Metabolites

ObjectiveTo characterize changes in the plasma metabolic profile in newly diagnosed rheumatoid arthritis (RA) patients upon commencement of conventional disease modifying anti-rheumatic drug (cDMARD) therapy. MethodsPlasma samples collected in an early RA randomized strategy study (NCT00920478) that compared clinical (DAS) disease activity assessment with musculoskeletal ultrasound assessment (MSUS) to drive treatment decisions were subjected to untargeted metabolomic analysis. Metabolic profiles were collected at pre- and 3 months post commencement of non-biologic cDMARD. Metabolites that changed in association with changes in the DAS44 score were identified at the 3 month timepoint. ResultsA total of ten metabolites exhibited a clear correlation with reduction in DAS44 score following cDMARD commencement, particularly itaconate, its derived anhydride and a derivative of itaconate coA. Increasing itaconate correlated with improved DAS44 score and decreasing levels of CRP. ConclusioncDMARD treatment effects invoke consistent changes in plasma detectable metabolites, that in turn implicate clinical disease activity with macrophages. Such changes inform RA pathogenesis and reveal for the first time a link between itaconate production and resolution of an inflammatory disease in humans. Quantitative metabolic biomarker based tests of clinical change in state are feasible and should be developed around the itaconate pathway. Key MessagesO_ST_ABSWhat is already known about this subject?C_ST_ABSRheumatoid arthritis is associated with perturbations in metabolic activity, which have also been associated with response to certain treatments. In vitro work on immunometabolism has recently revealed itaconate as a key metabolite controlling macrophage activation. What does this study add?In newly diagnosed RA, commencement of csDMARD therapy is associated with changes in the levels of ten metabolites (especially itaconate and its derivatives) that correlate to a corresponding fall in disease activity Pathway analyses suggest these metabolites are associated with macrophage activation. How might this impact on clinical practice?Changes in metabolite levels in response to treatment provide additional new insights into RA pathogenesis that suggest a focus on macrophage activation state. The association of increased itaconate with decreased inflammation point to possible routes of intervention in RA.

IntroductionRheumatoid arthritis (RA) is an auto-immune disease which causes irreversible damage to tissue and cartilage within synovial joints. Rapid diagnosis and treatment with disease-modifying therapies is essential to reduce inflammation and prevent joint destruction. RA is a heterogeneous disease, and many patients do not respond to front-line therapies, requiring escalation of treatment onto biologics, of which TNF inhibitors (TNF-i) are the most common. Objectives/MethodsIn this study we determined whether serum metabolomics, using nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy, could discriminate RA blood sera from healthy human controls and whether serum metabolomics could be used to predict response or non-response to TNF inhibitor (TNF-i) therapy. ResultsNMR spectroscopy identified 35 metabolites in RA sera, with acetic acid being significantly lower in RA sera compared to healthy controls (HC, FDR<0.05). PLS-DA modelling identified 2-hydroxyisovalericacetic acid, acetoacetic acid, mobile lipids, alanine and leucine as important metabolites for discrimination of RA and HC sera by 1H NMR spectroscopy (averaged 83.1% balanced accuracy, VIP score >1). FTIR spectroscopy identified a significant difference between RA and HC sera in the 1000-1200 cm-1 spectral area, representing the mixed region of carbohydrates and nucleic acids (FDR<0.05). Sera from RA patients who responded to TNF-i were significantly different from TNF-i non-responder sera in the 1600-1700 cm-1 region (FDR<0.05). ConclusionWe propose that NMR and FTIR serum metabolomics could be used as a diagnostic tool alongside current clinical parameters to diagnose RA and to predict whether someone with severe RA will respond to TNF-i.

Metabolomics data has been generated via proton nuclear magnetic resonance (NMR) spectroscopy in samples collected within By-Band-Sleeve. Two sample collection efforts were made - firstly, from a randomised controlled trial (RCT) comparing the effectiveness of three types of bariatric surgery: the Roux-en-Y gastric bypass ("bypass"), laparoscopic adjustable gastric band ("band") and the sleeve gastrectomy ("sleeve"), and secondly from a non-randomised (observational) study of bariatric surgery. In both instances, samples were collected from patients before and after surgery. Data underwent quality control (QC) using a standard pipeline via the R package metaboprep. This package extracts data from preformed worksheets, provides summary statistics and enables the user to select samples and metabolites for their analysis based on a set of quality metrics. Post-filtering, the dataset consists of data from 1410 samples (999 pre-surgery, 411 post-surgery) from 1045 unique individuals (1000 from the RCT and 45 from the non-randomised study), each with 250 measured metabolic traits. Comparison of NMR measures to clinical chemistry data showed good agreement for the metabolites in common across both datasets. Concordance with previous NMR data generated for a subset of the same samples was largely good. Overall, this data note describes the data, explains the pre-processing and quality control procedures applied to the data, and provides some data validation analyses.

