Association of plasma homocysteine with the number of major coronary arteries severely narrowed

Association between homocysteine and coronary artery disease-trend over time and across the regions: a systematic review and meta-analysis

BACKGROUND

The association of homocysteine with coronary artery disease (CAD) has been explored previously with mixed findings. The present Systematic Review and Meta-Analysis (SRMA) has assessed the pooled estimate of association between homocysteine (Hcy) and CAD, and its variation over the period and geography.

METHODS

Systematic literature search was done in PubMed, Scopus and Cochrane to identify the observational studies that have reported mean Hcy among cases (CAD) and control. The SRMA was registered in PROSPERO (ID-CRD42023387675).

RESULTS

Pooled standardized mean difference (SMD) of Hcy levels between the cases and controls was 0.73 (95% CI 0.55-0.91) from 59 studies. Heterogeneity was high (I2 94%). The highest SMD was found among the Asian studies (0.85 [95% CI 0.60-1.10]), while the European studies reported the lowest SMD between the cases and controls (0.32 [95% CI 0.18-0.46]). Meta-regression revealed that the strength of association was increasing over the years (Beta = 0.0227, p = 0.048).

CONCLUSIONS

Higher homocysteine levels might have a significant association with coronary artery diseases, but the certainty of evidence was rated low, owing to the observational nature of the studies, high heterogeneity, and publication bias. Within the population groups, Asian and African populations showed a greater strength of association than their European and American counterparts, and it also increased over the years.

Correlation of Homocysteine Level and Age in Patients with Ischemic Stroke

Introduction

Hyperhomocysteinemia is associated with atherosclerosis, as it can be seen in inborn errors of methionine metabolism. Likewise, many studies have also reported more modest increases in serum homocysteine levels in other atherosclerotic disorders like cardiovascular disease and all types of stroke with a positive correlation with age. But overall literature is controversial. Therefore, this study is being conducted to further investigate the relationship between homocysteine ​​levels and age in patients, especially those with ischemic stroke.

Material and methods

This cross-sectional study is conducted at a major hospital in Karachi in which all patients with ischemic stroke, diagnosed within 24 hours on CT, and age 40-75 years of both genders were enrolled for six months. Other demographics were also noted like gender, smoking status, and comorbidities (diabetes mellitus [DM], hypertension [HTN]). The homocysteine level was also checked by collecting non-fasting blood. Vitamin B12 level was not checked. The age, weight, height, body mass index (BMI), and homocysteine level’s means and standard deviations and the gender, DM, hypertension, and smoking status frequencies and percentages were calculated. The correlation coefficient of homocysteine level and age was also calculated. Stratification was done to see the effects of gender, BMI, DM, and HTN on homocysteine levels by applying the chi-square test.

Results

The mean age of the patients was 55.60 ± 11.45 years. Gender distribution showed that 111 (62.40%) patients were male, and 67 (37.60%) patients were female. Diabetic, hypertensive, and smoking status of the patients was 58 (32.60%), 96 (53.90%), and 53 (29.80%), respectively. The mean homocysteine level was 14.61, with a standard deviation of 1.47. Pearson’s correlation test showed that there is no statistically significant correlation between homocysteine levels and age. But a significant linear relationship was found of homocysteine levels with DM and HTN. 

Conclusion

Further investigation of the relationship of homocysteine ​​levels with age, diabetes mellitus, and hypertension, and the role of homocysteine as a risk factor for ischemic stroke should be carried out on a larger scale to prove its accuracy. The benefits of screening for homocysteine ​​levels also need to be studied in the elderly, especially those with diabetes mellitus and hypertension, which can lead to timely prevention of strokes and ischemic heart disease with vitamin B supplements, and other appropriate interventions.

Association of Hyperhomocysteinemia with Increased Coronary Microcirculatory Resistance and Poor Short-Term Prognosis of Patients with Acute Myocardial Infarction after Elective Percutaneous Coronary Intervention

Background

This study aims to investigate the coronary microcirculatory resistance and prognosis of patients with acute myocardial infarction (AMI) concomitant with hyperhomocysteinemia (HHcy) after an elective percutaneous coronary intervention (PCI).

Methods

A total of 101 patients that underwent elective PCI between May 2015 and July 2018 due to AMI were consecutively enrolled in this study. Patients were divided into a HHcy group (53) and a normal Hcy group (control; 48) based on their plasma homocysteine concentration. The characteristics of coronary angiography, the index of microcirculatory resistance (IMR) of infarct-related vessels (IRV), changes in left ventricular end diastolic diameter (LVEDd) and left ventricular ejection fraction (LVEF) before and after PCI, and the incidence of major adverse cardiovascular events (MACE) three months after PCI were compared between these groups.

