Betaine and secondary events in an acute coronary syndrome cohort

Targeted metabolomic profiling of acute ST-segment elevation myocardial infarction

Myocardial infarction is a major cause of morbidity and mortality worldwide. Metabolomic investigations may be useful for understanding the pathogenesis of ST-segment elevation myocardial infarction (STEMI). STEMI patients were comprehensively examined via targeted metabolomic profiling, machine learning and weighted correlation network analysis. A total of 195 subjects, including 68 STEMI patients, 84 patients with stable angina pectoris (SAP) and 43 non-CVD patients, were enrolled in the study. Metabolomic profiling involving the quantitative analysis of 87 endogenous metabolites in plasma was conducted. This study is the first to perform targeted metabolomic profiling in patients with STEMI. We identified 36 significantly altered metabolites in STEMI patients. Increased levels of four amino acids, eight acylcarnitines, six metabolites of the NO-urea cycle and neurotransmitters, and three intermediates of tryptophan metabolism were detected. The following metabolites exhibited decreased levels: six amino acids, three acylcarnitines, three components of the NO-urea cycle and neurotransmitters, and three intermediates of tryptophan metabolism. We found that the significant changes in tryptophan metabolism observed in STEMI patients-the increase in anthranilic acid and tryptophol and decrease in xanthurenic acid and 3-OH-kynurenine-may play important roles in STEMI pathogenesis. On the basis of the differences in the constructed weighted correlation networks, new significant metabolite ratios were identified. Among the 22 significantly altered metabolite ratios identified, 13 were between STEMI patients and non-CVD patients, and 17 were between STEMI patients and SAP patients. Seven of these ratios were common to both comparisons (STEMI patients vs. non-CVD patients and STEMI patients vs. SAP patients). Additionally, two ratios were consistently observed among the STEMI, SAP and non-CVD groups (anthranilic acid: aspartic acid and GSG (glutamine: serine + glycine)). These findings provide new insight into the diagnosis and pathogenesis of STEMI.

The gut microbiota derived metabolite trimethylamine N-oxide: Its important role in cancer and other diseases

An expanding body of research indicates a correlation between the gut microbiota and various diseases. Metabolites produced by the gut microbiota act as mediators between the gut microbiota and the host, interacting with multiple systems in the human body to regulate physiological or pathological functions. However, further investigation is still required to elucidate the underlying mechanisms. One such metabolite involved in choline metabolism by gut microbes is trimethylamine (TMA), which can traverse the intestinal epithelial barrier and enter the bloodstream, ultimately reaching the liver where it undergoes oxidation catalyzed by flavin-containing monooxygenase 3 (FMO3) to form trimethylamine N-oxide (TMAO). While some TMAO is eliminated through renal excretion, remaining amounts circulate in the bloodstream, leading to systemic inflammation, endoplasmic reticulum (ER) stress, mitochondrial stress, and disruption of normal physiological functions in humans. As a representative microbial metabolite originating from the gut, TMAO has significant potential both as a biomarker for monitoring disease occurrence and progression and for tailoring personalized treatment strategies for patients. This review provides an extensive overview of TMAO sources and its metabolism in human blood, as well as its impact on several major human diseases. Additionally, we explore the latest research areas related to TMAO along with future directions.

The Role of Gut Microbiota and Its Metabolites in Patients with Heart Failure

Heart failure (HF) is a significant health concern; early detection and prevention are crucial. Recent studies suggest that the gut microbiota and its metabolites may influence HF development and risk factors. We explored this relationship by examining changes in gut microbiota composition and metabolite levels in HF patients. HF patients often exhibit decreased alpha and beta diversity compared to controls, suggesting lower bacterial richness and community variation. Changes in specific bacterial phyla were observed, with decreases in Firmicutes (e.g., Ruminococcus) and Bacteroidetes (e.g., Prevotella) and increases in Proteobacteria (e.g., Escherichia, Shigella, and Klebsiella) and Actinobacteria. Gut-microbiota-related metabolites have been identified, potentially affecting various body systems, including the cardiovascular system. Among these are short-chain fatty acids (SCFAs), betaine, trimethylamine N-oxide (TMAO), phenylalanine, tryptophan-kynurenine, and phenylacetylgutamine (PAGIn). Although SCFAs positively affect our organisms, patients with HF have been observed to experience a decline in bacteria responsible for producing these chemical compounds. There have been indications of possible links between betaine, TMAO, phenylalanine, tryptophan-kynurenine, PAGIn, and heart failure. TMAO and phenylalanine, in particular, show promise as potential prognostic factors. However, their clinical significance has not yet been thoroughly evaluated and requires further investigation.

Association of Gut Microbiota-Related Metabolites and Type 2 Diabetes in Two Puerto Rican Cohorts

(1) Aims: Gut microbiota metabolites may play integral roles in human metabolism and disease progression. However, evidence for associations between metabolites and cardiometabolic risk factors is sparse, especially in high-risk Hispanic populations. We aimed to evaluate the cross-sectional and longitudinal relationships between gut microbiota related metabolites and measures of glycemia, dyslipidemia, adiposity, and incident type 2 diabetes in two Hispanic observational cohorts. (2) Methods: We included data from 670 participants of the Boston Puerto Rican Health Study (BPRHS) and 999 participants of the San Juan Overweight Adult Longitudinal Study (SOALS). Questionnaires and clinical examinations were conducted over 3 years of follow-up for SOALS and 6 years of follow-up for BPRHS. Plasma metabolites, including L-carnitine, betaine, choline, and trimethylamine N-oxide (TMAO), were measured at baseline in both studies. We used multivariable linear models to evaluate the associations between metabolites and cardiometabolic risk factors and multivariable logistic and Poisson regressions to assess associations with prevalent and incident type 2 diabetes, adjusted for potential confounding factors. Cohort-specific analyses were combined using a fixed-effects meta-analysis. (3) Results: Higher plasma betaine was prospectively associated with lower fasting glucose [-0.97 mg/dL (95% CI: -1.59, -0.34), p = 0.002], lower HbA1c [-0.02% (95% CI: -0.04, -0.01), p = 0.01], lower HOMA-IR [-0.14 (95% CI: -0.23, -0.05), p = 0.003], and lower fasting insulin [-0.27 mcU/mL (95% CI: -0.51, -0.03), p = 0.02]. Betaine was also associated with a 22% lower incidence of type 2 diabetes (IRR: 0.78, 95% CI: 0.65, 0.95). L-carnitine was associated with lower fasting glucose [-0.68 mg/dL (95% CI: -1.29, -0.07), p = 0.03] and lower HbA1c at follow-up [-0.03% (95% CI: -0.05, -0.01), p < 0.001], while TMAO was associated with higher fasting glucose [0.83 mg/dL (95% CI: 0.22, 1.44), p = 0.01] and higher triglycerides [3.52 mg/dL (95% CI: 1.83, 5.20), p < 0.0001]. Neither choline nor TMAO were associated with incident type 2 diabetes. (4) Conclusions: Higher plasma betaine showed consistent associations with a lower risk of glycemia, insulinemia, and type 2 diabetes. However, TMAO, a metabolite of betaine, was associated with higher glucose and lipid concentrations. These observations demonstrate the importance of gut microbiota metabolites for human cardiometabolic health.

Metabolomics Profiling Predicts Ventricular Arrhythmia in Patients with an Implantable Cardioverter Defibrillator

Implantable cardioverter defibrillators (ICDs) reduce sudden cardiac death (SCD) when patients experience life-threatening ventricular arrhythmias (LTVA). However, current strategies determining ICD patient selection and risk stratification are inefficient. We used metabolomics to assess whether dysregulated metabolites are associated with LTVA and identify potential biomarkers. Baseline plasma samples were collected from 72 patients receiving ICDs. Over a median follow-up of 524.0 days (range 239.0-705.5), LTVA occurred in 23 (31.9%) patients (22 effective ICD treatments and 1 SCD). After confounding risk factors adjustment for age, smoking, secondary prevention, and creatine kinase MB, 23 metabolites were significantly associated with LTVA. Pathway analysis revealed LTVA associations with disrupted metabolism of glycine, serine, threonine, and branched chain amino acids. Pathway enrichment analysis identified a panel of 6 metabolites that potentially predicted LTVA, with an area under the receiver operating characteristic curve of 0.8. Future studies are necessary on biological mechanisms and potential clinical use.

Targeted Plasma Metabolomics Reveals Association of Acute Myocardial Infarction Risk with the Dynamic Balance between Trimethylamine-N-oxide, Betaine, and Choline

The relationship between trimethylamine-N-oxide (TMAO), betaine, and choline with acute myocardial infarction (AMI) end point remains unclear. We analyzed plasma TMAO, betaine, and choline concentrations in AMI cases and non-AMI community-dwelling controls by LC-MS/MS to understand how the balance between these metabolites helps to reduce AMI risk. Results showed that the odds ratio (OR) for the highest versus lowest quartiles of betaine was 0.30 (95% CI, 0.10-0.82) after adjustment for AMI risk factors, and the unadjusted OR for quartile 3 versus quartile 1 of TMAO was 2.47 (95% CI, 1.02-6.17) (p < 0.05). The study populations with "high betaine + low TMAO" had a significant protective effect concerning AMI with a multivariable-adjusted OR of 0.20 (95% CI, 0.07-0.55) (p < 0.01). Multivariate linear regression showed that the chronological age was correlated with TMAO concentrations among AMI patients (95% CI, 0.05-3.24, p < 0.01) but not among the controls. This implies a further potential interplay between age and metabolite combination─AMI risk association.

