The controversial role of B-vitamins in cardiovascular risk: An update

Methyl donor diet attenuates intimal hyperplasia after vascular injury in rats

Environmental factors, particularly dietary habits, play an important role in cardiovascular disease susceptibility and progression through epigenetic modification. Previous studies have shown that hyperplastic vascular intima after endarterectomy is characterized by genome-wide hypomethylation. The purpose of this study was to investigate whether methyl donor diet affects intimal hyperplasia and the possible mechanisms involved. Intimal hyperplasia was induced in SD rats by carotid artery balloon injury. From 8 d before surgery to 28 d after surgery, the animals were fed a normal diet (ND) or a methyl donor diet (MD) supplemented with folic acid, vitamin B12, choline, betaine, and zinc. Carotid artery intimal hyperplasia was observed by histology, the effect of MD on carotid protein expression was analyzed by proteomics, functional clustering, signaling pathway, and upstream-downstream relationship of differentially expressed proteins were analyzed by bioinformatics. Results showed that MD attenuated balloon injury-induced intimal hyperplasia in rat carotid arteries. Proteomic analysis showed that there were many differentially expressed proteins in the common carotid arteries of rats fed with two different diets. The differentially expressed proteins are mainly related to the composition and function of the extracellular matrix (EMC), and changes in the EMC can lead to vascular remodeling by affecting fibrosis and stiffness of the blood vessel wall. Changes in the levels of vasculotropic proteins such as S100A9, ILF3, Serpinh1, Fbln5, LOX, HSPG2, and Fmod may be the reason why MD attenuates intimal hyperplasia. Supplementation with methyl donor nutrients may be a beneficial measure to prevent pathological vascular remodeling after injury.

Intakes of Folate, Vitamin B6, and Vitamin B12 in Relation to All-Cause and Cause-Specific Mortality: A National Population-Based Cohort

The evidence regarding the intake of dietary folate, vitamin B6, and vitamin B12 in relation to mortality in the general population is limited. This study aimed to examine the relationship between dietary intakes of folate, vitamin B6, and vitamin B12 in relation to all-cause and cause-specific mortality in a large U.S. cohort. This study included a total of 55,569 adults from the Third National Health and Nutrition Examination Survey (NHANES III) and NHANES 1999–2014. Vital data were determined by linking with the National Death Index records through 31 December 2015. Cox proportional hazards models were used to investigate the relationships of all-cause and cause-specific mortality with dietary folate, vitamin B6, and vitamin B12 intake. Dietary intakes of folate and vitamin B6 were inversely associated with mortality from all-cause, cardiovascular disease, and cancer for men and with mortality from all-cause and cardiovascular disease for women. In men, the multivariable hazard ratios (95% confidence intervals) for the highest versus lowest quintiles of folate and vitamin B6 were 0.77 (0.71–0.85) and 0.79 (0.71–0.86) for all-cause mortality, 0.59 (0.48–0.72) and 0.69 (0.56–0.85) for CVD mortality, and 0.68 (0.56–0.84) and 0.73 (0.60–0.90) for cancer mortality, respectively. Among women, the multivariable hazard ratios (95% confidence intervals) for the highest versus lowest quintiles of folate and vitamin B6 were 0.86 (0.78–0.95) and 0.88 (0.80–0.97) for all-cause mortality and 0.53 (0.41–0.69) and 0.56 (0.44–0.73) for CVD mortality, respectively. No significant associations between dietary vitamin B12 and all-cause and cause-specific mortality were observed. In conclusion, higher dietary intakes of folate and vitamin B6 were significantly associated with lower all-cause and cardiovascular mortality. Our findings suggest that increasing the intake of folate and vitamin B6 may lower the mortality risk among U.S. adults.

Homocysteine, Vitamins B6 and Folic Acid in Experimental Models of Myocardial Infarction and Heart Failure—How Strong Is That Link?

Cardiovascular diseases are the leading cause of death and the main cause of disability. In the last decade, homocysteine has been found to be a risk factor or a marker for cardiovascular diseases, including myocardial infarction (MI) and heart failure (HF). There are indications that vitamin B6 plays a significant role in the process of transsulfuration in homocysteine metabolism, specifically, in a part of the reaction in which homocysteine transfers a sulfhydryl group to serine to form α-ketobutyrate and cysteine. Therefore, an elevated homocysteine concentration (hyperhomocysteinemia) could be a consequence of vitamin B6 and/or folate deficiency. Hyperhomocysteinemia in turn could damage the endothelium and the blood vessel wall and induce worsening of atherosclerotic process, having a negative impact on the mechanisms underlying MI and HF, such as oxidative stress, inflammation, and altered function of gasotransmitters. Given the importance of the vitamin B6 in homocysteine metabolism, in this paper, we review its role in reducing oxidative stress and inflammation, influencing the functions of gasotransmitters, and improving vasodilatation and coronary flow in animal models of MI and HF.

Vitamin B-Related Gene Polymorphisms and Cardiovascular Disease

Hyperhomocysteinemia is an independent risk factor for atherosclerosis, even in early childhood. A mutation in genes which code homocysteine metabolism enzymes or deficiency of specific vitamin cofactors may cause hyperhomocysteinemia. Vitamin B complex has been correlated with serum homocysteine levels. Any abnormality in its metabolism or nutritional deficiency may lead to hyperhomocysteinemia. Both vitamin B complex and homocysteine levels are partly genetically determined. Specifically, the most studied polymorphism is 677T-C in exon 5 of the 5,10- methylenetetrahydrofolate reductase (MTHFR) gene, which plays an important role in folate's metabolism. This polymorphism has been shown correlated with hypertension and cardiovascular disease. Polymorphisms in methylenetetrahydrofolate dehydrogenase (NADP+ dependent) 1-like (MTHFD1L) gene have also been correlated with increased risk for coronary artery disease. Other common serious polymorphisms regard the area with high linkage disequilibrium, which included the neuroblastoma breakpoint family, NBPF3 gene, and ~ 12-50 kb upstream of the tissue nonspecific alkaline phosphatase gene. Finally, the polymorphisms which have been mostly associated with vitamin B12 concentration are the rs11254363 polymorphism at intron 52 of the intrinsic factor vitamin B12 receptor of the CUBN and the rs526934 polymorphism at intron 8 of transcobalamin I. To sum up, several polymorphisms have already been associated with vitamin B complexes and therefore homocysteine level, which highlights the complex nature of vitamin B genetics.

