Drug treatment of lipid disorders

Pathophysiology and treatment of the dyslipidemia of insulin resistance

Insulin resistance, and the compensatory hyperinsulinemia that results, has been linked to a host of defects including glucose intolerance, diabetes, hypertension, dyslipidemia, endothelial dysfunction, impaired fibrinolysis, and subclinical inflammation. Patients with this metabolic syndrome have a markedly increased risk for the development of atherothrombotic cardiovascular disease. The characteristic dyslipidemia of insulin resistance consists of elevated triglyceride and triglyceride-rich lipoprotein levels, low levels of high-density lipoprotein cholesterol, and increased concentrations of small, dense low-density lipoprotein cholesterol. Management of this dyslipidemia typically involves a dual approach. Lifestyle modification is an essential component of any successful treatment plan, but alone is usually insufficient to correct these lipoprotein abnormalities. Medications that diminish insulin resistance and directly alter lipoproteins are also necessary in the majority of cases. Combinations of therapeutic agents are often required to optimize attainment of treatment goals.

Effects of sibutramine on body weight and serum lipids: a double-blind, randomized, placebo-controlled study in 322 overweight and obese patients with dyslipidemia

BACKGROUND

Cardiovascular risk factors associated with obesity, including dyslipidemia, can be improved by weight loss. The main dyslipidemia associated with obesity is elevated serum triglyceride and decreased serum high-density lipoprotein cholesterol (HDL-C) levels.

METHODS

A total of 322 obese patients (body mass index > or = 27) with serum triglyceride levels > or = 250 mg/dL and < or = 1000 mg/dL and serum HDL-C levels < or = 45 mg/dL (women) and < or = 40 mg/dL (men) were placed on a step I American Heart Association diet and subsequently randomized to sibutramine 20 mg (n = 162) or placebo (n = 160) once daily for 24 weeks.

RESULTS

Patients taking sibutramine had significantly greater mean weight loss than those receiving placebo (-4.9 kg vs -0.6 kg, P < or = .05). Forty-two percent of the sibutramine group lost > or = 5% of baseline weight and 12% lost > or = 10% compared with 8% and 3%, respectively, of the placebo group (P < or = .05). Mean decreases in serum triglyceride levels among 5% and 10% weight-loss responders in the sibutramine group were 33.4 mg/dL and 72.3 mg/dL, respectively, compared with an increase of 31.7 mg/dL among all patients receiving placebo (P < or = .05). Mean increases in serum HDL-C levels for 5% and 10% weight-loss responders in the sibutramine group were 4.9 mg/dL and 6.7 mg/dL, respectively, compared with an increase of 1.7 mg/dL among all patients in the placebo group (P < or = .05). Adverse events and discontinuation rates were similar in the sibutramine and placebo groups, although sibutramine-treated patients had mean increases in systolic and diastolic blood pressure of 2 to 3 mm Hg relative to placebo.

CONCLUSIONS

In overweight and obese patients with high serum triglyceride levels and low serum HDL-C levels, treatment with sibutramine was associated with significant improvements in body weight and in serum triglyceride and HDL-C levels.

Lipid disorders: justification of methods and goals of treatment

Dyslipidemia is a major risk factor for coronary heart disease (CHD). While some uncertainty exists about the clinical significance of improving high-density lipoprotein cholesterol and triglyceride levels, large primary- and secondary-prevention studies aimed at lowering low-density lipoprotein cholesterol levels with statins have convincingly reduced CHD events and total mortality. Despite the strong clinical evidence and widely publicized treatment guidelines, many hyperlipidemic patients receive inadequate lipid-lowering treatment. This failure to achieve clinical treatment goals may be due to poor physician adherence to treatment guidelines, patient noncompliance, and the presence of concomitant medical conditions that modify typical hyperlipidemia management. This review considers the challenges and available strategies to optimize lipid management in patients at risk for CHD.

Effectiveness and tolerability of ezetimibe in patients with primary hypercholesterolemia: pooled analysis of two phase II studies

BACKGROUND

Ezetimibe (SCH 58235) is a novel cholesterol absorption inhibitor that selectively and potently blocks intestinal absorption of dietary and biliary cholesterol.

OBJECTIVE

Data from 2 multicenter, placebo-controlled, double-blind, randomized, parallel-group, 12-week studies of ezetimibe were pooled to evaluate the drug's effect on lipid parameters in patients with primary hypercholesterolemia.

METHODS

After dietary stabilization (National Cholesterol Education Program Step I diet or a stricter diet), washout of lipid-altering drugs, and a 6-week placebo lead-in period, patients with baseline plasma low-density lipoprotein cholesterol (LDL-C) levels > or = 130 and < or = 250 mg/dL and plasma triglyceride (TG) levels < or = 300 mg/dL were randomized to receive either ezetimibe 0.25, 1, 5, or 10 mg, or placebo administered once daily before the morning meal in study A (dose-response study) or ezetimibe 5 or 10 mg or placebo administered once daily before the morning meal or at bedtime in study B (dose-regimen study).

RESULTS

A total of 432 patients were included in this pooled analysis, 243 in study A and 189 in study B. The 5- and 10-mg doses of ezetimibe significantly reduced LDL-C levels by 15.7% and 18.5%, respectively (P < 0.01 vs placebo) and significantly increased high-density lipoprotein cholesterol (hDL-C) levels by 2.9% and 3.5%, respectively (P < 0.05 vs placebo). A reduction in plasma TG levels was observed (P = NS). With the 10-mg dose of ezetimibe, 67.8% of patients achieved > or = 15% reduction in plasma LDL-C levels, and 22.0% achieved > or = 25% reduction. With the 5-mg dose, 54.0% of patients achieved > or = 15% reduction in plasma LDL-C levels, and 15.3% achieved > or = 25% reduction. The decrease in plasma LDL-C levels was significantly greater with ezetimibe 10 mg compared with ezetimibe 5 mg (P < 0.05). Ezetimibe was well tolerated, with an adverse event profile similar to that of placebo.

CONCLUSIONS

In these two 12-week studies, ezetimibe significantly decreased plasma LDL-C levels and increased plasma HDL-C levels, with a tolerability profile similar to that of placebo.

Dyslipidemia

The major goal in treatment of patients with dyslipidemia is to decrease the short- and long-term incidence of cardiovascular events, including myocardial infarction, unstable angina, stroke, and death. A second goal in patients with severe hypertriglyceridemia is to decrease the risk of acute pancreatitis. Improvement of the lipid profile can be achieved through a combination of aggressive lifestyle modification and effective drug therapy. Treatment should be tailored to the individual patient, based on the specific lipid abnormalities, the presence or absence of pre-existing coronary artery or other atherosclerotic vascular disease, and an assessment of overall cardiovascular risk.

Strategies for treating HIV-related lipodystrophy

HIV-related lipodystrophy has emerged as one of the most prevalent problems for patients with HIV, since this infection can now be seen as a chronic disease. Despite its growing importance, crucial issues such as aetiopathogenesis, diagnosis, prevention and therapy remain largely unknown and unexplored. Current evidence suggests that aetiology is multifactorial. HIV infection, antiretroviral therapy and patient-related factors probably all contribute to the development of lipodystrophy. The lack of a formal definition and the nature of wasting syndromes that affect HIV-infected patients can hinder the diagnosis and treatment of lipodystrophy. Body fat changes have a major negative impact on the quality of life of patients. Metabolic abnormalities are also well known cardiovascular risk factors that can increase the morbidity and mortality due to cardiovascular disorders in a relatively young population. As yet, we do not know whether lipodystrophy is preventable or reversible. Several therapeutic approaches have been tested with limited success, however potential complications must be considered. These therapeutic approaches include general health measures (diet, exercise and discontinuation of smoking), switching antiretrovirals (from protease inhibitors to non-nucleoside reverse transcriptase inhibitors or abacavir, or from stavudine to other nucleoside reverse transcriptase inhibitors) and use of drugs with metabolic effects (metformin, thiazolidinediones, recombinant growth hormone and anabolic steroids). A judicious use of available data, and opting for an individualised approach seems the best option for management of this problem at present.

