Homocysteine and cardiovascular disease: current evidence and future prospects

Biomarkers of cardiovascular disease as risk factors for age-related macular degeneration

PURPOSE

To measure and contrast 2 biomarkers of cardiovascular disease, C-reactive protein (CRP) and plasma homocysteine, in individuals with age-related macular degeneration (AMD) and control individuals without AMD.

DESIGN

Case-control study.

PARTICIPANTS

Seventy-nine affected individuals and 77 unaffected individuals from the AMD Genetic Study Group returned to obtain CRP and homocysteine levels.

METHODS

Both affected and unaffected individuals underwent testing for CRP and homocysteine. A detailed cardiovascular history was taken.

MAIN OUTCOME MEASURES

Mean CRP and homocysteine levels in affected and unaffected individuals.

RESULTS

Mean CRP levels for affected and unaffected individuals were 3.42 and 2.30 mg/l, respectively (P = 0.03). Mean homocysteine levels for affected and unaffected individuals were 11.72 and 8.88 micromol/l, respectively (P<0.0001). In logistic regression models, older age, higher CRP, and higher homocysteine were risk factors for AMD. There were no significant differences between cases and controls in terms of gender, diabetes, hypertension, use of statin drugs, and smoking. The control group was significantly younger and had a lower rate of vitamin usage than the affected group.

CONCLUSIONS

Elevated CRP and homocysteine levels are associated with AMD and implicate the role of chronic inflammation and atherosclerosis.

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.

Plasma homocysteine levels and the left ventricular systolic function in coronary artery disease patients

BACKGROUND

Numerous studies have shown a relationship between hyperhomocysteinemia, atherothrombosis and cardiovascular mortality. However, an association between hyperhomocysteinemia and the extent of coronary artery disease (CAD) remains controversial whereas its relationship with left ventricular systolic function has not been established.

METHODS

One hundred and fifty-seven patients with angiographically defined CAD were included. The relationships between hyperhomocysteinemia, severity of CAD and left ventricular systolic function were studied. Left ventricular systolic function was determined primarily by ventriculography. The severity of CAD was determined through coronary angiography using the Gensini score and the number of vessels with > or = 50% stenosis.

RESULTS

The mean fasting plasma homocysteine level was 13.4 mumol/l+/-0.5 SE. Elevated levels of homocysteine correlated significantly with increased severity of CAD both by the Gensini scores (r-value = 0.344, P < 0.0005) and the total number of diseased vessels (r-value = 0.387, P < 0.0005). The patients with hyperhomocysteinemia were found to have significantly reduced left ventricular ejection fraction (r-value = -0.382, P < 0.0005). A multivariate regression analysis revealed homocysteine level to be an independent predictor of left ventricular systolic function. In addition, adjusted analysis revealed hyperhomocysteinemia to be associated with global left ventricular dysfunction.

CONCLUSION

In patients with CAD, homocysteine levels correlate independently with left ventricular systolic function. The mechanism of this association between homocysteine and left ventricular systolic function is unknown but may be due to a direct effect of homocysteine on myocardial function separate from its effects on coronary atherosclerosis.

Homocysteinemia as well as methylenetetrahydrofolate reductase polymorphism are associated with affective psychoses

In the recent years, elevated homocysteine plasma levels have been reported to represent a risk factor not only for atherosclerosis, but also to be associated with dementia, depression and-in a gender-specific manner-schizophrenia. Here, we explored a possible association between homocysteinemia and psychiatric disorders. Fasting homocysteine, vitamin B12 and folate were determined in an ethnically homogeneous female population with different psychiatric disorders. Homocysteine was not elevated in females suffering from schizophrenia (mean, 11.6+/-5.8 micromol/l). As shown previously, increased homocysteine concentrations were associated not only with dementia of different aetiology (mean, 17.2+/-6.7 micromol/l; chi2=23.39, p<0.001, compared to the schizophrenia group), but also with depressive disorders (mean, 12.9+/-3.8 micromol/l; chi2=6.88, p=0.009). B12 and folate levels did not differ between different diagnostic groups. To further explore the connection between homocysteinemia and affective psychoses, a case-control study examining the C677T and the A1298C variants of methylenetetrahydrofolate reductase was conducted. The latter polymorphism not only was associated with affective psychoses in general, but also when divided in unipolar depression and bipolar affective disorder. In conclusion, we suggest that in females homocysteinemia is an unspecific risk factor for organic brain disorders like dementia, and possibly depression, but not for schizophrenia.

A proinflammatory state is associated with hyperhomocysteinemia in the elderly

BACKGROUND

The mechanism by which high circulating homocysteine concentrations are a risk factor for atherothrombosis is incompletely understood. A proinflammatory state is related to atherosclerosis, and recent studies suggest that acute phase reactants correlate with circulating concentrations of homocysteine.

OBJECTIVE

We determined whether high concentrations of inflammatory markers are associated with hyperhomocysteinemia independently of dietary vitamin intakes, vitamin concentrations, and cardiovascular disease risk factors in a large, representative sample of the general population.

DESIGN

Five hundred eighty-six men and 734 women were randomly selected from the inhabitants of 2 small towns near Florence, Italy.

RESULTS

After adjustment for multiple potential confounders, interleukin 1 receptor antagonist (IL-1ra) and interleukin 6 (IL-6) concentrations were significantly (P < 0.001) associated with plasma homocysteine concentrations in older (>65 y) populations. Compared with participants in the lowest IL-6 tertile, those in the highest tertile had a higher risk of having homocysteine concentrations that were high (>30 micromol/L; odds ratio: 2.6; 95% CI: 1.1, 5.6; P = 0.024) or in the intermediate range 15-30 micromol/L (odds ratio: 1.6; 95% CI: 1.2, 2.2; P = 0.0014). Sedentary state, intakes of vitamin B-6 and folic acid, and serum folate, vitamin B-12, vitamin B-6, and alpha-tocopherol concentrations were significant independent correlates of homocysteine.

CONCLUSIONS

High circulating concentrations of IL-1ra and IL-6 are independent correlates of hyperhomocysteinemia and may explain, at least in part, the association between homocysteine and atherosclerosis.

Endothelial Nitric Oxide Synthase −786T>C, but Not 894G>T and 4a4b, Polymorphism Influences Plasma Homocysteine Concentrations in Persons with Normal Vitamin Status

Background: Nitric oxide (NO) plays a relevant role in various events during atherogenesis. In vitro data suggest that NO may modulate homocysteine (Hcy) concentrations. The aim of this study was to investigate the role of endothelial nitric oxide synthase (eNOS) −786T&gt;C, 894G&gt;T, and 4a4b polymorphisms in influencing Hcy concentrations.

