Saturated long-chain fatty acid-producing bacteria contribute to enhanced colonic motility in rats

A Diet Fortified with Anthocyanin-Rich Extract (RED) Reduces Ileal Inflammation in a Senescence-Prone Mice Model of Crohn's-Disease-like Ileitis

SAMP mice develop progressive Crohn's disease (CD)-like ileitis without spontaneous colitis that worsens over time without chemical, genetic, or immunological manipulation. Even growing in an identical vivarium and fed with the same diet, SAMP mice reveal a distinct fecal microbiome, metabolome, and lipidome profile compared to AKR mice, their non-inflamed parental control strain. Differences are already present in 5-week-old mice, with a tendency to increase in 15-week-old mice. SAMP and AKR mice metabolome and lipidome profiles were substantially different, belonging to two clusters in line with the progression of intestinal disease. Similarly, the 16S analysis confirmed differences between 15-week-old AKR and SAMP mice. The protective role of dietary polyphenols has been documented in inflammatory bowel diseases (IBD); thus, we supplemented the chow diet with an anthocyanin-rich extract (RED) to evaluate disease reduction in SAMP mice and changes in fecal microbiota/metabolome. Our data reveal that 10-week supplementation with anthocyanin-rich extract ameliorated disease severity in SAMP mice despite limited fecal microbiota/metabolome differences.

Neutrophil Depletion Reduced the Relative Abundance of Unsaturated Long-Chain Fatty Acid Synthesis Microbiota and Intestinal Lipid Absorption

As immune cells, neutrophils serve as the first line of defense against infections; however, the mechanism by which neutrophils regulate lipid metabolism is unknown. The neutrophil depletion group was treated with 100 μg InVivoMAb anti-mouse Ly6G 6 times, whereas the control group mice were intraperitoneally injected with the same quantity of InVivoMAb rat IgG2a. Body fat content, triglycerides (TGs), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) in the jejunum and ileum, as well as 9 long-chain fatty acids (LCFAs) in the intestinal contents were significantly decreased. Furthermore, genes involved in the absorption of lipids in each segment of the intestine also showed decreased expression. Neutrophil-depletion and control models were administered 25 μCi of 3H-cholesterol by gavage. The distribution of 3H cholesterol in the intestinal segment, heart, liver, serum, and feces was not altered by anti-Ly6G antibodies. Metagenomics was applied to investigate uncultured microorganisms in the intestinal contents to identify bacteria containing lipid metabolism genes. At the species level, 12 bacteria were involved in unsaturated LCFA synthesis, among which 2 increased and 10 decreased. The overall relative abundance of these bacteria decreased from 3.102% to 0.734%. Many genes involved in lipid metabolism were also reduced as a result, such as fatty acid synthase and peroxisome proliferator-activated receptor γ. In conclusion, neutrophil depletion does not affect intestinal lipid absorption in the diet but leads to a decrease in the overall relative abundance of gut bacteria involved in unsaturated LCFA synthesis. Consequently, intestinal lipid synthesis and absorption are reduced.

Advances in Fecal Microbiota Transplantation for Gut Dysbiosis-Related Diseases

This article provides an overview of the advancements in the application of fecal microbiota transplantation (FMT) in treating diseases related to intestinal dysbiosis. FMT involves the transfer of healthy donor fecal microbiota into the patient's body, aiming to restore the balance of intestinal microbiota and thereby treat a variety of intestinal diseases such as recurrent Clostridioides difficile infection (rCDI), inflammatory bowel disease (IBD), constipation, short bowel syndrome (SBS), and irritable bowel syndrome (IBS). While FMT has shown high efficacy in the treatment of rCDI, further research is needed for its application in other chronic conditions. This article elaborates on the application of FMT in intestinal diseases and the mechanisms of intestinal dysbiosis, as well as discusses key factors influencing the effectiveness of FMT, including donor selection, recipient characteristics, treatment protocols, and methods for assessing microbiota. Additionally, it emphasizes the key to successful FMT. Future research should focus on optimizing the FMT process to ensure long-term safety and explore the potential application of FMT in a broader range of medical conditions.

The Particle Size of Wheat Bran Dietary Fiber Influences Its Improvement Effects on Constipation

Wheat bran dietary fiber (WBDF) is a potential functional additive to enrich products used for relieving constipation. The purpose of this study was to understand the effects of different particle size ranges (mean sizes of 84.14, 61.74, 37.39, and 22.33 μm) of WBDF on constipation. With the decrease in particle size, its morphology exhibited an increase in fiber fragmentation, larger pore sizes, and the formation of structural faults. The oil-holding capacity (OHC) and swelling capacity (SC) of WBDF were found to change with particle size, with the highest OHC observed at 37.39 μm and the greatest SC at 84.14 μm. Animal experiments demonstrated that the WBDF of smaller particle sizes significantly alleviated loperamide-induced constipation with an increased intestinal propulsion rate, decreased first melanin excretion time, and reduced gastric residual rate. Meanwhile, WBDF samples markedly increased serum MTL and serum AChE levels. Notably, compared with the constipation model (CMNC) group, the small intestinal propulsion rate in the MPS40 group increased by 41.21%, and the gastric residue rate significantly decreased by 19.69%. The improvement in constipation symptoms was most pronounced. Additionally, the abundance of Lactobacillus in the MPS40 group increased by 52.52%, while the relative abundance of Prevotella decreased by 83.55%, and the diversity of the gut microbiota was altered. These findings provide valuable insights into the potential commercial applications of WBDF in fiber-enriched functional foods to support intestinal health.

Recent genetic drift in the co-diversified gut bacterial symbionts of laboratory mice

Laboratory mice (Mus musculus domesticus) harbor gut bacterial strains that are distinct from those of wild mice but whose evolutionary histories are unclear. Here, we show that laboratory mice have retained gut bacterial lineages that diversified in parallel (co-diversified) with rodent species for > 25 million years, but that laboratory-mouse gut microbiota (LGM) strains of these ancestral symbionts have experienced accelerated accumulation of genetic load during the past ~ 120 years of captivity. Compared to closely related wild-mouse gut microbiota (WGM) strains, co-diversified LGM strains displayed significantly faster genome-wide rates of nonsynonymous substitutions, indicating elevated genetic drift-a difference that was absent in non-co-diversified symbiont clades. Competition experiments in germ-free mice further indicated that LGM strains within co-diversified clades displayed significantly reduced fitness in vivo compared to WGM relatives to an extent not observed within non-co-diversified clades. Thus, stochastic processes (e.g., bottlenecks), not natural selection in the laboratory, have been the predominant evolutionary forces underlying divergence of co-diversified symbiont strains between laboratory and wild house mice. Our results show that gut bacterial lineages conserved in diverse rodent species have acquired novel mutational burdens in laboratory mice, providing an evolutionary rationale for restoring laboratory mice with wild gut bacterial strain diversity.

FECAL CALPROTECTIN AND INTESTINAL METABOLITES: WHAT IS THEIR IMPORTANCE IN THE ACTIVITY AND DIFFERENTIATION OF PATIENTS WITH INFLAMMATORY BOWEL DISEASES?

BACKGROUND

Inflammatory bowel disease (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC), lacks a known etiology. Although clinical symptoms, imaging, and colonoscopy are common diagnostic tools, fecal calprotectin (FC) serves as a widely used biomarker to track disease activity. Metabolomics, within the omics sciences, holds promise for identifying disease progression biomarkers. This approach involves studying metabolites in biological media to uncover pathological factors.

AIMS

The purpose of this study was to explore fecal metabolomics in IBD patients, evaluate its potential in differentiating subtypes, and assess disease activity using FC.

METHODS

Cross-sectional study including IBD patients, clinical data, and FC measurements (=200 μg/g as an indicator of active disease).

RESULTS

Fecal metabolomics utilized chromatography mass spectrometry/solid phase microextraction with MetaboAnalyst 5.0 software for analysis. Of 52 patients (29 UC, 23 CD), 36 (69.2%) exhibited inflammatory activity. We identified 56 fecal metabolites, with hexadecanoic acid, squalene, and octadecanoic acid notably distinguishing CD from UC. For UC, octadecanoic and hexadecanoic acids correlated with disease activity, whereas octadecanoic acid was most relevant in CD.

CONCLUSIONS

These findings highlight the potential of metabolomics as a noninvasive complement for evaluating IBD, aiding diagnosis, and assessing disease activity.

All roads lead to Rome: the plasticity of gut microbiome drives the extensive adaptation of the Yarkand toad-headed agama (Phrynocephalus axillaris) to different altitudes

The gut microbiome was involved in a variety of physiological processes and played a key role in host environmental adaptation. However, the mechanisms of their response to altitudinal environmental changes remain unclear. In this study, we used 16S rRNA sequencing and LC-MS metabolomics to investigate the changes in the gut microbiome and metabolism of the Yarkand toad-headed agama (Phrynocephalus axillaris) at different altitudes (-80 m to 2000 m). The results demonstrated that Firmicutes, Bacteroidetes, and Proteobacteria were the dominant phylum, Lachnospiraceae and Oscillospiraceae were the most abundant family, and the low-altitude populations had higher richness than high-altitude populations; Akkermansiaceae appeared to be enriched in high-altitude populations and the relative abundance tended to increase with altitude. The gut microbiome of three populations of P. axillaris at different altitudes was clustered into two different enterotypes, low-altitude populations and high-altitude populations shared an enterotype dominated by Akkermansia, Kineothrix, Phocaeicola; intermediate-altitude populations had an enterotype dominated by Mesorhizobium, Bradyrhizobium. Metabolites involved in amino acid and lipid metabolism differed significantly at different altitudes. The above results suggest that gut microbiome plasticity drives the extensive adaptation of P. axillaris to multi-stress caused by different altitudes. With global warming, recognizing the adaptive capacity of wide-ranging species to altitude can help plan future conservation strategies.