Red yeast rice (RYR) is a traditional Chinese product obtained by fermenting rice with the yeast Monascus purpureus and contains monacolin K, which is chemically identical to lovastatin, a drug with cholesterol-lowering activity. The European Food Safety Authority (EFSA) has evaluated the safety and efficacy of RYR supplements for managing cholesterol levels. In 2018, EFSA published a scientific opinion on the use of monacolin K from RYR in food supplements, concluding that monacolins from RYR may raise significant safety concerns at a use level of 10 mg/ day. Following that, the European Commission declared in 2022 that RYR products must contain less than 3 mg of monacolins for daily consumption. The aim of this work was to perform a comprehensive profiling of plasma markers of muscle and liver dysfunction by extensive untargeted plasma proteomics in healthy volunteers with suboptimal cholesterolaemia who were randomly assigned to receive a dietary supplement containing RYR (total monacolin <3 mg) or placebo for one month. No changes in classical markers of liver (AST, ALT) or muscle (CPK) function were detected in the plasma samples of patients treated with the supplement compared to placebo. Interestingly, the analysis of circulating proteins marking an early acute response in the liver, such as serum amyloid A4, orosomucoid 2, haptoglobin-related protein, prothrombin, -1-antitrypsin, -2-HS- glycoprotein, serum amyloid P (APCS), orosomucoid 1, c-reactive protein (CRP) and -2- macroglobulin confirmed an overlapping profile in the two groups. Similarly, the analysis of ryanodine receptor 1, titin, dystrophin and myosin 7 again showed a similar profile in the two groups. These data indicate that a low dose of monacolin K (<3 mg/day) in subjects with suboptimal cholesterolaemia does not increase levels of markers of liver and skeletal muscle function in plasma, excluding a deleterious effect of monacolin K on these tissues.

We describe the technology and validation of a new whole room indirect calorimeter (WRIC) methodology to quantify methane (CH4) released from the human body over 24h concurrently with the assessment of energy expenditure and substrate utilization. The new system extends the assessment of energy metabolism by adding CH4, a downstream product of microbiome fermentation that could contribute to energy balance. MethodsOur new system consists of an established whole room indirect calorimeter WRIC combined with the addition of off-axis integrated-cavity output spectroscopy (OA-ICOS) to measure CH4 concentrations ([CH4]). The volume of CH4 released (VCH4) was calculated after measuring air flow rates. Development and validation included environmental experiments to measure the stability of the atmospheric [CH4], infusing CH4 into the WRIC and cross-validation studies comparing [CH4] quantified by OA-ICOS and mid-infrared dual-comb spectroscopy (MIR DCS). Reliability of the whole system is reported between years, weeks, days, and validated CH4 infusions. The cross-validation and reliability of VCH4 released from the human body was determined in 19 participants on consecutive days. In addition, we describe a postprocessing analytical method to differentiate CH4 released from breath versus intestine by matching times of stool production and contemporaneous VCH4 release. ResultsOur infusion data indicated that the system measured 24h [CH4] and VCH4 with high sensitivity, reliability and validity. Cross-validation studies showed good agreement between OA-ICOS and MIR DCS technologies (r= 0.979, P<0.0001). Initial human data revealed 24h VCH4 was highly variable between subjects and within / between days; this highlights the importance of a 24-h continuous assessment to have a complete picture of VCH4 release. Finally, our method to quantify VCH4 released by breath or colon suggested that over 50% of the CH4 was eliminated through the breath. ConclusionsThe method allows, for the first time, measurement of 24h VCH4 (in kcal) and therefore the measurement of the proportion of human energy intake fermented to CH4 by the gut microbiome and released via breath or directly from the intestine. Our method is accurate, valid, and will provide meaningful data to understand not only interindividual variation, but also allows us to track the effects of dietary, probiotic, bacterial and fecal microbiota transplantation on VCH4.

