Cholesterol reduction in cardiovascular disease. Clinical benefits and possible mechanisms

Atorvastatin Prevented and Reversed Dexamethasone-Induced Hypertension in the Rat

To assess the antioxidant effects of atorvastatin (atorva) on dexamethasone (dex)-induced hypertension, 60 male Sprague-Dawley rats were treated with atorva 30 mg/kg/day or tap water for 15 days. Dex increased systolic blood pressure (SBP) from 109 +/- 1.8 to 135 +/- 0.6 mmHg and plasma superoxide (5711 +/- 284.9 saline, 7931 +/- 392.8 U/ml dex, P < 0.001). In this prevention study, SBP in the atorva + dex group was increased from 115 +/- 0.4 to 124 +/- 1.5 mmHg, but this was significantly lower than in the dex-only group (P' < 0.05). Atorva reversed dex-induced hypertension (129 +/- 0.6 mmHg, vs. 135 +/- 0.6 mmHg P' < 0.05) and decreased plasma superoxide (7931 +/- 392.8 dex, 1187 +/- 441.2 atorva + dex, P < 0.0001). Plasma nitrate/nitrite (NOx) was decreased in dex-treated rats compared to saline-treated rats (11.2 +/- 1.08 microm, 15.3 +/- 1.17 microm, respectively, P < 0.05). Atorva affected neither plasma NOx nor thymus weight. Thus, atorvastatin prevented and reversed dexamethasone-induced hypertension in the rat.

Effect of statin adherence on cerebrovascular disease in primary prevention

BACKGROUND

Evidence from meta-analyses shows that statin therapy reduces all-cause mortality and nonhemorrhagic strokes. Nonadherence to statins may reduce this protective effect. The association between statin adherence and incidence of cerebrovascular disease remains unexplored outside the context of clinical trials.

OBJECTIVE

To evaluate the impact of statin adherence on the occurrence of cerebrovascular disease in a real clinical setting.

METHODS

A cohort of 112,092 patients was reconstructed using the Régie d'assurance maladie du Québec and Med-Echo databases. The Régie d'assurance maladie du Québec database contains information from 3 types of health-related data, such as demographic information, medical data, and the prescription claims file. The Med-Echo database contains data on acute care hospitalizations on all Quebec residents. All patients without cardiovascular disease aged 45-85 years who were newly treated with statins between 1999 and 2004 were eligible. A nested case-control design was used to study the occurrence of cerebrovascular disease. Adherence level was reported as a medication possession ratio. Conditional logistic regression models were used to estimate the rate ratio of cerebrovascular disease, adjusting for different covariables.

RESULTS

The mean patient age was 63 years; 49% had hypertension, 21% had diabetes, and 41% were males. Nonadherence was prevalent because only 55% of the patients were exposed to > or = 80% of the medication during follow-up. We did not observe any major differences, defined as more than 5%, between the groups, except for the sex, diabetes, and hypertension. High level of adherence to statins was associated with a reduction of cerebrovascular events (rate ratio: 0.74; 95% confidence interval, 0.65-0.84).

CONCLUSIONS

Our study suggests a relatively low level of adherence to statins, but more importantly, that adherence is associated with a risk reduction for cerebrovascular disease. Adherence to statin therapy needs to be improved, so that patients can benefit from the full protective effects of statin therapy.

Acute effect of nut consumption on plasma total polyphenols, antioxidant capacity and lipid peroxidation

BACKGROUND

Nuts have been shown to have beneficial effects on human health due to the healthy fat content; however, the effect of antioxidants (i.e. polyphenols) in nuts have not been fully investigated. The present study aimed to assess the immediate effect of a polyphenol-rich meal (75% of energy from nuts: walnuts or almonds) and a polyphenol-free meal on plasma polyphenol content, antioxidant capacity and lipid peroxidation in healthy volunteers.

METHODS

Thirteen subjects participated in a randomized, crossover, intervention study. After an overnight fast, walnuts, almonds or a control meal in the form of smoothies were consumed by study subjects. Each subject participated on three occasions, 1 week apart, consuming one of the smoothies each time. Blood samples were obtained at fasting and then at intervals up to 3.5 h after consumption of the smoothies.

RESULTS

There was a significant increase in plasma polyphenol concentration following both nut meals, with peak concentrations being achieved at 90 min, and with a walnut meal having a more sustained higher concentration than an almond meal. The plasma total antioxidant capacity reached its highest point at 150 min postconsumption of the nut meals, and was higher after the almond compared to walnut meal. A gradual significant (P < 0.05) reduction in the susceptibility of plasma to lipid peroxidation was observed 90 min after ingestion of the nut meals. No changes were observed following consumption of control meal.

CONCLUSIONS

Consumption of both nuts increased plasma polyphenol concentrations, increased the total antioxidant capacity and reduced plasma lipid peroxidation.

Endothelial function in the time of the giants

Paul Vanhoutte is one of the fathers of vascular biology. Among his great contributions, he demonstrated that endothelium modulates vasomotor response to vasoactive products (including serotonin) that are released when platelets aggregate in an artery. He found in arteries ex vivo that when endothelium is dysfunctional, in atherosclerosis or hypertension, normal relaxation to aggregation of platelets is impaired and vessels may contract. He proposed that this mechanism may predispose to vasospasm. The results of our experiments in vivo indicate that atherosclerosis greatly potentiates vasoconstrictor responses to serotonin in the limb, brain, and eye of monkeys. We proposed that transient ischemic attacks may be mediated by platelet-induced vasospasm. We observed endothelial dysfunction in atherosclerotic monkeys, with improvement of endothelial function when hypercholesterolemia was corrected. Recently, we studied the aortic valve, which has unique endothelium, in hypercholesterolemic mice to examine the pathophysiology of aortic valvular stenosis. Oxidative stress is increased in stenotic valves, and severe aortic stenosis develops in about one third of old, hypercholesterolemic mice. In stenotic aortic valves from humans, there is increased oxidative stress near calcified regions of the valves. Oxidative stress may trigger expression of pro-calcific genes in the aortic valve. Finally, we have used gene transfer of extracellular superoxide dismutase (ecSOD) to study endothelial effects of oxidative stress. Gene transfer of normal ecSOD improves endothelial dysfunction in several disease states, but gene transfer of ecSOD(R213G), a gene variant of ecSOD that is common in humans, fails to improve endothelial function. Gene transfer approaches may be useful to study mechanisms by which gene variants predispose to endothelial dysfunction and vascular disease.

Evaluation of endothelial function in hypertensive elderly patients by high-resolution ultrasonography

BACKGROUND

Multiple investigations, both in experimental models and in middle-aged patients with essential hypertension, demonstrate impaired endothelium-dependent vasodilatation.

HYPOTHESIS

We attempted to determine whether hypertension still exerts additional negative effect on endothelial function of large arteries in hypertensive elderly patients who may already be affected by endothelial dysfunction due to aging.

METHODS

We compared 13 elderly patients with hypertension [69 +/- 9 years, (mean +/- standard deviation)] with 13 matched healthy elderly subjects (72 +/- 6 years) as controls. Using high-resolution vascular ultrasound, we measured brachial artery responses to reactive hyperemia (with increased flow causing endothelium-dependent dilatation) and sublingual nitroglycerin (causing endothelium-independent dilatation).

RESULTS

Flow-mediated dilatation correlated inversely with age (r = -0.60, p = 0.03) in the controls. Flow-mediated dilatation was significantly impaired in hypertensive elderly patients (6.7 +/- 3.3 vs. 13.3 +/- 1.8% in controls, p < 0.0001). No significant difference could found in nitroglycerin-induced dilatation between controls (12.1 +/- 4.9%) and hypertensive elderly patients (10.2 +/- 6.8%, p = 0.5). On multivariate analysis, flow-mediated dilatation in hypertensive elderly patients was inversely related to aging (r = -0.37, p = 0.04) and mean blood pressure (r = -0.57, p = 0.03).