Oral administration of pioglitazone inhibits pulmonary hypertension by regulating the gut microbiome and plasma metabolome in male rats

The oral administrated thiazolidinediones (TZDs) have been widely reported to alleviate experimental pulmonary hypertension (PH). However, previous studies mainly focused on their beneficial effects on the cardiopulmonary vascular system but failed to determine their potential roles on gut microenvironment. This study aims to investigate the effects of pioglitazone, an oral TZD drug, on gut microbiome in classic PH rat models induced by hypoxia (HPH) or SU5416/hypoxia (SuHx-PH) and evaluate the therapeutic potential of supplementation of selective probiotics for experimental PH. Pioglitazone remarkably inhibited the PH pathogenesis in both models and reshaped the gut microbiome and plasma metabolome. Correlation analyses represented strong and unique association between the protective metabolites and bacteria genera (Roseburia, Lactobacillus, and Streptococcus) that were positively stimulated by pioglitazone. Supplementation of selective probiotics Roseburia intestinalis (R. intestinalis) partially attenuated SuHx-PH and rebuilt a novel gut microbiome and host metabolome. This study reports for the first time that oral administration of pioglitazone protects PH by regulating the gut microbiome and host metabolome, providing novel insights for the TZD drugs. The data also supports that modulation of gut microbiota by supplementation of selective probiotics could be a novel effective therapeutic strategy for the treatment of PH.

Protective Effects of Spondias mombin L. Juice Alone or in Combination With Lactobacillus acidophilus in 5-Fluorouracil-Induced Experimental Intestinal Mucositis

BACKGROUND

Evaluate the impact of Spondias mombin L. juice (SM), alone and in combination with Lactobacillus acidophilus, in an experimental model of intestinal mucositis.

METHODS

Swiss mice were orally administered with saline, SM, or SM combined with L. acidophilus NRRL B-4495 at 1 × 109 colony-forming unit (CFU/mL) for 15 days before the induction of intestinal mucositis by a single intraperitoneal injection of 5-fluorouracil (5-FU) at 450 mg/kg. On the 18th day, following euthanasia, tissue samples were collected for histopathological examination. Jejunum tissues were analyzed for MUC-2 immunoexpression, concentrations of interleukin-1-beta (IL-1β), interleukin 6 (IL-6) and tumor necrosis factor (TNF)-α, and invertase activity.

KEY RESULTS

5-FU induced intestinal damage in all intestinal segments, and this damage involved villus blunting, flattened and vacuolated cells, crypt necrosis, inflammatory cell infiltration, and mucosa and submucosal edema compared to the control group. In contrast, SM or SM with L. acidophilus prevented these morphological alterations in all intestinal segments (p < 0.05). Both treatments reduced the intestinal concentration of IL-1 beta (p < 0.05), IL-6 (p < 0.05), and TNF-alpha (p < 0.05). Notably, the combination of SM and L. acidophilus, but not SM alone, prevented the 5-FU-induced decrease in invertase activity and mucin expression (p < 0.05). Furthermore, SM combined with L. acidophilus resulted in an increased population of lactic acid bacteria in feces on the 7th and 18th days. Combining SM with L. acidophilus also decreased fecal excretion of γ-Ergostenol and γ-sitosterol.

CONCLUSIONS AND INFERENCES

SM, alone and combined with Lactobacillus acidophilus demonstrated significant protective effects against 5-FU-induced intestinal mucositis, reducing inflammatory markers.

Chronic constipation and gut microbiota: current research insights and therapeutic implications

Chronic constipation is a prevalent clinical condition. Its etiology and pathogenesis have not yet been fully understood. In recent years, mounting evidence suggests a close association between chronic constipation and intestinal dysbiosis, including alterations in the colony structure and metabolites, as well as the modulation of bowel movements via the brain-gut-microbiota axis. With the deepening of related research, probiotic-related therapies are expected to become a potential first-line treatment for chronic constipation in the future. In this review, we summarize the current research insights into the intricate relationships between chronic constipation and the gut microbiota and briefly discuss several different approaches for treating chronic constipation. The findings from this review may advance our understanding of the pathological mechanisms underlying chronic constipation and, ultimately, translate them into improvements in patient care.

Dysbiosis index and fecal concentrations of sterols, long-chain fatty acids and unconjugated bile acids in dogs with inflammatory protein-losing enteropathy

Introduction

Canine protein-losing enteropathy (PLE) is a syndrome characterized by gastrointestinal loss of proteins. While fecal microbiome and metabolome perturbations have been reported in dogs with chronic enteropathy, they have not been widely studied in dogs with PLE. Therefore, the study aims were to investigate gut microbiome and targeted fecal metabolites in dogs with inflammatory PLE (iPLE) and evaluate whether treatment affects these changes at short-term follow-up.

Methods

Thirty-eight dogs with PLE and histopathological evidence of gastrointestinal inflammation and 47 healthy dogs were enrolled. Fecal samples were collected before endoscopy (T0) and after one month of therapy (T1). Microbiome and metabolome alterations were investigated using qPCR assays (dysbiosis index, DI) and gas chromatography/mass spectrometry (long-chain fatty acids, sterols, unconjugated bile acids), respectively.

Results

Median (min-max) DI of iPLE dogs was 0.4 (-5.9 to 7.7) and was significantly higher (p < 0.0001) than median DI in healthy dogs [-2.0 (-6.0 to 5.3)]. No significant associations were found between DI and selected clinicopathological variables. DI did not significantly differ between T0 and T1. In iPLE dogs, at T0, myristic, palmitic, linoleic, oleic, cis-vaccenic, stearic, arachidonic, gondoic, docosanoic, erucic, and nervonic acids were significantly higher (p < 0.0001) than healthy dogs. In iPLE dogs, oleic acid (p = 0.044), stearic acid (p = 0.013), erucic acid (p = 0.018) and nervonic acid (p = 0.002) were significantly decreased at T1. At T0, cholesterol and lathosterol (p < 0.0001) were significantly higher in iPLE dogs compared to healthy dogs, while total measured phytosterols were significantly lower (p = 0.001). No significant differences in total sterols, total phytosterols and total zoosterols content were found at T1, compared to T0. At T0, total primary bile acids and total secondary bile acids did not significantly differ between healthy control dogs and iPLE dogs. No significant differences in fecal bile acid content were found at T1.

Discussion

Dysbiosis and lipid metabolism perturbations were observed in dogs with iPLE. Different therapeutic protocols lead to an improvement of some but not all metabolome perturbations at short-term follow-up.

Tong-Xie-Yao-Fang strengthens intestinal feedback control of bile acid synthesis to ameliorate irritable bowel syndrome by enhancing bile salt hydrolase-expressing microbiota

ETHNOPHARMACOLOGICAL RELEVANCE

A herbal formula Tong-Xie-Yao-Fang (TXYF) is traditionally used to treat irritable bowel syndrome (IBS), modern pharmacological evidence supports that the formula efficacy is associated with altered gut microbiota. Yet, the mechanistic role of gut microbiota in the therapy of TXYF remains unclear. We previously clarified that gut microbiota-dysregulated bile acid (BA) metabolism contribute to the pathogenesis of IBS, deriving a hypothesis that microbiota-BA metabolic axis might be a potential target of TXYF.

AIM OF THE STUDY

We aim to investigate a new gut microbiota-mediated mechanism underlying anti-IBS efficacy of TXYF.

MATERIALS AND METHODS

We established an IBS rat model with a combination of stressors, compared the herbal efficacy in models undergone gut bacterial manipulations, also examined BA metabolism-related microbiota, metabolites, genes and proteins by 16S rRNA gene sequencing, targeted metabolomics, qPCR and multiplex immunofluorescence staining.

RESULTS

We observed that TXYF attenuated visceral hyperalgesia and diarrhea in IBS rats but not in those underwent gut bacteria depletion. Transferring gut microbiota from TXYF-treated donors also decreased visceral sensitivity and slightly relief diarrhea-like behaviors in IBS recipient rats. Fecal 16S rRNA gene sequencing revealed that TXYF modulated microbial β-diversity and taxonomic structure of IBS rats, with a significant increase in relative abundance of bile salt hydrolase (BSH)-expressing Bacteroidaceae. qPCR and culturing data validated that TXYF had a promotive effect on the growth and BSH activity of Bacteroides species. TXYF-reshaped microbiota upregulated the expression of intestinal Fgf15, a feedback signal to control BA synthesis in the liver. As a result, the BA synthetic and excretory levels in IBS rats were decreased by TXYF, so as that colonic BA membrane receptor Tgr5 sensing and its mediated Calcitonin gene-related peptide (Cgrp)-positive neuronal response were attenuated.

