1H-NMR-Based Metabolomic Profiling of CSF in Early Amyotrophic Lateral Sclerosis

Hélène Blasco,Julien Praline,Philippe Corcia,Pierre-François Pradat,Caroline Moreau,Patrick Vourc'H,Ségolène Veau,Christian R Andres,Lydie Nadal-Desbarats,Clémentine Fournier,Paul Gordon,David Devos,Patrick Emond,Vladimir N Uversky

doi:10.1371/journal.pone.0013223

Abstract

BackgroundPathophysiological mechanisms involved in amyotrophic lateral sclerosis (ALS) are complex and none has identified reliable markers useful in routine patient evaluation. The aim of this study was to analyze the CSF of patients with ALS by 1H NMR (Nuclear Magnetic Resonance) spectroscopy in order to identify biomarkers in the early stages of the disease, and to evaluate the biochemical factors involved in ALS.MethodologyCSF samples were collected from patients with ALS at the time of diagnosis and from patients without neurodegenerative diseases. One and two-dimensional 1H NMR analyses were performed and metabolites were quantified by the ERETIC method. We compared the concentrations of CSF metabolites between both groups. Finally, we performed principal component (PCA) and discriminant analyses.Principal FindingsFifty CSF samples from ALS patients and 44 from controls were analyzed. We quantified 17 metabolites including amino-acids, organic acids, and ketone bodies. Quantitative analysis revealed significantly lower acetate concentrations (p = 0.0002) in ALS patients compared to controls. Concentration of acetone trended higher (p = 0.015), and those of pyruvate (p = 0.002) and ascorbate (p = 0.003) were higher in the ALS group. PCA demonstrated that the pattern of analyzed metabolites discriminated between groups. Discriminant analysis using an algorithm of 17 metabolites revealed that patients were accurately classified 81.6% of the time.Conclusion/SignificanceCSF screening by NMR spectroscopy could be a useful, simple and low cost tool to improve the early diagnosis of ALS. The results indicate a perturbation of glucose metabolism, and the need to further explore cerebral energetic metabolism.

Highlights

Amyotrophic lateral sclerosis (ALS), the most common adultonset motor neuron disease, is characterized by degeneration of both lower and upper motor neurons leading to death within 2–5 years of onset [1]
Metabolomic studies have been performed via different analytical methods such as high performance liquid chromatography followed by electrochemical detection [8] or high resolution 1H NMR (Nuclear Magnetic Resonance) spectroscopy [9]
Qualitative analysis of cerebrospinal fluid (CSF) by superimposition of spectra from amyotrophic lateral sclerosis (ALS) patients and controls did not reveal any differences in metabolite composition.We found no trace of BMAA in the CSF of our ALS patients

Summary

Introduction

Amyotrophic lateral sclerosis (ALS), the most common adultonset motor neuron disease, is characterized by degeneration of both lower and upper motor neurons leading to death within 2–5 years of onset [1]. While many in vivo studies have provided clues to pathogenesis mechanisms, none has identified reliable markers useful in routine patient evaluation. NMR spectroscopy appears to be cost-effective, useful in routine care, and screening [10]. Different kinds of biological fluids have been screened [11], but CSF may have the highest yield of biomarkers in ALS because of its direct contact with the brain, its accessibility, and its dynamic changes with the cerebral environment. Pathophysiological mechanisms involved in amyotrophic lateral sclerosis (ALS) are complex and none has identified reliable markers useful in routine patient evaluation. The aim of this study was to analyze the CSF of patients with ALS by 1H NMR (Nuclear Magnetic Resonance) spectroscopy in order to identify biomarkers in the early stages of the disease, and to evaluate the biochemical factors involved in ALS

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Conclusion