Gut microbiota remodeling improves natural aging-related disorders through Akkermansia muciniphila and its derived acetic acid.

Accumulating evidence indicates gut microbiota contributes to aging-related disorders. However, the exact mechanism underlying gut dysbiosis-related pathophysiological changes during aging remains largely unclear. In the current study, we first performed gut microbiota remodeling on old mice by fecal microbiota transplantation (FMT) from young mice, and then characterized the bacteria signature that was specifically altered by FMT. Our results revealed that FMT significantly improved natural aging-related systemic disorders, particularly exerted hepatoprotective effects, and improved glucose sensitivity, hepatosplenomegaly, inflammaging, antioxidative capacity and intestinal barrier. Moreover, FMT particularly increased the abundance of fecal A.muciniphila, which was almost nondetectable in old mice. Interestingly, A.muciniphila supplementation also exerted similar benefits with FMT on old mice. Notably, targeted metabolomics on short chain fatty acids (SCFAs) revealed that only acetic acid was consistently reversed by FMT. Then, acetic acid intervention exerted beneficial actions on both Caenorhabditis elegans and natural aging mice. In conclusion, our current study demonstrated that gut microbiota remodeling improved natural aging-related disorders through A.muciniphila and its derived acetic acid, suggesting that interventions with potent stimulative capacity on A. muciniphila growth and production of acetic acid was alternative and effective way to maintain healthy aging. DATA AVAILABILITY STATEMENT: The data of RNAseq and 16 S rRNA gene sequencing can be accessed in NCBI with the accession number PRJNA848996 and PRJNA849355.

[Comparative study on short and long-term intervention impacts of six Chinese herbs with cold or heat property on lipid and energy metabolism in mice].

This study selected three typical Chinese herbs with cold property(Rhei Radix et Rhizoma, Scutellariae Radix, and Coptidis Rhizoma) and another three with heat property(Cinnamomi Cortex, Zingiberris Rhizoma, and Aconiti Lateralis Radix Praeparata) to observe their regulatory effects on metabolism in animal organism, especially on lipid and energy metabolism in mice after a short-(7 d) and long-term(35 d) intervention. The mRNA expression levels of lipid metabolism genes in epididymal adipose tissue and liver were determined by real-time PCR. The oxygen consumption, carbon dioxide production, and energy consumption were detected by metabolic system. After the short-term intervention, the Chinese herbs with heat property significantly reduced epididymal adipose tissue index and elevated the expression levels of acetyl-CoA carboxylase(ACC), lipoprotein lipase(LPL), and carnitine-palmityl transferase 1(CPT-1) in liver and epididymal adipose tissues. However, those with cold property promoted the expression of above-mentioned genes in epididymal adipose tissue. After the long-term intervention, cold and heat Chinese herbs had no significant effect on epididymal adipose tissue index of animals, while cold Chinese herbs could increase carbon dioxide production and energy consumption and reduce activity. These findings demonstrated that the short-term intervention effects of cold and heat Chinese herbs on animal metabolism were significantly stronger than the long-term intervention effects. Specifically, the short-term intervention with cold Chinese herbs enhanced the lipid metabolism in epididymal adipose tissue, while the heat Chinese herbs promoted lipid metabolism in epididymal adipose tissue and liver. The long-term intervention with cold and heat Chinese herbs resulted in no obvious change in lipid level, but long-term intervention with cold Chinese herbs accelerated energy consumption of the body. This study preliminarily observed the effects of cold and heat Chinese herbs on normal animal physiology from lipid and energy metabolism, which would provide reference for explaining the biological basis of Chinese herbs with cold or heat property based on biological response.

Expert insights: The potential role of the gut microbiome-bile acid-brain axis in the development and progression of Alzheimer's disease and hepatic encephalopathy.

Recent epidemiological and molecular studies have linked the disruption of cholesterol homeostasis to increased risk for developing Alzheimer's disease (AD). Emerging evidence also suggests that brain cholesterol accumulation contributes to the progression of hepatic encephalopathy (HE) via bile acid (BA)-mediated effects on the farnesoid X receptor. In this perspective paper, we reviewed several recently published studies that suggested a role for the gut microbiota transformation of BAs as a factor in AD and HE development/progression. We hypothesize that in addition to cholesterol elimination pathways, alteration of the gut microbiota and subsequent changes in both the serum and brain BA profiles are mechanistically involved in the development of both AD and HE, and thus, are a potential target for the prevention and treatment of the two diseases. Our understanding of the microbiome-BAs-brain axis in central nervous system disease is still evolving, and critical questions regarding the emerging links among central, peripheral, and intestinal metabolic failures contributing to brain health and disease during aging have yet to be addressed.

