A functional group-guided approach to aptamers for small molecules.

Aptameric receptors are important biosensor components, yet our ability to identify them depends on the target structures. We analyzed the contributions of individual functional groups on small molecules to binding within 27 target-aptamer pairs, identifying potential hindrances to receptor isolation-for example, negative cooperativity between sterically hindered functional groups. To increase the probability of aptamer isolation for important targets, such as leucine and voriconazole, for which multiple previous selection attempts failed, we designed tailored strategies focused on overcoming individual structural barriers to successful selections. This approach enables us to move beyond standardized protocols into functional group-guided searches, relying on sequences common to receptors for targets and their analogs to serve as anchors in regions of vast oligonucleotide spaces wherein useful reagents are likely to be found.

Decreased branched-chain amino acids and elevated fatty acids during antecedent hypoglycemia in type 1 diabetes.

INTRODUCTION: Hypoglycemia is a major limiting factor in achieving recommended glycemic targets for people with type 1 diabetes. Exposure to recurrent hypoglycemia results in blunted hormonal counter-regulatory and symptomatic responses to hypoglycemia. Limited data on metabolic adaptation to recurrent hypoglycemia are available. This study examined the acute metabolic responses to hypoglycemia and the effect of antecedent hypoglycemia on these responses in type 1 diabetes. RESEARCH DESIGN AND METHODS: Twenty-one outpatients with type 1 diabetes with normal or impaired awareness of hypoglycemia participated in a study assessing the response to hypoglycemia on 2 consecutive days by a hyperinsulinemic glucose clamp. Participants underwent a period of normoglycemia and a period of hypoglycemia during the hyperinsulinemic glucose clamp. Plasma samples were taken during normoglycemia and at the beginning and the end of the hypoglycemic period. Metabolomic analysis of the plasma samples was conducted using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry. RESULTS: In total, 68 metabolites were studied. On day 1, concentrations of the branched-chain amino acids, leucine (p=3.8×10-3) and isoleucine (p=2.2×10-3), decreased during hypoglycemia. On day 2, during hypoglycemia, five amino acids (including leucine and isoleucine) significantly decreased, and two fatty acids (tetradecanoic and oleic acids) significantly increased (p<0.05). Although more metabolites responded to hypoglycemia on day 2, the responses of the single metabolites were not statistically significant between the 2 days. CONCLUSIONS: In individuals with type 1 diabetes, one episode of hypoglycemia decreases leucine and isoleucine concentrations. Antecedent hypoglycemia results in the decrement of five amino acids and increases the concentrations of two fatty acids, suggesting an alteration between the two hypoglycemic episodes, which could indicate a possible adaptation. However, more studies are needed to gain a comprehensive understanding of the consequences of these alterations. TRIAL REGISTRATION NUMBER: NCT01337362.

U-Shape Relationship between Plasma Leucine Level and Mortality in the Intensive Care Unit.

Patients in the intensive care unit (ICU) are at high risk of mortality which is not well predicted. Previous studies noted that leucine has prognostic value in a variety of diseases. This study investigated whether leucine concentration was a useful biomarker of metabolic and nutritional status and 6-month mortality in ICU. We recruited 454 subjects admitted to ICU (348 and 106 in the initiation and validation cohorts, respectively) with an acute physiology and chronic health evaluation (APACHE II) score ≥ 15. We measured plasma leucine concentrations, traditional biomarkers, and calculated APACHE II and sequential organ failure assessment (SOFA) scores. Leucine levels were weakly correlated with albumin, prealbumin, and transferrin levels (r = 0.30, 0.12, and 0.15, p = 0.001, 0.029, and 0.007, respectively). During follow-up, 116 (33.3%) patients died. Compared to patients with leucine levels between 109 and 174 µM, patients with leucine > 174 µM or <109 µM had a lower cumulative survival rate. Death was also associated with age, higher APACHE II and SOFA scores, C-reactive protein, and longer stays in the ICU, but with lower albumin, prealbumin, and transferrin. Patients with leucine levels > 174 µM had higher alanine aminotransferase levels, but no significant differences in other variables; patients with leucine levels < 109 µM had higher APACHE II and SOFA scores, higher incidence of using inotropic agents, longer ICU and hospital stays, but lower albumin and transferrin levels. Multivariable analysis demonstrated that leucine > 174 µM was an independent predictor of mortality, especially early mortality. However, among patients who stayed in ICU longer than two weeks, leucine < 109 µM was an independent predictor of mortality. In addition, leucine < 109 µM was associated with worse ventilator weaning profiles. These findings were similar in the validation cohort. Our study demonstrated a U-shape relationship between leucine levels and mortality rate in ICU.

