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Cannabis use disorder affects up to 42% of individuals with schizophrenia, correlating with earlier onset, increased positive symptoms, and more frequent hospitalizations. This study employed an untargeted lipidomics approach to identify biomarkers in plasma samples from subjects with schizophrenia, cannabis use disorder, or both (dual diagnosis), aiming to elucidate the metabolic underpinnings of cannabis abuse and schizophrenia development. The use of liquid chromatography-high resolution mass spectrometry enabled the annotation of 119 metabolites, with the highest identification confidence level achieved for 16 compounds. Notably, a marked reduction in acylcarnitines, including octanoylcarnitine and decanoylcarnitine, was observed across all patient groups compared to controls. In cannabis use disorder patients, N-acyl amino acids (NAAAs), particularly N-palmitoyl threonine and N-palmitoyl serine, showed a strong downregulation, a pattern also seen in schizophrenia and dual diagnosis patients. Conversely, elevated levels of 7-dehydrodesmosterol were detected in schizophrenia and dual diagnosis patients relative to controls. These findings suggest a potential link between metabolic disruptions and the pathophysiology of both disorders. The untargeted lipidomics approach offers a powerful tool to identify novel biomarkers, enhancing our understanding of the biological relationship between cannabis abuse and schizophrenia, and paving the way for future therapeutic strategies targeting metabolic pathways in these conditions. [ABSTRACT FROM AUTHOR]

From a detailed review of 90 experimental and clinical metabolomic investigations of obesity and metabolic dysfunction-associated steatotic liver disease (MASLD), we have developed metabolomic hallmarks for both obesity and MASLD. Obesity studies were conducted in mice, rats, and humans, with consensus biomarker groups in plasma/serum being essential and nonessential amino acids, energy metabolites, gut microbiota metabolites, acylcarnitines and lysophosphatidylcholines (LPC), which formed the basis of the six metabolomic hallmarks of obesity. Additionally, mice and rats shared elevated cholesterol, humans and rats shared elevated fatty acids, and humans and mice shared elevated VLDL/LDL, bile acids and phosphatidylcholines (PC). MASLD metabolomic studies had been performed in mice, rats, hamsters, cows, geese, blunt snout breams, zebrafish, and humans, with the biomarker groups in agreement between experimental and clinical investigations being energy metabolites, essential and nonessential amino acids, fatty acids, and bile acids, which lay the foundation of the five metabolomic hallmarks of MASLD. Furthermore, the experimental group had higher LPC/PC and cholesteryl esters, and the clinical group had elevated acylcarnitines, lysophosphatidylethanolamines/phosphatidylethanolamines (LPE/PE), triglycerides/diglycerides, and gut microbiota metabolites. These metabolomic hallmarks aid in the understanding of the metabolic role played by obesity in MASLD development, inform mechanistic studies into underlying disease pathogenesis, and are critical for new metabolite-inspired therapies. [ABSTRACT FROM AUTHOR]

Summary An 18‐year‐old Saxon Warmblood gelding was referred to an equine clinic in the Czech Republic in May 2019 for mild colic. The horse had 7 h of grazing and 30–45 min of exercise every day. At the clinic, physical examination ruled out gastrointestinal disease, while clinical pathology confirmed rhabdomyolysis (creatine kinase 29,088 IU/L; reference range 110–250 IU/L). Because of the suspicion of atypical myopathy (AM), metabolomic analysis of hypoglycin A (HGA), 31 acylcarnitines (ACs) and free carnitine was performed in four dry serum and one blood spot. After laboratory confirmation of AM in the patient studied (HGA: 0.757–0.415 μmol/L, ACs elevation), an incriminated pasture was visited and searched for the source of the toxin. No sycamore (Acer pseudoplatanus) was found in the vicinity of the pasture. However, several box elder (Acer negundo) trees were found, and toxicological analysis revealed HGA in the samaras (7.66–296.00 mg/kg), leaves (2.12–9.39 mg/kg) and seedlings (339.00 mg/kg). Not only sycamore but also the box elder tree can be a potential source of poisoning in horses in Europe, particularly in lowland areas with a warm climate. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) pathogenesis involves dysregulation in diverse biochemical processes. Nevertheless, plasma tau phosphorylated at threonine 181 (P‐tau181), a recognised AD biomarker, has been described to reflect early‐stage cortical amyloid‐β (Aβ) deposition in cognitively normal (CN) adults. Therefore, identifying changes in plasma metabolites associated with plasma P‐tau181 at the pre‐clinical stage may provide insights into underlying biochemical mechanisms to better understand initial AD pathogenesis. In the current study, plasma P‐tau181, quantified via single molecule array (Simoa) technology, and plasma metabolites, quantified via targeted‐mass spectrometry, were investigated for associations in CN older adults and upon stratification by positron emission tomography (PET)‐Aβ load. In addition, the P‐tau181‐linked metabolites were evaluated for cognitive performance and neuroimaging markers of AD and the potential to distinguish between CN Aβ− and CN Aβ+ individuals. Significant positive associations of medium‐ and long‐chain acylcarnitines (ACs) were observed with P‐tau181 in the entire cohort, CN Aβ− and CN Aβ+, suggesting a link between initial Aβ pathology and fatty acid oxidation‐mediated energy metabolism pathways. However, in CN Aβ−, additional linear associations of P‐tau181 were observed with muscle metabolism and nitric oxide homeostasis‐associated metabolites. Upon investigating the P‐tau181‐linked metabolites for cognitive performance, significant inverse correlations of the verbal and visual episodic memory and the global composite score were noted in CN Aβ+ with medium‐ and long‐chain ACs, suggesting prognostic value of ACs accompanying weaker cognitive performance. While investigating neuroimaging markers, ACs had positive associations with PET‐Aβ load and inverse associations with hippocampal volume in CN Aβ+, indicating connections of ACs with initial AD pathogenesis. Furthermore, based on receiver operating characteristics analysis, the associated ACs potentially classified PET‐Aβ status in older adults. Therefore, plasma P‐tau181‐linked circulating ACs may serve as potential prognostic markers for initial AD pathogenesis in CN older adults. However, further cross‐sectional and longitudinal research in highly characterised AD cohorts is needed to validate current findings. [ABSTRACT FROM AUTHOR]

To improve the interpretation and utilisation of blood lipids, ketones and acylcarnitine concentrations as biomarkers in clinical assessments, more information is needed on their dynamic alterations in response to dietary intake and fasting. The aim of this intervention study was to characterise the changes in serum lipid, ketone and acylcarnitine concentrations 24 h after a standardised breakfast meal. Thirty-four healthy subjects (eighteen males and sixteen females) aged 20–30 years were served a breakfast meal (∼500 kcal, 36 E% fat, 46 E% carbohydrates, 16 E% protein, 2E% fibre), after which they consumed only water for 24 h. Blood samples were drawn before and at thirteen standardised timepoints after the meal. Metabolite concentrations were plotted as a function of time since the completion of the breakfast meal. Results demonstrated that concentrations of HDL-cholesterol and LDL-cholesterol decreased until ∼2 h (–4 % for both), while TAG concentrations peaked at 3 h (+27 %). Acetoacetate and β -hydroxybutyrate were highest 24 h after the meal (+433 and +633 %, respectively). Acetylcarnitine, butyrylcarnitine, hexanoylcarnitine, octanoylcarnitine, decanoylcarnitine and dodecanoylcarnitine reached the lowest values at 60 min (decreases ranging from –47 to –70 %), before increasing and peaking at 24 h after the meal (increases ranging from +86 to +120 %). Our findings suggest that distinguishing between fasting and non-fasting blood samples falls short of capturing the dynamics in lipid, ketone, carnitine and acylcarnitine concentrations. To enhance the utility of serum acylcarnitine analyses, we strongly recommend accounting for the specific time since the last meal at the time of blood sampling. [ABSTRACT FROM AUTHOR]

Introduction: The human immunodeficiency virus (HIV) and tuberculosis (TB) co-infection presents significant challenges due to the complex interplay between these diseases, leading to exacerbated metabolic disturbances. Understanding these metabolic profiles is crucial for improving diagnostic and therapeutic approaches. Objective: This study aimed to characterise the urinary acylcarnitine and amino acid profiles, including 5-hydroxyindoleacetic acid (5-HIAA), in patients co-infected with HIV and TB using targeted liquid chromatography mass spectrometry (LC–MS) metabolomics. Methods: Urine samples, categorised into HIV, TB, HIV/TB co-infected, and healthy controls, were analysed using HPLC–MS/MS. Statistical analyses included one-way ANOVA and a Kruskal-Wallis test to determine significant differences in the acylcarnitine and amino acid profiles between groups. Results: The study revealed significant metabolic alterations, especially in TB and co-infected groups. Elevated levels of medium-chain acylcarnitines indicated increased fatty acid oxidation, commonly associated with cachexia in TB. Altered amino acid profiles suggested disruptions in protein and glucose metabolism, indicating a shift towards diabetes-like metabolic states. Notably, TB was identified as a primary driver of these changes, affecting protein turnover, and impacting energy metabolism in co-infected patients. Conclusion: The metabolic profiling of HIV/TB co-infection highlights the profound impact of TB on metabolic pathways, which may exacerbate the clinical complexities of co-infection. Understanding these metabolic disruptions can guide the development of targeted treatments and improve management strategies, ultimately enhancing the clinical outcomes for these patients. Further research is required to validate these findings and explore their implications in larger, diverse populations. [ABSTRACT FROM AUTHOR]

Breast cancer (BC) is among the most commonly diagnosed cancers. Besides mammography, breast ultrasonography and the routinely monitored protein markers, the variations of small molecular metabolites in blood may be of great diagnostic value. This study aimed to quantify specific metabolite markers with potential application in BC detection. The study enrolled 50 participants, 25 BC patients and 25 healthy controls (CTRL). Dried blood spots (DBS) were utilized as biological media and were quantified via a simplified liquid chromatography tandem mass spectrometry (LC-MS/MS) method, used in expanded newborn screening. The targeted metabolomic analysis included 12 amino acids and 32 acylcarnitines. Statistical analysis revealed a significant variation of metabolic profiles between BC patients and CTRL. Among the 44 metabolites, 18 acylcarnitines and 10 amino acids remained significant after Bonferroni correction, showing increase or decrease and enabled classification of BC patients and CTRL. The well-established LC-MS/MS protocol could provide results within few minutes. Therefore, the combination of an easy-to-handle material-DBS and LC-MS/MS protocol could facilitate BC screening/diagnosis and in the next step applied to other cancer patients, as well. [ABSTRACT FROM AUTHOR]

