Homocysteine

Excess homocysteine inhibits pancreatic β-cell secretory function by repressing Zbtb20 expression

Homocysteine (Hcy) is a sulfur-containing amino acid. An elevated level of Hcy is a risk factor for diabetes development. However, the mechanism of its effect on pancreatic β-cell function is unclear. In this study, we constructed a hyperhomocysteinemia (HHcy) mouse model by feeding mice a high methionine diet (HMD). The mice suffered impaired glucose tolerance and reduced insulin secretion. Furthermore, at the cellular level, INS1 cells exhibited impaired insulin secretory function after the Hcy intervention. Transcriptomics revealed that Zbtb20 expression was downregulated and the downstream gene Fbp1 was upregulated in HHcy-induced mice compared with mice fed with normal diet. Insulin secretion could be restored by Zbtb20 overexpression or fructose 1,6-bisphosphatase (FBPase) activity inhibition in INS1 cells. In conclusion, our study suggested that Hcy inhibited the insulin secretory function of pancreatic β-cells by suppressing Zbtb20 expression, leading to the development of diabetes. Zbtb20 may be a key target in the development of diabetes associated with elevated Hcy levels.

Higher blood selenium level is associated with lower risk of hyperhomocysteinemia in the elderly

BACKGROUND AND AIMS

Earlier studies have reported inconsistent association between selenium (Se) and homocysteine (Hcy) levels, while no evidence could be found from Chinese population. To fill this gap, we investigated the association between blood Se and hyperhomocysteinemia (HHcy) of rural elderly population in China.

METHODS

A cross-sectional study on 1823 participants aged 65 and older from four Chinese rural counties was carried out in this study. Whole blood Se and serum Hcy concentrations were measured in fasting blood samples. Analysis of covariance and restricted cubic spline models were used to examine the association between Se and Hcy levels. Logistic regression models were used to evaluate the risk of prevalent HHcy among four Se quartile groups after adjusting for covariates.

RESULTS

For this sample, the mean blood Se concentration was 156.34 (74.65) μg/L and the mean serum Hcy concentration was 17.25 (8.42) μmol/L. A significant non-linear relationship was found between blood Se and serum Hcy, the association was inverse when blood Se was less than 97.404 μg/L and greater than 156.919 μg/L. Participants in the top three blood Se quartile groups had significantly lower risk of prevalent HHcy compared with the lowest quartile group. When defined as Hcy> 10 μmol/L, the odds ratios and 95% confidence interval of HHcy were 0.600 (0.390, 0.924), 0.616 (0.398, 0.951) and 0.479 (0.314, 0.732) for Q2, Q3, and Q4 Se quartile groups compared with the Q1 group, respectively. When defined as Hcy≥ 15 μmol/L, the odds ratios and 95% confidence interval of HHcy were 0.833 (0.633, 1.098) and 0.827 (0.626, 1.092), 0.647 (0.489, 0.857) for Q2, Q3, and Q4 Se quartile groups compared with Q1 group.

CONCLUSIONS

Our findings suggest that higher blood Se level could be a protective factor for HHcy in the elderly.

Homocysteine-lowering interventions for preventing cardiovascular events

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Association between Stable Coronary Artery Disease and In Vivo Thrombin Generation

Background. Thrombin has been implicated as a key molecule in atherosclerotic progression. Clinical evidence shows that thrombin generation is enhanced in atherosclerosis, but its role as a risk factor for coronary atherosclerotic burden has not been proven in coronary artery disease (CAD) stable patients. Objectives. To evaluate the association between TAT levels and homocysteine levels and the presence of coronary artery disease diagnosed by coronary angiography in patients with stable CAD. Methods and Results. We included 95 stable patients admitted to the Haemodynamics Department, including 63 patients with significant CAD and 32 patients without. We measured the thrombin-antithrombin complex (TAT) and homocysteine concentrations in all the patients. The CAD patients exhibited higher concentrations of TAT (40.76 μg/L versus 20.81 μg/L, p = 0.002) and homocysteine (11.36 μmol/L versus 8.81 μmol/L, p < 0.01) compared to the patients without significant CAD. Specifically, in patients with CAD+ the level of TAT level was associated with the severity of CAD being 36.17 ± 24.48 μg/L in the patients with bivascular obstruction and 42.77 ± 31.81 μg/L in trivascular coronary obstruction, p = 0.002. Conclusions. The level of in vivo thrombin generation, quantified as TAT complexes, is associated with the presence and severity of CAD assessed by coronary angiography in stable CAD patients.