Hyperhomocysteinemia and Cardiovascular Disease: Is the Adenosinergic System the Missing Link?

The influence of hyperhomocysteinemia (HHCy) on cardiovascular disease (CVD) remains unclear. HHCy is associated with inflammation and atherosclerosis, and it is an independent risk factor for CVD, stroke and myocardial infarction. However, homocysteine (HCy)-lowering therapy does not affect the inflammatory state of CVD patients, and it has little influence on cardiovascular risk. The HCy degradation product hydrogen sulfide (H2S) is a cardioprotector. Previous research proposed a positive role of H2S in the cardiovascular system, and we discuss some recent data suggesting that HHCy worsens CVD by increasing the production of H2S, which decreases the expression of adenosine A2A receptors on the surface of immune and cardiovascular cells to cause inflammation and ischemia, respectively.

Modification of vitamin B6 on the associations of blood lead levels and cardiovascular diseases in the US adults

Background

Cardiovascular disease (CVD) is a leading cause of death in the US population. Lead exposure is an important risk factor of CVDs, as is associated with elevated homocysteine level and oxidative stress. We aim to examine whether vitamin B6, which has been shown to reduce homocysteine level, can modify the relationship between blood lead and the risk of CVDs.

Methods

Cross-sectional data on ever-report CVDs (congestive heart failure, coronary heart disease, angina pectoris, heart attack and stroke), blood lead level (BLL) and vitamin B6 in the form of plasma pyridoxal 5'-phosphate were obtained from US National Health and Nutrition Examination Survey 2005–2006 for adults≥20 years old. The association between CVDs and quartiles of BLL was estimated using multivariate logistic regression models adjusted for demographics factors, lifestyle variables, stress variables, comorbidities and CVD biomarkers (C reactive protein, homocysteine, cholesterol) and was stratified by vitamin B6 deficiency level (<20 nmol/L) and median value of vitamin B6 (42.5 nmol/L).

Results

Positive associations between BLL and CVDs only appeared in the vitamin B6 deficiency group, with quartile 2 to quartile 4 of BLL showing higher risk of CVDs (OR=3.1, 95% CI 0.9 to 10.6; OR=6.5, 95% CI 1.4 to 30.8; OR=5.5, 95% CI 1.4 to 21.7) compared with quartile 1. When stratified by median value of vitamin B6, a significant association between higher CVD risk with higher BLL was only observed in subjects with low vitamin B6 (p trend=0.004).

Conclusions

Vitamin B6 could modify the association between BLL and CVDs, which suggests a potential value of vitamin B6 in influencing the effects of lead exposure on the cardiovascular system.

Folate deficiency promotes differentiation of vascular smooth muscle cells without affecting the methylation status of regulated genes

Elevated serum homocysteine, an intermediate of cellular one-carbon metabolism, is an independent risk factor for cardiovascular disease (CVD). Folate deficiency increases serum homocysteine and may contribute to CVD progression. Vascular smooth muscle cells (VSMCs) regulate vascular contractility, but also contribute to repair processes in response to vascular injury. Nutritional deficiencies, like folate deficiency, are thought to impact on this phenotypic plasticity, possibly by epigenetic mechanisms. We have investigated the effect of folate deficiency on VSMCs in two cell culture systems representing early and late stages of smooth muscle cells differentiation. We find that folate deficiency promotes differentiation towards a more contractile phenotype as indicated by increased expression of respective marker genes. However, microarray analysis identified markers of striated muscle as the predominant gene expression change elicited by folate deficiency. These changes are not merely a reflection of cell cycle arrest, as foetal calf serum restriction or iron deficiency do not replicate the gene expression changes observed in response to folate deficiency. Folate deficiency only has a marginal effect on global DNA methylation. DNA methylation of CpG islands associated with genes regulated by folate deficiency remains unaffected. This supports our earlier findings in a mouse model system which also did not show any changes in global DNA methylation in response to folate and vitamin B6/B12 deficiency. These data suggest that folate deficiency enhances the expression of smooth muscle marker gene expression, promotes a shift towards a skeletal muscle phenotype, and does not regulate gene expression via DNA methylation.

Vitamin D3 reduces risk of cardiovascular and liver diseases by lowering homocysteine levels: double-blinded, randomised, placebo-controlled trial

The objective of this study was to evaluate the effect of vitamin D3 on total homocysteine (tHcy) and C-reactive protein (CRP) levels and liver and kidney function tests in overweight women with vitamin D deficiency. Therefore, a randomised, double-blind placebo, controlled clinical trial was conducted on 100 eligible women. Subjects were randomly divided into two groups: the placebo (n 50) and the vitamin D (n 50) which received 1250 µg vitamin D3 per week for 2 months. The participants' 25-hydroxyvitamin D (25(OH)D), tHcy, CRP, alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, creatinine and estimated glomerular filtration rate (eGFR) were measured and compared before and after treatment. Results showed that the tHcy, CRP, AST, ALT and eGFR levels after the 2nd month of vitamin D3 intervention were significantly (P < 0·001) decreased and the 25(OH)D, urea and creatinine levels were significantly (P < 0·001) increased in the treatment group. In the placebo group, no significant changes were identified throughout the follow-up period. In conclusion, vitamin D3 intervention with a treatment dose of 1250 µg/week for at least 2 months may help in lowering Hcy and CRP levels and may improve liver function tests, which in turn might help in minimising the risk of CVD and liver diseases among overweight women but negatively affect kidney function.