Results

Compared to the results from the Hcy group, the HHcy group had a higher IMR. The HHcy group had significantly higher LVEDd and a lower LVEF than the Hcy group 3 months after PCI. Additionally, the incidence of MACE at three months after PCI was higher in the HHcy group than in the Hcy group. Pearson correlation analysis revealed a positive correlation with IMR in the HHcy group. Furthermore, there was a difference in the LVEDd measured at one day after PCI and at three months after PCI in the HHcy group.

Conclusion

AMI patients concomitant with HHcy that undergo elective PCI are prone to coronary microcirculatory dysfunction and have a poor cardiac function and poor prognosis at three months after PCI.

Upregulation of microRNA-218 reduces cardiac microvascular endothelial cells injury induced by coronary artery disease through the inhibition of HMGB1

This study is performed to examine the impacts of microRNA-218 (miR-218) on cardiac microvascular endothelial cells (CMECs) injury induced by coronary artery disease (CAD). Reverse-transcription quantitative polymerase chain reaction (RT-qPCR) was applied for detecting miR-218 expression in serum of patients with CAD and healthy controls, and the correlation between miR-218 expression and the clinical indexes such as creatine kinase, creatine kinase-myocardial band, cardiac troponin I, and coronary Gensini score was analyzed. CMECs were coincubated with homocysteine for 24 hr for CMECs injury, and the cells were transfected with miR-218 mimics or miR-218 inhibitors. Besides, we used oxidized low density lipoprotein as an inducer to incubate with CMECs for 24 hr, and the model of CMECs injury was established to be transfected with miR-218 mimics. RT-qPCR and western blot analysis were used to detect miR-218 and HMGB1 expression in CMECs. A series of experiments were used to determine cell proliferation, apoptosis, migration, and angiogenesis ability of CMECs. Vascular endothelial growth factor expression and inflammatory factor contents were measured. The obtained results suggested that miR-218 expression in peripheral blood of patients with CAD descended substantially versus that of healthy controls. Low miR-218 expression was found in CAD-induced CMECs injury. Overexpressed miR-218 promoted the proliferation, migration, angiogenesis ability, induced apoptosis, and alleviated the inflammatory injury of CAD-induced CMECs. miR-218 may negatively regulate the expression of HMGB1 in CAD. This study demonstrates that upregulation of miR-218 reduces CMECs injury induced by CAD through the inhibition of HMGB1.

Homocysteine and age-associated disorders

There are numerous theories of aging, a process which still seems inevitable. Aging leads to cancer and multi-systemic disorders as well as chronic diseases. Decline in age- associated cellular functions leads to neurodegeneration and cognitive decline that affect the quality of life. Accumulation of damage, mutations, metabolic changes, failure in cellular energy production and clearance of altered proteins over the lifetime, and hyperhomocysteinemia, ultimately result in tissue degeneration. The decline in renal functions, nutritional deficiencies, deregulation of methionine cycle and deficiencies of homocysteine remethylation and transsulfuration cofactors cause elevation of homocysteine with advancing age. Abnormal accumulation of homocysteine is a risk factor of cardiovascular, neurodegenerative and chronic kidney disease. Moreover, approximately 50% of people, aged 65 years and older develop hypertension and are at a high risk of developing cardiovascular insufficiency and incurable neurodegenerative disorders. Increasing evidence suggests inverse relation between cognitive impairment, cerebrovascular and cardiovascular events and renal function. Oxidative stress, inactivation of nitric oxide synthase pathway and mitochondria dysfunction associated with impaired homocysteine metabolism lead to aging tissue degeneration. In this review, we examine impact of high homocysteine levels on changes observed with aging that contribute to development and progression of age associated diseases.

Plasma Homocysteine Level and the Angiographic Extent of Coronary Artery Disease

Recent epidemiologic studies have shown that moderately elevated plasma homocysteine concentrations are associated with an increased risk for the development of atherosclerotic cardiovascular diseases. But, it is not known whether moderate hyperhomocysteinemia is associated with the angiographic extent of atherosclerotic cardiovascular disease in patients with coronary artery disease (CAD). A possible relationship was investigated between admission plasma homocysteine level and the angiographic extent of coronary artery disease in patients with CAD. In this study, 156 consecutive patients presenting with coronary artery disease (group 1) and control group (group 2) of 35 age-matched persons with normal coronary angiography were enrolled. Blood samples for homocysteine were obtained on admission. Plasma homocysteine concentration was measured with high-performance liquid chromatography with fluorescence detection. Radiographs from coronary angiography were viewed and scored using Sullivan’s method to assess the atherosclerotic involvement of coronary artery disease. There were significant elevations in homocysteine level in group 1 compared to group 2 (15.59 ±5.7 µmol/L, 9.24 ±1.50 µmol/L; respectively, p<0.001). All scores (demonstrated angiographic extension of CAD) correlated significantly with plasma homocysteine levels; however, the Sullivan’s extent score correlated more closely ( r =0.68, p<0.001) than both the stenosis score ( r =0.44, p<0.01) and vessel score ( r =0.35, p<0.05). Elevated homocysteine levels in patients with coronary artery disease correlated with the angiographic extent of atherosclerotic disease.

