC prognosis and management. Video Abstract.

Gut microbial-derived N-acetylmuramic acid alleviates colorectal cancer via the AKT1 pathway

BACKGROUND

Gut microbial metabolites are recognised as critical effector molecules that influence the development of colorectal cancer (CRC). Peptidoglycan fragments (PGFs) produced by microbiota play a crucial role in maintaining intestinal homeostasis, but their role in CRC remains unclear.

OBJECTIVE

Here, we aimed to explore the potential contribution of PGFs in intestinal tumourigenesis.

DESIGN

The relative abundance of peptidoglycan synthase and hydrolase genes was assessed by metagenomic analysis. Specific PGFs in the faeces and serum of CRC patients were quantified using targeted mass spectrometry. The effects of PGF on intestinal tumourigenesis were systematically evaluated using various murine models of CRC and organoids derived from CRC patients. Downstream molecular targets were screened and evaluated using proteome microarray, transcriptome sequencing and rescue assays.

RESULTS

Metagenomic analysis across seven independent cohorts (n=1121) revealed a comprehensive reduction in peptidoglycan synthase gene relative abundance in CRC patients. Targeted mass spectrometry identified significant depletion of a specific PGF, N-acetylmuramic acid (NAM) in CRC patients, which decreased as tumours progressed (p<0.001). NAM significantly inhibits intestinal tumourigenesis in various models, including Apc Min/+, AOM/DSS-treated and MC38 tumour-bearing mice. Additionally, NAM inhibits the growth of patient-derived CRC organoids in a concentration-dependent manner. Mechanistically, NAM inhibits the activation of AKT1 by directly binding to it and blocking its phosphorylation, which is a partial mediator of NAM's anticancer effects.

CONCLUSION

The PGF NAM protects against intestinal tumourigenesis by targeting the AKT1 signalling pathway. NAM may serve as a novel potential preventive and therapeutic biomarker against CRC.

Serum metabolic characteristics associated with the deterioration of colorectal adenomas

Colorectal cancer (CRC) can evolve from colorectal adenomas, which can be further classified into non-advanced adenomas (NAAs) and advanced adenomas (AAs) based on their clinical characteristics. Their prognoses are vastly different, with patients with NAAs having significantly lower recurrence and CRC-related mortality rates than those with AA or CRC. Although serum metabolomics has shown promise for the early diagnosis of CRC, the differences in serum metabolite composition between NAA and AA still need to be further elucidated. This study aimed to explore the mechanism of CRC occurrence and development based on the unique serum metabolic fingerprints of different stages of CRC and to discover a new non-invasive diagnostic method based on serum metabolomics. A clinical CRC progression cohort containing healthy control (NC; n = 40), NAA (n = 40), AA (n = 40), and CRC (n = 22) groups was constructed, and untargeted metabolomic analysis based on liquid chromatography/mass spectrometry was performed to analyze the serum metabolite characteristics of each group. A semi-quantitative analysis of intergroup metabolite differences was conducted, focusing on specific metabolites that differed in the NAA and AA groups. Finally, variable metabolites were selected based on least absolute shrinkage and selection operator (LASSO) regression analysis, and receiver operating characteristic curves were plotted to evaluate the efficacy of the serum metabolite-based diagnostic model in distinguishing NC/NAA populations from AA/CRC populations. Metabolomic analysis revealed significant differences in the composition of metabolites in the NC and NAA groups compared to the CRC group, whereas the serum metabolites of the AA group were similar to those of the CRC group. The levels of 33 metabolites were significantly different in the serum of AA/CRC patients compared to that of NAA patients, and their functions included glycerophospholipid, sphingolipid, and caffeine metabolism. LASSO regression analysis identified 57 differential metabolite variables between the NC/NAA and AA/CRC groups. The diagnostic model constructed using the random forest algorithm had the best discrimination effect, with areas under the curve of 1.000 (95% confidence interval [CI] 1.000-1.000) and 0.685 (95% CI 0.540-0.830) for the training and testing sets, respectively. The composition of serum metabolites is specific to the different stages of CRC development. The serum metabolite composition of patients with AAs was similar to that of patients with CRC. Auxiliary diagnostic measures based on serum metabolites have the potential to guide the follow-up and treatment of patients with adenoma.