Deficiency in the Essential Amino Acids l-Isoleucine, l-Leucine and l-Histidine and Clinical Measures as Predictors of Moderate Depression in Elderly Women: A Discriminant Analysis Study.

Increases in depression are common in some elderly women. Elderly women often show moderate depressive symptoms, while others display minimal depressive symptoms. These discrepancies have produced contradictory and inconclusive outcomes, which have not been explained entirely by deficits in neurotransmitter precursors. Deficiency in some amino acids have been implicated in major depression, but its role in non-clinical elderly women is not well known. An analysis of essential amino acids, depression and the use of discriminant analysis can help to clarify the variation in depressive symptoms exhibited by some elderly women. The aim was to investigate the relationship of essential amino acids with affective, cognitive and comorbidity measures in elderly women without major depression nor severe mood disorders or psychosis, specifically thirty-six with moderate depressive symptoms and seventy-one with minimal depressive symptoms. The plasma concentrations of nineteen amino acids, Beck Depression Inventory (BDI) scores, Geriatric Depression Scale (GDS) scores, global cognitive scores and comorbidities were submitted to stepwise discriminant analysis to identify predictor variables. Seven predictors arose as important for belong to the group based on amino acid concentrations, with the moderate depressive symptoms group characterized by higher BDI, GDS and cognitive scores; fewer comorbidities; and lower levels of l-histidine, l-isoleucine and l-leucine. These findings suggest that elderly women classified as having moderate depressive symptoms displayed a deficiency in essential amino acids involved in metabolism, protein synthesis, inflammation and neurotransmission.

Branched-Chain Amino Acids and Risk of Breast Cancer.

Background: Circulating branched-chain amino acid (BCAA) levels reflect metabolic health and dietary intake. However, associations with breast cancer are unclear. Methods: We evaluated circulating BCAA levels and breast cancer risk within the Nurses' Health Study (NHS) and NHSII (1997 cases and 1997 controls). A total of 592 NHS women donated 2 blood samples 10 years apart. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) of breast cancer risk in multivariable logistic regression models. We conducted an external validation in 1765 cases in the Women's Health Study (WHS). All statistical tests were 2-sided. Results: Among NHSII participants (predominantly premenopausal at blood collection), elevated circulating BCAA levels were associated with lower breast cancer risk (eg, isoleucine highest vs lowest quartile, multivariable OR = 0.86, 95% CI = 0.65 to 1.13, P trend = .20), with statistically significant linear trends among fasting samples (eg, isoleucine OR = 0.74, 95% CI = 0.53 to 1.05, P trend = .05). In contrast, among postmenopausal women, proximate measures (<10 years from blood draw) were associated with increased breast cancer risk (eg, isoleucine OR = 1.63, 95% CI = 1.12 to 2.39, P trend = .01), with stronger associations among fasting samples (OR = 1.73, 95% CI = 1.15 to 2.61, P trend = .01). Distant measures (10-20 years since blood draw) were not associated with risk. In the WHS, a positive association was observed for distant measures of leucine among postmenopausal women (OR = 1.23, 95% CI = 0.96 to 1.58, P trend = .04). Conclusions: No statistically significant associations between BCAA levels and breast cancer risk were consistent across NHS and WHS or NHSII and WHS. Elevated circulating BCAA levels were associated with lower breast cancer risk among predominantly premenopausal NHSII women and higher risk among postmenopausal women in NHS but not in the WHS. Additional studies are needed to understand this complex relationship.

Branched-Chain Amino Acids Can Predict Mortality in ICU Sepsis Patients.

Sepsis biomarkers and potential therapeutic targets are urgently needed. With proton nuclear magnetic resonance (1H NMR) spectroscopy, several metabolites can be assessed simultaneously. Fifty-three adult medical ICU sepsis patients and 25 ICU controls without sepsis were prospectively enrolled. 1H NMR differences between groups and associations with 28-day and ICU mortality were investigated. In multivariate metabolomic analyses, we found separate clustering of ICU controls and sepsis patients, as well as septic shock survivors and non-survivors. Lipoproteins were significantly different between sepsis and control patients. Levels of the branched-chain amino acids (BCAA) valine (median 43.3 [29.0-53.7] vs. 64.3 [47.7-72.3] normalized signal intensity units; p = 0.005), leucine (57.0 [38.4-71.0] vs. 73.0 [54.3-86.3]; p = 0.034) and isoleucine (15.2 [10.9-21.6] vs. 17.9 [16.1-24.4]; p = 0.048) were lower in patients with septic shock compared to those without. Similarly, BCAA were lower in ICU non-survivors compared to survivors, and BCAA were good discriminators for ICU and 28-day mortality. In uni- and multivariable logistic regression analyses, higher BCAA levels were associated with decreased ICU- and 28-day mortality. In conclusion, metabolomics using 1H NMR spectroscopy showed encouraging potential for personalized medicine in sepsis. BCAA was significantly lower in sepsis non-survivors and may be used as early biomarkers for outcome prediction.