Dietary supplement S-adenosyl-L-methionine (AdoMet) effects on plasma homocysteine levels in healthy human subjects: a double-blind, placebo-controlled, randomized clinical trial

OBJECTIVES

To determine if exogenous S-adenosyl-l-methionine (AdoMet), a commonly used nutritional supplement, increases the level of plasma homocysteine (Hcy), a potential cardiovascular risk factor, in healthy human subjects.

DESIGN

Double-blind, placebo-controlled, randomized clinical trial.

SETTING

Mayo Clinic, Rochester, Minnesota.

SUBJECTS

Fifty-two (52) healthy human volunteers.

INTERVENTION

Subjects received placebo or AdoMet (800 mg per day) for 4 weeks. Hcy levels were measured before and after administration of AdoMet or placebo.

OUTCOME MEASURES

The primary outcome measure was change in Hcy level. Secondary outcome measures included an interim Hcy determination (at 2 weeks) and changes in levels of high-sensitivity C-reactive protein (hsCRP), lipids, and alanine aminotransferase.

RESULTS

There was no statistically significant change in Hcy between groups. Similarly, no statistically significant differences in change in Hcy or hsCRP levels were observed at 2 or 4 weeks. There was a small but statistically significant increase (p < 0.04) in alanine aminotransferase at week 2 and a statistically significant decrease (p < 0.04) in total cholesterol in the AdoMet group compared with the placebo group.

CONCLUSIONS

AdoMet at a daily dose of 800 mg for 4 weeks does not appear to significantly affect Hcy levels in the blood.

Mechanisms and potential therapeutic targets for folic acid in cardiovascular disease

Folic acid (FA) is a member of the B-vitamin family with cardiovascular roles in homocysteine regulation and endothelial nitric oxide synthase (eNOS) activity. Its interaction with eNOS is thought to be due to the enhancement of tetrahydrobiopterin bioavailability, helping maintain eNOS in its coupled state to favor the generation of nitric oxide rather than oxygen free radicals. FA also plays a role in the prevention of several cardiac and noncardiac malformations, has potent direct antioxidant and antithrombotic effects, and can interfere with the production of the endothelial-derived hyperpolarizing factor. These multiple mechanisms of action have led to studies regarding the therapeutic potential of FA in cardiovascular disease. To date, studies have demonstrated that FA ameliorates endothelial dysfunction and nitrate tolerance and can improve pathological features of atherosclerosis. These effects appear to be homocysteine independent but rather related to their role in eNOS function. Given the growing evidence that nitric oxide synthase uncoupling plays a major role in many cardiovascular disorders, the potential of exogenous FA as an inexpensive and safe oral therapy is intriguing and is stimulating ongoing investigations.

Homocysteine and glutathione peroxidase-1

Mildly elevated homocysteine levels (Hcy) increase the risk for atherothrombotic vascular disease in the coronary, cerebrovascular, and peripheral arterial circulations. The molecular mechanisms responsible for decreased bioavailability of endothelium-derived nitric oxide (NO) by Hcy involve an increase of vascular oxidant stress and inhibition of important antioxidant capacity. Glutathione peroxidase-1 (GPx-1), a selenocysteine-containing antioxidant enzyme, may be a key target of Hcy's deleterious actions, and several experimental and clinical studies have demonstrated a complex relationship between plasma total homocysteine (tHcy), GPx-1, and endothelial dysfunction. Hcy may promote endothelial dysfunction, in part by decreasing GPx-1 expression; however, there is evidence to suggest that overexpression of GPx-1 can compensate for these effects. This review summarizes the current knowledge of the metabolism of Hcy, the effects of hyperhomocysteinemia observed in in vitro and in vivo models that lead to endothelial dysfunction and the possible mechanisms for these actions, and the role of GPx-1 in the pathogenesis of Hcy-induced cardiovascular disease (CVD).

Homocysteine, Folate and Vitamin B12 in Patients with Coronary Heart Disease

BACKGROUND/AIMS

Homocysteine and possibly also folate and vitamin B(12) are involved in the pathogenesis of cardiovascular disease. We investigated the prevalence of hyperhomocysteinemia in patients with coronary heart disease (CHD), as well as folate and vitamin B(12), the main nutritional factors determining the level of homocysteine.

METHODS

Patients with angiographically documented CHD were prospectively investigated (n = 315, 70% male, mean age 61 [range 36-81] years). Fasting total serum homocysteine was determined by high-performance liquid chromatography and fluorescence detection. Folic acid and vitamin B12 were measured with AxSYMR Systems.

RESULTS

Median homocysteine concentrations for homocysteine, folate and vitamin B12 were 12.8 micromol/l, 6.8 ng/ml and 345 pg/ml, respectively. Homocysteine levels >10 micromol/l were found in 82% of men and 73% of women. In 19% of the patients serum folate was <3 ng/ml and 22% of the patients had serum vitamin B12 values <250 pg/ml. In a multivariate linear regression model, folate and vitamin B(12) showed significant negative correlations to homocysteine, explaining 5 and 3% of its variability. Age and creatinine were the most important determinants for serum homocysteine, contributing 12 and 7%, respectively.

