1H-NMR spectroscopy combined with pattern recognition analysis reveals characteristic chemical patterns in urines of MS patients and non-human primates with MS-like disease

Metabolomics as a promising tool for improving understanding of multiple sclerosis: A review of recent advances

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system that usually affects young adults. The development of MS is closely related to the changes in the metabolome. Metabolomics studies have been performed using biofluids or tissue samples from rodent models and human patients to reveal metabolic alterations associated with MS progression. This review aims to provide an overview of the applications of metabolomics that for the investigations of the perturbed metabolic pathways in MS and to reveal the potential of metabolomics in personalizing treatments. In conclusion, informative variations of metabolites can be potential biomarkers in advancing our understanding of MS pathogenesis for MS diagnosis, predicting the progression of the disease, and estimating drug effects. Metabolomics will be a promising technique for improving clinical care in MS.

Contribution of Metabolomics to Multiple Sclerosis Diagnosis, Prognosis and Treatment

Metabolomics-based technologies map in vivo biochemical changes that may be used as early indicators of pathological abnormalities prior to the development of clinical symptoms in neurological conditions. Metabolomics may also reveal biochemical pathways implicated in tissue dysfunction and damage and thus assist in the development of novel targeted therapeutics for neuroinflammation and neurodegeneration. Metabolomics holds promise as a non-invasive, high-throughput and cost-effective tool for early diagnosis, follow-up and monitoring of treatment response in multiple sclerosis (MS), in combination with clinical and imaging measures. In this review, we offer evidence in support of the potential of metabolomics as a biomarker and drug discovery tool in MS. We also use pathway analysis of metabolites that are described as potential biomarkers in the literature of MS biofluids to identify the most promising molecules and upstream regulators, and show novel, still unexplored metabolic pathways, whose investigation may open novel avenues of research.

An emerging potential of metabolomics in multiple sclerosis: a comprehensive overview

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the nervous system that primarily affects young adults. Although the exact etiology of the disease remains obscure, it is clear that alterations in the metabolome contribute to this process. As such, defining a reliable and disease-specific metabolome has tremendous potential as a diagnostic and therapeutic strategy for MS. Here, we provide an overview of studies aimed at identifying the role of metabolomics in MS. These offer new insights into disease pathophysiology and the contributions of metabolic pathways to this process, identify unique markers indicative of treatment responses, and demonstrate the therapeutic effects of drug-like metabolites in cellular and animal models of MS. By and large, the commonly perturbed pathways in MS and its preclinical model include lipid metabolism involving alpha-linoleic acid pathway, nucleotide metabolism, amino acid metabolism, tricarboxylic acid cycle, d-ornithine and d-arginine pathways with collective role in signaling and energy supply. The metabolomics studies suggest that metabolic profiling of MS patient samples may uncover biomarkers that will advance our understanding of disease pathogenesis and progression, reduce delays and mistakes in diagnosis, monitor the course of disease, and detect better drug targets, all of which will improve early therapeutic interventions and improve evaluation of response to these treatments.

Higher fish consumption and lower risk of central nervous system demyelination

BACKGROUND/OBJECTIVES

The evidence for diet as a risk factor for multiple sclerosis (MS) is inconclusive. We examined the associations between fish consumption and risk of a first clinical diagnosis of central nervous system demyelination (FCD), a common precursor to MS.

METHODS

The 2003-2006 Ausimmune Study was a case-control study examining environmental risk factors for FCD, with participants recruited from four regions of Australia and matched on age, sex, and study region. Dietary intake data were collected using a food frequency questionnaire. We used conditional logistic regression models to test associations between fish consumption (total, tinned, grilled, and fried) and risk of FCD (249 cases and 438 controls), adjusting for history of infectious mononucleosis, smoking, serum 25-hydroxyvitamin D concentrations, socio-economic status, omega-3 supplement use, dietary under-reporting, and total energy intake.

RESULTS

Higher total fish consumption (per 30 g/day, equivalent to two serves/week) was associated with an 18% reduced risk of FCD (AOR 0.82; 95% CI 0.70, 0.97). While we found no statistically significant associations between grilled and fried fish consumption and risk of FCD, higher tinned fish consumption (per 30 g/day) was associated with a 41% reduced risk of FCD (AOR 0.59; 95% CI 0.39, 0.89).

