“…In detail, AKI patients showed increased levels of SDMA, Phe and Kyn/Trp ratio, with values of 0.2547~0.4962 μg/mL, 10.7692~23.9799 μg/mL and 0.0364~0.1093, respectively, but decreased levels of Trp and SDMA/SCr ratio, with values of 6.7584~13.8741 μg/mL and 0.9510~3.1014, respectively. Among the above mentioned, the levels of Ser and Lys in our study were lower than those reported in other studies 17 , 18 , which might be derived from different AKI status of patients or others. Figure 1 Investigated AA metabolic pathways and the potential biomarkers with their fold-changes in NA and NB groups.…”
Few literatures have evaluated the exact role of metabolomics in the identification process of potential biomarkers for acute kidney injury among the patients receiving renal transplantation. On top of this, the success of metabolomics in biomarker translation seems to lie in the robust quantitative method. As such, a single-center retrospective observational study was conducted enrolling 42 patients underwent renal transplantation with/without acute kidney injury, as well as 24 healthy volunteers, in Shanghai Changzheng Hospital. Plasma amino acid metabolic patterns for the participants were investigated by targeted UHPLC-MS/MS metabolic profiling. The most significant changes of the explored metabolites were related to the disturbance of tryptophan metabolism and arginine metabolism. Abnormal circulating tryptophan and symmetric dimethylarginine were identified to be potential biomarkers of acute kidney injury, combination of which showed a higher area under receiver-operator curve value (AUC = 0.901), improved sensitivity (0.889) and specificity (0.831) compared with creatinine only. Overall, these results revealed that targeted metabolomics analysis would be a potent and promising strategy for identification and pre-validation of biomarkers of acute kidney injury in renal transplantation patients.
“…In detail, AKI patients showed increased levels of SDMA, Phe and Kyn/Trp ratio, with values of 0.2547~0.4962 μg/mL, 10.7692~23.9799 μg/mL and 0.0364~0.1093, respectively, but decreased levels of Trp and SDMA/SCr ratio, with values of 6.7584~13.8741 μg/mL and 0.9510~3.1014, respectively. Among the above mentioned, the levels of Ser and Lys in our study were lower than those reported in other studies 17 , 18 , which might be derived from different AKI status of patients or others. Figure 1 Investigated AA metabolic pathways and the potential biomarkers with their fold-changes in NA and NB groups.…”
Few literatures have evaluated the exact role of metabolomics in the identification process of potential biomarkers for acute kidney injury among the patients receiving renal transplantation. On top of this, the success of metabolomics in biomarker translation seems to lie in the robust quantitative method. As such, a single-center retrospective observational study was conducted enrolling 42 patients underwent renal transplantation with/without acute kidney injury, as well as 24 healthy volunteers, in Shanghai Changzheng Hospital. Plasma amino acid metabolic patterns for the participants were investigated by targeted UHPLC-MS/MS metabolic profiling. The most significant changes of the explored metabolites were related to the disturbance of tryptophan metabolism and arginine metabolism. Abnormal circulating tryptophan and symmetric dimethylarginine were identified to be potential biomarkers of acute kidney injury, combination of which showed a higher area under receiver-operator curve value (AUC = 0.901), improved sensitivity (0.889) and specificity (0.831) compared with creatinine only. Overall, these results revealed that targeted metabolomics analysis would be a potent and promising strategy for identification and pre-validation of biomarkers of acute kidney injury in renal transplantation patients.
“…The use of a stable isotope‐labeled analyte spiked into the authentic matrix is also a typical strategy to quantify the endogenous compounds. However, the drawbacks of the surrogate analyte method is the limited availability of stable isotope‐labeled compounds for the internal standard, balancing responses between the authentic analyte and stable isotope‐labeled analyte and difficulty of diluting samples above the quantification limit . In addition, the authentic standard analyte spiked into the authentic matrix may be an alternative method.…”
We developed a highly sensitive and specific high-performance liquid chromatography with tandem mass spectrometry method with an atmospheric pressure chemical ionization interface to determine 24S-hydroxycholesterol, a major metabolite of cholesterol formed by cytochrome P450 family 46A1, in human plasma without any derivatization step. Phosphate buffered saline including 1% Tween 80 was used as the surrogate matrix for preparation of calibration curves and quality control samples. The saponification process to convert esterified 24S-hydroxycholesterol to free sterols was optimized, followed by liquid-liquid extraction using hexane. Chromatographic separation of 24S-hydroxycholesterol from other isobaric endogenous oxysterols was successfully achieved with gradient mobile phase comprised of 0.1% propionic acid and acetonitrile using L-column2 ODS (2 μm, 2.1 mm id × 150 mm). This assay was capable of determining 24S-hydroxycholesterol in human plasma (200 μL) ranging from 1 to 100 ng/mL with acceptable intra- and inter-day precision and accuracy. The potential risk of in vitro formation of 24S-hydroxycholesterol by oxidation from endogenous cholesterol in human plasma was found to be negligible. The stability of 24S-hydroxycholesterol in relevant solvents and human plasma was confirmed. This method was successfully applied to quantify the plasma concentrations of 24S-hydroxycholesterol in male and female volunteers.
“…Baseline enantioseparation for all proteinogenic AAs except for Pro, Arg and His was achieved. Cinchona alkaloid-based zwitterionic ion-exchange type enantioselective column, Chiralpak ZWIX(+) (for the structure see Figure 2 [73]. Phosphate buffered saline (PBS) was used as a surrogate matrix.…”
Section: Chromatographic Methods For Aa Determination In Biological Smentioning
Abstract:Occurrence of D-amino acids in living organisms is a useful indicator of various changes, diseases, or disorders. Determination of amino acid enantiomers, namely the enantiomeric ratio of amino acids or excess of certain D-amino acids, represents a useful tool in the studies of aging processes or biomarkers in disease/disorder diagnosis in humans. The amount of D-amino acids is usually very low. Therefore, suitable sample pretreatment, often derivatization, and highly selective and sensitive separation methods are essential for D-amino acid analysis in this field. Chromatographic techniques offer appropriate choices for solving these tasks. This review covers the advances in methodology and development of improved instrumental chromatographic methods focused on D,L-amino acid separation and determination. New findings in the area of possible D-amino acid biomarkers are also included.
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