A new statin: a new standard

Numerous studies have demonstrated that treatments designed to reduce low-density lipoprotein cholesterol (LDL-C) can reduce the risk of coronary heart disease (CHD) events in the setting of either primary or secondary prevention. The rationale for aggressive lowering of LDL-C, supported by large observational studies, is the concept that no threshold exists below which reductions fail to provide additional benefit. The statins are widely considered first-line therapy for preventing CHD events because these agents yield the greatest reductions in LDL-C. However, many patients do not achieve target LDL-C levels with the currently available statins. Newer, more effective statins may permit the benefits of aggressive LDL-C reduction to be extended to larger numbers of patients. A novel, highly efficacious statin, rosuvastatin (Crestor, AstraZeneca group of companies), is currently undergoing clinical investigation. Dose-ranging studies in hypercholesterolemic patients have shdwn that rosuvastatin produces significant, dose-dependent decreases in LDL-C when compared with placebo. Reductions have ranged from 34% at a dose of 1 mg/day to 65% at 80 mg/day. This agent has been found to be well tolerated across the range of doses studied. Phase III studies indicate that rosuvastatin is more effective than atorvastatin, pravastatin, and simvastatin in improving the atherogenic lipid profiles of hypercholesterolemic patients, and more effective than atorvastatin in improving the atherogenic lipid profiles of patients with heterozygous familial hypercholesterolemia. Overall, these findings suggest that rosuvastatin is a promising new medication for the treatment of dyslipidemias.

Timing treatment to the rhythm of disease. A short course in chronotherapeutics

The recognition of circadian rhythms in both normal human biologic function and disease has heightened the awareness that the timing of drug regimens may have an important impact on effectiveness of treatment. Outcomes in several diseases that have predictable circadian variations (e.g., arthritis, asthma, allergies, pepticulcer disease, dyslipidemia, cancer) have been improved by matching the timing of medication use to the circadian rhythm of the illness. Results of the ongoing CONVINCE study may provide evidence that chronotherapy for hypertension and angina pectoris may be more effective than traditional homeostatic treatment.

Simvastatin-associated memory loss

The statins are widely used to treat dyslipidemias. They are generally associated with mild adverse effects, but rarely, more serious reactions may occur. A 51-year-old man experienced delayed-onset, progressive memory loss while receiving simvastatin for hypercholesterolemia. His therapy was switched to pravastatin, and memory loss resolved gradually over the next month, with no recurrence of the adverse effect.

New recommendations from the 1999 American College of Cardiology/American Heart Association acute myocardial infarction guidelines

OBJECTIVE

To review literature relating to significant changes in drug therapy recommendations in the 1999 American College of Cardiology (ACC)/American Heart Association (AHA) guidelines for treating patients with acute myocardial infarction (AMI).

DATA SOURCES

1999 ACC/AHA AMI guidelines, English-language clinical trials, reviews, and editorials researching the role of drug therapy and primary angioplasty for AMI that were referenced in the guidelines were included. Additional data published in 2000 or unpublished were also included if relevant to interpretation of the guidelines.

STUDY SELECTION

The articles selected influence AMI treatment recommendations.

DATA SYNTHESIS

Many clinicians and health systems use the ACC/AHA AMI guidelines to develop treatment plans for AMI patients. This review highlights important changes in AMI drug therapy recommendations by reviewing the results of recent clinical trials. Insights into evolving drug therapy strategies that may impact future guideline development are also described.

CONCLUSIONS

Several changes in drug therapy recommendations were included in the 1999 AMI ACC/AHA guidelines. There is emphasis on administering fibrin-specific thrombolytics secondary to enhanced efficacy. Selection between fibrin-specific agents is unclear at this time. Low response rates to thrombolytics have been noted in the elderly, women, patients with heart failure, and those showing left bundle-branch block on the electrocardiogram. These patient groups should be targeted for improved utilization programs. The use of glycoprotein (GP) IIb/IIIa receptor inhibitors in non-ST-segment elevation MI was emphasized. Small trials combining reduced doses of thrombolytics with GP IIb/IIIa receptor inhibitors have shown promise by increasing reperfusion rates without increasing bleeding risk, but firm conclusions cannot be made until the results of larger trials are known. Primary percutaneous coronary intervention (PCI) trials suggest lower mortality rates for primary PCI when compared with thrombolysis alone. However, primary PCI, including coronary angioplasty, is only available at approximately 13% of US hospitals, making thrombolysis the preferred strategy for most patients. Clopidogrel has supplanted ticlopidine as the recommended antiplatelet agent for patients with aspirin allergy or intolerance following reports of a better safety profile. The recommended dose of unfractionated heparin is lower than previously recommended, necessitating a separate nomogram for patients with acute coronary syndromes. Routine use of warfarin, either alone or in combination with aspirin, is not supported by clinical trials; however, warfarin remains a choice for antithrombotic therapy in patients intolerant to aspirin. Beta-adrenergic receptor blockers continue to be recommended, and emphasis is placed on improving rates of early administration (during hospitalization), even in patients with moderate left ventricular dysfunction. New recommendations for drug treatment of post-AMI patients with low high-density lipoprotein cholesterol and/or elevated triglycerides are included, with either niacin or gemfibrozil recommended as an option. Supplementary antioxidants are not recommended for either primary or secondary prevention of AMI, with new data demonstrating lack of efficacy vitamin E in primary prevention. Estrogen replacement therapy or hormonal replacement therapy should not be initiated solely for prevention of cardiovascular disease, but can be continued in cardiovascular patients already taking long-term therapy for other reasons. Bupropion has been added as a new treatment option for smoking cessation. As drug therapy continues to evolve in treating AMI, more frequent updates of therapy guidelines will be necessary.

Bexarotene is effective and safe for treatment of refractory advanced-stage cutaneous T-cell lymphoma: multinational phase II-III trial results

PURPOSE

Cutaneous T-cell lymphomas (CTCL) are malignancies of T cells appearing as skin lesions and are responsive to retinoid therapy. Safety and efficacy of a novel RXR-selective retinoid (rexinoid) bexarotene (Targretin, LGD1069; Ligand Pharmaceuticals Inc, San Diego, CA) was evaluated as a single-agent oral therapy administered once daily in an open-label study in patients with refractory advanced-stage CTCL.

PATIENTS AND METHODS

Ninety-four patients with biopsy-confirmed CTCL in advanced stages (IIB-IVB) were enrolled at 26 centers. Fifty-six patients received an initial dose of 300 mg/m2/d oral bexarotene and 38 started at more than 300 mg/m2/d.

RESULTS

Clinical complete and partial responses were reported by Primary End point Classification for the study in 45% (25 of 56) of patients enrolled at 300 mg/m2/d dosing. At more than 300 mg/m2/d, 55% (21 of 38) of patients responded, including 13% (five of 38) clinical complete. For the 300 mg/m2/d initial dose group, the rate of relapse after response was 36% and the projected median duration of response was 299 days. Improvements were also seen in overall body-surface area involvement, median index lesion surface area, adenopathy, cutaneous tumors, pruritus, and CTCL-specific quality of life. The most frequent drug-related adverse events included hypertriglyceridemia (associated rarely with pancreatitis), hypercholesterolemia, hypothyroidism, and headache.

CONCLUSION

Bexarotene is the first in a novel class of pharmacologic agents, the RXR-selective retinoids, or rexinoids. Bexarotene is orally administered, safe, and generally well tolerated with reversible side effects, and is effective for the treatment of advanced, refractory CTCL.

