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The molecular mechanisms by which worm parasites evade host immunity are incompletely understood. In a mouse model of intestinal helminth infection using Heligmosomoides polygyrus bakeri ( Hpb ), we show that helminthic glutamate dehydrogenase (heGDH) drives parasite chronicity by suppressing macrophage-mediated host defense. Combining RNA-seq, ChIP-seq, and targeted lipidomics, we identify prostaglandin E 2 (PGE 2 ) as a major immune regulatory mechanism of heGDH. The induction of PGE 2 and other immunoregulatory factors, including IL-12 family cytokines and indoleamine 2,3-dioxygenase 1, by heGDH required p300-mediated histone acetylation, whereas the enzyme's catalytic activity suppressed the synthesis of type 2-promoting leukotrienes by macrophages via 2-hydroxyglutarate. By contrast, the induction of immunoregulatory factors involved the heGDH N terminus by potentially mediating interactions with cellular targets (CD64 and GPNMB) identified by proteomics. Type 2 cytokines counteracted suppressive effects of heGDH on host defense, indicating that type 2 immunity can limit helminth-driven immune evasion. Thus, helminths harness a ubiquitous metabolic enzyme to epigenetically target type 2 macrophage activation and establish chronicity.

Rationale: Growing evidence suggests that air pollution exposure is a major risk factor in chronic obstructive pulmonary disease (COPD) that is associated with an increased prothrombotic state and adverse cardiovascular outcomes. However, much of this work is based on observational data or human exposure studies involving younger participants. The biological causality and mechanism of air pollution-induced prothrombotic response in patients with COPD remain to be explored. Objectives: The main aim of this work was to investigate the impact of short-term diesel exhaust (DE) exposure on circulating prothrombotic markers-fibrinogen and plasminogen activator inhibitor-1 (PAI-1)-and urinary eicosanoids in patients with COPD. Methods: Twenty-nine research participants were recruited in this randomized, double-blind, crossover, controlled human exposure study to DE. Participants included former smokers with and without mild or moderate COPD (ex-smokers [ES] and COPD group) and healthy never-smokers without COPD (nonsmoker [NS] group). Each participant was exposed to DE (300 μg/m 3 of particulate matter with an aerodynamic diameter ≤2.5 μm) and filtered air for 2 hours on different occasions, in randomized order, separated by a 4-week washout. Blood and urine samples were collected before and 24 hours after each exposure. Plasma fibrinogen and serum PAI-1 concentrations were quantified using enzyme-linked immunosorbent assays. Urinary eicosanoid concentrations were quantified using ultraperformance liquid chromatography coupled to tandem mass spectrometry. Linear mixed-effects models were used for statistical comparisons. Results: Participants with COPD showed an increase in plasma fibrinogen (effect estimate, 1.27 [1.06-1.53]; P  = 0.01) after DE relative to filtered air, but no significant DE-associated change in serum PAI-1 (0.95 [0.87-1.04]; P  = 0.26). In never-smokers and ex-smokers without COPD, fibrinogen (NS group, 1.10 [0.99-1.23]; P  = 0.08; ES group, 0.86 [0.68-1.09]; P  = 0.08] and PAI-1 (NS group, 1.12 [0.96-1.32]; P  = 0.15; ES group, 0.90 [0.79-1.03]; P  = 0.13) were not changed after DE exposure. Participants with COPD showed a DE-attributable increase in urinary thromboxane B2 (TXB 2 ) metabolite concentrations as follows: 11-dehydro-TXB 2 (1.45 [1.02-2.08]; P  = 0.04) and 2,3-dinor-TXB 2 (1.45 [1.05-2.00]; P  = 0.03). Conclusions: Participants with COPD had increased plasma fibrinogen and urinary TXB 2 metabolites after short-term DE exposure, suggesting they may be more susceptible to a pollution-attributable prothrombotic response than healthy control subjects or ex-smokers without COPD. Clinical trial registered with www.clinicaltrials.gov (NCT02236039).

Background: Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are important causes of morbidity and mortality in critically ill patients. Gastric contents aspiration is one of the most common causes of ALI/ARDS. To date, there are still no specific and effective pharmacological treatments for ALI/ARDS. Polyvinylalcohol-carbazate (PVAC), a polymer that can bind endogenous aldehydes, neutralize oxidative stress and inhibit inflammatory factors, may be a potential treatment for ALI/ARDS., Methods: A hydrochloric acid (HCl) induced mouse model was employed to assess the effect of PVAC. The changes of lung mechanics, pulmonary edema, histology and immune cells, cytokines, and lipid mediators in bronchioalveolar lavage fluid (BALF) were investigated in HCl-challenged mice., Results: In the HCl model, PVAC administration alleviated airway hyperresponsiveness and improved pulmonary edema and damage. In addition, it decreased the recruitment of neutrophils to the lung, and inhibited the increase of IL-6, TNF-α and leukotriene B 4 ., Conclusion: These data indicates that PVAC is a potential candidate for the treatment of ALI/ARDS induced by aspiration of gastric acid or for the control of "asthma-like" symptoms in patients with gastroesophageal reflux., Competing Interests: A patent using PVAC as an anti-inflammatory drug has been granted (Active principle for mitigating undesired medical conditions, WO 2012/105887 A1). The patent is owned by PVAC Medical Technologies Ltd (PMT). TE and TB are shareholders of PMT and have acted as consultants towards the company developing PVAC for clinical applications. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Dong, Liu, Quaranta, Jing, Nie, Wheelock, Murrell, Coquet, Bowden, Engstrand and Adner.)

Background: Limited studies have investigated the influence of body mass index (BMI) trajectories on lung function covering the entire growth period., Methods: We conducted a prospective study utilizing data from the Swedish BAMSE birth cohort. Latent class mixture modelling was employed to examine the diversity in BMI z-scores from birth to 24 years of age. Participants with four or more BMI z-scores were included (n=3204, 78·4%). Pre-bronchodilator (BD) spirometry was tested at 8, 16, and 24 years, while post-BD spirometry, multiple-breath nitrogen washout (for lung clearance index, LCI), and urinary metabolomics data were assessed at 24 years., Results: Six distinct BMI development groups were identified. Compared to the stable normal BMI group, the accelerated increasing BMI group exhibited reduced pre- and post-BD FEV 1 /FVC ratio z scores (β=-0·26, 95% CI=[-0·44, -0·08], and -0·22, [ -0·39, -0·05], respectively), along with elevated LCI (0·30, [0·22, 0·42]) at 24 years. The persistent high BMI group demonstrated lower FEV 1 , and FVC z scores growth between 16 and 24 years (-0.24, [-0.42, -0.05], and -0.27, [-0.45, -0.01], respectively), and elevated LCI (0·20, [0·03, 0·39]) at 24 years. However, those impairments were not observed in the accelerated resolving BMI group. Conversely, the persistent low BMI group displayed persistently decreased FEV 1 , and FVC from 8 to 24 years, as well as decreased lung function growth. Additionally, histidine-related metabolites were associated with pre- and post-BD FEV 1 (hypergeometric FDR=0.008 and <0.001, respectively)., Conclusions: Early interventions aiming for normal BMI during childhood may contribute to improved lung health later in life., (Copyright ©The authors 2024.)