Differential Metabolic Pathways and Metabolites in a C57BL/6J Mouse Model of Alcoholic Liver Disease

Background

Alcoholic liver disease (ALD), an important cause of acute or chronic liver injury, results from binge drinking or long-term alcohol consumption. To date, there is no well-established mouse model with a comprehensive metabolic profile that mimics ALD in humans. This study aimed to explore the differential metabolic pathways and related differential metabolites in the liver of an ALD mouse model.

Material/Methods

A C57BL/6J mouse model of ALD was induced by alcohol feeding for 10 days plus binge alcohol feeding. The metabolomic profiles in the liver of the ALD mouse model was detected through ultra-high-pressure liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UHPLC/Q-TOF-MS).

Results

A total 35 metabolites were significantly altered during the development of ALD. These metabolites were correlated to multiple metabolic pathways, including purine metabolism, the pentose phosphate pathway, cysteine and methionine metabolism, D-glutamine and D-glutamate metabolism, pyrimidine metabolism, and vitamin B6 metabolism.

Conclusions

The findings of the present study reveal potential biomarkers of ALD, and provide further insights into the pathogenesis of ALD.

Compositional data analysis as an alternative paradigm for nutritional studies

BACKGROUND & AIM

Although the compositional nature of dietary data is well recognized, little attention has been given to the methods specifically developed for the statistical analysis of compositional data. The use of standard statistical procedures that ignore the relative nature of compositional elements can lead to spurious results when applied to crude data. This note proposes using a compositional data approach for the statistical analysis of nutritional data.

METHODS

The analyses of data from an Italian population study of 673 non-diabetic women aged 40-74 years were based on isometric log-ratio (ilr) transformation applied to three dietary compositions: seven-part macronutrients, nine-part vitamins and six-part minerals. The ilr transformation produces new variables that represent specific contrasts (balances) between the compositional parts. Different sequential binary partitions have been described and used as a means of flexibly defining balances on the basis of a researcher's interest, and the new variables (that are suitable for undergoing standard statistical procedures) have been included as covariates in linear regression models in order to examine the isocaloric associations between specific dietary balances and waist circumference (WC).

RESULTS

Regardless of the dietary compositions, total energy was positively and fibre intake was negatively associated with WC. Net of these effects and keeping constant the proportional relationships between the other dietary components, WC was negatively associated with the relative increase in starches, and positively associated with the relative niacin content. Vitamin C was negatively associated with WC, whereas folate content was positively related.

DISCUSSION

The proposed approach allows a clear interpretation of the relative roles of different dietary components within a holistic overview of a diet. The analyses involving WC provide some useful insights.

The Role of Nitric Oxide, ADMA, and Homocysteine in The Etiopathogenesis of Preeclampsia-Review

Preeclampsia is a serious, pregnancy-specific, multi-organ disease process of compound aetiology. It affects 3–6% of expecting mothers worldwide and it persists as a leading cause of maternal and foetal morbidity and mortality. In fact, hallmark features of preeclampsia (PE) result from vessel involvement and demonstrate maternal endothelium as a target tissue. Growing evidence suggests that chronic placental hypoperfusion triggers the production and release of certain agents that are responsible for endothelial activation and injury. In this review, we will present the latest findings on the role of nitric oxide, asymmetric dimethylarginine (ADMA), and homocysteine in the etiopathogenesis of preeclampsia and their possible clinical implications.

Clinical Advances in Immunonutrition and Atherosclerosis: A Review

Atherosclerosis is a chronic low-grade inflammatory disease that affects large and medium-sized arteries and is considered to be a major underlying cause of cardiovascular disease (CVD). The high risk of mortality by atherosclerosis has led to the development of new strategies for disease prevention and management, including immunonutrition. Plant-based dietary patterns, functional foods, dietary supplements, and bioactive compounds such as the Mediterranean Diet, berries, polyunsaturated fatty acids, ω-3 and ω-6, vitamins E, A, C, and D, coenzyme Q10, as well as phytochemicals including isoflavones, stilbenes, and sterols have been associated with improvement in atheroma plaque at an inflammatory level. However, many of these correlations have been obtained in vitro and in experimental animals' models. On one hand, the present review focuses on the evidence obtained from epidemiological, dietary intervention and supplementation studies in humans supporting the role of immunonutrient supplementation and its effect on anti-inflammatory response in atherosclerotic disease. On the other hand, this review also analyzes the possible molecular mechanisms underlying the protective action of these supplements, which may lead a novel therapeutic approach to prevent or attenuate diet-related disease, such as atherosclerosis.

Intake of vitamin B6, folate, and vitamin B12 and risk of coronary heart disease: a systematic review and dose-response meta-analysis of prospective cohort studies

The objective of this study was to quantify the association of B-vitamins intake with the future risk of coronary heart disease (CHD). A systematic search was performed with the use of PubMed and Scopus from inception to April 30, 2018. Prospective cohort studies evaluating the association of intake of folate, vitamin B6, and vitamin B12 with risk of CHD in the general population were included. A random-effects meta-analysis was performed. Eleven prospective cohort studies (total n = 369,746) with 5133 cases of CHD were included in the analyses. The relative risks were: 0.79 (95%CI: 0.69, 0.89; I² = 67%) for a 250 µg/d increment in folate intake; 0.87 (95%CI: 0.78, 0.96; I² = 80%) for a 0.5 mg/d increment in vitamin B6 intake; and 0.97 (95%CI: 0.80, 1.14: I² = 67%) for a 3 µg/d increment in vitamin B12 intake. The results did not change materially when the analyses were restricted only to dietary vitamins intake. A nonlinear dose-response meta-analysis demonstrated a linear inverse association between folate and vitamin B6 intake and risk of CHD. In conclusion, higher intake of folate and vitamin B6 is associated with a lower risk of CHD in the general population.

