Metabolite profiling of plasma and urine from rats with TNBS-induced acute colitis using UPLC-ESI-QTOF-MS-based metabonomics--a pilot study

6-Gingerol ameliorates ulcerative colitis by inhibiting ferroptosis based on the integrative analysis of plasma metabolomics and network pharmacology

6-Gingerol (6-G), an active ingredient of ginger with anti-inflammation and anti-oxidation properties, can treat ulcerative colitis (UC). However, its underlying mechanism is still unclear. In this study, the pharmacodynamic evaluation of 6-G for treating UC was performed, and the mechanism of 6-G in ameliorating UC was excavated by plasma metabolomics and network pharmacology analysis, which was further validated by experimental and molecular docking. The results showed that 6-G could notably reduce diarrhea, weight loss, colonic pathological damage, and inflammation in UC mice. Plasma metabolomic results indicated that 6-G could regulate 19 differential metabolites, and its metabolic pathways mainly involved linoleic acid metabolism and arachidonic acid metabolism, which were closely associated with ferroptosis. Moreover, 60 potential targets for 6-G intervention on ferroptosis in UC were identified by network pharmacology, and enrichment analysis revealed that 6-G suppressed ferroptosis by modulating lipid peroxidation. Besides, the integration of metabolomics and network pharmacology showed that the regulation of 6-G on ferroptosis focused on 3 key targets, including ALOX5, ALOX15, and PTGS2. Further investigation indicated that 6-G significantly inhibited ferroptosis by decreasing iron load and malondialdehyde (MDA), and enhanced antioxidant capacity by reducing the content of glutathione disulfide (GSSG) and increasing the levels of superoxide dismutase (SOD) and glutathione (GSH) in UC mice and RSL3-induced Caco-2 cells. Furthermore, molecular docking showed the high affinity of 6-G with the identified 3 key targets. Collectively, this study elucidated the potential of 6-G in ameliorating UC by inhibiting ferroptosis. The integrated strategy also provided a theoretical basis for 6-G in treating UC.

Effects of direct-fed microbial supplement on ruminal and plasma metabolome of early-lactation dairy cows: Untargeted metabolomics approach

We examined the effects of 2 multispecies direct-fed microbial (DFM) supplements on ruminal and plasma metabolome of early-lactation dairy cows using a high-coverage untargeted metabolomics approach. A total of 45 multiparous Holstein cows (41 ± 7 DIM) were enrolled for the 14-d pre-experimental and 91-d experimental period and were a subset from a lactation performance study, which used 114 cows. Cows were blocked using pre-experimental energy-corrected milk yield and randomly assigned within each block to 1 of 3 treatments: (1) corn silage-based diet with no DFM supplement (control; CON), (2) basal diet top-dressed with a mixture of Lactobacillus animalis and Propionibacterium freudenreichii at 3 × 109 cfu/d (PRO-A), or (3) basal diet top-dressed with a mixture of L. animalis, P. freudenreichii, Bacillus subtilis, and Bacillus licheniformis at 11.8 × 109 cfu/d (PRO-B). The basal diet was fed ad libitum daily as a TMR at 0600 and 1200 h for a duration of 91 d. Rumen fluid and blood samples were taken on d -3, 28, 49, 70, and 91 and immediately stored at -80°C. Before analysis, ruminal and plasma samples from d 28, 49, 70, and 91 were composited. An in-depth, untargeted metabolome profile of the composite rumen and plasma samples and the d -3 samples was developed by using a chemical isotope labeling/liquid chromatography-mass spectrometry (LC-MS)-based technique. Differentially abundant metabolites (taking into account fold change [FC] values and false discovery rates [FDR]) were identified with a volcano plot. In the rumen, compared with the CON diet, supplemental PRO-A increased (FC ≥1.2; FDR ≤0.05) the relative concentrations of 9 metabolites, including 2-hydroxy-2,4-pentadienoic acid, glutaric acid, quinolinic acid, and shikimic acid, and PRO-B increased relative concentrations of 16 metabolites, including 2-hydroxy-2,4-pentadienoic acid, glutaric acid, 16-hydroxypalmitic acid, and 2 propionate precursors (succinic and methylsuccinic acids). Relative to PRO-A, supplemental PRO-B increased (FC ≥1.2; FDR ≤0.05) relative rumen concentrations of 3 metabolites, 16-hydroxypalmitic acid, indole-3-carboxylic acid, and 5-aminopentanoic acid, but reduced relative rumen concentrations of 13 metabolites, including carnitine, threonic acid, and shikimic acid. Compared with the CON diet, relative concentrations of 13 plasma metabolites, including myxochelin A and glyceraldehyde, were increased (FC ≥1.2; FDR ≤0.05) by PRO-A supplementation, whereas those of 9 plasma metabolites, including 4-(2-aminophenyl)-2,4-dioxobutanoic acid, N-acetylornithine, and S-norlaudanosolin, were reduced (FC ≤0.83; FDR ≤0.05). Supplemental PRO-B increased (FC ≥1.2; FDR ≤0.05) relative concentrations of 9 plasma metabolites, including trans-o-hydroxybenzylidenepyruvic acid and 3-methylsalicylaldehyde, and reduced relative concentrations of 4 plasma metabolites, including β-ethynylserine and kynurenine. Pathway analysis of the differentially abundant metabolites in both rumen and plasma revealed that these metabolites are involved in AA and fatty acid metabolism and have antimicrobial and immune-stimulating properties. The results of this study demonstrated that dietary supplementation with either PRO-A or PRO-B altered the plasma and ruminal metabolome. Notably, ruminal and plasma metabolites involved in the metabolism of AA and fatty acids and those with immunomodulatory properties were altered by either or both of the 2 microbial additives.

Bifunctional Ti4+-modified paper for selective extraction or removal of phospholipids and paper spray mass spectrometry for bioanalysis in urine and plasma

BACKGROUND

Phospholipids (PLs) are major constituents of cell membranes, play important roles in cell proliferation and death, as well as in signal transduction, and therefore are relevant biomarkers for different pathologies. On the other hand, when the analysis of small compounds, such as therapeutics in blood is desired, then phospholipids are part of the matrix and cause serious interference during analysis. Currently, both the analysis and removal of PLs from biological samples are limited by extensive sample preparation and instrumental separation.

RESULTS

A fast and simple quantitative Ti4+-modified paper spray tandem mass spectrometric (TiPS-MS/MS) method was established in urine, where the enrichment of phospholipids was achieved, as well as reduction of matrix effects (primarily caused by high salt content) that ultimately led to improved sensitivity and selectivity. The method could achieve a physiologically relevant limit of detection (0.01-0.03 μg mL-1). Also, the usefulness of the Ti4+-modified paper was investigated in the opposite mode, namely for the selective removal of phospholipids from matrices such as plasma. Clonidine is used as model compound, as the detection of this compound is known to suffer from ion suppression by phospholipids. Compared with blank paper spray tandem mass spectrometry, the limit of detection could be improved from 0.3 μg mL-1 to 0.03 μg mL-1 by employing a Ti4+-modified paper on top of the spray tip to capture phospholipids from the sample.

