基于气相色谱-飞行时间质谱技术的佐剂性关节炎大鼠尿液代谢组学的研究

采用弗氏完全佐剂(FCA)诱导佐剂性关节炎(AA)大鼠模型,观察大鼠足趾肿胀度和踝关节组织的病理学形态变化。应用气相色谱-飞行时间质谱(GC-TOF MS)技术检测AA大鼠尿液代谢物谱,并对数据进行主成分分析(PCA)、偏最小二乘法-判别分析(PLS-DA)及正交偏最小二乘法-判别分析(OPLS-DA),探讨可能的发病机制。通过变量重要性投影值(VIP>1)和P值(<0.05),筛选出尿液中的差异代谢物。在模型组大鼠的尿液中共发现异柠檬酸、α-酮戊二酸、柠康酸、肌酸、3-羟基丁酸等20种差异代谢物。推断AA代谢组学的发病机制可能与能量代谢、氨基酸代谢、脂肪酸代谢途径有关。     

Nontargeted urine metabolomics analysis of the protective and therapeutic effects of Citri Reticulatae Chachiensis Pericarpium on high-fat feed-induced hyperlipidemia in rats

In this study, we focused on studying the changes in urine metabolites in hyperlipidemic rats using ultra-performance liquid chromatography coupled with quadrupole time-of-fight mass spectrometry (UPLC–Q-TOF/MS) and metabolomics, as well as the effect of Citri Reticulatae Chachiensis Pericarpium (CRCP) on hyperlipidemia. These urine samples were examined by UPLC–Q-TOF/MS to obtain MS data. The MS data were analyzed by principal component analysis and partial least squares-discriminant analysis to identify the differential metabolites. CRCP reduced the body weight and levels of triglycerides, total cholesterol and low-density lipoprotein cholesterol and abnormally decreased high-density lipoprotein cholesterol in hyperlipidemic rats, which were significantly raised by a high-fat diet. Twenty-seven potential biomarkers were identified within the complex sample matrix of urine. Fourteen biomarkers increased in the hyperlipidemia rats compared with normal rats. Meanwhile, 13 biomarkers decreased. CRCP reversed abnormal changes in biomarkers, including 5-l -glutamyl-taurine, 5-aminopentanoic acid, cis-4-octenedioic acid and 2-octenedioic acid. These biomarkers show that hyperlipidemia is related to the metabolic pathways of taurine and hypotaurine metabolism, fatty acid biosynthesis , and arginine and proline metabolism . CRCP mainly prevents hyperlipidemia by intervening in these metabolic pathways.     

Urinary metabolite profiling provides potential differentiation to explore the mechanisms of adjuvant‐induced arthritis in rats

To explore the pathogenesis of rheumatoid arthritis (RA) from the perspective of metabolomics, gas chromatography time‐of‐flight mass spectrometry (GC‐TOF/MS) technology was used to observe changes in the metabolic profiles of urine output from rats with adjuvant‐induced arthritis (AA). Sprague–Dawley rats were randomly divided into a control group and an experimental group, with eight in each. Rats in the experimental group were induced by intracutaneous innoculation of 0.1 mL Freund's complete adjuvant to right paws. On day 20 after immunization, the metabolic profiles between rat control and experimental groups were compared by combining GC‐TOF/MS technology with multivariate statistical approaches, including principal component analysis, partial least squares discriminant analysis and orthogonal projections to latent structures–discriminant analysis. Nine potential biomarkers were identified, including 2,2‐dimethylsuccinic acid, tartronic acid, dehydroshikimic acid, hippuric acid, adenine, phenaceturic acid, l ‐dopa, 1,4‐dihydroxy‐2‐naphthoic acid and melibiose. The findings indicate that the rats with AA are disturbed in metabolism of purine, amino acid, fat and energy. This study also demonstrates that the dysfunction in a range of biosynthetic and catabolic pathways, which leads to increased oxygen free radicals and inflammation, could cause underlying pathogenesis of RA. Copyright © 2016 John Wiley & Sons, Ltd.     