Association between blood marker analyses regarding physical fitness levels in Spanish older adults: A cross-sectional study from the PHYSMED project

Biomarkers have been postulated as essential variables to measure the effects of exercise on the human body. To investigate the relationship between physical fitness (PF) and blood biomarkers that are associated with disease risk in Spanish older adults, four hundred and twenty-nine adults (57% females) aged older than 55 years from a cross-sectional study were included. A battery of PF test was performed, and participants were divided into 3 groups: low, medium and high fitness. Blood samples were collected, and subjects were also grouped based on a particular biomarker being within its reference range. Furthermore, drug intake and dietary intake were considered for each participant. Higher concentrations out of the reference range were observed for vitamin 25(OH)D (67.9%) and total cholesterol (TC) (58.6%). Participants from the low PF group presented lower significant concentrations out of the reference range for vitamin B₁₂ and triglycerides; however, participants in the low PF group showed higher significant concentrations out of the reference range for total homocysteine, creatinine, TC, HDL-cholesterol and LDL-cholesterol (LDL-c) than those in the high PF group (all p<0.05). Considering drugs related to blood lipid modifications, subjects who regularly consumed lipid reducers presented higher significant concentrations out of the reference range for TC and LDL-c than participants who did not take these drugs (p<0.01). Participants from the high PF group presented better blood marker profiles, namely, lower blood markers related to disease risk out of the reference range. These blood markers could be used as a routine method for considering PF groups in older adults.

The Effects of Methionine-Enriched and Vitamins (Folate, Pyridoxine and Cobalamine)-Deficient Diet on Exploratory Activity in Rats - A Brief Report

The aim of this study was to evaluate the impact of increased homocysteine levels induced by methionine nutritional overload (twice as standard) and deficiency of the vitamins folate, pyridoxine and cobalamine, which plays an important role in homocysteine metabolism in anxiety-related behaviour, expressed by means of exploratory activity in rats. Twenty-three male Wistar albino rats (4 weeks old, 100±15 g body weight) were divided into three groups: control (n=8), methionine-enriched (Meth+, 7.7 g of methionine/kg chow, n=7) and methionine-enriched vitamin-deficient (Meth+Vit-, 7.7 g of methionine/ kg chow, deficient in folate, pyridoxine and cobalamine - 0.08, 0.01 and 0.01 mg/kg, n=8). All animals had free access to food and water for 30 days. Behavioural testing was performed using the elevated plus maze (EPM) test. Standard parameters for vertical exploratory activity, the number of rearings and the number of head-dippings, as well as the total exploratory activity (summarizing overall exploratory activity in the EPM) were significantly reduced following 30 days of methionine nutritional overload (p<0.05, p<0.05 and p<0.01, respectively). A methionine-enriched diet coupled with a reduction in some B vitamins resulted in a more pronounced decline in exploratory drive observed in the EPM test compared to the control (p<0.01). The decline in total exploratory activity associated with vitamin deficiency was significant compared to the Meth+ group (p<0.05). The results of this study highlight the important role of homocysteine in the modulation of exploratory activity in rats. Decreased exploratory drive induced by both a methionine-enriched and vitamin-deficient diet could be attributed to an anxiogenic effect of hyperhomocysteinemia.

Homocysteine-lowering interventions for preventing cardiovascular events

BACKGROUND

Cardiovascular disease, which includes coronary artery disease, stroke and peripheral vascular disease, is a leading cause of death worldwide. Homocysteine is an amino acid with biological functions in methionine metabolism. A postulated risk factor for cardiovascular disease is an elevated circulating total homocysteine level. The impact of homocysteine-lowering interventions, given to patients in the form of vitamins B6, B9 or B12 supplements, on cardiovascular events has been investigated. This is an update of a review previously published in 2009, 2013, and 2015.

OBJECTIVES

To determine whether homocysteine-lowering interventions, provided to patients with and without pre-existing cardiovascular disease are effective in preventing cardiovascular events, as well as reducing all-cause mortality, and to evaluate their safety.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2017, Issue 5), MEDLINE (1946 to 1 June 2017), Embase (1980 to 2017 week 22) and LILACS (1986 to 1 June 2017). We also searched Web of Science (1970 to 1 June 2017). We handsearched the reference lists of included papers. We also contacted researchers in the field. There was no language restriction in the search.

SELECTION CRITERIA

We included randomised controlled trials assessing the effects of homocysteine-lowering interventions for preventing cardiovascular events with a follow-up period of one year or longer. We considered myocardial infarction and stroke as the primary outcomes. We excluded studies in patients with end-stage renal disease.

DATA COLLECTION AND ANALYSIS

We performed study selection, 'Risk of bias' assessment and data extraction in duplicate. We estimated risk ratios (RR) for dichotomous outcomes. We calculated the number needed to treat for an additional beneficial outcome (NNTB). We measured statistical heterogeneity using the I2 statistic. We used a random-effects model. We conducted trial sequential analyses, Bayes factor, and fragility indices where appropriate.

MAIN RESULTS

In this third update, we identified three new randomised controlled trials, for a total of 15 randomised controlled trials involving 71,422 participants. Nine trials (60%) had low risk of bias, length of follow-up ranged from one to 7.3 years. Compared with placebo, there were no differences in effects of homocysteine-lowering interventions on myocardial infarction (homocysteine-lowering = 7.1% versus placebo = 6.0%; RR 1.02, 95% confidence interval (CI) 0.95 to 1.10, I2 = 0%, 12 trials; N = 46,699; Bayes factor 1.04, high-quality evidence), death from any cause (homocysteine-lowering = 11.7% versus placebo = 12.3%, RR 1.01, 95% CI 0.96 to 1.06, I2 = 0%, 11 trials, N = 44,817; Bayes factor = 1.05, high-quality evidence), or serious adverse events (homocysteine-lowering = 8.3% versus comparator = 8.5%, RR 1.07, 95% CI 1.00 to 1.14, I2 = 0%, eight trials, N = 35,788; high-quality evidence). Compared with placebo, homocysteine-lowering interventions were associated with reduced stroke outcome (homocysteine-lowering = 4.3% versus comparator = 5.1%, RR 0.90, 95% CI 0.82 to 0.99, I2 = 8%, 10 trials, N = 44,224; high-quality evidence). Compared with low doses, there were uncertain effects of high doses of homocysteine-lowering interventions on stroke (high = 10.8% versus low = 11.2%, RR 0.90, 95% CI 0.66 to 1.22, I2 = 72%, two trials, N = 3929; very low-quality evidence).We found no evidence of publication bias.

