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.     

Debate: "How low should LDL cholesterol be lowered?" Viewpoint: "It doesn't need to be very low"

The importance of low-density lipoprotein (LDL) control in the management of patients at high risk of cardiovascular events is unquestionable. The major statin trials have shown that the benefits of LDL lowering extend throughout the range of risk and the range of serum cholesterol, and have indicated that the protective effects of the intervention are mostly related to the baseline risk. Statin therapy is, for this reason, currently seen as an anti-atherogenic approach for the majority of high risk individuals and possibly all coronary heart disease patients. This debate is not about the value of statin therapy or the importance of LDL reduction, but about the goals to be set once we decide that LDL cholesterol must be reduced. With the National Cholesterol Education Program (NCEP) guidelines representing a solid middle ground, the two viewpoints in this debate try to argue, on one hand, that the LDL goals should be substantially lower than our current standards or, on the other, that a specific on-treatment LDL value may not be the most important goal to pursue. We defend the latter position by presenting the case that the most effective LDL intervention in high risk patients is to achieve a reduction of at least 30%. This strategy complies with the NCEP guidelines, as most of the high risk patients treated with an average dose of an average statin would experience a 30-40% LDL reduction that would put on-treatment LDL levels safely below goal. Our position differs from both the guidelines and the proponents of more aggressive LDL goals in the management of the two extremes of the cholesterol distribution, where our lack of interest in a predefined on-treatment LDL concentration would make us more aggressive than guidelines on low baseline LDL patients and less aggressive than guidelines on high baseline LDL patients.     

Cardiovascular outcomes among participants with diabetes in the recent large statin trials

PURPOSE OF REVIEW: Despite their increased cardiovascular risk and its continuous relationship with cholesterol, until recently only diabetic patients with marked dyslipidaemia were routinely offered lipid-lowering therapy. The secondary prevention statin trials led to more widespread cholesterol lowering in patients with coronary disease and diabetes. Here we review the results of recent randomized trials, which included substantial numbers of patients with diabetes and no vascular disease. RECENT FINDINGS: The MRC/BHF Heart Protection Study included 5963 participants with diabetes, of whom 2912 had no history of vascular disease at baseline. Patients were randomized to 40 mg simvastatin daily or matching placebo for 5 years, which, on average, reduced LDL by 1.0 mmol/l compared with placebo. Highly significant reductions of about one-quarter in major vascular events were seen both overall and in different types of patient with diabetes, including those with average and below average lipid levels. Recent data from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial and the Anglo-Scandinavian Cardiac Outcomes Trial support these findings and are consistent with these effects. SUMMARY: Good quality, randomized trials including substantial numbers of patients with diabetes show that such patients obtain the same proportional benefit as other groups studied. Given their increased cardiovascular risk, these findings argue for a simple strategy of considering routine statin therapy for patients with type 2 diabetes and adult patients with type 1 diabetes, irrespective of lipid levels. As generic statins become available this could have a greater impact on the burden of cardiovascular disease in diabetes than restricted and targeted therapy.     

Cardiovascular disease with diabetes or the metabolic syndrome: should statins or fibrates be first line lipid therapy?

PURPOSE OF REVIEW: Subgroups with diabetes or with features of the metabolic syndrome have been increasingly highlighted in large clinical endpoint trials with lipid therapy. This review will focus on the results of trials with statins or fibrates and examine the strength of the evidence for major cardiovascular event reduction with each kind of therapy in these high-risk subgroups that typically have low-to-moderate levels of LDL cholesterol. RECENT FINDINGS: Of six statin trials in populations with moderately increased LDL cholesterol only one, the Heart Protection Study, has shown that statin therapy will significantly reduce the major coronary heart disease events of non-fatal myocardial infarction or coronary heart disease death in diabetes. None of these trials has shown that statins have a particular predilection for reducing cardiovascular events in individuals with higher levels of body weight or other features of the metabolic syndrome. There are far fewer trial data with fibrates than with statins. However, the Veterans Affairs High Density Lipoprotein Intervention Trial has shown that a fibrate can significantly reduce major cardiovascular events, most particularly coronary heart disease death, in those with diabetes as well as those without diabetes who have insulin resistance. Indeed, all fibrate trials show that this therapy appears to selectively benefit the individual with obesity and features of the metabolic syndrome. SUMMARY: Based principally on evidence from the Veterans Affairs High Density Lipoprotein Intervention Trial and the cumulative experience with statins, trial data would thus far suggest that the patient with a modest increase in LDL cholesterol who has diabetes or features of the metabolic syndrome might be likely to achieve more substantial cardiovascular benefit from fibrate than from statin therapy.     

