Fecal Metabolome Research Articles

P135 Mixed probiotics containing Bifidobacterium longum and its metabolites inhibit the formation of NLRP3 inflammasomes by suppressing GBP5 expression in macrophages in ulcerative colitis

Abstract Background Ulcerative Colitis (UC) is a non-specific chronic inflammation of the intestine. As an intestinal disease with a gradually increasing incidence in recent years and increasingly valued by medical staff, UC has a close relationship with intestinal flora. At present, domestic and foreign guidelines point out that probiotics can be used to induce remission in ulcerative colitis, but there are no clear instructions on the selection of probiotics, the use of dosage forms, and the dosage of probiotics, and there is a lack of relevant clinical and basic research. This study aims to explore the distinct therapeutic effects of mixed probiotics and individual strains of probiotics (Bifidobacterium longum), as well as elucidate the underlying mechanisms responsible for these variations. Methods A total of 90 patients with ulcerative colitis (UC) were enrolled in our center, who were subsequently divided into three groups: control group, single strain probiotic group (Bifidobacterium longum), and mixed probiotic group. After three months of adjuvant probiotic therapy, serum and fecal samples were collected for comparative analysis of therapeutic effects using ELISA and fecal 16s rDNA and metabolome sequence analysis. Mixed probiotic and Bifidobacterium longum were cultured in BHIs in an anaerobic chamber. The supernatant obtained after bacterial cultivation was subjected to metabolome sequence analysis. Human colonic organoids and Caco-2 cells were co-cultured with mixed probiotic and Bifidobacterium longum subsequent to inflammation induction, and cytotoxicity, permeability, and inflammatory cytokine release were assessed. THP1 cells were also to co-cultured with mixed probiotic and Bifidobacterium longum, and expression of virulence genes was analyzed using RT-qPCR, transcriptome sequencing, and western blot. GBP5 gene manipulated cell and mouse model were used to evaluate inflammation and apoptosis. Results The utilization of mixed probiotic therapy in patients with UC demonstrated significantly superior therapeutic efficacy compared to those receiving a single strain probiotic (Bifidobacterium longum). Differential metabolite 8-Deoxylactucinwas identified among various groups through the metabolome sequence analysis of clinical patients’ feces, bacterial culture supernatant, and mouse feces. Through in vitro and in vivo experiments, it has been demonstrated that 8-Deoxylactucin exhibits inhibitory effects on the expression of GBP5 in THP-1 cells and ameliorates inflammation. Conclusion Collectively, these findings indicate that mixed probiotics and its metabolites suppress GBP5 expression in macrophages in ulcerative colitis.

Analysis of the Fecal Metabolomic Profile in Breast vs. Different Formula Milk Feeding in Late Preterm Infants.

Human milk is the gold standard for infant nutrition, but when it is not available or insufficient to satisfy the needs of the infant, formula milk is proposed as an effective substitute. A prospective observational cohort study was conducted on late preterm infants fed with breast and two different formula milks. On this basis, they were divided into three groups: group FMPB (fed with formula + postbiotic), group FM (fed with standard formula), and group BM (breastfed). Stool samples for a metabolomic study were collected at T0 (5-7 days after birth), T1 (30 days of life), and T2 (90 days of life), giving rise to 74 samples analyzed via liquid chromatography coupled with high-resolution mass spectrometry. The T0, T1, and T2 LC-MS raw data were processed for Partial Least Square Discriminant Analysis (PLS-DA), followed by a statistical analysis. This preliminary study highlighted a good overlapping between the fecal metabolome of breast and substitute feeding systems, confirming the efficacy of the formula preparations as breast milk substitutes. Moreover, several similarities were also detected between the FMPB and BM metabolome, highlighting that the addition of a postbiotic to standard formula milk could be more effective and considered a better alternative to breast milk.

Temporal stability of fecal metabolomic profiles in irritable bowel syndrome.

