NMR spectroscopy based metabonomic studies on the comparative biochemistry of the kidney and urine of the bank vole (Clethrionomys glareolus), wood mouse (Apodemus sylvaticus), white toothed shrew (Crocidura suaveolens) and the laboratory rat

Standardizing and increasing the utility of lipidomics: a look to the next decade

Introduction: We present our views on the current application of mass spectrometry (MS) based lipidomics and how lipidomics can develop in the next decade to be most practical use to society. That is not to say that lipidomics has not already been of value. In-fact, in its earlier guise as metabolite profiling most of the pathways of steroid biosynthesis were uncovered and via focused lipidomics many inborn errors of metabolism are routinely clinically identified. However, can lipidomics be extended to improve biochemical understanding of, and to diagnose, the most prevalent diseases of the 21^st century? Areas covered: We will highlight the concept of 'level of identification' and the equally crucial topic of 'quantification'. Only by using a standardized language for these terms can lipidomics be translated to fields beyond academia. We will remind the lipid scientist of the value of chemical derivatization, a concept exploited since the dawn of lipid biochemistry. Expert opinion: Only by agreement of the concepts of identification and quantification and their incorporation in lipidomics reporting can lipidomics maximize its value.

Danggui Buxue Tang restores antibiotic-induced metabolic disorders by remodeling the gut microbiota

ETHNOPHARMACOLOGICAL RELEVANCE

Danggui Buxue Tang (DBT) has been used to promote hematopoiesis and relieve myelosuppression in China. Antibiotics can cause myelosuppression through gut microbiota disorders.

AIM OF THE STUDY

This study aims to explore the way of DBT to alleviate the metabolic disorder caused by antibiotics.

MATERIALS AND METHODS

In this study, 16S rRNA sequencing was used to detect the change of gut microbiota, metabolomics to analyze the change of metabolites. Correlation analysis was used to establishment the correlation between gut microbiota and metabolites. PICRUST 2 was used to predict the function of gut microbiota.

RESULTS

Results showed that eighty-two genera of gut microbiota were affected by antibiotic, while twelve were significantly restored after DBT. Seventy-four potential metabolites were significantly different from the antibiotics and DBT. We found significant recovery by the Bacteroides and Rikenellaceae RC9 after DBT. The metabolic pathways influenced by the antibiotic treatment included primary and secondary bile biosynthesis, etc. The metabolic pathways that could be restored after DBT included the primary and secondary bile acid biosynthesis pathway, etc. Through correlation analysis, we found a correlation between the Bacteroides, Rikenellaceae_RC9_gut_group and other potential differential metabolisms such as those of taurodeoxycholic acid, N-phenylacetyl glycine, etc. The functional prediction showed that the biosynthesis of primary bile acid, secondary bile acid was significantly affected.

CONCLUSIONS

DBT can restore the gut and reverse the metabolic disorder caused by antibiotics through Bacteroides, and it provides a new medical idea regarding the gut microbiota balance.

NMR Spectroscopy for Metabolomics Research

Over the past two decades, nuclear magnetic resonance (NMR) has emerged as one of the three principal analytical techniques used in metabolomics (the other two being gas chromatography coupled to mass spectrometry (GC-MS) and liquid chromatography coupled with single-stage mass spectrometry (LC-MS)). The relative ease of sample preparation, the ability to quantify metabolite levels, the high level of experimental reproducibility, and the inherently nondestructive nature of NMR spectroscopy have made it the preferred platform for long-term or large-scale clinical metabolomic studies. These advantages, however, are often outweighed by the fact that most other analytical techniques, including both LC-MS and GC-MS, are inherently more sensitive than NMR, with lower limits of detection typically being 10 to 100 times better. This review is intended to introduce readers to the field of NMR-based metabolomics and to highlight both the advantages and disadvantages of NMR spectroscopy for metabolomic studies. It will also explore some of the unique strengths of NMR-based metabolomics, particularly with regard to isotope selection/detection, mixture deconvolution via 2D spectroscopy, automation, and the ability to noninvasively analyze native tissue specimens. Finally, this review will highlight a number of emerging NMR techniques and technologies that are being used to strengthen its utility and overcome its inherent limitations in metabolomic applications.

Intervening Effects of Total Alkaloids of Corydalis saxicola Bunting on Rats With Antibiotic-Induced Gut Microbiota Dysbiosis Based on 16S rRNA Gene Sequencing and Untargeted Metabolomics Analyses

Gut microbiota dysbiosis induced by antibiotics is strongly connected with health concerns. Studying the mechanisms underlying antibiotic-induced gut microbiota dysbiosis could help to identify effective drugs and prevent many serious diseases. In this study, in rats with antibiotic-induced gut microbiota dysbiosis treated with total alkaloids of Corydalis saxicola Bunting (TACS), urinary and fecal biochemical changes and cecum microbial diversity were investigated using 16S rRNA gene sequencing analysis and untargeted metabolomics. The microbial diversity results showed that 10 genera were disturbed by the antibiotic treatment, and two of them were obviously restored by TACS. The untargeted metabolomics analysis identified 34 potential biomarkers in urine and feces that may be the metabolites that are most related to the mechanisms underlying antibiotic-induced gut microbiota dysbiosis and the therapeutic effects of TACS treatment. The biomarkers were involved in six metabolic pathways, comprising pathways related to branched-chain amino acid (BCAA), bile acid, arginine and proline, purine, aromatic amino acid, and amino sugar and nucleotide sugar metabolism. Notably, there was a strong correlation between these metabolic pathways and two gut microbiota genera (g__Blautia and g__Intestinibacter). The correlation analysis suggested that TACS might synergistically affect four of these metabolic pathways (BCAA, bile acid, arginine and proline, and purine metabolism), thereby modulating gut microbiota dysbiosis. Furthermore, we performed a molecular docking analysis involving simulating high-precision docking and using molecular pathway maps to illuminate the way that ligands (the five main alkaloid components of TACS) act on a complex molecular network, using CYP27A1 (a key enzyme in the bile acid synthesis pathway) as the target protein. This study provides a comprehensive overview of the intervening effects of TACS on the host metabolic phenotype and gut microbiome in rats with gut microbiota dysbiosis, and it presents new insights for the discovery of effective drugs and the best therapeutic approaches.