Effects of PPM1K rs1440581 and rs7678928 on serum branched-chain amino acid levels and risk of cardiovascular disease.

OBJECTIVE: This study aimed to investigate the effects of PPM1K rs1440581 and rs7678928 single nucleotide polymorphisms (SNPs) on the serum branched-chain amino acids (BCAAs) levels and cardiovascular disease (CVD) risk. METHODS: Anthropometric and biochemical examinations were performed at baseline and the end of 4 years in 234 individuals who were randomly recruited from the Diabetes Prevention Programme in Huai'an and received lifestyle intervention and follow up for 4 years. Serum BCAAs (leucine, isoleucine and valine (Val)) levels were measured by hydrophilic interaction chromatography-tandem mass spectrometric method and the PPM1K rs1440581 and rs7678928 were detected by high-throughput SNP genotyping at baseline. The associations of rs1440581 and rs7678928 with serum BCAA levels and risk for CVD after 4 years were further evaluated. RESULTS: The distribution frequencies of PPM1K rs1440581 and rs7678928 met the Hardy-Weinberg equilibrium (p> .05). The baseline serum levels of Val (p = .022) and total BCAAs (p = .026) in subjects with rs1440581 CC genotype were higher than in those with TT genotype. There were no significant differences in the serum levels of BCAAs among subjects with different genotypes of rs7678928. After 4-year follow-up, the subjects with rs1440581 CC genotype had higher systolic blood pressure (SBP) (p = .027), diastolic blood pressure (DBP) (p = .019), triglycerides (TGs) (p = .019) and lower high-density lipoprotein cholesterol (HDL-c) (p = .008) than those with TT genotype, and had higher AST level than those with TT (p = .030) or TC (p = .003) genotype; the subjects with rs7678928 TT genotype had higher SBP (p = .039) and DBP (p = .019) and lower HDL-c than those with CC (p = .017) genotype. Lifestyle intervention had little influence on the serum levels of fasting plasma glucose (FPG), TG, HDL-c, alanine aminotransferase (ALT), AST and creatinine (CREA) in subjects with rs1440581 CC genotype or rs7678928 TT genotype (p> .05). The incidences of CVD and non-alcoholic fatty liver disease (NAFLD) in subjects with rs1440581 CC genotype were higher than in those with TT genotype; the incidence of CVD in subjects with rs7678928 TT genotype was higher than in those with CC (p < .05) genotype. CONCLUSIONS: Allele C of PPM1K rs1440581 was associated with elevated serum Val, total BCAAs and CVD risks. rs1440581 CC genotype may be a better marker than baseline serum BCAAs in predicting the risk for CVD. TRIAL REGISTRATION: Diabetes Prevention Programme in Huai'an of Huai'an Second People's Hospital, ChiCTR-TRC-14005029.KEY MESSAGEAllele C of PPM1K rs1440581 was relevant to elevated serum Val and total BCAAs.PPM1K rs1440581 CC and rs7678928 TT genotypes were associated with CVD risk.PPM1K rs1440581 CC genotype carriers were more likely to have liver injury and develop NAFLD.

How to Screen and Prevent Metabolic Syndrome in Patients of PCOS Early: Implications From Metabolomics.

Background: Polycystic ovary syndrome (PCOS) is a complex reproductive endocrine disorder. And metabolic syndrome (MS) is an important bridge for PCOS patients to develop other diseases, such as diabetes and coronary heart disease. Our aim was to study the potential metabolic characteristics of PCOS-MS and identify sensitive biomarkers so as to provide targets for clinical screening, diagnosis, and treatment. Methods: In this study, 44 PCOS patients with MS, 34 PCOS patients without MS, and 32 healthy controls were studied. Plasma samples of subjects were tested by ultraperformance liquid chromatography (UPLC) system combined with LTQ-orbi-trap mass spectrometry. The changes of metabolic characteristics from PCOS to PCOS-MS were systematically analyzed. Correlations between differential metabolites and clinical characteristics of PCOS-MS were assessed. Differential metabolites with high correlation were further evaluated by the receiver operating characteristic (ROC) curve to identify their sensitivity as screening indicators. Results: There were significant differences in general characteristics, reproductive hormone, and metabolic parameters in the PCOS-MS group when compared with the PCOS group and healthy controls. We found 40 differential metabolites which were involved in 23 pathways when compared with the PCOS group. The metabolic network further reflected the metabolic environment, including the interaction between metabolic pathways, modules, enzymes, reactions, and metabolites. In the correlation analysis, there were 11 differential metabolites whose correlation coefficient with clinical parameters was greater than 0.4, which were expected to be taken as biomarkers for clinical diagnosis. Besides, these 11 differential metabolites were assessed by ROC, and the areas under curve (AUCs) were all greater than 0.7, with a good sensitivity. Furthermore, combinational metabolic biomarkers, such as glutamic acid + leucine + phenylalanine and carnitine C 4: 0 + carnitine C18:1 + carnitine C5:0 were expected to be sensitive combinational biomarkers in clinical practice. Conclusion: Our study provides a new insight to understand the pathogenesis mechanism, and the discriminating metabolites may help screen high-risk of MS in patients with PCOS and provide sensitive biomarkers for clinical diagnosis.