Background: Lung quantitative computed tomography (qCT) severe asthma clusters have been reported, but their replication and underlying disease mechanisms are unknown. We identified and replicated qCT clusters of severe asthma in two independent asthma cohorts and determined their association with molecular pathways, using radiomultiomics, integrating qCT, multiomics and machine learning/artificial intelligence., Methods: We used consensus clustering on qCT measurements of airway and lung CT scans, performed in 105 severe asthmatic adults from the U-BIOPRED cohort. The same qCT measurements were used to replicate qCT clusters in a subsample of the ATLANTIS asthma cohort (n=97). We performed integrated enrichment analysis using blood, sputum, bronchial biopsies, bronchial brushings and nasal brushings transcriptomics and blood and sputum proteomics to characterise radiomultiomic-associated clusters (RACs)., Results: qCT clusters and clinical features in U-BIOPRED were replicated in the matched ATLANTIS cohort. In the U-BIOPRED cohort, RAC1 (n=30) was predominantly female with elevated body mass index, mild airflow limitation, decreased CT lung volume and increased lung density and upregulation of the complement pathway. RAC2 (n=34) subjects had airway wall thickness and a mild degree of airflow limitation, with upregulation of proliferative pathways including neurotrophic receptor tyrosine kinase 2/tyrosine kinase receptor B, and downregulation of semaphorin pathways. RAC3 (n=41) showed increased lung attenuation area and air trapping, severe airflow limitation, hyperinflation, and upregulation of cytokine signalling and signalling by interleukin pathways, and matrix metallopeptidase 1, 2 and 9., Conclusions: U-BIOPRED severe asthma qCT clusters were replicated in a matched independent asthmatic cohort and associated with specific molecular pathways. Radiomultiomics might represent a novel strategy to identify new molecular pathways in asthma pathobiology., Competing Interests: Conflict of interest: K.F. Chung reports grants from the MRC, EPSRC, GSK, Merck and NIEHS, payment or honoraria for lectures, presentations, manuscript writing or educational events from GSK, Novartis and AstraZeneca, and participation on a data safety monitoring board or advisory board with GSK, AstraZeneca, Novartis, Roche, Merck, Trevi, Rickett-Beckinson, Nocion, Shionogi and Clean Breathing Institute supported by Haleon. C. Auffray reports support for the present study from the Innovative Medicines Initiative. Y. Badi reports support for the present study from the Innovative Medicines Initiative. P. Bakke reports payment or honoraria for lectures, presentations, manuscript writing or educational events from AstraZeneca, GSK and Sanofi. C. Brightling reports support for the present study from the ATLANTIS study (Chiesi grant) and Leicester NIHR BRC, grants from 4D Pharma, Areteia, AstraZeneca, Chiesi, Genentech, GSK, Mologic, Novartis, Regeneron Pharmaceuticals, Roche and Sanofi, and consultancy fees from 4D Pharma, Areteia, AstraZeneca, Chiesi, Genentech, GSK, Mologic, Novartis, Regeneron Pharmaceuticals, Roche and Sanofi. P. Chanez reports grants from ALK, AstraZeneca, Boehringer Ingelheim, Chiesi, GSK, Menarini, Novartis and Sanofi Aventis, consultancy fees from ALK, AstraZeneca, Boehringer Ingelheim, Chiesi, GSK, Menarini, Novartis and Sanofi Aventis, payment or honoraria for lectures, presentations, manuscript writing or educational events from ALK, AstraZeneca, Boehringer Ingelheim, Chiesi, GSK, Menarini, Novartis and Sanofi Aventis, and support for attending meetings from ALK, AstraZeneca, Boehringer Ingelheim, Chiesi, GSK, Menarini, Novartis and Sanofi Aventis. B. De Meulder reports support for the present study from the Innovative Medicines Initiative. R. Djukanovic reports consultancy fees from Synairgen plc, GSK, ZenasBio and Celltrion, leadership role as Chair of the European Respiratory Society's clinical research collaboration on severe asthma (SHARP), and stock (or stock options) with Synairgen plc. L. Fabbri reports consultancy fees from Chiesi Farmaceutici and AstraZeneca, payment or honoraria for lectures, presentations, manuscript writing or educational events from Chiesi Farmaceutici, AstraZeneca, GSK, Alfasigma and Novartis, support for attending meetings from Chiesi Farmaceutici, GSK and Novartis, and participation on a data safety monitoring board or advisory board with Novartis and Chiesi. S.J. Fowler reports grants from the NIHR, and payment or honoraria for lectures, presentations, manuscript writing or educational events from Boehringer Ingelheim. P. Howarth reports employment with GSK. J. Kolmert reports consultancy fees from Gesynta Pharma AB and Lipum AB. M. Kraft reports grants from the NIH, American Lung Association, Synairgen, Janssen, AstraZeneca and Sanofi, consultancy fees from AstraZeneca, Sanofi, Chiesi, GSK, Kinaset and Genentech, payment or honoraria for lectures, presentations, manuscript writing or educational events from Chiesi, support for attending meetings from the European Respiratory Society, one patent issued and tiled filed to development of therapeutics for inflammatory lung disease as CoFounder and Chief Medical Officer, RaeSedo, Inc., participation on a data safety monitoring board or advisory board with ALung, leadership role with the National Heart, Lung and Blood Advisory Council, stock (or stock options) with RaeSedo, Inc. (equity ownership), and the following financial (or non-financial) interests: Section Editor of UpToDate. A.H. Maitland-van der Zee reports grants from Health Holland, GSK, Boehringer Ingelheim and Vertex, consultancy fees from Boehringer Ingelheim and AstraZeneca, payment or honoraria for lectures, presentations, manuscript writing or educational events from GSK, and participation on a data safety monitoring board or advisory board for a study on BPD in neonates. A. Papi reports grants from Chiesi, AstraZeneca, GSK and Sanofi, consultancy fees from Chiesi, AstraZeneca, GSK, Novartis, Sanofi, Iqvia, Avillion, Elpen Pharmaceuticals, Moderna and Roche, payment or honoraria for lectures, presentations, manuscript writing or educational events from Chiesi, AstraZeneca, GSK, Menarini, Zambon, Mundipharma, Sanofi, Edmond Pharma, Iqvia, Avillion, Sanofi and Regeneron, participation on a data safety monitoring board or advisory board with Chiesi, AstraZeneca, GSK, Novartis, Sanofi, Iqvia, Avillion, Elpen Pharmaceuticals and Moderna, receipt of equipment, materials, drugs, medical writing, gifts or other services from Consorzio Futuro in Ricerca. K. Rabe reports payment or honoraria for lectures, presentations, manuscript writing or educational events from AstraZeneca, Boehringer Ingelheim, Chiesi Pharmaceuticals, Novartis, Sanofi/Regeneron, GSK, Berlin Chemie and Roche Pharma, participation on a data safety monitoring board or advisory board with AstraZeneca, Boehringer Ingelheim, Sanofi/Regeneron and CSL Behring, and leadership roles with the German Center for Lung Research (DZL), German Chest Society (DGP) and American Thoracic Society. D.E. Shaw reports consultancy fees from GSK, AstraZeneca and Novartis, payment or honoraria for lectures, presentations, manuscript writing or educational events from GSK and AstraZeneca, and support for attending meetings from GSK. D. Singh reports consultancy fees from Aerogen, AstraZeneca, Boehringer Ingelheim, Chiesi, Cipla, CSL Behring, EpiEndo, Genentech, GSK, Glenmark, Gossamer Bio, Kinaset Therapeutics, Menarini, Novartis, Orion, Pulmatrix, Sanofi, Synairgen, Teva, Theravance, Biopharma and Verona Pharma. M. van Den Berge reports grants from GSK, Roche, Genentech and Novartis. Y. Guo reports support for the present study from the Innovative Medicines Initiative. S. Wagers reports consultancy fees from King's College Hospital NHS Foundation Trust, Academic Medical Research, AMC Medical Research BV, Asthma UK, Athens Medical School, Boehringer Ingelheim International GmbH, CHU de Toulouse, CIRO, DS Biologicals Ltd, École Polytechnique Fédérale De Lausanne, European Respiratory Society, FISEVI, Fluidic Analytics Ltd, Fraunhofer IGB, Fraunhofer ITEM, GSK Research & Development Ltd, Holland & Knight, Karolinska Institutet Fakturor, KU Leuven, Longfonds, National Heart and Lung Institute, Novartis Pharma AG, Owlstone Medical Limited, PExA AB, UCB Biopharma SPRL, Umeå University, University Hospital Southampton NHS Foundation Trust, Università Campus Bio-Medico di Roma, Universita Cattolica Del Sacro Cuore, Universität Ulm, University of Bern, University of Edinburgh, University of Hull, University of Leicester, University of Loughborough, University of Luxembourg, University of Manchester, University of Nottingham, Vlaams Brabant, Dienst Europa, Imperial College London, Boehringer Ingelheim, Breathomix, Gossamer Bio, AstraZeneca, CIBER, OncoRadiomics, University of Leiden, University of Wurzburg, Chiesi Pharmaceutical, University of Liege, Teva Pharmaceuticals, Sanofi, Pulmonary Fibrosis Foundation and Three Lakes Foundation. P.J. Sterk reports consultancy fees from SME Breathomix, and stock (or stock options) with SME Breathomix. S-E. Dahlen reports grants from AstraZeneca, GSK and Sanofi, consultancy fees from AstraZeneca, Cayman Chemicals, GSK and Regeneron, and payment or honoraria for lectures, presentations, manuscript writing or educational events from AstraZeneca, GSK and Sanofi. I.M. Adcock reports support for the present study from the Innovative Medicines Initiative, grants from GSK, MRC, EPSRC and Sanofi, consultancy fees from GSK, Sanofi, Chiesi and Kinaset, payment or honoraria for lectures, presentations, manuscript writing or educational events from AstraZeneca, Sanofi, Eurodrug and Sunovion, and support for attending meetings from AstraZeneca. S. Siddiqui consultancy fees from AstraZeneca, GSK, CSL Behring, Areteia Therapeutics, ERT Medical, Chiesi and Roche, and payment or honoraria for lectures, presentations, manuscript writing or educational events from GSK, Chiesi and AstraZeneca. P. Montuschi reports support for the present study from the Innovative Medicines Initiative. The remaining authors have no potential conflicts of interest to disclose., (Copyright ©The authors 2024.)