CONCLUSIONS

Tinned fish is predominantly oily, whereas grilled and fried fish are likely to be a combination of oily and white types. Oily fish is high in vitamin D and very long chain polyunsaturated omega-3 fatty acids, both of which may be beneficial in relation to MS.

Experimental autoimmune encephalomyelitis in the common marmoset: a translationally relevant model for the cause and course of multiple sclerosis

Aging Western societies are facing an increasing prevalence of chronic autoimmune-mediated inflammatory disorders (AIMIDs) for which treatments that are safe and effective are scarce. One of the main reasons for this situation is the lack of animal models, which accurately replicate clinical and pathological aspects of the human diseases. One important AIMID is the neuroinflammatory disease multiple sclerosis (MS), for which the mouse experimental autoimmune encephalomyelitis (EAE) model has been frequently used in preclinical research. Despite some successes, there is a long list of experimental treatments that have failed to reproduce promising effects observed in murine EAE models when they were tested in the clinic. This frustrating situation indicates a wide validity gap between mouse EAE and MS. This monography describes the development of an EAE model in nonhuman primates, which may help to bridge the gap.

Metabolomics-based discovery of a metabolite that enhances oligodendrocyte maturation

Endogenous metabolites play essential roles in the regulation of cellular identity and activity. Here we have investigated the process of oligodendrocyte precursor cell (OPC) differentiation, a process that becomes limiting during progressive stages of demyelinating diseases, including multiple sclerosis, using mass-spectrometry-based metabolomics. Levels of taurine, an aminosulfonic acid possessing pleotropic biological activities and broad tissue distribution properties, were found to be significantly elevated (∼20-fold) during the course of oligodendrocyte differentiation and maturation. When added exogenously at physiologically relevant concentrations, taurine was found to dramatically enhance the processes of drug-induced in vitro OPC differentiation and maturation. Mechanism of action studies suggest that the oligodendrocyte-differentiation-enhancing activities of taurine are driven primarily by its ability to directly increase available serine pools, which serve as the initial building block required for the synthesis of the glycosphingolipid components of myelin that define the functional oligodendrocyte cell state.

Pattern recognition analysis of proton nuclear magnetic resonance spectra of postmortem cerebrospinal fluid from rats with drug-induced seizure or coma

Cerebrospinal fluid (CSF) is routinely subjected to gross evaluation in postmortem investigations; however, its use in chemical evaluations has not been fully realized. Analysis of nuclear magnetic resonance (NMR) spectra with pattern recognition methods was applied to CSF samples. Rats were treated with pentylenetetrazol (PTZ) to induce seizure or pentobarbital (PB) to induce coma, and postmortem CSF was collected after CO₂ gas euthanization. Pattern recognition analysis of the NMR data was performed on individual postmortem CSF samples. The aim of this study was to determine if pattern recognition analysis of NMR data could be used to classify the rats according to their drug treatment. The applicability of NMR data with pattern recognition analysis using postmortem CSF was also assessed. Partial Least Squares-Discriminant Analysis (PLS-DA) score plots indicated that the PTZ, PB, and NS (control) groups were clustered and clearly separated. PLS-DA correlation loading plots showed respective spectral and category variances of 41% and 42% for factor 1, and 17% and 27% for factor 2. Thus, factors 1 and 2 together described 58% (41%+17%) and 69% (42%+27%) of the variation, respectively. NMR study of postmortem CSF has the potential to be utilized as both a novel forensic neurochemistry method and in the clinical setting.