Methods: Blood samples were obtained from 1287 unrelated persons. Plasma Hcy was measured by fluorescence polarization immunoassay, folate and vitamin B12 by RIA, vitamin B6 by HPLC, and eNOS and methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms by PCR with restriction fragment length polymorphism analysis.

Results: MTHFR 677C&gt;T polymorphism significantly influenced Hcy concentrations after adjustment for all confounding variables (P &lt;0.0001 for trend). Univariate analysis showed that the eNOS −786T&gt;C polymorphism, but not 894G&gt;T and 4a4b, was significantly associated with the risk of having Hcy in the third tertile [&gt;13.4 μmol/L; odds ratio (OR) = 1.2; 95% confidence interval (CI), 1.02–1.5; P = 0.03]. After adjustment for all variables known to influence Hcy, the −786T&gt;C polymorphism still influenced Hcy concentrations (OR = 1.9; 95% CI, 1.1–3.2; P = 0.01). By analyzing the influence of eNOS polymorphisms on plasma Hcy concentrations according to vitamin concentrations (folate, vitamin B6, and vitamin B12), age, and smoking habits, we found a significant association between the eNOS −786T&gt;C polymorphism and Hcy in nonsmokers, in persons with normal vitamin status, and in persons &lt;60 years.

Conclusion: The eNOS −786T&gt;C polymorphism, but not 894G&gt;T and 4a4b, influences plasma Hcy concentrations mildly but significantly and independently.

Age, menopausal status and homocysteine levels in women around menopause

OBJECTIVE

To obtain data on the relation between age, menopause and homocysteine levels in women around menopause, we collected data for a sample of about 500 women attending a menopause clinic in Milan, Italy.

STUDY DESIGN

Eligible for the study were all women aged 45-75 years, never HRT users consecutively observed for the first time at the Menopause Center of the 1st Obstetric Gynecological Clinic of the University of Milan. Fasting blood samples for total homocysteine plasma levels were collected during the visit. Of the 490 study subjects, 107 were pre-menopausal and 383 post-menopausal.

RESULTS

In the total series, the mean homocysteine level was 8.3 micromol/L (S.D. 3.7, range 3.2-48.8). The values increased from 7.8 micromol/L in women aged <47 years to 9.0 micromol/L in those aged >59. Among pre-menopausal women the mean homocysteine level was 7.7 micromol/L compared to 8.3 micromol/L in post-menopausal women: this difference disappeared on the adjusted values. In post-menopausal women only, no clear relationship emerged between years since menopause and homocysteine levels.

CONCLUSION

In our population, age, and not menopausal status, was the main determinant of homocysteine levels in women around menopause.

Hiperhomocisteinemia na insuficiência renal crônica

A homocisteína é um aminoácido sulfurado proveniente do metabolismo da metionina, cujo acúmulo anormal no plasma é um fator de risco para doenças vasculares, tanto na população em geral como nos pacientes com insuficiência renal crônica. Nestes, a prevalência de indivíduos com hiperhomocisteinemia é bastante elevada, mesmo na fase não dialítica da doença, em que a função renal está diminuída, mas ainda não é necessário tratamento dialítico. O principal fator que parece estar implicado na elevação dos níveis de homocisteína nestes pacientes com insuficiência renal crônica é a perda da massa renal, já que esta exerce uma importante função no metabolismo desse aminoácido. O tratamento da hiperhomocisteinemia na população em geral consiste na suplementação com as vitaminas envolvidas no seu metabolismo (folato, B6 e B12). Porém, em pacientes com insuficiência renal crônica, este tratamento não é completamente eficaz, pois apesar de promover a redução dos níveis de homocisteína, não alcança a normalização dos mesmos na maioria dos pacientes. Este estudo compreende uma revisão da etiologia da hiperhomocisteinemia na insuficiência renal crônica, sua relação com as doenças vasculares, seus principais determinantes e as formas de tratamento.

Homocysteine as a risk factor for CVD mortality in men with other CVD risk factors: the Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study

OBJECTIVE

Based on case-control and prospective studies elevated blood total homocysteine (tHcy) has been suggested to be an independent risk factor for cardiovascular diseases (CVD). The purpose of the study was to explore the joint effect of increased serum tHcy concentration and other risk factors on the risk of CVD mortality in middle-aged men without a history of heart disease or stroke.

DESIGN

A prospective, population-based Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study.

SETTING

Eastern Finland. Subjects. A total of 802 men aged 46-64 years, examined in 1991-93.

MAIN OUTCOME MEASURES

CVD mortality event.

RESULTS

The mean serum tHcy concentration was 10.8 micromol L(-1) (SD 3.3). During the average follow-up time of 10.8 years 50 men experienced a CVD death. The hazard rate ratio for CVD mortality was 1.80 (95% confidence interval: 1.02-3.19) in men in the highest serum tHcy third versus lower thirds after adjustment for cardiovascular risk factors. Furthermore, elevated serum tHcy concentration appeared to increase the risk of CVD death in men who smoke or who have high circulating concentrations of serum total or LDL cholesterol, apo-B apolipoprotein or plasma fibrinogen.

CONCLUSION

We conclude that homocysteine may increase the risk of CVD mortality in middle-aged men from Eastern Finland, and it may especially increase the risk when present with other risk factors for CVD.

Intermittent rises in plasma homocysteine in patients with rheumatoid arthritis treated with higher dose methotrexate

OBJECTIVES

To investigate the effect of higher weekly maintenance dose methotrexate (MTX) (> or =25 mg/week) on plasma homocysteine concentrations in adults with RA.

METHODS

Patients with RA were treated with high doses of MTX with adjuvant folic acid. Plasma homocysteine was determined at baseline and 1, 2, 4, 8, 12, and 48 hours after subcutaneous MTX administration. Maximum homocysteine concentrations after MTX administration were compared with baseline concentrations.

RESULTS

Fifteen patients with RA (11 women) were included, with a median age of 61 years (range 31-72) and median disease duration 7 years (range 2-32). Median MTX dose was 30 mg (range 25-40). All patients received folic acid supplementation (5-30 mg/week). Median plasma homocysteine concentration at baseline was 10.1 mumol/l (range 6.6-12.7; normal 6-15). Homocysteine concentrations increased after MTX administration by a median of 2.5 mumol/l (range 0.7-5.1). Median maximum plasma homocysteine was significantly higher than at baseline. Peak homocysteine was reached after 12 hours. No relation between serum folate concentrations and plasma homocysteine concentrations was found.

CONCLUSIONS

In patients with RA higher MTX doses with adjuvant folic acid do not increase baseline concentrations of homocysteine. An intermittent significant rise in plasma homocysteine occurs in the 48 hours after MTX administration.