M2 macrophage accumulation contributes to pulmonary fibrosis, vascular dilatation, and hypoxemia in rat hepatopulmonary syndrome.

Hepatopulmonary syndrome (HPS) markedly increases the mortality of patients. However, its pathogenesis remains incompletely understood. Rat HPS develops in common bile duct ligation (CBDL)-induced, but not thioacetamide (TAA)-induced cirrhosis. We investigated the mechanisms of HPS by comparing these two models. Pulmonary histology, blood gas exchange, and the related signals regulating macrophage accumulation were assessed in CBDL and TAA rats. Anti-polymorphonuclear leukocyte (antiPMN) and anti-granulocyte-macrophage colony stimulating factor (antiGM-CSF) antibodies, clodronate liposomes (CL), and monocyte chemoattractant protein 1 (MCP1) inhibitor (bindarit) were administrated in CBDL rats, GM-CSF, and MCP1 were administrated in bone marrow-derived macrophages (BMDMs). Pulmonary inflammatory cell recruitment, vascular dilatation, and hypoxemia were progressively developed by 1 week after CBDL, but only occurred at 4 week after TAA. Neutrophils were the primary inflammatory cells within 3 weeks after CBDL and at 4 week after TAA. M2 macrophages were the primary inflammatory cells, meantime, pulmonary fibrosis, GM-CSFR, and CCR2 were specifically increased from 4 week after CBDL. AntiPMN antibody treatment decreased neutrophil and macrophage accumulation, CL or the combination of antiGM-CSF antibody and bindarit treatment decreased macrophage recruitment, resulting in pulmonary fibrosis, vascular dilatation, and hypoxemia in CBDL rats alleviated. The combination treatment of GM-CSF and MCP1 promoted cell migration, M2 macrophage differentiation, and transforming growth factor-ß1 (TGF-ß1) production in BMDMs. Conclusively, our results highlight neutrophil recruitment mediates pulmonary vascular dilatation and hypoxemia in the early stage of rat HPS. Further, M2 macrophage accumulation induced by GM-CSF/GM-CSFR and MCP1/CCR2 leads to pulmonary fibrosis and promotes vascular dilatation and hypoxemia, as a result, HPS develops.

Alcohol Acutely Antagonizes Refeeding-Induced Alterations in the Rag GTPase-Ragulator Complex in Skeletal Muscle.

The Ragulator protein complex is critical for directing the Rag GTPase proteins and mTORC1 to the lysosome membrane mediating amino acid-stimulated protein synthesis. As there is a lack of evidence on alcohol's effect on the Rag-Ragulator complex as a possible mechanism for the development of alcoholic skeletal muscle wasting, the aim of our study was to examine alterations in various protein-protein complexes in the Rag-Ragulator pathway produced acutely by feeding and how these are altered by alcohol under in vivo conditions. Mice (C57Bl/6; adult males) were fasted, and then provided rodent chow for 30 min ("refed") or remained food-deprived ("fasted"). Mice subsequently received ethanol (3 g/kg ethanol) or saline intraperitoneally, and hindlimb muscles were collected 1 h thereafter for analysis. Refeeding-induced increases in myofibrillar and sarcoplasmic protein synthesis, and mTOR and S6K1 phosphorylation, were prevented by alcohol. This inhibition was not associated with a differential rise in the intracellular leucine concentration or plasma leucine or insulin levels. Alcohol increased the amount of the Sestrin1•GATOR2 complex in the fasted state and prevented the refeeding-induced decrease in Sestrin1•GATOR2 seen in control mice. Alcohol antagonized the increase in the RagA/C•Raptor complex formation seen in the refed state. Alcohol antagonized the increase in Raptor with immunoprecipitated LAMPTOR1 (part of the Ragulator complex) after refeeding and decreased the association of RagC with LAMPTOR1. Finally, alcohol increased the association of the V1 domain of v-ATPase with LAMPTOR1 and prevented the refeeding-induced decrease in v-ATPase V1 with LAMPTOR1. Overall, these data demonstrate that acute alcohol intake disrupts multiple protein-protein complexes within the Rag-Ragulator complex, which are associated with and consistent with the concomitant decline in nutrient-stimulated muscle protein synthesis under in vivo conditions.

