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Background: Sodium-glucose cotransporter-2 inhibitors are foundational therapy in patients with heart failure with reduced ejection fraction (HFrEF), but underlying mechanisms of benefit are not well defined. We sought to investigate the relationships between sodium-glucose cotransporter-2 inhibitor treatment, changes in metabolic pathways, and outcomes using targeted metabolomics. Methods: DEFINE-HF (Dapagliflozin Effects on Biomarkers, Symptoms and Functional Status in Patients With HF With Reduced Ejection Fraction) was a placebo-controlled trial of dapagliflozin in HFrEF. We performed targeted mass spectrometry profiling of 63 metabolites (45 acylcarnitines [markers of fatty acid oxidation], 15 amino acids, and 3 conventional metabolites) in plasma samples at randomization and 12 weeks. Using mixed models, we identified principal components analysis–defined metabolite clusters that changed differentially with treatment and examined the relationship between change in metabolite clusters and change in Kansas City Cardiomyopathy Questionnaire scores and NT-proBNP (N-terminal probrain natriuretic peptide). Models were adjusted for relevant clinical covariates and nominal P P Results: Among the 234 DEFINE-HF participants with targeted metabolomic data, the mean age was 62.0±11.1 years, 25% were women, 38% were Black, and mean ejection fraction was 27±8%. Dapagliflozin increased ketone-related and short-chain acylcarnitine as well as medium-chain acylcarnitine principal components analysis–defined metabolite clusters compared with placebo (nominal P =0.01, false discovery rate–adjusted P =0.08 for both clusters). However, ketosis (β-hydroxybutyrate levels >500 μmol/L) was achieved infrequently (3 [2.5%] in dapagliflozin arm versus 1 [0.9%] in placebo arm) and supraphysiologic levels were not observed. Increases in long-chain acylcarnitine, long-chain dicarboxylacylcarnitine, and aromatic amino acid metabolite clusters were associated with decreases in Kansas City Cardiomyopathy Questionnaire scores (ie, worse quality of life) and increases in NT-proBNP levels, without interaction by treatment group. Conclusions: In this study of targeted metabolomics in a placebo-controlled trial of sodium-glucose cotransporter-2 inhibitors in HFrEF, we observed effects of dapagliflozin on key metabolic pathways, supporting a role for altered ketone and fatty acid biology with sodium-glucose cotransporter-2 inhibitors in patients with HFrEF. Only physiologic levels of ketosis were observed. In addition, we identified several metabolic biomarkers associated with adverse HFrEF outcomes. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02653482.

Both transcriptomics and metabolomics hold promise for identifying acute coronary syndrome (ACS) but they have not been used in combination, nor have dynamic changes in levels been assessed as a diagnostic tool. We assessed integrated analysis of peripheral blood miRNA and metabolite analytes to distinguish patients with myocardial ischemia on cardiac stress testing. We isolated and quantified miRNA and metabolites before and after stress testing from seven patients with myocardial ischemia and 1:1 matched controls. The combined miRNA and metabolomic data were analyzed jointly in a supervised, dimension-reducing discriminant analysis. We implemented a baseline model (T0) and a stress-delta model. This novel integrative analysis of the baseline levels of metabolites and miRNA expression showed modest performance for distinguishing cases from controls. The stress-delta model showed worse performance. This pilot study shows potential for an integrated precision medicine approach to cardiac stress testing.The study of small sequences of ribonucleic acids (miRNAs) and byproducts of cellular metabolism (metabolites) could help us to identify important cardiac conditions such as not enough blood and oxygen supply to the heart (acute coronary syndrome). We obtained blood samples from patients getting cardiac stress tests (a noninvasive test to see if the patient has enough blood flow to their heart) before and after their test, then compared the levels of miRNAs and metabolites in them. We compared the levels in patients who had abnormal stress tests with those that had normal tests. We believe this could be a model for a new type of cardiac stress test if validated in more patients.

Insulin resistance (IR) in adolescents with obesity is associated with a sex-dependent metabolic 'signature' comprising the branched-chain amino acids (BCAAs), glutamate/glutamine, C3/C5 acylcarnitines and uric acid. Here, we compared the levels of branched-chain α-keto acids (BCKAs) and glutamate/glutamine, which are the byproducts of BCAA catabolism and uric acid among adolescents with obesity prior to and following a 6-month lifestyle-intervention program.Fasting plasma samples from 33 adolescents with obesity (16 males, 17 females, aged 12-18 year) were analysed by flow-injection tandem MS and LC-MS/MS. Multiple linear regression models were used to correlate changes in BCKAs, glutamate/glutamine and uric acid with changes in weight and insulin sensitivity as assessed by HOMA-IR, adiponectin and the ratio of triglyceride (TG) to HDL. In predictive models, BCKAs, glutamate/glutamine and uric acid at baseline were used as explanatory variables.Baseline BCKAs, glutamate/glutamine and uric acid were higher in males than females despite comparable BMI-metrics. Following lifestyle-intervention, α-keto-β-methylvalerate (α-KMV, a metabolic by product of isoleucine) decreased in males but not in females. The ratio of BCKA/BCAA trended lower in males. In the cohort as a whole, BCKAs correlated positively with the ratio of TG to HDL at baseline and HOMA-IR at 6-month-follow-up. Glutamate/glutamine was positively associated with HOMA-IR at baseline and 6-month-follow-up. A reduction in BCKAs was associated with an increase in adiponectin, and those with higher BCKAs at baseline had higher adiponectin levels at 6-month-follow-up. Interestingly those adolescents with higher uric acid levels at baseline had greater reduction in weight.BCKAs and glutamate/glutamine may serve as biomarkers of IR in adolescents with obesity, and uric acid might serve as a predictor of weight loss in response to lifestyle-intervention. Differential regulation of BCAA catabolism in adolescent males and females implicates critical roles for sex steroids in metabolic homeostasis.

Context Gestational diabetes is associated with a long-term risk of developing a disorder of glucose metabolism. However, neither the metabolic changes characteristic of gestational diabetes in a large, multi-ancestry cohort nor the ability of metabolic changes during pregnancy, beyond glucose levels, to identify women at high risk for progression to a disorder of glucose metabolism has been examined. Objective This work aims to identify circulating metabolites present at approximately 28 weeks’ gestation associated with gestational diabetes mellitus (GDM) and development of a disorder of glucose metabolism 10 to 14 years later. Methods Conventional clinical and targeted metabolomics analyses were performed on fasting and 1-hour serum samples following a 75-g glucose load at approximately 28 weeks’ gestation from 2290 women who participated in the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study. Postpartum metabolic traits included fasting and 2-hour plasma glucose following a 75-g glucose load, insulin resistance estimated by the homeostasis model assessment of insulin resistance, and disorders of glucose metabolism (prediabetes and type 2 diabetes) during the HAPO Follow-Up Study. Results Per-metabolite analyses identified numerous metabolites, ranging from amino acids and carbohydrates to fatty acids and lipids, before and 1-hour after a glucose load that were associated with GDM as well as development of a disorder of glucose metabolism and metabolic traits 10 to 14 years post partum. A core group of fasting and 1-hour metabolites mediated, in part, the relationship between GDM and postpartum disorders of glucose metabolism, with the fasting and 1-hour metabolites accounting for 15.7% (7.1%-30.8%) and 35.4% (14.3%-101.0%) of the total effect size, respectively. For prediction of a postpartum disorder of glucose metabolism, the addition of circulating fasting or 1-hour metabolites at approximately 28 weeks’ gestation showed little improvement in prediction performance compared to clinical factors alone. Conclusion The results demonstrate an association of multiple metabolites with GDM and postpartum metabolic traits and begin to define the underlying pathophysiology of the transition from GDM to a postpartum disorder of glucose metabolism.

Objectives To perform an exploratory study to identify a JDM serum metabolic profile that differs from healthy controls (HCs) and responds to immunosuppressive treatment. Methods Blood was collected from 9 HCs and 10 patients diagnosed with probable (n = 4) or definite (n = 6) JDM based on the criteria of Bohan and Peter for myositis, with 7 of the 10 providing longitudinal samples following initiation of treatment; these patients comprised the treatment-naïve cohort. Sera underwent mass spectroscopy–based measurements of targeted metabolic intermediates, including 15 amino acids, 45 acylcarnitines (ACs), 15 ceramides and 29 sphingomyelins. Principal components analysis reduced metabolites into smaller sets of factors each comprised of correlated metabolic intermediates. Factor scores and metabolite concentrations were compared with HCs using two-sample t-tests while treatment effects were evaluated using paired t-tests. Results Of eight principal components analysis–derived metabolite factors (one AC, two amino acids, three sphingosine and two ceramide), two were significantly associated with JDM: one AC factor containing mostly long-chain ACs (P = 0.049) and one ceramide factor (P Conclusion While additional validation is needed, these lipids have potential as JDM serum diagnostic and/or treatment biomarkers. Additionally, the significant association of long-chain ACs and ceramides with JDM offers insights regarding pathogenesis, implicating dysregulation of mitochondrial fatty acid β-oxidation.