CONCLUSION

This study poses a new microbiota-driven therapeutic action for TXYF, highlighting the potential of developing new anti-IBS strategies from the herbal formula targeting BSH-expressing gut bacteria.

Prunus persica (L.) Batsch blossom soluble dietary fiber synergia polyphenol improving loperamide-induced constipation in mice via regulating stem cell factor/C-kit, NF-κB signaling pathway and gut microbiota

This study aimed to investigate the ameliorating effects of peach blossom soluble dietary fiber (PBSDF) and polyphenol (PBP) combinations on loperamide (Lop)-induced constipation in mice, together with the possible mechanism of action. The results demonstrated that the combined use of PBSDF and PBP could synergistically accelerate the gastrointestinal transit rate and gastric emptying rate, shorten first red fecal defecation time, accelerate the frequency of defecation, regulate the abnormal secretion of gastrointestinal neurotransmitters and pro-inflammatory cytokines, and down-regulate the expressions of AQP3 and AQP8. Western blotting and RT-qPCR analysis confirmed that PBSDF + PBP up-regulated the protein and mRNA expressions of SCF and C-kit in SCF/C-kit signaling pathway, and down-regulated pro-inflammatory mediator expressions in NF-κB signaling pathway. 16S rRNA sequencing showed that the diversity of gut microbiota and the relative abundance of specific strains, including Akkermansia, Bacteroides, Ruminococcus, Lachnospiraceae_NK4A136_group, and Turicibacter, rehabilitated after PBSDF + PBP intervention. These findings suggested that the combination of a certain dose of PBSDF and PBP had a synergistic effect on attenuating Lop-induced constipation, and the synergistic mechanism in improving constipation might associated with the regulating NF-κB and SCF/C-kit signaling pathway, and modulating the specific gut strains on constipation-related systemic types. The present study provided a novel strategy via dietary fiber and polyphenol interactions for the treatment of constipation.

Gut Microbiota Regulate Saturated Free Fatty Acid Metabolism in Heart Failure

AIMS

Heart failure (HF) is associated with profound changes in cardiac metabolism. At present, there is still a lack of relevant research to explore the key microbiome and their metabolites affecting the progression of HF. Herein, the interaction of gut microbiota and circulating free fatty acid (FFA) in HF patients and mice is investigated.

METHODS AND RESULTS

In HF patients, by applying metagenomics analysis and targeted FFA metabolomics, enriched abundance of Clostridium sporogenes (C.sp) in early and late stage of HF patients, which negatively correlated to saturated free fatty acid (SFA) levels, is identified. KEGG analysis further indicates microbiota gene enrichment in FFA degradation in early HF, and decreased gene expression in FFA synthesis in late HF. In HF mice (C57BL/6J) induced by isoproterenol (ISO), impaired intestinal permeability is observed, and decreased fecal C.sp and increased SFA are further validated. At last, by supplementing C.sp to ISO-induced HF mice, the cardiac function, fibrosis, and myocardial size are partially rescued, together with decreased circulating SFA levels.

CONCLUSIONS

Clostridium abundance is increased in HF, compensating cardiac function deterioration via downregulation of circulating SFA levels. The results demonstrate that the gut microbiota-SFA axis plays an important role in HF protection, which may provide a strategic advantage for the probiotic therapy development in HF.

Recent genetic drift in the co-diversified gut bacterial symbionts of laboratory mice

Laboratory mice (Mus musculus domesticus) harbor gut bacterial strains that are distinct from those of wild mice1 but whose evolutionary histories are poorly understood. Understanding the divergence of laboratory-mouse gut microbiota (LGM) from wild-mouse gut microbiota (WGM) is critical, because LGM and WGM have been previously shown to differentially affect mouse immune-cell proliferation2,3, infection resistance4, cancer progression2, and ability to model drug outcomes for humans5. Here, we show that laboratory mice have retained gut bacterial symbiont lineages that diversified in parallel (co-diversified) with rodent species for > 25 million years, but that LGM strains of these ancestral symbionts have experienced accelerated accumulation of genetic load during the past ~ 120 years of captivity. Compared to closely related WGM strains, co-diversified LGM strains displayed significantly faster genome-wide rates of fixation of nonsynonymous mutations, indicating elevated genetic drift, a difference that was absent in non-co-diversified symbiont clades. Competition experiments in germ-free mice further indicated that LGM strains within co-diversified clades displayed significantly reduced fitness in vivo compared to WGM relatives to an extent not observed within non-co-diversified clades. Thus, stochastic processes (e.g., bottlenecks), not natural selection in the laboratory, have been the predominant evolutionary forces underlying divergence of co-diversified symbiont strains between laboratory and wild house mice. Our results show that gut bacterial lineages conserved in diverse rodent species have acquired novel mutational burdens in laboratory mice, providing an evolutionary rationale for restoring laboratory mice with wild gut bacterial strain diversity.

Duodenal microbiota dysbiosis in functional dyspepsia and its potential role of the duodenal microbiota in gut-brain axis interaction: a systematic review

Background and aims

Functional dyspepsia (FD) is a common gastrointestinal disorder associated with brain-gut interaction disturbances. In recent years, accumulating evidence points to the duodenum as a key integrator in dyspepsia symptom generation. Investigations into the pathological changes in the duodenum of FD patients have begun to focus on the role of duodenal microbiota dysbiosis. This review summarizes duodenal microbiota changes in FD patients and explores their relationship with gut-brain interaction dysregulation.

Methods

Ten databases, including PubMed, MEDLINE, and the Cochrane Library, were searched from inception to 10th October 2023 for clinical interventional and observational studies comparing the duodenal microbiota of FD patients with controls. We extracted and qualitatively summarized the alpha diversity, beta diversity, microbiota composition, and dysbiosis-related factors.

Results

A total of nine studies, consisting of 391 FD patients and 132 non-FD controls, were included. The findings reveal that the alpha diversity of the duodenal microbiota in FD patients does not exhibit a significant difference compared to non-FD controls, although an upward trend is observed. Furthermore, alterations in the duodenal microbiota of FD patients are associated with the symptom burden, which, in turn, impacts their quality of life. In FD patients, a considerable number of duodenal microbiota demonstrate a marked ascending trend in relative abundance, including taxa such as the phylum Fusobacteria, the genera Alloprevotella, Corynebacterium, Peptostreptococcus, Staphylococcus, Clostridium, and Streptococcus. A more pronounced declining trend is observed in the populations of the genera Actinomyces, Gemella, Haemophilus, Megasphaera, Mogibacterium, and Selenomonas within FD patients. A negative correlation in the relative abundance changes between Streptococcus and Prevotella is identified, which correlates with the severity of symptom burden in FD patients. Moreover, the alterations in specific microbial communities in FD patients and their potential interactions with the gut-brain axis merit significant attention.

Conclusion

Microbial dysbiosis in FD patients is linked to the onset and exacerbation of symptoms and is related to the disorder of gut-brain interaction. Larger-scale, higher-quality studies, along with comprehensive meta-omics research, are essential to further elucidate the characteristics of the duodenal microbiota in FD patients and its role in FD pathogenesis.Systematic review registration: CRD42023470279, URL: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023470279.

Effects of exoskeleton-assisted walking on bowel function in motor-complete spinal cord injury patients: involvement of the brain-gut axis, a pilot study

Evidence has demonstrated that exoskeleton robots can improve intestinal function in patients with spinal cord injury (SCI). However, the underlying mechanisms remain unelucidated. This study investigated the effects of exoskeleton-assisted walking (EAW) on intestinal function and intestinal flora structure in T2-L1 motor complete paraplegia patients. The results showed that five participants in the EAW group and three in the conventional group reported improvements in at least one bowel management index, including an increased frequency of bowel evacuations, less time spent on bowel management per day, and less external assistance (manual digital stimulation, medication, and enema usage). After 8 weeks of training, the amount of glycerol used in the EAW group decreased significantly (p <0.05). The EAW group showed an increasing trend in the neurogenic bowel dysfunction (NBD) score after 8 weeks of training, while the conventional group showed a worsening trend. Patients who received the EAW intervention exhibited a decreased abundance of Bacteroidetes and Verrucomicrobia, while Firmicutes, Proteobacteria, and Actinobacteria were upregulated. In addition, there were decreases in the abundances of Bacteroides, Prevotella, Parabacteroides, Akkermansia, Blautia, Ruminococcus 2, and Megamonas. In contrast, Ruminococcus 1, Ruminococcaceae UCG002, Faecalibacterium, Dialister, Ralstonia, Escherichia-Shigella, and Bifidobacterium showed upregulation among the top 15 genera. The abundance of Ralstonia was significantly higher in the EAW group than in the conventional group, and Dialister increased significantly in EAW individuals at 8 weeks. This study suggests that EAW can improve intestinal function of SCI patients in a limited way, and may be associated with changes in the abundance of intestinal flora, especially an increase in beneficial bacteria. In the future, we need to further understand the changes in microbial groups caused by EAW training and all related impact mechanisms, especially intestinal flora metabolites. Clinical trial registration: https://www.chictr.org.cn/.

