Metabolomics of repetitive myocardial stunning in chronic multivessel coronary artery stenosis: Effect of non-selective and selective ß1-receptor blockers.

Chronic coronary artery stenosis can lead to regional myocardial dysfunction in the absence of myocardial infarction by repetitive stunning, hibernation or both. The molecular mechanisms underlying repetitive stunning-associated myocardial dysfunction are not clear. We used non-targeted metabolomics to elucidate responses to chronically stunned myocardium in a canine model with and without ß-adrenergic blockade treatment. After development of left ventricular systolic dysfunction induced by ameroid constrictors on the coronary arteries, animals were randomized to 3 months of placebo, metoprolol or carvedilol. We compared these two ß-blockers with their different ß-adrenergic selectivities on myocardial function, perfusion and metabolic pathways involved in tissue undergoing chronic stunning. Control animals underwent sham surgery. Dysfunction in stunned myocardium was associated with reduced fatty acid oxidation and enhanced ketogenic amino acid metabolism, together with alterations in mitochondrial membrane phospholipid composition. These changes were consistent with impaired mitochondrial function and were linked to reduced nitric oxide and peroxisome proliferator-activated receptor signalling, resulting in a decline in adenosine monophosphate-activated protein kinase. Mitochondrial changes were ameliorated by carvedilol more than metoprolol, and improvement was linked to nitric oxide and possibly hydrogen sulphide signalling. In summary, repetitive myocardial stunning commonly seen in chronic multivessel coronary artery disease is associated with adverse metabolic remodelling linked to mitochondrial dysfunction and specific signalling pathways. These changes are reversed by ß-blockers, with the non-selective inhibitor having a more favourable impact. This is the first investigation to demonstrate that ß-blockade-associated improvement of ventricular function in chronic myocardial stunning is associated with restoration of mitochondrial function. KEY POINTS: The mechanisms responsible for the metabolic changes associated with repetitive myocardial stunning seen in chronic multivessel coronary artery disease have not been fully investigated. In a canine model of repetitive myocardial stunning, we showed that carvedilol, a non-selective ß-receptor blocker, ameliorated adverse metabolic remodelling compared to metoprolol, a selective ß1-receptor blocker, by improving nitric oxide synthase and adenosine monophosphate protein kinase function, enhancing calcium/calmodulin-dependent protein kinase, probably increasing hydrogen sulphide, and suppressing cyclic-adenosine monophosphate signalling. Mitochondrial fatty acid oxidation alterations were ameliorated by carvedilol to a larger extent than metoprolol; this improvement was linked to nitric oxide and possibly hydrogen sulphide signalling. Both ß-blockers improved the cardiac energy imbalance by reducing metabolites in ketogenic amino acid and nucleotide metabolism. These results elucidated why metabolic remodelling with carvedilol is preferable to metoprolol when treating chronic ischaemic left ventricular systolic dysfunction caused by repetitive myocardial stunning.

Nitrogen-fixing bacteria promote growth and bioactive components accumulation of Astragalus mongholicus by regulating plant metabolism and rhizosphere microbiota.

BACKGROUND: The excessive application of chemical fertilizers in the cultivation of Astragalus mongholicus Bunge results in a reduction in the quality of the medicinal plant and compromises the sustainable productivity of the soil. PGPB inoculant is a hot topic in ecological agriculture research. In the cultivation of Astragalus mongholicus, the screened nitrogen-fixing bacteria can promote plant growth, however, whether it can promote the accumulation of main bioactive components remains unknown. In this study, mixed inoculants containing 5 strains of growth promoting bacteria (Rhizobium T16 , Sinorhizobium T21 , Bacillus J1 , Bacillus G4 and Arthrobacter J2) were used in the field experiment. The metabolic substances in the root tissues of Astragalus mongholicus were identified during the harvest period by non-targeted metabolomics method, and the differential metabolites between groups were identified by statistical analysis. Meanwhile, high-throughput sequencing was performed to analyze the changes of rhizosphere soil and endophytic microbial community structure after mixed microbial treatment. RESULTS: The results of non-targeted metabolism indicated a significant increase in the levels of 26 metabolites after treatment including 13 flavonoids, 3 saponins and 10 other components. The contents of three plant hormones (abscisic acid, salicylic acid and spermidine) also increased after treatment, which presumed to play an important role in regulating plant growth and metabolism. Studies on endosphere and rhizosphere bacterial communities showed that Rhzobiaceae, Micromonosporaceae, and Hypomicrobiaceae in endophytic, and Oxalobactereae in rhizosphere were significantly increased after treatment. These findings suggest their potential importance in plant growth promotion and secondary metabolism regulation. CONCLUSIONS: This finding provides a basis for developing nitrogen-fixing bacteria fertilizer and improving the ecological planting efficiency of Astragalus mongholicus.

