Homocysteine, B vitamins, and coronary artery disease

The association between vitamin B12, folate, homocysteine levels, and carotid intima-media thickness in children with obesity: a cross-sectional study

OBJECTIVES

We aimed to evaluate the association between vitamin B12, folate, homocysteine levels, and carotid intima-media thickness (CIMT) among children with obesity in whom vitamin deficiencies are more frequent.

METHODS

Herein, 100 children with obesity (58 girls) were included (age, 5-18 years). Height, weight, body mass index (BMI), waist circumference (WC), puberty stage, blood pressure, and biochemical values were collected from medical records; standard deviations (SDS) and percentiles were calculated. Obesity was defined as BMI SDS of >+2SDS. Vitamin B12 and folate levels of <300 pg/mL and <4.8 ng/mL, respectively, were considered deficient. A radiologist quantified measurements from the carotid artery.

RESULTS

Mean patient age was 12.52 ± 3.63 years. The mean weight SDS, BMI SDS, and WC/height were +3.37 ± 0.93, +2.93 ± 0.55, and 0.65 ± 0.05, respectively. In pubertal cases, insulin (p<0.001), the homeostatic model assessment for insulin resistance (HOMA-IR) (p=0.001) and homocysteine (p=0.002) levels were higher; vitamin B12 (p<0.001) and folate (p<0.001) levels were lower than those in prepubertal ones. WC and HOMA-IR correlated with CIMT; however, homocysteine levels were not correlated with CIMT.

CONCLUSIONS

In our study, pubertal cases had lower vitamin B12 and folate levels as well as higher homocysteine levels. Although no correlation was identified between homocysteine levels and CIMT, this condition may be related to our study group comprising children, who had a shorter duration of obesity than those in adults. As CIMT was higher in children/adolescents with increased WC, it is proposed that they need central obesity more frequently and carefully follow-up.

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.

Role of treatment-modifying MTHFR677C>T and 1298A>C polymorphisms in metformin-treated Puerto Rican patients with type-2 diabetes mellitus and peripheral neuropathy

BACKGROUND

The study was conducted to investigate potential association between MTHFR genotypes and diabetic peripheral neuropathy (DPN) in Puerto Ricans with type-2 diabetes mellitus (T2DM) treated with metformin. The prevalence of major MTHFR polymorphisms in this cohort was also ascertained.

METHODS

DNAs from 89 metformin-treated patients with T2DM and DPN were genotyped using the PCR-based RFLP assay for MTHFR677C>T and 1298A>C polymorphisms. Frequency distributions of these variants in the study cohort were compared to those reported for three reference populations (HapMap project) and controls (400 newborn specimens). Chi-square (or Fischer's exact) tests and odds ratios (OR) were used to assess association with DPN susceptibility risk (patients vs. controls) and biochemical markers (wild types vs. carriers).

RESULTS

Sixty-seven percent (67%) of participants carry at least one of these MTHFR polymorphisms. No deviations from Hardy-Weinberg equilibrium were detected. The genotype and allele frequencies showed statistically significant differences between participants and controls (p<0.0001 and p=0.03, respectively). Results suggest that 1298A>C but not 677C>T is associated with DPN susceptibility in this cohort (p=0.018). Different patterns of allelic dissimilarities are observed when comparing our cohort vs. the three parental ancestries. After sorting individuals by their carrier status, no significant associations were observed between these genetic variants (independently or combined) and any of the biochemical markers (HbA1c, folate, vitamin B12, homocysteine).

CONCLUSIONS

Prevalence of major MTHFR variants in Puerto Rican patients with T2DM is first time ever reported. The study provides further evidence on the use of this genetic marker as an independent risk factor for DPN.

The effect of IL-4 and MTHFR gene variants in ankylosing spondylitis

PURPOSE

Ankylosing Spondylitis (AS) is a chronic inflammatory rheumatic disease that characteristically affects the sacroiliac joints and the spine. The exact pathogenesis of AS remains poorly understood, but genetic factors play a key role in disease development. Several genes have been consistently associated with susceptibility to AS. This study was conducted in Turkish AS patients to determine the frequency of the methylenetetrahydrofolate reductase (MTHFR) gene C677T and interleukin-4 (IL-4) gene 70 bp variable number of tandem repeats (VNTR) variants, as well as their association with clinical characteristics.