Statin therapy decreases the risk of osteonecrosis in patients receiving steroids

Osteonecrosis is a devastating complication of systemic steroid use. Prolonged steroid use produces a hyperlipidemic state in most patients and puts them at risk for osteoporosis and osteonecrosis. The fat content within the femoral head increases, resulting in increased intracortical pressure that may lead to sinusoidal collapse and osteonecrosis. Statins are lipid-clearing agents that dramatically reduce lipid levels in blood and tissues. Statins are widely used to prevent cardiovascular disease and have been shown to reduce the adverse effects of steroids on lipid metabolism. The purpose of this study was to determine whether the use of statin drugs affects later development of osteonecrosis in patients receiving steroids. The records of 284 patients who were taking statin drugs at the time they were started on high dose steroids were examined to determine whether osteonecrosis had developed. The patients remained on statin drugs during the entire time of steroid exposure. Magnetic resonance imaging scans were used to verify the osteonecrosis unless it was visible by radiograph. After an average of 7.5 years (minimum followup, 5 years), only three patients (1%) from the group had osteonecrosis develop. This 1% incidence is much less than the 3% to 20% incidence usually reported for patients receiving high-dose steroids. Statins may offer some protection against having osteonecrosis develop when steroid treatment is necessary.

Effect of lipid-lowering therapy on early mortality after acute coronary syndromes: an observational study

BACKGROUND

Lipid-lowering agents are known to reduce long-term mortality in patients with stable coronary disease or significant risk factors. However, the effect of lipid-lowering therapy on short-term mortality immediately after an acute coronary syndrome has not been determined. We did an observational study using data from two randomised trials to investigate this issue.

METHODS

We used data from the GUSTO IIb and PURSUIT trials to compare all-cause mortality among patients with acute coronary syndromes who were discharged on lipid-lowering agents (n=3653) with those who were not (n=17,156). A propensity analysis was done to adjust for presumed selection biases in the prescription of lipid-lowering agents.

FINDINGS

Lipid-lowering therapy was associated with a smaller proportion of deaths at 30 days (17 [0.5%] vs 179 [1.0%], hazard ratio 0.44 [95% CI 0.27-0.73], p=0.001) and at 6 months (63 [1.7%] vs 605 [3.5%], 0.48 [0.37-0.63], p<0.0001). After adjustment for the propensity to be prescribed lipid-lowering agents and other potential confounders, prescription of a lipid-lowering agent at discharge remained associated with a reduced risk of death at 6 months (0.67 [0.48-0.95], p=0.023).

INTERPRETATION

Prescription of a lipid-lowering drug at hospital discharge was independently associated with reduced short-term mortality among patients after an acute coronary syndrome.

Efficacy and safety of combination simvastatin and colesevelam in patients with primary hypercholesterolemia

PURPOSE

To examine the efficacy and safety of colesevelam hydrochloride, a novel, nonsystemic, lipid-lowering agent, when coadministered with starting doses of simvastatin in a multicenter, randomized, double-blind, placebo-controlled trial.

PATIENTS AND METHODS

Subjects with hypercholesterolemia (plasma low density lipoprotein [LDL] cholesterol level > 160 mg/dL and triglyceride level < or = 300 mg/dL) were randomly assigned to receive daily doses of placebo (n = 33), colesevelam 3.8 g (recommended dose, n = 37), simvastatin 10 mg (n = 35), colesevelam 3.8 g with simvastatin 10 mg (n = 34), colesevelam 2.3 g (low dose, n = 36), simvastatin 20 mg (n = 39), or colesevelam 2.3 g with simvastatin 20 mg (n = 37), for 6 weeks.

RESULTS

Mean LDL cholesterol levels decreased relative to baseline in the placebo group (P < 0.05) and in all active treatment groups (P < 0.0001). For groups treated with combination therapy, the mean reduction in LDL cholesterol level was 42% (-80 mg/dL; P < 0.0001 compared with baseline), which exceeded the reductions for simvastatin 10 mg (-26%, -48 mg/dL) or 20 mg (-34%, -61 mg/dL) alone, or for colesevelam 2.3 g (-8%, -17 mg/dL) or 3.8 g (-16%, -31 mg/dL) alone (P < 0.001). The effects of combination therapy on serum HDL cholesterol and triglyceride levels were similar to those for simvastatin alone. Side effects were similar among treatment groups, and there were no clinically important changes in laboratory parameters.

CONCLUSION

Coadministration of colesevelam and simvastatin was effective and well tolerated, providing additive reductions in LDL cholesterol levels compared with either agent alone.

Renoprotection: one or many therapies?

BACKGROUND

Renal disease that progresses to end-stage renal disease (ESRD) imposes a great burden on the affected individual and on society, which mainly bears the cost of ESRD (currently more than $10 billion to treat about 333,000 patients annually in the U.S.). Thus, there is a great need to identify therapies that arrest the progression mechanisms common to all forms of renal disease. Progress is being made. Perhaps the most visible advance is the randomized controlled trials (RCT) demonstrating the renoprotective effects of angiotensin-converting enzyme (ACE) inhibitors. There are also numerous other promising renoprotective therapies. Unfortunately, testing each therapy in RCT is not feasible. Thus the nephrologist has two choices: restrict renoprotective therapy to those shown to be effective in RCT, or expand the use of renoprotective therapies to include those that, although unproven, are plausibly effective and prudent to use. The goal of this work is to provide the documentation needed for the nephrologist to choose between these strategies.

METHODS

This work first describes the mechanisms believed to be involved in the progression of renal disease. Based largely on this information, 18 separate interventions that slow the progression are described. Each intervention is assigned a level of recommendation (Level 1 is the highest and Level 3 the lowest) according to the strength of evidence supporting its renoprotective efficacy.

RESULTS

The number of interventions at each level of recommendation are: Level 1, N = 4; Level 2, N = 4; Level 3, N = 10. Our own experience with the multiple-risk-factor intervention is that most patients can achieve the majority of the Level 1 and 2 interventions, and many of the Level 3 interventions. We recommend the expanded renoprotection strategy.

CONCLUSION

This work advances the hypothesis that, until better information becomes available, a broad-based, multiple-risk-factor intervention intended to slow the progression of renal disease can be justified in those with progressive nephropathies. This work is intended primarily for clinical nephrologists and thus each recommended intervention is described in substantial practical detail.

Alternate-day dosing of HMG-CoA reductase inhibitors for cholesterol reduction

OBJECTIVE

Assess efficacy, safety, and cost of alternate-day dosing with 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (HRIs).

DATA

International Pharmaceutical Abstracts and MEDLINE (English-language clinical trials, 1966-April 2000) were searched.

DATA SYNTHESIS

Established efficacy of HRIs is based on daily administration. Many patients who could benefit from these agents are unable to afford them; therefore, alternate-day dosing may be a solution for reducing expense without decreasing therapy benefits. Studies addressing alternate-day HRI therapy are evaluated to determine the usefulness of this option for cholesterol reduction.

CONCLUSIONS

Although limited studies imply a trend toward benefit with alternate-day HRI therapy, large, controlled, randomized trials are needed before making this a standard recommendation.

A novel series of highly potent benzimidazole-based microsomal triglyceride transfer protein inhibitors

A series of benzimidazole-based analogues of the potent MTP inhibitor BMS-201038 were discovered. Incorporation of an unsubstituted benzimidazole moiety in place of a piperidine group afforded potent inhibitors of MTP in vitro which were weakly active in vivo. Appropriate substitution on the benzimidazole ring, especially with small alkyl groups, led to dramatic increases in potency, both in a cellular assay of apoB secretion and especially in animal models of cholesterol lowering. The most potent in this series, 3g (BMS-212122), was significantly more potent than BMS-201038 in reducing plasma lipids (cholesterol, VLDL/LDL, TG) in both hamsters and cynomolgus monkeys.