Bifidobacterium longum S3 alleviates loperamide-induced constipation by modulating intestinal acetic acid and stearic acid levels in mice

Constipation is a major gastrointestinal (GI) symptom worldwide, with diverse causes of formation, and requires effective and safe therapeutic measures. In the present study, we used loperamide hydrochloride to establish a constipation model and assessed the effect of Bifidobacterium on constipation and its possible mechanism of relief. The results showed that B. longum S3 exerted a constipation-relieving effect primarily by improving the gut microbiota, enriching genera including Lactobacillus, Alistipes, and Ruminococcaceae UCG-007, and decreasing the bacteria Lachnospiraceae NK4B4 group. These changes may thereby increase acetic acid and stearic acid (C18:0) levels, which significantly increase the expression levels of ZO-1 and MUC-2, repair intestinal barrier damage and reduce inflammation (IL-6). Furthermore, it also inhibited oxidative stress levels (SOD and CAT), decreased the expression of water channel proteins (AQP4 and AQP8), significantly elevated the Gas, 5-HT, PGE2, and Ach levels, and reduced nNOS and VIP levels to improve the intestinal luminal transit time and fecal water content. Collectively, these changes resulted in the alleviation of constipation.

The effects of fermented vegetables on the gut microbiota for prevention of cardiovascular disease

This study investigated the impact of regular consumption of fermented vegetables (FVs) on inflammation and the composition of the gut microbiota in adults at increased risk for cardiovascular disease. Eighty-seven adults ages 35-64 were randomized into an FV group, who consumed 100 g FVs daily at least five times per week for eight weeks, or a usual diet (UD) group. Blood and stool samples were obtained before and after the intervention. Dependent samples t tests and adjusted linear models were used for within- and between-group comparisons. The mean age and body mass index of participants were 45 years and 30 kg/m2, and 80% were female. Bloating or gas was the most common side effect reported (19.3% FV group vs. 9.4% UD group). There were no changes in C-reactive protein, oxidized low-density lipoprotein-receptor 1, angiopoietin-like protein 4, trimethylamine oxide, and lipopolysaccharide-binding protein or bacterial alpha diversity between groups. Our findings indicate that consuming 100 g of FVs for at least five days per week for eight weeks does not change inflammatory biomarkers or microbial alpha diversity as measured by the Shannon index. It is possible that higher doses of FVs are necessary to elicit a significant response by gut bacteria.

Gut microbiome affects the response to immunotherapy in non-small cell lung cancer

BACKGROUND

Immunotherapy has revolutionized cancer treatment. Recent studies have suggested that the efficacy of immunotherapy can be further enhanced by the influence of gut microbiota. In this study, we aimed to investigate the impact of bacteria on the effectiveness of cancer immunotherapy by combining analysis of clinical samples with validation in animal models.

METHODS

In order to characterize the diversity and composition of microbiota and its relationship with response to immune checkpoint inhibitors (ICIs), 16S ribosomal RNA (rRNA) and GC-MS sequencing was performed on 71 stool samples from patients with advanced non-small cell lung cancer (NSCLC) prior to treatment with immune checkpoint blockade (ICB). Furthermore, fecal microbiota transplantation (FMT) was performed from different patients into mice and a subcutaneous tumor model established using the Lewis lung cancer cell line to evaluate the therapeutic effect of PD-1 on mice with varying gut microbiota.

RESULTS

The results demonstrated a significant association between elevated gut microbiota diversity and response to treatment with ICIs, p < 0.05. Faecalibacterium was markedly increased in the gut microbiota of responders (R), accompanied by increased short-chain fatty acid (SCFA) levels, especially butanoic acid, acetic acid and hexanoic acid, p < 0.05. Additionally, FMT from R and nonresponders (NR) could promote an anticancer effect and reduce the expression of Ki-67 cells in tumors in mice, p < 0.05. Moreover, R and NR FMT did not alter PD-L1 expression in the tumor tissues of mice, p > 0.05. The diversity of gut microbiota consistently correlated with an optimistic prognosis in NSCLC patients with immunotherapy, which could be functionally mediated by SCFAs.

CONCLUSION

The findings of the present study indicated that the diversity of gut microbiota and SCFAs is related to the efficacy of immunotherapy. FMT can effectively delay tumor progression, and enhance the effect of immunotherapy, thus providing evidence for improving the efficacy of immunotherapy in NSCLC patients.

Long-term intake of thermo-induced oxidized oil results in anxiety-like and depression-like behaviors: involvement of microglia and astrocytes

Frequent consumption of fried foods has been strongly associated with a higher risk of anxiety and depression, particularly among young individuals. The existing evidence has indicated that acrylamide produced from starchy foods at high temperatures can induce anxious behavior. However, there is limited research on the nerve damage caused by thermo-induced oxidized oil (TIOO). In this study, we conducted behavioral tests on mice and found that prolonged consumption of TIOO led to significant anxiety behavior and a tendency toward depression. TIOO primarily induced these two emotional disorders by affecting the differentiation of microglia, the level of inflammatory factors, the activation of astrocytes, and glutamate circulation in brain tissue. By promoting the over-differentiation of microglia into M1 microglia, TIOO disrupted their differentiation balance, resulting in an up-regulation of inflammatory factors (IL-1β, IL-6, TNF-α, NOS2) in M1 microglia and a down-regulation of neuroprotective factors IL-4/IL-10 in M2 microglia, leading to nerve damage. Moreover, TIOO activated astrocytes, accelerating their proliferation and causing GFAP precipitation, which damaged astrocytes. Meanwhile, TIOO stimulates the secretion of the BDNF and reduces the level of the glutamate receptor GLT-1 in astrocytes, leading to a disorder in the glutamate-glutamine cycle, further exacerbating nerve damage. In conclusion, this study suggests that long-term intake of thermo-induced oxidized oil can trigger symptoms of anxiety and depression.

Antibiotics and probiotics-induced effects on the total fatty acid composition of feces in a rat model

Fatty acids (FAs) play important roles as membrane components and signal transduction molecules. Changes in short chain FA (SCFA) composition are associated with gut microbiota modifications. However, the effect of bacteria-driven changes on the detailed FA spectrum has not been explored yet. We investigated the effect of antibiotics (ABx) and/or probiotics, in four treatment groups on rat stool FA composition. Principal component analysis indicated that the chromatogram profiles of the treatment groups differ, which was also observed at different time points. Linear mixed effects models showed that in the parameters compared (sampling times, treatments. and their interactions), both the weight percentage and the concentration of FAs were affected by ABx and probiotic administration. This study found that the gut microbiome defines trans and branched saturated FAs, most saturated FAs, and unsaturated FAs with less carbon atoms. These results are among the first ones to demonstrate the restoring effects of a probiotic mixture on a substantial part of the altered total FA spectrum, and also revealed a previously unknown relationship between gut bacteria and a larger group of FAs. These findings suggest that intestinal bacteria produce not only SCFAs but also other FAs that may affect the host's physiological processes.

Lacticaseibacillus rhamnosus GG Improves Periodontal Bone Repair via Gut-Blood Axis in Hyperlipidemia

Periodontal bone regeneration remains a clinical challenge, and hyperlipidemia can aggravate alveolar bone resorption. Probiotics have recently been reported to improve bone mass. We aimed to determine the role of Lacticaseibacillus rhamnosus GG (LGG) in periodontal bone regeneration improvement within the context of periodontitis with hyperlipidemia. A Sprague Dawley rat model for periodontitis, hyperlipidemia, and periodontal fenestration defect was constructed (n = 36) and administered LGG gavage for 6 wk (the rats were subsequently sacrificed). Fecal microbiota from donor rats 3 wk after LGG gavage was transplanted into recipient rats to evaluate the role of LGG-modulated gut microbiota in periodontal bone regeneration. Regenerated bone mass was detected using micro-computerized tomography and hematoxylin and eosin stain. Gut microbiota was analyzed using 16S ribosomal RNA sequencing. Serum metabolites were detected by liquid chromatography-mass spectrometry (6 wk after LGG gavage). The pro-osteogenic effects of screened serum metabolite were verified in vitro on bone marrow mesenchymal stem cells (BMMSCs). We found that the bone mineral density, bone volume (BV), trabecular bone volume fraction (BV/TV), and trabecular thickness of the regenerated periodontal bone increased after LGG gavage (P < 0.05) but had little effect on oral flora. After LGG gavage, Staphylococcus, Corynebacterium, and Collinsella in the gut of donors were significantly changed, and these differences were maintained in recipients, who also showed increased trabecular thickness of the regenerated periodontal bone (P < 0.05). These key genera were correlated with BV/TV and BV (P < 0.05). In addition, LGG gavage significantly regulated bone-related blood metabolites, of which selenomethionine promoted BMMSC osteogenesis. Notably, selenomethionine was associated with key gut genera (P < 0.05). Collectively, LGG improved periodontal bone regeneration in the context of periodontitis with hyperlipidemia by modulating gut microbiota and increasing pro-osteogenic metabolites in the blood. These results reveal new insights into the use of probiotics to promote periodontal bone regeneration via the gut-blood-bone axis.