CONCLUSIONS

Our study showed decreased flow-mediated dilatation with aging even in the healthy controls, and further decline in flow-mediated dilatation in hypertensive elderly patients compared with controls. This impairment of flow-mediated dilatation in hypertensive elderly patients was related to age and mean blood pressure, indicating that aging and hypertension may independently impair endothelial function in the brachial artery of these patients.

Coronary risk factors, endothelial function, and atherosclerosis: a review

The traditional risk factors for coronary heart disease, which include hypercholesterolemia, hypertension, cigarette smoking, diabetes mellitus, and high-fat diet, have all been associated with impairments in endothelial function. Impaired endothelium function may promote the development of atherosclerosis through its effects on vasoregulation, platelet and monocyte adhesion, vascular smooth muscle cell growth, and coagulation. Increased oxidative stress may be another mechanism by which endothelial dysfunction contributes to atherosclerosis, although controversy exists on this issue. Risk factor modification, particularly lowering elevated concentrations of low-density lipoprotein cholesterol, improves endothelial function. At least seven clinical studies have demonstrated improved endothelial function with cholesterol reductions in patients with markedly elevated or even borderline elevations in cholesterol concentrations, whether or not coronary heart disease is present. Other interventions that improve endothelial function include blood pressure reduction, smoking cessation, and administration of estrogen to postmenopausal women.

Long-term efficacy and safety of cerivastatin 0.8 mg in patients with primary hypercholesterolemia

BACKGROUND

Statins are the agents of choice in reducing elevated plasma low-density lipoprotein cholesterol (LDL-C).

HYPOTHESIS

Cerivastatin 0.8 mg has greater long-term efficacy in reducing LDL-C than pravastatin 40 mg in primary hypercholesterolemia.

METHODS

In this double-blind, parallel-group, 52-week study, patients (n = 1,170) were randomized (4:1:1) to cerivastatin 0.8 mg, cerivastatin 0.4 mg, or placebo daily. After 8 weeks, placebo was switched to pravastatin 40 mg. Patients with insufficient LDL-C lowering after 24 weeks were allowed open-labeled resin therapy.

RESULTS

Cerivastatin 0.8 mg reduced LDL-C versus cerivastatin 0.4 mg (40.8 vs. 33.6%, p <0.0001) or pravastatin 40 mg (31.5%, p<0.0001), and brought 81.8% of all patients, and 54.1% of patients with atherosclerotic disease, to National Cholesterol Education Program (NCEP) goals. Cerivastatin 0.8 mg improved mean total C (-29.0%), triglycerides (-18.3%), and high-density lipoprotein cholesterol (HDL-C) (+9.7%) (all p < or = 0.013 vs. pravastatin 40 mg). Higher baseline triglycerides were associated with greater reductions in triglycerides and elevations in HDL-C with cerivastatin. Cerivastatin was well tolerated; the most commonly reported adverse events were arthralgia, headache, pharyngitis, and rhinitis. Symptomatic creatine kinase > 10x the upper limit of normal (ULN) occurred in 1, 1.5, and 0% of patients receiving cerivastatin 0.8 mg, cerivastatin 0.4 mg, and pravastatin 40 mg, respectively. Repeat hepatic transaminases >3 x ULN occurred in 0.3-0.5, 0.5, and 0% of patients, respectively.

CONCLUSION

In long-term use, cerivastatin 0.8 mg effectively and safely brings the majority of patients to NCEP goal.

Cardioprotective effects of pitavastatin on cardiac performance and remodeling in failing rat hearts

BACKGROUND

Activation of phosphatidylinositol 3-kinase (PI3K)-Akt signaling by statins increases the activity of endothelial nitric oxide synthase (eNOS). We investigate whether statins (pitavastatin) improve cardiac function and remodeling via eNOS production associated with the PI3K-Akt signaling pathway, Rho-kinase (ROCK) pathway, and the development of oxidative stress in Dahl salt-sensitive (DS) hypertensive rats with heart failure (DSHF).

METHODS

Pitavastatin (3 mg/kg per day), or pitavastatin plus specific PI3K inhibitor, wortmannin (1 mg/kg per day), or wortmannin alone were administered from the age of 11-18 weeks. Age-matched male Dahl salt-resistant (DR) rats served as a control group.

RESULTS

Decreased end-systolic elastance (Ees) and percent fractional shortening (%FS) in failing rats was significantly ameliorated by pitavastatin, but not pitavastatin plus wortmannin or wortmannin alone. Upregulation of eNOS and Akt phosphorylation by pitavastatin was suppressed by pitavastatin plus wortmannin or wortmannin alone. Pitavastatin effectively inhibited the vascular lesion formation such as medial thickness and perivascular fibrosis, but not pitavastatin plus wortmannin or wortmannin alone. Activated RhoA and myosin light chain phosphorylation and RhoA, ROCK expression was inhibited by pitavastatin or a specific ROCK inhibitor, Y-27632, and downregulated eNOS expression and Akt phosphorylation was ameliorated by Y-27632. Increased expression of NAD(P)H oxidase subunits and activated p65 nuclear factor (NF)-kappaB, p44/p42 extracellular signal-regulated kinases and its downstream effector p90 ribosomal S6 kinase phosphorylation in failing rat hearts was inhibited by pitavastatin.

CONCLUSIONS

These findings suggest that pitavastatin may improve cardiac function and remodeling via eNOS production associated with the PI3K-Akt signaling pathway, the ROCK pathway and oxidative stress.

Influence of menopause on biochemical markers of endothelial dysfunction-A case-control pilot study in North Indian population

OBJECTIVE

Menopause, an estrogen deficient state, is known to increase the cardiovascular risk. Lipid changes accompanying menopause account for only few cases of coronary artery disease (CAD). Endothelium-dependent nitric oxide-mediated vasodilatory mechanisms are also known to play a role in development of coronary artery disease, but studies in menopausal women are very few. This study was hence undertaken to see if nitric oxide (NO)-cyclic guanidine monophosphate (c-GMP) pathway is influenced by menopause.

DESIGN

This study was a hospital-based case-control study involving 100 women in age group 40-55 years. Of these, 50 women were postmenopausal and 50 were premenopausal. Women with known risk factors for CAD were excluded. Fasting blood samples from these women were collected and analyzed for estradiol levels, lipid profile, apolipoprotein B, plasma nitric oxide, c-GMP and platelet nitric oxide using standard kits and reagents. Statistical analysis was done on SPSS and two-tailed p-value <0.05 was considered significant.

RESULT

Postmenopausal women had significantly lower estradiol, plasma NO, and c-GMP levels as compared to premenopausal women (p<0.05). Cholesterol, low-density lipoprotein (LDL) cholesterol and apolipoprotein B (apo-B) levels were higher and HDL levels were lower in postmenopausal as compared to premenopausal women (p<0.05). Plasma NO showed a significant positive correlation with estradiol, HDL levels and negative correlation with apo-B levels.

CONCLUSION

Menopause tends to downregulate NO-c-GMP pathway resulting in endothelial dysfunction. The mechanism may be directly through estrogen receptors or indirectly through potentiation of dyslipidemia.

Hypocholesterolemic effect of stilbenes containing extract-fraction from Cajanus cajan L. on diet-induced hypercholesterolemia in mice

Cajanus cajan (L) is a natural plant which contains a lot of potential active components. In the present study, we identified the effects of the stilbenes containing extract-fraction from Cajanus cajan L (sECC) on diet-induced (for 4 weeks) hypercholesterolemia in Kunming mice. All experimental mice were divided into 5 groups: control group, model group, sECC-treated with 200 or 100 mg/kg/day, and simvastatin group. The effects of sECC were investigated by monitoring serum and liver lipid profile (cholesterol homeostasis and triglyceride) as well as serum superoxide dismutase activity in those mice. To further explore the mechanism of sECC, hepatic 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA reductase), cholesterol 7α-hydroxylase (CYP7A1), and low density lipoprotein receptor (LDL receptor) expressions in cholesterol homeostasis were analyzed by reverse transcription PCR. After 4 weeks pretreatment, compared with model group, the increased serum and hepatic total cholesterol were markedly attenuated by sECC (200 mg/kg) by 31.4% and 22.7% (p<0.01), respectively, the triglyceride levels of serum and liver were also lowered by 22.98% and 14.39%, respectively. At the same time, serum LDL cholesterol decreased by 52.8% (p<0.01) accompanied with the activities of serum superoxide dismutase increased by 20.98%. Atherogenic index and body weight were also reduced markedly. The mRNA expressions of HMG-CoA reductase, CYP7A1, and LDL-receptor were significantly enhanced in the mice administered with sECC (200 mg/kg/day), whereas those expressions were suppressed by the hypercholesterolemic diet. These data indicate that sECC reduces the atherogenic properties of dietary cholesterol in mice. Its hypocholesterolemic effect may involve enhancement of the hepatic LDL-receptor and cholesterol 7alpha-hydroxylase expression levels and bile acid synthesis.

