Homocysteine or Renal Impairment

Cardiovascular disease in systemic lupus erythematosus

There is a well-known increased risk for cardiovascular disease that contributes to morbidity and mortality in systemic lupus erythematosus (SLE). Major adverse cardiovascular events and subclinical atherosclerosis are both increased in this patient population. While traditional cardiac risk factors do contribute to the increased risk that is seen, lupus disease-related factors, medications, and genetic factors also impact the overall risk. SLE-specific inflammation, including oxidized lipids, cytokines, and altered immune cell subtypes all are likely to play a role in the pathogenesis of atherosclerotic plaques. Research is ongoing to identify biomarkers that can help clinicians to predict which SLE patients are at the greatest risk for cardiovascular disease (CVD). While SLE-specific treatment regimens for the prevention of cardiovascular events have not been identified, current strategies include minimization of traditional cardiac risk factors and lowering of overall lupus disease activity.

Correlation between plasma homocysteine and first myocardial infarction in young patients: Case-control study in Constanta County, Romania

An elevated level of total plasma homocysteine has been associated with a higher risk of atherosclerosis and coronary heart disease. The aim of our research was to study the relation between homocysteine and myocardial infarction (MI) in young patients. We conducted a case-control study in Constanţa County, Romania including 61 patients, divided in two groups. The first group, the MI group, consisted of 28 patients, male (67.9%) and female (32.1%) aged less than 45 years who were consecutively admitted to the Intensive Coronary Care Unit of the Emergency County Hospital of Constanţa from September 1, 2017 to August 31, 2018 (12 months), with an established diagnosis of first acute MI. The second group, the control group, included 33 patients, male (75.8%) and female (24.2%) aged less than 45 years, with cardiovascular risk factors and/or stable angina pectoris that were consecutively addressed for ambulatory cardiac evaluation at the Outpatient Clinic of Emergency County Hospital of Constanţa during the same period. Fasting plasma homocysteine was determined in both groups, within 24 h after MI onset, respectively after first cardiac exam in the controls. High homocysteine was statistically confirmed to be a risk factor in the study group, especially in association with smoking, chronic kidney disease (CKD), and to a lesser extent with diabetes mellitus (DM) and hypertension. Data analysis was performed using IBM SPSS Statistics 23. The procedures used included descriptive statistics, parametric statistical tests (Independent sample t-test), non-parametric statistical tests [Chi-square test of the association, with the evaluation of odds ratio (OR)]; the significance level used in the analysis (P-value) was 0.05. After adjusting for variables, our study results pointed out a strong association between plasma homocysteine and first acute MI among young patients, emphasising plasma homocysteine as a possible risk factor for myocardial infarction.

Plasma Homocysteine and Cardiovascular Organ Damage in a Population with a High Prevalence of Risk Factors

PURPOSE

It is unclear whether plasma homocysteine (Hcy) has a direct noxious impact on the cardiovascular (CV) system or whether its association with cardiovascular events (CVEs) is mediated by established risk factors. To explore the role of Hcy in CV impairment, the study evaluated cross-sectional relationships between plasma Hcy and indices of CV organ damage together with the associations of these indices with the history of CVEs.

METHODS

In 269 patients with a high prevalence of diabetes, dyslipidemia, and hypertension, the carotid intima-media thickness, ankle-brachial index (ABI), reactive hyperemic index, carotid-femoral pulse wave velocity (cfPWV), left ventricular (LV) mass, and cardiac index were measured.

RESULTS

132 patients had carotid plaque, 31 ABI < 0.90, 126 endothelial dysfunction, 66 increased cfPWV, 125 LV hypertrophy (LVH), 153 decreased cardiac index, and 115 a history of CVEs. Plasma Hcy levels were related to LV mass and ABI, after adjustment for covariates and creatinine. Significantly higher Hcy levels were found in patients with LVH (8.5 [4.4] vs 7.6 [2.8] μmol/L; adjusted P = .001) and ABI < 0.9 (10.4 [3.8] vs 7.9 [3.4] μmol/L; adjusted P = .001) than in those with LV mass and ABI within limits. Hcy levels were comparable between patients with and without carotid plaques, increased arterial stiffness, impaired endothelial, and LV pump function. Within markers of CV organ damage, only LVH was associated with a history of CVEs.

CONCLUSION

This study demonstrated an independent association between Hcy and LV mass as well as between LVH and a history of CVEs and suggests that LVH may represent 1 of the pathophysiologic links between Hcy and CV risk.

Factors Influencing Serum Homocysteine Levels in Postmenopausal Osteoporotic Females - Comparison to Urinary Collagen Crosslinks

Purpose: The correlation between serum levels of homocysteine and bone mineral density remains controversial. The aim of this study was to identify the potential factors associated with the levels of serum total homocysteine (S-Hcy) and urinary N-terminal telopeptide of type I collagen (U-NTX) in female osteoporotic patients. Materials and Methods: This cross-sectional study included 163 female osteoporotic patients, aged between 48 and 91 years, who had never been treated with anti-osteoporosis therapy. Background data including spine and hip bone mineral density, ongoing therapy for the metabolic disease, aortic calcification score as evaluated by lateral lumbar X-ray film, and recent fragility fracture history were obtained. S-Hcy, U-NTX levels, and creatinine clearance were measured. Results: Multiple linear regression analysis revealed a significant correlation between S-Hcy levels and aortic calcification score (p = 0.022), creatinine clearance (p = 0.004), and recent fracture history (within 1 year after fracture) (p = 0.028); conversely, U-NTX levels correlated significantly with total hip bone mineral density (p < 0.0001) and recent fracture history (p = 0.0007). Conclusions: S-Hcy levels had no correlation with bone mineral density, but were associated with the degree of aortic calcification, renal function, and fracture events. These confounding factors should be taken into consideration when the relationship between S-Hcy and bone mineral density is discussed.