DISCUSSION

The main determinants of total homocysteine in patients with CHD are higher age and increased creatinine. The association of lower levels of folate and vitamin B12 with higher levels of homocysteine may indicate poor dietary habits in these patients.

Hyperhomocysteinemia predicts total and cardiovascular mortality in high-risk women

OBJECTIVE

The impact of homocysteine on cardiovascular disease can be more detrimental in women than in men, but it is unknown whether this applies to high-risk women. We therefore investigated the association of hyperhomocysteinemia with coronary artery disease (CAD) and cardiovascular mortality in high-risk women referred for CAD, both in the total population and in the hypertensive and normotensive cohorts.

DESIGN

A prospective study cohort.

SETTING

A tertiary centre.

PATIENTS

INCLUSION CRITERIA

262 consecutive Caucasian postmenopausal women referred for coronary angiography.

EXCLUSION CRITERIA

acute myocardial infarction and vitamin supplementation.

MAIN OUTCOME MEASURE(S)

We assessed total plasma homocysteine (tHcy), folate levels, and the MTHFR677C-->T polymorphism. CAD was defined as a modified Duke Index score greater than 0; hyperhomocysteinemia as tHcy levels of 15 micromol/l or greater. The primary study outcome was cardiovascular mortality at follow-up.

RESULTS

Mild/moderate and severe hyperhomocysteinemia was found in 15.1 and 1.6% of women, respectively, without differences between CAD and non-CAD women. By the ATPIII criteria, 92.2% of the women were in the highest risk class and 55% had CAD; however, no association of tHcy with the CAD score was found. After a median follow-up of 3.6 years, 23 women (9.1%) had died, 15 (6%) of cardiovascular causes. Women with high tHcy levels showed the worst all-cause and cardiovascular death-free survival at Kaplan-Meier and Cox regression analysis. Moreover, in the hypertensive cohort only women with hyperhomocysteinemia showed increased cardiovascular mortality.

CONCLUSION

Hyperhomocysteinemia is common in high-risk women and adversely affects their prognosis, although it is unrelated to the CAD atherosclerotic burden.

Responsiveness of homocysteine concentrations to food and supplemental folate intakes in smokers and never‐smokers enrolled in a diet intervention trial

We investigated circulating homocysteine concentrations in relation to smoking, folate intake (from food and supplements), serum folate concentrations, and other dietary variables. The present study is part of a parent trial assessing the effects of increasing vegetable, fruit, and fiber intakes and reducing the percentage of energy obtained from fat on breast cancer recurrence in 3,088 women previously diagnosed with breast cancer. Of the 121 smokers enrolled in the parent trial, 85 were available at baseline for the present study and were randomly matched to 85 never-smokers on baseline folate intake, age, and intervention status. Follow-up data were available on 53 smokers (22 intervention and 31 comparison) and 56 never-smokers (24 intervention and 32 comparison). No significant differences in circulating homocysteine and folate concentrations were observed between smokers and never-smokers at baseline. For smokers, significant decreases in circulating homocysteine and significant increases in folate concentrations (p < .05) from baseline to 12 months were observed in the comparison group. For never-smokers, significant decreases in circulating homocysteine and significant increases in folate concentrations were observed in the intervention and comparison groups (p < .05). In the multivariate analysis, changes in serum folate concentration and supplemental folic acid were significantly associated with change in plasma homocysteine concentrations (p < .05). These findings show that increasing supplemental folic acid can reduce homocysteine concentrations, which may have implications for lowering cardiovascular disease risk for smokers and never-smokers.

Elevated plasma homocysteine levels in patients with isolated coronary artery ectasia

OBJECTIVE

Coronary artery ectasia is a variant of coronary atherosclerosis. Hyperhomocysteinemia has emerged as a major, independent risk factor for cardiovascular diseases. The purposes of this study were to determine plasma hyperhomocysteine levels in patients with coronary artery ectasia, and to compare patients with coronary artery ectasia, coronary artery disease, and controls with normal coronary angiogram.

METHOD

The study population included 37 patients with coronary artery ectasia and 36 patients with coronary artery disease. The control group consisted of 32 patients with angiographically proven normal coronary arteries. Plasma hyperhomocysteine levels were measured in all study patients with an enzyme-linked immunosorbent assay.

RESULTS

Plasma homocysteine levels were significantly higher in patients with both coronary artery ectasia and coronary artery disease than in the controls (14.8+/-1.1 and 15.9+/-0.8 vs. 2.5+/-0.6 micromol/l; P<0.001 and P<0.001, respectively). No significant differences in plasma homocysteine levels were found among CAE and CAD groups (P>0.05).