Objectives We have previously demonstrated that insulin resistance (IR) in youth is associated with elevated levels of branched-chain amino acids (BCAAs). BCAAs compete with aromatic amino acids (AAA) including tryptophan, the precursor of serotonin, for uptake into β-cells and other tissues via the large neutral amino acid transporter. Serotonin has been reported to increase β-cell mass and glucose-dependent insulin secretion. In this study we have explored how BCAA, tryptophan (one of the AAA), and a subset of their metabolites are modulated in youth-onset T2D. Based on our prior studies in neuronal BCAA metabolism, we hypothesized that elevated BCAA could induce diversion of tryptophan metabolism towards production of kynurenine rather than serotonin in youth with T2D. To test this, we analyzed 24-hour urine samples and compared levels of byproducts of BCAAs and tryptophan metabolism in obese youth with T2D with those in non-diabetic obese and lean youth of comparable age, pubertal status and ethnicity. Methods 56 non-diabetic adolescents with overweight/obesity ("obese"), 42 adolescents with T2D ("T2D"), and 43 normal weight controls ("lean"), ages 12-21 years-old were studied. Weight, height, BMI, BMI% were extracted from medical charts. Body fat percent (BF%) was measured by TANITA. We also measured metabolites derived from BCAA catabolism, including the branched-chain ketoacids (BCKAs), and tryptophan metabolism, including intermediates of the serotonergic and kynurenine pathways, in spot and 24-hour urine samples by liquid chromatography/tandem-mass spectrometry (LC/MS-MS). Levels were normalized to urine creatinine. Group differences were assessed by Kruskal Wallis or ANOVA. Results Groups were comparable for age (obese 14.8 +/- 1.9; T2D 15.7 +/- 2.1 and lean 14.9 +/- 1.9-yr), pubertal status, and ethnicity. Youth with T2D were predominantly female (T2D, 28 F, 14 M; obese 33 F, 23 M and lean, 17 F, 26 M), and had highest BF% (obese 37.3 +/- 9.5; T2D 42.9 +/- 9.9; lean 20.1 +/- 6.3%; p=2.58e-22). In 24-hour urine samples, BCKAs, tryptophan, and kynurenine levels were higher in T2D (p=0.0002, p= 0.0045 and p= 0.00009 respectively) than in either lean controls or nondiabetic youth with obesity; in contrast, there were no differences between lean controls and non-diabetic youth with obesity. The levels of 5-HIAA, the principal metabolite of serotonin, were comparable across groups; however, the ratio of kynurenine/tryptophan was higher (p= 0.0112) in youth with T2D and the ratios of 5-HIAA/ tryptophan (p=0.027) and 5-HIAA/Kynurenine (p=0.0067) were lower compared to the other two groups. Those ratios were comparable between lean controls and non-diabetic youth with obesity. Conclusions Increased BCKAs are accompanied by diversion of tryptophan metabolism from the serotonin pathway to the kynurenine pathway, suggesting perturbations in both BCAA and AAA metabolism in youth-onset T2D. These alterations could contribute to development of beta-cell dysfunction and progression to T2D in youth. Presentation: Sunday, June 12, 2022 12:00 p.m. - 12:15 p.m.

Background Type 2 diabetes mellitus (DM) is associated with an increased risk of fracture despite a paradoxically higher average bone mineral density. Additional markers of fracture risk among older adults with DM are needed to identify at-risk individuals. Method The MURDOCK study is an ongoing, longitudinal cohort study, initiated in 2007, of residents in Cabarrus and surrounding counties, based in Kannapolis, North Carolina. At study enrollment, participants completed medical and health questionnaires, and provided biospecimen samples for the biorepository. In this nested case-control analysis, incident fractures since study enrollment among MURDOCK participants were identified by self-reported survey and by query of the electronic medical records (EMR). Fracture cases were matched 2: 1 by age, gender, race/ethnicity, and BMI to participants without incident fracture. Stored biorepository serum samples were analyzed for both conventional metabolites (non-esterified fatty acids (NEFA), triglycerides, lactate, and ketones) and targeted metabolomics (amino acids and acylcarnitines), using the Beckman DxC 600 clinical analyzer and flow injection electrospray ionization tandem mass spectrometry, respectively. Principal components analysis (PCA) was used to identify relevant profiles for metabolomics data. The association between incident fracture and metabolic profile was assessed using conditional logistic regression, stratified by matched group and controlled for multiple confounders including tobacco and alcohol use, medical comorbidities (e.g., coronary artery disease, congestive heart failure, chronic kidney disease, rheumatoid arthritis) and medications (e.g., insulin, metformin, thiazolidinediones). Results 107 incident fractures were identified by self-reported questionnaire and EMR query; 210 controls were matched. The study population was predominantly female (71.8%) and white (90.6%) with mean (SD) age 65.0 (7.7) years and BMI 31.8 (6.2) kg/m2. PCA identified 2 amino acid (AA) profiles: profile 1 (AA1) consisted of the branched chain amino acids, phenylalanine and tyrosine; profile 2 (AA2) consisted of serine, arginine, asparagine/aspartate (Asx) and glutamine/glutamate (Glx). After controlling for multiple risk factors, AA2 was significantly associated with incident fracture (OR 1.72, 95% CI: 1.17–2.54). NEFA were associated with lower odds of fracture (OR 0.06, 95% CI: 0.01–0.31). There was no association of fracture with other conventional metabolites, acylcarnitine factors, nor AA1. Conclusion Given association of NEFA and AA2 with incident fracture, our results indicate novel biomarkers, as well as potential mechanisms of fracture risk among older adults with DM. Higher level of NEFA was associated with lower fracture odds; though not further classified in this study, prior studies have shown direct effects of polyunsaturated and monounsaturated fatty acids on osteoclasts. Higher level of AA2, including the amino acids Glx and Asx, was associated with increased fracture odds. Prior studies have shown direct effects of Glx on both osteoblasts and osteoclasts, and Glx and Asx have also been associated with muscle mass and strength. Presentation: Saturday, June 11, 2022 12:30 p.m. - 12:45 p.m.

Maternal and paternal exercise are well-established to improve the metabolic health of adult offspring. Tissue and serum metabolites play a fundamental role in the health of an organism, but how parental exercise affects offspring tissue and serum metabolites has not yet been investigated. Here, male and female breeders were fed a high-fat diet and housed with or without running wheels before breeding (males) and before and during gestation (females). Offspring were sedentary and chow-fed and had both parents sedentary (Sed); maternal exercise (MatEx); paternal exercise (PatEx); or maternal+paternal exercise (Mat+PatEx). Adult offspring from all parental exercise groups had similar improvement in glucose tolerance and hepatic glucose production. Targeted metabolomics was performed in offspring serum, liver, and triceps muscle. Offspring from MatEx, PatEx, and Mat+PatEx each had a unique tissue metabolite signature, but Mat+PatEx offspring had an additive phenotype relative to MatEx or PatEx alone in a subset of liver and muscle metabolites. Tissue metabolites consistently indicated that the metabolites altered parental exercise were consistent with enhanced fatty acid oxidation. These data identify distinct tissue-specific adaptations and mechanisms for parental exercise-induced improvement in offspring metabolic health. Further mining of this dataset could aid the development of novel therapeutic targets to combat metabolic diseases.

Tirzepatide, a dual GIP and GLP-1 receptor agonist, delivered superior glycemic control and weight loss compared to selective GLP-1 receptor (GLP-1R) agonism in patients with type 2 diabetes (T2D). These results have fueled mechanistic studies focused on understanding how tirzepatide achieves its therapeutic efficacy. Recently, we found that treatment with tirzepatide improves insulin sensitivity in humans with T2D and obese mice in concert with a reduction in circulating levels of branched-chain amino (BCAAs) and keto (BCKAs) acids, metabolites associated with development of systemic insulin resistance (IR) and T2D. Importantly, these systemic effects were found to be coupled to increased expression of BCAA catabolic genes in thermogenic brown adipose tissue (BAT) in mice. These findings led us to hypothesize that tirzepatide may lower circulating BCAAs/BCKAs by promoting their catabolism in BAT.To address this question, we utilized a murine model of diet-induced obesity and employed stable-isotope tracer studies in combination with metabolomic analyses in BAT and other tissues.Treatment with tirzepatide stimulated catabolism of BCAAs/BCKAs in BAT, as demonstrated by increased labeling of BCKA-derived metabolites, and increases in levels of byproducts of BCAA breakdown, including glutamate, alanine, and 3-hydroxyisobutyric acid (3-HIB). Further, chronic administration of tirzepatide increased levels of multiple amino acids in BAT that have previously been shown to be elevated in response to cold exposure. Finally, chronic treatment with tirzepatide led to a substantial increase in several TCA cycle intermediates (α-ketoglutarate, fumarate, and malate) in BAT.These findings suggest that tirzepatide induces a thermogenic-like amino acid profile in BAT, an effect that may account for reduced systemic levels of BCAAs in obese IR mice.

Mobile health (mHealth) platforms can affect health behaviors but have not been rigorously tested in randomized trials.We sought to evaluate the effectiveness of a pragmatic mHealth intervention in patients with heart failure (HF) and diabetes (DM).We conducted a multicenter randomized trial in 187 patients with both HF and DM to assess an mHealth intervention to improve physical activity and medication adherence compared to usual care. The primary endpoint was change in mean daily step count from baseline through 3 months. Other outcomes included medication adherence, health-related quality of life and metabolomic profiling.The mHealth group had an increase in daily step count of 151 steps/day at 3 months, whereas the usual-care group had a decline of 162 steps/day (least squares mean between-group difference = 313 steps/day; 95% CI: 8 619; P = 0.044). Medication adherence, measured using the Voils Adherence Questionnaire, did not change from baseline to 3 months (LS-mean change -0.08 in mHealth vs -0.15 in usual care; P = 0.47). The mHealth group had an improvement in Kansas City Cardiomyopathy Questionnaire Overall Summary Score compared to the usual-care group (LS-mean difference = 5.5 points, 95% CI: 1.4, 9.6; P = 0.009). Thirteen metabolites, primarily medium- and long-chain acylcarnitines, changed differently between treatment groups from baseline to 3 months (P0.05).In patients with HF and DM, a 3-month mHealth intervention significantly improved daily physical activity, health-related quality of life and metabolomic markers of cardiovascular health but not medication adherence.Heart failure (HF) and diabetes (DM) have overlapping biological and behavioral risk factors. We conducted a multicenter randomized, clinical trial in 187 patients with both HF (regardless of ejection fraction) and DM to assess whether an mHealth intervention could improve physical activity and medication adherence. The mHealth group had an increase in mean daily step count and quality of life but not in medication adherence. Medium- and long-chain acylcarnitines changed differently in treatment groups from baseline to 3 months (P0.05). These data have important implications for designing effective lifestyle interventions in HF and DM.

