Dose-dependent regulation of high-density lipoprotein metabolism with rosuvastatin in the metabolic syndrome

Pitavastatin treatment remodels the HDL subclass lipidome and proteome in hypertriglyceridemia

HDL particles vary in lipidome and proteome, which dictate their individual physicochemical properties, metabolism, and biological activities. HDL dysmetabolism in nondiabetic hypertriglyceridemia (HTG) involves subnormal HDL-cholesterol and apoAI levels. Metabolic anomalies may impact the qualitative features of both the HDL lipidome and proteome. Whether particle content of bioactive lipids and proteins may differentiate HDL subclasses (HDL2b, 2a, 3a, 3b, and 3c) in HTG is unknown. Moreover, little is known of the effect of statin treatment on the proteolipidome of hypertriglyceridemic HDL and its subclasses. Nondiabetic, obese, HTG males (n = 12) received pitavastatin calcium (4 mg/day) for 180 days in a single-phase, unblinded study. ApoB-containing lipoproteins were normalized poststatin. Individual proteolipidomes of density-defined HDL subclasses were characterized prestatin and poststatin. At baseline, dense HDL3c was distinguished by marked protein diversity and peak abundance of surface lysophospholipids, amphipathic diacylglycerol and dihydroceramide, and core cholesteryl ester and triacylglycerol, (normalized to mol phosphatidylcholine), whereas light HDL2b showed peak abundance of free cholesterol, sphingomyelin, glycosphingolipids (monohexosylceramide, dihexosylceramide, trihexosylceramide, and anionic GM3), thereby arguing for differential lipid transport and metabolism between subclasses. Poststatin, bioactive lysophospholipid (lysophosphatidylcholine, lysoalkylphosphatidylcholine, lysophosphatidylethanolamine, and lysophosphatidylinositol) cargo was preferentially depleted in HDL3c. By contrast, baseline lipidomic profiles of ceramide, dihydroceramide and related glycosphingolipids, and GM3/phosphatidylcholine were maintained across particle subclasses. All subclasses were depleted in triacylglycerol and diacylglycerol/phosphatidylcholine. The abundance of apolipoproteins CI, CII, CIV, and M diminished in the HDL proteome. Statin treatment principally impacts metabolic remodeling of the abnormal lipidome of HDL particle subclasses in nondiabetic HTG, with lesser effects on the proteome.

High-Density Lipoprotein Alterations in Type 2 Diabetes and Obesity

Alterations affecting high-density lipoproteins (HDLs) are one of the various abnormalities observed in dyslipidemia in type 2 diabetes mellitus (T2DM) and obesity. Kinetic studies have demonstrated that the catabolism of HDL particles is accelerated. Both the size and the lipidome and proteome of HDL particles are significantly modified, which likely contributes to some of the functional defects of HDLs. Studies on cholesterol efflux capacity have yielded heterogeneous results, ranging from a defect to an improvement. Several studies indicate that HDLs are less able to inhibit the nuclear factor kappa-B (NF-κB) proinflammatory pathway, and subsequently, the adhesion of monocytes on endothelium and their recruitment into the subendothelial space. In addition, the antioxidative function of HDL particles is diminished, thus facilitating the deleterious effects of oxidized low-density lipoproteins on vasculature. Lastly, the HDL-induced activation of endothelial nitric oxide synthase is less effective in T2DM and metabolic syndrome, contributing to several HDL functional defects, such as an impaired capacity to promote vasodilatation and endothelium repair, and difficulty counteracting the production of reactive oxygen species and inflammation.

Unravelling lipoprotein metabolism with stable isotopes: tracing the flow

Dysregulated lipoprotein metabolism is a major cause of atherosclerotic cardiovascular disease (ASCVD). Use of stable isotope tracers and compartmental modelling have provided deeper understanding of the mechanisms underlying lipid disorders in patients at high risk of ASCVD, including familial hypercholesterolemia (FH), elevated lipoprotein(a) [Lp(a)] and metabolic syndrome (MetS). In patients with FH, deficiency in low-density lipoprotein (LDL) receptor activity not only impairs the catabolism of LDL, but also induces hepatic overproduction and decreases catabolism of triglyceride-rich lipoproteins (TRLs). Patients with elevated Lp(a) are characterized by increased hepatic secretion of Lp(a) particles. Atherogenic dyslipidemia in MetS patients relates to a combination of overproduction of very-low density lipoprotein-apolipoprotein (apo) B-100, decreased catabolism of apoB-100-containing particles, and increased catabolism of high-density lipoprotein-apoA-I particles, as well as to impaired clearance of TRLs in the postprandial state. Kinetic studies show that weight loss, fish oils, statins and fibrates have complementary modes of action that correct atherogenic dyslipidemia. Defining the kinetic mechanisms of action of proprotein convertase subtilisin/kexin type 9 and angiopoietin-like 3 inhibitors on lipid and lipoprotein mechanism in dyslipidemic subjects will further our understanding of these therapies in decreasing the development of ASCVD. "Everything changes but change itself. Everything flows and nothing remains the same... You cannot step twice into the same river, for other waters and yet others go flowing ever on." Heraclitus (c.535- c. 475 BCE).