Association between renal damage markers and carotid atherosclerosis in Afro-descendants with hypertension belonging to a minority ethnic group from Brazil

Ethnicity appears to play an important role in the prevalence and severity of hypertension, renal disease, and atherosclerosis. A cross-sectional study was conducted, including 206 Afro-descendants with hypertension, living in the remaining quilombo communities. These subjects underwent a carotid intima-media thickness (CIMT) assessment. The presence of renal injury was assessed by: (1) The glomerular filtration rate (GFR) estimated by the formula CKD-EPI using creatinine and cystatin C and (2) Albuminuria (ACR ≥30 mg/g). The Poisson distribution model was set with robust variance to identify factors associated with carotid atherosclerosis. The statistical analysis was performed using the Stata 12.0 software, adopting a significance level of 5%. Most subjects were women (61.65%); the average age was 61.32 (±12.44) years. Subjects (12.62%) were identified with GFR <60 mL/min/1.73 m2 and 22.8% with albuminuria. Patients (59.22%) presented with a high CIMT. In the adjusted regression model, age ≥60 years (PR: 1.232 [CI 95%:1.091-1.390], p value = .001), ACR ≥30 mg/g (PR: 1.176 [CI 95%: 1.007-1.373], p = .040), and GFR/CKD-EPI using cystatin C (PR: 1.250 [CI 95%: 1.004-1.557], p = .045) were independently associated with carotid atherosclerosis. The occurrence of atherosclerotic lesions was high in the studied group. Age, albuminuria, and GFR (estimated by the formula CKD-EPI using cystatin C) influenced the prevalence of carotid atherosclerosis.

Modification of erythropoietin structure by N-homocysteinylation affects its antiapoptotic and proliferative functions

Many patients under therapy with recombinant human erythropoietin (rhuEPO) show resistance to the treatment, an effect likely associated with the accumulation of tissue factors, especially in renal and cardiovascular diseases. Hyperhomocysteinemia due to high serum levels of homocysteine has been suggested among the risk factors in those pathologies. Its main effect is the N-homocysteinylation of proteins due to the interaction between the highly reactive homocysteine thiolactone (HTL) and lysine residues. The aim of this study was to evaluate the effect of N-homocysteinylation on the erythropoietic and antiapoptotic abilities of EPO, which can be a consequence of structural changes in the modified protein. We found that both cellular functions were altered in the presence of HTL-EPO. A decreased net positive charge of HTL-EPO was detected by capillary zone electrophoresis, while analysis of polyacrylamide gel electropherograms suggested formation of aggregates. Far-UV spectra, obtained by Circular Dichroism Spectroscopy, indicated a switch of the protein's secondary structure from α-helix to β-sheet structures. Results of Congo red and Thioflavin T assays confirm the formation of repetitive β-sheet structures, which may account for aggregates. Accordingly, Dynamic Light Scattering analysis showed a markedly larger radius of the HTL-EPO structures, supporting the formation of soluble oligomers. These structural changes might interfere with the conformational adaptations necessary for efficient ligand-receptor interaction, thus affecting the proliferative and antiapoptotic functions of EPO. The present findings may contribute to explain the resistance exhibited by patients with cardio-renal syndrome to treatment with rhuEPO, as a consequence of structural modifications due to protein N-homocysteinylation.

Aldosterone modulates blood homocysteine and cholesterol in coronary artery disease patients - a possible impact on atherothrombosis?

Aldosterone plays a key role in maintaining the homeostasis of the whole organism. Under some circumstances, aldosterone can contribute to the progression of cardiovascular diseases, including coronary artery disease. This study demonstrates that aldosterone associates negatively with some lipidogram parameters and positively with the concentration of homocysteine. These associations are characteristic for coronary artery disease and are not present in control subjects. The findings also indicate that in vitro aldosterone stimulates homocysteine production by rat adrenal glands, which may explain the associations observed with coronary artery disease. Moreover, we have found that aldosterone significantly modulates in vitro platelet reactivity to arachidonate and collagen - aldosterone increases the pro-aggregatory action of collagen, but decreases the pro-aggregatory potential of arachidonate. Therefore, the findings of these in vitro and ex vivo experiments indicate the existence of new pathways by which aldosterone modulates lipid- homocysteine- and platelet-dependent atherogenesis.

Association between normal or mildly reduced kidney function, cardiovascular risk and biomarkers for atherosclerosis: results from the ENCORE trial

Background

Moderate-to-severe kidney dysfunction is associated with atherosclerotic cardiovascular disease (ASCVD). Gradations of normal or mildly reduced kidney function may also associate with ASCVD risk.

Methods

We conducted a secondary analysis using baseline data from the Exercise and Nutritional Interventions for Cardiovascular Health (ENCORE) trial. Participants were sedentary, overweight and obese adults with unmedicated pre-hypertension or Stage I hypertension and an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m². The Pooled Cohorts Equations were used to estimate a 10-year risk for first ASCVD event. Carotid artery intima-media thickness (IMT) and brachial artery flow-mediated dilation (FMD) were measured to assess subclinical atherosclerosis and vascular endothelial function, respectively. Using linear regression, we examined the association between eGFR and ASCVD risk, IMT and FMD.