A review of the pharmaceutical exposome in aquatic fauna

Pharmaceuticals have been considered 'contaminants of emerging concern' for more than 20 years. In that time, many laboratory studies have sought to identify hazard and assess risk in the aquatic environment, whilst field studies have searched for targeted candidates and occurrence trends using advanced analytical techniques. However, a lack of a systematic approach to the detection and quantification of pharmaceuticals has provided a fragmented literature of serendipitous approaches. Evaluation of the extent of the risk for the plethora of human and veterinary pharmaceuticals available requires the reliable measurement of trace levels of contaminants across different environmental compartments (water, sediment, biota - of which biota has been largely neglected). The focus on pharmaceutical concentrations in surface waters and other exposure media have therefore limited both the characterisation of the exposome in aquatic wildlife and the understanding of cause and effect relationships. Here, we compile the current analytical approaches and available occurrence and accumulation data in biota to review the current state of research in the field. Our analysis provides evidence in support of the 'Matthew Effect' and raises critical questions about the use of targeted analyte lists for biomonitoring. We provide six recommendations to stimulate and improve future research avenues.

Investigation of Dioscorea bulbifera Rhizome-Induced Hepatotoxicity in Rats by a Multisample Integrated Metabolomics Approach

The use of herbal medicines continues to expand globally, meanwhile, herb-associated hepatotoxicity is becoming a safety issue. As a conventional Chinese medicinal herb, Dioscorea bulbifera rhizome (DBR) has been documented to cause hepatic toxicity. However, the exact underlying mechanism remains largely unexplored. In the present study, we aimed to profile entire endogenous metabolites in a biological system using a multisample integrated metabolomics strategy. Our findings offered additional insights into the molecular mechanism of the DBR-induced hepatotoxicity. We identified different metabolites from rat plasma, urine, and feces by employing gas chromatography-mass spectrometry in combination with multivariate analysis. In total, 55 metabolites distributed in 33 metabolic pathways were identified as being significantly altered in DBR-treated rats. Correlation network analysis revealed that the hub metabolites of hepatotoxicity were mainly associated with amino acid, bile acid, purine, pyrimidine, lipid, and energy metabolism. As such, DBR affected the physiological and biological functions of liver via the regulation of multiple metabolic pathways to an abnormal state. Notably, our findings also demonstrated that the multisample integrated metabolomics strategy has a great potential to identify more biomarkers and pathways in order to elucidate the mechanistic complexity of toxicity of traditional Chinese medicine.

NMR and MS Methods for Metabolomics

Metabolomics, also often referred as "metabolic profiling," is the systematic profiling of metabolites in biofluids or tissues of organisms and their temporal changes. In the last decade, metabolomics has become more and more popular in drug development, molecular medicine, and other biotechnology fields, since it profiles directly the phenotype and changes thereof in contrast to other "-omics" technologies. The increasing popularity of metabolomics has been possible only due to the enormous development in the technology and bioinformatics fields. In particular, the analytical technologies supporting metabolomics, i.e., NMR, UPLC-MS, and GC-MS, have evolved into sensitive and highly reproducible platforms allowing the determination of hundreds of metabolites in parallel. This chapter describes the best practices of metabolomics as seen today. All important steps of metabolic profiling in drug development and molecular medicine are described in great detail, starting from sample preparation to determining the measurement details of all analytical platforms, and finally to discussing the corresponding specific steps of data analysis.

NMR-based metabolic characterization of chicken tissues and biofluids: a model for avian research

INTRODUCTION

Poultry is one of the most consumed meat in the world and its related industry is always looking for ways to improve animal welfare and productivity. It is therefore essential to understand the metabolic response of the chicken to new feed formulas, various supplements, infections and treatments.

OBJECTIVES

As a basis for future research investigating the impact of diet and infections on chicken's metabolism, we established a high-resolution proton nuclear magnetic resonance (NMR)-based metabolic atlas of the healthy chicken (Gallus gallus).

METHODS

Metabolic extractions were performed prior to 1H-NMR and 2D NMR spectra acquisition on twelve biological matrices: liver, kidney, spleen, plasma, egg yolk and white, colon, caecum, faecal water, ileum, pectoral muscle and brain of 6 chickens. Metabolic profiles were then exhaustively characterized.

RESULTS

Nearly 80 metabolites were identified. A cross-comparison of these matrices was performed to determine metabolic variations between and within each section and highlighted that only eight core metabolites were systematically found in every matrice.

CONCLUSION

This work constitutes a database for future NMR-based metabolomic investigations in relation to avian production and health.

The strengths and weaknesses of NMR spectroscopy and mass spectrometry with particular focus on metabolomics research

Mass spectrometry (MS) and nuclear magnetic resonance (NMR) have evolved as the most common techniques in metabolomics studies, and each brings its own advantages and limitations. Unlike MS spectrometry, NMR spectroscopy is quantitative and does not require extra steps for sample preparation, such as separation or derivatization. Although the sensitivity of NMR spectroscopy has increased enormously and improvements continue to emerge steadily, this remains a weak point for NMR compared with MS. MS-based metabolomics provides an excellent approach that can offer a combined sensitivity and selectivity platform for metabolomics research. Moreover, different MS approaches such as different ionization techniques and mass analyzer technology can be used in order to increase the number of metabolites that can be detected. In this chapter, the advantages, limitations, strengths, and weaknesses of NMR and MS as tools applicable to metabolomics research are highlighted.

Integrated plasma and urine metabolomics coupled with HPLC/QTOF-MS and chemometric analysis on potential biomarkers in liver injury and hepatoprotective effects of Er-Zhi-Wan

Metabolomics techniques are the comprehensive assessment of endogenous metabolites in a biological system and may provide additional insight into the molecular mechanisms. Er-Zhi-Wan (EZW) is a traditional Chinese medicine formula, which contains Fructus Ligustri Lucidi (FLL) and Herba Ecliptae (HE). EZW is widely used to prevent and treat various liver injuries through the nourishment of the liver. However, the precise molecular mechanism of hepatoprotective effects has not been comprehensively explored. Here, an integrated metabolomics strategy was designed to assess the effects and possible mechanisms of EZW against carbon tetrachloride-induced liver injury, a commonly used model of both acute and chronic liver intoxication. High-performance chromatography/quadrupole time-of-flight mass spectrometry (HPLC/QTOF-MS) combined with chemometric approaches including principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to discover differentiating metabolites in metabolomics data of rat plasma and urine. Results indicate six differentiating metabolites, tryptophan, sphinganine, tetrahydrocorticosterone, pipecolic acid, L-2-amino-3-oxobutanoic acid and phosphoribosyl pyrophosphate, in the positive mode. Functional pathway analysis revealed that the alterations in these metabolites were associated with tryptophan metabolism, sphingolipid metabolism, steroid hormone biosynthesis, lysine degradation, glycine, serine and threonine metabolism, and pentose phosphate pathway. Of note, EZW has a potential pharmacological effect, which might be through regulating multiple perturbed pathways to the normal state. Our findings also showed that the robust integrated metabolomics techniques are promising for identifying more biomarkers and pathways and helping to clarify the function mechanisms of traditional Chinese medicine.