Influence of rosuvastatin dose on total fatty acids and free fatty acids in plasma: Correlations with lipids involved in cholesterol homeostasis

This study investigates for the first time the influence of four doses of rosuvastatin on total fatty acids (TFA) and free fatty acids (FFA) in human plasma and correlates their changes in concentration with changes in the concentration of other lipids involved in cholesterol homeostasis.This study was a placebo-controlled, randomized, double-blind, crossover experiment. The study used a single group of 16 men and consisted of 5 treatment periods lasting 4 weeks each with placebo and 4 doses of rosuvastatin (5, 10, 20, and 40 mg). Each subject changed 5 medical treatments and received in each new treatment different tablets of rosuvastatin or placebo compared to those taken in previous treatments, in a random order. Between treatment periods there was a wash-out period of 2 weeks, without treatment.Changes in TFA and FFA were significant compared to placebo and between different doses of rosuvastatin. We found a continuous logarithmic decrease in levels of TFA, FFA, low-density lipoprotein (LDL)-cholesterol, total cholesterol, triglycerides, phospholipids, and apolipoprotein B-100, and a continuous increase in levels of high-density lipoprotein (HDL)-cholesterol and apolipoprotein A-1 by increases the dose of rosuvastatin. Analysis of the correlation of TFA and FFA with the main lipids and lipoproteins in cholesterol homeostasis indicated a linear regression with high correlation coefficients and all P-values were less than .05 level.The concentrations of TFA and FFA are significantly influenced by the dose of rosuvastatin. They are strongly correlated with those of other lipids and lipoproteins involved in cholesterol homeostasis. The mechanisms of cholesterol homeostasis regulation are involved in changing the concentrations of TFA and FFA.

ApoA-II HDL Catabolism and Its Relationships With the Kinetics of ApoA-I HDL and of VLDL1, in Abdominal Obesity

We study the associations between apoA-II fractional catabolic rate (FCR) and the kinetics of VLDL subspecies and apoA-I and show that, in abdominally obese individuals, apoA-II FCR is positively and independently associated with both apoA-I FCR and VLDL1-TG indirect FCR.

Rosuvastatin Enhances the Catabolism of LDL apoB-100 in Subjects with Combined Hyperlipidemia in a Dose Dependent Manner

Dose-associated effects of rosuvastatin on the metabolism of apolipoprotein (apo) B-100 in triacylglycerol rich lipoprotein (TRL, d < 1.019 g/ml) and low density lipoprotein (LDL) and of apoA-I in high density lipoprotein (HDL) were assessed in subjects with combined hyperlipidemia. Our primary hypothesis was that maximal dose rosuvastatin would decrease the apoB-100 production rate (PR), as well as increase apoB-100 fractional catabolic rate (FCR). Eight subjects received placebo, rosuvastatin 5 mg/day, and rosuvastatin 40 mg/day for 8 weeks each in sequential order. The kinetics of apoB-100 in TRL and LDL and apoA-I in HDL were determined at the end of each phase using stable isotope methodology, gas chromatography-mass spectrometry, and multicompartmental modeling. Rosuvastatin at 5 and 40 mg/day decreased LDL cholesterol by 44 and 54% (both P < 0.0001), triacylglycerol by 14% (ns) and 35% (P < 0.01), apoB by 30 and 36% (both P < 0.0001), respectively, and had no significant effects on HDL cholesterol or apoA-I levels. Significant decreases in plasma markers of cholesterol synthesis and increases in cholesterol absorption markers were observed. Rosuvastatin 5 and 40 mg/day increased TRL apoB-100 FCR by 36 and 46% (both ns) and LDL apoB-100 by 63 and 102% (both P < 0.05), respectively. HDL apoA-I PR increased with low dose rosuvastatin (12%, P < 0.05) but not with maximal dose rosuvastatin. Neither rosuvastatin dose altered apoB-100 PR or HDL apoA-I FCR. Our data indicate that maximal dose rosuvastatin treatment in subjects with combined hyperlipidemia resulted in significant increases in the catabolism of LDL apoB-100, with no significant effects on apoB-100 production or HDL apoA-I kinetics.