Objective: LC-MS/MS-based metabolomics is an important tool for studying disease-related biomarkers. Conventionally, different strategies have been used to screen biomarkers. However, many studies for biomarker screening by different strategies have ignored the dose-response relationship between the biomarker level and exposure level, and no relevant studies have described and compared different strategies in detail. Phenobarbital (PHB) which belongs to the barbiturates, was selected as the typical representative of neurotoxins. Acylcarnitines have been promising candidates for diagnostic biomarkers for several neurological disorders and neurotoxicity. In this work, we aimed to use an acute PHB poisoning animal model to clarify PHB poisoning effects on plasma and brain acylcarnitine changes and how to rationally analyze data from LCMS/ MS. Methods: The acylcarnitine profiles in plasma and brain regions in an actuate PHB poisoning animal model were utilized. The dose-response relationship between plasma PHB and carnitine and acylcarnitines (CARs) in plasma and brain were assessed by the variance analysis trend test and Spearman's rank correlation test. In different strategies, principal component analysis (PCA) and partial least squares discriminant analysis (OPLS-DA) screened the differential CARs, variable importance plots (VIPs) were utilized to select putative biomarkers for PHB-induced toxicity, and receiver operating characteristic (ROC) curve analysis then illustrated the reliability of biomarkers. Results: Under the first strategy, 14 potential toxicity biomarkers were obtained including eight downregulated CARs with AUC >0.8. Under the second strategy, 11 potential toxicity biomarkers were obtained containing five downregulated CARs with AUC >0.8. Only when the dose-response relationship was fully considered, different strategies screen for the same biomarkers (plasma acetyl-carnitine (C2) and plasma decanoyl-carnitine (C10)), which indicated plasma acylcarnitines might serve as toxicity biomarkers. In addition, the plasma CAR level changes showed differences from brain CAR level changes, and correlations between plasma CARs and their brain counterparts were weak. Conclusion: We found that plasma C2 and C10 might serve as toxicity biomarkers for PHB poisoning disorders, and PHB poisoning effects on changes in plasma CARs may not be fully representative of changes in brain CARs. [ABSTRACT FROM AUTHOR]

Background: Physiological changes of blood amino acids and acylcarnitines during healthy child development are poorly studied. The LIFE (Leipziger Forschungszentrum für Zivilisationserkrankungen) Child study offers a platform with a large cohort of healthy children to investigate these dynamics. We aimed to assess the intra-person variability of 28 blood metabolites and their associations with anthropometric parameters related to growth and excess body fat. Methods: Concentrations of 22 amino acids (AA), 5 acylcarnitines (AC) and free carnitine of 2213 children aged between 3 months and 19 years were analyzed using liquid chromatography/tandem mass spectrometry. Values were transformed into standard deviation scores (SDS) to account for sex- and age-related variations. The stability of metabolites was assessed through the coefficient of determination. Associations with parameters for body composition and insulin-like growth factor-I (IGF-I) SDS were determined by the Pearson correlation and linear regression. Results: Our research revealed substantial within-person variation in metabolite concentrations during childhood and adolescence. Most metabolites showed a positive correlation with body composition parameters, with a notable influence of sex, pubertal status and weight group. Glycine exhibited negative associations with parameters of body fat distribution, especially in normal weight girls, overweight/obese boys and during puberty. Conclusion: Blood AA and AC measurements may contribute to elucidating pathogenesis pathways of adiposity-related comorbidities, but the specific timings and conditions of development during childhood and adolescence need to be taken into consideration. [ABSTRACT FROM AUTHOR]

Elevated skeletal muscle diacylglycerols (DAGs) and ceramides can impair insulin signaling, and acylcarnitines (acylCNs) reflect impaired mitochondrial fatty acid oxidation, thus, the intramuscular lipid profile is indicative of insulin resistance. Acute (i.e., postprandial) hyperinsulinemia has been shown to elevate lipid concentrations in healthy muscle and is an independent risk factor for type 2 diabetes (T2D). However, it is unclear how the relationship between acute hyperinsulinemia and the muscle lipidome interacts across metabolic phenotypes, thus contributing to or exacerbating insulin resistance. We therefore investigated the impact of acute hyperinsulinemia on the skeletal muscle lipid profile to help characterize the physiological basis in which hyperinsulinemia elevates T2D risk. In a cross-sectional comparison, endurance athletes (n = 12), sedentary lean adults (n = 12), and individuals with obesity (n = 13) and T2D (n = 7) underwent a hyperinsulinemic-euglycemic clamp with muscle biopsies. Although there were no significant differences in total 1,2-DAG fluctuations, there was a 2% decrease in athletes versus a 53% increase in T2D during acute hyperinsulinemia (P = 0.087). Moreover, C18 1,2-DAG species increased during the clamp with T2D only, which negatively correlated with insulin sensitivity (P < 0.050). Basal muscle C18:0 total ceramides were elevated with T2D (P = 0.029), but not altered by clamp. Acylcarnitines were universally lowered during hyperinsulinemia, with more robust reductions of 80% in athletes compared with only 46% with T2D (albeit not statistically significant, main effect of group, P = 0.624). Similar fluctuations with acute hyperinsulinemia increasing 1,2 DAGs in insulin-resistant phenotypes and universally lowering acylcarnitines were observed in male mice. In conclusion, acute hyperinsulinemia elevates muscle 1,2-DAG levels with insulin-resistant phenotypes. This suggests a possible dysregulation of intramuscular lipid metabolism in the fed state in individuals with low insulin sensitivity, which may exacerbate insulin resistance. NEW & NOTEWORTHY: Postprandial hyperinsulinemia is a risk factor for type 2 diabetes and may increase muscle lipids. However, it is unclear how the relationship between acute hyperinsulinemia and the muscle lipidome interacts across metabolic phenotypes, thus contributing to insulin resistance. We observed that acute hyperinsulinemia elevates muscle 1,2-DAGs in insulin-resistant phenotypes, whereas ceramides were unaltered. Insulin-mediated acylcarnitine reductions are also hindered with high-fat feeding. The postprandial period may exacerbate insulin resistance in metabolically unhealthy phenotypes. [ABSTRACT FROM AUTHOR]

Acylcarnitines are important markers in metabolic studies of many diseases, including metabolic, cardiovascular, and neurological disorders. We reviewed analytical methods for analyzing acylcarnitines with respect to the available molecular structural information, the technical limitations of legacy methods, and the potential of new mass spectrometry-based techniques to provide new information on metabolite structure. We summarized the nomenclature of acylcarnitines based on historical common names and common abbreviations, and we propose the use of systematic abbreviations derived from the shorthand notation for lipid structures. The transition to systematic nomenclature will facilitate acylcarnitine annotation, reporting, and standardization in metabolomics. We have reviewed the metabolic origins of acylcarnitines important for the biological interpretation of human metabolomic profiles. We identified neglected isomers of acylcarnitines and summarized the metabolic pathways involved in the synthesis and degradation of acylcarnitines, including branched-chain lipids and amino acids. We reviewed the primary literature, mapped the metabolic transformations of acyl-CoAs to acylcarnitines, and created a freely available WikiPathway WP5423 to help researchers navigate the acylcarnitine field. The WikiPathway was curated, metabolites and metabolic reactions were annotated, and references were included. We also provide a table for conversion between common names and abbreviations and systematic abbreviations linked to the LIPID MAPS or Human Metabolome Database. [ABSTRACT FROM AUTHOR]

ABSTRACT Coral reefs are experiencing unprecedented loss in coral cover due to increased incidence of disease and bleaching events. Thus, understanding mechanisms of disease susceptibility and resilience, which vary by species, is important. In this regard, untargeted metabolomics serves as an important hypothesis-building tool enabling the delineation of molecular factors underlying disease susceptibility or resilience. In this study, we characterize metabolomes of four species of visually healthy stony corals, including Meandrina meandrites, Orbicella faveolata, Colpophyllia natans, and Montastraea cavernosa, collected at least a year before stony coral tissue loss disease reached the Dry Tortugas, Florida, and demonstrate that both symbiont and host-derived biochemical pathways vary by species. Metabolomes of Meandrina meandrites displayed minimal intraspecies variability and the highest biological activity against coral pathogens when compared to other species in this study. The application of advanced metabolite annotation methods enabled the delineation of several pathways underlying interspecies variability. Specifically, endosymbiont-derived vitamin E family compounds, betaine lipids, and host-derived acylcarnitines were among the top predictors of interspecies variability. Since several metabolite features that contributed to inter- and intraspecies variation are synthesized by the endosymbiotic Symbiodiniaceae, which could be a major source of these compounds in corals, our data will guide further investigations into these Symbiodiniaceae-derived pathways.IMPORTANCEPrevious research profiling gene expression, proteins, and metabolites produced during thermal stress have reported the importance of endosymbiont-derived pathways in coral bleaching resistance. However, our understanding of interspecies variation in these pathways among healthy corals and their role in diseases is limited. We surveyed the metabolomes of four species of healthy corals with differing susceptibilities to the devastating stony coral tissue loss disease and applied advanced annotation approaches in untargeted metabolomics to determine the interspecies variation in host and endosymbiont-derived pathways. Using this approach, we propose the survey of immune markers such as vitamin E family compounds, acylcarnitines, and other metabolites to infer their role in resilience to coral diseases. As time-resolved multi-omics datasets are generated for disease-impacted corals, our approach and findings will be valuable in providing insight into the mechanisms of disease resistance.

Background: Atrial fibrillation (AF) is the most common arrhythmia diagnosed at an older age. AF is associated with frailty, a condition possibly justifying the higher rate of complications and mortality in aged individuals. This study was aimed at describing the characteristics correlated to frailty in older AF subjects. Methods: After having excluded a

Background & Aims: In patients with cirrhosis, acute decompensation (AD) correlates with a hyperinflammatory state driven by mitochondrial dysfunction, which is a significant factor in the progression toward acute-on-chronic liver failure (ACLF). Elevated circulating levels of acylcarnitine, indicative of mitochondrial dysfunction, are predictors of mortality in ACLF patients. Our hypothesis posits that acylcarnitines not only act as biomarkers, but also actively exert detrimental effects on circulating immune cells. Methods: Plasma acylcarnitine levels were measured in 20 patients with AD cirrhosis and 10 healthy individuals. The effects of selected medium- and long-chain acylcarnitines on mitochondrial function were investigated in peripheral leucocytes from healthy donors by determining mitochondrial membrane potential (Δψm) and mitochondrial respiration using the JC-1 dye and Agilent Seahorse XF technology. Changes regarding mitochondrial ultrastructure and redox systems were assessed by transmission electron microscopy and gene and protein expression analysis. Results: Plasma levels of several acylcarnitine species were significantly elevated in patients with AD cirrhosis compared with healthy individuals, alongside increased levels of inflammatory mediators (cytokines and chemokines). Notably, the long-chain acylcarnitine palmitoylcarnitine (C16:0-carnitine, 1.51-fold higher, p = 0.0059) impaired Δψm and reduced the spare respiratory capacity of peripheral mononuclear leucocytes. Additionally, C16:0-carnitine induced mitochondrial oxidative stress, suppressed the expression of the antioxidant gene HMOX1, and increased CXCL8 expression and IL-8 release. Etomoxir, which blocks acylcarnitine entry into the mitochondria, reversed the suppression of HMOX1. Similarly, trimetazidine, a fatty acid beta-oxidation inhibitor, prevented C16:0-carnitine-induced CXCL8 expression. Importantly, oxidative stress and Δψm impairment caused by C16:0-carnitine were less severe in the presence of albumin, a standard therapy for AD cirrhosis. Conclusions: Our findings suggest that long-chain acylcarnitines induce mitochondrial injury in immune cells, thereby contributing to the development of immune dysfunction associated with cirrhosis. Impact and implications: Patients with acute decompensation of cirrhosis and acute-on-chronic liver failure (ACLF) display a systemic hyperinflammatory state and leukocyte mitochondrial dysfunction. We discovered that apart from being increased in the circulation of these patients, the long-chain palmitoylcarnitine is able to elicit cytokine secretion paired with mitochondrial dysfunction in leukocytes from healthy donors. In particular, we show that inhibiting the metabolism of palmitoylcarnitine could reverse these detrimental effects. Our findings underline the importance of immunometabolism as a treatment target in patients with acute decompensation of cirrhosis and ACLF.

