Liquid Chromatography-tandem Mass Spectrometry Research Articles

Development of a rapid and robust hydrop interaction liquid chromatography tandem mass spectrometry method for the detection of 13 endogenous amino acids as well as trimethylamine oxide in serum and tissues of the mice.

This work aimed to establish an HILIC-MS/MS method to simultaneously determine the levels of 13 endogenous amino acids and trimethylamine oxide in the biological samples from the mice. Electrospray ion source was used for the analysis of mass spectrometry. The 20 min separation was applied in a Dikma Inspire Hilic column (2.1 × 100.0mm, 3μM). Positive ion mode under an MRM model gave a satisfying response value. The limits of quantitation were evaluated by accuracy from -12.59% to 7.89% and precision from 1.77% to 14.00% as well as acceptable interday and intraday precision, matrix effect, recovery, and stability. Later, the assay was successfully used to measure the concentrations of the determinands in the biological samples. Individual and tissue distribution differences for these metabolites were observable. The amino acids had a consistent highest content in the spleens, while the lowest levels were found in the livers. Alanine was the most abundant amino acid in the serum, and taurine kept the highest content in all of the tissues. Trimethylamine oxide remained low level, especially in the liver samples.

Method development, multi-residue determination, and dietary exposure risk assessment of plant growth regulators in homologous materials of medicine and food.

Residues of plant growth regulators (PGRs) in homologous materials of medicine and food threaten public health. This study aimed to develop a rapid, sensitive, and high-throughput method for simultaneously determining 16 PGR residues in homologous materials of medicine and food. Furthermore, the established method was applied to actual samples to assess the potential exposure risk of multi-PGR residues. A modified high-throughput quick, easy,cheap, effective, rugged, and safe (QuEChERS) method coupled with ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed and validated. The extraction solvent, type of extraction method, and subsequent purification techniques were investigated to achieve a better analysis of the target. Risk assessment was based on chronic dietary risk assessment. Ultrasonic extraction with 1% formic acid-acetonitrile was employed, and MgSO4 + NaAc was selected as the clean-up sorbent. The 16 PGRs showed a good linear relationship in the range of 1 ~ 200 μg/L (r ≥ 0.9960), with detection limits ranging from 0.3 to approximately 3 μg/kg. The recovery rate ranged from 65 to 109%, with RSD from 0.01 to 10% (n = 6). The total detection rate of 16 PGRs in the samples was 87%. The risk assessment indicated that the multi-residues of PGRs in homologous materials of medicine and food would not pose a potential risk to human health. This work provides a valuable reference for the monitoring of multiple PGRs. It has also improved our understanding of the possible exposure risk of PGR residues in homologous materials of medicine and food.

Metabolomic profiling reveals the step-wise alteration of bile acid metabolism in patients with diabetic kidney disease

BackgroundDiabetic kidney disease (DKD) is the major complication of diabetes concomitant with gut dysbiosis and glycometabolic disorder, which are strongly associated with bile acid (BA) metabolism. Yet studies investigating the BA metabolism involving in DKD pathogenesis are limited. This study aimed to explore the metabolomic profiling of BAs in DKD and analyze its association with DKD progression.MethodsAn ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established to quantify BAs in the plasma, fecal and urine samples of patients with DKD or T2DM and healthy individuals (n = 30 for each group). The key BAs associated with DKD were identified by orthogonal partial least-squares discriminant analysis (OPLS-DA) and receiver-operating characteristic (ROC) curve. Polynomial regression and Pearson’s correlation analyses were performed to assess the correlation between the key BAs and the clinical indicators reflecting DKD progression.ResultsMetabolomic profiling of 50 kinds of BAs presented the markedly step-wise alterations of BAs in plasma and feces as well as the little in urine of patients with DKD. Eight kinds of BAs in the plasma, eight kinds in the feces and three kinds in the urine were abnormally expressed, accompanying with the increased conjugated/unconjugated ratios of cholic acid, deoxycholic acid, chenodeoxycholic acid, ursodeoxycholic acid and hyocholic acid in the plasma, and of cholic acid, chenodeoxycholic acid and lithocholic acid in the feces. Moreover, the increased plasma level of glycochenodeoxycholic acid, and the increased fecal levels of glycolithocholic acid, 7-ketodeoxycholic acid and chenodeoxycholic acid-3-β-D-glucuronide are strongly correlated with the clinical indicators reflecting DKD progression, including eGFR, 24 h urinary protein and 24 h urinary microalbumin.ConclusionsOur study for the first time disclosed the specific alterations of BA metabolism reflecting the step-wise progression of DKD, providing the basis for early identification and therapeutical strategies for DKD.