Association of choline and betaine with the risk of cardiovascular disease and all-cause mortality: Meta-analysis

BACKGROUND

This study aimed to systematically evaluate the role of circulating levels of choline and betaine in the risk of cardiovascular disease (CVD) and all-cause mortality by comprehensively reviewing observational studies.

METHODS

This study was conducted according to PRISMA 2020 statement. Six electronic databases, including PubMed, Embase and China National Knowledge Infrastructure (CNKI), were searched for cohort studies and derivative research design types (nested case-control and case-cohort studies) from the date of inception to March 2022. We pooled relative risk (RR) and 95% confidence interval (CI) of the highest versus lowest category and per SD of circulating choline and betaine concentrations in relation to the risk of CVD and all-cause mortality.

RESULTS

In the meta-analysis, 17 studies with a total of 33,009 participants were included. Random-effects model results showed that highest versus lowest quantile of circulating choline concentrations were associated with the risk of CVD (RR = 1.29, 95% CI: 1.04-1.61) and all-cause mortality (RR = 1.62, 95% CI: 1.12-2.36). We also observed the risk of CVD were increased 13% (5%-22%) with per SD increment. Furthermore, highest versus lowest quantile of circulating betaine concentrations were not associated with the risk of CVD (RR = 1.07, 95% CI: 0.92-1.24) and all-cause mortality (RR = 1.39, 95% CI: 0.96-2.01). However, the risk of CVD was increased 14% (5%-23%) with per SD increment.

CONCLUSIONS

Higher levels of circulating choline were associated with a higher risk of CVD and all-cause mortality.

Combined Metabolipidomic and Machine Learning Approach in a Rat Model of Stroke Reveals a Deleterious Impact of Brain Injury on Heart Metabolism

Cardiac complications are frequently found following a stroke in humans whose pathophysiological mechanism remains poorly understood. We used machine learning to analyse a large set of data from a metabolipidomic study assaying 630 metabolites in a rat stroke model to investigate metabolic changes affecting the heart within 72 h after a stroke. Twelve rats undergoing a stroke and 28 rats undergoing the sham procedure were investigated. A plasmatic signature consistent with the literature with notable lipid metabolism remodelling was identified. The post-stroke heart showed a discriminant metabolic signature, in comparison to the sham controls, involving increased collagen turnover, increased arginase activity with decreased nitric oxide synthase activity as well as an altered amino acid metabolism (including serine, asparagine, lysine and glycine). In conclusion, these results demonstrate that brain injury induces a metabolic remodelling in the heart potentially involved in the pathophysiology of stroke heart syndrome.

Healthy Nordic diet and associations with plasma concentrations of metabolites in the choline oxidation pathway: a cross-sectional study from Northern Sweden

BACKGROUND

The choline oxidation pathway and metabolites involved have been linked to diseases including cardiovascular disease, type 2 diabetes and cancer. A healthy Nordic diet is a recently defined dietary pattern associated with decreased risk for these diseases. Our aim was to explore associations between adherence to a healthy Nordic diet and plasma concentrations of metabolites of the choline oxidation pathway.

METHODS

The Healthy Nordic Food Index (HNFI) and Baltic Sea Diet Score (BSDS) were applied to cross-sectional data (n = 969) from the Västerbotten Intervention Programme in Northern Sweden to score adherence to a healthy Nordic diet. Data included responses to a dietary questionnaire and blood sample analyses (1991-2008). Associations of diet scores with plasma concentrations of metabolites of the choline oxidation pathway and total homocysteine (tHcy), seven metabolites in total, were evaluated with linear regression, adjusting for age, BMI, education and physical activity.

RESULTS

HNFI scores showed linear relationships with plasma choline (β = 0.11), betaine (β = 0.46), serine (β = 0.98) and tHcy (β =  - 0.38), and BSDS scores with betaine (β = 0.13) and tHcy (β =  - 0.13); unstandardized beta coefficients, all significant at P < 0.05. The regression models predicted changes in plasma metabolite concentrations (± 1 SD changes in diet score) in the range of 1-5% for choline, betaine, serine and tHcy. No other statistically significant associations were observed.

CONCLUSIONS

A healthy Nordic diet was associated with plasma concentrations of several metabolites of the choline oxidation pathway. Although relationships were statistically significant, effect sizes were moderate. Further research is warranted to explore the underlying mechanisms and associations with health outcomes.

Associations of serum betaine with blood pressure and hypertension incidence in middle-aged and older adults: a prospective cohort study

The impact of betaine on the development of hypertension remains unclear, and prospective data are sparse. We aimed to investigate the association of serum betaine with repeated measurements of blood pressure (BP) and hypertension incidence. This study was based on the Guangzhou Nutrition and Health Study (GNHS), a community-based prospective cohort study in China. Baseline serum betaine was measured by high-performance liquid chromatography-tandem mass spectrometry. BP and hypertension status were assessed at the baseline and 3-year intervals. Linear mixed-effects models (LMEMs) were used to analyze the longitudinal association of serum betaine with BP (n = 1996). Cox proportional hazard models were used to evaluate the association of baseline serum betaine with hypertension incidence (n = 1339). LMEMs showed that compared with the lowest quartile group, the higher quartile groups had lower systolic blood pressure (SBP), diastolic blood pressure (DBP) and pulse pressure (all P-trend < 0.05). Each standard deviation (16.3 μmol L^-1) increase in serum betaine was associated with -0.92 (-1.52, -0.32) mmHg of SBP, -0.49 (-0.84, -0.13) mmHg of DBP and -0.43 (-0.81, -0.05) mmHg of pulse pressure. During a median follow-up of 9.2 years, 371 incident cases of hypertension were identified. Serum betaine was associated with lower risk of hypertension only when comparing the third quartile level with the lowest quartile (HR, 0.74; 95% CI, 0.56-0.99). A nonlinear association between serum betaine and the risk of hypertension was found (P-nonlinear = 0.040). A higher serum betaine level was associated with lower risk of hypertension below 54.5 μmol L^-1. Our findings suggested that higher serum betaine was associated with favorable blood pressure in middle-aged and older Chinese adults. Higher concentrations of serum betaine were related to lower hypertension risk in people with relatively low serum betaine concentrations.

Plasma trimethylamine-N-oxide, its precursors and risk of cardiovascular events in patients with acute coronary syndrome: Mediating effects of renal function

Aims

To examine associations of the gut microbial metabolite trimethylamine-N-oxide (TMAO) and its precursors with risk of cardiovascular events in acute coronary syndrome (ACS), and determine whether these associations were mediated by renal function.

Methods

In this prospective cohort study, we included 309 patients with ACS. During a mean follow-up of 6.7 years, 131 patients developed major adverse cardiovascular events (MACE) (myocardial infarction, hospitalization for heart failure, and all-cause mortality). Plasma concentrations of TMAO, trimethylamine (TMA), choline, betaine, dimethylglycine and L-carnitine were profiled by liquid chromatography tandem mass spectrometry. Hazard ratios were estimated with multivariable Cox regression models. The mediating role of estimated glomerular filtration rate (eGFR) was tested under a counterfactual framework.

Results

After adjustment for traditional cardiovascular risk factors and medications, participants in the highest tertile vs. the lowest tertile of baseline TMAO and dimethylglycine concentrations had a higher risk of MACE [(HR: 1.83; 95% CI: 1.08, 3.09) and (HR: 2.26; 95% CI: 1.17, 3.99), respectively]. However, with regards to TMAO these associations were no longer significant, whereas for dimethylglycine, the associations were attenuated after additional adjustment for eGFR. eGFR mediated the associations of TMAO (58%) and dimethylglycine (32%) with MACE incidence. The associations between dimethylglycine and incident MACE were confirmed in an internal validation. No significant associations were found for TMA, choline, betaine and L-carnitine.

Conclusion

These findings suggest that renal function may be a key mediator in the association of plasma TMAO with the development of cardiovascular events after ACS. The present findings also support a role of dimethylglycine in the pathogenesis of MACE, which may be mediated, at least partially, by renal function.