Recent developments in the treatment of atherosclerosis

Atherosclerosis is one of the most frequent causes of cardiac arrest. The major cause of this disease is high concentrations of lipid in the blood. Medicinal agents so far have been quite successful in the management of hyperlipidemia. Among the several widely used drugs, (fibrates, statins and niacin) statins are the most frequently prescribed in many forms of hyperlipidemia. Recently, statins have been found to produce serious toxicities, which are rare but can be potentially harmful and are noise concern for the immediate need to develop some new chemical entities in this category. This review is primarily concerned with recent developments in atherosclerotic drug discovery including novel inhibitors of cholesterol biosynthesis, cholesterol absorption inhibitors and antioxidants. The review also focuses on possible future targets including gene therapy.

Observational studies of statins in heart failure with preserved systolic function

This article reviews the available evidence from observational studies concerning the effect of statin therapy in patients who have heart failure and a preserved ejection fraction (diastolic heart failure). Observational studies suggest that statin therapy is associated with lower mortality in patients who have diastolic heart failure. These results emphasize the need for a randomized study of the effect of statins in diastolic heart failure. Until the results of such studies are available, it is recommended to use statins in patients with diastolic heart failure who otherwise have an indication for statin therapy.

Endothelin-1, aging and hypertension

PURPOSE OF REVIEW

Endothelin-1 system activation plays an important role in the etiology of atherosclerotic vascular disease. Aging and hypertension are two independent cardiovascular risk factors that have been shown to exhibit increased endothelin-1 system activation. This review focuses on the cardiovascular effects of the endothelin system, its relation to aging and hypertension, as well as potential treatment options.

RECENT FINDINGS

Many of the cardiovascular complications associated with both aging and hypertension are attributable, in part, to endothelial dysfunction, particularly vasomotor dysregulation. To date most studies have focused on the effects of aging and hypertension on endothelium-dependent nitric oxide-mediated vasodilation. However, endothelin-1-mediated vasoconstrictor tone increases with age and contributes to the pathogenesis of hypertension. Pharmacologic approaches to reduce endothelin-1 system activation have produced limited results and are largely disease-specific. In contrast, regular aerobic exercise has been shown to be extremely effective at reducing endothelin-1 system activity.

SUMMARY

Both aging and hypertension represent important cardiovascular disease risk factors that are characterized by increased endothelin-1-mediated vasoconstrictor tone. Future studies are needed to elucidate pharmacologic options for reducing endothelin-1 system activity especially in older hypertensive adults, though regular aerobic exercise must continue to be a point of emphasis for maintaining/improving vascular health.

Placing COURAGE in context: review of the recent literature on managing stable coronary artery disease

Coronary artery disease (CAD) is the leading cause of death in the United States, but prevention and intervention efforts are lowering mortality. This progress is being undercut by rising rates of obesity and diabetes, and adherence to evidence-based prevention efforts is less than ideal. Many patients with CAD who are asymptomatic or have minimal symptoms undergo percutaneous coronary intervention (PCI) each year, even though PCI has not been demonstrated to improve survival for this group. Motivated by the recent controversy surrounding the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial, we reviewed randomized clinical trials with follow-up published in the past decade comparing medical management with revascularization for stable CAD to provide a context for the COURAGE trial. We searched for relevant studies published from January 1, 1997, until the date of electronic publication of the COURAGE study results, March 26, 2007; references cited in the COURAGE publication were also reviewed. Evidence shows that PCI does not decrease mortality or risk of myocardial infarction over optimal medical or lifestyle therapy in patients with chronic stable CAD. In published studies, early benefits in angina control afforded by revascularization wane over time; this could change with modern interventional therapies. The final word is not that medical therapy is superior for all patients, but that optimizing medical and lifestyle therapy is appropriate as an initial management strategy for most patients who do not have unstable or disabling symptoms. It is essential that systems are set in place to make the medical management of patients with CAD second nature; this focus could be one of the most powerful results of the COURAGE trial.

Low HDL cholesterol is a risk factor for deficit and decline in memory in midlife: the Whitehall II study

OBJECTIVE

The purpose of this study was to examine the relationship between fasting serum lipids and short-term verbal memory in middle-aged adults.

METHODS AND RESULTS

Total cholesterol, high-density lipoprotein cholesterol (HDL-C), triglycerides, and memory were measured twice, at mean ages 55 and 61, in 3673 male and female participants of the Whitehall II study. Short-term verbal memory was assessed using a 20-word list. Logistic regression was used to model associations between ATP-III categories of lipids and memory deficit (recall of < or =4 words) and decline (decrease of > or =2 words). Analyses were adjusted for education, occupational position, coronary heart disease, stroke, hypertension, use of medication, diabetes, smoking, and alcohol consumption. Compared to high HDL-C (> or =60 mg/dL), low HDL-C (<40 mg/dL) was associated with greater odds of memory deficit at the first (OR=1.27; 95% confidence interval [CI]=0.91 to 1.77) and second wave of this study (OR=1.53; 95% CI=1.04 to 2.25) in fully adjusted analysis. Decrease in HDL-C over the 5-year follow-up period was associated with decline in memory in the adjusted analysis (OR=1.61; 95% CI=1.19 to 2.16); no interaction with APOE e4 status was present.

CONCLUSIONS

HDL-C levels are potentially modifiable, and our results suggest that low HDL-C is associated with poor memory and decline in memory in middle-aged adults.

Comparison of hypolipidemic activity of synthetic gallic acid-linoleic acid ester with mixture of gallic acid and linoleic acid, gallic acid, and linoleic acid on high-fat diet induced obesity in C57BL/6 Cr Slc mice

Hyperlipidemia is the major risk factors of heart disease such as atherosclerosis, stroke, and death. In the present study, we studied the effect of gallic acid (GA), linoleic acid (LA), mixture of GA and LA (MGL), and chemically synthesized gallic acid-linoleic acid ester (octadeca-9,12-dienyl-3,4,5-trihydroxybenzoate, GLE) on the ability to ameliorate hyperlipidemia in C57BL/6 mice fed a high-fat diet (HFD). GLE, GA, LA, and MGL were mixed with HFD and the composition of the test compounds were 1% of the diet for 7 weeks. After 7 weeks, the average body weight of ND and GLE groups was lower than that of HFD group (P<0.05). The liver weight of mice decreased (P<0.05) in all treatment groups relative to HFD fed group. The plasma lipids such as triglyceride and LDL-cholesterol were found to be decreased (P<0.05) in GLE, GA, LA, and MGL fed mice when compared to that of HFD fed mice. But high-density lipoprotein (HDL) cholesterol increased (P<0.05) in HFD and GLE fed mice when compared to that of ND fed mice. The hepatic accumulation of fat droplets of GA, LA, GLE, and MGL group showed considerably lower than that of HFD group. Adipose histology showed that GLE supplementation was found to be more effective in decreasing the size of adipocyte relative to those of other treatment groups. In conclusion, the supplementation of synthetic GLE from gallic acid and linoleic acid ester may have a potential hypolipidemic effect on mice fed high-fat diet. Further studies are required to prove GLE as a hypolipidemic agent.