Trombosis arterial y polimorfismos genéticos: demasiados actores, escenario complejo

Arterial thrombosis results from complex gene-gene and gene-environment interactions. While Vichow's triad was traditionally referred to venous thrombosis, the same process has been applied to arterial thrombosis: abnormalities of hemorrheology, abnormal blood constituents and abnormal vessel wall/endothelial dysfunction. Research carried out in the past decade has identified several polymorphisms in genes related to coagulation and fibrinolytic factors, platelet receptors, endothelial dysfunction, homocysteine metabolism, endothelial nitric oxide synthase, abnormal blood flow and oxidative stress. Whereas the individual contribution of each polymorphism to the overall cardiovascular risk seems to be modest, multiple gene-gene and gene-environment interactions appear more relevant in the pathogenesis of arterial thrombosis.

Cobalamin: a critical vitamin in the elderly

Vitamin B(12) deficiency is a common problem in elderly subjects. If a serum cobalamin level of about 150 pmol/L (200 pg/mL) is considered normal, 10-15% of the elderly are deficient. Today, however, a threshold of 220-258 pmol/L (300-350 pg/mL) is recognized as desirable in the elderly, or else sensitive markers like the blood concentration of homocysteine or methylmalonic acid (MMA) are used. Then the prevalence of cobalamin deficiency rises to up to 43%. In the elderly, this high prevalence of poor cobalamin status is predominantly caused by atrophic gastritis type B. Atrophic gastritis results in declining gastric acid and pepsinogen secretion, and hence decreasing intestinal absorption of the cobalamin protein complexes from food. About 20-50% of the elderly are affected. Furthermore, the reduced acid secretion leads to an alkalinization of the small intestine, which may result in bacterial overgrowth and thus to a further decrease of the bioavailability of the vitamin. In addition, some drugs such as proton pump inhibitors or H2 receptor antagonists inhibit the intestinal absorption of vitamin B(12). An already moderately reduced vitamin B(12) level is associated with vascular disease and neurocognitive disorders such as depression and impaired cognitive performance. Furthermore, a poor vitamin B(12) status is assumed to be involved in the development and progression of dementia (e.g., Alzheimer's dementia). This is especially observable if the folic acid status is reduced as well. Due to the insecure supply, the cobalamin status of elderly persons (>/=60 years) should be regularly controlled and a general supplementation with vitamin B(12) (>50 microg/day) should be considered.

Methylenetetrahydrofolate reductase polymorphism (C677T), hyperhomocysteinemia, and risk of ischemic cardiovascular disease and venous thromboembolism: prospective and case-control studies from the Copenhagen City Heart Study

Hyperhomocysteinemia is associated with ischemic cardiovascular disease (ICD) and venous thromboembolism (VTE). We tested the hypothesis that methylenetetrahydrofolate reductase (MTHFR) C677T homozygosity with hyperhomocysteinemia is associated with ICD and VTE. First, 9238 randomly selected whites from the general population were followed for 23 years. Second, 2125 whites with ischemic heart disease and 836 whites with ischemic cerebrovascular disease were compared with 7568 controls from the general population. Plasma homocysteine was elevated 25% in homozygotes versus noncarriers (P &lt; .001) and 19% in ICD/VTE cases versus controls (P &lt; .001). In prospective studies adjusted hazard ratios for ICD and VTE for homozygotes versus noncarriers did not differ from 1.0. Furthermore, MTHFR C677T homozygosity was not associated with increased risk of ICD or VTE in subgroups after stratification for sex, age, cholesterol, high-density lipoprotein cholesterol, lipoprotein(a), fibrinogen, triglycerides, body mass index, smoking, diabetes mellitus, hypertension, and factor V Leiden genotype. Finally, in case-control studies odds ratios for ischemic heart disease and ischemic cerebrovascular disease in homozygotes versus noncarriers did not differ from 1.0. In conclusion, MTHFR C677T homozygosity with hyperhomocysteinemia is not associated with ICD or VTE; however, ICD/VTE is associated with hyperhomocysteinemia. Therefore, ICD and VTE may cause hyperhomocysteinemia, rather than vice versa.

Homocysteine effect on protein degradation rates

OBJECTIVES

To show the effect of homocysteine (Hcy) on the degradation rates of proteins.

DESIGN AND METHODS

Degradation rates of short-lived proteins in neutrophils were measured in in vivo human model of elevated plasma Hcy and lower vitamin status and in animal model of Hcy added in vitro to rat neutrophils.

RESULTS

In the human study, we found significant coefficients of correlation between plasma total homocysteine (tHcy) and the degradation rates of 21 protein fractions. In the animal model, Hcy significantly increased degradation rates of 57 protein fractions.

CONCLUSIONS

The increase in protein degradation rates, induced by Hcy, may provide a clue to our understanding of the mechanism of Hcy detrimental effects. Hcy may amplify the specific effect of cellular solutes on protein conformation, thereby monitor protein degradation rates to control enzyme activity. Consequently, the cell may lose its ability to maintain an efficient control of some crucial metabolic pathways, possibly leading to atherogenesis.

Homocysteine and cardiovascular disease

Research over the past decade has shown that elevated levels of homocysteine have a strong association with all forms of atherothrombotic disease and venous thromboembolism. This association is particularly strong for coronary disease and newer data indicate that screening for homocysteine levels may be warranted in those with unexplained thrombotic tendencies and in young patients who develop coronary events or disease without the usual predisposing factors such as hypertension, smoking, hypercholesterolemia, or diabetes. Although the link between hyperhomocysteinemia and cardiac disease has not been conclusively shown to be causal as yet, data are emerging that lowering homocysteine levels may be beneficial in patients at high risk. Such lowering can be done safely and inexpensively with increased intake of fruits and vegetables and in those patients who are particularly at high risk using supplementation with folic acid and the B vitamins. Preliminary studies have shown that lowering homocysteine levels in this manner may slow the progression of atherosclerosis in coronary and carotid vessels. No mortality data exist yet showing that reducing homocysteine reduces cardiac or total mortality, although it is likely that ongoing and planned trials that are underway will shed light on these important questions soon.

High dietary methionine plus cholesterol exacerbates atherosclerosis formation in the left main coronary artery of rabbits

Although mild hyperhomocysteinemia is a risk factor for cardiovascular events and mortality, there is no evidence to suggest that mild hyperhomocysteinemia stimulates coronary artery atherosclerosis formation.

OBJECTIVE

To compare the development of coronary artery atherosclerosis in rabbits following the induction of hyperhomocysteinemia and hypercholesterolemia through diet, and whether the combination of these risk factors exacerbated atherosclerosis formation.

METHODS

New Zealand White rabbits were fed for 12 weeks either a control diet, a 1% methionine diet (Meth), a 0.5% cholesterol diet (Chol) or the combination of the two diets (MethChol). Using volumetric stereological techniques, we quantitated the volume of intima, media and lumen of the left main coronary artery (LMCA).