Serum Homocysteine and Vascular Calcification: Advances in Mechanisms, Related Diseases, and Nutrition

Identifying and preventing modifiable risk factors for cardiovascular disease is very important. Vascular calcification has been studied clinically as an asymptomatic preclinical marker of atherosclerosis and a risk factor for cardio-cerebrovascular disease. It is known that higher homocysteine levels are associated with calcified plaques and the higher the homocysteine level, the higher the prevalence and progression of vascular calcification. Homocysteine is a byproduct of methionine metabolism and is generally maintained at a physiological level. Moreover, it may increase if the patient has a genetic deficiency of metabolic enzymes, nutritional deficiencies of related cofactors (vitamins), chronic diseases, or a poor lifestyle. Homocysteine is an oxidative stress factor that can lead to calcified plaques and trigger vascular inflammation. Hyperhomocysteinemia causes endothelial dysfunction, transdifferentiation of vascular smooth muscle cells, and the induction of apoptosis. As a result of transdifferentiation and cell apoptosis, hydroxyapatite accumulates in the walls of blood vessels. Several studies have reported on the mechanisms of multiple cellular signaling pathways that cause inflammation and calcification in blood vessels. Therefore, in this review, we take a closer look at understanding the clinical consequences of hyperhomocysteinemia and apply clinical approaches to reduce its prevalence.

Implications of trimethylamine N-oxide (TMAO) and Betaine in Human Health: Beyond Being Osmoprotective Compounds

Osmolytes are naturally occurring small molecular weight organic molecules, which are accumulated in large amounts in all life forms to maintain the stability of cellular proteins and hence preserve their functions during adverse environmental conditions. Trimethylamine N-oxide (TMAO) and N,N,N-trimethylglycine (betaine) are methylamine osmolytes that have been extensively studied for their diverse roles in humans and have demonstrated opposing relations with human health. These osmolytes are obtained from food and synthesized endogenously using dietary constituents like choline and carnitine. Especially, gut microbiota plays a vital role in TMAO synthesis and contributes significantly to plasma TMAO levels. The elevated plasma TMAO has been reported to be correlated with the pathogenesis of numerous human diseases, including cardiovascular disease, heart failure, kidney diseases, metabolic syndrome, etc.; Hence, TMAO has been recognized as a novel biomarker for the detection/prediction of several human diseases. In contrast, betaine acts as a methyl donor in one-carbon metabolism, maintains cellular S-adenosylmethionine levels, and protects the cells from the harmful effects of increased plasma homocysteine. Betaine also demonstrates antioxidant and anti-inflammatory activities and has a promising therapeutic value in several human diseases, including homocystinuria and fatty liver disease. The present review examines the multifarious functions of TMAO and betaine with possible molecular mechanisms towards a better understanding of their emerging and diverging functions with probable implications in the prevention, diagnosis, and treatment of human diseases.

Guanidinoacetic acid provides superior cardioprotection to its combined use with betaine and (or) creatine in HIIT-trained rats

This study aimed to determine how guanidinoacetic acid (GAA) or its combined administration with betaine (B) or creatine (C) influences the cardiac function, morphometric parameters, and redox status of rats subjected to high-intensity interval training (HIIT). This research was conducted on male Wistar albino rats exposed to HIIT for 4 weeks. The animals were randomly divided into five groups: HIIT, HIIT + GAA, HIIT + GAA + C, HIIT + GAA + B, and HIIT + GAA + C + B. After completing the training protocol, GAA (300 mg/kg), C (280 mg/kg), and B (300 mg/kg) were applied daily per os for 4 weeks. GAA supplementation in combination with HIIT significantly decreased the level of both systemic and cardiac prooxidants ( O 2 - , H₂O₂, NO 2 - , and thiobarbituric acid reactive substances) compared with nontreated HIIT (p < 0.05). Also, GAA treatment led to an increase in glutathione and superoxide dismutase levels. None of the treatment regimens altered cardiac function. A larger degree of cardiomyocyte hypertrophy was observed in the HIIT + GAA group, which was reflected through an increase of the cross-sectional area of 27% (p < 0.05) and that of the left ventricle wall thickness of 27% (p < 0.05). Since we showed that GAA in combination with HIIT may ameliorate oxidative stress and does not alter cardiac function, the present study is a basis for future research exploring the mechanisms of cardioprotection induced by this supplement in an HIIT scenario.

High Betaine and Dynamic Increase of Betaine Levels Are Both Associated With Poor Prognosis of Patients With Pulmonary Hypertension

Background and Objective

The association between plasma betaine levels and cardiovascular diseases (CVDs) has been revealed except for pulmonary hypertension (PH). In this study, we aimed to explore the role of betaine in patients with PH.

Methods

Inpatients with PH at Fuwai Hospital were enrolled after excluding relative comorbidities. Each patient received at least one follow-up through a clinical visit, and the fasting blood was obtained both at the first and second hospitalization for betaine detection. The primary endpoint was defined as composite outcome events and the mean duration was 14.3 (6.9, 21.3) months. The associations of betaine and changes of betaine (Δbetaine) with disease severity and prognosis were explored.

Results

Finally, a total of 216 patients with PH were included and the medians for betaine plasma levels in the total patients group, low betaine, and high betaine groups were 49.8 (39.0, 68.3) μM, 39.0 (33.5, 44.7) μM, and 68.1 (57.8, 88.7) μM, respectively. High betaine was associated with poor World Health Organization Functional Class (WHO-FC), increased N-terminal pro-brain natriuretic peptide (NT-proBNP), low tricuspid annular plane systolic excursion (TAPSE), and cardiac output index even after adjusting for confounders. Patients with high betaine were over twice the risk to receive the poor prognosis than those with a low level [hazard ratio (HR) = 2.080, (95% CI: 1.033–4.188)]. Moreover, the decrease of betaine level after further treatment was positively correlated to ΔNT-proBNP indicating Δbetaine might be an effector of disease severity, and dynamic increase of betaine was also associated with poor prognosis in PH.

Conclusion

Betaine was associated with disease severity and might be an effector in PH. Patients with increased levels or with dynamic rise of betaine heralded a poor prognosis.

Effects of Gut Microbiota and Metabolites on Heart Failure and Its Risk Factors: A Two-Sample Mendelian Randomization Study

Introduction

Previous observational studies have indicated that gut microbiota and metabolites may contribute to heart failure and its risk factors. However, with the limitation of reverse causality and confounder in observational studies, such relationship remains unclear. This study aims to reveal the causal effect of gut microbiota and metabolites on heart failure and its risk factors.

Methods

This study collected summary statistics regarding gut microbiota and metabolites, heart failure, diabetes, hypertension, chronic kidney disease, myocardial infarction, atrial fibrillation, hypertrophic cardiomyopathy, dilated cardiomyopathy, coronary heart disease, valvular heart disease, and myocarditis. Two-sample Mendelian randomization analysis was performed using MR-Egger, inverse variance weighted (IVW), MR-PRESSO, maximum likelihood, and weighted median.

Results

Results from gene prediction showed that among all gut microbiota, candida, shigella, and campylobacter were not associated with higher incidence of heart failure. However, genetic prediction suggested that for every 1 unit increase in shigella concentration, the relative risk increased by 38.1% for myocarditis and 13.3% for hypertrophic cardiomyopathy. Besides, for every 1 unit increased in candida concentration, the relative risk of chronic kidney disease increased by 7.1%. As for intestinal metabolites, genetic prediction results suggested that for every 1 unit increase in betaine, the relative risk of heart failure and myocardial infarction increased by 1.4% and 1.7%, separately.

Conclusions

This study suggested new evidence of the relationship between gut microbiota and heart failure and its risk factors, which may shed light on designing microbiome- and microbiome-dependent metabolite interventions on heart failure and its risk factors in clinical trials in the future.

Osmoregulatory Role of Betaine and Betaine/γ-Aminobutyric Acid Transporter 1 in Post-Traumatic Syringomyelia

Syringomyelia (SM) is primarily characterized by the formation of a fluid-filled cyst that forms in the parenchyma of the spinal cord following injury or other pathology. Recent omics studies in animal models have identified dysregulation of solute carriers, channels, transporters, and small molecules associated with osmolyte regulation during syrinx formation/expansion in the spinal cord. However, their connections to syringomyelia etiology are poorly understood. In this study, the biological functions of the potent osmolyte betaine and its associated solute carrier betaine/γ-aminobutyric acid (GABA) transporter 1 (BGT1) were studied in SM. First, a rat post-traumatic SM model was used to demonstrate that the BGT1 was primarily expressed in astrocytes in the vicinity of syrinxes. In an in vitro system, we found that astrocytes uptake betaine through BGT1 to regulate cell size under hypertonic conditions. Treatment with BGT1 inhibitors, especially NNC 05-2090, demonstrated midhigh micromolar range potency in vitro that reversed the osmoprotective effects of betaine. Finally, the specificity of these BGT1 inhibitors in the CNS was demonstrated in vivo, suggesting feasibility for targeting betaine transport in SM. In summary, these data provide an enhanced understanding of the role of betaine and its associated solute carrier BGT1 in cell osmoregulation and implicates the active role of betaine and BGT1 in syringomyelia progression.

Plasma choline and betaine and risks of cardiovascular events and recurrent stroke after ischemic stroke

BACKGROUND

Choline and betaine have been suggested to play a pivotal role in neurotransmitter synthesis, cell membrane integrity, and methyl-group metabolism, exerting neuroprotective effects in patients with various neurological disorders. However, population-based evidence on choline and betaine with subsequent cardiovascular events after stroke is rare.

OBJECTIVES

We aimed to prospectively investigate the relationships of circulating choline and betaine with cardiovascular events and recurrent stroke in patients with ischemic stroke.