Statin therapy and reductions in low-density lipoprotein cholesterol: initial clinical data on the potent new statin Rosuvastatin

The utility of statins with increased potency in reducing low-density lipoprotein cholesterol (LDL-C) is indicated by evidence that aggressive LDL-C lowering is associated with increased reduction in coronary artery disease risk, and the need for such agents is illustrated by the fact that many patients currently fail to achieve LDL-C target levels during treatment with available drugs. In dose-ranging studies of patients with hypercholesterolemia, the new synthetic statin rosuvastatin (formerly ZD4522) produced significant, dose-dependent reductions in LDL-C compared with placebo across a range of doses. Reductions ranged from 34% at 1 mg per day to 65% at 80 mg per day, with linear regression analysis indicating an additional 4.5% reduction in LDL-C with each doubling of the rosuvastatin dose. Rosuvastatin treatment was well tolerated. Phase 3 clinical trials of this agent are under way.

Pro and con: low-density lipoprotein cholesterol lowering is and will be the key to the future of lipid management

A wealth of data demonstrate that reduction of cholesterol levels is associated with benefit in reducing coronary artery disease risk. The magnitude of benefit observed with statin treatment, which acts primarily to reduce low-density lipoprotein cholesterol (LDL-C), is greater than that observed with any other lipid-modifying intervention, and data from large statin trials indicate that this benefit is caused by LDL-C reduction. Statin treatment is highly cost-effective compared with other accepted therapies, at least in the secondary prevention setting, and has a superior safety and tolerability profile. For the foreseeable future, LDL-C reduction will remain the goal of lipid-modifying therapy, and statins will remain the primary therapeutic modality for achieving that goal.

Preclinical and clinical pharmacology of Rosuvastatin, a new 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor

Rosuvastatin (formerly ZD4522) is a new 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor (statin) with distinct pharmacologic properties. Compared with most other statins, it is relatively hydrophilic, similar in this respect to pravastatin. Rosuvastatin has been shown to be a comparatively potent inhibitor of HMG-CoA reductase activity in a purified preparation of the catalytic domain of the human enzyme, as well as in rat and human hepatic microsomes. In rat hepatocytes, rosuvastatin was found to have significantly higher potency as an inhibitor of cholesterol synthesis than 5 other statins. Rosuvastatin was approximately 1,000-fold more potent in rat hepatocytes than in rat fibroblasts. Further studies in rat hepatocytes demonstrated that rosuvastatin is taken up into these cells by a high-affinity active uptake process. Rosuvastatin was also taken up selectively into the liver after intravenous administration in rats. Potent and prolonged HMG-CoA reductase inhibitory activity has been demonstrated after oral administration to rats and dogs. Pharmacokinetic studies in humans using oral doses of 5 to 80 mg showed that maximum plasma concentrations and areas under the concentration-time curve are approximately linear with dose. The terminal half-life is approximately 20 hours. Studies with human hepatic microsomes and human hepatocytes have suggested little or no metabolism via the cytochrome P-450 3A4 isoenzyme. On the basis of these observations, it is suggested that rosuvastatin has the potential to exert a profound effect on atherogenic lipoproteins.

Peroxisome proliferator-activated receptor (PPAR)-alpha activation lowers muscle lipids and improves insulin sensitivity in high fat-fed rats: comparison with PPAR-gamma activation

Peroxisome proliferator-activated receptor (PPAR)-alpha agonists lower circulating lipids, but the consequences for muscle lipid metabolism and insulin sensitivity are not clear. We investigated whether PPAR-alpha activation improves insulin sensitivity in insulin-resistant rats and compared the effects with PPAR-gamma activation. Three-week high fat-fed male Wistar rats were untreated or treated with the specific PPAR-alpha agonist WY14643 or the PPAR-gamma agonist pioglitazone (both 3 mg x kg(-1) x day(-1)) for the last 2 weeks of high-fat feeding. Like pioglitazone, WY14643 lowered basal plasma levels of glucose, triglycerides (-16% vs. untreated), and leptin (-52%), and also muscle triglyceride (-34%) and total long-chain acyl-CoAs (LCACoAs) (-41%) (P < 0.05). In contrast to pioglitazone, WY14643 substantially reduced visceral fat weight and total liver triglyceride content (P < 0.01) without increasing body weight gain. WY14643 and pioglitazone similarly enhanced whole-body insulin sensitivity (clamp glucose infusion rate increased 35 and 37% and glucose disposal 22 and 15%, respectively, vs. untreated). Both agents enhanced insulin-mediated muscle glucose metabolic index (Rg') and reduced muscle triglyceride and LCACoA accumulation (P < 0.05). Although pioglitazone had more potent effects than WY14643 on muscle insulin sensitization, this was associated with its greater effect to reduce muscle LCACoA accumulation. Overall insulin-mediated muscle Rg' was inversely correlated with the content of LCACoAs (r = -0.74, P = 0.001) and with plasma triglyceride levels (r = -0.77, P < 0.001). We conclude that even though WY14643 and pioglitazone, representing PPAR-alpha and PPAR-gamma activation, respectively, may alter muscle lipid supply by different mechanisms, both significantly improve muscle insulin action in the high fat-fed rat model of insulin resistance, and this effect is proportional to the degree to which they reduce muscle lipid accumulation.

Nutritional and medical therapy for dyslipidemia in patients with cardiovascular disease

Dyslipidemia is a significant risk factor for the progression of cardiovascular disease, particularly when associated with other risk factors. An understanding of the pathophysiology and risks for patients with atherosclerotic diseases of undertreated dyslipidemia is essential for the healthcare provider. In this article, a review of epidemiologic data regarding the role of lipid levels in cardiovascular disease prognosis is presented. A familiarity with current dietary and drug treatment of lipid disorders is at the core of an evidence-based approach to dyslipidemia management in the patient with established cardiovascular diseases.

Statins for the reduction of risk of Alzheimer's disease

BACKGROUND

: Two recent clinical reports describe an association between statin therapy and a reduction in the occurrence of Alzheimer's disease by as much as 70 %. One report is a cross-sectional analysis of discharges among three hospitals, and the other is a nested case control study drawn from ambulatory patients of general practitioners in the UK. Because neither study is a randomized trial, the association noted between statin therapy and a reduced incidence of Alzheimer's disease may have occurred because other factors, unaccounted for in the studies, may be present (so called bias) and be responsible for the observed association. However, there is an expanding body of biological and epidemiological data that makes it plausible that statin therapy may retard or prevent the pathogenesis and clinical expression of Alzheimer's disease. This review was initiated in order to find other clinical evidence that might support or refute the hypothesized benefit of statin therapy.

OBJECTIVES

: The purpose is to review the evidence that treatment with statins reduces the risk of Alzheimer's disease.

SEARCH STRATEGY

: The following data bases were searched: Specialised Register of the Cochrane Dementia and Cognitive Improvement Group, MEDLINE (1966-2000/12), EMBASE (1980-2000/12), and Psych Info (1987-2000/11). Search terms included statins,lovastatin, pravastatin, simvastatin, alzheimer*, dement*, cogn*.

SELECTION CRITERIA

: In order to be selected, trials needed to be randomized, doubled blinded, and of sufficient duration( probably years rather than weeks or months) to ascertain the preventive potential of statin therapy.

DATA COLLECTION AND ANALYSIS

: Data were to be extracted independently by two reviewers and pooled where appropriate and possible. The pooled odds ratios (95% CI) or the average differences were to be estimated.

MAIN RESULTS

: There were no randomized trials found in the search.

REVIEWER'S CONCLUSIONS

: There is no good evidence to recommend statins for reducing the risk of Alzheimer's disease. There is, however, a growing body of biological, epidemiological, and limited but non-randomized clinical evidence that lowering serum cholesterol may retard the pathogenesis of Alzheimer's disease. Mounting the clinical studies to determine the potential benefit of statin therapy should be a high priority for future research agendas.

Rhabdomyolysis secondary to a drug interaction between simvastatin and clarithromycin

OBJECTIVE

To report a case of rhabdomyolysis resulting from concomitant use of clarithromycin and simvastatin.