Analysis of the restorative effect of Bu-zhong-yi-qi-tang in the spleen-qi deficiency rat model using (1)H-NMR-based metabonomics

ETHNOPHARMACOLOGICAL RELEVANCE

Bu-zhong-yi-qi-tang (BT) is a classical formula for the treatment of spleen-qi descending, visceroptosis with hyposplenic qi, uterine prolapse, and rectal prolapse due to chronic diarrhea in traditional Chinese medicine (TCM) and has been identified as an effective drug for the treatment of TCM spleen-qi deficiency in clinical practice. The present study aimed to investigate the restorative effect and the potential mechanisms of Bu-zhong-yi-qi-tang in a rat spleen-qi deficiency model using (1)H-NMR-based metabonomics.

MATERIALS AND METHODS

The rat spleen-qi deficiency model was established as follows: oral administration of Radix Rhei extract (equivalent to 10g/kg body weight of the crude drug), loaded swimming, and starvation for 24h. Each of these treatments was administered consecutively every three days. Sixty male SD rats were randomly divided into five groups, and three of the groups received a different oral dose of the aqueous extract of Bu-zhong-yi-qi-tang during the last seven days of the three-week experimental period. The body weight and motor behavior of the rats were measured and recorded once a week. The endogenous metabolites in the plasma were analyzed using NMR in conjunction with multivariate and statistical techniques. In addition, the liver and spleen were removed and weighed.

RESULTS

All of the rats in the spleen-qi deficiency group presented pasty loose stools, inactiveness, grouping, a decrease in swimming endurance, and lackluster, loose, and disorderly behavior in addition to a significant decrease in body weight, spleen weight, and liver weight. In contrast, the abovementioned demonstrations were reversed to a certain extent in the rats treated with Bu-zhong-yi-qi-tang compared with the model group (p<0.05, p<0.01). A significant separation was determined between the control and model groups in the PCA score plot, which indicates that the spleen-qi deficiency model was successfully duplicated. The changes in the levels of endogenous metabolites in the plasma included lower levels of valine, leucine, and O-acetyl-glycoprotein and a higher concentration of lactate in the spleen-qi deficiency group compared with the control group. Treatment with Bu-zhong-yi-qi-tang at least partially returned the levels of these metabolites to the normal levels.

CONCLUSIONS

The restorative effects of Bu-zhong-yi-qi-tang in rats with spleen-qi deficiency were confirmed, and four endogenous metabolites were identified as potential biomarkers of the symptoms of spleen-qi deficiency and most likely play roles in the changes observed in certain metabolic pathways, such as the energy, protein, and glycolytic metabolisms.

Differential metabolic responses of clam Ruditapes philippinarum to Vibrio anguillarum and Vibrio splendidus challenges

Clam Ruditapes philippinarum is one of the important marine aquaculture species in North China. However, pathogens can often cause diseases and lead to massive mortalities and economic losses of clam. In this work, we compared the metabolic responses induced by Vibrio anguillarum and Vibrio splendidus challenges towards hepatopancreas of clam using NMR-based metabolomics. Metabolic responses suggested that both V. anguillarum and V. splendidus induced disturbances in energy metabolism and osmotic regulation, oxidative and immune stresses with different mechanisms, as indicated by correspondingly differential metabolic biomarkers (e.g., amino acids, ATP, glucose, glycogen, taurine, betaine, choline and hypotaurine) and altered mRNA expression levels of related genes including ATP synthase, ATPase, glutathione peroxidase, heat shock protein 90, defensin and lysozyme. However, V. anguillarum caused more severe oxidative and immune stresses in clam hepatopancreas than V. splendidus. Our results indicated that metabolomics could be used to elucidate the biological effects of pathogens to the marine clam R. philippinarum.

Metabonomics Combined with UPLC-MS Chemical Profile for Discovery of Antidepressant Ingredients of a Traditional Chinese Medicines Formula, Chaihu-Shu-Gan-San

This study proposed a new strategy for uncovering the active chemical constituents of a traditional Chinese medicines (TCMs) formula, Chaihu-Shu-Gan-San (CSGS). Metabonomics and chemical profile were integrated in combination with the multivariate statistical analysis (MVA) to discover the chemical constituents which contribute to the antidepressant effect of CSGS. Based upon the difference between CSGS and QZ (CSGS without Zhi-Qiao) extracts in the chemical profiles and the regulations of metabolic disturbances induced by CUMS, synephrine, naringin, hesperidin, and neohesperidin were recognized as the active constituents of CSGS from Zhi-qiao responsible for those missing regulations of CSGS when Zhi-Qiao was subtracted from the whole formula. They participated in the regulations of the deviated metabolites 2-4, 10-14, and 22-25, involved in metabolic pathways of ketone bodies synthesis, phenylalanine, tyrosine and tryptophan biosynthesis, valine, aspartate, glutamate metabolism, and glycolysis/gluconeogenesis. Furthermore, the assay of MAO-A activity confirmed the potential antidepressant effect of naringin and its active sites on the MAO-A was inferred by molecular docking study. The integration of metabonomics and chemical profile was proved to be a useful strategy for uncovering what the active chemical constituents in TCM formula are and how they make contributions for the efficacy of the formula.

Metabolomic study of plasma from female mink (Neovison vison) with low and high residual feed intake during restrictive and ad libitum feeding

Metabolite profiling may elucidate changes in metabolic pathways under various physiological or nutritional conditions. In the present study two groups of female mink characterised as having a high (16 mink) or low (14 mink) residual feed intake were investigated during restrictive and ad libitum feeding. Blood samples were collected three times during the experimental period; during restrictive feeding, and four days and three weeks after the change to ad libitum feeding. Plasma samples were subjected to liquid chromatography mass spectrometry non-targeted metabolomics. Subjecting data to principal component analysis showed that there was no grouping of the data according to the residual feed intake. In contrast, data were clearly grouped according to feeding level. Identification of the metabolites responsible for this grouping showed that the plasma level of metabolites related to mobilisation of energy was high during restrictive feeding, e.g. betaine, carnitine, and creatine. During ad libitum feeding the plasma level of metabolites that can be characterised as biomarkers of meat intake (creatinine, carnosine, 1- and 3 methylhistidine) was high. The plasma level of lysophosphatidylcholine species was highest after four days of ad libitum feeding suggesting a short term imbalance in the transport or metabolism of these metabolites when changing the feeding level.