METHODS

We performed a nested case-control study within the China Antihypertensive Trial in Acute Ischemic Stroke. A total of 323 cardiovascular events (including 264 recurrent strokes) and 323 controls (free of recurrent cardiovascular events) matched for age (±1 y), sex, and treatment group were included. The primary endpoint was a composite of cardiovascular events after ischemic stroke. Plasma choline and betaine were measured at baseline by ultra-high-performance LC-MS/MS. Conditional logistic regression models were applied, and discrimination, reclassification, and calibration of models with choline pathway metabolites were evaluated.

RESULTS

Plasma choline and betaine were inversely associated with cardiovascular events and recurrent stroke after ischemic stroke. Specifically, in fully adjusted models, each additional SD of choline and betaine was associated with 35% (95% CI: 20%-48%) and 30% (95% CI: 14%-43%) decreased risks of subsequent cardiovascular events, respectively, and 34% (95% CI: 16%-48%) and 29% (95% CI: 12%-43%) decreased risks of recurrent stroke, respectively. In addition, both choline and betaine offered substantial risk discrimination and reclassification improvement for cardiovascular events and recurrent stroke beyond traditional risk factors, as evidenced by an increase in C statistics, the net reclassification index, and integrated discrimination improvement.

CONCLUSIONS

Plasma choline pathway metabolites, including choline and betaine, were associated with decreased risks of cardiovascular events and recurrent stroke and provided incremental value in risk discrimination and stratification in patients with ischemic stroke. This nested case-control study was based on the China Antihypertensive Trial in Acute Ischemic Stroke, which is registered at clinicaltrials.gov as NCT01840072.

Choline Metabolism and Risk of Atrial Fibrillation and Heart Failure in the PREDIMED Study

BACKGROUND

Few studies have examined the associations of trimethylamine-N-oxide (TMAO) and its precursors (choline, betaine, dimethylglycine, and L-carnitine) with the risk of atrial fibrillation (AF) and heart failure (HF). This study sought to investigate these associations.

METHODS

Prospective associations of these metabolites with incident AF and HF were examined among participants at high cardiovascular risk in the PREDIMED study (PREvención con DIeta MEDiterránea) after follow-up for about 10 years. Two nested case-control studies were conducted, including 509 AF incident cases matched to 618 controls and 326 HF incident cases matched to 426 controls. Plasma levels of TMAO and its precursors were semi-quantitatively profiled with liquid chromatography tandem mass spectrometry. Odds ratios were estimated with multivariable conditional logistic regression models.

RESULTS

After adjustment for classical risk factors and accounting for multiple testing, participants in the highest quartile vs. the lowest quartile of baseline choline and betaine levels had a higher risk of AF [OR (95% CI): 1.85 (1.30-2.63) and 1.57 (1.09-2.24), respectively]. The corresponding OR for AF for extreme quartiles of dimethylglycine was 1.39 (0.99-1.96). One SD increase in log-transformed dimethylglycine was positively associated with AF risk (OR, 1.17; 1.03-1.33). The corresponding ORs for HF for extreme quartiles of choline, betaine, and dimethylglycine were 2.51 (1.57-4.03), 1.65 (1.00-2.71) and 1.65 (1.04-2.61), respectively. TMAO and L-carnitine levels were not associated with AF or HF.

CONCLUSIONS

Our findings support the role of the choline metabolic pathway in the pathogenesis of AF and HF.

Two methods for assessment of choline status in a randomized crossover study with varying dietary choline intake in people: isotope dilution MS of plasma and in vivo single-voxel magnetic resonance spectroscopy of liver

BACKGROUND

Choline deficiency has numerous negative health consequences; although the preponderance of the US population consumes less than the recommended Adequate Intake (AI), clinical assessment of choline status is difficult. Further, several pathways involved in primary metabolism of choline are estrogen-sensitive and the AI for premenopausal women is lower than that for men.

OBJECTIVES

We sought to determine whether in vivo magnetic resonance spectroscopy (MRS) of liver and/or isotope-dilution MS of plasma could identify biomarkers reflective of choline intake (preregistered primary outcomes 1 and 2, secondary outcome 1). Determination of whether biomarker concentrations showed sex dependence was a post hoc outcome. This substudy is a component of a larger project to identify a clinically useful biomarker panel for assessment of choline status.

METHODS

In a double-blind, randomized, crossover trial, people consumed 3 diets, representative of ∼100%, ∼50%, and ∼25% of the choline AI, for 2-wk periods. We measured the concentrations of choline and several metabolites using 1H single-voxel MRS of liver in vivo and using 2H-labeled isotope dilution MS of several choline metabolites in extracted plasma.

RESULTS

Plasma concentrations of 2H9-choline, unlabeled betaine, and 2H9-betaine, and the isotopic enrichment ratio (IER) of betaine showed highly significant between-diet effects (q < 0.0001), with unlabeled betaine concentration decreasing 32% from highest to lowest choline intake. Phosphatidylcholine IER was marginally significant (q = 0.03). Unlabeled phosphatidylcholine plasma concentrations did not show between-diet effects (q = 0.34). 2H9 (trimethyl)-phosphatidylcholine plasma concentrations (q = 0.07) and MRS-measured total soluble choline species liver concentrations (q = 0.07) showed evidence of between-diet effects but this was not statistically significant.

CONCLUSIONS

Although MRS is a more direct measure of choline status, variable spectral quality limited interpretation. MS analysis of plasma showed clear correlation of plasma betaine concentration, but not plasma phosphatidylcholine concentration, with dietary choline intake. Plasma betaine concentrations also correlate with sex status (premenopausal women, postmenopausal women, men).This trial was registered at clinicaltrials.gov as NCT03726671.

Comparing Levels of Metabolic Predictors of Coronary Heart Disease between Healthy Lean and Overweight Females

Screening for the metabolomic signature of coronary heart disease (CHD) before disease onset could help in early diagnosis and potentially disease prevention. In this study, the levels of 17 CHD metabolic biomarkers in apparently healthy overweight females were compared to lean counterparts, and their associations with conventional clinical risk factors were determined. Clinical and metabolic data from 200 apparently healthy non-obese Qatari females were collected from Qatar Biobank (discovery cohort). Logistic regression was used to assess the association between body mass index (BMI) groups and 17 CHD metabolic biomarkers, and receiver operating characteristic (ROC) analysis was used to evaluate the prognostic value of CHD metabolic biomarkers in overweight. Stepwise linear regression was performed to identify the classical risk factors associated with CHD metabolites differentiating the two BMI groups. Validation of the association of CHD metabolic biomarkers with BMI groups was performed in 107 subjects (replication cohort). Out of the tested CHD metabolic biomarkers, five were significantly different between lean and overweight females in the discovery cohort (AUC = 0.73). Among these, the association of mannose, asparagine, and linoleate with BMI groups was confirmed in the replication cohort (AUC = 0.97). Significant correlations between predictors of CHD in overweight healthy women and classical risk factors were observed, including serum levels of cholesterol, testosterone, triiodothyronine, thyroxine, creatinine, albumin, bilirubin, glucose, c-peptide, uric acid, calcium and chloride. Apparently, healthy overweight females exhibit significantly different levels of specific CHD metabolites compared to their lean counterparts, offering a prognostic potential with preventative value.

Plasma Metabolomic Profiles of Glycemic Index, Glycemic Load, and Carbohydrate Quality Index in the PREDIMED Study

BACKGROUND

The quality of carbohydrate consumed, assessed by the glycemic index (GI), glycemic load (GL), or carbohydrate quality index (CQI), affects the postprandial glycemic and insulinemic responses, which have been implicated in the etiology of several chronic diseases. However, it is unclear whether plasma metabolites involved in different biological pathways could provide functional insights into the role of carbohydrate quality indices in health.

OBJECTIVES

We aimed to identify plasma metabolomic profiles associated with dietary GI, GL, and CQI.

METHODS

The present study is a cross-sectional analysis of 1833 participants with overweight/obesity (mean age = 67 y) from 2 case-cohort studies nested within the PREDIMED (Prevención con Dieta Mediterránea) trial. Data extracted from validated FFQs were used to estimate the GI, GL, and CQI. Plasma concentrations of 385 metabolites were profiled with LC coupled to MS and associations of these metabolites with those indices were assessed with elastic net regression analyses.

RESULTS

A total of 58, 18, and 57 metabolites were selected for GI, GL, and CQI, respectively. Choline, cotinine, γ-butyrobetaine, and 36:3 phosphatidylserine plasmalogen were positively associated with GI and GL, whereas they were negatively associated with CQI. Fructose-glucose-galactose was negatively and positively associated with GI/GL and CQI, respectively. Consistent associations of 21 metabolites with both GI and CQI were found but in opposite directions. Negative associations of kynurenic acid, 22:1 sphingomyelin, and 38:6 phosphatidylethanolamine, as well as positive associations of 32:1 phosphatidylcholine with GI and GL were also observed. Pearson correlation coefficients between GI, GL, and CQI and the metabolomic profiles were 0.30, 0.22, and 0.27, respectively.