Aims/hypothesisWhile physical activity is clearly beneficial in combating type 2 diabetes, the underlying molecular mechanisms are incompletely understood. Moreover, there is a considerable degree of variability in the individual response to exercise-based lifestyle interventions that remains to be explained. We aimed to identify novel exercise-induced metabolites that could mediate the improvement in glycemic control and reduction of obesity and contribute to individual differences in the response to exercise interventions. MethodsWe studied acute exercise- and training-induced changes in plasma metabolites in sedentary subjects with overweight (8 male, 14 female) participating in an eight-week supervised training program flanked by two acute endurance exercise sessions. Plasma metabolites were quantified using LC- and CE-MS. In a separate study (n=9 lean males), we assessed metabolite fluxes over the leg using arterial and venous catheters. Functional analyses were performed in primary blood mononuclear cells (PBMCs) stimulated with lipopolysaccharide (LPS) or the saturated fatty acid palmitate. ResultsThe amino acid breakdown products 3-phenyllactic acid (PLA), 4-hydroxyphenyllactic acid and indolelactic acid were increased after both acute exercise and training. All three aromatic lactic acids, which so far mainly received attention as bacterial metabolites, exhibited an efflux from the leg. PLA showed the largest increase after both acute exercise and training, of 57% and 20% respectively. The magnitude of the acute exercise-induced increase in PLA correlated with a decrease in subcutaneous adipose tissue volume and an improvement in insulin sensitivity over the course of the intervention. Furthermore, both isomers, D- and L-PLA, counteracted inflammatory cytokine production in PBMCs. Conclusions/interpretationOur findings indicate that PLA is physiologically released from skeletal muscle and can contribute to the anti-inflammatory effects of exercise as well as to individual difference in the response to lifestyle interventions in humans. PLA and potentially, aromatic lactic acids in general may be particularly relevant metabolic regulators because they can be produced both endogenously and by the microbiome. Trial registrationClinicalTrials.gov NCT03151590

BackgroundAcute myocardial infarction (AMI) remains a major cause of death, with limited understanding of its early risk stratification. While gut microbiome disturbances has been associated with late-stage AMI, the connection to early-stage AMI (eAMI) is less explored. MethodsUsing metabolomics and metagenomics, we analyzed 56 samples, comprising 30 eAMI patients (within 12 hours of onset) and 26 age- and gender-matched healthy controls, to discern the influence of gut microbes and their metabolites. ResultsWe found the eAMI plasma is dominated by increased long-chain fatty acids (LCFAs), 14 of which provide differentiating power of eAMI patients from HCs. Multiomics analysis reveals up to 70% of the variance in LCFAs of eAMI patients can be explained by altered gut microbiome. Higher-resolution profiling of gut bacterial species demonstrated that bacterial structural variations are mechanistically linked to LCFAs dysregulation. By in silico molecular docking and in vitro thrombogenic assay in isolated human platelets, we highlighted that eAMI-associated LCFAs contribute to platelet aggregation, a driving factor for AMI initiation. ConclusionsLCFAs hold significant potential as early biomarkers of AMI and gut microbiome contributes to altered LCFAs in eAMI. Further studies are imperative to expand upon these observations to better leverage LCFAs as a potential biomarker for eAMI and as a therapeutic target for inhibition of platelet aggregation in eAMI.

ObjectivesDevelopment of anti-drug antibodies (ADAs) is a barrier to long-term efficacy of biologic therapies in rheumatoid arthritis (RA), but no biomarkers exist to predict ADA formation. This study explored the potential of serum metabolomics to predict development of ADAs to adalimumab in patients with RA. MethodsSerum from patients with RA (n=47), treatment naive for tumour necrosis factor-alpha inhibitor therapy, were collected before, Month(M)1 and M12 following initiation of adalimumab therapy as standard of care. Sera were tested for ADAs and patients were stratified according to M12 ADA status (ADA-positive n=21; ADA-negative n=26). Serum metabolomics was performed using a NMR-based platform. Metabolomic and clinical data were analysed using machine learning (ML) to develop a signature associated with ADA development. ResultsML analysis of baseline serum metabolomics and clinical data identified a signature that distinguished patients according to their future M12 ADA status (ADA-positive/ADA-negative) prior to first adalimumab treatment (area under the receiver operator curve, AUC-ROC=0.78), which out-performed clinical parameters alone (AUC-ROC=0.78). Metabolites related to cholesterol transport including large high and very low-density lipoproteins (L-HDL/VLDL) and small low density-lipoprotein (S-LDL) and clinical markers body mass index (BMI) and erythrocyte sedimentation rate were top discriminating features. Patients stratified as ADA-positive/ADA-negative at baseline also had different serum metabolic responses to adalimumab at M1 and M12. Finally, a putative predictive score for future ADA status was generated comprising L-HDL, L-LDL, extra-large VLDL subsets and BMI. ConclusionThese results support the potential of serum metabolomics as a predictive tool for immunogenicity risk in RA. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/25334214v2_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@c749e4org.highwire.dtl.DTLVardef@1c41e49org.highwire.dtl.DTLVardef@a083f2org.highwire.dtl.DTLVardef@369fdc_HPS_FORMAT_FIGEXP M_FIG C_FIG Key messagesO_LIMachine learning models identified serum metabolomic signatures associated with future treatment immunogenicity. C_LIO_LILipid-related metabolites suggest changes in lipid metabolism could influence ADA susceptibility. C_LI

