Beneficial effects of cholesterol-lowering therapy on the coronary endothelium in patients with coronary artery disease

Fluvastatin and lovastatin but not pravastatin induce neuroglial differentiation in human mesenchymal stem cells

Recent studies have shown that statins, the most potent inhibitors of 3-hydroxy-2-methylglutaryl coenzyme A (HMG-CoA) reductase, stimulate bone formation in vitro and in rodents by activating the expression of bone morphogenetic protein-2 (BMP-2), one of the most critical osteoblast differentiation-inducing factors. However, the effect of statins on mesenchymal stem cells (MSCs) is yet to be reported. The purpose of this study is to investigate the influence of fluvastatin, lovastatin, and pravastatin, three commonly prescribed lipid-lowering agents, on the proliferation and differentiation of human MSCs. To our surprise, even though fluvastatin and lovastatin effectively suppressed the growth of human MSCs, a neuroglia rather than osteoblast-like morphology was observed after treatment. Interestingly, such morphological change was inhibited by the co-addition of geranylgeranyl pyrophosphate (GGPP). Immunofluorescence staining with antibodies against neuron-, astrocyte-, as well as oligodendrocyte-specific markers confirmed the neuroglial identity of the differentiated cells. However, BMP-2 is unlikely to play a positive role in neuroglial differentiation of MSCs since its expression was down-regulated in fluvastatin-treated cells. Taken together, our results suggest that fluvastatin and lovastatin induce neuroglial differentiation of human MSCs and that these cholesterol-lowering agents might be used in conjunction with MSC transplantation in the future for treating neurological disorders and injuries.

The case for intensive statin therapy after acute coronary syndromes

Acute coronary syndromes (ACS) consist of unstable angina or acute myocardial infarction and are associated with a high risk of early recurrent ischemic events. Revascularization procedures do not modify underlying pathophysiology and only modestly reduce early ischemic events after an index episode of ACS. Although statins improve dyslipidemia and cardiovascular risk over the long term, efforts to identify new ACS treatments are focusing on the ability of statins to modify the arterial wall-blood interface and reduce the risk of early recurrent ischemic events. Statins have been shown to reduce circulating markers of inflammation within days of an acute ischemic event. Short-term statin therapy also has been associated with improved coronary endothelial function, reversal of prothrombotic states, and reduction in atherosclerotic plaque volume. Findings from 6 randomized, controlled intervention trials were evaluated to determine if risk reduction is associated with the intensity of statin therapy. In addition, the predictive ability of baseline lipid levels and inflammatory markers were examined. High-intensity statin therapy (atorvastatin 80 mg) reduced early recurrent ischemic events after ACS compared with moderate-intensity treatment (eg, pravastatin 40 mg) or placebo. Moderate-intensity regimens (simvastatin 40 mg, pravastatin 20 to 40 mg, fluvastatin 80 mg, cerivastatin 0.4 mg) provided minimal benefit compared with placebo. Although there was no apparent relation between low-density lipoprotein (LDL) cholesterol levels before or during randomized treatment and short-term (4-month) risk of recurrent events, the degree of LDL cholesterol reduction with statin treatment after ACS may be related to longer-term event reduction. Moreover, evidence suggests that anti-inflammatory effects of high-intensity statin treatment are associated with clinical benefit.

Effects of statins on 3-hydroxy-3-methylglutaryl coenzyme a reductase inhibition beyond low-density lipoprotein cholesterol

Statins are potent inhibitors of cholesterol biosynthesis and exert beneficial effects in the primary and secondary prevention of coronary artery disease. However, the overall benefits observed with statins appear to occur much earlier and to be greater than what might be expected from changes in lipid levels alone, suggesting effects beyond cholesterol lowering. Indeed, recent studies indicate that some of the cholesterol-independent or "pleiotropic" effects of statins involve improving endothelial function, enhancing the stability of atherosclerotic plaques, decreasing oxidative stress and inflammation, and inhibiting the thrombogenic response. Many of these pleiotropic effects are mediated by inhibition of isoprenoids, which serve as lipid attachments for intracellular signaling molecules. In particular, inhibition of the small guanosine triphosphate-binding proteins Rho, Ras, and Rac, whose proper membrane localization and function are dependent on isoprenylation, may play an important role in mediating the pleiotropic effects of statins.

Red wine reduces oxidative stress in patients with acute coronary syndrome

BACKGROUND

Moderate red wine consumption improved endothelial function in normal volunteers. Herein we explored the effects of moderate red wine consumption in endothelial function and in oxidative stress in patients with an acute coronary syndrome.

METHODS

20 patients treated with percutaneous coronary interventions after an acute coronary syndrome were randomized to a red-wine group (n=9, 250 ml daily, Cabernet Sauvignon) or to a control group (n=11, abstinence from alcoholic beverages). Studies were performed at baseline and after 2 months. Endothelial function was estimated by flow-mediated vasodilatation of the brachial artery. Plasma antioxidant capacity was measured by total antioxidant reactivity and ferric reducing antioxidant power. Oxidative damage was evaluated by measurements of 8-OH deoxyguanosine content in leukocyte deoxyribonucleic acid.

RESULTS

The endothelium dependent/independent dilatation ratio significantly improved compared to baseline in both groups. The 8-OH deoxyguanosine content decreased significantly in both groups; this effect was more pronounced with wine (p<0.002 vs. control). Oxidative deoxyribonucleic acid damage in controls decreased from 13.1+/-1.1 to 10.0+/-1.0 (p<0.003); with wine from 13+/-0.8 to 5.6+/-0.7 per 10(5) guanosines (p<0.001; p<0.002 vs. control). Total antioxidant reactivity increased from 240+/-18 to 268+/-18 microM in the control group and from 273+/-20 to 330+/-15 microM in the wine group (p<0.03 vs. control). Ferric reducing antioxidant power increased from 1106+/-60 to 1235+/-42 microM in the control group and from 1219+/-82 to 1450+/-63 microM in the wine group (p<0.001 vs. control).

CONCLUSIONS

The addition of moderate amounts of red wine did not improve endothelial function beyond conventional therapy, whereas it showed benefits in parameters of oxidative stress in these patients.

Long-term effects of antilipidaemic therapy on left ventricular function in patients with dyslipidaemia: multigated radionuclide ventriculography study

AIM

It has been reported that dyslipidaemia impairs left ventricular systolic (LVs) and diastolic (LVd) functions, irrespective of atherogenic effects, in the setting of coronary artery disease. The aim of the present study was to evaluate the effects of anti-lipidaemic therapy on LVs and LVd functions by means of multigated radionuclide ventriculography (RNV) in subjects with signs of dyslipidaemia and with preserved left ventricular function.

METHODS

Eighteen patients with dyslipidaemia (eight men, 10 women, mean age 50+/-10 years) were included in the study. While the clinical examination and treadmill exercise test results were normal in all patients, low-density lipoprotein levels exceeded 160 mg . dl. Patients with medical conditions including coronary artery disease, hypertension, diabetes, cardiomyopathy and valvular heart disease which would influence left ventricular function were excluded from the study. RNV was performed in all subjects, taking into account the best septal position to differentiate the left ventricle from the right ventricle. The following parameters were calculated: ejection fraction, peak ejection rate (PER), time to peak ejection (TPER), a ejection rate (aER), a ejection fraction (aEF), Peak filling rate (PFR), time to peak filling rate (TPFR), a filling rate (aFR), a filling fraction (aFF).

