OBJECTIVE: To examine the effect of coenzyme Q10 supplementation on serum lipoprotein(a) in patients with acute coronary disease. STUDY DESIGN: Randomized double blind placebo controlled trial. SUBJECTS AND METHODS: Subjects with clinical diagnosis of acute myocardial infarction, unstable angina, angina pectoris (based on WHO criteria) with moderately raised lipoprotein(a) were randomized to either coenzyme Q10 as Q-Gel (60 mg twice daily) (coenzyme Q10 group, n=25) or placebo (placebo group, n=22) for a period of 28 days. RESULTS: Serum lipoprotein(a) showed significant reduction in the coenzyme Q10 group compared with the placebo group (31.0% vs 8.2% P<0.001) with a net reduction of 22.6% attributed to coenzyme Q10. HDL cholesterol showed a significant increase in the intervention group without affecting total cholesterol, LDL cholesterol, and blood glucose showed a significant reduction in the coenzyme Q10 group. Coenzyme Q10 supplementation was also associated with significant reductions in thiobarbituric acid reactive substances, malon/dialdehyde and diene conjugates, indicating an overall decrease in oxidative stress. CONCLUSION: Supplementation with hydrosoluble coenzyme Q10 (Q-Gel) decreases lipoprotein(a) concentration in patients with acute coronary disease.

The effects of oral treatment with coenzyme Q10 (120 mg/d) were compared for 28 days in 73 (intervention group A) and 71 (placebo group B) patients with acute myocardial infarction (AMI). After treatment, angina pectoris (9.5 vs. 28.1), total arrhythmias (9.5% vs. 25.3%), and poor left ventricular function (8.2% vs. 22.5%) were significantly (P < 0.05) reduced in the coenzyme Q group than placebo group. Total cardiac events, including cardiac deaths and nonfatal infarction, were also significantly reduced in the coenzyme Q10 group compared with the placebo group (15.0% vs. 30.9%, P < 0.02). The extent of cardiac disease, elevation in cardiac enzymes, and oxidative stress at entry to the study were comparable between the two groups. Lipid peroxides, diene conjugates, and malondialdehyde, which are indicators of oxidative stress, showed a greater reduction in the treatment group than in the placebo group. The antioxidants vitamin A, E, and C and beta-carotene, which were lower initially after AMI, increased more in the coenzyme Q10 group than in the placebo group. These findings suggest that coenzyme Q10 can provide rapid protective effects in patients with AMI if administered within 3 days of the onset of symptoms. More studies in a larger number of patients and long-term follow-up are needed to confirm our results.

It has been postulated that oxidatively modified low-density lipoprotein (LDL) contributes to the genesis of atherosclerosis. Ubiquinone has been suggested to be an important physiological lipid-soluble antioxidant and is found in LDL fractions in the blood. We measured plasma level of ubiquinone using high-performance liquid chromatography and plasma levels of total cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides in 245 normal subjects (186 males, 59 females) and in 104 patients (55 males, 49 females) who had coronary artery disease not receiving pravastatin and 29 patients (12 males, 17 females) receiving pravastatin. In the normal subjects, the plasma ubiquinone levels did not vary with age. In the patient groups, the plasma total cholesterol and LDL levels were higher and the plasma ubiquinone level lower than in the normal subject group. The LDL/ubiquinone ratio was higher in the patient groups. We found that ubiquinone level, either alone or when expressed in relation to LDL levels, was significantly lower in the patient groups compared with the normal subject group. The 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitor is thought to prevent atherosclerosis, however, it also inhibits ubiquinone production. The present study revealed that HMG CoA reductase inhibitor decreased plasma cholesterol level, and that it did not improve either the ubiquinone level or the LDL/ubiquinone ratio. From these results, the LDL/ubiquinone ratio is likely to be a risk factor for atherogenesis, and administration of ubiquinone to patients at risk might be needed.

The effects of coenzyme Q10 (CoQ10) on blood viscosity were studied in twelve patients (mean age 49 16 years) with ischemic heart disease. Twenty mg of CoQ10 was orally administered three times daily for two months (total dose 60 mg per day). Blood viscosity was measured with a cone-plate type viscometer at the shear rates of 37.5, 75, 150, and 375 s-1. Yield shear stress was calculated from Casson's plot. Blood viscosity decreased at each shear rate after the administration of CoQ10. Yield shear stress decreased significantly by the treatment with CoQ10. Hematocrit and fibrinogen were also measured, but showed no significant change. These results suggest that CoQ10 decreases the blood viscosity, i.e., improves the rheological properties of blood in ischemic heart disease.