Application of ex vivo (1)H NMR metabonomics to the characterization and possible detection of renal cell carcinoma metastases

PURPOSE

Renal cell carcinoma (RCC) is the most prevalent malignancy of the kidney. Its survival rates are very low since most of patients develop metastases beyond the kidney at the time of diagnosis. Early detection is currently by far the most promising approach to reduce RCC mortality. Metabolic alterations have been suggested to have a crucial role in cancer development. Metabonomics can present a holistic picture of the metabolites alterations and provide biomarkers that could revolutionize disease characterization and detection.

METHODS

Ex vivo (1)H NMR spectra of tumors and the paired adjacent tissues obtained from living patients with RCC were recorded and analyzed using multivariate statistical techniques combined with quantitative statistical analyses.

RESULTS

In the present study, we showed that the metabonomes of RCC, either with or without metastases, differ markedly from those of their adjacent tissues. Besides, the RCC patients with metastases can be distinctly differentiated from those without metastases. Metabolic perturbations arising from malignant transformations were also systematically characterized. Compared to the adjacent tissues, RCC tumors had elevated levels of lactate, glutamate, pyruvate, glutamine, and creatine, but decreased levels of acetate, malate, and amino acids including valine, alanine, and aspartate.

CONCLUSIONS

Systemic changes in metabolite concentrations are most likely the result of cells switching to glycolysis to maintain energy homeostasis. The results suggest that metabonomics may also facilitate the discovery of novel cancer biomarkers and allows the stratification of tumors under different pathophysiological conditions, which might be a valuable future tool for RCC detection and possibly other cancers.

Metabolic responses in gills of Manila clam Ruditapes philippinarum exposed to copper using NMR-based metabolomics

Copper is an important heavy metal contaminant with high ecological risk in the Bohai Sea. In this study, the metabolic responses in the bioindicator, Manila clam (Ruditapes philippinarum), to the environmentally relevant copper exposures were characterized using NMR-based metabolomics. The significant metabolic changes corresponding to copper exposures were related to osmolytes, intermediates of the Krebs cycle and amino acids, such as the increase in homarine, branched chain amino acids and decrease in succinate, alanine and dimethylamine in the copper-exposed clam gills during 96 h exposure period. Overall, Cu may lead to the disturbances in osmotic regulation and energy metabolism in clams during 96 h experimental period. These results demonstrate that NMR-based metabolomics is applicable for the discovery of metabolic biomarkers which could be used to elucidate the toxicological mechanisms of marine heavy metal contaminants.

Metabolomics, pathway regulation, and pathway discovery

Metabolomics is a data-based research strategy, the aims of which are to identify biomarker pictures of metabolic systems and metabolic perturbations and to formulate hypotheses to be tested. It involves the assay by mass spectrometry or NMR of many metabolites present in the biological system investigated. In this minireview, we outline studies in which metabolomics led to useful biomarkers of metabolic processes. We also illustrate how the discovery potential of metabolomics is enhanced by associating it with stable isotopic techniques.

Tissue-specific toxicological effects of cadmium in green mussels (Perna viridis): nuclear magnetic resonance-based metabolomics study

Toxicity tests for metals have traditionally focused on selected biomarkers to characterize the biological stress induced by metals in marine organisms. Here nuclear magnetic resonance (NMR)-based metabolomics, a system biology tool, was applied to the marine green mussel, Perna viridis, to investigate the toxicological effects of Cd in both digestive gland and adductor muscle tissues. After Cd exposure for either two or four weeks, there was no significant metabolic change in the mussels exposed to Cd at 2 µg/L. At 20 µg/L, there were major metabolite changes related to amino acids, osmolytes, and energy metabolites. Digestive gland tissue was more sensitive to Cd than adductor muscle tissue. The adductor muscle tissue showed elevated levels of glutamine, glutamate, and lactate, and reduced levels of branched chain amino acids, aspartate, phenylalanine, and tyrosine. Overall, four weeks of Cd exposure produced neurotoxicity and metabolic disturbances and disturbed osmoregulation. These results suggest that the adductor muscle tissue of mussels may be a suitable supplemental biomarker for exposure to toxicants. In addition, the results demonstrate that (1) H-NMR-based metabolomic analysis can provide a systematic view of the toxicological effects of metals on mussels, suggesting that it might be employed to investigate the toxicological effects of other marine pollutants.

Urinary metabonomics study of anti-depressive effect of Chaihu-Shu-Gan-San on an experimental model of depression induced by chronic variable stress in rats

Chaihu-Shu-Gan-San (CSGS), a traditional Chinese medicine (TCM) formula, has been effectively used for the treatment of depression in clinic. However, studies of its anti-depressive mechanism are challenging, accounted for the complex pathophysiology of depression, and complexity of CSGS with multiple constituents acting on different metabolic pathways. The variations of endogenous metabolites in rat model of depression after administration of CSGS may offer deeper insights into the anti-depressive effect and mechanism of CSGS. In this study, metabonomics based on ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) was used to profile the metabolic fingerprints of urine obtained from chronic variable stress (CVS)-induced depression model in rats with and without CSGS treatment. Through partial least squares-discriminate analysis, it was observed that metabolic perturbations induced by chronic variable stress were restored in a time-dependent pattern after treatment with CSGS. Metabolites with significant changes induced by CVS, including 3-O-methyldopa (1), pantothenic acid (2), kynurenic acid (3), xanthurenic acid (4), 2,8-dihydroxyquinoline glucuronide (5), 5-hydroxy-6-methoxyindole glucurnoide (8), l-phenylalanyl-l-hydroxyproline (9), indole-3-carboxylic acid (10), proline (11), and the unidentified metabolites (6, 2.11min_m/z 217.0940; 7, 2.11min_m/z 144.0799), were characterized as potential biomarkers involved in the pathogenesis of depression. The derivations of all those biomarkers can be regulated by CSGS treatment except indole-3-carboxylic acid (10), which suggested that the therapeutic effect of CSGS on depression may involve in regulating the dysfunctions of energy metabolism, tryptophan metabolism, bone loss and liver detoxification. This study indicated that the rapid and noninvasive urinary metabonomics approach may be a powerful tool to study the efficacy and mechanism of complex TCM prescriptions.