Homocysteine-lowering interventions for preventing cardiovascular events

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Versatile probes for the selective detection of vicinal-dithiol-containing proteins: design, synthesis, and application in living cells

Endogenous vicinal-dithiol-containing proteins (VDPs) that have two thiol groups close to each other in space play a significant importance in maintaining the cellular redox microenvironment. Approaches to identify VDPs mainly rely on monitoring the different concentration of monothiol and total thiol groups or on indirect labeling of vicinal thiols by using p-aminophenylarsenoxide (PAO). Our previous work has reported the direct labeling of VDPs with a highly selective receptor PAO analogue, which could realize fluorescence detection of VDPs directly in living cells. Herein, we developed a conjugated approach to expand detectable tags to nitrobenzoxadiazole (NBD), fluorescein, naphthalimide, and biotin for the synthesis of a series of probes. Different linkers have also been introduced toward conjugation of VTA2 with these functional tags. These synthesized flexible probes with various features will offer new tools for the potential identification and visualization of vicinal dithiols existing in different regions of VDPs in living cells. These probes are convenient tools for proteomics studies of various disease-related VDPs and for the discovery of new drug targets.

Homocysteine-lowering interventions for preventing cardiovascular events

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Polymorphisms in one-carbon metabolism pathway genes, urinary arsenic profile, and urothelial carcinoma

BACKGROUND

Gene polymorphisms in the one-carbon metabolism pathway could contribute to arsenic methylation capability through plasma folate and homocysteine metabolism, thereby increasing the susceptibility to urothelial carcinoma (UC) risk.

OBJECTIVES

The goal of our study was to evaluate the roles of gene polymorphisms in the one-carbon metabolism pathway in the carcinogenesis of UC.

METHODS

A hospital-based case-controlled study was conducted. The urinary arsenic profile was examined using high-performance liquid chromatography and hydride generator-atomic absorption spectrometry. Folate levels were measured using a competitive immunoassay kit. Genotyping was conducted using polymerase chain reaction-restriction fragment length polymorphism technique.

RESULTS

Patients with UC had higher urinary total arsenic, inorganic arsenic percentage (InAs%) and monomethylarsenic acid percentage (MMA%), and lower dimethylarsenic acid percentage (DMA%), plasma folate and homocysteine levels than controls. The correlations between folate and DMA%, and folate and homocysteine, were significant according to Pearson's correlation coefficients. Subjects carrying the 5,10-methylenetetrahydrofolate reductase (MTHFR) CT or TT genotype had a lower DMA% and lower folate levels than those carrying the CC genotype. Participants with the methionine synthase (MS) AA genotype had higher homocysteine levels than those with the AG or GG genotype. However, neither MTHFR nor MS gene polymorphisms were associated with UC risk.

CONCLUSIONS

Environmental factors played a more important role in UC carcinogenesis than MTHFR or MS gene polymorphism.

Homocysteine inhibits neoangiogenesis in mice through blockade of annexin A2-dependent fibrinolysis

When plasma levels of homocysteine (HC), a thiol amino acid formed upon methionine demethylation, exceed 12 muM, individuals are at increased risk of developing large vessel atherothrombosis and small vessel dysfunction. The annexin A2 complex (termed "A2") is the cell surface coreceptor for plasminogen and TPA and accelerates the catalytic activation of plasmin, the major fibrinolytic agent in mammals. We previously showed that HC prevents A2-mediated, TPA-dependent activation of plasminogen in vitro by disulfide derivatization of the "tail" domain of A2. We also demonstrated that fibrinolysis and angiogenesis are severely impaired in A2-deficient mice. We now report here that, although hyperhomocysteinemic mice had a normal coagulation profile and normal platelet function, fibrin accumulated in their tissues due to reduced perivascular fibrinolytic activity and angiogenesis was impaired. A2 isolated from hyperhomocysteinemic mice failed to fully support TPA-dependent plasmin activation. However, infusion of hyperhomocysteinemic mice with fresh recombinant A2, which localized to neoangiogenic endothelial cells, resulted in normalization of angiogenesis and disappearance of peri- and intravascular fibrin. We therefore conclude that hyperhomocysteinemia impairs postnatal angiogenesis by derivatizing A2, preventing perivascular fibrinolysis, and inhibiting directed endothelial cell migration. These findings provide a mechanistic explanation for microvascular dysfunction and macrovascular occlusion in individuals with hyperhomocysteinemia.