CASE SUMMARY

A 64-year-old African-American man was admitted to the hospital for worsening renal failure, elevated creatine phosphokinase, diffuse muscle pain, and severe muscle weakness. About three weeks prior to admission, the patient was started on clarithromycin for sinusitis. The patient had been receiving simvastatin for approximately six months. He was treated aggressively with intravenous hydration, sodium bicarbonate, and hemodialysis. A muscle biopsy revealed necrotizing myopathy secondary to a toxin. The patient continued to receive intermittent hemodialysis until his death from infectious complications that occurred three months after admission. There were several factors that could have increased his risk for developing rhabdomyolysis, including chronic renal failure.

DISCUSSION

Clarithromycin is a potent inhibitor of CYP3A4, the major enzyme responsible for simvastatin metabolism. The concomitant administration of macrolide antibiotics and other hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have resulted in previous reports of rhabdomyolysis. Other factors may increase the risk of this drug interaction, including the administration of other medications that are associated with myopathy, underlying renal insufficiency, and administration of high doses of HMG-CoA reductase inhibitors.

CONCLUSIONS

Macrolide antibiotics inhibit the metabolism of HMG-CoA reductase inhibitors that are metabolized by CYP3A4 (i.e., atorvastatin, cerivastatin, lovastatin, simvastatin). This interaction may result in myopathy and rhabdomyolysis, particularly in patients with renal insufficiency or those who are concurrently taking medications associated with myopathy.

The management of the clinical complications of antiretroviral therapy

In clinical practice, combination antiretroviral therapy is frequently complicated by adverse reactions and drug-related toxicities. The incidence, presentation, differential diagnosis, and management of the most frequent and severe of these complications are discussed. The recently described spectrum of metabolic complications, including hyperlipidemia, fat redistribution, and lactic acidosis, are covered in detail. The management of nephrotoxicity, pancreatitis, bone marrow suppression, peripheral neuropathy, and hypersensitivity reactions related to antiretroviral therapy is also discussed.

Significant Toxicities Associated with Antiretroviral Therapy

Use of at least three potent antiretroviral agents has become the standard of care in the management of HIV infection. The potential toxicities associated with highly active antiretroviral therapy (HAART) however, may limit a patient’s ability to adhere to and tolerate these agents. Although a comprehensive discussion of all toxicities associated with HAART is beyond the scope of this article, selected short-term and long-term significant toxicities will be reviewed. Short-term toxicities that will be discussed include abacavir-induced hypersensitivity reactions, efavirenz-associated central nervous system side effects and rash associated with the non-nucleoside reverse transcriptase inhibitors (NNRTIs) and the protease inhibitor (PI) amprenavir. Several long-term toxicities associated with the nucleoside reverse transcriptase inhibitors (NRTIs) are hypothesized to be due to mitochondrial toxicity. These toxicities include myositis and lactic acidosis with hepatic steatosis, pancreatitis and peripheral neuropathy. Some experts also hypothesize that mitochondrial toxicity is responsible for the lipodystrophy syndrome, which includes hyperglycemia, abnormal fat redistribution and dyslipidemia. Finally, indinavir-associated nephrolithiasis, which may present with either short term or long term use will be discussed. This article will provide the practicing pharmacist with a review of these significant toxicities, the implicated agents, incidence, usual clinical presentation, and recommendations for management.

Evaluating niacin in its various forms

Niacin is available in a number of different formulations according to the speed of drug release. The nomenclature is not standardized, and many names are used interchangeably, creating confusion. Formulations that differ in time of release may have different lipid effects and vary in their adverse reaction profiles. Studies comparing immediate-release with various time-release formulations illustrate these variations. Studies have found immediate-release and the intermediate, or extended-release, once-a-day, prescription form of niacin (i.e., Niaspan), to be essentially equivalent with respect to their efficacy in reducing triglycerides and increasing high-density lipoprotein cholesterol (HDL-C). However, there are fewer side effects and better compliance associated with the latter form.

Lipodystrophy syndrome in HIV infection: what is it, what causes it and how can it be managed?

Since the introduction of HIV-1 protease inhibitors as components of antiretroviral drug combination regimens, the clinical course of HIV disease and opportunistic infections has changed dramatically. Besides the favourable virological, immunological and clinical impact of highly active antiretroviral therapy (HAART), several adverse drug reactions have been observed in patients with HIV receiving therapy. Particularly, peripheral lipodystrophy, central adiposity, dyslipidaemia and insulin resistance have been described with a prevalence of up to 80% in patients infected with HIV, and attributed to almost all components of HAART. Hyperlipidaemia is characterised by an increase of low and very low density lipoprotein-cholesterol as well as apolipoproteins B and E. Several studies strongly suggest that there are either multiple syndromes or a variety of factors inducing different changes that influence the ultimate phenotype. Similarities between HIV-associated fat redistribution and metabolic abnormalities with both inherited lipodystrophies and benign symmetric lipomatosis suggest the pathophysiological involvement of, for example, nuclear factors like lamin A/C and drug-induced mitochondrial dysfunction. Moreover, there is some evidence that cytokines and hormones impair fat and glucose homeostasis in patients with HIV receiving HAART. Three years after the first description of HIV therapy-associated abnormal fat redistribution, there is still an ongoing discussion about the case definition, diagnostic procedure and treatment options for both body shape changes and metabolic disturbances. Regarding therapy, there is a major concern about possible complex pharmacological interactions and overlapping adverse effects between HAART and, for example, lipid-lowering therapy. In addition, the likely contribution of both nucleoside analogue reverse transcriptase inhibitors and protease inhibitors to the development of abnormal fat redistribution in patients with HIV limits options of changing to alternative effective antiretroviral drug combinations. Thus, the occurrence of hyperlipidaemia, maturity onset diabetes mellitus, and marked changes in body habitus resulted in important social and clinical consequences such as an increased risk of atherosclerosis. It also sheds new light on the use of protease inhibitors regarding risk factors for the initial treatment decision. In this article, we discuss the features, pathogenesis and treatment options for body fat redistribution and metabolic disturbances associated with HAART in HIV-1 infection.

Statins and the risk of dementia

BACKGROUND

Dementia affects an estimated 10% of the population older than 65 years. Because vascular and lipid-related mechanisms are thought to have a role in the pathogenesis of Alzheimer's disease and vascular dementia, we did an epidemiological study of the potential effect of HMGCoA (3 hydroxy-3methylglutaryl-coenzyme A) reductase inhibitors (statins) and other lipid-lowering agents on dementia.

METHODS

We used a nested case-control design with information derived from 368 practices which contribute to the UK-based General Practice Research Database. The base study population included three groups of patients age 50 years and older: all individuals who had received lipid-lowering agents (LLAs); all individuals with a clinical diagnosis of untreated hyperlipidaemia; and a randomly selected group of other individuals. From this base population, all cases with a computer-recorded clinical diagnosis of dementia were identified. Each case was matched with up to four controls derived from the base population on age, sex, practice, and index date of case.

FINDINGS

The study encompassed 284 cases with dementia and 1080 controls. Among controls 13% had untreated hyperlipidaemia, 11% were prescribed statins, 7% other LLAs, and 69% had no hyperlipidaemia or LLA exposure. The relative risk estimates of dementia adjusted for age, sex, history of coronary-artery disease, hypertension, coronary-bypass surgery and cerebral ischaemia, smoking and body mass index for individuals with untreated hyperlipidaemia (odds ratio 0.72 [95% CI 0.45-1.14]), or treated with nonstatin LLAs (0.96 [0.47-1.97], was close to 1.0 and not significant compared with people who had no diagnosis of hyperlipidaemia or exposure to other lipid-lowering drugs. The adjusted relative risk for those prescribed statins was 0.29 (0.13-0.63; p=0.002).

INTERPRETATION

Individuals of 50 years and older who were prescribed statins had a substantially lowered risk of developing dementia, independent of the presence or absence of untreated hyperlipidaemia, or exposure to nonstatin LLAs. The available data do not distinguish between Alzheimer's disease and other forms of dementia.