An Evaluation of 20 Years of EU Framework Programme-Funded Immune-Mediated Inflammatory Translational Research in Non-Human Primates

Aging western societies are facing an increasing prevalence of chronic inflammatory and degenerative diseases for which often no effective treatments exist, resulting in increasing health-care expenditure. Despite high investments in drug development, the number of promising new drug candidates decreases. We propose that preclinical research in non-human primates can help to bridge the gap between drug discovery and drug prescription. Translational research covers various stages of drug development of which preclinical efficacy tests in valid animal models is usually the last stage. Preclinical research in non-human primates may be essential in the evaluation of new drugs or therapies when a relevant rodent model is not available. Non-human primate models for life-threatening or severely debilitating diseases in humans are available at the Biomedical Primate Research Centre (BPRC). These have been instrumental in translational research for several decades. In order to stimulate European health research and innovation from bench to bedside, the European Commission has invested heavily in access to non-human primate research for more than 20 years. BPRC has hosted European users in a series of transnational access programs covering a wide range of research areas with the common theme being immune-mediated inflammatory disorders. We present an overview of the results and give an account of the studies performed as part of European Union Framework Programme (EU FP)-funded translational non-human primate research performed at the BPRC. These data illustrate the value of translational non-human primate research for the development of new therapies and emphasize the importance of EU FP funding in drug development.

Determination of Grade and Receptor Status from the Primary Breast Lesion by Magnetic Resonance Spectroscopy

Magnetic resonance spectra (MRS) from fine needle aspiration biopsies (FNAB) from primary breast lesions were analysed using a pattern recognition method, Statistical Classification Strategy, to assess tumor grade and oestrogen receptor (ER) and progesterone receptor (PgR) status. Grade 1 and 2 breast cancers were separated from grade 3 cancers with a sensitivity and specificity of 96% and 95%, respectively. The ER status was predicted with a sensitivity of 91% and a specificity of 90%, and the PgR status with a sensitivity of 91% and a specificity of 86%. These classifiers provide rapid and reliable, computerized information and may offer an objective method for determining these prognostic indicators simultaneously with the diagnosis of primary pathology and lymph node involvement.

A type 2 biomarker separates relapsing-remitting from secondary progressive multiple sclerosis

OBJECTIVE

We tested whether it is possible to differentiate relapsing-remitting (RR) from secondary progressive (SP) disease stages in patients with multiple sclerosis (MS) using a combination of nuclear magnetic resonance (NMR) metabolomics and partial least squares discriminant analysis (PLS-DA) of biofluids, which makes no assumptions on the underlying mechanisms of disease.

METHODS

Serum samples were obtained from patients with primary progressive MS (PPMS), SPMS, and RRMS; patients with other neurodegenerative conditions; and age-matched controls. Samples were analyzed by NMR and PLS-DA models were derived to separate disease groups.

RESULTS

The PLS-DA models for serum samples from patients with MS enabled reliable differentiation between RRMS and SPMS. This approach also identified significant differences between the metabolite profiles of each of the MS groups (PP, SP, and RR) and the healthy controls, as well as predicting disease group membership with high specificity and sensitivity.

CONCLUSIONS

NMR metabolomics analysis of serum is a sensitive and robust method for differentiating between different stages of MS, yielding diagnostic markers without a priori knowledge of disease pathogenesis. Critically, this study identified and validated a type II biomarker for the RR to SP transition in patients with MS. This approach may be of considerable benefit in categorizing patients for treatment and as an outcome measure in future clinical trials.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that serum metabolite profiles accurately distinguish patients with different subtypes and stages of MS.

Looking back into the future: 30 years of metabolomics at TNO

Metabolites have played an essential role in our understanding of life, health, and disease for thousands of years. This domain became much more important after the concept of metabolism was discovered. In the 1950s, mass spectrometry was coupled to chromatography and made the technique more application-oriented and allowed the development of new profiling technologies. Since 1980, TNO has performed system-based metabolic profiling of body fluids, and combined with pattern recognition has led to many discoveries and contributed to the field known as metabolomics and systems biology. This review describes the development of related concepts and applications at TNO in the biomedical, pharmaceutical, nutritional, and microbiological fields, and provides an outlook for the future.

Preclinical (1)H-MRS neurochemical profiling in neurological and psychiatric disorders

The ongoing development of animal models of neurological and psychiatric disorders in combination with the development of advanced nuclear magnetic resonance (NMR) techniques and instrumentation has led to increased use of in vivo proton NMR spectroscopy ((1)H-MRS) for neurochemical analyses. (1)H-MRS is one of only a few analytical methods that can assay in vivo and longitudinal neurochemical changes associated with neurological and psychiatric diseases, with the added advantage of being a technique that can be utilized in both preclinical and clinical studies. In this review, recent progress in the use of (1)H-MRS to investigate animal models of neurological and psychiatric disorders is summarized with examples from the literature and our own work.