Metabolic profiling of peri-implant crevicular fluid in peri-implantitis.

OBJECTS: This study aims to explore the etiology of peri-implantitis by comparing the metabolic profiles in peri-implant crevicular fluid (PICF) from patients with healthy implants (PH) and those with peri-implantitis (PI). MATERIALS AND METHODS: Fifty-six patients were enrolled in this cross-sectional study. PICF samples were collected and analyzed using both non-targeted and targeted metabolomics approaches. The relationship between metabolites and clinical indices including probing depth (PD), bleeding on probing (BOP), and marginal bone loss (MBL) was examined. Additionally, submucosal microbiota was collected and analyzed using 16S rRNA gene sequencing to elucidate the association between the metabolites and microbial communities. RESULTS: Significant differences in metabolic profiles were observed between the PH and PI groups, with 179 distinct metabolites identified. In the PI group, specific amino acids and fatty acids were significantly elevated compared to the PH group. Organic acids including succinic acid, fructose-6-phosphate, and glucose-6-phosphate were markedly higher in the PI group, showing positive correlations with mean PD, BOP, and MBL. Metabolites that increased in the PI group positively correlated with the presence of Porphyromonas and Treponema and negatively with Streptococcus and Haemophilus. CONCLUSIONS: This study establishes a clear association between metabolic compositions and peri-implant condition, highlighting enhanced metabolite activity in peri-implantitis. These findings open avenues for further research into metabolic mechanisms of peri-implantitis and their potential therapeutic implications.

Exploring the Mechanism of H2S Synthesis in Male Bactrian Camel Poll Glands Based on Data Independent Acquisition Proteomics and Non-Targeted Metabolomics.

During estrus, the poll glands of male Bactrian Camels (Camelus Bactrianus) become slightly raised, exuding a large amount of pale yellow watery secretion with a characteristic odor that may contain hydrogen sulfide (H2S). However, whether H2S can be synthesized in the poll glands of male Bactrian Camels and its role in inducing camel estrus remains unclear. This study aimed to identify differentially expressed proteins (DEPs) and signaling pathways in the poll gland tissues of male Bactrian Camels using data independent acquisition (DIA) proteomics. Additionally, gas chromatography-mass spectrometry (GC-MS) was performed to identify differentially expressed metabolites (DEMs) in the neck hair containing secretions during estrus in male Bactrian Camels, to explore the specific expression patterns and mechanisms in the poll glands of camels during estrus. The results showed that cystathionine-γ-lyase (CTH) and cystathionine-ß-synthase (CBS), which are closely related to H2S synthesis in camel poll glands during estrus, were mainly enriched in glycine, serine, and threonine metabolism, amino acid biosynthesis, and metabolic pathways. In addition, both enzymes were widely distributed and highly expressed in the acinar cells of poll gland tissues in camels during estrus. Meanwhile, the neck hair secretion contains high levels of amino acids, especially glycine, serine, threonine, and cystathionine, which are precursors for H2S biosynthesis. These results demonstrate that the poll glands of male Bactrian Camels can synthesize and secrete H2S during estrus. This study provides a basis for exploring the function and mechanism of H2S in the estrus of Bactrian Camels.

Potential nutritional and functional matters in yeast culture prepared by soybean meal fermentation.

BACKGROUND: Yeast culture (YC) is a product fermented on a specific medium, which is a type of postbiotic of anaerobic solid-state fermentation. Although YC has positive effects on the animal growth and health, it contains a variety of beneficial metabolites as dark matter, which have not been quantified. In the present study, liquid chromatography-tandem mass spectrometry is employed to identify the unknown metabolites. Following their identification, the important chemicals are quantified using HPLC-diode array detection methods. RESULTS: Non-targeted metabolomics studies showed that 670 metabolites in total were identified in YC, of which 23 metabolites significantly increased, including organic acids, amino acids, nucleosides and purines, isoflavones, and other substances. The chemical quantitative analysis showed that the contents of succinic acid, aminobutyric acid, glutamine, purine and daidzein increased by 84.42%, 51.07%, 100%, 68.85% and 4.60%, respectively. CONCLUSION: Therefore, the use of non-targeted metabolomics combined with chemical quantitative analysis to reveal the nutritional and functional substances of YC could help to elucidate the postbiotic mechanism and provide theoretical support for the regulation of the directional accumulation of beneficial metabolites. © 2024 Society of Chemical Industry.