[Investigation of modulating effect of Qingfei Paidu Decoction on host metabolism and gut microbiome in rats].

This study is to explore the effect of Qingfei Paidu Decoction(QPD) on the host metabolism and gut microbiome of rats with metabolomics and 16 S rDNA sequencing. Based on 16 S rDNA sequencing of gut microbiome and metabolomics(GC-MS and LC-MS/MS), we systematically studied the serum metabolites profile and gut microbiota composition of rats treated with QPD for continued 5 days by oral gavage. A total of 23 and 43 differential metabolites were identified based on QPD with GC-MS and LC-MS/MS, respectively. The involved metabolic pathways of these differential metabolites included glycerophospholipid metabolism, linoleic acid metabolism, TCA cycle and pyruvate metabolism. Meanwhile, we found that QPD significantly regulated the composition of gut microbiota in rats, such as enriched Romboutsia, Turicibacter, and Clostridium_sensu_stricto_1, and decreased norank_f_Lachnospiraceae. Our current study indicated that short-term intervention of QPD could significantly regulate the host metabolism and gut microbiota composition of rats dose-dependently, suggesting that the clinical efficacy of QPD may be related with the regulation on host metabolism and gut microbiome.

Metabolic and Gut Microbial Characterization of Obesity-Prone Mice under a High-Fat Diet.

Obesity is characterized with high heterogeneity due to genetic abnormality, energy imbalance, gut dysbiosis, or a combination of all three. Obesity-prone (OP) and -resistant (OR) phenotypes are frequently observed in rodents, even in those given a high-fat diet (HFD). However, the underlying mechanisms are largely unknown. Male C57BL/6J mice were fed with chow or a HFD for 8 weeks. OP and OR mice were defined based on body weight gain, and integrated serum metabolic and gut microbial profiling was performed by the gas chromatography-mass spectroscopy-based metabolomic sequencing and pyrosequencing of 16S rDNA of cecum contents. A total of 60 differential metabolites were identified in comparisons among Con, OP, and OR groups, in which 27 were OP-related. These differential metabolites are mainly involved in glycolysis, lipids, and amino acids metabolism and the TCA cycle. Meanwhile, OP mice had a distinct profile in gut microbiota compared to those of OR or Con mice, which showed a reduced ratio of Firmicutes to Bacteroidetes and increased Proteobacteria. Moreover, the gut microbial alteration of OP mice was correlated with the changes of the key serum metabolites. OP-enriched Parasutterella from the Proteobacteria phylum correlated to most of metabolites, suggesting that it was essential in obesity. OP mice are distinct in metabolic and gut microbial profiles, and OP-related metabolites and bacteria are of significance for understanding obesity development.

Gut Microbiota Modulation Attenuated the Hypolipidemic Effect of Simvastatin in High-Fat/Cholesterol-Diet Fed Mice.

The hypolipidemic effect of simvastatin varies greatly among patients. In the current study, we investigated the gut microbial-involved mechanisms underlying the different responses to simvastatin. Male C57BL/6J mice were divided into control (Con), high-fat/cholesterol diet (HFD), antibiotic (AB), simvastatin (SV) and antibiotic_simvastatin (AB_SV) groups, respectively. At the end of the experiment, serum samples were collected for lipids and metabolomic analysis, and liver tissues for histology, gene and protein expression analysis. The results showed that antibiotic treatment not only altered the composition of gut microbiota, but attenuated the hypolipidemic effect of SV. A total of 16 differential metabolites between SV and HFD groups were identified with metabolomics, while most of them showed no statistical differences between AB_SV and HFD groups, and similar changes were also observed in bile acids profile. The expressions of several genes and proteins involved in regulating bile acids synthesis were significantly reversed by SV, but not AB_SV in HFD fed mice. In summary, our current study indicated that the hypolipidemic effect of SV was correlated with the composition of the gut microbiota, and the attenuated hypolipidemic effect of SV by gut microbiota modulation was associated with a suppression of bile acids synthesis from cholesterol.