RESULTS

Atherosclerosis was present in the Chol group, and increased in the MethChol group. There was no atherosclerosis in the control or Meth groups.

CONCLUSIONS

These results underscore the difference in the atherogenicity of hypercholesterolemia alone and mild hyperhomocysteinemia alone. Thus, we suggest that isolated mild hyperhomocysteinemia is not a risk factor for the initiation of coronary artery atherosclerosis formation over a short period of time, but may act in conjunction with other risk factors to further increase plaque formation.

Clinical application of genetic risk assessment strategies for coronary artery disease: genotypes, phenotypes, and family history

Individuals with genetic predisposition to atherosclerosis have an increased risk for developing coronary artery disease (CAD), especially at young ages. They may derive the greatest benefit from traditional preventive strategies and strategies targeting novel,emerging risk factors. Because CAD is a complex, multifactorial disorder, global risk assessment has been recognized as an effective approach in preventing CAD and its manifestations. The systematic collection and interpretation of family history information is currently the most appropriate screening approach to identify individuals with genetic susceptibility to CAD. Much of the familial aggregation of CAD might be explained by familial aggregation of established risk factors and emerging CAD risk factors. Tests to assess genetic risk for CAD are primarily biochemical analyses that measure the different pathways involved in development and progression of disease. Some of these can guide and explain responses to treatment.

Risk factors for cardiovascular disease in pediatric renal transplant recipients

About 1,000 children develop end-stage renal disease (ESRD) each year in the United States and about 5,000 children are currently receiving dialysis. Children who develop ESRD are eligible to receive renal replacement therapy, including renal transplantation. There are inherent risks associated with transplantation, including renal insufficiency, infections, post-transplant lymphoproliferative disorder, and cardiovascular disease (CVD). Potential risk factors for CVD in pediatric renal transplant recipients include renal insufficiency, hyperlipidemia, hyperhomocysteinemia, inflammation, malnutrition, anemia, and hyperglycemia/insulin resistance. Despite evidence that many children may possess various risk factors for CVD post-renal transplantation, there are very few studies that have attempted to assess the link between these risk factors and CVD in pediatric renal transplant recipients.

Progress in Clinical Neurosciences: Pharmacotherapies for the Secondar Prevention of Stroke

Stroke is a leading cause of mortality and long-term disability worldwide. Survivors of a previous stroke or transient ischemic attack are vulnerable to further cerebrovascular events, as well as myocardial infarction, peripheral vascular disease, congestive heart failure and vascular death. Traditional approaches to the secondary prevention of stroke have included aspirin after ischemic stroke, warfarin for stroke associated with cardioembolic sources, and carotid endarterectomy for eligible candidates with significant carotid artery stenosis. In recent years, much evidence has emerged to support a broader array of pharmacotherapies, including newer antiplatelet agents, lipid lowering drugs, and several classes of blood pressure lowering therapies. Also under study are B vitamins for patients with cerebrovascular disease and hyper-homocysteinemia, and oral direct thrombin inhibitors for high-risk patients with atrial fibrillation. We review the literature to determine the clinical significance of these therapies, and provide recommendations regarding their use in the prevention of recurrent stroke.

High-density lipoprotein and homocysteine levels correlate inversely in preeclamptic women in northern Nigeria

BACKGROUND

Preeclampsia/eclampsia is one of the most common complications of pregnancy. It is a cause of high morbidity for both mother and fetus, especially in developing countries. In a recent survey conducted in Gombe, Nigeria, eclampsia was found to be a major cause of maternal mortality (24.2%), second only to obstetric hemorrhage (27.1%). Previous studies have produced contradictory findings regarding total homocysteine (tHcy) levels in women with preeclampsia/eclampsia and there is little information about the relationship between particular serum lipids and tHcy. The objective of this study in Gombe was to compare the levels of serum lipids and homocysteine in healthy pregnant women and women with preeclampsia/eclampsia in Nigeria.

METHODS

The experimental subjects included 43 women with preeclampsia/eclampsia and 130 healthy pregnant women served as controls. The criteria for preeclampsia/eclampsia included the following: hypertension (blood pressure > 140/90 mmHg), total protein (> 190 mg/g creatinine), and edema. Blood sera obtained from patients and controls attending the prenatal clinics at the Specialist Hospital and the Federal Medical Center in Gombe were analyzed for tHcy, total cholesterol, triglycerides, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, antioxidant capacity, folate, and vitamin B-12.

RESULTS

The mean tHcy concentration for the preeclamptic/eclamptic women was greater than that of the controls (10.1 vs. 8.4 micromol/l, respectively, p = 0.01). The mean concentrations of LDL-cholesterol and triacylglycerols were not different between the two groups. However, the mean HDL-cholesterol level was higher in the healthy pregnant women compared with the preeclamptic/eclamptic women (1.64 vs. 1.42 mmol/l, respectively, p = 0.02). The HDL-cholesterol concentration was correlated inversely with the tHcy concentration (p = 0.001, r = 0.51). Total homocysteine was not linked with either serum folate or vitamin B-12.

CONCLUSIONS

These results show that preeclampsia/eclampsia is associated with increased tHcy levels and that HDL levels are depressed in Nigerian women with this hypertensive, pregnancy associated disorder.

Vascular disease and inflammation

The past decade has witnessed a dramatic shift in the understanding of the causes of atherosclerotic vascular disease. What was once considered to be a process of abnormal lipid deposition in the vascular wall is now understood to be a dynamic inflammatory process from inception through plaque growth, rupture and ultimately thrombosis. This article reviews the basic science research that supports this growing body of epidemiologic data and discusses the inflammatory markers that predict future clinical events,as well as the pharmacologic success in therapies that specifically target inflammation.

Serum homocysteine in relation to mortality and morbidity from coronary heart disease: a 24-year follow-up of the population study of women in Gothenburg

BACKGROUND

Elevated serum total homocysteine (tHcy) is an established risk factor for cardiovascular disease (CVD), especially in men. However, there are few prospective population studies on female cohorts, and none of these has been longer than 13 years.

METHODS AND RESULTS

The Population Study of Women in Gothenburg began in 1968/1969, at which time a representative population-based cohort of women aged 38, 46, 50, 54, and 60 years was recruited. The present cohort is a prospective follow-up of 1368 women in the original cohort for whom blood samples were stored and who were free of previous acute myocardial infarction (AMI) at the 1968/1969 baseline. Homocysteine was analyzed in 2001 with frozen serum from the baseline study and related to AMI incidence and mortality during 24 years of follow-up. Cox regression analyses were used with adjustment for age, traditional risk factors, and tHcy modifiers. For the fifth tHcy quintile, relative risk was 1.86 (95% CI 1.06 to 3.26) for AMI and 5.14 (95% CI 2.22 to 11.92) for death due to AMI. Age-standardized Kaplan-Meier plots for the fifth tHcy quintile versus others showed significant differences both for AMI and for death due to AMI that were apparent after 15 years of follow-up.