Differences in gene expression of enzymes involved in branched-chain amino acid metabolism of abdominal subcutaneous adipose tissue between pregnant women with and without PCOS.

OBJECTIVE: Polycystic ovary syndrome (PCOS) appears to be a common endocrine disorder of women in reproductive age. Adipose tissue (AT) is known as an active tissue in the metabolism of branched-chain amino acids (BCAA; Valine, Leucine, and Isoleucine) that they have associated with blood BCAA levels is a prognostic factor for insulin-resistant. Although the crucial roles of AT in women suffering from PCOS was reported, little information exists on the BCAA metabolism in AT of PCOS women. The aim was to assess and compare the expression of BCAAs metabolism pathway genes in abdominal subcutaneous AT of pregnant women with PCOS and non-PCOS pregnant women. MATERIALS AND METHODS: AT samples from 13 PCOS were compared with samples collected from 6 non-PCOS women, all of whom underwent caesarean. Quantitative real-time PCR technique was used for gene expression of branched chain aminotransferase 2 mitochondrial (BCAT2), branched chain ketoacid dehydrogenase E1-alpha (BCKDHA), branched chain ketoacid dehydrogenase E1-Beta (BCKDHB), dihydrolipoamide branched chain transacylase E2 (DBT), dihydrolipoamide dehydrogenase E3 (DLD), branched chain ketoacid dehydrogenase kinase (BCKDK), Data were analyzed using t-test or U-test. RESULTS: No significant differences were found in age and body mass index (BMI) between non-PCOS and PCOS women. The mRNA level of BCAT2 and DLD in PCOS group was not significantly different from non-PCOS group whereas mRNA level of BCKDHB and DBT was significantly increased in PCOS group (P < 0.0001). In contrast, mRNA level of BCKDHA (P = 0.0001) and BCKDK (P < 0.0001) was significantly decreased in PCOS group. CONCLUSION: The alterations in gene expressions involved BCAA metabolism in age-matched and BMI- matched non-PCOS and PCOS pregnant women at delivery day was shown which warrants further studies regards functional activity. More attention should be given to AT of PCOS mothers that was previously ignored.

Triangulating evidence from longitudinal and Mendelian randomization studies of metabolomic biomarkers for type 2 diabetes.

The number of people affected by Type 2 diabetes mellitus (T2DM) is close to half a billion and is on a sharp rise, representing a major and growing public health burden. Given its mild initial symptoms, T2DM is often diagnosed several years after its onset, leaving half of diabetic individuals undiagnosed. While several classical clinical and genetic biomarkers have been identified, improving early diagnosis by exploring other kinds of omics data remains crucial. In this study, we have combined longitudinal data from two population-based cohorts CoLaus and DESIR (comprising in total 493 incident cases vs. 1360 controls) to identify new or confirm previously implicated metabolomic biomarkers predicting T2DM incidence more than 5 years ahead of clinical diagnosis. Our longitudinal data have shown robust evidence for valine, leucine, carnitine and glutamic acid being predictive of future conversion to T2DM. We confirmed the causality of such association for leucine by 2-sample Mendelian randomisation (MR) based on independent data. Our MR approach further identified new metabolites potentially playing a causal role on T2D, including betaine, lysine and mannose. Interestingly, for valine and leucine a strong reverse causal effect was detected, indicating that the genetic predisposition to T2DM may trigger early changes of these metabolites, which appear well-before any clinical symptoms. In addition, our study revealed a reverse causal effect of metabolites such as glutamic acid and alanine. Collectively, these findings indicate that molecular traits linked to the genetic basis of T2DM may be particularly promising early biomarkers.

Exercise Plus Presleep Protein Ingestion Increases Overnight Muscle Connective Tissue Protein Synthesis Rates in Healthy Older Men.