CONCLUSIONS

The GI, GL, and CQI were associated with specific metabolomic profiles in a Mediterranean population at high cardiovascular disease risk. Our findings may help in understanding the role of dietary carbohydrate indices in the development of cardiometabolic disorders. This trial was registered at isrctn.com as ISRCTN35739639.

The Effects of Creatine and Related Compounds on Cardiovascular System: From Basic to Applied Studies

Beneficial effects of creatine were firstly shown in sport, where itself has been recognized as an ergogenic substance, increasing exercise endurancе, muscle strength and lean body mass. Creatine supplementation is very interesting, due to the fact that creatine supplementation have been reported to be beneficial for wide spectrum of diseases and conditions referring neuro-degenerative, rheumatic diseases, myopathies, cancer, type 2 diabetes. Creatine is a principle component of the creatine kinase/phosphagen system. In cardiomyocytes, it plays an important role in the buffering and transport of chemical energy to ensure that supply meets the dynamic demands of the heart. Studies in mice proved that elevated creatine protects the heart from ischemia-reperfusion injury. A natural precursor of creatine, guanidinoacetic acid (GAA), plays an important role as an energy carrier/mediator in the cell. GAA is formed in the first step of creatine synthesis. Supplementation with GAA might be of great significance in some circumstances where biosynthesis of GAA is limited like deficient diet, kidney failure, renal insufficiency, exercise-related GAA depletion. Betaine is a neutral compound in the form of zwitterion. Betaine supplementation is associated with improved cognition, neuroprotection, cardioprotection and exercise physiology. Betaine insufficiency represents increased risk for secondary heart failure and acute myocardial infarction. This mini-review outlines the evidence in support of creatine and creatine related compounds (GAA and betaine) elevation and examines the pharmacological approaches that are currently available. Since data from the available studies, regarding cardioprotection are inconsistent, this review might help clarifying the benefits of creatine, GAA and betaine supplementation on cardiovascular system.

Circulating metabolites from the choline pathway and acute coronary syndromes in a Chinese case-control study

Background

Accumulating evidence shows that circulating levels of trimethylamine N-oxide, which is generated from the metabolism of dietary choline, may predict cardiovascular disease among Caucasians. Acute coronary syndrome (ACS), one common presentation of cardiovascular disease, is a spectrum of signs and symptoms due to acute decreased blood flow in the coronary arteries. The relationship between the metabolites from choline pathway and ACS remains unclear. We aimed to assess the associations of circulating metabolites from the choline pathway with ACS among a Chinese population, who consume a different dietary pattern than their Western counterparts.

Methods

We recruited 501 participants who were admitted to the Department of Cardiology, Zhongshan Hospital,Shanghai China between March 2017 and June 2018, including 254 ACS cases and 247 controls. Liquid chromatography-tandem mass spectrometry was used to measure circulating concentrations of metabolites in the choline pathway, including betaine, choline, trimethylamine, and trimethylamine N-oxide. A composite metabolite score using a weighted sum of these four metabolites, and the betaine/choline ratio were calculated. Multivariable logistic regressions were applied to estimate the association of metabolites with ACS, with adjustment of age, sex, body mass index, smoking index, history of diseases, and kidney function.

Results

After adjusting for traditional risk factors, per 1-standard deviation (SD) increment in choline was positively associated with the odds of ACS [odds ratio (OR), 95% confidence interval (CI), 1.77(1.44-2.18)], and the other metabolites were not associated with ACS at a statistical significance level. Compared with participants in the lowest quartile of the metabolite score, those in the highest quartile had higher odds of ACS [OR (95% CI), 3.18(1.85-5.54), p < 0.001 for trend]. Per 1-SD increment in metabolite score was positively associated with higher odds of ACS [OR (95% CI), 1.80 (1.37-2.40)], and per 1-SD increment in the betaine/choline ratio was inversely associated with the odds of ACS [OR (95% CI), 0.49 (0.39-0.60)].

Conclusions

Among our Chinese participants, trimethylamine N-oxide was not associated with ACS, while a composite metabolite score of metabolites from the choline pathway was associated with increased odds of ACS. The choline pathway metabolites may be related to the pathophysiology of ACS among Chinese.

Trimethylamine N-Oxide in Relation to Cardiometabolic Health-Cause or Effect?

Trimethylamine-N-oxide (TMAO) is generated in a microbial-mammalian co-metabolic pathway mainly from the digestion of meat-containing food and dietary quaternary amines such as phosphatidylcholine, choline, betaine, or L-carnitine. Fish intake provides a direct significant source of TMAO. Human observational studies previously reported a positive relationship between plasma TMAO concentrations and cardiometabolic diseases. Discrepancies and inconsistencies of recent investigations and previous studies questioned the role of TMAO in these diseases. Several animal studies reported neutral or even beneficial effects of TMAO or its precursors in cardiovascular disease model systems, supporting the clinically proven beneficial effects of its precursor, L-carnitine, or a sea-food rich diet (naturally containing TMAO) on cardiometabolic health. In this review, we summarize recent preclinical and epidemiological evidence on the effects of TMAO, in order to shed some light on the role of TMAO in cardiometabolic diseases, particularly as related to the microbiome.

Short-term treatment with a peroxisome proliferator-activated receptor α agonist influences plasma one-carbon metabolites and B-vitamin status in rats

INTRODUCTION

Peroxisome proliferator-activated receptors (PPARs) have been suggested to be involved in the regulation of one-carbon metabolism. Previously we have reported effects on plasma concentrations of metabolites along these pathways as well as markers of B-vitamin status in rats following treatment with a pan-PPAR agonist. Here we aimed to investigate the effect on these metabolites after specific activation of the PPARα and PPARγ subtypes.

METHODS

For a period of 12 days, Male Wistar rats (n = 20) were randomly allocated to receive treatment with the PPARα agonist WY-14.643 (n = 6), the PPARγ agonist rosiglitazone (n = 6) or placebo (n = 8). The animals were sacrificed under fasting conditions, and plasma concentration of metabolites were determined. Group differences were assessed by one-way ANOVA, and planned comparisons were performed for both active treatment groups towards the control group.

RESULTS

Treatment with a PPARα agonist was associated with increased plasma concentrations of most biomarkers, with the most pronounced differences observed for betaine, dimethylglycine, glycine, nicotinamide, methylnicotinamide, pyridoxal and methylmalonic acid. Lower levels were observed for flavin mononucleotide. Fewer associations were observed after treatment with a PPARγ agonist, and the most notable was increased plasma serine.

CONCLUSION

Treatment with a PPARα agonist influenced plasma concentration of one-carbon metabolites and markers of B-vitamin status. This confirms previous findings, suggesting specific involvement of PPARα in the regulation of these metabolic pathways as well as the status of closely related B-vitamins.

High Betaine, a Trimethylamine N-Oxide Related Metabolite, Is Prospectively Associated with Low Future Risk of Type 2 Diabetes Mellitus in the PREVEND Study

Background: Gut microbiota-related metabolites, trimethylamine-N-oxide (TMAO), choline, and betaine, have been shown to be associated with cardiovascular disease (CVD) risk. Moreover, lower plasma betaine concentrations have been reported in subjects with type 2 diabetes mellitus (T2DM). However, few studies have explored the association of betaine with incident T2DM, especially in the general population. The goals of this study were to evaluate the performance of a newly developed betaine assay and to prospectively explore the potential clinical associations of betaine and future risk of T2DM in a large population-based cohort. Methods: We developed a high-throughput, nuclear magnetic resonance (NMR) spectroscopy procedure for acquiring spectra that allow for the accurate quantification of plasma/serum betaine and TMAO. Assay performance for betaine quantification was assessed and Cox proportional hazards regression was employed to evaluate the association of betaine with incident T2DM in 4336 participants in the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study. Results: Betaine assay results were linear (y = 1.02X − 3.75) over a wide range of concentrations (26.0–1135 µM). The limit of blank (LOB), limit of detection (LOD) and limit of quantitation (LOQ) were 6.4, 8.9, and 13.2 µM, respectively. Coefficients of variation for intra- and inter-assay precision ranged from 1.5–4.3% and 2.5–5.5%, respectively. Deming regression analysis of results produced by NMR and liquid chromatography coupled to tandem mass spectrometry(LC-MS/MS) revealed an R² value of 0.94 (Y = 1.08x – 1.89) and a small bias for higher values by NMR. The reference interval, in a cohort of apparently healthy adult participants (n = 501), was determined to be 23.8 to 74.7 µM (mean of 42.9 ± 12.6 µM). In the PREVEND study (n = 4336, excluding subjects with T2DM at baseline), higher betaine was associated with older age and lower body mass index, total cholesterol, triglycerides, and hsCRP. During a median follow-up of 7.3 (interquartile range (IQR), 5.9–7.7) years, 224 new T2DM cases were ascertained. Cox proportional hazards regression models revealed that the highest tertile of betaine was associated with a lower incidence of T2DM. Hazard ratio (HR) for the crude model was 0.61 (95% CI: 0.44–0.85, p = 0.004). The association remained significant even after adjusting for multiple clinical covariates and T2DM risk factors, including fasting glucose. HR for the fully-adjusted model was 0.50 (95% CI: 0.32–0.80, p = 0.003). Conclusions: The newly developed NMR-based betaine assay exhibits performance characteristics that are consistent with usage in the clinical laboratory. Betaine levels may be useful for assessing the risk of future T2DM.