SIGNIFICANCE AND NOVELTY

A novel Ti4+-modified paper was developed to allow for rapid solid-phase extraction of phospholipids from urine or selective removal from plasma, followed by direct paper spray mass spectrometric detection as a fast and convenient sample preparation and analysis combination. The paper properties are based on the Ti4+ metal ion, which can selectively bind phosphate-containing compounds under acidic conditions, and its applicability was demonstrated in relevant biological matrices.

Systematic Review: Urine Biomarker Discovery for Inflammatory Bowel Disease Diagnosis

Inflammatory bowel diseases (IBDs) are chronic, heterogeneous, and inflammatory conditions mainly affecting the gastrointestinal tract. Currently, endoscopy is the gold standard test for assessing mucosal activity and healing in clinical practice; however, it is a costly, time-consuming, invasive, and uncomfortable procedure for the patients. Therefore, there is an urgent need for sensitive, specific, fast and non-invasive biomarkers for the diagnosis of IBD in medical research. Urine is an excellent biofluid for discovering biomarkers because it is non-invasive to sample. In this review, we aimed to summarize proteomics and metabolomics studies performed in both animal models of IBD and humans that identify urinary biomarkers for IBD diagnosis. Future large-scale multi-omics studies should be conducted in collaboration with clinicians, researchers, and industry to make progress toward the development of sensitive and specific diagnostic biomarkers, thereby making personalized medicine possible.

Metabolomics Study of Shaoyao Plants Decoction on the Proximal and Distal Colon in Mice with Dextran Sulfate Sodium-Induced Colitis by UPLC-Q-TOF-MS

Purpose

Shaoyao decoction (SYD) is a traditional Chinese medicine used to treat ulcerative colitis (UC). The exact mechanism of action of SYD in UC treatment is still unclear. Here, we examined the therapeutic effects of SYD in mice with dextran sulfate sodium (DSS)-induced colitis and explored the underlying mechanism.

Methods

The experimental group was divided into normal control, UC, and SYD treatment groups. The UC model of C57BL/6 mice was induced using 3% (w/v) DSS for 7 days. SYD was orally administered for 7 days. The proximal and distal colonic metabolic profiles were detected using quadrupole-time-of-flight mass spectrometry-based untargeted metabolomics.

Results

SYD significantly increased weight, reduced disease activity index scores, and ameliorated colon length shortening and pathological damage in mice. In the distal colon, SYD increased the abundance of phosphatidic acid and lysophosphatidylethanolamine and decreased the abundance of lactosylceramide, erythrodiol 3-palmitate, and lysophosphatidylcholine. In the proximal colon, SYD increased the abundance of palmitic acid, cyclonormammein, monoacylglyceride, 13S-hydroxyoctadecadienoic acid, and ceanothine C and decreased the abundance of tetracosahexaenoic acid, phosphatidylserine, and diglyceride.

Conclusion

Our findings revealed that SYD could alleviate UC by regulating metabolic dysfunction, which provides a reference for further studies on SYD.

Serum Metabolic Correlates of the Antibody Response in Subjects Receiving the Inactivated COVID-19 Vaccine

BACKGROUND

Metabolites are involved in biological process that govern the immune response to infection and vaccination. Knowledge of how metabolites interact with the immune system during immunization with the COVID-19 vaccine is limited. Here, we report that the serum metabolites are correlated with the magnitude of the antibody response in recipients receiving the inactivated COVID-19 vaccine, which provides critical information for studying metabolism regarding the human immune response to vaccination.

METHODS

106 healthy volunteers without history of SARS-CoV-2 infection or vaccination were prospectively enrolled to receive the primary series of two doses of inactivated whole-virion SARS-CoV-2 vaccine. The serum samples were collected 2-4 weeks after the second dose. The magnitude of the anti-RBD antibody was quantified using surrogate virus neutralization tests. The profile of metabolites in serum was identified using untargeted metabolomics analysis.

RESULTS

The level of anti-RBD antibody 14-28 days after the second dose was significantly elevated and its interpersonal variability was diverse in a wide range. Thirty-two samples at extremes of the anti-RBD antibody titer were selected to discover the metabolic correlates. Two hundred and fifteen differential metabolites associated with antibody response independent of body mass index were identified. Pregnenolone and sphingolipid metabolism might be involved in the modulation of the human antibody response to the inactivated COVID-19 vaccine.

CONCLUSION

We discovered key metabolites as well as those with a related functional significance that might modulate the human immune response to vaccination.

Gut microbiota-derived metabolites contribute negatively to hindgut barrier function development at the early weaning goat model

Early weaning induces intestinal injury, leading to a series of long-term symptoms such as inflammation, malabsorption and diarrhea. In this study, we hypothesized that microbes and their metabolites modulate the host's inflammatory response to early weaning stress in a goat model. A total of 18 female Tibetan goat kids (n = 9) were weaned from their mothers at 28 d (D28) and 60 d (D60) postpartum. D60 and D28 groups were fed the same solid diet ad libitum from weaning to 75 d of age. The colonic epithelium was subject to RNA-sequencing, the caecal digesta metabolomics were assessed by liquid chromatography–tandem mass spectrometry (LC-MS/MS), and the caecal microbiota composition was analysed by 16S ribosomal RNA gene sequencing. We found that early weaning substantially increased the colonic pro-apoptotic gene expression of B-cell lymphoma associated X (Bax), caspase-9, and caspase-3, and decreased the expression of zonula occludens-1 (ZO-1) and claudin-1 (P < 0.01). In addition, a significant Bacteroides acidifaciens enrichment was observed in the hindgut of early-weaned goats (P < 0.01), which negatively correlated with lysophosphatidylcholine products. Similarly, the chemokine signaling, IL-17 signaling, and peroxisome proliferators-activated receptor (PPAR) signaling pathways were upregulated in the colonic mucosa of the early-weaned goats. By applying caecal microbiota transplantation from goats to defaunated C57/6J mice, we confirmed that caecal microbiota of D28 goat kids increased the relative abundance of B. acidifaciens and significantly up-regulated the genes of Bax, G protein–coupled receptor (GPR) 109A, GPR 43, fatty acid binding protein 6, nuclear receptor subfamily 1 group H member 3, angiotensin converting enzyme 2, and IL-6 expression (P < 0.05), and decreased ZO-1, and claudin-1 protein expression in the mice jejunum and colon (P < 0.001). These results proposed that the hindgut microbiota and metabolites mediate the barrier function weakening during early weaning, and the relative abundance of B. acidifaciens was negatively correlated with the hindgut barrier gene expression. This study demonstrates how weaning stress can affect key host–microbe interaction regulators in the hindgut, in a lysophosphatidylcholine dependent and independent manner. Furthermore, based on our mice data, these results are transferable to other mammal species.