The potential of the fecal metabolome to serve as a biomarker for irritable bowel syndrome (IBS) depends on its stability over time. Therefore, this study aimed to determine the temporal dynamics of the fecal metabolome, and the potential relationship with stool consistency, in patients with IBS and healthy subjects. Fecal samples were collected in two cohorts comprising patients with IBS and healthy subjects. For Cohort A, fecal samples collected during 5 consecutive days were analyzed by gas chromatography-tandem mass spectrometry (GC-MS/MS). For Cohort B, liquid chromatography-MS (LC-MS) was used to analyze fecal samples collected at week 0 (healthy and IBS) and at week 4 (patients only). Stool consistency was determined by the Bristol Stool Form scale. Fecal samples were collected from Cohort A (seven healthy subjects and eight IBS patients), and Cohort B (seven healthy subjects and 11 IBS patients). The fecal metabolome of IBS patients was stable short-term (Cohort A, 5 days and within the same day) and long-term (Cohort B, 4 weeks). A similar trend was observed over 5 days in the healthy subjects of Cohort A. The metabolome dissimilarity was larger between than within participants over time in both healthy subjects and IBS patients. Further analyses showed that patients had greater range of stool forms (types) than healthy subjects, with no apparent influence on metabolomic dynamics. The fecal metabolome is stable over time within IBS patients as well as healthy subjects. This supports the concept of a stable fecal metabolome in IBS despite fluctuations in stool consistency, and the use of single timepoint sampling to further explore how the fecal metabolome is related to IBS pathogenesis.

Integrated omics analysis reveals the alteration of gut microbiota and fecal metabolites in Cervus elaphus kansuensis

The gut microbiota is the largest and most complex microecosystem in animals. It is influenced by the host’s dietary habits and living environment, and its composition and diversity play irreplaceable roles in animal nutrient metabolism, immunity, and adaptation to the environment. Although the gut microbiota of red deer has been studied, the composition and function of the gut microbiota in Gansu red deer (Cervus elaphus kansuensis), an endemic subspecies of red deer in China, has not been reported. In this study, the composition and diversity of the gut microbiome and fecal metabolomics of C. elaphus kansuensis were identified and compared for the first time by using 16S rDNA sequencing, metagenomic sequencing, and LC-MS/MS. There were significant differences in gut microbiota structure and diversity between wild and farmed C. elaphus kansuensis. The 16S rDNA sequencing results showed that the genus UCRD-005 was dominant in both captive red deer (CRD) and wild red deer (WRD). Metagenomic sequencing showed similar results to those of 16S rDNA sequencing for gut microbiota in CRD and WRD at the phylum and genus levels. 16S rDNA and metagenomics sequencing data suggested that Bacteroides and Bacillus might serve as marker genera for CRD and WRD, respectively. Fecal metabolomics results showed that 520 metabolites with significant differences were detected between CRD and WRD and most differential metabolites were involved in lipid metabolism. The results suggested that large differences in gut microbiota composition and fecal metabolites between CRD and WRD, indicating that different dietary habits and living environments over time have led to the development of stable gut microbiome characteristics for CRD and WRD to meet their respective survival and reproduction needs.Key points• Environment and food affected the gut microbiota and fecal metabolites in red deer• Genera Bacteroides and Bacillus may play important roles in CRD and WRD, respectively• Flavonoids and ascorbic acid in fecal metabolites may influence health of red deer

Non-targeted metabolomics strategy reveals the role of Geng-Nian-Shu in regulating ferroptosis in perimenopausal syndrome

Ovariectomy (OVX) is usually accompanied by the occurrence of metabolic syndrome. Previous studies have shown that Geng-Nian-Shu (GNS) plays an important regulatory role in perimenopausal syndrome (PMS) rats. GNS is a traditional Chinese medicine (TCM) prescription which composed of Suanzaoren Decoction and Ganmai Dazao Decoction in "Jingui Yaolue" and Siwu Decoction in "Heji Jufang". Recently, metabolomics analysis has been used to identify slight changes in the metabolic profile and to help understand disease progression and therapeutic interventions in PMS. However, the mechanism of GNS in the treatment of PMS is still unknown. We purposed to study the metabolic characteristics of PMS by serum and fecal metabolomics, and revealed the internal mechanism of GNS regulating ferroptosis against PMS. The PMS model was established by surgical removal of 4/5 ovaries of rats. HPLC-Q-TOF/MS was used to analyze the metabolomics of rat plasma and feces to explore the potential mechanism of GNS in PMS. The expression of ferroptosis-related proteins in rat ovaries was detected by tissue Prussian blue staining, Elisa kit and Western blotting. Cluster analysis of differential metabolites in plasma and feces between the control group and the model group showed that organic acids and their derivatives, lipids and lipid molecules were mainly disturbed during PMS in rats. After GNS administration, 17 differential metabolites were adjusted, involving several major pathways, such as the tricarboxylic acid (TCA) cycle, biosynthesis of amino acids and biosynthesis of unsaturated fatty acids. Further, we found that GNS affected ferroptosis in ovarian cells by regulating endogenous substances in OVX rats. Our study provides new insights into the mechanism of OVX-induced metabolic syndrome based on non-targeted metabolomics. It provides new ideas for the development and application of GNS and the diagnosis and treatment of PMS.