Results

Participants (N = 139) were predominantly women (65%), white (60%), with a mean age of 52.0 ± 9.6 years and mean eGFR of 89.1 ± 15.0 mL/min/1.73 m². Lower eGFR of 15 mL/min/1.73 m² was associated with higher ASCVD risk [b = −2.7% (95% confidence interval: −3.7, −1.8%), P < 0.001], higher IMT [b = 0.05 mm (0.03, 0.08 mm), P < 0.001] and lower FMD [b = −0.87% (−1.64, −0.11%), P = 0.026]. Compared with eGFR ≥90 mL/min/1.73 m², those with eGFR 60–89 mL/min/1.73 m² had higher mean ASCVD risk (7.6% versus 2.7%; P < 0.001), greater mean IMT (0.74 mm versus 0.66 mm; P < 0.001) and lower mean FMD (2.0% versus 3.7%; P = 0.026). After controlling for CVD risk factors, the association between eGFR and IMT remained significant (P < 0.001), and eGFR and FMD trended toward significance (P = 0.08).

Conclusions

Among overweight and obese adults with unmedicated high blood pressure and eGFR ≥60 mL/min/1.73 m², lower eGFR is associated with a greater 10-year risk for first ASCVD event, higher IMT and relatively impaired FMD.

Association between serum cystatin C levels and the severity or potential risk factors of acute ischemic stroke

OBJECTIVE

We sought to investigate whether serum cystatin C levels are correlated with either stroke severity or with potential risk factors of acute ischemic stroke.

METHODS

171 patients with acute ischemic stroke and 99 control subjects with minor, unrelated diseases with stroke were included in this retrospective study. Serum cystatin C levels were determined in all subjects. Serum concentrations of several vascular risk factors in stoke patients were determined by biochemical assays. The severity of strokes was scored via the National Institutes of Health Stroke Scale (NIHSS).

RESULTS

Serum cystatin C levels were significantly increased in patients with acute ischemic stroke compared with control subjects (1.26 ± 0.34 mg/L vs. 0.78 ± 0.24 mg/L, p < 0.001).When analyzed in quartiles of serum cystatin C levels, concentrations were low (<0.75 mM) for 5 stroke patients (2.92%), intermediate (0.75-1 mM) for 42 patients (24.56%), high (1-1.25 mM) for 45 patients (26.32%), and very high (>1.25 mM) for 79 patients (46.20%). However, serum cystatin C levels were not correlated with NIHSS scores, serum total cholesterol, high-density lipoprotein, low-density lipoprotein, apolipoprotein a, or apolipoprotein b levels. Further, serum cystatin C concentrations in stroke patients were not correlated with the presence of intracranial arterial stenosis, hypertension, or diabetes.

CONCLUSION

Our study suggests that there is a close relationship between cystatin C and acute ischemic stroke, independently of conventional risk factors. But the levels of cystatin C are not correlated with the stroke severity.

Effect of renal impairment on atherosclerosis: only partially mediated by homocysteine

BACKGROUND

Cardiovascular risk and plasma total homocysteine (tHcy) are high in patients with renal failure. High tHcy may account for a substantial part of the increased risk. We assessed mediation by tHcy of the association of estimated glomerular filtration rate (eGFR CKD/EPI) with carotid total plaque area (TPA) and carotid stenosis.

METHODS

TPA and carotid stenosis were measured by ultrasound. Multiple linear regression was used to assess the effects of eGFR and/or tHcy after adjustment for age, sex, systolic blood pressure (SBP), smoking, LDL, HDL and weight.

RESULTS

Complete data were available for 1967 patients. eGFR decreased, and TPA and total stenosis increased linearly with age. After adjustment [age, sex, SBP, smoking (in pack years), low-density lipoprotein (LDL), high-density lipoprotein (HDL) and weight], eGFR and tHcy were independently associated with TPA (P < 0.01), but when both were added to the model, their significance was attenuated (P = 0.06 for eGFR, 0.03 for tHcy). Mediation analysis showed that tHcy seems to contribute to a significant mediation of the association of eGFR with TPA but not stenosis; after adjustment for the set of risk factors listed above, tHcy still demonstrated significant mediation on TPA (P = 0.03), but not on stenosis (P = 0.16).

CONCLUSIONS

tHcy accounts for a significant part, but not all of the effect of renal impairment on atherosclerosis. Other uremic toxins including metabolic products of the intestinal microbiome may explain residual effects of renal failure on atherosclerosis. Therapeutic approaches arising from that hypothesis are discussed.

Metagenomic sequencing reveals altered metabolic pathways in the oral microbiota of sailors during a long sea voyage

Seafaring is a difficult occupation, and sailors face higher health risks than individuals on land. Commensal microbiota participates in the host immune system and metabolism, reflecting the host's health condition. However, the interaction mechanisms between the microbiota and the host's health condition remain unclear. This study reports the influence of long sea voyages on human health by utilising a metagenomic analysis of variation in the microbiota of the buccal mucosa. Paired samples collected before and after a sea-voyage were analysed. After more than 120 days of ocean sailing, the oral microbial diversity of sailors was reduced by approximately 5 fold, and the levels of several pathogens (e.g., Streptococcus pneumonia) increased. Moreover, 69.46% of the identified microbial sequences were unclassified microbiota. Notably, several metabolic pathways were dramatically decreased, including folate biosynthesis, carbohydrate, lipid and amino acid pathways. Clinical examination of the hosts confirmed the identified metabolic changes, as demonstrated by decreased serum levels of haemoglobin and folic acid, a decreased neutrophil-to-lymphocyte ratio, and increased levels of triglycerides, cholesterol and homocysteine, which are consistent with the observed microbial variation. Our study suggests that oral mucosal bacteria may reflect host health conditions and could provide approaches for improving the health of sailors.