RESULTS

The low-density lipoprotein value decreased and the high-density lipoprotein value increased after statin therapy (P<0.001 and P<0.003, respectively). PER, aER and aFF significantly increased and TPER decreased as a consequence of statin therapy (respectively, P<0.05, P<0.05, P<0.05 P<0.05).

CONCLUSION

Anti-lipidaemic therapy is effective in dyslipidaemic patients. RNV is a useful and non-invasive method for monitoring changes in ventricular function following anti-lipidaemic treatment strategies.

Insulin resistance and the endothelium

Type 2 diabetes is a cardiovascular disease equivalent that is associated with accelerated atherosclerosis and significant mortality. However, the metabolic syndrome and prediabetes are associated with increased cardiovascular mortality, indicating that atherogenic vascular changes begin prior to the onset of overt diabetes. At the core of diabetes and the metabolic syndrome is insulin resistance (IR), which sets the stage for dyslipidemia, hypertension, and inflammation. Endothelial dysfunction is the first stage of the atherosclerosis process and results from exposure to cardiovascular risk factors, such as IR and diabetes. IR and atherosclerosis follow parallel paths as they progress in severity. Thiazolidinediones, angiotensin-converting enzyme inhibitors, angiotensin receptor-AT1 blockers, and statins are widely used in the treatment of diabetes. Emerging evidence indicates that these pharmacologic agents have added mechanisms of action, especially on the endothelium and in the prevention of diabetes.

Clinical impact of vasomotor function assessment and the role of ACE-inhibitors and statins

Impaired endothelial function is recognised as one of the earliest events of atherogenesis. Endothelium-dependent vasomotion has been the principal method to assess endothelial function. In this article, we will discuss the clinical value of the different techniques to evaluate endothelium-dependent vasomotion. To date, there seems not to be a simple and reliably endothelial function test to identify asymptomatic subjects at increased risk for cardiovascular disease in clinical practice. Recent studies indicate that pharmacological interventions, in particular with ACE-inhibitors and statins, might improve endothelial function. However, there is no solid evidence that improvement of endothelial function is a necessity for the observed reduction in cardiovascular events by these compounds. Overall, at this moment, there is no place in clinical practice for the use of endothelial function as a method for risk assessment or target of pharmacological interventions.

Combination Therapy with Cerivastatin and Nifedipine Improves Endothelial Dysfunction After Balloon Injury in Porcine Coronary Arteries

HMG-CoA reductase inhibitors and calcium channel blockers have antiatherogenic effects; however, their mechanisms remain to be elucidated. This study examined the effect of cerivastatin and/or nifedipine on the endothelial dysfunction in porcine balloon-injured coronary arteries. Normal male pigs were randomly divided into the following four groups: control, cerivastatin (1 mg/kg/d PO), nifedipine (4 mg/kg/d PO), and their combination (n = 10 each). We started the treatments 3 days before balloon injury in the proximal left coronary arteries and continued for 4 weeks after the procedure. Then, we examined endothelial vasodilator functions ex vivo in organ chambers and in vitro by Western blotting for eNOS expression. Endothelium-dependent relaxations to serotonin, but not those to bradykinin or the calcium ionophore A23187 or endothelium-independent relaxations to sodium nitroprusside, were significantly impaired by balloon injury. The monotherapy with cerivastatin or nifedipine partially improved, and their combination supernormalized the relaxations to serotonin without affecting those to bradykinin or A23187 or endothelium-independent relaxations to sodium nitroprusside. The expression of eNOS was significantly reduced by balloon injury and normalized by the combination therapy. These results indicate that the combination therapy improves endothelial dysfunction after balloon injury, in which the up-regulation of eNOS may be involved.

Pleiotropic effects of statins

Statins are potent inhibitors of cholesterol biosynthesis. In clinical trials, statins are beneficial in the primary and secondary prevention of coronary heart disease. However, the overall benefits observed with statins appear to be greater than what might be expected from changes in lipid levels alone, suggesting effects beyond cholesterol lowering. Indeed, recent studies indicate that some of the cholesterol-independent or "pleiotropic" effects of statins involve improving endothelial function, enhancing the stability of atherosclerotic plaques, decreasing oxidative stress and inflammation, and inhibiting the thrombogenic response. Furthermore, statins have beneficial extrahepatic effects on the immune system, CNS, and bone. Many of these pleiotropic effects are mediated by inhibition of isoprenoids, which serve as lipid attachments for intracellular signaling molecules. In particular, inhibition of small GTP-binding proteins, Rho, Ras, and Rac, whose proper membrane localization and function are dependent on isoprenylation, may play an important role in mediating the pleiotropic effects of statins.

Cardiovascular functional phenotypes and pharmacological responses in apolipoprotein E deficient mice

This is an overview of recent findings, mainly from our laboratory, describing the cardiovascular functional phenotypes and pharmacological responses in mice genetically deficient in apolipoprotein E (apoE-KO). ApoE-KO mice are hyperlipidemic and spontaneously develop atherosclerosis. We have detected several new cardiovascular functional phenotypes in apoE-KO mice: hyperglycemia, age-dependent aortic stiffening, cardiac hypertrophy and increased cardiac output. Angiotensin II (Ang II) promoted vascular inflammation and atherosclerosis, increased vascular stiffness, and induced abdominal aortic aneurysm (AAA) in apoE-KO mice, in which activation of NF-kappaB mediated pro-inflammatory genes plays an important role. Inhibition of nitric oxide (NO) synthesis with N(omega)-nitro-L-arginine methyl ester (L-NAME) significantly inhibited NO-mediated vascular responses and accelerated atherosclerosis in apoE-KO mice, supporting a protective role of NO against atherosclerosis. Estrogen attenuated atherosclerosis in apoE-KO mice, even in those with atherosclerosis being accelerated by Ang II, hyperglycemia, or L-NAME, demonstrating an anti-atherosclerotic effect of estrogen. Simvastatin paradoxically increased lipid and atherosclerosis in apoE-KO mice, but it decreased lipid and atherosclerosis in LDLR-KO mice, indicating that anti-atherosclerotic effect of simvastatin requires the presence of an intact apoE.

Relation of the use of lipid-lowering medications prior to percutaneous coronary intervention to the incidence of intraprocedural adverse angiographic events

The use of lipid-lowering medications at the time of percutaneouscoronary intervention (PCI) has been shown to have a favorable effect on rates of cardiac enzyme elevation and major adverse cardiac events (MACEs), but the effect of these medications on angiographically identifiable intraprocedural coronary events during PCI has not previously been investigated. A retrospective review of 81 patients was performed and demonstrated that the use of lipid-lowering medications at the time of PCI was associated with a reduced incidence of angiographically identifiable intraprocedural events (odds ratio 0.13, 95% confidence interval 0.04 to 0.40). A multivariate analysis revealed that lipid-lowering medications and hyperlipidemia did not predict MACEs independent of the occurrence of these angiographic events.

Effect of Intensive Lipid Lowering, With or Without Antioxidant Vitamins, Compared With Moderate Lipid Lowering on Myocardial Ischemia in Patients With Stable Coronary Artery Disease

Background— Lipid lowering with statins prevents adverse cardiac events. Both lipid-lowering and antioxidant therapies may favorably affect vasomotor function and thereby improve ischemia.

