Effects of statins on high-density lipoproteins: a potential contribution to cardiovascular benefit.

PURPOSE: The objective was to systematically review clinical trial data on the effects of statins on high-density lipoproteins (HDL) and to examine the possibility that this provides cardiovascular benefits in addition to those derived from reductions in low-density lipoproteins (LDL). METHODS: The PubMed database was searched for publications describing clinical trials of atorvastatin, pravastatin, rosuvastatin, and simvastatin. On the basis of predefined criteria, 103 were selected for review. RESULTS: Compared with placebo, statins raise HDL, measured as HDL-cholesterol (HDL-C) and apolipoprotein A-I (apo A-I); these elevations are maintained in the long-term. In hypercholesterolemia, HDL-C is raised by approximately 4% to 10%. The percentage changes are greater in patients with low baseline levels, including those with the common combination of high triglycerides (TG) and low HDL-C. These effects do not appear to be dose-related although there is evidence that, with the exception of atorvastatin, the changes in HDL-C are proportional to reductions in apo B-containing lipoproteins. The most likely explanation is a reduced rate of cholesteryl ester transfer protein (CETP)-mediated flow of cholesterol from HDL. There is some evidence that the statin effects on HDL reduce progression of atherosclerosis and risk of cardiovascular disease independently of reductions in LDL. CONCLUSION: Statins cause modest increases in HDL-C and apo A-I probably mediated by reductions in CETP activity. It is plausible that such changes independently contribute to the cardiovascular benefits of the statin class but more studies are needed to further explore this possibility.

Comparison of the effects of high doses of rosuvastatin versus atorvastatin on the subpopulations of high-density lipoproteins.

Atorvastatin and rosuvastatin are both highly effective in decreasing low-density lipoprotein cholesterol and triglyceride levels. However, rosuvastatin was shown to be more effective in increasing high-density lipoprotein (HDL) cholesterol levels. The purpose of the study is to compare the effects of daily doses of rosuvastatin 40 mg with atorvastatin 80 mg during a 6-week period on HDL subpopulations in 306 hyperlipidemic men and women. We previously showed that increased levels of large alpha-1 and alpha-2 HDLs decrease the risk of coronary heart disease and protect against progression of coronary atherosclerosis (superior to HDL cholesterol). In this study, both statins caused significant increases in large alpha-1 (p <0.001) and alpha-2 (p <0.001 for rosuvastatin, p <0.05 for atorvastatin) and significant (p <0.001) decreases in small pre-beta-1 HDL levels; however, increases in the 2 large HDL particles were significantly higher for rosuvastatin than atorvastatin (alpha-1, 24% vs 12%; alpha-2, 13% vs 4%; p <0.001). Statin-induced increases in alpha-1 and alpha-2 correlated with increases in HDL cholesterol, whereas decreases in pre-beta-1 were associated with decreases in triglycerides. In subjects with low HDL cholesterol (<40 mg/dl for men, <50 mg/dl for women, n = 99), increases in alpha-1 were 32% versus 11%, and in alpha-2, 21% versus 5% for rosuvastatin and atorvastatin, respectively. In conclusion, our data show that both statins, given at their maximal doses, favorably alter the HDL subpopulation profile, but also that rosuvastatin is significantly more effective in this regard than atorvastatin.

Effect of short-term rosuvastatin treatment on estimated glomerular filtration rate.

To define the effect of short-term rosuvastatin treatment on the estimated glomerular filtration rate (eGFR), the database of controlled clinical trials in the Rosuvastatin Clinical Development Program was reviewed. Thirteen studies comprising 3,956 rosuvastatin-treated patients were selected based on a serum creatinine measurement at 6 or 8 weeks after initiation of rosuvastatin treatment, randomization to approved and marketed rosuvastatin doses (5 to 40 mg), and unchanged rosuvastatin dose from treatment initiation (baseline) through 6 to 8 weeks of treatment. eGFR was determined with the Modification of Diet in Renal Disease formula. eGFR significantly increased for each dose of rosuvastatin individually and for all doses combined compared with baseline (range +0.9 to +3.2 ml/min/1.73 m2). Further analysis of 5 blinded, placebo-controlled trials comprising 525 patients showed an increase in eGFR of +0.8 ml/min/1.73 m2 (95% confidence interval +0.1 to +1.5) for all rosuvastatin-treated patients, which was significantly different from baseline (p <0.04) and from a change of -1.5 ml/min/1.73 m2 in the placebo-treated patients (95% confidence interval -2.5 to -0.5, p <0.001). The increase in eGFR for rosuvastatin-treated patients was consistent across all major demographic and clinical subgroups of interest, including patients with baseline proteinuria, baseline eGFR <60 ml/min/1.73 m2, and in patients with hypertension and/or diabetes. In conclusion, these results are consistent with previous rosuvastatin studies that showed an upward trend in eGFR with long-term treatment (> or =96 weeks) and with the hypothesis that statins may have pleiotropic mechanisms of action that include beneficial renal effects.

Inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase reduce receptor-mediated endocytosis in opossum kidney cells.

Renal proximal tubule cells are responsible for the reabsorption of proteins that are present in the tubular lumen. This occurs by receptor-mediated endocytosis, a process that has a requirement for some GTP-binding proteins. Statins are inhibitors of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase used for the therapeutic reduction of cholesterol-containing plasma lipoproteins. However, they can also reduce intracellular levels of isoprenoid pyrophosphates that are derived from the product of the enzyme, mevalonate, and are required for the prenylation and normal function of GTP-binding proteins. The hypothesis that inhibition of HMG-CoA reductase in renal proximal tubule cells could reduce receptor mediated-endocytosis was therefore tested. Five different statins inhibited the uptake of FITC-labeled albumin by the proximal tubule-derived opossum kidney cell line in a dose-dependent manner and in the absence of cytotoxicity. The reduction in albumin uptake was related to the degree of inhibition of HMG-CoA reductase. Simvastatin (e.g., statin) inhibited receptor-mediated endocytosis of both FITC-albumin and FITC-beta(2)-microglobulin to similar extents but without altering the binding of albumin to the cell surface. The effect on albumin endocytosis was prevented by mevalonate and by the isoprenoid geranylgeranyl pyrophosphate but not by cholesterol. Finally, evidence that the inhibitory effect of statins on endocytosis of proteins may be caused by reduced prenylation and thereby decreased function of one or more GTP-binding proteins is provided. These data establish the possibility in principle that inhibition of HMG-CoA reductase by statins in proximal tubule cells may reduce tubular protein reabsorption.

Phenotype-dependent and -independent actions of rosuvastatin on atherogenic lipoprotein subfractions in hyperlipidaemia.

This randomised, double-blind, placebo-controlled crossover study evaluated the effects of rosuvastatin (40 mg/day for 8 weeks) on atherogenic apolipoprotein B-containing lipoprotein subfractions. Subjects, recruited based on raised plasma triglyceride (TG) or low-density lipoprotein cholesterol (LDL-C), were divided into normotriglyceridaemic (NTG, n = 13; TG < 2.0 mmol/l) and hypertriglyceridaemic (HTG, n = 16; TG > or = 2.0 mmol/l) groups. Similar reductions on rosuvastatin were observed for both groups in LDL-C (NTG -60%; HTG -56%), apoB (both -49%), intermediate-density lipoprotein (NTG -57%; HTG -54%) and LDL circulating mass (NTG -52%, HTG -58%) (all P < 0.001 versus placebo), i.e., these changes were phenotype independent. Phenotype dependency in response was observed in HTG relative to NTG in concentration of small dense LDL (LDL-III) (NTG -44%, P = NS; HTG -69%, P < 0.001), very-low-density lipoprotein1 (NTG -18%, P = NS; HTG 46%, P < 0.01), and remnant-like particle cholesterol (NTG -31%, P = NS; HTG -48%, P < 0.05). Rosuvastatin reduced cholesteryl ester transfer protein (CETP) by 33% in NTG and 37% in HTG (both P < 0.001); a reduction in cholesteryl ester transfer activity (-59%, P < 0.001) was observed in HTG only. Rosuvastatin therefore, in addition to lowering LDL and apoB-concentrations, largely corrected the TG and LDL abnormalities in subjects who had the propensity to develop the atherogenic lipoprotein phenotype.

Comparative pharmacology of rosuvastatin.

The major therapeutic action of statin drugs is reduction in levels of circulating atherogenic lipoproteins as a result of inhibition of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase mainly in the liver. The magnitude of reduction of atherogenic lipoproteins differs among various statins. It is suggested that an ideal statin would maximize the pharmacodynamic activity in the liver and minimize the inhibitory activity outside the liver, particularly in some vulnerable tissues, such as skeletal muscle. An additional advantage would be a low risk of undesirable interactions with other drugs. Compared with other statins, rosuvastatin has been found to be a relatively potent inhibitor of HMG-CoA reductase and to have a high degree of selectivity for effect in liver cells compared with a range of non-hepatic cells, including cultured human skeletal muscle cells. In addition, rosuvastatin undergoes relatively little metabolism by the hepatic CYP system; it has a moderate degree of systemic bioavailability and a relatively long elimination half-life. On the basis of these criteria, rosuvastatin represents a step forward in efforts to optimize the pharmacologic properties of the statin class.

New dimension of statin action on ApoB atherogenicity.