METHODS

Genomic DNA obtained from 272 persons (122 AS patients and 150 healthy controls) was used in this study. Genomic DNA was isolated and genotyped using a polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) assay for the MTHFR C677T and IL-4 70 bp VNTR gene variants, which were determined using specific PCR primers.

RESULTS

There was statistically significant difference between the groups with respect to MTHFR genotype distribution (p = 0.02) and allele frequencies (p < 0.001). When we examined MTHFR and IL-4 genotype frequencies according to clinical characteristics, we found an association between the homozygous MTHFR TT genotype and ocular involvement, although this did not reach statistical significance (p = 0.02). However, we did not find any difference between the groups with respect to IL-4 genotype distribution or allele frequencies and clinical characteristics (p > 0.05).

CONCLUSION

Our findings suggest that there is an association of the MTHFR gene C677T polymorphism with the susceptibility of a person for development of AS. However, the IL-4 gene is not associated with AS within the same population.

Genetic polymorphisms in preoperative myocardial infarction

OBJECTIVE

This study compared plasminogen activator inhibitor 1 and methylenetetrahydrofolate reductase C677T and A1298C polymorphisms in patients with myocardial infarction with ST-segment elevation before undergoing to coronary artery bypass grafting, and in patients who had previously undergone coronary artery bypass grafting.

METHOD

Seventy patients with myocardial infarction with ST-segment elevation, scheduled to undergo coronary artery bypass grafting, were included in the study group, and 70 patients who had previously undergone coronary artery bypass grafting were included in the control group. Genetic polymorphisms were determined using real-time polymerase chain reaction methods.

RESULTS

Our data showed that there were no significant differences in plasminogen activator inhibitor 1 and methylenetetrahydrofolate reductase C677T and A1298C polymorphisms or allele frequencies between the 2 groups.

CONCLUSION

Plasminogen activator inhibitor 1 and methylenetetrahydrofolate reductase C677T and A1298C polymorphisms were not associated risk factors in patients who had myocardial infarction with ST-segment elevation and planned to have coronary artery bypass grafting.

Methylenetetrahydrofolate reductase C677T mutation in patients with alopecia areata in Turkish population

OBJECTIVE

Methylene-tetrahydrofolate reductase (MTHFR) is a key enzyme regulating folate metabolism and it is thought to influence DNA methylation and nucleic acid synthesis. Mutations in the MTHFR gene have been associated with several autoimmune disorders in previous studies. Alopecia areata (AA) is considered to be a tissue-specific autoimmune disease as the hair follicle has been targeted and antibodies to their own hair follicle structures have been developed. Since there is a common shared pathway between AA and other autoimmune disorders, we aimed to investigate a possible association between the MTHFR gene C677T mutation and AA susceptibility in the Turkish population.

METHODS

The study included 136 patients affected by AA and 130 healthy controls. Genomic DNA was isolated and genotyped using a polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) assay for the MTHFR gene C677T mutation.

RESULTS

The distributions of genotype and allele frequencies of MTHFR gene C677T mutation were statistically different between AA patients and the control group (p=0.036 and p=0.011, respectively). High differences were also observed when the patients and controls were compared according to CC versus CT+TT (p=0.012). CT+TT genotypes and T allele of MTHFR gene C677T mutation were found to be a susceptibility factor for AA in the Turkish population.

CONCLUSION

The results suggest that MTHFR gene C677T mutation may have an effect on the risk of alopecia areata in the Turkish population. This is the first study reporting the association between the MTHFR (C677T) genotype and AA.

Risk prediction-Homocysteine in Coronary Heart Disease

Majority of patients who experience a Coronary Heart disease event have one or more of the conventional risk factors for atherosclerosis and so do many people who have not yet experienced such an event. Thus predictive models based on conventional risk factors have lower than the desired accuracy, providing a stimulus to search for new factors to predict accurately the risk of CHD. In this regard newer risk factors like homocysteine, Lp(a), insulin resistances are the important ones and are called as 'novel risk factors'. The study was undertaken to find the prediction of CHD risk by homocysteine in comparison with other conventional risk factors. The data obtained suggests a very high sensitivity, specificity and accuracy with above 90% positive prediction value for homocysteine in CHD patients when compared to commonest conventional risk factors.