Methods and Results— In a randomized, double-blind, placebo-controlled trial, 300 patients with stable coronary disease, a positive exercise treadmill test, 48-hour ambulatory ECG with ≥1 episode of ischemia, and fasting total cholesterol of 180 to 250 mg/dL were assigned to 1-year treatment with intensive atorvastatin to reduce LDL to <80 mg/dL (n=96), intensive atorvastatin to reduce LDL to <80 mg/dL plus antioxidant vitamins C (1000 mg/d) and E (800 mg/d) (n=101), or diet and low-dose lovastatin, if needed, to reduce LDL to <130 mg/dL (n=103; control group). Ischemia end points, including ambulatory ECG monitoring and exercise treadmill testing, and endothelial assessment using brachial artery flow-mediated dilation were obtained at baseline and at 6 and 12 months. Baseline characteristics were similar in all groups. LDL decreased from ≈153 mg/dL at baseline in the 2 atorvastatin groups to ≈83 mg/dL at 12 months (each P <0.0001) and from 147 to 120 mg/dL in the control group ( P <0.0001). During ambulatory ECG monitoring, mean number of ischemic episodes per 48 hours decreased 31% to 61% in each group (each P <0.001; P =0.15 across groups), without a change in daily heart rate activity. Mean duration of ischemia for 48 hours decreased 26% to 62% in each group (each P <0.001; P =0.06 across groups). Mean exercise duration to 1-mm ST-segment depression significantly increased in each group, but total exercise duration and mean sum of maximum ST depression were unchanged. Angina frequency decreased in each group. There was no incremental effect of supplemental vitamins C and E on any ischemia outcome. Flow-mediated dilation studies indicated no meaningful changes.

Conclusions— Intensive lipid lowering with atorvastatin to an LDL level of 80 mg/dL, with or without antioxidant vitamins, does not provide any further benefits in ambulatory ischemia, exercise time to onset of ischemia, and angina frequency than moderate lipid lowering with diet and low-dose lovastatin to an LDL level of <120 mg/dL.

Progesterone abolishes estrogen and/or atorvastatin endothelium dependent vasodilatory effects

This double blind randomized placebo controlled study assessed the effects of atorvastatin, estradiol and norethisterone, isolated and in combination, on the lipid profile and on vascular reactivity, in post-menopausal women with hypercholesterolemia and arterial hypertension. Ninety-four women aged 50-65 were selected. All have received dietary counseling (4 weeks), placebo (4 weeks), and drug therapy (12 weeks): 17-beta estradiol 2mg/day (E) (n=17); E + norethisterone acetate 1mg/day (P) (n=18); Atorvastatin 10mg/day (A) (n=20); E + A (n=21) and E + P + A (n=18). All treatment modalities have significantly reduced total cholesterol (TC) (E=8.8%, E + P=10.1%, A=27.9%, A + E=29.4% and E + P + A=35.7%) and LDL-cholesterol (LDL-c) levels (E + P + A=46.6%, E + A=45.9%, A=40.2%, E=20.3%, and E + P=12.1%). As concerns HDL-cholesterol (HDL-c), Groups E and E + A had increases of 15.5% and 13.1%, respectively. The addition of a progesterone compound reduced its concentration (Group E + P=-9.1%, and Group E + P + A=-9.5%). By random, approximately half of the patients in each group were designated to the endothelial function evaluation (brachial artery ultrasound). We observed that in Group A (n=10), in Group E (n=10) and with the association (Group E + A) (n=7), there was a significant increase in the flow-mediated vasodilatation as compared to basal measurements. The addition of a progestin has annulled these benefits.

CONCLUSIONS

Atorvastatin has promoted more beneficial effects on TC and LDL-c, whereas estradiol was responsible for an increase in HDL-c. The addition of a progesterone derivative abolished these benefits. Atorvastatin, estradiol or both together improved endothelial function, an effect suppressed by the addition of norethisterone.

Lipid-independent effects of statins on endothelial function and bioavailability of nitric oxide in hypercholesterolemic patients

BACKGROUND

Experimental evidence suggests a lipid-independent effect of statins on endothelial function and nitric oxide (NO) availability in humans. We investigated whether improvement in NO availability in hypercholesterolemia can be achieved rapidly with statins before lipid-lowering therapy is complete.

METHODS

We studied 41 patients (52 +/- 11 years) with low-density lipoprotein (LDL) cholesterol > or = 130 mg/dL (179 +/- 45 mg/dL) randomly assigned to treatment either with atorvastatin (20 mg/day) or cerivastatin (0.4 mg/day). Endothelium-dependent vasodilation of the forearm vasculature was measured by plethysmography and intra-arterial infusion of acetylcholine (ACh) after 3 days (n = 18) and 14 days (n = 39) of treatment. NO availability and oxidative stress were assessed by coinfusion of l-NMMA and vitamin C.

RESULTS

After 3 days of treatment, LDL-cholesterol decreased by 11.9% with a further decrease to 29.6% after 14 days ( P < .001). Endothelium-dependent vasodilation improved by +46.7% after 3 days of statin therapy compared with before therapy (ACh 48 microg/min: +15.7 +/- 10.6 vs +10.7 +/- 10.8 mL/min per 100 mL, P < .05). No further improvement in endothelium-dependent vasodilation (+42.7% compared with before therapy) could be demonstrated after 14 days of treatment (ACh 48 microg/min: +17.7 +/- 10.3 vs +12.4 +/- 9.3 mL/min per 100 mL before therapy, P < .001). Coinfusion of ACh plus vitamin C was able to improve endothelium-dependent vasodilation before but not after 3 or 14 days of statin therapy either. The improvement in endothelium-dependent vasodilation after therapy was no longer observed when the NO-synthase inhibitor l-NMMA was coinfused together with ACh.

CONCLUSIONS

Short-term lipid-lowering therapy with statins is able to improve endothelial function and NO availability almost completely after 3 days in hypercholesterolemic patients probably by decreasing oxidative stress. This improvement seems to be more rapid than the accompanying decline in LDL-cholesterol and not related to these lipid changes. This finding can support the concept of lipid-independent effects of statins in humans.

Effects of atorvastatin on reactive hyperemia and inflammatory process in patients with congestive heart failure

Purpose of the study was to investigate whether short-term atorvastatin treatment improves endothelial function and affects inflammatory process in patients with heart failure (HF) and normal cholesterol levels. HF is characterized by endothelial dysfunction and increased inflammatory process, while statins restore endothelial function having also anti-inflammatory effects in hypercholesterolemic patients. We investigated the effect of 4-week atorvastatin treatment (10 mg/day) on endothelial function and inflammatory markers in patients with HF and cholesterol levels <220 mg/dl. Patients were randomly allocated into groups and received atorvastatin (n=19) or no statin (n=19). Forearm blood flow was measured using gauge-strain plethysmography. Serum levels of tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), and soluble vascular cell adhesion molecule (sVCAM-1) were determined with ELISA. Data are expressed as median [25th-75th percentile]. Forearm vasodilatory response to reactive hyperemia was significantly improved in atorvastatin-treated patients (from 38.1% [32.0-59.1] to 70.0% [61.1-106.3], P<0.01), while it remained unaffected in the control group. Levels of IL-6, TNF-alpha and sVCAM-1 were decreased in atorvastatin-treated group (from 7.8 pg/ml [4.8-9.5], 3.2 pg/ml [2.7-4.8] and 595 ng/ml [440-810] to 5.6 pg/ml [2.5-9.0], 2.8 pg/ml [2.0-3.6] and 289 ng/ml [169-368], respectively, P<0.05 for all) but not in the control group. These findings indicate that atorvastatin may improve forearm vasodilatory response to reactive hyperemia and depress inflammatory process in patients with heart failure and normal baseline cholesterol levels.