Measurement of dietary exposure: a challenging problem which may be overcome thanks to metabolomics?

The diet is an important environmental exposure, and its measurement is an essential component of much health-related research. However, conventional tools for measuring dietary exposure have significant limitations being subject to an unknown degree of misreporting and dependent upon food composition tables to allow estimation of intakes of energy, nutrients and non-nutrient food constituents. In addition, such tools may be inappropriate for use with certain groups of people. As an alternative approach, the recent techniques of metabolite profiling or fingerprinting, which allows simultaneous monitoring of multiple and dynamic components of biological fluids, may provide metabolic signals indicative of food intake. Samples can be analysed through numerous analytical platforms, followed by multivariate data analysis. In humans, metabolomics has been applied successfully in pharmacology, toxicology and medical screening, but nutritional metabolomics is still in its infancy. Biomarkers of a small number of specific foods and nutrients have been developed successfully but less targeted and more high-throughput methods, that do not need prior knowledge of which signals might be discriminatory, and which may allow a more global characterisation of dietary intake, remain to be tested. A proof a principle project (the MEDE Study) is currently underway in our laboratories to test the hypothesis that high-throughput, non-targeted metabolite fingerprinting using flow injection electrospray mass spectrometry can be applied to human biofluids (blood and urine) to characterise dietary exposure in humans.

Urinary metabolic profiles of inflammatory bowel disease in interleukin-10 gene-deficient mice

Inflammatory bowel disease (IBD) is a chronic debilitating disorder that is thought to have both genetic and environmental contributors. Commensal microflora have been shown to play a key part in the disease process. Metabolomics, the study of large numbers of small molecule metabolites, has demonstrated that disease and/or changes in gut microbial composition modulate mammalian urine metabolite fingerprints. The aim of this project was to associate the development of IBD with specific changes in a mouse urinary metabolic fingerprint. Interleukin-10 (IL-10) gene-deficient mice were raised alongside age-matched 129/SvEv controls in conventional housing. Urine samples (22 h) were collected at ages 4, 6, 8, 12, 16, and 20 weeks. Metabolite concentrations were derived from analysis of nuclear magnetic resonance spectra, and both multivariate and two-way analysis of variance (ANOVA) statistical techniques were applied to the resulting data. Principal component analysis and partial least-squares-discriminant analysis of urine derived from the control and IL-10 gene-deficient mice revealed that while both groups initially had similar metabolic profiles, they diverged substantially with the onset of IBD as assessed through external phenotypic changes. Several metabolites, including trimethylamine (TMA) and fucose, changed dramatically in the IL-10 gene-deficient mice following 8 weeks of age, concomitant with the known timeline for development of severe histological injury. This study illustrates that metabolomics is effective at distinguishing IBD using urinary metabolite profiles.

Gender-dependent progression of systemic metabolic states in early childhood

Little is known about the human intra-individual metabolic profile changes over an extended period of time. Here, we introduce a novel concept suggesting that children even at a very young age can be categorized in terms of metabolic state as they advance in development. The hidden Markov models were used as a method for discovering the underlying progression in the metabolic state. We applied the methodology to study metabolic trajectories in children between birth and 4 years of age, based on a series of samples selected from a large birth cohort study. We found multiple previously unknown age- and gender-related metabolome changes of potential medical significance. Specifically, we found that the major developmental state differences between girls and boys are attributed to sphingolipids. In addition, we demonstrated the feasibility of state-based alignment of personal metabolic trajectories. We show that children have different development rates at the level of metabolome and thus the state-based approach may be advantageous when applying metabolome profiling in search of markers for subtle (patho)physiological changes.