Abstract Objective This study aimed to discuss the distinctive features of the intestinal microbiota in neonates with hyperbilirubinemia and to comprehensively analyse the composition of the intestinal microbiota as well as the levels of free amino acids and acylcarnitines in the peripheral blood of neonates experiencing hyperbilirubinemia. Results At the phylum level, Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Chloroflexi were the five predominant microbial groups identified in both the hyperbilirubinemia and control groups. Alpha diversity analysis, encompassing seven indices, showed no statistically significant differences between the two groups. However, Beta diversity analysis revealed a significant difference in intestinal microbiota structure between the groups. Linear discriminant analysis effect size (LEfSe) indicated a significant reduction in the abundance of Gammaproteobacteria and Enterobacteriaceae within the hyperbilirubinemia group compared to that in the control group. The heatmap revealed that the control group exhibited increased abundances of Escherichia and Bifidobacterium, while the hyperbilirubinemia group exhibited increased levels of Enterococcus and Streptococcus. Regarding blood amino acids and acylcarnitines, there were greater concentrations of citrulline (Cit), arginine (Arg), ornithine (Orn), and valine (Val) in the hyperbilirubinemia group than in the control group. The hyperbilirubinemia group also exhibited significant increases in medium-chain fatty acids (C6, C8), long-chain fatty acids (C18), and free carnitine (C0). Conclusion By comparing neonates with hyperbilirubinemia to those without, a significant disparity in the community structure of the intestinal microbiota was observed. The intestinal microbiota plays a crucial role in the bilirubin metabolism process. The intestinal microbiota of neonates with hyperbilirubinemia exhibited a certain degree of dysbiosis. The abundances of Bacteroides and Bifidobacterium were negatively correlated with the bilirubin concentration. Therefore, the fact that neonates with hyperbilirubinemia exhibit some variations in blood amino acid and acylcarnitine levels may provide, to a certain degree, a theoretical basis for clinical treatment and diagnosis.

ABSTRACT Recurrent C. difficile infection (rCDI) is an urgent public health threat, for which the last resort and lifesaving treatment is a fecal microbiota transplant (FMT). However, the exact mechanisms that mediate a successful FMT are not well-understood. Here, we use longitudinal stool samples collected from patients undergoing FMT to evaluate intra-individual changes in the microbiome, metabolome, and lipidome after successful FMTs relative to their baselines pre-FMT. We show changes in the abundance of many lipids, specifically a decrease in acylcarnitines post-FMT, and a shift from conjugated bile acids pre-FMT to deconjugated secondary bile acids post-FMT. These changes correlate with a decrease in Enterobacteriaceae, which encode carnitine metabolism genes, and an increase in Lachnospiraceae, which encode bile acid altering genes such as bile salt hydrolases (BSHs) and the bile acid-inducible (bai) operon, post-FMT. We also show changes in gut microbe-encoded amino acid biosynthesis genes, of which Enterobacteriaceae was the primary contributor to amino acids C. difficile is auxotrophic for. Liquid chromatography, ion mobility spectrometry, and mass spectrometry (LC-IMS-MS) revealed a shift from microbial conjugation of primary bile acids pre-FMT to secondary bile acids post-FMT. Here, we define the structural and functional changes associated with a successful FMT and generate hypotheses that require further experimental validation. This information is meant to help guide the development of new microbiota-focused therapeutics to treat rCDI.IMPORTANCERecurrent C. difficile infection is an urgent public health threat, for which the last resort and lifesaving treatment is a fecal microbiota transplant. However, the exact mechanisms that mediate a successful FMT are not well-understood. Here, we show changes in the abundance of many lipids, specifically acylcarnitines and bile acids, in response to FMT. These changes correlate with Enterobacteriaceae pre-FMT, which encodes carnitine metabolism genes, and Lachnospiraceae post-FMT, which encodes bile salt hydrolases and baiA genes. There was also a shift from microbial conjugation of primary bile acids pre-FMT to secondary bile acids post-FMT. Here, we define the structural and functional changes associated with a successful FMT, which we hope will help aid in the development of new microbiota-focused therapeutics to treat rCDI.

The occurrence of hyperuricemia (HUA; elevated serum uric acid) in athletes is relatively high despite that exercise can potentially reduce the risk of developing this condition. Although recent studies have shown the beneficial properties of DAG in improving overall metabolic profiles, a comprehensive understanding of the effect of DAG in modulating HUA in athletes is still lacking. In this study, we leveraged combinatorial lipidomics and metabolomics to investigate the effect of replacing TAG with DAG in the diet of athletes with HUA. A total of 1,074 lipids and metabolites from 94 classes were quantitated in serum from 33 athletes, who were categorized into responders and non-responders based on whether serum uric acid levels returned to healthy levels after the DAG diet intervention. Lipidomics and metabolomics analyses revealed lower levels of xanthine and uric acid in responders, accompanied by elevated plasmalogen phosphatidylcholines and diminished acylcarnitine levels. Our results highlighted the mechanisms behind how the DAG diet circumvented the risk and effects associated with high uric acid via lowered triglycerides at baseline influencing the absorption of DAG resulting in a decline in ROS and uric acid production, increased phospholipid levels associated with reduced p-Cresol metabolism potentially impacting on intestinal excretion of uric acid as well as improved ammonia recycling contributing to decreased serum uric acid levels in responders. These observed alterations might be suggestive that successful implementation of the DAG diet can potentially minimize the likelihood of a potentially vicious cycle occurring in high uric acid, elevated ROS, and impaired mitochondrial metabolism environment.

This article offers a personal account of a remarkable journey spanning over 30 years of applied mass spectrometry in a clinical setting. It begins with the author's inspiration from a clinician's story of rescuing a child from near death with a revolutionary therapeutic intervention. Motivated by this experience, the author delved into the field of chemistry and mass spectrometry to solve an analytical challenge. The breakthrough came with the development of the first front-line diagnostic test performed by MS/MS, which focused on analyzing acylcarnitines to detect and diagnose inherited disorders related to fatty acid and branched-chain amino acid catabolism. Building upon this success, the author expanded the application of the method to dried blood spots, incorporating additional analytical components such as essential amino acids. The result was a groundbreaking multiplex assay capable of screening newborns for more than 30 inherited metabolic conditions with just one test. This novel approach laid the foundation for a targeted metabolomics platform that facilitated the identification of new animal models of metabolic disease through screening the offspring of genetically modified adults. The development and utilization of MS/MS with UPLC has led to the creation of new assays for biomarkers of metabolic disease, benefiting both the diagnosis and therapeutic monitoring of these conditions. The article provides compelling examples from the author's laboratory, highlighting the value and vast applications of these methods in the field of metabolic disease research.