The effect of hypercholestrolemia on calf muscle hemoglobin oxygen saturation in patients with intermittent claudication

The purpose was to compare calf muscle hemoglobin oxygen saturation and exercise performance in hypercholesterolemic and normocholesterolemic patients with peripheral arterial disease. Hypercholesterolemic and normocholesterolemic patients had similar ankle/ brachial index (0.72 +/- 0.24 vs 0.79 +/- 0.28, [mean +/- SD]; P = .334). Hypercholesterolemic patients had shorter initial claudication distance (214 +/- 168 m vs 331 +/- 185 m, P = .026), absolute claudication distance (391 +/- 219 m vs 549 +/- 211 m, P = .035), and lower calf muscle hemoglobin oxygen saturation at the occurrence of initial claudication distance (27 +/- 21% vs 39 +/- 20%; P = .013), and absolute claudication distance (26 +/- 21% vs 36 +/- 21%; P = .021). Hypercholesterolemia is associated with shorter walking distances and calf muscle hemoglobin oxygen saturation during exercise in patients limited by intermittent claudication.

Corn fiber oil and sitostanol decrease cholesterol absorption independently of intestinal sterol transporters in hamsters

OBJECTIVE

The aim of this study was to investigate the cholesterol-lowering mechanisms of corn fiber oil (CFO), ferulate phytostanyl esters (FPEs) and parent compounds of FPE, including sitostanol and ferulic acid, in hamsters.

METHOD

Seventy male Golden Syrian hamsters were randomly assigned to six experimental diets for 4 weeks: (1) cornstarch-casein-sucrose-based control diet (control); and (2) control diet plus 0.1% (wt/wt) cholesterol (cholesterol-control). The remaining four groups were given cholesterol-control diet with: (3) 10% (wt/wt) CFO; (4) 0.5% (wt/wt) sitostanol; (5) 0.23% (wt/wt) ferulic acid; and (6) 0.73% (wt/wt) FPE. At the end of dietary intervention, total plasma cholesterol, high-density lipoprotein cholesterol and triglyceride concentrations were determined. Parameters of cholesterol kinetics, including cholesterol absorption and synthesis, as well as mRNA expression of sterol transporters such as Niemann-Pick C1 like 1 (NPC1L1), ATP-binding cassette G5 (ABCG5) and ABCG8, were assessed.

RESULTS

Supplementation with CFO decreased (P<.0001) plasma total cholesterol levels by 29% as compared with the cholesterol-control group, while FPE and sitostanol reduced (P<.02) cholesterolemia by 15% and 14%, respectively. CFO and sitostanol decreased (P<.05) cholesterol absorption by 24% compared to the cholesterol-control group. Dietary intervention did not alter the intestinal gene expression of ABCG5, ABCG8 and NPC1L1.

CONCLUSION

The present results show that the CFO-induced and sitostanol-induced decrease in cholesterol absorption is independent of intestinal enterocyte sterol transporters such as ABCG5, ABCG8 and NPC1L1 in hamsters.

Achieving lipid goals with rosuvastatin compared with simvastatin in high risk patients in real clinical practice: a randomized, open-label, parallel-group, multi-center study: the DISCOVERY-Beta study

The aim of this multi-center, open-label, randomized, parallel-group trial was to compare the efficacy of rosuvastatin with that of simvastatin in achieving the 1998 European Atherosclerosis Society (EAS) lipid treatment goals. 504 patients (> or =18 years) with primary hypercholesterolemia and a 10-year cardiovascular (CV) risk >20% or history of coronary heart disease (CHD) or other established atherosclerotic disease were randomized in a 2:1 ratio to receive rosuvastatin 10 mg or simvastatin 20 mg once daily for 12 weeks. A significantly higher proportion of patients achieved 1998 EAS low-density lipoprotein cholesterol (LDL-C) goal after 12 weeks of treatment with rosuvastatin 10 mg compared to simvastatin 20 mg (64 vs 51.5%, p < 0.01). Similarly, significantly more patients achieved the 1998 EAS total cholesterol (TC) goal and the 2003 EAS LDL-C and TC goals (p < 0.001) with rosuvastatin 10 mg compared with simvastatin 20 mg. The incidence of adverse events and the proportion of patients who discontinued study treatment were similar between treatment groups. In conclusion, in the DISCOVERY-Beta Study in patients with primary hypercholesterolemia greater proportion of patients in the rosuvastatin 10 mg group achieved the EAS LDL-C treatment goal compared with the simvastatin 20 mg group. Drug tolerability was similar across both treatment groups.

Hypolipidemic effect of Telfairia occidentalis (fluted pumpkin) in rats fed a cholesterol-rich diet

Telfairia occidentalis (fluted pumpkin) is one of the commonly consumed leafy vegetables in Nigeria. In order to justify its inclusion in herbal preparations in African traditional medicine, the possible hypolipidemic effect of this vegetable was investigated in rats fed a cholesterol-rich diet. The ability of Questran, a hypolipidemic drug, to attenuate hypercholesterolemia was also examined. Rats were fed with either a basal diet containing cholic acid (0.2%) or a supplemented diet with T. occidentalis at the 3% and 6% levels. Oral administration of cholesterol for 9 consecutive weeks resulted in a significant increase (P < .001) in the relative weight of the heart of cholesterol-fed rats. However, supplemented diets significantly (P < .001) ameliorated the cholesterol-induced enlargement of the heart. Rats fed on supplemented diets had a dose-dependent reduction in plasma and postmitochondrial supernatant fraction (PMF) cholesterol levels. In particular, supplemented diets containing 3% and 6% T. occidentalis decreased plasma and PMF cholesterol levels by 20% and 30% and by 30% and 45%, respectively. A similar decrease in plasma and PMF cholesterol levels was obtained in Questran-treated hypercholesterolemic rats. Furthermore, 3% and 6% T. occidentalis-supplemented diets significantly (P < .05) decreased the cholesterol-induced increase in plasma and PMF low-density lipoprotein (LDL) cholesterol levels by 24% and 48% and by 28% and 52%, respectively. In contrast, there was no significant difference (P > .05) in plasma and PMF triglyceride levels of rats fed on supplemented diets when compared with cholesterol-fed rats. There were significant decreases (P < .05) in lipid peroxidation levels in rats fed on the supplemented diets. Specifically, 3% and 6% T. occidentalis-supplemented diets decreased plasma and PMF lipid peroxidation by 24% and 20% and by 42% and 21%, respectively. This study demonstrates that T. occidentalis may be a useful therapy for hypercholesterolemia through reducing oxidative stress and cholesterol levels.

Statin therapy is associated with improved outcomes in vascular surgery patients with renal impairment

BACKGROUND

Little is known about the association between baseline kidney function, statin therapy, and outcome after vascular surgery in patients with and without chronic kidney disease.

METHODS

A total of 2126 patients underwent elective major vascular surgery and were divided into 2 categories based on baseline creatinine clearance (CrCl), calculated using the Cockcroft-Gault equation: CrCl > or = 60 mL/min (n = 1358, reference) and CrCl < 60 mL/min (n = 768). Outcome measures were 30-day and long-term all-cause, cardiac, and cerebrocardiovascular mortality. Mean follow-up was 6.0 +/- 3.7 years. Multivariate Cox regression analysis, including potential confounders and propensity score for statin use, was applied. Data are presented as hazard ratios (HRs) with 95% CI.

RESULTS

Thirty-day all-cause, cardiac, and cerebrocardiovascular mortality rates were 3.8% versus 10.2%, 1.3% versus 4.2%, and 2.7% versus 7.8%, respectively, according to the 2 categories of kidney function. In addition, long-term all-cause, cardiac, and cerebrocardiovascular mortality rates were 46.6% versus 72.5%, 14.6% versus 26.4%, and 23.0% versus 40.6%, respectively. Statin therapy was associated with an overall significant improved 30-day and long-term all-cause mortality, independent of other important confounders. However, in patients with a CrCl > or = 60 mL/min, the long-term cardiac and cerebrocardiovascular beneficial effects did not reach statistical significance (HR 0.93, 95% CI 0.61-1.41 and HR 0.89, 95% CI 0.63-1.24, respectively) when compared with patients with a CrCl of < 60 mL/min (HR 0.63, 95% CI 0.41-0.96 and HR 0.67, 95% CI 0.48-0.94, respectively).