Implant overdentures and nutrition: a randomized controlled trial

We conducted a randomized clinical trial to determine whether providing simple mandibular implant overdentures (IODs) to elderly individuals would give them a significantly better nutritional profile than those who receive complete dentures (CDs). Two hundred fifty-five edentate patients > 65 yrs were randomly assigned to receive maxillary CDs and mandibular IODs (n = 128) or CDs (n = 127). Six-month and one-year post-treatment outcomes were blood plasma levels of homocysteine (tHcy), vitamin B12, vitamin B6, albumin, serum folate, and C-reactive protein concentrations, as well as dietary intake. The association between treatment and tHcy levels was not statistically significant. A decline of folate from baseline values in both study groups, as well as those of vitamins B6 and B12 and albumin, was observed. Significant between-group differences were detected in food preparation and in the individuals' ability to chew a variety of foods. This study suggests that implant overdentures do not have a more positive effect on the nutritional state of elderly edentate individuals at 6 and 12 mos post-treatment than new complete dentures. However, those wearing IODs are significantly more likely to take in their nutrients through fresh, whole fruits and vegetables.

Increased levels of homocysteine in patients with ulcerative colitis

AIM: To investigate serum levels of homocysteine (Hcys) and the risk that altered levels carry for thrombosis development in ulcerative colitis (UC) patients.

METHODS: 55 UC patients and 45 healthy adults were included. Hcys, vitamin B12 and folic acid levels were measured in both groups. Clinical history and thromboembolic events were investigated.

RESULTS: The average Hcys level in the UC patients was 13.3 ± 1.93 μmmol/L (range 4.60-87) and was higher than the average Hcys level of the control group which was 11.2 ± 3.58 μmmol/L (range 4.00-20.8) (P < 0.001). Vitamin B12 and folic acid average values were also lower in the UC group (P < 0.001). When multivariate regression analysis was performed, it was seen that folic acid deficiency was the only risk factor for hyperhomocysteinemia. Frequencies of thromboembolic complications were not statistically significantly different in UC and control groups. When those with and without a thrombosis history in the UC group were compared according to Hcys levels, it was seen that there were no statistically significant differences. A negative linear relationship was found between folic acid levels and Hcys.

CONCLUSION: We could not find any correlations between Hcys levels and history of prior thromboembolic events.

Uremic hyperhomocysteinemia: A randomized trial of folate treatment for the prevention of cardiovascular events

Homocysteine is a risk factor for atherosclerosis in the general population, and serum homocysteine levels are almost universally elevated in chronic renal failure patients. When such patients are treated with dialysis, cardiovascular disease accounts for more than 50% of their mortality, which, in some proportion, may be pathophysiologically related to the elevated serum homocysteine levels. From April 2003 to March 2005, we conducted a 2-year, double-blind, randomized, placebo-controlled trial of 186 patients with end-stage kidney disease due to any cause, who were older than 18 years and stable on hemodialysis. Patients were assigned to receive either oral folic acid 10 mg 3 times a week immediately after every dialysis session under nurse supervision or an identical-appearing placebo for the entire study. On admission, plasma total homocysteine (tHcy) levels were above 13.9 micromol/L in 96.7% of patients (median 25.0 micromol/L, range 9.3-104.0 micromol/L). In the placebo group, tHcy levels remained elevated at 6, 12, and 24 months, while oral folate significantly decreased tHcy to a median value of 10.5 (2.8-20.3) micromol/L, (p<0.01). During the study, 38 patients (folic acid group 17 vs. placebo group 21; p=0.47) died from cardiovascular disease. Kaplan-Meier life table analysis dealing with the incidence of cardiovascular events, both fatal and nonfatal (myocardial infarction, arrhythmias, angina, heart failure, cerebrovascular accident), showed that 2 years of folic acid treatment and the lowering of the homocysteine blood levels had no effect on cardiovascular events (p=0.41; hazard ratio 1.24, 95% CI 0.74-2.10). However, the carotid artery intima-media wall thickness measured in a blinded fashion decreased from 1.94 +/- 0.59 mm to 1.67 +/- 0.38 mm (p<0.01) after 2 years of folate therapy. In this short-term study of uremic patients, 2 years of folic acid supplementation normalized the tHcy blood levels in 92.3% of patients but did not change the incidence of cardiovascular events compared with the control group. However, ultrasonography of the common carotid arteries performed at entry and 24 months later showed a significant decrease in intima-media thickness with folate supplementation. This suggests that early folate supplementation may benefit patients with chronic renal failure by preventing cardiovascular deterioration.