Integrated meta-omics reveals the regulatory landscape involved in lipid metabolism between pig breeds

BACKGROUND

Domesticated pigs serve as an ideal animal model for biomedical research and also provide the majority of meat for human consumption in China. Porcine intramuscular fat content associates with human health and diseases and is essential in pork quality. The molecular mechanisms controlling lipid metabolism and intramuscular fat accretion across tissues in pigs, and how these changes in response to pig breeds, remain largely unknown.

RESULTS

We surveyed the tissue-resident cell types of the porcine jejunum, colon, liver, and longissimus dorsi muscle between Lantang and Landrace breeds by single-cell RNA sequencing. Combining lipidomics and metagenomics approaches, we also characterized gene signatures and determined key discriminating markers of lipid digestibility, absorption, conversion, and deposition across tissues in two pig breeds. In Landrace, lean-meat swine mainly exhibited breed-specific advantages in lipid absorption and oxidation for energy supply in small and large intestinal epitheliums, nascent high-density lipoprotein synthesis for reverse cholesterol transport in enterocytes and hepatocytes, bile acid formation, and secretion for fat emulsification in hepatocytes, as well as intestinal-microbiota gene expression involved in lipid accumulation product. In Lantang, obese-meat swine showed a higher synthesis capacity of chylomicrons responsible for high serum triacylglycerol levels in small intestinal epitheliums, the predominant characteristics of lipid absorption in muscle tissue, and greater intramuscular adipcytogenesis potentials from muscular fibro-adipogenic progenitor subpopulation.

CONCLUSIONS

The findings enhanced our understanding of the cellular biology of lipid metabolism and opened new avenues to improve animal production and human diseases. Video Abstract.

The Landscape of Gut Microbiota and Its Metabolites: A Key to Understanding the Pathophysiology of Pattern in Chinese Medicine

Liver Stagnation and Spleen Deficiency (LSSD) is a Chinese Medicine (CM) pattern commonly observed in gastrointestinal (GI) diseases, yet its biological nature remains unknown. This limits the global use of CM medications for treating GI diseases. Recent studies emphasize the role of gut microbiota and their metabolites in the pathogenesis and treatment of LSSD-associated GI diseases. There is increasing evidence supporting that an altered gut microbiome in LSSD patients or animals contributes to GI and extra-intestinal symptoms and affects the effectiveness of CM therapies. The gut microbiota is considered to be an essential component of the biological basis of LSSD. This study aims to provide an overview of existing research findings and gaps for the pathophysiological study of LSSD from the gut microbiota perspective in order to understand the relationship between the CM pattern and disease progression and to optimize CM-based diagnosis, prevention, and therapy.

Single-Cell Hemoprotein Diet Changes Adipose Tissue Distributions and Re-Shapes Gut Microbiota in High-Fat Diet-Induced Obese Mice

We have previously observed that feeding with single-cell hemoprotein (heme-SCP) in dogs (1 g/day for 6 days) and broiler chickens (1 ppm for 32 days) increased the proportion of lactic acid bacteria in the gut while reducing their body weights by approximately 1~2%. To define the roles of heme-SCP in modulating body weight and gut microbiota, obese C57BL/6N mice were administered varied heme-SCP concentrations (0, 0.05, and 0.5% heme-SCP in high fat diet) for 28 days. The heme-SCP diet seemed to restrain weight gain till day 14, but the mice gained weight again later, showing no significant differences in weight. However, the heme-SCP-fed mice had stiffer and oilier bodies compared with those of the control mice, which had flabby bodies and dull coats. When mice were dissected at day 10, the obese mice fed with heme-SCP exhibited a reduction in subcutaneous fat with an increase in muscle mass. The effect of heme-SCP on the obesity-associated dyslipidemia tended to be corroborated by the blood parameters (triglyceride, total cholesterol, and C-reactive protein) at day 10, though the correlation was not clear at day 28. Notably, the heme-SCP diet altered gut microbiota, leading to the proliferation of known anti-obesity biomarkers such as Akkermansia, Alistipes, Oscillibacter, Ruminococcus, Roseburia, and Faecalibacterium. This study suggests the potential of heme-SCP as an anti-obesity supplement, which modulates serum biochemistry and gut microbiota in high-fat diet-induced obese mice.

Gut dysbiosis aggravates cognitive deficits, amyloid pathology and lipid metabolism dysregulation in a transgenic mouse model of Alzheimer's disease

Gut dysbiosis, a well-known risk factor to triggers the progression of Alzheimer's disease (AD), is strongly associated with metabolic disturbance. Trimethylamine N-oxide (TMAO), produced in the dietary choline metabolism, has been found to accelerate neurodegeneration in AD pathology. In this study, the cognitive function and gut microbiota of TgCRND8 (Tg) mice of different ages were evaluated by Morris water maze task (MWMT) and 16S rRNA sequencing, respectively. Young pseudo germ-free (PGF) Tg mice that received faecal microbiota transplants from aged Tg mice and wild-type (WT) mice were selected to determine the role of the gut microbiota in the process of neuropathology. Excessive choline treatment for Tg mice was used to investigate the role of abnormal choline metabolism on the cognitive functions. Our results showed that gut dysbiosis, neuroinflammation response, Aβ deposition, tau hyperphosphorylation, TMAO overproduction and cyclin-dependent kinase 5 (CDK5)/transcription 3 (STAT3) activation occurred in Tg mice age-dependently. Disordered microbiota of aged Tg mice accelerated AD pathology in young Tg mice, with the activation of CDK5/STAT3 signaling in the brains. On the contrary, faecal microbiota transplantation from WT mice alleviated the cognitive deficits, attenuated neuroinflammation, Aβ deposition, tau hyperphosphorylation, TMAO overproduction and suppressed CDK5/STAT3 pathway activation in Tg mice. Moreover, excessive choline treatment was also shown to aggravate the cognitive deficits, Aβ deposition, neuroinflammation and CDK5/STAT3 pathway activation. These findings provide a novel insight into the interaction between gut dysbiosis and AD progression, clarifying the important roles of gut microbiota-derived substances such as TMAO in AD neuropathology.

Lactic acid bacteria in relieving constipation: mechanism, clinical application, challenge, and opportunity

Constipation is a prevalent gastrointestinal symptom that can considerably affect a patients' quality of life. Although several drugs have been used to treat constipation, they are associated with high costs, side effects, and low universality. Therefore, alternative intervention strategies are urgently needed. Traditional lactic acid bacteria (LAB), such as Bifidobacterium and Lactobacillus, play a vital role in regulating intestinal microecology and have demonstrated favorable effects in constipation; however, a comprehensive review of their constipation relief mechanisms is limited. This review summarizes the pathogenesis of constipation and the relationship between intestinal motility and gut microbiota, elucidates the possible mechanism by which LAB alleviates of constipation through a systematic summary of animal and clinical research, and highlights the challenges and applications of LAB in the treatment of constipation. Our review can improve our understanding of constipation, and advance targeted microecological therapeutic agents, such as LAB.

Delivery mode impacts gut bacteriophage colonization during infancy

Background

Cesarean section delivery is associated with altered early-life bacterial colonization and later adverse inflammatory and immune health outcomes. Although gut bacteriophages can alter gut microbiome composition and impact host immune responses, little is known about how delivery mode impacts bacteriophage colonization over time. To begin to address this we examined how delivery mode affected bacteriophage colonization over the first two years of life.

Results

Shotgun metagenomic sequencing was conducted on 272 serial stool samples from 55 infants, collected at 1-2 days of life and 2, 6, 12 and 24 months. 33/55 (60%) infants were born by vaginal delivery. DNA viruses were identified, and by host inference, 94% of the viral sequences were found to be bacteriophages. Alpha diversity of the virome was increased in vaginally delivered infants compared to cesarean section delivered infants at 2 months (Shannon index, p=0.022). Beta diversity significantly differed by delivery mode at 2, 6, and 12 months when stratified by peripartum antibiotic use (Bray-Curtis dissimilarity, all p<0.05). Significant differentially abundant predicted bacteriophage hosts by delivery mode were seen at all time points. Moreover, there were differences in predicted bacteriophage functional gene abundances up to 24 months by delivery mode. Many of the functions considered to play a role in host response were increased in vaginal delivery.

Conclusions

Clear differences in bacteriophage composition and function were seen by delivery mode over the first two years of life. Given that phages are known to affect host immune response, our results suggest that future investigation into how delivery mode may lead to adverse inflammatory outcomes should not only include bacterial microbial colonization but also the potential role of bacteriophages and transkingdom interactions.

Remote effects of kidney drug transporter OAT1 on gut microbiome composition and urate homeostasis

The organic anion transporter OAT1 (SLC22A6, originally identified as NKT) is a multispecific transporter responsible for the elimination by the kidney of small organic anions that derive from the gut microbiome. Many are uremic toxins associated with chronic kidney disease (CKD). OAT1 is among a group of "drug" transporters that act as hubs in a large homeostatic network regulating interorgan and interorganismal communication via small molecules. The Remote Sensing and Signaling Theory predicts that genetic deletion of such a key hub in the network results in compensatory interorganismal communication (e.g., host-gut microbe dynamics). Recent metabolomics data from Oat1-KO mice indicate that some of the most highly affected metabolites derive from bacterial tyrosine, tryptophan, purine, and fatty acid metabolism. Functional metagenomic analysis of fecal 16S amplicon and whole-genome sequencing revealed that loss of OAT1 was impressively associated with microbial pathways regulating production of urate, gut-derived p-cresol, tryptophan derivatives, and fatty acids. Certain changes, such as alterations in gut microbiome urate metabolism, appear compensatory. Thus, Oat1 in the kidney appears to mediate remote interorganismal communication by regulating the gut microbiome composition and metabolic capability. Since OAT1 function in the proximal tubule is substantially affected in CKD, our results may shed light on the associated alterations in gut-microbiome dynamics.