The efficacy and safety of intensive statin therapy: a meta-analysis of randomized trials

Background

Recent lipid guidelines recommend aggressive low-density lipoprotein (LDL) cholesterol lowering in patients with coronary artery disease. To clarify the evidence for this recommendation, we conducted a meta-analysis of randomized controlled trials that compared different intensities of statin therapy.

Methods

We searched electronic databases (MEDLINE, EMBASE, Cochrane Central Registery of Controlled Trials, Web of Science) for randomized controlled trials published up to July 19, 2007, that compared statin regimens of different intensities in adults with coronary artery disease and that reported cardiovascular events or mortality. Data were pooled using random-effects models to calculate odds ratios (OR).

Results

A total of 7 trials (29 395 patients) were included. Compared with less intensive statin regimens, more intensive regimens further reduced LDL levels (0.72 mmol/L reduction, 95% confidence interval [CI] 0.60–0.84 mmol/L), and reduced the risk of myocardial infarction (OR 0.83, 95% CI 0.77–0.91) and stroke (OR 0.82, 95% CI 0.71–0.95). Although there was no effect on mortality among patients with chronic coronary artery disease (OR 0.96, 95% CI 0.80–1.14), all-cause mortality was reduced among patients with acute coronary syndromes treated with more intensive statin regimens (OR 0.75, 95% CI 0.61–0.93). Compared with lower intensity regimens, more intensive regimens were associated with small absolute increases in rates of drug discontinuation (2.5%), elevated levels of aminotransferases (1%) and myopathy (0.5%), and there was no difference in noncardiovascular mortality. All 7 trials reported events by randomization arm rather than by LDL level achieved. About half of the patients treated with more intensive statin therapy did not achieve an LDL level of less than 2.0 mmol/L, and none of the trials tested combination therapies.

Interpretation

Our analysis supports the use of more intensive statin regimens in patients with established coronary artery disease. There is insufficient evidence to advocate treating to particular LDL targets, using combination lipid-lowering therapy to achieve these targets or for using more intensive regimens in patients without established coronary artery disease.Dyslipidemia is the most important modifiable risk factor for myocardial infarction worldwide,¹ and serum cholesterol levels are directly related to mortality from coronary artery disease in all populations studied.^2–4 Over the past decade, randomized controlled trials enrolling a wide variety of patients have confirmed that for every 1-mmol/L reduction in serum low-density lipoprotein (LDL) cholesterol achieved by statin therapy, the relative risks of cardiovascular events and mortality are reduced (by 21% and 12% respectively).⁵Statins exert their beneficial effects primarily by reducing the level of LDL cholesterol,⁶ and the reductions in the relative risk of cardiovascular events achieved by statin therapy appears to be similar regardless of baseline cholesterol levels.⁵ As a result, attention has increasingly focused on defining optimal target LDL levels, particularly in patients at highest risk (i.e., those with coronary artery disease). Based on the observational studies mentioned above,^2,3 the apparent lack of a lower threshold for statin benefit in the randomized controlled trials, and recent trials reporting greater benefits with more intensive statin regimens (compared with less intensive regimens), Canadian⁷ and American⁸ guidelines for secondary prevention now recommend target LDL levels below 2.0 mmol/L in patients with coronary artery disease. On the other hand, European guidelines specify a target LDL of 2.5 mmol/L in these patients.⁹ Questions have been raised about the safety and incremental benefits of more intensive statin regimens.^10–12We performed a systematic review and meta-analysis to critically examine the evidence for the safety, efficacy (LDL lowering) and clinical effectiveness from trials comparing more intensive statin therapy with less intensive statin therapy in patients with coronary artery disease.     