CONCLUSIONS

We have demonstrated that patients with coronary artery ectasia and coronary artery disease have increased plasma hyperhomocysteine levels compared with the controls. These findings suggest that hyperhomocysteinemia may play an important role in the pathogenesis of coronary artery ectasia as in coronary artery disease.

Homocysteine concentrations and vascular complications in patients with type 2 diabetes

OBJECTIVE

Hyperhomocysteinemia is a well known risk factor for the diseases of the cardiovascular system, which seem to be the main cause of increased mortality in patients with type 2 diabetes. The aim of the study was to evaluate the levels of homocysteine in patients with type 2 diabetes in respect to the regimen of diabetes treatment as well as the presence of diabetic complications.

METHODS

The investigation was carried out in the group of 64 patients with type 2 diabetes and in 18 healthy subjects from the control group. Clinical examination and measurements of homocysteine, folic acid, vitamin B12, glycosylated hemoglobin concentration and evaluation of parameters of the lipid metabolism, microalbuminuria and creatinine were done in both groups.

RESULTS

Homocysteine concentration was significantly higher in the group of patients with diabetes in comparison to the control group (p = 0.0007). Diabetic patients had significantly lower concentrations of folic acid (p = 0.028) and HDL cholesterol (p = 0.025) together with higher levels of systolic blood pressure (p = 0.007). In the group of patients with diabetes no differences in homocysteine levels were found in respect to diabetes treatment. Diabetic patients with coronary artery disease had significantly higher homocysteine concentration in comparison to the group with diabetes without history of coronary artery disease (p = 0.0097). Homocysteine levels correlated significantly with incidence of ischaemic heart disease (r = 0.44, p = 0.001) and microalbuminuria (r = 0.26, p = 0.019). Negative correlation was noticed in HDL concentrations (r = -0.30, p = 0.013) and the levels of folic acid (r = -0.30, p = 0.008).

CONCLUSION

Our results suggest that hyperhomocysteinemia in diabetic patients may contribute to the development of chronic complications. The influence of diabetes treatment on Hcy levels requires further observations.

Association between Hyperhomocysteinemia and Ultrasonographic Atherosclerotic Indices of Carotid Arteries in Chronic Hemodialysis Patients

BACKGROUND

Atherosclerotic cardiovascular events are a major cause of morbidity and the main cause of mortality in hemodialysis patients. Hyperhomocysteinemia--which is a consistent finding in uremic patients--is considered an independent risk factor for cardiovascular disease (CVD). However, the relationship between plasma homocysteine (Hcy) concentrations and atherosclerotic CVD has not been extensively investigated.

PATIENTS AND METHODS

37 patients undergoing chronic hemodialysis and 30 healthy individuals (control group), sex- and age-matched, were included in this study. Both healthy controls and hemodialysis patients underwent echo-Doppler carotid artery examination. The right and left carotid arteries were assessed separately. Our observation included measurements of the ultrasound images of the intimal wall thickness, the lumen diameter and the atherosclerotic plaques. We determined plasma Hcy, vitamin B12 and folic acid levels and serum cholesterol, triglycerides, HDL, ApoA-I, ApoB-100, Lp(a), CRP, albumin and creatinine levels in blood samples from both studied groups. We also determined the urea reduction ratio in the patient groups. The epidemiological as well as the biochemical data were correlated with the findings of the carotid artery examination.

RESULTS

Plasma Hcy levels were significantly increased in hemodialysis patients compared to controls (33 +/- 12.3 vs. 12.27 +/- 7.47 micromol/l, p < 0.001). Intimal wall thickness, lumen diameter and number of atherosclerotic plaques of both carotid arteries were significantly higher (p < 0.01 or p < 0.001) in patients compared to controls. There was a significant positive correlation between plasma Hcy levels and the number of the atherosclerotic plaques (r = 0.41, p < 0.01 in the right and r = 0.49, p < 0.001 in the left carotid artery). Lumen diameter was significantly (p < 0.01) associated with age, MAP and CRP levels. Significant correlations (p = 0.05-0.01) were also found between the number of the plaques and age as well as the duration of hemodialysis, while folic acid levels were inversely correlated with the number of the plaques.

CONCLUSIONS

Both hyperhomocysteinemia and atherosclerotic indices of the carotid arteries are more prevalent in hemodialysis patients compared to healthy controls. Elevated plasma Hcy levels were associated with the carotid artery atherosclerotic indices in chronic hemodialysis patients.

Plasma homocysteine predicts progression of atherosclerosis

MINI ABSTRACT: Three emerging risk factors potentially useful in predicting future cardiac events are electron-beam computed tomography (EBT), homocysteine(HCY), and C-reactive Protein (CRP). We evaluated a cohort of 133 serial asymptomatic patients, who underwent two consecutive EBT scans (8-84 months apart) and a comprehensive cardiac risk factor assessment, including measurements for lipids, ultrasensitive CRP and homocysteine. Individuals with elevated HCY (> or =12 micromol/L) demonstrated a mean increase in CC progression of 35% per year, while those with HCY <12 micromol/L (median) progressed at 17% per year (p = 0.0008). Patients with a level equal to or lower than the median value of CRP (0.8 mg/L) had a median yearly progression of 22%, compared to 21% for those with CRP value = 0.9-11 mg/L (p = ns). Presence of elevated HCY (>12 micromol/L) strongly and independently predicts progression of coronary plaque burden.