Forced degradation behavior of tadalafil and macitentan by validated stability-indicating high performance liquid chromatography method and identification of degradation products by liquid chromatography tandem mass spectrometry

Forced degradation behavior of tadalafil and macitentan by validated stability-indicating high performance liquid chromatography method and identification of degradation products by liquid chromatography tandem mass spectrometry

Exploring serum bile acids as potential noninvasive biomarkers for nonalcoholic fatty liver disease

BackgroundBile acids are vital regulators of liver metabolism, and their dysregulation is closely linked with the progression of nonalcoholic fatty liver disease (NAFLD). Profiling these bile acids may provide valuable diagnostic and prognostic markers for these conditions. This study aimed to evaluate bile acid profiles in NAFLD patients and assess their potential as biomarkers for diagnosing and predicting disease progression. Serum levels of 14 bile acids were measured in 25 normal healthy controls (NHC), 35patients with metabolic dysfunction–associated steatotic liver disease (MASLD), and 40 patients with NASH, categorized by the NAFLD Activity Score (NAS). Quantification was performed using high-performance liquid chromatography-tandem mass spectrometry (HPLC–MS/MS).ResultsPrimary unconjugated bile acids, CA and CDCA, along with conjugated acids GCA, GCDCA, TCA, and TCDCA, were significantly elevated in both MASLD and NASH compared to NHC (all p < 0.05). While levels increased progressively from NHC to MASLD to NASH, no significant differences were observed between MASLD and NASH except for GCA and TCA (P < 0.05). Similarly, secondary bile acids LCA, TLCA, GUDCA, and TUDCA were higher in MASLD and NASH compared to NHC (all p < 0.05).Logistic regression identified CA (odds ratio = 2.05, p = 0.02), CDCA (odds ratio = 1.58, p = 0.04), GCA (odds ratio = 1.92, p = 0.03) and DCA (odds ratio = 2.06, p = 0.04) as significant predictors of fibrosis. For active inflammation, GCA (odds ratio = 2.04, p = 0.04), and TCA (odds ratio = 1.94, p = 0.04) were significant predictors. In steatosis, CA, CDCA, GCA, DCA, TDCA, TLCA, and UDCA were notable predictors, with high odds ratios.ConclusionThe study highlights significant alterations in bile acid profiles associated with NAFLD progression. Specific bile acids, such as CA, GCA, TCA, and TCDCA are strong predictors of disease severity, indicating their potential as biomarkers for NAFLD treatment and prognosis.

Propofol and Fentanyl Pharmacokinetics and Pharmacodynamics in Extracorporeal Membrane Oxygenation.

Despite the potential risks associated with sedation, there is a paucity of pharmacokinetic/pharmacodynamic (PK/PD) data for propofol and fentanyl in patients supported with veno-venous extracorporeal membrane oxygenation (V-V ECMO). Describe propofol and fentanyl PK/PD profiles in V-V ECMO patients. Prospective, single-center, open-label PK/PD study at the Toronto General Hospital ICU between July 2022 and January 2023. Using high-performance liquid chromatography-tandem mass spectrometry, propofol and fentanyl total concentrations were measured during V-V ECMO. Sequential PK/PD modeling, using sex as a covariate, was conducted with processed electroencephalography (PSI) for sedation, and expiratory occlusion pressure (Pocc), and airway occlusion pressure during the first 0.1 seconds (P0.1) for respiratory effort. Eleven patients underwent 106 evaluations over a median (IQR) follow-up of 146 (116-146) hours. Patient's average (±SD) age was 43 (±13) years, and 55% were female. Propofol and fentanyl PK were best described by a two-compartment model. Propofol-PSI PD was described using an effect compartment, with a coefficient of determination (ρ2) of 0.78. There was a significant increase in propofol (p=0.01) and fentanyl (p=0.03) clearance within 10 minutes of ECMO initiation, plateauing after 8 hours of ECMO support. Despite this, patient over-sedation (PSI<40) occurred in 74% of the observations. Females exhibited higher sedative central volume of distribution and lower propofol clearance. ECMO initiation resulted in a time-limited increased sedative clearance. PSI accurately described sedative PD, but variable respiratory effort was observed irrespective of sedative plasma concentrations. Sex-based differences were found in sedative PK/PD parameters.