Metabonomics study of atherosclerosis rats by ultra fast liquid chromatography coupled with ion trap-time of flight mass spectrometry

An ultra fast liquid chromatography coupled with IT-TOF mass spectrometry (UFLC/MS-IT-TOF) metabonomic approach was employed to study the plasma and urine metabolic profiling of atherosclerosis rats. Acquired data were subjected to principal component analysis (PCA) for differentiating the atherosclerosis and the control groups. Potential biomarkers were screened by using S-plot and were identified by the accurate mass and MSⁿ fragments information obtained from UFLC/MS-IT-TOF analysis. 12 metabolites in rat plasma and 8 metabolites in urine were identified as potential biomarkers. Concentrations of leucine, phenylalanine, tryptophan, acetylcarnitine, butyrylcarnitine, propionylcarnitine and spermine in plasma and 3-O-methyl-dopa, ethyl N2-acetyl-l-argininate, leucylproline, glucuronate, t6A N(6)-(N-threonylcarbonyl)-adenosine and methyl-hippuric acid in urine decreased in atherosclerosis rats. Ursodeoxycholic acid, chenodeoxycholic acid, LPC (C16:0), LPC (C18:0) and LPC (C18:1) in plasma and hippuric acid in urine were in higher levels in atherosclerosis rats. The alterated metabolites demonstrated abnormal metabolism of phenylalanine, tryptophan, bile acids and amino acids. This research proved that metabonomics is a promising tool for disease research.     

Study of the phase I and phase II metabolism of nephrotoxin aristolochic acid by liquid chromatography/tandem mass spectrometry

Prolonged exposure to aristolochic acid (AA) was shown to pose rapid progressive renal fibrosis in Belgian women in a slimming regime in the early 1990s. AA was also demonstrated to be strong carcinogen in rats. The carcinogenicity of AA is generally believed to be related to the nitro-reduction of AA, in which the aristolactam-nitriumion ion with a delocalized positive charge is the ultimate carcinogen. In this study, the phase I and phase II metabolism of AA was investigated by using an in vitro system with rat liver S9 and an in vivo animal study with Sprague-Dawley rats. AA was found to have been undergone hydroxylation, lactam formation, and desnitro and desmethyl transformations. Three conjugated metabolites of AA, namely the N- and O-glucuronides of aristolactams, were detected directly in pre-concentrated urine sample, with no acid hydrolysis or enzymatic digestion. Structural elucidation of the metabolites was performed by using liquid chromatography/tandem mass spectrometry (LC/MS/MS). The results indicated that N-glucuronidation was the major phase II metabolic pathway for the aristolactams formed by AA after their nitro-reduction.     

Metabolic characterization of the early stage of hepatic fibrosis in rat using GC‐TOF/MS and multivariate data analyses

The aim of this study was to explore the changes in the urine metabolic spectrum in rats with the early stage of liver fibrosis using gas chromatography–time of flight/mass spectrometry (GC‐TOF/MS), try to search for potential biomarkers and elucidate the probably metabonomic pathogenesis. The early stage of liver fibrosis was established with a single subcutaneous injection of carbon tetrachloride twice each week for 4 weeks continuously. At the end of the experiment, GC‐TOF/MS technology with multivariate statistical approaches such as principal component analysis, partial least squares‐discriminant analysis and orthogonal partial least squares‐discriminant analysis was used to analyze the changes in the metabolic spectrum trajectory and identify potential biomarkers. Twelve potential biomarkers in the model group, such as succinic acid, threonine and lactose, were selected, which indicate that the metabonomic pathogenesis of the early stage of liver fibrosis may be related to disorders of energy metabolism, amino acid metabolism and fatty acid metabolism.     