Oxylipins are a class of low-abundance lipids formed via oxygenation of fatty acids. These compounds include potent signaling molecules (e.g., octadecanoids, eicosanoids) that can exert essential functions in the pathophysiology of inflammatory diseases including asthma. While some oxylipin signaling cascades have been unraveled using LC-MS/MS-based methods, measurements in homogenate samples do not represent the spatial heterogeneity of lipid metabolism. Mass spectrometry imaging (MSI) directly detects analytes from a surface, which enables spatial mapping of oxylipin biosynthesis and migration within the tissue. MSI has lacked the sensitivity to routinely detect low-abundance oxylipins; however, new multiple-reaction-monitoring (MRM)-based MSI technologies show increased sensitivity. In this study, we developed a workflow to apply desorption electrospray ionization coupled to a triple quadrupole mass spectrometer (DESI-MRM) to spatially map oxylipins in pulmonary tissue. The targeted MSI workflow screened guinea pig lung extracts using LC-MS/MS to filter oxylipin targets based on their detectability by DESI-MRM. A panel of 5 oxylipins was then selected for DESI-MRM imaging derived from arachidonic acid (TXB 2 , 11-HETE, 12-HETE), linoleic acid (12,13-DiHOME), and α-linolenic acid (16-HOTrE). To parse this new data type, a custom-built R package (quantMSImageR) was developed with functionality to label regions of interest as well as quantify and analyze lipid distributions. The spatial distributions quantified by DESI-MRM were supported by LC-MS/MS analysis, with both indicating that 16-HOTrE and 12-HETE were associated with airways, while 12,13-DiHOME and arachidonic acid were mapped to parenchyma. This study realizes the potential of targeted MSI to routinely map low-abundance oxylipins with high specificity at scale.

Background: The immunometabolic mechanisms underlying variable responses to oral immunotherapy (OIT) in patients with IgE-mediated food allergy are unknown., Objective: To identify novel pathways associated with tolerance in food allergy, we used metabolomic profiling to find pathways important for food allergy in multiethnic cohorts and responses to OIT., Methods: Untargeted plasma metabolomics data were generated from the VDAART healthy infant cohort (N = 384), a Costa Rican cohort of children with asthma (N = 1040), and a peanut OIT trial (N = 20) evaluating sustained unresponsiveness (SU, protection that lasts after therapy) versus transient desensitization (TD, protection that ends immediately afterward). Generalized linear regression modeling and pathway enrichment analysis identified metabolites associated with food allergy and OIT outcomes., Results: Compared with unaffected children, those with food allergy were more likely to have metabolomic profiles with altered histidines and increased bile acids. Eicosanoids (e.g., arachidonic acid derivatives) (q = 2.4 × 10 -20 ) and linoleic acid derivatives (q = 3.8 × 10 -5 ) pathways decreased over time on OIT. Comparing SU versus TD revealed differing concentrations of bile acids (q = 4.1 × 10 -8 ), eicosanoids (q = 7.9 × 10 -7 ), and histidine pathways (q = .015). In particular, the bile acid lithocholate (4.97 [1.93, 16.14], p = .0027), the eicosanoid leukotriene B4 (3.21 [1.38, 8.38], p = .01), and the histidine metabolite urocanic acid (22.13 [3.98, 194.67], p = .0015) were higher in SU., Conclusions: We observed distinct profiles of bile acids, histidines, and eicosanoids that vary among patients with food allergy, over time on OIT and between SU and TD. Participants with SU had higher levels of metabolites such as lithocholate and urocanic acid, which have immunomodulatory roles in key T-cell subsets, suggesting potential mechanisms of tolerance in immunotherapy., (© 2024 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Background: The ketogenic diet (KD) is a high fat, sufficient protein, and low carbohydrate dietary therapy for drug-resistant epilepsy. The underlying mechanisms of action of the KD remain unclear. In mice, the microbiota is necessary for the anti-seizure effect and specific microbes influence circulatory levels of metabolites that are linked to seizure reduction. However, it remains unclear which changes are linked to seizure reduction in patients with epilepsy., Methods: We analysed the serum metabolome of children with drug-resistant epilepsy (n = 14) before and after three months on KD. Metabolomic changes were correlated to the gut microbiome and treatment outcome, i.e., seizure reduction., Findings: In this prospective observational study, we uncovered associations between microbial species and serum metabolites that correlated with seizure reduction. Plasmalogens were most strongly linked to seizure reduction and had significant positive correlations with several gut microbes (e.g., Faecalibacterium prausnitzii, Alistipes communis, Alistipes shahii, and Christensenella minuta) while significant negative correlations were found for five strains of Escherichia coli. Infant-type Bifidobacteria correlated negatively with other metabolites associated with seizure reduction., Interpretation: The microbes and metabolites identified here may contribute to the therapeutic effect of the KD in children with drug-resistant epilepsy. Several of these metabolites (e.g., plasmalogens) play important roles in neurobiology and may influence seizures. Based on our findings, anti-seizure therapeutic strategies could be developed involving the targeted manipulation of the gut microbiota and/or its metabolites., Funding: This study was supported by the Swedish Brain Foundation, Margarethahemmet Society, Sunnerdahls Handikappfond, Stockholm County Council Research Funds, and Linnea & Josef Carlssons Foundation., Competing Interests: Declaration of interests None of the authors has any conflict of interest to disclose. We confirm that we have read the Journal's position on issues involved in ethical publication and affirm that this report is consistent with those guidelines., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Pharmaceutical compounds have become one of the main contaminants of emerging concern (CECs) due to their high usage and increased release into the environment. This study aims to assess the effects caused by three widely consumed hepatotoxic pharmaceutical compounds: an antibiotic (amoxicillin), an antiepileptic (carbamazepine), and an antidepressant (trazodone), on human health when indirectly exposed to toxicologically relevant concentrations (30, 15, and 7.5 μM for amoxicillin and carbamazepine, and 4, 2, and 1 μM for trazodone). A combination of semi-targeted metabolomic and targeted sphingolipid analyses was chosen to unravel the metabolic alterations in human hepatic cells exposed to these CECs at three concentrations for 24 h. HepG2 hepatoma cells were encapsulated in sodium alginate spheroids to improve the physiological relevance of this in vitro approach. Statistical analysis was used to identify the most affected metabolites and sphingolipids for each drug exposure. The results revealed small but significant changes in response to carbamazepine and trazodone exposures, affecting sphingolipid, glycerophospholipid precursors, and amino acid metabolism. Under both drug treatments, a decrease in various ceramide species (related to cell signaling) was observed, along with reduced taurine levels (related to the biosynthesis of bile acid conjugates) and carnitine levels (suggesting an impact on energy production). These and other drug-specific changes indicate that cellular functions in liver cells might be altered under low doses of these CECs, potentially affecting the health of other organs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