Biomarkers of Metabolomics in Inflammatory Bowel Disease and Damp-Heat Syndrome: A Preliminary Study

Aims

This study aims to investigate the potential biomarkers of inflammatory bowel disease (IBD) and IBD with damp-heat syndrome (IBD-DH) by metabolomics.

Methods

Plasma and urine samples were collected from 15 healthy controls and 30 IBD patients, including 15 IBD-DH and 15 IBD with spleen deficiency syndrome (IBD-SD), which was coded as SF8G and SF70 according to the International Classification of Diseases Eleventh Revision (ICD-11) issued by World Health Organization. Pseudotargeted metabolomics method was used based on ultra-high-performance liquid chromatography-high-resolution mass spectrometry and triple-quadrupole mass spectrometry.

Results

Under the condition of false discovery rate (FDR) < 0.05, variable importance projection (VIP) > 1.0, and fold change (FC) > 1.5 or < 2/3, we found 57 plasma differential metabolites and 20 urinary differential metabolites in IBD. Then, with area under the curve (AUC) ≥ 0.85 and FC ≥ 2 or ≤ 0.3, 11 potential biomarkers were identified, such as acylcarnitine (ACar 20:4, ACar 18:1, and ACar 20:3), 3-indoleacetic acid, hippuric acid, and dehydroepiandrosterone sulfate, which is related to intestinal microbiota and immune response. However, less obvious differences were observed in IBD-DH when compared with IBD-SD. Under the condition of FDR < 0.2, VIP >1.0, and FC > 1.5 or < 2/3, we identified 16 plasma differential metabolites. In urine samples, IBD-DH and IBD-SD had the same metabolite pattern. With AUC ≥ 0.80, 7 differential plasma metabolites, mainly glycerophospholipids, were identified in IBD-DH. Kyoto Encyclopedia of Genes and Genomes analysis indicated that metabolic pathways, such as citrate cycle and amino acids metabolism, were mainly responsible for the distinction between IBD and healthy controls, whereas glycerophospholipid metabolism perturbation was not only a manifestation of IBD but also an important pathway to distinguish two subtypes defined by traditional medicine, IBD-DH and IBD-SD.

Conclusion

In this study, we found that several metabolites of aromatic acids and lipid derivatives could act as potential biomarkers to discriminate IBD from healthy controls. Glycerophospholipids metabolites might be used to differentiate IBD-DH from IBD-SD.

Lizhong Decoction () Ameliorates Ulcerative Colitis in Mice via Regulation of Plasma and Urine Metabolic Profiling

OBJECTIVE

To elucidate the mechanism of Lizhong Decoction (LZD, ) in treating dextran sodium sulfate (DSS)-induced colitis in mice based on metabonomics.

METHODS

Thirty-six mice were randomly divided into 6 groups, including normal, model, low- (1.365 g/kg), medium- (4.095 g/kg) and high dose (12.285 g/kg) LZD and salazosulfadimidine (SASP) groups, 6 mice in each group. Colitis model mice were induced by DSS admistration for 7 days, and treated with low, medium and high dose LZD extract and positive drug SASP. Metabolic comparison of DSS-induced colitis and normal mice was investigated by using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass (UPLC-Q-TOF/MS) combined with Metabolynx™ software.

RESULTS

The metabolic profiles of plasma and urine in colitis mice were distinctly ameliorated after LZD treatment (P<0.05). Potential biomarkers (9 in serum and 4 in urine) were screened and tentatively identified. The endogenous metabolites were mainly involved in primary bile acid, sphingolipid, linoleic acid, arachidonic acid, amino acids (alanine, aspartate, and glutamate), butanoate and glycerophospholipid metabolism in plasma, and terpenoid backbone biosynthesis, glycerophospholipid and tryptophan metabolism in urine. After LZD treatment, these markers notably restored to normal levels.

CONCLUSIONS

The study revealed the underlying mechanism of LZD on amelioration of ulcerative colitis based on metabonomics, which laid a foundation for further exploring the pathological and physiological mechanism, early diagnosis, and corresponding drug development of colitis.

RNase1 can modulate gut microbiota and metabolome after Aeromonas hydrophila infection in blunt snout bream

Pancreatic ribonuclease (RNase1) of Megalobrama amblycephala exhibits both antimicrobial and digestive activity. The gut microbiome improve the digestion and metabolic capacity and enhance the functioning of the immune system of the host against pathogenic bacteria. In this study, we aimed to assess the protective effect of RNase1 on Aeromonas hydrophila-induced inflammation and intestinal microbial metabolism. Megalobrama amblycephala were randomly divided into three groups: control (injected PBS), infection (A. hydrophila-injected), and treatment group (RNase1 pretreatment 24 h before the A. hydrophila injection). The morphological symptoms were significantly alleviated by RNase1. RNase1 reshaped the perturbed gut microbiota by upregulating Proteobacteria and Vibrio richness and downregulating Firmicutes, Chlamydiae, Bacillus, and Gemmobacter richness. The lysophosphatidylcholine, (±) 17 HETE, D- (+) -cellobiose, and PC (20:5) in the treatment group were restored by RNase 1 protein treatment to the level of the control group. In the treatment group, phospholipid metabolism, fatty acid metabolism, glucose metabolism and lipid metabolism were different from the control and infection groups. The proinflammatory factors concentration in intestinal samples significantly increased after A. hydrophila infection. Our results revealed that RNase1 plays an important role in resistance to pathogen invasion, reducing inflammation, and improving intestinal function, thus inhibiting the occurrence of disease.

A narrative review of urinary phospholipids: from biochemical aspect towards clinical application

As a newly emerged discipline, lipidomic studies have focused on the comprehensive characterization and quantification of lipids in a given biological system, which has remarkably advanced in recent years owing to the rapid development of analytical techniques, especially mass spectrometry. Among diverse lipid classes, phospholipids, which have fundamental roles in the formation of cellular membranes, signaling processes, and bioenergetics have gained momentum in several fields of research. The altered composition, concentration, spatial distribution, and metabolism of phospholipids in cells, tissues, and body fluids have been elucidated in various human diseases such as cancer, inflammation, as well as cardiovascular and metabolic disorders. Among the different kinds of phospholipid sources in the human body, urine has not been extensively investigated in recent years owing to the extremely low concentrations of phospholipids and high levels of salts and other contaminants, which can interfere with precise detection. However, with profound advances and rapid expansion in analytical methods, urinary phospholipids have attracted increasing attention in current biomedical research as urine is an easily available source for the discovery of noninvasive biomarkers. In this review, we provide an overview of urinary phospholipids, including their biochemical aspects and clinical applications, aimed at promoting this field of research.