Tandem pore domain acid-sensitive K+ (TASK) channels are present in cardiac tissue; however, their contribution to cardiac pathophysiology is not well understood. Here, we investigate the role of TASK-1 and TASK-3 in the pathogenesis of cardiac dysfunction using both human tissue and mouse models of genetic TASK channel loss of function. Compared with normal human cardiac tissue, TASK-1 gene expression is reduced in association with either cardiac hypertrophy alone or combined cardiac hypertrophy and heart failure. In a pressure overload cardiomyopathy model, TASK-1 global knockout (TASK-1 KO) mice have both reduced cardiac hypertrophy and preserved cardiac function compared with wild-type mice. In contrast to the TASK-1 KO mouse pressure overload response, TASK-3 global knockout (TASK-3 KO) mice develop cardiac hypertrophy and a delayed onset of cardiac dysfunction compared with wild-type mice. The cardioprotective effects observed in TASK-1 KO mice are associated with pressure overload-induced augmentation of AKT phosphorylation and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression, with consequent augmentation of cardiac energetics and fatty acid oxidation. The protective effects of TASK-1 loss of function are associated with an enhancement of physiologic hypertrophic signaling and preserved metabolic functions. These findings may provide a rationale for TASK-1 channel inhibition in the treatment of cardiac dysfunction. NEW & NOTEWORTHY The role of tandem pore domain acid-sensitive K+ (TASK) channels in cardiac function is not well understood. This study demonstrates that TASK channel gene expression is associated with the onset of human cardiac hypertrophy and heart failure. TASK-1 and TASK-3 strongly affect the development of pressure overload cardiomyopathies in genetic models of TASK-1 and TASK-3 loss of function. The effects of TASK-1 loss of function were associated with enhanced AKT phosphorylation and expression of peroxisome proliferator-activated receptor-γ coactivator-1 (PGC-1) transcription factor. These data suggest that TASK channels influence the development of cardiac hypertrophy and dysfunction in response to injury.

Elevations in circulating levels of branched-chain amino acids (BCAAs) are associated with a variety of cardiometabolic diseases and conditions. Restriction of dietary BCAAs in rodent models of obesity lowers circulating BCAA levels and improves whole-animal and skeletal-muscle insulin sensitivity and lipid homeostasis, but the impact of BCAA supply on heart metabolism has not been studied. Here, we report that feeding a BCAA-restricted chow diet to Zucker fatty rats (ZFRs) causes a shift in cardiac fuel metabolism that favors fatty acid relative to glucose catabolism. This is illustrated by an increase in labeling of acetyl-CoA from [1-13C]palmitate and a decrease in labeling of acetyl-CoA and malonyl-CoA from [U-13C]glucose, accompanied by a decrease in cardiac hexokinase II and glucose transporter 4 protein levels. Metabolomic profiling of heart tissue supports these findings by demonstrating an increase in levels of a host of fatty-acid-derived metabolites in hearts from ZFRs and Zucker lean rats (ZLRs) fed the BCAA-restricted diet. In addition, the twofold increase in cardiac triglyceride stores in ZFRs compared with ZLRs fed on chow diet is eliminated in ZFRs fed on the BCAA-restricted diet. Finally, the enzymatic activity of branched-chain ketoacid dehydrogenase (BCKDH) is not influenced by BCAA restriction, and levels of BCAA in the heart instead reflect their levels in circulation. In summary, reducing BCAA supply in obesity improves cardiac metabolic health by a mechanism independent of alterations in BCKDH activity.

That maternal and paternal exercise improve the metabolic health of adult offspring is well established. Tissue and serum metabolites play a fundamental role in the health of an organism, but how parental exercise affects offspring tissue and serum metabolites has not yet been investigated. Here, male and female breeders were fed a high-fat diet and housed with or without running wheels before breeding (males) and before and during gestation (females). Offspring were sedentary and chow fed, with parents as follows: sedentary (Sed), maternal exercise (MatEx), paternal exercise (PatEx), or maternal+paternal exercise (Mat+PatEx). Adult offspring from all parental exercise groups had similar improvement in glucose tolerance and hepatic glucose production. Targeted metabolomics was performed in offspring serum, liver, and triceps muscle. Offspring from MatEx, PatEx, and Mat+PatEx each had a unique tissue metabolite signature, but Mat+PatEx offspring had an additive phenotype relative to MatEx or PatEx alone in a subset of liver and muscle metabolites. Tissue metabolites consistently indicated that the metabolites altered with parental exercise contribute to enhanced fatty acid oxidation. These data identify distinct tissue-specific adaptations and mechanisms for parental exercise–induced improvement in offspring metabolic health. Further mining of this data set could aid the development of novel therapeutic targets to combat metabolic diseases.

Hepatic de novo lipogenesis is influenced by the branched-chain α-keto acid dehydrogenase (BCKDH) kinase (BCKDK). We aimed to determine whether circulating levels of the immediate substrates of BCKDH, the branched-chain α-ketoacids (BCKAs) and hepatic BCKDK expression are associated with the presence and severity of non-alcoholic fatty liver disease (NAFLD).Eighty metabolites (3 BCKA, 14 amino acids, 43 acylcarnitines, 20 ceramides) were quantified in plasma from 288 bariatric surgery patients with severe obesity (BMI > 35 kg/m2) with scored liver biopsy samples. Metabolite principal component analysis (PCA) factors, BCKA, branched-chain amino acids (BCAA), and the BCKA:BCAA ratio were tested for associations with steatosis grade and presence of non-alcoholic steatohepatitis (NASH). Of all analytes tested, only the valine-derived BCKA, α-ketoisovalerate, and the BCKA:BCAA ratio were associated with both steatosis grade and NASH. Gene expression analysis in liver samples from two independent bariatric surgery cohorts showed that hepatic BCKDK mRNA expression correlates with steatosis, ballooning, and levels of the lipogenic transcription factor SREBP1. Experiments in AML12 hepatocytes showed that SREBP1 inhibition lowers BCKDK mRNA expression. These findings demonstrate that higher plasma levels of BCKA and hepatic expression of BCKDK are features of human NAFLD/NASH and identify SREBP1 as a transcriptional regulator of BCKDK.

Although hematopoietic stem cell transplantation (HCT) is the only curative treatment for acute myeloid leukemia (AML), it is associated with significant treatment related morbidity and mortality. There is great need for predictive biomarkers associated with overall survival (OS) and clinical outcomes. We hypothesized that circulating metabolic, inflammatory, and immune molecules have potential as predictive biomarkers for AML patients who receive HCT treatment. This retrospective study was designed with an exploratory approach to comprehensively characterize immune, inflammatory, and metabolomic biomarkers. We identified patients with AML who underwent HCT and had existing baseline plasma samples. Using those samples (n = 34), we studied 65 blood based metabolomic and 61 immune/inflammatory related biomarkers, comparing patients with either long-term OS (≥ 3 years) or short-term OS (OS ≤ 1 years). We also compared the immune/inflammatory response and metabolomic biomarkers in younger vs. older AML patients (≤30 years vs. ≥ 55 years old). In addition, the biomarker profiles were analyzed for their association with clinical outcomes, namely OS, chronic graft versus host disease (cGVHD), acute graft versus host disease (aGVHD), infection and relapse. Several baseline biomarkers were elevated in older versus younger patients, and baseline levels were lower for three markers (IL13, SAA, CRP) in patients with OS ≥ 3 years. We also identified immune/inflammatory response markers associated with aGVHD (IL-9, Eotaxin-3), cGVHD (Flt-1), infection (D-dimer), or relapse (IL-17D, bFGF, Eotaxin-3). Evaluation of metabolic markers demonstrated higher baseline levels of medium- and long-chain acylcarnitines (AC) in older patients, association with aGVHD (lactate, long-chain AC), and cGVHD (medium-chain AC). These differentially expressed profiles merit further evaluation as predictive biomarkers.

Recurrent cancer cells that evade therapy is a leading cause of death in breast cancer patients. This risk is high for women showing an overexpression of human epidermal growth factor receptor 2 (Her2). Cells that persist can rely on different substrates for energy production relative to their primary tumor counterpart. Here, we characterize metabolic reprogramming related to tumor dormancy and recurrence in a doxycycline-induced Her2+/Neu model of breast cancer with varying times to recurrence using longitudinal fluorescence microscopy. Glucose uptake (2-NBDG) and mitochondrial membrane potential (TMRE) imaging metabolically phenotype mammary tumors as they transition to regression, dormancy, and recurrence. “Fast-recurrence” tumors (time to recurrence ~55 days), transition from glycolysis to mitochondrial metabolism during regression and this persists upon recurrence. “Slow-recurrence” tumors (time to recurrence ~100 days) rely on both glycolysis and mitochondrial metabolism during recurrence. The increase in mitochondrial activity in fast-recurrence tumors is attributed to a switch from glucose to fatty acids as the primary energy source for mitochondrial metabolism. Consequently, when fast-recurrence tumors receive treatment with a fatty acid inhibitor, Etomoxir, tumors report an increase in glucose uptake and lipid synthesis during regression. Treatment with Etomoxir ultimately prolongs survival. We show that metabolic reprogramming reports on tumor recurrence characteristics, particularly at time points that are essential for actionable targets. The temporal characteristics of metabolic reprogramming will be critical in determining the use of an appropriate timing for potential therapies; namely, the notion that metabolic-targeted inhibition during regression reports long-term therapeutic benefit.