CONCLUSIONS

Homocysteine in middle-aged women is an independent risk factor for myocardial infarction and in particular mortality due to myocardial infarction. The study illustrates that long-term prospective studies might be necessary to show effects of homocysteine levels on AMI morbidity and mortality in women.

Risk factors for coronary heart disease in women

The increased focus on risk factors for CHD in women has greatly improved our understanding of this disease in women. The evidence against cigarette smoking, elevated serum cholesterol, and high blood pressure is strong, and sustained campaigns are underway to prevent and appropriately manage these conditions. The importance of adequate physical activity and weight control is well established, and research continues on other emerging risk factors. The focus of future research will be on clarifying the role of these factors, particularly for women and ethnic minorities.

Influence of endothelial nitric oxide synthase gene polymorphisms (G894T, 4a4b, T-786C) and hyperhomocysteinemia on the predisposition to acute coronary syndromes

BACKGROUND

Nitric oxide is an endothelium-derived relaxing factor that contributes significantly to vascular tone regulation. In this study we investigated the role of endothelial nitric oxide synthase (eNOS) polymorphisms as predisposing factors to acute coronary syndromes (ACS).

METHODS

In 477 consecutive patients admitted to the coronary intensive therapy unit of the University of Florence and in 537 unrelated controls, genotypes of eNOS G894T and T-786C polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphism analysis and the repeat polymorphism 4a/4b was analyzed by polymerase chain reaction. The genotype distribution was in Hardy-Weinberg equilibrium for all variants.

RESULTS

The multivariate analysis showed that the homozygosity for the eNOS 4a rare variant represented an independent predisposition factor to ACS (odds ratio [OR] 2.5, 95% CI 1.1-5.4, P =.02) and in particular influenced the risk of acute myocardial infarction (OR 3.6, 95% CI 1.2-11.5, P =.03). Subjects carrying the 4a4a/-786CC haplotype showed a higher predisposition to the disease (OR 6.1, 95% CI 1.3-29.6, P =.02). The contemporary presence of hyperhomocysteinemia and homozygosity for the -786C variant influenced the predisposition to ACS (OR 9.1, 95% CI 1.7-46.7, P =.008).

CONCLUSIONS

The presence of the eNOS 4a4a genotype represents a predisposing condition to ACS and in particular to acute myocardial infarction. Moreover, our data provide the evidence that the -786CC pattern modulates the susceptibility to ACS in 4a4a homozygotes and in hyperhomocysteinemic patients.

Plant Sterol-Fortified Orange Juice Effectively Lowers Cholesterol Levels in Mildly Hypercholesterolemic Healthy Individuals

Objective— Hypercholesterolemia is a major risk factor for coronary artery disease. Therapeutic lifestyle changes include dietary modifications such as inclusion of phytosterols, which effectively lowers low-density lipoprotein (LDL) cholesterol in margarines and other fats. Their effectiveness in nonfat moieties is not yet established. The aim of this study was to examine if phytosterols alter the plasma lipoprotein profile when incorporated into nonfat orange juice.

Methods and Results— After a 2-week run-in phase with orange juice, 72 mildly hypercholesterolemic healthy subjects were randomized to receive either placebo orange juice (placebo OJ) or plant sterol-fortified orange juice (sterol OJ) (2g/d) for 8 weeks. Fasting blood was obtained at baseline, after 2 weeks of OJ, and after 8 weeks of placebo/sterol-OJ supplementation. Sterol OJ supplementation significantly decreased total (7.2%), LDL (12.4%), and non-high-density lipoprotein (HDL) cholesterol (7.8%) compared with baseline and compared with placebo OJ ( P <0.01). Apolipoprotein B levels were significantly decreased (9.5%) with sterol OJ. There were no significant changes in HDL cholesterol or triglycerides with the sterol OJ. While folate and B12 levels significantly increased, homocysteine levels were unchanged.

Conclusions— Orange juice fortified with plant sterols are effective in reducing LDL cholesterol and could easily be incorporated into the therapeutic lifestyle changes dietary regimen.

Comparing the ESA HPLC total homocysteine assay with electrochemical detection to the CDC in-house HPLC assay with fluorescence detection

BACKGROUND

Environmental science has developed a simple high performance liquid chromatography (HPLC) assay with electrochemical detection for total homocysteine (tHcy) measurement that does not require derivatization of free thiols. We evaluated this method and compared it with the CDC HPLC assay with fluorescence detection (FD).

METHODS

tHcy is measured after reduction of disulfides/protein-bound thiols and protein precipitation using four channels of an ESA CoulArray detector. L-homocystine is used as calibrator, penicillamine as internal standard.

RESULTS

Aqueous calibration of the ESA assay resulted in overestimation of tHcy by approximately 30% compared to the HPLC-FD method. Calibration in plasma alleviated the matrix effect. The within- (n=3) and between-run (n=20) imprecision was <6%, the linearity up to 100 micromol/l was excellent, and the recovery of tHcy added to plasma was nearly complete (98.7%+/-2.3%). Good correlation was observed between both methods for 266 plasma samples. The ESA assay showed a minimal negative bias of 0.28 micromol/l (3.3%).

CONCLUSION

The ESA tHcy assay performed well in terms of accuracy and precision, and showed good agreement with the CDC HPLC-FD assay when calibrated in plasma. The major advantage of this assay is that it does not require sample derivatization. Disadvantages include instability of the prepared samples for prolonged storage and matrix effects.

Folate and homocysteine interrelationships including genetics of the relevant enzymes

PURPOSE OF REVIEW

Inadequate folate status has been linked to risk of a wide range of adverse health conditions throughout life, from birth defects and complications of pregnancy to cardiovascular disease, cancer and cognitive dysfunction in the elderly. In many instances these risks are manifested through elevated plasma homocysteine. This review focuses on current research into the contribution of genetic variability to folate status and disease predisposition.

RECENT FINDINGS

Some dozen potentially important polymorphisms in folate-related genes have been examined for disease associations or for their role in determining the level of plasma homocysteine. In most instances, the effects are either modest, not significant, or undetectable. However, the mechanism by which the 677C-->T variant of methylenetetrahydrofolate reductase determines homocysteine status has become clearer with the elucidation of a critical role for riboflavin in modulating the plasma homocysteine of TT homozygotes. Moreover, several new metaanalyses have confirmed an association of this variant with vascular disease, probably through low folate status and elevated plasma homocysteine.