Berberine Suppresses Colonic Inflammation in Dextran Sulfate Sodium-Induced Murine Colitis Through Inhibition of Cytosolic Phospholipase A2 Activity

Ulcerative colitis (UC) causes chronic inflammation and damage to the colonic mucosal layer. Recent studies have reported significant changes in phosphatidylcholine (PC) and lysophosphatidylcholine (LPC) in UC patients and oral administration of PC has considerable therapeutic effects against UC, suggesting the metabolism of phosphatidylcholine may be involved in the UC development. Our previous work has demonstrated that berberine effectively suppresses inflammation and protects colonic mucosa injury in DSS-induced colitic mice. However, whether the therapeutic effects of berberine are attributed to its action on the PC metabolism remains unknown. In the present study, we have shown that berberine significantly reduces the lysophosphatidylcholine (LPC) levels in the sera of DSS-induced experimental colitis mice and LPS-stimulated macrophage RAW 264.7 cells. The cytosolic phospholipase A2a (PLA2G4A), an enzyme for hydrolyzing PC to LPC, was found to be up-regulated in the colon tissue of experimental colitis mice and inflamed macrophage RAW 264.7 cells. We then demonstrated berberine inhibits the phosphorylation of cytosolic phospholipase A2a (PLA2G4A) in the colon tissue of experimental colitis mice and inflamed macrophage RAW 264.7 cells. Subsequently, we revealed berberine suppressed the expression of pro-inflammatory factors including TNF-alpha and IL-6 through regulating PLA2G4A dysfunction in macrophage RAW 264.7 cells. Mechanistically, we found that berberine directly binds to PLA2G4A and inhibits MAPK/JNK signaling pathway to inhibit PLA2G4A activity in inflammatory status. Therefore, we concluded that berberine inhibits colonic PLA2G4A activity to ameliorate colonic inflammation in experimental colitic mice, suggesting modulation of the PC metabolism via PLA2G4A might be beneficial for establishing new therapies strategy for UC.

Ultraperformance Liquid Chromatography Coupled with Quadrupole Time-of-Flight Mass Spectrometry-Based Metabolomics and Lipidomics Identify Biomarkers for Efficacy Evaluation of Mesalazine in a Dextran Sulfate Sodium-Induced Ulcerative Colitis Mouse Model

This study aims to identify biomarkers for evaluating the therapeutic efficacy of mesalazine on ulcerative colitis by metabolomics and lipidomics. A dextran sulfate sodium-induced mouse model was used. The disease status was assessed by a disease activity index, the TNF-α level of colon was measured by an enzyme-linked immunosorbent assay, and the pathological changes of colon tissue was examined by hematoxylin-eosin staining. Serum metabolomics and lipidomics analysis based on ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry were applied to decipher the metabolic profile changes. Multivariate analysis was applied to differentiate the metabolites of controls, models, and mesalazine-treated mice. By the receiver operating characteristic (ROC) analysis, 40 differential metabolites with an area under curve (AUC) >0.80 were screened out between control and model groups. Among them, four potential biomarkers (palmitoyl glucuronide, isobutyrylglycine, PC (20:3 (5Z, 8Z, 11Z)/15:0) and L-arginine) had a signficantly reversed level of peak areas in the mesalazine group, and three of them were closely correlated with mesalazine efficacy by linear regression analysis. Furthermore, metabolic pathway analysis revealed several dysregulated pathways in colitis mice, including glycerophospholipid metabolism, pyrimidine metabolism, linoleic acid metabolism, arginine biosynthesis, etc. This study indicates that serum metabolomics is a useful approach that can noninvasively evaluate the therapeutic effect and provide unique insights into the underlying mechanism of mesalazine.

Inbreeding Alters the Gut Microbiota of the Banna Minipig

Simple Summary

The mammalian gut microbiota is an indispensable part of host health. The gut microbiota plays a crucial role in nutrient digestibility, preventing colonization of pathogens and maintaining the host immune system. Host genetics has been conclusively shown to closely related to gut microbiota. Inbreeding can cause a decrease of the host’s genetic diversity, however, remarkably little is understood about the gut microbiota of pigs during inbreeding. The Banna minipig inbred is the world’s first successful large mammalian experimental animal inbred line since 1980 from full and half-siblings of the Diannan small-ear pig. Now, Banna minipig inbred has been inbred for over 37 generations, and the inbreeding coefficient is more than 99%. This study is the first to characterize and compare the composition and function of gut microbiota between the Diannan small-ear pig and Banna minipig inbred, aiming to better understand the influence of inbreeding on the gut microbiota.

Abstract

The gut microbiota coevolve with the host and can be stably transmitted to the offspring. Host genetics plays a crucial role in the composition and abundance of gut microbiota. Inbreeding can cause a decrease of the host’s genetic diversity and the heterozygosity. In this study, we used 16S rRNA gene sequencing to compare the differences of gut microbiota between the Diannan small-ear pig and Banna minipig inbred, aiming to understand the impact of inbreeding on the gut microbiota. Three dominant bacteria (Stenotrophlomonas, Streptococcus, and Lactobacillus) were steadily enriched in both the Diannan small-ear pig and Banna minipig inbred. After inbreeding, the gut microbiota alpha diversity and some potential probiotics (Bifidobacterium, Tricibacter, Ruminocaccae, Christensenellaceae, etc.) were significantly decreased, while the pathogenic Klebsiella bacteria was significantly increased. In addition, the predicted metagenomic analysis (PICRUSt2) indicated that several amino acid metabolisms (‘‘Valine, leucine, and isoleucine metabolism’’, ‘‘Phenylalanine, tyrosine, and tryptophan biosynthesis’’, ‘‘Histidine metabolism’’) were also markedly decreased after the inbreeding. Altogether our data reveal that host inbreeding altered the composition and the predicted function of the gut microbiome, which provides some data for the gut microbiota during inbreeding.

Disturbance of Fatty Acid Desaturation Mediated by FADS2 in Mesenteric Adipocytes Contributes to Chronic Inflammation of Crohn's Disease

BACKGROUND AND AIMS

The aim of this study was to investigate the metabolic profile of mesenteric adipocytes and the correlations between key metabolic changes and local inflammation in the context of Crohn's disease [CD].