Utilizing NMR fecal metabolomics as a novel technique for detecting the physiological effects of food shortages in waterfowl.

Metabolomics is the study of small, endogenous metabolites that participate in metabolic reactions, including responses to stressors. Anthropogenic and environmental changes that alter habitat and food supply can act as stressors in wild waterfowl. These alterations invoke a series of physiological processes to provide energy to restore homeostasis and increase survival. In this study, we utilized fecal metabolomics to measure metabolites and identify pathways related to a 6-day feed restriction in captive mallard ducks (Anas platyrhynchos, n = 9). Fecal samples were collected before (baseline) and during feed restriction (treatment). H1 Nuclear Magnetic Resonance (NMR) spectroscopy was performed to identify metabolites. We found that fecal metabolite profiles could be used to distinguish between the feed-restricted and baseline samples. We identified metabolites related to pathways for energy production and metabolism endpoints, and metabolites indicative of gut microbiota changes. We also demonstrated that mallard ducks could utilize endogenous reserves in times of limited caloric intake. Fecal metabolomics shows promise as a non-invasive novel tool in identifying and characterizing physiological responses associated with stressors in a captive wild bird species.

Early-life antibiotic exposure promotes house dust mite-induced allergic airway inflammation by impacting gut microbiota and lung lipid metabolism

Asthma is a chronic inflammatory respiratory disease. Early-life antibiotic exposure is a unique risk factor for the incidence and severity of asthma later in life. Perturbations in microbial–metabolite–immune interaction caused by antibiotics are closely associated with the pathogenesis of allergy and asthma. We investigated the effect of early intervention with common oral antibiotics on later asthma exacerbations and found that different antibiotic exposures can amplify different types of immune responses induced by HDM. Cefixime (CFX) promoted a biased type 2 inflammation, azithromycin (AZM) enhanced Th17 immune response, and cefuroxime axetil (CFA) induced eosinophils recruitment. Moreover, early-life antibiotic exposure can have short- and long-term effects on the abundance, composition, and diversity of the gut microbiota. In the model of CFX-promoted type 2 airway inflammation, fecal metabolomics indicated abnormal lipid metabolism and T cell response. Lipidomic also suggested allergic airway inflammation amplified by CFX is closely associated with abnormal lipid metabolism in lung tissues. Moreover, abnormalities in lipid metabolism–related genes (LMRGs) were found to have cellular heterogeneity be associated with asthma severity by bioinformatics analysis.

Analysis of fecal microbiome and metabolome changes in goats with pregnant toxemia

BackgroundPregnancy toxemia is a common disease, which occurs in older does that are pregnant with multiple lambs in the third trimester. Most of the sick goats die within a few days, which can seriously impact the economic benefits of goat breeding enterprises. The disease is believed to be caused by malnutrition, stress, and other factors, that lead to the disorder of lipid metabolism, resulting in increased ketone content, ketosis, ketonuria, and neurological symptoms. However, the changes in gut microbes and their metabolism in this disease are still unclear. The objective of this experiment was to evaluate the effect of toxemia of pregnancy on the fecal microbiome and metabolomics of does.ResultsEight pregnant does suspected of having toxemia of pregnancy (PT group) and eight healthy does during the same pregnancy (NC group) were selected. Clinical symptoms and pathological changes at necropsy were observed, and liver tissue samples were collected for pathological sections. Jugular venous blood was collected before morning feeding to detect biochemical indexes. Autopsy revealed that the liver of the pregnancy toxemia goat was enlarged and earthy yellow, and the biochemical results showed that the serum levels of aspartate aminotransferase (AST) and β-hydroxybutyric acid (B-HB) in the PT group were significantly increased, while calcium (Ca) levels were significantly reduced. Sections showed extensive vacuoles in liver tissue sections. The microbiome analysis found that the richness and diversity of the PT microbiota were significantly reduced. Metabolomic analysis showed that 125 differential metabolites were screened in positive ion mode and enriched in 12 metabolic pathways. In negative ion mode, 100 differential metabolites were screened and enriched in 7 metabolic pathways.ConclusionsEvidence has shown that the occurrence of pregnancy toxemia is related to gut microbiota, and further studies are needed to investigate its pathogenesis and provide research basis for future preventive measures of this disease.