Diet, nutrition and the prevention of hypertension and cardiovascular diseases

Cardiovascular diseases (CVD) are growing contributors to global disease burdens, with epidemics of CVD advancing across many regions of the world which are experiencing a rapid health transition. Diet and nutrition have been extensively investigated as risk factors for major cardiovascular diseases like coronary heart disease (CHD) and stroke and are also linked to other cardiovascular risk factors like diabetes, high blood pressure and obesity. The interpretation of evidence needs to involve a critical appraisal of methodological issues related to measurement of exposures, nature of outcome variables, types of research design and careful separation of cause, consequence and confounding as the basis for observed associations.

Adequate evidence is available, from studies conducted within and across populations, to link several nutrients, minerals, food groups and dietary patterns with an increased or decreased risk of CVD. Dietary fats associated with an increased risk of CHD include trans–fats and saturated fats, while polyunsaturated fats are known to be protective. Dietary sodium is associated with elevation of blood pressure, while dietary potassium lowers the risk of hypertension and stroke. Regular frequent intake of fruits and vegetables is protective against hypertension, CHD and stroke. Composite diets (such as DASH diets, Mediterranean diet, ‘prudent’ diet) have been demonstrated to reduce the risk of hypertension and CHD. Sufficient knowledge exists to recommend nutritional interventions, at both population and individual levels, to reduce cardiovascular risk. That knowledge should now be translated into policies which promote healthy diets and discourage unhealthy diets. This requires coordinated action at the level of governments, international organizations, civil society and responsible sections of the food industry.

The use of a Cissus quadrangularis formulation in the management of weight loss and metabolic syndrome

Aim

Once considered a problem of developed countries, obesity and obesity-related complications (such as metabolic syndrome) are rapidly spreading around the globe. The purpose of the present study was to investigate the use of a Cissus quadrangularis formulation in the management of metabolic syndrome, particularly weight loss and central obesity.

Methods

The study was a randomized, double-blind, placebo-controlled design involving 123 overweight and obese persons (47.2% male; 52.8% female; ages 19–50). The 92 obese (BMI >30) participants were randomized into three groups; placebo, formulation/no diet, and formulation/diet (2100–2200 calories/day). The 31 overweight participants (BMI = 25–29) formed a fourth (no diet) treatment group. All participants received two daily doses of the formulation or placebo and remained on a normal or calorie-controlled diet for 8 weeks.

Results

At the end of the trial period, statistically significant net reductions in weight and central obesity, as well as in fasting blood glucose, total cholesterol, LDL-cholesterol, triglycerides, and C-reactive protein were observed in participants who received the formulation, regardless of diet.

Conclusion

Cissus quadrangularis formulation appears to be useful in the management of weight loss and metabolic syndrome.

Elevated plasma homocysteine in obese schoolchildren with early atherosclerosis

Elevated plasma homocysteine is widely seen as an independent risk factor of cardiovascular disease in adults. In order to investigate the role of homocysteine in a paediatric population at risk for early atheroclerosis, we studied plasma homocysteine in obese schoolchildren and non-obese peers. Plasma homocysteine, serum vitamin B12 and serum folic acid were determined in 41 obese and 27 control subjects and related to carotid intima-media thickness and flow-mediated dilatation measured on high-resolution ultrasonography. Homocysteine, vitamin B12 and folic acid were all significantly elevated in obese children. In girls, plasma homocysteine correlated significantly with body mass index (r=0.56, p=0.002), increased ICA intima-media thickness (r=0.39, p=0.035) and flow-mediated dilatation (r=-0.40, p=0.031). In boys, none of these associations reached significance (all p>0.234). No independent association of homocysteine with IMT and FMD was seen after adjustment for BMI.

CONCLUSION

Plasma homocysteine is elevated in obese schoolchildren with hypertension and dyslipidaemia, particularly in girls. This may indicate a high-risk constellation, so that plasma homocysteine should be monitored in these children.

5,10-Methylenetetrahydrofolate reductase C677T gene polymorphism in Behcet's patients with or without ocular involvement

BACKGROUND

Increased serum levels of homocysteine (Hcy) have been reported in patients with Behçet's disease (BD) with an established risk factor for vascular involvement. Recently, the authors demonstrated that elevated Hcy levels are associated with ocular involvement in such patients. On the other hand, elevated levels of Hcy can result from genetic errors. Indeed, a mutation in the 5,10-methylenetetrahydrofolate reductase (MTHFR C677T) gene influences Hcy metabolism and, therefore, MTHFR C677T polymorphism provokes hyperhomocysteinaemia.