SUMMARY

There are enormous difficulties in attempting to assess the contribution of minor genetic variability to nutrient status, against major background differences due to ethnicity, age, gender, lifestyle, dietary habits and disease status. Nevertheless, this is an important goal in the future management of chronic multifactorial disease. The present research into the genetic components of folate and homocysteine variability is paving the way towards an eventual capacity to ensure optimal folate status in every individual and, consequently, to reduce their risk of developing such diseases.

Analytical performance and method comparison study of the total homocysteine fluorescence polarization immunoassay (FPIA) on the AxSYM analyzer

A fluorescence polarization immunoassay (FPIA) has been commercially released for routine large-scale testing of total homocysteine (tHcy) on the AxSYM analyzer. We evaluated the analytical performance of the AxSYM tHcy FPIA and compared it with the well established high-performance liquid chromatography (HPLC) and IMx tHcy FPIA methods. Homocysteine concentrations were measured by AxSYM and IMx tHcy FPIA and by a rapid isocratic HPLC method with fluorescence detection. Coefficient of variation (CV) of total imprecision for AxSYM tHcy was ≤5%, mean dilution recovery 102%, analytical sensitivity 0.70 μmol/l and linearity was good up to 1:8 dilution. Spearman rank correlations, rho, were 0.83 (p<0.0001) for AxSYM vs. HPLC, 0.97 (p<0.0001) for AxSYM vs. IMx and 0.83 (p <0.0001) for IMx vs. HPLC. Passing and Bablok regression Y-intercepts and slopes were: 2.944/0.937 (AxSYM vs. HPLC), −0.367/1.142 (AxSYM vs. IMx) and 2.632/0.805 (IMx vs. HPLC). Corresponding mean differences (AxSYM-Comparison Assay) recorded over a 5–50 μmol/l measured range were 1.80, −0.73 and 2.53 μmol/l. AxSYM tHcy FPIA's first rate precision, supported by the complete automation of the AxSYM analyzer, makes it fit for routine use and suitable for laboratories requiring homocysteine high-throughput testing capabilities.

Comparison of the effect of oral and transdermal hormone therapy on fasting and postmethionine homocysteine levels

OBJECTIVE

To compare the modifications on basal and post-methionine homocysteine (Hcy) levels induced by transdermal vs. oral continuous combined hormone therapy (HT).

DESIGN

Prospective randomized study.

SETTING

Outpatient service at university hospital.

PATIENT(S)

Twenty-four healthy postmenopausal women.

INTERVENTION(S)

Six-month administration of transdermal (50 microg/d of E(2) and 140-170 microg/d of norethisterone [NET] acetate; n = 12) or oral (2 mg of E(2) and 1 mg of NET acetate; n = 12) HT.

MAIN OUTCOME MEASURE(S)

Fasting levels of Hcy, cysteine (Cys), folate, and vitamin B12. Post-methionine Hcy concentrations.

RESULT(S)

During HT, a slight decrease of fasting Hcy (8.9 [6.7; 15.2] micromol/L vs. 8.3 [4.9; 12.0] micromol/L) and fasting Hcy/Cys, a possible index of Hcy trans-sulfuration (0.061 [0.039; 0.107] micromol/L vs. 0.048 [0.032; 0.093] micromol/L) was observed. Modifications were similar in the transdermal and oral group. Net decreases of Hcy and Hcy/Cys observed during HT were related linearly to pretreatment values (r = 0.821 and r = 0.775, respectively), and were significant for Hcy above, but not below, 9 micromol/L. Transdermal (33.5 [27.5; 75.9] micromol/L vs. 28.4 [17.4; 48.9] micromol/L) or oral HT (36.1 [17.7; 74.8] micromol/L vs. 29.9 [17.5; 50.3] micromol/L), decreased, similarly, post-methionine Hcy levels.

CONCLUSION(S)

Similarly to oral, transdermal HT reduces post-methionine Hcy and fasting Hcy when it is elevated.

Determination of folate vitamers in human serum by stable-isotope-dilution tandem mass spectrometry and comparison with radioassay and microbiologic assay

BACKGROUND

Current clinical methods for folate give different results and cannot measure the various forms of folate. We developed an isotope-dilution tandem mass spectrometric method coupled to liquid chromatography (LC/MS/MS) as a candidate reference method for 5-methyltetrahydrofolic acid (5MeTHF), 5-formyltetrahydrofolic acid (5FoTHF), and folic acid (FA) in human serum.

METHODS

We quantitatively isolated folates from 275 microL of serum with a phenyl solid-phase extraction cartridge, then detected and quantified them in stabilized serum extracts by positive-ion electrospray ionization LC/MS/MS. We used an isocratic mobile phase of acetic acid in organic solvent on a C(8) analytical column. (13)C-labeled folates were used as internal standards.

RESULTS

Limits of detection in serum were 0.13 (5MeTHF), 0.05 (5FoTHF), and 0.07 (FA) nmol/L. Within- and between-run imprecision (CV) was <7% for 5MeTHF and <10% for 5FoTHF at concentrations >0.5 nmol/L, and <10% for FA at concentrations >2.0 nmol/L. Total folate (TFOL) concentrations determined by competitive protein binding radioassay were approximately 9% lower than results obtained with LC/MS/MS. The microbiologic assay gave approximately 15% higher TFOL results with FA calibrator and no difference with 5MeTHF calibrator. The mean (SD) [range] TFOL in 42 sera was 35.5 (17.8) [6.5-75.6] nmol/L. Thirty-two samples with TFOL <50 nmol/L had, on average, 93.3% 5MeTHF, 2.3% FA, and 4.4% 5FoTHF. Ten samples with TFOL >50 nmol/L had, on average, 81.7% 5MeTHF, 15.7% FA, and 2.5% 5FoTHF.

CONCLUSIONS

This stable-isotope-dilution LC/MS/MS method can quantify 5MeTHF, 5FoTHF, and FA in serum. Currently used clinical assays agree with this candidate reference method.

Genetically Determined Procoagulant States and Heparin Use

The propensity for both arterial and venous thrombotic disorders involves a genetic predetermination that operates In concert with environmental factors or triggers. Appropriate clinical assessment and therapeutic recommendations for patients with thrombosis requires a thorough knowledge of genetic variables that influence this propensity. This review focuses on the pathophysiology, natural history, and molecular biology of defined thrombophilic risk factors relevant to the care of patients with thrombotic disorders.

Niacin, lipids, and heart disease

Niacin is the most effective medication in current clinical use for increasing high-density lipoprotein (HDL) cholesterol. It has the broadest effect on the lipid profile, reducing all atherogenic apolipoprotein (apo) B and increasing all antiatherogenic apo AI-containing lipoproteins, resulting in significant reduction in atherosclerotic complications and total mortality in trials. Recent research indicates novel major target sites of action in the liver to 1) directly inhibit diacylglycerol acyltransferase 2 (DGAT2), explaining its effect on triglycerides and apo B lipoproteins, and 2) inhibit the HDL apo AI catabolism pathway, resulting in higher HDL levels. Such information may lead to new drug discovery and supply the rationale for combination with other lipid regulators that are known to have different mechanisms of action. Trial evidence shows that niacin is not only safe to use in persons with diabetes, but that its combination with 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG CoA) reductase inhibitors (statins) is also safe and effective. Recently, a new formulation of niacin has made it easier to tolerate and administer. Clinical trials are needed to determine whether niacin in combination with other lipid-modulating agents decreases the risk of cardiovascular events beyond the approximately 30% that has been noted with monotherapy.