NK-104: a novel synthetic HMG-CoA reductase inhibitor

An elevated level of low-density lipoprotein (LDL)-cholesterol has been recognised as the most important risk factor for coronary artery disease (CAD). Development of the inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) ('statins'), a rate-limiting key enzyme of cholesterol synthesis pathway, has revolutionised the cholesterol-lowering therapy. In the last decade, effective primary and secondary preventive measures have been established in several statin trials to prevent future events of CAD by lowering LDL-cholesterol levels. These results supported the 'lower is better' hypothesis in the relationship between LDL-cholesterol levels and CAD. NK-104 (pitavastatin, previously named as itavastatin or nisvastatin, Kowa Company Ltd., Tokyo) has recently been developed as a new chemically synthesised and powerful statin. On the basis of reported data, the potency of NK-104 is dose-dependent and appears to be equivalent to that of atorvastatin. This new statin is safe and well-tolerated in the treatment of patients with hypercholesterolaemia. The cytochrome P450 system only slightly modifies NK-104, which suggests the clinical advantage of this agent, because the prevalence of clinically significant interactions with a number of other commonly used drugs can be considered to be extremely low. NK-104 can provide a new and potentially superior therapeutic agent when compared with currently available other statins. Randomised controlled clinical trials to assess the long-term effects of this new statin on CAD would be required.

Preliminary guidelines for the evaluation and management of dyslipidemia in adults infected with human immunodeficiency virus and receiving antiretroviral therapy: Recommendations of the Adult AIDS Clinical Trial Group Cardiovascular Disease Focus Group

Dyslipidemia is a prevalent condition that affects patients infected with human immunodeficiency virus (HIV) who are receiving antiretroviral therapy. These preliminary recommendations summarize the current understanding in this area and propose guidelines for management. Existing guidelines for the management of dyslipidemia in the general population formed the general basis for our recommendations. Data on the prevalence and treatment of dyslipidemia of HIV-infected patients, implications of treatment-related dyslipidemia in other chronically ill populations, and pharmacokinetic profiles for the available hypolipidemic agents in non-HIV populations were considered. Although the implications of dyslipidemia in this population are not fully known, the frequency, type, and magnitude of lipid alterations in HIV-infected people are expected to result in increased cardiovascular morbidity. We propose that these patients undergo evaluation and treatment on the basis of existing guidelines for dyslipidemia, with the caveat that avoidance of interactions with antiretroviral agents is paramount.

Cerivastatin: a review of its pharmacological properties and therapeutic efficacy in the management of hypercholesterolaemia

Cerivastatin is an HMG-CoA reductase inhibitor used for the treatment of patients with hypercholesterolaemia. The lipid-lowering efficacy of cerivastatin has been demonstrated in a number of large multicentre, randomised clinical trials. Earlier studies used cerivastatin at relatively low dosages of < or =0.3mg orally once daily, but more recent studies have focused on dosages of 0.4 or 0.8 mg/day currently recommended by the US Food and Drug Administration (FDA). Along with modest improvements in serum levels of triglycerides and high density lipoprotein (HDL)-cholesterol, cerivastatin 0.4 to 0.8 mg/day achieved marked reductions in serum levels of low density lipoprotein (LDL)-cholesterol (33.4 to 44.0%) and total cholesterol (23.0 to 30.8%). These ranges included results of a pivotal North American trial in almost 1000 patients with hypercholesterolaemia. In this 8-week study, US National Cholesterol Education Program (Adult Treatment Panel II) [NCEP] target levels for LDL-cholesterol were achieved in 84% of patients randomised to receive cerivastatin 0.8 mg/day, 73% of those treated with cerivastatin 0.4 mg/day and <10% of placebo recipients. Among patients with baseline serum LDL-cholesterol levels meeting NCEP guidelines for starting pharmacotherapy, 75% achieved target LDL-cholesterol levels with cerivastatin 0.8 mg/day. In 90% of all patients receiving cerivastatin 0.8 mg/day, LDL-cholesterol levels were reduced by 23.9 to 58.4% (6th to 95th percentile). Various subanalyses of clinical trials with cerivastatin indicate that the greatest lipid-lowering response can be expected in women and elderly patients. Cerivastatin is generally well tolerated and adverse events have usually been mild and transient. The overall incidence and nature of adverse events reported with cerivastatin in clinical trials was similar to that of placebo. The most frequent adverse events associated with cerivastatin were headache, GI disturbances, asthenia, pharyngitis and rhinitis. In the large pivotal trial, significant elevations in serum levels of creatine kinase and transaminases were reported in a small proportion of patients receiving cerivastatin but not in placebo recipients. As with other HMG-CoA reductase inhibitors, rare reports of myopathy and rhabdomyolysis have occurred with cerivastatin, although gemfibrozil or cyclosporin were administered concomitantly in most cases. Postmarketing surveillance studies in the US have been performed. In 3 mandated formulary switch conversion studies, cerivastatin was either equivalent or superior to other HMG-CoA reductase inhibitors, including atorvastatin, in reducing serum LDL-cholesterol levels or achieving NCEP target levels. Pharmacoeconomic data with cerivastatin are limited, but analyses conducted to date in the US and Italy suggest that cerivastatin compares favourably with other available HMG-CoA reductase inhibitors in terms of its cost per life-year gained.

CONCLUSION

Cerivastatin is a well tolerated and effective lipid-lowering agent for patients with hypercholesterolaemia. When given at dosages currently recommended by the FDA in the US, cerivastatin achieves marked reductions in serum levels of LDL-cholesterol, reaching NCEP target levels in the vast majority of patients. Thus, cerivastatin provides a useful (and potentially cost effective) alternative to other currently available HMG-CoA reductase inhibitors as a first-line agent for hypercholesterolaemia.

Atherosclerotic renal artery stenosis: surgery, percutaneous transluminal angioplasty, or medical therapy?

Atherosclerotic renal artery stenosis typically occurs in high-risk patients with coexistent vascular disease elsewhere. Patients with atherosclerotic renal artery stenosis may develop progressive renal failure but have a much higher risk of dying of stroke or myocardial infarction than of progressing to endstage renal disease. Recent controlled trials comparing medication to revascularization have shown that only a minority of such patients can expect hypertension cure, whereas trials designed to document the ability of revascularization to prevent progressive renal failure are not yet available. Revascularization should be undertaken in patients with atherosclerotic renal artery stenosis and resistant hypertension or heart failure, and probably in those with rapidly deteriorating renal function or an increase in plasma creatinine levels during angiotensin converting enzyme inhibition. With or without revascularization, medical therapy using antihypertensive agents, statins, and aspirin is necessary in almost all cases.

Atorvastatin upregulates type III nitric oxide synthase in thrombocytes, decreases platelet activation, and protects from cerebral ischemia in normocholesterolemic mice

BACKGROUND AND PURPOSE

Thrombosis superimposed on atherosclerosis causes approximately two thirds of all brain infarctions. We previously demonstrated that statins protect from cerebral ischemia by upregulation of endothelial type III nitric oxide synthase (eNOS), but the downstream mechanisms have not been determined. Therefore, we investigated whether antithrombotic effects contribute to stroke protection by statins.

METHODS

129/SV wild-type and eNOS knockout mice were treated with atorvastatin for 14 days (0.5, 1, and 10 mg/kg). eNOS mRNA from aortas and platelets was measured by reverse-transcriptase polymerase chain reaction. Platelet factor 4 (PF 4) and beta-thromboglobulin (beta-TG) in the plasma were quantified by ELISA. Transient cerebral ischemia was induced by filamentous occlusion of the middle cerebral artery followed by reperfusion.