Aging with cardiopulmonary disease: the rehab perspective

Cardiac disease is a leading cause of disability. This article reviews the epidemiology, pathophysiology, and risk factors for coronary heart disease. We explore the latest research in risk stratification, exercise training, and screening for cardiac rehabilitation in the elderly patient. The rehabilitation specialist will see how this select population differs in their medical and rehabilitative needs.

Endothelial function and dysfunction. Part II: Association with cardiovascular risk factors and diseases. A statement by the Working Group on Endothelins and Endothelial Factors of the European Society of Hypertension*

Dysfunction of the vascular endothelium is a hallmark of most conditions that are associated with atherosclerosis and is therefore held to be an early feature in atherogenesis. However, the mechanisms by which endothelial dysfunction occurs in smoking, dyslipidaemia, hyperhomocysteinaemia, diabetes mellitus, arterial hypertension, cerebrovascular diseases, coronary artery disease and heart failure are complex and heterogeneous. Recent data indicate that endothelial dysfunction is often associated with erectile dysfunction, which can precede and predict cardiovascular disease in men. This paper will provide a concise overview of the mechanisms causing endothelial dysfunction in the different cardiovascular risk factors and disease conditions, and of the impact of the intervention measures and treatments.

Effects of xuezhikang, an extract of cholestin, on lipid profile and C-reactive protein: a short-term time course study in patients with stable angina

BACKGROUND

Reduction of cholesterol and inflammation can be achieved by administration of a statin. Xuezhikang, an extract of cholestin, available from Chinese red yeast rice, could effectively modify the lipid profile. However, limited information is available regarding rapid effects of Xuezhikang on plasma C-reactive protein (CRP) and the lipid profile in patients with stable angina. We evaluated the short-term time course effects of lipid profile and CRP by Xuezhikang in patients with stable angina.

METHODS

Forty-eight consecutive patients with stable angina were randomly assigned to 1200 or 2400 mg/day of Xuezhikang. Blood samples were drawn at days 0, 1, 7 and 14 for lipid profile and CRP levels in all patients, and hepatic enzymes were also evaluated at days 0 and 14.

RESULTS

Both doses of Xuezhikang induced significant reductions in median CRP levels and in mean CRP levels at day 1 (13.0% with 1200 and 16.6% with 2400 mg/day; 14.7% with 1200 and 18.4% with 2400 mg/day), and at day 7 (18.3% with 1200 and 20.2% with 2400 mg/day; 18.5% with 1200 and 22.6% with 2400 mg/day) as well as at day 14 (28.6% with 1200 and 30.4% with 2400 mg/day; 21.7% with 1200 and 24.8% with 2400 mg/day) compared with baseline without a dose-dependent effect but a time-dependent manner. In addition, no changes were found at days 1 and 7 regarding lipid profile. However, both doses of Xuezhikang induced significant reductions in total cholesterol (TC, 13% and 22%), and low-density lipoprotein (LDL) cholesterol (23% and 32%) compared with baseline at day 14. The higher dose of Xuezhikang (2400 mg/day) resulted in significantly greater reductions in TC and LDL cholesterol compared with 1200 mg/day group (p<0.05, p<0.01, respectively). A less significant reduction was observed in triglycerides (TG) level (13% and 23%) compared with TC and LDL cholesterol. There was no significant difference in mean high-density lipoprotein (HDL) cholesterol levels compared with baseline in both groups.

CONCLUSIONS

Xuezhikang resulted in rapid reduction of CRP within 24 h and lipid profile within 2 weeks, which may be clinically important for patients with coronary artery disease.

Statin use and risks of death or fatal rejection in the Heart Transplant Lipid Registry

Although small, randomized trials have shown that statin use is associated with decreased risks of mortality and severe rejection, no study has examined statin therapy as used in actual practice in large numbers of heart transplant recipients. We analyzed data from the Heart Transplant Lipid Registry (n = 12 centers). Patients were included if they underwent transplantation between 1995 and 1999, survived >/=30 days after transplantation, and had >/=30 days of Registry follow-up. Multivariable Cox regression models, with propensity scoring performed to adjust for nonrandom allocation of statin therapy, were performed to determine the association of statin therapy with death and fatal rejection. The study included 1,186 patients, with a mean follow-up of 580 +/- 469 days; 937 patients (79%) received statin therapy. Overall, 71 patients (6%) died and 40 (3.4%) had fatal rejection. The statin group had a lower frequency of death (4% vs 13.7%, p <0.0001) and fatal rejection (2.4% vs 7.2%, p = 0.0001). Using multivariable Cox regression, with propensity scoring included to adjust for likelihood of receiving statin therapy, statin use was the only factor associated with lower risk of death (hazard ratio 0.29, 95% confidence interval 0.13 to 0.67) and fatal rejection (hazard ratio 0.27, 95% confidence interval 0.09 to 0.78). This study represents the largest population of heart transplant recipients analyzed for the relation between statin therapy and clinical outcomes in actual practice. Statin therapy was significantly associated with lower risk of death and fatal rejection, benefits that were independent of lipid values.

Oral folic acid enhances endothelial function in patients with hypercholesterolaemia receiving statins

BACKGROUND

Folic acid therapy has been shown to improve endothelial function in patients with familial hypercholesterolaemia via a possible antioxidant mechanism. Data on the possible role of folic acid in hypercholesterolaemic patients receiving statins are lacking. In the present study we tested the hypothesis that folic acid supplementation improves endothelial function in patients with hypercholesterolaemia and treatment with statins.

METHODS

Thirty-four hypercholesterolaemic patients receiving statins participated in the study; all subjects underwent measurement of endothelium-dependent, flow-mediated dilatation of the brachial artery and subsequently randomized to receive 5 mg of the folic acid (n=17) or placebo (n=17) for 4 weeks. Flow-mediated dilatation of the brachial artery was repeated at the end of the 4-week period.

RESULTS

Folic acid and placebo groups were comparable regarding age, sex, smoking, hypertension, coronary artery disease, obesity, family history and blood lipids. Folic acid administration resulted in an improvement of flow-mediated dilatation (4.7+/-3.2% to 7.1+/-3.1%, P=0.02), whereas there was no improvement after placebo administration (5.7+/-3.8% to 5.6+/-2.2%, ns). No significant change in nitrate-induced, endothelium- independent dilatation was observed after folic acid or placebo (ns).

CONCLUSIONS

Oral administration of folic acid (5 mg) for 4 weeks improves endothelial function in patients with hypercholesterolaemia treated with statins, with possible beneficial effects on the prognosis of these patients.