Coenzyme Q10 (CoQ10) is indispensable in mitochondrial bioenergetics and for human life to exist. 88/115 patients completed a trial of therapy with CoQ10 for cardiomyopathy. Patients were selected on the basis of clinical criteria, X-rays, electrocardiograms, echocardiography, and coronary angiography. Responses were monitored by ejection fractions, cardiac output, and improvements in functional classifications (NYHA). Of the 88 patients 75%-85% showed statistically significant increases in two monitored cardiac parameters. Patients with the lowest ejection fractions (approx. 10%-30%) showed the highest increases (115 delta %-210 delta %) and those with higher ejection fractions (50%-80%) showed increases of approx. 10 delta %-25 delta % on therapy. By functional classification, 17/21 in class IV, 52/62 in class III, and 4/5 in class II improved to lower classes. Clinical responses appeared over variable times, and are presumably based on mechanisms of DNA-RNA-protein synthesis of apoenzymes which restore levels of CoQ10 enzymes in a deficiency state. 10/21 (48%) of patients in class IV, 26/62 (42%) in class III, and 2/5 (40%) in class II had exceptionally low control blood levels of CoQ10. Clinical responses on therapy with CoQ10 appear maximal with blood levels of approx. 2.5 micrograms< CoQ10/ml and higher during therapy.

J Am Coll Nutr 1998 Oct;17(5):435-41
Siri PW, Verhoef P, Kok FJ
Department of Food Technology and Nutrition Sciences, Wageningen Agricultural University, The Netherlands.

OBJECTIVES: To investigate the association of status of vitamins B6, B12 and folate with plasma fasting total homocysteine (tHcy) and with risk of coronary atherosclerosis; and to establish whether associations between vitamins and risk of coronary atherosclerosis are mediated by tHcy. METHODS: The study population consisted of 131 patients with angiography-defined severe coronary atherosclerosis and 88 referents with no or minor coronary stenosis. Previous analyses in this study population have shown that fasting tHcy is an independent risk factor for coronary atherosclerosis. In the present analyses, using multiple linear regression, we estimated differences in tHcy concentrations between subjects in the lowest and highest quartiles of concentrations of each of the vitamins, adjusting for age, gender, total:HDL cholesterol ratio, smoking habits, alcohol intake, blood pressure, serum creatinine, body mass index and the two other vitamins. We used logistic regression analysis conditional on the set of potential confounders described above to study the association between vitamin concentration and risk of coronary atherosclerosis. By comparing these estimated odds ratios (ORs) with those that were additionally adjusted for fasting tHcy, we determined whether the vitamins exerted their effects on disease risk via homocysteine metabolism. RESULTS: Cases who were in the upper quartile of serum vitamin B12 and erythrocyte folate concentrations showed statistically significantly lower tHcy concentrations (-4.00 and -4.71 mumol/L, respectively) than those in the lowest quartile. Referents in the upper quartile of plasma B6 showed significantly lower tHcy concentrations (-2.36 mumol/L) than referents in the lowest quartile. Subjects in the lowest quartile of vitamin B12 concentrations had higher risk of coronary atherosclerosis (OR: 2.91; 95% CI: 1.10, 7.71) compared to those in the highest quartile. The ORs and 95% CIs for low B6 and low folate were 0.86 (95% CI: 0.33, 2.22) and 0.58 (95% CI: 0.23, 1.48), respectively. Additional adjustment for fasting tHcy weakened
associations, although data indicated that low vitamin B12 concentration is a risk factor for coronary atherosclerosis, independently of tHcy. CONCLUSION: The presently accepted view that vitamin B6 mainly affects tHcy after methionine loading, and not fasting tHcy, is contradicted by our findings in referents. Low vitamin B12 concentrations were associated with an increased risk of coronary atherosclerosis, partly independently of tHcy. Although low folate status was a strong determinant of elevated tHcy concentrations, it was not associated with . increased risk of coronary atherosclerosis.

Am J Epidemiol 1996 May 1;143(9):845-59
Verhoef P, Stampfer MJ, Buring JE, Gaziano JM, Allen RH, Stabler SP,
Reynolds RD, Kok FJ, Hennekens CH, Willett WC
Department of Epidemiology and Public Health, Agricultural University, Wageningen, Netherlands.