Protecting the heart: a practical review of the statin studies

The aim of this review of the landmark HMG-CoA reductase inhibitors (statins) studies is to enable the clinician to draw practical lessons from these trials. The Scandinavian Simvastatin Survival Study (4S) established the importance of treating the hypercholesterolemic patient with established cardiovascular heart disease. The West of Scotland Coronary Prevention Study (WOSCOPS) showed the benefit of treating healthy hypercholesterolemic men who were nevertheless at high risk of developing cardiovascular heart disease in the future. The Cholesterol and Recurrent Events (CARE) study, a secondary prevention trial, proved the benefit of treating patients with myocardial ischemia and cholesterol levels within normal limits. This conclusion was confirmed by the Long-term Intervention With Pravastatin in Ischemic Disease (LIPID) study, another secondary prevention study that enrolled patients with a wide range of cholesterol levels (4-7 mmol/dL), into which the large majority of patients would belong. The importance of treating patients with established ischemic heart disease (IHD), and those at high risk of developing cardiovascular heart disease, regardless of cholesterol level, was being realized. The Air Force/Texas Coronary Artery Prevention Study (AFCAPS/TexCAPS) then showed that treatment can reduce adverse cardiovascular events even in the primary prevention of patients with normal cholesterol levels. The Myocardial Ischemia Reduction With Aggressive Cholesterol Lowering (MIRACL) trial showed that hypocholesterolemic therapy is useful in the setting of an acute coronary syndrome, while the Atorvastatin Versus Revascularisation Treatment (AVERT) study showed that aggressive statin therapy is as good as angioplasty in reducing ischemic cardiac events in patients with stable angina pectoris. Finally, the Heart Protection Study (HPS) randomized more than 20,000 patients, and the value of statins in reducing adverse cardiovascular events in the high-risk patient, including the elderly, women, and even in those with low cholesterol levels, is beyond doubt. The emphasis is now on the risk level for developing cardiovascular events, and treatment should target the high-risk group and not be dependent on the actual cholesterol level of the patient. It is interesting to compare the large amount of data on the value and safety of the statins with the much more limited and less convincing data on antioxidant vitamins.     

Quantifying effect of statins on low density lipoprotein cholesterol, ischaemic heart disease,and stroke: systematic review and meta-analysis

Objectives To determine by how much statins reduce serum concentrations of low density lipoprotein (LDL) cholesterol and incidence of ischaemic heart disease (IHD) events and stroke, according to drug, dose, and duration of treatment.Design Three meta-analyses: 164 short term randomised placebo controlled trials of six statins and LDL cholesterol reduction; 58 randomised trials of cholesterol lowering by any means and IHD events; and nine cohort studies and the same 58 trials on stoke.Main outcome measures Reductions in LDL cholesterol according to statin and dose; reduction in IHD events and stroke for a specified reduction in LDL cholesterol.Results Reductions in LDL cholesterol (in the 164 trials) were 2.8 mmol/l (60%) with rosuvastatin 80 mg/day, 2.6 mmol/l (55%) with atorvastatin 80 mg/day, 1.8 mmol/l (40%) with atorvastatin 10 mg/day, lovastatin 40 mg/day, simvastatin 40 mg/day, or rosuvastatin 5 mg/day, all from pretreatment concentrations of 4.8 mmol/l. Pravastatin and fluvastatin achieved smaller reductions. In the 58 trials, for an LDL cholesterol reduction of 1.0 mmol/l the risk of IHD events was reduced by 11% in the first year of treatment, 24% in the second year, 33% in years three to five, and by 36% thereafter (P < 0.001 for trend). IHD events were reduced by 20%, 31%, and 51% in trials grouped by LDL cholesterol reduction (means 0.5 mmol/l, 1.0 mmol/l, and 1.6 mmol/l) after results from first two years of treatment were excluded (P < 0.001 for trend). After several years a reduction of 1.8 mmol/l would reduce IHD events by an estimated 61%. Results from the same 58 trials, corroborated by results from the nine cohort studies, show that lowering LDL cholesterol decreases all stroke by 10% for a 1 mmol/l reduction and 17% for a 1.8 mmol/l reduction. Estimates allow for the fact that trials tended to recruit people with vascular disease, among whom the effect of LDL cholesterol reduction on stroke is greater because of their higher risk of thromboembolic stroke (rather than haemorrhagic stroke) compared with people in the general population.Conclusions Statins can lower LDL cholesterol concentration by an average of 1.8 mmol/l which reduces the risk of IHD events by about 60% and stroke by 17%.     

