1,721,065 research outputs found
Quantification of trimethylamine-N-oxide (TMAO) and its main related trimethylammonium-containing compounds in human plasma by LC-MS/MS
No full textBackground: Trimethylammonium-containing compounds, including choline (CHOL), carnitine (CAR), trimethylglycine (TMG), ergothioneine (ERT), Nε,Nε,Nε-trimethyllysine (TML), γ-butyrobetaine (gBB), and dimethylglycine (DMG) contribute to trimethylamine N-oxide (TMAO) production, a metabolite linked to cardiovascular, renal, and metabolic diseases. An LC-MS/MS method has been established for their simultaneous measurement in human plasma, as an accurate quantification of TMAO and its precursors is crucial for understanding its clinical relevance. Methods: Blood samples from ten healthy male volunteers were processed using acetonitrile protein precipitation. Analysis was performed using a HILIC column and an isocratic methanol-formic acid mobile phase, achieving a total run time of less than 6 min. Linearity was adequate for all analytes (R2 > 0.995), with mean intra- and inter-assay variation coefficients of 2.88 % and 4.23 %, respectively. Recoveries ranged from 95 % to 101 %, limits of detection from 0.009 to 0.068 μmol/L, and limits of quantification from 0.031 to 0.187 μmol/L. Plasma mean concentrations were 3.18 ± 0.73 μmol/L for TMAO, 3.99 ± 0.65 μmol/L for DMG, 9.84 ± 2.08 μmol/L for CHOL, 24.22 ± 6.19 μmol/L for TMG, 0.54 ± 0.22 μmol/L for gBB, 57.29 ± 8.89 μmol/L for CAR, 1.10 ± 0.42 μmol/L for ERT, and 0.40 ± 0.11 μmol/L for TML. Significant inter-individual variability (mean RSD% of 26 %) was observed. Conclusion: The developed LC-MS/MS method enables rapid, sensitive, and selective quantification of TMAO and its precursors in human plasma. The analytical performance supports its application in clinical and metabolomic studies, contributing to a better understanding the role of TMAO in disease states
Caratterizzazione della distribuzione della coppia ergotioneina/ercinina e valutazione delle potenzialità dell’ercinina quale marker delle attività redox dell’ergotioneina
No full textGiven that redox activity of ergothioneine might explain the presence of hercynine in biological fluids, measurement of hercynine might serve to indirectly detect oxidative stress states or other biological processes involving ergothioneine. This could be particularly advantageous as the peculiar redox behavior of ergothioneine, which acts to rapidly restore ergothioneine concentrations, can minimize its potential fluctuations. Little is known about this betaine of the histidine in the body, which is in part due to the lack of reliable analytical methods and the difficulty in purchasing commercial standards. Following in-house chemical synthesis of hercynine and considering different analytical strategies, a LC-MS/MS method was developed for the measurement of hercynine levels in different animal and human specimens such as whole blood, plasma/serum, urine, and equine seminal plasma. The results of these analyses highlight the uncertain role of hercynine as an indirect marker of ergothioneine activities in humans. This was primarily due to the challenges with the identification of specific phenotypes where ergothioneine plays a clear biological role. Conversely, due to the unusual physiology of stallions’ sperm cells, who rely primarily on mitochondrial ATP production by oxidative phosphorylation rather than glycolysis, hercynine can serve as an indirect marker of ergothioneine in stallions’ seminal plasma
B-Type Natriuretic Peptide Concentrations, COVID-19 Severity, and Mortality: A Systematic Review and Meta-Analysis With Meta-Regression
No full textAlterations in cardiac biomarkers have been reported in patients with coronavirus disease 2019 (COVID-19) in relation to disease severity and mortality. We conducted a systematic review and meta-analysis with meta-regression of studies reporting B-type natriuretic peptide (BNP) or N-terminal proBNP (NT-proBNP) plasma concentrations in COVID-19. We searched PubMed, Web of Science, and Scopus, between January 2020 and 2021, for studies reporting BNP/NT-proBNP concentrations, measures of COVID-19 severity, and survival status (PROSPERO registration number: CRD42021239190). Forty-four studies in 18,856 COVID-19 patients were included in the meta-analysis and meta-regression. In pooled results, BNP/NT-proBNP concentrations were significantly higher in patients with high severity or non-survivor status when compared to patients with low severity or survivor status during follow up (SMD = 1.07, 95% CI: 0.89-1.24, and p < 0.001). We observed extreme between-study heterogeneity (I-2 = 93.9%, p < 0.001). In sensitivity analysis, the magnitude and the direction of the effect size were not substantially modified after sequentially removing individual studies and re-assessing the pooled estimates, (effect size range, 0.99 - 1.10). No publication bias was observed with the Begg's (p = 0.26) and Egger's (p = 0.40) t-tests. In meta-regression analysis, the SMD was significantly and positively associated with D-dimer (t = 2.22, p = 0.03), myoglobin (t = 2.40, p = 0.04), LDH (t = 2.38, p = 0.02), and procalcitonin (t = 2.56, p = 0.01) concentrations. Therefore, higher BNP/NT-proBNP plasma concentrations were significantly associated with severe disease and mortality in COVID-19 patients
A capillary electrophoresis UV detection-based method for global genomic DNA methylation assessment in human whole blood
No full textQuantitative analysis of DNA methylation patterns is of special importance in several developmental and pathological situations. The development of simple and robust methods to assess DNA methylation is required to facilitate its measurement and interpretation in clinical practice. We describe a highly reproducible CE-UV method for the separation and detection of cytosine and methylcytosine, after formic acid hydrolysis of DNA extracted from human whole blood. Hydrolyzed samples were dried and successively dissolved with water and then injected into the capillary without sample derivatization procedures. The use of a run buffer containing 50 mmol/L BIS-TRIS propane (BTP) phosphate buffer at pH 3.25 and 60 mmol/L sodium acetate buffer at pH 3.60 (4:1, v/v) allowed a baseline analytes separation within 12 min. Precision tests indicated an elevated reproducibility with an inter-assay CV of 1.98%