METHODS

Metabolic dysfunction was shown to be regulated by fatty acid desaturase-2 [FADS2], through metabolomics and functional analyses of mesenteric adipose tissue biopsies and primary mesenteric adipocytes isolated from surgical specimens collected from CD patients and control subjects. FADS2 was overexpressed in vitro and in vivo using a lentiviral vector and an adeno-associated virus [AAV], respectively. The interaction between mesenteric adipocytes and inflammation responses was evaluated by establishing a cell coculture system and a FADS2-AAV treated animal model; 3T3-L1 cells were used to elucidate the mechanism underlying FADS2 deregulation.

RESULTS

We observed significant changes in the levels of metabolites involved in the multi-step synthesis of long-chain polyunsaturated fatty acids [PUFAs]. Gas chromatography analysis revealed impaired desaturation fluxes towards the n-6 and n-3 pathways, which are associated with reduced FADS2 activity in human mesentery tissue. Decreased FADS2 expression at both mRNA and protein levels was confirmed in surgical specimens. The restoration of FADS2 expression, which allows for the endogenous conversion of n-3 fatty acids into proresolving lipid mediators, resulted in a significant reduction in pro-inflammatory macrophage infiltration and attenuated expression of inflammatory cytokines or adipokines.

CONCLUSIONS

These findings indicate that impaired fatty acid desaturation and lipid mediator imbalance within mesenteric adipose tissue contributes to chronic inflammation in CD. The therapeutic role of FADS2 may lead to improved CD treatment.

Integrated study of metabolomics and gut metabolic activity from ulcerative colitis to colorectal cancer: The combined action of disordered gut microbiota and linoleic acid metabolic pathway might fuel cancer

Colorectal cancer (CRC) is one of the most serious complications of ulcerative colitis (UC). Altered gut microbiota is implicated in the development of CRC and metabolic perturbations are often associated with changes in the gut microbiome composition. Given the links between gut microbiome and the metabolic profiles in the body, an approach involving ultra-high-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC-Q-TOF-MS/MS) metabolomics and 16S rDNA sequencing technology was applied to trace the development UC into CRC in rats. The study identified 11 differential metabolites related to both UC and CRC, which mainly referred to the linoleic acid metabolism. Among these, linoleic acid and 12‑hydroxy‑8,10-octadecadienoic acid could serve as key biomarkers for the development of UC into CRC. Besides, a significant change was observed in the microflora structure during the development from UC to CRC; this mainly involved a gradual increase in Escherichia-Shigella and a gradual decrease in Lactobacillus. In addition, Pearson's correlation analysis revealed strong correlations between intestinal microflora-related metabolites and specific intestinal microflora, which indicated both of them can promote the transition of UC to CRC. The results of the present study provided positive support for the involvement of intestinal microflora and host metabolism in the pathophysiological mechanism that is responsible for the development of UC into CRC. This information can help understand the risk for CRC that accompanies a diagnosis of UC and also provide different means of targeting these differential metabolites and intestinal microbiota to avoid UC-induced CRC.

Translational Potential of Metabolomics on Animal Models of Inflammatory Bowel Disease-A Systematic Critical Review

In the development of inflammatory bowel disease (IBD), the gut microbiota has been established as a key factor. Recently, metabolomics has become important for understanding the functional relevance of gut microbial changes in disease. Animal models for IBD enable the study of factors involved in disease development. However, results from animal studies may not represent the human situation. The aim of this study was to investigate whether results from metabolomics studies on animal models for IBD were similar to those from studies on IBD patients. Medline and Embase were searched for relevant studies up to May 2017. The Covidence systematic review software was used for study screening, and quality assessment was conducted for all included studies. Data showed a convergence of ~17% for metabolites differentiated between IBD and controls in human and animal studies with amino acids being the most differentiated metabolite subclass. The acute dextran sodium sulfate model appeared as a good model for analysis of systemic metabolites in IBD, but analytical platform, age, and biological sample type did not show clear correlations with any significant metabolites. In conclusion, this systematic review highlights the variation in metabolomics results, and emphasizes the importance of expanding the applied detection methods to ensure greater coverage and convergence between the various different patient phenotypes and animal models of inflammatory bowel disease.

Probiotic treatment induced change of inflammation related metabolites in IBS-D patients/double-blind, randomized, placebo-controlled trial

There have been many studies suggesting that probiotics are effective in patients with diarrhea-predominant irritable bowel syndrome (IBS-D). However, its mechanism of action as well as prediction of response is still to be elucidated. In the present study, to find out metabolomic characteristics of probiotic effect in IBS-D, we compared IBS symptom changes and metabolomic characteristics in the subjects' urine samples between multi-strain probiotics (one strain of Lactobacillus sp. and four strains of Bifidobacterium sp.) group (n = 32) and placebo group (n = 31). After 8 weeks' administration (3 times/day), dissatisfaction in bowel habits and stool frequencies were significantly improved. Also, probiotics group had significantly changed seven metabolites including palmitic acid methyl ester (PAME) and 4,6-dihydroxyquinoline, 4-(2-aminophenyl)-2,4-dioxobutanoic acid (DOBA). According to IBS-SSS and IBS-QoL questionnaires, IBS-SSS responders showed higher PAME levels and IBS-QoL responders showed lower DOBA levels. This suggests potential role of these metabolites as a biomarker to predict probiotics effect in IBS-D patients.

Acute and short-term administrations of delta-9-tetrahydrocannabinol modulate major gut metabolomic regulatory pathways in C57BL/6 mice

Delta-9-tetrahydrocannabinol (THC) is the primary psychoactive compound in Cannabis, which is studied extensively for its medicinal value. A central gap in the science is the underlying mechanisms surrounding THC's therapeutic effects and the role of gut metabolite profiles. Using a mass-spectrometry based metabolomics, we show here that intraperitoneal injection of THC in C57BL/6 mice modulates metabolic profiles that have previously been identified as integral to health. Specifically, we investigated the effects of acute (single THC injection denoted here as '1X') and short -term (five THC injections on alternate days denoted as '5X') THC administration on fecal and intestinal tissue metabolite profiles. Results are consistent with the hypothesis that THC administration alters host metabolism by targeting two prominent lipid metabolism pathways: glycerophospholipid metabolism and fatty acid biosynthesis.

