Comparison of gemfibrozil versus simvastatin in familial combined hyperlipidemia and effects on apolipoprotein-B-containing lipoproteins, low-density lipoprotein subfraction profile, and low-density lipoprotein oxidizability

Effect of PCSK9 inhibition with evolocumab on lipoprotein subfractions in familial dysbetalipoproteinemia (type III hyperlipidemia)

BACKGROUND AND AIMS

Familial dysbetalipoproteinemia (FDBL) is a rare inborn lipid disorder characterized by the formation of abnormal triglyceride- and cholesterol-rich lipoproteins (remnant particles). Patients with FDBL have a high risk for atherosclerotic disease. The effect of PCSK9 inhibition on lipoproteins and its subfractions has not been evaluated in FDBL.

METHODS

Three patients (65±7 years, 23±3 kg/m2, 2 females) with FDBL (diagnosed by isoelectrofocusing) and atherosclerosis (coronary and/or cerebro-vascular and/or peripheral arterial disease) resistant or intolerant to statin and fibrate therapy received evolocumab (140mg every 14 days). In addition to a fasting lipid profile (preparative ultracentrifugation), apoB and cholesterol concentrations were determined in 15 lipoprotein-subfractions (density gradient ultracentrifugation; d 1.006-1.21g/ml) before and after 12 weeks of evolocumab treatment. Patients with LDL-hypercholesterolemia (n = 8, 56±8 years, 31±7 kg/m2) and mixed hyperlipidemia (n = 5, 68±12 years, 30±1 kg/m2) also receiving evolocumab for 12 weeks were used for comparison.

RESULTS

All patients tolerated PCSK9 inhibition well. PCSK9 inhibitors reduced cholesterol (29-37%), non-HDL-cholesterol (36-50%) and apoB (40-52%) in all patient groups including FDBL. In FDBL, PCSK9 inhibition reduced VLDL-cholesterol and the concentration of apoB containing lipoproteins throughout the whole density spectrum (VLDL, IDL, remnants, LDL). Lipoprotein(a) was decreased in all patient groups to a similar extent.

CONCLUSIONS

This indicates that the dominant fraction of apoB-containing lipoproteins is reduced with PCSK9 inhibition, i.e. LDL in hypercholesterolemia and mixed hyperlipidemia, and cholesterol-rich VLDL, remnants and LDL in FDBL. PCSK9 inhibition may be a treatment option in patients with FDBL resistant or intolerant to statin and/or fibrate therapy.

Low density lipoprotein delays clearance of triglyceride-rich lipoprotein by human subcutaneous adipose tissue

Delayed clearance of triglyceride-rich lipoprotein (TRL) by white adipose tissue (WAT) promotes hypertriglyceridemia and elevated apoB-lipoproteins, which are primarily in the form of LDL. This study examines whether LDL promotes delayed clearance of TRL by WAT. Following the ingestion of a (13)C-triolein-labeled high-fat meal, obese women with high plasma apoB (> median 0.93 g/l, N = 11, > 98% as IDL/LDL) had delayed clearance of postprandial (13)C-triglyceride and (13)C-NEFA over 6 h compared with controls. AUC6 h of plasma (13)C-triglyceride and (13)C-NEFA correlated with plasma apoB but not with LDL diameter or adipocyte area. There was no group difference in (13)C-triolein oxidation rate, which suggests lower (13)C-NEFA storage in peripheral tissue in women with high apoB. Ex vivo/in vitro plasma apoB correlated negatively with WAT (3)H-lipid following a 4 h incubation of women's WAT with synthetic (3)H-triolein-TRL. LDL-differentiated 3T3-L1 adipocytes had lower (3)H-TRL hydrolysis and (3)H-NEFA storage. Treatment of women's WAT with their own LDL decreased (3)H-TRL hydrolysis and (3)H-NEFA uptake. Finally, LDL, although not an LPL substrate, reduced LPL-mediated (3)H-TRL hydrolysis as did VLDL and HDL. Exposure to LDL decreases TRL clearance by human WAT ex vivo. This may promote production of apoB-lipoproteins and hypertriglyceridemia through a positive-feedback mechanism in vivo.