Impaired 11β-hydroxysteroid dehydrogenase type 2 activity in kidney disease disrupts 11-oxygenated androgen biosynthesis.

11-oxygenated androgens are a group of adrenal-derived steroids that require peripheral activation. In vitro data highlight a putative role for 11β-hydroxysteroid dehydrogenase type 2 (HSD11B2) in 11-oxygenated androgen biosynthesis, converting 11β-hydroxyandrostenedione (11OHA4) to 11-ketoandrostenedione (11KA4), the direct precursor of the potent androgen 11-ketotestosterone (11KT). As the kidney is the major site of HSD11B2 expression, we hypothesized that patients with chronic kidney disease (CKD) would have reduced 11-oxygenated androgen biosynthesis due to impaired HSD11B2 activity. To determine the role of HSD11B2 in 11-oxygenated androgen biosynthesis using a human CKD cohort alongside complementary cell culture and computational modeling approaches. Cross-sectional observational study of patients with CKD (n=85) and healthy controls (n=46) measuring serum and urinary concentrations of glucocorticoids, classic and 11-oxygenated androgens by liquid chromatography-tandem mass spectrometry. A computational model of peripheral 11-oxygenated androgen biosynthesis was fitted to the serum data to calculate relative HSD11B2 expression levels for each participant. HSD11B2 activity declined with eGFR, evidenced by higher cortisol (F)/cortisone (E) ratios in CKD patients compared to controls (p<0.0001). Serum concentrations of E, 11KA4, 11KT and 11β-hydroxytestosterone were lower in patients with CKD compared to controls (p<0.0001 for each). A computational model based on enzyme kinetic parameters of HSD11B2, 11β-hydroxysteroid dehydrogenase type 1, 17β-hydroxysteroid dehydrogenase type 2 and aldo-keto reductase 1C3 confirmed HSD11B2 as the key enzyme responsible for reduced 11-oxygenated androgen biosynthesis in CKD. Predicted HSD11B2 expression correlated with eGFR. This is the first in vivo study to confirm a central role for renal HSD11B2 in 11-oxygenated androgen biosynthesis. Determining the clinical implications of this observation for patients with CKD requires further research.

Therapeutic drug monitoring of linezolid in Chinese premature neonates: a population pharmacokinetic analysis and dosage optimization.

This study aimed to develop a pharmacokinetic model of linezolid in premature neonates and evaluate and optimize the administration regimen. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to detect the blood concentration data of 54 premature neonates after intravenous administration of linezolid, and the relevant clinical data were collected. The population pharmacokinetic (PPK) model was established by nonlinear mixed effects modeling. Based on the final model parameters, the optimal administration regimen of linezolid in premature neonates with different body surface areas (BSA) was simulated and evaluated. The pharmacokinetic properties of linezolid in premature neonates are best described by a single-compartment model with primary elimination. The population typical values for apparent volume of distribution and clearance were 0.783 L and 0.154 L/h, respectively. BSA was a statistically significant covariate with clearance (CL) and volume of distribution (Vd). Monte Carlo simulations showed that the optimal administration regimen for linezolid in premature neonates was 6 mg/kg q8h for BSA 0.11 m2, 7 mg/kg q8h for BSA 0.13 m2, and 9 mg/kg q8h for BSA 0.15 m2 with minimum inhibitory concentration (MIC) ≤1 mg/L, 7 mg/kg q8h for BSA 0.11 m2, 8 mg/kg q8h for BSA 0.13 m2, and 10 mg/kg q8h for BSA 0.15 m2 with MIC = 2 mg/L. A pharmacokinetic model was developed to predict the blood concentration on linezolid in premature neonates. Based on this model, the optimal administration regimen of linezolid in premature neonates needs to be individualized according to different BSA levels.