Intrahepatic cholestasis of pregnancy (ICP) is characterized by elevated plasma bile acid levels. ICP is linked to adverse metabolic outcomes, including a reported increased risk of gestational diabetes. The standard therapeutic approach for managing ICP is treatment with ursodeoxycholic acid (UDCA) and induction of labor prior to 40 weeks of gestation. To investigate bile acid and metabolic parameters after UDCA treatment, we enrolled 12 ICP patients with singleton pregnancies-half with and half without gestational diabetes-and 7 controls. Our study reveals that after UDCA treatment, notwithstanding a reduction in total bile acid and ALT levels, imbalances persist in the cholic acid (CA) to chenodeoxycholic acid (CDCA) ratio in maternal and cord blood plasma. This indicates a continued dysregulation of bile acid metabolism despite therapeutic intervention. Maternal plasma lipid analysis showed a distinct maternal dyslipidemia pattern among ICP patients, marked by elevated cholesterol levels on VLDL particles and heightened triglyceride concentrations on LDL particles, persisting even after UDCA treatment. Cord plasma lipid profiles in ICP patients exhibited elevated triglyceride and free fatty acid levels alongside a tendency toward increased {beta}-hydroxybutyrate. The changes in lipid metabolism in both maternal and cord blood correlated with the high CA/CDCA ratio, but not total bile acid levels or gestational diabetes status. Understanding the imbalances in maternal and cord bile acid and lipid profiles that persist after standard UDCA therapy provides insights for improving management strategies and mitigating the long-term consequences of ICP. News and NoteworthyThis study uncovers that despite ursodeoxycholic acid treatment, intrahepatic cholestasis of pregnancy (ICP) is associated with increases in the ratio of cholic acid to chenodeoxycholic acid in both maternal and cord blood, suggesting ongoing dysregulation of bile acid metabolism. The high cholic to chenodeoxycholic acid ratio is correlated with maternal dyslipidemia and high cord blood lipids. These findings may inform more targeted approaches to managing ICP.

Gastric Bypass surgery (GBS) represents a well-established approach to counteract human morbid obesity and its related comorbidities in modern countries. Beside its beneficial effect on weight loss and glucose homeostasis, emerging evidence suggests that GBS impacts on the circulating levels of phospho- and sphingolipids. However, long-term effects of GBS on lipid metabolism have not been explored. Thereby, we aimed to unveil to what extent GBS improves lipid homeostasis in serum and tissues from morbid obese individuals. To investigate alterations in lipidomic signatures associated with massive weight loss following GBS in morbid obese patients, we employed direct infusion tandem mass spectrometry (MS) allowing to quantify a wide range of lipid metabolites in serum and subcutaneous adipose tissue (SAT) samples. Systematic lipidomic analyses were conducted in samples collected in a longitudinal cohort of patients (cohort 1, n = 11) prior to GBS, and one year following the surgery. These novel data were cross compared with our recent lipidomic analyses conducted by the same approach in an independent cohort of morbid obese patients and lean controls, where serum and visceral adipose tissue (VAT) lipids were analysed (cohort 2, n = 39). Over 400 phospholipid and sphingolipid species have been quantified in serum and SAT (cohort 1), allowing to establish detailed lipidomic signatures associated with morbid obesity in a tissue-specific manner. Concomitant with weight loss and improvement of metabolic parameters, a massive rearrangement of lipid metabolites was observed one year following GBS. Strikingly, a substantial reduction of ceramide levels and increased amount of hexosylceramides were detected in both serum and SAT. The comparison of these new lipidomic profiles with the serum and VAT lipidomes established from lean and morbid obese subjects (cohort 2) revealed that GBS partly restored the lipid alterations associated with morbid obesity. Our study provides the first systematic analysis of the long-term lipid homeostasis modifications upon GBS in humans SAT and serum and demonstrates that lipid metabolism alterations associated with morbid obesity might be partly reversed by GBS. The research protocol was registered with the Protocol Registration and Results System at ClinicalTrial.gov [NCT03029572].