The metabolic and pharmacologic bases for treating atherogenic dyslipidaemia

Dyslipoproteinaemia is a cardinal feature of the metabolic syndrome that accelerates atherosclerosis. It is characterized by high plasma concentrations of triglyceride-rich and apolipoprotein (apo) B-containing lipoproteins, with depressed high-density lipoprotein (HDL) and increased small dense low-density lipoprotein (LDL) particle concentrations. Dysregulation of lipoprotein metabolism in the metabolic syndrome may be due to a combination of overproduction of very-low density lipoprotein (VLDL) apoB, decreased catabolism of apoB-containing particles, and increased catabolism of HDL apoA-I particles. These abnormalities are due to a global metabolic effect of insulin resistance and visceral obesity. Lifestyle modifications (dietary restriction and increased exercise) and pharmacological treatments favourably alter lipoprotein transport by decreasing the hepatic secretion of VLDL-apoB and the catabolism of HDL apoA-I, as well as by increasing the clearance of LDL-apoB. The safety and tolerability of combination drug therapy based on statins is important and merits further investigation. There are several pipeline therapies for correcting triglyceride-rich lipoprotein and HDL metabolism. However, their clinical efficacy, safety and cost-effectiveness remain to be demonstrated.

Rosuvastatin improves plaque morphology in cerebral embolism patients with normal low-density lipoprotein and severe aortic arch plaque

The effect of rosuvastatin was investigated on complicated aortic arch plaque (CAP) morphology and lipid profiles in acute cerebral embolism (CE) patients with normal low-density lipoprotein-cholesterol (LDL-c) levels. Transesophageal echocardiography (TEE) studies were performed in 56 consecutive CE patients with LDL-c less than 140 mg/dL who were not taking lipid-lowering agents at baseline. CAP observed by TEE was defined as the presence of greater than 4-mm diameter, ulcerated, or mobile aortic plaque. Patients were divided into those with CAP versus without CAP (group A, n=24, age 69±8 years) and without CAP (group B, n=32, age 62±10 years). Of the 24 group A patients, 18 received 5 mg/d of rosuvastatin for 6 months and had follow-up TEE studies. In Group A, the baseline values of high-density lipoprotein-cholesterol (HDL-c) and apolipoprotein A-1 (ApoA-1) were significantly lower than in Group B (44±15 versus 55±15 mg/dL, P=.0059; 103±19 versus 137±25 mg/dL, P=.0006, respectively) and age and serum high-sensitivity C-reactive protein concentration were significantly higher (69±8 vs. 62±10 years, P=.0080; 2.34±3.05 vs. 0.67±1.00 mg/dL, P=.0054, respectively). By multivariate logistic regression analysis, ApoA-1 was shown to be an independent predictor of CAP (odds ratio=.894, 95% confidence intervals .800-.996, P=.0483). In the 18 group A patients receiving rosuvastatin for 6 months, aortic arch plaque diameter and serum LDL-c were significantly decreased (5.8±2.2 to 5.1±2.1 mm, P=.0377; 110±23 to 81±23 mg/dL, P=.0008, respectively), whereas serum HDL-c and ApoA-1 concentrations were significantly increased (42±8 to 52±9 mg/dL, P=.0002; 109±22 to 135±15 mg/dL, P=.0002, respectively). Plaques were morphologically improved in 11 patients, unchanged in 6, and worsened in 1. These data suggest that rosuvastatin improves plaque morphology concomitant with improving lipid profiles in CE patients with normal LDL-c levels.

Statins and lipid metabolism: an update

PURPOSE OF REVIEW

The reduction in cardiovascular disease risk by statins is well established. This risk reduction has mostly been attributed to decreases in plasma LDL cholesterol and other pleiotropic effects of statins. Emerging evidence indicates that statins exert multiple effects on lipoprotein metabolism, including chylomicrons and HDLs.

RECENT FINDINGS

Kinetic and in-vitro studies have documented that the effects of statins on the metabolism of different lipoproteins are for the most part the direct consequence of cholesterol biosynthesis inhibition and the subsequent change in transcription factors and cell signaling, regulating different aspects of lipoprotein metabolism. Differences in pharmacokinetics and pharmacodynamics among statins lead to diverse biological outcomes.

SUMMARY

The current review summarizes recent experimental evidence highlighting the different effects of statins on cellular pathways regulating gene expression. Understanding the basic mechanisms by which different statins regulate lipoprotein metabolism will lead to improved strategies for the prevention and treatment of specific lipoprotein disorders.