Exploring the flavor changes in mung bean flour through Lactobacillus fermentation: insights from volatile compounds and non-targeted metabolomics analysis.

BACKGROUND: Mung beans are highly nutritious but their leguminous flavor limits their development. Lactic acid bacteria (LAB) fermentation can decrease unwanted bean flavors in legumes and enhance their flavor. This study examined the influence of Lactobacillus fermentation on the flavor characteristics of mung bean flour (MBF) using volatile compounds and non-targeted metabolomics. RESULTS: Lactobacillus plantarum LP90, Lactobacillus casei LC89, and Lactobacillus acidophilus LA85 eliminated 61.37%, 48.29%, and 43.73%, respectively, of the primary bean odor aldehydes from MBF. The relative odor activity value (ROAV) results showed that fermented mung bean flour (FMBF) included volatile chemicals that contributed to fruity, flowery, and milky aromas. These compounds included ethyl acetate, hexyl formate, 3-hydroxy-2-butanone, and 2,3-butanedione. The levels of amino acids with a fresh sweet flavor increased significantly by 93.89, 49.40, and 35.27% in LP90, LC89, and LA85, respectively. A total of 49 up-regulated and 13 down-regulated significantly differential metabolites were annotated, and ten metabolic pathways were screened for contributing to the flavor. The correlation between important volatile compounds and non-volatile substances relies on two primary metabolic pathways: the citric acid cycle pathway and the amino acid metabolic system. CONCLUSION: The flavor of MBF was enhanced strongly by the process of Lactobacillus fermentation, with LP90 having the most notable impact. These results serve as a reference for identifying the flavor of FMBF. © 2024 Society of Chemical Industry.

[Microcirculatory visualization and metabolomics of Dalbergia cochinchinensis in ameliorating coronary microvascular dysfunction in rats].

This study employed microcirculation visualization and metabolomics methods to explore the effect and possible mechanism of Dalbergia cochinchinensis in ameliorating coronary microvascular dysfunction(CMD) induced by microsphere embolization in rats. Sixty SPF-grade male SD rats were randomized into sham, model, and low-, medium-, and high-dose [1.5, 3.0, and 6.0 g·kg~(-1)·d~(-1), respectively] D. cochinchinensis water extract groups. The rats in sham and model groups were administrated with equal volume of normal saline by gavage once a day for 7 consecutive days. The rat model of CMD was prepared by injecting polyethylene microspheres into the left ventricle, while the sham group was injected with an equal amount of normal saline. A blood flow meter was used to measure blood flow, and a blood rheometer to measure blood viscosity and fibrinogen content. An automatic biochemical analyzer and reagent kits were used to measure the serum levels of myocardial enzymes, glucose, and nitric oxide(NO). Hematoxylin-eosin(HE) staining was used to observe the pathological changes of myocardial tissue. DiI C12/C18 perfusion was used to infuse coronary microvessels, and the structural and morphological changes were observed using a confocal laser scanning microscope. AngioTool was used to analyze the vascular area, density, radius, and mean E lacunarity in the microsphere embolization area, and vascular blood flow resistance was calculated based on Poiseuille's law. Non-targeted metabolomics based on high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry(UPLC-Q-TOF-MS) was employed screen potential biomarkers and differential metabolites regulated by D. cochinchinensis and the involved metabolic pathways were enriched. The pharmacodynamic results showed that compared with the model group, D. cochinchinensis significantly increased mean blood flow, reduced plasma fibrinogen content, lowered the levels of myocardial enzymes such as creatine kinase(CK), creatine kinase-MB(CK-MB), and lactate dehydrogenase(LDH), alleviate myocardial injury, and protect damaged myocardium. In addition, D. cochinchinensis significantly increased serum NO content, promoted vascular smooth muscle relaxation, dilated blood vessels, lowered serum glucose(GLU) level, improved myocardial energy metabolism, and alleviated pathological changes in myocardial fibrosis and inflammatory cell infiltration. The results of coronary microcirculation perfusion showed that D. cochinchinensis improved the vascular morphology, increased the vascular area, density, and radius, reduced vascular mean E lacunarity and blood flow resistance, and alleviated vascular endothelial damage in CMD rats. The results of metabolomics identified 45 differential metabolites between sham and model groups, and D. cochinchinensis recovered the levels 25 differential metabolites, which were involved in 8 pathways including arachidonic acid metabolism, arginine biosynthesis, and sphingolipids metabolism. D. cochinchinensis can ameliorate coronary microcirculation dysfunction caused by microsphere embolization in rats, and it may alleviate the pathological changes of CMD rats by regulating inflammatory reaction, endothelial damage, and phospholipid metabolism.