BackgroundKnee osteoarthritis (OA) is a prevalent painful degenerative disease without effective disease-modifying drugs. The rising prevalence of comorbid obesity and knee OA underscores the urgent need for effective management to delay or prevent disease progression. In a recently completed randomized, placebo-controlled trial in adults with comorbid obesity (BMI >30 kg/m{superscript 2}) and unilateral or bilateral knee OA (Kellgren-Lawrence grade II-III), we were the first to demonstrate that a 6-month prebiotic intervention (16 g/day oligofructose-enriched inulin) significantly improved physical function and metabolic health. MethodsTo elucidate the underlying mechanisms, we incorporated metagenomics, metabolomics, and machine-learning-based multi-omics integration in 30 participants who completed baseline and at least one follow-up assessment and sample collection at months 3 and 6. ResultsPrebiotic supplementation reshaped gut microbial composition and function, increasing diet-derived carbohydrate availability, mitigating excessive host-glycan degradation and mucosal barrier disruption, reducing systemic inflammation and metabolic dysregulation, and ultimately improved physical performance and metabolic health. In a diet-induced obese rat model, prebiotic treatment reduced tibial cartilage degeneration and synovial membrane thickening, providing protection against OA onset and progression through a shared inflammatory pathway. ConclusionsOur findings provide mechanistic evidence supporting the therapeutic potential of prebiotic supplementation as a conservative management in humans and as a preventive approach for obesity-related knee OA in a preclinical rat model, mediated through the gut-joint axis. Trial registrationClinicaltrials.govNCT04172688

BackgroundRheumatoid arthritis (RA) is a chronic inflammatory disease characterized by metabolic dysregulation, including altered lipid metabolism. While polyunsaturated fatty acids have been studied, the plasma levels, endogenous synthesis, and relevance of monounsaturated fatty acids (MUFAs) in RA remain unclear. This study examined plasma MUFA levels in RA and their associations with disease activity, adiposity, and intake. MethodsIn this cross-sectional study, 59 individuals with rheumatoid arthritis (RA) and 33 non-RA controls frequency-matched on age, sex, and BMI were recruited between 2017 and 2022. Clinical assessments included disease activity (DAS28), body composition, and metabolic parameters. Dietary intake was assessed using a 4-day food journal, and plasma fatty acids were quantified by gas chromatography in 82 participants with available samples. The stearoyl-CoA desaturase-1 (SCD-1) index was used as a proxy for endogenous MUFA synthesis. Associations between MUFAs and clinical variables were evaluated using univariate and multivariable regression (p<0.05). ResultsRA participants had higher waist-to-hip ratio, fat mass, fasting triglycerides, and lower physical activity than controls. Plasma palmitoleic and oleic acids and the SCD-1 index were higher in RA, whereas linoleic and arachidonic acids were lower. Saturated and omega-3 fatty acids were similar. Higher oleic and gondoic acids were independently associated with greater disease activity; oleic acid was linked to central adiposity, and palmitoleic acid was higher in women, suggesting sex- and adiposity-specific regulation. ConclusionsHigher plasma MUFAs in RA are associated with disease activity, adiposity, and sex, highlighting altered MUFA metabolism as a feature of RA and a potential target for metabolic intervention. Key MessagesO_ST_ABSWhat is already known on this topicC_ST_ABSRheumatoid arthritis (RA) involves systemic inflammation and altered lipid metabolism. While polyunsaturated fatty acids have been studied extensively, the plasma levels, endogenous synthesis, and clinical relevance of monounsaturated fatty acids (MUFAs) in RA remain unclear. What this study addsPatients with RA have higher plasma MUFAs, including oleic and palmitoleic acids, and an elevated SCD-1 index, a marker of endogenous MUFA synthesis. Higher MUFAs are associated with disease activity, central adiposity, and sex-specific patterns, independent of dietary intake. How this study might affect research, practice or policyPlasma MUFAs could serve as potential biomarkers of RA disease activity and metabolic dysregulation. These findings suggest that altered MUFA metabolism contributes to inflammatory pathways, highlighting a potential target for future research, nutritional interventions, or therapeutic strategies.