Introduction: Metabolic substrate utilization is central to metabolic disease. Metabolic pathways linking type 2 diabetes (T2D) to major adverse cardiac events (MACE) and heart failure (HF) remain poorly understood and T2D drug effects on metabolite biomarkers could improve biological understanding and support precision medicine approaches. Hypothesis: Circulating metabolites characterizing mitochondrial dysfunction are predictors for MACE and hospitalization for HF (hHF), and are improved with exenatide. Methods: We performed targeted mass-spectrometry profiling of 60 metabolites on baseline and 12-month plasma samples from 978 participants from EXSCEL, a randomized trial of the GLP-1 receptor agonist, exenatide. Principal components analysis (PCA) was used; resultant metabolite factors were analyzed with univariate and multivariable logistic regression (adjusted for history of HF, coronary artery disease, BMI, HbA 1c , eGFR, blood pressure) for association with MACE (CV death, non-fatal MI or stroke) and hHF. Results were validated in participants from TECOS, a randomized trial of the DPP-4 inhibitor sitagliptin. Metabolite changes by treatment arm were tested. Results: Of 12 PCA metabolite factors, two nominally associated with MACE in both univariate and multivariable models and two associated with hHF in univariate, but not multivariable models ( Table ). Individual metabolites remained associated with MACE in multivariable models and with hHF in univariate models. Similar results were seen in the TECOS validation cohort. Individual metabolites decreased to a greater extent in exenatide randomized individuals compared with placebo. Conclusions: Metabolites reporting on dysregulated mitochondrial fatty acid oxidation are increased in individuals with T2D who experience MACE. These biomarkers may improve CV risk prediction models, appear to be beneficially modified by exenatide, and highlight emerging risk mechanisms.

Brown adipose tissue (BAT) is a specialized metabolic organ responsible for non-shivering thermogenesis. Recently, its activity has been shown to be critical in systemic metabolic health through its utilization and consumption of macronutrients. In the face of energetically demanding states, metabolic flexibility and systemic coordination of nutrient partitioning is requisite for health and survival. In this study, we elucidate BAT's differential transcriptional adaptations in response to multiple nutrient challenges and demonstrate its context-dependent prioritization of lipid, glucose, and amino acid metabolism. We show that the transcription factor Krüppel-like factor 15 (KLF15) plays a critical role in BAT metabolic flexibility. BAT-specific loss of KLF15 results in widespread changes in circulating metabolites and severely compromised thermogenesis in response to high energy demands, indicative of impaired nutrient utilization and metabolic flexibility. Together, our data demonstrate KLF15 in BAT plays an indispensable role in partitioning resources to maintain homeostasis and ensure survival.

Non-alcoholic fatty liver disease (NAFLD), which often co-occurs with obesity and type 2 diabetes, is the most common cause of chronic liver disease worldwide. A subset of patients with NAFLD progress to the severe form known as non-alcoholic steatohepatitis (NASH), which increases the risk of developing hepatic fibrosis, cirrhosis, and hepatocellular carcinoma. The molecular underpinnings of the progression from NAFLD to NASH in patients is poorly understood. Active enhancer landscapes are known to determine cell states and can point to key transcription factors (TF), genes, and pathways in disease pathogenesis or resistance. Also, while super-enhancers have helped reveal key disease drivers in several cancer types, they remain undefined in NASH. To define the enhancer signature of NASH-prone (NP) and NASH-resistant (NR) phenotypes in humans, we performed chromatin run-on sequencing (ChRO-seq) analysis on liver biopsies of individuals with severe obesity who were stratified into either the NP or NR group. We defined the active enhancer signature, super-enhancer linked genes, and the candidate TF networks in human NP and NR livers. Notably, we showed that NR-activated genes that are linked to NR-specific enhancers/super-enhancers are involved in serine and glycine biosynthesis (SHMT, BHMT) as well as glycine utilization (GLYAT, GATM). Overall, this study has defined for the first time the active enhancer/super-enhancer landscape and the underlying TF programs of NASH resistance in humans with obesity.

Background Whether differences in circulating long chain acylcarnitines (LCAC) are seen in heart failure (HF) patients with and without diabetes mellitus (DM), and whether these biomarkers report on exercise capacity and clinical outcomes, remains unknown. The objective of the current study was to use metabolomic profiling to identify biomarkers that report on exercise capacity, clinical outcomes, and differential response to exercise in HF patients with and without DM. Methods Targeted mass spectrometry was used to quantify metabolites in plasma from participants in the heart failure: a controlled trial investigating outcomes of exercise training (HF-ACTION) trial. Principal components analysis was used to identify 12 uncorrelated factors. The association between metabolite factors, diabetes status, exercise capacity, and time to the primary clinical outcome of all-cause mortality or all-cause hospitalization was assessed. Results A total of 664 participants were included: 359 (54%) with DM. LCAC factor levels were associated with baseline exercise capacity as measured by peak oxygen consumption (beta 0.86, p = 2 × 10−7, and were differentially associated in participants with and without DM (beta 1.58, p = 8 × 10−8 vs. 0.67, p = 9 × 10−4, respectively; p value for interaction = 0.012). LCAC levels changed to a lesser extent in participants with DM after exercise (mean ∆ 0.09, p = 0.24) than in those without DM (mean ∆ 0.16, p = 0.08). In univariate and multivariate modeling, LCAC factor levels were associated with time to the primary outcome (multivariate HR 0.80, p = 2.74 × 10−8), and were more strongly linked to outcomes in diabetic participants (HR 0.64, p = 3.21 × 10−9 v. HR 0.90, p = 0.104, p value for interaction = 0.001). When analysis was performed at the level of individual metabolites, C16, C16:1, C18, and C18:1 had the greatest associations with both exercise capacity and outcomes, with higher levels associated with worse outcomes. Similar associations with time to the primary clinical outcome were not found in a control group of patients without HF from the CATHeterization GENetics (CATHGEN) study. Conclusions LCAC biomarkers are associated with exercise status and clinical outcomes differentially in HF patients with and without DM. Impaired fatty acid substrate utilization and mitochondrial dysfunction both at the level of the skeletal muscle and the myocardium may explain the decreased exercise capacity, attenuated response to exercise training, and poor clinical outcomes seen in patients with HF and DM. Trial Registration clinicaltrials.gov Identifier: NCT00047437.

Summary: The pro-longevity enzyme SIRT6 regulates various metabolic pathways. Gene expression analyses in SIRT6 heterozygotic mice identify significant decreases in PPARα signaling, known to regulate multiple metabolic pathways. SIRT6 binds PPARα and its response element within promoter regions and activates gene transcription. Sirt6+/− results in significantly reduced PPARα-induced β-oxidation and its metabolites and reduced alanine and lactate levels, while inducing pyruvate oxidation. Reciprocally, starved SIRT6 transgenic mice show increased pyruvate, acetylcarnitine, and glycerol levels and significantly induce β-oxidation genes in a PPARα-dependent manner. Furthermore, SIRT6 mediates PPARα inhibition of SREBP-dependent cholesterol and triglyceride synthesis. Mechanistically, SIRT6 binds PPARα coactivator NCOA2 and decreases liver NCOA2 K780 acetylation, which stimulates its activation of PPARα in a SIRT6-dependent manner. These coordinated SIRT6 activities lead to regulation of whole-body respiratory exchange ratio and liver fat content, revealing the interactions whereby SIRT6 synchronizes various metabolic pathways, and suggest a mechanism by which SIRT6 maintains healthy liver. : How the pro-longevity enzyme SIRT6 coordinates between various metabolic pathways is still obscure. Here, Naiman et al. show that SIRT6 activates PPARα to promote fatty acid beta oxidation and inhibit pyruvate oxidation during fasting. This ultimately decides the energy source under nutrient-limited conditions, promoting fat usage over other energy sources. Keywords: SIRT6, PPARα, beta-oxidation, liver, deacetylase, fasting

Branched-chain amino acid (BCAA; valine, leucine and isoleucine) supplementation is often beneficial to energy expenditure; however, increased circulatinglevels of BCAA are linked to obesity and diabetes. The mechanisms of this paradox remain unclear. Here we report that, on cold exposure, brown adipose tissue (BAT) actively utilizes BCAA in the mitochondria for thermogenesis and promotes systemic BCAA clearance in mice and humans. In turn, a BAT-specific defect in BCAA catabolism attenuates systemic BCAA clearance, BAT fuel oxidation and thermogenesis, leading to diet-induced obesity and glucose intolerance. Mechanistically, active BCAA catabolism in BAT is mediated by SLC25A44, which transports BCAAs into mitochondria. Our results suggest that BAT serves as a key metabolic filter that controls BCAA clearance via SLC25A44, thereby contributing to the improvement of metabolic health.

Urine tricarboxylic acid (TCA) cycle organic anions (OAs) are elevated in diabetes and may be biomarkers for diabetic kidney disease (DKD) progression.We assessed associations of 10 urine TCA cycle OAs with estimated glomerular filtration rate (eGFR) and eGFR slope.This study is ancillary to the Simultaneous Risk Factor Control Using Telehealth to SlOw Progression of Diabetic Kidney Disease (STOP-DKD) Trial-a randomized trial of pharmacist-led medication and behavior management in 281 patients with early to moderate DKD at Duke from 2014 to 2015. We used linear mixed models to assess associations of urine TCA cycle OAs with outcomes and modelled TCA cycle OAs as: (1) the average of z-scores for each OA; and (2) principal component (PC) scores derived by principal component analysis (PCA). Untargeted urine metabolomics were added for additional discovery.Among 132 participants with 24 h urine samples (50% men; 58% Black; mean age 64 years [SD 9]; mean eGFR 74 ml/min/1.73mThus, lower urine TCA cycle OAs, most notably lower methylmalonate, ethylmalonate and citrate/isocitrate, are potential indicators of kidney impairment in early stage DKD.