Protein ingestion and exercise stimulate myofibrillar protein synthesis rates. When combined, exercise further increases the postprandial rise in myofibrillar protein synthesis rates. It remains unclear whether protein ingestion with or without exercise also stimulates muscle connective tissue protein synthesis rates. The authors assessed the impact of presleep protein ingestion on overnight muscle connective tissue protein synthesis rates at rest and during recovery from resistance-type exercise in older men. Thirty-six healthy, older men were randomly assigned to ingest 40 g intrinsically L-[1-13C]-phenylalanine and L-[1-13C]-leucine-labeled casein protein (PRO, n = 12) or a nonprotein placebo (PLA, n = 12) before going to sleep. A third group performed a single bout of resistance-type exercise in the evening before ingesting 40 g intrinsically-labeled casein protein prior to sleep (EX+PRO, n = 12). Continuous intravenous infusions of L-[ring-2H5]-phenylalanine and L-[1-13C]-leucine were applied with blood and muscle tissue samples collected throughout overnight sleep. Presleep protein ingestion did not increase muscle connective tissue protein synthesis rates (0.049 ± 0.013 vs. 0.060 ± 0.024%/hr in PLA and PRO, respectively; p = .73). Exercise plus protein ingestion resulted in greater overnight muscle connective tissue protein synthesis rates (0.095 ± 0.022%/hr) when compared with PLA and PRO (p < .01). Exercise increased the incorporation of dietary protein-derived amino acids into muscle connective tissue protein (0.036 ± 0.013 vs. 0.054 ± 0.009 mole percent excess in PRO vs. EX+PRO, respectively; p < .01). In conclusion, resistance-type exercise plus presleep protein ingestion increases overnight muscle connective tissue protein synthesis rates in older men. Exercise enhances the utilization of dietary protein-derived amino acids as precursors for de novo muscle connective tissue protein synthesis during overnight sleep.

Bariatric surgery reduces branched-chain amino acids' levels: a systematic review and meta-analysis.

Bariatric surgery is a metabolic surgery known to be an efficient treatment for weight loss, with adequate long-term maintenance. Interestingly, some studies have reported a reduction in branched chained amino acids (BCAAs) after bariatric surgery, which putatively contributes to post-surgical metabolic improvement. The current systematic review and meta-analysis investigated the effect of bariatric surgery on the level of BCAAs. PubMed, SCOPUS, EMBASE, and Web of Science databases were searched from their inception to July 2019. All clinical trials which investigated the effect of bariatric surgery on the levels of valine, leucine, and isoleucine, for more than one week, were included. Nine studies (11 effect sizes) were analyzed via meta-analytical techniques using random-effects models. The pooled data suggested that bariatric surgery significantly reduced the valine (standardized mean difference [SMD]: -1.89, 95% confidence interval [CI]: -2.79, -0.99, I2 = 90.9%), leucine (SMD: -0.96, 95% CI: -1.48, -0.44, I2 = 72.4%), and isoleucine (SMD: -0.58, 95% CI: -0.84, -0.31, I2 = 66.3%) levels after surgery compared with before the surgery. Overall, bariatric surgery significantly reduced the levels of valine, leucine, and isoleucine compared with before the surgery. Further large-scale and homogenous trials are needed to better discern the generalizability of our findings.

Prognostic value of leucine/phenylalanine ratio as an amino acid profile of heart failure.

Heart failure (HF) causes a hypercatabolic state that enhances the catabolic activity of branched-chain amino acids (BCAA; leucine, isoleucine, and valine) in the heart and skeletal muscles and reduces protein synthesis in the liver. Consequently, free plasma aromatic amino acids (AAA, tyrosine and phenylalanine) are increased. To date, we have reported the prognostic value of the BCAA/AAA ratio (Fischer's ratio) in patients with HF. However, the leucine/phenylalanine ratio, which is a simpler index than the Fischer's ratio, has not been examined. Therefore, the prognostic value of the leucine/phenylalanine ratio in patients with HF was investigated. Overall 157 consecutive patients hospitalized for worsening HF (81 men, median age 78 years) were enrolled in the study. Plasma amino acid levels were measured when the patients were stabilized at discharge. Cardiac events were defined as a composite of cardiac death and hospitalization for worsening HF. A total of 46 cardiac events occurred during the median follow-up period of 238 (interquartile range 93-365) days. The median leucine/phenylalanine ratio was significantly lower in patients with cardiac events than in those without cardiac events (1.4 vs. 1.8, P < 0.001). The best cutoff value of the leucine/phenylalanine ratio was determined as 1.7 in the receiver operating characteristic (ROC) curve for cardiac events. Following a Kaplan-Meier survival analysis, the low group (leucine/phenylalanine ratio < 1.7, n = 72) had more cardiac events than the high group (leucine/phenylalanine ratio ≥ 1.7, n = 85) (log-rank, P < 0.001). Multivariate Cox proportional hazards regression analysis showed that the leucine/phenylalanine ratio was an independent predictor of cardiac events. Furthermore, on comparing the prognostic values for cardiac events based on ROC curves of leucine levels, BCAA levels, Fischer's ratio, and leucine/phenylalanine ratio, the leucine/phenylalanine ratio was the most accurate in predicting future cardiac events (area under the curve 0.763,; sensitivity 0.783,; specificity 0.676,; P < 0.001). The leucine/phenylalanine ratio could be a useful predictor of future cardiac events in patients with HF, reflecting an imbalance in amino acid metabolism.

