Alternative method for gas chromatography-mass spectrometry analysis of short-chain fatty acids in faecal samples

Quantifying fecal and plasma short-chain fatty acids in healthy Thai individuals

Short-chain fatty acids (SCFAs) are involved in important physiological processes such as gut health and immune response, and changes in SCFA levels can be indicative of disease. Despite the importance of SCFAs in human health and disease, reference values for fecal and plasma SCFA concentrations in healthy individuals are scarce. To address this gap in current knowledge, we developed a simple and reliable derivatization-free GC-TOFMS method for quantifying fecal and plasma SCFAs in healthy individuals. We targeted six linear- and seven branched-SCFAs, obtaining method recoveries of 73-88% and 83-134% in fecal and plasma matrices, respectively. The developed methods are simpler, faster, and more sensitive than previously published methods and are well suited for large-scale studies. Analysis of samples from 157 medically confirmed healthy individuals showed that the total SCFAs in the feces and plasma were 34.1 ± 15.3 µmol/g and 60.0 ± 45.9 µM, respectively. In fecal samples, acetic acid (Ace), propionic acid (Pro), and butanoic acid (But) were all significant, collectively accounting for 89% of the total SCFAs, whereas the only major SCFA in plasma samples was Ace, constituting of 93% of the total plasma SCFAs. There were no statistically significant differences in the total fecal and plasma SCFA concentrations between sexes or among age groups. The data revealed, however, a positive correlation for several nutrients, such as carbohydrate, fat, iron from vegetables, and water, to most of the targeted SCFAs. This is the first large-scale study to report SCFA reference intervals in the plasma and feces of healthy individuals, and thereby delivers valuable data for microbiome, metabolomics, and biomarker research.

New findings in the metabolism of the saffron apocarotenoids, crocins and crocetin, by the human gut microbiota

The main constituents of saffron are the apocarotenoids crocins and crocetin, present in the stigmas. Numerous healthy properties, especially those related to the effects on the central nervous system, have been attributed to these compounds but the metabolites responsible for these effects are still unknown. Previous evidences in animal models suggest a role for the gut microbiota in the pharmacokinetics and the neuroprotective effects of these compounds. However, the interaction between these apocarotenoids and the gut microbiota has been poorly studied. In this article, we have thoroughly investigated the batch fermentation of crocin-1 and crocetin (10 μM) with human fecal samples of two donors at different incubation times (0-240 h) using a metabolomic approach. We corroborated a rapid transformation of crocin-1 which looses the glucose molecules through de-glycosylation reactions until its complete transformation into crocetin in 6 hours. A group of intermediate crocins with different degrees of glycosylation were detected in a very short time. Crocetin was further metabolized and new microbial metabolites produced by double-bond reduction and demethylation reactions were identified for the first time: dihydro and tetrahydro crocetins and di-demethyl crocetin. In addition, we detected changes in the levels of the short chain fatty acids valeric acid and hexanoic acid suggesting further structural modifications of crocetin or changes in the catabolic production of these compounds. This research is a pioneering study of the action of the human gut microbiota on the saffron apocarotenoids and goes one step further towards the discovery of metabolites potentially involved in the benefits of saffron.

Characterization of Extractable and Non-Extractable Phenols and Betalains in Berrycactus (Myrtillocactus geometrizans) and Its Chemoprotective Effect in Early Stage of Colon Cancer In Vivo

This research identified the bioactive compounds and antioxidant capacity of the extractable (EP) and non-extractable (NEP) polyphenol fractions of berrycactus (BC). Additionally, the effects of BC and its residue (BCR) on preventing AOM/DSS-induced early colon carcinogenesis were evaluated in vivo. Male Sprague Dawley rats were randomly assigned to six groups (n = 12/group): healthy control (C), AOM/DSS, BC, BCR, BC+AOM/DSS, and BCR+AOM/DSS. NEP was obtained through acid hydrolysis using H2SO4 and HCl (1 M or 4 M). The HCl-NEP fraction exhibited the highest total phenolic and flavonoid content, while condensed tannins were more abundant in the H2SO4-NEP fraction. A total of 33 polyphenols were identified by UPLC-QTOF-MSE in both EP and NEP, some of which were novel to BC. Both NEP hydrolysates demonstrated significant total antioxidant capacity (TEAC), with HCl-NEP exhibiting the highest ORAC values. The BC+AOM/DSS and BCR+AOM/DSS groups exhibited fewer aberrant crypt foci (p < 0.05), reduced colonic epithelial injury, and presented lower fecal β-glucuronidase activity, when compared to AOM/DSS group. No differences in butyric acid concentrations were observed between groups. This study presents novel bioactive compounds in EP and NEP from BC that contribute to chemopreventive effects in early colon carcinogenesis, while reducing fecal β-glucuronidase activity and preserving colonic mucosal integrity.

Inclusion of sorghum (Sorghum bicolor (L). Moench) with protease and NSP-ase increases jejunal histomorphology and barrier function gene expression in broiler chickens

The objective of this study was to investigate the effect of sorghum with or without protease and NSP-ase on performance, jejunal histomorphology, caecal short-chain fatty acids (SCFA), and gene expression of barrier function in the broiler chickens. A total of 240 males New Lohmann strain MB 202 broiler chicks (1-day-old) were randomly placed into 12 treatments with 4 replications, 5 birds per replicate for 35 d. The diets were a factorial combination of 3 levels of sorghum (0, 10, and 20%), 2 concentrations of protease (with and without protease), and 2 concentrations of NSP-ase (with and without NSP-ase). Results showed that villus height (VH) was improved (P < 0.05) and villus to crypt ratio (VH:CD) tended (P = 0.05) to increase with inclusion of sorghum. Inclusion of sorghum upregulated (P < 0.05) expression of the gene anti-inflammatory IL-13, and downregulated (P < 0.05) gene of toll receptor (TLR) (TLR-3 and TLR-4), pro-inflammatory (IL-18, IL-6, tumor necrosis factor-alpha (TNF-α) and tight junction zona occluding-1 (ZO-1). The result further indicated a decrease (P < 0.05) in the concentration of SCFA. The birds fed diets with protease had lower (P < 0.05) expression of gene TLR-4 and TLR-3, pro-inflammatory (IL-6 and TNF-α), and anti-inflammatory IL-10. Inclusion of sorghum markedly (P < 0.05) interacted with protease, increasing the total of SCFA, acetate, and VH in the broiler. The bird offered diets with NSP-ase had higher (P < 0.05) expression genes of pro-inflammatory IL-18 and TNF-α. Inclusion of sorghum and NSP-ase significantly (P < 0.05) interacted, upregulating gene of tight junction ZO-1 and anti-inflammatory IL-13 but downregulating gene TLR-3, and pro-inflammatory IL-6, while the SCFA production was decreased. Inclusion of sorghum in the diet with or without enzymes did not affect broiler performance (P > 0.05). In conclusion, a diet with sorghum improved jejunal histomorphology without negatively affecting growth performance. Additionally, supplementation with enzymes enhanced intestinal immune responses by up-regulating anti-inflammatory, and downregulating pro-inflammatory gene expression.

Gut microbiota derived short-chain fatty acids in physiology and pathology: An update

Short-chain fatty acids (SCFAs) are essential molecules produced by gut bacteria that fuel intestinal cells and may also influence overall health. An imbalance of SCFAs can result in various acute and chronic diseases, including diabetes, obesity and colorectal cancer (CRC). This review delves into the multifaceted roles of SCFAs, including a brief discussion on their source and various gut-residing bacteria. Primary techniques used for detection of SCFAs, including gas chromatography, high-performance gas chromatography, nuclear magnetic resonance and capillary electrophoresis are also discussed through this article. This review study also compiles various synthesis pathways of SCFAs from diverse substrates such as sugar, acetone, ethanol and amino acids. The different pathways through which SCFAs enter cells for immune response regulation are also highlighted. A major emphasis is the discussion on diseases associated with SCFA dysregulation, such as anaemia, brain development, CRC, depression, obesity and diabetes. This includes exploring the relationship between SCFA levels across ethnicities and their connection with blood pressure and CRC. In conclusion, this review highlights the critical role of SCFAs in maintaining gut health and their implications in various diseases, emphasizing the need for further research on SCFA detection, synthesis and their potential as diagnostic biomarkers. Future studies of SCFAs will pave the way for the development of novel diagnostic tools and therapeutic strategies for optimizing gut health and preventing diseases associated with SCFA dysregulation.

Modulatory Effects of Lactobacillus paracasei-Fermented Turmeric on Metabolic Dysregulation and Gut Microbiota in High-Fat Diet-Induced Obesity in Mice

Turmeric, derived from Curcuma longa, and Lactobacillus paracasei, a lactic acid bacteria, have been studied for their potential antiobesity effects. To date, the antiobesity effects of turmeric fermented with L. paracasei have not been sufficiently investigated. This study was conducted via oral administration of 5% L. paracasei-fermented (FT) and unfermented turmeric (UT) in diet over 16 weeks using high-fat diet (HFD)-induced obese C57BL/6J mice. Results showed that the curcuminoid content of turmeric decreased following fermentation. Furthermore, FT significantly suppressed weight gain and liver and visceral adipose tissue weight and reduced plasma metabolic parameters in both the UT and FT experimental groups. The effects of FT were more noticeable than those of the unfermented form. Moreover, FT downregulated the expression of adipogenesis, lipogenesis, and inflammatory-related protein, but upregulated liver β-oxidation protein SIRT 1, PPARα, and PGC-1α in perigonadal adipose tissue. Additionally, FT ameliorated insulin resistance by activating insulin receptor pathway protein expressions in visceral adipose tissues. FT also modulated gut microbiota composition, particularly in two beneficial bacteria, Akkermansia muciniphila and Desulfovibrio, as well as two short-chain fatty acid-producing bacteria: Muribaculum intestinale and Deltaproteobacteria. Our findings indicate that the modulation effect of FT may be an important pathway for its antiobesity mechanisms.

An exploratory study of a multi-species probiotic formulation and markers of health in a real-world oncological cohort in the time of covid

INTRODUCTION

The efficacy of cancer treatments has links to the intestinal microbiome. Mucositis is a dose-limiting intestinal pro-inflammatory side effect of cancer treatments, that increases the risk of diarrhoea, mucositis, and in severe cases, febrile neutropenia.