The Extended Screening for Inborn Errors of Metabolism is done for aminoacidopathies, fatty acid oxidation disorders and organic acid disorders. In a single dried blood spot, the tandem mass spectrometry is capable of measuring multiple analytes like amino acids, acylcarnitines, nucleosides, succinylacetone and lysophosphatidylcholines. This study was proposed to establish age specific reference internal for aminoacids and acylcartinitine in dried blood spot by tandem mass spectrometry. A total of 480 apparently healthy children were enrolled for the study and sub classified into four groups as follows: Group A: 0–1 month, Group B: 1 month–1 year, Group C: 1–5 year and Group D: 5–12 years each having 120 participants. Sample size were calculated as per CLSI approved guidelines. Tables 1 and 2 presents the age-specific percentile distribution of aminoacids and acylcarnitines established from healthy subjects as per rank-based method recommended by the IFCC and CLSI. Tables 3, 4 and 5 presents the cut-off values of primary and secondary marker/ratios for screening of aminoacidopathies, fatty acid oxidation disorders and organic acid disorders respectively. As a general principle, the interpretation of extended newborn screening results should be based on age specific cut-off established by the laboratory for primary analyte concentration and secondary analyte concentration/ ratios. This study was useful in establishing age specific cut-off values for various amino acids and acylcarnitines in South Indian population. Table 1 Age-specific percentile distribution of aminoacids Study groups Group A (μmol/L) Group B (μmol/L) Group C (μmol/L) Group D (μmol/L) Percentile 1 2.5 50 97.5 99 1 2.5 50 97.5 99 1 2.5 50 97.5 99 1 2.5 50 97.5 99 Glycine 44.00 50.00 361.85 745.00 840.00 76.00 81.00 351.41 705.00 820.00 88.00 92.00 383.00 620.00 785.00 109.00 115.00 397.74 600.00 790.00 Alanine 66.00 72.00 325.95 570.00 620.00 66.00 72.00 325.82 580.00 623.00 91.00 99.00 323.40 480.00 514.00 112.00 134.00 355.43 510.00 536.00 ASA 0.00 0.02 0.87 1.20 1.43 0.00 0.00 0.50 0.82 1.15 0.00 0.01 0.55 0.64 0.93 0.00 0.01 0.57 0.72 0.98 Leucine 24.00 33.52 120.84 270.00 300.00 23.00 33.78 113.42 264.00 300.00 44.00 52.01 110.43 223.00 250.00 42.00 52.76 118.91 224.00 250.00 Methionine 0.00 1.00 18.13 37.79 42.00 0.00 1.16 19.10 38.68 44.00 2.21 6.93 18.86 36.79 39.00 2.56 5.36 17.37 35.56 39.00 Ornithine 19.57 21.34 121.49 239.00 257.00 19.00 18.27 125.46 235.00 260.00 18.00 21.91 121.49 220.00 248.00 15.16 27.66 116.84 226.00 244.00 Phenylalanine 15.00 17.00 59.12 134.00 140.00 12.51 15.31 58.66 124.00 136.00 20.00 29.09 52.19 120.00 132.00 22.50 27.69 51.23 125.00 150.00 Proline 30.00 32.00 160.13 326.30 348.00 45.00 52.32 149.49 317.47 330.00 34.00 38.89 141.74 269.47 300.00 49.00 56.38 149.65 324.44 360.00 Tyrosine 15.34 16.38 116.28 274.00 300.00 17.00 20.59 115.67 260.00 290.00 16.50 17.12 94.94 180.00 220.00 24.00 29.14 91.50 190.00 220.00 Valine 29.00 31.86 111.86 265.03 285.00 28.00 32.65 102.24 252.76 260.00 41.00 58.80 113.00 250.80 264.00 54.00 63.99 130.96 242.74 260.00 Arginine 1.12 1.76 24.39 57.35 65.00 1.23 1.84 27.41 60.00 68.00 1.56 2.16 29.20 72.00 77.00 1.68 2.24 31.12 78.00 82.00 Citrulline 4.00 4.62 18.11 48.67 51.00 3.50 3.79 19.57 47.11 50.00 5.80 6.54 17.37 33.92 37.00 8.80 9.35 18.37 35.45 38.00 Table 2 Age-specific percentile distribution of acylcarnitines Study groups Group A (μmol/L) Group B (μmol/L) Group C (μmol/L) Group D (μmol/L) Percentile 1 2.5 50 97.5 99 1 2.5 50 97.5 99 1 2.5 50 97.5 99 1 2.5 50 97.5 99 Free carnitine (C0) 6.00 7.12 68.33 113.26 119.23 7.20 9.54 40.43 90.69 96.80 7.10 8.00 37.40 84.10 86.70 8.78 10.43 44.13 79.00 87.90 Acetylcarnitine (C2) 1.80 2.00 26.24 60.23 62.00 2.10 2.30 25.25 58.76 60.58 2.10 2.50 24.93 55.72 57.68 2.60 3.00 24.79 54.00 56.70 Propionylcarnitine (C3) 0.01 0.02 2.65 6.81 7.00 0.12 0.17 2.38 6.70 6.89 0.38 0.57 2.35 6.65 6.70 0.39 0.50 2.38 6.50 6.70 3-OH-butrylcarnitine (C3DC/C4OH) 0.00 0.01 0.23 0.68 0.69 0.01 0.02 0.22 0.65 0.67 0.02 0.04 0.21 0.47 0.50 0.01 0.04 0.21 0.48 0.50 Butrylcarnitine (C4) 0.06 0.09 0.59 1.20 1.30 0.06 0.07 0.52 1.20 1.27 0.06 0.09 0.51 1.00 1.16 0.08 0.10 0.50 1.00 1.13 3-OH-isovalerylcarnitine (C4DC/C5-OH) 0.02 0.04 0.38 0.82 0.87 0.04 0.06 0.37 0.79 0.81 0.07 0.09 0.34 0.69 0.70 0.07 0.08 0.33 0.67 0.68 Isovalerl/2-methylbutrylcarnitine (C5) 0.02 0.02 0.28 0.62 0.63 0.02 0.03 0.27 0.63 0.65 0.02 0.03 0.27 0.60 0.61 0.02 0.03 0.26 0.61 0.62 Tiglycarnitine (C5:1) 0.00 0.00 0.03 0.09 0.09 0.00 0.00 0.02 0.07 0.08 0.00 0.00 0.02 0.06 0.07 0.00 0.00 0.02 0.06 0.07 Glutarylcarnitine (C5DC/C6OH) 0.00 0.02 0.14 0.35 0.37 0.00 0.01 0.15 0.37 0.37 0.01 0.04 0.18 0.38 0.40 0.01 0.04 0.19 0.41 0.42 Hexanoylcarnitine (C6) 0.00 0.02 0.13 0.30 0.31 0.00 0.02 0.14 0.29 0.30 0.00 0.02 0.11 0.23 0.25 0.00 0.02 0.12 0.25 0.26 Adipylcarnitine (C6DC) 0.00 0.02 0.27 0.58 0.60 0.00 0.03 0.27 0.60 0.61 0.00 0.03 0.16 0.34 0.35 0.00 0.02 0.16 0.36 0.37 Octanoylcarnitine (C8) 0.00 0.00 0.15 0.34 0.35 0.00 0.00 0.16 0.34 0.35 0.00 0.01 0.11 0.25 0.26 0.00 0.01 0.12 0.25 0.26 Octenoylcarnitine (C8:1) 0.00 0.00 0.01 0.30 0.32 0.00 0.00 0.02 0.31 0.32 0.00 0.01 0.01 0.31 0.32 0.00 0.01 0.01 0.31 0.32 Decanoylcarnitine (C10) 0.00 0.02 0.20 0.44 0.45 0.00 0.02 0.20 0.41 0.42 0.00 0.03 0.21 0.53 0.54 0.00 0.03 0.22 0.54 0.55 Decenoylcarnitine (C10:1) 0.00 0.01 0.11 0.24 0.25 0.00 0.02 0.10 0.23 0.24 0.00 0.01 0.14 0.30 0.32 0.00 0.02 0.16 0.33 0.34 Dodecanoylcarnitine (C10:2) 0.00 0.00 0.02 0.06 0.07 0.00 0.00 0.02 0.06 0.07 0.00 0.00 0.02 0.06 0.07 0.00 0.00 0.02 0.06 0.07 Dodecanoylcarnitine (C12) 0.00 0.01 0.17 0.41 0.42 0.00 0.02 0.16 0.41 0.42 0.00 0.02 0.14 0.41 0.42 0.00 0.01 0.14 0.40 0.41 Docecenoylcarnitine (C12:1) 1.00 0.01 0.03 0.38 0.39 0.00 0.01 0.02 0.36 0.37 0.00 0.00 0.02 0.36 0.37 0.00 0.00 0.02 0.36 0.37 Tetradecanoylcarnitine (C14) 0.01 0.04 0.18 0.40 0.41 0.02 0.04 0.18 0.38 0.40 0.02 0.04 0.16 0.32 0.33 0.01 0.03 0.16 0.31 0.32 Tetradecenoylcarnitine (C14:1) 0.00 0.01 0.13 0.28 0.29 0.00 0.01 0.14 0.27 0.29 0.00 0.01 0.12 0.24 0.25 0.00 0.01 0.11 0.23 0.25 Tetradecadienoylcarnitine (C14:2) 0.00 0.00 0.01 0.03 0.04 0.00 0.00 0.01 0.03 0.04 0.00 0.00 0.01 0.03 0.04 0.00 0.01 0.01 0.03 0.04 3-OH-tetradecenoylcarnitine (C14-OH) 0.00 0.00 0.03 0.07 0.08 0.00 0.00 0.03 0.07 0.08 0.00 0.00 0.02 0.07 0.07 0.00 0.00 0.02 0.07 0.07 Hexadecanoylcarnitine (C16) 0.20 0.30 4.17 7.44 7.50 0.30 0.50 3.15 7.44 7.50 0.65 0.71 3.90 6.50 6.50 0.70 0.71 3.90 6.50 6.50 Hexadecenoylcarnitine (C16:1) 0.03 0.04 0.31 0.70 0.71 0.03 0.04 0.28 0.65 0.68 0.03 0.04 0.22 0.47 0.48 0.02 0.04 0.22 0.48 0.50 3-OH-hexadecanoylcarnitine (C16-OH) 0.00 0.00 0.03 0.09 0.10 0.00 0.00 0.03 0.08 0.09 0.00 0.00 0.03 0.07 0.08 0.00 0.00 0.03 0.08 0.09 3-Ohhexadecenoyl/heptadecanoylcarnitine (C16:1-OH/C17) 0.00 0.01 0.04 0.11 0.12 0.00 0.01 0.05 0.11 0.12 0.00 0.01 0.05 0.12 0.13 0.00 0.01 0.05 0.12 0.13 Stearoylcarnitine (C18) 0.09 0.09 1.10 2.20 2.30 0.09 0.09 1.10 2.20 2.30 0.23 0.24 0.90 1.70 1.80 0.23 0.24 0.89 1.70 1.80 Oleylcarnitine (C18:1) 0.11 0.12 1.70 3.00 3.04 0.12 0.13 1.51 3.00 3.10 0.32 0.34 1.13 2.30 2.40 0.31 0.33 1.24 2.40 2.50 3-OH-octadecanoylcarnitine (C18-OH) 0.00 0.00 0.01 0.08 0.09 0.00 0.00 0.00 0.08 0.08 0.00 0.00 0.00 0.07 0.07 0.00 0.00 0.00 0.07 0.08 Linoleylcarnitine (C18:2) 0.00 0.02 0.38 0.84 0.86 0.00 0.02 0.37 0.83 0.85 0.00 0.02 0.38 0.85 0.88 0.00 0.02 0.36 0.85 0.88 3-OH-oleylcarnitine (C18:1-OH) 0.00 0.01 0.09 0.17 0.18 0.00 0.01 0.09 0.17 0.18 0.00 0.01 0.07 0.15 0.16 0.00 0.01 0.07 0.15 0.16 Adenosine (ADO) 0.00 0.01 1.40 3.19 3.20 0.00 0.00 1.54 3.19 3.20 0.00 0.01 1.52 3.10 3.12 0.00 0.01 1.49 3.11 3.12 2-Deoxyadenosine (dADO) 0.00 0.01 0.09 0.14 0.15 0.00 0.01 0.06 0.13 0.14 0.00 0.01 0.05 0.11 0.12 0.00 0.01 0.06 0.11 0.12 Table 3 The cut-off values of primary and secondary marker/ratios for screening of aminoacidopathies RUSP core condition (Aminoacidopathies) Primary marker secondary marker Cut-offs Group A (μmol/L) Cut-offs Group B (μmol/L) Cut-offs Group C (μmol/L) Cut-offs Group D (μmol/L) Phenylketonuria (PKU) Phe 140 136 132 150 Phe/Tyr 1.5 1.4 1.4 1.6 Phe/(Leu + Ile) 1.2 1.2 1.2 1.3 Maple syrup urine disease (MSUD) (Leu + Ile) 300 300 250 250 Val 285 260 264 260 (Leu + Ile)/Phe 6.1 6.2 4.8 4.9 (Leu + Ile)/Ala 0.92 0.92 0.77 0.70 Homocystinuria (CBS) Met 42 44 39 39 Met/(Leu + Ile) 0.35 0.39 0.35 0.33 Citullinemia type I (CIT I) Cit 51 50 37 38 Cit/Arg 2.1 1.8 1.3 1.2 Arginosuccinic acidemia (ASA) ASA 1.43 1.15 0.93 0.98 Cit 51 50 37 38 Cit/Phe 0.86 0.85 0.70 0.74 Tyrosinemia type I (TYR) Tyr 300 290 220 220 Tyr/Phe 5.07 4.94 4.21 4.29 Argininemia (ARG) Arg 65 68 77 82 Arg/Orn 0.53 0.54 0.63 0.70 Table 4 The cut-off values of primary and secondary marker/ ratios for screening of fatty acid oxidation disorders RUSP core condition (fatty acid oxidation disorders) Primary marker secondary marker Cut-offs Group A (μmol/L) Cut-offs Group B (μmol/L) Cut-offs Group C (μmol/L) Cut-offs Group D (μmol/L) Medium-chain acyl-CoA dehydrogenase deficiency (MCAD) C8 0.35 0.35 0.26 0.26 C6 0.31 0.30 0.25 0.26 C10:1 0.25 0.24 0.32 0.34 C8/C2 0.01 0.01 0.01 0.01 Very long chain acyl-CoA dehydrogenase deficiency (VLCAD) C14:1 0.29 0.29 0.25 0.25 C14 0.41 0.40 0.33 0.32 C14:2 0.04 0.04 0.04 0.04 C12 0.42 0.42 0.42 0.41 C14:1/C2 0.01 0.01 0.01 0.01 Long chain l-3hydroxy acyl CoA dehydrogenase deficiency (LCHAD) C18-OH 0.09 0.08 0.07 0.08 C16-OH 0.10 0.09 0.08 0.09 C18:1-OH 0.18 0.18 0.16 0.16 C18-OH/C18 0.08 0.07 0.07 0.08 Carnitine uptake defect/carnitine transport defect (CUD) C0 (low) 6.00 7.20 7.10 8.78 C2 (low) 1.80 2.10 2.10 2.60 C3 (low) 0.12 0.12 0.38 0.39 C16 (low) 0.20 0.30 0.65 0.70 C18 (low) 0.09 0.09 0.23 0.23 (C0 + C2 + C3 + C16 + C18:1 + C18)/CIT 0.45 0.51 0.62 0.71 Trifunctional protein deficiency (TFP) C18-OH 0.09 0.08 0.07 0.08 C16-OH 0.10 0.09 0.08 0.09 C18:1-OH 0.18 0.18 0.16 0.16 C14-OH 0.08 0.08 0.07 0.07 C18-OH/C18 0.08 0.07 0.07 0.08 Table 5 The cut-off values of primary and secondary marker/ ratios for screening of organic acid disorders RUSP core condition (organic acid disorders) Primary marker secondary marker Cut-offs Group A (μmol/L) Cut-offs Group B (μmol/L) Cut-offs Group C (μmol/L) Cut-offs Group D (μmol/L) Propionic acidemia/methylmalonic acidemia (PROP/MUT) C3 7.00 6.89 6.70 6.70 C3/C2 0.27 0.27 0.27 0.27 C3/C16 1.68 2.19 1.72 1.72 C16:1OH/C17 0.12 0.12 0.13 0.13 Isovaleric acidemia (IVA) C5 0.63 0.65 0.61 0.61 C5/C0 0.01 0.01 0.01 0.01 C5/C2 0.02 0.02 0.02 0.02 Glutaric acidemia type I (GA I) C5-DC 0.37 0.37 0.40 0.42 C5-DC/C5-OH 0.97 1.00 1.17 1.27 C5-DC/C8 2.46 2.31 3.63 3.50 3-Methylcrotonyl-CoA carboxylase deficiency (3MCC) C5-OH 0.87 0.81 0.70 0.68 C5-OH/C8 5.8 5.06 6.36 5.66 3-Hydroxy-3-methyglutaric aciduria (HMG) C5-OH 0.87 0.81 0.70 0.68 C6-DC 0.60 0.61 0.35 0.37 ß-Ketothiolase deficiency (BKT) C5:1 0.09 0.08 0.07 0.07 C5-OH 0.87 0.81 0.70 0.68 C4-OH 0.69 0.67 0.50 0.50 Malonic acidemia (MAL) C3-DC 0.69 0.67 0.50 0.50 C3-DC/C10 3.45 3.35 2.38 2.27 [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to determine if time-efficient, high-resistance inspiratory muscle strength training (IMST), comprising 30 inhalation-resisted breaths per day, improves cardiorespiratory fitness, exercise tolerance, physical function, and/or regional body composition in healthy midlife and older adults. Methods: We performed a double-blind, randomized, sham-controlled clinical trial (NCT03266510) testing 6 wk of IMST (30 breaths per day, 6 d·wk−1, 55%–75% maximal inspiratory pressure) versus low-resistance sham training (15% maximal inspiratory pressure) in healthy men and women 50–79 yr old. Subjects performed a graded treadmill exercise test to exhaustion, physical performance battery (e.g., handgrip strength, leg press), and body composition testing (dual x-ray absorptiometry) at baseline and after 6 wk of training. Results: Thirty-five participants (17 women, 18 men) completed high-resistance IMST (n = 17) or sham training (n = 18). Cardiorespiratory fitness (V̇O2peak) was unchanged, but exercise tolerance, measured as treadmill exercise time during a graded exercise treadmill test, increased with IMST (baseline, 539 ± 42 s; end intervention, 606 ± 42 s; P = 0.01) but not sham training (baseline, 562 ± 39 s; end intervention, 553 ± 38 s; P = 0.69). IMST increased peak RER (baseline, 1.09 ± 0.02; end intervention, 1.13 ± 0.02; P = 0.012), peak ventilatory efficiency (baseline, 25.2 ± 0.8; end intervention, 24.6 ± 0.8; P = 0.036), and improved submaximal exercise economy (baseline, 23.5 ± 1.1 mL·kg−1⋅min−1; end intervention, 22.1 ± 1.1 mL·kg−1⋅min−1; P < 0.001); none of these factors were altered by sham training (all P > 0.05). Changes in plasma acylcarnitines (targeted metabolomics analysis) were consistently positively correlated with changes in exercise tolerance after IMST but not sham training. IMST was associated with regional increases in thorax lean mass (+4.4%, P = 0.06) and reductions in trunk fat mass (−4.8%, P = 0.04); however, peripheral muscle strength, muscle power, dexterity, and mobility were unchanged. Conclusions: These data suggest that high-resistance IMST is an effective, time-efficient lifestyle intervention for improving exercise tolerance in healthy midlife and older adults. [ABSTRACT FROM AUTHOR]

