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Long chain unsaturated fatty acids (LCUFAs) are emerging as critical contributors to inflammation and its resolution. Sensitive and accurate measurement of LCUFAs in biological samples is thus of great value in disease diagnosis and prognosis. In this work, a fluorous-derivatization approach for UPLC-MS/MS quantification of LCUFAs was developed by employing a pair of fluorous reagents, namely 3-(perfluorooctyl)-propylamine (PFPA) and 2-(perfluorooctyl)-ethylamine (PFEA). With this method, the LCUFAs in biological samples were perfluoroalkylated with PFPA and specifically retained on a fluorous-phase LC column, which largely reduced matrix interferences-induced quantitation deviation. Moreover, PFEA-labeled LCUFAs standards were introduced as one-to-one internal standards to farthest ensure unbiased results. Application of the proposed method enabled a reliable determination of eight typical LCUFAs with high sensitivity (LLOQ ranged from 30 amol to 6.25 fmol) and low matrix interferences (almost less than 10%). Such a high sensitivity could facilitate the determination of small-volume and low-concentration bio-samples. Further metabolic characterization of these targeted LCUFAs was monitored in OVA-induce asthma mice, requiring only 5 μL serum sample. Our results showed that asthmatic attack led to significant disturbances not only in the concentrations but also in the ratio among these LCUFAs. In view of the favorable advantages in sensitivity and accuracy, the present fluorous-paired derivatization approach will be expected to serve as a new avenue for dissecting the physiological and clinical implications of LCUFAs, thereby shedding light on the management of diseases related to their disturbances. Image 1 • A pair of fluorous reagents was employed for profiling of LCUFAs. • Matrix effects were largely reduced by the specific fluorophilicity between fluorinated-LCUFAs. • PFEA-labeled LCUFAs standards were used as one-to-one ISs to farthest ensure unbiased results. • An extreme low detection limit was achieved at an atto-molar level. [ABSTRACT FROM AUTHOR]

• Unidirectional inversion of ibuprofen enantiomers in Chinese neonates is unclear. • High-throughput UHPLC-MS/MS method to determine ibuprofen enantiomers. • Unexpected pharmacokinetics profile of rac -ibuprofen in Chinese preterm neonates with PDA. Persistent patent ductus arteriosus (PDA) is generally observed in preterm neonates. Oral ibuprofen is the standard treatment for closing PDA in China. To investigate the chiral pharmacokinetics of ibuprofen enantiomers in Chinese premature infants with PDA, a simple, fast, and sensitive analytical enantioselective technology was developed with ultra-performance liquid chromatography (UPLC) – tandem mass spectrometry (MS/MS). Chromatographic separation of (R)-ibuprofen and (S)-ibuprofen was accomplished on a Lux® 3 µm Cellulose-3 (150 mm × 2.0 mm, 3 μm) at a flow rate of 0.2 mL/min within 6 min. UPLC separation was achieved by isocratic elution with a mobile phase consisting of formic acid:water (75:1000000, v/v) and acetonitrile:methanol (1:1, v/v). Only 50 µL of plasma samples were pre-treated with acetonitrile precipitation. Ibuprofen-d 3 was used as an internal standard. The standard curves of both enantiomers were linear over a concentration range of 0.0500 μg/mL to 50.00 μg/mL. The method has been validated for selectivity, carryover effect, lower limit of quantification, precision, accuracy, matrix effect, extraction recovery, dilution integrity, and stability based on the existing guidelines of the National Medical Products Administration, the United States Food and Drug Administration, and the European Medicines Agency. This method has been successfully applied to investigate the pharmacokinetics of ibuprofen enantiomers in 9 preterm infants with PDA. Our results showed that a high chiral inversion ratio of (R)- to (S)-ibuprofen exists in Chinese preterm neonates. Further studies should be conducted to monitor drug concentration following oral administration of ibuprofen and to consider the effect of individual variations and ethnic differences in metabolizing enantiomers of ibuprofen in premature neonates with PDA. [ABSTRACT FROM AUTHOR]