Maternal obesity poses significant risks to fetal health, influencing metabolomic profiles in newborn cord blood. Despite the growing application of metabolomics, limited research has explored how BMI-associated metabolite alterations may vary across different ethnic groups. We analyzed metabolomic data from a multi-ethnic cohort of 87 participants, including Native Hawaiian and Pacific Islander (NHPI) individuals. We used an ensemble machine learning model with a meta-learner to predict cord blood metabolomic changes associated with maternal BMI, the continuous obesity metric. The meta-learner integrated linear and nonlinear approaches and achieved significantly enhanced performance compared to the baseline linear regression model. In cord blood samples, glycine, serine, and threonine metabolism are activated by maternal obesity, while fatty acid biosynthesis and biosynthesis of unsaturated fatty acids are repressed. Some metabolites associated with these pathways show ethnicity-specific patterns. Compared to Asians and caucasians, 1,5-anhydrosorbitol, glycine, L-threonine show a unique increase from normal to obese maternally associated groups in NHPI, while PC(O-44:6) is significantly decreased in NHPI. The finding reveals the impact of maternal obesity on offspring health, and calls on future research to investigate the maternal and newborn health in underrepresented populations, such as NHPI.

The rising prevalence of obesity and insulin resistance, a risk factor for type 2 diabetes (T2D), among adolescents is a growing public health concern. Understanding the metabolic underpinnings of adiposity and insulin resistance in adolescence can provide insights into the development of metabolic dysfunction, and potentially facilitate early intervention strategies to prevent the progression of these conditions into more severe metabolic disorders in adulthood. We explored the metabolic signatures of insulin resistance, Body Mass Index (BMI), and visceral adiposity in adolescents, in both fasting and postprandial states. A meal challenge was undertaken on 18-year-olds (154 females; 144 males), and their blood metabolites were profiled using Nuclear Magnetic Resonance spectroscopy (NMR). Least Absolute Shrinkage and Selection Operator (LASSO) regression was used for modeling and variable selection, in a sex-stratified manner. The results show distinct metabolic patterns between sexes, with males showing more pronounced postprandial responses and stronger associations between blood metabolome and insulin resistance, BMI, and visceral adiposity. Key metabolites such as lipid metabolites, Branched-Chain Amino Acids (BCAAs), glucose, and Glycoprotein Acetylation (GlycA) were selected as important metabolic entities in predicting insulin resistance and adiposity in adolescence. The findings underscore the complex interplay of metabolites with metabolic health and sex, and can pave the way for developing targeted interventions and preventive strategies specifically tailored to adolescents. Such interventions can potentially mitigate the risk of progression to more severe metabolic disorders.

ObjectiveIdentify microbial and microbiota-associated metabolites in monozygotic (MZ) and dizygotic (DZ) twins discordant for type 1 diabetes (T1D) to gain insight into potential environmental factors that may influence T1D. Research Design and MethodsSerum samples from 39 twins discordant for T1D were analyzed using a semi-targeted metabolomics approach via liquid chromatography-high-resolution tandem mass spectrometry (LC-HRMS/MS). Statistical analyses identified significant metabolites (p < 0.1) within three groups: All twins (combined group), MZ twins, and DZ twins. ResultsThirteen metabolites were identified as significant. 3-indoxyl sulfate and 5-hydroxyindole were significantly reduced in T1D individuals across all groups. Carnitine was reduced, and threonine, muramic acid, and 2-oxobutyric acid were significantly elevated in both All and MZ groups. Allantoin was significantly reduced and 3-methylhistidine was significantly elevated in All and DZ groups. ConclusionsMetabolite dysregulation associated with gut dysbiosis was observed. However, further validation of our findings in a larger cohort is needed. Article HighlightsO_LIWhy did we undertake this study? We believed this cohort of twins discordant for type 1 diabetes (T1D) would allow for control over genetic variability to examine environmental factors. C_LIO_LIWhat is the specific question(s) we wanted to answer? We aimed to identify differences in microbial and microbiota-associated metabolites in twins discordant for T1D to examine the effect of the gut microbiome on T1D. C_LIO_LIWhat did we find? Thirteen metabolites were identified as significantly different. C_LIO_LIWhat are the implications of our findings? Our results show the dysregulation of several microbial metabolites in twin pairs, suggesting that the gut microbiome plays a role in the pathogenesis of T1D. C_LI