CONCLUSIONS

The level of kidney function is an independent predictor of short- and long-term outcome after major noncardiac surgery. In addition, perioperative statin use in patients with kidney disease is associated with a reduction in the short- and long-term all-cause, cardiac, and cerebrocardiovascular mortality.

Beyond lipid lowering: the anti-hypertensive role of statins

INTRODUCTION

The management of the hypercholesterolemic patient has evolved tremendously with the introduction of the HMG-CoA Reductase inhibitors, a class of drugs better known as the statins. Statins modify cholesterol metabolism by inhibiting the rate-limiting enzyme of cholesterol biosynthesis, producing greater decreases in plasma cholesterol levels than previously realized with hypolipidemic therapy. With the advent of the classic statin-megatrials such as the Scandinavian Simvastatin Survival Study (4S), WOSCOPS, CARE, and the more recent Heart Protection Study (HPS), the role of statins in both the primary and secondary prevention and ultimate risk reduction of patients with coronary disease has been firmly established.

DISCUSSION

With an increase in use and popularity, a number of beneficial actions of the statins unrelated to their cholesterol-lowering ability have been reported. These effects have generated greater interest in the possible additional roles and indications for the use of these drugs. Of central focus in this paper is the cholesterol-independent benefit of this group of agents on the cardiovascular system, particularly on the lowering of systemic blood pressure. A number of hypotheses have been proposed for this action and these shall be reviewed within this paper.

CONCLUSION

We explore recent data that suggests that statins may provide substantial reduction of blood pressure in the hypertensive, hypercholesterolemic patient independent of their lipid-lowering effect. In addition, we review several notable publications that postulate unique mechanisms for this action and benefit. We also present plausible explanations as to why some of the larger statin trials did not report similar such findings.

Age-induced hypercholesterolemia in the rat relates to reduced elimination but not increased intestinal absorption of cholesterol

Plasma cholesterol increases in normal aging in both rodents and humans. This is associated with reduced elimination of cholesterol as bile acids (BAs) and decreased receptor-mediated clearance of plasma LDL, changes that can be reversed by treatment with growth hormone (GH). The level of intestinal absorption of cholesterol may also contribute to the development of hypercholesterolemia. In this study, we investigated whether cholesterol absorption increases with age and whether any such age-related change could be influenced by treatment with GH or ezetimibe (EZE). Male rats aged 6 and 18 mo were studied with and without GH or EZE treatment. BA synthesis was reduced and plasma cholesterol was increased in the old animals, whereas cholesterol absorption was unaltered. Cholesterol absorption was not altered by GH treatment but was reduced by EZE in both groups of animals. Hepatic LDL receptors (LDLRs), scavenger receptor class B type 1, and proprotein convertase subtilisin/kexin type 9 serine protease (PCSK9) transcripts were unchanged in old animals. GH treatment induced LDLRs, PCSK9 transcripts, and BA synthesis. We conclude that the age-induced hypercholesterolemia in the rat and its reversal by GH treatment relates to altered degradation of cholesterol in the liver and is not due to changes in cholesterol absorption.

Effects of Flavonoid-Containing Beverages and EGCG on Endothelial Function

Abnormalities of the vascular endothelium contribute to all stages of atherosclerosis from lesion development to clinical cardiovascular disease events. Recognized risk factors, including diabetes mellitus, hypertension, dyslipidemia, cigarette smoking, and sedentary lifestyle are associated with endothelial dysfunction. A variety of pharmacological and behavioral interventions have been shown to reverse endothelial dysfunction in patients with cardiovascular disease. A large number of epidemiological studies suggest that dietary factors, including increased intake of flavonoid-containing foods and beverages, reduce cardiovascular risk, and recent studies have shown that such beverages have favorable effects on endothelial function. These studies have engendered interest in the development of dietary supplements or drugs that would allow for more convenient and higher dose administration of flavonoids and might prove useful for prevention or treatment of cardiovascular disease. In this paper, we will review the contribution of endothelial dysfunction to the pathogenesis and clinical expression of atherosclerosis and recent data linking flavonoid and EGCG consumption to improved endothelial function and reduced cardiovascular risk.

Understanding risk in hypercholesterolemia

Atherosclerosis was relatively uncommon 100 years ago, when researchers first established its link to elevated cholesterol. As the twentieth century progressed, however, factors such as high-fat diets, sedentary lifestyles, cigarette smoking, and urbanization combined to increase the prevalence of both hypercholesterolemia and coronary heart disease (CHD) throughout the developed world. Atherogenesis begins at an early age and progresses throughout life, and cholesterol levels during young adulthood strongly predict the risk of CHD and related mortality during the ensuing decades. The total cholesterol level in youth also determines the actual age at which a critical level of atherosclerosis will be reached. Early studies on the primary and secondary prevention of CHD failed to identify a linear relationship between lipid lowering and risk reduction, primarily because older lipid-lowering agents lacked the potency to reduce cholesterol levels significantly enough to achieve lower cardiovascular event and mortality rates. The introduction of the statins, with their powerful lipid-lowering activity, overcame this limitation. Several large-scale trials of statins firmly established the efficacy of these agents in both primary and secondary CHD prevention. With the availability of statin therapy, we are now able to reduce the risk of major adverse CHD events by an average of 30%, regardless of patient age or gender.

No effect of glucagon-like peptide-1 on short-term satiety and energy intake in man

Centrally administered glucagon-like peptide-1 (GLP-1) inhibits feeding in fasted rats, but its role in human satiety has been largely unexplored. The present study investigated the effect of peripheral GLP-1 infusion on gastric emptying and satiety in man. Ten non-obese male subjects were infused in a randomized single-blind within-subject crossover study using saline infusion as control. They received either a GLP-1 infusion (1·2 pmol/kg per min) or a saline infusion for 1 h, at 18.00 hours. At 20 min after starting the infusion the gastric emptying of a 400 ml water load was measured. Subjects completed behavioural self-rating scales to assess hunger and satiety. After 40 min subjects were given a buffet mealad libitumand their food intake was recorded. GLP-1 infusion raised circulating GLP-1 concentrations to approximately twice those seen following a meal. It did not affect circulating insulin levels but caused a small fall in glucose levels. Gastric emptying of the water load was significantly delayed by the GLP-1 infusion. Energy intake from the buffet was unaffected by GLP-1 infusion. Self-assessment of hunger and satiety was similarly unaffected by the infusion before the buffet meal, although subjects tended to be less hungry after the buffet meal following GLP-1 infusion (P< 0·09). GLP-1 infusion delayed gastric emptying but had a minimal effect on food intake and satiety. This study casts doubts on whether GLP-1 is a major satiety factor in man, although a raised circulating plasma glucose level, as would normally occur postprandially, might be necessary for GLP-1 to increase satiety.

Spreads enriched with plant sterols, either esterified 4,4-dimethylsterols or free 4-desmethylsterols, and plasma total- and LDL-cholesterol concentrations

In a 9-week study seventy-six healthy adult volunteers with an average age of 44 (sd11) years, with baseline plasma total cholesterol levels below 8 mmol/l, received in a balanced, double-blind, crossover design, a total of three different table spreads for personal use. Two spreads were fortified either with free (non-esterified) vegetable-oil sterols, mainly from soyabean oil (31 g sterol equivalents/kg; 0·8 g/d) or sheanut-oil sterols (133 g sterol equivalents/kg; 3·3 g/d). One spread was not fortified (control). Average intake of spread was 25 g/d for 3 weeks. None of the spreads induced changes in blood clinical chemistry or haematology. Plasma total- and LDL-cholesterol concentrations were statistically significantly reduced by 3·8% and 6% (both 0·19 mmol/l) respectively, for the spread enriched with free soyabean-oil sterols compared with the control spread. The spread enriched with sheanut-oil sterols did not lower plasma total- and LDL-cholesterol levels. None of the plant-sterol-enriched spreads affected plasma HDL-cholesterol concentrations. Plasma-lipid-standardized concentrations of α- plus β-carotene were not statistically significantly affected by the soyabean-oil sterol spread in contrast to lipid-standardized plasma lycopene levels which showed a statistically significant decrease (9·5%). These findings indicate that a daily intake of free soyabean-oil sterols as low as 0·8 g added to a spread is effective in lowering blood total- and LDL-cholesterol levels with limited effects on blood carotenoid levels. The lowering in total- and LDL-cholesterol blood levels due to consumption of the vegetable-oil-sterol-enriched spread may be helpful in reducing the risk of CHD for the population.

