Experimental encephalomyelitis modulates inositol and taurine in the spinal cord of Biozzi mice

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.

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.

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.

Magnetic resonance imaging for detection and analysis of mouse phenotypes

With the enormous and growing number of experimental and genetic mouse models of human disease, there is a need for efficient means of characterizing abnormalities in mouse anatomy and physiology. Adaptation of magnetic resonance imaging (MRI) to the scale of the mouse promises to address this challenge and make major contributions to biomedical research by non-invasive assessment in the mouse. MRI is already emerging as an enabling technology providing informative and meaningful measures in a range of mouse models. In this review, recent progress in both in vivo and post mortem imaging is reported. Challenges unique to mouse MRI are also identified. In particular, the needs for high-throughput imaging and comparative anatomical analyses in large biological studies are described and current efforts at handling these issues are presented.

Cannabinoids inhibit neurodegeneration in models of multiple sclerosis

Multiple sclerosis is increasingly being recognized as a neurodegenerative disease that is triggered by inflammatory attack of the CNS. As yet there is no satisfactory treatment. Using experimental allergic encephalo myelitis (EAE), an animal model of multiple sclerosis, we demonstrate that the cannabinoid system is neuroprotective during EAE. Mice deficient in the cannabinoid receptor CB1 tolerate inflammatory and excitotoxic insults poorly and develop substantial neurodegeneration following immune attack in EAE. In addition, exogenous CB1 agonists can provide significant neuroprotection from the consequences of inflammatory CNS disease in an experimental allergic uveitis model. Therefore, in addition to symptom management, cannabis may also slow the neurodegenerative processes that ultimately lead to chronic disability in multiple sclerosis and probably other diseases.

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

Proton nuclear magnetic resonance (1H-NMR) spectroscopy in combination with pattern recognition techniques were used to investigate the composition of organic compounds in urines from patients with multiple sclerosis (MS), patients with other neurological diseases (OND) and healthy controls (H). Using a valid animal model of MS, namely the common marmoset (Callithrix jacchus) model of experimental autoimmune encephalomyelitis (EAE), the relation of disease progression and alteration of the urine composition was investigated. Urine samples were collected during different stages of EAE, either induced with whole human myelin or with the myelin protein MOG in complete adjuvant. The urine samples were analysed with 1H-NMR spectroscopy allowing simultaneous detection of an array of compounds. Spectral differences between urines from EAE-affected and healthy monkeys were assessed with multivariate analysis. Evidence is provided that development of EAE is associated with changes in the chemical composition of the urine, in particular of compounds with NMR peaks in the region of the spectrum between 0.5 and 3.50 ppm. In addition, we found preliminary evidence for differences between urines from MS, OND and H groups.

Endocannabinoids control spasticity in a multiple sclerosis model

Spasticity is a complicating sign in multiple sclerosis that also develops in a model of chronic relapsing experimental autoimmune encephalomyelitis (CREAE) in mice. In areas associated with nerve damage, increased levels of the endocannabinoids, anandamide (arachidonoylethanolamide, AEA) and 2-arachidonoyl glycerol (2-AG), and of the AEA congener, palmitoylethanolamide (PEA), were detected here, whereas comparable levels of these compounds were found in normal and non-spastic CREAE mice. While exogenously administered endocannabinoids and PEA ameliorate spasticity, selective inhibitors of endocannabinoid re-uptake and hydrolysis-probably through the enhancement of endogenous levels of AEA, and, possibly, 2-arachidonoyl glycerol-significantly ameliorated spasticity to an extent comparable with that observed previously with potent cannabinoid receptor agonists. These studies provide definitive evidence for the tonic control of spasticity by the endocannabinoid system and open new horizons to therapy of multiple sclerosis, and other neuromuscular diseases, based on agents modulating endocannabinoid levels and action, which exhibit little psychotropic activity.

Identification of a high concentration of scyllo-inositol in the brain of a healthy human subject using 1H- and 13C-NMR

The peak at 3.35 ppm in the 1H-NMR spectrum characteristic for scyllo-inositol may be a marker for cerebral pathology, although it has a well-known constant concentration relative to myo-inositol. Such a peak was observed with an intensity at least 300% above normal in the brain of a healthy volunteer. The scyllo-inositol signal was assigned based on the detection of a corresponding peak at 74.5 ppm in the 13C-NMR spectrum and on the demonstration of singlet characteristics of the proton signal. The presence of substantial brain concentrations of scyllo-inositol suggests that scyllo-inositol metabolism may be regulated independently from myo-inositol and that such concentrations are compatible with normal health.

Quantitative and qualitative characterization of 1H NMR spectra of colon tumors, normal mucosa and their perchloric acid extracts: decreased levels of myo-inositol in tumours can be detected in intact biopsies

Sixteen colonic tumours and 10 normal mucosa biopsies have been examined by 1H NMR spectroscopy at 9.4 T. A complete characterization and quantification of the aliphatic region of PCA extract spectra and the analysis of the two-dimensional COSY spectra of five pairs of intact biopsies (tumor and control mucosa) has been carried out. The analysis of the PCA extracts demonstrated a significant increase in the concentration of the endogenous compounds: lactate, glutamate, aspartate, taurine, spermine, glutathione and glycerophosphoethanolamine, and a significant decrease of myo- and scyllo-inositol, in tumours with respect to mucosae. Among these metabolites, the high myo-inositol and taurine levels and the reciprocal changes found between them in tumours and mucosae make their resonances interesting as possible malignancy markers if they are detectable in vivo. In contrast to the easy observation of taurine in one-dimensional spectra of intact biopsies, the difficulty of observing myo-inositol prompted us to use two-dimensional COSY spectra for the detection and quantification of both these metabolites. In the two-dimensional spectra, the use of a ratio between the cross-peak volumes of both metabolites permits an excellent differentiation between tumours and normal mucosa and suggests its potential to detect malignant changes in the healthy tissue, provided a two-dimensional approach is used.