Gender-related and age-related urinalysis of healthy subjects by NMR-based metabonomics

NMR-based metabonomic analysis is a well-established approach to characterizing healthy and diseased states. The aim of this study was to investigate inter-individual variability in the metabolic urinary profile of a healthy Greek population, not subjected to strict dietary limitations, by NMR-based metabonomics. The overall metabonomic urinalysis showed a homogeneous distribution among the population. The metabolic profile was examined in relation to gender and age, and reference intervals of major metabolites were determined. Multivariate data analysis led to the construction of two robust models that were able to predict the class membership of the subjects studied according to their gender and age. The most influential low molecular weight metabolites responsible for the differences in gender groups were citrate, creatinine, trimethylamine N-oxide, glycine, creatine and taurine, and for the differences in age groups they were citrate, creatinine, trimethylamine N-oxide and an unidentified metabolite (delta 3.78).

Applying genomics to organ transplantation medicine in both discovery and validation of biomarkers

The field of biomarker discovery made a significant leap over the past few decades. As we enter the Era of the Human Genome, thousands of biomarkers can be identified in a relatively high-throughput fashion. While such magnitude and diversity of biomarkers can be seen as a challenge by itself, the field is being moved forward by new advances in bioinformatics and Systems Biology. Because of the life and death nature of end stage organ failure that transplantation treats, the severe donor organ shortage, and the powerful and toxic drug therapies required for the lifetimes of transplant patients, we envision a future for biomarkers as tools to diagnose disease in its early stages, predict prognosis, suggest treatment options and then assist in the implementation of therapies. By harnessing the power of multiple technologies in parallel makes it possible to discover and then validate the next generation of biomarkers for transplantation. We see the road ahead diverge into two paths: one from biomarkers to diagnosis and therapy and the other to a new level of insight into the complex molecular networks that determine when a healthy state becomes diseased and dysfunctional.

Can personalized drug therapy be achieved? A closer look at pharmaco-metabonomics

Between 1930 and 1990, several dozen high-penetrance, predominantly monogenic disorders were identified and characterized, which led some investigators to speculate that individualized drug treatment was just around the corner. Informative DNA tests were sought to determine genetic predisposition to toxicity and cancer, thereby identifying individuals in which a drug was likely to be effective and those at increased risk of drug toxicity. These assays represent the leading edge of phenotype-genotype association studies, which are a major goal of clinical pharmacology and pharmacogenomics. Because of the complexity of the genome, however, the task is more challenging than anticipated originally. In the past decade we have come to appreciate how difficult it is to determine unequivocally either an exact phenotype or genotype. In the near future it seems unlikely that, by themselves, either transcriptomics or proteomics will be particularly helpful in achieving individualized drug therapy. However, recent advances in metabonomics are exciting and show promise. In the future, and perhaps in combination with proteomics, metabonomics might complement genomics in achieving personalized drug therapy.

Effect of acute dietary standardization on the urinary, plasma, and salivary metabolomic profiles of healthy humans

BACKGROUND

Metabolomics in human nutrition research is faced with the challenge that changes in metabolic profiles resulting from diet may be difficult to differentiate from normal physiologic variation.

OBJECTIVE

We assessed the extent of intra- and interindividual variation in normal human metabolic profiles and investigated the effect of standardizing diet on reducing variation.

DESIGN

Urine, plasma, and saliva were collected from 30 healthy volunteers (23 females, 7 males) on 4 separate mornings. For visits 1 and 2, free food choice was permitted on the day before biofluid collection. Food choice on the day before visit 3 was intended to mimic that for visit 2, and all foods were standardized on the day before visit 4. Samples were analyzed by using 1H nuclear magnetic resonance spectroscopy followed by multivariate data analysis.

RESULTS

Intra- and interindividual variations were considerable for each biofluid. Visual inspection of the principal components analysis scores plots indicated a reduction in interindividual variation in urine, but not in plasma or saliva, after the standard diet. Partial least-squares discriminant analysis indicated time-dependent changes in urinary and salivary samples, mainly resulting from creatinine in urine and acetate in saliva. The predictive power of each model to classify the samples as either night or morning was 85% for urine and 75% for saliva.

CONCLUSIONS

Urine represented a sensitive metabolic profile that reflected acute dietary intake, whereas plasma and saliva did not. Future metabolomics studies should consider recent dietary intake and time of sample collection as a means of reducing normal physiologic variation.