Guidelines for the primary prevention of stroke: a statement for healthcare professionals from the American Heart Association/American Stroke Association

The aim of this updated statement is to provide comprehensive and timely evidence-based recommendations on the prevention of stroke among individuals who have not previously experienced a stroke or transient ischemic attack. Evidence-based recommendations are included for the control of risk factors, interventional approaches to atherosclerotic disease of the cervicocephalic circulation, and antithrombotic treatments for preventing thrombotic and thromboembolic stroke. Further recommendations are provided for genetic and pharmacogenetic testing and for the prevention of stroke in a variety of other specific circumstances, including sickle cell disease and patent foramen ovale.

Pathogenesis and treatment of atherosclerosis in lupus

The prevalence of atherosclerosis (ATH) is higher in patients with systemic lupus erythematosus (SLE) and occurs at an earlier age. The lupus-related factors that account for this increased risk are likely numerous and related to the factors described in this article. Identifying of at-risk subjects and increasing the understanding of pathogenesis of ATH in SLE is critical for improving the quality of care and improving mortality in this vulnerable population.

Common genetic loci influencing plasma homocysteine concentrations and their effect on risk of coronary artery disease

BACKGROUND

The strong observational association between total homocysteine (tHcy) concentrations and risk of coronary artery disease (CAD) and the null associations in the homocysteine-lowering trials have prompted the need to identify genetic variants associated with homocysteine concentrations and risk of CAD.

OBJECTIVE

We tested whether common genetic polymorphisms associated with variation in tHcy are also associated with CAD.

DESIGN

We conducted a meta-analysis of genome-wide association studies (GWAS) on tHcy concentrations in 44,147 individuals of European descent. Polymorphisms associated with tHcy (P < 10(⁻⁸) were tested for association with CAD in 31,400 cases and 92,927 controls.

RESULTS

Common variants at 13 loci, explaining 5.9% of the variation in tHcy, were associated with tHcy concentrations, including 6 novel loci in or near MMACHC (2.1 × 10⁻⁹), SLC17A3 (1.0 × 10⁻⁸), GTPB10 (1.7 × 10⁻⁸), CUBN (7.5 × 10⁻¹⁰), HNF1A (1.2 × 10⁻¹²)), and FUT2 (6.6 × 10⁻⁹), and variants previously reported at or near the MTHFR, MTR, CPS1, MUT, NOX4, DPEP1, and CBS genes. Individuals within the highest 10% of the genotype risk score (GRS) had 3-μmol/L higher mean tHcy concentrations than did those within the lowest 10% of the GRS (P = 1 × 10⁻³⁶). The GRS was not associated with risk of CAD (OR: 1.01; 95% CI: 0.98, 1.04; P = 0.49).

CONCLUSIONS

We identified several novel loci that influence plasma tHcy concentrations. Overall, common genetic variants that influence plasma tHcy concentrations are not associated with risk of CAD in white populations, which further refutes the causal relevance of moderately elevated tHcy concentrations and tHcy-related pathways for CAD.

Sustained activation of N-methyl-D-aspartate receptors in podoctyes leads to oxidative stress, mobilization of transient receptor potential canonical 6 channels, nuclear factor of activated T cells activation, and apoptotic cell death

Atypical N-methyl-D-aspartate (NMDA) receptors are expressed in podocytes. Sustained (≥24 h) application of 50 to100 μM NMDA to immortalized mouse podocytes evoked a marked increase in the production of reactive oxygen species(ROS) such as H₂O₂. This effect of NMDA was associated with increased cell-surface expression of p47(phox), a cytosolic regulatory subunit of the NADPH oxidase NOX2. NMDA-evoked generation of ROS drove an increase in steady-state surface expression of transient receptor potential canonical (TRPC) 6 channels, which was blocked by the NMDA antagonist dizocilpine(MK-801) and by a membrane-permeable scavenger of ROS. The effect of NMDA on TRPC6 was observed using cell surface biotinylation assays and also with whole-cell recordings made under conditions designed to facilitate detection of current through TRPC6. NMDA mobilization of TRPC6 channels was blocked by concurrent treatment with the NMDA antagonist MK-801 and by a membrane-permeable scavenger ofROS. Mobilization of TRPC6 was also evoked by L-homocysteic acid. NMDA treatment also increased nuclear localization of endogenous nuclear factor of activated T cells, which could be blocked by MK-801, by scavenging ROS, by the calcineurin inhibitor cyclosporine, and by the TRPC channel inhibitor 1-[2-(4-methoxyphenyl)-2-[3-(4-methoxyphenyl)propoxy]ethyl]imidazole (SKF-96365). NMDA treatment also evoked robust activation of Rho but not Rac,consistent with previous studies of downstream effectors of TRPC6 activation. Exposing cells to NMDA for 24 h reduced total and cell surface expression of the podocyte markers nephrin and podocin, but there was no loss of cells. With longer NMDA exposure (72 h), we observed loss of cells associated with nuclear fragmentation and increased expression of caspase-3, caspase-6, and Bax, suggesting an apoptotic process.

The effect of folic acid based homocysteine lowering on cardiovascular events in people with kidney disease: systematic review and meta-analysis

OBJECTIVE

To systematically review the effect of folic acid based homocysteine lowering on cardiovascular outcomes in people with kidney disease.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, the Cochrane Library, and ClinicalTrials.gov to June 2011.

STUDY SELECTION

Randomised trials in people with non-dialysis dependent chronic kidney disease or end stage kidney disease or with a functioning kidney transplant reporting at least 100 patient years of follow-up and assessing the effect of folic acid based homocysteine lowering therapy. No language restrictions were applied.

DATA EXTRACTION

Two reviewers independently extracted data on study setting, design, and outcomes using a standardised form. The primary endpoint was cardiovascular events (myocardial infarction, stroke, and cardiovascular mortality, or as defined by study author). Secondary endpoints included the individual composite components, all cause mortality, access thrombosis, requirement for renal replacement therapy, and reported adverse events, including haematological and neurological events. The effect of folic acid based homocysteine lowering on outcomes was assessed with meta-analysis using random effects models.