Metabolomics of Clinical Poisoning by Aconitum Alkaloids Using Derivatization LC-MS

The root of Aconitum kusnezoffii (Caowu in Chinese, CW) is not only commonly used as a traditional Chinese medicine (TCM), but also served as a tonic in China. Due to its high toxicity, clinical poisoning cases induced by CW have frequently been reported. However, the mechanism is still unclear. In this study, Aconitum alkaloids and altered endogenous metabolites in CW poisoning patients were investigated to elucidate the possible intoxication mechanism. Eighteen alkaloids, including 6 toxic diester diterpenoid alkaloids (DDAs), were determined from the sera of patients. At the same time, 5-(diisopropylamino)amylamine (DIAAA) derivatization-ultrahigh performance liquid chromatography- quadrupole-time of flight mass spectrometry (UHPLC-Q-TOF/MS) approach was applied in the metabolomics analysis to find much more carboxyl-containing metabolites (CCMs), which are the essential components for life and critical to elucidate the mechanism of toxicity. As a result, 32 altered metabolites after poisoning were identified. Among them, hydroxyeicosatetraenoic acids (HETEs) and some dicarboxylic acids were first found to be related to Aconitum alkaloids toxicity. Finally, biological pathway analysis indicated that the significantly changed metabolites were primarily involved in amino acid metabolism, TCA cycle, fatty acid metabolism, pyruvate metabolism, arachidonic acid metabolism, sphingolipid metabolism and so on. These results can not only provide more information on the mechanism of CW intoxication but also help the clinical diagnosis of CW poisoning.

Effects of sulfur-fumigation on the pharmacokinetics, metabolites and analgesic activity of Radix Paeoniae Alba

ETHNOPHARMACOLOGICAL RELEVANCE

Radix Paeoniae Alba (Baishao, BS), one of the most commonly used traditional Chinese medicinal herbs, has many pharmacological effects including analgesic activity. Previous studies found that sulfur-fumigation, a post-harvest handling process developed to prevent mold contamination of medicinal herbs, altered the quality of BS. However, whether sulfur-fumigation affects the pharmacokinetics, safety and efficacy of BS warrants further investigation.

AIM OF THE STUDY

To evaluate the feasibility of sulfur-fumigation as a post-harvest handling process of BS from the viewpoints of pharmacokinetics, safety and efficacy.

MATERIALS AND METHODS

The pharmacokinetic behaviors of four active components of BS and one characteristic component of sulfur-fumigated BS (S-BS) were evaluated by high performance liquid chromatography triple quadrupole mass spectrometry (HPLC-TQ-MS/MS). The safety was investigated using ultra high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS/MS) based metabolomics approach after intragastric (i.g.) administration of non-fumigated BS (N-BS) and S-BS in rats. The analgesic efficacy was compared using hot-plate test in mice, after i.g. administration of N-BS and S-BS, at both high and low dosages.

RESULTS

Systemic exposures of paeoniflorin and oxypaeoniflorin, two analgesic components of BS, were significantly decreased in the S-BS treated group compared to the N-BS treated group, while paeoniflorin sulfonate, one of the sulfur-containing derivatives of S-BS, was detected in all time-points of S-BS treated group with the area under the plasma concentration-time curve (AUC_0-t) and the maximum plasma concentration (C_max) as high as 7077.06 ± 2232.97ng/mL*h and 1641.42 ± 634.79ng/mL respectively, which indicated that sulfur-fumigation altered the pharmacokinetic behaviors of BS. Besides, paeoniflorin sulfonate and its four metabolites with ambiguous toxicities, as well as one endogenous metabolite p-cresol glucuronide, the biomarker of disordered homeostasis of intestinal bacteria and bile acid, were identified as the characteristic metabolites in S-BS administered rats, suggesting that sulfur-fumigation reduced the safety of BS. Furthermore, the analgesic effects at both low and high dosages were decreased in different extent when compared to N-BS administered groups, indicating that sulfur-fumigation weakened the efficacy of BS.

CONCLUSION

Sulfur-fumigation altered the pharmacokinetics, as well as reduced the safety and efficacy of BS, suggesting that sulfur-fumigation is not recommended for post-harvest handling of BS.

Antibiotic Treatment Preventing Necrotising Enterocolitis Alters Urinary and Plasma Metabolomes in Preterm Pigs

Necrotising enterocolitis (NEC) is a serious gut inflammatory condition in premature neonates, onset and development of which depend on the gut microbiome. Attenuation of the gut microbiome by antibiotics can reduce NEC incidence and severity. However, how the antibiotics-suppressed gut microbiome affects the whole-body metabolism in NEC-sensitive premature neonates is unknown. In formula-fed preterm pigs, used as a model for preterm infants, plasma and urinary metabolomes were investigated by LC-MS and ¹H NMR, with and without antibiotic treatment immediately after birth. While it reduced the gut microbiome density and NEC lesions as previously reported, the antibiotic treatment employed in the current study affected the abundance of 44 metabolites in different metabolic pathways. In antibiotics-treated pigs, tryptophan metabolism favored the kynurenine pathway, relative to the serotonin pathway, as shown by specific metabolites. Metabolites associated with the gut microbiome, including 3-phenyllactic acid, 4-hydroxyphenylacetic acid, and phenylacetylglycine, all from phenylalanine, and three bile acids showed lower levels in the antibiotics-treated pigs where the gut microbiome was extensively attenuated. Findings in the current study warrant further investigation of metabolic and developmental consequences of antibiotic treatment in preterm neonates.

Patchouli oil ameliorates acute colitis: A targeted metabolite analysis of 2,4,6-trinitrobenzenesulfonic acid-induced rats

The incidence of inflammatory bowel disease (IBD), characterized by chronic, relapsing intestinal inflammation, has continually increased in recent years. A previous study by our group identified five potential metabolic markers possibly associated with the pathology of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced IBD in rats. The present study aimed to examine the potential therapeutic effects of the essential oil of Pogostemon cablin (also known as patchouli; PO) on TNBS-induced rats and investigate the concomitant metabolic changes by targeting the previously identified potential markers. Pogostemon cablin is widely used to treat gastrointestinal diseases, including IBD, in China. The results of the present study showed that PO (270 mg/kg, rectal instillation) significantly alleviated colonic damage and reduced disease activity indicators and colonic myeloperoxidase in TNBS-induced rats. In addition, a targeted metabolic profiling study identified that four metabolites were elevated in the urine of the animals in the TNBS group, which were significantly inhibited by treatment with PO: Two tryptophan metabolites [4-(2-aminophenyl)-2,4-dioxobutanoic acid and 4,6-cihydroxyquinoline] and two gut microbial metabolites (phenylacetylglycine and p-cresol glucuronide). Taken together, these findings suggested that PO ameliorated the symptoms of TNBS-induced IBD and reversed the metabolic changes potentially associated with TNBS-induced IBD in rats.