METHODS

The effect of cancer treatments on Quality of Life (QoL) was assessed using the FACT C questionnaire that included patient wellbeing and gut adverse symptoms (e.g. diarrhoea). Participants rated faecal samples via the Bristol Stool Chart. In addition, bacterial DNA was extracted from faecal samples, sequenced, and taxonomically examined. The incidence / severity of neutropenia was assessed with white blood cell and neutrophil counts. Circulating SCFAs and plasma lipopolysaccharide (LPS) endotoxin levels were recorded and correlated to intestinal mucositis.

RESULTS

Improvement in bowel function, with reduction in constipation and or diarrhoea or absence of significant disturbance to bowel function was recorded in 85% of the participants. One participant developed febrile neutropenia and two developed bowel toxicity during the study, that was unrelated to the test formulation. No significant changes in microbiota alpha- and beta-diversity at the phylum and species levels respectively from baseline to end of study treatment was observed. None of the participants had raised plasma-endotoxin levels from baseline to the first and subsequent treatment cycles for their cancers. Probiotics in this cohort were deemed safe and tolerable. Significant improvement in emotional QoL scores (p = 0.015) was reported with increased number of chemotherapy cycles. In a related observational study of exceptional responders to chemotherapy, participants were found to have had a high intake of fruits, vegetables, and fibre possibly indicative of a more balanced intestinal microbiota.

CONCLUSION

A multi-strain probiotic formulation was safe and tolerated in this chronically ill cohort that were undergoing oncological treatment. The probiotic formulation alleviated diarrhoea, constipation and maintained stool consistency/frequency during the multiple treatments with chemotherapy and radiotherapy. Intestinal dysbiosis that is characterised by decreased microbial diversity and increased pro-inflammatory species was not observed. Probiotic supplementation may have helped reduce dysbiosis during cancer treatments. These improvements may have been critical with the observation that emotional wellbeing was significantly improved from baseline. Hence albeit that the study had limitations, the probiotic intervention provided adjunctive treatment support to the patients. What is of scientifically plausible interest is that probiotics have a long association historically with human hosts and as such ratify their inclusion offering a significant adjunctive therapeutic potential. Future studies warrant larger sample sizes, control groups and should limit recruitment to a largely homogenous group of patients.

Characterization of Eurotium cristatum Fermented Thinned Young Apple and Mechanisms Underlying Its Alleviating Impacts on Experimental Colitis

A hundred million tons of young apples are thinned and discarded in the orchard per year, aiming to increase the yield and quality of apples. We fermented thinned young apples using a potential probiotic fungus, Eurotium cristatum, which notably disrupted the microstructure of raw samples, as characterized by the scanning electron microscope. Fermentation substantially altered the metabolite profiles of samples, which are predicted to alleviate colitis via regulating inflammatory response and response to lipopolysaccharide by using network pharmacology analysis. In vivo, oral gavage of water extracts of E. cristatum fermented young apples (E.YAP) effectively alleviated DSS-induced colitis, restored the histopathology damage, reduced the levels of inflammatory cytokines, and promoted colonic expressions of tight junction proteins. Moreover, E.YAP ameliorated gut dysbacteriosis by increasing abundances of Lactobacillus,Blautia, Muribaculaceae, and Prevotellaceae_UCG-001 while inhibiting Turicibacter, Alistipes, and Desulfovibrio. Importantly, E.YAP increased colonic bile acids, such as CA, TCA, DCA, TUDCA, and LCA, thereby alleviating colitis via PXR/NF-κB signaling. Furthermore, a synbiotic combination with Limosilactobacillus reuteri WX-94, a probiotic strain isolated from feces of healthy individuals with anti-inflammatory properties, augmented anticolitis capacities of E.YAP. Our findings demonstrate that E.YAP could be a novel, potent, food-based anti-inflammatory prebiotic for relieving inflammatory injuries.

Alterations in plasma short-chain fatty acids in preadolescence children: The Hokkaido study

The purpose of this study is to explore the plasma short-chain fatty acid (SCFA) concentrations in 9-12-year-old Japanese children collected in the Hokkaido study, focusing on how factors such as age, sex, and body mass index (BMI) correlate with these levels. The Hokkaido Study on Children's Health is an ongoing longitudinal study since 2002, encompassing 20,926 pregnant women in Hokkaido Prefecture, Japan, between 2003 and 2012. We contacted 1881 children aged 9-12 born between April 2006 and January 2010, and 342 non-fasting plasma samples (boys = 181, girls = 161) were obtained from this cohort, alongside assessments of their height and weight. Plasma SCFA concentrations were determined using N,N-dimethylethylenediamine derivatization method coupled with liquid chromatography-mass spectrometry. Ethyl acetate was used to extract SCFAs from plasma, and the recovery ranged from 83 % to 108 %. Our findings indicate that acetic acid had the highest concentration across all age groups and sexes. The concentrations of butyric acid, valeric acid, and hexanoic acid increased with age, peaking in 12-year-old children. Conversely, the level of 4-hydroxy valeric acid showed a decreasing trend with increasing age groups. This study also explored the correlation between BMI and SCFA concentrations, comparatively higher level of propionic acid was observed in the overweight group. The results obtained in this study enhance our understanding of the role of SCFAs in the growth and development of children and provide a foundation for future nutritional intervention and health promotion strategies.

Disease-associated gut microbiome and metabolome changes in rats with chronic hypoxia-induced pulmonary hypertension

Background

Pulmonary hypertension (PH) is a progressive disease affecting the lung vasculature that is characterized by sustained vasoconstriction and leads to vascular remodeling. The lung microbiome contributes to PH progression, but the function of the gut microbiome and the correlation between the gut microbiome and metabolome remain unclear. We have analyzed whether chronic hypoxia-induced PH alters the rat fecal microbiota.

Purpose

We explored hypoxia-induced pulmonary hypertension model rats to find out the characteristic changes of intestinal microorganisms and metabolites of hypoxia-induced pulmonary hypertension, and provide a theoretical basis for clinical treatment.

Methods

In the current study, a chronic hypoxia-induced PH rat model was used to investigate the role of the gut microbiome and metabolome as a potential mechanism contributing to the occurrence and development of PH. 16S ribosomal ribonucleic acid (16S rRNA), short-chain fatty acid (SCFA) measurements, mass spectrometry (MS) metabolomics analysis and metatranscriptome were performed to analyze stool samples. The datasets were analyzed individually and integrated for combined analysis using bioinformatics approaches.

Results

Our results suggest that the gut microbiome and metabolome of chronic hypoxia-induced PH rats are distinct from those of normoxic rats and may thus aid in the search for new therapeutic or diagnostic paradigms for PH.

Conclusion

The gut microbiome and metabolome are altered as a result of chronic hypoxia-induced PH. This imbalanced bacterial ecosystem might play a pathophysiological role in PH by altering homeostasis.

Lactobacillus rhamnosus 069 and Lactobacillus brevis 031: Unraveling Strain-Specific Pathways for Modulating Lipid Metabolism and Attenuating High-Fat-Diet-Induced Obesity in Mice

Obesity is a global health crisis, marked by excessive fat in tissues that function as immune organs, linked to microbiota dysregulation and adipose inflammation. Investigating the effects of Lactobacillus rhamnosus SG069 (LR069) and Lactobacillus brevis SG031 (LB031) on obesity and lipid metabolism, this research highlights adipose tissue's critical immune-metabolic role and the probiotics' potential against diet-induced obesity. Mice fed a high-fat diet were treated with either LR069 or LB031 for 12 weeks. Administration of LB031 boosted lipid metabolism, indicated by higher AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) phosphorylation, and increased the M2/M1 macrophage ratio, indicating LB031's anti-inflammatory effect. Meanwhile, LR069 administration not only led to significant weight loss by enhancing lipolysis which evidenced by increased phosphorylation of hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) but also elevated Akkermansia and fecal acetic acid levels, showing the gut microbiota's pivotal role in its antiobesity effects. LR069 and LB031 exhibit distinct effects on lipid metabolism and obesity, underscoring their potential for precise interventions. This research elucidates the unique impacts of these strains on metabolic health and highlights the intricate relationship between gut microbiota and obesity, advancing our knowledge of probiotics' therapeutic potential.

Dietary honokiol supplementation improves antioxidant capacity, enhances intestinal health, and modulates cecal microbial composition and function of broiler chickens

Honokiol is a multifunctional polyphenol present in Magnolia officinalis. The effects of honokiol as a supplement in broiler chicken diets, and the underlying mechanisms, remain unclear. Therefore, the aim of the present study was to investigate the effects of honokiol on the growth performance, antioxidant capacity, and intestinal histomorphology of broiler chickens and to explore the underlying mechanisms. In total, 240 one-day-old broilers were randomly allocated to 5 dietary treatments, with 6 replicate pens and 8 birds per pen. Birds were fed a basal diet supplemented with 0 (blank control, BC), 100, 200, or 400 mg/kg honokiol (H100, H200, and H400), or 200 mg/kg bacitracin zinc (PC) for 42 d. The results showed that H200 and H400 increased body weight gain (BWG) and decreased feed conversion ratio (FCR) during the starter period (P < 0.05). H100 and H200 increased total superoxide dismutase (T-SOD) activity in the serum and decreased malondialdehyde (MDA) amount in the jejunum on d 42 (P < 0.05). Moreover, H100 increased villus height-to-crypt depth ratio in both the jejunum and ileum on d 21 (P < 0.05). PCR analysis showed that honokiol upregulated intestinal expression of glutathione peroxidase (GSH-Px) and downregulated intestinal expression of inducible nitric oxide synthase (iNOS) on d 42 (P < 0.05). The Shannon index, which represents the microbial alpha diversity, was reduced for the PC, H200, and H400 groups. Notably, honokiol treatment altered the cecal microbial community structure and promoted the enrichment of several bacteria, including Firmicutes and Lactobacillus. Higher production of short-chain fatty acids was observed in the cecal digesta of H100 birds, accompanied by an enriched glycolysis/gluconeogenesis pathway, according to the functional prediction of the cecal microbiota. This study provides evidence that honokiol improves growth performance, antioxidant capacity, and intestinal health of broiler chickens, possibly by manipulating the composition and function of the microbial community.