Hypertriglyceridemia and hypercholesterolemia: effects of drug treatment on fatty acid composition of plasma lipids and membranes

The effect of atorvastatin, simvastatin and gemfibrozil on fatty acid composition of plasma phospholipids (PL), cholesterol esters (CE), triglycerides (TG) and red cell membrane ghosts (G) has been determined in appropriate sample populations of individuals with hypertriglyceridemia (HTG) or hypercholesterolemia (HCHL). Treatments were appropriate for the condition, gemfibrozil for HTG and a statin for HCHL. Modifications depend on the drug and lipid fraction examined. Both classes of drugs modify fatty acid composition but gemfibrozil modifications are more numerous and dramatic than are the modifications by statins. Gemfibrozil produces major modifications in fatty acid composition, which are both fatty acid and lipid class specific but generally decreases SFA and increases PUFA (mainly n6) and increases the proportion of fatty acids with chain length of 18C or more. Statins tend to increase chain length but have less effect on saturation. Notably, all three drugs increased arachidonic acid (AA) in PL and CE. Statins decreased gamma-linoleic acid (GLA) in PL and CE but gemfibrozil only increased GLA in TG.

Differential effect of atorvastatin and fenofibrate on plasma oxidized low-density lipoprotein, inflammation markers, and cell adhesion molecules in patients with type 2 diabetes mellitus

Type 2 diabetes mellitus is associated with elevated plasma triglyceride levels, low high-density lipoprotein cholesterol, and a high incidence of cardiovascular disease. Hydroxymethylglutaryl-coenzyme A reductase inhibitors and fibrates are frequently used in the treatment of diabetic dyslipidemia, but their specific impact on the inflammation processes involved in atherosclerosis remains to be fully characterized. The objective of this 2-group parallel study was to investigate the differential effects of a 6-week treatment with either atorvastatin 20 mg/d alone (n = 19) or micronized fenofibrate 200 mg/d alone (n = 19) on inflammation, cell adhesion, and oxidation markers in type 2 diabetes mellitus subjects with marked hypertriglyceridemia. In addition to the expected changes in lipid levels, atorvastatin decreased plasma levels of C-reactive protein (-26.9%, P = .004), soluble intercellular adhesion molecule 1 (-5.4%, P = .03), soluble vascular cell adhesion molecule 1 (-4.4%, P = .008), sE-selectin (-5.7%, P = .02), matrix metalloproteinase 9 (-39.6%, P = .04), secretory phospholipase A(2) (sPLA(2)) (-14.8%, P = .04), and oxidized low-density lipoprotein (-38.4%, P < .0001). On the other hand, fenofibrate had no significant effect on C-reactive protein levels and was associated with reduced plasma levels of sE-selectin only (-6.0%, P = .04) and increased plasma levels of sPLA(2) (+22.5%, P = .004). These results suggest that atorvastatin was potent to reduce inflammation, oxidation, and monocyte adhesion in type 2 diabetes mellitus subjects with marked hypertriglyceridemia, whereas fenofibrate decreased sE-selectin levels only and was associated with an elevation of sPLA(2) levels.

The clinical significance of the size of low-density-lipoproteins and the modulation of subclasses by fibrates

BACKGROUND

Beyond total low-density-lipoproteins (LDL) levels, increasing evidence suggests that the 'quality' of LDL exerts a great influence on the cardiovascular risk. Several studies have also shown that the therapeutic modulation of LDL size is of benefit in reducing the risk of cardiovascular events. Hypolipidaemic treatment is able to alter LDL subclass distribution but strong variations have been noticed among different agents. Fibrates have a major impact on triglyceride metabolism and in modulating LDL size and subclasses, but variations exist among the different molecules.

METHODOLOGY

A literature search (by Medline and Scopus) was performed using the following headings: 'small dense LDL', 'LDL size', 'LDL subfractions', 'LDL subclasses', 'LDL distribution' and 'fenofibrate', 'bezafibrate', 'ciprofibrate' and 'gemfibrozil' up to 20 January 2007. The authors also manually reviewed the references of selected articles for any pertinent material.

RESULTS

Analysis of all published studies revealed that treatment with fenofibrate, ciprofibrate, bezafibrate and gemfibrozil is usually beneficial, and fenofibrate may be more efficacious than the other molecules. This is supported by using all the available techniques in subjects with a very wide range of lipid alterations.

CONCLUSION

Among the different agents, fenofibrate has been found to be particularly effective in modulating LDL size and subclasses in patients at higher cardiovascular risk, such as those with type 2 diabetes or the metabolic syndrome.

