Characterization and Detection of Erythropoietin Fc Fusion Proteins Using Liquid Chromatography–Mass Spectrometry

Erythropoietin Fc (EPO-Fc) fusion proteins are potential drug candidates that have been designed for the treatment of anemia in humans by stimulating erythrocyte production. Such compounds can be considered performance-enhancing agents that may be used by athletes in endurance sports. This study describes the primary structure of commercially available EPO-Fc based on comprehensive liquid chromatography coupled with mass spectrometry (LC–MS) analysis. A bottom-up approach and the intact molecular weight (MW) measurement of deglycosylated protein and its IdeS proteolytic fractions was used to determine the amino acid sequence of EPO-Fc. Using multiple proteases, peptides covering unknown fusion breakpoints (spacer peptides) were identified. We demonstrated that “spacer peptides” can be used in the determination of EPO-Fc fusion proteins in biological samples using common LC–tandem MS methods

Target Metabolome Profiling-Based Machine Learning as a Diagnostic Approach for Cardiovascular Diseases in Adults

Metabolomics is a promising technology for the application of translational medicine to cardiovascular risk. Here, we applied a liquid chromatography/tandem mass spectrometry approach to explore the associations between plasma concentrations of amino acids, methylarginines, acylcarnitines, and tryptophan catabolism metabolites and cardiometabolic risk factors in patients diagnosed with arterial hypertension (HTA) (n = 61), coronary artery disease (CAD) (n = 48), and non-cardiovascular disease (CVD) individuals (n = 27). In total, almost all significantly different acylcarnitines, amino acids, methylarginines, and intermediates of the kynurenic and indolic tryptophan conversion pathways presented increased (p< 0.05) in concentration levels during the progression of CVD, indicating an association of inflammation, mitochondrial imbalance, and oxidative stress with early stages of CVD. Additionally, the random forest algorithm was found to have the highest prediction power in multiclass and binary classification patients with CAD, HTA, and non-CVD individuals and globally between CVD and non-CVD individuals (accuracy equal to 0.80 and 0.91, respectively). Thus, the present study provided a complex approach for the risk stratification of patients with CAD, patients with HTA, and non-CVD individuals using targeted metabolomics profiling

Pharmacokinetic Properties of the Novel Synthetic Cannabinoid 5F-APINAC and Its Influence on Metabolites Associated with Neurotransmission in Rabbit Plasma

The strong psychoactive effects of synthetic cannabinoids raise the need for the deeper studying of their neurometabolic effects. The pharmacokinetic properties of 5F-APINAC and its influence on metabolomics profiles associated with neurotransmission were investigated in rabbit plasma. Twelve rabbits divided into three groups received 1-mL 5F-APINAC at 0.1, 1 and 2 mg/kg. The intervention groups were compared with the controls. Sampling was performed at nine time points (0–24 h). Ultra-high-performance liquid chromatography–tandem mass spectrometry was used. The pharmacokinetics were dose-dependent (higher curve at a higher dose) with a rapid biotransformation, followed by gradual elimination within 24 h. The tryptophan concentrations abruptly decreased (p < 0.05) in all tested groups, returning to the basal levels after 6 h. 5-hydroxylindole acetic acid increased (p < 0.05) in the controls, but this trend was absent in the treated groups. The aspartic acid concentrations were elevated (p < 0.001) in the treated groups. L-kynurenine was elevated (p < 0.01) in the intervention groups receiving 1 mg/kg to 2 mg/kg. Dose-dependent elevations (p < 0.01) were found for kynurenic acid, xanthurenic acid and quinolinic acid (p < 0.01), whereas the anthranilic acid trends were decreased (p < 0.01). The indole-3-propionic acid and indole-3-carboxaldehyde trends were elevated (p < 0.05), whereas the indole-3-lactic acid trajectories were decreased (p < 0.01) in the intervention groups. 5F-APINAC administration had a rapid biotransformation and gradual elimination. The metabolites related to the kynurenine and serotonergic system/serotonin pathways, aspartic acid innervation system and microbial tryptophan catabolism were altered