A bioinformatician's view of the metabolome

The study of a collection of metabolites as a whole (metabolome), as opposed to isolated small molecules, is a fast-growing field promising to take us one step further towards understanding cell biology, and relating the genetic capabilities of an organism to its observed phenotype. The new sciences of metabolomics and metabonomics can exploit a variety of existing experimental and computational methods, but they also require new technology that can deal with both the amount and the diversity of the data relating to the rich world of metabolites. More specifically, the collaboration between bioinformaticians and chemoinformaticians promises to advance our view of cognate molecules, by shedding light on their atomic structure and properties. Modelling of the interactions of metabolites with other entities in the cell, and eventually complete modelling of reaction pathways will be essential for analysis of the experimental data, and prediction of an organism's response to environmental challenges.

Lost in translation? Role of metabolomics in solving translational problems in drug discovery and development

Too few drug discovery projects generate a marketed drug product, often because preclinical studies fail to predict the clinical experience with a drug candidate. Improving the success of preclinical-to-clinical translation is of paramount importance in optimizing the pharmaceutical value chain. Here, we advance the case for a molecular systems approach to crossing the preclinical-to-clinical translational chasm and for metabolomic analysis of readily accessible bodyfluids as a key technology in translational activities.:

Melanoma Metastases in Regional Lymph Nodes Are Accurately Detected by Proton Magnetic Resonance Spectroscopy of Fine-Needle Aspirate Biopsy Samples

BACKGROUND

Nonsurgical assessment of sentinel nodes (SNs) would offer advantages over surgical SN excision by reducing morbidity and costs. Proton magnetic resonance spectroscopy (MRS) of fine-needle aspirate biopsy (FNAB) specimens identifies melanoma lymph node metastases. This study was undertaken to determine the accuracy of the MRS method and thereby establish a basis for the future development of a nonsurgical technique for assessing SNs.

METHODS

FNAB samples were obtained from 118 biopsy specimens from 77 patients during SN biopsy and regional lymphadenectomy. The specimens were histologically evaluated and correlated with MRS data. Histopathologic analysis established that 56 specimens contained metastatic melanoma and that 62 specimens were benign. A linear discriminant analysis-based classifier was developed for benign tissues and metastases.

RESULTS

The presence of metastatic melanoma in lymph nodes was predicted with a sensitivity of 92.9%, a specificity of 90.3%, and an accuracy of 91.5% in a primary data set. In a second data set that used FNAB samples separate from the original tissue samples, melanoma metastases were predicted with a sensitivity of 87.5%, a specificity of 90.3%, and an accuracy of 89.1%, thus supporting the reproducibility of the method.

CONCLUSIONS

Proton MRS of FNAB samples may provide a robust and accurate diagnosis of metastatic disease in the regional lymph nodes of melanoma patients. These data indicate the potential for SN staging of melanoma without surgical biopsy and histopathological evaluation.

Metabolomics in human nutrition: opportunities and challenges

Metabolomics has been widely adopted in pharmacology and toxicology but is relatively new in human nutrition. The ultimate goal, to understand the effects of exogenous compounds on human metabolic regulation, is similar in all 3 fields. However, the application of metabolomics to nutritional research will be met with unique challenges. Little is known of the extent to which changes in the nutrient content of the human diet elicit changes in metabolic profiles. Moreover, the metabolomic signal from nutrients absorbed from the diet must compete with the myriad of nonnutrient signals that are absorbed, metabolized, and secreted in both urine and saliva. The large-bowel microflora also produces significant metabolic signals that can contribute to and alter the metabolome of biofluids in human nutrition. Notwithstanding these possible confounding effects, every reason exists to be optimistic about the potential of metabolomics for the assessment of various biofluids in nutrition research. This potential lies both in metabolic profiling through the use of pattern-recognition statistics on assigned and unassigned metabolite signals and in the collection of comprehensive data sets of identified metabolites; both objectives have the potential to distinguish between different dietary treatments, which would not have been targeted with conventional techniques. The latter objective sets out a well-recognized challenge to modern biology: the development of libraries of small molecules to aid in metabolite identification. The purpose of the present review was to highlight some early challenges that need to be addressed if metabolomics is to realize its great potential in human nutrition.