Relaxant effects of pravastatin, atorvastatin and cerivastatin on isolated rat aortic rings

Increasing evidence suggests that statins may have pleiotropic effects on vascular wall independent of their cholesterol lowering properties. In the present study, we investigated the acute vascular effects of pravastatin, atorvastatin and cerivastatin on rat isolated aortic rings. Statins effectively and comparably relaxed the aortic rings precontracted submaximally with noradrenaline, in a concentration-dependent manner, in which a high potency was observed with cerivastatin. Endothelium removal or incubation of the aortic rings with nitric oxide synthase inhibitor L-NOARG (10(-4) M) and/or cyclooxygenase inhibitor indomethacin (10(-5) M) significantly attenuated the acute vasorelaxation induced by either of statin. Additionally, different from the other two statins, a significant reduction was observed in response to cerivastatin in the presence of KATP channel inhibitor, glibenclamide (10(-5) M) and Na+- K+ ATPase inhibitor, ouabain (10(-4) M). Furthermore, pretreatment of the rings with the cholesterol precursor mevalonate (10(-3) M) significantly inhibited the endothelium-mediated relaxant effects of the statins. Our findings suggest that statins could acutely modulate vascular tone importantly by endothelium-dependent and mevalonate-related pathways.

What causes acute coronary syndromes? Applying Koch's postulates

The term "acute coronary syndromes" (ACS) is used to describe a heterogeneous spectrum of clinical conditions. This includes myocardial infarction, non-ST-elevation myocardial infarction, and unstable angina. These conditions are linked by a similar constellation of signs and symptoms but not necessarily by a common pathophysiology. They are syndromes. Several different hypotheses exist that have attempted to explain the pathological mechanisms that are involved in these conditions, however, it is not clear whether ACS are caused by variations of a single disease process or by several disease processes. The contribution of both vessel wall- and blood-related factors in the pathogenesis of acute coronary syndromes is herein discussed with the guidance of Koch's postulates.

Simvastatin acutely reduces myocardial reperfusion injury in vivo by activating the phosphatidylinositide 3-kinase/Akt pathway

Long-term pretreatment with statins reduces myocardial injury after acute ischemia and reperfusion by increasing the expression of endothelial nitric oxide synthase (eNOS). We hypothesized that statins may act rapidly enough to protect the myocardium from ischemia/reperfusion injury when given right at the beginning of the reperfusion period and tried to delineate the role of PI 3-kinase/Akt pathway in early eNOS activation. Activated simvastatin was given intravenously 3 minutes before starting the reperfusion after temporary coronary artery occlusion (CAO) in anaesthetized rats. Simvastatin significantly increased myocardial PI 3-kinase activity, AktSer473, and eNOSSer1177 phosphorylation and reduced infarct size by 42%. Infarct size reduction as well as activation of PI 3-kinase/Akt/eNOS pathway were not observed in rats co-treated with the PI 3-kinase inhibitor wortmannin. Contribution of eNOS was further delineated using the NOS inhibitor L-NAME, which could completely block cardioprotection by the statin. In summary, simvastatin acutely reduces the extent of myocardial necrosis in normocholesterolemic rats in an NO- dependent manner by activating the PI 3-kinase/Akt pathway. This is the first study demonstrating short-term cardioprotective effects of simvastatin in an in vivo model of ischemia/reperfusion.

Decreased Heart Rate Recovery in Patients With Heart Failure Effect of Fluvastatin Therapy

Heart rate recovery is the difference in heart rate at peak exercise and at a specific time interval following the onset of recovery. Attenuated heart rate recovery is an independent predictor of mortality in patients with a history of coronary artery disease. The aim of the present study was to evaluate the effect of a statin on heart rate recovery, particularly in patients with ischemic heart failure and hyperlipidemia. Twenty-nine consecutive hyperlipidemic, stable coronary artery disease patients with heart failure and 19 healthy subjects were enrolled. Heart rate recovery values at the 1st and 3rd minutes and lipid profiles of the patients were evaluated at baseline and following 3 months of treatment with fluvastatin. Compared with healthy subjects, the heart rate recovery values were significantly lower in the heart failure patients in both the 1st and 3rd minutes, respectively (31 +/- 6 versus 19 +/- 7, P < 0.0001; 66 +/- 7 versus 47 +/- 8, P < 0.0001). Heart rate recovery in the 1st and 3rd minutes increased from 19 +/- 7 to 24 +/- 9 and 47 +/- 8 to 57 +/- 11, respectively, following treatment (P < 0.001, P < 0.001). There were no significant correlations among the changes in lipid parameters or HRR in the first and third minutes in the recovery period. The results revealed an improvement in heart rate recovery in heart failure patients by fluvastatin treatment. If this association can be confirmed by other studies, it would be interesting to perform further studies into the mechanism underlying this finding.

Statin, like aspirin, should be given as early as possible in patients with acute coronary syndrome

It is estimated that about 1 million patients are hospitalized for acute coronary events each years in the United States. An acceptable theory is that the acute coronary syndrome is caused by rupture of the atherosclerotic plaque with superimposed thrombus, which is a complex process and involving a number of different stages. Previous studies indicated that inflammation is one of the most important features of vulnerable plaque, and occurs in most vulnerable plaque, comprised of monocytes, macrophages, and lymphocytes in both the cap and in the adventitia. This is supported by evidence that reduction in serum inflammatory marker levels, such as C-reactive protein, significantly decreased coronary events in patients with acute coronary syndrome. A large number of investigations have demonstrated that administration of statin could modify C-reactive protein concentrations with a concurrent fall in cardiovascular events. Our recent data indicated that reduction of inflammatory markers could be achieved within 24 h following a single dose of statin administration after admission in patients with coronary artery disease. Based on the available evidence and in light of the new understanding that statins have pleiotropic effects, especially as a potent anti-inflammatory agent, the statins, like aspirin, should be clinically given as early as possible in patients with acute coronary syndrome.

Protection of endothelial function

The vascular endothelium synthesizes and releases a spectrum of vasoactive substances and therefore plays a fundamental role in the basal and dynamic regulation of the circulation. Nitric oxide (NO)--originally described as endothelium-derived relaxing factor--is released from endothelial cells in response to shear stress produced by blood flow, and in response to activation of a variety of receptors. After diffusion from endothelial to vascular smooth muscle cells, NO increases intracellular cyclic guanosine-monophosphat concentrations by activation of the enzyme guanylate cyclase leading to relaxation of the smooth muscle cells. NO has also antithrombogenic, antiproliferative, leukocyte-adhesion inhibiting effects, and influences myocardial contractility. Endothelium-derived NO-mediated vascular relaxation is impaired in spontaneously hypertensive animals. NO decomposition by free oxygen radicals is a major mechanism of impaired NO bioavailability. The resulting imbalance of endothelium-derived relaxing and contracting substances disturbs the nor- mal function of the vascular endothelium. Endothelin acts as the natural counterpart to endothelium-derived NO. In man, besides its effect of increasing arterial blood pressure, ET-1 induces vascular and myocardial hypertrophy, which are independent risk factors for cardiovascular morbidity and mortality. Current therapeutic strategies concentrate mainly on lowering of low-density lipoprotein cholesterol and an impressive reduction in the risk for cardiovascular morbidity and mortality has been achieved. Inflammatory mechanisms play an important role in vascular disease and inflammatory plasma markers correlate with prognosis. Novel therapeutic strategies specifically targeting inflammation thus bear great potential for the prevention and treatment of atherosclerotic vascular disease.