AimNovel dietary interventions focused on fasting, have gained scientific and public attention. Periodic fasting has emerged as a dietary modification promoting beneficial effects on metabolic syndrome. This study aimed to assess whether periodic fasting reduces albuminuria in patients with type 2 diabetes and diabetic nephropathy and determine whether a reduction in albuminuria relates to activation of nephropathy-driven pathways. MethodsForty patients with type 2 diabetes (HbA1c 7.8{+/-}0.2% [62.1{+/-}2.3 mmol/mol]) and increased albumin-to-creatinine ratio (ACR) were randomized to fasting-mimicking diet (FMD) (n=21) or Mediterranean diet (n=19) for six months with three-month follow-up. Primary endpoint was the difference of the change in ACR from baseline to after six months between study groups. Subgroup analysis for patients with micro-versus macroalbuminuria at baseline was performed. Secondary endpoints comprised HOMA-IR, circulating markers of dicarbonyl detoxification (MG-H1, glyoxalase-1 and hydroxyacetone), lipid oxidation (acylcarnitines), DNA-damage/repair, (yH2Ax) and senescence (suPAR). Comparison was done by ANCOVA adjusted for age, sex, weight loss and baseline values of the respective outcome. ResultsDifference of change in ACR between FMD and control group after six months was 110.3mg/g (95% CI 99.2, 121.5mg/g; P=0.45) in all patients, -30.3mg/g (95% CI -35.7, -24.9mg/g; P[&le;]0.05] in patients with microalbuminuria, and 434.0mg/g (95% CI 404.7, 463.4mg/g; P=0.23) in those with macroalbuminuria at baseline. FMD led to change in HOMA-IR of -3,8 (95% CI -5,6, -2.0; P[&le;]0.05) and in suPAR of - 156.6pg/ml (95% CI -172.9, -140.4pg/ml; P[&le;]0.05) after six months, while no change was observed in markers of dicarbonyl detoxification or DNA-damage/repair. Change in AC profile was related to patient responsiveness to ACR improvement. At follow-up only HOMA-IR reduction (-1.9 [95% CI -3.7, -0.1], P[&le;]0.05) was sustained. ConclusionsWhen accompanied by intensive diabetes care, FMD improves microalbuminuria, HOMA-IR and suPAR levels. Lack of changes in markers of dicarbonyl detoxification and DNA-damage/repair might explain the relapse of albuminuria at follow-up. Trial registrationGerman Clinical Trials Register (Deutsches Register Klinischer Studien DRKS), DRKS-ID: DRKS00014287

Emerging evidence has indicated an association between the gut microbiome and arthritis diseases including gout. This metagenomic study aims to investigate the possible role of gut microbiota in the development of gout. The results exhibit gout patients have higher abundance of Prevotella, Fusobacterium spp. and Bacteroides spp., whereas healthy controls have higher abundance of Enterobacteriaceae spp., butyrate-producing species, including Roseburia spp., Butyrivibrio spp. and Coprococcus spp. and anti-inflammatory Faecalibacterium prausnitzii. Functional analysis shows gut microbiome of gout patients have higher potential for fructose, mannose metabolism and lipid A biosynthesis, but lower potential for urate degradation and SCFAs production. Enterobacteriaceae spp. may contribute to urate degradation and provide immunostimulatory effect in healthy controls. A disease classifier based on gut microbiota shows positive performance in the discovery and validation cohorts (93.03% and 89.13% accuracy, respectively). The effect of uric-acid-lowering and anti-inflammatory drugs on the gut microbiome is mild. Integrative analyses of four additional diseases (obesity, type 2 diabetes, ankylosing spondylitis and rheumatoid arthritis) indicates gout seems to be more similar to autoimmune diseases than metabolic diseases. This work demonstrates an altered gut microbiota might influence the development of gout and provides new insights into the diagnosis and treatment of the disease.