Update for primary healthcare providers: recent statin trials and revised National Cholesterol Education Program III guidelines

Statins produce large, clinically important beneficial effects on total low-density lipoprotein (LDL) cholesterol and triglycerides while raising high-density lipoprotein (HDL) cholesterol--each of which increases the risks for cardiovascular disease (CVD). In randomized trials of secondary and primary prevention, and their meta-analyses, statins confer statistically significant, clinically important reductions in myocardial infarction, stroke, and CVD death. In 2001, the National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III included LDL as the primary target, recommending optional goals of < 100 mg/dL for high-risk patients, < 130 mg/dL for moderate-risk patients, and < 160 mg/dL for low-risk patients. We conducted a search of randomized trials of statins whose results were published since May 15, 2001. We extracted overall trial results and data on adverse events, when available. We reviewed 7 published trials of statins, some of which contributed to the recent addendum to the NCEP ATP III guidelines that recommend reducing LDL goals to < 70 for very high-risk and < 100 for moderately high-risk patients via statins. Data from these trials demonstrate that greater LDL reductions produce larger CVD benefits in various categories of high- and moderate-risk patients, including a large number of primary prevention patients with metabolic syndrome who should be treated as aggressively as patients who have survived a myocardial infarction or stroke. Together, these recent statin trials and the NCEP ATP III revised guidelines, if implemented by primary healthcare providers, would result in many more patients receiving statins of proven benefit and reassuring adverse event profile.     

Perspectives from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial--Lipid Lowering Trial and the Anglo-Scandinavian Cardiac Outcomes Trial--Lipid Lowering Arm

PURPOSE OF REVIEW: The design, process and outcomes are compared between two large clinical trials of LDL cholesterol reduction with statin treatment in patients with known high blood pressure. This new information is placed in the context of previous clinical trials of cholesterol reduction, which have provided analyses of sub-groups with high blood pressure. RECENT FINDINGS: The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial failed to find a significant reduction of total mortality (primary endpoint), cardiovascular mortality or major cardiovascular events. This differed sharply from the Anglo-Scandinavian Cardiac Outcomes Trial, Lipid Lowering Arm, which was stopped before the planned termination due to a marked reduction (36%) in coronary death or myocardial infarction (primary endpoint). This trial also found significant reductions in stroke (27%) and separately, all major vascular events (21%). The two studies were similar in that they each contained over 10 000 participants with documented high blood pressure requiring drug therapy and they both used a fixed dose of a single statin. Pravastatin (40 mg/day) was used in the former and atorvastatin 10 mg/day in the latter. The major difference was that the control group in the Anglo-Scandinavian trial was treated with placebo with a double blind design whereas antihypertensive and lipid-lowering trial was open label with controls receiving usual care. SUMMARY: The benefit of achieving and maintaining significant LDL cholesterol reduction in patients with high blood pressure was convincingly demonstrated in the Anglo-Scandinavian trial. The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial failed to achieve similar success due to use of a less effective drug and loss of the differential effect with increasing statin treatment in the usual care control group.     

A common KIF6 polymorphism increases vulnerability to low-density lipoprotein cholesterol: two meta-analyses and a meta-regression analysis

Background

We sought to determine if a common polymorphism can influence vulnerability to LDL cholesterol, and thereby influence the clinical benefit derived from therapies that reduce LDL cholesterol.