Novel Applications of Metabolomics in Personalized Medicine: A Mini-Review.

Interindividual variability in drug responses and disease susceptibility is common in the clinic. Currently, personalized medicine is highly valued, the idea being to prescribe the right medicine to the right patient. Metabolomics has been increasingly applied in evaluating the therapeutic outcomes of clinical drugs by correlating the baseline metabolic profiles of patients with their responses, i.e., pharmacometabonomics, as well as prediction of disease susceptibility among population in advance, i.e., patient stratification. The accelerated advance in metabolomics technology pinpoints the huge potential of its application in personalized medicine. In current review, we discussed the novel applications of metabolomics with typical examples in evaluating drug therapy and patient stratification, and underlined the potential of metabolomics in personalized medicine in the future.

Gut Microbiota and Nonalcoholic Fatty Liver Disease: Insights on Mechanism and Application of Metabolomics.

Gut microbiota are intricately involved in the development of obesity-related metabolic diseases such as nonalcoholic fatty liver disease (NAFLD), type 2 diabetes, and insulin resistance. In the current review, we discuss the role of gut microbiota in the development of NAFLD by focusing on the mechanisms of gut microbiota-mediated host energy metabolism, insulin resistance, regulation of bile acids and choline metabolism, as well as gut microbiota-targeted therapy. We also discuss the application of a metabolomic approach to characterize gut microbial metabotypes in NAFLD.

ATF4 deficiency protects hepatocytes from oxidative stress via inhibiting CYP2E1 expression.

Activating transcription factor (ATF) 4 is involved in the regulation of oxidative stress in fibroblasts and neurons. The role of ATF4 in hepatocytes, however, is unknown. The aim of this study was to investigate the role of ATF4 in hepatocytes in oxidative stress under a high-fat diet (HFD). Here, we showed that palmitate-stimulated reactive oxygen species (ROS) production and triglyceride (TG) accumulation is blocked by ATF4 deficiency in primary hepatocytes. Consistently, HFD-induced oxidative stress, TG accumulation and expression of cytochrome P450, family 2, subfamily, polypeptide 1 (CYP2E1) are also blocked by knocking down ATF4 expression in the mouse liver. This suggests that ATF4 might regulate oxidative stress via CYP2E1 under an HFD. In addition, we observed that expression of CYP2E1 is indirectly regulated by ATF4 in a cAMP-responsive element binding protein (CREB)-dependent manner, which can directly activate the CYP2E1 promoter activity. Notably, ATF4-stimulated ROS production is inhibited in vivo by treatment with diallyl sulphide, a selective CYP2E1 inhibitor. Finally, we showed that ATF4 expression in the liver is responsible for the protective effects against HFD-induced CYP2E1 expression, oxidative stress, and TG accumulation. Taken together, these observations suggest that ATF4 is a novel regulator of oxidative stress as well as accumulation of TG in response to HFD.

Alteration of bile acid metabolism in the rat induced by chronic ethanol consumption.

Our understanding of the bile acid metabolism is limited by the fact that previous analyses have primarily focused on a selected few circulating bile acids; the bile acid profiles of the liver and gastrointestinal tract pools are rarely investigated. Here, we determined how chronic ethanol consumption altered the bile acids in multiple body compartments (liver, gastrointestinal tract, and serum) of rats. Rats were fed a modified Lieber-DeCarli liquid diet with 38% of calories as ethanol (the amount equivalent of 4-5 drinks in humans). While conjugated bile acids predominated in the liver (98.3%), duodenum (97.8%), and ileum (89.7%), unconjugated bile acids comprised the largest proportion of measured bile acids in serum (81.2%), the cecum (97.7%), and the rectum (97.5%). In particular, taurine-conjugated bile acids were significantly decreased in the liver and gastrointestinal tract of ethanol-treated rats, while unconjugated and glycine-conjugated species increased. Ethanol consumption caused increased expression of genes involved in bile acid biosynthesis, efflux transport, and reduced expression of genes regulating bile acid influx transport in the liver. These results provide an improved understanding of the systemic modulations of bile acid metabolism in mammals through the gut-liver axis.