The clinical pharmacology of ageing

The ageing of populations and individuals continues to be as vital, yet to some extent as neglected, a topic in pharmacology and therapeutics as was first realised about 30 years ago. In parallel with the realisation of the predicted demographic shifts in both the developed and developing world, there have since been major developments in the basic biological concepts of ageing, in the physiology of ageing, in the study of pathogenetic mechanisms underlying a variety of age-associated disorders and syndromes, and in the evidence base for therapeutic intervention in elderly patient populations. These all present new challenges both in the practical delivery of effective medical care and in clinical and biological research. The scale of prescribing for an ageing population has continued to rise as anticipated. Whether there has now been any improvement in the quality or rationality of prescribing, or in the previously demonstrated unacceptable level of susceptibility to adverse drug reactions in the (now expanded) older patient population is largely unknown. We urgently need to find out using up-to-date research methods. National and international guidelines for drug development and regulation have more recently been followed by broader policy initiatives on prescribing for older people, but the impact of these on standards of medication use and on clinical outcome remains to be seen. A new series in this journal on the clinical pharmacology of ageing is timely. The required focus and framework for research have often tended in the past to emerge as afterthoughts behind the merely disease specific, and it is to be hoped that a sequential review of some of the key topics may help to re-ignite a more sound and less short-sighted agenda than previously.

Comparative effects of atorvastatin, simvastatin, and fenofibrate on serum homocysteine levels in patients with primary hyperlipidemia

Hyperhomocysteinemia is regarded as an independent risk factor for cardiovascular disease. Lipid-lowering agents, such as fibrates, can modify homocysteine levels. However, less is known about the effect of statin therapy on homocysteine. The authors compared the effects of atorvastatin (40 mg/day), simvastatin (40 mg/day), and micronized fenofibrate (200 mg/day) on the serum concentrations of total homocysteine, vitamin B12, and folic acid in patients with primary hyperlipidemia. A total of 128 patients with primary hyperlipidemia (total cholesterol > 240 mg/dL and triglycerides < 350 mg/dL) were assigned to atorvastatin, simvastatin, or fenofibrate. Serum lipid and metabolic parameters were measured at baseline and at 6 and 12 weeks of treatment. Homocysteine correlated positively with serum creatinine and uric acid levels and inversely with serum folic acid levels. All treatment modalities reduced total, low-density lipoprotein (LDL) cholesterol, and triglyceride concentrations. High-density lipoprotein (HDL) cholesterol levels significantly increased only in the fenofibrate-treated patients (47.9 +/- 12.5 vs. 50.7 +/- 12.6 vs. 51.2 +/- 12.8 mg/dL, p < 0.01). Atorvastatin and fenofibrate treatment resulted in a significant reduction of serum uric acid levels (5.3 +/- 1.6 vs. 4.9 +/- 1.4 vs. 4.8 +/- 1.4 mg/dL, p < 0.0001 for atorvastatin; 5.6 +/- 1.6 vs. 4.3 +/- 1.4 vs. 4.4 +/- 1.4 mg/dL, p < 0.0001 for fenofibrate). Homocysteine levels were significantly increased only by fenofibrate (10.3 +/- 3.3 vs. 14.1 +/- 3.8 vs. 14.2 +/- 3.6 microU/L, p < 0.001) but did not change from baseline following statin treatment. Neither statins nor fenofibrate had any effect on serum vitamin B12 and folic acid levels. In contrast to fenofibrate, therapeutic dosages of atorvastatin and simvastatin have a neutral effect on serum homocysteine levels, which is in favor of their "cardioprotective" properties.

Effect of folic acid on fenofibrate-induced elevation of homocysteine and cysteine

BACKGROUND

An elevated total plasma homocysteine (tHcy) level is considered to be an independent risk factor for atherosclerosis. It has been reported that lipid-lowering therapy with fibric acid derivatives (fibrates) increases tHcy and total plasma cysteine (tCys) levels. The aim of this study was to determine whether therapy with folic acid, a potent tHcy-lowering agent, could modify the fenofibrate-induced elevation of plasma aminothiols.

METHODS

Patients with combined hyperlipidemia (n = 37) were randomized to receive 9 weeks of treatment with micronized fenofibrate 200 mg/day (F group) or fenofibrate 200 mg/day plus folic acid 10 mg/every other day (F+F group). tCys and tHcy levels were determined before and after the therapy with high performance liquid chromatography.

RESULTS

The tHcy level increased significantly in the F group by 51.3% and in the F+F group by 14.6% (between-group difference P =.001). Total plasma cysteine (tCys) increased similarly after both treatments (P =.72). The serum creatinine level increased in the F group by 20.7% and in F+F group only by 9.8% (P =.04). The increase of tHcy level in F group correlated with an increase of tCys and creatinine levels (r = 0.74 and 0.64, respectively). The effects on the lipid profile did not differ by treatment group.

CONCLUSIONS

Folic acid effectively reduces the fenofibrate-induced elevation of tHcy and creatinine, but it does not affect the elevation of the tCys. Folic acid has neutral effect on the lipid-lowering action of fenofibrate. Clinical efficacy of fenofibrate might be improved by folic acid coadministration.

The increasing impact of laboratory medicine on clinical cardiology

The practice of cardiology continues to evolve along with a better understanding of the pathophysiology of cardiovascular disease and the development of new therapeutic procedures. Consequently, new demands are being made on the in vitro diagnostics industry to improve the performance of existing cardiac markers and to develop novel markers for new cardiac disease indications. Indeed, in the last 20 years there has been a progressive increase in new laboratory tests for markers of cardiac diseases. Several highly sensitive and/or specific assays for the detection of myocardial ischemic damage as well as some immunoassays for cardiac natriuretic hormones, now considered a reliable marker of myocardial function, have become commercially available. In parallel, a growing number of some novel risk factors, which can be assessed and monitored by laboratory methods, have been added to the classical risk factors for cardiovascular disease. Finally, the recent explosion of genetic analysis may soon place at the clinical cardiologist's disposal many laboratory tests for defining the diagnosis at the molecular level, assessing new risk factors, and better targeting the pharmaceutical approaches in patients with cardiovascular disease. In the present article, after a brief description of the analytical tests included in these four groups, each group's impact on clinical cardiology is discussed in detail.