The consequences of damage to the mitochondrial genome (mtDNA) are poorly understood, although mtDNA is more susceptible to damage resulting from some genotoxicants than nuclear DNA (nucDNA), and many environmental toxicants target the mitochondria. Reports from the toxicological literature suggest that exposure to early-life mitochondrial damage could lead to deleterious consequences later in life (the “Developmental Origins of Health and Disease” paradigm), but reports from other fields often report beneficial (“mitohormetic”) responses to such damage. Here, we tested the effects of low (causing no change in lifespan) levels of ultraviolet C (UVC)-induced, irreparable mtDNA damage during early development in Caenorhabditis elegans. This exposure led to life-long reductions in mtDNA copy number and steady-state ATP levels, accompanied by increased oxygen consumption and altered metabolite profiles, suggesting inefficient mitochondrial function. Exposed nematodes were also developmentally delayed, reached smaller adult size, and were rendered more susceptible to subsequent exposure to chemical mitotoxicants. Metabolomic and genetic analysis of key signaling and metabolic pathways supported redox and mitochondrial stress-response signaling during early development as a mechanism for establishing these persistent alterations. Our results highlight the importance of early-life exposures to environmental pollutants, especially in the context of exposure to chemicals that target mitochondria., Graphical abstract Image 1, Highlights • Early life mtDNA damage led to lifelong deficits in mitochondrial function. • C. elegans developed slowly and were sensitive to chemical exposures as adults. • Redox signaling is a mechanism that establishes these persistent alterations. • Data are consistent with the Developmental Origins of Health and Disease model.

Background: To provide energy for cardiopulmonary function and maintenance of blood glucose, acute aerobic exercise induces lipolysis, fatty acid oxidation (FAO), glycolysis, and glycogenolysis/gluconeogenesis. These adaptations are mediated by increases in cortisol, growth hormone (GH), and catecholamines and facilitated by a decline in insulin. Branched-chain amino acids (BCAA) also undergo catabolism during intense exercise. Here, we investigated the relationship between BCAA catabolism and metrics of cardiopulmonary function in healthy, well-developed, mature adolescent athletes undergoing an acute bout of maximal aerobic exercise.Hypothesis: We hypothesized: (a) acute maximal exercise in adolescents induces lipolysis, FAO, and BCAA catabolism associated with increases in GH and cortisol and a reduction in insulin; (b) increases in GH are associated with increases in ghrelin; and (c) metrics of cardiopulmonary function (aVO2, rVO2, aVO2/HRmax) following maximal exercise correlate with increases in GH secretion, FAO, and BCAA catabolism.Methods: Blood samples before and after maximal cardiopulmonary exercise in 11 adolescent athletes were analyzed by tandem-mass spectrometry. Paired, two-tailed student's t-tests identified significant changes following exercise. Linear regression determined if pre-exercise metabolite levels, or changes in metabolite levels, were associated with aVO2, rVO2, and aVO2/HRmax. Sex and school of origin were included as covariates in all regression analyses.Results: Following exercise there were increases in GH and cortisol, and decreases in ghrelin, but no changes in glucose or insulin concentrations. Suggesting increased lipolysis and FAO, the levels of glycerol, ketones, β-hydroxybutyrate, and acetylcarnitine concentrations increased. Pyruvate, lactate, alanine, and glutamate concentrations also increased. Plasma concentrations of valine (a BCAA) declined (p = 0.002) while valine degradation byproducts increased in association with decreases in urea cycle amino acids arginine and ornithine. Metrics of cardiopulmonary function were associated with increases in propionylcarnitine (C3, p = 0.013) and Ci4-DC/C4-DC (p < 0.01), byproducts of BCAA catabolism.Conclusions: Induction of lipolysis, FAO, gluconeogenesis, and glycogenolysis provides critical substrates for cardiopulmonary function during exercise. However, none of those pathways were significantly associated with metrics of cardiopulmonary function. The associations between rVO2, and aVO2/HRmax and C3 and Ci4-DC/C4-DC suggest that the cardiopulmonary response to maximal exercise in adolescents is linked to BCAA utilization and catabolism.

Significance Employing an intergenerational model of diet restriction (DR) that reduces weight gain, we identify differences in carbohydrate metabolic enzyme gene content of DR versus full-fed (FF) pig gut microbiomes as animals experienced a phased-feeding program administered to farm-raised pigs during their growth cycle. Gnotobiotic mice harboring DR or FF pig microbiomes and fed a corn/soy-dominated pig diet disclosed that the DR microbiome has reduced capacity to produce butyrate, a key diet-derived energy source, and alters hepatic energy metabolism. Combining studies of farm animal microbiome development with functional assays of their microbiomes in gnotobiotic mice should help generate husbandry recommendations for promoting healthy growth of animals during this time of increasing food insecurity and mandates to eliminate subtherapeutic antibiotics for growth-promotion., The concept that gut microbiome-expressed functions regulate ponderal growth has important implications for infant and child health, as well as animal health. Using an intergenerational pig model of diet restriction (DR) that produces reduced weight gain, we developed a feature-selection algorithm to identify representative characteristics distinguishing DR fecal microbiomes from those of full-fed (FF) pigs as both groups consumed a common sequence of diets during their growth cycle. Gnotobiotic mice were then colonized with DR and FF microbiomes and subjected to controlled feeding with a pig diet. DR microbiomes have reduced representation of genes that degrade dominant components of late growth-phase diets, exhibit reduced production of butyrate, a key host-accessible energy source, and are causally linked to reduced hepatic fatty acid metabolism (β-oxidation) and the selection of alternative energy substrates. The approach described could aid in the development of guidelines for microbiome stewardship in diverse species, including farm animals, in order to support their healthy growth.

Statins are a class of drug widely prescribed for the prevention of cardiovascular disease, with pleiotropic cellular effects. Statins inhibit HMG-CoA reductase (HMGCR), which converts the reactive HMG-CoA into mevalonate. Recent discoveries revealed HMG-CoA is a highly reactive metabolite that can non-enzymatically modify proteins and impact their activity. Therefore, we predicted that inhibition of HMGCR by statins would increase HMG-CoA levels and subsequent protein modifications. We found a strong increase in HMG-CoA levels, but only a single protein being modified. Fatty acid synthase (FAS) was modified on active site residues and, importantly, the modification is located on non-lysine residues. The dynamic modifications occur only on a subpool of FAS that is located near HMGCR and alters cellular signaling around the ER and Golgi. These results uncover communication between cholesterol and lipid biosynthesis by the substrate of one pathway inhibiting another in a rapid and reversible manner.

Introduction Insulin resistance in adolescents with obesity associates with a sex‐dependent metabolic ‘signature’ comprising branched‐chain amino acids (BCAAs), glutamate and C3/C5 acylcarnitines (C3/C5), implicating altered flux through BCAA catabolic pathways. Here, we investigated the effects of lifestyle intervention on BCAA catabolism and insulin sensitivity. We hypothesized (1) weight reduction and improved insulin sensitivity associate with enhanced BCAA catabolism; (2) baseline BCAAs and their metabolic by‐products predict changes in weight and insulin sensitivity during lifestyle intervention. Methods A 33 adolescents with obesity were studied before and after 6 months of lifestyle intervention. Principal component analysis and multiple linear regression models were used to correlate changes in metabolic factors with changes in weight and insulin sensitivity assessed by HOMA‐IR, adiponectin and ratio of triglyceride (TG) to HDL. Baseline metabolic factors were used as explanatory variables in prediction models. Results Weight reduction was associated with reductions in BCAA, glutamate, and C3/C5 (p = .002) and increases in urea cycle AA (p = .029), suggesting an increase in BCAA catabolism. Increases in urea cycle AA during weight reduction were associated with increases in adiponectin, a marker of insulin sensitivity. Markers of insulin resistance (high BCAA, glutamate, and C3/C5 and low urea cycle AA) at baseline predicted increases in metrics of insulin sensitivity (decreased TG/HDL and increased adiponectin) during lifestyle intervention. Conclusions Weight reduction in adolescents is associated with increases in BCAA catabolism and improvements in insulin sensitivity. Our study underscores the therapeutic potential of manipulating BCAA catabolism to treat obesity‐associated insulin resistance in adolescents and prevent progression to T2D., Insulin resistance in adolescents with obesity associates with a sex‐dependent metabolic ‘signature’ comprising branched‐chain amino acids (BCAAs), glutamate and C3/C5 acylcarnitines (C3/C5), implicating altered flux through BCAA catabolic pathways. Here, we investigated the effects of lifestyle intervention on BCAA catabolism and insulin sensitivity.

Branched-chain amino acids (BCAA) and their cognate α-ketoacids (BCKA) are elevated in an array of cardiometabolic diseases. Here we demonstrate that the major metabolic fate of uniformly-13C-labeled α-ketoisovalerate ([U-13C]KIV) in the heart is reamination to valine. Activation of cardiac branched-chain α-ketoacid dehydrogenase (BCKDH) by treatment with the BCKDH kinase inhibitor, BT2, does not impede the strong flux of [U-13C]KIV to valine. Sequestration of BCAA and BCKA away from mitochondrial oxidation is likely due to low levels of expression of the mitochondrial BCAA transporter SLC25A44 in the heart, as its overexpression significantly lowers accumulation of [13C]-labeled valine from [U-13C]KIV. Finally, exposure of perfused hearts to levels of BCKA found in obese rats increases phosphorylation of the translational repressor 4E-BP1 as well as multiple proteins in the MEK-ERK pathway, leading to a doubling of total protein synthesis. These data suggest that elevated BCKA levels found in obesity may contribute to pathologic cardiac hypertrophy via chronic activation of protein synthesis., Systemic modulation of branched-chain keto acid (BCKA) metabolism alters cardiac health. Here, the authors define the major fates of BCKA in the heart and demonstrate that acute exposure to BCKA levels found in obesity activates cardiac protein synthesis and markedly alters the heart phosphoproteome.