[Non-targeted renal metabolomics reveals multi-target effects of Dahuang Zhechong Pills on renal aging in rats].

This study aims to observe the effects of the traditional Chinese medicine prescription Dahuang Zhechong Pills(DHZCP on renal aging and explore its potential multi-target effects. Rats were assigned into the normal, model, DHZCP, and vitamin E(VE)groups. Firstly, the rat model of D-galactose(D-gal)-induced renal aging was established. During the modeling period, the rats in the 4 groups were administrated with double distilled water, double distilled water, DHZCP suspension, and VE suspension, respectively,by gavage every day. On day 60 of intervention, the indicators of renal aging and injury in rats were measured, including the function,histopathological characteristics, senescence-associated ß-galactosidase( SA-ß-gal) staining, and expression levels of Klotho and proteins associated with cell cycle arrest and senescence-associated secretory phenotype(SASP) in the renal tissue. Moreover, nontargeted metabolomic analysis of the renal tissue was performed for the 4 groups of rats to screen out the potential biomarkers and metabolic pathways. Finally, the signaling pathways of key targets were preliminarily validated. The results showed that DHZCP and VE significantly improved the renal function, histopathological features of renal tubular/interstitial tissue, and degree of SA-ß-gal staining, up-regulated the expression level of Klotho, and down-regulated the expression levels of proteins associated with cell cycle arrest and SASP in the renal tissue of the aging rats. In addition, DHZCP and VE regulated the metabolites in the renal tissue of the aging rats. There were 21 common differential metabolites. Among them, 5 differential metabolites were significantly increased in the aging rats and recovered after DHZCP or VE treatment, and they were involved in the lipid metabolism and energy metabolism pathways. The areas under the curves of the groups in comparison varied within the range of 0. 88-1. DHZCP regulated multiple signaling pathways, such as the adenosine monophosphate-activated protein kinase(AMPK), cyclic guanosine monophosphate-protein kinase G( c GMP-PKG), cyclic adenylic acid( c AMP), phosphatidylinositol-3-kinase-protein kinase B( PI3K-Akt), mammalian target of rapamycin(mTOR), and autophagy signaling pathways. In addition, it affected the multiple metabolic pathways, such as renin secretion, longevity regulation pathway, diabetic cardiomyopathy, and niacin and nicotinamide metabolism. DHZCP and VE significantly up-regulated the expression level of the key proteins in the AMPK signaling pathway in the renal tissue of the aging rats. In all, DHZCP and VE could mitigate renal aging and injury. DHZCP exerted multi-target effects via multiple signaling pathways and metabolic pathways in the kidney, in which the AMPK signaling pathway may be one of the key targets for action.

Urine Metabolites Changes in Acute Myocardial Infarction Rats via Metabolomic Analysis.

OBJECTIVES: To screen biomarkers for forensic identification of acute myocardial infarction (AMI) by non-targeted metabolomic studies on changes of urine metabolites in rats with AMI. METHODS: The rat models of the sham surgery group, AMI group and hyperlipidemia + acute myocardial infarction (HAMI) group were established. Ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS) was used to analyze the changes of urine metabolic spectrometry in AMI rats. Principal component analysis, partial least squares-discriminant analysis, and orthogonal partial least squares-discriminant analysis were used to screen differential metabolites. The MetaboAnalyst database was used to analyze the metabolic pathway enrichment and access the predictive ability of differential metabolites. RESULTS: A total of 40 and 61 differential metabolites associated with AMI and HAMI were screened, respectively. Among them, 22 metabolites were common in both rat models. These small metabolites were mainly concentrated in the niacin and nicotinamide metabolic pathways. Within the 95% confidence interval, the area under the curve (AUC) values of receiver operator characteristic curve for N8-acetylspermidine, 3-methylhistamine, and thymine were greater than 0.95. CONCLUSIONS: N8-acetylspermidine, 3-methylhistamine, and thymine can be used as potential biomarkers for AMI diagnosis, and abnormal metabolism in niacin and nicotinamide may be the main causes of AMI. This study can provide reference for the mechanism and causes of AMI identification.