Musculus senhousei peptides alleviated alcoholic liver injury via the gut-liver axis.

Alcoholic liver injury has become a leading threat to human health, with complicated pathogenesis and limited therapeutic options. Our previous study showed that Musculus senhousei peptides (MSPs) exhibit protective potential against early-stage alcoholic liver injury, although the underlying mechanism is not yet clear. In this study, histopathological analysis, mRNA abundance of injury-associated biomarkers, the gut microbiota, and faecal metabolome were evaluated using a mouse model subjected to acute alcohol exposure, aiming to identify the mechanism by which MSP can alleviate alcoholic hepatotoxicity. The results showed that MSP intervention significantly ameliorated symptoms of liver injury (suppressed serum ALT increment, hepatic lipid accumulation, and neutrophil infiltration in liver tissue), and reversed the abnormal mRNA abundance of biomarkers associated with oxidative stress (iNOS), inflammation (TNF-α, IL-1β, MCP-1, TNF-R1, and TLR4), and apoptosis (Bax and Casp. 3) in the liver. Moreover, MSP improved intestinal barrier function by increasing the expression of tight junction proteins (Claudin-1 and Claudin-3). Further analysis of faecal microbiota and metabolome revealed that MSP promoted the growth of tryptophan-metabolizing bacteria (Clostridiales, Alistipes, and Odoribacter), leading to increased production of indole derivatives (indole-3-lactic acid and N-acetyltryptophan). These results suggested that MSPs may alleviate alcohol-induced liver injury targeting the gut-liver axis, and could be an effective option for the prevention of alcoholic liver injury.

Glucosinolate extract from radish (Raphanus sativus L.) seed attenuates high-fat diet-induced obesity: insights into gut microbiota and fecal metabolites.

Radish seed is a functional food with many beneficial health effects. Glucosinolates are characteristic components in radish seed that can be transformed into bioactive isothiocyanates by gut microbiota. The present study aims to assess anti-obesity efficacy of radish seed glucosinolates (RSGs) and explored the underlying mechanisms with a focus on gut microbiota and fecal metabolome. High-fat diet-induced obese mice were supplemented with different doses of RSGs extract for 8 weeks. Changes in body weight, serum lipid, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels; and pathological changes in the liver and adipose tissue were examined. Fecal metabolome and 16S rRNA gene sequencing were used to analyze alterations in fecal metabolite abundance and the gut microbiota, respectively. Results showed that RSG extract prevented weight gain and decreased serum lipid, ALT, AST levels and lipid deposition in liver and epididymal adipocytes in obese mice. Treatment with RSG extract also increased gut microbiota diversity and altered the dominant bacteria genera in the gut microbiota, decreasing the abundance of Faecalibaculum and increasing the abundance of Allobaculum, Romboutsia, Turicibacter, and Akkermansia. Fecal metabolome results identified 570 differentially abundant metabolites, of which glucosinolate degradation products, such as sulforaphene and 7-methylsulfinylheptyl isothiocyanate, were significantly upregulated after RSG extract intervention. Furthermore, enrichment analysis of metabolic pathways showed that the anti-obesity effects of RSG extract may be mediated by alterations in bile secretion, fat digestion and absorption, and biosynthesis of plant secondary metabolites. Overall, RSG extract can inhibit the development of obesity, and the obesity-alleviating effects of RSG are related to alternative regulation of the gut microbiota and glucosinolate metabolites.

Microbial Ecology and Metabolism of Emerging Adulthood: Gut Microbiome Insights from a College Freshman Cohort.