NMR and MS methods for metabonomics

Metabonomics, also often referred to as "metabolomics" or "metabolic profiling," is the systematic profiling of metabolites in bio-fluids or tissues of organisms and their temporal changes. In the last decade, metabonomics has become increasingly popular in drug development, molecular medicine, and other biotechnology fields, since it profiles directly the phenotype and changes thereof in contrast to other "-omics" technologies. The increasing popularity of metabonomics has been possible only due to the enormous development in the technology and bioinformatics fields. In particular, the analytical technologies supporting metabonomics, i.e., NMR, LC-MS, UPLC-MS, and GC-MS have evolved into sensitive and highly reproducible platforms allowing the determination of hundreds of metabolites in parallel. This chapter describes the best practices of metabonomics as seen today. All important steps of metabolic profiling in drug development and molecular medicine are described in great detail, starting from sample preparation, to determining the measurement details of all analytical platforms, and finally, to discussing the corresponding specific steps of data analysis.

An optimized procedure for metabonomic analysis of rat liver tissue using gas chromatography/time-of-flight mass spectrometry

In this paper, we present a tissue metabonomic method with an optimized extraction procedure followed by instrumental analysis with gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) and spectral data analysis with multivariate statistics. Metabolite extractions were carried out using three solvents: chloroform, methanol, and water, with design of experiment (DOE) theory and multivariate statistical analysis. A two-step metabolite extraction procedure was optimized using a mixed solvent of chloroform-methanol-water (1:2:1, v/v/v) and then followed by methanol alone. This approach was subsequently validated using standard compounds and liver tissues. Calibration curves were obtained in the range of 0.50-125.0mug/mL for standards and 0.02-0.25g/mL acceptable for liver tissue samples. For most of the metabolites investigated, relative standard deviations (RSD) were below 10% within a day (reproducibility) and below 15% within a week (stability). Rat liver tissues of carbon tetrachloride-induced acute liver injury models (n=10) and healthy control rats (n=10) were analyzed which demonstrated the applicability of the developed procedure for the tissue metabonomic study.

1H NMR metabolomics study of age profiling in children

Metabolic profiling of urine provides a fingerprint of personalized endogenous metabolite markers that correlate to a number of factors such as gender, disease, diet, toxicity, medication, and age. It is important to study these factors individually, if possible to unravel their unique contributions. In this study, age-related metabolic changes in children of age 12 years and below were analyzed by (1)H NMR spectroscopy of urine. The effect of age on the urinary metabolite profile was observed as a distinct age-dependent clustering even from the unsupervised principal component analysis. Further analysis, using partial least squares with orthogonal signal correction regression with respect to age, resulted in the identification of an age-related metabolic profile. Metabolites that correlated with age included creatinine, creatine, glycine, betaine/TMAO, citrate, succinate, and acetone. Although creatinine increased with age, all the other metabolites decreased. These results may be potentially useful in assessing the biological age (as opposed to chronological) of young humans as well as in providing a deeper understanding of the confounding factors in the application of metabolomics.

Experimental estimation of postmortem interval using multivariate analysis of proton NMR metabolomic data

Nuclear magnetic resonance (NMR) spectroscopy has recently been applied to metabolic studies. In particular, metabolic profiles of tissues or of the whole body can easily be acquired through multivariate analysis of NMR spectra. The present study investigates metabolic changes after death in rat femoral muscles using pattern recognition of proton NMR spectra. Rats were killed by suffocation, cocaine overdose and induced respiratory failure, and then low molecular weight metabolites extracted using perchlorate from excised tissues were measured using proton NMR. All spectral data were processed and assessed by multivariate analysis to obtain metabolic profiles of the tissues. The results of principal component analysis (PCA) score plots soon after death showed that the metabolic profiles of the tissues differed according to the mode of death. The principal component (PC) scores of the data varied hourly and correlated with postmortem interval. The present results showed that NMR-based metabolic profiling could provide useful information with which to estimate postmortem intervals and causes of death.

Metabonomic study of biochemical changes in the serum of type 2 diabetes mellitus patients after the treatment of metformin hydrochloride

A metabonomic study on biochemical changes in the serum of type 2 diabetes mellitus patients after the treatment of metformin hydrochloride was performed. (1)H NMR and UPLC/MS were used to generate metabolic fingerprints for the metabonomic analysis of serum samples obtained from 20 type 2 diabetes mellitus patients without any drugs treatment and 15 type 2 diabetes mellitus patients treated with metformin hydrochloride for 3 months. The resulting data were subjected to chemometric analysis (principal component analysis and partial least squares discriminant analysis) to investigate the effect of metformin hydrochloride on serum metabolite profiles of type 2 diabetes mellitus patients. (1)H NMR spectroscopic analysis revealed increased trimethylamine-N-oxide (TMAO), 3-hydroxybutyrate (3-HB) and decreased glucose, N-acetyl glycoprotein (NAC), lipoprotein, lactate, acetoacetate and unsaturated lipids in serum from metformin treated patients compared to untreated ones. UPLC/MS in positive electrospray ionization detected increased tryptophan and decreased lysophosphatidylcholines (C16:0 LPC, C18:0 LPC and C18:2 LPC) as well as phenylalanine in treated group. Both analytical techniques used in this study were able to detect biochemical changes in the serum of type 2 diabetes mellitus patients after the treatment of metformin hydrochloride, which may be helpful to the understanding of action mechanism of metformin hydrochloride.

Environmental metabolomics using 1H-NMR spectroscopy

Environmental metabolomics is a subdiscipline of metabolomics and focuses on the study of metabolic changes in organisms in response to environmental challenges. This approach is ideal for studying multiple species within an ecosystem because it is not dependent on knowledge of an organism's genome. Unbiased measurements of an organism's metabolic composition can in principle be used to identify novel biomarker profiles and modes of action of stressors. This chapter presents protocols for the extraction of metabolites from biological samples, the measurement of metabolites using 1H nuclear magnetic resonance (NMR) spectroscopy, and finally the analysis of the metabolic data using multivariate statistical methods. First, the preparation of biofluids (e.g., blood and urine) for NMR analysis is described together with a methanol-chloroform protocol for extracting metabolites from tissue samples. Next the NMR methods are presented, comprising a standard one-dimensional (1-D) 1H-NMR method and a two-dimensional (2-D) 1H-1H J-resolved NMR experiment. The advantages and limitations of each method are discussed. Finally, two methods for analyzing the multivariate metabolic NMR data are presented. These include a traditional fingerprinting approach that comprises of a spectral preprocessing step followed by multivariate statistical analysis. Although reliable and proven, this method often produces results in terms of unidentified metabolites that are of limited value to the biologist. The second and newer method is based on metabolic profiling in which NMR spectra are deconvoluted into a list of metabolites and their concentrations. Although more biologically insightful, this latter approach can prove labor intensive.