Identification of metabolomic changes and potential therapeutic targets during ovarian aging.

To reveal the metabolic differences of follicle fluid (FF) and granulosa cell (GC) between younger women and advanced age women in ART cycles, and then find potential therapeutic targets of ovarian aging. Forty-five patients were included in the study and they were divided into three groups according to their age (Group A: 20-30 years old; Group B: 30-35 years old; Group C: 35-45 years old). All patients underwent controlled ovarian stimulation using the follicular phase long-acting protocol, FF and GC were obtained 36-38 hours after HCG administration. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for metabolomics analysis and metabolic pathway analysis (MetPA) was utilized to find related pathways. Between group A and group C, there were 72 and 21 differential metabolites in FF and GC, respectively. KEGG enrichment analysis showed six pathways were co-enriched by the differential metabolites of FF and GC. Among them, we noticed that in the pathway GABAergic synapse, GABA (gamma-aminobutyric acid) was down-regulated in GC, while its downstream metabolite succinic acid was down-regulated in FF. Further ROC curve analysis was performed on these two metabolites, and the results showed that they all had a favorable predictive value. This study indicated that GABA and succinic acid could be potential therapeutic targets for ovarian aging, GABA may delay ovarian aging and improve ovarian function through its antioxidant properties, which may be a future direction of clinical treatment.

Multi-platform metabolic profiling of the stages of production of locally made lambanog, a traditional Philippine alcoholic beverage

Traditional alcoholic beverages contain a diverse range of metabolites that determine their taste and aroma profiles, as well as potential health benefits and possible toxicities. Furthermore, the metabolite levels can vary with the growing conditions of the raw materials and the production process, giving distinct profiles to products from different sources. Thus, the profiling of metabolites present in traditional alcoholic beverages is important for quality control, safety, and authentication purposes. In this study, the various metabolites that can be found in lambanog, a traditional Filipino coconut wine, are profiled using a multi-platform approach, together with the raw material and intermediates across the production process. Proton nuclear magnetic resonance (1H NMR) spectroscopy, liquid chromatography–mass spectrometry (LC–MS), and gas chromatography–mass spectrometry (GC–MS), were used to tentatively identify the metabolites present in samples from the different stages of lambanog production. 1H NMR spectroscopy has revealed the presence of ethanol, pyruvate, uracil, and sugars such as glycerol, fructose, mannitol, and glucose. GC–MS studies revealed potential compounds that may influence organoleptic properties in the different stages of lambanog production. Identifying and monitoring the identified metabolite components along the production process can aid future product and process developments, quality control, and authentication of lambanog and other traditional alcoholic beverages.

Proteomic analysis of plasma exosomes in patients with metastatic colorectal cancer

BackgroundThe diagnosis and treatment of colorectal cancer (CRC), especially metastatic colorectal cancer (mCRC), is a major priority and research challenge. We screened for expression differences in the plasma exosomal proteomes of patients with mCRC, those with CRC, and healthy controls (HCs) to discover potential biomarkers for mCRC.MethodsPlasma samples from five patients with mCRC, five patients with CRC, and five HCs were collected and processed to isolate exosomes by ultracentrifugation. Exosomal protein concentrations were determined using the BCA kit, and liquid chromatography-mass spectrometry was utilized to identify and analyze the proteins.ResultsFrom the exosomes isolated from plasma samples, a total of 994 quantifiable proteins were detected, including 287 differentially expressed proteins identified by quantitative proteomics analyses. Totals of 965, 963 and 968 proteins were identified in mCRC patients, CRC patients, and HCs, respectively. The study identified 83 proteins with differential expression in the plasma exosomes of mCRC patients. The top 10 upregulated proteins in the mCRC group and CRC groups were ITGA4, GNAI1, SFTPA2, UGGT1, GRN, LBP, SMIM1, BMP1, HMGN5, and MFAP4, while the top 10 downregulated proteins were PSMB8, LCK, RAB35, PSMB4, CD81, CD63, GLIPR2, RAP1B, RAB30, and CES1. Western Blot validation data confirmed that ITGA4 and GNAI1 were unequivocally enriched in plasma-derived exosomes from mCRC patients.ConclusionsThese differential proteins offer potential new candidate molecules for further research on the pathogenesis of mCRC and the identification of therapeutic targets. This study sheds light on the potential significance of plasma exosome proteomics studies in our understanding and treatment of mCRC.

