Enantioselectivity Effects in Clinical Metabolomics and Lipidomics.

Metabolomics and lipidomics have demonstrated increasing importance in underlying biochemical mechanisms involved in the pathogenesis of diseases to identify novel drug targets and/or biomarkers for establishing therapeutic approaches for human health. Particularly, bioactive metabolites and lipids have biological activity and have been implicated in various biological processes in physiological conditions. Thus, comprehensive metabolites, and lipids profiling are required to obtain further advances in understanding pathophysiological changes that occur in cells and tissues. Chirality is one of the most important phenomena in living organisms and has attracted long-term interest in medical and natural science. Enantioselective separation plays a pivotal role in understanding the distribution and physiological function of a diversity of chiral bioactive molecules. In this context, it has been the goal of method development for targeted and untargeted metabolomics and lipidomic assays. Herein we will highlight the benefits and challenges involved in these stereoselective analyses for clinical samples.

Plasma Lipid Profile Reveals Plasmalogens as Potential Biomarkers for Colon Cancer Screening.

In this era of precision medicine, there is an increasingly urgent need for highly sensitive tests for detecting tumors such as colon cancer (CC), a silent disease where the first symptoms may take 10-15 years to appear. Mass spectrometry-based lipidomics is an emerging tool for such clinical diagnosis. We used ultra-performance liquid chromatography coupled to electrospray ionization quadrupole time-of-flight mass spectrometry operating in high energy collision spectral acquisition mode (MSE) mode (UPLC-QTOF-MSE) and gas chromatography (GC) to investigate differences between the plasmatic lipidic composition of CC patients and control (CTR) subjects. Key enzymes in lipidic metabolism were investigated using immuno-based detection assays. Our partial least squares discriminant analysis (PLS-DA) resulted in a suitable discrimination between CTR and CC plasma samples. Forty-two statistically significant discriminating lipids were putatively identified. Ether lipids showed a prominent presence and accordingly, a decrease in glyceronephosphate O-acyltransferase (GNPAT) enzyme activity was found. A receiver operating characteristic (ROC) curve built for three plasmalogens of phosphatidylserine (PS), named PS(P-36:1), PS(P-38:3) and PS(P-40:5), presented an area under the curve (AUC) of 0.998, and sensitivity and specificity of 100 and 85.7% respectively. These results show significant differences in CC patients' plasma lipid composition that may be useful in discriminating them from CTR individuals with a special role for plasmalogens.

Metabolomic investigation of human diseases biomarkers by CE and LC coupled to MS.

Metabolomics is one of the most recent trends in the "omics" era that investigates the end products of an organism activity, that is, all metabolites in a biological system, which are small molecules (less than 1000 Da) from different chemical classes. Metabolomics represents a tool to assess the biochemical activity of a living system through the analysis of substrates and products processed during the metabolism. The analysis of the metabolic profile (nontargeted analysis, i.e. a comparison between samples profiles of individuals) and of specific metabolites (targeted analysis, which quantifies a selected group of metabolites) in biological samples provides an insight into the metabolic state and the biochemical processes of the organism and, therefore, may indicate the onset and the stage of different diseases. An early and accurate diagnosis is essential for successful treatment and probable cure of most illnesses; hence, the investigation of metabolites as disease biomarkers has increased considerably in recent years. This review aims to present the most relevant works that address the nontargeted and targeted analysis of metabolites in different diseases for the past 10 years, including kidney and neurological disorders, cardiovascular diseases, diabetes, and cancer, using CE and LC coupled with the accurate detection of mass spectroscopy.

Extraction of tetracyclinic antibiotic residues from fish filet: comparison and optimization of different procedures using liquid chromatography with fluorescence detection.

Anti-microbials have been used to control the quality of the aquatic environment for both prophylactic and therapeutic purposes. Tetracyclines are among the main antimicrobials used in aquaculture, and present a particular difficulty for extraction, due to a complex structure and high interaction with components of the biological matrix. In this study, different techniques of extraction and clean-up of antimicrobials of the tetracycline class in tilapia filets have been optimized and compared, followed by validation of the methodology using the best procedure. Oxytetracycline, doxycycline, tetracycline and chlortetracycline were analyzed by HPLC-fluorescence under the following conditions: organic mobile phase composed of methanol:acetonitrile (1:1, v/v) and aqueous mobile phase containing sodium acetate (0.0375molL(-1)), calcium chloride (0.0175molL(-1)) and EDTA (0.0125molL(-1)) at pH 7.00. The chromatographic analysis was performed using a mobile phase gradient with a flow rate of 1mLmin(-1) and detection wavelength of 385/528nm (λexc/λem). Four extraction methods have been evaluated, namely: liquid-liquid partition; solid phase extraction (SPE) using phenyl, C18 and polymeric Oasis-HLB stationary phases; dispersive SPE (dSPE) using polymeric adsorbent XAD 16 resin; and QuEChERS. The methods have been optimized with fractional factorial experimental design and compared by the extraction efficiency. The liquid-liquid extraction and the QuEChERS methods showed low extraction efficiencies (14-30%) for the analytes. The use of dSPE showed good efficiency (40-60%), but with low precision and high consumption of time. Among the evaluated extraction techniques the use of SPE showed the best results, with emphasis on the phenyl phase (58-76%), and has been validated for analysis of residues of tetracyclines in tilapia muscle regarding selectivity, linearity, precision and limits of detection and quantification. The validated method was adequate for the investigation of the analytes at residue levels.