AIM

To investigate the possible genetic factor for the elevation of plasma Hcy level in patients with BD by examining gene interaction with the MTHFR C677T polymorphism, a crucial factor of the Hcy metabolism. In addition, the authors aimed to evaluate if there is an association between the C677T polymorphism and the presence of ocular involvement in such patients.

METHOD

A total of 59 patients with BD (25 men, 34 women) with a mean age of 34.9 years and 42 age and sex matched healthy control subjects (19 men, 23 women; mean age 32.2) were included in this investigation. MTHFR gene polymorphism was investigated by the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) of a genomic DNA fragment at nucleotide 677 in all subjects in both groups. The genetic equilibrium is assumed for the gene frequencies of the MTHFR polymorphism in both samples.

RESULTS

The genotype of the MTHFR gene differed between the Behçet's patients and control subjects (TT: 11.9 v 2.4%; CT: 55.9 v 61.9%; CC: 32.2 v 35.7 %). TT homozygous genotype was more frequently in BD patients than the controls, though the difference was not significant (p = 0.063). In BD patients with ocular involvement, however, the frequencies of MTHFR TT homogenetic type (27.8%) were significantly and statistically higher than those in BD patients without ocular involvement (4.9%, p = 0.022, odds ratio = 7.5), or the controls (2.4%, p = 0.003, odds ratio = 20.0). TT homozygous genotype was associated with an increased risk for ocular involvement.

CONCLUSION

Elevated serum levels of Hcy seem to be a result of C677T polymorphism of the MTHFR gene, with increased TT individuals over CC and CT genotype BD patients. Although no association was shown between the MTHFR reductase C677T polymorphism and the increased risk of oral aphtahe or genital ulcers, a mutation in this gene was associated with an increased risk of ocular involvement, suggesting genetic instability with a potential initiation of Hcy lowering therapy in this patient group.

Hyperhomocysteinemia in ulcerative colitis is related to folate levels

AIM: To study the prevalence and clinical significance of hyperhomocysteinemia (hHcys), an independent factor for arterial and venous thrombosis, in a group of patients with ulcerative colitis (UC).

METHODS: Fasting homocysteine (Hcys), folate, and vitamin B12 serum levels were measured in 40 UC patients and 50 healthy controls. Clinical data regarding UC were gathered.

RESULTS: Median serum Hcys levels in UC patients were similar to those in controls (12.26 µmol/L vs 12.32 µmol/L), but the prevalence of hHcys was higher in UC patients than in controls (30% vs 10%, P = 0.028). UC significantly increased the risk of hHcys (adjusted odds ratio: 4.125; 95%CI: 1.26-13.44). Multivariate regression analysis showed that male sex, folate and vitamin B12 deficiency or lower serum values were significant independent predictors of higher Hcys levels in UC patients (r² = 0.4; P<0.001).

CONCLUSION: hHcys is common in UC patients and it is related to folate and vitamin B12 deficiency or lower serum values. It would be reasonable for patients with UC to receive folate and vitamin B complex supplements as a prophylactic measure.

Dietary habits and nutritional biomarkers in Italian type 1 diabetes families: evidence of unhealthy diet and combined-vitamin-deficient intakes

OBJECTIVE

Nutritional status and lifestyle can have profound effects on health. To analyse behaviour patterns in population subgroups of public health importance, we compared lifestyle, dietary intake of energy and selected nutrients, and nutritional biomarkers of type 1 diabetes (T1DM) patients and nondiabetic first-degree relatives against control subjects with no family history of T1DM.

DESIGN

A cross-sectional study.

SETTING

Department of Internal Medicine, University of Pisa, Italy.

SUBJECTS

A total of 209 individuals including 38 type 1 patients, 76 relatives, and 95 healthy subjects.

INTERVENTIONS

We used the European Prospective Investigation of Cancer and Nutrition questionnaires to assess dietary intake and lifestyle. Anthropometric indices and nutritional biomarkers (such as plasma levels of albumin, iron, lipids, homocysteine, vitamin B9 and vitamin B12 as well as urinary outputs of nitrogen, sodium and potassium) were evaluated.