In this community effort, we compare measurements between 34 laboratories from 19 countries, utilizing mixtures of labelled authentic synthetic standards, to quantify by mass spectrometry four clinically used ceramide species in the NIST (National Institute of Standards and Technology) human blood plasma Standard Reference Material (SRM) 1950, as well as a set of candidate plasma reference materials (RM 8231). Participants either utilized a provided validated method and/or their method of choice. Mean concentration values, and intra- and inter-laboratory coefficients of variation (CV) were calculated using single-point and multi-point calibrations, respectively. These results are the most precise (intra-laboratory CVs ≤ 4.2%) and concordant (inter-laboratory CVs < 14%) community-derived absolute concentration values reported to date for four clinically used ceramides in the commonly analyzed SRM 1950. We demonstrate that calibration using authentic labelled standards dramatically reduces data variability. Furthermore, we show how the use of shared RM can correct systematic quantitative biases and help in harmonizing lipidomics. Collectively, the results from the present study provide a significant knowledge base for translation of lipidomic technologies to future clinical applications that might require the determination of reference intervals (RIs) in various human populations or might need to estimate reference change values (RCV), when analytical variability is a key factor for recall during multiple testing of individuals., (© 2024. The Author(s).)

Importance: Eicosanoids have a pathophysiological role in atopic dermatitis (AD), but it is unknown whether this is affected by prenatal ω-3 long-chain polyunsaturated fatty acid (n-3 LCPUFA; ie, fish oil) supplementation and genetic variations in the cyclooxygenase-1 (COX1) pathway., Objective: To explore the association of n-3 LCPUFA supplementation during pregnancy with risk of childhood AD overall and by maternal COX1 genotype., Design, Setting, and Participants: This prespecified secondary analysis of a randomized clinical trial included mother-child pairs from the Danish Copenhagen Prospective Studies on Asthma in Childhood 2010 birth cohort, with prospective follow-up until children were aged 10 years. In the trial, maternal and child COX1 genotypes were determined, and urinary eicosanoids were quantified when the child was 1 year of age. The present study was conducted from January 2019 to December 2021, and data were analyzed from January to September 2023., Intervention: A total of 736 pregnant women at 24 weeks' gestation were randomized 1:1 to 2.4 g of n-3 LCPUFA (fish oil) or placebo (olive oil) per day until 1 week post partum., Main Outcomes and Measures: Risk of childhood AD until age 10 years overall and by maternal COX1 genotype., Results: At age 10 years, 635 children (91%; 363 [57%] female) completed the clinical follow-up, and these mother-child pairs were included in this study; 321 (51%) were in the intervention group and 314 (49%) in the control group. Pregnancy n-3 LCPUFA supplementation was associated with lower urinary thromboxane A2 metabolites at age 1 year (β, -0.46; 95% CI, -0.80 to -0.13; P = .006), which was also associated with COX1 rs1330344 genotype (β per C allele, 0.47; 95% CI, 0.20-0.73; P = .001). Although neither n-3 LCPUFA supplementation (hazard ratio [HR], 1.00; 95% CI, 0.76-1.33; P = .97) nor maternal COX1 genotype (HR, 0.94; 95% CI, 0.74-1.19; P = .60) was associated with risk of childhood AD until age 10 years, there was evidence of an interaction between these variables (P < .001 for interaction). Among mothers with the TT genotype, risk of AD was reduced in the n-3 LCPUFA group compared with the placebo group (390 mother-child pairs [61%]; HR, 0.70; 95% CI, 0.50-0.98; P = .04); there was no association for mothers with the CT genotype (209 [33%]; HR, 1.29; 95% CI, 0.79-2.10; P = .31), and risk was increased among offspring of mothers with the CC genotype (37 [6%]; HR, 5.77; 95% CI, 1.63-20.47; P = .007). There was a significant interaction between n-3 LCPUFA supplementation and child COX1 genotype and development of AD (P = .002 for interaction)., Conclusions and Relevance: In this secondary analysis of a randomized clinical trial, the association of prenatal n-3 LCPUFA supplementation with risk of childhood AD varied by maternal COX1 genotype. The findings could be used to inform a personalized prevention strategy of providing supplementation only to pregnant individuals with the TT genotype., Trial Registration: ClinicalTrials.gov: NCT00798226.

In recent years, instrumental improvements have enabled the spread of mass spectrometry-based lipidomics platforms in biomedical research. In mass spectrometry, the reliability of generated data varies for each compound, contingent on, among other factors, the availability of labeled internal standards. It is challenging to evaluate the data for lipids without specific labeled internal standards, especially when dozens to hundreds of lipids are measured simultaneously. Thus, evaluation of the performance of these platforms at the individual lipid level in interlaboratory studies is generally not feasible in a time-effective manner. Herein, using a focused subset of sphingolipids, we present an in-house validation methodology for individual lipid reliability assessment, tailored to the statistical analysis to be applied. Moreover, this approach enables the evaluation of various methodological aspects, including discerning coelutions sharing identical selected reaction monitoring transitions, pinpointing optimal labeled internal standards and their concentrations, and evaluating different extraction techniques. While the full validation according to analytical guidelines for all lipids included in a lipidomics method is currently not possible, this process shows areas to focus on for subsequent method development iterations as well as the robustness of data generated across diverse methodologies., (© 2024. The Author(s).)

Background: Eicosanoids are lipid mediators including thromboxanes (TXs), prostaglandins (PGs), and leukotrienes with a pathophysiological role in established atopic disease. However, their role in the inception of disease is unclear. This study aimed to investigate the association between urinary eicosanoids in early life and development of atopic disease., Methods: This study quantified the levels of 21 eicosanoids in urine from children from the COPSAC 2010 (Copenhagen Prospective Studies on Asthma in Childhood 2010) (age 1 year, n = 450) and VDAART (Vitamin D Antenatal Asthma Reduction Trial) (age 3 years, n = 575) mother-child cohorts and analyzed the associations with development of wheeze/asthma, atopic dermatitis, and biomarkers of type-2 inflammation, applying false discovery rate of 5% (FDR5%) multiple testing correction., Results: In both cohorts, analyses adjusted for environmental determinants showed that higher TXA 2 eicosanoids in early life were associated with increased risk of developing atopic dermatitis (P < FDR5%) and type-2 inflammation (P < .05). In VDAART, lower PGE 2 and PGI 2 eicosanoids and higher isoprostanes were also associated with increased risk of atopic dermatitis (P < FDR5%). For wheeze/asthma, analyses in COPSAC 2010 showed that lower isoprostanes and PGF 2 eicosanoids and higher PGD 2 eicosanoids at age 1 year associated with an increased risk at age 1-10 years (P < .05), whereas analyses in VDAART showed that lower PGE 2 and higher TXA 2 eicosanoids at age 3 years associated with an increased risk at 6 years (P < FDR5%)., Conclusions: This study suggests that early life perturbations in the eicosanoid metabolism are present before the onset of atopic disease in childhood, which provides pathophysiological insight in the inception of atopic diseases., Competing Interests: Disclosure Statement COPSAC is funded by private and public research funds, which are all listed on www.copsac.com. The Lundbeck Foundation, Danish State Budget, Danish Council for Strategic Research, Danish Council for Independent Research, and The Capital Region Research Foundation have provided core support for COPSAC. The study is further supported by the following National Institutes of Health grants: R01HL129735, R01HL141826, and UH3OD023268. C.E.W. acknowledges support from the Swedish Heart Lung Foundation (HLF 20200693 and HLF 20210519) and the Swedish Research Council (2022-00796). This project has received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 946228). R.S.K. was supported by the National Heart, Lung, and Blood Institute (HKL146980). Disclosure of potential conflict of interest: The authors declare that they have no relevant conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Fungicides undergo rapid metabolism and are excreted in the urine. There are few methods for screening these ubiquitous compounds, which have a high potential for human exposure. High-resolution mass spectrometry (HRMS) is a suitable technique to assess fungicide exposures; however, there is a lack of spectral libraries for fungicide annotation and in particular for downstream metabolites. We created spectral libraries for 32 fungicides for suspect screening. Fungicide standards were administered to mice, and 24-h urine was analyzed using hydrophilic interaction and reversed-phase chromatography coupled to hybrid quadrupole-orbitrap mass spectrometry. Suspect metabolite MS2 spectra for library creation were selected based on the ratio of exposed-to-control mouse urine. MS2 libraries were applied to urine collected from female university students ( n = 73). Several tetraconazole and tebuconazole metabolites were detected in 3% (2/73) of the samples. The creation of comprehensive suspect screening MS2 libraries is a useful tool to detect fungicide exposure for human biomonitoring.

