Comment

Metabolic phenotyping for monitoring surgical patients

Baicalein (5,6,7-trihydroxyflavone), isolated from the root of traditional Chinese herb Scutellaria baicalensis Georgi, has anti-inflammatory and anti-oxidative activities. This study explored the protective and modulatory mechanisms of baicalein on neuroinflammation, oxidative stress and metabolic abnormality in lipopolysaccharide (LPS)-activated BV-2 cells. Our results demonstrated that treatment with baicalein remarkably restrained the production of pro-inflammatory factors including nitric oxide (NO), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in LPS-activated BV-2 cells. Moreover, baicalein significantly inhibited reactive oxygen species (ROS) production, decreased cyclooxygenase-2 (COX-2) and nuclear factor-b (NF-κB)/p65 expression. ¹H NMR metabolomics analysis revealed that 12 differential metabolites were regulated by baicalein, implicated in alanine, aspartate and glutamate metabolism, glutathione metabolism, arginine and proline metabolism, D-glutamine and D-glutamate metabolism. In conclusion, these results indicated that baicalein has protective and modulatory effects on neuroinflammation and oxidative stress in LPS-activated BV-2 cells.

Understanding metabotype (multicomponent metabolic characteristics) variation can help to generate new diagnostic and prognostic biomarkers, as well as models, with potential to impact on patient management. We present a suite of conceptual approaches for the generation, analysis, and understanding of metabotypes from body fluids and tissues. We describe and exemplify four fundamental approaches to the generation and utilization of metabotype data via multiparametric measurement of (i) metabolite levels, (ii) metabolic trajectories, (iii) metabolic entropies, and (iv) metabolic networks and correlations in space and time. This conceptual framework can underpin metabotyping in the scenario of personalized medicine, with the aim of improving clinical outcomes for patients, but the framework will have value and utility in areas of metabolic profiling well beyond this exemplar.

Preliminary candidate gene and genome-wide association studies (GWAS) suggest that susceptibility to adverse perioperative events, including cardiac (myocardial infarction, ventricular dysfunction, atrial fibrillation), neurologic, and renal (among others) is genetically determined. Potential applications of biomarkers in perioperative medicine and critical care include prognosis, diagnosis, and monitoring of adverse outcomes, as well as informing and refining therapeutic decisions. So far, very few have been rigorously evaluated to demonstrate additive performance to existing risk stratification models (clinical validity) or change therapy (clinical utility). Most promising among those are natriuretic peptides and C-reactive protein for predicting risk of major adverse cardiovascular events, and procalcitonin to assess infection in the critically ill.

Metabolomics is the comprehensive assessment of endogenous metabolites of a biological system in a holistic context, and its property consists with the global view of Traditional Chinese Medicine (TCM). Shuihonghuazi Formula (SHHZF) has been used for liver cancer early treatment in clinical for more than thirty years, but its mechanism remains unclear completely. This paper was designed to explore the therapeutic effects of SHHZF on liver cancer and its metabolomic characters.

All the rats were given diethylnitrosamine (DEN) at the dosage of 70 mg/kg for 14 weeks. From the 7th weeks, SHHZF was given to the rats which lasted for 10 weeks. Therapeutic effects of SHHZF was compared with that of cyclophosphamide (CTX). High performance liquid-chromatography/electrospray-ionization time of flight mass spectrometer (HPLC/ESI-TOF-MS) combined with pattern recognition approaches including principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA), was integrated to approximate the comprehensive metabolic signature and discover differentiating metabolites by Agilent MPP 12.1. The changes in metabolic profiling in plasma were restored to their baseline values after SHHZF treatment according to the PLS-DA score plots.

The results indicated that 23 ions as “differentiating metabolites”. The alterations in those metabolites were associated with perturbations in fatty acid and bile acid metabolism, in response to liver cancer through immune and nervous system. And SHHZF could increase the uptake and utilization of linoleic acid and oleic acid, increase arachidonic acid-like substance content and enhance organism immunity of liver cancer rats. And it also could increase the translation from phosphatidylethanolamine (PE) to phosphatidylcholine (PC), linoleic acid metabolism and inhibits abnormal metabolism of bile acid.

The mechanism of therapeutic effects of SHHZF on liver cancer by adjusting the activities of PE N-methyl transferase (PEMT), Lysophospholipase D, methylenetetrahydrofolate reductase (MTHFR) and lysophospholipase was elucidated by the method of metabonomics for the first time.

Non-destructive proton nuclear magnetic resonance (¹H NMR) spectroscopy and highly sensitive ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (U-HPLC/Q-TOF-MS) coupled to data processing methods were applied to analyze the metabolic profiling changes of glycerophospholipids (GPLs) in RAW264.7 cells from inflammation to prognosis. Analysis of ¹H NMR was shown that the models were grouped successfully, illustrating that all of them had significant differences. Based on the highly simple, accurate, non-targeted and non-destructively advantages of ¹H NMR, it could be used as a new screening tool of anti-inflammatory drugs in the metabolic profiling of GPLs. 58 GPLs were identified by U-HPLC/Q-TOF-MS, and 19 components were firstly identified in this study compared with our previous results. In addition, ten potential biomarkers were proved, of which phosphatidylcholine (PC) (16:0/18:1) and (18:0/18:1) changed consistently in three drug-induced groups and might be the important biomarkers. Compared with ¹H NMR, U-HPLC/Q-TOF-MS showed higher sensitivity and specificity and was more suitable for the determination of biomarkers apart from the deficiency of time-consuming sample preparation steps and unambiguous metabolite identification. Therefore, it is feasible to analyze the changes of GPLs during inflammation by combining ¹H NMR spectroscopy with U-HPLC/Q-TOF-MS. The metabolic profiling of GPLs provides valuable evidence for inflammation diagnosis and prognosis, and might unravel the mechanisms involved in inflammation progression.

Methylamines are biologically-active metabolites present in serum and urine samples, which play complex roles in metabolic diseases. Methylamines can be detected by proton nuclear magnetic resonance (NMR), but specific methods remain to be developed for their routine assay in human serum in clinical settings. Here we developed and validated a novel reliable “methylamine panel” method for simultaneous quantitative analysis of trimethylamine (TMA), its major detoxification metabolite trimethylamine-N-oxide (TMAO), and precursors choline, betaine and l-carnitine in human serum using Ultra Performance Liquid Chromatography (UPLC) coupled to High Resolution Mass Spectrometry (HRMS). Metabolite separation was carried out on a HILIC stationary phase. For all metabolites, the assay was linear in the range of 0.25–12.5 μmol/L and enabled to reach limit of detection of about 0.10 μmol/L. Relative standard deviations were below 16% for the three levels of concentrations. We demonstrated the strong reliability and robustness of the method, which was applied to serum samples from healthy individuals to establish the range of concentrations of the metabolites and their correlation relationships and detect gender differences. Our data provide original information for implementing in a clinical environment a MS-based diagnostic method with potential for targeted metabolic screening of patients at risk of cardiometabolic diseases.