• A UPLC–MS/MS method for quantitative analysis of valsartan, sacubitril and its major metabolite in human plasma, urine and peritoneal dialysis fluid were developed and validated. • This is the first report on a UPLC–MS/MS method for the simultaneous determination of valsartan, sacubitril and LBQ657 concentration in peritoneal dialysis fluid. • This method allowed to better characterize the pharmacokinetic of sacubitril/ valsartan in peritoneal dialysis patients with end-stage renal disease and provided evidence that peritoneal dialysis had an effect on the clearance of sacubitril/valsartan. Sacubitril/valsartan was indicated for the treatment of heart failure and hypertension in patients with end-stage renal disease on peritoneal dialysis therapy. Herein, a rapid, sensitive and robust method based on ultra-liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) was developed and validated for the determination of the concentrations of valsartan, sacubitril and its major metabolite LBQ657 in plasma, urine and peritoneal dialysis fluid. Samples were extracted from various biological fluids using protein precipitation. Extracts were subjected to UPLC–MS/MS with electrospray ionization in positive-ion mode. The developed method was fully validated over a concentration range of 8.00–8000 ng/mL for valsartan, 2.00–2000 ng/mL for sacubitril and 30.0–30,000 ng/mL for LBQ657 in plasma, 2.00–1000 ng/mL for valsartan, 1.00–500 ng/mL for sacubitril and 20.0–10000 ng/mL for LBQ657 in urine, and 0.200–100 ng/mL for valsartan, 0.0400–20.0 ng/mL for sacubitril and 2.00–1000 ng/mL for LBQ657 in peritoneal dialysis fluid. The intra- and inter-day precisions for all analytes in various matrices were less than 12.3%, and the intra- and inter-day accuracies results were all between 88.0% and 109.2%. All analytes were stable for at least 8 h at room temperature (25°C), five freeze–thaw cycles, and 37 days at −40°C and −80°C in plasma, urine and peritoneal dialysis fluid. In conclusion, this developed method is reliable, sensitive and specific for determining the concentrations of valsartan, sacubitril and LBQ657 in plasma, urine and peritoneal dialysis fluid. The assay was available to pilot the pharmacokinetics study of sacubitril/valsartan in patients with end-stage renal disease on peritoneal dialysis, and it could provide evidence that peritoneal dialysis had an effect on the clearance of sacubitril/valsartan. [ABSTRACT FROM AUTHOR]

• A sensitive and robust UPLC–MS/MS method for simultaneous quantification of lidocaine, monoethylglycinexylidide (MEGX) and glycinexylidideme (GX) in human plasma was developed and fully validated. • A simple one-step protein precipitation method was used for the pretreatment of plasma sample. • The fully validated UPLC–MS/MS method was successfully applied to the clinical pharmacokinetics study of lidocaine in liver cancer patients undergoing laparoscopic hepatectomy. • Our results demonstrated that the reasons why the metabolism of lidocaine and MEGX were slightly prolonged might be related to the duration of hepatic blood flow occlusion. Lidocaine, widely used as a local anesthetic, has anti-inflammatory and inhibitory effects on tumor recurrence and metastasis. To investigate the pharmacokinetics of lidocaine in liver cancer patients undergoing laparoscopic hepatectomy, a fast and sensitive analytical technique was developed. The method was adequately validated with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS) to simultaneously determine the concentration of lidocaine and its metabolites in plasma. The chromatographic separation was achieved on an Acquity UPLC BEH C 18 column (2.1 × 50 mm, 1.7 µm) by gradient elution with a mobile phase of A (formic acid–water (1:1000, v/v)) and B (formic acid-acetonitrile (1:1000, v/v)). The accuracy and precision were verified within the concentration ranges of 10–5000 ng/mL for lidocaine, 2–1000 ng/mL for monoethylglycinexylidide (MEGX) and 2–500 ng/mL for glycinexylidide (GX). The selectivity, carry-over effect, interference between the analytes and internal standard (IS), precision and accuracy, matrix effect extraction recovery, dilution integrity and stability were satisfactory for the relevant guideline standards. The method was successfully applied to the pharmacokinetic study of lidocaine in liver cancer patients undergoing laparoscopic hepatectomy. After receiving a bolus and continuous infusion, the mean peak concentration of lidocaine was 2097 ng/mL for lidocaine, 336.6 ng/mL for MEGX and 72.66 ng/mL for GX, respectively. The mean peak time was 2.89 h for lidocaine, 5.14 h for MEGX and 9.88 h for GX, respectively. In addition, the mean half-life was 4.19 h for lidocaine and 6.92 h for MEGX. In this study, we found that the metabolism of lidocaine and MEGX might be affected by the hepatic blood flow occlusion or liver injury. [ABSTRACT FROM AUTHOR]