Urban sports fields support higher levels of soil butyrate and butyrate-producing bacteria than urban nature parks

Butyrate-producing bacteria colonise the gut of humans and non-human animals, where they produce butyrate, a short-chain fatty acid with known health benefits. Butyrate-producing bacteria also reside in soils and soil bacteria can drive the assembly of airborne bacterial communities (the aerobiome). Aerobiomes in urban greenspaces are important reservoirs of butyrate-producing bacteria as they supplement the human microbiome, but soil butyrate producer communities have rarely been examined in detail. Here, we studied soil metagenome taxonomic and functional profiles and soil physicochemical data from two urban greenspace types: sports fields (n = 11) and nature parks (n = 22). We also developed a novel method to quantify soil butyrate and characterised the in situ activity of butyrate-producing bacteria. We show that soil butyrate was higher in sports fields than nature parks and that sports fields also had significantly higher relative abundances of the terminal butyrate production genes buk and butCoAT than nature parks. Soil butyrate positively correlated with buk gene abundance (but not butCoAT). Soil moisture (r = .50), calcium (r = -.62), iron (ρ = .54), ammonium nitrogen (ρ = .58) and organic carbon (r = .45) had the strongest soil abiotic effects on soil butyrate concentrations and iron (ρ = .56) and calcium (ρ = -.57) had the strongest soil abiotic effects on buk read abundances. Overall, our findings contribute important new insights into the role of sports fields as key exposure reservoirs of butyrate producing bacteria, with important implications for the provision of microbiome-mediated human health benefits via butyrate.

Polygonatum kingianum Polysaccharides Enhance the Preventive Efficacy of Heat-Inactivated Limosilactobacillus reuteri WX-94 against High-Fat-High-Sucrose-Induced Liver Injury and Gut Dysbacteriosis

Limosilactobacillus reuteri (L. reuteri) is an efficacious probiotic that could reduce inflammation and prevent metabolic disorders. Here, we innovatively found that Polygonatum kingianum polysaccharides (PKP) promoted proliferation and increased stability of L. reuteri WX-94 (a probiotic strain showing anti-inflammation potentials) in simulated digestive fluids in vitro. PKP was composed of galactose, glucose, mannose, and arabinose. The cell-free supernatant extracted from L. reuteri cultured with PKP increased ABTS•+, DPPH•, and FRAP scavenging capacities compared with the supernatant of the medium without PKP and increased metabolites with health-promoting activities, e.g., 3-phenyllactic acid, indole-3-lactic acid, indole-3-carbinol, and propionic acid. Moreover, PKP enhanced alleviating effects of heat-inactivated L. reuteri on high-fat-high-sucrose-induced liver injury in rats via reducing inflammation and regulating expressions of protein and genes involved in fatty acid metabolism (such as HIF1-α, FAβO, CPT1, and AMPK) and fatty acid profiles in liver. Such benefits correlated with its prominent effects on enriching Lactobacillus and short-chain fatty acids while reducing Dubosiella, Fusicatenilacter, Helicobacter, and Oscillospira. Our work provides novel insights into the probiotic property of PKP and emphasizes the great potential of the inactivated L. reuteri cultured with PKP in contracting unhealthy diet-induced liver dysfunctions and gut dysbacteriosis.

Cascade Microbial Metabolism of Ferulic Acid In Vitro Fermented by the Human Fecal Inoculum

Ferulic acid (FA), predominantly existing in most cereals, can modulate the gut microbiome, but the influences of its metabolites on the microbial population and FA-transforming microorganisms are still unclear. In this study, FA and its potential phenolic metabolites were fermented in vitro for 24 h with the human fecal inoculum. A comparable short chain fatty acid (SCFA) production trend was observed in the presence and absence of substrates, suggesting limited contribution of FA mechanism to SCFA formation. Dihydroferulic acid, 3-(3,4-dihydroxyphenyl)propionic acid, and 3-(3-hydroxyphenyl)propionic acid were ascertained to be successive metabolites of FA, by tracking the intermediate variation. FA remarkably promoted the absolute abundances of total bacteria, while different metabolites affected bacterial growth of selective genera. Specific genera were identified as quantitatively correlating to the content of FA and its metabolites. Ultimately, FA-mediated gut microbiota modulation involves both the action of metabolizing microbes and the regulation effects of metabolites on bacterial growth.

L-Glutamine Substantially Improves 5-Fluorouracil-Induced Intestinal Mucositis by Modulating Gut Microbiota and Maintaining the Integrity of the Gut Barrier in Mice

SCOPE

This study investigates the potential of glutamine to mitigate intestinal mucositis and dysbiosis caused by the chemotherapeutic agent 5-fluorouracil (5-FU).

METHODS AND RESULTS

Over twelve days, Institute of Cancer Research (ICR) mice are given low (0.5 mg kg-1) or high (2 mg kg-1) doses of L-Glutamine daily, with 5-FU (50 mg kg-1) administered between days six and nine. Mice receiving only 5-FU exhibited weight loss, diarrhea, abnormal cell growth, and colonic inflammation, correlated with decreased mucin proteins, increased endotoxins, reduced fecal short-chain fatty acids, and altered gut microbiota. Glutamine supplementation counteracted these effects by inhibiting the Toll-like receptor 4/nuclear factor kappa B (TLR4/NF-κB) pathway, modulating nuclear factor erythroid 2-related factor 2/heme oxygenase 1 (Nrf2/HO-1) oxidative stress proteins, and increasing mammalian target of rapamycin (mTOR) levels, thereby enhancing microbial diversity and protecting intestinal mucosa.

CONCLUSIONS

These findings underscore glutamine's potential in preventing 5-FU-induced mucositis by modulating gut microbiota and inflammation pathways.

Short-term exposures to PM2.5, PM2.5 chemical components, and antenatal depression: Exploring the mediating roles of gut microbiota and fecal short-chain fatty acids

BACKGROUND

PM2.5 and its chemical components increase health risks and are associated with depression and gut microbiota. However, there is still limited evidence on whether gut microbiota and short-chain fatty acids (SCFAs) mediate the association between PM2.5, PM2.5 chemical components, and antenatal depression. The purpose of this study was to investigate the mediating role of maternal gut microbiota in correlations between short-term exposure to PM2.5, short-term exposure to PM2.5 chemical components, and antenatal depression.

METHODS

Demographic information and stool samples were collected from 75 pregnant women in their third trimester. Their exposure to PM2.5 and PM2.5 chemical components was measured. Participants were divided into the non-antenatal depression group or the antenatal depression group according to the cut-off of 10 points on the Edinburgh Postnatal Depression Scale (EPDS). The gut microbiota were analyzed using the 16 S rRNA-V3/V4 gene sequence, and the concentration of PM2.5 and its chemical components was calculated using the Tracking Air Pollution in China (TAP) database. Gas chromatography-mass spectrometry was used to analyze SCFAs in stool samples. In order to assess the mediating effects of gut microbiota and SCFAs, mediation models were utilized.

RESULTS

There were significant differences between gut microbial composition and SCFAs concentrations between the non-antenatal depression group and the antenatal depression group. PM2.5 and its chemical components were positively associated with EPDS scores and negatively associated with genera Enterococcus and Enterobacter. Genera Candidatus_Soleaferrea (β = -7.21, 95%CI -11.00 to -3.43, q = 0.01) and Enterococcus (β = -2.37, 95%CI -3.87 to -0.87, q = 0.02) were negatively associated with EPDS scores, indicating their potential protective effects against antenatal depression. There was no significant association between SCFAs and EPDS scores. The mediating role of Enterococcus between different lagged periods of PM2.5, PM2.5 chemical component exposure, and antenatal depression was revealed. For instance, Enterococcus explained 29.23% (95%CI 2.16-87.13%, p = 0.04) of associations between PM2.5 exposure level at the day of sampling (lag 0) and EPDS scores.

CONCLUSION

Our study highlights that Enterococcus may mediate the associations between PM2.5, PM2.5 chemical components, and antenatal depression. The mediating mechanism through which the gut microbiota influences PM2.5-induced depression in pregnant women still needs to be further studied.

Measurement of short-chain fatty acids in human plasma by means of fast gas chromatography-mass spectrometry

A rapid and practicable analytical method for the measurement of short-chain fatty acids (SCFAs) in human plasma was developed. The extraction procedure involved the use of acidified water and methyl tert-butyl ether (MTBE), while the separation and detection of SCFAs, including acetic, propionic, and butyric acids was carried out by using gas chromatography-mass spectrometry (GC-MS) technique. The novelty of the research involves reducing the analysis time (less than 7 min) by using the novel fast GC-MS method. A narrow-bore GC capillary column of dimensions 30 m × 0.25 mm ID × 0.25 μm df with acid-modified poly(ethylene glycol) stationary phase was employed for the chromatographic separation. The signals of target compounds were acquired in selected ion monitoring (SIM) mode monitoring a quantifier ion (Q) and two qualifier ions (q1 and q2). Linearity of the method, limits of detection (LoD) and quantification (LoQ) were evaluated. In detail, regression coefficients of the calibration curves were between 0.9960 and 0.9933; LoDs ranged from 0.02 μM to 0.03 μM, while LoQs from 0.06 μM to 0.10 μM.

Aspartame Intake Delayed Puberty Onset in Female Offspring Rats and Girls

SCOPE

The disturbance of the hypothalamic-pituitary-gonadal (HPG) axis, gut microbiota (GM) community, and short-chain fatty acids (SCFAs) is a triggering factor for pubertal onset. The study investigates the effects of the long-term intake of aspartame on puberty and GM in animals and humans.

METHODS AND RESULTS

Aspartame-fed female offspring rats result in vaginal opening time prolongation, serum estrogen reduction, and serum luteinizing hormone elevation. , 60 mg kg-1 aspartame treatment decreases the mRNA levels of gonadotropin-releasing hormone (GnRH), Kiss1, and G protein-coupled receptor 54 (GPR54), increases the mRNA level of RFamide-related peptide-3 (RFRP-3), and decreases the expression of GnRH neurons in the hypothalamus. Significant differences in relative bacterial abundance at the genus levels and decreased fecal SCFA levels are noted by 60 mg kg-1 aspartame treatment. Among which, Escherichia-Shigella is negatively correlated with several SCFAs. In girls, high-dose aspartame consumption decreases the risk of precocious puberty.

