Metabolomic profiling of CSF in multiple sclerosis and neuromyelitis optica spectrum disorder by nuclear magnetic resonance.

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) are inflammatory diseases of the central nervous system. Although several studies have characterized the metabolome in the cerebrospinal fluid (CSF) from MS and NMOSD patients, comparative analyses between them and between the relapse and the remission of each disease have not been performed. Both univariate and multivariate analyses were used to compare 1H-NMR spectra of CSF from MS, NMOSD, and healthy controls (HCs). The statistical analysis showed alterations of eight metabolites that were dependent on the disease. Levels of 2-hydroxybutyrate, acetone, formate, and pyroglutamate were higher and levels of acetate and glucose were lower in both MS and NMOSD. Citrate was lower in MS patients, whereas lactate was higher in only NMOSD specifically. The shared feature of metabolic changes between MS and NMOSD may be related to altered energy metabolism and fatty acid biosynthesis in the brain. Another analysis to characterize relapse and remission status showed that isoleucine and valine were down-regulated in MS relapse compared to MS remission. The other metabolites identified in the disease comparison showed the same alterations regardless of disease activity. These findings would be helpful in understanding the biological background of these diseases, and distinguishing between MS and NMOSD, as well as determining the disease activity.

Analysis of glutamine, glutamate, pyroglutamate, and GABA in cerebrospinal fluid using ion pairing HPLC with positive electrospray LC/MS/MS.

A simple and sensitive method for the separation and quantitation of glutamine, glutamate, pyroglutamate, and gamma-aminobutyric acid (GABA) in cerebrospinal fluid (CSF) is presented. The method utilizes ion pairing with heptafluorobutyric acid (HFBA) to achieve HPLC separation with detection by positive ESI LC/MS/MS. The method does not require extraction or derivatization, utilizes a heavy labeled internal standard for each analyte, and allows for rapid throughput with a 5 min run time. The method was developed with particular attention taken to prevent conversion between analytes known to occur under certain conditions. The lower limit of quantitation is 7.8 ng/ml for all analytes, and the intra-day and inter-day accuracy (%RE) and precision (%R.S.D.) are defined for all analytes. The method was developed as a sensitive, selective, and robust method to investigate the excitatory and inhibitory neurotransmitters (glutamate and GABA) as biomarkers in drug development.

Striatal deficiency of L-pyroglutamic acid in Huntington's disease is accompanied by increased plasma levels.

L-Pyroglutamic acid (L-PGA), a cyclized glutamate analogue, was measured in plasma, cerebrospinal fluid and brain tissue of patients with Huntington's disease (HD) and controls. In HD, plasma L-PGA was elevated and possibly reflects an increased requirement of cell membranes to be protected against peroxidative damage. L-PGA was decreased in caudate and putamen of HD patients. We suggest that striatal deficiency of L-PGA in HD is a consequence of neuronal loss which characteristically occurs in HD striatum.

Hyperglycinemia and propionyl coA carboxylase deficiency and episodic severe illness without consistent ketosis.

Propionyl CoA carboxylase deficiency was found in a 7-month-old boy who presented with attacks of vomiting, anorexia, weight loss, weakness, and hypotonia. He failed to thrive and had generalized seizures. He had propionic acidemia and hyperglycinemia; these are the manifestations of the ketotic hyperglycinemia syndrome. However, ketonuria was not a consistent part of his clinical picture, and he had at least two episodes of acute overwhelming illness, the latter one fatal, in which ketones were never found in the urine. Large amounts of pyrrolidone carboxylic acid were found in body fluids.