Homocysteine lowering interventions for preventing cardiovascular events

BACKGROUND

Cardiovascular disease such as coronary artery disease, stroke and congestive heart failure, is a leading cause of death worldwide. A postulated risk factor is elevated circulating total homocysteine (tHcy) levels which is influenced mainly by blood levels of cyanocobalamin (vitamin B12), folic acid (vitamin B9) and pyridoxine (vitamin B6). There is uncertainty regarding the strength of association between tHcy and the risk of cardiovascular disease.

OBJECTIVES

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

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (issue 3 2008), MEDLINE (1950 to August 2008), EMBASE (1988 to August 2008), and LILACS (1982 to September 2, 2008). We also searched in Allied and Complementary Medicine (AMED; 1985 to August 2008), ISI Web of Science (1993 to August 2008), and the Cochrane Stroke Group Specialised Register (April 2007). We hand searched pertinent journals and the reference lists of included papers. We also contacted researchers in the field. There was no language restriction in the search.

SELECTION CRITERIA

We included randomised clinical trials (RCTs) assessing the effects of HLI for preventing cardiovascular events with a follow-up period of 1 year or longer. We considered myocardial infarction and stroke as the primary outcomes. We excluded studies in patients with end-stage renal disease.

DATA COLLECTION AND ANALYSIS

We independently performed study selection, risk of bias assessment and data extraction. We estimated relative risks (RR) for dichotomous outcomes. We measured statistical heterogeneity using I(2). We used a random-effects model to synthesise the findings.

MAIN RESULTS

We included eight RCTs involving 24,210 participants with a low risk of bias in general terms. HLI did not reduce the risk of non-fatal or fatal myocardial infarction, stroke, or death by any cause (pooled RR 1.03, 95% CI 0.94 to 1.13, I(2) = 0%; pooled RR 0.89, 95% CI 0.73 to 1.08, I(2) = 15%); and pooled RR 1.00 (95% CI 0.92 to 1.09, I(2): 0%), respectively.

AUTHORS' CONCLUSIONS

Results from available published trials suggest that there is no evidence to support the use of HLI to prevent cardiovascular events.

Prevalence of nutrient deficiencies in bariatric patients

OBJECTIVE

The aims of this study were to determine the prevalence of nutrient deficiencies in patients who present for bariatric surgery, assess nutritional status after surgery, and compare these with preoperative levels.

METHODS

A retrospective study was conducted to identify preoperative and 1-year postoperative nutrition deficiencies in patients undergoing bariatric surgery. The screening included serum ferritin, vitamin D, vitamin B(12), homocysteine, folate, red blood cell folate, and hemoglobin. Results were available for 232 patients preoperatively and 149 patients postoperatively. Two-tailed chi(2) tests and paired-sample t tests were used.

RESULTS

Preoperatively, vitamin D deficiency was noted at 57%. The prevalence of abnormalities 1 year after roux-en-Y gastric bypass was higher compared with preoperative levels (P < .05). After surgery, anemia was detected in 17%, elevated homocysteine levels (women only) in 29%, low ferritin in 15%, low vitamin B(12) in 11%, and low RBC folate in 12%. Mean hemoglobin, ferritin, and RBC folate levels deteriorated significantly but remained well within normal ranges. The prevalence of vitamin D deficiencies decreased, but not significantly. In sleeve gastrectomy patients, mean ferritin levels decreased (P < .05), without any patient developing a deficiency.

CONCLUSION

Vitamin D deficiency is common among morbidly obese patients seeking bariatric surgery. Because the prevalence of micronutrient deficiencies persists or worsens postoperatively, routine nutrition screening, recommendation of appropriate supplements, and monitoring adherence are imperative in this population.

Prevalence and risk factors for neuropathy in a Canadian First Nation community

OBJECTIVE

The purpose of this study was to determine the prevalence of and risk factors for diabetic neuropathy in a Canadian First Nation population.

RESEARCH DESIGN AND METHODS

This was a community-based screening study of 483 adults. Measures included glucose, A1C, cholesterol, triglycerides, homocysteine, hypertension, waist circumference, height, weight, and foot examinations. Neuropathy was defined as loss of protective sensation determined through application of a 10-g monofilament.