Background: Bilirubin has antioxidant properties, and elevated levels within the normal range have been associated with improved lung function and decreased risk of asthma in adults, but studies of young children are scarce. Here, we investigate associations between bilirubin in early life and respiratory health endpoints during preschool age in two independent birth cohorts., Methods: Bilirubin metabolites were assessed at ages 0.5, 1.5, and 6 years in COPSAC 2010 (Copenhagen Prospective Studies on Asthma in Childhood 2010) and ages 1, 3, and 6 years in the VDAART (The Vitamin D Antenatal Asthma Reduction Trial) cohort. Meta-analyses were done to summarize the relationship between levels of bilirubin metabolites and asthma, infections, lung function, and allergic sensitization until age 6 across the cohorts. Interaction with the glucuronosyltransferase family 1 member A1 (UGT1A) genotype encoding for an enzyme in the bilirubin metabolism was explored, and metabolomics data were integrated to study underlying mechanisms., Findings: Increasing bilirubin (Z,Z) at ages 1.5-3 years was associated with an increased risk of allergic sensitization (adjusted relative risk [aRR] = 1.85 [1.20-2.85], p = 0.005), and age 6 bilirubin (Z,Z) also showed a trend of association with allergic sensitization at age 6 (aRR = 1.31 [0.97-1.77], p = 0.08), which showed significant interaction for the age 6 bilirubin (Z,Z)xUGT1A genotype. Further, increasing bilirubin (E,E), bilirubin (Z,Z), and biliverdin at ages 1.5-3 years was associated with a lower forced expiratory volume at age 6 (aRR range = 0.81-0.91, p < 0.049) but without a significant interaction with the UGT1A genotype (p interactions > 0.05). Network analysis showed a significant correlation between bilirubin metabolism and acyl carnitines. There were no associations between bilirubin metabolites and the risk of asthma and infections., Conclusions: Bilirubin metabolism in early life may play a role in childhood respiratory health, particularly in children with specific UGT1A genotypes., Funding: The Lundbeck Foundation (Grant no R16-A1694), The Ministry of Health (Grant no 903516), Danish Council for Strategic Research (Grant no 0603-00280B), and The Capital Region Research Foundation have provided core support to the COPSAC research center. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No. 946228). The Vitamin D Antenatal Asthma Reduction Trial (VDDART, ClinicalTrials.gov identifier: NCT00920621) was supported by grant U01HL091528 from NHLBI, U54TR001012 from the National Centers for Advancing Translational Sciences (NCATS). Metabolomics work by VDAART was supported by the National Heart, Lung, and Blood Institute (NHLBI) grant R01HL123915 and R01HL141826. S.T.W. was supported by R01HL091528 from the NHLBI, UG3OD023268 from Office of The Director, National Institute of Health, and P01HL132825 from the NHLBI., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: There is limited evidence on biomarkers associated with response to the monoclonal antibodies currently approved for asthma treatment. We sought to identify circulatory metabolites associated with response to treatment with mepolizumab or omalizumab., Methods: We conducted global metabolomic profiling of pre-treatment plasma samples from 100 patients with moderate-to-severe asthma who initiated mepolizumab (n=31) or omalizumab (n=69). The primary outcome was the change in exacerbations within 12 months of therapy. Negative binomial models were used to assess the association between each metabolite and exacerbations, adjusting for age, sex, body mass index, baseline exacerbations and inhaled corticosteroid use. Chemical similarity enrichment analysis (ChemRICH) was conducted to identify chemical subclasses associated with treatment response., Results: The mean age of the mepolizumab group was 58.7 years with on average 2.9 exacerbations over the year prior to initiation of biologic therapy. The mean age in the omalizumab group was 48.8 years with 1.5 exacerbations in the preceding year. Patients with higher levels of two tocopherol metabolites were associated with more exacerbations on mepolizumab (δ-carboxyethyl hydroxychroman (CEHC) (p=2.65E-05, false discovery rate (FDR=0.01) and δ-CEHC glucuronide (p=2.47E-06, FDR=0.003)). Higher levels of six androgenic steroids, three carnitine metabolites and two bile acid metabolites were associated with decreased exacerbations in the omalizumab group. In enrichment analyses, xanthine metabolites (cluster FDR=0.0006) and tocopherol metabolites (cluster FDR=0.02) were associated with worse mepolizumab response, while androgenic steroids (cluster FDR=1.9E-18), pregnenolone steroids (cluster p=3.2E-07, FDR=1.4E-05) and secondary bile acid metabolites (cluster p=0.0003, FDR=0.006) were the top subclasses associated with better omalizumab response., Conclusion: This study identifies distinct metabolites associated with response to mepolizumab and omalizumab, with androgenic steroids associated with response to both mepolizumab and omalizumab., Competing Interests: Conflict of interest: All authors have no relevant conflicts of interest to disclose. S.T. Weiss receives royalties from UpToDate and is on the Board of Histolix, a digital pathology company., (Copyright ©The authors 2024.)

Maintenance of NAD pools is critical for neuronal survival. The capacity to maintain NAD pools declines in neurodegenerative disease. We identify that low NMNAT2, the critical neuronal NAD producing enzyme, drives retinal susceptibility to neurodegenerative insults. As proof of concept, gene therapy over-expressing full length human NMNAT2 is neuroprotective. To pharmacologically target NMNAT2, we identify that epigallocatechin gallate (EGCG) can drive NAD production in neurons through an NMNAT2 and NMN dependent mechanism. We confirm this by pharmacological and genetic inhibition of the NAD-salvage pathway. EGCG is neuroprotective in rodent (mixed sex) and human models of retinal neurodegeneration. As EGCG has poor drug-like qualities, we use it as a tool compound to generate novel small molecules which drive neuronal NAD production and provide neuroprotection. This class of NMNAT2 targeted small molecules could have an important therapeutic impact for neurodegenerative disease following further drug development., (© 2024. The Author(s).)