CONCLUSIONS

Aspartame reduces the chance of puberty occurring earlier than usual in female offspring and girls. Particularly, 60 mg kg-1 aspartame-fed female offspring delays pubertal onset through the dysregulation of HPG axis and GM composition by inhibiting the Kiss1/GPR54 system and inducing the RFRP-3. An acceptable dose of aspartame should be recommended during childhood.

Rebaudioside D decreases adiposity and hepatic lipid accumulation in a mouse model of obesity

Overconsumption of added sugars has been pointed out as a major culprit in the increasing rates of obesity worldwide, contributing to the rising popularity of non-caloric sweeteners. In order to satisfy the growing demand, industrial efforts have been made to purify the sweet-tasting molecules found in the natural sweetener stevia, which are characterized by a sweet taste free of unpleasant aftertaste. Although the use of artificial sweeteners has raised many concerns regarding metabolic health, the impact of purified stevia components on the latter remains poorly studied. The objective of this project was to evaluate the impact of two purified sweet-tasting components of stevia, rebaudioside A and D (RebA and RebD), on the development of obesity, insulin resistance, hepatic health, bile acid profile, and gut microbiota in a mouse model of diet-induced obesity. Male C57BL/6 J mice were fed an obesogenic high-fat/high-sucrose (HFHS) diet and orally treated with 50 mg/kg of RebA, RebD or vehicle (water) for 12 weeks. An additional group of chow-fed mice treated with the vehicle was included as a healthy reference. At weeks 10 and 12, insulin and oral glucose tolerance tests were performed. Liver lipids content was analyzed. Whole-genome shotgun sequencing was performed to profile the gut microbiota. Bile acids were measured in the feces, plasma, and liver. Liver lipid content and gene expression were analyzed. As compared to the HFHS-vehicle treatment group, mice administered RebD showed a reduced weight gain, as evidenced by decreased visceral adipose tissue weight. Liver triglycerides and cholesterol from RebD-treated mice were lower and lipid peroxidation was decreased. Interestingly, administration of RebD was associated with a significant enrichment of Faecalibaculum rodentium in the gut microbiota and an increased secondary bile acid metabolism. Moreover, RebD decreased the level of lipopolysaccharide-binding protein (LBP). Neither RebA nor RebD treatments were found to impact glucose homeostasis. The daily consumption of two stevia components has no detrimental effects on metabolic health. In contrast, RebD treatment was found to reduce adiposity, alleviate hepatic steatosis and lipid peroxidation, and decrease LBP, a marker of metabolic endotoxemia in a mouse model of diet-induced obesity.

Next-generation prebiotics: Maillard-conjugates of 2'-fucosyllactose and lactoferrin hydrolysates beneficially modulate gut microbiome composition and health promoting activity in a murine model

Current prebiotics are predominantly carbohydrates. However, great competition exists among gut microbes for the scarce protein in the colon, as most consumed protein is digested and absorbed in the small intestine. Herein we evaluated in-vivo novel next-generation prebiotics: protein-containing-prebiotics, for selectively-targeted delivery of protein to colonic probiotics, to boost their growth. This system is based on micellar-particles, composed of Maillard-glycoconjugates of 2'-Fucosyllactose (2'-FL, human-milk-oligosaccharide) shell, engulfing lactoferrin peptic-then-tryptic hydrolysate (LFH) core. This core-shell structure lowers protein-core digestibility, while the prebiotic glycans are hypothesized to serve as molecular-recognition ligands for selectively targeting probiotics. To study the efficacy of this novel prebiotic, we fed C57BL/6JRccHsd mice with either 2'-FL-LFH Maillard-glycoconjugates, unconjugated components (control), or saline (blank). Administration of 2'-FL-LFH significantly increased the levels of short-chain-fatty-acids (SCFAs)-producing bacterial families (Ruminococcaceae, Lachnospiraceae) and genus (Odoribacter) and the production of the health-related metabolites, SCFAs, compared to the unconjugated components and to saline. The SCFAs-producing genus Prevotella significantly increased upon 2'-FL-LFH consumption, compared to only moderate increase in the unconjugated components. Interestingly, the plasma-levels of inflammation-inducing lipopolysaccharides (LPS), which indicate increased gut-permeability, were significantly lower in the 2'-FL-LFH group compared to the unconjugated-components and the saline groups. We found that Maillard-glycoconjugates of 2'-FL-LFH can serve as novel protein-containing prebiotics, beneficially modulating gut microbial composition and its metabolic activity, thereby contributing to host health more effectively than the conventional carbohydrate-only prebiotics.

Enhancing recovery from gut microbiome dysbiosis and alleviating DSS-induced colitis in mice with a consortium of rare short-chain fatty acid-producing bacteria

The human gut microbiota is a complex community comprising hundreds of species, with a few present in high abundance and the vast majority in low abundance. The biological functions and effects of these low-abundant species on their hosts are not yet fully understood. In this study, we assembled a bacterial consortium (SC-4) consisting of B. paravirosa, C. comes, M. indica, and A. butyriciproducens, which are low-abundant, short-chain fatty acid (SCFA)-producing bacteria isolated from healthy human gut, and tested its effect on host health using germ-free and human microbiota-associated colitis mouse models. The selection also favored these four bacteria being reduced in abundance in either Ulcerative Colitis (UC) or Crohn's disease (CD) metagenome samples. Our findings demonstrate that SC-4 can colonize germ-free (GF) mice, increasing mucin thickness by activating MUC-1 and MUC-2 genes, thereby protecting GF mice from Dextran Sodium Sulfate (DSS)-induced colitis. Moreover, SC-4 aided in the recovery of human microbiota-associated mice from DSS-induced colitis, and intriguingly, its administration enhanced the alpha diversity of the gut microbiome, shifting the community composition closer to control levels. The results showed enhanced phenotypes across all measures when the mice were supplemented with inulin as a dietary fiber source alongside SC-4 administration. We also showed a functional redundancy existing in the gut microbiome, resulting in the low abundant SCFA producers acting as a form of insurance, which in turn accelerates recovery from the dysbiotic state upon the administration of SC-4. SC-4 colonization also upregulated iNOS gene expression, further supporting its ability to produce an increasing number of goblet cells. Collectively, our results provide evidence that low-abundant SCFA-producing species in the gut may offer a novel therapeutic approach to IBD.

Simulated gastrointestinal digestion of polylactic acid (PLA) biodegradable microplastics and their interaction with the gut microbiota

The accumulation of microplastics (MPs) in the environment as well as their presence in foods and humans highlight the urgent need for studies on the effects of these particles on humans. Polylactic acid (PLA) is the most widely used bioplastic in the food industry and medical field. Despite its biodegradability, biocompatibility, and "Generally Recognized As Safe" (GRAS) status, recent animal model studies have shown that PLA MPs can alter the intestinal microbiota; however, to date, no studies have been reported on the possible gut and health consequences of its intake by humans. This work simulates the ingestion of a realistic daily amount of PLA MPs and their pass through the gastrointestinal tract by combining the INFOGEST method and the gastrointestinal simgi® model to evaluate possible effects on the human colonic microbiota composition (16S rRNA gene sequencing analysis) and metabolic functionality (lactic acid and short-chain fatty acids (SCFA) production). Although PLA MPs did not clearly alter the microbial community homeostasis, increased Bifidobacterium levels tended to increase in presence of millimetric PLA particles. Furthermore, shifts detected at the functional level suggest an alteration of microbial metabolism, and a possible biotransformation of PLA by the human microbial colonic community. Raman spectroscopy and field emission scanning electron microscopy (FESEM) characterization revealed morphological changes on the PLA MPs after the gastric phase of the digestion, and the adhesion of organic matter as well as a microbial biofilm, with surface biodegradation, after the intestinal and colonic phases. With this evidence and the emerging use of bioplastics, understanding their impact on humans and potential biodegradation through gastrointestinal digestion and the human microbiota merits critical investigation.

Application of omics technology to investigate the mechanism underlying the role of San Hua Tang in regulating microglia polarization and blood-brain barrier protection following ischemic stroke

ETHNOPHARMACOLOGY RELEVANCE

San Hua Tang (SHT) was first mentioned in the book "The Collection of Plain Questions about Pathogenesis, Qi, and Life." SHT has the effect of dispelling wind and dredging collaterals, dredging viscera, and guiding stagnation, and is used in the treatment of ischemic stroke (IS). SHT is composed of Rheum palmatum L., Magnolia officinalis Rehder & E.H.Wilson, Citrus assamensis S.Dutta & S.C.Bhattacharya, and Notopterygium tenuifolium M.L.Sheh & F.T.Pu, which is the traditional prescription of the Tongxia method for the treatment of stroke. Tongxia is one of the "eight methods" used in traditional Chinese medicine, which plays a role in treating diseases by promoting gastrointestinal peristalsis and defecation. Studies have demonstrated a close relationship between gut microbiota metabolism and cerebral stroke; however, the role of SHT in IS treatment through gut microbiota or intestinal metabolites is unclear.

AIM OF THE STUDY

To explore the connotation of the Xuanfu theory and clarify the mechanism underlying SHT-mediated opening Xuanfu methods. Through metabolomics, 16S rRNA gene sequencing, and molecular biology techniques, research on the changes in the gut microbiota and blood-brain barrier (BBB) will highlight greater strategies for the treatment of stroke.