RESULTS

Twenty-two percent of participants had a previous diagnosis of diabetes, and 14% had new diabetes or impaired fasting glucose (IFG). The prevalence of neuropathy increased by glucose level: 5% among those with normal glucose levels, 8% among those with new IFG and diabetes, and 15% among those with established diabetes (P < 0.01). Those with neuropathy were more likely to have foot deformities (P < 0.01) and callus (P < 0.001) than those without neuropathy. Among those with dysglycemia (>or=6.1 mmol/l), the mean number of foot problems for those with insensate feet was 3 compared with 0.3 among those with sensation (P < 0.001). In multivariate logistic regression female sex, low education, A1C, smoking, and homocysteine were independently associated with neuropathy, after controls for age.

CONCLUSIONS

Neuropathy prevalence is high, given the young age of our participants (mean 40 years) and was present among those with undiagnosed diabetes. The high number and type of foot problems places this population at increased risk for ulceration; the low level of foot care in the community increases the risk. Homocysteine is a risk factor that may be related to lifestyle and requires further investigation.

Should hyperhomocysteinemia be treated in patients with atherosclerotic disease?

Numerous retrospective and prospective observational studies support an association between elevated homocysteine and increased risk for myocardial infarction, stroke, and peripheral vascular disease. Although folic acid therapy substantially reduces homocysteine levels, recent large, randomized controlled trials failed to translate folic acid-induced homocysteine reduction into clinical benefit for the secondary prevention of cardiovascular events. These studies are compelling and have generated some newfound skepticism regarding a clinical role for folic acid therapy. Because these intervention trials have been limited to patients with mild hyperhomocysteinemia, the results of the trials imply that folic acid therapy may be best suited for individuals with more robustly elevated homocysteine levels. Furthermore, the potential benefit of folic acid therapy for primary prevention in individuals at low- or intermediate-risk for atherothrombotic disease has not been studied to date. Thus, at this time, folic acid therapy for borderline or mild hyperhomocysteinemia is not recommended. However, the role of folic acid therapy in patients with intermediate or severe hyperhomocysteinemia, or for primary prevention of cardiovascular diseases, remains unresolved.

Clinical relevance of plasma homocysteine levels in Taiwanese patients with coronary artery disease

Homocysteine (Hcy) has recently been considered as a risk factor for cardiovascular disease. Coronary artery disease (CAD) is the third most common cause of mortality in Taiwan. The objective of our present study is to delineate the relationship between the plasma Hcy level and CAD in Taiwanese using an improved enzymatic method. Blood samples were collected from 86 CAD patients, which include 38 patients with acute coronary syndrome (ACS) and 48 patients with stable CAD, and 89 controls. Plasma Hcy levels were measured by HPLC and enzymatic methods. Plasma Hcy levels were 8.27 +/- 1.74, 8.50 +/-1.88 and 11.76 +/- 4.58 muM in normal controls, patients with stable CAD and those with ACS, respectively. Plasma Hcy levels were elevated in the cohort of ACS patients, as compared with those of normal controls or patients with stable CAD. Within the CAD group, patients with the highest quartile Hcy level (10.18-23.73 muM) had a significantly higher odd ratio for ACS, as compared with those with the lowest quartile Hcy level after multivariate adjustment. Plasma Hcy concentration can be used as an independent risk factor of ACS, particularly for those with a history of CAD. Moreover, our improved enzymatic assay can be automated for large-scale screening of high-risk cohorts.

Homocysteine, folates, and the eye

Plasma homocysteine has been identified as a risk factor for arterial disease, retinal artery and vein occlusions, and other common eye diseases. The value of treating an elevated plasma homocysteine with folic acid for preventing further vascular disease has not been proven. Although secondary prevention of coronary artery disease using this approach has been unsuccessful, trials on primary prevention of stroke and loss of cognitive function with folic acid supplementation appear to be successful. Further trial data are awaited. In patients with premature retinovascular disease, the measurement of plasma homocysteine is suggested and reduction of elevated homocysteine with folic acid for secondary prevention of retinal arterial and venous occlusion. Meanwhile, the debate on fortification of flour for primary prevention of neural tube defects, which has already taken place in North America, continues in European countries. Such fortification could have an impact on primary and secondary prevention of vascular disease.