The Effects of Prebiotic Supplementation on Markers of Exercise-Induced Gastrointestinal Syndrome in Response to Exertional Heat Stress

Exercise perturbs various aspects of gastrointestinal integrity and function, which may lead to performance impeding gastrointestinal symptoms (GIS) and/or precipitate clinical issues warranting medical management. This study aimed to determine the impact of prebiotic supplementation on gastrointestinal integrity and functional status in response to exertional heat stress (EHS). Sixteen endurance athletes completed two trials of 3-hr running at 60% V˙O2max in 30 °C at baseline (T1) and following an 8-week supplementation period (T2), with 16 g/day prebiotic (PREBIOTIC) or matched placebo (PLACEBO). Blood samples were collected pre-EHS and post-EHS and in recovery for determination of stress response (cortisol), intestinal epithelial injury (intestinal fatty acid binding protein), bacterial endotoxemia (sCD14), and systemic inflammation (C-reactive protein). GIS and feeding tolerance variables were assessed throughout the EHS. Orocecal transit time was determined via a lactulose challenge given at 2.5 hr into EHS. Plasma cortisol (combined mean: +252 ng/ml), intestinal fatty acid binding protein (+800 pg/ml), and sCD14 (+487 ng/ml) concentrations increased in response to EHS in T1 (p ≤ .05), but not for C-reactive protein (+0.8 μg/ml; p > .05), in both PREBIOTIC and PLACEBO. PREBIOTIC supplementation resulted in a blunted intestinal fatty acid binding protein response on T2 (+316 pg/ml) compared with an increase (+1,001 ng/ml) in PLACEBO (p = .005). Lower sCD14 was observed at T2 (2,799 ng/ml) versus T1 (3,246 ng/ml) in PREBIOTIC only (p = .039). No intervention effects were observed for C-reactive protein. No difference within or between PREBIOTIC and PLACEBO at T1 and T2 was observed for orocecal transit time, GIS, and feeding tolerance. In conclusion, 8 weeks of prebiotic supplementation modestly attenuates EHS associated perturbations to intestinal integrity, but does not further impair gastrointestinal transit and/or exacerbate EHS associated GIS or feeding tolerance.

Causal relationship between gut microbiota and dental caries: A Mendelian randomization analysis

The onset of dental caries is associated with multiple factors, including oral microbiota, dietary sugars, the defensive mechanisms of saliva and teeth, oral hygiene practices, and socioeconomic factors. However, its relationship with the gut microbiota remains to be further explored. It remains crucial to establish a definitive causal link between the gut microbiota and the development of dental caries. This study aimed to investigate the causal relationship between gut microbiota and the risk of dental caries, focusing on identifying specific microbial communities potentially implicated in its pathogenesis. Gut microbiota data from genome-wide association studies (GWAS) conducted by the MiBioGen consortium were utilized as the exposure variable, with dental caries as the outcome variable. A Mendelian randomization (MR) approach was employed, leveraging comprehensive, publicly available GWAS summary data from European populations. The primary analytical method was the inverse variance weighted method, supplemented by additional techniques such as the weighted median model, MR-Egger, simple mode, and weighted mode, to ensure the robustness of the results. Heterogeneity was evaluated using Cochran Q test, and potential pleiotropy was assessed through MR-Egger regression. Sensitivity analyses were performed using the leave-one-out method to further validate the findings. The results revealed that a higher relative abundance of Christensenellaceae, FamilyXIII, Ruminococcaceae, and Senegalimassilia was associated with a reduced risk of dental caries. In contrast, a higher relative abundance of Erysipelotrichia, Erysipelotrichales, Pasteurellales, Erysipelotrichaceae, Pasteurellaceae, Methanobrevibacter, Roseburia, and Terrisporobacter was linked to an elevated risk of dental caries. This study provides compelling evidence for a causal relationship between gut microbiota and the development of dental caries, offering novel insights into the potential role of specific gut microbial communities in the pathogenesis of dental caries.

Isomaltodextrin inhibits kidney enlargement induced by a high-protein diet through its metabolism by gut microbiota

To evaluate the effects of the soluble fiber isomaltodextrin in a protein-biased diet, a 21-day protein diet trial was conducted in rats, with 60% of the calories derived from protein. The results revealed that the high-protein diet alone led to a significant increase in kidney weight. In contrast, the consumption of water with 5% isomaltodextrin dissolved in it, along with a high-protein diet, suppressed this weight gain. To elucidate this mechanism, an analysis of serum urea toxins confirmed that the concentrations of phenyl sulfate were significantly higher with high protein, and significantly lower with isomaltodextrin. The impact of a high-protein diet increased phenol in cecal contents, an increase that was mitigated by isomaltodextrin. This suggests that the inhibitory effect of isomaltodextrin on renal hypertrophy was due to the suppression of urea toxin precursor production by the gut microbiota.