Weight loss is often followed by weight regain. Characterizing endocrine alterations accompanying weight reduction and regain may disentangle the complex biology of weight-loss maintenance. Here, we profile energy-balance-regulating metabokines and sphingolipids in adults with obesity undergoing an initial low-calorie diet-induced weight loss and a subsequent weight-loss maintenance phase with exercise, glucagon-like peptide-1 (GLP-1) analog therapy, both combined, or placebo. We show that circulating growth differentiation factor 15 (GDF15) and C16:0-C18:0 ceramides transiently increase upon initial diet-induced weight loss. Conversely, circulating fibroblast growth factor 21 (FGF21) is downregulated following weight-loss maintenance with combined exercise and GLP-1 analog therapy, coinciding with increased adiponectin, decreased leptin, and overall decrements in ceramide and sphingosine-1-phosphate levels. Subgroup analyses reveal differential alterations in FGF21-adiponectin-leptin-sphingolipids between weight maintainers and regainers. Clinically, cardiometabolic health outcomes associate with selective metabokine-sphingolipid remodeling signatures. Collectively, our findings indicate distinct FGF21, GDF15, and ceramide responses to diverse phases of weight change and suggest that weight-loss maintenance involves alterations within the metabokine-sphingolipid axis., Competing Interests: Declaration of interests A family member of R.M.S. holds Novo Nordisk stocks. S.M. is on advisory boards of AstraZeneca, Boehringer Ingelheim, Eli Lilly, Merck Sharp & Dohme, Novo Nordisk, and Sanofi Aventis; receives lecture fees from AstraZeneca, Boehringer Ingelheim, Merck Sharp & Dohme, Novo Nordisk, and Sanofi Aventis; and is a research grant recipient from Novo Nordisk and Boehringer Ingelheim. J.J.H. is on the advisory board of Novo Nordisk. S.S.T. is a research grant recipient and receives lecture fees from Novo Nordisk., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Tobacco smoking is the main etiological factor of lung cancer (LC), which can also cause metabolome disruption. This study aimed to investigate whether the observed metabolic shift in LC patients was also associated with their smoking status. Untargeted metabolomics profiling was applied for the initial screening of changes in serum metabolic profile between LC and chronic obstructive pulmonary disease (COPD) patients, selected as a non-cancer group. Differences in metabolite profiles between current and former smokers were also tested. Then, targeted metabolomics methods were applied to verify and validate the proposed LC biomarkers. For untargeted metabolomics, a single extraction-dual separation workflow was applied. The samples were analyzed using a liquid chromatograph-high resolution quadrupole time-of-flight mass spectrometer. Next, the selected metabolites were quantified using liquid chromatography-triple-quadrupole mass spectrometry. The acquired data confirmed that patients' stratification based on smoking status impacted the discriminating ability of the identified LC marker candidates. Analyzing a validation set of samples enabled us to determine if the putative LC markers were truly robust. It demonstrated significant differences in the case of four metabolites: allantoin, glutamic acid, succinic acid, and sphingosine-1-phosphate. Our research showed that studying the influence of strong environmental factors, such as tobacco smoking, should be considered in cancer marker research since it reduces the risk of false positives and improves understanding of the metabolite shifts in cancer patients., (© 2024. The Author(s).)

Introduction: We tested the hypothesis that a carbohydrate (CHO: 6.5%) or carbohydrate-electrolyte (CHO + E: 6.5% + 50 mmol/L NaCl) drink would better recover plasma volume (PV) and exercise performance compared to water (H2O) after immersion diuresis., Methods: Twelve men (24 ± 2 years; 82.4 ± 15.5 kg; and V̇O2max: 49.8 ± 5.1 mL · kg-1 · min-1) completed four experimental visits: a no-immersion control (CON) and three 4-h cold-water (18.0 °C) immersion trials (H2O, CHO, and CHO + E) followed by exercise in a warm environment (30 °C, 50% relative humidity). The exercise was a 60-minute loaded march (20.4 kg; 55% VO2max) followed by a 10-minute intermittent running protocol. After immersion, subjects were rehydrated with 100% of body mass loss from immersion diuresis during the ruck march. PV is reported as a percent change after immersion, after the ruck march, and after the intermittent running protocol. The intermittent running protocol distance provided an index of exercise performance. Data are reported as mean ± SD., Results: After immersion, body mass loss was 2.3 ± 0.7%, 2.3 ± 0.5%, and 2.3 ± 0.6% for H2O, CHO, and CHO + E. PV loss after immersion was 19.8 ± 8.5% in H2O, 18.2 ± 7.0% in CHO, and 13.9 ± 9.3% in CHO + E, which was reduced after the ruck march to 14.7 ± 4.7% (P = .13) in H2O, 8.8 ± 8.3% (P < .01) in CHO, and 4.4 ± 10.9% (P = .02) in CHO + E. The intermittent running protocol distance was 1.4 ± 0.1 km in CON, 1.4 ± 0.2 km in H2O, 1.4 ± 0.1 km in CHO, and 1.4 ± 0.2 km in CHO + E (P = .28)., Conclusions: Although CHO and CHO + E better restored PV after immersion, post-immersion exercise performance was not augmented compared to H2O, highlighting that fluid replacement following immersion diuresis should focus on restoring volume lost rather than fluid constituents., (© The Association of Military Surgeons of the United States 2023. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: The immunometabolic mechanisms underlying variable responses to oral immunotherapy (OIT) in patients with IgE-mediated food allergy are unknown., Objective: To identify novel pathways associated with tolerance in food allergy, we used metabolomic profiling to find pathways important for food allergy in multi-ethnic cohorts and responses to OIT., Methods: Untargeted plasma metabolomics data were generated from the VDAART healthy infant cohort (N=384), a Costa Rican cohort of children with asthma (N=1040), and a peanut OIT trial (N=20) evaluating sustained unresponsiveness (SU, protection that lasts after therapy) versus transient desensitization (TD, protection that ends immediately afterwards). Generalized linear regression modeling and pathway enrichment analysis identified metabolites associated with food allergy and OIT outcomes., Results: Compared with unaffected children, those with food allergy were more likely to have metabolomic profiles with altered histidines and increased bile acids. Eicosanoids (e.g., arachidonic acid derivatives) (q=2.4×10 -20 ) and linoleic acid derivatives (q=3.8×10 -5 ) pathways decreased over time on OIT. Comparing SU versus TD revealed differing concentrations of bile acids (q=4.1×10 -8 ), eicosanoids (q=7.9×10 -7 ), and histidine pathways (q=0.015). In particular, the bile acid lithocholate (4.97[1.93,16.14], p=0.0027), the eicosanoid leukotriene B4 (3.21[1.38,8.38], p=0.01), and the histidine metabolite urocanic acid (22.13[3.98,194.67], p=0.0015) were higher in SU., Conclusions: We observed distinct profiles of bile acids, histidines, and eicosanoids that vary among patients with food allergy, over time on OIT and between SU and TD. Participants with SU had higher levels of metabolites such as lithocholate and urocanic acid, which have immunomodulatory roles in key T-cell subsets, suggesting potential mechanisms of tolerance in immunotherapy., Key Messages: - Compared with unaffected controls, children with food allergy demonstrated higher levels of bile acids and distinct histidine/urocanic acid profiles, suggesting a potential role of these metabolites in food allergy. - In participants receiving oral immunotherapy for food allergy, those who were able to maintain tolerance-even after stopping therapyhad lower overall levels of bile acid and histidine metabolites, with the exception of lithocholic acid and urocanic acid, two metabolites that have roles in T cell differentiation that may increase the likelihood of remission in immunotherapy., Capsule Summary: This is the first study of plasma metabolomic profiles of responses to OIT in individuals with IgE-mediated food allergy. Identification of immunomodulatory metabolites in allergic tolerance may help identify mechanisms of tolerance and guide future therapeutic development.

Metabolomic epidemiology studies are complex and require a broad array of domain expertise. Although many metabolite-phenotype associations have been identified; to date, few findings have been translated to the clinic. Bridging this gap requires understanding of both the underlying biology of these associations and their potential clinical implications, necessitating an interdisciplinary team approach. To address this need in metabolomic epidemiology, a workshop was held at Metabolomics 2023 in Niagara Falls, Ontario, Canada that highlighted the domain expertise needed to effectively conduct these studies -- biochemistry, clinical science, epidemiology, and assay development for biomarker validation -- and emphasized the role of interdisciplinary teams to move findings towards clinical translation., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply 2024.)