The human gut microbiome (GM) undergoes dynamic changes throughout life, transitioning from infancy to adulthood. Despite improved understanding over the past years about how genetics, lifestyle, and the external environment impact the GM, limited research has explored the GM's evolution during late-stage adolescence, especially among college students. This study addresses this gap by investigating the longitudinal dynamics of fecal microbial, functional, and metabolomic signatures in a diverse group of first-year, dormitory-housed college students. A total of 485 stool samples from 246 participants were analyzed, identifying four primary GM community types, predominantly led by Bacteroides (66.8% of samples), as well as Blautia and Prevotella. The Prevotella/Bacteroides (P/B) ratio emerged as a robust GM composition indicator, predictively associated with 15 metabolites. Notably, higher P/B ratios correlated negatively with p-cresol sulfate and cholesterol sulfate, implying potential health implications, while positively correlating with kynurenic acid. Distinct GM transition and stability patterns were found from a detailed longitudinal subset of 93 participants over an academic year. Parasutterella and the Ruminococcus gnavus group exhibited positive associations with compositional variability, whereas Faecalibacterium and Eubacterium ventriosum group displayed negative associations, the latter suggesting stabilizing roles in the GM. Most notably, nearly half of the longitudinal cohort experienced GM community shifts, emphasizing long-term GM adaptability. Comparing individuals with stable community types to those undergoing transitions, we observed significant differences in microbial composition and diversity, signifying substantial shifts in the microbiota during transitions. Although diet-related variables contributed to some observed variance, diet did not independently predict the probability of switching between community types within the study's timeframe via multi-state Markov modeling. Furthermore, exploration of stability within dynamic microbiomes among the longitudinal cohort experiencing shifts in community types revealed that microbiome taxa at the genus level exhibited significantly higher total variance than estimated functional and fecal metabolomic features. This suggests tight control of function and metabolism, despite community shifting. Overall, this study highlights the dynamic nature of the late-stage adolescent GM, the role of core taxa, metabolic pathways, the fecal metabolome, and lifestyle and dietary factors, contributing to our understanding of GM assembly and potential health implications during this life phase.

The Beneficial Effects of Dietary Astragali Radix Are Related to the Regulation of Gut Microbiota and Its Metabolites.

Astragali Radix (AR) or its extract has been used as an herbal medicine and dietary supplement in China, Europe, and the United States. The gut microbiota could provide new insights for exploring dietary supplements' underlying mechanism on organisms. However, no reports have focused on the regulatory effect of AR on the gut microbiota as a dietary supplement. In this study, healthy ICR mice of either sex were divided into AR and control (CON) groups and given AR water extract (4.55 mg/kg·day-1) or saline by gavage for 14 days, respectively. Then 16S rRNA gene sequencing and ultra-high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry-based fecal metabolomics were integrated to investigate the benefits of dietary AR. Weighted gene coexpression network analysis was also introduced to investigate the metabolites with highly synergistic changes. AR supplementation influenced the structure of intestinal microflora, especially enriching short-chain fatty acid-producing bacteria g_Coprobacillus, g_Prevotella, and g_Parabacteroides. AR also significantly altered the fecal metabolome, mainly related to amino acid metabolism, nucleotide metabolism, and bile acid (BA) metabolism. Moreover, the increased secondary BAs and BA-sulfates might closely relate to intestinal microflora. These findings provide valuable insights for future research of dietary AR as a functional food.

To explore the mechanism of acupoint application in the treatment of primary dysmenorrhea by 16S rDNA sequencing and metabolomics.

Graphene-based warm uterus acupoint paste (GWUAP) is an emerging non-drug alternative therapy for the treatment of primary dysmenorrhea (PD), but the underlying mechanism is still unclear. SD female rats were randomly divided into control group, model group and treatment group to explore the mechanism of GWUAP in the treatment of PD. Combined with 16S rDNA and fecal metabolomics, the diversity of microbiota and metabolites in each group was comprehensively evaluated. In this study, GWUAP reduced the torsion score of PD model rats, improved the pathological morphology of uterine tissue, reduced the pathological damage score of uterine tissue, and reversed the expression levels of inflammatory factors, pain factors and sex hormones. The 16 S rDNA sequencing of fecal samples showed that the abundance of Lactobacillus in the intestinal flora of the model group decreased and the abundance of Romboutsia increased, while the abundance of Lactobacillus in the intestinal flora of the treatment group increased and the abundance of Romboutsia decreased, which improved the imbalance of flora diversity in PD rats. In addition, 32 metabolites related to therapeutic effects were identified by metabolomics of fecal samples. Moreover, there is a close correlation between fecal microbiota and metabolites. Therefore, the mechanism of GWUAP in the treatment of PD remains to be further studied.

Fecal microbiota composition, serum metabolomics, and markers of inflammation in dogs fed a raw meat-based diet compared to those on a kibble diet.