Effect of rosuvastatin monotherapy or in combination with fenofibrate or ω-3 fatty acids on lipoprotein subfraction profile in patients with mixed dyslipidaemia and metabolic syndrome

BACKGROUND

Raised triglycerides (TG), decreased high-density lipoprotein cholesterol (HDL-C) levels and a predominance of small dense low density lipoproteins (sdLDL) are characteristics of the metabolic syndrome (MetS).

OBJECTIVE

To compare the effect of high-dose rosuvastatin monotherapy with moderate dosing combined with fenofibrate or ω-3 fatty acids on the lipoprotein subfraction profile in patients with mixed dyslipidaemia and MetS.

METHODS

We previously randomised patients with low-density lipoprotein cholesterol (LDL-C) > 160 and TG > 200 mg/dl to rosuvastatin monotherapy 40 mg/day (R group, n = 30) or rosuvastatin 10 mg/day combined with fenofibrate 200 mg/day (RF group, n = 30) or ω-3 fatty acids 2 g/day (Rω group, n = 30). In the present study, only patients with MetS were included (24, 23 and 24 in the R, RF and Rω groups respectively). At baseline and after 12 weeks of treatment, the lipoprotein subfraction profile was determined by polyacrylamide 3% gel electrophoresis.

RESULTS

The mean LDL size was significantly increased in all groups. This change was more prominent with RF than with other treatments in parallel with its greater hypotriglyceridemic capacity (p < 0.05 compared with R and Rω). A decrease in insulin resistance by RF was also noted. Only RF significantly raised HDL-C levels (by 7.7%, p < 0.05) by increasing the cholesterol of small HDL particles. The cholesterol of larger HDL subclasses was significantly increased by R and Rω.

CONCLUSIONS

All regimens increased mean LDL size; RF was the most effective. A differential effect of treatments was noted on the HDL subfraction profile.

Rosuvastatin-induced high-density lipoprotein changes in patients who underwent percutaneous coronary intervention for non-ST-segment elevation acute coronary syndrome

BACKGROUND

Clinical significance of statin-induced high-density lipoprotein cholesterol (HDL-C) changes is not well known. We investigated the factors affecting rosuvastatin-induced HDL-C changes and their correlation with 12-month major adverse cardiovascular events (MACE) in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) and percutaneous coronary intervention (PCI).

MATERIALS AND METHODS

We analyzed 556 consecutive NSTE-ACS patients who underwent PCI and received rosuvastatin 10mg before discharge. We measured serum lipids, including total cholesterol, triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), and HDL-C at baseline and at 4 weeks. The relationship between on-treatment lipid levels, baseline lipid levels, and 12-month MACE was assessed.

RESULTS

Rosuvastatin treatment increased the mean HDL-C concentration by 1.1 ± 9.8 mg/dl (4.3 ± 23.0%). HDL-C was increased in 312 patients (56.1%), but decreased in 244 patients (43.9%) after statin treatment. Changes in HDL-C during first month were inversely correlated with baseline HDL-C levels (r=-0.379, p<0.001). The patients with increased HDL-C showed higher baseline TG levels but lower on-treatment TG levels. Changes in TG were correlated with changes in HDL-C (r=-0.212, p<0.001). The incidence of 12-month MACE according to changes in HDL-C was similar between the two groups (11.9% vs. 12.3%, p=0.875). Multivariate analysis revealed that baseline HDL-C level was the only significant predictor of rosuvastatin-induced HDL-C changes.

CONCLUSION

Baseline HDL-C concentration was an independent predictor of rosuvastatin-induced HDL-C changes. Statin-induced HDL-C changes did not predict 12-month MACE in patients with NSTE-ACS.

Rosuvastatin does not affect human apolipoprotein A-I expression in genetically modified mice: a clue to the disputed effect of statins on HDL

BACKGROUND AND PURPOSE

Besides a significant reduction of low-density lipoprotein (LDL) cholesterol, statins moderately increase high-density lipoprotein (HDL) levels. In vitro studies have indicated that this effect may be the result of an increased expression of apolipoprotein (apo)A-I, the main protein component of HDL. The aim of the present study was to investigate in vivo the effect of rosuvastatin on apoA-I expression and secretion in a transgenic mouse model for human apoA-I.

EXPERIMENTAL APPROACH

Human apoA-I transgenic mice were treated for 28 days with 5, 10 or 20 mg·kg(-1) ·day(-1) of rosuvastatin, the most effective statin in raising HDL levels. Possible changes of apoA-I expression by treatment were investigated by quantitative real-time RT-PCR on RNA extracted from mouse livers. The human apoA-I secretion rate was determined in primary hepatocytes isolated from transgenic mice from each group after treatment.