Integrative metabolome and lipidome analyses of plasma in neovascular macular degeneration

Age-related macular degeneration (AMD) causes irreversible vision-loss among the elderly in industrial countries. Neovascular AMD (nAMD), which refers to late-stage AMD, is characterized by severe vision-threatening choroidal neovascularization (CNV). Herein, we constructed a global metabolic network of nAMD, based on untargeted metabolomic and lipidomic analysis of plasma samples collected from sixty subjects (30 nAMD patients and 30 age-matched controls). Among the nAMD and control groups, 62 and 44 significantly different metabolites were detected in the positive and negative ion modes, respectively. Grouping analysis further showed that lipid and lipid-like molecule-based superclasses contained the highest number of significantly different metabolites. Lipidomic analysis revealed that 53 lipids among the nAMD and control groups differed significantly; these belonged to four major lipid categories (glycerophospholipids, sphingolipids, glycerolipids, and fatty acids). A discriminative biomarker panel comprising 16 metabolites and lipids, which was constructed using multivariate statistical machine learning methods, could effectively identify nAMD cases. Among these 16 compounds, eight were lipids that belonged to three lipid categories (glycerophospholipids, sphingolipids, and prenol lipids). The top three biomarkers with the highest importance scores were all lipids (a glycerophospholipid and two sphingolipids), highlighting the crucial role played by glycerophospholipid and sphingolipid pathways in nAMD. These differences between the metabolic and lipid profiles of nAMD patients and elderly individuals without AMD provide a readout of the overall metabolic status of nAMD. Further insights into the identified discriminative biomarkers may pave the way for future diagnostic and therapeutic interventions for nAMD.

Potential associations between organic dairy products, gut microbiome, and gut health: A review

Organic products have received longstanding, widespread attention for their nutritional and ecological benefits, as they are said to have certain positive health attributes and contain fewer harmful compounds than conventional (or non-organic) products. We reviewed the recent literature to examine potential associations between nutrient composition, gut microbiota, and gut health effects in recent comparative studies of organic and conventional dairy products. Trends of increased ratios of omega-3 to omega-6 polyunsaturated fatty acids and unsaturated to saturated fat, increased fat-soluble vitamin content, and decreased levels of certain pernicious contaminants in organic milk were observed across the studies reviewed. Studies of the metabolism of these nutrients in both in vitro and in vivo settings, and their or their metabolites' interaction with the intestinal epithelium show that nutrients enriched in organic dairy products may support host nutrient uptake and mediate gut inflammation. Research on the effects of single food products or classes of food products on gut health is rare. The extent of these benefits is highly likely to be mediated by both the magnitude of the difference in nutrient types and quantities, and by dietary intake levels of dairy products. Intervention studies directly examining the different effects of organic and conventional dairy products on gut health in humans are needed to further elucidate this relationship.

Fecal Concentrations of Long-Chain Fatty Acids, Sterols, and Unconjugated Bile Acids in Cats with Chronic Enteropathy

Chronic enteropathy (CE) in cats encompasses food-responsive enteropathy, chronic inflammatory enteropathy (or inflammatory bowel disease), and low-grade intestinal T-cell lymphoma. While alterations in the gut metabolome have been extensively studied in humans and dogs with gastrointestinal disorders, little is known about the specific metabolic profile of cats with CE. As lipids take part in energy storage, inflammation, and cellular structure, investigating the lipid profile in cats with CE is crucial. This study aimed to measure fecal concentrations of various fatty acids, sterols, and bile acids. Fecal samples from 56 cats with CE and 77 healthy control cats were analyzed using gas chromatography-mass spectrometry, targeting 12 fatty acids, 10 sterols, and 5 unconjugated bile acids. Fecal concentrations of nine targeted fatty acids and animal-derived sterols were significantly increased in cats with CE. However, fecal concentrations of plant-derived sterols were significantly decreased in cats with CE. Additionally, an increased percentage of primary bile acids was observed in a subset of cats with CE. These findings suggest the presence of lipid maldigestion, malabsorption, and inflammation in the gastrointestinal tract of cats with CE. Understanding the lipid alterations in cats with CE can provide insights into the disease mechanisms and potential future therapeutic strategies.

Lung microbiota and potential treatment of respiratory diseases

The unique microbiome found in the lungs has been studied and shown to be associated with both pulmonary homeostasis and lung diseases. The lung microbiome has the potential to produce metabolites that modulate host-microbe interactions. Specifically, short-chain fatty acids (SCFAs) produced by certain strains of the lung microbiota have been shown to regulate immune function and maintain gut mucosal health. In response, this review described the distribution and composition of the microbiota in lung diseases and discussed the impact of the lung microbiota on health and lung disease. In addition, the review further elaborated on the mechanism of microbial metabolites in microbial-host interaction and their application in the treatment of lung diseases. A better understanding of the interaction between the microbiota, metabolites, and host will provide potential strategies for the development of novel methods for the treatment of pulmonary microbial induced lung diseases.

Alteration of gut microbiota in wild-borne long-tailed macaques after 1-year being housed in hygienic captivity

The wild-born long-tailed macaques (Macaca fascicularis) were recently recruited and used as breeders for the National Primate Research Center of Thailand, Chulalongkorn University (NPRCT-CU), and changes in their in-depth gut microbiota profiles were investigated. The Oxford Nanopore Technology (ONT) was used to explore full-length 16S rDNA sequences of gut microbiota in animals once captured in their natural habitat and 1-year following translocation and housing in a hygienic environment at NPRCT-CU. Our findings show that the gut microbiota of macaques after 1 year of hygienic housing and programmed diets feeding was altered and reshaped. The prevalent gut bacteria such as Prevotella copri and Faecalibacterium prausnitzii were enriched after translocation, causing the lower alpha diversity. The correlation analysis revealed that Prevotella copri, Phascolarctobacterium succinatutens, and Prevotella stercorea, showed a positive correlation with each other. Significantly enriched pathways in the macaques after translocation included biosynthesis of essential amino acids, fatty acids, polyamine and butanoate. The effects of microbiota change could help macaques to harvest the energy from programmed diets and adapt their gut metabolism. The novel probiotics and microbiota engineering approach could be further developed based on the current findings and should be helpful for captive animal health care management.

Inflammatory crosstalk between saturated fatty acids and gut microbiota-white adipose tissue axis

PURPOSE

High-fat diets have different metabolic responses via gut dysbiosis. In this review, we discuss the complex interaction between the intake of long- and medium-chain saturated fatty acids (SFAs), gut microbiota, and white adipose tissue (WAT) dysfunction, particularly focusing on the type of fat.

RESULTS

The evidence for the impact of dietary SFAs on the gut microbiota-WAT axis has been mostly derived from in vitro and animal models, but there is now also evidence emerging from human studies. Most current reports show that, in response to high long- and medium-chain SFA diets, WAT functions are altered and can be modulated from microbial metabolites in several manners; and it appears to be also modified under conditions of obesity. SFAs overconsumption can reduce bacterial content and disrupt the gut environment. Both long- and medium-chain SFAs may contribute to proinflammatory cytokines release and TLR4 cascade signaling, either by regulation of endotoxemia markers or myristoylated protein. Palmitic and stearic acids have pathological effects on the intestinal epithelium, microbes, and inflammatory and lipogenic WAT profiles. While myristic and lauric acids display somewhat controversial outcomes, from probiotic effects and contribution to weight loss to cardiometabolic alterations from WAT inflammation.

CONCLUSION

Identifying an interference of distinct types of SFA in the binomial gut microbiota-WAT may elucidate essential mechanisms of metabolic endotoxemia, which may be the key to triggering obesity, innovating the therapeutic tools for this disease.

Fatty acid overproduction by gut commensal microbiota exacerbates obesity

Although recent studies have highlighted the impact of gut microbes on the progression of obesity and its comorbidities, it is not fully understood how these microbes promote these disorders, especially in terms of the role of microbial metabolites. Here, we report that Fusimonas intestini, a commensal species of the family Lachnospiraceae, is highly colonized in both humans and mice with obesity and hyperglycemia, produces long-chain fatty acids such as elaidate, and consequently facilitates diet-induced obesity. High fat intake altered the expression of microbial genes involved in lipid production, such as the fatty acid metabolism regulator fadR. Monocolonization with a FadR-overexpressing Escherichia coli exacerbated the metabolic phenotypes, suggesting that the change in bacterial lipid metabolism is causally involved in disease progression. Mechanistically, the microbe-derived fatty acids impaired intestinal epithelial integrity to promote metabolic endotoxemia. Our study thus provides a mechanistic linkage between gut commensals and obesity through the overproduction of microbe-derived lipids.