Liquid chromatography and ultra-performance liquid chromatography-mass spectrometry fingerprinting of human urine: sample stability under different handling and storage conditions for metabonomics studies

Typically following collection biological samples are kept in a freezer for periods ranging from a few days to several months before analysis. Experience has shown that in LC-MS-based metabonomics research the best analytical practice is to store samples as these are collected, complete the sample set and analyse it in a single run. However, this approach is prudent only if the samples stored in the refrigerator or in the freezer are stable. Another important issue is the stability of the samples following the freeze-thaw process. To investigate these matters urine samples were collected from 6 male volunteers and analysed by LC-MS and ultra-performance liquid chromatography (UPLC)-MS [in both positive and negative electrospray ionization (ESI)] on the day of collection or at intervals of up to 6 months storage at -20 degrees C and -80 degrees C. Other sets of these samples underwent a series of up to nine freeze-thaw cycles. The stability of samples kept at 4 degrees C in an autosampler for up to 6 days was also assessed, with clear differences appearing after 48h. Data was analysed using multivariate statistical analysis (principal component analysis). The results show that sample storage at both -20 and -80 degrees C appeared to ensure sample stability. Similarly up to nine freeze thaw cycles were without any apparent effect on the profile.

Comparison of histological, genetic, metabolomics, and lipid-based methods for sex determination in marine mussels

Omics technologies are increasingly being used to monitor organismal responses to environmental stressors. Previous studies have shown that species identification, an appreciation of life history traits, and organism phenotype (e.g., gender) are essential for the accurate interpretation of omics data from field samples. As marine mussels are increasingly being used in ecotoxicogenomics and monitoring, a technique to determine mussel gender throughout their annual reproductive cycle is urgently needed. This study examines four methods for sex determination in the two mussel species found in the United Kingdom, Mytilus edulis and Mytilus galloprovincialis, and their hybrid. Each of these methods-histology, a lipid-based assay, a new reverse transcriptase polymerase chain reaction (RT-PCR) assay, and nuclear magnetic resonance (NMR)-based metabolomics-initially was evaluated using sexually mature ("ripe") mussels whose gender was clearly distinguishable using histology. The methods subsequently were tested on spawned ("spent") mussels. For ripe animals, all techniques yielded high classification accuracies: histology, 100%; RT-PCR, 94.6%; lipid analysis, 90.6%; and metabolomics, 89.5%. The gender of spent animals, however, could not be determined by histology (0%) or lipid analysis (55.6%), but RT-PCR (100%) and metabolomics (88.9%) both proved to be successful. In addition, the RT-PCR, metabolomics, and lipid-based methods identified animals of mixed sex. Our findings highlight the application of a novel RT-PCR method as a robust technique for gender determination of ripe and spent mussels.

1H NMR study of the effects of sample contamination in the metabolomic analysis of mouse urine

Nuclear magnetic resonance (NMR) spectroscopy was used to evaluate and optimize the strategy for collecting mouse urine samples. A series of normal urine samples and those mixed with folate-deficient food, turkey or mouse fecal particles were analyzed using principal component analysis (PCA). The metabolic profile of urine mixed with folate-deficient food was found to be extremely different than that of clean urine. Changes in the urine composition caused by mixing with turkey or feces are relatively small as judged by the output of PCA. As a result, turkey may be considered as an applicable food source for obtaining uncontaminated urine samples for metabolomics-based research.

Metabolomic and genetic analysis of biomarkers for peroxisome proliferator-activated receptor alpha expression and activation

Peroxisome proliferator-activated receptor alpha (PPARalpha) is a nuclear receptor with manifold effects on intermediary metabolism. To define a set of urinary biomarkers that could be used to determine the efficacy of PPARalpha agonists, a metabolomic investigation was undertaken in wild-type and Pparalpha-null mice fed for 2 wk either a regular diet or a diet containing the PPARalpha ligand Wy-14,643 ([4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio] acetic acid), and their urine was analyzed by ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry. Principal components analysis of 6393 accurate mass positive ions revealed clustering as a single phenotype of the treated and untreated Pparalpha (-/-) mice plus two additional discrete phenotypes for the treated and untreated Pparalpha (+/+) mice. Biomarkers of PPARalpha activation were identified from their accurate masses and confirmed by tandem mass spectrometry of authentic compounds. Biomarkers were quantitated from raw chromatographic data using appropriate calibration curves. PPARalpha urinary biomarkers highly statistically significantly elevated by Wy-14,643 treatment included 11beta-hydroxy-3,20-dioxopregn-4-en-21-oic acid (>3700-fold), 11beta,20-dihydroxy-3-oxopregn-4-en-21-oic acid (50-fold), nicotinamide (>2-fold), nicotinamide 1-oxide (5-fold), 1-methylnicotinamide (1.5-fold), hippuric acid (2-fold), and 2,8-dihydroxyquinoline-beta-d-glucuronide (3-fold). PPARalpha urinary biomarkers highly statistically significantly attenuated by Wy-14,643 treatment included xanthurenic acid (1.3-fold), hexanoylglycine (20-fold), phenylpropionylglycine (4-fold), and cinnamoylglycine (9-fold). These biomarkers arise from PPARalpha effects on tryptophan, corticosterone, and fatty acid metabolism and on glucuronidation. This study underscores the power of mass spectrometry-based metabolomics combined with genetically modified mice in the definition of monogenic metabolic phenotypes.

Metabolic profiling of serum from gadolinium chloride-treated rats by 1H NMR spectroscopy

Metabolic profiling of serum from gadolinium chloride (GdCl(3), 10 and 50 mg/kg body weight, intraperitoneal [i.p.])-treated rats was investigated by the NMR spectroscopic-based metabonomic strategy. Serum samples were collected at 48, 96, and 168h postdose (p.d.) after exposure to GdCl(3). (1)H NMR spectra of serum were analyzed by pattern recognition using principal components analysis. The studies showed that there was a dose-related biochemical effect of GdCl(3) treatment on the levels of a range of low-molecular weight compounds in serum. The liver damage induced by GdCl(3) was characterized by the elevation of lactate, pyruvate, and creatine as well as the decrease of branched-chain amino acids (valine and isoleucine), alanine, glucose, and trimethylamine-N-oxide concentration in serum samples. The biochemical effects of GdCl(3) in rats could be consulted when evaluating the biochemical profile of gadolinium-containing compounds that are being developed for nuclear magnetic resonance imaging.