SY-007 is an interfering peptide designed to disrupt the cell death signaling of phosphatase and tensin homolog deleted on chromosome ten (PTEN) nuclear translocation during ischemic stroke. Preclinical studies indicated that rats treated with 1.5 mg/kg SY-007 in the middle cerebral artery occlusion (MACO) model had significantly reduced stroke lesion size even when administered 6 h after the stroke onset. The aim of this study was to evaluate the safety, tolerability, and pharmacokinetics of ascending doses of SY-007 administered intravenously in healthy Chinese subjects. A total of 78 healthy Chinese subjects were enrolled in the single ascending dose study (1–60 mg) and received a 15-min intravenous infusion SY-007 or placebo. Plasma concentrations of SY-007 were measured by a validated liquid chromatography-tandem mass spectrometry method. Pharmacokinetic parameters were determined using non-compartmental and compartment analyses. A model based on target-mediated drug disposition was applied. Model evaluation was performed through visual predictive checks and bootstrap analysis. Across doses of 1–60 mg, SY-007 was well tolerated. All adverse events (AEs) were mild or moderate in intensity, and all resolved without intervention. After infusion, SY-007 plasma concentrations decreased quickly with the mean terminal half-life was shorter than 0.78 h. The area under the concentration-time curve increased with a greater than dose-dependent manner from 1 to 30 mg and resulted in a dose-dependent increased from 30 to 60 mg. The nonlinear phenomenon was well described by a simplified target-mediated drug disposition (TMDD) model. Intravenous dosing of SY-007 appears to be safe up to a dose of 60 mg. Nonlinear pharmacokinetics was observed across the evaluated doses and TMDD might be the primary reason. The effective dose of SY-007 for neuroprotective effect in patients with ischemic stroke is expected to be 10–30 mg and was recommended for the later multiple ascending dose study of SY-007. Clinicaltrials.gov: NCT04111523. [Display omitted] [ABSTRACT FROM AUTHOR]

There is presently no efficient dose individualization strategy for the use of antiseizure medications in epileptic pregnant patients. This study aimed to develop a population pharmacokinetics model for levetiracetam and propose a tailored adaptive individualized dosage strategy for epileptic pregnant patients. A total of 322 levetiracetam plasma concentrations from 238 patients with epilepsy were included, including 216 women with epilepsy (20.83% of whom were pregnant). The levetiracetam plasma concentration was measured using a validated ultra-performance liquid chromatography-tandem mass spectrometry assay, and the data were modeled using a nonlinear mixed-effects model. The resultant model served as the basis for simulating the dosage adjustment strategy. A one-compartment model with first-order elimination best described the pharmacokinetic data of levetiracetam. The apparent clearance (CL/F) was 3.43 L/h (95% CI 3.30–3.56) and the apparent volume of distribution was 43.7 L (95% CI 40.4–47.0) for a typical individual of 57.2 kg. Pregnancy and body weight were found to be significant covariates of CL/F of levetiracetam. The recommended regimen of levetiracetam could be predicted by the population pharmacokinetic model based on body weight, gestational age, and the daily dose of levetiracetam taken before pregnancy. [ABSTRACT FROM AUTHOR]

Liquid chromatography-mass spectrometry based profiling of microbial metabolites has been a challenging task due to their diverse physicochemical properties and wide concentration ranges. This study is aimed to develop a systematic platform for the broad-scale profiling of microbial metabolites by integrating aqueous-lipophilic biphasic extractions and chemical derivatizations with a data-dependent automatable metabolite annotation algorithm. This complementary strategy of detection will not only largely expand the metabolite coverage, but also facilitate the drawing out of interested submetabolome using designed chemical derivatizations. Then, the data-dependent metabolite annotation algorithm is able to automatically match the raw MS/MS data with those of compounds in the self-collected databases. The performance of this platform is illustrated through the analysis of two representative bacteria (Escherichia coli and Pseudomonas aeruginosa) and intestinal contents samples from experimental colitis mice. As a result, 292 metabolites corresponding to 875 annotated features distributing over 25 chemical families were putatively annotated in a short time. Of these metabolites, 197 and 218 are respectively from the bacteria and intestinal contents, and 107 are identified in all three biological samples. This systematic platform could be used to accomplete high-coverage detection and high-quality data processing of microbial metabolites. At the same time, chemical derivatization design and the establishment of self-collected databases will facilitate self-driven untargeted analysis. Image 1 • Self-collected MS/MS database of microbial metabolites is established. • Microbial metabolites are detected by integrating aqueous-lipophilic biphasic extractions with chemical derivatizations. • Data-dependent automatable metabolite annotation package is developed for annotation of raw MS/MS data. • This platform gives a support to characterize microbial metabolites in biosamples. [ABSTRACT FROM AUTHOR]