Metabolites from specific intestinal bacteria in vivo fermenting Lycium barbarum polysaccharide improve collagenous arthritis in rats

Rheumatoid arthritis (RA) is an autoimmune disease affected patients' quality of life severely. Our previous study found Lycium barbarum polysaccharide (LBP) alleviated RA, but it remains unknown whether gut microbiota is necessary for the alleviation. Here, RA models were established in rats with microbiota and rats treated by antibiotic cocktail, and LBP was applied for the intervention on rats. The biochemical test, 16S rDNA sequencing and metabolome analysis were applied to analyze the effects of LBP on gut microbiota, their metabolites and hosts. Results showed the LBP intervention improved RA by inhibiting pro-inflammatory cytokines IL-1α, IL-1β, TNF-α and IL-6 only in rats with microbiota, but not in pseudo-germ-free rats. The abundance of specific bacteria, including Romboutsia, Lactobacillus, Turicibacter, Clostridium_sensu_stricto_1, Faecalibacterium and Adlercreutzia, and several metabolites, including O-desmethylangolensin, 3-hydroxydodecanedioic acid, N-formyl-L-methionine, suberic acid, (S)-oleuropeic acid, prolyl-histidine, 13,14-dihydro PGF-1a, (R)-pelletierine and short-chain fatty acids increased only in RA rats with microbiota after the intervention. Our results suggest that intestinal bacteria are necessary for LBP alleviating RA alleviation. The fermentation metabolite acts on the host instead of LBP itself, which may be the reason for the improvement of RA.

Polysaccharides from Holothuria leucospilota Relieve Loperamide-Induced Constipation Symptoms in Mice

A vital bioactive component of marine resources is Holothuria leucospilota polysaccharides (HLP). This study examined whether HLP could regulate intestinal flora to treat loperamide-induced constipation. Constipated mice showed signs of prolonged defecation (up by 60.79 min) and a reduced number of bowel movements and pellet water content (decreased by 12.375 and 11.77%, respectively). The results showed that HLP treatment reduced these symptoms, reversed the changes in related protein expression levels in the colon, and regulated the levels of active peptides associated with the gastrointestinal tract in constipated mice, which significantly improved water-electrolyte metabolism and enhanced gastrointestinal motility. Meanwhile, it was found that intestinal barrier damage was reduced and the inflammatory response was inhibited through histopathology and immunohistochemistry. As a means to further relieve constipation symptoms, treatment with low, medium, and high HLP concentrations increased the total short-chain fatty acid (SCFA) content in the intestine of constipated mice by 62.60 μg/g, 138.91 μg/g, and 126.51 μg/g, respectively. Moreover, an analysis of the intestinal flora's gene for 16S rRNA suggested that the intestinal microbiota was improved through HLP treatment, which is relevant to the motivation for the production of SCFAs. In summary, it was demonstrated that HLP reduced loperamide-induced constipation in mice.

Enzyme Feed Additive with Arazyme Improve Growth Performance, Meat Quality, and Gut Microbiome of Pigs

The supplementation of pig diets with exogenous enzymes is widely used with the expectation that it will improve the efficiency of nutrient utilization, thereby, improving growth performance. This study aims to evaluate the effects of a 0.1% (v/v) multi-enzyme (a mixture of arazyme (2,500,000 Unit/kg), xylanase (200,000 Unit/kg) and mannanase (200,000 Unit/kg)) supplementation derived from invertebrate symbiotic bacteria on pig performance. Here, 256 growing pigs were assigned to control and treatment groups, respectively. The treatment group exhibited a significantly reduced average slaughter age; the final body weight and average daily gain increased compared with that of the control group. In the treatment group, the longissimus muscle showed a remarkable decrease in cooking loss, shear force, and color values with increased essential and non-essential amino acid concentrations. Furthermore, the concentrations of mono- and polyunsaturated fatty acids in the treatment group increased. Feed additive supplementation increased the family of Ruminococcaceae and genera Lactobacillus, Limosilactobacillus, Turicibacter, and Oscillibacter, which play a positive role in the host physiology and health. Predicted metabolic pathway analysis confirmed that operational taxonomic units and predicted amino acid biosynthesis pathways were strongly associated. The results suggest that applying exogenous enzymes derived from invertebrate symbiotic bacteria enhances animal performance.

Aqueous cinnamon extract ameliorates bowel dysfunction and enteric 5-HT synthesis in IBS rats

Cinnamon protects against irritable bowel syndrome with diarrhea (IBS-D) in humans, but its efficacy and underlying mechanism of action remain poorly understood. Maternally separated (MS) IBS-D rat model and 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced post-inflammatory IBS-D rat model are characterized by visceral hyperalgesia and diarrhea. This study used the two models to evaluate the effect of cinnamon extract (CE) on bowel symptoms. The MS rat model was also used to explore its underlying anti-IBS mechanism. cinnamon extract reduced defecation frequency and visceral hyperalgesia in MS rats in a dose-dependent manner and effectively improved visceral hyperalgesia in TNBS rats. The efficacy of cinnamon extract was comparable to the positive drug serotonin receptor 3 (5-HT3) selective antagonist, Ramosetron. Excessive 5-HT, a well-known pathogenic factor for IBS, in the colon and circulation of IBS rats was reduced after cinnamon extract intervention. Both, gene and protein levels of the colonic 5-HT synthetase, Tryptophan Hydroxylase 1 (Tph1), were also decreased in CE-treated IBS rats. In addition, a luciferase assay revealed that cinnamon extract and its major components, catechin, procyanidin B1/2, cinnamic acid, and cinnamyl alcohol, significantly inhibited Tph1 transcription activity in vitro. These findings illustrated that aqueous cinnamon extract partially attenuated bowel symptoms in IBS models by directly inhibiting Tph1 expression and controlling 5-HT synthesis. This provides a scientific viewpoint for the use of cinnamon as a folk medication to treat IBS.

Longitudinal multi-omics analyses of the gut-liver axis reveals metabolic dysregulation in hepatitis C infection and cirrhosis

The gut and liver are connected via the portal vein, and this relationship, which includes the gut microbiome, is described as the gut-liver axis. Hepatitis C virus (HCV) can infect the liver and cause fibrosis with chronic infection. HCV has been associated with an altered gut microbiome; however, how these changes impact metabolism across the gut-liver axis and how this varies with disease severity and time is unclear. Here we used multi-omics analysis of portal and peripheral blood, faeces and liver tissue to characterize the gut-liver axis of patients with HCV across a fibrosis severity gradient before (n = 29) and 6 months after (n = 23) sustained virologic response, that is, no detection of the virus. Fatty acids were the major metabolites perturbed across the liver, portal vein and gut microbiome in HCV, especially in patients with cirrhosis. Decreased fatty acid degradation by hepatic peroxisomes and mitochondria was coupled with increased free fatty acid (FFA) influx to the liver via the portal vein. Metatranscriptomics indicated that Anaerostipes hadrus-mediated fatty acid synthesis influences portal FFAs. Both microbial fatty acid synthesis and portal FFAs were associated with enhanced hepatic fibrosis. Bacteroides vulgatus-mediated intestinal glycan breakdown was linked to portal glycan products, which in turn correlated with enhanced portal inflammation in HCV. Paired comparison of patient samples at both timepoints showed that hepatic metabolism, especially in peroxisomes, is persistently dysregulated in cirrhosis independently of the virus. Sustained virologic response was associated with a potential beneficial role for Methanobrevibacter smithii, which correlated with liver disease severity markers. These results develop our understanding of the gut-liver axis in HCV and non-HCV liver disease aetiologies and provide a foundation for future therapies.

Neonatal corticosterone administration increases p27-positive Sertoli cell number and decreases Sertoli cell number in the testes of mice at prepuberty

Cortisol and corticosterone (CORT) are steroid, antistress hormones and one of the glucocorticoids in humans and animals, respectively. This study evaluated the effects of CORT administration on the male reproductive system in early life stages. CORT was subcutaneously injected at 0.36 (low-), 3.6 (middle-), and 36 (high-dosed) mg/kg body weight from postnatal day (PND) 1 to 10 in ICR mice. We observed a dose-dependent increase in serum CORT levels on PND 10, and serum testosterone levels were significantly increased only in high-dosed-CORT mice. Triiodothyronine levels were significantly higher in the low-dosed mice but lower in the middle- and high-dosed mice. However, testicular weights did not change significantly among the mice. Sertoli cell numbers were significantly reduced in low- and middle-dosed mice, whereas p27-positive Sertoli cell numbers increased in low- and middle-dosed mice. On PND 16, significant increases in testicular and relative testicular weights were observed in all-dosed-CORT mice. On PND 70, a significant decrease in testicular weight, Sertoli cell number, and spermatozoa count was observed. These results revealed that increased serum CORT levels in early life stages could induce p27 expression in Sertoli cells and terminate Sertoli cell proliferation, leading to decreased Sertoli cell number in mouse testes.