Metabonomics in pharmaceutical discovery and development

Metabonomics has emerged as a key technology in pharmaceutical discovery and development, evolving as the small molecule counterpart of transcriptomics and proteomics. In drug discovery laboratories, metabonomics aids in target identification, phenotyping, and the understanding of the biochemical basis of disease and toxicity. This review focuses on three areas where metabonomics is used in the industry: (1) analytical considerations, (2) chemometric and statistical concerns, and (3) biological aspects and applications.

Capillary electrophoresis-mass spectrometry for metabolomics

A new approach for the comprehensive and quantitative analysis of charged metabolites by capillary electrophoresis-mass spectrometry (CE-MS) is described. Metabolites are first separated by CE based on charge and size, and then selectively detected using MS by monitoring ions over a large range of m/z values. This technique enables the simultaneous determination of over 1000 charged species, and it can readily be applied to various types of biological samples originating from bacteria, plants, mammals, body fluids, and others. This chapter highlights detailed practical procedures for using this technology.

The comparative metabonomics of age-related changes in the urinary composition of male Wistar-derived and Zucker (fa/fa) obese rats

The global metabolite profiles of endogenous compounds excreted in urine by male Wistar-derived and Zucker (fa/fa) obese rats were investigated from 4 to 20 weeks of age using both 1H NMR spectroscopy and HPLC-TOF/MS with electrospray ionisation (ESI). Multivariate data analysis was then performed on the resulting data which showed that the composition of the samples changed with age, enabling age-related metabolic trajectories to be constructed. At 4 weeks it was possible to observe differences between the urinary metabolite profiles from the two strains, with the difference becoming more pronounced over time resulting in a marked divergence in their metabolic trajectories at 8-10 weeks. The changes in metabolite profiles detected using 1H NMR spectroscopy included increased protein and glucose combined with reduced taurine concentrations in the urine of the Zucker animals compared to the Wistar-derived strain. In the case of HPLC-MS a number of ions were found to be present at increased levels in the urine of 20 week old Zucker rats compared to Wistar-derived rats including m/z 71.0204, 111.0054, 115.0019, 133.0167 and 149.0454 (negative ion ESI) and m/z 97.0764 and 162.1147 (positive ion ESI). Conversely, ions m/z 101.026 and 173.085 (negative ion ESI) and m/z 187.144 and 215.103 (positive ion ESI) were present in decreased amounts in urine from Zucker compared to Wistar-derived rats. Metabolite identities proposed for these ions include fumarate, maleate, furoic acid, ribose, suberic acid, carnitine and pyrimidine nucleoside. The utility of applying metabonomics to understanding disease processes and the biological relevance of some of the findings are discussed.

NMR spectroscopic-based metabonomic investigation on the acute biochemical effects induced by Ce(NO3)3 in rats

An integrated metabonomic approach based on high-resolution (1)H NMR spectroscopy has been applied to the investigation of the acute biochemical effects caused by Ce(NO(3))(3) in rats. Male Wistar rats were separated into 8 groups and each was treated with one of following compounds, mercury II chloride (HgCl(2)), 2-bromoethanamine hydrobromide (BEA), carbon tetrachloride (CCl(4)), alpha-naphthylisothiocyanate (ANIT), and three doses of Ce(NO(3))(3) (i.p. 2, 10 and 50mg/kg body weight). Urine was collected over a 48-h time course, and serum and tissue samples (liver and kidney) were gained after exposure to Ce(NO(3))(3) for 48 h. Histopathology and plasma clinical chemistry were also performed for all the tissue and plasma samples. Urine and serum samples were analyzed by 600 MHz (1)H NMR spectroscopy. All the (1)H NMR spectra were data-processed and analyzed using principal components analysis or hierarchical clustering analysis to show the time- and dose-dependent biochemical variations induced by Ce(NO(3))(3). Metabolic profiles of urinary (1)H NMR spectra from animals treated with Ce(NO(3))(3) exhibited an increase in trimethylamine N-oxide (TMAO), dimethylamine (DMA), dimethylglycine (DMG), taurine (Tau) and amino acids (valine, leucine and isoleucine), together with a decrease in citrate. The (1)H NMR spectral analysis of serum presented the elevation of acetone, acetoacetate, lactate and creatinine levels. These findings indicated the impairment of fatty acid beta-oxidation in liver mitochondria and renal lesions. This work illustrates the high reliability of NMR-based metabonomic approach on the study of the biochemical effects induced by rare earths.

Metabonomic modeling of drug toxicity

Global metabolic profiling (metabonomics/metabolomics) has shown particular promise in the area of toxicology and drug development. In both preclinical screening and mechanistic exploration, metabolic profiling can offer rapid, noninvasive toxicological information that is robust and reproducible, with little or no added technical resources to existing studies in drug metabolism and toxicity. In this review, the study design and analytical technology required for metabonomics are discussed, along with key examples of how fundamental questions in drug development can be addressed. Strategies for metabonomic data analysis in toxicity assessment are detailed in both principle and practice, together with a description of toxicologically relevant metabolic biomarkers. Extended into the assessment of efficacy and toxicity in the clinic, metabonomics may prove crucial in making personalized therapy and pharmacogenomics a reality.

Comparative metabonomics of differential hydrazine toxicity in the rat and mouse

Interspecies variation between rats and mice has been studied for hydrazine toxicity using a novel metabonomics approach. Hydrazine hydrochloride was administered to male Sprague-Dawley rats (30 mg/kg, n = 10 and 90 mg/kg, n = 10) and male B6C3F mice (100 mg/kg, n = 8 and 250 mg/kg, n = 8) by oral gavage. In each species, the high dose was selected to produce the major histopathologic effect, hepatocellular lipid accumulation. Urine samples were collected at sequential time points up to 168 h post dose and analyzed by 1H NMR spectroscopy. The metabolites of hydrazine, namely diacetyl hydrazine and 1,4,5,6-tetrahydro-6-oxo-3-pyridazine carboxylic acid (THOPC), were detected in both the rat and mouse urine samples. Monoacetyl hydrazine was detected only in urine samples from the rat and its absence in the urine of the mouse was attributed to a higher activity of N-acetyl transferases in the mouse compared with the rat. Differential metabolic effects observed between the two species included elevated urinary beta-alanine, 3-D-hydroxybutyrate, citrulline, N-acetylcitrulline, and reduced trimethylamine-N-oxide excretion unique to the rat. Metabolic principal component (PC) trajectories highlighted the greater degree of toxic response in the rat. A data scaling method, scaled to maximum aligned and reduced trajectories (SMART) analysis, was used to remove the differences between the metabolic starting positions of the rat and mouse and varying magnitudes of effect, to facilitate comparison of the response geometries between the rat and mouse. Mice followed "biphasic" open PC trajectories, with incomplete recovery 7 days after dosing, whereas rats followed closed "hairpin" time profiles, indicating functional reversibility. The greater magnitude of metabolic effects observed in the rat was supported by the more pronounced effect on liver pathology in the rat when compared with the mouse.