Despite the potential health risks associated with feeding raw and non-traditional diets, the use of these diets in dogs is increasing, yet the health outcomes associated with these diets is not well understood. This study investigates the effect of feeding dogs a kibble or raw meat-based diets on fecal microbiota composition, serum metabolomics and inflammatory markers. Clinically healthy dogs with a history of consuming either kibble (KD, n = 27) or raw meat-based diets (RMBD, n = 28) for more than 1 year were enrolled. Dogs were fed a standardized diet of either a single brand of KD or RMBD for 28 days. Serum and fecal samples were collected for analysis of microbiota, metabolomics, and inflammatory markers. Multiple regression analysis was performed for each of the metabolites and inflammatory markers, with feed group, age and BCS included as independent variables. The fecal microbiota composition differed between the KD and RMBD groups. Beta-diversity and some indices of alpha-diversity (i.e., Shannon and Simpson) were different between the two diet groups. Sixty- three serum metabolites differed between KD and RMBD-fed dogs with the majority reflecting the differences in macronutrient composition of the two diets.Fecal IAP, IgG and IgA were significantly higher in RMBD dogs compared to KD dogs, while systemic markers of inflammation, including serum c-reactive protein (CRP), galectin, secretory receptor of advanced glycation end-products (sRAGE), haptoglobin, and serum IgG were similar in dogs fed either diet. Diet composition significantly affected fecal microbiota composition and metabolome. Although it had a potentially beneficial effect on local inflammatory markers, feeding RMBD had no impact on systemic inflammation. The influence of these changes on long term health outcomes provides an area for future study.

Comprehensive fecal metabolomics and gut microbiota study of the protective mechanism of herbal pair Polygonum hydropiper-Coptis chinensis in rats with stress-induced gastric mucosal damage.

Introduction: Stress-related gastric mucosal lesions (SGMLs) are the most common complication in critical care patients. Previous studies have demonstrated that herbal pair (HP), Polygonum hydropiper-Coptis chinensis (HP P-C) has the anti-SGML effect. However, the underlying mechanism of HP P-C against SGML remains elusive. This study aimed to elucidate how HP P-C extracts exert their protective effects on SGML by examining the role of gut microbiota and metabolites. Methods: SD rats were pretreated with different doses of HP P-C extracts for 6 days, followed by inducing SGML with water-immersion restraint stress (WIRS). After a comprehensive evaluation of serum and gastric tissue indicators in rats, 16S rRNA sequencing and metabolomics analyses were conducted to assess the impact of HP P-C on the fecal microorganisms and metabolites and their correlation. Results: Animal experiment suggested that pretreatment with HP P-C effectively reduced the gastric mucosal lesions, remarkably increased superoxide dismutase (SOD) activity in SGML model rats induced by WIRS. 16S rRNA sequencing analysis showed that HP P-C altered the composition of gut microbiota by raising the abundance of Lactobacillus and Akkermansia. In addition, metabolomics data identified seventeen main differential metabolites related to WIRS-induced gastric mucosal injury, primarily involving in tyrosine metabolism and betalain biosynthesis. HP P-C was found to regulate tyrosine metabolism and betalain biosynthesis by down-regulating the tyramine, L-tyrosine and L-dopa and up -regulating the gentisic acid and dopaquinone. Conclusion: Taken together, this study indicated that HP P-C could effectively protect against WIRS-induced gastric mucosal lesions by modulating intestinal flora and metabolites.

Gut microbiota-bile acid axis mediated the beneficial associations between dietary lignans and hyperuricemia: a prospective study.

Background: The escalating prevalence of hyperuricemia is emerging as a significant public health concern. The association between dietary lignans and hyperuricemia is yet to be fully elucidated. Our study aims to evaluate the relationships between dietary lignan intake and hyperuricemia among middle-aged and elderly Chinese individuals, with an additional focus on investigating the underlying mechanisms. Methods: Dietary lignan intake was measured using a validated Food Frequency Questionnaire in 3801 participants at the baseline. Among them, 2552 participants were included in the longitudinal study with a median follow-up of 10.5 years. The gut microbiota was analyzed by shotgun metagenome sequencing in 1789 participants, and the targeted fecal metabolome was determined in 987 participants using UPLC-MS/MS at the midpoint of follow-up. Results: The multivariable-adjusted HRs (95% CIs) for hyperuricemia incidence in the highest quartile (vs. the lowest quartile) of dietary intake of total lignans, matairesinol, pinoresinol, and secoisolariciresinol were 0.93 (0.78-1.10), 0.77 (0.66-0.90), 0.83 (0.70-0.97), and 0.85 (0.73-1.00), respectively. The gut microbial and fecal metabolic compositions were significantly different across the dietary lignan groups and the hyperuricemia groups. The beneficial associations between dietary lignans and hyperuricemia might be mediated by several gut microbes (e.g., Fusobacterium mortiferum and Blautia sp. CAG-257) and the downstream bile acid products (e.g., NorCA, glycochenodeoxycholic acid, and glycoursodeoxycholic acid). Conclusion: We found that dietary lignans were inversely associated with hyperuricemia incidence, and the gut microbiota-bile acid axis might mediate this association. Our findings provide new perspectives on precise therapeutic targets and underlying mechanisms for conditions associated with elevated uric acid.