RESULTS

Emerging health issues: (1) In total, 45% of controls were overweight. Increasing age was associated with increasing body mass and decreasing activity in sport in front of an unchanged energy intake. (2) The distribution of energy sources was incorrect. The proportion of caloric intake derived from total fat and cholesterol did not match general guidelines. Total dietary fibre consumption was assessed to be adequate (25 g/day) in only 27% of all the participants. (3) Estimated daily intakes of water-soluble vitamin B9 and fat-soluble vitamin D and vitamin E were deficient in comparison with dietary reference intakes. (4) The prevalence of adoption and maintenance of healthful eating and physical activity habits was higher in women and T1DM patients (probably as a consequence of the medical educational intervention). On the contrary, supportiveness of the family in term of changing the undesirable behaviours at home seemed to fail.

CONCLUSIONS

This study provides first evidence indicating unhealthy dietary behaviours, which could even predispose to the development of diabetes and cardiovascular complications, in subjects living in Pisa. The combination of vitamin B9 and vitamin E deprivation could be deleterious for endothelial function, since these antioxidants have been implicated in the modulation of nitric oxide and eicosanoid signalling.

Increased plasma homocysteine concentrations accelerate cardiac allograft vasculopathy

BACKGROUND

A toxic and pro-oxidative effect of homocysteine on the coronary endothelium may accelerate cardiac allograft vascular disease (CAVD). In this study, we evaluated the influence of hyperhomocysteinemia on the course of CAVD.

METHODS

We investigated plasma homocysteine (tHCY) concentrations in 183 consecutive heart transplant recipients (158 men and 25 women, mean aged 53.1 +/- 10.0 years, at 6.7 +/- 3.2 years after transplantation) to evaluate the course of CAVD. We used serial coronary angiography to assess coronary status and graded the severity of CAVD based on the extent of luminal obstruction in the main coronary arteries (graded as 1-4). We defined progression as increased focal stenosis of >/=30% or as detection of a new coronary lesion after a mean observation period of 2.8 +/- 1.0 years. A multivariate analysis (backward logistic regression) was performed that included potential risk factors for CAVD. We excluded patients undergoing dialysis.

RESULTS

Initially, tHCY concentrations were increased in the entire cohort (mean, 18.6 +/- 7.6 mumol/liter) and ranged from 6.6 to 46.9 mumol/liter. A total of 105 patients (57.0%) had CAVD at first angiography, and progression was detected in 52 transplant recipients (28.0%). Patients with progressive CAVD had significantly greater tHCY concentrations (21.6 +/- 6.2 mumol/liter) at baseline investigation compared with patients who had stable courses (17.4 +/- 7.7 mumol/liter; p < 0.001). These results were independent of parameters such as sex, age, dyslipoproteinemia, cyclosporine blood concentrations, and indication for transplantation.

CONCLUSIONS

Progression of CAVD is strongly associated with increased tHCY concentrations. The intervals between routine surveillance angiography should be shortened in patients with hyperhomocysteinemia, and routine medical treatment to decrease homocysteine concentrations should be considered.

Folate therapy and in-stent restenosis after coronary stenting

BACKGROUND

Vitamin therapy to lower homocysteine levels has recently been recommended for the prevention of restenosis after coronary angioplasty. We tested the effect of a combination of folic acid, vitamin B6, and vitamin B12 (referred to as folate therapy) on the risk of angiographic restenosis after coronary-stent placement in a double-blind, multicenter trial.

METHODS

A total of 636 patients who had undergone successful coronary stenting were randomly assigned to receive 1 mg of folic acid, 5 mg of vitamin B6, and 1 mg of vitamin B12 intravenously, followed by daily oral doses of 1.2 mg of folic acid, 48 mg of vitamin B6, and 60 microg of vitamin B12 for six months, or to receive placebo. The angiographic end points (minimal luminal diameter, late loss, and restenosis rate) were assessed at six months by means of quantitative coronary angiography.

RESULTS

At follow-up, the mean (+/-SD) minimal luminal diameter was significantly smaller in the folate group than in the placebo group (1.59+/-0.62 mm vs. 1.74+/-0.64 mm, P=0.008), and the extent of late luminal loss was greater (0.90+/-0.55 mm vs. 0.76+/-0.58 mm, P=0.004). The restenosis rate was higher in the folate group than in the placebo group (34.5 percent vs. 26.5 percent, P=0.05), and a higher percentage of patients in the folate group required repeated target-vessel revascularization (15.8 percent vs. 10.6 percent, P=0.05). Folate therapy had adverse effects on the risk of restenosis in all subgroups except for women, patients with diabetes, and patients with markedly elevated homocysteine levels (15 micromol per liter or more) at baseline.