Ion-pairing reversed-phase liquid chromatography/electrospray ionization mass spectrometric analysis of 76 underivatized amino acids of biological interest: a new tool for the diagnosis of inherited disorders of amino acid metabolism

Seventy-six molecules of biological interest for the diagnosis of inherited disorders of amino acids (AA) metabolism have previously been demonstrated to be detectable in electrospray ionization tandem mass spectrometry (ESI-MS/MS) positive mode without derivatization. Reversed-phase liquid chromatography (RPLC) separation on different C18 columns using various perfluorinated carboxylic acids as ion-pairing agents has been found suitable for coupling with MS/MS, and for the separation of AA. A new procedure was optimized in order to replace the usual ion-exchange chromatographic, post-column ninhydrin derivatization, time-consuming routine method. This procedure allowed an adequate separation of all the molecules from other known interfering compounds, and a throughput of two samples per hour. Quantification limits for each molecule were found to be compatible with their measurement in plasma and urine. We validated the qualitative part of the method by analyzing plasma and urine samples from patients affected with several inherited disorders of AA metabolism. We validated the quantification of 16 AA using their stable isotopes as internal standard. The calibration curves were linear over the range 0-3 mM. The quantitative results obtained with the new method on 105 plasma and 99 urine samples were in good agreement with those obtained by the established routine method. Spiking experiments and precision results were also satisfactory.     

A metabonomic analysis of urine from rats treated with rhizoma alismatis using ultra‐performance liquid chromatography/mass spectrometry

A metabonomic approach based on ultra‐performance liquid chromatography coupled to mass spectrometry (UPLC/MS) was used to study the nephrotoxicity of rhizoma alismatis (RA) in rats. Potential biomarkers of RA toxicity were identified and the toxicological mechanism is discussed. Urine samples were collected from control and treated rats at various stages and analyzed by UPLC/MS in positive ionization mode. Histopathological analysis was used to evaluate renal function. The differences in the metabolic profiles of the control and treated rats were clearly distinguishable with principal components analysis (PCA) of the chromatographic data, and significant changes in 13 metabolite biomarkers were detected in the urine. This metabonomic method combined with PCA could discriminate the treated rats from the control rats on days 60, 120, and 180 after treatment, before serious organic renal damage was apparent on day 180 with histopathology. This research indicates that UPLC/MS‐based metabonomic analysis of urine samples can be used to predict the chronic nephrotoxicity induced by rhizoma alismatis. Copyright © 2011 John Wiley & Sons, Ltd.     

Liquid chromatography/mass spectrometry for investigating the biochemical effects induced by aristolochic acid in rats: the plasma metabolome

In this study, high‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry in conjunction with chemometric methods including principal components analysis was used to investigate metabolic profiling in plasma samples from rats dosed with aristolochic acid (AA). Differentiating metabolites were identified by high‐resolution mass spectrometry and tandem mass spectrometry analyses, database searching and comparison with the analytical results of authentic standards. Several metabolites in plasma including a glucuronide conjugate, bile acids, lysophosphatidylcholines and fatty acids were detected in rats exposed to AA. To improve visualization, a z‐score plot and a cluster heat map were generated for the concentration fluctuations of the metabolites in different dosage groups. The results obtained from this study indicated that class‐specific metabolomic patterns were obviously differentiated for each metabolite in the different dosage groups of AA. Copyright © 2010 John Wiley & Sons, Ltd.     

Development of a multi-target screening analysis for 301 drugs using a QTrap liquid chromatography/tandem mass spectrometry system and automated library searching

A new multi-target screening (MTS) procedure for drugs in blood and urine for toxicological analysis has been developed using a hybrid triple-quadrupole linear ion trap mass spectrometer (QTrap) for the fast detection and identification of 301 forensically important drugs, e.g. tranquilizers (benzodiazepines), hypnotics, drugs of abuse (opiates, cocaine, amphetamines, cannabinoids), antidepressants, neuroleptics, and some cardiac drugs, in one single liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis. Samples were extracted either with liquid-liquid extraction or solid-phase extraction. A multiple reaction monitoring (MRM) as survey scan and an enhanced product ion (EPI) scan as dependent scan were performed in an information-dependent acquisition (IDA) experiment. Finally, drug identification was carried out by library search with a newly developed MS/MS library based on EPI spectra at three different collision energies in positive mode. The advantage of this newly developed method is the possibility to detect and identify 301 drugs in one single LC/MS/MS run.     