BACKGROUND

Despite the availability of effective preventive therapies, coronary artery disease (CAD) remains the leading cause of morbidity and mortality. Use of traditional cardiovascular risk factors is imprecise and predicts less than one half of future cardiovascular events. Three 'emerging risk factors', as potential means of identifying subclinical atherosclerosis and predicting future cardiovascular events, are electron-beam computed tomography, homocysteine, and C-reactive protein. Given the evidence that HCY and CRP are involved in atherogenesis, we hypothesized that significant progression of EBT calcium score (a measure of atherosclerotic plaque burden) is associated with higher levels of these markers.

METHODS

We evaluated 133 asymptomatic patients (100 men, 33 women; mean age was 61 +/- 9 years) who underwent previous EBT calcium score testing at Harbor-UCLA 8-80 months prior to enrollment (mean follow-up 20 months). Exclusion criteria included those with known or symptomatic CAD and chronic renal disease. During enrollment, we measured risk factors, serum HCY, serum lipids, ultrasensitive-CRP, and repeat EBT calcium scan. Statistical analysis was performed using probable Chi square method, and Student's t-test.

RESULTS

Individuals with elevated HCY (> or =12 micromol/L) demonstrated a mean increase in CC progression of 35% per year, while those with HCY <12 micromol/L (median) progressed at 17% per year (p = 0.0008). Patients with a level equal to or lower than the median value of CRP (0.8 mg/L) had a median yearly progression of 22%, compared to 21% for those with CRP value = 0.9-11 mg/L (p = ns). Neither cholesterol values, body mass index, gender, age nor presence of individual risk factors predicted progression of coronary calcium.

CONCLUSION

Presence of elevated HCY (>12 micromol/L) strongly and independently predicts progression of coronary plaque burden.

Homocysteine and B vitamins

Homocysteine (tHcy) is an intermediate sulfur-containing amino acid which acts as a methyl group donor for methionine metabolism. Increased serum concentrations (=hyperhomocysteinemia, >10 micromol/l) have been associated with an increased cardiovascular risk. Homocystinuria, an infrequent genetic disease usually due to lack of cystathione beta-synthase, has been found with severely elevated serum homocysteine values (>150 micromol/l). Functional gene polymorphisms of key enzymes (e.g., N5,N10-methylene-tetrahydrofolate reductase) and dietary B-vitamin deficiencies in the elderly are, however, frequent in the 'Western' population. Hyperhomocysteinemia has been associated with other vascular effects such as atherothrombosis and endothelial dysfunction due to its auto-oxidative potential, thereby increasing the production of reactive oxygen species. Other effects may involve neurodegenerative diseases such as Alzheimer or dementia praecox of the elderly. Therapeutic interventions lowering tHcy may therefore offer novel tools for the prevention and treatment of atherosclerosis. B-vitamin supplementation (folic acid=vitamin B9, vitamin B6 and vitamin B12) is an efficient and safe tHcy-lowering therapy, decreases tHcy by 30%-50% and has been shown to lower cardiovascular morbidity and mortality. Furthermore, folic acid supplementation has been shown to reduce or even almost eliminate neurotubular birth defects (spina bifida) and to markedly decrease the rate of megaloblastic anemia. Thus, fortification of flour with folic acid in the USA was advocated several years ago in order to prevent these entities.

Association of serum total homocysteine with the extent of ischemic heart disease in a Mediterranean cohort

High total homocysteine (tHcy) concentrations increase coronary disease risk. Therefore, the authors examined the relation between tHcy concentrations and the number of stenotic arteries in patients with ischemic heart disease (IHD). They enrolled 155 patients with IHD (135 men) who had undergone selective coronary angiography during the previous 2 years. These patients were divided into 4 groups according to the number of vessels (0, 1, 2, and 3) with > or = 70% stenosis. They also reviewed the major coronary risk factors for each patient (age, gender, hypertension, diabetes mellitus, dyslipidemia, cigarette smoking, obesity), and measured serum concentrations of tHcy, folate, vitamin B12 and lipids. There was a significant positive correlation (rs = 0.19; p = 0.017; n = 155) between tHcy serum concentration and the extent of coronary atherosclerosis, expressed by the number of coronary arteries with significant stenosis. Moreover, the number of affected vessels displayed a significant positive correlation with the presence of diabetes mellitus (rs = 0.30; p < 0.0001; n = 155) and serum concentrations of lipoprotein (a) (rs = 0.25; p < 0.05; n = 67) and a negative correlation with apolipoprotein A-I serum concentration (rs = -0.27; p < 0.01; n = 67). In this study, the serum concentrations of tHcy correlated with the extent of coronary atherosclerosis, independently of other classical risk factors, with the exception of diabetes mellitus.