Microbiota and Radiotherapy: Unlocking the Potential for Improved Gastrointestinal Cancer Treatment

Radiotherapy (RT) is one of the major cornerstones in managing gastrointestinal (GI) cancers. However, several side effects, such as intestinal inflammation, mucosal injury, and dysbiosis, often compromise this. The gut microbiota increasingly attracts much interest as an essential modulator of RT effects influencing immune responses and tissue repair. Through short-chain fatty acids such as butyrate, representatives of certain bacterial species play a crucial role under normal conditions, keeping the mucosal integrity intact and reducing oxidative stress-mediated damage. Dysbiosis, a state where diminished microbial diversity and increased pathogenic species in the microbiota are seen, amplifies RT-induced toxicity in patients. Clinical investigations highlight that microbiota-targeted interventions, including probiotics, prebiotics, and fecal microbiota transplantation, hold the means to augment RT efficacy and lessen toxicity. Increased microflora diversity and specific microbial profiles have yielded serious patient improvements. Advanced RT methods use stereotactic body radiotherapy combined with microbiota modulation as a promising technique to shield healthy tissue and maximize immune-mediated antitumor effects. Additionally, there is an implication in tumor behavior regulated by the intratumoral microbiota regarding the response to radiotherapy. Notably, the modulation of gut and tumor microbiota provides an avenue to optimize RT benefits in GI cancers, underscoring the importance of personalized therapy.

Rurality and relative poverty drive acquisition of a stable and diverse gut microbiome in early childhood in a non-industrialized setting

There are limited longitudinal data from non-industrialized settings on patterns and determinants of gut bacterial microbiota development in early childhood. We analysed epidemiological data and stool samples collected from 60 children followed from early infancy to 5 years of age in a rural tropical district in coastal Ecuador. Data were collected longitudinally on a wide variety of individual, maternal, and household exposures. Extracted DNA from stool samples were analysed for bacterial microbiota using 16S rRNA gene sequencing. Both alpha and beta diversity indices suggested stable profiles towards 5 years of age. Greater alpha diversity and lower beta diversity were associated with factors typical of rural poverty including low household incomes, overcrowding, and greater agricultural and animal exposures. Consumption of unpasteurized milk was consistently associated with greater alpha diversity indices. Delivery method and antibiotic exposures during pregnancy and early childhood appeared to have limited effects on developmental trajectories of gut microbiota. Infants living in a non-industrialized setting in conditions of greater poverty and typically rural exposures appeared to acquire more rapidly a stable and diverse gut bacterial microbiome during childhood.

Advances in Engineered Phages for Disease Treatment

Phage therapy presents a promising solution for combating multidrug-resistant (MDR) bacterial infections and other bacteria-related diseases, attributed to their innate ability to target and lyse bacteria. Recent clinical successes, particularly in treating MDR-related respiratory and post-surgical infections, validated the therapeutic potential of phage therapy. However, the complex microenvironment within the human body poses significant challenges to phage activity and efficacy in vivo. To overcome these barriers, recent advances in phage engineering have aimed to enhance targeting accuracy, improve stability and survivability, and explore synergistic combinations with other therapeutic modalities. This review provides a comprehensive overview of phage therapy, emphasizing the application of engineered phages in antibacterial therapy, tumor therapy, and vaccine development. Furthermore, the review highlights the current challenges and future trends for advancing phage therapy toward broader clinical applications.

Fecal Short-Chain Fatty Acids Are Associated with Obesity in Gestational Diabetes

Background: Short-chain fatty acids (SCFAs), which are produced by the microbial fermentation of undigested carbohydrates, play an important role in the metabolism and physiology of the host. SCFAs are involved in the regulation of maternal metabolism during pregnancy and influence weight gain, glucose metabolism, and metabolic hormones. Methods: In 2017, women who were treated for gestational diabetes mellitus (GDM) at the University Medical Centre Ljubljana were invited to participate in a longitudinal study. A total of 45 women were included in this study and comprehensively phenotyped. During the second and third trimester of pregnancy, the women with GDM provided fecal samples for SCFA analysis. The samples were analyzed by high-performance liquid chromatography for the simultaneous determination of acetate, propionate, and butyrate. Results: SCFA concentrations in feces differed between overweight/obese and normal-weight women with GDM. Acetate and propionate concentrations were significantly higher in pregnant women who were overweight or obese before pregnancy compared to normal-weight women but butyrate concentrations were not. Butyrate was elevated in the third trimester in the group with excessive gestational weight gain. Conclusions: The relationship between SCFAs and obesity is complex, and the association between SCFAs and GDM remains to be clarified. Regardless of the conflicting publications on the role of SCFAs, our study showed that higher acetate and propionate levels were associated with the weight categories of overweight or obesity before pregnancy and higher butyrate levels were associated with excessive gestational weight gain.