Field amplified sample injection-capillary electrophoresis-tandem mass spectrometry for the analysis of acrylamide in foodstuffs

This paper shows the applicability of capillary electrophoresis (CE) coupled to mass spectrometry (MS) for the analysis of acrylamide (AA) in foodstuffs. In order to obtain an ionisable compound amenable to be analysed by CE, acrylamide was derivatised with 2-mercaptobenzoic acid. Spectra in positive and negative modes were studied in order to select the best ionisation mode and multistep tandem mass spectrometry was used to obtain structural information. Maximum signal was observed when negative mode was used and MS/MS and MS3 were selected for quantitation and confirmation, respectively. For the separation, a fused-silica capillary of 80 cm and 50 microm I.D. and 35 mM ammonium formate/ammonia solution at pH 10 as running electrolyte were used. The applicability of field amplified sample injection (FASI) in reversed polarity was evaluated in order to decrease detection limits. The developed FASI-CE-MS/MS method provided a detection limit of 8 ng g(-1) and good linearity (r=0.999) and precision (day-to-day lower than 15%). The method has been applied to the analysis of different representative food products and the results were compared with those obtained by LC-MS/MS.     

小儿肺炎患者尿液的代谢组学初步研究

利用液相色谱-质谱联用法对小儿肺炎( Childhood pneumonia, CP)患者和健康儿童( Healthy control)的尿液进行分析,发现小儿肺炎患者尿液中的潜在标记物,为其发病机制及早期筛查提供科学依据。筛选10例小儿肺炎患者(age 47.72±2.35 months)及10例健康儿童(age 46.65±1.97 months)尿液样本,采用快速高分辨液相色谱四极杆-飞行时间质谱联用( RRLC-Q TOF/MS)技术对其尿液代谢物进行分析,通过主成分分析方法( PCA)对两组代谢物进行分类,并发现潜在生物标记物。 RRLC-Q TOF/MS检测表明,CP组和Healthy Control组尿液代谢物图谱能得到很好的区分,并鉴定了5种生物标记物,提示嘌呤代谢、氨基酸代谢可能在小儿肺炎发生发展中有重要作用。     

Discovery of safety biomarkers for realgar in rat urine using UFLC-IT-TOF/MS and 1H NMR based metabolomics

As an arsenical, realgar (As₄S₄) is known as a poison and paradoxically as a therapeutic agent. However, a complete understanding of the precise biochemical alterations accompanying the toxicity and therapy effects of realgar is lacking. Using a combined ultrafast liquid chromatography (UFLC) coupled with ion trap time-of-flight mass spectrometry (IT-TOF/MS) and ¹H NMR spectroscopy based metabolomics approach, we were able to delineate significantly altered metabolites in the urine samples of realgar-treated rats. The platform stability of the liquid chromatography LC/MS and NMR techniques was systematically investigated, and the data processing method was carefully optimized. Our results indicate significant perturbations in amino acid metabolism, citric acid cycle, choline metabolism, and porphyrin metabolism. Thirty-six metabolites were proposed as potential safety biomarkers related to disturbances caused by realgar, and glycine and serine are expected to serve as the central contacts in the metabolic pathways related to realgar-induced disturbance. The LC/MS and NMR based metabolomics approach established provided a systematic and holistic view of the biochemical effects of realgar on rats, and might be employed to investigate other drugs or xenobiotics in the future.

Mass spectrometry for the detection of differentially expressed proteins: a comparison of surface-enhanced laser desorption/ionization and capillary electrophoresis/mass spectrometry

The discovery of biomarkers is currently attracting much interest as it harbors great potential for the diagnosis and monitoring of human diseases. Here we have used two advanced mass spectroscopy based technologies, surface enhanced laser desorption ionization (SELDI-MS) and capillary electrophoresis/mass spectrometry (CE/MS), to obtain proteomic patterns of urine samples from patients suffering from membranous glomerulonephritis (MGN) and healthy volunteers. The results indicate that CE/MS analysis is able to display a rich and complex pattern of polypeptides with high resolution and high mass accuracy. In order to analyze these patterns, the MosaiqueVisu software was developed for peak identification, deconvolution and the display of refined maps in a three-dimensional format. The polypeptide profiles obtained with SELDI-MS from the same samples are much sparser and show lower resolution and mass accuracy. The SELDI-MS profiles are further heavily dependent on analyte concentration. SELDI-MS analysis identified three differentially expressed polypeptides, which are potential biomarkers that can distinguish healthy donors from patients with MGN. In contrast, approximately 200 potential biomarkers could be identified by CE/MS. Thus, while SELDI-MS is easy to use and requires very little sample, CE/MS generates much richer data sets that enable an in-depth analysis.     