Astragalus polysaccharides attenuate chemotherapy-induced immune injury by modulating gut microbiota and polyunsaturated fatty acid metabolism.

BACKGROUND: The damage of chemotherapy drugs to immune function and intestinal mucosa is a common side effect during chemotherapy. Astragalus polysaccharides (APS) exhibit immunomodulatory properties and are recognized for preserving the integrity of the human intestinal barrier. Nevertheless, their application and mechanisms of action in chemotherapy-induced immune damage and intestinal barrier disruption remain insufficiently explored. PURPOSE: This study delved into investigating how APS mitigates chemotherapy-induced immune dysfunction and intestinal mucosal injury, while also providing deeper insights into the underlying mechanisms. METHODS: In a chemotherapy mice model induced by 5-fluorouracil (5-Fu), the assessment of APS's efficacy encompassed evaluations of immune organ weight, body weight, colon length, and histopathology. The regulation of different immune cells in spleen was detected by flow cytometry. 16S rRNA gene sequencings, ex vivo microbiome assay, fecal microbiota transplantation (FMT), and targeted metabolomics analysis were applied to explore the mechanisms of APS effected on chemotherapy-induced mice. RESULTS: APS ameliorated chemotherapy-induced damage to immune organs and regulated immune cell differentiation disorders, including CD4+T, CD8+T, CD19+B, F4/80+CD11B+ macrophages. APS also alleviated colon shortening and upregulated the expression of intestinal barrier proteins. Furthermore, APS significantly restored structure of gut microbiota following chemotherapy intervention. Ex vivo microbiome assays further demonstrated the capacity of APS to improve 5-Fu-induced microbiota growth inhibition and compositional change. FMT demonstrated that the regulation of gut microbiota by APS could promote the recovery of immune functions and alleviate shortening of the colon length. Remarkably, APS significantly ameliorated the imbalance of linoleic acid (LA) and α-linolenic acid in polyunsaturated fatty acid (PUFA) metabolism. Further in vitro experiments showed that LA could promote splenic lymphocyte proliferation. In addition, both LA and DGLA down-regulated the secretion of NO and partially up-regulated the percentage of F4/80+CD11B+CD206+ cells. CONCLUSION: APS can effectively ameliorate chemotherapy-induced immune damage and intestinal mucosal disruption by regulating the composition of the gut microbiota and further restoring PUFA metabolism. These findings indicate that APS can serve as an adjuvant to improve the side effects such as intestinal and immune damage caused by chemotherapy.

High Fat Diet and High Sucrose Intake Divergently Induce Dysregulation of Glucose Homeostasis through Distinct Gut Microbiota-Derived Bile Acid Metabolism in Mice.

A high calorie diet such as excessive fat and sucrose intake is always accompanied by impaired glucose homeostasis such as T2DM (type 2 diabetes mellitus). However, it remains unclear how fat and sucrose individually affect host glucose metabolism. In this study, mice were fed with high fat diet (HFD) or 30% sucrose in drinking water (HSD) for 24 weeks, and glucose metabolism, gut microbiota composition, as well as bile acid (BA) profile were investigated. In addition, the functional changes of HFD or HSD-induced gut microbiota were further verified by fecal microbiota transplantation (FMT) and ex vivo culture of gut bacteria with BAs. Our results showed that both HFD and HSD caused dysregulated lipid metabolism, while HFD feeding had a more severe effect on impaired glucose homeostasis, accompanied by reduced hyocholic acid (HCA) levels in all studied tissues. Meanwhile, HFD had a more dramatic influence on composition and function of gut microbiota based on α diversity indices, ß diversity analysis, as well as the abundance of secondary BA producers than HSD. In addition, the phenotypes of impaired glucose homeostasis and less formation of HCA caused by HFD can be transferred to recipient mice by FMT. Ex vivo culture with gut bacteria and BAs revealed HFD-altered gut bacteria produced less HCA than HSD, which might closely associate with reduced relative abundance of C7 epimerase-coding bacteria g_norank/unclassified_f_Eggerthellaceae and bile salt hydrolase-producing bacteria Lactobacillus and Bifidobacterium in HFD group. Our findings revealed that the divergent effects of different high-calorie diets on glucose metabolism may be due to the gut microbiota-mediated generation and metabolism of BAs, highlighting the importance of dietary management in T2DM.