Enhancement of the organic acid content and antioxidant capacity of yellow whey through fermentation with Lacticaseibacillus casei YQ336.

Fermentation is considered an effective tool for improving the functional characteristics of food. In this study, Lacticaseibacillus casei YQ336 was used to ferment yellow whey, and physical and chemical analysis was performed to identify the changes in the nutritional components and antioxidant activity of the fermented yellow whey. Non-targeted metabolomics was used to study the transformation of small molecular substances in the fermented yellow whey. After 48 h of pure culture fermentation with L. casei YQ336, the pH of yellow whey decreased significantly (p < 0.05). Meanwhile, the content of total acids, organic acids, sugars, total phenols, and total flavonoids and the antioxidant activity showed a significant increase (p < 0.05). A total of 628 differential metabolites were identified between fermented and unfermented yellow whey samples, of which 293 were upregulated and 335 were downregulated. After fermentation, due to the growth and metabolic activity of L. casei YQ336, meaningful metabolites such as homovanillic acid, lactic acid, oxalic acid, L-glutamic acid, and phenylalanine, as well as phenyllactic acid, gallic acid, and genistein were produced. This increased the organic acid content and antioxidant activity of yellow whey. The findings provide a theoretical and practical basis for further research on the bio-functional activity of yellow whey and the recycling and utilization of food by-products.

Screening potential biomarkers associated with insulin resistance in high-fat diet-fed mice by integrating metagenomics and untargeted metabolomics.

Insulin resistance is the primary pathophysiological basis for metabolic syndrome and type 2 diabetes. Gut microbiota and microbiota-derived metabolites are pivotal in insulin resistance. However, identifying the specific microbes and key metabolites with causal roles is a challenging task, and the underlying mechanisms require further exploration. Here, we successfully constructed a model of insulin resistance in mice induced by a high-fat diet (HFD) and screened potential biomarkers associated with insulin resistance by integrating metagenomics and untargeted metabolomics. Our findings showed a significant increase in the abundance of 30 species of Alistipes in HFD mice compared to normal diet (ND) mice, while the abundance of Desulfovibrio and Candidatus Amulumruptor was significantly lower in HFD mice than in ND mice. Non-targeted metabolomics analysis identified 21 insulin resistance-associated metabolites, originating from the microbiota or co-metabolized by both the microbiota and the host. These metabolites were primarily enriched in aromatic amino acid metabolism (tryptophan metabolism, tyrosine metabolism, and phenylalanine metabolism) and arginine biosynthesis. Further analysis revealed a significant association between the three distinct genera and 21 differentiated metabolites in the HFD and ND mice. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of representative genomes from 12 species of the three distinct genera further revealed the functional potential in aromatic amino acid metabolism and arginine biosynthesis. This study lays the groundwork for future investigations into the mechanisms through which the gut microbiota and its metabolites impact insulin resistance. IMPORTANCE: In this study, we aim to identify the microbes and metabolites linked to insulin resistance, some of which have not been previously reported in insulin resistance-related studies. This adds a complementary dimension to existing research. Furthermore, we establish a correlation between alterations in the gut microbiota and metabolite levels. These findings serve as a foundation for identifying the causal bacterial species and metabolites. They also offer insights that guide further exploration into the mechanisms through which these factors influence host insulin resistance.

Selenium-enriched yeast, a selenium supplement, improves the rheological properties and processability of dough: From the view of yeast metabolism and gluten alteration.

This study investigated the effect mechanism of selenium (Se)-enriched yeast on the rheological properties of dough from the perspective of yeast metabolism and gluten alteration. As the yeast Se content increased, the gas production rate of Se-enriched yeast slowed down, and dough viscoelasticity decreased. The maximum creep of Se-enriched dough increased by 29%, while the final creep increased by 54%, resulting in a softer dough. Non-targeted metabolomics analyses showed that Se inhibited yeast energy metabolism and promoted the synthesis of stress-resistance related components. Glutathione, glycerol, and linoleic acid contributed to the rheological property changes of the dough. The fractions and molecular weight distribution of protein demonstrated that the increase in yeast Se content resulted in the depolymerization of gluten. The intermolecular interactions, fluorescence spectrum and disulfide bond analysis showed that the disruption of intermolecular disulfide bond induced by Se-enriched yeast metabolites played an important role in the depolymerization of gluten.