Inbred Mouse Populations Exhibit Intergenerational Changes in Intestinal Microbiota Composition and Function Following Introduction to a Facility

Inbred mice are used to investigate many aspects of human physiology, including susceptibility to disease and response to therapies. Despite increasing evidence that the composition and function of the murine intestinal microbiota can substantially influence a broad range of experimental outcomes, relatively little is known about microbiome dynamics within experimental mouse populations. We investigated changes in the intestinal microbiome between C57BL/6J mice spanning six generations (assessed at generations 1, 2, 3, and 6), following their introduction to a stringently controlled facility. Fecal microbiota composition and function were assessed by 16S rRNA gene amplicon sequencing and liquid chromatography mass spectrometry, respectively. Significant divergence of the intestinal microbiota between founder and second generation mice, as well as continuing inter-generational variance, was observed. Bacterial taxa whose relative abundance changed significantly through time included Akkermansia, Turicibacter, and Bifidobacterium (p < 0.05), all of which are recognized as having the potential to substantially influence host physiology. Shifts in microbiota composition were mirrored by corresponding differences in the fecal metabolome (r = 0.57, p = 0.0001), with notable differences in levels of tryptophan pathway metabolites and amino acids, including glutamine, glutamate and aspartate. We related the magnitude of changes in the intestinal microbiota and metabolome characteristics during acclimation to those observed between populations housed in separate facilities, which differed in regards to husbandry, barrier conditions and dietary intake. The microbiome variance reported here has implications for experimental reproducibility, and as a consequence, experimental design and the interpretation of research outcomes across wide range of contexts.

Urinary metabolites as noninvasive biomarkers of gastrointestinal diseases: A clinical review

The diagnosis of gastrointestinal (GI) disorders is usually based on invasive techniques such as endoscopy. A key important factor in GI cancer is early diagnosis which warrants development of non- or less-invasive diagnostic techniques. In addition, monitoring and surveillance are other important parts in the management of GI diseases. Metabolomics studies with nuclear magnetic resonance and mass spectrometry can measure the concentration of more than 3000 chemical compounds in the urine providing possible chemical signature in different diseases and during health. In this review, we discuss the urinary metabolomics signature of different GI diseases including GI cancer and elaborate on how these biomarkers could be used for the classification, early diagnosis and the monitoring of the patients. Moreover, we discuss future directions of this still evolving field of research.

Emerging role of novel biomarkers in the diagnosis of inflammatory bowel disease

There is currently no gold standard test for the diagnosis of inflammatory bowel disease (IBD). Physicians must rely on a number of diagnostic tools including clinical and endoscopic evaluation as well as histologic, serologic and radiologic assessment. The real difficulty for physicians in both primary and secondary care is differentiating between patients suffering from functional symptoms and those with true underlying IBD. Alongside this, there is always concern regarding the possibility of a missed, or delayed diagnosis of ulcerative colitis (UC) or Crohn’s disease. Even once the diagnosis of IBD has been made, there is often uncertainty in distinguishing between cases of UC or Crohn’s. As a consequence, in cases of incorrect diagnosis, optimal treatment and management may be adversely affected. Endoscopic evaluation can be uncomfortable and inconvenient for patients. It carries significant risks including perforation and in terms of monetary cost, is expensive. The use of biomarkers to help in the diagnosis and differentiation of IBD has been increasing over time. However, there is not yet one biomarker, which is sensitive of specific enough to be used alone in diagnosing IBD. Current serum testing includes C-reactive protein and erythrocyte sedimentation rate, which are cheap, reliable but non-specific and thus not ideal. Stool based testing such as faecal calprotectin is a much more specific tool and is currently in widespread clinical use. Non-invasive sampling is of the greatest clinical value and with the recent advances in metabolomics, genetics and proteomics, there are now more tools available to develop sensitive and specific biomarkers to diagnose and differentiate between IBD. Many of these new advances are only in early stages of development but show great promise for future clinical use.

Halofuginone reduces the inflammatory responses of DSS-induced colitis through metabolic reprogramming

Halofuginone inhibits both HIF-1alpha and incomplete FAO to reduce the inflammatory response in DSS-induced colitis.

A strategy for the targeted metabolomics analysis of 11 gut microbiota-host co-metabolites in rat serum, urine and feces by ultra high performance liquid chromatography-tandem mass spectrometry

Microbiota-host co-metabolites are well-known to play important physiological roles, and their dysregulation has been found to be closely related to various diseases, including but not limited to inflammatory disorders. We developed herein an original and feasible method using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The method developed enables rapid quantification of 11 key gut microbiota-host co-metabolites spanning the succinate, phenylacetylglutamine, hippurate and trimethylamine metabolic pathways within 10 min. With this method, we were able to simultaneously monitor inflammation-induced alterations of these metabolites in rat serum, urine and feces matrices. The measured levels for this panel of endogenous metabolites ranged from 0.001 to 172.8 μg m L(-1). The intra- and inter-day precision of three analytes was less than 13.1% and the accuracy was between -13.0 to 11.2% for all QC levels. The extraction recoveries in serum ranged from 85.4 to 103.2%, while the RSD was 9.0% or less for all recoveries. In addition, extraction recoveries of 11 analytes in urine and feces samples were between 85.7% and 102.0% and RSD was less than 9.5%. The method developed here has been successfully applied to the analysis of real samples from 2,4,6-trinitrobenzenesulfonic acid-induced Crohn's disease in rats. All of these results suggest that the presently developed method is sufficiently sensitive and robust to simultaneously monitor co-metabolites with diverse properties and a range of different concentrations. Therefore, this method will be expected to be useful for comprehensive studies of the pathophysiological roles and mechanisms of these key microbiota-host co-metabolites, which reflect the function of the intestine, consequently offering novel opportunities for evaluating the occurrence, development and therapeutic effects of diseases related to microbiota disturbances.

Changes in urinary metabolic profiles of colorectal cancer patients enrolled in a prospective cohort study (ColoCare)

INTRODUCTION

Metabolomics is a valuable tool for biomarker screening of colorectal cancer (CRC). In this study, we profiled the urinary metabolomes of patients enrolled in a prospective patient cohort (ColoCare). We aimed to describe changes in the metabolome in the longer clinical follow-up and describe initial predictors as candidate markers with possibly prognostic significance.

METHODS

In total, 199 urine samples from CRC patients pre-surgery (n=97), 1-8 days post-surgery (n=12) and then after 6 and 12 months (n=52 and 38, respectively) were analyzed using both GC-MS and ¹H-NMR. Both datasets were analyzed separately with built in uni- and multivariate analyses of Metaboanalyst 2.0. Furthermore, adjusted linear mixed effects regression models were constructed.

RESULTS

Many concentrations of the metabolites derived from the gut microbiome were affected by CRC surgery, presumably indicating a tumor-induced shift in bacterial species. Associations of the microbial metabolites with disease stage indicate an important role of the gut microbiome in CRC.We were able to differentiate the metabolite profiles of CRC patients prior to surgery from those at any post-surgery timepoint using a multivariate model containing 20 marker metabolites (AUCROC=0.89; 95% CI:0.84-0.95).