Serum metabolomics analysis reveals potential biomarkers of penicillins-induced fatal anaphylactic shock in rats

Immunoglobulin E (IgE)-mediated immediate hypersensitivity reactions are the most concerning adverse events after penicillin antibiotics (PENs) administration because of their rapid progression and potential for fatal outcome. However, the diagnosis of allergic death is a forensic challenge because it mainly depends on nonspecific characteristic morphological changes, as well as exclusion and circumstantial evidence. In this study, an untargeted metabolomics approach based on liquid chromatography-mass spectrometry (LC-MS) was used to screen potential forensic biomarkers of fatal anaphylactic shock induced by four PENs (benzylpenicillin (BP), amoxicillin (AMX), oxacillin (OXA), and mezlocillin (MEZ)), and analyzed the metabolites, metabolic pathway and the mechanism which were closely related to the allergic reactions. The metabolomics results discovered that a total of 24 different metabolites in all four anaphylactic death (AD) groups, seven of which were common metabolites. A biomarker model consisting of six common metabolites (linoleic acid, prostaglandin D2, lysophosphatidylcholine (18:0), N-acetylhistamine, citric acid and indolelactic acid) AUC value of Receiver Operating Characteristic (ROC) curve was 0.978. Metabolism pathway analysis revealed that the pathogenesis of PENs-induced AD is closely related to linoleic acid metabolism. Our results revealed that the metabolomic profiling has potential in PENs-induced AD post-mortem diagnosis and metabolic mechanism investigations.

Comparative metabolomic analysis of spaghetti meat and wooden breast in broiler chickens: unveiling similarities and dissimilarities

IntroductionSpaghetti meat (SM) and wooden breast (WB) are emerging myopathies in the breast meat of fast-growing broiler chickens. The purpose of the study was to investigate the metabolomic differences between normal (N), SM, and WB fillets 24 h postmortem.Materials and methodsEight chicken breasts for each experimental group were collected from a commercial processing plant. Supernatant from tissue homogenates were subjected to ultra-performance liquid chromatographytandem mass spectrometry (UPLC-MS) analysis.Results and methodsA total of 3,090 metabolites were identified in the chicken breast meat. The comparison of WB and N showed 850 differential metabolites (P &amp;lt; 0.05), and the comparison of SM and N displayed 617 differential metabolites. The comparison of WB and SM showed 568 differential metabolites. The principal component analysis (PCA) plots showed a distinct separation between SM and N and between WB and N except for one sample, but SM and WB were not distinctly separated. Compared to N, 15-Hydroxyeicosatetraenoic acid (15-HETE) increased, and D-inositol-4-phosphate decreased in both SM and WB, indicating that cellular homeostasis and lipid metabolism can be affected in SM and WB. The abundance of nicotinamide adenine dinucleotide (NAD) + hydrogen (H) (NADH) was exclusively decreased between SM and N (P &amp;lt; 0.05). Purine metabolism was upregulated in SM and WB compared to N with a greater degree of upregulation in WB than SM. Folic acid levels decreased in SM and WB compared to N (P &amp;lt; 0.05). Steroid hormone biosynthesis was downregulated in SM compared to N (P &amp;lt; 0.05). Carbon metabolism was downregulated in SM and WB compared to N with greater degree of downregulation in WB than SM (P &amp;lt; 0.05). These data suggest both shared and unique metabolic alterations in SM and WB, indicating commonalities and differences in their underlying etiologies and meat quality traits. Dietary supplementation of deficient nutrients, such as NADH, folic acids, etc. and modulation of altered pathways in SM and WB would be strategies to reduce the incidence and severity of SM and WB.