MATERIALS AND METHODS

We used pseudo-germ-free (PGF) rats combined with an ischemia/reperfusion (I/R) rat model for the follow-up experimental research. PGF rats were prepared by the intragastric administration of an antibiotic cocktail for 6 days, following which SHT was administered for 5 consecutive days. The I/R model was performed 1 day following the concluding administration of SHT. We detected the neurological deficit score, cerebral infarct volume, serum inflammatory factor levels (interleukin IL-6, IL-10, IL-17, and tumor necrosis factor alpha), tight junction-related proteins (Zonula occludens-1, Occludin, and Claudin-5), and small glue plasma cell-associated proteins (Cluster of Differentiation 16/Cluster of Differentiation 206, Matrix metalloproteinase, ionized calcium-binding adapter molecule 1, and C-X3-C Motif Chemokine Ligand 1) 24 h following I/R. Using 16S rRNA gene sequencing and non-targeted metabolomics analysis, we explored the relationship between fecal microecology and serum metabolites. Eventually, we analyzed the correlation between the gut microbiota and plasma metabolic profile as well as the mechanism underlying the SHT-mediated regulation of gut microbiota to protect the BBB following stroke.

RESULTS

In IS treatment, SHT is principally involved in reducing neurological injury and the volume of cerebral infarction; protecting the intestinal mucosal barrier; increasing the levels of acetic acid, butyric acid, and propionic acid; promoting the transformation of microglia to the M2 state; reducing inflammatory reactions; and enhancing tight junctions. These therapeutic effects were not observed in the group treated with antibiotics alone or that treated with SHT in combination with antibiotics, thereby indicating SHT plays a therapeutic role through the gut microbiota.

CONCLUSION

SHT regulates the gut microbiota, inhibits pro-inflammatory factors in rats with IS, alleviates an inflammatory injury of the BBB, and plays a protective role in the brain.

Fecal Microbiota Transplantation from Aged Mice Render Recipient Mice Resistant to MPTP-Induced Nigrostriatal Degeneration Via a Neurogenesis-Dependent but Inflammation-Independent Manner

Accumulating data support a crucial role of gut microbiota in Parkinson's disease (PD). However, gut microbiota vary with age and, thus, will affect PD in an age-dependent, but unknown manner. We examined the effects of fecal microbiota transplantation (FMT) pretreatment, using fecal microbiota from young (7 weeks) or aged mice (23 months), on MPTP-induced PD model. Motor function, pathological changes, striatal neurotransmitters, neuroinflammation, gut inflammation and gut permeability were examined. Gut microbiota composition and metabolites, namely short-chain fatty acids (SCFAs), were analyzed. Neurogenesis was also evaluated by measuring the number of doublecortin-positive (DCX+) neurons and Ki67-positive (Ki67+) cells in the hippocampus. Expression of Cd133 mRNA, a cellular stemness marker, in the hippocampus was also examined. Mice who received FMT from young mice showed MPTP-induced motor dysfunction, and reduction of striatal dopamine (DA), dopaminergic neurons and striatal tyrosine hydroxylase (TH) levels. Interestingly and unexpectedly, mice that received FMT from aged mice showed recovery of motor function and rescue of dopaminergic neurons and striatal 5-hydroxytryptamine (5-HT), as well as decreased DA metabolism after MPTP challenge. Further, they showed improved metabolic profiling and a decreased amount of fecal SCFAs. High-throughput sequencing revealed that FMT remarkably reshaped the gut microbiota of recipient mice. For instance, levels of genus Akkermansia and Candidatus Saccharimonas were elevated in fecal samples of recipient mice receiving aged microbiota (AM + MPTP mice) than YM + MPTP mice. Intriguingly, both young microbiota and aged microbiota had no effect on neuroinflammation, gut inflammation or gut permeability. Notably, AM + MPTP mice showed a marked increase in DCX+ neurons, as well as Ki67+ cells and Cd133 expression in the hippocampal dentate gyrus (DG) compared to YM + MPTP mice. These results suggest that FMT from aged mice augments neurogenesis, improves motor function and restores dopaminergic neurons and neurotransmitters in PD model mice, possibly through increasing neurogenesis.

Host-microbiota relationship in the pathophysiology of aseptic abscess syndrome: protocol for a multicentre case-control study (ABSCESSBIOT)

INTRODUCTION

Aseptic abscess (AA) syndrome is a rare disease whose pathophysiology is unknown. It is often associated with inflammatory bowel disease and characterised by sterile inflammation with collections of neutrophils affecting several organs, especially the spleen. Microbiota are known to influence local and systemic immune responses, and both gut and oral microbiota perturbations have been reported in diseases associated with AA syndrome. However, interactions between these factors have never been studied in AA syndrome. The purpose of this translational case-control study (ABSCESSBIOT) is to investigate gut and/or oral microbiota in patients with AA syndrome compared with healthy controls. Moreover, microbiota associated metabolites quantification and Treg/Th17 balance characterisation will give a mechanistic insight on how microbiota may be involved in the pathophysiology of AA syndrome.

METHODS AND ANALYSIS

This French multicentre case-control study including 30 French centres (University hospital or regional hospital) aims to prospectively enrol 30 patients with AA syndrome with 30 matched controls and to analyse microbiota profiling (in stools and saliva), microbial metabolites quantification in stools and circulating CD4+ T cell populations.

ETHICS AND DISSEMINATION

This study protocol was reviewed and approved by an independent French regional review board (n° 2017-A03499-44, Comité de Protection des Personnes Ile de France 1) on 10 October 2022, and declared to the competent French authority (Agence Nationale de Sécurité du Médicament et des produits de santé, France). Oral and written informed consent will be obtained from each included patient and the control participant. Study results will be reported to the scientific community at conferences and in peer-reviewed scientific journals.

TRIAL REGISTRATION NUMBER

Clinical Trials web-based platform (NCT05537909).

Grape Polyphenols May Prevent High-Fat Diet-Induced Dampening of the Hypothalamic-Pituitary-Adrenal Axis in Male Mice

Context 

Chronic high-fat diet (HFD) consumption causes obesity associated with retention of bile acids (BAs) that suppress important regulatory axes, such as the hypothalamic-pituitary-adrenal axis (HPAA). HFD impairs nutrient sensing and energy balance due to a dampening of the HPAA and reduced production and peripheral metabolism of corticosterone (CORT).

Objective

We assessed whether proanthocyanidin-rich grape polyphenol (GP) extract can prevent HFD-induced energy imbalance and HPAA dysregulation.

Methods

Male C57BL6/J mice were fed HFD or HFD supplemented with 0.5% w/w GPs (HFD-GP) for 17 weeks.

Results

GP supplementation reduced body weight gain and liver fat while increasing circadian rhythms of energy expenditure and HPAA-regulating hormones, CORT, leptin, and PYY. GP-induced improvements were accompanied by reduced mRNA levels of Il6, Il1b, and Tnfa in ileal or hepatic tissues and lower cecal abundance of Firmicutes, including known BA metabolizers. GP-supplemented mice had lower concentrations of circulating BAs, including hydrophobic and HPAA-inhibiting BAs, but higher cecal levels of taurine-conjugated BAs antagonistic to farnesoid X receptor (FXR). Compared with HFD-fed mice, GP-supplemented mice had increased mRNA levels of hepatic Cyp7a1 and Cyp27a1, suggesting reduced FXR activation and more BA synthesis. GP-supplemented mice also had reduced hepatic Abcc3 and ileal Ibabp and Ostβ, indicative of less BA transfer into enterocytes and circulation. Relative to HFD-fed mice, CORT and BA metabolizing enzymes (Akr1d1 and Srd5a1) were increased, and Hsd11b1 was decreased in GP supplemented mice.

Conclusion

GPs may attenuate HFD-induced weight gain by improving hormonal control of the HPAA and inducing a BA profile with less cytotoxicity and HPAA inhibition, but greater FXR antagonism.

Effects of Fetal Growth Restriction on Postnatal Gut Microbiota in a Rat Model

OBJECTIVE

Fetal growth restriction (FGR) indicates increased risks of lifestyle-related diseases in adulthood. Previous studies showed the association between human gut dysbiosis and various diseases. However, reports examining the relationship between FGR and gut microbiota are scarce. Herein, we hypothesized that FGR may cause gut dysbiosis and analyzed the gut microbiota in a FGR rat model by restricting maternal protein intake during pregnancy.

METHODS

The FGR group was developed by feeding pregnant Sprague Dawley rats a diet containing 7% protein until birth. Control rats were fed 21% protein. Fecal samples of 2-11-week-old pups were collected weekly. DNA was extracted from each sample and subjected to polymerase chain reaction (PCR) amplification and sequencing. Additionally, short-chain fatty acids in the cecum were analyzed at 2 weeks of age, when there were differences in the occupancy of the gut microbiota.

RESULTS

Comparative analysis of the gut microbiota showed differences only at 2 weeks of age. Verrucomicrobia was significantly more abundant in the control group ( q < 0.1), whereas pathogenic bacteria, including Enterococcus and Enterobacteriaceae , tended to increase in the FGR group. The abundance of acetic and butyric acid-producing bacteria also differed between groups. Acetic acid in the cecum was considerably decreased in the FGR group, while butyric acid was increased compared to that in the control group.

CONCLUSIONS

Normalizing the alteration of FGR on postnatal gut microbiota may have beneficial effects for the host, since the FGR group caused gut dysbiosis.

Determination of short-chain fatty acids as putative biomarkers of cancer diseases by modern analytical strategies and tools: a review

Short-chain fatty acids (SCFAs) are the main metabolites produced by bacterial fermentation of non-digestible carbohydrates in the gastrointestinal tract. They can be seen as the major flow of carbon from the diet, through the microbiome to the host. SCFAs have been reported as important molecules responsible for the regulation of intestinal homeostasis. Moreover, these molecules have a significant impact on the immune system and are able to affect inflammation, cardiovascular diseases, diabetes type II, or oncological diseases. For this purpose, SCFAs could be used as putative biomarkers of various diseases, including cancer. A potential diagnostic value may be offered by analyzing SCFAs with the use of advanced analytical approaches such as gas chromatography (GC), liquid chromatography (LC), or capillary electrophoresis (CE) coupled with mass spectrometry (MS). The presented review summarizes the importance of analyzing SCFAs from clinical and analytical perspective. Current advances in the analysis of SCFAs focused on sample pretreatment, separation strategy, and detection methods are highlighted. Additionally, it also shows potential areas for the development of future diagnostic tools in oncology and other varieties of diseases based on targeted metabolite profiling.