KEY RESULTS

Rosuvastatin treatment with 5 and 10 mg·kg(-1) ·day(-1) did not affect apoA-I plasma levels, whereas a significant decrease was observed in mice treated with 20 mg·kg(-1) ·day(-1) of rosuvastatin (-16%, P < 0.01). Neither relative hepatic mRNA concentrations of apoA-I nor apoA-I secretion rates from primary hepatocytes were influenced by rosuvastatin treatment at each tested dose.

CONCLUSIONS AND IMPLICATIONS

In human apoA-I transgenic mice, rosuvastatin treatment does not increase either apoA-I transcription and hepatic secretion, or apoA-I plasma levels. These results support the hypothesis that other mechanisms may account for the observed HDL increase induced by statin therapy in humans.

Clinical role of apolipoproteins A and B

The assessment and correction of the traditional parameters of atherogenic dyslipidemia are important, but not exclusive methods in the management of atherosclerosis, including coronary artery atherosclerosis. More accurate diagnostic and therapeutic assessment requires the measurement of apolipoprotein (Apo) A, ApoB, and their ratio.Lower ApoB/ApoAI ratio values denote lower levels of cardiovascular risk.

Circulating plasma cholesteryl ester transfer protein activity and blood pressure tracking in the community

OBJECTIVE

Clinical trials using cholesteryl ester transfer protein (CETP) inhibitors to raise high-density lipoprotein cholesterol (HDL-C) concentrations reported an 'off-target' blood pressure (BP) raising effect. We evaluated the relations of baseline plasma CETP activity and longitudinal BP change.

METHODS AND RESULTS

One thousand, three hundred and seven Framingham Study participants free of cardiovascular disease attending consecutive examinations 4 years apart (mean age 48 years) had baseline plasma CETP activity related to change in BP over the 4-year interval, adjusting for standard risk factors. Systolic BP increased [median +2 mmHg, 95% confidence interval (CI) -16,+23 mmHg], whereas diastolic BP decreased (median -3 mmHg, 95% CI -15,+11 mmHg). Plasma CETP activity was not related to change in diastolic BP, but was inversely related to change in systolic BP that was borderline significant (P=0.09). On multivariable analyses, plasma CETP activity was inversely related to change in pulse pressure (PP; beta per SD increment= -0.71 mmHg, P=0.005). When dichotomized at the median, plasma CETP activity above the median was associated with a 1 mmHg lower PP on follow-up (P=0.045).

CONCLUSION

Decreasing plasma CETP activity was modestly related to increasing PP on follow-up in our community-based sample, suggesting that inhibition of intrinsic CETP activity itself is likely associated with minimal changes in BP.

Dyslipidaemia in the metabolic syndrome and type 2 diabetes: pathogenesis, priorities, pharmacotherapies

IMPORTANCE OF THE FIELD

Dyslipoproteinaemia is a cardinal feature of the metabolic syndrome that accelerates atherosclerosis. It is usually characterized by high plasma concentrations of triglyceride-rich and apolipoprotein B (apoB)-containing lipoproteins, with depressed concentrations of high-density lipoprotein (HDL). Drug interventions are essential for normalizing metabolic dyslipidaemia.

AREAS COVERED IN THIS REVIEW

This review discusses the mechanisms and treatment for dyslipidaemia in the metabolic syndrome and type 2 diabetes.

WHAT THE READER WILL GAIN

A comprehensive understanding of the pathophysiology and pharmacotherapy of dyslipidaemia in the metabolic syndrome and diabetes.

TAKE HOME MESSAGE

Dysregulation of lipoprotein metabolism may be due to a combination of overproduction of triglyceride-rich lipoproteins, decreased catabolism of apoB-containing particles, and increased catabolism of HDL particles. These abnormalities may be consequent on a global metabolic effect of insulin resistance and an excess of both visceral and hepatic fat. Lifestyle modifications may favourably alter lipoprotein transport in the metabolic syndrome. Patients with dyslipidaemia and established cardiovascular disease should receive a statin as first-line therapy. Combination with other lipid-regulating agents, such as ezetimibe, fibrates, niacins and fish oils may optimize the benefit of statin on atherogenic dyslipidaemia.

Mechanisms for therapeutic correction of dyslipidaemia in insulin resistance and diabetes

Dyslipidaemia is a common cardiovascular risk factor in insulin resistant subjects with obesity, type 2 diabetes mellitus and the metabolic syndrome. Lipoprotein metabolism is complex and abnormal plasma concentrations result from alterations in the rates of production and/or catabolism of diverse lipoprotein particles. Understanding the dysregulation and therapeutic correction of lipoprotein transport in insulin resistant states has relied on the use of stable isotope tracers and modelling methods. The effects of lifestyle and therapeutic interventions on the kinetics of apolipoproteins B-100 and A-I containing lipoproteins are reviewed.