Mechanism of Microwave Radiation-Induced Learning and Memory Impairment Based on Hippocampal Metabolomics.

The brain is complex and metabolically active, and the detection of metabolites plays an important role in brain development and diseases. Currently, there is a lack of research on the metabolic spectrum changes in learning and memory impairment, and hippocampal damage induced by microwave radiation from the metabolic perspective. Aiming to provide sensitive indicators for microwave radiation-induced brain damage and establish a foundation for understanding its injury mechanisms, this study employed non-targeted metabolomics to investigate metabolic fluctuations and key metabolic pathway alterations in rats' hippocampal tissue after microwave radiation. The memory and spatial exploration abilities of rats decreased after radiation. The postsynaptic densities were thickened in the MW group. The cholesterol sulfate, SM(d16:1/24:1(15Z)), and linoelaidylcarnitine were significantly increased after radiation, whereas etrahydrocorticosterone, L-phenylalanine, and histamine were significantly decreased after radiation. These metabolites were enriched in signaling pathways related to the inflammatory mediator regulation of transient receptor potential (TRP) channels, neuroactive ligand-receptor interaction, steroid hormone biosynthesis, and phenylalanine, tyrosine, and tryptophan biosynthesis. These findings indicate that microwave radiation causes spatial learning and memory dysfunction in rats and structural damage to hippocampal tissue.

The Biotransformation and Influence on the Functional Activities of Metabolites during the Fermentation of Elaeagnus moorcroftii Wall.ex Schlecht. Juice by Bifidobacterium animalis subsp. lactis HN-3.

Elaeagnus moorcroftii Wall.ex Schlecht. (EWS) has extensive nutrients and functional active ingredients, which makes it an excellent potential substrate for fermentation. The improvement in the antioxidant activity of Elaeagnus moorcroftii Wall.ex Schlecht. juice (EWSJ) fermented by Bifidobacterium animalis subsp. lactis HN-3 (B.an3) could be attributed to the metabolism and biotransformation of plant-based products by the bacterial strain. To reveal the underlying mechanism, non-targeted metabolomics was applied in this study. After fermentation, the structure of downregulated carbohydrates, amino acids, fatty acids, and flavonoids was changed by Bifidobacterium biotransformation (included four reductions, three hydrolyses, four isomerizations, three deglycosidations, and five other reactions). The structure of these converted upregulated products has a higher antioxidant ability to reduce free radicals than their precursors, such as the flavonoids in the form of hydrolyzed conjugates, amino acids with multiple sulfhydryls or hydroxys, carbohydrates with reactive oxygen on benzene rings and fatty acids with unsaturated bonds, short chains, and glycosides. These findings shed light on the mechanism of the metabolism and biotransformation of EWSJ by B.an3, facilitate the study of the interaction between probiotics and fermented plant-based products, and provide a theoretical basis for the development of Bifidobacterium-fermented plant products with stronger functional activities.

Identification of metabolites produced by six gut commensal Bacteroidales strains using non-targeted LC-MS/MS metabolite profiling.

As the most abundant gram-negative bacterial order in the gastrointestinal tract, Bacteroidales bacteria have been extensively studied for their contribution to various aspects of gut health. These bacteria are renowned for their involvement in immunomodulation and their remarkable capacity to break down complex carbohydrates and fibers. However, the human gut microbiota is known to produce many metabolites that ultimately mediate important microbe-host and microbe-microbe interactions. To gain further insights into the metabolites produced by the gut commensal strains of this order, we examined the metabolite composition of their bacterial cell cultures in the stationary phase. Based on their abundance in the gastrointestinal tract and their relevance in health and disease, we selected a total of six bacterial strains from the relevant genera Bacteroides, Phocaeicola, Parabacteroides, and Segatella. We grew these strains in modified Gifu anaerobic medium (mGAM) supplemented with mucin, which resembles the gut microbiota's natural environment. Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based metabolite profiling revealed 179 annotated metabolites that had significantly differential abundances between the studied bacterial strains and the control growth medium. Most of them belonged to classes such as amino acids and derivatives, organic acids, and nucleot(s)ides. Of particular interest, Segatella copri DSM 18205 (previously referred to as Prevotella copri) produced substantial quantities of the bioactive metabolites phenylethylamine, tyramine, tryptamine, and ornithine. Parabacteroides merdae CL03T12C32 stood out due to its ability to produce cadaverine, histamine, acetylputrescine, and deoxycarnitine. In addition, we found that strains of the genera Bacteroides, Phocaeicola, and Parabacteroides accumulated considerable amounts of proline-hydroxyproline, a collagen-derived bioactive dipeptide. Collectively, these findings offer a more detailed comprehension of the metabolic potential of these Bacteroidales strains, contributing to a better understanding of their role within the human gut microbiome in health and disease.