Different Blood Metabolomics Profiles in Infants Consuming a Meat- or Dairy-Based Complementary Diet.

BACKGROUND: Research is limited in evaluating the mechanisms responsible for infant growth in response to different protein-rich foods; Methods: Targeted and untargeted metabolomics analysis were conducted on serum samples collected from an infant controlled-feeding trial that participants consumed a meat- vs. dairy-based complementary diet from 5 to 12 months of age, and followed up at 24 months. RESULTS: Isoleucine, valine, phenylalanine increased and threonine decreased over time among all participants; Although none of the individual essential amino acids had a significant impact on changes in growth Z scores from 5 to 12 months, principal component heavily weighted by BCAAs (leucine, isoleucine, valine) and phenylalanine had a positive association with changes in length-for-age Z score from 5 to 12 months. Concentrations of acylcarnitine-C4, acylcarnitine-C5 and acylcarnitine-C5:1 significantly increased over time with the dietary intervention, but none of the acylcarnitines were associated with infant growth Z scores. Quantitative trimethylamine N-oxide increased in the meat group from 5 to 12 months; Conclusions: Our findings suggest that increasing total protein intake by providing protein-rich complementary foods was associated with increased concentrations of certain essential amino acids and short-chain acyl-carnitines. The sources of protein-rich foods (e.g., meat vs. dairy) did not appear to differentially impact serum metabolites, and comprehensive mechanistic investigations are needed to identify other contributors or mediators of the diet-induced infant growth trajectories.

Maple syrup urine disease: Clinical outcomes, metabolic control, and genotypes in a screened population after four decades of newborn bloodspot screening in the Republic of Ireland.

Since 1972, 18 patients (10 females/8 males) have been detected by newborn bloodspot screening (NBS) with neonatal-onset maple syrup urine disease (MSUD) in Ireland. Patients were stratified into three clusters according to clinical outcome at the time of data collection, including developmental, clinical, and IQ data. A fourth cluster comprised of two early childhood deaths; a third patient died as an adult. We present neuroimaging and electroencephalography together with clinical and biochemical data. Incidence of MSUD (1972-2018) was 1 in 147 975. Overall good clinical outcomes were achieved with 15/18 patients alive and with essentially normal functioning (with only the lowest performing cluster lying beyond a single SD on their full scale intelligence quotient). Molecular genetic analysis revealed genotypes hitherto not reported, including a possible digenic inheritance state for the BCKDHA and DBT genes in one family. Treatment has been based on early implementation of emergency treatment, diet, close monitoring, and even dialysis in the setting of acute metabolic decompensation. A plasma leucine ≥400 µmol/L (outside therapeutic range) was more frequently observed in infancy or during adolescence, possibly due to infections, hormonal changes, or noncompliance. Children require careful management during metabolic decompensations in early childhood, and this represented a key risk period in our cohort. A high level of metabolic control can be achieved through diet with early implementation of a "sick day" regime and, in some cases, dialysis as a rescue therapy. The Irish cohort, despite largely classical phenotypes, achieved good outcomes in the NBS era, underlining the importance of early diagnosis and skilled multidisciplinary team management.

Associations between Plasma Branched Chain Amino Acids and Health Biomarkers in Response to Resistance Exercise Training Across Age.

Leucine, isoleucine and valine (i.e., the branched chain amino acids, BCAA) play a key role in the support and regulation of tissue protein regulation and also as energy substrates. However, positive relationships exist between elevated levels of BCAA and insulin resistance (IR). Thus, we sought to investigate the links between fasting plasma BCAA following a progressive resistance exercise training (RET) programme, an intervention known to improve metabolic health. Fasting plasma BCAA were quantified in adults (young: 18-28 y, n = 8; middle-aged: 45-55 y, n = 9; older: 65-75 y, n = 15; BMI: 23-28 kg/m2, both males and females (~50:50), in a cross-sectional, intervention study. Participants underwent 20-weeks whole-body RET. Measurements of body composition, muscle strength (1-RM) and metabolic health biomarkers (e.g., HOMA-IR) were made pre- and post-RET. BCAA concentrations were determined by gas-chromatography mass spectrometry (GC-MS). No associations were observed across age with BCAA; however, RET elicited (p < 0.05) increases in plasma BCAA (all age-groups), while HOMA-IR scores reduced (p < 0.05) following RET. After RET, positive correlations in lean body mass (p = 0.007) and strength gains (p = 0.001) with fasting BCAA levels were observed. Elevated BCAA are not a robust marker of ageing nor IR in those with a healthy BMI; rather, despite decreasing IR, RET was associated with increased BCAA.