Short-chain fatty and carboxylic acid changes associated with fecal microbiota transplant communally influence microglial inflammation

The intestinal microbiota has been proposed to influence human mental health and cognition through the gut-brain axis. Individuals experiencing recurrent Clostridioides difficile infection (rCDI) frequently report depressive symptoms, which are improved after fecal microbiota transplantation (FMT); however, mechanisms underlying this association are poorly understood. Short-chain fatty acids and carboxylic acids (SCCA) produced by the intestinal microbiota cross the blood brain barrier and have been proposed to contribute to gut-brain communication. We hypothesized that changes in serum SCCA measured before and after successful FMT for rCDI influences the inflammatory response of microglia, the resident immune cells of the central nervous system. Serum SCCA were quantified using gas chromatography-mass spectroscopy from 38 patients who participated in a randomized trial comparing oral capsule-vs colonoscopy-delivered FMT for rCDI, and quality of life was assessed by SF-36 at baseline, 4, and 12 weeks after FMT treatment. Successful FMT was associated with improvements in mental and physical health, as well as significant changes in a number of circulating SCCA, including increased butyrate, 2-methylbutyrate, valerate, and isovalerate, and decreased 2-hydroxybutyrate. Primary cultured microglia were treated with SCCA and the response to a pro-inflammatory stimulus was measured. Treatment with a combination of SCCA based on the post-FMT serum profile, but not single SCCA species, resulted in significantly reduced inflammatory response including reduced cytokine release, reduced nitric oxide release, and accumulation of intracellular lipid droplets. This suggests that both levels and diversity of SCCA may be an important contributor to gut-brain communication.

In Vitro Biotransformation and Anti-Inflammatory Activity of Constituents and Metabolites of Filipendula ulmaria

(1) Background: Filipendula ulmaria (L.) Maxim. (Rosaceae) (meadowsweet) is widely used in phytotherapy against inflammatory diseases. However, its active constituents are not exactly known. Moreover, it contains many constituents, such as flavonoid glycosides, which are not absorbed, but metabolized in the colon by gut microbiota, producing potentially active metabolites that can be absorbed. The aim of this study was to characterize the active constituents or metabolites. (2) Methods: A F. ulmaria extract was processed in an in vitro gastrointestinal biotransformation model, and the metabolites were characterized using UHPLC-ESI-QTOF-MS analysis. In vitro anti-inflammatory activity was evaluated by testing the inhibition of NF-κB activation, COX-1 and COX-2 enzyme inhibition. (3) Results: The simulation of gastrointestinal biotransformation showed a decrease in the relative abundance of glycosylated flavonoids such as rutin, spiraeoside and isoquercitrin in the colon compartment, and an increase in aglycons such as quercetin, apigenin, naringenin and kaempferol. The genuine as well as the metabolized extract showed a better inhibition of the COX-1 enzyme as compared to COX-2. A mix of aglycons present after biotransformation showed a significant inhibition of COX-1. (4) Conclusions: The anti-inflammatory activity of F. ulmaria may be explained by an additive or synergistic effect of genuine constituents and metabolites.

Early Probiotic Supplementation of Healthy Term Infants with Bifidobacterium longum subsp. infantis M-63 Is Safe and Leads to the Development of Bifidobacterium-Predominant Gut Microbiota: A Double-Blind, Placebo-Controlled Trial

Bifidobacteria are important intestinal bacteria that provide a variety of health benefits in infants. We investigated the efficacy and safety of Bifidobacterium longum subsp. infantis (B. infantis) M-63 in healthy infants in a double-blind, randomized, placebo-controlled trial. Healthy term infants were given B. infantis M-63 (n = 56; 1 × 109 CFU/day) or placebo (n = 54) from postnatal age ≤ 7 days to 3 months. Fecal samples were collected, and fecal microbiota, stool pH, short-chain fatty acids, and immune substances were analyzed. Supplementation with B. infantis M-63 significantly increased the relative abundance of Bifidobacterium compared with the placebo group, with a positive correlation with the frequency of breastfeeding. Supplementation with B. infantis M-63 led to decreased stool pH and increased levels of acetic acid and IgA in the stool at 1 month of age compared with the placebo group. There was a decreased frequency of defecation and watery stools in the probiotic group. No adverse events related to test foods were observed. These results indicate that early supplementation with B. infantis M-63 is well tolerated and contributes to the development of Bifidobacterium-predominant gut microbiota during a critical developmental phase in term infants.

Endogenous small intestinal microbiome determinants of transient colonisation efficiency by bacteria from fermented dairy products: a randomised controlled trial

BACKGROUND

The effects of fermented food consumption on the small intestine microbiome and its role on host homeostasis are largely uncharacterised as our knowledge on intestinal microbiota relies mainly on faecal samples analysis. We investigated changes in small intestinal microbial composition and functionality, short chain fatty acid (SCFA) profiles, and on gastro-intestinal (GI) permeability in ileostomy subjects upon the consumption of fermented milk products.

RESULTS

We report the results from a randomised, cross-over, explorative study where 16 ileostomy subjects underwent 3, 2-week intervention periods. In each period, they consumed either milk fermented by Lacticaseibacillus rhamnosus CNCM I-3690, or milk fermented by Streptococcus thermophilus CNCM I-1630 and Lactobacillus delbrueckii subsp. bulgaricus CNCM I-1519, or a chemically acidified milk (placebo) daily. We performed metataxonomic, metatranscriptomic analysis, and SCFA profiling of ileostomy effluents as well as a sugar permeability test to investigate the microbiome impact of these interventions and their potential effect on mucosal barrier function. Consumption of the intervention products impacted the overall small intestinal microbiome composition and functionality, mainly due to the introduction of the product-derived bacteria that reach in several samples 50% of the total microbial community. The interventions did not affect the SCFA levels in ileostoma effluent, or gastro-intestinal permeability and the effects on the endogenous microbial community were negligible. The impact on microbiome composition was highly personalised, and we identified the poorly characterised bacterial family, Peptostreptococcaceae, to be positively associated with a low abundance of the ingested bacteria. Activity profiling of the microbiota revealed that carbon- versus amino acid-derived energy metabolism of the endogenous microbiome could be responsible for the individual-specific intervention effects on the small intestine microbiome composition and function, reflected also on urine microbial metabolites generated through proteolytic fermentation.

CONCLUSIONS

The ingested bacteria are the main drivers of the intervention effect on the small intestinal microbiota composition. Their transient abundance level is highly personalised and influenced by the energy metabolism of the ecosystem that is reflected by its microbial composition ( http://www.

CLINICALTRIALS

gov , ID NCT NCT02920294). Video Abstract.

Evaluation of Pediococcus acidilacticiAS185 as an adjunct culture in probiotic cheddar cheese manufacture

A novel probiotic Pediococcus acidilactici AS185, isolated from traditional Chinese fermented foods, was used as an adjunct culture for probiotic cheddar cheese production. The physicochemical composition, textural, free amino acids (FAAs), short-chain fatty acids (SCFAs) profiles, sensory properties, and microbial survival, was evaluated during the 90-day ripening period. The addition of P. acidilactici AS185 did not influence the physicochemical composition of cheddar cheese but significantly decreased the hardness without affecting its textural profile. During ripening, P. acidilactici AS185 was able to grow and promote the generation of FAAs and SCFAs, but did not alter the overall sensory properties; it rather improved the flavor and taste of cheese. In addition, the cheese matrix protected strain P. acidilactici AS185 during transit throughout the simulated gastrointestinal system. These results demonstrated that P. acidilactici AS185 adjunct cultures might be useful for producing high-quality probiotic cheddar cheese.

Fecal Microbiota, Forage Nutrients, and Metabolic Responses of Horses Grazing Warm- and Cool-Season Grass Pastures

Integrating warm-season grasses into cool-season equine grazing systems can increase pasture availability during summer months. The objective of this study was to evaluate effects of this management strategy on the fecal microbiome and relationships between fecal microbiota, forage nutrients, and metabolic responses of grazing horses. Fecal samples were collected from 8 mares after grazing cool-season pasture in spring, warm-season pasture in summer, and cool-season pasture in fall as well as after adaptation to standardized hay diets prior to spring grazing and at the end of the grazing season. Random forest classification was able to predict forage type based on microbial composition (accuracy: 0.90 ± 0.09); regression predicted forage crude protein (CP) and non-structural carbohydrate (NSC) concentrations (p < 0.0001). Akkermansia and Clostridium butyricum were enriched in horses grazing warm-season pasture and were positively correlated with CP and negatively with NSC; Clostridum butyricum was negatively correlated with peak plasma glucose concentrations following oral sugar tests (p ≤ 0.05). These results indicate that distinct shifts in the equine fecal microbiota occur in response different forages. Based on relationships identified between the microbiota, forage nutrients, and metabolic responses, further research should focus on the roles of Akkermansia spp. and Clostridium butyricum within the equine hindgut.

Determination of polyamines in urine via electrospun nanofibers-based solid-phase extraction coupled with GC-MS and application to gastric cancer patients

The simultaneous determination of polyamines and their metabolites in urine samples was achieved by gas chromatography-mass spectrometry in the selected ion monitoring mode. After conjugating with the ion-pair reagent bis-2-ethylhexylphosphate in the aqueous phase, the polyamines in the samples were extracted with polystyrene nanofiber-based packed-fiber solid-phase extraction followed by a derivatization step using pentafluoropropionyl anhydride. With optimal conditions, all analytes were separated well. For analytes of putrescine, cadaverine, N-acetylputrescine, and N-acetylcadaverine, the linearity was good in the range of 0.05-500 μmol/L (R²  ≥ 0.993). While for spermidine, spermine, acetylspermidine, N⁸ -acetylspermidine, and N-acetylspermine, the linearity was good in the range of 0.5-500 μmol/L (R²  ≥ 0.990). The recoveries of three spiked concentrations (0.5, 5, 300 μmol/L) were 85.6%-108.4%, and relative standard deviations for intra- and interday were in the range of 2.9%-13.4% and 4.5%-15.1%, respectively. The method was successfully applied to the analysis of urine samples of gastric cancer patients. The results showed that the levels of most polyamines and N-acetylated polyamines from the patient group were significantly higher than those from the control group. The altered concentrations of the above-mentioned metabolites suggest their role in the pathogenesis of gastric cancer, and they should be further evaluated as potential markers of gastric cancer.