Discovery of safety biomarkers for atorvastatin in rat urine using mass spectrometry based metabolomics combined with global and targeted approach

In order to develop a safety biomarker for atorvastatin, this drug was orally administrated to hyperlipidemic rats, and a metabolomic study was performed. Atorvastatin was given in doses of either 70 mg kg⁻¹ day⁻¹ or 250 mg kg⁻¹ day⁻¹ for a period of 7 days (n = 4 for each group). To evaluate any abnormal effects of the drug, physiological and plasma biochemical parameters were measured and histopathological tests were carried out. Safety biomarkers were derived by comparing these parameters and using both global and targeted metabolic profiling. Global metabolic profiling was performed using liquid chromatography/time of flight/mass spectrometry (LC/TOF/MS) with multivariate data analysis. Several safety biomarker candidates that included various steroids and amino acids were discovered as a result of global metabolic profiling, and they were also confirmed by targeted metabolic profiling using gas chromatography/mass spectrometry (GC/MS) and capillary electrophoresis/mass spectrometry (CE/MS). Serum biochemical and histopathological tests were used to detect abnormal drug reactions in the liver after repeating oral administration of atorvastatin. The metabolic differences between control and the drug-treated groups were compared using PLS-DA score plots. These results were compared with the physiological and plasma biochemical parameters and the results of a histopathological test. Estrone, cortisone, proline, cystine, 3-ureidopropionic acid and histidine were proposed as potential safety biomarkers related with the liver toxicity of atorvastatin. These results indicate that the combined application of global and targeted metabolic profiling could be a useful tool for the discovery of drug safety biomarkers.     

Metabonomics investigation of human urine after ingestion of green tea with gas chromatography/mass spectrometry, liquid chromatography/mass spectrometry and (1)H NMR spectroscopy

A method using gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS) and (1)H NMR with pattern recognition tools such as principle components analysis (PCA) was used to study the human urinary metabolic profiles after the intake of green tea. From the normalized peak areas obtained from GC/MS and LC/MS and peak heights from (1)H NMR, statistical analyses were used in the identification of potential biomarkers. Metabolic profiling by GC/MS provided a different set of quantitative signatures of metabolites that can be used to characterize the molecular changes in human urine samples. A comparison of normalized metabonomics data for selected metabolites in human urine samples in the presence of potential overlapping peaks after tea ingestion from LC/MS and (1)H NMR showed the reliability of the current approach and method of normalization. The close agreements of LC/MS with (1)H NMR data showed that the effects of ion suppression in LC/MS for early eluting metabolites were not significant. Concurrently, the specificity of detecting the stated metabolites by (1)H NMR and LC/MS was demonstrated. Our data showed that a number of metabolites involved in glucose metabolism, citric acid cycle and amino acid metabolism were affected immediately after the intake of green tea. The proposed approach provided a more comprehensive picture of the metabolic changes after intake of green tea in human urine. The multiple analytical approach together with pattern recognition tools is a useful platform to study metabolic profiles after ingestion of botanicals and medicinal plants.     

Simultaneous quantification of vortioxetine,fluoxetine and their metabolites in rat plasma by UPLC–MS/MS

In this study, a specific and quick ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) method was fully developed and validated for simultaneous measurement of the rat plasma levels of vortioxetine (VOR), Lu AA34443 (the major metabolite of VOR), fluoxetine and its metabolite norfluoxetine with diazepam as the internal standard (IS). After a simple protein precipitation with acetonitrile for sample preparation, the separation of the analytes were performed on an Acquity UPLC BEH C18 (2.1 × 50 mm, 1.7 μm) column, with acetonitrile and 0.1% formic acid in water as mobile phase by gradient elution. The detection was achieved on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring mode via an electrospray ionization source. Good linearity was observed in the calibration curve for each analyte. The data of precision, accuracy, matrix effect, recovery and stability all conformed to the bioanalytical method validation of acceptance criteria of US Food and Drug Administration recommendations. The newly developed UPLC–MS/MS method allowed simultaneous quantification of VOR, fluoxetine and their metabolites for the first time and was successfully applied to a pharmacokinetic study in rats.     