Circulating branched-chain amino acids and long-term risk of obesity-related cancers in women.

Obesity is a risk factor for > 13 cancer sites, although it is unknown whether there is a common mechanism across sites. Evidence suggests a role for impaired branched-chain amino acid (BCAAs; isoleucine, leucine, valine) metabolism in obesity, insulin resistance, and immunity; thus, we hypothesized circulating BCAAs may be associated with incident obesity-related cancers. We analyzed participants in the prospective Women's Health Study without a history of cancer at baseline blood collection (N = 26,711, mean age = 54.6 years [SD = 7.1]). BCAAs were quantified via NMR spectroscopy, log-transformed, and standardized. We used Cox proportional regression models adjusted for age, race, smoking, diet, alcohol, physical activity, menopausal hormone use, Body Mass Index (BMI), diabetes, and other risk factors. The endpoint was a composite of obesity-related cancers, defined per the International Agency for Research on Cancer 2016 report, over a median 24 years follow-up. Baseline BMI ≥ 30 kg/m2 compared with BMI 18.5-25.0 kg/m2 was associated with 23% greater risk of obesity-related cancers (n = 2751 events; multivariable HR 1.23, 95% CI 1.11-1.37). However, BCAAs were not associated with obesity-related cancers (multivariable HR per SD = 1.01 [0.97-1.05]). Results for individual BCAA metabolites suggested a modest association for leucine with obesity-related cancers (1.04 [1.00-1.08]), and no association for isoleucine or valine (0.99 [0.95-1.03] and 1.00 [0.96-1.04], respectively). Exploratory analyses of BCAAs with individual sites included positive associations between leucine and postmenopausal breast cancer, and isoleucine with pancreatic cancer. Total circulating BCAAs were unrelated to obesity-related cancer incidence although an association was observed for leucine with incident obesity-related cancer.

A Thorough QT Study of the Combination Glecaprevir + Pibrentasvir on Cardiac Repolarization in Healthy Subjects.

PURPOSE: Fixed-dose combination glecaprevir (GLE) 300 mg + pibrentasvir (PIB) 120 mg is an orally administered once daily antiviral regimen approved for the treatment of hepatitis C virus (HCV) infection. The objective of this study was to evaluate the potential for cardiac repolarization following GLE + PIB administration in healthy adults. METHODS: This placebo- and active-controlled, randomized, single-dose, 4-period, 4-sequence crossover study enrolled 48 healthy subjects. The doses of GLE 400 mg + PIB 120 mg were selected to provide exposures comparable to those with the doses that are therapeutic in the HCV-infected population, GLE 300 mg + PIB 120 mg. The doses of GLE 600 mg + PIB 240 mg were selected to provide supratherapeutic exposures without exceeding the exposures of the GLE + PIB maximal tolerated doses. Moxifloxacin 400 mg (active control/open label) was used for confirming the sensitivity of the ECG assay in detecting QTc prolongation. Time-matched plasma concentrations and triplicate ECGs were obtained on treatment days -1 and 1. The primary end point was time-matched, placebo-corrected, baseline-adjusted Fridericia-corrected QT interval (ΔΔQTcF). Pharmacokinetic-pharmacodynamic analyses characterized the relationship between GLE and PIB plasma concentrations and ΔΔQTcF using a linear regression model and linear mixed-effects model. Findings from categorical analyses of ECG-interval data were also summarized. Tolerability was evaluated through adverse-events monitoring, physical examination including vital sign measurements, ECGs, and laboratory tests. FINDINGS: A total of 48 subjects (22 women [46%], 26 men [54%]), were enrolled in the study, and 47 subjects completed all 4 periods. None of the subjects had a change from baseline in QTcF interval of >30 msec or an absolute QTcF interval of >450 msec. Peak ΔΔQTcF values observed at 5 h postdose (Tmax) were 2.9 msec (upper 95% confidence limit, 4.9 msec) with the therapeutic dose and 3.1 msec (upper 95% confidence limit, 5.1 msec) with the supratherapeutic dose, with both upper 95% confidence limits well below the 10-msec threshold. Assay sensitivity was confirmed by peak ΔΔQTcF in the positive control (12.8 ms at 2 h postdose). No statistically significant GLE or PIB concentration-dependent effects on ΔΔQTcF were observed. Headache and skin irritation from ECG electrodes were the most commonly reported AEs. No clinically significant vital sign measurements, ECG findings, or laboratory measurements were observed. There were no patterns of T- and U-wave morphologic abnormalities. IMPLICATIONS: The fixed-dose combination regimen of GLE/PIB does not prolong the QTc interval. ClinicalTrials.gov identifier.