RESULTS

Stroke volume after 1-hour middle cerebral artery occlusion/23-hour reperfusion was significantly reduced by 38% in atorvastatin-treated animals (10 mg/kg) compared with controls. Serum cholesterol levels were not affected by the treatment. eNOS mRNA was significantly upregulated in a dose-dependent manner in aortas and in thrombocytes of statin-treated mice compared with controls. Moreover, indices of platelet activation in vivo, ie, plasma levels of PF 4 and beta-TG, were dose-dependently downregulated in the treatment group. Surprisingly, atorvastatin-treatment did not influence PF 4 and beta-TG levels in eNOS knockout mice.

CONCLUSIONS

The synthetic 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor atorvastatin upregulates eNOS in thrombocytes, decreases platelet activation in vivo, and protects from cerebral ischemia in normocholesterolemic mice. Antithrombotic and stroke-protective effects of statins are mediated in part by eNOS upregulation. Our results suggest that statins may provide a novel prophylactic treatment strategy independent of serum cholesterol levels.

Coronary artery disease and human immunodeficiency virus infection

Recent reports of myocardial infarctions in young persons infected with human immunodeficiency virus (HIV) who are receiving protease inhibitor therapy have raised concerns about premature coronary artery disease in this population. Endothelial dysfunction, hypercoagulability, hypertriglyceridemia, and abnormal coronary artery pathology were in fact associated with HIV infection prior to the availability of protease inhibitor therapy. Newly recognized risk factors, such as insulin resistance, hypercholesterolemia, and fat redistribution syndrome, may exacerbate underlying atherosclerotic risk for patients receiving protease inhibitors. Data on the incidence of myocardial infarction among these patients are largely limited to case reports but are of concern. Pending the availability of further data, it is prudent to monitor these patients for hyperlipidemia and consider interventions to modify cardiac risk factors.

[Cholesterolemia control in Spain, 2000: a tool for cardiovascular disease prevention]

The document "Cholesterolemia control in Spain, 2000: a tool for cardiovascular disease prevention" reviews the current evidence on cardiovascular disease prevention and the therapeutic advances achieved in recent years, in order to aid risk-based clinical decision-making. Cardiovascular diseases rank as the first cause of death in Spain. Their demographic, health and social impact is increasing and it is likely to continue to do so in the next decades. Appropriate treatment for high blood cholesterol and other major risk factors is crucial in cardiovascular disease prevention. Individual risk stratification is essential to determine follow-up periodicity and treatment. Priorities for the control of cholesterolemia and the consequent cardiovascular risk are based on risk stratification. In primary prevention, the therapeutic objective in high risk patients has been established as LDL-cholesterol < 130 mg/dl. In secondary prevention, drug treatment is indicated when LDL-cholesterol > or = 130 mg/dl and the therapeutic objective is LDL-cholesterol < 100 mg/dl. Statins are first line drugs for treatment of high blood cholesterol. In moderate-severe hypertriglyceridemia or low HDL-cholesterol, fibrates are preferred. In acute coronary syndrome, hypolipemiant treatment, should be started as soon as possible, when indicated. Secondary prevention programmes that continually provide good clinical and risk factor control should be provided to coronary heart disease patients.

Vaccine-induced antibodies inhibit CETP activity in vivo and reduce aortic lesions in a rabbit model of atherosclerosis

Using a vaccine approach, we immunized New Zealand White rabbits with a peptide containing a region of cholesteryl ester transfer protein (CETP) known to be required for neutral lipid transfer function. These rabbits had significantly reduced plasma CETP activity and an altered lipoprotein profile. In a cholesterol-fed rabbit model of atherosclerosis, the fraction of plasma cholesterol in HDL was 42% higher and the fraction of plasma cholesterol in LDL was 24% lower in the CETP-vaccinated group than in the control-vaccinated group. Moreover, the percentage of the aorta surface exhibiting atherosclerotic lesion was 39.6% smaller in the CETP-vaccinated rabbits than in controls. The data reported here demonstrate that CETP activity can be reduced in vivo by vaccination with a peptide derived from CETP and support the concept that inhibition of CETP activity in vivo can be antiatherogenic. In addition, these studies suggest that vaccination against a self-antigen is a viable therapeutic strategy for disease management.

Effects of simvastatin (40 and 80 mg/day) in patients with mixed hyperlipidemia

Mixed hyperlipidemia is characterized by both elevated total cholesterol and triglycerides. It is estimated to account for 10% to 20% of patients with dyslipidemia. This study assessed the lipid-altering efficacy and tolerability of simvastatin 40 and 80 mg/day as monotherapy. One hundred thirty patients (62 women [48%], 24 [16%] with type 2 diabetes mellitus, mean age 53 years) with mixed hyperlipidemia (baseline low-density lipoprotein [LDL] cholesterol 156 mg/dl [mean], and triglycerides 391 mg/dl [median) were randomized in a multicenter, double-masked, placebo-controlled, 3-period, 22-week, balanced crossover study, and received placebo, and simvastatin 40 and 80 mg/day each for 6 weeks. Compared with placebo, simvastatin produced significant (p <0.01) and dose-dependent changes in all lipid and lipoprotein parameters (LDL cholesterol 2.1%, -28.9%, and -35.5%; triglycerides -3.5%, -27.8%, and -33.0%; high-density lipoprotein cholesterol 3.3%, 13.1%, and 15. 7%; apolipoprotein B 3.8%, -23.1%, and -30.6%; and apolipoprotein A-I 4.0%, 8.2%, and 10.5% with placebo, and simvastatin 40 and 80 mg/day, respectively). The changes were consistent in patients with diabetes mellitus. One patient taking simvastatin 80 mg/day had an asymptomatic and reversible increase in hepatic transaminases 3 times above the upper limit of normal. Simvastatin 40 and 80 mg/day is effective in patients with mixed hyperlipidemia across the entire lipid and lipoprotein profile. The reductions in LDL cholesterol and triglycerides are large, significant, and dose dependent. The increase in high-density lipoprotein cholesterol was greater than that observed in patients with hypercholesterolemia, and appears dose dependent.

Peroxisome proliferator-activated receptors in tumorigenesis: targets of tumour promotion and treatment

The peroxisome proliferator-activated receptors (PPAR) are ligand-activated transcription factors. There are three genes that code for the PPAR isoforms: PPARalpha, PPARbeta and PPARgamma. In the present review, studies characterizing the various PPAR isoforms are discussed. Peroxisome proliferator-activated receptor alpha has been implicated in the lipid-lowering effects of the fibrate drugs. Peroxisome proliferator-activated receptor gamma has a clear role in adipocyte differentiation and is therapeutically targeted by the thiazolidinedione drugs for the treatment of type II diabetes. The physiological role of PPARbeta is less well understood but, as described in the present review, recent studies have implicated it with a role in colon cancer. In the present review, particular attention is focused on the role of PPAR in the regulation of expression of proteins associated with cell cycle control and tumorigenesis.

Management of dyslipidemia after coronary artery bypass grafting

The results of serial angiographic studies and intervention trials in patients after coronary artery bypass artery grafting have provided ample evidence that abnormalities of the plasma lipoprotein system are one of the most significant risk factors for a rapid atherosclerotic attrition of saphenous vein grafts. In addition to confirming the well recognized role and contribution of cholesterol-rich LDL or lipoprotein B particles to the progression of atherosclerotic lesions, intervention trials have also provided strong evidence for the atherogenic capacity of some intact and partly delipidized triglyceride-rich very low density lipoprotein and intermediate density lipoprotein (lipoprotein B complex) particles, and the protective effect of some (high density lipoprotein 3) but not all high density lipoprotein particles. Most importantly, those studies have emphasized the need for an early, aggressive treatment of dyslipoproteinemias with pharmacological agents as the most efficient therapeutic approach to delaying, if not preventing, the detrimental effect of atherosclerosis on saphenous vein grafts.

Beneficial effects of weight loss associated with moderate calorie/carbohydrate restriction, and increased proportional intake of protein and unsaturated fat on serum urate and lipoprotein levels in gout: a pilot study

OBJECTIVES

Insulin resistance (IR) has been increasingly implicated in the pathogenesis of gout. The lipoprotein abnormalities described in hyperuricaemic subjects are similar to those associated with IR, and insulin influences renal urate excretion. In this study it was investigated whether dietary measures, reported to be beneficial in IR, have serum uric acid (SU) and lipid lowering effects in gout.