Skeletal muscle is a major determinant of systemic metabolic homeostasis that plays a critical role in glucose metabolism and insulin sensitivity. By contrast, despite being a major user of fatty acids, and evidence that muscular disorders can lead to abnormal lipid deposition (e.g., nonalcoholic fatty liver disease in myopathies), our understanding of skeletal muscle regulation of systemic lipid homeostasis is not well understood. Here we show that skeletal muscle Krüppel-like factor 15 (KLF15) coordinates pathways central to systemic lipid homeostasis under basal conditions and in response to nutrient overload. Mice with skeletal muscle-specific KLF15 deletion demonstrated (a) reduced expression of key targets involved in lipid uptake, mitochondrial transport, and utilization, (b) elevated circulating lipids, (c) insulin resistance/glucose intolerance, and (d) increased lipid deposition in white adipose tissue and liver. Strikingly, a diet rich in short-chain fatty acids bypassed these defects in lipid flux and ameliorated aspects of metabolic dysregulation. Together, these findings establish skeletal muscle control of lipid flux as critical to systemic lipid homeostasis and metabolic health.

There is marked heterogeneity in the response to weight loss interventions with regards to weight loss amount and metabolic improvement. We sought to identify biomarkers predictive of type 2 diabetes remission and amount of weight loss in individuals with severe obesity enrolled in the Longitudinal Assessment of Bariatric Surgery (LABS) and the Look AHEAD (Action for Health in Diabetes) studies. Targeted mass spectrometry-based profiling of 135 metabolites was performed in pre-intervention blood samples using a nested design for diabetes remission over five years (n = 93 LABS, n = 80 Look AHEAD; n = 87 remitters), and for extremes of weight loss at five years (n = 151 LABS; n = 75 with high weight loss). Principal components analysis (PCA) was used for dimensionality reduction, with PCA-derived metabolite factors tested for association with both diabetes remission and weight loss. Metabolic markers were tested for incremental improvement to clinical models, including the DiaRem score. Two metabolite factors were associated with diabetes remission: one primarily composed of branched chain amino acids (BCAA) and tyrosine (odds ratio (95% confidence interval) [OR (95% CI)] = 1.4 [1.0–1.9], p = 0.045), and one with betaine and choline (OR [95% CI] = 0.7 [0.5–0.9], p = 0.02).These results were not significant after adjustment for multiple tests. Inclusion of these two factors in clinical models yielded modest improvements in model fit and performance: in a constructed clinical model, the C-statistic improved from 0.87 to 0.90 (p = 0.02), while the net reclassification index showed improvement in prediction compared to the DiaRem score (NRI = 0.26, p = 0.0013). No metabolite factors associated with weight loss at five years. Baseline levels of metabolites in the BCAA and trimethylamine-N-oxide (TMAO)-microbiome-related pathways are independently and incrementally associated with sustained diabetes remission after weight loss interventions in individuals with severe obesity. These metabolites could serve as clinically useful biomarkers to identify individuals who will benefit the most from weight loss interventions.

Circulating branched chain amino acid (BCAA) levels are elevated in obese humans and genetically obese rodents. However, the relationship of BCAAs to insulin resistance in diet-induced obese mice, a commonly used model to study glucose homeostasis, is still ill-defined. Here we examined how high-fat high-sucrose (HFHS) or high-fat diet (HFD) feeding, with or without BCAA supplementation in water, alters the metabolome in serum/plasma and tissues in mice and whether raising circulating BCAA levels worsens insulin resistance and glucose intolerance. Neither HFHS nor HFD feeding raised circulating BCAA levels in insulin-resistant diet-induced obese mice. BCAA supplementation raised circulating BCAA and branched-chain α-keto acid levels and C5-OH/C3-DC acylcarnitines (AC) in muscle from mice fed an HFHS diet or HFD, but did not worsen insulin resistance. A set of short- and long-chain acyl CoAs were elevated by diet alone in muscle, liver, and white adipose tissue (WAT), but not increased further by BCAA supplementation. HFD feeding reduced valine and leucine oxidation in WAT but not in muscle. BCAA supplementation markedly increased valine oxidation in muscle from HFD-fed mice, while leucine oxidation was unaffected by diet or BCAA treatment. Here we establish an extensive metabolome database showing tissue-specific changes in mice on 2 different HFDs, with or without BCAA supplementation. We conclude that mildly elevating circulating BCAAs and a subset of ACs by BCAA supplementation does not worsen insulin resistance or glucose tolerance in mice. This work highlights major differences in the effects of BCAAs on glucose homeostasis in diet-induced obese mice versus data reported in obese rats and in humans.

Animal models of human diseases are classically fed purified diets that contain casein as the unique protein source. We show that provision of a mixed protein source mirroring that found in the western diet exacerbates diet-induced obesity and insulin resistance by potentiating hepatic mTORC1/S6K1 signaling as compared to casein alone. These effects involve alterations in gut microbiota as shown by fecal microbiota transplantation studies. The detrimental impact of the mixed protein source is also linked with early changes in microbial production of branched-chain fatty acids (BCFA) and elevated plasma and hepatic acylcarnitines, indicative of aberrant mitochondrial fatty acid oxidation. We further show that the BCFA, isobutyric and isovaleric acid, increase glucose production and activate mTORC1/S6K1 in hepatocytes. Our findings demonstrate that alteration of dietary protein source exerts a rapid and robust impact on gut microbiota and BCFA with significant consequences for the development of obesity and insulin resistance., Diet-induced changes in the microbiome have been associated with obesity. Here, using a mouse model, the authors show that a mixed protein source found in western diets exacerbates diet-induced obesity and insulin resistance by potentiating hepatic mTORC1/S6K1 signaling via microbial production of branched-chain fatty acids (BCFA).

The consequences of damage to the mitochondrial genome (mtDNA) are poorly understood, although mtDNA is more susceptible to damage than nuclear DNA (nucDNA), and many environmental toxicants target the mitochondria. Reports from the toxicological literature suggest that exposure to early-life mitochondrial damage could lead to deleterious consequences later in life (the “Developmental Origins of Health and Disease” paradigm) but reports from other fields often report beneficial (“mitohormetic”) responses to such damage. Here, we test the effects of low (causing no change in lifespan) levels of ultraviolet C (UVC)-induced, irreparable mtDNA damage during early development inCaenorhabditis elegans. This exposure led to life-long reductions in mtDNA copy number and steady-state ATP levels, accompanied by increased oxygen consumption and altered metabolite profiles, suggesting inefficient mitochondrial function. Exposed nematodes were also developmentally delayed, reached smaller adult size, and were rendered more susceptible to subsequent exposure to chemical mitotoxicants. Metabolomic and genetic analysis of key signaling and metabolic pathways supported redox signaling during early development as a mechanism for establishing these persistent alterations. Our results highlight the importance of early-life exposures to environmental pollutants, especially in the context of exposure to chemicals that target mitochondria.

Background Allogeneic hematopoietic stem cell transplantation (HCT) is an often curative intent treatment, however it is associated with significant gastrointestinal (GI) toxicity and treatment related mortality. Graft-versus-host disease is a significant contributor to transplant-related mortality. We performed a phase 2 trial of the somatostatin analog pasireotide to prevent gastrointestinal toxicity and GVHD after myeloablative allogeneic HCT. Methods Patients received 0.9mg pasireotide every 12 hours from the day prior to conditioning through day +4 after HCT (or a maximum of 14 days). The primary outcomes were grade 3–4 gastrointestinal toxicity through day 30 and acute GVHD. Secondary outcomes were chronic GVHD, overall survival and relapse free survival at one year. Stool and blood samples were collected from before and after HCT for analyses of stool microbiome, local inflammatory markers, and systemic inflammatory and metabolic markers. Results were compared with matched controls. Results Twenty-six patients received pasireotide and were compared to 52 matched contemporaneous controls using a 1–2 match. Grade 3–4 GI toxicity occurred in 21 (81%) patients who received pasireotide and 35 (67%) controls (p = 0.33). Acute GVHD occurred in 15 (58%) patients in the pasireotide group and 28 (54%) controls (p = 0.94). Chronic GVHD occurred in 16 patients in the pasireotide group (64%) versus 22 patients in the control group (42%) (p = 0.12). Overall survival at 1 year in the pasireotide group was 63% (95% CI: 47%,86%) versus 82% (95% CI: 72%, 93%) in controls (log-rank p = 0.006). Relapse-free survival rate at one year was 40% (95% CI: 25%, 65%) in the pasireotide group versus 78% (95% CI: 68%, 91%) in controls (log-rank p = 0.002). After controlling for the effect of relevant covariates, patients in the pasireotide group had attenuated post-HCT loss of microbial diversity. Analysis of systemic inflammatory markers and metabolomics demonstrated feasibility of such analyses in patients undergoing allogeneic HCT. Baseline level and pre-to-post transplant changes in several inflammatory markers (including MIP1a, MIP1b, TNFa, IL8Pro, and IL6) correlated with likelihood of survival. Conclusions Pasireotide did not prevent gastrointestinal toxicity or acute GVHD compared to contemporaneous controls. Pasireotide was associated with numerically higher chronic GVHD and significantly decreased OS and RFS compared to contemporaneous controls. Pasireotide may provide a locally protective effect in the stool microbiome and in local inflammation as measured by stool calprotectin, stool beta-defensin, and stool diversity index.

The myocardium is metabolically flexible; however, impaired flexibility is associated with cardiac dysfunction in conditions including diabetes and heart failure. The mitochondrial pyruvate carrier (MPC) complex, composed of MPC1 and MPC2, is required for pyruvate import into the mitochondria. Here we show that MPC1 and MPC2 expression is downregulated in failing human and mouse hearts. Mice with cardiac-specific deletion of Mpc2 (CS-MPC2−/−) exhibited normal cardiac size and function at 6 weeks old, but progressively developed cardiac dilation and contractile dysfunction, which was completely reversed by a high-fat, low-carbohydrate ketogenic diet. Diets with higher fat content, but enough carbohydrate to limit ketosis, also improved heart failure, while direct ketone body provisioning provided only minor improvements in cardiac remodelling in CS-MPC2−/− mice. An acute fast also improved cardiac remodelling. Together, our results reveal a critical role for mitochondrial pyruvate use in cardiac function, and highlight the potential of dietary interventions to enhance cardiac fat metabolism to prevent or reverse cardiac dysfunction and remodelling in the setting of MPC deficiency. Impaired myocardial metabolic flexibility is associated with cardiac dysfunction in diabetes and heart failure. McCommis et al. reveal a critical role for mitochondrial pyruvate use in cardiac function, and use dietary interventions to enhance cardiac fat metabolism in dilated cardiomyopathy.