Clinical importance and therapeutic modulation of small dense low-density lipoprotein particles

The National Cholesterol Education Programme Adult Treatment Panel III accepted the predominance of small dense low-density lipoprotein (sdLDL) as an emerging cardiovascular disease (CVD) risk factor. Most studies suggest that measuring low-density lipoprotein (LDL) particle size, sdLDL cholesterol content and LDL particle number provides additional assessment of CVD risk. Therapeutic modulation of small LDL size, number and distribution may decrease CVD risk; however, no definitive causal relationship is established, probably due to the close association between sdLDL and triglycerides and other risk factors (e.g., high-density lipoprotein, insulin resistance and diabetes). This review addresses the formation and measurement of sdLDL, as well as the relationship between sdLDL particles and CVD. The effect of hypolipidaemic (statins, fibrates and ezetimibe) and hypoglycaemic (glitazones) agents on LDL size and distribution is also discussed.

Beneficial effect of simvastatin treatment on LDL oxidation and antioxidant protection is more pronounced in combined hyperlipidemia than in hypercholesterolemia

AIMS

Beneficial effects of statin treatment on cardiovascular morbidity and mortality has been not entirely explained by the reduction in LDL-cholesterol level. We hypothesised that antioxidant activity of statins may contribute to their salutary cardiovascular effects. The aim of the present study was to examine effect of simvastatin treatment on some parameters of LDL oxidation and antioxidant protection in patients with hypercholesterolemia and combined hyperlipidemia. Furthermore, we were interested, whether the effect of treatment is related to the type of hyperlipidemia.

PATIENTS AND METHODS

Fourty-two patients (12 males, 30 females, mean age 60+/-10 years) were included in the present study. Fourteen patients had hypercholesterolemia defined as total cholesterol>5.0 mmol/l. Twenty-eight patients had combined hyperlipidemia defined by total cholesterol>5.0 mmol/l and triglycerides>1.7 mmol/l. Simvastatin was administered to patients during 8-week period in a daily dose of 20mg. Oxidation of LDL was measured by assessment of circulating conjugated diene (CD) and malondialdehyde (MDA) level. Antioxidant properties of blood were assessed based on measurement of total antioxidant status (TAS) and glutathione peroxidase (GPx) activity.

RESULTS

Besides expected significant decrease in total cholesterol, LDL-cholesterol, apolipoprotein B and triglyceride levels, simvastatin treatment also reduced significantly circulating CD by 41% (p<0.0001) and MDA level non-significantly by 6% (p=0.078). Simvastatin treatment resulted in an increase of GPx activity by 38% (p<0.0001), but did not have a significant effect on TAS. Patients with combined hyperlipidemia had significantly higher baseline CD (p<0.01) and consequently significantly greater absolute and relative decrease (46% versus 23%) in circulating CD (DeltaCD), when compared with patients with hypercholesterolemia. The increase in GPx activity was significant only in patients with combined hyperlipidemia (p<0.0001). In the multiple stepwise linear regression analysis, both baseline triglyceride (r(2)=0.32; p=0.004) and LDL cholesterol (r(2)=0.08; p=0.05) levels were significant independent predictors of DeltaCD after simvastatin treatment.

CONCLUSION

Simvastatin treatment significantly reduced circulating conjugated diene level and led to an increase in glutathione peroxidase activity. These effects were more pronounced in patients with combined hyperlipidemia than in hypercholesterolemia. The results suggest that simvastatin possesses certain antioxidant properties, which may contribute to its beneficial cardiovascular effect.

The Clinical Relevance of Low-Density-Lipoproteins Size Modulation by Statins

The predominance of small, dense low density lipoproteins (LDL) has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III; in fact, LDL size seems to be an important predictor of cardiovascular events and progression of coronary heart disease. Several studies have also shown that the therapeutical modulation of LDL size is of great benefit in reducing the risk of cardiovascular events. Hypolipidemic treatment is able to alter LDL subclass distribution and statins are currently the most widely used lipid-lowering agents. Statins are potent inhibitors of hydroxy-methyl-glutaryl-coenzyme A reductase, the rate-limiting enzyme in hepatic cholesterol synthesis and are the main drugs of choice for the treatment of elevated plasma LDL cholesterol concentrations. Statins potentially lower all LDL subclasses (e.g., large, medium and small particles); thus, their net effect on LDL subclasses or size is often only moderate. However, a strong variation has been noticed among the different agents: analyses of all published studies suggest a very limited role of pravastatin and simvastatin in modifying LDL size and their subclasses, while fluvastatin and atorvastatin seem to be much more effective agents. Finally, rosuvastatin, the latest statin molecule introduced in the market, seems to be promising in altering LDL subclasses towards less atherogenic particles.

