Quantification of 1H NMR spectra of human cerebrospinal fluid: a protocol based on constrained total-line-shape analysis

A protocol for quantitative ¹H NMR analysis of human cerebrospinal fluid (hCSF) was built up and assessed as based on Constrained Total-Line-Shape (CTLS) fitting. In this method, linear constraints were applied to spectral structures. The ¹H NMR spectra of 45 human CSF samples were measured and quantified using the CTLS method. The quantification strategies based on total-line-shape fitting are discussed. The metabolic model for CTLS includes 31 metabolites covering 85% of the total spectral intensity, excluding the protein contribution. Prior to data analysis, the data was divided into patients with no Alzheimer’s disease (AD), but with a normal AD marker profile (the peptide β-amyloid₄₂ and tau protein) present in CSF, and into controls that do not have an AD marker profile in CSF. Unexpectedly large variations in metabolite concentrations within the two patient groups were detected, but an analysis of variance revealed a significant (P = 0.027) difference only in the concentration of creatinine which was higher in patients that had a normal AD marker profile. Multivariate classification tools such as self-organizing maps (SOM) failed in separation of the two classes.     

Mitochondrial 2,4-dienoyl-CoA Reductase Deficiency in Mice Results in Severe Hypoglycemia with Stress Intolerance and Unimpaired Ketogenesis

The mitochondrial β-oxidation system is one of the central metabolic pathways of energy metabolism in mammals. Enzyme defects in this pathway cause fatty acid oxidation disorders. To elucidate the role of 2,4-dienoyl-CoA reductase (DECR) as an auxiliary enzyme in the mitochondrial β-oxidation of unsaturated fatty acids, we created a DECR–deficient mouse line. In Decr^−/− mice, the mitochondrial β-oxidation of unsaturated fatty acids with double bonds is expected to halt at the level of trans-2, cis/trans-4-dienoyl-CoA intermediates. In line with this expectation, fasted Decr^−/− mice displayed increased serum acylcarnitines, especially decadienoylcarnitine, a product of the incomplete oxidation of linoleic acid (C_18:2), urinary excretion of unsaturated dicarboxylic acids, and hepatic steatosis, wherein unsaturated fatty acids accumulate in liver triacylglycerols. Metabolically challenged Decr^−/− mice turned on ketogenesis, but unexpectedly developed hypoglycemia. Induced expression of peroxisomal β-oxidation and microsomal ω-oxidation enzymes reflect the increased lipid load, whereas reduced mRNA levels of PGC-1α and CREB, as well as enzymes in the gluconeogenetic pathway, can contribute to stress-induced hypoglycemia. Furthermore, the thermogenic response was perturbed, as demonstrated by intolerance to acute cold exposure. This study highlights the necessity of DECR and the breakdown of unsaturated fatty acids in the transition of intermediary metabolism from the fed to the fasted state.     

Beta diversity of stream diatoms at two hierarchical spatial scales: implications for biomonitoring

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