Inhibition of anaerobic digestion by various ammonia sources resulted in subtle differences in metabolite dynamics.

The impact of ammonia on anaerobic digestion performance and microbial dynamics has been extensively studied, but the concurrent effect of anions brought by ammonium salt should not be neglected. This paper studied this effect using metabolomics and a time-course statistical framework. Metabolomics provides novel perspectives to study microbial processes and facilitates a more profound understanding at the metabolic level. The advanced statistical framework enables deciphering the complexity of large metabolomics data sets. More specifically, a series of lab-scale batch reactors were set up with different ammonia sources added. Samples of nine time points over the degradation were analyzed with liquid chromatography-mass spectrometry. A filtering procedure was applied to select the promising metabolomic peaks from 1262 peaks, followed by modeling their intensities across time. The metabolomic peaks with similar time profiles were clustered, evidencing the correlation of different biological processes. Differential analysis was performed to seek the differences in metabolite dynamics caused by different anions. Finally, tandem mass spectrometry and metabolite annotation provided further information on the molecular structure and possible metabolic pathways. For example, the consumption of 5-aminovaleric acid, a short-chain fatty acid obtained from l-lysine degradation, was slowed down by phosphates. Overall, by investigating the effect of anions on anaerobic digestion, our study demonstrated the effectiveness of metabolomics in providing detailed information in a set of samples from different experimental conditions. With the statistical framework, the approach enables capturing subtle differences in metabolite dynamics between samples while accounting for the differences caused by time variations.

Refined metabolite profiling in the collateral circulation of chronic total occlusion of coronary arteries: Insights from a metabolomics investigation.

Background and aims: To investigate the disparities in coronary collateral circulation (CCC) and peripheral serum metabolites among patients presenting with chronic total occlusion (CTO) of the coronary arteries, a non-targeted metabolic approach was employed. Methods: A cohort of 22 patients diagnosed with CTO of coronary arteries in the context of coronary heart disease (CHD) was selected for blood sample collection from CCC and peripheral arteries. The patients were categorized into two groups, namely CTO-C and CTO-P. The Waters UPLC I-Class Plus is combined with the Q Exactive high-resolution mass spectrometer for metabolite separation and detection. The acquired raw data from mass spectrometry is subsequently imported into Compound Discoverer 3.2 software for comprehensive analysis, which seamlessly integrates the BGI Metabolome Database (BMDB), mzCloud database, and ChemSpider online database. Subsequently, the identified differential metabolites were subjected to a metabolic pathway enrichment analysis, as documented in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Results: A total of 403 differential metabolites were identified in CCC and peripheral serum samples from patients with CTO of coronary arteries in CHD. Compared to the CTO-P group, the CTO-C group exhibited decreased levels of metabolites such as Testosterone, dehydroepiandrosterone (DHA), deoxyacetone, while demonstrating increased levels of metabolites including Progesterone, androstanone, l-threonine. The biosynthesis pathway of steroid hormones emerges as the key metabolic pathway significantly associated with differential metabolites. Conclusions: Through metabolomics analysis, distinct differences in the CCC and peripheral serum metabolites have been identified among patients with CTO of coronary artery. Notably, a significant association between the steroid hormone biosynthesis pathway and CCC has been observed.

Rewiring cis-2-butene-1,4-dial mediated urinary metabolomics fingerprints of short-term exposure to furan.