FIT2 is a protein important for ER lipid metabolism and lipid droplet formation, but its function has remained mysterious. Becuwe et al. show that FIT2 is an acyl coenzyme A diphosphatase, and this activity is crucial for ER homeostasis and cellular lipid storage., The endoplasmic reticulum is a cellular hub of lipid metabolism, coordinating lipid synthesis with continuous changes in metabolic flux. Maintaining ER lipid homeostasis despite these fluctuations is crucial to cell function and viability. Here, we identify a novel mechanism that is crucial for normal ER lipid metabolism and protects the ER from dysfunction. We identify the molecular function of the evolutionarily conserved ER protein FIT2 as a fatty acyl–coenzyme A (CoA) diphosphatase that hydrolyzes fatty acyl–CoA to yield acyl 4′-phosphopantetheine. This activity of FIT2, which is predicted to be active in the ER lumen, is required in yeast and mammalian cells for maintaining ER structure, protecting against ER stress, and enabling normal lipid storage in lipid droplets. Our findings thus solve the long-standing mystery of the molecular function of FIT2 and highlight the maintenance of optimal fatty acyl–CoA levels as key to ER homeostasis.

BackgroundMajority of chondrosarcomas are associated with a number of genetic alterations, including somatic mutations in isocitrate dehydrogenase 1 (IDH1) andIDH2genes, but the downstream effects of these mutated enzymes on cellular metabolism and tumor energetics are unknown. AsIDHmutations are likely to be involved in malignant transformation of chondrosarcomas, we aimed to exploit metabolomic changes inIDHmutant and non-mutant chondrosarcomas.MethodsHere, we profiled over 69 metabolites in 17 patient-derived xenografts by targeted mass spectrometry to determine if metabolomic differences exist in mutantIDH1, mutantIDH2, and non-mutant chondrosarcomas. UMAP (Uniform Manifold Approximation and Projection) analysis was performed on our dataset to examine potential similarities that may exist between each chondrosarcoma based on genotype.ResultsUMAP revealed that mutantIDHchondrosarcomas possess a distinct metabolic profile compared with non-mutant chondrosarcomas. More specifically, our targeted metabolomics study revealed large-scale differences in organic acid intermediates of the tricarboxylic acid (TCA) cycle, amino acids, and specific acylcarnitines in chondrosarcomas. Lactate and late TCA cycle intermediates were elevated in mutantIDHchondrosarcomas, suggestive of increased glycolytic metabolism and possible anaplerotic influx to the TCA cycle. A broad elevation of amino acids was found in mutantIDHchondrosarcomas. A few acylcarnitines of varying carbon chain lengths were also elevated in mutantIDHchondrosarcomas, but with minimal clustering in accordance with tumor genotype. Analysis of previously published gene expression profiling revealed increased expression of several metabolism genes in mutantIDHchondrosarcomas, which also correlated to patient survival.ConclusionsOverall, our findings suggest thatIDHmutations induce global metabolic changes in chondrosarcomas and shed light on deranged metabolic pathways.

Rotenone, a mitochondrial complex I inhibitor, has been widely used to study the effects of mitochondrial dysfunction on dopaminergic neurons in the context of Parkinson’s disease. Although the deleterious effects of rotenone are well documented, we found that young adult Caenorhabditis elegans showed resistance to 24- and 48-hour rotenone exposures. To better understand the response to rotenone in C. elegans, we evaluated mitochondrial bioenergetic parameters after 24- and 48-hour exposures to 1μM or 5 μM rotenone. Results suggested upregulation of mitochondrial complexes II and V following rotenone exposure, without major changes in oxygen consumption or steady-state ATP levels after rotenone treatment at the tested concentrations. We found evidence that the glyoxylate pathway (an alternate pathway not present in higher metazoans) was induced by rotenone exposure; gene expression measurements showed increases in mRNA levels for two complex II subunits and for isocitrate lyase, the key glyoxylate pathway enzyme. Targeted metabolomics analyses showed alterations in the levels of organic acids, amino acids, and acylcarnitines, consistent with the metabolic restructuring of cellular bioenergetics pathways including activation of complex II, the glyoxylate pathway, glycolysis, and fatty acid oxidation. This expanded understanding of how C. elegans responds metabolically to complex I inhibition via multiple bioenergetic adaptations, including the glyoxylate pathway, will be useful in interrogating the effects of mitochondrial and bioenergetic stressors and toxicants.

A wide range of protein acyl modifications has been identified on enzymes across various metabolic processes; however, the impact of these modifications remains poorly understood. Protein glutarylation is a recently identified modification that can be non-enzymatically driven by glutaryl-CoA. In mammalian systems, this unique metabolite is only produced in the lysine and tryptophan oxidative pathways. To better understand the biology of protein glutarylation, we studied the relationship between enzymes within the lysine/tryptophan catabolic pathways, protein glutarylation, and regulation by the deglutarylating enzyme Sirtuin 5 (SIRT5). Here, we identify glutarylation on the lysine oxidation pathway enzyme glutaryl-CoA dehydrogenase (GCDH). We show increased GCDH glutarylation when glutaryl-CoA production is stimulated by lysine catabolism. Our data reveal glutarylation of GCDH impacts its function, ultimately decreasing lysine oxidation. We then demonstrate the ability of SIRT5 to deglutarylate GCDH, restoring its enzymatic activity. Finally, metabolomic and bioinformatic analyses indicate an expanded role for SIRT5 in regulating amino acid metabolism. Together, these data support a model whereby a feedback loop exists within the lysine/tryptophan oxidation pathway, in which glutaryl-CoA is produced, in turn inhibiting GCDH function via glutaryl modification of GCDH lysine residues, and can be relieved by SIRT5 deacylation activity.

Low potassium intake can affect cardiovascular disease (CVD) risk and cardiometabolic risk factors. We hypothesize that potassium chloride (KCl) supplementation can improve cardiovascular risk metabolomic profile. In this secondary analysis of a pilot randomized clinical trial (RCT) of 26 participants with prediabetes randomized to KCl or placebo, we performed targeted mass-spectrometry-based metabolomic profiling on baseline and 12-week (end-of-study) plasma samples. Principal component analysis (PCA) was used to reduce the many correlated metabolites into fewer, independent factors that retain most of the information in the original data. Those taking KCl had significant reductions (corresponding to lower cardiovascular risk) in the branched-chain amino acids (BCAA) factor (P = 0.004) and in valine levels (P = 0.02); and non-significant reductions in short-chain acylcarnitines (SCA) factor (P = 0.11). KCl supplementation may improve circulating BCAA levels, which may reflect improvements in overall cardiometabolic risk profile. Clinicaltrials.gov identifier: NCT02236598; https://clinicaltrials.gov/ct2/show/NCT02236598 .

ObjectiveTo establish a biorepository of clinical, metabolomic, and microbiome samples from adolescents with obesity as they undergo lifestyle modification.MethodsWe enrolled 223 adolescents aged 10-18 years with Body Mass Index ≥ 95th percentile, along with 71 healthy weight participants. We collected clinical data, fasting serum, and fecal samples at repeated intervals over 6 months. Here we present our study design, data collection methods, and an interim analysis, including targeted serum metabolite measurements and fecal 16S rRNA gene amplicon sequencing among adolescents with obesity (n=27) and healthy weight controls (n=27).ResultsAdolescents with obesity have higher serum alanine aminotransferase, C-reactive protein, and glycated hemoglobin, and lower high-density lipoprotein cholesterol when compared with healthy weight controls. Metabolomics revealed differences in branched chain amino acid related metabolites. We also observed differential abundance of specific microbial taxa and lower species diversity among adolescents with obesity when compared with the healthy weight group.ConclusionsThe Duke Pediatric Metabolism and Microbiome Study biorepository is available as a shared resource. Early findings suggest evidence of a metabolic signature of obesity unique to adolescents, along with confirmation of previously reported findings describing metabolic and microbiome markers of obesity.Clinical Trial RegistrationBiorepository: NCT02959034Observational Trial: NCT03139877What is already known about this subject?The intestinal microbiome plays an important role in adult obesity and regulation of metabolism. Although it is well-established that obesity has its roots in childhood, very little is known about the role of the microbiome in pediatric obesity and how it changes during adolescence.What are the new findings in your manuscript?This manuscript provides details of a new shared biorepository including clinical data, stool samples and plasma samples from a diverse cohort of 223 adolescents with obesity followed longitudinally over 6 months during a weight management intervention, as well as 71 adolescents with healthy weight as a comparison group.Interim analyses suggest that adolescents with obesity have microbiome signatures and metabolite profiles similar to adults, however key differences in microbial communities and metabolic by-products are identified.How might your results change the direction of research or focus of clinical practice?The POMMS biorepository will be available for investigators to use in future research, to elucidate the underlying mechanisms of obesity and related chronic health conditions.Preliminary data reveal metabolite profiles that suggest adolescence may be a window of metabolic plasticity and disease reversibilityMicrobiome and metabolomic signatures suggest potential biomarkers that may serve as prognostic or predictive factors in disease remission, or targets for future therapeutics.