Bacteroides uniformis and its preferred substrate, α-cyclodextrin, enhance endurance exercise performance in mice and human males

Although gut microbiota has been linked to exercise, whether alterations in the abundance of specific bacteria improve exercise performance remains ambiguous. In a cross-sectional study involving 25 male long-distance runners, we found a correlation between Bacteroides uniformis abundance in feces and the 3000-m race time. In addition, we administered flaxseed lignan or α-cyclodextrin as a test tablet to healthy, active males who regularly exercised in a randomized, double-blind, placebo-controlled study to increase B. uniformis in the gut (UMIN000033748). The results indicated that α-cyclodextrin supplementation improved human endurance exercise performance. Moreover, B. uniformis administration in mice increased swimming time to exhaustion, cecal short-chain fatty acid concentrations, and the gene expression of enzymes associated with gluconeogenesis in the liver while decreasing hepatic glycogen content. These findings indicate that B. uniformis enhances endurance exercise performance, which may be mediated by facilitating hepatic endogenous glucose production.

Gut Bacterial Indole-3-acetic Acid Induced Immune Promotion Mediates Preventive Effects of Fu Brick Tea Polyphenols on Experimental Colitis

Ulcerative colitis has been consistently associated with gut microbiota imbalance and disturbed immune system. Emerging research suggests a protective function of polyphenols on prevention and treatment of ulcerative colitis, yet underlying mechanisms remain unclear. Fu brick tea, a postfermented tea, contains abundant polyphenols with anti-inflammatory and antioxidant properties. In the present study, we found that prophylactic supplementation of polyphenols extracted from Fu brick tea (FBTP) dose-dependently alleviated colitis symptoms, immune cells infiltration, and pro-inflammatory cytokines secretion in mice suffering dextran sulfate sodium induced murine colitis. FBTP substantially reshaped gut microbiota and promoted microbial transformation of tryptophan into indole-3-acetic acid (I3A), thereafter leading to aryl hydrocarbon receptor (AHR)-mediated protection from colitis through enhanced expressions of IL-22 and tight junction proteins (i.e., ZO-1, occluding and claudin-1) in colon. Multiomics integration analyses revealed strong connections between I3A, tryptophan-metabolizing bacteria, AHR activity, and pathological phenotypes of colitis. Notably, FBTP failed to significantly alleviate colitis symptoms in the absence of gut microbiota, while intragastric administration of I3A could imitate benefits of FBTP on colitis alleviation and intestinal epithelial homeostasis through a direct enhancement in AHR activity in microbiota-depleted mice. These findings further determine the key role of gut microbiota controlled I3A-AHR signaling in mediating the FBTP on colitis alleviation. This study provides the first data proposing the FBTP as a natural prebiotic for colitis alleviation through the gut microbiota-dependent modulation of the AHR pathway. Most importantly, we also identified I3A as a key microbial metabolite targeted by FBTP for exhibiting health-promoting effects.

Effects of periodontal pathogen-induced intestinal dysbiosis on transplant immunity in an allogenic skin graft model

Periodontal disease can induce dysbiosis, a compositional and functional alteration in the microbiota. Dysbiosis induced by periodontal disease is known to cause systemic inflammation and may affect transplant immunity. Here, we examined the effects of periodontal disease-related intestinal dysbiosis on transplant immunity using a mouse model of allogenic skin graft in which the mice were orally administered the periodontal pathogen Porphyromonas gingivalis (Pg). For 6 weeks, the Pg group orally received Pg while the control group orally received phosphate-buffered saline solution. After that, both groups received allogenic skin grafts. 16 s rRNA analysis of feces revealed that oral administration of Pg significantly increased three short chain fatty acids (SCFAs) producing genera. SCFA (acetate and propionate) levels were significantly higher in the Pg group (p = 0.040 and p = 0.005). The ratio of regulatory T cells, which are positively correlated with SCFAs, to total CD4+ T cells in the peripheral blood and spleen was significantly greater (p = 0.002 and p < 0.001) in the Pg group by flowcytometry. Finally, oral administration of Pg significantly prolonged skin graft survival (p < 0.001) and reduced pathological inflammation in transplanted skin grafts. In conclusion, periodontal pathogen-induced intestinal dysbiosis may affect transplant immunity through increased levels of SCFAs and regulatory T cells. (198 words).

Prediction of high fecal propionate-to-butyrate ratios using 16S rRNA-based detection of bacterial groups with liquid array diagnostics

Butyrate and propionate represent two of three main short-chain fatty acids produced by the intestinal microbiota. In healthy populations, their levels are reportedly equimolar, whereas a deviation in their ratio has been observed in various diseased cohorts. Monitoring such a ratio represents a valuable metric; however, it remains a challenge to adopt short-chain fatty acid detection techniques in clinical settings because of the volatile nature of these acids. Here we aimed to estimate short-chain fatty acid information indirectly through a novel, simple quantitative PCR-compatible assay (liquid array diagnostics) targeting a limited number of microbiome 16S markers. Utilizing 15 liquid array diagnostics probes to target microbiome markers selected by a model that combines partial least squares and linear discriminant analysis, the classes (normal vs high propionate-to-butyrate ratio) separated at a threshold of 2.6 with a prediction accuracy of 96%.

Probiotic supplementation for neonates with congenital gastrointestinal surgical conditions: guidelines for future research

Our pilot RCT found that probiotic supplementation with the three-strain bifidobacterial product (B. breve M-16V, B. longum subsp. infantis M-63 and B. longum subsp. longum BB536) attenuates gut dysbiosis, increases stool short-chain fatty acid (SCFA) levels and improves the growth of head circumference in neonates with congenital gastrointestinal surgical conditions (CGISC). In this article, we have provided guidelines for designing future multicentre RCTs based on the experience gained from our pilot RCT. The recommendations include advice about sample size, potential confounders, outcomes of interest, probiotic strain selection, storage, dose, duration and microbial quality assurance, collection of stool samples, storage and analysis and reporting. Following these guidelines will increase the validity of future RCTs in this area and hence confidence in their results. IMPACT: Probiotic supplementation attenuates gut dysbiosis, increases stool short-chain fatty acid (SCFA) levels and improves the growth of head circumference in neonates with congenital gastrointestinal surgical conditions. The current review provides evidence-based guidelines to conduct adequately powered RCTs in this field.

Comparing Transgenic Production to Supplementation of ω-3 PUFA Reveals Distinct But Overlapping Mechanisms Underlying Protection Against Metabolic and Hepatic Disorders

We compared endogenous ω-3 PUFA production to supplementation for improving obesity-related metabolic dysfunction. Fat-1 transgenic mice, who endogenously convert exogenous ω-6 to ω-3 PUFA, and wild-type littermates were fed a high-fat diet and a daily dose of either ω-3 or ω-6 PUFA-rich oil for 12 wk. The endogenous ω-3 PUFA production improved glucose intolerance and insulin resistance but not hepatic steatosis. Conversely, ω-3 PUFA supplementation fully prevented hepatic steatosis but failed to improve insulin resistance. Both models increased hepatic levels of ω-3 PUFA-containing 2-monoacylglycerol and N-acylethanolamine congeners, and reduced levels of ω-6 PUFA-derived endocannabinoids with ω-3 PUFA supplementation being more efficacious. Reduced hepatic lipid accumulation associated with the endocannabinoidome metabolites EPEA and DHEA, which was causally demonstrated by lower lipid accumulation in oleic acid-treated hepatic cells treated with these metabolites. While both models induced a significant fecal enrichment of the beneficial Allobaculum genus, mice supplemented with ω-3 PUFA displayed additional changes in the gut microbiota functions with a significant reduction of fecal levels of the proinflammatory molecules lipopolysaccharide and flagellin. Multiple-factor analysis identify that the metabolic improvements induced by ω-3 PUFAs were accompanied by a reduced production of the proinflammatory cytokine TNFα, and that ω-3 PUFA supplementation had a stronger effect on improving the hepatic fatty acid profile than endogenous ω-3 PUFA. While endogenous ω-3 PUFA production preferably improves glucose tolerance and insulin resistance, ω-3 PUFA intake appears to be required to elicit selective changes in hepatic endocannabinoidome signaling that are essential to alleviate high-fat diet-induced hepatic steatosis.

Eurotium cristatum reduces obesity by alleviating gut microbiota dysbiosis and modulating lipid and energy metabolism

BACKGROUND

Fuzhuan brick tea (FBT) has been shown to prevent obesity, but little is known about the effect of Eurotium cristatum, a critical fungus from FBT. This study examined the effects of live E. cristatum on lipid metabolism and gut microbiota composition in high-fat (HF) diet-induced obese mice.

RESULTS

Male HF diet-fed mice were treated with E. cristatum for 12 weeks. The results showed that E. cristatum administration caused strong inhibition against HF-induced body weight gain, dyslipidemia and liver oxidative stress damage. Additionally, Firmicutes and Bacteroidetes in phylum level and six types of bacterial including short-chain fatty acids (SCFAs) producing bacteria in genus level were found to be significantly changed in E. cristatum treated mice as compared to HF fed mice. As expected, E. cristatum could increase total SCFAs levels in feces. Interestingly, E. cristatum markedly increased the proportion of Akkermansia to resist obesity. Functional prediction analysis indicated that E. cristatum changed lipid and energy metabolism. Furthermore, E. cristatum ingestion can modulate hepatic acetyl-coa carboxylase (ACC), fatty acid synthase (FAS), sterol-regulatory element binding protein-1 (SREBP-1) and adipose uncoupling protein-1 (UCP-1) expression.

CONCLUSION

Conclusively, these findings suggest that E. cristatum can prevent the HF-induced lipid accumulation and other complications by modulating gut microbiota, lipid and energy metabolism. © 2022 Society of Chemical Industry.

