Quantitative Lipoprotein Subclass and Low Molecular Weight Metabolite Analysis in Human Serum and Plasma by 1H NMR Spectroscopy in a Multilaboratory Trial.

We report an extensive 600 MHz NMR trial of quantitative lipoprotein and small-molecule measurements in human blood serum and plasma. Five centers with eleven 600 MHz NMR spectrometers were used to analyze 98 samples including 20 quality controls (QCs), 37 commercially sourced, paired serum and plasma samples, and two National Institute of Science and Technology (NIST) reference material 1951c replicates. Samples were analyzed using rigorous protocols for sample preparation and experimental acquisition. A commercial lipoprotein subclass analysis was used to quantify 105 lipoprotein subclasses and 24 low molecular weight metabolites from the NMR spectra. For all spectrometers, the instrument specific variance in measuring internal QCs was lower than the percentage described by the National Cholesterol Education Program (NCEP) criteria for lipid testing [triglycerides <2.7%; cholesterol <2.8%; low-density lipoprotein (LDL) cholesterol <2.8%; high-density lipoprotein (HDL) cholesterol <2.3%], showing exceptional reproducibility for direct quantitation of lipoproteins in both matrixes. The average relative standard deviations (RSDs) for the 105 lipoprotein parameters in the 11 instruments were 4.6% and 3.9% for the two NIST samples, whereas they were 38% and 40% for the 37 commercially sourced plasmas and sera, respectively, showing negligible analytical compared to biological variation. The coefficient of variance (CV) obtained for the quantification of the small molecules across the 11 spectrometers was below 15% for 20 out of the 24 metabolites analyzed. This study provides further evidence of the suitability of NMR for high-throughput lipoprotein subcomponent analysis and small-molecule quantitation with the exceptional required reproducibility for clinical and other regulatory settings.

A combination of NMR and liquid chromatography to characterize the protective effects of Rhus tripartita extracts on ethanol-induced toxicity and inflammation on intestinal cells.

Consumption of ethanol may have severe effects on human organs and tissues and lead to acute and chronic inflammation of internal organs. The present study aims at investigating the potential protective effects of three different extracts prepared from the leaves, root, and stem of the sumac, Rhus tripartita, against ethanol-induced toxicity and inflammation using intestinal cells as a cell culture system, in vitro model of the intestinal mucosa. The results showed an induction of cytotoxicity by ethanol, which was partially reversed by co-administration of the plant extracts. As part of investigating the cellular response and the mechanism of toxicity, the role of reduced thiols and glutathione-S-transferases were assessed. In addition, intestinal cells were artificially imposed to an inflammation state and the anti-inflammatory effect of the extracts was estimated by determination of interleukin-8. Finally, a detailed characterization of the contents of the three plant extracts by high resolution Nuclear Magnetic Resonance (NMR) spectroscopy and mass spectrometry revealed significant differences in their chemical compositions.

Nuclear Magnetic Resonance Strategies for Metabolic Analysis.

NMR spectroscopy is a powerful tool for metabolomic studies, offering highly reproducible and quantitative analyses. This burgeoning field of NMR metabolomics has been greatly aided by the development of modern spectrometers and software, allowing high-throughput analysis with near real-time feedback. Whilst one-dimensional proton (1D-1H) NMR analysis is best described and remains most widely used, a plethora of alternative NMR techniques are now available that offer additional chemical and structural information and resolve many of the limitations of conventional 1D-1H NMR such as spectral overlay. In this book chapter, we review the principal concepts of practical NMR spectroscopy, from common sample preparation protocols to the benefits and theoretical concepts underpinning the commonly used pulse sequences. Finally, as a case study to highlight the utility of NMR as a method for metabolomic investigation, we have detailed how NMR has been used to gain valuable insight into the metabolism occurring in kidneys prior to transplantation and the potential implications of this.