CONCLUSIONS

Contrary to previous findings, the administration of folate, vitamin B6, and vitamin B12 after coronary stenting may increase the risk of in-stent restenosis and the need for target-vessel revascularization.

Introduction to risk assessment and serum risk markers for the prevention of coronary heart disease and other potential conditions that impact men's health, part II: what do I tell my patients?

Markers and other potential tests for cardiovascular risk abound, and a more extensive review of these and other markers can be found elsewhere. Cardiovascular health tends to mirror urologic health for several conditions. It is imperative in the urology setting that clinicians discuss the probability of early morbidity and mortality with patients. This should not undermine the importance of prostate cancer and other diseases, but rather place risks in their proper perspective. Patients seem to need this guidance more than ever because life expectancy for most individuals continues to increase, and the potential for comorbidities seems to increase in the average aging patient. It is hoped that this article will prompt new interest in evaluating some risk factors for various urologic conditions. This may move researchers closer to discovering intervention agents that could impact numerous male health conditions favorably. Improving men's health will require a concerted educational and research effort from several health disciplines, a reminder that different medical specialties have much in common, and the role of preventive medicine is to point out similarities as opposed to differences.

Relation of homocysteine and C-reactive protein to urinary albumin loss

This study shows that elevated high-sensitivity C-reactive protein and plasma total homocysteine contribute independently to the likelihood of an increased urinary albumin:creatinine ratio. This result suggests that total homocysteine and C-reactive protein may be acting by separate mechanistic pathways.

Total plasma homocysteine and restenosis after percutaneous coronary angioplasty: current evidence

BACKGROUND

Restenosis after percutaneous coronary angioplasty (PTCA) remains an important limitation of this procedure.

AIM

To assess the relationship between homocysteine levels and restenosis after PTCA, and discuss the potential benefit of homocysteine-lowering therapy.

METHOD

MEDLINE-based literature review.

RESULTS

The conflicting literature on the association between homocysteine levels and restenosis after PTCA can partially be explained by differences in methodology. Depending on the type of studies considered, a pooling of data resulted in a 22%-36% risk reduction of restenosis in lesions exposed to low homocysteine levels. The strongest reduction was found in balloon-only treated lesions (42%), while only a trend (14%) was seen in stented lesions. Based on the only available trial, homocysteine-lowering therapy yielded a 54% restenosis rate reduction, 76% in balloon-only treated lesions and 31% in stented lesions. Furthermore, homocysteine-lowering therapy provided a significant clinical benefit with a 40% relative reduction in major adverse events at 6 months' follow-up.

CONCLUSIONS

This review suggests that plasma homocysteine is a modifiable risk factor for restenosis, which when lowered improves outcome after PTCA. This inexpensive treatment with virtually no side-effects could therefore be considered as adjunctive therapy for patients undergoing PTCA, while awaiting results from further studies.

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.

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.

Drugs affecting homocysteine metabolism: impact on cardiovascular risk

Elevated total plasma homocysteine has been established as an independent risk factor for thrombosis and cardiovascular disease. A strong relationship between plasma homocysteine levels and mortality has been reported in patients with angiographically confirmed coronary artery disease. Homocysteine is a thiol containing amino acid. It can be metabolised by different pathways, requiring various enzymes such as cystathionine beta-synthase and methylenetetrahydrofolate reductase. These reactions also require several co-factors such as vitamin B6 and folate. Medications may interfere with these pathways leading to an alteration of plasma homocysteine levels. Several drugs have been shown to effect homocysteine levels. Some drugs frequently used in patients at risk of cardiovascular disease, such as the fibric acid derivatives used in certain dyslipidaemias and metformin in type 2 (non-insulin-dependent) diabetes mellitus, also raise plasma homocysteine levels. This elevation poses a theoretical risk of negating some of the benefits of these drugs. The mechanisms by which drugs alter plasma homocysteine levels vary. Drugs such as cholestyramine and metformin interfere with vitamin absorption from the gut. Interference with folate and homocysteine metabolism by methotrexate, nicotinic acid (niacin) and fibric acid derivatives, may lead to increased plasma homocysteine levels. Treatment with folate or vitamins B6 and B12 lowers plasma homocysteine levels effectively and is relatively inexpensive. Although it still remains to be demonstrated that lowering plasma homocysteine levels reduces cardiovascular morbidity, surrogate markers for cardiovascular disease have been shown to improve with treatment of hyperhomocystenaemia. Would drugs like metformin, fibric acid derivatives and nicotinic acid be more effective in lowering cardiovascular morbidity and mortality, if the accompanying hyperhomocysteinaemia is treated? The purpose of this review is to highlight the importance of homocysteine as a risk factor, and examine the role and implications of drug induced modulation of homocysteine metabolism.