Mechanisms, Significance and Treatment of Vascular Dysfunction in Type 2 Diabetes Mellitus

Endothelial dysfunction and increased arterial stiffness occur early in the pathogenesis of diabetic vasculopathy. They are both powerful independent predictors of cardiovascular risk. Advances in non-invasive methodologies have led to widespread clinical investigation of these abnormalities in diabetes mellitus, generating a wealth of new knowledge concerning the mechanisms of vascular dysfunction, risk factor associations and potential treatment targets. Endothelial dysfunction primarily reflects decreased availability of nitric oxide (NO), a critical endothelium-derived vasoactive factor with vasodilatory and anti-atherosclerotic properties. Techniques for assessing endothelial dysfunction include ultrasonographic measurement of flow-mediated vasodilatation of the brachial artery and plethysmography measurement of forearm blood flow responses to vasoactive agents. Arterial stiffness may be assessed using pulse wave analysis to generate measures of pulse wave velocity, arterial compliance and wave reflection. The pathogenesis of endothelial dysfunction in type 2 diabetes is multifactorial, with principal contributors being oxidative stress, dyslipidaemia and hyperglycaemia. Elevated blood glucose levels drive production of reactive oxidant species (ROS) via multiple pathways, resulting in uncoupling of mitochondrial oxidative phosphorylation and endothelial NO synthase (eNOS) activity, reducing NO availability and generating further ROS. Hyperglycaemia also contributes to accelerated arterial stiffening by increasing formation of advanced glycation end-products (AGEs), which alter vessel wall structure and function. Diabetic dyslipidaemia is characterised by accumulation of triglyceride-rich lipoproteins, small dense low-density lipoprotein (LDL) particles, reduced high-density lipoprotein (HDL)-cholesterol and increased postprandial free fatty acid flux. These lipid abnormalities contribute to increasing oxidative stress and may directly inhibit eNOS activity. Although lipid-regulating agents such as HMG-CoA reductase inhibitors (statins), fibric acid derivatives (fibrates) and fish oils are used to treat diabetic dyslipidaemia, their impact on vascular function is less clear. Studies in type 2 diabetes have yielded inconsistent results, but this may reflect sampling variation and the potential over-riding influence of oxidative stress, dysglycaemia and insulin resistance on endothelial dysfunction. Results of positive intervention trials suggest that improvement in vascular function is mediated by both lipid and non-lipid mechanisms, including anti-inflammatory, anti-oxidative and direct effects on the arterial wall. Other treatments, such as renin-angiotensin-aldosterone system antagonists, insulin sensitisers and lifestyle-based interventions, have shown beneficial effects on vascular function in type 2 diabetes. Novel approaches, targeting eNOS and AGEs, are under development, as are new lipid-regulating therapies that more effectively lower LDL-cholesterol and raise HDL-cholesterol. Combination therapy may potentially increase therapeutic efficacy and permit use of lower doses, thereby reducing the risk of adverse drug effects and interactions. Concomitant treatments that specifically target oxidative stress may also improve endothelial dysfunction in diabetes. Vascular function studies can be used to explore the therapeutic potential and mechanisms of action of new and established interventions, and provide useful surrogate measures for cardiovascular endpoints in clinical trials.

Ten-year Follow-up of Familial Hypercholesterolemia Patients After Intensive Cholesterol-lowering Therapy

To prevent coronary artery disease, it is necessary for patients with familial hyper-cholesterolemia (FH) to maintain a low cholesterol level. Recently a combination therapy of low-density lipoprotein (LDL) apheresis and statins has been used for FH patients, but their long-term prognosis over 10 years is unknown. In this single center prospective report, 18 FH patients with severe coronary stenosis received LDL apheresis every 2 or 4 weeks and statin therapy for 9.8 +/- 3.0 years. Probucol was given to 17 of the 18 patients. We observed their clinical events as well as coronary stenosis findings and ejection fractions for 10.7 +/- 2.6 years. Total and LDL cholesterol levels before therapy were 345 +/- 46 and 277 +/- 48 mg/dL, respectively. Immediately following LDL-apheresis, these levels decreased to 104 +/- 7.5 and 66 +/- 16 mg/dL, respectively. There were no cardiac deaths and 4 patients were free from any coronary events. There was one noncardiac death. Nonfatal myocardial in-farction occurred in 2 patients and coronary bypass surgery was required in one patient. Twelve patients received additional coronary angioplasty. There was little change in coronary stenosis and ejection fraction following 10 years of the combination therapy. Univariate Cox regression analysis revealed that the calculated mean LDL cholesterol level was the predictive value of treatment efficacy (mean LDL cholesterol < 140 mg/dL, hazard ratio 0.23, P = 0.028). The combination therapy of LDL-apheresis and antilipid drugs delayed the progression of coronary atherosclerosis and prevented a major cardiac event, although complete inhibition was limited to a small group. Additional coronary angioplasty is likely to be required for a favorable clinical outcome in FH patients.

Effects of atorvastatin on reactive hyperaemia and the thrombosis-fibrinolysis system in patients with heart failure

OBJECTIVE

To investigate the effects of short term atorvastatin treatment on forearm vasodilatory response to reactive hyperaemia (RH%) and on components of the thrombosis-fibrinolysis system (antithrombin III, proteins and S, factors V and VII, von Willebrand factor, tissue plasminogen activator (tPA), and plasminogen activator inhibitor (PAI-1)) in patients with heart failure.

PATIENTS AND METHODS

35 patients with heart failure were enrolled in this study; 17 patients received atorvastatin 10 mg/day and 18 patients received no statin for four weeks. Forearm blood flow (FBF) was measured by venous occlusion strain gauge plethysmography. RH% and forearm vasodilatory response to nitrate were defined as the percentage change of FBF from rest to the maximum flow during reactive hyperaemia and after nitrate administration, respectively. Plasma concentrations of antithrombin III, protein C, protein S, factor V, factor VII, von Willebrand factor, tPA, and PAI-1 were determined before and after treatment.

RESULTS

Maximum hyperaemic FBF remained unchanged in both groups. Baseline FBF was slightly but not significantly decreased in the atorvastatin treated group. RH% was significantly increased only in the atorvastatin treated group, from mean (SD) 42.44 (18.9)% to 83.7 (36.1)% (p < 0.01). Plasma concentrations of antithrombin III (from mean (SD) 81.7 (11.37)% to 73.5 (13.8)%), protein C (from mean (SD) 88.3 (26.9)% to 63.9 (25.0)%), factor V (from mean (SD) 126.2 (33.4)% to 94.9 (29.8)%), tPA (from median (25th-75th percentile) 11.68 (8.60-20.95) ng/ml to 10.30 (8.65-15.12) ng/ml), and PAI-1 (from median (25th-75th percentile) 3.10 (2.15-4.40) IU/l to 1.90 (0.75-3.0) IU/l) were significantly decreased in the atorvastatin treated group (p < 0.05) but not in the control group. Plasma concentrations of von Willebrand factor, factor VII, and protein S remained unaffected in both groups.

CONCLUSION

Atorvastatin did not change the maximum hyperaemic flow, although it decreased plasma concentrations of antithrombin III, protein C, factor V, tPA, and PAI-1 in patients with heart failure. Therefore, short term treatment with atorvastatin may affect the expression of both endothelium and liver derived components of the thrombosis-fibrinolysis system in patients with heart failure.

Effects of statins on vascular structure and function: a systematic review

PURPOSE

Statins reduce cardiovascular events by more than can be explained by their effects on lipids. We conducted a systematic review of how statins affect vascular structure and function, differences among statins, and correlations between the effects of statins on vascular outcomes and either lipid levels or cardiovascular outcomes.