CONCLUSION

To the best of our knowledge, this is one of the first metabolomic studies to follow CRC patients in a prospective setting with repeated urine sampling over time. We were able to confirm markers initially identified in case-control studies and pin point metabolites which may serve as candidates for prognostic biomarkers of CRC.

Application of metabonomics in research of inflammatory bowel disease

Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), is a chronic non-specific inflammatory disorder of the gastrointestinal tract. The etiology and pathogenesis of IBD are still not entirely understood today and are thought to be caused by the interaction of multiple factors, including environmental, genetic, infectious and immune factors. The lack of typical clinical features also leads to a difficult diagnosis of IBD. In recent years, metabonomics is becoming a very important way to find biomarkers and investigate disease mechanisms. In this paper we review the main technologies of metabonomics and their present application in IBD.

Identification of bile biomarkers of biliary tract cancer through a liquid chromatography/mass spectrometry-based metabolomic method

The incidence and mortality rate of biliary tract cancer have been increasing worldwide; however, its diagnosis and prognosis have not improved in recent years. A novel approach, termed 'metabolomics', may have the potential to be developed as an effective diagnostic tool. The present study prospectively obtained bile samples from 115 individuals, including 32 patients with biliary tract cancer, 61 patients with benign biliary tract diseases and 22 normal controls. A liquid chromatography/mass spectrometry (LC/MS)‑based approach was used to investigate the differences in bile samples between the three groups, followed by multivariate statistical analysis, which included partial least squares projection to latent structures with discriminant analysis (PLS‑DA) and orthogonal projection to latent structures with discriminant analysis (OPLS‑DA). The metabolomic 2D score plot and 3D plot revealed clear separation between the cancer, benign and normal control groups by PLS‑DA. To further address the significant difficulties in clinically differentiating between biliary tract cancer and benign biliary tract diseases, OPLS‑DA was performed to distinguish between the two disease groups and to select potential biomarkers. The cancer and benign groups were well differentiated. The metabolic analysis revealed significantly lower levels of lysophosphatidylcholine, phenylalanine, 2‑octenoylcarnitine, tryptophan and significantly higher levels of taurine‑ and glycine‑conjugated bile acids in the bile from patients with biliary tract cancer compared with those in the bile from patients with benign biliary tract disease. The present study suggested that an LC/MS‑based metabolomic investigation provides a potent and promising approach for discriminating biliary tract cancer from benign biliary tract diseases and the identified specific metabolites may offer potential as novel biomarkers for the early detection of biliary tract cancer.

Laboratory evaluation and metabolomics in inflammatory bowel disease

Diagnosis and prognosis of inflammatory bowel disease (IBD) remain a challenge for physicians, and they are often based on history, clinical symptoms and endoscopic, histological, radiological and laboratory findings. Studies have shown that metabolomics may have important value in the diagnosis and prognosis of IBD. This paper will review the latest progress in laboratory evaluation and metabolomics in IBD.

Serum metabolomics identifies citrulline as a predictor of adverse outcomes in an equine model of gut-derived sepsis

Acute laminitis is an inflammatory disease of the equine foot that often occurs secondarily to sepsis or systemic inflammation associated with gastrointestinal disease. It has been suggested that laminitis is similar to multiple organ dysfunction syndrome in humans, although in horses the weight-bearing laminar epithelium of the foot appears to be the tissue most sensitive to insult and the first "organ" to fail. Metabolomics performed on serum samples collected before (Con) and after (Lmn) experimental induction of gastrointestinal-associated sepsis in six horses detected 1,177 metabolites of both mammalian and bacterial origin in equine serum. Network and correlation analyses suggested a dysregulation of fatty acid metabolism in the Lmn group, as well as an accumulation of organic acids such as lactate. Furthermore, concentrations of the amino acid citrulline were decreased in Lmn samples from all study animals, suggesting that citrulline might be useful as a biomarker to identify critically ill animals that are at risk of developing laminitis. We therefore established normal ranges of plasma citrulline concentrations in a separate group of horses (n = 36) and tested the ability of citrulline to predict adverse outcomes (laminitis or death) in critically ill horses (n = 23). Plasma citrulline was significantly lower in critically ill horses that went on to experience adverse outcomes (n = 6). Further study is required to accurately determine a diagnostic cutoff, but the present data are suggestive of the predictive value of citrulline as a biomarker for laminar failure in equine sepsis.

Metabolomics: is it useful for inflammatory bowel diseases?

PURPOSE OF REVIEW

The assessment of metabolite profiles in biofluids has become a powerful method for the detection of biomarker molecules and disease mechanisms. This review outlines the recent advances in the use of metabolomic techniques to study inflammatory bowel diseases (IBDs).

RECENT FINDINGS

The last few years have seen an increase in the studies of experimental and human IBD focusing on the search for small metabolites, such as amino acids, bases, and tricarboxylic acid cycle intermediates. Experimental methods for the screening of metabolites in serum, urine, fecal extracts, and colon tissue include H NMR spectroscopy, gas chromatography-mass spectrometry, and liquid chromatography methods. Several studies demonstrate that IBD patients and healthy individuals, as well as the IBD subtypes, can be distinguished using metabolic profiling. Metabolomic data of fecal extracts and urine have revealed disruptions in bacterial populations, findings that are indicative of a possible involvement of the microbiome in the development of IBDs.

SUMMARY

Metabolites from biofluids can be detected in IBDs by different experimental methods that allow successful separation of IBD subtypes from healthy cohorts. Knowledge of a unique metabolomic fingerprint in IBDs could be useful for diagnosis, treatment, and detection of disease mechanisms.

Metabolomic fingerprint reveals that metformin impairs one-carbon metabolism in a manner similar to the antifolate class of chemotherapy drugs

Metabolomic fingerprint of breast cancer cells treated with the antidiabetic drug metformin revealed a significant accumulation of 5-formimino-tetrahydrofolate, one of the tetrahydrofolate forms carrying activated one-carbon units that are essential for the de novo synthesis of purines and pyrimidines. De novo synthesis of glutathione, a folate-dependent pathway interconnected with one-carbon metabolism was concomitantly depleted in response to metformin. End-product reversal studies demonstrated that thymidine alone leads to a significant but incomplete protection from metformin's cytostatic effects. The addition of the substrate hypoxanthine for the purine salvage pathway produces major rightward shifts in metformin's growth inhibition curves. Metformin treatment failed to activate the DNA repair protein ATM kinase and the metabolic tumor suppressor AMPK when thymidine and hypoxanthine were present in the extracellular milieu. Our current findings suggest for the first time that metformin can function as an antifolate chemotherapeutic agent that induces the ATM/AMPK tumor suppressor axis secondarily following the alteration of the carbon flow through the folate-related one-carbon metabolic pathways.