Use of high-throughput metabolomics technologies in a variety of study designs has demonstrated a strong and consistent metabolomic signature of overweight and type 2 diabetes. However, the extent to which these metabolomic patterns can be recovered with weight loss and diabetes remission has not been investigated. We aimed to characterise the metabolomic consequences of a weight loss intervention in diabetes, within an existing randomised controlled trial - the Diabetes Remission Clinical Trial (DiRECT) - to provide insight into how weight loss-induced metabolic changes could lead to improved health. Decreases in branched chain amino acids, sugars and LDL triglycerides, and increases in sphingolipids, plasmalogens and metabolites related to fatty acid metabolism were associated with the intervention. The change in metabolomic pattern with mean 8.8kg weight loss thus reverses many features associated with the development of type 2 diabetes. Furthermore, metabolomic profiling also appears to capture variation in response to treatment seen across patients.

BackgroundObesity is a major risk factor for heart failure (HF), but the molecular mediators linking adiposity to HF remain unclear. The molecular mechanisms by which weight loss reduces the risk of HF are also unknown. Understanding these mechanisms could highlight potential therapeutic targets for all HF patients, including those who are normal weight. We aimed to identify a common metabolic perturbation profile by comparing different weight-loss interventions and to estimate their associations with HF using Mendelian randomisation (MR). MethodsWe first integrated mass spectrometry and nuclear magnetic resonance metabolomic profiling from two weight-loss interventions - a structured diet programme (DiRECT trial) and bariatric surgery (By-Band-Sleeve trial) - with estimates of the effect of life-time body mass index (BMI) exposure on metabolite levels through MR analyses, to identify a consistent BMI-metabolite signature across differing sources of BMI variation. We then assessed the impact of these BMI-metabolites on incident HF within a two sample MR framework. Results1706 metabolites were analysed across three different sources of BMI variation: bariatric surgery, dietary intervention and life-time BMI exposure. 153 (9%) showed strong evidence for association with all three exposures with concordant direction of effect, predominantly comprising lipid fractions, lipoproteins, and amino acid metabolites. Among these metabolites, 44 (29%) had evidence of causal association with at least one HF subtype in MR. Notably, circulating levels of the non-lipid metabolites N-acetylglycine and asparagine were each inversely associated with BMI and with the risk of HF and HF with preserved ejection fraction risk, respectively. Both metabolites have previously been implicated in myocardial function and HF. ConclusionsOur findings suggest that despite differences in the modality of weight loss delivery, there exists a consistent metabolomic profile coincident with weight change. Investigating the association of the identified metabolites with HF provides insights into molecular mediators of the effects of adiposity on HF and potential novel targets for therapeutic intervention.

BackgroundMetformin is the cornerstone therapy for type 2 diabetes, but gastrointestinal intolerance commonly limits dose escalation and long-term adherence. In the ProGasMet trial, multi-strain probiotic supplementation improved metformin tolerability. However, the underlying microbiome-metabolome mechanisms remain unclear. Methods and analysisWe performed an exploratory multi-omics analysis using Period 1 of a randomized, double-blind, placebo-controlled trial. Participants with metformin intolerance received a multi-strain probiotic or placebo for 12 weeks. Paired stool samples collected at baseline (Visit 2) and end of treatment (Visit 5) were available from 34 participants (68 samples). We integrated shotgun metagenomic species profiles, predicted gut metabolic modules, and untargeted faecal LC-MS metabolomics using multi-block sparse PLS (DIABLO), complemented by longitudinal feature-level analyses and associations with gastrointestinal symptom burden (QACSMI and a simplified GI score). ResultsMulti-omics integration showed moderate concordance across taxonomic, functional, and metabolomic blocks and separated probiotic from placebo profiles at 12 weeks. Bile acid-related metabolites were among the strongest contributors to group separation, with hyodeoxycholic acid and related compounds enriched in the probiotic arm. Global biodiversity and community-wide turnover did not differ materially between groups. Feature-level analyses suggested modest, directionally coherent changes in selected taxa, functional modules, and metabolites. Higher hyodeoxycholic acid concentrations at Visit 5 were associated with lower gastrointestinal symptom burden in probiotic-treated participants, a pattern not observed under placebo; statistical support was exploratory. ConclusionProbiotic supplementation may be associated with coordinated microbiome-metabolome shifts in metformin-intolerant type 2 diabetes, highlighting bile acid remodelling, particularly hyodeoxycholic acid, as a plausible mechanistic candidate for improved tolerability.