AUTHORS' CONCLUSIONS

In this third update of the Cochrane review, there were no differences in effects of homocysteine-lowering interventions in the form of supplements of vitamins B6, B9 or B12 given alone or in combination comparing with placebo on myocardial infarction, death from any cause or adverse events. In terms of stroke, this review found a small difference in effect favouring to homocysteine-lowering interventions in the form of supplements of vitamins B6, B9 or B12 given alone or in combination comparing with placebo.There were uncertain effects of enalapril plus folic acid compared with enalapril on stroke; approximately 143 (95% CI 85 to 428) people would need to be treated for 5.4 years to prevent 1 stroke, this evidence emerged from one mega-trial.Trial sequential analyses showed that additional trials are unlikely to increase the certainty about the findings of this issue regarding homocysteine-lowering interventions versus placebo. There is a need for additional trials comparing homocysteine-lowering interventions combined with antihypertensive medication versus antihypertensive medication, and homocysteine-lowering interventions at high doses versus homocysteine-lowering interventions at low doses. Potential trials should be large and co-operative.

Treatment of cardiovascular pathology with epigenetically active agents: Focus on natural and synthetic inhibitors of DNA methylation and histone deacetylation

Cardiovascular disease (CVD) retains a leadership as a major cause of human death worldwide. Although a substantial progress was attained in the development of cardioprotective and vasculoprotective drugs, a search for new efficient therapeutic strategies and promising targets is under way. Modulation of epigenetic CVD mechanisms through administration epigenetically active agents is one of such new approaches. Epigenetic mechanisms involve heritable changes in gene expression that are not linked to the alteration of DNA sequence. Pathogenesis of CVDs is associated with global genome-wide changes in DNA methylation and histone modifications. Epigenetically active compounds that influence activity of epigenetic modulators such as DNA methyltransferases (DNMTs), histone acetyltransferases, histone deacetylases (HDACs), etc. may correct these pathogenic changes in the epigenome and therefore be used for CVD therapy. To date, many epigenetically active natural substances (such as polyphenols and flavonoids) and synthetic compounds such as DNMT inhibitors or HDAC inhibitors are known. Both native and chemical DNMT and HDAC inhibitors possess a wide range of cytoprotective activities such as anti-inflammatory, antioxidant, anti-apoptotic, anti-anfibrotic, and anti-hypertrophic properties, which are beneficial of treatment of a variety of CVDs. However, so far, only synthetic DNMT inhibitors enter clinical trials while synthetic HDAC inhibitors are still under evaluation in preclinical studies. In this review, we consider epigenetic mechanisms such as DNA methylation and histone modifications in cardiovascular pathology and the epigenetics-based therapeutic approaches focused on the implementation of DNMT and HDAC inhibitors.

National Lipid Association Annual Summary of Clinical Lipidology 2016

The National Lipid Association (NLA) Annual Summary of Clinical Lipidology is a yearly updated summary of principles important to the patient-centered evaluation, management, and care of patients with dyslipidemia. This summary is intended to be a "living document," with future annual updates based on emerging science, clinical considerations, and new NLA Position, Consensus, and Scientific Statements, thus providing an ongoing resource that applies the latest in medical science towards the clinical management of patients with dyslipidemia. Topics include the NLA Recommendations for Patient-Centered Management of Dyslipidemia, genetics, Familial Hypercholesterolemia, secondary causes of dyslipidemia, biomarkers and advanced lipid testing, nutrition, physical activity, obesity, adiposopathy, metabolic syndrome, diabetes mellitus, lipid pharmacotherapy, lipid-altering drug interactions, lipoprotein apheresis, dyslipidemia management and treatment based upon age (children, adolescents, and older individuals), dyslipidemia considerations based upon race, ethnicity and gender, dyslipidemia and human immune virus infection, dyslipidemia and immune disorders, adherence strategies and collaborative care, and lipid-altering drugs in development. Hyperlinks direct the reader to sentinel online tables, charts, and figures relevant to lipidology, access to online atherosclerotic cardiovascular disease risk calculators, worldwide lipid guidelines, recommendations, and position/scientific statements, as well as links to online audio files, websites, slide shows, applications, continuing medical education opportunities, and patient information.

Impact of Iron and Homocysteine Levels on T Peak-to-End Interval and Tp-e/QT Ratio in Elite Athletes

BACKGROUND

Electrocardiography (ECG) is frequently used in preparticipation evaluation of competitive athletes. Repolarization heterogeneities on ECG is a well-known indicator for malignant ventricular arrhythmias and sudden cardiac death. We aimed to investigate the effect of iron and homocysteine levels on arrhythmogenic indicators, T peak-to-end (Tp-e) interval, and Tp-e/QT ratio in elite athletes.

METHODS

A total of 72 players (48 football and 24 basketball) with a mean age of 25.4 ± 5.0 years were included to the analysis. Blood biochemistry, homocysteine level, and iron parameters (transferrin saturation and serum iron) were obtained by standard methods. Duration of QRS, QT interval, and Tp-e interval were measured manually on the precordial leads and Tp-e/QT ratio was calculated.

RESULTS

Baseline demographic and clinical characteristics of the study population were compared in two groups according to the median value of Tp-e/QT = 0.219. Both iron and transferrin saturations were higher in the above median group (P = 0.001 and P = 0.002, respectively), however, homocysteine levels were not statistically different among two groups (P = 0.405). In correlation analysis, both serum iron and transferrin saturation were significantly correlated with Tp-e interval (r = 0.368; P = 0.001 and r = 0.394; P = 0.00, respectively) and Tp-e/QT ratio (r = 0.357; P = 0.002 and r = 0.372; P = 0.001, respectively). Multiple stepwise regression analysis revealed that transferrin saturation was an independent predictor of Tp-e interval and Tp-e/QT ratio (β = 0.325; P = 0.002 and β = 0.372; P = 0.001, respectively).