There are well demonstrated differences in tumor cell metabolism between right sided (RCC) and left sided (LCC) colon cancer, which could underlie the robust differences observed in their clinical behavior, particularly in metastatic disease. As such, we utilized liquid chromatography-mass spectrometry to perform an untargeted metabolomics analysis comparing frozen liver metastasis (LM) biobank samples derived from patients with RCC (N = 32) and LCC (N = 58) to further elucidate the unique biology of each. We also performed an untargeted RNA-seq and subsequent network analysis on samples derived from an overlapping subset of patients (RCC: N = 10 ; LCC: N = 18). Our biobank redemonstrates the inferior survival of patients with RCC-derived LM (P = 0.04), a well-established finding. Our metabolomic results demonstrate increased reactive oxygen species associated metabolites and bile acids in RCC. Conversely, carnitines, indicators of fatty acid oxidation, are relatively increased in LCC. The transcriptomic analysis implicates increased MEK-ERK, PI3K-AKT and Transcription Growth Factor Beta signaling in RCC LM. Our multi-omic analysis reveals several key differences in cellular physiology which taken together may be relevant to clinical differences in tumor behavior between RCC and LCC liver metastasis. • First integrated metabolomics characterization of right colon liver metastases. • Increased ROS, bile acids and TGF-B signaling in right colon liver metastases. • Potential mechanisms of EGFR-inhibitor resistance in right colon liver metastases. [ABSTRACT FROM AUTHOR]

To identify gingival recession-related biomarkers in orthodontic patients, we compared the proteome of gingival crevicular fluids (GCF) from healthy gingiva without orthodontic treatment (GH), healthy gingiva undergoing orthodontic treatment (OGH), and recessed gingiva undergoing orthodontic treatment (OGR). GCF samples were obtained from the anterior teeth of 15 volunteers (n = 5/group). Quantitative proteomic analysis was performed using DIA-based liquid chromatography-tandem mass spectrometry (LC-MS/MS). Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were used to annotate differentially expressed proteins (DEPs). Receiver-operating characteristic (ROC) analysis was performed to detect and filter biomarker candidates, while Protein-Protein Interaction (PPI) Networks were utilized to determine the interactions between these DEPs. A total of 253, 238, and 101 DEPs were found in OGR vs. OGH, OGR vs. GH, and OGH vs. GH groups, respectively. Based on the Venn diagram of three groups, 128 DEPs in OGR vs. OGH group were identified as specific proteins associated with progressive gingival recession (GR) during orthodontic treatment. Molecular function analysis showed that 128 DEPs were enriched in "molecular binding", including antigen binding, RNA binding, double-stranded RNA binding, cadherin binding involved in cell-cell adhesion, vinculin binding, S100 protein binding, and Ral GTPase binding. The majority of these DEPs were also involved in cytoskeletal regulation. In addition, biological process analysis showed an enrichment in translation, while cellular component analysis indicated that 128 DEPs were related to extracellular exosome. Furthermore, Ribosome and Phagosome were the top two terms in KEGG analysis. The results of ROC analysis demonstrated that 26 proteins could be potential biomarker candidates for GR. PPI networks analysis predicted that IQGAP1, ACTN1, TLN1, VASP, FN1, FERMT3, MYO1C, RALA, RPL35, SEC61G, KPNB1, and NPM1 could be involved in the development of GR via cytoskeletal regulation. In summary, we identified several GCF proteins associated with GR after orthodontic treatment. These findings could contribute to the prevention of GR in susceptible patients before the initiation of orthodontic treatment. Orthodontic patients with GR often report esthetic defects or root hypersensitivity during orthodontic treatment, especially at the anterior teeth site. GCF, rich in protein, is an easily accessible source of potential biomarkers for the diagnosis of periodontal diseases; however, little is known about the changes in GCF proteome associated with GR in orthodontic patients. In this study we firstly used DIA-based LC-MS/MS to evaluate the proteome and to identify the biomarker candidates for GR in orthodontic patients. These findings will improve our understanding of GR during orthodontic treatment, and could contribute to an earlier diagnosis, or even prevention, of GR in susceptible populations before orthodontic treatment. [Display omitted] • Orthodontic patients with progressive (GR have unique protein expression profile compared to subjects without GR. • Some orthodontic patients would be more susceptible to orthodontic force to result in GR. • Force-sensitive cytoskeleton-related proteins may be crucial moleculars to regulate alveolar bone remodeling and leading to GR. [ABSTRACT FROM AUTHOR]

The neural differentiation of embryonic stem cells (ESCs) is of great significance for understanding of the mechanism of diseases. Histone post-translational modifications (HPTMs) play a key role in the regulation of ESCs differentiation. Here, we combined the stable isotope chemical derivatization with nano-HPLC-mass spectrometry (MS) for comprehensive analysis and quantification of histone post-translational modifications (HPTMs) in mouse embryonic stem cells (mESCs) and neural progenitor cells (mNPCs) that was derived from ESCs. We identified 85 core HPTM sites in ESCs and 78HPTM sites in NPCs including some novel lysine modifications. Our quantitative analysis results further revealed the changes of HPTMs from ESCs to NPCs and suggested effect of combinational HPTMs in the differentiation. This study demonstrates that HPLC–MS-based quantitative proteomics has a considerable advantage on quantification of combinational PTMs and expands our understanding of HPTMs in the differentiation. [ABSTRACT FROM AUTHOR]