Effects of X-ray cranial irradiation on metabolomics and intestinal flora in mice

Cranial radiotherapy is an important treatment for intracranial and head and neck tumors. To investigate the effects of cranial irradiation (C-irradiation) on gut microbiota and metabolomic profile, the feces, plasma and cerebral cortex were isolated after exposing mice to cranial X-ray irradiation at a dose rate of 2.33 Gy/min (5 Gy/d for 4 d consecutively). The gut microorganisms and metabolites were detected by 16 S rRNA gene sequencing method and LC-MS method, respectively. We found that compared with sham group, the gut microbiota composition changed at 2 W and 4 W after C-irradiation at the genus level. The fecal metabolomics showed that compared with Sham group, 44 and 66 differential metabolites were found to be annotated into metabolism pathways at 2 W and 4 W after C-irradiation, which were significantly enriched in the arginine and proline metabolism. Metabolome analysis of serum and cerebral cortex showed that, at 4 W after C-irradiation, the expression pattern of metabolites in serum samples of mice was similar to that of sham group, and the cerebral cortex metabolites of the two groups were completely separated. KEGG functional analysis showed that serum and brain tissue differential metabolites were respectively enriched in tryptophan metabolism, and arginine proline metabolism. The correlation analysis showed that the changes of gut microbiota genera were significantly correlated with the changes of metabolism, especially Helicobacter, which was significantly correlated with many different metabolites at 4 W after C-irradiation. These data suggested that C-irradiation could affect the gut microbiota and metabolism profile, even at relatively long times after C-irradiation.

Aqueous extract of fermented Eucommia ulmoides leaves alleviates hyperlipidemia by maintaining gut homeostasis and modulating metabolism in high-fat diet fed rats

BackgroundAs a traditional Chinese medicinal herb, the lipid-lowing biological potential of Eucommia ulmoides leaves (EL) has been demonstrated. After fermentation, the EL have been made into various products with lipid-lowering effects and antioxidant activity. However, the anti-hyperlipidemic mechanism of fermented Eucommia ulmoides leaves (FEL) is unclear now. PurposeTo evaluate the effects of FEL on hyperlipidemia and investigate the mechanism based on regulating gut homeostasis and host metabolism. MethodsHyperlipidemia animal model in Wistar rats was established after 8 weeks high-fat diet (HFD) fed. The administered doses of aqueous extract of FEL (FELE) were 128, 256 and 512 mg/kg/d, respectively. Serum biochemical parameters detection, histopathological sections analysis, 16S rDNA sequencing of gut microbiota and untargeted fecal metabolomics analysis, were performed to determine the therapeutic effects and predict related pathways of FELE on hyperlipidemia. The changes of proteins and genes elated to lipid were detected by Immunofluorescence (IF) and quantitative real-time polymerase chain reaction (qRT-PCR). Results56 Components in FELE were identified by UPLC-MS, with organic acids, flavonoids and phenolic acids accounting for the majority. The intervention of FELE significantly reduced the body weight, lipid accumulation and the levels of total cholesterol (TC), triglycerides (TG), and low-density lipoprotein-cholesterol (LDL-C) in hyperlipidemia rats, while increased the level of High-density lipoprotein-cholesterol (HDL-C). Meanwhile, FELE improved the inflammatory makers and oxidative stress factors, which is tumor necrosis factor-α (TNF-α), monocyte chemotactic protein-1 (MCP-1), interleukin-6 (IL-6), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT). These results demonstrated that FETE can effectively reduce blood lipids and alleviate inflammation and oxidative damage caused by hyperlipidemia. Mechanistically, FELE restore the homeostasis of gut microbiota by reducing the Firmicutes/Bacteroidetes ratio and increasing the abundance of probiotics, especially Lactobacillus, Rombousia, Bacteroides, Roseburia, Clostridia_UCG-014_Unclassified, while modulated metabolism through amino acid, bile acid and lipid-related metabolism pathways. In addition, the Pearson correlation analysis found that the upregulated bilirubin, threonine, dopamine and downregulated lipocholic acid, d-sphingosine were key metabolites after FELE intervention. IF and qRT-PCR analysis showed that FELE upregulated the expression of fatty acid oxidation proteins and genes (PPARα, CPT1A), bile acid synthesis and excretion proteins and genes (LXRα, CYP7A1, FXR), and downregulated the expression of adipogenic gene (SREBP-1c) by regulating gut microbiota to improve metabolism and exert a lipid-lowering effect. ConclusionThis work filled the lipid-lowering mechanism gap of FEL. FELE can improve HFD-induced hyperlipidemia by regulating the gut microbiota homeostasis and metabolism. Thus, FEL has the potential to develop into the novel raw material of lipid-lowering drugs.