Acylcarnitine and amino acid analyses of dried blood spot (DBS) samples using tandem mass spectrometry in newborn screening (NBS) programmes can generate false positive (FP) results. Therefore, implementation of second-tier tests (2TTs) using DBS samples has become increasingly important to avoid FPs. The most widely used 2TT metabolites include methylmalonic acid, 3-hydroxypropionic acid, methylcitric acid, and homocysteine. We simultaneously measured 46 underivatised metabolites, including organic acids, acylglycine and acylcarnitine isomers, homocysteine, and orotic acid, in DBS samples using tandem mass spectrometry. To validate this method, we analysed samples from 147 healthy newborns, 160 patients with genetic disorders diagnosed via NBS, 20 patients with acquired vitamin B12 deficiency, 10 newborns receiving antibiotic treatment, and nine external quality control samples. The validation study revealed that 31 metabolites showed good analytical performance. Furthermore, this method detected key metabolites for all diseases associated with increased levels of the following acylcarnitines: C3, C4, C5, C4DC/C5OH, and C5DC. The sensitivity of this method to detect all diseases was 100 %, and the specificity was 74–99 %, except for glutaric aciduria type 1. This method can also be used to diagnose mitochondrial fatty acid β-oxidation disorders (FAODs) and urea cycle defects (UCDs). We have described a 2TT panel of 31 metabolites in DBS samples based on an easy and rapid method without derivatisation. Its implementation allowed us to distinguish between different organic acidurias, some FAODs, and UCDs. This new strategy has increased the efficiency of our NBS programme by reducing FP and false negative results, second sample requests, and the time required for diagnosis. [ABSTRACT FROM AUTHOR]

Objective: Congenital hypothyroidism (CH) is an inborn thyroid hormone (TH) deficiency mostly caused by thyroidal (primary CH) or hypothalamic/pituitary (central CH) disturbances. Most CH newborn screening (NBS) programs are thyroid-stimulating-hormone (TSH) based, thereby only detecting primary CH. The Dutch NBS is based on measuring total thyroxine (T4) from dried blood spots, aiming to detect primary and central CH at the cost of more false-positive referrals (FPRs) (positive predictive value (PPV) of 21% in 2007–2017). An artificial PPV of 26% was yielded when using a machine learning-based model on the adjusted dataset described based on the Dutch CH NBS. Recently, amino acids (AAs) and acylcarnitines (ACs) have been shown to be associated with TH concentration. We therefore aimed to investigate whether AAs and ACs measured during NBS can contribute to better performance of the CH screening in the Netherlands by using a revised machine learning-based model. Methods: Dutch NBS data between 2007 and 2017 (CH screening results, AAs and ACs) from 1079 FPRs, 515 newborns with primary (431) and central CH (84) and data from 1842 healthy controls were used. A random forest model including these data was developed. Results: The random forest model with an artificial sensitivity of 100% yielded a PPV of 48% and AUROC of 0.99. Besides T4 and TSH, tyrosine, and succinylacetone were the main parameters contributing to the model’s performance. Conclusions: The PPV improved significantly (26–48%) by adding several AAs and ACs to our machine learning-based model, suggesting that adding these parameters benefits the current algorithm.

Background: Physiological changes of blood amino acids and acylcarnitines during healthy child development are poorly studied. The LIFE (Leipziger Forschungszentrum für Zivilisationserkrankungen) Child study offers a platform with a large cohort of healthy children to investigate these dynamics. We aimed to assess the intra-person variability of 28 blood metabolites and their associations with anthropometric parameters related to growth and excess body fat. Methods: Concentrations of 22 amino acids (AA), 5 acylcarnitines (AC) and free carnitine of 2213 children aged between 3 months and 19 years were analyzed using liquid chromatography/tandem mass spectrometry. Values were transformed into standard deviation scores (SDS) to account for sex- and age-related variations. The stability of metabolites was assessed through the coefficient of determination. Associations with parameters for body composition and insulin-like growth factor-I (IGF-I) SDS were determined by the Pearson correlation and linear regression. Results: Our research revealed substantial within-person variation in metabolite concentrations during childhood and adolescence. Most metabolites showed a positive correlation with body composition parameters, with a notable influence of sex, pubertal status and weight group. Glycine exhibited negative associations with parameters of body fat distribution, especially in normal weight girls, overweight/obese boys and during puberty. Conclusion: Blood AA and AC measurements may contribute to elucidating pathogenesis pathways of adiposity-related comorbidities, but the specific timings and conditions of development during childhood and adolescence need to be taken into consideration.

Metabolic syndrome (MetS) is a group of several metabolic conditions predisposing to chronic diseases. Individuals diagnosed with MetS are physiologically heterogeneous, with significant sex-specific differences. Therefore, we aimed to investigate the potential sex-specific serum modifications of amino acids and acylcarnitines (ACs) and their relationship with MetS in the Mexican population. This study included 602 participants from the Health Workers Cohort Study. Forty serum metabolites were analyzed using a targeted metabolomics approach. Multivariate regression models were used to test associations of clinical and biochemical parameters with metabolomic profiles. Our findings showed a serum amino acid signature (citrulline and glycine) and medium-chain ACs (AC14:1, AC10, and AC18:10H) associated with MetS. Glycine and AC10 were specific metabolites representative of discrimination according to sex-dependent MetS. In addition, we found that glycine and short-chain ACs (AC2, AC3, and AC8:1) are associated with age-dependent MetS. We also reported a significant correlation between body fat and metabolites associated with sex-age-dependent MetS. In conclusion, the metabolic profile varies by MetS status, and these differences are sex-age-dependent in the Mexican population.