Background: Lung function trajectories (LFTs) have been shown to be an important measure of long-term health in asthma. While there is a growing body of metabolomic studies on asthma status and other phenotypes, there are no prospective studies of the relationship between metabolomics and LFTs or their genomic determinants., Methods: We utilized ordinal logistic regression to identify plasma metabolite principal components associated with four previously-published LFTs in children from the Childhood Asthma Management Program (CAMP) (n = 660). The top significant metabolite principal component (PC LF ) was evaluated in an independent cross-sectional child cohort, the Genetic Epidemiology of Asthma in Costa Rica Study (GACRS) (n = 1151) and evaluated for association with spirometric measures. Using meta-analysis of CAMP and GACRS, we identified associations between PC LF and microRNA, and SNPs in their target genes. Statistical significance was determined using an false discovery rate-adjusted Q-value., Findings: The top metabolite principal component, PC LF , was significantly associated with better LFTs after multiple-testing correction (Q-value = 0.03). PC LF is composed of the urea cycle, caffeine, corticosteroid, carnitine, and potential microbial (secondary bile acid, tryptophan, linoleate, histidine metabolism) metabolites. Higher levels of PC LF were also associated with increases in lung function measures and decreased circulating neutrophil percentage in both CAMP and GACRS. PC LF was also significantly associated with microRNA miR-143-3p, and SNPs in three miR-143-3p target genes; CCZ1 (P-value = 2.6 × 10 -5 ), SLC8A1 (P-value = 3.9 × 10 -5 ); and TENM4 (P-value = 4.9 × 10 -5 )., Interpretation: This study reveals associations between metabolites, miR-143-3p and LFTs in children with asthma, offering insights into asthma physiology and possible interventions to enhance lung function and long-term health., Funding: Molecular data for CAMP and GACRS via the Trans-Omics in Precision Medicine (TOPMed) program was supported by the National Heart, Lung, and Blood Institute (NHLBI)., Competing Interests: Declaration of interests JLS is a scientific advisor to Precion, Inc., receives grants and consulting fees from TruDiagnostic and Ahara Corp, and holds patents with TruDiagnostic. KLS is employed by Vertex Pharmaceuticals. STW is a board member of Histolix and receives royalties from UpToDate. All other authors declare no potential, perceived, or real conflict of interest regarding the content of this manuscript., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Introduction: V̇O 2 drift, the rise in oxygen consumption during continuous exercise, has not been adequately reported during prolonged military marches. The purpose of this study was to analyse V̇O 2 and energy expenditure (EE) during a loaded march with and without rehydration efforts. Second, the study aimed to compare EE throughout the march with predicted values using a validated model., Methods: Seven healthy men (23±2 years; V̇O 2max : 50.8±5.3 mL/kg/min) completed four 60 min loaded marches (20.4 kg at 50% V̇O 2max ) in a warm environment (30°C and 50% relative humidity). Three were preceded by hypohydration via a 4-hour cold water immersion (18°C). The control (CON) visit was a non-immersed euhydrated march. After water immersion, subjects were rehydrated with 0% (NO), 50% (HALF) or 100% (FULL) of total body mass lost. During exercise, V̇O 2 and EE were collected and core temperature change was calculated. To determine if EE could be accurately predicted, values were compared with a calculated estimate using the US Army Load Carry Decision Aid (LCDA)., Results: At the start of exercise, there was no difference between conditions in V̇O 2 (ALL: 24.3±0.3 mL/kg/min; p=0.50) or EE (ALL: 8.6±1.0 W/kg; p=0.68). V̇O 2 (p=0.02) and EE (p<0.01) increased during exercise and were 12.3±10.0% and 12.8±9.5% greater, respectively, at 60 min across all trials and were not mitigated by rehydration amount. There was an effect of core temperature change on V̇O 2 for each condition (CON: r=0.62; NO: r=0.47; HALF: r=0.70; FULL: r=0.55). LCDA-predicted values were different from measured EE during exercise., Conclusion: V̇O 2 drift occurred during loaded military marches and was associated with increases in EE and core temperature change. Pre-exercise hypohydration with water immersion followed by rehydration did not influence the degree of drift. LCDA prediction of EE may not agree with measured values during prolonged loaded marches where V̇O 2 drift occurs., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Bronchopulmonary Dysplasia (BPD) in infants born prematurely is a risk factor for chronic airway obstruction later in life. The distribution of T cell subtypes in the large airways is largely unknown., Objective: To characterize cellular and T cell profiles in the large airways of young adults with a history of BPD., Methods: Forty-three young adults born prematurely (preterm (n = 20), BPD (n = 23)) and 45 full-term-born (asthma (n = 23), healthy (n = 22)) underwent lung function measurements, and bronchoscopy with large airway bronchial wash (BW). T-cells subsets in BW were analyzed by immunocytochemistry., Results: The proportions of both lymphocytes and CD8 + T cells in BW were significantly higher in BPD (median, 6.6%, and 78.0%) when compared with asthma (3.4% and 67.8%, p = 0.002 and p = 0.040) and healthy (3.8% and 40%, p < 0.001 and p < 0.001). In all adults born prematurely (preterm and BPD), lymphocyte proportion correlated negatively with forced vital capacity (r= -0.324, p = 0.036) and CD8 + T cells correlated with forced expiratory volume in one second, FEV 1 (r=-0.448, p = 0.048). Correlation-based network analysis revealed that lung function cluster and BPD-birth cluster were associated with lymphocytes and/or CD4 + and CD8 + T cells. Multivariate regression analysis showed that lymphocyte proportions and BPD severity qualified as independent factors associated with FEV 1 ., Conclusions: The increased cytotoxic T cells in the large airways in young adults with former BPD, suggest a similar T-cell subset pattern as in the small airways, resembling features of COPD. Our findings strengthen the hypothesis that mechanisms involving adaptive and innate immune responses are involved in the development of airway disease due to preterm birth., (© 2024. The Author(s).)

Abstract: Wheelock, CE, Stooks, J, Schwob, J, Hess, HW, Pryor, RR, and Hostler, D. Partial and complete fluid replacement maintains exercise performance in a warm environment following prolonged cold-water immersion. J Strength Cond Res 38(2): 290-296, 2024-Special warfare operators may be exposed to prolonged immersion before beginning a land-based mission. This immersion will result in substantial hypohydration because of diuresis. This study tested the hypothesis that both partial and full postimmersion rehydration would maintain performance during exercise in the heat. Seven men (23 ± 2 years; V̇o2max: 50.8 ± 5.3 ml·kg-1·min-1) completed a control trial (CON) without prior immersion and 3 immersion (18.0°C) trials without rehydration (NO) or with partial (HALF) or full (FULL) rehydration. After immersion, subjects completed a 60-minute weighted ruck march (20.4 kg; 5.6 kph) and a 15-minute intermittent exercise protocol (iEPT) in a warm environment (30.0°C and 50.0% relative humidity). The primary outcome was distance (km) covered during the iEPT. A priori statistical significance was set to p ≤ 0.05. Immersion resulted in 2.3 ± 0.4% loss of body mass in all immersion trials (p < 0.01). Distance covered during the first 13-minute interval run portion of iEPT was reduced in the NO rehydration trial (1.59 ± 0.18 km) compared with all other conditions (CON: 1.88 ± 0.18 km, p = 0.03; HALF: 1.80 ± 0.18 km, p < 0.01; FULL: 1.86 ± 0.28 km, p = 0.01). During the final 2 minutes of the iEPT, distance in the NO rehydration trial (0.31 ± 0.07 km) was reduced compared with the FULL rehydration trial (0.37 ± 0.07 km; p < 0.01) but not compared with CON (0.35 ± 0.07 km; p = 0.09) or HALF (0.35 ± 0.07 km; p = 0.08). Both partial and full postimmersion fluid replacement maintained intermittent exercise performance and should be applied as rehydration strategies., (Copyright © 2023 National Strength and Conditioning Association.)