Methods

We conducted a meta-analysis of the association between a common Trp719Arg polymorphism in the kinesin-like protein 6 (KIF6) gene and the risk of cardiovascular disease (CVD), and a meta-regression analysis to measure the effect modification of this polymorphism on the association between LDL cholesterol and the risk of CVD. We used this measure of genetic effect modification to predict the expected difference in clinical benefit among KIF6 719Arg allele carriers and non-carriers in response to therapies that reduce LDL cholesterol. We then conducted a meta-analysis of statin trials to compare the expected difference in clinical benefit with the observed difference during treatment with a statin.

Results

In a meta-analysis involving 144,931 participants, the KIF6 719Arg allele was not associated with the relative risk (RR) of CVD (RR: 1.02, 95%CI: 0.98–1.07, p = 0.288). Meta-regression analysis involving 88,535 participants, however, showed that the 719Arg allele appears to influence the effect of LDL cholesterol on the risk of CVD. KIF6 carriers experienced a 13% greater reduction in the risk of CVD per mmol/L decrease in LDL cholesterol than non-carriers. We interpreted this difference as the expected difference in clinical benefit among KIF6 carriers and non-carriers in response to therapies that lower LDL cholesterol. The difference in clinical benefit predicted by the increased vulnerability to LDL cholesterol among KIF6 carriers (ratio of RR: 0.87, 95%CI: 0.80–0.94, p = 0.001) agreed very closely with the observed difference among 50,060 KIF6 carriers and non-carriers enrolled in 8 randomized trials of statin therapy (ratio of RR: 0.87, 95%CI: 0.77–0.99, p = 0.038).

Conclusion

The KIF6 719Arg allele increases vulnerability to LDL cholesterol and thereby influences the expected clinical benefit of therapies that reduce LDL cholesterol.     

ATP binding cassette transporter G5 and G8 genotypes and plasma lipoprotein levels before and after treatment with atorvastatin

The mechanisms responsible for interindividual variation in response to statin therapy remain uncertain. It has been shown that hepatic cholesterol synthesis is associated with ATP binding cassette transporter G5 and G8 (ABCG5/8) activities. To test the hypothesis that genetic variation in ABCG5/8 might influence the plasma lipid response to statin therapy, we examined five nonsynonymous polymorphisms at the ABCG5/8 loci (Q604E, D19H, Y54C, T400K, and A632V) in 338 hypercholesterolemic patients treated with 10 mg atorvastatin. In carriers of the D19H variant, means of posttreatment values and adjusted percent reductions in LDL cholesterol (LDLC) were significantly lower (P = 0.028) and greater (P = 0.036) (112 mg/dl, 39.7%) than those of noncarriers (119 mg/dl, 36.2%), respectively, while no significant difference was observed in percent reductions in total cholesterol. Stepwise multiple regression analysis revealed significant and independent associations with absolute or percent reduction between D19H genotype and posttreatment LDL cholesterol levels. The other polymorphisms were not significantly associated with treatment effects. These results suggest that, in patients with hypercholesterolemia, the ABCG8 D19H variant is associated with greater LDLC-lowering response to atorvastatin therapy.     

Statin therapy for prevention and treatment of acute and chronic cardiovascular disease: update on recent trials and metaanalyses

PURPOSE OF REVIEW: To summarize the evidence from recent clinical trials and metaanalyses on the efficacy of statin therapy to reduce death, myocardial infarction and stroke, and to review the effects of statins in patients with low LDL cholesterol, diabetes, end-stage renal disease, and acute coronary syndrome. RECENT FINDINGS: In large metaanalyses of randomized controlled trials relative risk reductions from statins compared with placebo for patients with manifest or with risk factors for coronary artery disease were 13% for overall mortality, 26% for fatal and nonfatal myocardial infarction, and 18% for fatal and nonfatal stroke. Evidence from large trials suggests that patients with type II diabetes compared with patients without diabetes have similar risk reductions from statins for cardiovascular events, but this benefit is not seen in patients with diabetes and end-stage renal disease. In patients with acute coronary syndrome, early treatment with high-dose atorvastatin reduces cardiovascular morbidity after the first 4 months following the event, but the impact on mortality endpoints remains less clear. Results from recent trials in patients with stable coronary artery disease or type II diabetes suggest that statins provide benefit at considerable low LDL cholesterol levels. Therefore, target values for LDL cholesterol of less than 1.8 mmol/l (<70 mg/dl) should be considered for all patients with coronary artery disease or equivalent coronary risk. SUMMARY: For patients at high risk of coronary artery disease there is growing evidence for the concept of 'the lower, the better' regarding LDL cholesterol levels. Ongoing trials are further investigating the safety of lower target values in patients at various risk of coronary artery disease.     