Association between plasma homocysteine levels and coronary artery disease: a population-based study in northern Greece

OBJECTIVE

Elevated plasma total homocysteine (tHcy) levels constitute a risk factor for coronary artery disease (CAD). We prospectively examined the association of fasting tHcy levels in patients in Northern Greece who had established CAD.

PATIENTS AND METHODS

Plasma fasting tHcy levels were measured in 42 patients with angiographically documented CAD and compared to 42 age-, sex-, BMI- and smoking habit-matched control subjects. We also determined the plasma vitamin B(12), folic acid and lipoprotein levels in all patients and controls. Conventional risk factors for CAD were also estimated.

RESULTS

In a univariate analysis, tHcy (micromol/l) levels were higher in patients compared to controls almost reaching statistical significance (13 (7-41) vs 11.3 (4-39); p= 0.07). Multivariate analysis of conventional risk factors showed that tHcy levels were not an independent risk factor for CAD. However, tHcy levels were significantly higher in patients with a previous history of myocardial infarction compared to patients without such a history and to controls (15 (8.8-29) vs 11.7 (7-41); p = 0.007 and 15 (8.8-29) vs 11.3 (4-39); p = 0.002, respectively). Hyperhomocysteinaemia (> 15 micromol/l) was detected in 35.7% of patients and 11.9% of controls (p < 0.05).

CONCLUSIONS

In Northern Greece, plasma tHcy levels may not be an independent risk factor for CAD in patients with angiographically documented CAD. However, patients with CAD have a trend towards higher tHcy levels. Additionally, plasma tHcy levels may be associated with the development of myocardial infarction.

Genetic polymorphisms in folate and homocysteine metabolism as risk factors for DNA damage

Epidemiological studies indicated a role for polymorphisms in genes of folate and homocysteine (Hcy) metabolism in the etiology of neurodegenerative disease, congenital defects and coronary artery disease (CAD). This study investigated the effect of several polymorphisms [C677 T, A1298C of methylenetetrahydrofolate reductase (MTHFR) and A66G of methionine synthase reductase (MTRR) genes] on Hcy levels and DNA damage in 68 patients who underwent coronary angiography. Plasma Hcy concentrations were higher in patients with multivessel disease with respect to monovessel disease and no-CAD patients (19.4+/-2.6 vs 11.6+/-1.2 and 13.7+/-1.4 micromol/l, respectively; P=0.03). 677TT patients had higher Hcy levels than those with 677CC or 677CT genotypes (26.2+/-4.3 vs 13.1+/-1.4 and 13.0+/-1.4 micromol/l, respectively; P=0.0006). No significant associations were found between A1298C and A66G polymorphisms and plasma Hcy levels. Among patients with 677CC genotype, 66GG individuals tended to have higher levels of Hcy than 66AA homozygotes (14.5+/-1.9 vs 8.9+/-0.7 micromol/l, P=0.06). Multivessel disease patients showed an increased frequency of DNA damage, measured by the micronucleus (MN) frequency, as compared to monovessel disease and no-CAD subjects (12.5+/-1.1 vs 8.5+/-0.8 and 8.2+/-0.9, respectively; P=0.006). The MN were positively correlated with Hcy levels (r=0.33, P=0.006) and were significantly higher in subjects with the 677TT genotype compared with the 677CC or 677CT genotypes (14.4+/-2.0 vs 8.8+/-1.2 and 9.5+/-0.7, respectively; P=0.006). A1298C and A66G polymorphisms had no effect on MN frequency. However, among 677TT patients, 66GG subjects tended to have higher levels of MN than those 66AG and 66AA (18.2+/-3.6 vs 13.8+/-4.0 and 10.3+/-1.7, respectively; P=NS). Our results indicate that genetic instability may be associated with increased risk for multiple Hcy-related diseases.

Plasma homocysteine levels and late outcome after coronary angioplasty

OBJECTIVES

The aim of this study was to evaluate a possible relationship between homocysteine levels on admission and late outcome after successful percutaneous coronary intervention (PCI).

BACKGROUND

Increasing evidence suggests that mild to moderate elevation of total plasma homocysteine is a graded and potentially modifiable risk factor for cardiovascular disease and death that appears to be largely independent of other traditional risk factors.

METHODS

A total of 549 patients were included after successful PCI of at least one coronary stenosis (> or =50%). End points were cardiac death, nonfatal myocardial infarction (MI), target lesion revascularization (TLR), and a composite of major adverse cardiac events (MACE). The relationship between homocysteine levels and study endpoints was assessed.