Background: Oxylipins are products derived from polyunsaturated fatty acids (PUFAs) that play a role in cardiovascular disease and aging. Fish oil-derived n-3 PUFAs promote the formation of anti-inflammatory and vasodilatory oxylipins; however, there are little data on oxylipins derived from α-linolenic acid (C18:3n-3), the primary plant-derived n-3 PUFA. Walnuts are a source of C18:3n-3., Objectives: To investigate the effect on serum oxylipins of a diet enriched with walnuts at 15% energy (30-60 g/d; 2.6-5.2 g C18:3n-3/d) for 2 y compared to a control diet (abstention from walnuts) in healthy older males and females (63-79 y)., Methods: The red blood cell proportion of α-linolenic acid was determined by gas chromatography as a measure of compliance. Ultra-performance liquid chromatography-tandem mass spectrometry was used to measure serum concentrations of 53 oxylipins in participants randomly assigned to receive the walnut diet (n = 64) or the control diet (n = 51). Two-year concentration changes (final minus baseline) were log-transformed (base log-10) and standardized (mean-centered and divided by the standard deviation of each variable). Volcano plots were then generated (fold change ≥1.5; false discovery rate ≤0.1). For each oxylipin delta surviving multiple testing, we further assessed between-intervention group differences by analysis of covariance adjusting for age, sex, BMI, and the baseline concentration of the oxylipin., Results: The 2-y change in red blood cell C18:3n-3 in the walnut group was significantly higher than that in the control group (P < 0.001). Compared to the control diet, the walnut diet resulted in statistically significantly greater increases in 3 C18:3n-3-derived oxylipins (9-HOTrE, 13-HOTrE, and 12,13-EpODE) and in the C20:5n-3 derived 14,15-diHETE, and greater reductions of the C20:4n-6-derived 5-HETE, 19-HETE, and 5,6-diHETrE., Conclusions: Long-term walnut consumption changes the serum oxylipin profile in healthy older persons. Our results add novel mechanistic evidence on the cardioprotective effects of walnuts., Trial Registration: Clinicaltrials.gov Identifier: NCT01634841., (Copyright © 2023 American Society for Nutrition. Published by Elsevier Inc. All rights reserved.)

Background: While dysregulated sphingolipid metabolism has been associated with risk of childhood asthma, the specific sphingolipid classes and/or mechanisms driving this relationship remain unclear. We aimed to understand the multifaceted role between sphingolipids and other established asthma risk factors that complicate this relationship., Methods: We performed targeted LC-MS/MS-based quantification of 77 sphingolipids in plasma from 997 children aged 6 years from two independent cohorts (VDAART and COPSAC 2010 ). We examined associations of circulatory sphingolipids with childhood asthma, lung function, and three asthma risk factors: functional SNPs in ORMDL3, low vitamin D levels, and reduced gut microbial maturity. Given racial differences between these cohorts, association analyses were performed separately and then meta-analyzed together., Results: We observed elevations in circulatory sphingolipids with asthma phenotypes and risk factors; however, there were differential associations of sphingolipid classes with clinical outcomes and/or risk factors. While elevations from metabolites involved in ceramide recycling and catabolic pathways were associated with asthma and worse lung function [meta p-value range: 1.863E-04 to 2.24E-3], increased ceramide levels were associated with asthma risk factors [meta p-value range: 7.75E-5 to .013], but not asthma. Further investigation identified that some ceramides acted as mediators while some interacted with risk factors in the associations with asthma outcomes., Conclusion: This study demonstrates the differential role that sphingolipid subclasses may play in asthma and its risk factors. While overall elevations in sphingolipids appeared to be deleterious overall; elevations in ceramides were uniquely associated with increases in asthma risk factors only; while elevations in asthma phenotypes were associated with recycling sphingolipids. Modification of asthma risk factors may play an important role in regulating sphingolipid homeostasis via ceramides to affect asthma. Further function work may validate the observed associations., (© 2023 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Urinary eicosanoid concentrations reflect inflammatory processes in multiple diseases and have been used as biomarkers of disease as well as suggested for patient stratification in precision medicine. However, implementation of urinary eicosanoid profiling in large-scale analyses is restricted due to sample preparation limits. Here we demonstrate a single solid-phase extraction of 300 µL urine in 96-well-format for prostaglandins, thromboxanes, isoprostanes, cysteinyl-leukotriene E 4 and the linoleic acid-derived dihydroxy-octadecenoic acids (9,10- and 12,13-DiHOME). A simultaneous screening protocol was also developed for cortisol/cortisone and 7 exogenous steroids as well as 3 cyclooxygenase inhibitors. Satisfactory performance for quantification of eicosanoids with an appropriate internal standard was demonstrated for intra-plate analyses (CV = 8.5-15.1%) as well as for inter-plate (n = 35) from multiple studies (CV = 22.1-34.9%). Storage stability was evaluated at - 20 °C, and polar tetranors evidenced a 50% decrease after 5 months, while the remaining eicosanoids evidenced no significant degradation. All eicosanoids were stable over 3.5-years in urine stored at - 80 °C. This method will facilitate the implementation of urinary eicosanoid quantification in large-scale screening., Competing Interests: Declaration of Competing Interest JK receives consulting fees from Gesynta Pharma AB., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Gestational vitamin D deficiency is implicated in development of respiratory diseases in offspring, but the mechanism underlying this relationship is unknown., Objective: We sought to study the link between gestational vitamin D exposure and childhood asthma phenotypes using maternal blood metabolomics profiling., Methods: Untargeted blood metabolic profiles were acquired using liquid chromatography-mass spectrometry at 1 week postpartum from 672 women in the Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC 2010 ) mother-child cohort and at pregnancy weeks 32 to 38 from 779 women in the Vitamin D Antenatal Asthma Reduction Trial (VDAART) mother-child cohort. In COPSAC 2010 , we employed multivariate models and pathway enrichment analysis to identify metabolites and pathways associated with gestational vitamin D blood levels and investigated their relationship with development of asthma phenotypes in early childhood. The findings were validated in VDAART and in cellular models., Results: In COPSAC 2010 , higher vitamin D blood levels at 1 week postpartum were associated with distinct maternal metabolome perturbations with significant enrichment of the sphingomyelin pathway (P < .01). This vitamin D-related maternal metabolic profile at 1 week postpartum containing 46 metabolites was associated with decreased risk of recurrent wheeze (hazard ratio [HR] = 0.92 [95% CI 0.86-0.98], P = .01) and wheeze exacerbations (HR = 0.90 [95% CI 0.84-0.97], P = .01) at ages 0 to 3 years. The same metabolic profile was similarly associated with decreased risk of asthma/wheeze at ages 0 to 3 in VDAART (odds ratio = 0.92 [95% CI 0.85-0.99], P = .04). Human bronchial epithelial cells treated with high-dose vitamin D 3 showed an increased cytoplasmic sphingolipid level (P < .01)., Conclusions: This exploratory metabolomics study in 2 independent birth cohorts demonstrates that the beneficial effect of higher gestational vitamin D exposure on offspring respiratory health is characterized by specific maternal metabolic alterations during pregnancy, which involves the sphingomyelin pathway., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Asthma is the most common chronic disease within the paediatric population. Although it is multifactorial, its onset may be linked to early-life exposures with subsequent impact on immune system development. Microbial and dietary metabolic products have been implicated in the development and exacerbation of paediatric asthma. Linoleic acid is the most common omega-6 polyunsaturated fatty acid in the Western diet. In this review, we summarise the literature regarding the involvement of linoleic acid in the development of and its impact on existing paediatric asthma. First, we summarise the existing knowledge surrounding the relationship between human microbial metabolism and allergic diseases in children. Next, we examine cellular or animal model-based mechanistic studies that investigated the impact of dietary- and microbial-derived linoleic acid metabolites on asthma. Finally, we review the literature investigating the impact of linoleic acid metabolites on the development and exacerbation of childhood asthma. While there is conflicting evidence, there is growing support for a role of linoleic acid in the onset and pathophysiology of asthma. We recommend that additional cellular, animal, and longitudinal studies are performed that target linoleic acid and its metabolites., Competing Interests: Conflict of interest: All authors have nothing to disclose., (Copyright ©The authors 2023.)