RESULTS

11 trials were identified that reported on 4389 people with chronic kidney disease, 2452 with end stage kidney disease, and 4110 with functioning kidney transplants (10,951 participants in total). Folic acid based homocysteine therapy did not prevent cardiovascular events (relative risk 0.97, 95% confidence interval 0.92 to 1.03, P = 0.326) or any of the secondary outcomes. There was no evidence of heterogeneity in subgroup analyses, including those of kidney disease category, background fortification, rates of pre-existing disease, or baseline homocysteine level. The definitions of chronic kidney disease varied widely between the studies. Non-cardiovascular events could not be analysed as few studies reported these outcomes.

CONCLUSIONS

Folic acid based homocysteine lowering does not reduce cardiovascular events in people with kidney disease. Folic acid based regimens should not be used for the prevention of cardiovascular events in people with kidney disease.

Accelerated atherosclerosis in patients with SLE--mechanisms and management

Rapid-onset cardiovascular disease (CVD) is a major concern for many patients with systemic lupus erythematosus (SLE). Cardiovascular events occur more frequently and with earlier onset in patients with SLE compared with healthy individuals. Traditional risk factors, such as altered lipid levels, aging and smoking, do not fully explain this increased risk of CVD, strongly suggesting that autoimmunity contributes to accelerated atherosclerosis. Altered immune system function is recognized as the primary contributor to both the initiation and progression of atherosclerosis. Multiple manifestations of autoimmunity, including changes in cytokine levels and innate immune responses, autoantibodies, adipokines, dysfunctional lipids, and oxidative stress, could heighten atherosclerotic risk. In addition, multiple SLE therapeutics seem to affect the development and progression of atherosclerosis both positively and negatively. SLE-specific cardiovascular risk factors are beginning to be discovered by several groups, and development of a comprehensive, clinically feasible biomarker panel could be invaluable for identification and treatment of patients at risk of developing accelerated atherosclerosis. Here, we discuss the epidemiology of CVD in SLE and the implications of immune system dysfunction on the development and progression, monitoring and treatment of atherosclerosis in individuals with this disease.

Effect of folic acid supplementation on cardiovascular outcomes: a systematic review and meta-analysis

BACKGROUND

Folic acid is widely used to lower homocysteine concentrations and prevent adverse cardiovascular outcomes. However, the effect of folic acid on cardiovascular events is not clear at the present time. We carried out a comprehensive systematic review and meta-analysis to assess the effects of folic acid supplementation on cardiovascular outcomes.

METHODOLOGY AND PRINCIPAL FINDINGS

We systematically searched Medline, EmBase, the Cochrane Central Register of Controlled Trials, reference lists of articles, and proceedings of major meetings for relevant literature. We included randomized placebo-controlled trials that reported on the effects of folic acid on cardiovascular events compared to placebo. Of 1594 identified studies, we included 16 trials reporting data on 44841 patients. These studies reported 8238 major cardiovascular events, 2001 strokes, 2917 myocardial infarctions, and 6314 deaths. Folic acid supplementation as compared to placebo had no effect on major cardiovascular events (RR, 0.98; 95% CI, 0.93-1.04), stroke (RR, 0.89; 95% CI,0.78-1.01), myocardial infarction (RR, 1.00; 95% CI, 0.93-1.07), or deaths from any cause (RR, 1.00;95% CI, 0.96-1.05). Moreover, folic acid as compared to placebo also had no effect on the following secondary outcomes: risk of revascularization (RR, 1.05; 95%CI, 0.95-1.16), acute coronary syndrome (RR, 1.06; 95%CI, 0.97-1.15), cancer (RR, 1.08; 95%CI, 0.98-1.21), vascular death (RR, 0.94; 95%CI,0.88-1.02), or non-vascular death (RR, 1.06; 95%CI, 0.97-1.15).

CONCLUSION/SIGNIFICANCE

Folic acid supplementation does not effect on the incidence of major cardiovascular events, stroke, myocardial infarction or all cause mortality.

Correction of endothelial dysfunction after selective homocysteine lowering gene therapy reduces arterial thrombogenicity but has no effect on atherogenesis

Hyperhomocysteinemia is an independent risk factor for ischemic cardiovascular diseases, but its causal role in atherothrombosis remains controversial. Proatherogenic and/or prothrombotic effects may underlie the potential causal relation between hyperhomocysteinemia and cardiovascular events. Here, the effects of selective lowering of plasma homocysteine, plasma cholesterol, or both on endothelial function and on atherogenesis in male hyperlipidemic and hyperhomocysteinemic C57BL/6 low-density lipoprotein receptor (LDLr)(-/-)/cystathionine-β-synthase (CBS)(+/-)-deficient mice were investigated. Second, we evaluated whether selective homocysteine lowering has anti-thrombotic effects in a model of arterial thrombosis. A hyperhomocysteinemic and atherogenic diet was started at the age of 12 weeks. Three weeks later, gene transfer was performed with E1E3E4-deleted adenoviral vectors for hepatocyte-restricted overexpression of CBS (AdCBS) or of the LDLr (AdLDLr), or with the control vector Adnull. In a fourth group, AdCBS and AdLDLr were co-administered. Selective homocysteine lowering but not selective cholesterol lowering restored endothelial function at 6 weeks after gene transfer. Intimal area in the aortic root and in the brachiocephalic artery at 13 weeks was more than 100-fold (p < 0.001) smaller in AdLDLr and AdCBS/AdLDLr mice than in control mice and AdCBS mice. No differences in intimal area were observed between control mice and AdCBS mice. In a model of carotid artery thrombosis, the average time to first occlusion and to stable occlusion were 1.9-fold (p < 0.01) and 2.1-fold longer (p < 0.01), respectively, in AdCBS-treated mice than in control mice. Taken together, these data show that correction of endothelial dysfunction following selective homocysteine lowering has anti-thrombotic but no anti-atherogenic effects.