CONCLUSION

This study showed an independent relationship between iron status and Tp-e interval and Tp-e/QT ratios of elite sport players which were also not correlated with serum homocysteine levels.

Compilation of a standardised international folate database for EPIC

This paper describes the methodology applied for compiling an "international end-user" folate database. This work benefits from the unique dataset offered by the European Prospective Investigation into Cancer and Nutrition (EPIC) (N=520,000 subjects in 23 centres). Compilation was done in four steps: (1) identify folate-free foods then find folate values for (2) folate-rich foods common across EPIC countries, (3) the remaining "common" foods, and (4) "country-specific" foods. Compiled folate values were concurrently standardised in terms of unit, mode of expression and chemical analysis, using information in national food composition tables (FCT). 43-70% total folate values were documented as measured by microbiological assay. Foods reported in EPIC were either matched directly to FCT foods, treated as recipes or weighted averages. This work has produced the first standardised folate dataset in Europe, which was used to calculate folate intakes in EPIC; a prerequisite to study the relation between folate intake and diseases.

Homocysteine-lowering interventions for preventing cardiovascular events

BACKGROUND

Cardiovascular disease, which includes coronary artery disease, stroke and congestive heart failure, is a leading cause of death worldwide. Homocysteine is an amino acid with biological functions in methionine metabolism. A postulated risk factor is an elevated circulating total homocysteine level, which is associated with cardiovascular events. The impact of homocysteine-lowering interventions, given to patients in the form of vitamins B6, B9 or B12 supplements, on cardiovascular events. This is an update of a review previously published in 2009 and 2013.

OBJECTIVES

To determine whether homocysteine-lowering interventions, provided in patients with and without pre-existing cardiovascular disease are effective in preventing cardiovascular events, as well as all-cause mortality and evaluate their safety.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2014, Issue 1), MEDLINE (1950 to January week 5 2014), EMBASE (1980 to 2014 week 6) and LILACS (1986 to February 2014). We also searched Web of Science (1970 to 7 February 2014). We handsearched the reference lists of included papers. We also contacted researchers in the field. There was no language restriction in the search.

SELECTION CRITERIA

We included randomised controlled trials assessing the effects of homocysteine-lowering interventions for preventing cardiovascular events with a follow-up period of one year or longer. We considered myocardial infarction and stroke as the primary outcomes. We excluded studies in patients with end-stage renal disease.

DATA COLLECTION AND ANALYSIS

We performed study selection, 'Risk of bias' assessment and data extraction in duplicate. We estimated risk ratios (RR) for dichotomous outcomes. We measured statistical heterogeneity using the I(2) statistic. We used a random-effects model.

MAIN RESULTS

In this second updated Cochrane Review, we identified no new randomised controlled trials. Therefore, this new version includes 12 randomised controlled trials involving 47,429 participants. In general terms, 75% (9/12) trials had a low risk of bias. Homocysteine-lowering interventions compared with placebo did not significantly affect non-fatal or fatal myocardial infarction (1743/23,590 (7.38%) versus 1247/20,190 (6.17%); RR 1.02, 95% confidence interval (CI) 0.95 to 1.10, I(2) = 0%, high quality evidence), stroke (968/22,348 (4.33%) versus 974/18,957 (5.13%); RR 0.91, 95% CI 0.82 to 1.0, I(2) = 11%, high quality evidence) or death from any cause (2784/22,648 (12.29%) versus 2502/19,250 (10.64%); RR 1.01, 95% CI 0.96 to 1.07, I(2) = 6%, high quality evidence). Homocysteine-lowering interventions compared with placebo did not significantly affect serious adverse events (cancer) (1558/18,130 (8.59%) versus 1334/14,739 (9.05%); RR 1.06, 95% CI 0.98 to 1.13; I(2) = 0%, high quality evidence).

AUTHORS' CONCLUSIONS

This second update of this Cochrane Review found no evidence to suggest that homocysteine-lowering interventions in the form of supplements of vitamins B6, B9 or B12 given alone or in combination should be used for preventing cardiovascular events. Furthermore, there is no evidence to suggest that homocysteine-lowering interventions are associated with an increased risk of cancer.

National Lipid Association Annual Summary of Clinical Lipidology 2015

The National Lipid Association (NLA) Annual Summary of Clinical Lipidology 2015 is a summary of principles important to the patient-centered evaluation, management, and care of patients with dyslipidemia. This summary is intended to be a "living document," with future annual updates based on emerging science, clinical considerations, and new NLA Position and Consensus Statements. The goal is to provide clinicians an ongoing resource that translates the latest advances in medical science toward the evaluation and treatment of patients with dyslipidemia. The 2015 NLA Annual Summary of Clinical Lipidology was founded on the principles of evidence-based medicine and is generally consistent with established national and international lipid guidelines. Topics include a general discussion of the 2014 NLA Recommendations for Patient-Centered Management of Dyslipidemia, genetics, secondary causes of dyslipidemia, biomarkers and "advanced lipid testing," medical nutrition, physical activity, obesity, pharmacotherapy, statin safety, lipid-altering drug interactions, lipoprotein apheresis, dyslipidemia in children and adolescence, dyslipidemia in older individuals, race/ethnicity, and women, health information technology and electronic medical records, as well as investigational lipid-altering drugs in development.

Association of homocysteinaemia with hyperglycaemia, dyslipidaemia, hypertension and obesity

AIM

Hyperhomocysteinaemia and the metabolic syndrome are associated with increased cardiovascular risk. We investigated whether there is a link between the metabolic syndrome or its components and homocysteine levels in a population without cardiovascular disease.