METHODS

We primarily searched MEDLINE (1980 to March 2004) to identify all studies with at least 10 subjects that reported the effects of currently available statins on coronary artery stenosis, carotid intima-media thickness, and endothelial function (excluding studies of drug combinations and subjects with organ transplants). Meta-analyses were performed when feasible.

RESULTS

Statins decrease the progression and increase the regression of coronary artery lesions and luminal narrowing. Compared with placebo, statins decrease the likelihood of coronary artery restenosis (summary risk ratio = 0.85; 95% confidence interval: 0.77 to 0.95). Statins appear to slow the progression of carotid artery intima-media thickness. Although the effect of statins on coronary endothelial function is uncertain, statins appear to improve peripheral endothelial function. There is no conclusive evidence to suggest that individual statins differ in their effects on these outcomes. Studies generally found weak or no correlation between the effects of statins on vascular outcomes and lipid levels. No study showed a correlation between vascular effect and clinical outcome.

CONCLUSION

Statins slow the progression of, and may reverse, atherosclerosis. The magnitude of these effects, however, is small compared with the effects of statins on cardiovascular events. Statins also improve measures of vascular function, which may contribute to their clinical benefits. There is insufficient evidence to suggest that individual statins differ in their vascular effects.

Early effects of statins in patients with coronary artery disease and high C-reactive protein

Statins improve survival in patients with coronary artery disease, especially those with elevated C-reactive protein (CRP). Although some randomized studies have shown a delay in statin-related survival advantage of up to 2 years, recent studies demonstrated early (<2 months) survival benefit in certain patient groups. We hypothesized that this early benefit relates to baseline CRP concentration. Patients (n = 2,924) with significant, angiographically defined coronary artery disease (>/=70% stenosis in >/=1 coronary artery) were followed for an average of 2.4 years after discharged on a statin prescription. CRP was divided into tertiles (<1.2, 1.2 to 1.7, >1.7 mg/dl), and Kaplan-Meier methods were used to determine timing of statin benefit in both the overall population and a propensity score-matched subgroup. Cox regressions (multivariable and propensity score approaches) were used to predict mortality. Statins were prescribed for 28.4% of patients. In the first CRP tertile, no early statin benefit was observed (adjusted hazard ratio 0.69, 95% confidence interval [CI] 0.30 to 1.6, p = 0.39), and survival curves separated after >2 years. However, in the second and the third tertiles, statin survival curves separated much earlier ( approximately 3 months and 1 week, respectively) and statins predicted improved survival (second tertile: hazard ratio 0.63, 95% CI 0.32 to 1.2, p = 0.17; third tertile: hazard ratio 0.35, 95% CI 0.18 to 0.67, p = 0.002). Propensity score analysis confirmed both statin benefit and early timing. Thus, statin use in patients with high CRP provides not only a larger but also a significantly earlier absolute survival benefit than statin use in patients with lower CRP. This provides further evidence of an anti-inflammatory effect of statins.

Role of endothelial dysfunction in atherosclerosis

As the major regulator of vascular homeostasis, the endothelium exerts a number of vasoprotective effects, such as vasodilation, suppression of smooth muscle cell growth, and inhibition of inflammatory responses. Many of these effects are largely mediated by nitric oxide, the most potent endogenous vasodilator. Nitric oxide opposes the effects of endothelium-derived vasoconstrictors and inhibits oxidation of low-density lipoprotein. A defect in the production or activity of nitric oxide leads to endothelial dysfunction, signaled by impaired endothelium-dependent vasodilation. Accumulating evidence suggests that endothelial dysfunction is an early marker for atherosclerosis and can be detected before structural changes to the vessel wall are apparent on angiography or ultrasound. Many of the risk factors that predispose to atherosclerosis can also cause endothelial dysfunction, and the presence of multiple risk factors has been found to predict endothelial dysfunction. A number of clinical trials have shown that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) improve endothelial dysfunction in patients with coronary risk factors beyond what could be attributed to their impact on plasma lipids. Studies have elucidated several possible mechanisms by which statin therapy may improve endothelial dysfunction, including upregulation of nitric oxide production or activity and reduction of oxidative stress.

Assessing the prognostic value of coronary endothelial function in patients referred for a first coronary angiogram

At present, the value of endothelial function as a prognostic tool has been evaluated only in selected groups of patients with mild or minor coronary artery disease, not in the complete spectrum of patients presenting with angina. The objective of this study was to evaluate whether endothelium-dependent vasodilation of the coronary arteries in response to acetylcholine infusion as a marker of endothelial function would have prognostic value in patients referred for a first coronary angiogram. The data suggest that endothelial function assessment does not contribute to the prediction of outcomes in patients referred for a first coronary angiogram.

Cardioprotective and other emerging effects of statins

The lipid-lowering properties of statins are accompanied by a number of other cardioprotective effects. These 'pleiotropic' actions affect almost the entire process of atherogenesis, from initial endothelial injury to the moment of plaque rupture and thrombosis. This paper discusses the nonlipid-lowering effects of statins that affect the initiation, progression, regression and repair of atherosclerosis lesions, as well as factors that affect plaque instability. The emergent anti-inflammatory, antioxidant and immunomodulatory properties of statins are extensive and diverse. Many of these properties, which are independent of cholesterol synthesis inhibition, help to reduce the ischaemic burden on the cardiovascular system. In addition, the immunomodulatory properties of statins may provide new indications for these agents in the treatment of autoimmune diseases.

Atorvastatin enhances sildenafil-induced vasodilation through nitric oxide-mediated mechanisms

Statins have cholesterol-independent effects including an increased vascular nitric oxide (NO) activity and are commonly used by patients with cardiovascular disease. Such patients frequently have erectile dysfunction, which may be treated with sildenafil, a selective inhibitor of phosphodiesterase type 5. Since statins and sildenafil can activate the NO-cGMP pathway, we investigated whether pre-treatment with atorvastatin (0, 5 and 30 mg/kg/day) for 2 weeks affects sildenafil (1 pM-100 mM)-induced relaxation of aortic rings isolated from Wistar rats. We also examined the hemodynamic consequences of this interaction in Wistar rats. Plasma nitrite/nitrate (NOx) concentrations were determined using an ozone-based chemiluminescence assay. While pre-treatment with atorvastatin increased the potency of sildenafil-induced vasorelaxation (P<0.01), no differences were observed in the maximum sildenafil-induced relaxation. Pre-incubation of aortic rings with NG-nitro-L-arginine methyl ester (L-NAME) reversed atorvastatin-induced increase in the potency of sildenafil relaxation. In addition, pre-treatment with atorvastatin enhanced plasma NOx concentrations and sildenafil-induced hypotension and tachycardia (all P<0.05). These results suggest that atorvastatin increases the vascular sensitivity to sildenafil through NO-mediated mechanisms.

Coronary artery disease and prevention of heart failure

Coronary artery disease is a major contributor to the progression of left ventricular systolic dysfunction and heart failure (HF). Recognizing that coronary artery disease is a leading cause of HF in the United States is critical to reducing mortality resulting from this condition. Although some patients may be candidates for mechanical revascularization to improve left ventricular function, all patients are candidates for aggressive secondary prevention strategies. This review discusses the prevalence of coronary artery disease, prognostic significance and pathophysiology, risk factor modifications, pharmacologic treatments, and the role of revascularization.