Chrysanthemum morifolium Ramat extract and probiotics combination ameliorates metabolic disorders through regulating gut microbiota and PPARα subcellular localization.

BACKGROUND: Chrysanthemum morifolium Ramat, a traditional Chinese medicine, has the effects on liver clearing, vision improving, and anti-inflammation. C. morifolium and probiotics have been individually studied for their beneficial effects on metabolic diseases. However, the underlying molecular mechanisms were not completely elucidated. This study aims to elucidate the potential molecular mechanisms of C. morifolium and probiotics combination (CP) on alleviating nonalcoholic fatty liver disease (NAFLD) and the dysregulation of glucose metabolism in high-fat diet (HFD)-fed mice. METHODS: The therapeutic effect of CP on metabolism was evaluated by liver histology and serum biochemical analysis, as well as glucose tolerance test. The impact of CP on gut microbiota was analyzed by 16S rRNA sequencing and fecal microbiota transplantation. Hepatic transcriptomic analysis was performed with the key genes and proteins validated by RT-qPCR and western blotting. In addition, whole body Pparα knockout (Pparα-/-) mice were used to confirm the CP-mediated pathway. RESULTS: CP supplementation ameliorated metabolic disorders by reducing body weight and hepatic steatosis, and improving glucose intolerance and insulin resistance in HFD fed mice. CP intervention mitigated the HFD-induced gut microbiota dysbiosis, which contributed at least in part, to the beneficial effect of improving glucose metabolism. In addition, hepatic transcriptomic analysis showed that CP modulated the expression of genes associated with lipid metabolism. CP downregulated the mRNA level of lipid droplet-binding proteins, such as Cidea and Cidec in the liver, leading to more substrates for fatty acid oxidation (FAO). Meanwhile, the expression of CPT1α, the rate-limiting enzyme of FAO, was significantly increased upon CP treatment. Mechanistically, though CP didn't affect the total PPARα level, it promoted the nuclear localization of PPARα, which contributed to the reduced expression of Cidea and Cidec, and increased expression of CPT1α, leading to activated FAO. Moreover, whole body PPARα deficiency abolished the anti-NAFLD effect of CP, suggesting the importance of PPARα in CP-mediated beneficial effect. CONCLUSION: This study revealed the hypoglycemic and hepatoprotective effect of CP by regulating gut microbiota composition and PPARα subcellular localization, highlighting its potential for therapeutic candidate for metabolic disorders.

Shexiang Baoxin Pill enriches Lactobacillus to regulate purine metabolism in patients with stable coronary artery disease.

BACKGROUND: It has been clinically confirmed that the Shexiang Baoxin Pill (SBP) dramatically reduces the frequency of angina in patients with stable coronary artery disease (SCAD). However, potential therapeutic mechanism of SBP has not been fully explored. PURPOSE: The study explored the therapeutic mechanism of SBP in the treatment of SCAD patients. METHODS: We examined the serum metabolic profiles of patients with SCAD following SBP treatment. A rat model of acute myocardial infarction (AMI) was established, and the potential therapeutic mechanism of SBP was explored using metabolomics, transcriptomics, and 16S rRNA sequencing. RESULTS: SBP decreased inosine production and improved purine metabolic disorders in patients with SCAD and in animal models of AMI. Inosine was implicated as a potential biomarker for SBP efficacy. Furthermore, SBP inhibited the expression of genes involved in purine metabolism, which are closely associated with thrombosis, inflammation, and platelet function. The regulation of purine metabolism by SBP was associated with the enrichment of Lactobacillus. Finally, the effects of SBP on inosine production and vascular function could be transmitted through the transplantation of fecal microbiota. CONCLUSION: Our study reveals a novel mechanism by which SBP regulates purine metabolism by enriching Lactobacillus to exert cardioprotective effects in patients with SCAD. The data also provide previously undocumented evidence indicating that inosine is a potential biomarker for evaluating the efficacy of SBP in the treatment of SCAD.

Efficacy and safety of Qushi Huayu, a traditional Chinese medicine, in patients with nonalcoholic fatty liver disease in a randomized controlled trial.