Relationship between gut microbiota and lymphocyte subsets in Chinese Han patients with spinal cord injury

This study is to investigate the changes of lymphocyte subsets and the gut microbiota in Chinese Han patients with spinal cord injury (SCI). We enrolled 23 patients with SCI and 21 healthy controls. Blood and fecal samples were collected. The proportion of lymphocyte subsets was detected by flow cytometry. 16S rDNA sequencing of the V4 region was used to analyze the gut microbiota. The changes of the gut microbiota were analyzed by bioinformatics. Correlation analysis between gut microbiota and lymphocyte subsets was performed. CD4 + cells, CD4 + /CD8 + ratio and CD4 + CD8 + cells in peripheral blood of SCI patients were significantly lower than those of the control group (P &lt; 0.05). There was no significant difference in B cells and CIK cells between the SCI group and the control group. The gut microbiota community diversity index of SCI patients was significantly higher than that of healthy controls. In SCI patients, the relative abundance of Lachnospiraceae (related to lymphocyte subset regulation), Ruminococcaceae (closely related to central nervous system diseases), and Escherichia-Shigella (closely related to intestinal infections) increased significantly, while the butyrate producing bacteria (Fusobacterium) that were beneficial to the gut were dramatically decreased. Correlation analysis showed that the five bacterial genera of SCI patients, including Lachnospiraceae UCG-008, Lachnoclostridium 12, Tyzzerella 3, Eubacterium eligens group, and Rumencocciucg-002, were correlated with T lymphocyte subsets and NK cells. In the SCI group, the flora Prevotella 9, Lachnospiraceae NC2004 group, Veillonella, and Sutterella were positively correlated with B cells. However, Fusobacterium and Akkermansia were negatively correlated with B cells. Moreover, Roseburia and Ruminococcaceae UCG-003 were positively correlated with CIK cells. Our results suggest that the gut microbiota of patients with SCI is associated with lymphocyte subsets. Therefore, it is possible to improve immune dysregulation in SCI patients by modulating gut microbiota, which may serve as a new therapeutic method for SCI.

Effect of Gut Microbiota on the Metabolism of Chemical Constituents of Berberis kansuensis Extract Based on UHPLC-Orbitrap-MS Technique

The dried stem bark of Berberis kansuensis is a commonly used Tibetan herbal medicine for the treatment of diabetes. Its main chemical components are alkaloids, such as berberine, magnoflorine and jatrorrhizine. However, the role of gut microbiota in the in vivo metabolism of these chemical components has not been fully elucidated. In this study, an ultra-high performance liquid chromatography method coupled with Orbitrap mass spectrometry (UHPLC-Orbitrap-MS) technology was applied to detect and identify prototype components and metabolites in rat intestinal contents and serum samples after oral administration of a B. kansuensis extract. A total of 16 prototype components and 40 metabolites were identified. The primary metabolic pathways of the chemical components from B. kansuensis extract were demethylation, desaturation, deglycosylation, reduction, hydroxylation, and other conjugation reactions including sulfation, glucuronidation, glycosidation, and methylation. By comparing the differences of metabolites between diabetic and pseudo-germ-free diabetic rats, we found that the metabolic transformation of some chemical components in B. kansuensis extract such as bufotenin, ferulic acid 4-O-β-D-glucopyranoside, magnoflorine, and 8-oxyberberine, was affected by the gut microbiota. The results revealed that the gut microbiota can affect the metabolic transformation of chemical constituents in B. kansuensis extract. These findings can enhance our understanding of the active ingredients of B. kansuensis extract and the key role of the gut microbiota on them.

Alterations in infant gut microbiome composition and metabolism after exposure to glyphosate and Roundup and/or a spore-based formulation using the SHIME technology

Despite extensive research into the toxicology of the herbicide glyphosate, there are still major unknowns regarding its effects on the human gut microbiome. We describe the effects of glyphosate and a Roundup glyphosate-based herbicide on infant gut microbiota using SHIME technology. SHIME microbiota culture was undertaken in the presence of a concentration of 100-mg/L glyphosate and the same glyphosate equivalent concentration of Roundup. Roundup and to a lesser extent glyphosate caused an increase in fermentation activity, resulting in acidification of the microbial environment. This was also reflected by an increase in lactate and acetate production concomitant to a decrease in the levels of propionate, valerate, caproate and butyrate. Ammonium production reflecting proteolytic activities was increased by Roundup exposure. Global metabolomics revealed large-scale disturbances, including an increased abundance of long-chain polyunsaturated fatty acids. Changes in bacterial composition measured by qPCR and 16S rRNA suggested that lactobacilli had their growth stimulated as a result of microenvironment acidification. Co-treatment with the spore-based probiotic formulation MegaSporeBiotic reverted some of the changes in short-chain fatty acid levels. Altogether, our results suggest that glyphosate can exert effects on human gut microbiota.

Role of gut microbiota-derived signals in the regulation of gastrointestinal motility

The gastrointestinal (GI) tract harbors trillions of commensal microbes, called the gut microbiota, which plays a significant role in the regulation of GI physiology, particularly GI motility. The GI tract expresses an array of receptors, such as toll-like receptors (TLRs), G-protein coupled receptors, aryl hydrocarbon receptor (AhR), and ligand-gated ion channels, that sense different gut microbiota-derived bioactive substances. Specifically, microbial cell wall components and metabolites, including lipopeptides, peptidoglycan, lipopolysaccharides (LPS), bile acids (BAs), short-chain fatty acids (SCFAs), and tryptophan metabolites, mediate the effect of gut microbiota on GI motility through their close interactions with the enteroendocrine system, enteric nervous system, intestinal smooth muscle, and immune system. In turn, GI motility affects the colonization within the gut microbiota. However, the mechanisms by which gut microbiota interacts with GI motility remain to be elucidated. Deciphering the underlying mechanisms is greatly important for the prevention or treatment of GI dysmotility, which is a complication associated with many GI diseases, such as irritable bowel syndrome (IBS) and constipation. In this perspective, we overview the current knowledge on the role of gut microbiota and its metabolites in the regulation of GI motility, highlighting the potential mechanisms, in an attempt to provide valuable clues for the development of gut microbiota-dependent therapy to improve GI motility.

Saccharomyces boulardii, a yeast probiotic, inhibits gut motility through upregulating intestinal serotonin transporter and modulating gut microbiota

Saccharomyces boulardii (Sb) is a widely used fungal probiotic in treating various digestive diseases, including irritable bowel syndrome (IBS). However, the specific mechanisms of Sb relieving IBS remain unclear. The abnormal serotonin transporter (SERT) / 5-hydroxytryptamine (5-HT) system could cause disordered gastrointestinal sensation and motility, which closely related to IBS pathogenesis. The aim of this study was to explore the effects and mechanisms of Sb on regulating gut motility. Sb supernatant (SbS) was administered to intestinal epithelial cells and mice. SbS upregulated SERT expression via enhancing heparin-binding epidermal growth factor (HB-EGF) release to activate epidermal growth factor receptor (EGFR). EGFR kinase inhibitor treatment or HB-EGF siRNA transfection in cells blocked SbS upregulating SERT. Consistently, SbS-treated mice presented inhibited gut motility, and EGFR activation and SERT upregulation were found. Moreover, 16 S rDNA sequence presented an evident decrease in Firmicutes / Bacteroidetes ratio in SbS group. In genus level, SbS reduced Escherichia_Shigella, Alistipes, Clostridium XlVa, and Saccharibacteria_genera_incertae_sedis, meanwhile, increased Parasutterella. The abundance of Saccharibacteria_genera_incertae_sedis positively correlated with defecation parameters and intestinal 5-HT content. Fecal microbiota transplantation showed that SbS could modulate gut microbiota to influence gut motility. Interestingly, elimination of gut microbiota with antibiotic cocktail did not entirely block SbS regulating gut motility. Furthermore, SbS administration to IBS-D mice significantly upregulated SERT and inhibited gut motility. In conclusion, SbS could upregulate SERT by EGFR activation, and modulate gut microbiota to inhibit gut motility. This finding would provide more evidence for the application of this yeast probiotic in IBS and other diarrheal disorders.

Acylation, a Conductor of Ghrelin Function in Brain Health and Disease

Acyl-ghrelin (AG) is an orexigenic hormone that has a unique octanoyl modification on its third serine residue. It is often referred to as the “hunger hormone” due to its involvement in stimulating food intake and regulating energy homeostasis. The discovery of the enzyme ghrelin-O-acyltransferase (GOAT), which catalyses ghrelin acylation, provided further insights into the relevance of this lipidation process for the activation of the growth hormone secretagogue receptor (GHS-R) by acyl-ghrelin. Although acyl-ghrelin is predominantly linked with octanoic acid, a range of saturated fatty acids can also bind to ghrelin possibly leading to specific functions. Sources of ghrelin acylation include beta-oxidation of longer chain fatty acids, with contributions from fatty acid synthesis, the diet, and the microbiome. In addition, both acyl-ghrelin and unacyl-ghrelin (UAG) have feedback effects on lipid metabolism which in turn modulate their levels. Recently we showed that whilst acyl-ghrelin promotes adult hippocampal neurogenesis and enhances memory function, UAG inhibits these processes. As a result, we postulated that the circulating acyl-ghrelin:unacyl-ghrelin (AG:UAG) ratio might be an important regulator of neurogenesis and cognition. In this review, we discuss emerging evidence behind the relevance of ghrelin acylation in the context of brain physiology and pathology, as well as the current challenges of identifying the provenance of the acyl moiety.