Abstract Aims Heart failure in adults is characterized by reduction of long‐chain fatty acid oxidation in favour of carbohydrate metabolism. This adaptive phenomenon becomes maladaptive because energy conversion decreases and lipid toxic derivatives known to impair cardiac function are accumulating. No data are available concerning metabolic modification in heart failure in children. Methods and results In order to evaluate the fatty acid oxidation in children suffering from heart failure, acylcarnitine profiles on dried blood spots were obtained from children under 16 years old with dilated cardiomyopathy and clinical heart failure (DCM‐HF) and control children. Nine children were included in the DCM‐HF group and eight in the control group. Acylcarnitine profiles revealed a significant 3.1‐fold increase of total acylcarnitines (sum of C3 to C18 acylcarnitine species) in DCM‐HF children compared with controls. This result persisted considering the sum of long‐chain acylcarnitines (sum of C14 to C18 species), medium‐chain acylcarnitines (sum of C8 to C12 species), and short‐chain acylcarnitines (sum of C3 to C6 species), respectively, 2.0‐, 2.6‐, and 1.9‐fold increase compared with the control group. A significant linear correlation was found between left ventricular dilatation or ejection fraction and acylcarnitines accumulation. Finally, acylcarnitine ratio C16OH/C16 and C18OH/C18 enhanced in the DCM‐HF group, suggesting a diminution of the long‐chain hydroxyl acyl‐CoA dehydrogenase activity. Conclusions Our results suggest down‐regulation of fatty acid oxidation in children with heart failure. Such lipidomic alteration could worsen heart function and may suggest considering a metabolic treatment of heart failure in children.

Abstract Background Due to the high risk of COVID-19 patients developing thrombosis in the circulating blood, atherosclerosis, and myocardial infarction, it is necessary to study the lipidome of erythrocytes. Specifically, we examined the pathogenic oxysterols and acylcarnitines in the erythrocyte homogenate of COVID-19 patients. These molecules can damage cells and contribute to the development of these diseases. Methods This study included 30 patients and 30 healthy volunteers. The erythrocyte homogenate extract was analyzed using linear ion trap mass spectrometry combined with high-performance liquid chromatography. The concentrations of oxysterols and acylcarnitines in erythrocyte homogenates of healthy individuals and COVID-19 patients were measured. Elevated levels of toxic biomarkers in red blood cells could initiate oxidative stress, leading to a process known as Eryptosis. Results In COVID-19 patients, the levels of five oxysterols and six acylcarnitines in erythrocyte homogenates were significantly higher than those in healthy individuals, with a p-value of less than 0.05. The mean total concentration of oxysterols in the red blood cells of COVID-19 patients was 23.36 ± 13.47 μg/mL, while in healthy volunteers, the mean total concentration was 4.92 ± 1.61 μg/mL. The 7-ketocholesterol and 4-cholestenone levels were five and ten times higher, respectively, in COVID-19 patients than in healthy individuals. The concentration of acylcarnitines in the red blood cell homogenate of COVID-19 patients was 2 to 4 times higher than that of healthy volunteers on average. This finding suggests that these toxic biomarkers may cause the red blood cell death seen in COVID-19 patients. Conclusions The abnormally high levels of oxysterols and acylcarnitines found in the erythrocytes of COVID-19 patients were associated with the severity of the cases, complications, and the substantial risk of thrombosis. The concentration of oxysterols in the erythrocyte homogenate could serve as a diagnostic biomarker for COVID-19 case severity. Graphical abstract

Summary: Background: Altered lipid metabolism is a hallmark of cancer development. However, the role of specific lipid metabolites in colorectal cancer development is uncertain. Methods: In a case–control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC), we examined associations between pre-diagnostic circulating concentrations of 97 lipid metabolites (acylcarnitines, glycerophospholipids and sphingolipids) and colorectal cancer risk. Circulating lipids were measured using targeted mass spectrometry in 1591 incident colorectal cancer cases (55% women) and 1591 matched controls. Multivariable conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between concentrations of individual lipid metabolites and metabolite patterns with colorectal cancer risk. Findings: Of the 97 assayed lipids, 24 were inversely associated (nominally p

Apolipoprotein E (APOE) genetic variants are most notably known for their divergent impact on the risk of developing Alzheimer’s disease. While APOE genotype has been consistently shown to modulate lipid metabolism in a variety of cellular contexts, the effect of APOE alleles on the lipidome in hepatocytes is unknown. In this study, we investigated the contribution of APOE alleles to lipidomic profiles of donor-derived primary human hepatocytes from 77 subjects. Lipidomic data obtained by liquid chromatography-mass spectrometry were analyzed across ε2/ε3, ε3/ε3, and ε3/ε4 genotypes to reveal how APOE modulates lipid relative levels over age and between groups. Hepatic APOE concentration, measured by ELISA, was assessed for correlation with lipid abundance in subjects grouped as per APOE genotype and sex. APOE genotype-specific differential lipidomic signatures associated with age for multiple lipid classes but did not differ between sexes. Compared to ε2/ε3, ε3/ε4 hepatocytes had higher abundance of acylcarnitines (AC) and acylphosphatidylglycerol (AcylPG) as a class, as well as higher medium and long-chain ACs, AcylPG, phosphatidylglycerol (PG), bis(monoacylglycerol)phosphate (BMP), monoacylglycerol (MG) and diacylglycerol (DG) species. The ε3/ε4 hepatocytes also exhibited a higher abundance of medium and long-chain ACs compared to the ε3/ε3 hepatocytes. Only in the ε3/ε4 hepatocytes, APOE concentration was lower and showed a negative correlation with BMP levels, specifically in females. APOE genotype dictates a differential lipidome in primary human hepatocytes. The lipids involved suggest mitochondrial dysfunction with accompanying alterations in neutral lipid storage, reflective of a general disturbance of free fatty acid metabolism in human hepatocytes with the ε4 allele.

Data on the prevalence of most inborn errors of metabolism are still unavailable in Kazakhstan. The study aims to perform selective screening for hereditary metabolic diseases among patients aged from 1 day to 18 years in western Kazakhstan using the LC-MS/MS method, with establishing the reference values for the content of amino acids, acylcarnitines, and succinylacetone in blood samples of healthy children. Tasks: 1. To assess the burden of metabolic disorders detected by LC-MS/MS in western Kazakhstan by examination of children at clinical risk in pediatric clinics throughout the region; https://www. frontiersin.org/register?returnUrl=https://loop.frontiersin.org 2. To set the reference values of metabolites in the child population; 3. To analyze the age distribution, prevalence, and age of onset for each identified IEM, further comparing the obtained findings with those from previously published reports in other populations. Methods: To set the reference values of 51 metabolites in the child population, 750 healthy children will be included. The selective screening will be performed among 1,500 patients aged 1 day to 18 years with suspected hereditary metabolic disorders. Anticipated results: The results of selective screening will be interpreted by comparison with the reference values established. Diagnosis will be based on clinical signs, blood levels of amino acids, acylcarnitines, succinylacetone, and urine levels of organic acids and tests for gene mutations. An assessment of 37 inborn errors of metabolism frequencies in high-risk children will be performed. The research will further develop the national as selective as expanded newborn screening programs. The study was registered in clinicaltrials. gov (https://www.clinicaltrials.gov/study/NCT05910151) on 16 June 2023. [ABSTRACT FROM AUTHOR]

Background: Major depression is associated with changes in plasma L-carnitine and acetyl-L-carnitine. But its association with acylcarnitines remains unclear. The aim of this study was to assess metabolomic profiles of 38 acylcarnitines in patients with major depression before and after treatment compared to healthy controls (HCs). Methods: Metabolomic profiles of 38 plasma short-, medium-, and long-chain acylcarnitines were performed by liquid chromatography-mass spectrometry in 893 HCs from the VARIETE cohort and 460 depressed patients from the METADAP cohort before and after 6 months of antidepressant treatment. Results: As compared to HCs, depressed patients had lower levels of medium- and long-chain acylcarnitines. After 6 months of treatment, increased levels of medium- and long-chain acyl-carnitines were observed that no longer differed from those of controls. Accordingly, several medium- and long-chain acylcarnitines were negatively correlated with depression severity. Conclusions: These medium- and long-chain acylcarnitine dysregulations argue for mitochondrial dysfunction through fatty acid β -oxidation impairment during major depression. [ABSTRACT FROM AUTHOR]

Background: Acylcarnitine is one of the crucial markers of fatty acid metabolism, and examination of their level in infants can reveal several Inherited Metabolic Disorders (IDM) or Inborn errors of Metabolism (IEM). Because of the great importance of hereditary, metabolic, and other inherited disorders early diagnosis before the appearance of clinical symptoms, this study was carried out to establish a reference range for carnitine analytes and to identify acylcarnitine profiles in normal weight neonatal dried blood spots (DBS) specimens. Methods: By using liquid chromatography tandem mass spectrometry (LC-MS/MS) for neonatal screening and eventually the examination and analysis of LC-MS/MS results, 34 acylcarnitine derivatives were identified. Results: The normal range for acylcarnitine analytes with carbon numbers ranging from zero to 18, both main and the branched ones, were ultimately measured. Afterward, they were compared with the results of some other diagnostic laboratories to be verified. Conclusion: This study differed from the other findings, which could be due to diversity in population and work methods. However, the reference range of most acylcarnitine derivatives in Tehran closely aligned with this study's findings. [ABSTRACT FROM AUTHOR]

Carnitine palmitoyltransferase II (CPT II) deficiency is an autosomal recessive disorder of long-chain fatty acid oxidation. Three clinical phenotypes, lethal neonatal form, severe infantile hepatocardiomuscular form, and myopathic form, have been described in CPT II deficiency. The myopathic form is usually mild and can manifest from infancy to adulthood, characterised by recurrent rhabdomyolysis episodes. The study aimed to investigate the clinical features, biochemical, histopathological, and genetic findings of 13 patients diagnosed with the myopathic form of CPT II deficiency at Ege University Hospital. A retrospective study was conducted with 13 patients with the myopathic form of CPT II deficiency. Our study considered demographic data, triggers of recurrent rhabdomyolysis attacks, biochemical metabolic screening, and molecular analysis. Ten patients were examined for rhabdomyolysis of unknown causes. Two patients were diagnosed during family screening, and one was diagnosed during investigations due to increased liver function tests. Acylcarnitine profiles were normal in five patients during rhabdomyolysis. Genetic studies have identified a c.338C>T (p.Ser113Leu) variant homozygous in 10 patients. One patient showed a novel frameshift variant compound heterozygous with c.338C>T (p.Ser113Leu). Plasma acylcarnitine analysis should be preferred as it is superior to DBS acylcarnitine analysis in diagnosing CPT II deficiency. Even if plasma acylcarnitine analysis is impossible, CPT2 gene analysis should be performed. Our study emphasizes that CPT II deficiency should be considered in the differential diagnosis of recurrent rhabdomyolysis, even if typical acylcarnitine elevation does not accompany it. [ABSTRACT FROM AUTHOR]

INTRODUCTION: A hallmark of Alzheimer's disease (AD) is the aggregation of proteins (amyloid beta [A] and hyperphosphorylated tau [T]) in the brain, making cerebrospinal fluid (CSF) proteins of particular interest. METHODS: We conducted a CSF proteome‐wide analysis among participants of varying AT pathology (n = 137 participants; 915 proteins) with nine CSF biomarkers of neurodegeneration and neuroinflammation. RESULTS: We identified 61 proteins significantly associated with the AT category (P < 5.46 × 10−5) and 636 significant protein‐biomarker associations (P < 6.07 × 10−6). Proteins from glucose and carbon metabolism pathways were enriched among amyloid‐ and tau‐associated proteins, including malate dehydrogenase and aldolase A, whose associations with tau were replicated in an independent cohort (n = 717). CSF metabolomics identified and replicated an association of succinylcarnitine with phosphorylated tau and other biomarkers. DISCUSSION: These results implicate glucose and carbon metabolic dysregulation and increased CSF succinylcarnitine levels with amyloid and tau pathology in AD. Highlights: Cerebrospinal fluid (CSF) proteome enriched for extracellular, neuronal, immune, and protein processing.Glucose/carbon metabolic pathways enriched among amyloid/tau‐associated proteins.Key glucose/carbon metabolism protein associations independently replicated.CSF proteome outperformed other omics data in predicting amyloid/tau positivity.CSF metabolomics identified and replicated a succinylcarnitine–phosphorylated tau association. [ABSTRACT FROM AUTHOR]