Metabolic Effects of Betaine: A Randomized Clinical Trial of Betaine Supplementation in Prediabetes

CONTEXT

Plasma betaine correlates with insulin sensitivity in humans. Betaine supplementation improves metabolic effects in mice fed a high-fat diet.

OBJECTIVE

To assess metabolic effects of oral betaine in obese participants with prediabetes.

DESIGN

A 12-week, parallel arm, randomized, double-masked, placebo-controlled trial.

SETTING

University-affiliated hospital.

PARTICIPANTS AND INTERVENTIONS

Persons with obesity and prediabetes (N = 27) were randomly assigned to receive betaine 3300 mg orally twice daily for 10 days, then 4950 mg twice daily for 12 weeks, or placebo.

MAIN OUTCOME MEASURES

Changes from baseline in insulin sensitivity, glycemia, hepatic fat, and endothelial function.

RESULTS

There was a 16.5-fold increase in plasma dimethylglycine [dimethylglycine (DMG); P < 0.0001] levels, but modest 1.3- and 1.5-fold increases in downstream serine and methionine levels, respectively, in the betaine vs placebo arm. Betaine tended to reduce fasting glucose levels (P = 0.08 vs placebo) but had no other effect on glycemia. Insulin area under curve after oral glucose was reduced for betaine treatment compared with placebo (P = 0.038). Insulin sensitivity, assessed by euglycemic hyperinsulinemic clamp, was not improved. Serum total cholesterol levels increased after betaine treatment compared with placebo (P = 0.032). There were no differences in change in intrahepatic triglyceride or endothelial function between groups.

CONCLUSION

DMG accumulation supports DMG dehydrogenase as rate limiting for betaine metabolism in persons with prediabetes. Betaine had little metabolic effect. Additional studies may elucidate mechanisms contributing to differences between preclinical and human responses to betaine, and whether supplementation of metabolites downstream of DMG improves metabolism.

Hepatoprotective effects of betaine on liver damages followed by myocardial infarction

Myocardial infarction is commonly considered as a leading cause of cardiovascular disease taking the lives of seven million people annually. Liver dysfunction is associated with cardiac diseases. The profile of abnormal liver functions in heart failure is not clearly defined. This study was designed to investigate the protective effects of betaine on liver injury after myocardial infarction induced by isoprenaline in rats. Forty-eight male rats were divided into four groups: the control group received normal diet and the experimental groups received 50, 150, and 250 mg kg^-1 body weight of betaine daily through gastric gavages for 60 days. All of experimental and control groups experienced myocardial infarction, induced by subcutaneous injection of 100 mg kg^-1 isoprenaline in two consecutive doses )8:00 AM to 8:00 PM). Liver enzymes including aspartate transaminase (AST) and alanine transaminase (ALT) were significantly reduced in the groups treated with betaine, compared with the control group. The total antioxidant capacity in the experimental groups, treated with betaine, showed a significant increase, compared with the control group. In the control group, severe lesions were created in the liver tissue, while degenerative changes of liver tissue significantly reduced in groups treated with different doses of betaine, showing the repair of liver tissue. Betaine decreased apoptosis in the experimental groups in comparison with the control group. Betaine showed a protective effect against biochemical and histological changes in liver tissue caused by the induction of myocardial infarction via isoprenaline injection.

Plasma Concentrations and Dietary Intakes of Choline and Betaine in Association With Atrial Fibrillation Risk: Results From 3 Prospective Cohorts With Different Health Profiles

Background

Although choline metabolism has been associated with atherosclerotic heart disease, less research attention has been paid to the associations of choline and its oxidative metabolite betaine with cardiac arrhythmias.

Methods and Results

We evaluated associations of plasma concentrations and dietary intakes of choline and betaine with long‐term atrial fibrillation (AF) risk in a community‐based cohort, HUSK ([the Hordaland Health Study] n=6949), and validated the findings in 2 patient cohorts: the Western Norway Coronary Angiography Cohort (n=4164) and the NORVIT (Norwegian B‐Vitamin) Trial (n=3733). Information on AF was obtained from the CVDNOR (Cardiovascular Disease in Norway) project. In HUSK, WECAC (Western Norway Coronary Angiography Cohort), and NORVIT, 552, 411, and 663 AF cases were identified during a median follow‐up time of 10.9, 7.3, and, 8.7 years, respectively. Plasma concentrations of choline and betaine were significantly positively associated with later AF risk after multivariable adjustments in HUSK. Such associations were independently replicated in the 2 external prospective patient cohorts. The pooled hazard ratio was 1.13 (95% confidence interval 1.08‐1.19, P<0.001) and 1.16 (95% confidence interval 1.10‐1.22, P<0.001) per SD increment for log‐transformed choline and betaine, respectively. Moreover, dietary intake of choline was marginally associated with AF risk (pooled hazard ratio 1.29, 95% confidence interval 1.01‐1.66, fifth versus first quintile), whereas no significant association was observed between dietary betaine and AF risk.

Conclusions

Our findings indicate that plasma concentrations as well as dietary intake of choline, but not betaine, are associated with subsequent risk of AF, suggesting a potential role of choline metabolism in the pathogenesis of AF.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov.Unique identifier: NCT00671346.

1H-NMR Based Serum Metabolomics Study to Investigate Hepatoprotective Effect of Qin-Jiao on Carbon Tetrachloride-Induced Acute Hepatotoxicity in Rats

Gentiana macrophylla Radix, commonly known as Qin-Jiao (QJ), was recorded alone to treat jaundice in Compendium of Materia Medica and has been frequently prescribed for treatment of liver disease in China. However, the underlying mechanism remains unknown. In the present work, QJ of 1,2 g/kg or silybin of 40 mg/kg (positive control) was orally given to rats for 7 days to verify the protective effect on acute liver damage induced by tetrachloride (CCl₄). Together with serum biochemistry and histopathological examination, ¹H-NMR based metabolomics work was carried out to investigate the efficacy. It turned out that QJ of 2 g/kg exerted comparable protective effect with positive control and partially recovered disturbed metabolism by CCl₄. Multivariate analysis was conducted and metabolites altered significantly among groups were assigned and discussed, including betaine, glucose, lactate, creatine, and LDL/VLDL. Metabolic regulations involved in QJ or silybin treatment were as follows: tricarboxylic acid (TCA) cycle, synthesis of LDL/VLDL, and gluconeogenesis were enhanced, while betaine metabolism, glycolysis, creatine metabolism, synthesis of ketone bodies, amino acids metabolism, and β-oxidation of fatty acids were suppressed. For the first time hepatoprotective effect of QJ on acute liver damage was revealed by ¹H-NMR based metabolomics, prompting understanding of the underlying mechanism.

A pilot study of the effect of human breast milk on urinary metabolome analysis in infants

BACKGROUND

This study aimed to examine the nutritional effect of breast feeding on healthy term infants by using urinary metabolome analysis.

METHODS

Urine samples were collected from 19 and 14 infants at 1 and 6 months, respectively. Infants were separated into two groups: the breast-fed group receiving <540 mL/week of their intake from formula (n=13 at 1 month; n=9 at 6 months); and the formula-fed group receiving no breast milk (BM) (n=6 at 1 month; n=5 at 6 months). Urinary metabolome analysis was performed using capillary electrophoresis-time-of-flight mass spectrometry (CE-TOF/MS).

RESULTS

A total of 29 metabolites were detected by CE-TOF/MS metabolome analysis in all samples. Urinary excretion of choline metabolites (choline base solution, N,N-dimethylglycine, sarcosine, and betaine) at 1 month were significantly (p<0.05) higher in breast-fed infants than in formula-fed infants. However, choline metabolites were not significantly different between the groups at 6 months. Urinary excretion of lactic acid in breast-fed infants at 1 and 6 months was significantly lower than that in formula-fed infants. Urinary l(-)-threonine and l-carnosine excretion at 1 month was significantly lower in breast-fed infants than in formula-fed infants, but it was not significantly different between the groups at 6 months.

CONCLUSIONS

The type of feeding in early infancy affects choline metabolism, as well as lactate, threonine, and carnosine levels, in healthy term infants. Urinary metabolome analysis by the CE-TOF/MS method is useful for assessing nutritional metabolism in infants.