METHODS

Thirteen non-diabetic men (median age 50, range 38-62) were enrolled. Each patient had had at least two gouty attacks during the four months before enrollment. Dietary recommendations consisted of calorie restriction to 6690 kJ (1600 kcal) a day with 40% derived from carbohydrate, 30% from protein, and 30% from fat; replacement of refined carbohydrates with complex ones and saturated fats with mono- and polyunsaturated ones. At onset and after 16 weeks, fasting blood samples were taken for determination of SU, serum cholesterol (C), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), and triglycerides (TGs). Results were expressed as median (SD).

RESULTS

At onset, the body mass index (BMI) was 30.5 (8.1) kg/m(2). Dietary measures resulted in weight loss of 7.7 (5.4) kg (p=0.002) and a decrease in the frequency of monthly attacks from 2.1 (0.8) to 0.6 (0.7) (p=0.002). The SU decreased from 0.57 (0.10) to 0.47 (0.09) mmol/l (p=0.001) and normalised in 7 (58%) of the 12 patients with an initially raised level. Serum cholesterol decreased from 6.0 (1.7) to 4.7 (0. 9) mmol/l (p=0.002), LDL-C from 3.5 (1.2) to 2.7 (0.8) mmol/l (p=0. 004), TGs from 4.7 (4.2) to 1.9 (1.0) mmol/l (p=0.001), and C:HDL-C ratios from 6.7 (1.7) to 5.2 (1.0) (p=0.002). HDL-C levels increased insignificantly. High baseline SU, frequency of attacks, total cholesterol, LDL-C and TG levels, and total C:HDL-C ratios correlated with higher decreases in the respective variables upon dietary intervention (p<0.05).

CONCLUSION

The results suggest that weight reduction associated with a change in proportional macronutrient intake, as recently recommended in IR, is beneficial, reducing the SU levels and dyslipidaemia in gout. Current dietary recommendations for gout may need re-evaluation.

Lipodystrophy syndrome in HIV infection: what is it, what causes it and how can it be managed?

Since the introduction of HIV-1 protease inhibitors as components of antiretroviral drug combination regimens, the clinical course of HIV disease and opportunistic infections has changed dramatically. Besides the favourable virological, immunological and clinical impact of highly active antiretroviral therapy (HAART), several adverse drug reactions have been observed in patients with HIV receiving therapy. Particularly, peripheral lipodystrophy, central adiposity, dyslipidaemia and insulin resistance have been described with a prevalence of up to 80% in patients infected with HIV, and attributed to almost all components of HAART. Hyperlipidaemia is characterised by an increase of low and very low density lipoprotein-cholesterol as well as apolipoproteins B and E. Several studies strongly suggest that there are either multiple syndromes or a variety of factors inducing different changes that influence the ultimate phenotype. Similarities between HIV-associated fat redistribution and metabolic abnormalities with both inherited lipodystrophies and benign symmetric lipomatosis suggest the pathophysiological involvement of, for example, nuclear factors like lamin A/C and drug-induced mitochondrial dysfunction. Moreover, there is some evidence that cytokines and hormones impair fat and glucose homeostasis in patients with HIV receiving HAART. Three years after the first description of HIV therapy-associated abnormal fat redistribution, there is still an ongoing discussion about the case definition, diagnostic procedure and treatment options for both body shape changes and metabolic disturbances. Regarding therapy, there is a major concern about possible complex pharmacological interactions and overlapping adverse effects between HAART and, for example, lipid-lowering therapy. In addition, the likely contribution of both nucleoside analogue reverse transcriptase inhibitors and protease inhibitors to the development of abnormal fat redistribution in patients with HIV limits options of changing to alternative effective antiretroviral drug combinations. Thus, the occurrence of hyperlipidaemia, maturity onset diabetes mellitus, and marked changes in body habitus resulted in important social and clinical consequences such as an increased risk of atherosclerosis. It also sheds new light on the use of protease inhibitors regarding risk factors for the initial treatment decision. In this article, we discuss the features, pathogenesis and treatment options for body fat redistribution and metabolic disturbances associated with HAART in HIV-1 infection.

[Control of cholesterolemia in Spain, 2000. A tool for cardiovascular prevention]

The document "Cholesterolemia Control in Spain, 2000: A Tool for Cardiovascular Disease Prevention" reviews the current evidence on cardiovascular disease prevention and the therapeutic advances achieved in recent years, in order to aid risk-based clinical decision-making. Cardiovascular diseases rank as the first cause of death in Spain. Their demographic, health and social impact is increasing and it is likely to continue to do so in the next decades. Appropriate treatment for high blood cholesterol and other major risk factors is crucial in cardiovascular disease prevention. Individual risk stratification is essential to determine follow-up periodicity and treatment. Priorities for the control of cholesterolemia and the consequent cardiovascular risk are based on risk stratification. In primary prevention, the therapeutic objective in high risk patients has been established as LDL-cholesterol < 130 mg/dl. In secondary prevention, drug treatment is indicated when LDL-cholesterol > or = 130 mg/dl and the therapeutic objective is LDL-cholesterol < 100 mg/dl. Statins are first line drugs for treatment of high blood cholesterol. In moderate-severe hypertriglyceridemia or low HDL-cholesterol, fibrates are preferred. In acute coronary syndrome, hypolipemiant treatment, should be started as soon as possible, when indicated. Secondary prevention programmes that continually provide good clinical and risk factor control should be provided to coronary heart disease patients.

Differential effect of National Cholesterol Education Program (NCEP) Step II diet on HDL cholesterol, its subfractions, and apoprotein A-I levels in hypercholesterolemic women and men after 1 year: the beFIT Study

We previously reported that high density lipoprotein cholesterol (HDL-C) decreases more in hypercholesterolemic (HC) women than in HC men ingesting an National Cholesterol Education Program (NCEP) Step II diet for 6 months. We examined these subjects to determine whether the differential HDL-C reduction persists after 12 months and whether it is associated with decreased HDL(2)-C and apoprotein A-I. Subjects were screened from an industrial workforce and were defined as HC if 2 low density lipoprotein cholesterol measurements were >/=75th percentile or defined as combined hyperlipidemic (CHL) if triglycerides were also >/=75th percentile. The subjects were then taught the NCEP Step II diet in 8 weekly classes and counseled quarterly. Seventy-three HC and 92 CHL women (mean ages 43 and 44 years, respectively) and 112 HC and 106 CHL men (ages 45 and 41 years, respectively) were studied. All groups reported similar total fat (24% to 26% kcal) and saturated fat (7.1% to 7.9% kcal) intakes at 1 year. HDL-C decreased 7.6% in HC women (P<0.01), exceeding the nonsignificant 1.3% decrease in HC men (P=0.000). HDL(2)-C decreased 16.7% in HC women (P<0.01) compared with the nonsignificant 0.5% increase in HC men (P=0.000). In CHL women and men, HDL-C decreased 3.5% and 3.9% (both P<0.01); HDL(2)-C decreased more in women (7.1%, P<0.01) than in men (4.3%, a nonsignificant difference). Apoprotein A-I decreased significantly (5.3%, P<0.01) in HC women only. Plasma triglycerides were unchanged. Low density lipoprotein cholesterol and weight changes were not different among the 4 groups. HDL-C, HDL(2)-C, and apoprotein A-I levels decreased more in HC women than in HC men after following the NCEP Step II diet for 1 year, continuing a trend observed with HDL-C at 6 months. The total HDL-C and HDL(2)-C reductions narrow the baseline differences between men and women by 50%. Whether this reduction impacts women's protection from cardiovascular disease deserves future study. Nonetheless, the results point to sex-based differences in intrahepatic glucose and fatty acid metabolism linked to alterations in HDL formation and removal.