Regulatory effects of fenofibrate and atorvastatin on lipoprotein A-I and lipoprotein A-I:A-II kinetics in the metabolic syndrome

OBJECTIVE

Subjects with the metabolic syndrome have reduced HDL cholesterol concentration and altered metabolism of high-density lipoprotein (Lp)A-I and LpA-I:A-II particles. In the metabolic syndrome, fenofibrate and atorvastatin may have differential effects on HDL particle kinetics.

RESEARCH DESIGN AND METHODS

Eleven men with metabolic syndrome were studied in a randomized, double-blind, crossover trial of 5-week intervention periods with placebo, fenofibrate (200 mg/day), and atorvastatin (40 mg/day). LpA-I and LpA-I:A-II kinetics were examined using stable isotopic techniques and compartmental modeling.

RESULTS

Compared with placebo, fenofibrate significantly increased the production of both LpA-I:A-II (30% increase; P < 0.001) and apoA-II (43% increase; P < 0.001), accounting for significant increases of their corresponding plasma concentrations (10 and 23% increases, respectively), but it did not alter LpA-I kinetics or concentration. Atorvastatin did not significantly alter HDL concentration or the kinetics of HDL particles.

CONCLUSIONS

In the metabolic syndrome, fenofibrate, but not atorvastatin, influences HDL metabolism by increasing the transport of LpA-I:A-II particles.

Catabolism of lipoproteins and metabolic syndrome

PURPOSE OF REVIEW

Metabolic syndrome is very common and is associated with significantly increased risk for both cardiovascular disease and type 2 diabetes. At present, no unifying mechanism can explain it. However, insulin resistance is a key feature of this syndrome, plays a key role in triglyceride metabolism and contributes to dyslipidemia and development of type 2 diabetes. Here, we review the mechanisms involved in the overproduction of large VLDL and their catabolism and finally potential therapeutic targets to provide a more complete approach to treatment of these lipid abnormalities.

RECENT FINDINGS

Dyslipidemia plays an important role in the development of atherosclerosis and is mainly associated by the hepatic overproduction of large triglyceride-rich VLDL, low levels of HDL cholesterol and high levels of small, dense, LDL cholesterol particles. It is thus of special interest to understand the mechanism involved in the hepatic synthesis of lipoproteins and the degradation of these lipoproteins that depend, to a large extent, on insulin action.

SUMMARY

The atherogenic lipid abnormalities observed in the metabolic syndrome may require a combination of drugs such as statins and HDL-raising agents to provide a more complete approach to treating dyslipidemia and reducing cardiovascular risk.

Efficacy and safety of rosuvastatin in the management of dyslipidemia

Rosuvastatin is a synthetic statin that represents an advance in the pharmacologic and clinical properties of statins. Relative to other statins, rosuvastatin possesses a greater number of binding interactions with HMG-CoA reductase and has a high affinity for the active site of the enzyme. As with other statins, serious adverse effects with rosuvastatin therapy are uncommon and primarily involve effects on the liver and skeletal muscle. The risk increases with increasing dosages and coadministration with other drugs interacting with the same metabolic pathway. The degree of LDL reduction is important to achieve the treatment goals suggested by international guidelines. Among the most potent statins, rosuvastatin is capable of getting the majority of patients to their LDL cholesterol goals. In addition, rosuvastatin has been found effective in reducing small-dense LDL, C-reactive protein and in increasing HDL cholesterol levels. Controlled clinical trials using vascular end-points have been performed. In particular, a study demonstrated that rosuvastatin therapy could slow progression and/or cause regression of carotid intima-media thickness over 2 years in middle-aged individuals with a low Framingham risk score (FRS) and mild to moderate subclinical atherosclerosis. A primary prevention study (JUPITER) was stopped before the programmed end of the study, because of excess benefit for high-risk individuals receiving rosuvastatin treatment. It is suggested that pronounced LDL reduction, in association with significant HDL cholesterol increase, are the bases of a marked preventive action of rosuvastatin. The results from JUPITER support the use of rosuvastatin for primary cardiovascular prevention, in overweight men and women, with near to normal LDL cholesterol and high CRP. There is now evidence of benefit from rosuvastatin treatment for a wide segment of the general population at intermediate cardiovascular risk. In absolute numbers, this segment represents the main source of cardiovascular events: on the basis of JUPITER results, it is expected that treatment target and potential candidates to statin therapy will be revaluated and redefined.