Background: Urine tricarboxylic acid (TCA) cycle organic anions (OAs) are elevated in diabetes and may be biomarkers for diabetic kidney disease (DKD) progression. Methods: We conducted an ancillary study to the Simultaneous Risk Factor Control Using Telehealth to Slow Progression of Diabetic Kidney Disease (STOP-DKD) Trial - a randomized trial of pharmacist-led medication and behavior management in 281 patients with early to moderate DKD at Duke from 2014-2015. In this study, we used linear mixed models to assess associations of 10 urine TCA cycle OAs with estimated glomerular filtration rate (eGFR) and eGFR decline. TCA cycle OAs were measured in 24h urine samples by targeted MS and modeled as: (1) the average of z-scores for each OAs; and (2) factor scores derived by principal component analysis (PCA). We extended follow-up for eGFR to mid-2019 using electronic health records. Results: Among 132 participants (50% men; 58% Black; mean age 64 years [SD 9]; median eGFR 72 ml/min/1.73m2 [IQR 59-89] and urine albumin-to-creatinine [UACR] 25 mg/g [IQR 9-81]), PCA identified 3 OA metabolite factors (F). Fumarate, malate, α-ketoglutarate, citrate, lactate, and pyruvate loaded positively on F1; succinate, pyruvate, and lactate loaded negatively on F2; and methylsuccinate, ethylmalonate, and methylmalonate loaded positively on F3. Over a median follow-up of 1 year [IQR 1.3], higher average OA z score, F1, and F3 were each strongly associated with higher baseline eGFR after adjustment for age, sex, race, and log(UACR) at baseline (all p Conclusion: Lower urine TCA cycle OAs, most notably a factor comprising lower succinate, pyruvate and lactate, are potential biomarkers for faster DKD progression. Disclosure J. Lunyera: None. M. Nguyen: None. C.J. Diamantidis: None. H.B. Bosworth: Board Member; Self; Preventric Diagnostic. Consultant; Self; Abbott, Medicines Company, Novartis Pharmaceuticals Corporation. Research Support; Self; improved patient outcomes, Novo Nordisk Foundation, Otsuka Pharmaceutical Co., Ltd., Otsuka Pharmaceutical Co., Ltd., Pharma foundation, Proteus Digital Health, Proteus Digital Health, Sanofi. U.D. Patel: Board Member; Self; Goldfinch Bio. Employee; Self; Gilead Sciences, Inc. C.A. Davenport: None. J.R. Bain: None. M. Muehlbauer: None. O. Ilkayeva: None. S.H. Shah: Research Support; Self; AstraZeneca, Verily Life Sciences LLC. J. Scialla: Advisory Panel; Self; Tricida. Other Relationship; Self; GlaxoSmithKline plc., Sanofi. Funding National Institute of Diabetes and Digestive and Kidney Diseases (DK076169)

The response to weight loss intervention is heterogeneous both in weight loss amount and improvement in metabolism. We seek to identify biomarkers predictive of long-term weight loss and type 2 diabetes (T2D) remission in the Longitudinal Assessment of Bariatric Surgery (LABS) and the Look AHEAD (Action for Health in Diabetes) studies. Methods: LABS is a longitudinal observational study of 2458 consecutive cases (2006-2009) of bariatric surgery. Look AHEAD is an RCT comparing an intensive lifestyle intervention to T2D support and education in 5,145 U.S. adults with obesity and T2D enrolled between 2001-2004. Targeted mass spectrometry-based profiling of 135 metabolites was performed in pre-intervention blood samples from individuals selected based on sustained T2D remission (N=93 LABS, N=80 Look AHEAD) and extremes (top and bottom 13th percentile) of weight loss (N=151 LABS, 23 with T2D) at 4 or 5 years. We used PCA for dimensionality reduction of metabolites and logistic regression models to determine association between metabolic factors and phenotype. Improvement in model fit and net reclassification index analyses were performed to determine if metabolites improved a clinical model for predicting remission. Results: One factor composed of branched chain amino acids (BCAA) and tyrosine (p=0.045), and one composed of betaine and choline (p=0.02) were associated with T2D remission. Inclusion of these factors in a clinical prediction model improved the fit (p=0.04). Only one factor, composed of C31:1-C37:1 sphingomyelins, associated with weight loss at 5 years (p=0.036). Conclusions. Our findings define novel associations between metabolites in the BCAA and trimethylamine-N-oxide-microbiome-related pathways that are independently and incrementally associated with sustained T2D remission after weight loss. Future studies of these analytes could help in the discovery of metabolic regulatory mechanisms, and guide more personalized weight loss interventions in individuals with T2D. Disclosure L.C. Kwee: None. O. Ilkayeva: None. M. Muehlbauer: None. B.M. Wolfe: None. J.Q. Purnell: Advisory Panel; Self; Novo Nordisk A/S. H. Chen: None. C.B. Newgard: None. S.H. Shah: Research Support; Self; AstraZeneca, Verily Life Sciences LLC. Funding National Institute of Diabetes and Digestive and Kidney Diseases (R01DK108580)

OBJECTIVES: Metabolomic profiling is used to identify biological pathways and biomarkers for cardiovascular disease (CVD) and diabetes. Thus, metabolomics could be used to identify metabolic effects and demonstrate short-term efficacy of interventions designed to reduce longer-term risk of these conditions. Low potassium (K) intake has been linked to high blood pressure and increased CVD and diabetes risk. The effects of increasing K intake on metabolomic measures related to CVD and diabetes risk are not known. In this ancillary study, we tested the hypothesis that potassium chloride (KCl) supplementation would be associated with improvements in metabolomic biomarkers, such as branched-chain amino acids (BCAA) which are associated with CVD and diabetes risk. METHODS: We performed targeted mass-spectrometry-based metabolomic profiling of 60 metabolites on baseline and 12-week (end-of-study) plasma samples from 26 African-American participants with prediabetes randomized to KCl supplements vs. placebo. Principal component analysis (PCA) was used for dimensionality reduction. Univariate and multivariable analyses were used to assess differences between the two intervention arms in the changes in metabolomic factor scores and individual metabolites. RESULTS: In univariate comparisons, compared to placebo, a PCA factor composed of long-chain acylcarnitines (LCA) increased in the KCl arm (P = 0.02). In multivariable models adjusted for baseline factor score, age, and sex, this association with the LCA factor was no longer significant; but those taking KCl had significant reductions in the BCAA factor (P = 0.004) and in valine levels (P = 0.02). CONCLUSIONS: These results suggest that KCl supplementation may be associated with improvements in BCAA metabolism. Further studies among a larger population and with longer-term follow-up are warranted to verify these results and to determine if KCl supplementation may be an effective intervention for CVD and diabetes prevention. FUNDING SOURCES: NIH/Duke CTSA.

BackgroundClinically similar older adults demonstrate variable responses to health stressors, heterogeneity attributable to differences in physical resilience. However, molecular mechanisms underlying physical resilience are unknown. We previously derived a measure of physical resilience after hip fracture—the expected recovery differential (ERD)—that captures the difference between actual recovery and predicted recovery. Starting with biomarkers associated with physical performance, morbidity, mortality, and hip fracture, we evaluated associations with the ERD to identify biomarkers of physical resilience after hip fracture.MethodsIn the Baltimore Hip Studies (N = 304) sera, we quantified biomarkers of inflammation (TNFR-I, TNFR-II, sVCAM-1, and IL-6), metabolic and mitochondrial function (non-esterified fatty acids, lactate, ketones, acylcarnitines, free amino acids, and IGF-1), and epigenetic dysregulation (circulating microRNAs). We used principal component analysis, canonical correlation, and least absolute shrinkage and selection operator regression (LASSO) to identify biomarker associations with better-than-expected recovery (greater ERD) after hip fracture.ResultsParticipants with greater ERD were more likely to be women and less disabled at baseline. The complete biomarker set explained 37% of the variance in ERD (p < .001) by canonical correlation. LASSO regression identified a biomarker subset that accounted for 27% of the total variance in the ERD and included a metabolic factor (aspartate/asparagine, C22, C5:1, lactate, glutamate/mine), TNFR-I, miR-376a-3p, and miR-16-5p.ConclusionsWe identified a set of biomarkers that explained 27% of the variance in ERD—a measure of physical resilience after hip fracture. These ERD-associated biomarkers may be useful in predicting physical resilience in older adults facing hip fracture and other acute health stressors.

RATIONALE & OBJECTIVE: Patients with CKD are at elevated risk of metabolic acidosis due to impaired net acid excretion (NAE). Identifying early markers of acidosis may guide prevention in CKD. This study compared NAE in participants with and without CKD, as well as the NAE, blood pressure (BP), and metabolomic response to bicarbonate supplementation. STUDY DESIGN: randomized-order, cross-over study with controlled feeding. SETTING & PARTICIPANTS: 8 patients with CKD (estimated glomerular filtration rate 30-59 mL/min/1.73 m2 or 60-70 mL/min/1.73 m2 with albuminuria) and 6 patients without CKD. All participants had baseline serum bicarbonate between 20-28 mEq/L, did not have diabetes mellitus, and did not use alkali supplements at baseline. INTERVENTION: Participants were fed a fixed acid-load diet with bicarbonate supplementation (7 days) and with sodium chloride control (7 days) in a randomized-order, cross-over fashion. OUTCOMES: Urine NAE, 24-hour ambulatory BP, and 24-hour urine and plasma metabolomic profiles were measured after each period. RESULTS: During control, mean NAE was 28.3 ± 10.2 mEq/d overall without difference across groups (p=0.5). Urine pH, ammonium, and citrate were significantly lower in CKD versus non-CKD (each p

Progesterone is primarily a pregnancy-related hormone, produced in substantial quantities after ovulation and during gestation. Traditionally known to function via nuclear receptors for transcriptional regulation, there is also evidence of nonnuclear action. A previously identified mitochondrial progesterone receptor (PR-M) increases cellular respiration in cell models. In these studies, we demonstrated that expression of PR-M in rat H9c2 cardiomyocytes resulted in a ligand-dependent increase in oxidative cellular respiration and beta-oxidation. Cardiac expression in a TET-On transgenic mouse resulted in gene expression of myofibril proteins for remodeling and proteins involved in oxidative phosphorylation and fatty acid metabolism. In a model of increased afterload from constant transverse aortic constriction, mice expressing PR-M showed a ligand-dependent preservation of cardiac function. From these observations, we propose that PR-M is responsible for progesterone-induced increases in cellular energy production and cardiac remodeling to meet the physiological demands of pregnancy.