Effects of multivitamins and low-dose folic acid supplements on flow-mediated vasodilation and plasma homocysteine levels in older adults

BACKGROUND

Hyperhomocysteinemia is associated with aging, endothelial dysfunction, and increased risk of coronary heart disease in older adults; however, the effects of homocysteine-lowering therapy on vascular reactivity in older persons are unknown. The objective of this study was to determine the effects of multivitamins (MV) and folic acid (FA) supplements on flow-mediated vasodilation (FMD) in older adults.

METHODS

Individuals > or =70 years old with homocysteine levels > or =10 micromol/L were recruited for this 40-week, prospective, single-blinded study. All subjects were treated sequentially, with each of the following daily therapies for 10 weeks: (1) placebo, (2) MV (400 microg FA, 6 mg vitamin B6, 25 microg vitamin B12), (3) placebo, then (4) MV + FA (total FA, 1400 microg). FMD, folate intake, and laboratory values were measured at each visit. Investigators were blinded to subject treatment phase when measuring vessel diameters and calculating FMD.

RESULTS

Twenty subjects (mean +/- SEM age, 78.0 +/- 1.2 [range, 70 to 88] years, 9 women) completed the MV and 17 completed the MV + FA interventions. FMD was impaired at baseline (2.0% +/- 1.2%). During the 40-week study, homocysteine levels decreased by 1.4 +/- 0.9 micromol/L (p(trend) = 0.034) from a baseline of 12.8 +/- 0.6 micromol/L; however, FMD did not change significantly (p(trend) = 0.874). FMD did not improve after therapy with MV alone (3.0% +/- 0.9% [week 10] vs 2.4% +/- 1.1% [week 20], P =.716) or with MV + FA (2.6% +/- 0.9% [week 30] vs 1.9% +/- 0.7% [week 40], P =.484).

CONCLUSIONS

At doses commonly prescribed in clinical practice, MV and FA supplements did not improve FMD in older adults with hyperhomocysteinemia.

The role of coronary endothelial function testing in patients suspected for angina pectoris

Coronary vasomotor function plays an important role in onset and progression of coronary artery disease. Suwaidi [Circulation 101 (2000) 948] and Schächinger [Circulation 101 (2000) 1899] demonstrated that vasomotor dysfunction has a significant impact on events in patients with minimal coronary artery disease. Endothelial specific testing can be performed in coronary as well as peripheral arteries. However, non-coronary tests have a low correlation with the coronary vasomotor response, as assessed by acetylcholine. In large clinical prospective placebo-controlled trials, angiotensin-converting enzyme (ACE) inhibitors and lipid-lowering drugs reduce morbidity and mortality after myocardial infarction or myocardial infarction-induced heart failure. The same drugs restore endothelial dysfunction after myocardial infarction, as was demonstrated in small experimental and clinical studies. Recent studies in patients with coronary artery disease showed a relation with endothelial dysfunction and the occurrence of adverse coronary events. For this reason, it is important to develop methods to evaluate endothelial function.

Effects of statin therapy on vascular dysfunction

Dyslipidemia and vascular inflammation play critical roles in the onset of acute coronary syndromes including myocardial infarction. Recent advances in cardiovascular medicine demonstrate that lipid-lowering therapy by 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) prevents acute coronary complications, probably by limiting inflammation in atheroma. Although a number of studies have suggested various effects of statins on vascular dysfunction independent of lipid lowering, the clinical benefits of such effects are not established as yet.

Does aggressive statin therapy offer improved cholesterol-independent benefits compared to conventional statin treatment?

There is currently intense research interest in the properties of HMG-CoA reductase inhibitors (statins) beyond their well-documented lipid-lowering action. Studies have consistently demonstrated that administration of statin therapy decreases levels of the inflammatory marker C-reactive protein (CRP), a marker associated with an increased risk of cardiovascular events. This effect appears to be independent of the extent of reduction in total or LDL-cholesterol. Statins also appear to improve endothelial dysfunction by increasing endothelium-dependent vasodilatation. There is also evidence that statins inhibit fibrin formation and thrombus development, an effect that which would be clinically beneficial following plaque fissure or rupture. Early preclinical and clinical evidence suggests that there are quantitative differences between statin regimens in terms of their cholesterol-independent properties. Trials comparing equipotent doses of different statins, based on lipid-lowering efficacy, have not reported any differences in cholesterol-independent properties. However, the current evidence base indicates that more aggressive statin regimens are associated with an enhanced anti-inflammatory effect. Intensive lipid-lowering using statin therapy generates a greater reduction in mortality than standard lipid management, and it is possible that enhanced cholesterol-independent effects may account for some of this excess benefit.

Effects of statins on endothelium and their contribution to neovascularization by mobilization of endothelial progenitor cells

Statins are potent drugs with a variety of cardiovascular protective effects which appear to occur independent of cholesterol reduction. The vasculoprotective effects of statins might be due to their direct effect on endothelial cells leading to improved nitric oxide (NO) bioavailability. Mechanistically, statins induce endothelial nitric oxide synthesis (eNOS) mRNA stability in endothelial cells and promote eNOS activity through a PI3K/Akt dependent pathway. Novel targets of statins are pro-angiogenic actions including the mobilization and differentiation of bone marrow derived endothelial progenitor cells, which accelerate angiogenesis or re-endothelialization. The functional improvement and increased homing capacity of endothelial progenitor cells induced by statin treatment might reverse impaired functional regeneration capacities seen in patients with risk factors for coronary artery disease or documented active coronary artery disease.

Statin drugs do not affect serum complement activation in vitro

Statin drugs prevent coronary heart disease through anti-inflammatory mechanisms in addition to the well-known reduction of low-density lipoproteins. The complement system plays an essential role in the inflammatory response and has been postulated to be modified by statins. A direct role for statins in complement activation, however, has not been previously investigated. We therefore studied the effect of statins on in vitro complement activation. Pravastatin, atorvastatin and the active metabolite of the latter, ortho-hydroxy atorvastatin, were added to normal human serum and incubated for 1 h in the absence or presence of aggregated immunoglobulin (classical pathway activation) or cobra venom factor (alternative pathway activation). The degree of complement activation, as detected by specific complement-activation products for the classical pathway (C1rs-C1-inhibitor complexes), the combined classical and lectin pathway (C4bc), the alternative pathway (C3bBbP) and the final common pathway (C3bc and TCC), was not affected by pre-incubation of the serum with any of the statins. Statins do not affect complement activation directly, but indirect effects in vivo may well be operative.

Beyond the laboratory: clinical implications for statin pleiotropy

Results from large-scale clinical trials of lipid lowering with 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) have led to a revolution in the management of atherosclerosis. In addition to their potent effect on serum lipid levels, statins influence several other cellular pathways, including those involving inflammatory, oxidative, and thrombotic processes. These effects clearly have the potential to beneficially modify the atherogenic process, and it has been suggested that they contribute to the impressive results seen in the clinical trials. We review the clinical evidence for benefits of statin therapy that are distinct from their effect on lipid biology. In particular, we address three key issues: the role of statins in diseases not traditionally associated with elevated cholesterol levels; whether clinical benefits are seen with statin therapy before an effect on lipid levels; and whether the magnitude of clinical benefit observed with statin therapy is unrelated to the degree of cholesterol reduction. At present, low-density-lipoprotein lowering seems to be the primary mechanism underlying the clinical benefits of statin therapy and should remain the focus of risk-reduction strategies in clinical practice.