BACKGROUND: The effective treatment of non-alcoholic fatty liver disease (NAFLD) is an unmet medical need. Qushi Huayu (QSHY) is an empirical herbal formula with promising effects in NAFLD rodent models and a connection to gut microbiota regulation. HYPOTHESIS/PURPOSE: This study aimed to evaluate the effects of QSHY in patients with NAFLD through a multicenter, randomized, double-blind, double-dummy clinical trial. STUDY DESIGN: A total of 246 eligible patients with NAFLD and liver dysfunction were evenly divided to receive either QSHY and Dangfei Liganning capsule (DFLG) simulant or QSHY simulant and DFLG (an approved proprietary Chinese medicine for NAFLD in China) for 24 weeks. The primary outcomes were changes in liver fat content, assessed using vibration-controlled transient elastography, and serum alanine aminotransferase (ALT) levels from baseline to Week 24. RESULTS: Both QSHY and DFLG led to reductions in liver fat content and liver enzyme levels post-intervention (p < 0.05). Compared to DFLG, QSHY treatment improved ALT (ß, -0.128 [95 % CI, -0.25, -0.005], p = 0.041), aspartate transaminase (ß, -0.134 [95 % CI, -0.256 to -0.012], p = 0.032), and fibrosis-4 score (ß, -0.129 [95 % CI, -0.254 to -0.003], p = 0.044) levels. QSHY markedly improved gut dysbiosis compared to DFLG, with changes in Escherichia-Shigella and Bacteroides abundance linked to its therapeutic effect on reducing ALT. Patients with a high ALT response after QSHY treatment showed superior reductions in peripheral levels of phenylalanine and tyrosine, along with an elevation in the related microbial metabolite p-Hydroxyphenylacetic acid. CONCLUSION: Our results demonstrate favorable clinical potential for QSHY in the treatment of NAFLD.

Activation of hepatic adenosine A1 receptor ameliorates MASH via inhibiting SREBPs maturation.

Metabolic (dysfunction)-associated steatohepatitis (MASH) is the advanced stage of metabolic (dysfunction)-associated fatty liver disease (MAFLD) lacking approved clinical drugs. Adenosine A1 receptor (A1R), belonging to the G-protein-coupled receptors (GPCRs) superfamily, is mainly distributed in the central nervous system and major peripheral organs with wide-ranging physiological functions; however, the exact role of hepatic A1R in MAFLD remains unclear. Here, we report that liver-specific depletion of A1R aggravates while overexpression attenuates diet-induced metabolic-associated fatty liver (MAFL)/MASH in mice. Mechanistically, activation of hepatic A1R promotes the competitive binding of sterol-regulatory element binding protein (SREBP) cleavage-activating protein (SCAP) to sequestosome 1 (SQSTM1), rather than protein kinase A (PKA) leading to SCAP degradation in lysosomes. Reduced SCAP hinders SREBP1c/2 maturation and thus suppresses de novo lipogenesis and inflammation. Higher hepatic A1R expression is observed in patients with MAFL/MASH and high-fat diet (HFD)-fed mice, which is supposed to be a physiologically adaptive response because A1R agonists attenuate MAFL/MASH in an A1R-dependent manner. These results highlight that hepatic A1R is a potential target for MAFL/MASH therapy.

Toward personalized nutrition: comprehensive phytoprofiling and metabotyping.

Nutrition research is increasingly concerned with the complex interactions between multicomponent dietary ingredients and the human metabolic regulatory system. The substantiation of nutritional health benefits is challenged by the intrinsic complexity of macro- and micronutrients and individualized human metabolic responses. Metabonomics, uniquely suited to assess metabolic responses to deficiencies or excesses of nutrients, is used to characterize the metabolic phenotype of individuals integrating genetic polymorphisms, metabolic interactions with commensal and symbiotic partners such as gut microbiota, as well as environmental and behavioral factors including dietary preferences. The two profiling strategies, metabolic phenotyping (metabotyping) and phytochemical profiling (phytoprofiling), greatly facilitate the measurement of these important health determinants and the discovery of new biomarkers associated with nutritional requirements and specific phytochemical interventions. This paper presents an overview of the applications of these two profiling approaches for personalized nutrition research, with a focus on recent advances in the study of the role of phytochemicals in regulating the human or animal metabolic regulatory system.