Genomics and systems biology - how relevant are the developments to veterinary pharmacology, toxicology and therapeutics?

This review discusses some of the recent developments in genomics and its current and future relevance for veterinary pharmacology and toxicology. With the rapid progress made in this field several new approaches in pharmacological and toxicological research have developed and drug discovery and drug development strategies have changed dramatically. In this review, the term genomics is used to encompass the three sub-disciplines transcriptomics, proteomics and metabolomics (or metabonomics) to describe the formation and fate of mRNA, proteins and metabolites, respectively. The current status and methods of the technology and some applications are briefly described. Although the DNA sequencing programmes are receiving considerable attention, the real value of genomics for pharmacology and toxicology is brought by the parallel developments in bio-informatics, bio-statistics and the integration of biology with mathematics and information technology. The ultimate level of integration is now mostly called systems biology, where mRNA, proteins and metabolites are being analysed in parallel, using a complete arsenal of analytical techniques (DNA-array, LC-MS/MS, GC-MS/MS, NMR, etc.). The information thus collected is analysed, integrated, linked to database information and translated to pathways and systems. This approach offers an enormous potential to study disease mechanisms and find new drug targets. Thus far, genomics and systems biology have not been introduced significantly in typical veterinary pharmacological and toxicological research programmes. The high costs and complexity connected to these large projects often form major obstacles for research groups with limited budgets. In other veterinary areas and disciplines, including infectious diseases, animal production and food-safety more examples of application are available. Genomics and bio-informatics provide outstanding opportunities to study pharmacology and toxicology in a more holistic way, taking into account the complexity of biological systems and based on the basic principles of physiology and the concept of homeostasis. Knowledge of biology, in vivo and in vitro models, and comparative pharmacology/toxicology is essential here, creating excellent opportunities for the veterinary trained scientist.

Proton MR CSF analysis and a new software as predictors for the differentiation of meningitis in children

This article describes proton MR spectroscopic analysis of cerebrospinal fluid of 167 children suffering from meningitis and 24 control cases. Quantification of 12 well-separated and commonly observed cerebrospinal fluid metabolites viz., beta-hydroxybutyrate, lactate, alanine, acetate, acetone, acetoacetate, pyruvate, glutamine, citrate, creatine/creatinine, glucose (total) and urea was carried out using Bruker's NMRQUANT software with respect to a known concentration of sodium-3-(trimethylsilyl)-2,2,3,3-d4-propionate (TSP), serving as an external reference. The assignment of urea in CSF is reported for the first time by NMR. The presence of cyclopropane, observed for the first time in tuberculous meningitis overall in 85.1% of cases, acts as a finger-print marker for the differential diagnosis. Multivariate discriminant function analysis was carried out for the proton MR-detected metabolite information and the clinical symptoms data of the meningitis and control cases to find the important descriptors for classification, followed by a re-validation of the entire database. It was found that the control could be differentiated from the disease group with a success rate of 96.4%, followed by the differential diagnosis of tuberculous meningitis with a corresponding value of 77.2%. Excluding the presence of cyclopropane, bacterial meningitis could be classified 84.4% correct and viral meningitis with a rate of 83.3%. It is proposed that the NMR spectroscopic information, along with other routine clinical features, may serve as an additional diagnostic tool for the differential diagnosis of meningitis in children.

Gut microorganisms, mammalian metabolism and personalized health care

The mammalian gut microbiota interact extensively with the host through metabolic exchange and co-metabolism of substrates. Such metabolome-metabolome interactions are poorly understood, but might be implicated in the aetiology of many human diseases. In this paper, we assess the importance of the gut microbiota in influencing the disposition, fate and toxicity of drugs in the host, and conclude that appropriate consideration of individual human gut microbial activities will be a necessary part of future personalized health-care paradigms.

Metabolomics in the context of systems biology: bridging traditional Chinese medicine and molecular pharmacology

The introduction of the concept of systems biology, enabling the study of living systems from a holistic perspective based on the profiling of a multitude of biochemical components, opens up a unique and novel opportunity to reinvestigate natural products. In the study of their bioactivity, the necessary reductionistic approach on single active components has been successful in the discovery of new medicines, but at the same time the synergetic effects of components were lost. Systems biology, and especially metabolomics, is the ultimate phenotyping. It opens up the possibility of studying the effect of complex mixtures, such as those used in Traditional Chinese Medicine, in complex biological systems; abridging it with molecular pharmacology. This approach is considered to have the potential to revolutionize natural product research and to advance the development of scientific based herbal medicine.