Periconceptional use of folic acid supplements in Oslo

BACKGROUND

Periconceptional supplementation with folic acid has been shown to decrease the occurrence of neural tube defects (NTD). A daily supplement of 400 micro g folic acid from the month before pregnancy and the first 2 to 3 months of pregnancy is recommended in Norway. We wanted to evaluate the use of folic acid supplements among pregnant women in Oslo, and to explore demographic factors that were associated with periconceptional intake.

METHODS

All women attending antenatal ultrasound screening at the two main obstetric departments in Oslo during 3 months in 2001 were invited to answer questions regarding folic acid supplementation before and during their present pregnancy.

RESULTS

A total of 1541 women (91, 5%) participated in the study, of which 26% were nonwestern immigrants. Only 17% of all women had started the folic acid supplementation preconceptionally (22% of the nonimmigrant vs. 2% of the immigrant population). Folic acid had been used by 58% at some time during the present pregnancy (73% of the nonimmigrant vs. 19% of the immigrant population). Regression analysis demonstrated that the difference in periconceptional use of folic acid between the two population groups could not be explained by registered demographic factors other than immigrant status.

CONCLUSIONS

Most pregnant women in Oslo do not use folic acid as recommended and a dramatically low usage is seen among the immigrant population, indicating that more widespread information is necessary. Furthermore, fortification of cereals with folic acid should be considered to secure a sufficient intake of folic acid in all fertile women.

Genetic evaluation for coronary artery disease

There is substantial evidence that genetic factors contribute to coronary artery disease (CAD). Currently, family history collection and interpretation is the best method for identifying individuals with genetic susceptibility to CAD. Family history reflects not only genetic susceptibility, but also interactions between genetic, environmental, cultural, and behavioral factors. Stratification of familial risk into different risk categories (e.g., average, moderate, or high) is possible by considering the number of relatives affected with CAD and their degree of relationship, the ages of CAD onset, the occurrence of associated conditions, and the gender of affected relatives. Familial risk stratification should improve standard CAD risk assessment methods and treatment guidelines (e.g., Framingham CAD risk prediction score and Adult Treatment Panel III guidelines). Individuals with an increased familial risk for CAD should be targeted for aggressive risk factor modification. Individuals with a high familial risk might also benefit from early detection strategies and biochemical and DNA-based testing, which can further refine risk for CAD. In addition, individuals with the highest familial risk might have mendelian disorders associated with a large magnitude of risk for premature CAD. In these cases, referral for genetic evaluation should be considered, including pedigree analysis, risk assessment, genetic counseling and education, discussion of available genetic tests, and recommendations for risk-appropriate screening and preventive interventions. Research is needed to assess the feasibility, clinical validity, clinical utility, and ethical, legal, and social issues of an approach that uses familial risk stratification and genetic evaluation to enhance CAD prevention efforts.

Dyslipidemia treatment: current considerations and unmet needs

Monumental evidence from clinical trials indicates an approximately 30% reduction in atheroslcerotic cardiovascular disease (ASCVD) risk using monotherapy with lipid-regulating drugs in dyslipidemic patients. In order to achieve greater reductions in risk, other approaches are necessary, including improvements in technology designed to assess ASCVD risk. Recent preliminary, but encouraging evidence indicates that by combining drugs that have different mechanisms of action on lipid metabolism yields not only an additive effect on the lipoprotein spectrum, but also reduces ASCVD events. New studies indicate that niacin potently increases high-density lipoproteins (HDL) by inhibiting HDL catabolism and decreases hepatic production of atherogenic very-low- and low-density lipoproteins by inhibiting the key enzyme for triglyceride synthesis (diacylglycerol acyltransferase). Statins, fibrates, bile acid sequestrants and ezetimibe have mechanisms that are different. Combination therapy using statins and niacin not only safely corrects dyslipidemia, but also yields ASCVD risk reduction significantly in excess of the 30% seen with monotherapy. Newer drugs with different mechanisms of action or combinations of new formulations have recently become available. Drug discovery research is likely to yield additional agents. Clinical trials focused on combination therapies to reduce ASCVD risk well beyond 30% need to be conducted to establish the rationale for further reducing the incidence of the primary cause of death today.

Effects of folic acid supplementation on inflammatory and thrombogenic markers in chronic smokers. A randomised controlled trial

INTRODUCTION

Cigarette smoking may induce pro-inflammatory and pro-thrombotic changes. It is not known whether these abnormalities are caused at least partly by increased homocysteine levels. We investigated whether lowering homocysteine by folic acid supplementation might reduce the plasma concentration of inflammatory and thrombogenic markers in chronic smokers.

MATERIAL AND METHODS

Twenty-four healthy cigarette smokers (age 37.8+/-2.5 years, mean+/-SEM) were randomly assigned to 4 weeks of folic acid 5 mg/day or placebo. The following parameters were measured before and after treatment: (1) markers of inflammation (C-reactive protein, CRP, and white cell count, WCC); (2) blood coagulation screen (Activated Partial Thromboplastin time Ratio, APTR, and International Normalized Ratio, INR); (3) pro-thrombotic markers (fibrinogen, factor VIII coagulant activity, VIII:C, von Willebrand factor, vWF, and D-dimer).

RESULTS

Folic acid induced a significant reduction in homocysteine (10.8+/-0.6 vs. 8.2+/-0.5 micromol/l, p<0.001), plasma fibrinogen (3.15+/-0.14 vs. 2.87+/-0.14 g/l, p<0.05), and D-dimer (102+/-44 vs. 80+/-26 microg/l, p<0.05) concentrations. By contrast, no significant changes were observed in CRP (2.2+/-0.7 vs. 1.7+/-0.7 mg/l), WCC (7.2+/-0.5 vs. 6.8+/-0.5 10(9) cells/l), APTR (0.91+/-0.02 vs. 0.93+/-0.02), INR (0.92+/-0.01 vs. 0.91+/-0.01), vWF (103+/-8 vs. 102+/-9 U/dl), and VIII:C (120+/-8 vs. 107+/-8 U/dl) levels. Changes in folic acid plasma concentrations were significantly and negatively correlated with changes in fibrinogen (r=-0.48, p=0.01) but not with changes in D-dimer (r=-0.15, p=0.5) levels. Changes in plasma homocysteine concentrations did not correlate with changes in either fibrinogen or D-dimer. No significant changes in homocysteine, inflammatory and thrombogenic markers were observed in the placebo group.

CONCLUSIONS

Short-term folic acid supplementation had no significant effects on inflammatory markers but induced a significant reduction in plasma fibrinogen and D-dimer concentrations in healthy chronic smokers. Thus, folic acid might have an anti-thrombotic effect in this high-risk group independent of the homocysteine lowering effect.