AMELIORATIVE EFFECT OF CHLOROPHYTUM BORIVILIANUM ROOT ON LIPID METABOLISM IN HYPERLIPAEMIC RATS

1. The present study examined the efficacy of Chlorophytum borivilianum root (powder) in modulating the hyperlipaemic/hypercholesteraemic conditions in male albino rats. 2. Administration of C. borivilianum (0.75 and 1.5 g root powder/rat per day for 4 weeks) to hypercholesteraemic rats significantly increased high-density lipoprotein-cholesterol levels and decreased plasma and hepatic lipid profiles. 3. In addition, there were significant increases in faecal cholesterol, neutral sterol and bile acid excretion with elevated hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and bile acid production. 4. Furthermore, the hypercholesteraemic rats treated with both doses of C. borivilianum also exhibited increases in superoxide dismutase and ascorbic acid levels. 5. Normocholesteraemic animals treated with both doses of C. borivilianum root powder did not show any significant variation in either lipid or anti-oxidant profiles, except for an increase in the hepatic ascorbic acid concentration compared with their untreated counterparts. 6. The hypolipaemic/hypocholesteraemic effect of C. borivilianum root powder appears to be mediated by an increase in cholesterol turnover via increased faecal cholesterol excretion and, second, through an endogenous cholesterol conversion into bile acid. 7. Administration of C. borivilianum root powder also increased the activities of anti-oxidant enzymes and vitamin C levels, which may have enhanced the anti-oxidant capacity of the liver.

Regulation of endothelial nitric-oxide synthase activity through phosphorylation in response to epoxyeicosatrienoic acids

Endothelial nitric oxide synthase (eNOS) is a key enzyme in NO-mediated cardiovascular homeostasis and its activity is modulated by a variety of hormonal and mechanical stimuli via phosphorylation modification. Our previous study has demonstrated that epoxyeicosatrienoic acids (EETs), the cytochrome P450 (CYP)-dependent metabolites of arachidonic acid, could robustly up-regulate eNOS expression. However, the molecular mechanism underlying the effects of EETs on eNOS remains elusive. Particularly, whether and how EETs affect eNOS phosphorylation is unknown. In the present study, we investigated the effects of EETs on eNOS phosphorylation with cultured bovine aortic endothelial cells (BAECs). BAECs were either treated with exogenous EETs or infected with recombinant adeno-associated virus (rAAV) carrying CYP2C11-CYPOR, CYP102 F87V mutant and CYP2J2, respectively, to increase endogenous EETs. Both addition of EETs and CYP epoxygenase transfection markedly increased eNOS phosphorylation at its Ser1179 and Thr497 residues. Inhibition of phosphatidylinositol 3-kinase (PI3K) with LY294002 prevented EETs-induced increases of eNOS-Ser(P)1179 but had no effect on the phosphorylation status of Thr497. However, inhibitors of protein kinase B (Akt), mitogen-activated protein kinase (MAPK) and MAPK kinase could block phosphorylation of eNOS at both sites. Inhibition of these kinases also attenuated the up-regulation of eNOS expression by EETs. Finally, administration of viral CYP epoxygenases expression vectors into rats enhanced eNOS phosphorylation and function in vivo. Thus, in addition to up-regulating eNOS expression, EETs also augment eNOS function by enhancing eNOS phosphorylation. EETs-induced up-regulation of eNOS phosphorylation and expression appears to involve in both PI3K/Akt and MAPK pathways.

[Atherosclerosis plaque regression]

INTRODUCTION

The natural history of atherosclerosis can be assessed using different methods including quantitative coronary angiography, intravascular ultrasound, B-mode ultrasound, electron-beam computed tomography and magnetic resonance imaging.

REGRESSION OF ATHEROSCLEROSIS

Although the first investigations regarding effects of low cholesterol diet on atherosclerosis progression in animals were performed almost 100 years ago, researches on potential induction of atherosclerosis regression in humans began only recently, in the past 20 years. To date, many studies assessing different drugs and study protocols on natural evolution of atherosclerosis have been performed. They include use of diet and physical activity, different hypolipemic drugs, especially statins, ACE inhibitors, calcium channel blockers, hormone replacement therapy, antioxidants, and recently, use of recombinant apolipoproteins.

STATINS AND ATHEROSCLEROSIS

It has been established that statins given to patients with, or even without verified coronary artery disease, slow progression of atherosclerosis. These effects of statins are likely due to a combination of their metabolic and pleiotropic properties and might in part explain the positive effects of these drugs on overall cardiovascular mortality and morbidity. Furthermore, applied in high doses, these drugs may induce real atherosclerosis regression, especially in asymptomatic patients in the early stages of the disease.

Statin Withdrawal: Clinical Implications and Molecular Mechanisms

Retrospective analyses of data from the Platelet Receptor Inhibition in Ischemic Syndrome Management (PRISM), the National Registry of Myocardial Infarction 4, and the Global Registry of Acute Coronary Events (GRACE) trials revealed that the benefits of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) on acute coronary outcomes are rapidly lost and outcomes worsened if statins are discontinued during a patient's hospitalization for an acute coronary syndrome. Withdrawal of statin therapy in the first 24 hours of hospitalization for non-ST-elevation myocardial infarction increased the hospital morbidity and mortality rate versus continued therapy (11.9% vs 5.7%, p<0.01). Data from the Treating New Targets (TNT) study, however, suggested that short-term discontinuation of statin therapy in patients with stable cardiac conditions may not substantially increase the risk of acute coronary syndromes. In patients with acute coronary syndromes who discontinue statins, the rapid increase in risk of an event may result not only from the lost benefits from the therapy, but also from rebound inhibition of vascular protective substances and activation of vascular deleterious substances. Statins inhibit cholesterol synthesis in vascular cells. By reducing levels of isoprenoid intermediates, statins increase the production of nitric oxide and downregulate angiotensin II AT(1) receptors, endothelin-1, vascular inflammatory adhesion molecules, and inflammatory cytokines. These benefits are rapidly lost and often transiently reversed when statins are acutely discontinued. Acute removal of pleiotropic effects and rebound vascular dysfunction may be more important in an acute coronary event, where inflammation promotes rupture of atherosclerotic plaques and inflammatory and prothrombosis markers are present in high concentration, than in stable chronic vascular disease. In the absence of data from randomized controlled trials, current information suggests that statin therapy should be continued, and possibly boosted, during hospitalization for an acute coronary syndrome. Because statins are discontinued during the early hospitalization of many patients, practitioners must ensure that statins are not omitted, unless contraindicated, from the treatment of patients with acute coronary syndromes.

Statin therapy in patients with chronic kidney disease: to use or not to use

Dyslipdemia is a common complication of chronic kidney disease (CKD) and contributes to high cardiovascular morbidity and mortality of CKD patients. Experimental studies have demonstrated that lipids induce glomerular and tubulointerstitial injury and that lipid-lowering treatments ameliorate renal injury. Therapy with statins not only has the potential to lower cardiovascular morbidity and mortality in patients with CKD but also to slow progression of renal disease. Whereas the guidelines for treatment of hyperlipidaemia in nonrenal patients are based on prospective, randomized, placebo-controlled mega-trials, such data are not available for CKD patients. This review outlines the limited information currently available on the effect of statins among patients with CKD and summarizes the ongoing randomized trials designed to address this question.