NMR-based metabonomic approaches for evaluating physiological influences on biofluid composition

Strategies such as genomics, proteomics and metabonomics are being applied with increasing frequency in the pharmaceutical industry. For each of these approaches, toxicological response can be measured by terms of deviation from control or baseline status. However, in order to accurately define drug-induced response, it is necessary to characterize the normal degree of physiological variation in the absence of stimuli. Here, 1H NMR spectroscopic-based analyses of the metabolic composition of urine in experimental animals under various normal physiological conditions are reviewed. In particular, the effects of inter-animal and diurnal variation, gender, age, diet, species, strain, hormonal status and stress on the biochemical composition of urine are explored. Pattern recognition methods facilitate the comparison of urine NMR spectra over a given time-course, enabling the establishment of changes in profile and highlighting the dynamic metabolic status of an organism. Thus metabonomic approaches based on information-rich spectroscopic data sets can be used to evaluate normal physiological variation and for investigation of drug safety issues.

Acute biochemical effects of La(NO3)3 on liver and kidney tissues by magic-angle spinning 1H nuclear magnetic resonance spectroscopy and pattern recognition

High-resolution magic-angle spinning (MAS) 1H nuclear magnetic resonance (NMR) spectroscopic and pattern recognition (PR) based methods have been applied to studies on the acute biochemical effects of La(NO3)3 on rats. Male Wistar rats were treated with various doses of La(NO3)3 (2, 10, and 50 mg/kg body weight), and MAS 1H NMR spectra of their intact liver and kidney tissues were analyzed using principal components analysis to extract metabolic information. The biochemical effects of La(NO3)3 were characterized by the increase of triglyceride and bile acid and the decrease of glycogen in liver tissue, together with a slight elevation of triglyceride level in kidney tissue. The target lesion of La(NO3)3 to liver was found by MAS NMR-PR methods. This study illustrated the power of the combination of MAS 1H NMR and pattern recognition for the analysis of biochemical effects of rare earths.

Measuring the metabolome: current analytical technologies

The post-genomics era has brought with it ever increasing demands to observe and characterise variation within biological systems. This variation has been studied at the genomic (gene function), proteomic (protein regulation) and the metabolomic (small molecular weight metabolite) levels. Whilst genomics and proteomics are generally studied using microarrays (genomics) and 2D-gels or mass spectrometry (proteomics), the technique of choice is less obvious in the area of metabolomics. Much work has been published employing mass spectrometry, NMR spectroscopy and vibrational spectroscopic techniques, amongst others, for the study of variations within the metabolome in many animal, plant and microbial systems. This review discusses the advantages and disadvantages of each technique, putting the current status of the field of metabolomics in context, and providing examples of applications for each technique employed.

Metabonomics in Toxicology: A Review

Metabonomics and its many pseudonyms (metabolomics, metabolic profiling, etc.) have exploded onto the scientific scene in the past 2 to 3 years. Nowhere has the impact been more profound than within the toxicology community. Within this community there exists a great deal of uncertainty about whether metabonomics is something to count on or just the most recent technological flash in the pan. Much of the uncertainty is due to unfamiliarity with analytical and chemometric facets of the technology and the attendant fear of any "black-box." With those fears in mind, metabonomics technology is reviewed with particular emphasis on toxicologic applications in preclinical drug development. The jargon, logistics, and applications of the technology are covered in some detail with emphasis on recent work in the field.

Environmental metabonomics: applying combination biomarker analysis in earthworms at a metal contaminated site

Earthworms were taken across an environmental gradient of metal contamination for ecotoxicology assessment. Both indigenous (Lumbricus rubellus and L. terrestris) and introduced earthworms (Eisenia andrei, exposed in mesh bags) were studied. Changes in the levels of small molecule metabolites in earthworm tissue extracts were analysed by 1H NMR spectroscopy as a means of identifying combination biomarker compounds. Principal components analysis of the NMR spectral data revealed that biochemical changes were induced across the metal contamination gradient. Native worms (L. rubellus) from the most polluted sites were associated with an increase in the relative concentration of maltose; a decrease was also seen in the concentration of an as yet unidentified biomarker compound. Introduced worms (E. andrei) did not show differences to the same extent. Direct integration of the resonances from histidine and 1-methylhistidine showed that relative histidine concentrations were elevated slightly for L. rubellus, confirming the results of earlier mesocosm studies. Conversely, the relative concentrations of both histidine and 1-methylhistidine were greatly reduced by metal contamination in L. terrestris. This study demonstrates the utility of NMR spectroscopy in detecting previously unknown potential biomarkers for ecotoxicity testing and identified maltose as a potential biomarker compound deserving of further study.

Metabonomics technologies and their applications in physiological monitoring, drug safety assessment and disease diagnosis

In this review, metabonomics, a combination of data-rich analytical chemical measurements and chemometrics for profiling metabolism in complex systems, is described and its applications are reviewed. Metabonomics is typically carried out using biofluids or tissue samples. The relevance of the technique is reviewed in relation to other '-omics', and it is shown how the methods can be applied to physiological evaluation, drug safety assessment, characterization of genetically modified animal models of disease, diagnosis of human disease, and drug therapy monitoring. The different types of analytical data, mainly from nuclear magnetic resonance spectroscopy and mass spectrometry, are summarized. The outputs from a metabonomics study allow sample classification, for example according to phenotype, drug safety or disease diagnosis, and interpretation of the reasons for classification yields information on combination biomarkers of effect. Transcriptomic and metabonomic data is currently being further integrated into a holistic understanding of systems biology. An assessment of the possible future role and impact of metabonomics is presented.