Choline and its metabolites are differently associated with cardiometabolic risk factors, history of cardiovascular disease, and MRI-documented cerebrovascular disease in older adults

Background: There is a potential role of choline in cardiovascular and cerebrovascular disease through its involvement in lipid and one-carbon metabolism.Objective: We evaluated the associations of plasma choline and choline-related compounds with cardiometabolic risk factors, history of cardiovascular disease, and cerebrovascular pathology.Design: A cross-sectional subset of the Nutrition, Aging, and Memory in Elders cohort who had undergone MRI of the brain (n = 296; mean ± SD age: 73 ± 8.1 y) was assessed. Plasma concentrations of free choline, betaine, and phosphatidylcholine were measured with the use of liquid-chromatography-stable-isotope dilution-multiple-reaction monitoring-mass spectrometry. A volumetric analysis of MRI was used to determine the cerebrovascular pathology (white-matter hyperintensities and small- and large-vessel infarcts). Multiple linear and logistic regression models were used to examine relations of plasma measures with cardiometabolic risk factors, history of cardiovascular disease, and radiologic evidence of cerebrovascular pathology.Results: Higher concentrations of plasma choline were associated with an unfavorable cardiometabolic risk-factor profile [lower high-density lipoprotein (HDL) cholesterol, higher total homocysteine, and higher body mass index (BMI)] and greater odds of large-vessel cerebral vascular disease or history of cardiovascular disease but lower odds of small-vessel cerebral vascular disease. Conversely, higher concentrations of plasma betaine were associated with a favorable cardiometabolic risk-factor profile [lower low-density lipoprotein (LDL) cholesterol and triglycerides] and lower odds of diabetes. Higher concentrations of plasma phosphatidylcholine were associated with characteristics of both a favorable cardiometabolic risk-factor profile (higher HDL cholesterol, lower BMI, lower C-reactive protein, lower waist circumference, and lower odds of hypertension and diabetes) and an unfavorable profile (higher LDL cholesterol and triglycerides).Conclusion: Choline and its metabolites have differential associations with cardiometabolic risk factors and subtypes of vascular disease, thereby suggesting differing roles in the pathogenesis of cardiovascular and cerebral large-vessel disease compared with that of small-vessel disease.

Distinctive metabolomic fingerprint in scleroderma patients with pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) in systemic sclerosis (SS) identifies a poor prognosis subset of patients. Recent studies suggested a "metabolic theory" on the development of pulmonary arterial hypertension. On this basis we performed a metabolomic study in order to evaluate whether differences in pulmonary arterial blood metabolites were identifiable in SS patients with increased pulmonary vascular resistance (PVR).

METHODS

We studied 18 SS patients (age 58.7±15.6years) free of pulmonary fibrosis who underwent a right heart catheterization (RHC). A blood sample was collected during the RHC in the distal peripheral circulation of the pulmonary arteries to perform the metabolomic analysis.

RESULTS

Based on PVR we divided the population into Group A (n=8; PVR=1.16±0.23WU) and Group B (n=10; PVR=2.67±0.67WU; p<0.001 vs Group A). No significant differences were identified in terms of anthropometric, clinical, echo and therapeutic characteristics. At RHC the 2 groups showed a difference in mean pulmonary pressure values (Group A: 20±4mmHg; Group B: 27±3.4mmHg; p=0.03), with mild PAH in Group B. We applied an OSC-PLS-DA with a clear clusterization; SSc patients with PAH showed an increase in acetate, alanine, lactate, and lipoprotein levels and a decrease in γ-aminobutyrate, arginine, betaine, choline, creatine, creatinine, glucose, glutamate, glutamine, glycine, histidine, phenylalanine, and tyrosine levels CONCLUSIONS: Our results suggest that, despite similar clinical and disease-related parameters, SSc patients who develop PAH have an unfavorable metabolic profile able to cause an impaired production of metabolites with protective effects on endothelial cells.

Altered glucose metabolism and hypoxic response in alloxan-induced diabetic atherosclerosis in rabbits

Diabetes mellitus accelerates atherosclerosis that causes most cardiovascular events. Several metabolic pathways are considered to contribute to the development of atherosclerosis, but comprehensive metabolic alterations to atherosclerotic arterial cells remain unknown. The present study investigated metabolic changes and their relationship to vascular histopathological changes in the atherosclerotic arteries of rabbits with alloxan-induced diabetes. Diabetic atherosclerosis was induced in rabbit ilio-femoral arteries by injecting alloxan (100 mg/kg), injuring the arteries using a balloon, and feeding with a 0.5% cholesterol diet. We histologically assessed the atherosclerotic lesion development, cellular content, pimonidazole positive-hypoxic area, the nuclear localization of hypoxia-inducible factor-1α, and apoptosis. We evaluated comprehensive arterial metabolism by performing metabolomic analyses using capillary electrophoresis-time of flight mass spectrometry. We evaluated glucose uptake and its relationship to vascular hypoxia using 18F-fluorodeoxyglucose and pimonidazole. Plaque burden, macrophage content, and hypoxic areas were more prevalent in arteries with diabetic, than non-diabetic atherosclerosis. Metabolomic analyses highlighted 12 metabolites that were significantly altered between diabetic and non-diabetic atherosclerosis. A half of them were associated with glycolysis metabolites, and their levels were decreased in diabetic atherosclerosis. The uptake of glucose evaluated as 18F-fluorodeoxyglucose in atherosclerotic lesions increased according to increased macrophage content or hypoxic areas in non-diabetic, but not diabetic rabbits. Despite profound hypoxic areas, the nuclear localization of hypoxia-inducible factor-1α decreased and the number of apoptotic cells increased in diabetic atherosclerotic lesions. Altered glycolysis metabolism and an impaired response to hypoxia in atherosclerotic lesions under conditions of insulin-dependent diabetes might be involved in the development of diabetic atherosclerosis.

Increased Trimethylamine N-Oxide Portends High Mortality Risk Independent of Glycemic Control in Patients with Type 2 Diabetes Mellitus

BACKGROUND

Recent studies show a mechanistic link between intestinal microbial metabolism of dietary phosphatidylcholine and coronary artery disease pathogenesis. Concentrations of a proatherogenic gut microbe-generated metabolite, trimethylamine N-oxide (TMAO), predict increased incident cardiovascular disease risks in multiple cohorts. TMAO concentrations are increased in patients with type 2 diabetes mellitus (T2DM), but their prognostic value and relation to glycemic control are unclear.

METHODS

We examined the relationship between fasting TMAO and 2 of its nutrient precursors, choline and betaine, vs 3-year major adverse cardiac events and 5-year mortality in 1216 stable patients with T2DM who underwent elective diagnostic coronary angiography.

RESULTS

TMAO [4.4 μmol/L (interquartile range 2.8-7.7 μmol/L) vs 3.6 (2.3-5.7 μmol/L); P < 0.001] and choline concentrations were higher in individuals with T2DM vs healthy controls. Within T2DM patients, higher plasma TMAO was associated with a significant 3.0-fold increased 3-year major adverse cardiac event risk (P < 0.001) and a 3.6-fold increased 5-year mortality risk (P < 0.001). Following adjustments for traditional risk factors and high-sensitivity C-reactive protein, glycohemoglobin, and estimated glomerular filtration rate, increased TMAO concentrations remained predictive of both major adverse cardiac events and mortality risks in T2DM patients [e.g., quartiles 4 vs 1, hazard ratio 2.05 (95% CI, 1.31-3.20), P < 0.001; and 2.07 (95% CI, 1.37-3.14), P < 0.001, respectively].

CONCLUSIONS

Fasting plasma concentrations of the proatherogenic gut microbe-generated metabolite TMAO are higher in diabetic patients and portend higher major adverse cardiac events and mortality risks independent of traditional risk factors, renal function, and relationship to glycemic control.

Peroxisome Proliferator-Activated Receptor Activation is Associated with Altered Plasma One-Carbon Metabolites and B-Vitamin Status in Rats

Plasma concentrations of metabolites along the choline oxidation pathway have been linked to increased risk of major lifestyle diseases, and peroxisome proliferator-activated receptors (PPARs) have been suggested to be involved in the regulation of key enzymes along this pathway. In this study, we investigated the effect of PPAR activation on circulating and urinary one-carbon metabolites as well as markers of B-vitamin status. Male Wistar rats (n = 20) received for 50 weeks either a high-fat control diet or a high-fat diet with tetradecylthioacetic acid (TTA), a modified fatty acid and pan-PPAR agonist with high affinity towards PPARα. Hepatic gene expression of PPARα, PPARβ/δ and the enzymes involved in the choline oxidation pathway were analyzed and concentrations of metabolites were analyzed in plasma and urine. TTA treatment altered most biomarkers, and the largest effect sizes were observed for plasma concentrations of dimethylglycine, nicotinamide, methylnicotinamide, methylmalonic acid and pyridoxal, which were all higher in the TTA group (all p < 0.01). Hepatic Pparα mRNA was increased after TTA treatment, but genes of the choline oxidation pathway were not affected. Long-term TTA treatment was associated with pronounced alterations on the plasma and urinary concentrations of metabolites related to one-carbon metabolism and B-vitamin status in rats.