Dose-dependent effect of rosuvastatin treatment on HDL-subfraction phenotype in patients with primary hyperlipidemia

Although the raising effect of rosuvastatin on high-density lipoprotein cholesterol is well-established, there is a paucity of data regarding the effect of this statin on the high-density lipoprotein subfraction phenotype. A total of 150 participants without evidence of cardiovascular disease were randomized to therapeutic lifestyle modification (nonstatin-treated group) or to therapeutic lifestyle modification plus rosuvastatin at 10 mg/d (RSV10 group) or 20 mg/d (RSV20 group). We assessed the effect of rosuvastatin on the cholesterol mass of high-density lipoprotein subfractions at baseline as well as after 12 weeks post-treatment. Rosuvastatin treatment dose-dependently increased the high-density lipoprotein cholesterol (3.4% vs 5.3% in the RSV10 and RSV20 groups, respectively, P = .02). A dose-related rosuvastatin-induced increase in the cholesterol concentration of large high-density lipoprotein particles was also noted (by 11.4% in RSV10 group vs 22.0% in the RSV20 group, P = .01). Rosuvastatin treatment increases the high-density lipoprotein cholesterol by increasing the cholesterol mass only of the larger high-density lipoprotein particles in a dose-dependent manner.

Very low density lipoprotein metabolism and plasma adiponectin as predictors of high-density lipoprotein apolipoprotein A-I kinetics in obese and nonobese men

CONTEXT

Hypercatabolism of high-density lipoprotein (HDL) apolipoprotein (apo) A-I results in low plasma apoA-I concentration. The mechanisms regulating apoA-I catabolism may relate to alterations in very low density lipoprotein (VLDL) metabolism and plasma adiponectin and serum amyloid A protein (SAA) concentrations.

OBJECTIVE

We examined the associations between the fractional catabolic rate (FCR) of HDL-apoA-I and VLDL kinetics, plasma adiponectin, and SAA concentrations.

STUDY DESIGN

The kinetics of HDL-apoA-I and VLDL-apoB were measured in 50 obese and 37 nonobese men using stable isotopic techniques.

RESULTS

In the obese group, HDL-apoA-I FCR was positively correlated with insulin, homeostasis model of assessment for insulin resistance (HOMA-IR) score, triglycerides, VLDL-apoB, and VLDL-apoB production rate (PR). In the nonobese group, HDL-apoA-I FCR was positively correlated with triglycerides, apoC-III, VLDL-apoB, and VLDL-apoB PR and negatively correlated with plasma adiponectin. Plasma SAA was not associated with HDL-apoA-I FCR in either group. In multiple regression analyses, VLDL-apoB PR and HOMA-IR score, and VLDL-apoB PR and adiponectin were independently predictive of HDL-apoA-I FCR in the obese and nonobese groups, respectively. HDL-apoA-I FCR was positively and strongly associated with HDL-apoA-I PR in both groups.

CONCLUSIONS

Variation in VLDL-apoB production, and hence plasma triglyceride concentrations, exerts a major effect on the catabolism of HDL-apoA-I. Insulin resistance and adiponectin may also contribute to the variation in HDL-apoA-I catabolism in obese and nonobese subjects, respectively. We also hypothesize that apoA-I PR determines a steady-state, lowered plasma of apoA-I, which may reflect a compensatory response to a primary defect in the catabolism of HDL-apoA-I due to altered VLDL metabolism.

Rosuvastatin 20 mg restores normal HDL-apoA-I kinetics in type 2 diabetes

Catabolism of HDL particles is accelerated in type 2 diabetes, leading to a reduction in plasma residence time, which may be detrimental. Rosuvastatin is the most powerful statin to reduce LDL-cholesterol, but its effects on HDL metabolism in type 2 diabetes remain unknown. We performed a randomized double-blind cross-over trial of 6-week treatment period with placebo or rosuvastatin 20 mg in eight patients with type 2 diabetes. An in vivo kinetic study of HDL-apolipoprotein A-I (apoA-I) with (13)C leucine was performed at the end of each treatment period. Moreover, a similar kinetic study was carried out in eight nondiabetic normolipidemic controls. Rosuvastatin significantly reduced plasma LDL-cholesterol (-51%), triglycerides (TGs) (-38%), and HDL-TG (-23%). HDL-apoA-I fractional catabolic rate (FCR) was decreased by rosuvastatin (0.25 +/- 0.06 vs. 0.32 +/- 0.07 pool/day, P = 0.011), leading to an increase in plasma HDL-apoA-I residence time (4.21 +/- 1.02 vs. 3.30 +/- 0.73 day, P = 0.011). Treatment with rosuvastatin was associated with a concomitant reduction of HDL-apoA-I production rate. The decrease in HDL-apoA-I FCR, induced by rosuvastatin, was correlated with the reduction of plasma TGs and HDL-TG. HDL apoA-I FCR and production rate values in diabetic patients on rosuvastatin were not different from those found in controls. Rosuvastatin is responsible for a 22% reduction of HDL-apoA-I FCR and restores to normal the increased HDL turnover observed in type 2 diabetes. These kinetic modifications may have beneficial effects by increasing HDL plasma residence time.