METHODS

From the population sample of 382 participants (286 females and 96 males) we isolated those reflecting the metabolic syndrome and determined their homocysteine levels. We then evaluated the association of homocysteine with hyperglycaemia, hypertriglyceridaemia, hypercholesterolaemia, hypertension and obesity, using a significance level of p = 0.05. Enzymatic methods were used for all biochemical parameters.

RESULTS

We found the statistical relationship between homocysteine and the metabolic syndrome as follows: hyperglycaemia (p = 0.175), hypertriglyceridaemia (p = 0.442), hypercholesterolaemia (p = 0.480), obesity (p = 0.080); and hypertension: systolic pressure (p = 0.002) and diastolic pressure (p = 0.033).

CONCLUSION

We found no statistically significant association between baseline plasma homocysteine levels and the metabolic syndrome, except for hypertension.

Homocysteine-lowering interventions for preventing cardiovascular events

BACKGROUND

Cardiovascular disease (including coronary artery disease, stroke and congestive heart failure), is a leading cause of death worldwide. Homocysteine is an amino acid with biological functions in methionine metabolism. A postulated risk factor is elevated circulating total homocysteine levels, which are associated with cardiovascular events. This is an update of a review previously published in 2009.

OBJECTIVES

To assess the clinical effectiveness of homocysteine-lowering interventions in people with or without pre-existing cardiovascular disease.

SEARCH METHODS

We searched The Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (2012, Issue 2), MEDLINE (1950 to Feb week 2 2012), EMBASE (1980 to 2012 week 07), and LILACS (1986 to February 2012). We also searched ISI Web of Science (1970 to February 2012). We handsearched the reference lists of included papers. We also contacted researchers in the field. There was no language restriction in the search.

SELECTION CRITERIA

We included randomised controlled trials assessing the effects of homocysteine-lowering interventions for preventing cardiovascular events with a follow-up period of one year or longer. We considered myocardial infarction and stroke as the primary outcomes. We excluded studies in patients with end-stage renal disease.

DATA COLLECTION AND ANALYSIS

We performed study selection, 'Risk of bias' assessment and data extraction in duplicate. We estimated risk ratios (RR) for dichotomous outcomes. We measured statistical heterogeneity using I(2). We used a random-effects model.

MAIN RESULTS

In this updated systematic review, we identified four new randomised trials, resulting in a total of 12 randomised controlled trials involving 47,429 participants. In general terms, the trials had a low risk of bias. Homocysteine-lowering interventions compared with placebo did not significantly affect non-fatal or fatal myocardial infarction (pooled RR 1.02, 95% CI 0.95 to 1.10, I(2) = 0%), stroke (pooled RR 0.91, 95% CI 0.82 to 1.0, I(2) = 11%) or death by any cause (pooled RR 1.01 (95% CI 0.96 to 1.07, I(2): 6%)). Homocysteine-lowering interventions compared with placebo did not significantly affect serious adverse events (cancer) (1 RR 1.06, 95% CI 0.98 to 1.13; I(2) = 0%).

AUTHORS' CONCLUSIONS

This updated Cochrane review found no evidence to suggest that homocysteine-lowering interventions in the form of supplements of vitamins B6, B9 or B12 given alone or in combination should be used for preventing cardiovascular events. Furthermore, there is no evidence suggesting that homocysteine-lowering interventions are associated with an increased risk of cancer.

Folate and risk of coronary heart disease: a meta-analysis of prospective studies

BACKGROUND AND AIMS

Epidemiologic studies are inconsistent regarding the association between folate and coronary heart disease (CHD) risk. The aim was to perform a meta-analysis to determine whether an association exists between folate and total CHD endpoints in prospective studies.

METHODS AND RESULTS

We searched the PUBMED and EMBASE databases for studies conducted from 1966 through August 2010. Data were independently abstracted by 2 investigators using a standardized protocol. Study-specific risk estimates were combined by using a random effects model. A total of 14 studies were included in the meta-analysis: 7 studies on dietary folate intake and 8 studies on blood folate levels. For dietary intake, the summary relative risk (RR) indicated a significant association between the highest folate intake and reduced risk of CHD (summary RR: 0.69; 95% CI: 0.60, 0.80). Furthermore, an increase in folate intake of 200 ug/day was associated with a 12% decrease in the risk of developing CHD (summary RR: 0.88; 95% CI: 0.82, 0.94). For blood folate levels, we also found a borderline inverse association of highest blood folate levels on CHD risk (summary RR: 0.74; 95% CI: 0.53, 1.02); our dose-response analysis indicated that an increment in blood folate levels of 5 mmol/l was associated with an 8% decrease in the risk of developing CHD (summary RR: 0.92; 95% CI: 0.84, 1.00).

CONCLUSION

This meta-analysis suggests that dietary folate intake and blood folate level are inversely associated with CHD risk.

Cardiovascular effects of B-vitamins and/or N-3 fatty acids: the SU.FOL.OM3 trial

BACKGROUND

Mechanisms involved in coronary stenosis evolution are different than those involved in clinical events. Because of differential vascular effects, N-3 polyunsatured fatty acids (PUFA) and B vitamins could have differential effects on different types of cardiovascular clinical events in high-risk patients.

METHODS

We analyzed the effects of n-3 PUFA and of B vitamins on both coronary revascularization and on hard coronary events risks in a subgroup of the SU.FOL.OM3 trial, a randomized, double-blind, placebo-controlled secondary prevention trial. Data were analyzed according to the intention-to-treat principle, with the use of Cox proportional-hazards models.

RESULTS

After a mean follow-up of 4.2 ± 1.0 years among the 1,863 participants with coronary heart disease, 163 coronary revascularizations were performed, and 95 patients experienced a hard coronary event. Neither treatment with n-3 PUFA, nor treatment with B vitamins was associated with any significant effect on the occurrence of hard coronary events. Allocation to n-3 PUFA was not associated with any significant effect on coronary revascularization. However, treatment with B vitamins was associated with a statistically significant 52% increase in the risk of coronary revascularization (multivariate HR: 1.52; 95% CI: [1.11-2.10]; p=0.01).