This article discusses the role of long-chain acylcarnitines (LCACs) in cardiac pathophysiology. Metabolomics studies have identified associations between LCACs and cardiovascular diseases such as heart failure and cardiac arrhythmias. The article focuses on the effects of LCACs on the ryanodine receptor (RyR2), a calcium release channel in cardiomyocytes. The study found that LCACs promote spontaneous calcium release and intracellular calcium accumulation, potentially through increased cytosolic calcium levels. The article also highlights the importance of considering methodological limitations and membrane perturbation effects when studying LCACs. The findings have implications for future research on LCACs and their potential as therapeutic targets for cardiovascular diseases. [Extracted from the article]

Background: Atrial fibrillation (AF) is associated with chronic inflammation, a hallmark of ageing process. The aim of this study was to determine interleukin-6 (IL-6)-associated variables, also exploring acylcarnitines, expression of mitochondrial abnormalities. Methods: We evaluated 22 controls and 50 patients with persistent AF. IL-6 and acylcarnitines were measured with ELISA kits and mass spectrometry techniques. Results: IL-6 concentration (mean: 3.9 ± 3.1 pg/mL) was lower in controls and increased in AF patients, especially with heart failure. The CHA2DS2-VASc, the MMSE and the SPPB scores were 3.8 ± 1.6, 28 ± 2 and 9.4 ± 2.1. Thirteen acylcanitines correlated with IL-6. At multivariable analysis, IL-6 was directly associated with C4-OH—a short-chain acylcarnitine, fibrinogen and alanine aminotransferase values, and with hyperuricemia. An inverse association existed with calcium concentration and SPPB score. Conclusions: In older AF patients, IL-6 correlated with acylcarnitines and lower physical performance. Alterations in energy production, reduced physical function and inflammation could contribute to frailty development. [ABSTRACT FROM AUTHOR]

Breast cancer brain metastasis (BCBM) has an incidence of 10–30%. It is incurable and the biological mechanisms that promote its progression remain largely undefined. Consequently, to gain insights into BCBM processes, we have developed a spontaneous mouse model of BCBM and in this study found a 20% penetrance of macro-metastatic brain lesion formation. Considering that lipid metabolism is indispensable to metastatic progression, our goal was the mapping of lipid distributions throughout the metastatic regions of the brain. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) of lipids revealed that, relative to surrounding brain tissue, seven long-chain (13–21 carbons long) fatty acylcarnitines, as well as two phosphatidylcholines, two phosphatidylinositols two diacylglycerols, a long-chain phosphatidylethanolamine, and a long-chain sphingomyelin were highly concentrated in the metastatic brain lesion In broad terms, lipids known to be enriched in brain tissues, such as very long-chain (≥ 22 carbons in length) polyunsaturated fatty acid of phosphatidylcholines, phosphatidylethanolamine, sphingomyelins, sulfatides, phosphatidylinositol phosphates, and galactosylceramides, were not found or only found in trace amounts in the metastatic lesion and instead consistently detected in surrounding brain tissues. The data, from this mouse model, highlights an accumulation of fatty acylcarnitines as possible biological makers of a chaotic inefficient vasculature within the metastasis, resulting in relatively inadequate blood flow and disruption of fatty acid β-oxidation due to ischemia/hypoxia. [ABSTRACT FROM AUTHOR]

Previous research suggests potential mitochondrial dysfunction and changes in fatty acid metabolism in a subgroup of individuals with autism spectrum disorder (ASD), indicated by higher lactate, pyruvate levels, and mitochondrial disorder prevalence. This study aimed to further investigate potential mitochondrial dysfunction in ASD by assessing blood metabolite levels linked to mitochondrial metabolism. Blood levels of creatine kinase (CK), alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate, pyruvate, free and total carnitine, as well as acylcarnitines were obtained in 73 adults with ASD (47 males, 26 females) and compared with those of 71 neurotypical controls (NTC) (44 males, 27 females). Correlations between blood parameters and psychometric ASD symptom scores were also explored. Lower CK (pcorr = 0.045) levels were found exclusively in males with ASD compared to NTC, with no such variation in females. ALT and AST levels did not differ significantly between both groups. After correction for antipsychotic and antidepressant medication, CK remained significant. ASD participants had lower serum lactate levels (pcorr = 0.036) compared to NTC, but pyruvate and carnitine concentrations showed no significant difference. ASD subjects had significantly increased levels of certain acylcarnitines, with a decrease in tetradecadienoyl‐carnitine (C14:2), and certain acylcarnitines correlated significantly with autistic symptom scores. We found reduced serum lactate levels in ASD, in contrast to previous studies suggesting elevated lactate or pyruvate. This difference may reflect the focus of our study on high‐functioning adults with ASD, who are likely to have fewer secondary genetic conditions associated with mitochondrial dysfunction. Our findings of significantly altered acylcarnitine levels in ASD support the hypothesis of altered fatty acid metabolism in a subset of ASD patients. Lay Summary: This study examined potential differences in energy metabolism in adults with autism spectrum disorder (ASD) and neurotypical controls (NTC), focusing on the function of mitochondria, the "powerhouses" of our cells. In contrast to previous research that reported elevated levels of lactate, an indicator of mitochondrial dysfunction, the study found lower levels of lactate in individuals with ASD compared to NTC, possibly due to a focus on adults with high‐functioning ASD. The study also reported alterations in fatty acid metabolism in ASD, as evidenced by specific changes in compounds called acylcarnitines, but more research is needed to understand the causes and implications of these changes. [ABSTRACT FROM AUTHOR]

BackgroundThe prevalence and mortality risk of depression in people with human immunodeficiency virus (HIV) infection receiving antiretroviral therapy (ART) is higher than in the general population, yet biomarkers for therapeutic targeting are unknown. In the current study, we aimed to identify plasma metabolites associated with depressive symptoms in people with HIV receiving ART.MethodsThis is a prospective study of ART-treated HIV-infected adults with or without depressive symptoms assessed using longitudinal Beck Depression Inventory scores. Plasma metabolite profiling was performed in 2 independent cohorts (total n = 99) using liquid and gas chromatography and tandem mass spectrometry.ResultsParticipants with depressive symptoms had lower neuroactive steroids (dehydroepiandrosterone sulfate [DHEA-S], androstenediols, and pregnenolone sulfate) compared with those without depressive symptoms. The cortisol/DHEA-S ratio, an indicator of hypothalamic-pituitary-adrenal axis imbalance, was associated with depressive symptoms (P < .01) because of low DHEA-S levels, whereas cortisol was similar between groups. The odds of having depressive symptoms increased with higher cortisol/DHEA-S ratios (adjusted odds ratio, 2.5 per 1-unit increase in z score; 95% confidence interval, 1.3-4.7), independent of age and sex. The kynurenine-to-tryptophan ratio showed no significant associations.ConclusionsThese findings suggest that altered neuroactive steroid metabolism may contribute to the pathophysiological mechanisms of depression in ART-treated HIV-infected adults, representing a potential biological pathway for therapeutic targeting.

Abstract Background Fatty acid oxidation (FAO) defects have been implicated in experimental models of acute lung injury and associated with poor outcomes in critical illness. In this study, we examined acylcarnitine profiles and 3-methylhistidine as markers of FAO defects and skeletal muscle catabolism, respectively, in patients with acute respiratory failure. We determined whether these metabolites were associated with host-response ARDS subphenotypes, inflammatory biomarkers, and clinical outcomes in acute respiratory failure. Methods In a nested case–control cohort study, we performed targeted analysis of serum metabolites of patients intubated for airway protection (airway controls), Class 1 (hypoinflammatory), and Class 2 (hyperinflammatory) ARDS patients (N = 50 per group) during early initiation of mechanical ventilation. Relative amounts were quantified by liquid chromatography high resolution mass spectrometry using isotope-labeled standards and analyzed with plasma biomarkers and clinical data. Results Of the acylcarnitines analyzed, octanoylcarnitine levels were twofold increased in Class 2 ARDS relative to Class 1 ARDS or airway controls (P = 0.0004 and

Data on the prevalence of most inborn errors of metabolism are still unavailable in Kazakhstan. The study aims to perform selective screening for hereditary metabolic diseases among patients aged from 1 day to 18 years in western Kazakhstan using the LC-MS/MS method, with establishing the reference values for the content of amino acids, acylcarnitines, and succinylacetone in blood samples of healthy children. Tasks: 1. To assess the burden of metabolic disorders detected by LC-MS/MS in western Kazakhstan by examination of children at clinical risk in pediatric clinics throughout the region; https://www.frontiersin.org/register?returnUrl=https://loop.frontiersin.org 2. To set the reference values of metabolites in the child population; 3. To analyze the age distribution, prevalence, and age of onset for each identified IEM, further comparing the obtained findings with those from previously published reports in other populations. Methods: To set the reference values of 51 metabolites in the child population, 750 healthy children will be included. The selective screening will be performed among 1,500 patients aged 1 day to 18 years with suspected hereditary metabolic disorders. Anticipated results: The results of selective screening will be interpreted by comparison with the reference values established. Diagnosis will be based on clinical signs, blood levels of amino acids, acylcarnitines, succinylacetone, and urine levels of organic acids and tests for gene mutations. An assessment of 37 inborn errors of metabolism frequencies in high-risk children will be performed. The research will further develop the national as selective as expanded newborn screening programs. The study was registered in clinicaltrials. gov (https://www.clinicaltrials.gov/study/NCT05910151) on 16 June 2023.

Metabolic reprogramming is an essential hallmark of cancer. Several studies have reported the dysregulation of acylcarnitine (ACar) metabolism in tumor cells, suggesting that changes in the blood ACar may be related to tumor growth. Accordingly, this study aimed to understand the alteration of serum ACar profiles in various solid tumors and explore the potential of differential serum ACars as diagnostic biomarkers. A series of 69 relatively abundant ACars were identified via untargeted analysis. Then, targeted metabolomics was used to describe the metabolic alterations in ACars between normal controls and patients with six types of solid tumors. The results suggested that changes in ACars correlated with their carbon chain length and saturation. The six tumor types had highly similar ACar metabolic profiles, indicating similar fatty acid oxidation (FAO) metabolic pathways. Moreover, the receiver operating curve analysis of differential ACars showed that 16 ACars (C8–C14) had high diagnostic capability towards the studied solid tumors. Specifically, the area under the curve of ACar 10:2 isomer2 and ACar 12:2 isomer2 was greater than 0.95. In conclusion, the marked decrease in the levels of medium- and long-chain ACars (C8–C18) in the six solid tumors suggests that they may have similar FAO-based metabolic pathways, which could afford a common target for cancer therapy. Additionally, 16 ACars (C8–C14) were identified as potential biomarkers for diagnosing six types of solid tumors.