Elevated plasma homocyst(e)ine levels are an independent risk factor for vascular disease. In a case-control study, the authors studied the associations of fasting plasma homocyst(e)ine and vitamins, which are important cofactors in homocysteine metabolism, with the risk of myocardial infarction. The cases were 130 Boston area patients hospitalized with a first myocardial infarction and 118 population controls, less than 76 years of age, enrolled in 1982 and 1983. Dietary intakes of vitamins B6, B12, and folate were estimated from a food frequency questionnaire. After adjusting for sex and age, the authors found that the geometric mean plasma homocyst(e)ine level was 11% higher in cases compared with controls (p = 0.006). There was no clear excess of cases with extremely elevated levels. The age- and sex-adjusted odds ratio for each 3-mumol/liter (approximately 1 standard deviation) increase in plasma homocyst(e)ine was 1.35 (95% confidence interval 1.05-1.75; p trend = 0/007). After further control for several risk factors, the odds ratio was not affected, but the confidence interval was wider and the p value for trend was less significant. Dietary and plasma levels of vitamin B6 and folate were lower in cases than in controls, and these vitamins were inversely associated with the risk of myocardial infarction, independently of other potential risk factors. Vitamin B12 showed no clear association with myocardial infarction, although methylmalonic acid levels were significantly higher in cases. Comparing the mean levels of several homocysteine metabolites among cases and controls, the authors found that impairment of remethylation of homocyst(e)ine (dependent of folate and vitamin B12 rather than on vitamin B6-dependent transsulfuration) was the predominant cause of high homocyst(e)ine levels in cases. Accordingly, plasma folate and, to a lesser extent, plasma vitamin B12, but not vitamin B6, correlated inversely with plasma homocyst(e)ine, even for concentrations at the high end of normal values. These data provide further evidence that plasma homocyst(e)ine is an independent risk factor for myocardial infarction. In this population, folate was the most important determinant of plasma homocyst(e)ine, even in subjects with apparently adequate nutritional status of this vitamin.

PURPOSE: Many epidemiologic studies have identified elevated plasma homocyst(e)ine as a risk factor for atherosclerosis and thromboembolic disease. To examine the relationship between vitamin intakes and plasma homocyst(e)ine, we analyzed dietary intake data from a case-control study of 322 middle-aged individuals with atherosclerosis in the carotid artery and 318 control subjects without evidence of this disease. METHODS: All of these individuals were selected from a probability sample of 15,800 men and women who participated in the Atherosclerosis Risk in Communities (ARIC) Study. RESULTS: Plasma homocyst(e)ine was inversely associated with intakes of folate, vitamin B6, and vitamin B12 (controls only for this vitamin)--the three key vitamins in homocyst(e)ine metabolism. Among nonusers of vitamin supplement products, on average each tertile increase in intake of these vitamins was associated with 0.4 to 0.7 mumol/L decrease in plasma homocyst(e)ine. An inverse association of plasma homocyst(e)ine was also found with thiamin, riboflavin, calcium, phosphorus, and iron. Methionine and protein intake did not show any significant association with plasma homocyst(e)ine. CONCLUSIONS: In almost all analyses, cases and controls showed similar associations between dietary variables and plasma homocyst(e)ine. Plasma homocyst(e)ine among users of vitamin supplement products was 1.5 mumol/L lower than that among nonusers. Further studies to examine possible causal relationships among vitamin intake, plasma homocyst(e)ine, and cardiovascular disease are needed.

J Am Coll Nutr 1996 Apr;15(2):136-43
Chasan-Taber L, Selhub J, Rosenberg IH, Malinow MR, Terry P, Tishler PV, Willett W, Hennekens CH, Stampfer MJ
Department of Epidemiology, Harvard School of Public Health, Boston,
Massachusetts, USA.

OBJECTIVE: To assess prospectively the risk of myocardial infarction (MI) associated with decreased plasma levels of folate and pyridoxal phosphate (PLP, a form of vitamin B6) in relation to elevated levels of total homocysteine (tHcy). DESIGN: Nested case-control study using prospectively collected blood samples. SETTING: Participants in the Physicians' Health Study. SUBJECTS: 14,916 male physicians, aged 40-84 years, with no prior MI or stroke provided plasma samples at baseline and were followed for 7.5 years. Samples from 333 men who subsequently developed MI, and their paired controls matched by age and smoking, were analyzed for folate and PLP levels. MEASURES OF OUTCOME: Acute MI or death due to coronary disease. RESULTS: In a model controlling for diabetes, angina, hypertension, Quetelet's index, and total/high-density lipoprotein cholesterol, men with the lowest 20% of folate levels (< 2.0 ng/mL) had a relative risk of 1.4 (95% confidence interval 0.9-2.3) compared with those in the top 80%. For the lowest 20% of vitamin B6 values, the relative risk was 1.5 (95% CI: 1.0-2.2). When we included both folate and B6 in a model with cardiovascular risk factors, the relative risk of MI for low as compared to high levels of folate was 1.3 (95% CI: 0.8-2.1) and for PLP, 1.3 (95% CI: 0.9-2.1). Adding tHcy to this model did not add significant predictive value (chi sq = 2.0, p > 0.05), except in the first half of the follow-up interval when men with the top 5% of tHcy values had an almost three-fold increase in risk of MI. CONCLUSIONS: Although not statistically significant, these prospective data are compatible with the hypothesis that low dietary intake of folate and/or vitamin B6 contribute to risk of MI.