Heritability of cardiovascular and personality traits in 6,148 Sardinians

In family studies, phenotypic similarities between relatives yield information on the overall contribution of genes to trait variation. Large samples are important for these family studies, especially when comparing heritability between subgroups such as young and old, or males and females. We recruited a cohort of 6,148 participants, aged 14–102 y, from four clustered towns in Sardinia. The cohort includes 34,469 relative pairs. To extract genetic information, we implemented software for variance components heritability analysis, designed to handle large pedigrees, analyze multiple traits simultaneously, and model heterogeneity. Here, we report heritability analyses for 98 quantitative traits, focusing on facets of personality and cardiovascular function. We also summarize results of bivariate analyses for all pairs of traits and of heterogeneity analyses for each trait. We found a significant genetic component for every trait. On average, genetic effects explained 40% of the variance for 38 blood tests, 51% for five anthropometric measures, 25% for 20 measures of cardiovascular function, and 19% for 35 personality traits. Four traits showed significant evidence for an X-linked component. Bivariate analyses suggested overlapping genetic determinants for many traits, including multiple personality facets and several traits related to the metabolic syndrome; but we found no evidence for shared genetic determinants that might underlie the reported association of some personality traits and cardiovascular risk factors. Models allowing for heterogeneity suggested that, in this cohort, the genetic variance was typically larger in females and in younger individuals, but interesting exceptions were observed. For example, narrow heritability of blood pressure was approximately 26% in individuals more than 42 y old, but only approximately 8% in younger individuals. Despite the heterogeneity in effect sizes, the same loci appear to contribute to variance in young and old, and in males and females. In summary, we find significant evidence for heritability of many medically important traits, including cardiovascular function and personality. Evidence for heterogeneity by age and sex suggests that models allowing for these differences will be important in mapping quantitative traits.

Genetic analysis of complex traits, which are influenced by many different variables, is difficult because different genes and environmental factors can affect each individual. To simplify analysis, the authors turned to Sardinia, one of the rare, relatively isolated populations. They recruited 6,148 participants, aged 14–102 y, from four neighboring towns. Their sample includes many related individuals, including, for example, approximately 5,000 pairs of brothers and sisters. The authors measured 98 traits in each individual, including different aspects of blood composition and several cardiovascular and personality measures.

Here, the authors evaluate the overall impact of genes and environment on each trait and show that genes can explain many of the differences and similarities between individuals. Genetic influences were typically larger in females and in younger individuals, but interesting exceptions were observed. For example, genetic factors accounted for approximately 26% of the variation in blood pressure for those more than 42 y old, but only for approximately 8% in younger individuals. Their analysis also showed that the same genetic factor could influence multiple traits, for example by affecting multiple features of personality or of cardiovascular function. DNA analyses of this cohort will eventually allow researchers to identify genes that affect each of the traits studied, including important risk factors for cardiovascular disease.

Analysis of five HMG-CoA reductase inhibitors-- atorvastatin, lovastatin, pravastatin, rosuvastatin and simvastatin: pharmacological, pharmacokinetic and analytical overview and development of a new method for use in pharmaceutical formulations analysis and in vitro metabolism studies

A specific, accurate, precise and reproducible high-performance liquid chromatographic (HPLC) method was developed and validated for the simultaneous quantitation of five 3-hydroxy-3-methyglutaryl coenzyme A (HMG-CoA) reductase inhibitors, viz. atorvastatin, lovastatin, pravastatin, rosuvastatin and simvastatin, in pharmaceutical formulations and extended the application to in vitro metabolism studies of these statins. Ternary gradient elution at a flow rate of 1 mL/min was employed on an Intertisl ODS 3V column (4.6 x 250 mm, 5 microm) at ambient temperature. The mobile phase consisted of 0.01 m ammonium acetate (pH 5.0), acetonitrile and methanol. Theophylline was used as an internal standard (IS). The HMG-CoA reductase inhibitors and their metabolites were monitored at a wavelength of 237 nm. Drugs were found to be 89.6-105.6% of their label's claim in the pharmaceutical formulations. For in vitro metabolism studies the reaction mixtures were extracted with simple liquid-liquid extraction using ethyl acetate. Baseline separation of statins and their metabolites along with IS free from endogenous interferences was achieved. Nominal retention times of IS, atorvastatin, lovastatin, pravastatin, rosuvastatin and simvastatin were 7.5, 17.2, 21.6, 28.5, 33.5 and 35.5 min, respectively. The proposed method is simple, selective and could be applicable for routine analysis of HMG-CoA reductase inhibitors in pharmaceutical preparations as well as in vitro metabolism studies.

Endothelial Function, Nitric Oxide, and Cocoa Flavanols

Endothelial dysfunction is the pathophysiologic principle involved in the initiation and progression of arteriosclerosis, thus endothelial function serves as a "barometer" for cardiovascular health that can be used for the evaluation of new therapeutic strategies. This review provides an introduction to the concept of endothelial dysfunction, and it explores the importance of this prognostic marker in the context of clinical, dietary interventions in humans. Moreover, we summarize and evaluate the findings of various clinical trials that demonstrated an improvement of endothelial dysfunction in subjects with cardiovascular risk factors after the acute and chronic consumption of flavanol-rich foods, including cocoa products, red wine, and tea.

The protective role of Chinese prescription Kangen-karyu extract on diet-induced hypercholesterolemia in rats

This study was carried out to investigate the protective potential of Chinese prescription Kangen-karyu, comprising six crude drugs, on coronary heart disease which is the principal cause of morbidity and mortality worldwide. The diet-induced hypercholesterolemic rat model, which shows an elevation in low density lipoprotein (LDL) cholesterol and atherosclerosis, was employed. The control rats fed a diet of 1% cholesterol and 0.5% cholic acid showed the highest cholesterol levels in serum and feces relative to those fed a normal diet, however, the rats administered Kangen-karyu extract showed reductions in these levels without changes in liver cholesterol, indicating that the reduction of serum total cholesterol by Kangen-karyu extract probably arises from an increase in cholesterol excretion. Furthermore, the administration of Kangen-karyu extract significantly prevented the elevation of serum aspartate aminotransferase and alanine aminotransferase, known as marker enzymes of liver damage. The elevated serum levels of LDL cholesterol were lowered, however, the high density lipoprotein cholesterol level was significantly elevated by Kangen-karyu extract and these were dose-dependent decreases in the atherogenic index to 15.2, 8.8 and 7.5 at oral doses of 50, 100 and 200 mg from the 19.4 control value, respectively. In addition, Kangen-karyu extract inhibited LDL oxidation in a dose-dependent manner, and the elevated level of thiobarbituric acid-reactive substances in control rats showed a decline by the administration of Kangen-karyu extract. The present study suggests that Kangen-karyu could play a protective role against hypercholesterolemia through the regulation of cholesterol levels and inhibition of lipid peroxidation.

Drug and bile acid transporters in rosuvastatin hepatic uptake: function, expression, and pharmacogenetics

BACKGROUND & AIMS

The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, or statins, target liver HMG-CoA and are of proven benefit in the prevention of coronary heart disease. Rosuvastatin is an effective statin notable for liver selectivity and lack of significant metabolism. We assessed the extent and relevance of hepatic transporters to rosuvastatin uptake.

METHODS

Transporters involved in rosuvastatin uptake were determined through heterologous expression of multiple human and rat uptake transporters. Human organic anion transporting polypeptide (OATP) 1B1 and sodium-dependent taurocholate cotransporting polypeptide (NTCP) allelic variants were also assessed. Expression of OATP and NTCP messenger RNA and protein was determined from a bank of human liver samples.