Enteric α-Defensin Contributes to Recovery of Radiation-Induced Intestinal Injury by Modulating Gut Microbiota and Fecal Metabolites.

The effect of ionizing radiation on the gastrointestinal tract is a common complication of abdominal and pelvic radiotherapy. However, the pathological features of radiation enteropathy and its effective medical intervention regimen is still a global challenge. Here, we explored the role and mechanism of enteric alpha-defensins (EαDs) in protecting against radiation enteropathy. To address this, we utilized EαDs-deficiency mice, in which the matrix metallopeptidase 7 to activate Paneth cell α-defensins was knockout (KO) mice, and the complementary wild-type (WT) control mice for this study. Remarkably, the KO mice were more susceptible to 5.0 Gy total-body irradiation, resulting in worse clinic scores and lower survival rate, compared with the wild-type mice. Histological examination indicated that the KO mice were subjected to slow recovery of intestinal villus and mucosa function, characterized by the reduced expression of TFF3, Glut1 and Muc2. In addition, compared with the wild-type controls, the KO mice experienced serious inflammation response in intestinal tissue, indicated by the remarkably increased expression level of IL-1β, IL-6 and IL-12. Using high-throughput sequencing analysis, we found that the intestinal bacterial community of the KO mice was more prone to dysbiosis than that of the WT mice, with significantly increased abundance of opportunistic pathogenic bacteria, such as Streptococcus sp. and Escherichia-Shigella sp., whereas remarkably decreased probiotics harboring Lactobacillus sp., Desulfovibrio sp. etc. Fecal metabolomics analysis indicated that the relative abundance of 31 metabolites arose significantly different between WT and KO mice on day 10 after radiation exposure. A subset of differential metabolites to regulate host metabolism and immunity, such as acetic acid, acetate, butanoic acid, was negatively correlated with the alteration of gut microbiota in the irradiated KO mice. This study provides new insight into EαDs contribution to the recovery of radiation-induced intestinal damage, and suggests a potential novel target to prevent the adverse effects of radiotherapy.

Gut microbiota affects the estrus return of sows by regulating the metabolism of sex steroid hormones

BackgroundSex hormones play important roles in the estrus return of post-weaning sows. Previous studies have demonstrated a complex and bi-directional regulation between sex hormones and gut microbiota. However, the extent to which the gut microbiota affects estrus return of post-weaning sows is largely unknown.ResultsIn this study, we first screened 207 fecal samples from well-phenotyped sows by 16S rRNA gene sequencing and identified significant associations between microbes and estrus return of post-weaning sows. Using metagenomic sequencing data from 85 fecal samples, we identified 37 bacterial species that were significantly associated with estrus return. Normally returning sows were characterized by increased abundances of L. reuteri and P. copri and decreased abundances of B. fragilis, S. suis, and B. pseudolongum. The changes in gut microbial composition significantly altered the functional capacity of steroid hormone biosynthesis in the gut microbiome. The results were confirmed in a validation cohort. Significant changes in sex steroid hormones and related compounds were found between normal and non-return sows via metabolome analysis. An integrated analysis of differential bacterial species, metagenome, and fecal metabolome provided evidence that normal return-associated bacterial species L. reuteri and Prevotella spp. participated in the degradation of pregnenolone, progesterone, and testosterone, thereby promoting estrogen biosynthesis. Furthermore, the microbial metabolites related to sow energy and nutrient supply or metabolic disorders also showed relationships with sow estrus return.ConclusionsAn integrated analysis of differentially abundant bacterial species, metagenome, and fecal metabolome revealed the involvement of L. reuteri and Prevotella spp. in sow estrus return. These findings provide deep insight into the role of gut microbiota in the estrus return of post-weaning sows and the complex cross-talk between gut microbiota and sex hormones, suggesting that the manipulation of the gut microbiota could be an effective strategy to improve sow estrus return after weaning.