Efficacité de 6 scénarios de décontamination de bras de fauteuils contaminés volontairement au cyclophosphamide

The arms of chairs in outpatient oncology clinics are frequently contaminated with cyclophosphamide. To evaluate the effectiveness of decontamination scenarios. This was a descriptive simulation-type study of 6 decontamination scenarios of a silicone fabric surface contaminated with 10 μg of cyclophosphamide. The decontamination products tested (quaternary ammonium, 0.5% hydrogen peroxide, 0.005% detergent, and sodium hypochlorite 0.5%) were applied with microfibre wipes. Residual contamination was measured using an ultra-performance liquid chromatography-tandem mass spectrometry system with identical cyclophosphamide detection and quantification limits (0.0006 ng/cm2). Among the 59 samples, 3 blanks were negative, 5 allowed measurement of the recovery rate (93.7% [standard deviation 4.6%]), and 51 were experimental. The average efficiency of the agents was greater than or equal to 99.79%. Regardless of the agent used, effectiveness was 99.30% (SD 1.20%) after 1 cleanse (n = 18), 99.90% (SD 0.15%) after 2 cleanses (n = 18), and 99.95% (SD 0.06%) after 3 cleanses (n = 15). The 6 decontamination scenarios were effective. Repeated cleaning marginally increased the effectiveness of decontamination.

Bio-functional properties of Jilungin (Terminalia canescens).

Jilungin (Terminalia canescens) is a native Australian plant and the Indigenous "Nyul Nyul" people of the Kimberleyregion of Western Australia use its leaves to make herbal tea. Due to the rise in the popularity of drinking Jilungin tea among the consumers in Australia and internationally, it is important to study the nutritional and health-beneficial properties as well as safety of Jilungin leaves. This study aims to determine the nutritional composition, anti-nutritional factors, antimicrobial and antidiabetic properties of Jilungin leaves. Also, the phytochemical profiling using UHPLC-MS/MS (Ultra-performance liquid chromatographymass spectrometry) and antioxidant activity of Jilungin methanolic extracts and herbal infusion were investigated. The safety of the leaves and infusion was also investigated by using in vitro mammalian cell lines (Caco2, HT29, and HepG2) through cell viability assays. The leaves are rich in dietary fiber (43.9%) and linoleic acid (30.4% of total fatty acids). Phytochemical profiling revealed ellagic acid, geraniin, pedunculagin, and punicalagin as the major bioactive compounds. The results also demonstrated that Jilungin has strong antioxidant and antidiabetic activities. A significant (p<0.01) strong positive correlation was observed between the high antioxidant activity of Jilungin infusion with the major bioactive compounds. Jilungin extracts (50mg/mL) exhibited strong antimicrobial activity against Staphylococcus aureus and Bacillus cereus. Its infusion and methanolic extract were safe on the studied cell lines (Caco-2, HT29, and HepG2) at higher concentrations of 66.6 and 98mg/mL, respectively. Therefore, Jilungin teas or infusions could be a safe and effective way to promote health and well-being. PRACTICAL APPLICATION: Jilungin tea is very popular among consumers in Australia and is gaining popularity worldwide. The current study will increase knowledge on the nutritional aspects and safety of the Jilungin use.

Quantifying allergenic proteins using antibody-based methods or liquid chromatography-mass spectrometry/mass spectrometry: A review about the influence of food matrix, extraction, and sample preparation.

Accurate quantification of allergens in food is crucial for ensuring consumer safety. Pretreatment steps directly affect accuracy and efficiency of allergen quantification. We systematically reviewed the latest advances in pretreatment steps for antibody-based methods and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) protein quantification methods in food. For antibody-based methods, the effects induced by food matrix like decreased allergen solubility, epitope masking, and nonspecific binding are of the upmost importance. To mitigate interference from the matrix, effective and proper extraction can be used to obtain the target allergens with a high protein concentration and necessary epitope exposure. Removal of interfering substances, extraction systems (buffers and additives), assistive technologies, and commercial kits were discussed. About LC-MS/MS quantification, the preparation of the target peptides is the crucial step that significantly affects the efficiency and results obtained from the MS detector. The advantages and limitations of each method for pre-purification, enzymatic digestion, and peptide desalting were compared. Additionally, the application characteristics of microfluidic-based pretreatment devices were illustrated to improve the convenience and efficiency of quantification. A promising research direction is the targeted development of pretreatment methods for complex food matrices, such as lipid-based and carbohydrate-based matrices.