RESULTS

After a median (+/- SD) follow-up of 58 +/- 20 weeks, 6 patients died of cardiac death, 14 were diagnosed with a new MI, and 71 underwent repeat TLR. A graded relationship between homocysteine levels (quartiles) and freedom from MACE was found (p = 0.01). Homocysteine levels (+/- SD) were associated with cardiac death (14.9 +/- 1.7 micromol/l vs. 9.6 +/- 4.3 micromol/l, p < 0.005), TLR (10.7 +/- 4.4 micromol/l vs. 9.5 +/- 4.3 micromol/l, p < 0.05), and overall MACE (11.0 +/- 4.4 micromol/l vs. 9.4 +/- 4.3 micromol/l, p < 0.005). These findings remained unchanged after adjustment for potential confounders.

CONCLUSIONS

Plasma homocysteine is an independent predictor of mortality, nonfatal MI, TLR, and overall adverse late outcome after successful coronary angioplasty.

Endothelial dysfunction and atherothrombosis in mild hyperhomocysteinemia

Mildly elevated plasma homocysteine levels are an independent risk factor for atherothrombotic vascular disease in the coronary, cerebrovascular, and peripheral arterial circulation. Endothelial dysfunction as manifested by impaired endothelium-dependent regulation of vascular tone and blood flow, by increased recruitment and adhesion of circulating inflammatory cells to the endothelium, and by a loss of endothelial cell antithrombotic function contributes to the vascular disorders linked to hyperhomocysteinemia. Increased vascular oxidant stress through imbalanced thiol redox status and inhibition of important antioxidant enzymes by homocysteine results in decreased bioavailability of the endothelium-derived signaling molecule nitric oxide via oxidative inactivation. This plays a central role in the molecular mechanisms underlying the effects of homocysteine on endothelial function. Supplementation of folic acid and vitamin B12 has been demonstrated to be efficient in lowering mildly elevated plasma homocysteine levels and in reversing homocysteine-induced impairment of endothelium-dependent vasoreactivity. Results from ongoing intervention trials will determine whether homocysteine-lowering therapies contribute to the prevention and reduction of atherothrombotic vascular disease and may thereby provide support for the causal relationship between hyperhomocysteinemia and atherothrombosis.

Pharmacology of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins), including rosuvastatin and pitavastatin

Coronary heart disease (CHD) is the leading cause of morbidity and mortality in the Western world, with hypercholesterolemia as the major risk factor. The 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors represent the most efficient drugsfor the treatment of hypercholesterolemia. They lower plasma cholesterol due to the inhibition of endogenous cholesterol synthesis in the liverand subsequent increased expression of low-density lipoprotein (LDL) receptors, resulting in an up-regulated catabolic rate for plasma LDL. The beneficial effect of statins on the incidence of CHD was clearly demonstrated in several large-scale clinical trials. Currently, five statins (atorvastatin, fluvastatin, lovastatin, pravastatin, and simvastatin) are available, and two novel compounds (pitavastatin, rosuvastatin) are undergoing clinical investigation. To point out potential mechanisms leading to increased toxicity and to compare the novel statins with the established ones, this article summarizes their pharmacological data since the prevalence of adverse events can be explained at least in part by their pharmacokinetic differences.

Decreased rate of coronary restenosis after lowering of plasma homocysteine levels

BACKGROUND

We have previously demonstrated an association between elevated total plasma homocysteine levels and restenosis after percutaneous coronary angioplasty. We designed this study to evaluate the effect of lowering plasma homocysteine levels on restenosis after coronary angioplasty.

METHODS

A combination of folic acid (1 mg), vitamin B12 (400 microg), and pyridoxine (10 mg)--referred to as folate treatment--or placebo was administered to 205 patients (mean [+/-SD] age, 61+/-11 years) for six months after successful coronary angioplasty in a prospective, double-blind, randomized trial. The primary end point was restenosis within six months as assessed by quantitative coronary angiography. The secondary end point was a composite of major adverse cardiac events.

RESULTS

Base-tine characteristics and initial angiographic results after coronary angioplasty were similar in the two study groups. Folate treatment significantly lowered plasma homocysteine levels from 11.1+/-4.3 to 7.2+/-2.4 micromol per liter (P<0.001). At follow-up, the minimal luminal diameter was significantly larger in the group assigned to folate treatment (1.72+/-0.76 vs. 1.45+/-0.88 mm, P=0.02), and the degree of stenosis was less severe (39.9+/-20.3 vs. 48.2+/-28.3 percent, P=0.01). The rate of restenosis was significantly lower in patients assigned to folate treatment (19.6 vs. 37.6 percent, P=0.01), as was the need for revascularization of the target lesion (10.8 vs. 22.3 percent, P=0.047).

CONCLUSIONS

Treatment with a combination of folic acid, vitamin B12, and pyridoxine significantly reduces homocysteine levels and decreases the rate of restenosis and the need for revascularization of the target lesion after coronary angioplasty. This inexpensive treatment, which has minimal side effects, should be considered as adjunctive therapy for patients undergoing coronary angioplasty.