Chronic ethanol consumption alters mammalian gastrointestinal content metabolites.

Chronic ethanol consumption is associated with not only the alteration of metabolic profiles in biofluids but also the composition of the gut microbiome. Our understanding of the importance of the intestinal microbiota as well as the disturbances elicited by ethanol intervention is limited by the fact that previous analyses have primarily focused on biofluids and liver tissue metabolome; the metabolic profiles of the gastrointestinal (GI) contents are rarely investigated. In this study, we applied a metabonomics approach using a high performance liquid chromatography-time-of-flight mass spectrometry (HPLC-TOF MS) and gas chromatography-mass spectrometry (GC-MS) to characterize the metabolic alterations of the contents within the GI tract (stomach, duodenum, jejunum, ileum, cecum, colon, and rectum) in male Sprague-Dawley rats following 8 weeks of ethanol exposure. We obtained a snapshot of the distinct changes of the intestinal content metabolite composition in rats with ethanol exposure, which indicated a profound impact of ethanol consumption on the intestinal metabolome. Many metabolic pathways that are critical for host physiology were affected, including markedly altered bile acids, increased fatty acids and steroids, decreased carnitines and metabolites involved in lipid metabolism, a significant decrease of all amino acids and branched chain amino acids, and significantly decreased short chain fatty acids except for acetic acid, which rapidly elevated as a product of ethanol metabolism. These results provide an improved understanding of the systemic alteration of intestinal content metabolites in mammals and the interplay between the host and its complex resident microbiota and may aid in the design of new therapeutic strategies that target these interactions.

Different software processing affects the peak picking and metabolic pathway recognition of metabolomics data.

In untargeted liquid chromatography‒mass spectrometry (LC‒MS) metabolomics studies, data preprocessing and metabolic pathway recognition are crucial for screening important pathways that are disturbed by diseases or restored by drugs. Here, we collected high-resolution mass spectrometry data of serum samples from 221 coronary heart disease (CHD) patients under two different chromatographic columns (BEH amide and C18 column) and evaluated the three commonly used software programs (XCMS, Progenesis QI, MarkerView) from four aspects (including signal drift, peak number, metabolite annotation and metabolic pathway enrichment). The results showed that the data preprocessed by the three software programs have different degrees of signal drift, but the StatTarget could improve the data quality to meet the data analysis requirement after correction. In addition, XCMS surpassed other software in detection of real chromatographic peaks and Progenesis QI was the best performer in terms of the number of metabolite annotation. XCMS and Progenesis QI showed different performance in pathway enrichment. However, metabolic pathways based on the combination of XCMS and Progenesis QI had a high coincidence with Progenesis QI. In addition, we also reported that C18 and amide columns were highly complementary and have great potential for cooperation in the context of metabolic pathways. In this study, the effects of different chromatographic columns and software pretreatments on metabolomics data were evaluated based on clinical large cohort samples, which will provide a reference for the metabolomics of clinical samples and guide subsequent mechanistic research.

Optimizing ex vivo culture conditions to study human gut microbiome.

The inter-individual variations of gut microbiome contribute to the different responses toward drug therapy among populations, developing a reliable ex vivo culture method for mixed bacteria is the urgent need for predicting personal reaction to drug therapy. Unfortunately, very few attentions have been paid to the bias that could be introduced during the culture process for mixed bacteria. Here we systemically evaluated the factors that may affect the outcomes of cultured bacteria from human feces. We demonstrated that inter-individual difference of host gut microbiome was the main factor affecting the outcomes of cultured bacteria, followed by the culture medium and time point. We further optimized a new medium termed GB based on our established multi-dimensional evaluation method, which could mimic the status of in situ host gut microbiome to the highest extent. Finally, we assessed the inter-individual metabolism by host gut microbiome from 10 donors on three frequently used clinical drugs (aspirin, levodopa and doxifluridine) based on the optimized GB medium. Our results revealed obvious variation in drug metabolism by microbiome from different donors, especially levodopa and doxifluridine. This work suggested the optimized culture medium had the potential for exploring the inter-individual impacts of host gut microbiome on drug metabolism.