Furan represents one of the dietary-sourced persistent organic pollutants and thermal processing contaminants. Given its widespread occurrence in food and various toxicological effects, accurately assessing furan exposure is essential for informing public health risks. Furan is metabolized to a reactive primary product, cis-2-butene-1,4-dial (BDA) upon absorption. Some of the resulting BDA-derived metabolites have been proposed as potential exposure biomarkers of furan. However, the lack of quantification for recognized and feasible furan biomarkers has hampered the development of internal exposure risk assessment of furan. In this study, we employed reliable non-targeted metabolomics techniques to uncover urinary furan metabolites and elucidate their chemical structures. We characterized 8 reported and 11 new furan metabolites derived from the binding of BDA with glutathione (GSH), biogenic amines, and/or amino acids in the urine of male rats subjected to varying doses of furan. Notably, a mono-GSH-BDA adduct named cyclic GSH-BDA emerged as a highly prospective specific biomarker of furan exposure, as determined by an ultrahigh-performance liquid chromatography-tandem mass spectrometry method. Cyclic GSH-BDA demonstrated a robust mass spectrometry ion response intensity and exhibited evident time- and dose response. Additionally, we conducted a comprehensive profiling of the kinetics of potential furan biomarkers over time to capture the metabolic dynamics of furan in vivo. Most urinary furan metabolites reached peak concentrations at either the first (3 h) or second (6 h) sampling time point and were largely eliminated within 36 h following furan treatment. The present study provides novel insights into furan metabolism and sheds light on the biomonitoring of furan exposure.

Inhibiting arachidonic acid generation mitigates aging-induced hyperinsulinemia and insulin resistance in mice.

BACKGROUND: Aging-related type 2 diabetes (T2DM) is characterized by hyperinsulinemia, insulin resistance, and ß-cell dysfunction. However, the underlying molecular mechanisms remain to be unclear. METHODS: We conducted non-targeted metabolomics to compare human serum samples from young adults (YA), elderly adults (EA), and elderly adults with diabetes (EA + DM) of Chinese population. Adult mice and aged mice were intragastrically administered with varespladib every day for two weeks and metabolic characteristics were monitored. Serum levels of arachidonic acid, insulin, and C-peptide, as well as serum activity of secretory phospholipase A2 (sPLA2) were detected in mice. Mouse islet perfusion assays were used to assess insulin secretion ability. Phosphorylated AKT levels were measured to evaluate insulin sensitivities of peripheral tissues in mice. RESULTS: Non-targeted metabolomics analysis of human serum samples revealed differential metabolic signatures among the YA, EA, and EA + DM groups. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed significant enhancement of arachidonic acid metabolism and glycerophospholipid metabolism in the EA group compared with the YA group. Further analysis identified two metabolic fluxes that favored the accumulation of arachidonic acid in the elderly. Increased levels of arachidonic acid were also confirmed in aged mice with hyperinsulinemia and insulin resistance, together with subsequent glucose intolerance. Conversely, inhibiting the generation of arachidonic acid with varespladib, an inhibitor of sPLA2, reduced aging-associated diabetes by improving hyperinsulinemia and hepatic insulin resistance in aged mice but not in adult mice. Islet perfusion assays also showed that varespladib treatment suppressed the enhanced insulin secretion observed in aged islets. CONCLUSIONS: Collectively, our findings uncover that arachidonic acid serves as a metabolic hub in Chinese elderly population. Our results also suggest that arachidonic acid plays a fundamental role in regulating ß-cell function during aging and point to a novel therapy for aging-associated diabetes.

Terpinen-4-ol Improves Lipopolysaccharide-Induced Macrophage Inflammation by Regulating Glutamine Metabolism.

Terpinen-4-ol (T-4-O) is an important component of tea tree oil and has anti-inflammatory effects. Currently, there are very few studies on the mechanisms by which T-4-O improves lipopolysaccharide (LPS)-induced macrophage inflammation. In this study, LPS-stimulated mouse RAW264.7 macrophages were used as a model to analyze the effects of T-4-O on macrophage inflammatory factors and related metabolic pathways in an inflammatory environment. The results showed that T-4-O significantly decreased the expression levels of inflammatory cytokines induced by LPS. Cellular metabolism results showed that T-4-O significantly decreased the ratio of the extracellular acidification rate and oxygen consumption rate. Non-targeted metabolomics results showed that T-4-O mainly affected glutamine and glutamate metabolism and glycine, serine, and threonine metabolic pathways. qPCR results showed that T-4-O increased the transcript levels of GLS and GDH and promoted glutamine catabolism. Western blotting results showed that T-4-O inhibited the mTOR and IκB, thereby decreasing NF-κB activity. The overall results showed that T-4-O inhibited mTOR phosphorylation to promote glutamine metabolism and increased cell oxidative phosphorylation levels, thereby inhibiting the expression of LPS-induced inflammatory cytokines.