Newer, more effective statins are powerful agents for reducing elevated levels of low-density lipoprotein (LDL) cholesterol and thereby lowering the risk of coronary heart disease (CHD) and related adverse events. Although LDL remains the primary target of therapy for reducing CHD risk, increased interest is focusing on apolipoprotein B (apoB)-containing lipoprotein subfractions--particularly very-low-density lipoprotein (VLDL). VLDL remnants, and intermediate-density lipoproteins (IDL)--as secondary targets of therapy. Elevated apoB is known to be an important risk factor for CHD, and dysregulation of the metabolism of apoB-containing lipoproteins is involved in the progression of atherosclerosis. Statins reduce circulating concentrations of atherogenic apoB-containing lipoproteins by decreasing the production of VLDL in the liver and, thus, the production of VLDL remnants and LDL. Statins also increase the clearance of these particles through upregulation of LDL receptors in the liver. Efforts to develop statins with enhanced lipid-modifying properties are ongoing. The optimal statin would offer a high degree of inhibition of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, a prolonged duration of action, hepatic selectivity for maximal upregulation of LDL receptors, and a low potential for drug-drug interactions. Recent studies have shown that rosuvastatin, a new agent in this class, demonstrates these qualities. Rosuvastatin is a highly effective inhibitor of HMG-CoA reductase, is relatively nonlipophilic, has a half-life of approximately 20 h, exhibits hepatic selectivity, has little systemic availability, and has a low potential for drug-drug interactions because of its limited degree of metabolism by the cytochrome P450 system. A recent double-blind, crossover study revealed that treatment with rosuvastatin resulted in marked reductions in apoB-containing lipoproteins in patients with type IIa or IIb dyslipidemia. By reducing the number of atherogenic lipoprotein particles, rosuvastatin decreases the atherosclerotic burden in hyperlipidemic patients at high risk for CHD and related adverse outcomes.

Rosuvastatin: a highly effective new HMG-CoA reductase inhibitor.

Rosuvastatin, a new statin, has been shown to possess a number of advantageous pharmacological properties, including enhanced HMG-CoA reductase binding characteristics, relative hydrophilicity, and selective uptake into/activity in hepatic cells. Cytochrome p450 (CYP) metabolism of rosuvastatin appears to be minimal and is principally mediated by the 2C9 enzyme, with little involvement of 3A4; this finding is consistent with the absence of clinically significant pharmacokinetic drug-drug interactions between rosuvastatin and other drugs known to inhibit CYP enzymes. Dose-ranging studies in hypercholesterolemic patients demonstrated dose-dependent effects in reducing low-density lipoprotein cholesterol (LDL-C) (up to 63%), total cholesterol, and apolipoprotein (apo) B across a 1- to 40-mg dose range and a significant 8.4% additional reduction in LDL-C, compared with atorvastatin, across the dose ranges of the two agents. Rosuvastatin has also been shown to be highly effective in reducing LDL-C, increasing high-density lipoprotein cholesterol (HDL-C), and producing favorable modifications of other elements of the atherogenic lipid profile in a wide range of dyslipidemic patients. In patients with mild to moderate hypercholesterolemia, rosuvastatin has been shown to produce large decreases in LDL-C at starting doses, thus reducing the need for subsequent dose titration, and to allow greater percentages of patients to attain lipid goals, compared with available statins. The substantial LDL-C reductions and improvements in other lipid measures with rosuvastatin treatment should facilitate achievement of lipid goals and reduce the requirement for combination therapy in patients with severe hypercholesterolemia. In addition, rosuvastatin's effects in reducing triglycerides, triglyceride-containing lipoproteins, non-HDL-C, and LDL-C and increasing HDL-C in patients with mixed dyslipidemia or elevated triglycerides should be of considerable value in enabling achievement of LDL-C and non-HDL-C goals in the numerous patients with combined dyslipidemias or metabolic syndrome who require lipid-lowering therapy. Rosuvastatin is well tolerated alone, and in combination with fenofibrate, extended-release niacin, and cholestyramine, and has a safety profile similar to that of currently marketed statins. A large, long-term clinical trials program is under way to investigate the effects of rosuvastatin on atherosclerosis and cardiovascular morbidity and mortality.

Optimizing the pharmacology of statins: characteristics of rosuvastatin.

Rosuvastatin (Crestor, AstraZeneca) is a new synthetic statin that exhibits a number of highly desirable pharmacologic characteristics. The drug has a high affinity for the active site of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and exhibits greater potency in inhibiting enzyme activity and cholesterol synthesis in vitro than other statins. The effects of rosuvastatin are selective for hepatic cells, and there is minimal uptake of the drug by nonhepatic tissues. The vast majority of biologic activity of the drug is associated with the parent compound, which does not appear to undergo extensive metabolism. Hepatic metabolism appears to be minimal, and there is little evidence of metabolic interaction with cytochrome P450 3A4. In an early-phase study, rosuvastatin produced large and dose-related decreases in low-density lipoprotein (LDL) cholesterol of up to 65% in hypercholesterolemic patients. Rosuvastatin should constitute an important addition to current lipid-lowering interventions.