Analytical validation and clinical application of urinary vanillylmandelic acid and homovanillic acid by LC–MS/MS for diagnosis of neuroblastoma

Vanillylmandelic acid (VMA) and homovanillic acid (HVA) are clinical biomarkers for diagnosis of neuroblastoma (NB), which commonly occurs in the childhood. Development and application of a robust LC–MS/MS method for fast determination of these biomarkers for optimal laboratory testing of NB is essential in clinical laboratories. In present study, we developed and validated a simple liquid chromatography tandem mass spectrometry (LC–MS/MS) method for quick clinical testing of VMA and HVA for diagnosis of NB. The method was validated according to the current CLSI C62‐A and FDA guidelines. The age‐adjusted pediatric reference intervals and diagnostic performance were evaluated in both 24 h urine and random urine. Injection‐to‐injection time was 3.5 min. Inter‐ and intra‐assay coefficients of variation (CVs) were ≤3.88%. The lower limit of quantification and the limit of detection were 0.50 and 0.25 μmol/L for both VMA and HVA. Recoveries of VMA and HVA were in the ranges of 85–109% and 86–100% with CVs ≤5.76%. This method was free from significant matrix effect, carryover and interference. The establishment of age‐adjusted pediatric reference intervals by this LC–MS/MS method was favorable for the improvement in diagnostic performance, which was crucial for correct interpretation of test results from children in both 24 h and random urine.     

Structural Elucidation of in vivo and in vitro Metabolites of Epiberberine in Rat and Its Liver and Intestines by Liquid Chromatography-Tandem Mass Spectrometry

The in vivo and in vitro metabolism of epiberberine was investigated using a highly specific and sensitive liquid chromatography–mass spectrometry (LC–MS/MS) method. In vivo samples including rat urine, feces, and plasma samples were collected individually after ingestion of 35 mg/kg epiberberine to healthy rats. In vitro samples were prepared by incubating epiberberine with homogenized liver and intestinal flora of rats, respectively. As a result, at least 17, 3 and 5 metabolites were found in rat urine, feces, and plasma, respectively. Additionally, 1 and 3 metabolites were found in the rat intestinal flora and homogenized liver incubation mixtures, respectively.     

Therapeutic Effects of Selaginella tamariscina on the Model of Acute Gout with Hyperuricemia in Rats Based on Metabolomics Analysis

Gout is a disease of purine metabolic disorders which results from long‐term hyperuricemia and the sodium urate deposition in and around the joints. Selaginella tamariscina (ST ) is an important traditional Chinese herbal medicine and is used for the treatment of gout and hyperuricemia. In this study, the rat model of acute gout with hyperuricemia was established by intraperitoneal injection of xanthine and oxonic acid potassium salt and articular injection monosodium urate (MSU ). The effect of ST in the treatment of gout was investigated by measuring joint swelling, the expression of IL ‐1β in serum and histological changes of joint by haematoxylin eosin (H&E) staining. Subsequently, urine metabolomics analysis for biomarkers discovery in acute gout with hyperuricemia rats was performed by the ultra‐performance liquid chromatography‐electrospray ionization quadruple time‐of‐flight mass spectrometry (UPLC‐ESI‐QTOF /MS ) combined with chemometric approach. Principal component analysis (PCA ) and orthogonal partial least squares‐discriminant analysis (OPLS‐DA ) were used to detect potential biomarkers. A total of 18 potential biomarkers were identified mainly including tryptophan metabolism; tyrosine metabolism; lysine methylation; pyrimidine metabolism; purine metabolism; TCA cycle and fatty acid metabolisms. This study indicates that ST could efficiently ameliorate the disease of acute gout with hyperuricemia in rats. The related metabolic biomarkers could provide useful information and the metabolic mechanism could be used for further study about the model of acute gout with hyperuricemia in rats.