Metabonomics, dietary influences and cultural differences: a 1H NMR-based study of urine samples obtained from healthy British and Swedish subjects

The aim of this study was to assess the feasibility and comparability of metabonomic data in clinical studies conducted in different countries without dietary restriction. A (1)H NMR-based metabonomic analysis was performed on urine samples obtained from two separate studies, both including male and female subjects. The first was on a group of healthy British subjects (n = 120), whilst the second was on healthy subjects from two European countries (Britain and Sweden, n = 30). The subjects were asked to provide single, early morning urine samples collected on a single occasion. The (1)H NMR spectra obtained for urine samples were visually inspected and analysed chemometrically using principal components analysis (PCA). These inspections highlighted outliers within the urine samples and displayed interesting differences, revealing characteristic dietary and cultural features between the subjects of both countries, such as high trimethylamine-N-oxide (TMAO)-excretion in the Swedish population and high taurine-excretion, due to the Atkins diet. This study suggests that the endogenous urinary profile is subject to distinct cultural and severe dietary influences and that great care needs to be taken in the interpretation of 'biomarkers of disease and response to drug therapy' for diagnostic purposes.

Modelling of multiple sclerosis: lessons learned in a non-human primate

The many, highly specific, biological therapies for immune-based diseases create a need for valid preclinical animal models. The wide immunological gap between human beings and laboratory mouse or rat models makes many disease models in these species invalid. In this review, we report a non-human-primate model of chronic multiple sclerosis (MS)-experimental autoimmune encephalitis (EAE) in the common marmoset (Callithrix jacchus)-that can help bridge this wide gap. The genetic and immunological similarity of marmosets and human beings and the clinical and neuropathological similarity of the EAE model to MS provide a unique experimental platform for research into basic immunopathogenetic mechanisms and for the development of more effective treatments for MS.

Study of cytokine induced neuropathology by high resolution proton NMR spectroscopy of rat urine

Multiple sclerosis is a major cause of non-traumatic neurological disability. The identification of markers that differentiate disease progression is critical to effective therapy. A combination of NMR spectroscopic metabolic profiling of urine and statistical pattern recognition was used to detect focal inflammatory central nervous system (CNS) lesions induced by microinjection of a replication-deficient recombinant adenovirus expressing TNF-alpha or IL1-beta cDNA into the brains of Wistar rats. These animals were compared with a group of naïve rats and a group of animals injected with an equivalent null adenovirus. Urine samples were collected 7 days after adenovirus injection, when the inflammatory lesion is maximally active. Principal components analysis and Partial Least Squares-Discriminate analysis of the urine (1)H NMR spectra revealed significant differences between each of the cytokine adenovirus groups and the control groups; for the TNF-alpha group the main differences lay in citrate and succinate, while for the IL-1beta group the predominant changes occurred in leucine, isoleucine, valine and myo-inositol. Thus, we can identify urinary metabolic vectors that not only separate rats with inflammatory lesions in the brain from control animals, but also distinguish between different types of CNS inflammatory lesions.

Non-invasive measurement of brain damage in a primate model of multiple sclerosis

Early recognition of whether a product has potential as a new therapy for treating multiple sclerosis (MS) relies upon the quality of the animal models used in the preclinical trials. The promising effects of new treatments in rodent models of experimental autoimmune encephalomyelitis (EAE) have rarely been reproduced in patients suffering from MS. EAE in outbred marmoset monkeys, Callithrix jacchus, is a valid new model, and might provide an experimental link between EAE in rodent models and human MS. Using magnetic resonance imaging techniques similar to those used in patients suffering from MS pathological abnormalities in the brain, white matter of the animal can be visualized and quantified. Moreover, NMR spectroscopy, in combination with pattern recognition, offers an advanced uroscopic technique for the identification of biomarkers of inflammatory demyelination.