Elevated Circulating Levels of Gut Microbe-Derived Trimethylamine N-Oxide Are Associated with Systemic Sclerosis

Background/Objectives: Alterations in fecal microbial communities in patients with systemic sclerosis (SSc) are common, but the clinical significance of this observation is poorly understood. Gut microbial production of trimethylamine (TMA), and its conversion by the host to trimethylamine N-oxide (TMAO), has clinical and mechanistic links to cardiovascular and renal diseases. Direct provision of TMAO has been shown to promote fibrosis and vascular injury, hallmarks of SSc. We sought to determine levels of TMAO and related metabolites in SSc patients and investigate associations between the metabolite levels with disease features. Methods: This is an observational case:control study. Adults with SSc (n = 200) and non-SSc controls (n = 400) were matched for age, sex, indices of renal function, diabetes mellitus, and cardiovascular disease. Serum TMAO, choline, betaine, carnitine, γ-butyrobetaine, and crotonobetaine were measured using stable isotope dilution liquid chromatography tandem mass spectrometry. Results: Median TMAO concentration was higher (p = 0.020) in SSc patients (3.31 [interquartile range 2.18, 5.23] µM) relative to controls (2.85 [IQR 1.88, 4.54] µM). TMAO was highest among obese and male SSc participants compared to all other groups. Following adjustment for sex, BMI, age, race, and eGFR in a quantile regression model, elevated TMAO levels remained associated with SSc at each quantile of TMAO. Conclusions: Patients with SSc have increased circulating levels of TMAO independent of comorbidities including age, sex, renal function, diabetes mellitus, and cardiovascular disease. As a potentially modifiable factor, further studies examining the link between TMAO and SSc disease severity and course are warranted.

The vaginal metabolomics profile with features of polycystic ovary syndrome: a pilot investigation in China

Background Polycystic ovary syndrome (PCOS) is the most common metabolic disorder and reproductive endocrine disease, posing an elevated risk to women of reproductive age. Although metabolism differences in serum, amniotic fluid and urine have been documented in PCOS, there remains a paucity of evidence for vaginal fluid. This study aimed to identify the metabolic characteristics and potential biomarkers of PCOS in Chinese women of reproductive age. Methods We involved ten newly diagnosed PCOS women who attended gynecology at Zhongda Hospital and matched them with ten healthy controls who conducted health check-up programs at Gulou Maternal and Child Health Center in Nanjing, China from January 1st, 2019 to July 31st, 2020. Non-targeted metabolomics based on ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was applied to differentially screen vaginal metabolites between PCOS group and healthy controls. Principal component analysis (PCA), orthogonal partial least-squares discriminant analysis (OPLS-DA) and enrichment analysis were used to observe differences, search for potential biomarkers and enrich related pathways. Results Among the 20 participants, a total of 195 different metabolites were detected between PCOS group and healthy control group. PCOS and control groups were effectively separated by vaginal fluid. Lipids and lipid-like molecules constituted the majority of differential metabolites. Notably, dopamine exhibited an increased trend in PCOS group and emerged as the most significant differential metabolite, suggesting its potential as a biomarker for identifying PCOS. The application of UHPLC-MS/MS based vaginal metabolomics methods showed significant differences between PCOS and non-PCOS healthy control groups, especially linoleic acid metabolism disorder. Most differential metabolites were enriched in pathways associated with linoleic acid metabolism, phenylalanine metabolism, tyrosine metabolism, nicotinate and nicotinamide metabolism or arachidonic acid metabolism. Conclusions In this pilot investigation, significant metabolomics differences could be obtained between PCOS and healthy control groups. For PCOS women of reproductive age, vaginal metabolism is a more economical, convenient and harmless alternative to provide careful personalized health diagnosis and potential targets for therapeutic intervention.