The relationship of cardiovascular risk factors to Alzheimer disease in Choctaw Indians

OBJECTIVES

To test the hypothesis that cardiovascular risk factors (CRFs) influence predisposition to and the clinical course of Alzheimer disease (AD), the authors compared Choctaw Indians, a group with known high CRF with white persons with AD. In addition to CRF history, the authors investigated the frequency of apolipoprotein E4 (apoE4) genotype andplasma homocysteine (HC) levels.

METHOD

The authors compared 39 Choctaw Indians with AD and 39 Choctaw Indians without AD to 39 white persons with AD with all groups similar in age. CRF history included diabetes, hypertension, high cholesterol or hypolipidemic agent use, or myocardial infarction. The authors also compared plasma HC concentration and apoE4 allele frequency.

RESULTS

Choctaw persons with AD differed significantly from white persons with AD in history of hypertension, diabetes, and in HC values but not from Indians without AD. There was a significantly lower apoE4 allele frequency in Choctaw Indian AD than white persons with AD, and both AD groups had an affected first degree relative significantly more often than Indian controls. There was no relationship between the number of CRF and age at onset among Indians or whites, whereas HC concentration was associated with significantly earlier age of onset for Choctaw Indians but not for whites.

CONCLUSIONS

This small study suggests that in Choctaw Indians modifiable risk factors may play more of a role in disease pathogenesis than in whites and that nonmodifiable risk factors such as apoE4 may play less of a role.

Pronounced association of elevated serum homocysteine with stroke in subgroups of individuals: a nationwide study

BACKGROUND

Although the original homocysteine hypothesis for atherothrombotic disease is falling out of favor, prior studies did not comprehensively adjust for confounders or explore specific subgroups of patients who may benefit from serum homocysteine-lowering. We aimed to determine (1) if elevated total homocysteine (tHcy) affects odds of prevalent stroke after adjusting for a broad array of pertinent covariates and (2) whether particular vascular risk factors amplify the effect of high homocysteine on prevalent stroke.

METHODS

The independent and interactive effects of elevated tHcy (≥10 μmol/L) on likelihood of prevalent stroke was assessed in the National Health and Nutrition Examination Survey, a nationally representative cross-sectional sample of the US population conducted from 1999 to 2004 (n=12,683).

RESULTS

After adjusting for 17 covariates, those with elevated tHcy were more likely to have prevalent stroke vs. those without elevated tHcy (OR 1.52, 95% CI 1.01-2.29; p=0.045). Individuals with a combination of elevated tHcy and hypertension were substantially more likely to have prevalent stroke compared to individuals without either condition (OR 12.02, 95% CI 6.36-22.73 for men and OR 17.34, 95% CI 10.49-28.64 for women). The association of tHcy with prevalent stroke was strongest in younger individuals and declined linearly with increasing age.

CONCLUSIONS

Elevated tHcy independently increases odds of prevalent stroke. Younger individuals and those with concomitant hypertension may particularly benefit from tHcy-lowering.

Guidelines for the primary prevention of stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

BACKGROUND AND PURPOSE

This guideline provides an overview of the evidence on established and emerging risk factors for stroke to provide evidence-based recommendations for the reduction of risk of a first stroke.

METHODS

Writing group members were nominated by the committee chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association (AHA) Stroke Council Scientific Statement Oversight Committee and the AHA Manuscript Oversight Committee. The writing group used systematic literature reviews (covering the time since the last review was published in 2006 up to April 2009), reference to previously published guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and when appropriate, formulate recommendations using standard AHA criteria (Tables 1 and 2). All members of the writing group had the opportunity to comment on the recommendations and approved the final version of this document. The guideline underwent extensive peer review by the Stroke Council leadership and the AHA scientific statements oversight committees before consideration and approval by the AHA Science Advisory and Coordinating Committee.

RESULTS

Schemes for assessing a person's risk of a first stroke were evaluated. Risk factors or risk markers for a first stroke were classified according to potential for modification (nonmodifiable, modifiable, or potentially modifiable) and strength of evidence (well documented or less well documented). Nonmodifiable risk factors include age, sex, low birth weight, race/ethnicity, and genetic predisposition. Well-documented and modifiable risk factors include hypertension, exposure to cigarette smoke, diabetes, atrial fibrillation and certain other cardiac conditions, dyslipidemia, carotid artery stenosis, sickle cell disease, postmenopausal hormone therapy, poor diet, physical inactivity, and obesity and body fat distribution. Less well-documented or potentially modifiable risk factors include the metabolic syndrome, excessive alcohol consumption, drug abuse, use of oral contraceptives, sleep-disordered breathing, migraine, hyperhomocysteinemia, elevated lipoprotein(a), hypercoagulability, inflammation, and infection. Data on the use of aspirin for primary stroke prevention are reviewed.

CONCLUSIONS

Extensive evidence identifies a variety of specific factors that increase the risk of a first stroke and that provide strategies for reducing that risk.