CONCLUSIONS

Neither n-3 PUFA, nor B vitamins reduced the rates of hard coronary events and of coronary revascularization. Furthermore, B vitamins significantly increased the rate of coronary revascularization. Consistent with the findings of previous trials, our results do not support the routine use of dietary supplements containing n-3 PUFA and argue against using dietary supplements containing B-vitamins in coronary patients in secondary cardiovascular prevention.

Prediction of all-cause mortality by B group vitamin status in the elderly

BACKGROUND & AIMS

Little is known about the direct relationship of B vitamins to mortality in the elderly. All-cause mortality by vitamin B status, using dietary (B-1, B-2, niacin, B-6) or biochemical data (erythrocyte transketolase reductase, erythrocyte glutathione reductase, plasma pyridoxal-phosphate, folate and serum B-12) was evaluated.

METHODS

The Taiwanese Elderly Nutrition and Health Survey (1999-2000) provided 1747 participants 65 years and over. Dietary and biochemical data were collected at baseline. Survivorship was determined until December 31, 2008.

RESULTS

Survivors had higher vitamin B-1 and niacin intakes and pyridoxal-phosphate and folate concentrations. Controlled for confounders, and relative to the lowest tertile of vitamin B-1 or B-6 intakes, the hazard ratios (95% confidence interval) for tertile 3 were 0.74 (0.58-0.95) and 0.74 (0.57-0.97); both p for trend values were <0.05. Further adjustment for dietary diversity led to insignificant findings. For pyridoxal-phosphate, compared to those with deficiency levels, the multivariable-adjusted hazard ratios (95% confidence interval) for adequacy was 0.52 (0.38-0.71) with p for trend <0.0001 and unchanged with dietary diversity adjustment.

CONCLUSIONS

Higher vitamin B-1 and B-6 intakes and plasma pyridoxal-phosphate were associated with lower risk of mortality up to 10 years and could be achieved by increased dietary diversity.

Comparison of standardised dietary folate intake across ten countries participating in the European Prospective Investigation into Cancer and Nutrition

Folate plays an important role in the synthesis and methylation of DNA as a cofactor in one-carbon metabolism. Inadequate folate intake has been linked to adverse health events. However, comparable information on dietary folate intake across European countries has never been reported. The objective of the present study was to describe the dietary folate intake and its food sources in ten countries in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. A cross-sectional analysis was conducted in 36 034 participants (aged 35–74 years) who completed a single 24 h dietary recall using a computerised interview software program, EPIC-Soft® (International Agency for Research on Cancer, Lyon). Dietary folate intake was estimated using the standardised EPIC Nutrient DataBase, adjusted for age, energy intake, weight and height and weighted by season and day of recall. Adjusted mean dietary folate intake in most centres ranged from 250 to 350 μg/d in men and 200 to 300 μg/d in women. Folate intake tended to be lower among current smokers and heavier alcohol drinkers and to increase with educational level, especially in women. Supplement users (any types) were likely to report higher dietary folate intake in most centres. Vegetables, cereals and fruits, nuts and seeds were the main contributors to folate intake. Nonetheless, the type and pattern of consumption of these main food items varied across the centres. These first comparisons of standardised dietary folate intakes across different European populations show moderate regional differences (except the UK health conscious group), and variation by sex, educational level, smoking and alcohol-drinking status, and supplement use.

A low COMT activity haplotype is associated with recurrent preeclampsia in a Norwegian population cohort (HUNT2)

The etiology of preeclampsia is complex, with susceptibility being attributable to multiple environmental factors and a large genetic component. Although many candidate genes for preeclampsia have been suggested and studied, the specific causative genes still remain to be identified. Catechol-O-methyltransferase (COMT) is an enzyme involved in catecholamine and estrogen degradation and has recently been ascribed a role in development of preeclampsia. In the present study, we have examined the COMT gene by genotyping the functional Val108/158Met polymorphism (rs4680) and an additional single-nucleotide polymorphism, rs6269, predicting COMT activity haplotypes in a large Norwegian case/control cohort (n(cases)= 1135, n(controls)= 2262). A low COMT activity haplotype is associated with recurrent preeclampsia in our cohort. This may support the role of redox-regulated signaling and oxidative stress in preeclampsia pathogenesis as suggested by recent studies in a genetic mouse model. The COMT gene might be a genetic risk factor shared between preeclampsia and cardiovascular diseases.

Perinatal folate supply: relevance in health outcome parameters

The importance of physiological supply of folate is well recognized in human health; the crucial roles of folate in one-carbon metabolism for physiological DNA synthesis and cell division, as well as in the conversion of homocysteine (Hcy) to methionine, and subsequently, to S-adenosylmethionine, have been convincingly demonstrated. Improved folate status may reduce the risk of macrocytic anaemia, cardiovascular diseases, neuropsychiatric disorders and adverse pregnancy outcomes. Inadequate folate status results in a decrease in the methylation cycle and in increased blood levels of the neurotoxic Hcy. The aim of this review is to provide insight into the influence of folate status on pregnancy health outcomes, and to consider increasing evidence of a link between the extent of genome/epigenome damage and elevated risk for adverse obstetrical endpoints. Pregnant women are at risk for folate insufficiency because of the increased need for folate for rapid fetal growth, placental development and enlargement of the uterus. Inadequate folate status may cause fetal malformations, impaired fetal growth, pre-term delivery and maternal anaemia. Even some diseases of the placenta may arise from folate deficiencies. Fetal growth seems to be vulnerable to maternal folate status during the periconception period, because it has the potential to affect both the closure of the neural tube and several epigenetic mechanisms within the placenta and the fetus. Mainly on the basis of the well recognized link between maternal folate status and fetal neural tube defects, women are advised to receive folic acid supplement during the periconceptional period. Because an adequate folate supply seems to play an important role in the implantation and development of the placenta and in improving endothelial function, folic acid supplementation in the late first trimester or early second trimester might also be beneficial.