Microbiota Dysbiosis and Gut Barrier Dysfunction Associated with Non-Alcoholic Fatty Liver Disease Are Modulated by a Specific Metabolic Cofactors' Combination

The gut is a selective barrier that not only allows the translocation of nutrients from food, but also microbe-derived metabolites to the systemic circulation that flows through the liver. Microbiota dysbiosis occurs when energy imbalances appear due to an unhealthy diet and a sedentary lifestyle. Dysbiosis has a critical impact on increasing intestinal permeability and epithelial barrier deterioration, contributing to bacterial and antigen translocation to the liver, triggering non-alcoholic fatty liver disease (NAFLD) progression. In this study, the potential therapeutic/beneficial effects of a combination of metabolic cofactors (a multi-ingredient; MI) (betaine, N-acetylcysteine, L-carnitine, and nicotinamide riboside) against NAFLD were evaluated. In addition, we investigated the effects of this metabolic cofactors' combination as a modulator of other players of the gut-liver axis during the disease, including gut barrier dysfunction and microbiota dysbiosis. Diet-induced NAFLD mice were distributed into two groups, treated with the vehicle (NAFLD group) or with a combination of metabolic cofactors (NAFLD-MI group), and small intestines were harvested from all animals for histological, molecular, and omics analysis. The MI treatment ameliorated gut morphological changes, decreased gut barrier permeability, and reduced gene expression of some proinflammatory cytokines. Moreover, epithelial cell proliferation and the number of goblet cells were increased after MI supplementation. In addition, supplementation with the MI combination promoted changes in the intestinal microbiota composition and diversity, as well as modulating short-chain fatty acids (SCFAs) concentrations in feces. Taken together, this specific combination of metabolic cofactors can reverse gut barrier disruption and microbiota dysbiosis contributing to the amelioration of NAFLD progression by modulating key players of the gut-liver axis.

Effect of Resistant Dextrin on Intestinal Gas Homeostasis and Microbiota

Previous studies have shown that a resistant dextrin soluble fibre has prebiotic properties with related health benefits on blood glucose management and satiety. Our aim was to demonstrate the effects of continuous administration of resistant dextrin on intestinal gas production, digestive sensations, and gut microbiota metabolism and composition. Healthy subjects (n = 20) were given resistant dextrin (14 g/d NUTRIOSE^®, Roquette Frères, Lestrem, France) for four weeks. Outcomes were measured before, at the beginning, end, and two weeks after administration: anal evacuations of gas during daytime; digestive perception, girth, and gas production in response to a standard meal; sensory and digestive responses to a comfort meal; volume of colonic biomass by magnetic resonance; taxonomy and metabolic functions of fecal microbiota by shotgun sequencing; metabolomics in urine. Dextrin administration produced an initial increase in intestinal gas production and gas-related sensations, followed by a subsequent decrease, which magnified after discontinuation. Dextrin enlarged the volume of colonic biomass, inducing changes in microbial metabolism and composition with an increase in short chain fatty acids-producing species and modulation of bile acids and biotin metabolism. These data indicate that consumption of a soluble fibre induces an adaptative response of gut microbiota towards fermentative pathways with lower gas production.

Evaluation of a Zingiber officinale and Bixa orellana Supplement on the Gut Microbiota of Male Athletes: A Randomized Placebo-Controlled Trial

The gut microbiota has emerged as a factor that influences exercise performance and recovery. The present study aimed to test the effect of a polyherbal supplement containing ginger and annatto called "ReWin(d)" on the gut microbiota of recreational athletes in a pilot, randomized, triple-blind, placebo-controlled trial. Thirty-four participants who practice physical activity at least three times weekly were randomly allocated to two groups, a ReWin(d) group or a maltodextrin (placebo) group. We evaluated the gut microbiota, the production of short-chain fatty acids, and the serum levels of interleukin-6 and lipopolysaccharide at baseline and after 4 weeks. Results showed that ReWin(d) supplementation slightly increased gut microbiota diversity. Pairwise analysis revealed an increase in the relative abundance of Lachnospira (β-coefficient = 0.013; p = 0.001), Subdoligranulum (β-coefficient = 0.016; p = 0.016), Roseburia (β-coefficient = 0.019; p = 0.001), and Butyricicoccus (β-coefficient = 0.005; p = 0.035) genera in the ReWin(d) group, and a decrease in Lachnoclostridium (β-coefficient = - 0.008; p = 0.009) and the Christensenellaceae R7 group (β-coefficient = - 0.010; p < 0.001). Moreover, the Christensenellaceae R-7 group correlated positively with serum interleukin-6 (ρ = 0.4122; p = 0.032), whereas the Lachnospira genus correlated negatively with interleukin-6 (ρ = - 0.399; p = 0.032). ReWin(d) supplementation had no effect on short-chain fatty acid production or on interleukin-6 or lipopolysaccharide levels.

Octenyl Succinic Anhydride-Modified Starch Attenuates Body Weight Gain and Changes Intestinal Environment of High-Fat Diet-Fed Mice

Effects of octenylsuccinate (OS) starch on body composition and intestinal environment in high-fat diet-fed mice were investigated. C57BL/6J mice were treated with a regular-fat (RF) diet, a high-fat (HF) diet, or a high-fat diet supplemented with OS starch (HFOSS). Fecal short-chain fatty acids (SCFAs) were quantified using gas chromatography, and the fecal microbiota profile was analyzed by 16S rDNA sequencing. One-way ANOVA and metastats analysis were performed for statistical analysis. After 22 weeks of feeding, mice in the HFOSS group had significantly lower body weight, body fat, liver weight, and cumulative food intake than those in the HF group but higher than that of the RF group. Fecal total SCFA, acetic, propionic, and butyric acid concentrations were significantly higher in the HFOSS group than that in the HF and RF groups. OS starch intervention increased the relative abundance of Parabacteroides, Alistipes, and Ruminiclostridium_5 and decreased that of Tyzzerella, Oscillibacter, Desulfovibrio, and Anaerotruncus compared with the RF and HF groups. The relative abundance of Lachnospiraceae_UCG-006 in the HFOSS group was lower than that in the HF group but higher than that in the RF group. In conclusion, OS starch prevents fat accumulation in high-fat diet-fed mice and might provide potential health benefits due to its fermentability in the gut and its ability to regulate gut microbial community structure.

Cranberry polyphenols and agave agavins impact gut immune response and microbiota composition while improving gut barrier function, inflammation, and glucose metabolism in mice fed an obesogenic diet

The consumption of plant-based bioactive compounds modulates the gut microbiota and interacts with the innate and adaptive immune responses associated with metabolic disorders. The present study aimed to evaluate the effect of cranberry polyphenols (CP), rich in flavonoids, and agavins (AG), a highly branched agave-derived neo-fructans, on cardiometabolic response, gut microbiota composition, metabolic endotoxemia, and mucosal immunomodulation of C57BL6 male mice fed an obesogenic high-fat and high-sucrose (HFHS) diet for 9 weeks. Interestingly, CP+AG-fed mice had improved glucose homeostasis. Oral supplementation with CP selectively and robustly (five-fold) increases the relative abundance of Akkermansia muciniphila, a beneficial bacteria associated with metabolic health. AG, either alone or combined with CP (CP+AG), mainly stimulated the glycan-degrading bacteria Muribaculum intestinale, Faecalibaculum rodentium, Bacteroides uniformis, and Bacteroides acidifaciens. This increase of glycan-degrading bacteria was consistent with a significantly increased level of butyrate in obese mice receiving AG, as compared to untreated counterparts. CP+AG-supplemented HFHS-fed mice had significantly lower levels of plasma LBP than HFHS-fed controls, suggesting blunted metabolic endotoxemia and improved intestinal barrier function. Gut microbiota and derived metabolites interact with the immunological factors to improve intestinal epithelium barrier function. Oral administration of CP and AG to obese mice contributed to dampen the pro-inflammatory immune response through different signaling pathways. CP and AG, alone or combined, increased toll-like receptor (TLR)-2 (Tlr2) expression, while decreasing the expression of interleukin 1ß (ILß1) in obese mice. Moreover, AG selectively promoted the anti-inflammatory marker Foxp3, while CP increased the expression of NOD-like receptor family pyrin domain containing 6 (Nlrp6) inflammasome. The intestinal immune system was also shaped by dietary factor recognition. Indeed, the combination of CP+AG significantly increased the expression of aryl hydrocarbon receptors (Ahr). Altogether, both CP and AG can shape gut microbiota composition and regulate key mucosal markers involved in the repair of epithelial barrier integrity, thereby attenuating obesity-associated gut dysbiosis and metabolic inflammation and improving glucose homeostasis.

Cold exposure, gut microbiota, and hypertension: A mechanistic study

Cold exposure has been recognized as an important risk factor for hypertension, and altered gut microbiota has been reported to be associated with hypertension. We hypothesized that there is a plausible relationship between gut microbiota and cold-induced hypertension (CIH). Therefore, we explored the potential link between the gut microbiota and its metabolites with CIH. Male Sprague-Dawley (SD) rats were randomly divided into the normal temperature group (NT, 20 ± 2 °C) and the cold exposure group (CE, 4 ± 1 °C), and faecal bacteria cross-transplantation was performed after six weeks. We analyzed the gut microbiota of rats using the 16S rDNA sequence and measured the blood pressure of rats and the content of short-chain fatty acids in rat faeces. After six weeks of cold exposure, the CIH rat model was successfully established. The cold exposure reduced the diversity of the gut microbiota, increased the abundance of potentially pathogenic and conditionally pathogenic bacteria (e.g., Quinella, Rothia, and Senegalimassilia genera), and reduced the abundance of beneficial bacteria (e.g., Lactobacillus genus) and butyric acid-producing bacteria (e.g., Lachnospiraceae UCG-008 and Ruminococcaceae UCG-013 genera). Faecal bacteria cross-transplantation altered gut microbiota composition and regulated blood pressure levels. The NT group rats transplanted with CIH rats' faecal bacteria were enriched with certain conditional pathogenic bacteria such as Prevotellaceae UCG-003 genus. The CIH rats transplanted with faecal bacteria from the NT group rats were enriched with beneficial bacteria such as Bacteroides genus. In addition, we found a significant reduction in butyric acid levels in CIH rats, which may be related to the increase in blood pressure. In conclusion, CIH is associated with altered gut microbiota and reduced butyric acid. Our findings provide novel insights for the prevention and treatment of CIH by modulating the gut microbiota through supplementation of beneficial bacteria/butyrate.