The relationship of cystatin C, creatinine, estimated GFR, and cardiovascular events

This study examined the predictive value of plasma cystatin C, creatinine and estimated glomerular filtration rate (eGFR) as risk factors for cardiovascular disease in Chinese. Plasma cystatin C and creatinine were measured in 466 coronary heart disease (CHD) patients recruited from 4 hospitals and 349 healthy controls from local communities in Wuhan, China. Cockroft-Gault formula was used to estimate the glomerular filtration rate (GFR) after adjusting for body surface area. With each measure, the study population was divided into quintiles. The results showed that the patients had significantly higher levels of plasma cystatin C, creatinine, and lower level of eGFR than controls. Lower eGFR was associated with a higher risk of cardiovascular events. As compared with the first (highest) quintile, the hazard ratios (and 95% CIs) after multivariate adjustment for CHD were as follows: third quintile, 2.98 (1.54-5.78); fourth quintile, 3.34 (1.58-7.09); fifth quintile, 4.37(1.84-10.35). With higher cystatin C quintiles (≥1.00 mg/L and ≥1.17 mg/L), the hazard ratios for CHD were 2.16 (1.23-3.81) and 2.34 (1.25-4.38), similar to those of creatinine 2.21 (1.21-4.03) and 2.03 (1.07-3.84). However, it was plasma cystatin C not eGFR or creatinine had stronger association with ischemic stroke. The highest quintile had the hazard ratio of 4.51 (1.45-14.08) after multivariate adjustment. It was concluded that plasma cystatin C, associated with renal function, is not an independent risk factor for cardiovascular disease. eGFR is a better risk predictor for CHD than plasma cystatin C and creatinine. But for ischemic stroke, plasma cystatin C is a better risk factor than creatinine and estimated GFR.

Early stage detection of conduit artery endothelial dysfunction in patients with type 1 diabetes

Flow-mediated dilatation evaluation using hand skin heating may possibly be more accurate than post-ischaemic hyperaemia to detect conduit artery endothelial dysfunction in type 1 diabetes. We measured in 24 type 1 diabetic patients (n=16 without microangiopathy) and 24 healthy matched subjects radial artery diameter (echotracking), blood flow and mean wall shear stress during heating and post-ischaemic hyperaemia. Compared with controls, flow-mediated dilatation was lower in diabetic patients during post-ischaemic hyperaemia and heating. However, in the subgroup of uncomplicated patients, a decreased flow-mediated dilatation was only apparent during heating (17.1+/-1.6% vs. 24.3+/-0.7%, p<0.05) but not during post-ischaemic hyperaemia (10.1+/-1.1% vs. 10.5+/-0.6%, NS). This was confirmed by the lower slope of the diameter-mean wall shear stress relationship in these patients in the absence of modification in endothelium-independent dilatation. We conclude that hand skin heating permits the early detection of conduit artery endothelial dysfunction in type 1 diabetic patients with normal response to post-ischaemic hyperaemia. This procedure could be useful to investigate the prognostic role of vascular dysfunction and the impact of vasculoprotective treatments in this patient population.

Management of cardiovascular complications in systemic lupus erythematosus

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Patients with SLE have an excess risk compared with the general population; this is particularly pronounced in younger women with SLE who have an excess risk of over 50-fold compared with population controls. There is a higher prevalence of subclinical atherosclerosis in patients with SLE compared with controls, as demonstrated by a variety of imaging modalities discussed in this review. The causality of the excess risk of CVD and subclinical atherosclerosis is multifactorial in patients with SLE. While traditional risk factors play a role, after controlling for the traditional Framingham risk factors, the excess risk is still 7.5-fold greater than the general population. This review will also cover novel cardiovascular risk factors and some SLE-specific variables that contribute to CVD risk. This review discusses the risk factor modification and the evidence available for treatment of these risk factors in SLE. There have not yet been any published randomized, controlled trials in patients with SLE with respect to CVD risk factor modifications. Thus, the treatment and management recommendations are based largely on published guidelines for other populations at high risk for CVD.

Hyperhomocysteinemia in uremia--a red flag in a disrupted circuit

Hyperhomocysteinemia is an independent cardiovascular risk factor, according to most observational studies and to studies using the Mendelian randomization approach, utilizing the common polymorphism C677T of methylene tetrahydrofolate reductase. In contrast, the most recent secondary preventive intervention studies, in the general population and in chronic kidney disease (CKD) and uremia, which are all negative (with the possible notable exception of stroke), point to other directions. However, all trials use folic acid in various dosages as a means to reduce homocysteine levels, with the addition of vitamins B6 and B12. It is possible that folic acid has negative effects, which offset the benefits; alternatively, homocysteine could be an innocent by-stander, or a surrogate of the real culprit. The latter possibility leads us to the search for potential candidates. First, the accumulation of homocysteine in blood leads to an intracellular increase of S-adenosylhomocysteine (AdoHcy), a powerful competitive methyltransferase inhibitor, which by itself is considered a predictor of cardiovascular events. DNA methyltransferases are among the principal targets of hyperhomocysteinemia, as studies in several cell culture and animal models, as well as in humans, show. In CKD and in uremia, hyperhomocysteinemia and high intracellular AdoHcy are present and are associated with abnormal allelic expression of genes regulated through methylation, such as imprinted genes, and pseudoautosomal genes, thus pointing to epigenetic dysregulation. These alterations are susceptible to reversal upon homocysteine-lowering therapy obtained through folate administration. Second, it has to be kept in mind that homocysteine is mainly protein-bound, and its effects could be linked therefore to protein homocysteinylation. In this respect, increased protein homocysteinylation has been found in uremia, leading to alterations in protein function.