Widely Targeted Metabolomics Analysis of the Roots, Stems, Leaves, Flowers, and Fruits of Camellia luteoflora, a Species with an Extremely Small Population

Camellia luteoflora is a rare and endangered plant endemic to China. It has high ornamental and potential economic and medicinal value, and is an important germplasm resource of Camellia. To understand the distributions and differences in metabolites from different parts of C. luteoflora, in this study, we used liquid chromatography–tandem mass spectrometry (LC–MS/MS) to examine the types and contents of chemical constituents in five organs of C. luteoflora: roots, stems, leaves, flowers, and fruits. The results showed that a total of 815 metabolites were identified in the five organs and were classified into 18 main categories, including terpenoids (17.1%), amino acids (10.4%), flavonoids (10.3%), sugars and alcohols (9.8%), organic acids (9.0%), lipids (7.1%), polyphenols (4.8%), alkaloids (4.8%), etc. A total of 684 differentially expressed metabolites (DEMs) in five organs were obtained and annotated into 217 KEGG metabolic pathways, among which metabolic pathways, ABC transporters, the biosynthesis of cofactors, and the biosynthesis of amino acids were significantly enriched. In DEMs, flowers are rich in flavonoids, polyphenols, organic acids, and steroids; fruits are rich in amino acids, alkaloids, vitamins, and xanthones; stems are rich in lignans; and leaves have the highest relative content of phenylpropanoids, ketoaldehydic acids, quinones, sugars and alcohols, terpenoids, coumarins, lipids, and others; meanwhile, the metabolite content is lower in roots. Among the dominant DEMs, 58 were in roots, including arachidonic acid, lucidone, isoliquiritigenin, etc.; 75 were in flowers, including mannose, shikimic acid, d-gluconic acid, kaempferol, etc.; 45 were in the fruit, including pterostilbene, l-ascorbic acid, riboflavin, etc.; 27 were in the stems, including salicylic acid, d-(-)-quinic acid, mannitol, (-)-catechin gallate, etc.; there was a maximum number of 119 dominant metabolites in the leaves, including oleanolic acid, l-glucose, d-arabitol, eugenol, etc. In sum, the rich chemical composition of C. luteoflora and the significant differences in the relative contents of metabolites in different organs will provide theoretical references for the study of tea, flower tea, edible oil, nutraceuticals, and the medicinal components of C. luteoflora.

A single-dose, randomized, crossover bioequivalence study of levamlodipine besilate tablets in healthy subjects.

Levamlodipine, the levorotatory form of amlodipine racemate, has a blood pressure-lowering effect that is twice that of the racemate. The study aims to establish a foundation for the clinical application of the test drug by conducting a phase I clinical bioequivalence trial, comparing its bioequivalence and safety with the reference drug in healthy Chinese subjects. Recruiting 26 healthy subjects for separate bioequivalence trials in both fasting and fed conditions. The subjects will orally administer 2.5-mg test drug and 5-mg reference drug. A chiral method was used for bioanalytics and liquid chromatography-tandem mass spectrometry was employed to quantify the (S)-amlodipine concentrations at various time points after administration. In fasting condition, the geometric mean ratios (GMRs) for the primary pharmacokinetic parameters Cmax, AUC0-t, and AUC0-∞ are 100.24%, 103.63%, and 103.24%, respectively. The 90% confidence intervals (CIs) fall within the range of 80-125%, satisfying the established bioequivalence criteria. Similarly, upon oral administration of the drugs in the fed condition, the GMRs for Cmax, AUC0-t, and AUC0-∞ are 96.48%, 99.90%, and 99.62%, respectively. The corresponding 90% CIs are within the limits of 80-125%, meeting the predefined bioequivalence standards. Furthermore, both drugs exhibited favorable safety profiles. The results show that the two drugs are bioequivalent in healthy Chinese subjects under both fasting and fed conditions. The two drugs both had similar PK parameters and good safety.