The relationship between pathogenic bacteria and different stages of colorectal cancer

Colorectal cancer (CRC) involves uncontrolled cell growth in the colon and rectum. This study aims to explore the prevalence of key pathogenic bacteria and their role in the progression of CRC, focusing on microbial dysbiosis. This study analyzed 52 stool and tissue samples through polymerase chain reaction (PCR), real-time PCR, and bioinformatics to identify associations between pathogenic bacteria and CRC progression. PCR results revealed a significant association between the Bacteroides fragilis toxin (bft) gene and CRC progression (P = 0.001, r = 0.570). Furthermore, Real-time PCR showed significant differences in the frequency of pks+Escherichia coli in CRC stages 1 (P = 0.03), 2 (P = 0.004), and 3 (P = 0.0002) compared to the control group. Additionally, the frequency of Fusobacterium nucleatum in stage 3 CRC patients was significantly higher than in the control group (P = 0.004) and stage 1 patients (P = 0.01). Furthermore, Streptococcus gallolyticus showed similar significant differences in stage 3 patients (P = 0.004). Bioinformatics analyses using KEGG, Reactome, STRING, and dbSNP highlighted bacteria's roles in colorectal carcinogenesis, emphasizing the need for early identification and management in CRC treatment and prevention strategies. Finally, due to the limitations of the study, the use of more advanced methods and the validation of results through more reliable techniques are essential for future research.

Exploring the gut microbiome: A potential biomarker for cancer diagnosis, prognosis, and therapy

The gut microbiome, a complex community of trillions of microorganisms in the intestines, is crucial in maintaining human health. Recent advancements in microbiome research have unveiled a compelling link between the gut microbiome and cancer development and progression. Alterations in the composition and function of the gut microbiome, known as dysbiosis, have been implicated in various types of cancer, including, esophageal, liver, colon, pancreatic, and gastrointestinal. However, the specific gut microbial strains associated with the development or progression of cancers in various tissues remain largely unclear. Here, we summarize current research findings on the gut microbiome of multiple cancers. This review aims to identify key gut microbial targets that closely influence cancer development based on current research findings. To accurately evaluate the effectiveness of the gut microbiome as a clinical tool for cancer, further research is needed to explore its potential as a biomarker and therapeutic strategy.

Conjugated linoleic acid metabolite impact in colorectal cancer: a potential microbiome-based precision nutrition approach

Colorectal cancer (CRC) is the second most deadly and the third most diagnosed cancer in both sexes worldwide. CRC pathogenesis is associated with risk factors such as genetics, alcohol, smoking, sedentariness, obesity, unbalanced diets, and gut microbiota dysbiosis. The gut microbiota is the microbial community living in symbiosis in the intestine, in a dynamic balance vital for health. Increasing evidence underscores the influence of specific gut microbiota bacterial species on CRC incidence and pathogenesis. In this regard, conjugated linoleic acid (CLA) metabolites produced by certain gut microbiota have demonstrated an anticarcinogenic effect in CRC, influencing pathways for inflammation, proliferation, and apoptosis. CLA production occurs naturally in the rumen, and human bioavailability is through the consumption of food derived from ruminants. In recent years, biotechnological attempts to increase CLA bioavailability in humans have been unfruitful. Therefore, the conversion of essential dietary linoleic acid to CLA metabolite by specific intestinal bacteria has become a promising process. This article reviews the evidence regarding CLA and CLA-producing bacteria as therapeutic agents against CRC and investigates the best strategy for increasing the yield and bioavailability of CLA. Given the potential and limitations of the present strategies, a new microbiome-based precision nutrition approach based on endogenous CLA production by human gut bacteria is proposed. A literature search in the PubMed and PubMed Central databases identified 794 papers on human gut bacteria associated with CLA production. Of these, 51 studies exploring association consistency were selected. After excluding 19 papers, due to health concerns or discrepancies between studies, 32 papers were selected for analysis, encompassing data for 38 CLA-producing bacteria, such as Bifidobacterium and Lactobacillus species. The information was analyzed by a bioinformatics food recommendation system patented by our research group, Phymofood (EP22382095). This paper presents a new microbiome-based precision nutrition approach targeting CLA-producing gut bacterial species to maximize the anticarcinogenic effect of CLA in CRC.