强化阿托伐他汀治疗对ACS患者血脂水平的短期影响

目的:观察强化阿托伐他汀治疗对急性冠脉综合征(ACS)患者血脂水平的短期影响。方法:收集100例ACS患者,入院当天(the day of admission,D0)、入院第一天(the first day,D1)及入院第二天(The Second Day,D2)分别给予阿托伐他汀80mg治疗,入院D0立即采血化验血脂参数包括总胆固醇(total cholesterol,TC)、低度脂蛋白(LDL-cholesterol,LDL-C)、高密度脂蛋白(HDL-cholesterol,HDL-C)、甘油三酯(triglycerides,TG),分别在D1和D2晨起空腹复查。结果:总胆固醇的平均基线水平为5.24±0.07(D0),低密度脂蛋白为3.26±0.07,高密度脂蛋白胆固醇为1.07±0.07,甘油三酯为1.31±0.07。口服阿托伐他汀80毫克后第一天早晨,TC水平下降6.1%(D1)(与D0相比P0.001),第二日下降13.2%(D2)(与D0相比P0.001),LDL-C下降5.8%(D1)(DO与D1相比,P0.001)和15.6%(D2)(DO与D2相比,P0.001);HDL-C下降7.5%(D1)(DO与D1相比,P0.001)和12.1(D2)(DO与D2相比,P0.001);相反TG水平升高20.6%(D1)(DO与D1相比,P0.001)和25.5%(D2)(DO与D2相比,P0.001)。结论:强化他汀治疗对ACS患者血脂短期的影响与长期的影响是不同的,TC,LDL和HDL在短期内是下降的,而TG是升高的。     

Insulin sensitivity regulates cholesterol metabolism to a greater extent than obesity: lessons from the METSIM Study

Cholesterol synthesis is upregulated and absorption downregulated in insulin resistance and in type 2 dia-betes. We investigated whether alterations in cholesterol metabolism are observed across the glucose tolerance status, from normoglycemia through impaired glucose tolerance to type 2 diabetes, in 781 randomly selected men 45 to 70 years of age from a population-based Metabolic Syndrome in Men Study. Cholesterol metabolism was assayed using surrogate serum markers, squalene, and noncholesterol sterols. The study population was classified into subgroups according to glucose tolerance as follows: normoglycemia, impaired fasting glucose, impaired glucose tolerance, and type 2 diabetes. LDL cholesterol did not differ between the groups. Cholesterol synthesis markers were lowest and absorption markers highest in normoglycemia. Sitosterol was lower in subjects with impaired fasting glucose compared with normoglycemic subjects (113 ± 7 vs. 136 ± 3 10² μmol/mmol of cholesterol, P < 0.05). LDL cholesterol was not associated with lathosterol/sitosterol ratio, a marker of cholesterol metabolism. Peripheral insulin sensitivity evaluated by the Matsuda index was associated with the lathosterol/sitosterol ratio in the entire population (r = −0.457, P < 0.001) and with that of lathosterol/cholestanol independently of obesity. In conclusion, cholesterol metabolism was altered already from subjects with impaired fasting glucose. Upregulated cholesterol synthesis was associated with peripheral insulin resistance independent of obesity.     