Analytical Insights into Methods for Measuring Ischemia-Modified Albumin
No full textIschemia-modified albumin (IMA) has emerged as a pivotal biomarker for the early detection of ischemic conditions, particularly myocardial ischemia, where timely diagnosis is crucial for effective intervention. This review provides an overview of the analytical methods for assessment of IMA, including Albumin Cobalt Binding (ACB), Albumin Copper Binding (ACuB), Enzyme-Linked Immunosorbent Assay (ELISA), new techniques such as liquid crystal biosensors (LCB), quantum dot coupled X-ray fluorescence spectroscopy (Q-XRF), mass spectrometry (MS), and electron paramagnetic resonance (EPR) spectroscopy. Each method was thoroughly examined for its analytical performance in terms of sensitivity, specificity, and feasibility. The ACB assay is the most readily implementable method in clinical laboratories for its cost-effectiveness and operational simplicity. On the other hand, the ACuB assay exhibits enhanced sensitivity and specificity, driven by the superior binding affinity of copper to IMA. Furthermore, nanoparticle-enhanced immunoassays and liquid crystal biosensors, while more resource-intensive, significantly improve the analytical sensitivity and specificity of IMA detection, enabling earlier and more accurate identification of ischemic events. Additionally, different biological matrices, such as serum, saliva, and urine, were reviewed to identify the most suitable for accurate measurements in clinical application. Although serum was considered the gold standard, non-invasive matrices such as saliva and urine are becoming increasingly feasible due to advances in technology. This review underscores the role of IMA in clinical diagnostics and suggests how advanced analytical techniques have the potential to significantly enhance patient outcomes in ischemic disease management
Symmetric dimethylarginine, high-density lipoproteins, and cardiovascular risk assessment: are we ready for clinical use?
No full textNew horizons in arginine metabolism, ageing and chronic disease states
No full textThe elucidation of the metabolic pathways of the amino acid arginine and their role in health and disease have been an intensive focus of basic and clinical research for over a century. The recent advent of robust analytical techniques for biomarker assessment in large population cohorts has allowed the investigation of the pathophysiological role of specific arginine metabolites in key chronic disease states in old age, particularly those characterised by a reduced synthesis of endothelial nitric oxide, with consequent vascular disease and atherosclerosis. Two arginine metabolites have been increasingly studied in regard to their potential role in risk stratification and in the identification of novel therapeutic targets: the methylated arginine asymmetric dimethylarginine (ADMA) and the arginine analogue homoarginine. Higher circulating concentrations of ADMA, a potent inhibitor of nitric oxide synthesis, have been shown to predict adverse cardiovascular outcomes. By contrast, there is emerging evidence that homoarginine might exert cardioprotective effects. This review highlights recent advances in the biological and clinical role of ADMA and homoarginine in cardiovascular disease and other emerging fields, particularly chronic obstructive pulmonary disease, dementia, and depression. It also discusses opportunities for future research directions with the ultimate goal of translating knowledge of arginine metabolism, and its role in health and disease, into the clinical care of older adults
Higher scores of the Kessler Psychological Distress Scale (K10) are associated with lower serum ergothioneine and higher serum asymmetric dimethyl-l-arginine concentrations in a cohort of middle-aged and older adults
No full textA diethylpyrocarbonate-based derivatization method for the LC-MS/MS measurement of plasma arginine and its chemically related metabolites and analogs
No full textBackground: Changes in NO metabolism correlate with cardiovascular risk factors and are associated with endothelial dysfunction. NO availability is regulated by nitric oxide synthase (NOS) and arginine and some chemically related metabolites and analogs have the capacity to alter NOS activity. Hence the need for analytical methods for the simultaneous assessment of these analytes. Methods: Analytes (L-arginine (Arg), N G -monomethyl-L-arginine (MMA), L-homoarginine (hArg), asymmetric dimethyl-L-arginine (ADMA), symmetric dimethyl-L-arginine (SDMA), and L-citrulline (CIT)) were isolated from human plasma by thermal coagulation of plasma followed by a derivatization with diethylpyrocarbonate. Carbetoxy derivatives were separated on a C18 reversed-phase column in <10 min using an aqueous solution of 0.4% v/v formic acid and acetonitrile (95:5, v/v) mixture as a mobile phase. Positive electrospray ionization and tandem mass spectrometry in combination with specific multiple reaction monitoring transitions were used for detection of analytes and three deuterated forms of the analytes used as internal standards. Results: Intra- and inter-day precision %RSD values ranged between 3 and 5.5% and percentage recoveries were close to 100% for all analytes. Plasma concentrations in 20 healthy male volunteers were 58.62 ± 8.81 μmol/L for Arg, 105.08 ± 21.66 nmol/L for MMA, 1.88 ± 0.57 μmol/L for hArg, 0.612 ± 0.140 μmol/L for ADMA, 0.581 ± 0.172 μmol/L for SDMA, and 28.62 ± 11.60 μmol/L for Cit, respectively. Conclusion: This LC–MS/MS method provides the capacity to quantify the plasma concentrations of arginine and some of its chemically related metabolites. Sample preparation was simple, inexpensive and effortless. Overall, given the short sample preparation and chromatographic run time, the method may be suitable for the fast and reproducible quantitative determination of the analytes in large clinical trials and routine analysis
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