For a long time, co-products of food processing have been used in animal feed, but far less in fish because of their assumed inability to cope with high-fiber diets. Research on feeding co-products to fish species that naturally consume fibrous diets are yet lacking. We here evaluated the impact of sugar beet pulp in the diet of tambaquí on nutrient metabolism, oxidative stress, inflammation, and intestinal histomorphometry. A total of 18 tambaquí fish (1616 ± 107 g; 2 years old) were randomly divided over 6 similar tanks with 3 fish per tank and randomly attributed to one of the six dietary treatments 0, 5, 10, 15, 20 and 25 % beet pulp addition and reared for 8 weeks. Water quality parameters (pH, NH3–N, EC, TDS, DO, and temperature) were assessed and recorded twice a week for each tank. A quadratic increase in intestinal villus length, paravilli and absorptive surface were observed with beet pulp addition. Ammonia and pH as quality indicators were significantly changing with beet pulp addition. A higher supply of glucogenic substrate to the citric acid cycle was noticed with beet pulp addition due to the positive correlation with blood propionylcarnitine: acetylcarnitine ratio while there was no effect on ketone body synthesis as measured through the 3-hydroxybutyrylcarnitine: acetylcarnitine ratio. No pronounced change of serum and whole fish histamine and lowered concentrations of serum malondialdehyde were observed with beet pulp addition. In conclusion, beet pulp induced a marked increase in intestinal villus architecture without signs of inflammation or oxidative stress. Large-scale studies need to clarify if these features lead to improved growth performance but this work opens options for further study. The non-linear pattern of some blood components with increasing beet pulp may call for future optimal dosing and feed form of beet pulp together.

Recent evidence shows that obesity correlates negatively with bone mass. However, traditional anthropometric measures such as body mass index could not discriminate visceral adipose tissue from subcutaneous adipose tissue. The visceral adiposity index (VAI) is a reliable sex-specified indicator of visceral adipose distribution and function. Thus, we aimed to identify metabolomic profiles associated with VAI and low bone mineral density (BMD). A total of 602 individuals from the Health Workers Cohort Study were included. Forty serum metabolites were measured using the targeted metabolomics approach, and multivariate regression models were used to test associations of metabolomic profiles with anthropometric, clinical, and biochemical parameters. The analysis showed a serum amino acid signature composed of glycine, leucine, arginine, valine, and acylcarnitines associated with high VAI and low BMD. In addition, we found a sex-dependent VAI in pathways related to primary bile acid biosynthesis, branched-chain amino acids, and the biosynthesis of pantothenate and coenzyme A (CoA). In conclusion, a metabolic profile differs by VAI and BMD status, and these changes are gender-dependent.

Aims: Heart failure in adults is characterized by reduction of long‐chain fatty acid oxidation in favour of carbohydrate metabolism. This adaptive phenomenon becomes maladaptive because energy conversion decreases and lipid toxic derivatives known to impair cardiac function are accumulating. No data are available concerning metabolic modification in heart failure in children. Methods and results: In order to evaluate the fatty acid oxidation in children suffering from heart failure, acylcarnitine profiles on dried blood spots were obtained from children under 16 years old with dilated cardiomyopathy and clinical heart failure (DCM‐HF) and control children. Nine children were included in the DCM‐HF group and eight in the control group. Acylcarnitine profiles revealed a significant 3.1‐fold increase of total acylcarnitines (sum of C3 to C18 acylcarnitine species) in DCM‐HF children compared with controls. This result persisted considering the sum of long‐chain acylcarnitines (sum of C14 to C18 species), medium‐chain acylcarnitines (sum of C8 to C12 species), and short‐chain acylcarnitines (sum of C3 to C6 species), respectively, 2.0‐, 2.6‐, and 1.9‐fold increase compared with the control group. A significant linear correlation was found between left ventricular dilatation or ejection fraction and acylcarnitines accumulation. Finally, acylcarnitine ratio C16OH/C16 and C18OH/C18 enhanced in the DCM‐HF group, suggesting a diminution of the long‐chain hydroxyl acyl‐CoA dehydrogenase activity. Conclusions: Our results suggest down‐regulation of fatty acid oxidation in children with heart failure. Such lipidomic alteration could worsen heart function and may suggest considering a metabolic treatment of heart failure in children. [ABSTRACT FROM AUTHOR]

Analysis of the acylcarnitines' (ACs) is the mainstay for screening for fatty acid oxidation disorders (FAOD). Data about the ACs profile in the dried blood spot samples of healthy newborns in Serbia are not at disposal. Therefore, we determined the ACs levels and established the cut-offs. Between August 2018 and August 2019 a total of 1771 samples had been analysed. Cut-offs, established using a non-parametric approach, were verified in comparison with the worldwide target ranges and the data for several Caucasian populations. The majority of ACs had comparable distribution in Serbian and the worldwide population. In case of discrepancy, the individual alterations had a frequency of less than 10%. Seventeen out of 25 established cutoffs were in the worldwide target range. Reliability of the cut-offs positioning out of the target ranges is not jeopardized, since alterations are negligible or similar findings were reported for other Caucasian populations. The established and verified set of cut-offs can be used in the future screening for carnitine uptake/transport defect, medium-chain acyl-CoA dehydrogenase deficiency, very long-chain acyl-CoA dehydrogenase deficiency, long-chain L-3 hydroxyacyl-CoA dehydrogenase deficiency, trifunctional protein deficiency, carnitine palmitoyltransferase deficiency Ia and II, as well as carnitine:acylcarnitine translocase deficiency. [ABSTRACT FROM AUTHOR]

Background: Due to the high risk of COVID-19 patients developing thrombosis in the circulating blood, atherosclerosis, and myocardial infarction, it is necessary to study the lipidome of erythrocytes. Specifically, we examined the pathogenic oxysterols and acylcarnitines in the erythrocyte homogenate of COVID-19 patients. These molecules can damage cells and contribute to the development of these diseases. Methods: This study included 30 patients and 30 healthy volunteers. The erythrocyte homogenate extract was analyzed using linear ion trap mass spectrometry combined with high-performance liquid chromatography. The concentrations of oxysterols and acylcarnitines in erythrocyte homogenates of healthy individuals and COVID-19 patients were measured. Elevated levels of toxic biomarkers in red blood cells could initiate oxidative stress, leading to a process known as Eryptosis. Results: In COVID-19 patients, the levels of five oxysterols and six acylcarnitines in erythrocyte homogenates were significantly higher than those in healthy individuals, with a p-value of less than 0.05. The mean total concentration of oxysterols in the red blood cells of COVID-19 patients was 23.36 ± 13.47 μg/mL, while in healthy volunteers, the mean total concentration was 4.92 ± 1.61 μg/mL. The 7-ketocholesterol and 4-cholestenone levels were five and ten times higher, respectively, in COVID-19 patients than in healthy individuals. The concentration of acylcarnitines in the red blood cell homogenate of COVID-19 patients was 2 to 4 times higher than that of healthy volunteers on average. This finding suggests that these toxic biomarkers may cause the red blood cell death seen in COVID-19 patients. Conclusions: The abnormally high levels of oxysterols and acylcarnitines found in the erythrocytes of COVID-19 patients were associated with the severity of the cases, complications, and the substantial risk of thrombosis. The concentration of oxysterols in the erythrocyte homogenate could serve as a diagnostic biomarker for COVID-19 case severity. [ABSTRACT FROM AUTHOR]

Patients with non-alcoholic steatohepatitis (NASH) show significantly faster progress in the stages of fibrosis compared to those with non-alcoholic fatty liver (NAFL) disease. The non-invasive diagnosis of NASH remains an unmet clinical need. Preliminary data have shown that sphingolipids, especially ceramides, fatty acids, and other lipid classes may be related to the presence of NASH and the histological activity of the disease. The aim of our study was to assess the association of certain plasma lipid classes, such as fatty acids, acylcarnitines, and ceramides, with the histopathological findings in patients with NASH. The study included three groups: patients with NASH (N = 12), NAFL (N = 10), and healthy [non non-alcoholic fatty liver disease (NAFLD)] controls (N = 15). Plasma samples were collected after 12 h of fasting, and targeted analyses for fatty acids, acylcarnitines, and ceramides were performed. Baseline clinical and demographic characteristics were collected. There was no significant difference in baseline characteristics across the three groups or between NAFL and NASH patients. Patients with NASH had increased levels of several fatty acids, including, among others, fatty acid (FA) 14:0, FA 15:0, FA 18:0, FA 18:3n3, as well as Cer(d18:1/16:0), compared to NAFL patients and healthy controls. No significant difference was found between NAFL patients and healthy controls. In conclusion, patients with NASH exhibited a distinctive plasma lipid profile that can differentiate them from NAFL patients and non-NAFLD populations. More data from larger cohorts are needed to validate these findings and examine possible implications for diagnostic and management strategies of the disease. [ABSTRACT FROM AUTHOR]

Simple Summary: Equids kept at pasture are at risk of being intoxicated by ingesting sycamore maple seeds or seedlings, which contain the two non-proteinogenic amino acids hypoglycin A and methylenecyclopropylglycine. These amino acids are converted into effective toxins by metabolic processes, inducing severe damage to oxidative muscles. Toxic metabolites are known to disrupt the cellular use of important energy sources such as short- and medium-chain fatty acids or branched-chain amino acids. The comparative examination of different tissues from five horses that died from this environmental intoxication named atypical myopathy revealed that the highest concentration of active toxins was found in muscles. In all the tissues analyzed, there was still unmetabolized hypoglycin A, which suggests that inhibiting the conversion of protoxins into toxic metabolites would be a possible therapeutic approach. Equine atypical myopathy is caused by hypoglycin A (HGA) and methylenecyclopropylglycine (MCPrG), the known protoxins of sycamore maple (Acer pseudoplatanus). Various tissues from five atypical myopathy cases were analyzed but only HGA was found. Whether deamination of MCPrG has already occurred in the intestine as the first stage of metabolization has not been investigated. Activation of the protoxins to methylenecyclopropylacetyl (MCPA)-CoA and methylenecyclopropylformyl (MCPF)-CoA, respectively, occurred mainly in the skeletal muscles, as evidenced by very high concentrations of MCPA-carnitine and MCPF-carnitine in this tissue. Inhibition of the acyl-CoA dehydrogenases of short- and medium-chain as well as branched-chain fatty acids by the toxins led to a strong increase in the corresponding acylcarnitines, again preferentially in skeletal muscles. An accumulation of the long-chain acylcarnitines beyond the level of the control samples could not be detected in the tissues. As a high amount of HGA was always found unmetabolized in the organs, we speculate that targeting the interruption of further metabolization might be a way to stop the progression of intoxication. Inhibition of the mitochondrial branched-chain amino acid aminotransferase, i.e., the first enzyme responsible for the activation of sycamore maple protoxins, could be a therapeutic approach. [ABSTRACT FROM AUTHOR]