The safety and efficacy of achieving very low LDL-cholesterol concentrations with high dose statin therapy

PURPOSE OF REVIEW: The benefits of lipid lowering with statins are established in patients with or at risk for coronary artery disease. Recent trials with high doses of potent statins have examined treating to very low levels of LDL-cholesterol. Concerns have been raised about the safety of this strategy. This review examines the safety and efficacy of treating to very low LDL-cholesterol. RECENT FINDINGS: Four clinical trials, Treating to New Targets (TNT) and Incremental Decrease in End Points Through Aggressive Lipid Lowering (IDEAL) in stable coronary artery disease and Aggrastat to Zocor (A to Z) and Pravastatin or Atorvastatin Evaluation and Infection Therapy (PROVE IT)-TIMI 22 following acute coronary syndromes, have examined intensive statin therapy compared to moderate statin therapy. These trials and a meta-analysis demonstrated that intensive statin therapy reduces cardiovascular events. Subsequent analyses from these trials suggest that very low levels of LDL-cholesterol can be achieved safely and may improve clinical outcomes. A note of caution regarding hemorrhagic events following stroke with intensive statin therapy was raised by the Stroke Prevention by Aggressive Reduction of Cholesterol Levels (SPARCL) trial despite impressive reductions in cardiovascular events. SUMMARY: A growing body of evidence suggests progressive benefit for lowering LDL-cholesterol aggressively with intensive statin therapy in coronary artery disease. Future trials will be needed to define whether there is a level of LDL-cholesterol beyond which further benefit is not seen or safety concerns emerge.     

Lipidomic analysis of variation in response to simvastatin in the Cholesterol and Pharmacogenetics Study

Statins are commonly used for reducing cardiovascular disease risk but therapeutic benefit and reductions in levels of low-density lipoprotein cholesterol (LDL-C) vary among individuals. Other effects, including reductions in C-reactive protein (CRP), also contribute to treatment response. Metabolomics provides powerful tools to map pathways implicated in variation in response to statin treatment. This could lead to mechanistic hypotheses that provide insight into the underlying basis for individual variation in drug response. Using a targeted lipidomics platform, we defined lipid changes in blood samples from the upper and lower tails of the LDL-C response distribution in the Cholesterol and Pharmacogenetics study. Metabolic changes in responders are more comprehensive than those seen in non-responders. Baseline cholesterol ester and phospholipid metabolites correlated with LDL-C response to treatment. CRP response to therapy correlated with baseline plasmalogens, lipids involved in inflammation. There was no overlap of lipids whose changes correlated with LDL-C or CRP responses to simvastatin suggesting that distinct metabolic pathways govern statin effects on these two biomarkers. Metabolic signatures could provide insights about variability in response and mechanisms of action of statins.     

Intensive statin therapy in acute coronary syndromes: clinical benefits and vascular biology

PURPOSE OF REVIEW: The results of a landmark clinical study comparing intensive statin therapy with conventional statin therapy, in patients with acute coronary syndromes (ACS), are reviewed. The mechanisms behind these results are analysed drawing data from vascular and cell biology. RECENT FINDINGS: The Pravastatin or Atorvastatin Evaluation and Infection Therapy-Thrombolysis in Myocardial Infarction (PROVE IT-TIMI 22) study showed that intensive statin therapy with 80 mg of atorvastatin to achieve a low-density lipoprotein cholesterol of 62 mg/dl resulted in a 3.9% absolute and a 16% relative risk reduction in death or major cardiovascular events up to 2 years, compared to 40 mg of pravastatin, in patients with ACS. The results were especially significant as intensive statin therapy resulted in a very early benefit (<30 days) and occurred against a background of percutaneous coronary intervention (69%) for the index admission and high use of medications for secondary prevention. The PROVE IT and the Myocardial Ischaemia Reduction with Aggressive Cholesterol Lowering (MIRACL) C-reactive protein sub-study also showed that atorvastatin (80 mg) resulted in a significant reduction in markers of inflammation, whilst the Reversal of Atherosclerosis with Aggressive Lipid Lowering (REVERSAL) study showed that intensive statin therapy was associated with reduced progression of atherosclerosis compared with conventional doses of statins. SUMMARY: Intensive statin therapy results in a significant early reduction in adverse cardiac events in ACS patients which are sustained over 2 years. The early benefits seen are likely to result from modulation of inflammation, endothelial function and coagulation, i.e. the pleiotropic effects, whereas the greater reduction in low-density lipoprotein cholesterol results in reduced long-term events.     