Metabolic syndrome

Hirsutism is a finding that can lead to subsequent metabolic diagnoses such as the metabolic syndrome. Metabolic syndrome describes a cluster of cardiometabolic risk factors associated with overweight and obesity. Although it has been the subject of some controversy, perhaps due to the many definitions proposed by different health organizations, metabolic syndrome is clinically relevant in that it is a predictor of vascular risk, even independent of any associated type 2 diabetes. While various definitions may differ in precise cut-off points, they uniformly emphasize key pathophysiologic processes: visceral obesity, dyslipidemia, insulin resistance, and hypertension. Management of metabolic syndrome focuses on methods of reducing the component risk factors, and therapies thus target the above processes as well as controlling inflammation and the prothrombotic state. Treatments can include not only pharmacologic approaches but behavior modification as well.

Dose-dependent effect of rosuvastatin on VLDL-apolipoprotein C-III kinetics in the metabolic syndrome

OBJECTIVE

Dysregulated apolipoprotein (apo)C-III metabolism may account for hypertriglyceridemia and increased cardiovascular risk in the metabolic syndrome. This study investigated the dose-dependent effect of rosuvastatin on VLDL apoC-III transport in men with the metabolic syndrome.

RESEARCH DESIGN AND METHODS

Twelve men with the metabolic syndrome were studied in a randomized double-blind crossover trial of 5-week intervention periods with placebo, 10 mg rosuvastatin, or 40 mg rosuvastatin, with 2-week placebo washouts between each period. VLDL apoC-III kinetics were examined using a stable isotope method and compartmental modeling at the end of each intervention period.

RESULTS

Compared with placebo, there was a significant dose-dependent reduction with rosuvastatin in plasma triglyceride and VLDL apoC-III concentrations. Rosuvastatin significantly (P < 0.05) increased VLDL apoC-III fractional catabolic rate (FCR) and decreased its production rate, with a significant (P < 0.05) dose-related effect. With 40 mg rosuvastatin, changes in VLDL apoC-III concentration were inversely associated with changes in VLDL apoC-III FCR and positively associated with VLDL apoC-III production rate (P < 0.05). Changes in VLDL apoC-III concentration and production rate were positively correlated with changes in VLDL apoB concentration and production rate and inversely correlated with VLDL apoB FCR (P < 0.05). Similar associations were observed with 10 mg rosuvastatin but were either less or not statistically significant.

CONCLUSIONS

In this study, rosuvastatin decreased the production and increased the catabolism of VLDL apoC-III, a mechanism that accounted for the significant reduction in VLDL apoC-III and triglyceride concentrations. This has implications for the management of cardiometabolic risk in obese subjects with the metabolic syndrome.

HDL metabolism in context: looking on the bright side

PURPOSE OF REVIEW

To review new data concerning HDL metabolism and cardiovascular disease, the concept of HDL 'functionality', and HDL kinetics in the metabolic syndrome.

RECENT FINDINGS

HDL-apoA-I and apoA-II may be better predictors of cardiovascular disease than HDL-cholesterol. Cholesteryl ester transfer protein inhibition with torcetrapib does not benefit cardiovascular disease; whether this is related to 'congestion' of HDL transport or a specific off-target vasopressor effect remains unclear. Accelerated catabolism of HDL particles in metabolic syndrome could be due to increased hepatic secretion of apoB and apoC-III, hepatic steatosis, and low plasma adiponectin. The role of serum amyloid A and homocysteine is uncertain. In metabolic syndrome, therapies that could favourably alter HDL transport include weight loss, fish oils, higher dose statins, and fibrates; 'balancing feedback' may offset reduced catabolism of HDL, fenofibrate being the only agent hitherto shown to increase apoA-I production.

SUMMARY

Elevating HDL-apoA-I and apoA-II may be a more important therapeutic objective than increased HDL-cholesterol. Recent studies underscore the potential value of studying HDL functionality, particularly in the metabolic syndrome. Reverse cholesterol transport can only be reliably probed at present by studying the kinetics of HDL particles or apolipoproteins; new methods are needed for investigating cellular and whole body cholesterol turnover. In metabolic syndrome, HDL-raising therapies have differential impact on HDL kinetics, the optimal endpoint being to increase transport and concentration with unchanged or accelerated catabolism.