Relation of homocysteine, vitamin B(12), and folate to coronary in-stent restenosis

Coronary in-stent restenosis represents a clinical problem. Because homocysteine is being discussed as a new risk factor for atherosclerosis and thrombosis, this study investigated the relations of homocysteine, folate, and vitamin B(12) to the rate of in-stent restenosis. Patients undergoing successful percutaneous transluminal coronary angioplasty of native coronary lesions with stent implantation were investigated for fasting total serum homocysteine, folic acid, and vitamin B(12). The rate of in-stent restenosis was determined angiographically after 6 months, or earlier if clinically indicated. Of 292 enrolled patients, 262 (90%) (189 men and 73 women) underwent control angiography on an average of 6.3 +/- 1.0 (SD) months after intervention. The rate of in-stent restenosis was 36%. Univariate and multivariate analyses revealed no significant differences between patients with or without restenosis with regard to total homocysteine (median [interquartile range]: 12.9 [11.2 to 14.8] and 12.4 [10.3 to 15.4] micromol/L, respectively), folate (16.1 [12.4 to 20.5] and 15.4 [12.5 to 19.5] nmol/L, respectively), or vitamin B(12) (239.0 [182.5 to 322.1] and 258.4 [205.8 to 330.5] pmol/L, respectively). These results suggest that homocysteine, folate, and vitamin B(12) are not related to the angiographically determined rate of coronary in-stent restenosis after 6 months.

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.

Metabolism 2000: the emperor needs new clothes

Metabolism is one of the corner stones of nutritional science. As biology enters the post-genomic era and with functional genomics beginning to takeoff, we anticipate that the study of metabolism will play an increasingly important role in helping to link advances made via the reductionist paradigm, that has been so successful in molecular and cellular biology, with those emerging from observational studies in animals and human subjects. A reconstructive metabolically-focused approach offers a timely paradigm for enhancing the elegance of nutritional science. Here we give particular attention to the use of tracers as phenotyping tools and discuss the application of our metaprobe concepts with respect to some novel features of metabolism, including 'underground metabolism', 'metabolic hijacking', 'catalytic promiscuity' and 'moonlighting proteins'. The opportunities for enhancing the study of metabolism by new and emerging technologies, and the importance of the interdisciplinary research enterprise are also touched upon. We conclude that: (1) the metaprobe concepts and approach, discussed herein, potentially yield a quantitative physiological (metabolic) phenotype against which to elaborate partial or focused genotypes; (2) physiological (metabolic) phenotypes which have a whole-body or kinetically-discernible inter-organ tissue-directed metabolic signature are an ideal target for this directed tracer-based definition of the 'functional' genotype; (3) metabolism, probed with tracer tool kits suitable for measuring rates of turnover, change and conversion, becomes in the current sociology of the 'Net', like AOL, Yahoo. Alta Vista, Lycos or Ask Jeeves, the portal for an exploration of the metabolic characteristics of the 'Genomics Internet'.

Antioxidants and vitamins to reduce cardiovascular disease

Cardiovascular disease is the leading cause of morbidity and mortality in Western populations. Several lines of evidence support the role of oxidative stress in atherogenesis. Dietary micronutrients with antioxidant properties and vitamins have also been shown to have a benefit with regards to cardiovascular disease. The most persuasive evidence relates to alpha tocopherol and folate and vitamin B(12). Although the evidence is mounting for supplementation with alpha tocopherol and folate and B(12) for secondary prevention of cardiovascular disease, no clear consensus can be reached for primary prevention of cardiovascular disease. This will have to await results of ongoing clinical trials.