Beyond blood lipids: phytosterols,statins and omega-3 polyunsaturated fatty acid therapy for hyperlipidemia

Phytosterols and omega-3 fatty acids are natural compounds with potential cardiovascular benefits. Phytosterols inhibit cholesterol absorption, thereby reducing total- and LDL cholesterol. A number of clinical trials have established that the consumption of 1.5–2.0 g/day of phytosterols can result in a 10–15% reduction in LDL cholesterol in as short as a 3-week period in hyperlipidemic populations. Added benefits of phytosterol consumption have been demonstrated in people who are already on lipid-lowering medications (statin drugs). On the other hand, omega-3 fatty acid supplementation has been associated with significant hypotriglyceridemic effects with concurrent modifications of other risk factors associated with cardiovascular disease, including platelet function and pro-inflammatory mediators. Recent studies have provided evidence that the combination of phytosterols and omega-3 fatty acids may reduce cardiovascular risk in a complementary and synergistic way. This article reviews the health benefits of phytosterols and omega-3 fatty acids, alone or in combination with statins, for the treatment/management of hyperlipidemia, with particular emphasis on the mechanisms involved.     

Modified methylenedioxyphenol analogs lower LDL cholesterol through induction of LDL receptor expression

Although statin therapy is a cornerstone of current low density lipoprotein (LDL)-lowering strategies, there is a need for additional therapies to incrementally lower plasma LDL cholesterol. In this study, we investigated the effect of several methylenedioxyphenol derivatives in regulating LDL cholesterol through induction of LDL receptor (LDLR). INV-403, a modified methylenedioxyphenol derivative, increased LDLR mRNA and protein expression in HepG2 cells in a dose- and time-dependent fashion. These effects were apparent even under conditions of HMG-CoA reductase inhibition. Electrophoresis migration shift assays demonstrated that INV-403 activates SREBP2 but not SREBP1c, with immunoblot analysis showing an increased expression of the mature form of SREBP2. Knockdown of SREBP2 reduced the effect of INV-403 on LDLR expression. The activation of SREBP2 by INV-403 is partly mediated by Akt/GSK3β pathways through inhibition of phosphorylation-dependent degradation by ubiquitin-proteosome pathway. Treatment of C57Bl/6j mice with INV-403 for two weeks increased hepatic SREBP2 levels (mature form) and upregulated LDLR with concomitant lowering of plasma LDL levels. Transient expression of a LDLR promoter-reporter construct, a SRE-mutant LDLR promoter construct, and a SRE-only construct in HepG2 cells revealed an effect predominantly through a SRE-dependent mechanism. INV-403 lowered plasma LDL cholesterol levels through LDLR upregulation. These results indicate a role for small molecule approaches other than statins for lowering LDL cholesterol.     

Influence of experimental diets on cholesterol and triglyceride levels of rabbit blood serum lipoproteins

Groups of rabbits were fed for six weeks various diets: standard died + ethanol, high-cholesterol diet and a high-cholesterol + ethanol one. During the next six weeks every diet was supplemented with a fresh vegetable (carrot). Cholesterol and triglycerides were determined in the whole serum and in lipoprotein fractions. In rabbits fed standard diet ethanol caused a moderate elevation of VLDL cholesterol and triglyceride and LDL cholesterol levels. In animals on high-cholesterol diet cholesterol and triglyceride concentrations in these fractions were very high. Simultaneous consumption of large amounts of cholesterol and of ethanol resulted in a greater rise of cholesterol concentration in the whole serum and in VLDL and LDL fraction than did high-cholesterol diet alone. Addition of carrot caused a pronounced reduction of serum cholesterol concentration in animals fed all kinds of diets. The reduction concerned mainly VLDL.