RESULTS

Multiple OATP family members, including 1B1, 1B3, 2B1, and 1A2, were capable of rosuvastatin transport. Naturally occurring polymorphisms in OATP1B1, including *5, *9, *15, and *18, were associated with profound loss of activity toward rosuvastatin. Interestingly, the major human hepatic bile acid uptake transporter NTCP, but not rat Ntcp, also transported rosuvastatin. Human hepatocyte studies suggested that NTCP alone accounted for approximately 35% of rosuvastatin uptake. Remarkably, NTCP*2, a variant known to have a near complete loss of function for bile acids, exhibited a profound gain of function for rosuvastatin. Quantitative messenger RNA analysis revealed marked intersubject variability in expression of OATPs and NTCP.

CONCLUSIONS

Multiple transporters mediate the overall hepatic uptake of rosuvastatin, and NTCP may be a heretofore unrecognized transporter important to the disposition of rosuvastatin and possibly other drugs/statins in clinical use. Accordingly, transporter expression and polymorphisms may be key determinants of intersubject variability in response to statin therapy in general.

Influence of Acute Renal Failure on Coronary Vasoregulation in Dogs

Impaired renal function is associated with an increased risk for cardiovascular events and death, but the pathophysiology is poorly defined. The hypothesis that coronary blood flow regulation and distribution of ventricular blood flow could be compromised during acute renal failure (ARF) was tested. In two separate groups (n = 14 each) of dogs with ARF, (1) coronary autoregulation (pressure-flow relations), vascular reserve (reactive hyperemia), and myocardial blood flow distribution (microspheres) and (2) coronary vessel responses to intracoronary infusion of select endothelium-dependent and -independent vasodilators were evaluated. In addition, coronary pressure-flow relations and vascular reserve after inhibition of nitric oxide and prostaglandin release were evaluated. Under resting conditions, myocardial oxygen consumption increased in dogs with ARF compared with no renal failure (NRF; 11.8 +/- 9.2 versus 5.0 +/- 1.5 ml O(2)/min per 100 g; P = 0.01), and the autoregulatory break point of the coronary pressure-flow relation was shifted to higher diastolic coronary pressures (60 +/- 17 versus 52 +/- 8 mmHg in NRF; P = 0.003); the latter was shifted further rightward after inhibition of both nitric oxide and prostaglandin release. The endocardial/epicardial blood flow ratio was comparable for both groups, suggesting preserved ventricular distribution of blood flow. In dogs with ARF, coronary vascular conductance also was reduced (P = 0.001 versus NRF), but coronary zero-flow pressure was unchanged. Vessel reactivity to each endothelium-dependent/independent compound also was blunted significantly. In conclusion, under resting conditions, coronary vascular tone, reserve, and vessel reactivity are markedly diminished with ARF, suggesting impaired vascular function. Consequently, during ARF, small increases in myocardial oxygen demand would induce subendocardial ischemia as a result of a limited capacity to increase oxygen supply and thereby contribute to higher risk for adverse coronary events and mortality.

3D QSAR study of hypolipidemic asarones by comparative molecular surface analysis

Three-dimensional quantitative structure-activity relationship (3D QSAR) modeled for alpha-asarone derivatives using the comparative molecular surface analysis (CoMSA) allowed us to reveal a correlation between the activity of these compounds and the electrostatic potential at the molecular surface. The grid formalism (s-CoMSA) allowed us to indicate a pharmacophore that is of key importance for compound activity. The CoMSA formalism coupled with the iterative variable elimination method gives a highly predictive model.

Prediction of cardiovascular and total mortality in Chinese type 2 diabetic patients by the WHO definition for the metabolic syndrome

AIM

The aim of this study is to investigate the prevalence of metabolic syndrome (MES) in type 2 diabetic patients and the predictive values of the World Health Organization (WHO) and National Cholesterol Education Programme (NCEP) definitions and the individual components of the MES on total and cardiovascular mortality.

METHODS

A prospective analysis of a consecutive cohort of 5202 Chinese type 2 diabetic patients recruited between July 1994 and April 2001.

RESULTS

The prevalence of the MES was 49.2-58.1% depending on the use of various criteria. There were 189 deaths (men: 100 and women: 89) in these 5205 patients during a median (interquartile range) follow-up period of 2.1 (0.3-3.6 years). Of these, 164 (87%) were classified as cardiovascular deaths. Using the NCEP criterion, patients with MES had a death rate similar to those without (3.51 vs. 3.85%). By contrast, based on the WHO criteria, patients with MES had a higher mortality rate than those without (4.3 vs. 2.4%, p = 0.002). Compared to patients with neither NCEP- nor WHO-defined MES, only the group with MES defined by the WHO, but not NCEP, criterion had significantly higher mortality rate (2.6 vs. 6.8%, p < 0.001). Using Cox regression analysis, only age, duration of diabetes and smoking were identified as independent factors for cardiovascular or total death. Among the various components of MES, hypertension, low BMI and albuminuria were the key predictors for these adverse events.

CONCLUSIONS

In Chinese type 2 diabetic patients, the WHO criterion has a better discriminative power over the NCEP criterion for predicting death. Among the various components of the MES defined either by WHO or NCEP, hypertension, albuminuria and low BMI were the main predictors of cardiovascular and total mortality.

Modulation of endothelial and smooth muscle function by bed rest and hypoenergetic, low-fat nutrition

Prolonged microgravity alters the regulation of the peripheral vasculature. The influence of reduced food intake, as often observed in astronauts, on vascular function is unclear. In a randomized, four-phase, crossover study, the effect of simulated microgravity (13 days of bed rest), energetic restriction (-25%, fat reduced), and their combination on endothelium-dependent and -independent vasodilation was compared with ambulatory control conditions. Using venous occlusion plethysmography, cumulative intra-arterial dose-response curves to endothelium-dependent (acetylcholine) and -independent (sodium nitroprusside) vasodilators were constructed in 10 healthy male volunteers before and on day 13 of each of the four intervention periods. Bed rest combined with normoenergetic nutrition impaired the dose-response to acetylcholine (ANOVA, P = 0.004) but not to sodium nitroprusside, whereas hypoenergetic diet under ambulatory conditions improved responses to acetylcholine (P = 0.044) and sodium nitroprusside (P < 0.001). When bed rest was combined with hypoenergetic diet, acetylcholine responses did not change. Similarly, under control conditions, no change was observed. Individual changes in the total cholesterol-to-HDL ratio were correlated with changes in endothelial and vascular smooth muscle relaxation. In conclusion, short-term bed rest impairs endothelium-dependent arterial relaxation in humans. A hypoenergetic, low-fat diet modulates serum lipids, improves endothelium-dependent and -independent relaxation, and may antagonize the unfavorable effects of simulated microgravity on endothelial function.

Effect of statins in stroke prevention

PURPOSE OF REVIEW

This paper reviews recent studies into the outcomes of clinical trials in which statin therapy has been used in the prevention and treatment of strokes.

RECENT DEVELOPMENTS

Epidemiologic studies found no or little association between blood cholesterol levels and stroke. Randomized trials have confirmed that LDL lowering decreased the risk of stroke, in diabetic or hypertensive patients with 'normal' LDL cholesterol at baseline, and in patients with coronary artery disease, with respectively 48, 27 and 25% reduction in stroke incidence. A meta-analysis of trials showed that the greater the LDL cholesterol reduction, the greater the intima-media thickness and stroke risk reductions. Even if statins also have 'pleiotropic' effects, their main action seems to be through LDL reduction. The Heart Protection Study only included strokes that occurred 4.6 years before--a time when the stroke event rate is low and the cardiac event rate is high, and so may not have had the power to find a true effect of LDL cholesterol lowering in preventing recurrent stroke. The Stroke Prevention by Aggressive Reduction in Cholesterol Levels (SPARCL) trial may give a definite answer because SPARCL investigators included 4732 patients with brain infarction or transient ischemic attacks and no history of myocardial infarction within 6 months of their stroke event, at a time when the expected stroke rate is very high and the myocardial infarction rate is very low. The results should be announced by mid-2006.

SUMMARY

The positive effect of statins on stroke observed in trials of patients with coronary heart disease depended mainly on between-group LDL reduction, but other mechanisms could be involved. Though effective in prevention of major coronary events after a first stroke, statins have not yet been proven effective in prevention of recurrent stroke.