Serum metabolomics reveals betaine and phosphatidylcholine as potential biomarkers for the toxic responses of processed Aconitum carmichaelii Debx

We recently reported that processed Aconitum carmichaelii Debx (Bai-Fu-Pian in Chinese, BFP) elicits differential toxic responses in rats under various health conditions. The present study aimed to determine the graded toxicity of BFP so as to derive a safe therapeutic rationale in clinical practice. Sensitive and reliable biomarkers of toxicity were also identified, with the corresponding metabolic pathways being unveiled. Thirty male Sprague-Dawley rats were divided into five groups (n = 6) and received oral administration of BFP extract (0.32, 0.64, 1.28 or 2.56 g kg(-1) per day) or an equal volume of drinking water (control) for 15 days. The metabolomic profiles of rat serum were analyzed by liquid chromatography quadruple time-of-flight mass spectrometry (LC-Q-TOF-MS). Linear regression analysis and Ingenuity Pathway Analysis (IPA) were used to elucidate the differentiated altered metabolites and associated network relationships. Results from biochemical and histopathological examinations revealed that BFP could induce prominent toxicity in the heart, liver and kidneys at a dose of 2.56 g kg(-1) per day. Betaine up-regulation and phosphatidylcholine down-regulation were detected in the serum samples of drug-treated groups in a dose-dependent manner. In summary, betaine and phosphatidylcholine could be regarded as sensitive biomarkers for the toxic responses of BFP. Perturbations of RhoA signaling, choline metabolism and free radical scavenging were found to be partly responsible for the toxic effects of the herbal drug. Based on the metabolomics findings, we could establish a safe therapeutic range in the clinical use of BFP, with promising predictions of possible drug toxicity.

Listening to Our Gut: Contribution of Gut Microbiota and Cardiovascular Risk in Diabetes Pathogenesis

What we understand about diabetes from decades of genetics research is now being supplemented with exciting new evidence based on a better understanding of how one of the biggest "environmental" factors the body is exposed to is influencing the pathogenesis of disease. The recent discovery that certain dietary nutrients possessing a trimethylamine (TMA) moiety (namely choline/phosphatidylcholine and L-carnitine) participate in the development of atherosclerotic heart disease has renewed attention towards the contributions of gut microbiota in the development of cardiovascular diseases. Collectively, animal and human studies reveal that conversion of these nutrient precursors to trimethylamine N-oxide (TMAO) depends on both microbial composition and host factors, and can be induced by dietary exposures. In addition, circulating TMAO levels are strongly linked to cardiovascular disease risks and various adverse cardio-renal consequences. Our group and others have further demonstrated that circulating TMAO levels are elevated in patients with type 2 diabetes mellitus compared to healthy controls and gut microbiota-dependent phosphatidylcholine metabolism has been implicated in metabolic dysregulation and insulin resistance in animal models. Therefore, preventive strategies to minimize adverse consequences associated with TMAO generation in the diabetic population are warranted.

LC/MS-based polar metabolite profiling reveals gender differences in serum from patients with myocardial infarction

Myocardial infarction (MI), a leading cause of death worldwide, results from prolonged myocardial ischemia with necrosis of myocytes due to a blood supply obstruction to an area of the heart. Many studies have reported gender-related differences in the clinical features of MI, but the reasons for these differences remain unclear. In this study, we applied ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS) and various statistical methods-such as multivariate, pathway, and correlation analyses-to identify gender-specific metabolic patterns in polar metabolites in serum from healthy individuals and patients with MI. Patients with diagnosed MI (n=68), and age- and body mass index-matched healthy individuals (n=68), were included in this study. The partial least-squares discriminant analysis (PLS-DA) model was generated from metabolic profiling data, and the score plots showed a significant gender-related difference in patients with MI. Many pathways were associated with amino acids and purines; amino acids, acylcarnitines, and purines differed significantly between male and female patients with MI. This approach could be utilized to observe gender-specific metabolic pattern differences between healthy controls and patients with MI.

Extreme urinary betaine losses in type 2 diabetes combined with bezafibrate treatment are associated with losses of dimethylglycine and choline but not with increased losses of other osmolytes

PURPOSE

Betaine deficiency is a probable cardiovascular risk factor and a cause of elevated homocysteine. Urinary betaine excretion is increased by fibrate treatment, and is also often elevated in diabetes. Does fibrate further increase betaine excretion in diabetes, and does it affect the plasma concentrations and excretions of related metabolites and of other osmolytes?

METHODS

Samples from a previous study of type 2 diabetes were selected if participants were taking bezafibrate (n = 32). These samples were compared with participants matched for age and gender and not on a fibrate (comparator group, n = 64). Betaine, related metabolites, and osmolytes were measured in plasma and urine samples from these 96 participants.

RESULTS

Median urinary betaine excretion in those on bezafibrate was 5-fold higher than in the comparator group (p < 0.001), itself 3.5-fold higher than the median reported for healthy populations. In the bezafibrate group, median dimethylglycine excretion was higher (9-fold, p < 0.001). Excretions of choline, and of the osmolytes myo-inositol, taurine and glycerophosphorylcholine, were not significantly different between groups. Some participants excreted more betaine than usual dietary intakes. Several betaine fractional clearances were >100 %. Betaine excretion correlated with excretions of the osmolytes myo-inositol and glycerophosphorylcholine, and also with the excretion of choline and N,N-dimethylglycine, but it was inconclusive whether these relationships were affected by bezafibrate therapy.

CONCLUSIONS

Increased urinary betaine excretions in type 2 diabetes are further increased by fibrate treatment, sometimes to more than their dietary intake. Concurrent betaine supplementation may be beneficial.

Plasma dimethylglycine, nicotine exposure and risk of low bone mineral density and hip fracture: the Hordaland Health Study

In the large community-based Hordaland Health Study, low plasma dimethylglycine was associated with low bone mineral density in both middle-aged and elderly subjects and to an increased risk of subsequent hip fracture among the elderly. These associations seemed to be particularly strong among subjects exposed to nicotine.

INTRODUCTION

Dimethylglycine (DMG) is a product of the choline oxidation pathway and formed from betaine during the folate-independent remethylation of homocysteine (Hcy) to methionine. Elevated plasma DMG levels are associated with atherosclerotic cardiovascular disease and inflammation, which in turn are related to osteoporosis. High plasma total Hcy and low plasma choline are associated with low bone mineral density (BMD) and hip fractures, but the role of plasma DMG in bone health is unknown.

METHODS

We studied the associations of plasma DMG with BMD among 5315 participants (46-49 and 71-74 years old) and with hip fracture among 3310 participants (71-74 years old) enrolled in the Hordaland Health Study.

RESULTS

In age and sex-adjusted logistic regression models, subjects in the lowest versus highest DMG tertile were more likely to have low BMD (odds ratio [OR] 1.68, 95% confidence interval [CI] 1.43-1.99). The association was stronger in participants exposed compared to those unexposed to nicotine (OR 2.31, 95% CI 1.73-3.07 and OR 1.43, 95% CI 1.16-1.75, respectively, p interaction = 0.008). In the older cohort, Cox regression analyses adjusted for sex showed that low plasma DMG was associated with an increased risk of hip fracture (hazard ratio [HR] 1.70, 95% CI 1.28-2.26). A trend toward an even higher risk was found among women exposed to nicotine (HR 3.41, 95% CI 1.40-8.28).

CONCLUSION

Low plasma DMG was associated with low BMD and increased risk of hip fractures. A potential effect modification by nicotine exposure merits particular attention.

Betaine and Trimethylamine-N-Oxide as Predictors of Cardiovascular Outcomes Show Different Patterns in Diabetes Mellitus: An Observational Study

BACKGROUND

Betaine is a major osmolyte, also important in methyl group metabolism. Concentrations of betaine, its metabolite dimethylglycine and analog trimethylamine-N-oxide (TMAO) in blood are cardiovascular risk markers. Diabetes disturbs betaine: does diabetes alter associations between betaine-related measures and cardiovascular risk?

METHODS

Plasma samples were collected from 475 subjects four months after discharge following an acute coronary admission. Death (n = 81), secondary acute MI (n = 87), admission for heart failure (n = 85), unstable angina (n = 72) and all cardiovascular events (n = 283) were recorded (median follow-up: 1804 days).

RESULTS

High and low metabolite concentrations were defined as top or bottom quintile of the total cohort. In subjects with diabetes (n = 79), high plasma betaine was associated with increased frequencies of events; significantly for heart failure, hazard ratio 3.1 (1.2-8.2) and all cardiovascular events, HR 2.8 (1.4-5.5). In subjects without diabetes (n = 396), low plasma betaine was associated with events; significantly for secondary myocardial infarction, HR 2.1 (1.2-3.6), unstable angina, HR 2.3 (1.3-4.0), and all cardiovascular events, HR 1.4 (1.0-1.9). In diabetes, high TMAO was a marker of all outcomes, HR 2.7 (1.1-7.1) for death, 4.0 (1.6-9.8) for myocardial infarction, 4.6 (2.0-10.7) for heart failure, 9.1 (2.8-29.7) for unstable angina and 2.0 (1.1-3.6) for all cardiovascular events. In subjects without diabetes TMAO was only significant for death, HR 2.7 (1.6-4.8) and heart failure, HR 1.9 (1.1-3.4). Adding the estimated glomerular filtration rate to Cox regression models tended to increase the apparent risks associated with low betaine.

CONCLUSIONS

Elevated plasma betaine concentration is a marker of cardiovascular risk in diabetes; conversely low plasma betaine concentrations indicate increased risk in the absence of diabetes. We speculate that the difference reflects control of osmolyte retention in tissues. Elevated plasma TMAO is a strong risk marker in diabetes.