Cystatin C levels in plasma and peripheral blood mononuclear cells among hyperhomocysteinaemic subjects: effect of treatment with B-vitamins

Homocysteine has been related to increased risk of CVD. Matrix degradation and inflammation may be involved in this link between hyperhomocysteinaemia and CVD. Recent studies suggest that cystatin C can modulate matrix degradation and inflammation. The present study measured cystatin C at protein (plasma) and mRNA levels (peripheral blood mononuclear cells (PBMC)) in hyperhomocysteinaemic individuals (n 37, female seven and male thirty, aged 20–70 years) before and after B-vitamin supplementation for 3 months in a randomised, placebo-controlled double-blind trial. In a cross-sectional study, seventeen of the hyperhomocysteinaemic subjects were age- and sex-matched to healthy controls (n 17). Our main findings were: (i) as compared with controls, hyperhomocysteinaemic subjects tended to have higher plasma concentrations of cystatin C and lower mRNA levels of cystatin C in PBMC; (ii) compared with placebo, treatment of hyperhomocysteinaemic individuals with B-vitamins significantly increased plasma levels of cystatin C and mRNA levels of cystatin C in PBMC; (iii) while plasma levels of cystatin C were positively correlated with plasma levels of TNF receptor-1, mRNA levels of cystatin C in PBMC were inversely correlated with this TNF parameter. Taken together, our findings suggest that disturbed cystatin C levels may be a characteristic of hyperhomocysteinaemic individuals, potentially related to low-grade systemic inflammation in hyperhomocysteinaemic subjects, and that B-vitamins may modulate cystatin C levels in these individuals.

Plasma folate and total homocysteine levels are associated with the risk of myocardial infarction, independently of each other and of renal function

OBJECTIVES

To investigate the relationship between plasma folate, vitamin B12 and total homocysteine concentrations, dietary intake of folate and vitamins B12, B6 and B2, and the risk of first acute myocardial infarction (MI).

DESIGN

Nested case-referent study with up to 13 years of follow-up.

SETTING

The population-based Northern Sweden Health and Disease Study, with 73 879 participants at the time of case ascertainment.

SUBJECTS

A total of 571 MI cases (406 men) and 1569 matched referents. Of the cases, 530 had plasma samples available, and 247 had dietary B-vitamin intake data.

RESULTS

Plasma concentrations of folate were inversely associated, and total homocysteine positively associated, with the risk of MI, independently of each other and of a number of established and novel cardiovascular risk factors, including renal function [multivariate odds ratio for highest vs. lowest quintile of folate 0.52 (95% CI 0.31-0.84), P for trend = 0.036, and homocysteine 1.92 (95% CI 1.20-3.09), P for trend = 0.006]. For plasma vitamin B12 concentrations, and vitamin B12, B6 and B2 intake, no clear risk relationship was apparent. Though not statistically significant, the results for folate intake were consistent with those for plasma concentrations.

CONCLUSIONS

In this large prospective study of a population without mandatory folic acid fortification, both folate and homocysteine were strongly associated with the risk of myocardial infarction, independently of each other and of renal function. Although randomized trials of folic acid supplementation are needed to determine causality, our findings highlight the potential importance of folate, or sources of folate, in incident cardiovascular disease.

Identification of ZNF366 and PTPRD as novel determinants of plasma homocysteine in a family-based genome-wide association study

Total plasma homocysteine concentration (tHcy) is a biomarker for atherothrombotic disease, but causality remains uncertain. Polymorphisms in the genes involved in methionine metabolism explain only a small fraction of the heritability of tHcy levels. In a genome-wide association study, we examined the genetic determinants of tHcy using a 2-stage design. First, 283 437 single nucleotide polymorphisms (SNPs) were tested for association with tHcy in 387 persons recruited from 21 large Spanish families. Of those, 17 SNPs showed equal or stronger association with tHcy level compared with the MTHFR 677C>T SNP (beta = 0.10, P = .0001). Second, a replication analysis of these 17 SNPs was performed in patients with premature myocardial infarction (n = 1238). Novel associations were found for SNPs near the ZNF366 gene (lead SNP rs7445013; discovery stage: adjusted beta = -0.12, P = 5.30 x 10(-6), replication stage: adjusted beta = -0.13, P = .004) and the PTPRD gene (lead SNP rs973117; discovery stage: adjusted beta = 0.11, P = 5.5 x 10(-6), replication stage: adjusted beta = 0.10, P = .005). These associations were independent of known confounders, including creatinine clearance and plasma fibrinogen concentration. Our findings implicate novel pathways in homocysteine metabolism, and highlight the need for investigation of the associated genes in the etiology of vascular diseases.

The impact of eNOS, MTR and MTHFR polymorphisms on renal graft survival in children and young adults

BACKGROUND

The main cause of reduced long-term graft survival is chronic allograft injury. Cardiovascular risk factors such as hyperhomocysteinaemia, accumulation of asymmetric dimethylarginine, increased oxidative stress and decreased production of nitric oxide seem to play an important role. Functional polymorphisms of the endothelial isoform of nitric oxide synthase (NOS) gene cause an alteration in nitric oxide production. Nitric oxide levels, and thus oxidative stress, are also influenced by hyperhomocysteinaemia.

METHODS

We carried out a genetic analysis of endothelial nitric oxide synthase (eNOS) 894G>T, methionine synthase (MTR) 2756A>G and methylenetetrahydrofolate reductase (MTHFR) 677C>T/1298A>C in 268 renal allograft recipient/donor (D/R) matches, with respect to long-term graft survival.

RESULTS

While MTHFR 677C>T/1298A>G and MTR 2756A>G polymorphism distribution in both recipients (R) and donors (D) showed no significant difference between matches with loss of graft function and those with long-term graft survival, the frequency of the eNOS 894TT genotype of donors was significantly increased (P = 0.040) in matches with better graft survival. The multivariate analysis identified the eNOS 894 genotype and clinically acute rejection episodes as independent risk factors for graft loss (P = 0.0406 and P = 0.0093, respectively).

CONCLUSIONS

The association between eNOS 894G>T polymorphism of donors and graft survival seems to suggest a role for this gene in chronic allograft injury; however, further studies are needed to confirm this hypothesis.