Low-density lipoprotein size and cardiovascular risk assessment

A predominance of small, dense low-density lipoproteins (LDL) has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III. LDL size seems to be an important predictor of cardiovascular events and progression of coronary heart disease and evidences suggests that both quality (particularly small, dense LDL) and quantity may increase cardiovascular risk. However, other authors have suggested that LDL size measurement does not add information beyond that obtained by measuring LDL concentration, triglyceride levels and HDL concentrations. Therefore, it remains debatable whether to measure LDL particle size in cardiovascular risk assessment and, if so, in which categories of patient. Therapeutic modulation of LDL particle size or number appears beneficial in reducing the risk of cardiovascular events, but no clear causal relationship has been shown, because of confounding factors, including lipid and non-lipid variables. Studies are needed to investigate the clinical significance of LDL size measurements in patients with coronary and non-coronary forms of atherosclerosis; in particular, to test whether LDL size is associated with even higher vascular risk, and whether LDL size modification may contribute to secondary prevention in such patients.

Effects of Atorvastatin on Low-Density Lipoprotein Cholesterol Phenotype and C-Reactive Protein Levels in Patients Undergoing Long-Term Dialysis

STUDY OBJECTIVES

To determine the effects of atorvastatin on low-density lipoprotein cholesterol (LDL) particle size and C-reactive protein (CRP) concentrations in patients undergoing long-term hemodialysis. Another objective was to compare the effects of atorvastatin on lipoprotein profiles as determined by direct versus indirect assessment of lipoprotein composition.

DESIGN

Randomized, parallel-group substudy.

SETTING

Two university-affiliated outpatient hemodialysis centers.

PATIENTS

Nineteen patients with LDL levels above 100 mg/dl and with at least two cardiovascular risk factors.

INTERVENTION

Patients were randomized in a 1:1 ratio to atorvastatin 10 mg/day or no treatment (control) for 20 weeks.

MEASUREMENTS AND MAIN RESULTS

We compared the differences between LDL particle size and CRP levels at baseline and 20 weeks in the atorvastatin versus control groups. Baseline demographic characteristics were similar between the two groups. Atorvastatin therapy was associated with no change in mean LDL particle size (p=0.23) and with a 90% decrease in mean CRP level (p=0.52). When evaluated by standard chemical analysis, atorvastatin therapy reduced total cholesterol levels by 29% (p=0.025) and resulted in nonsignificant reductions in LDL, high-density lipoprotein cholesterol, and triglyceride levels. Treatment with atorvastatin was not associated with significant changes in lipoprotein profile as determined by nuclear magnetic resonance (NMR) spectroscopy.

CONCLUSION

Treatment with atorvastatin did not affect LDL particle size but was associated with a sizable, yet nonsignificant, reduction in CRP concentrations. The drug had variable effects on lipoprotein concentrations as determined by chemical and NMR analytical methods. A larger study is necessary to provide definitive information on the effects of atorvastatin on LDL phenotype and CRP in patients with kidney disease.

Effects of atorvastatin on the clearance of triglyceride-rich lipoproteins in familial combined hyperlipidemia

Familial combined hyperlipidemia (FCHL) patients have an impaired catabolism of postprandial triglyceride (TG)-rich lipoproteins (TRLs). We investigated whether atorvastatin corrects the delayed clearance of large TRLs in FCHL by evaluating the acute clearance of Intralipid (10%) and TRLs after oral fat-loading tests. Sixteen matched controls were included. Atorvastatin reduced fasting plasma TG (from 3.6 +/- 0.4 to 2.5 +/- 0.3 mM; mean +/- SEM) without major effects on fasting apolipoprotein B48 (apoB48) and apoB100 in large TRLs. Atorvastatin significantly reduced fasting intermediate density lipoprotein (Svedberg flotation, 12-20)-apoB100 concentrations. After Intralipid, TG in plasma and TRL showed similar kinetics in FCHL before and after atorvastatin treatment, although compared with controls, the clearance of large TRLs was only significantly slower in untreated FCHL, suggesting an improvement by atorvastatin. Investigated with oral fat-loading tests, the clearance of very low density lipoprotein (Sf20-60)-apoB100 improved by 24%, without major changes in the other fractions. The most striking effects of atorvastatin on postprandial lipemia in FCHL were on hepatic TRL, without major improvements on intestinal TRLs. Fasting plasma TG should be reduced more aggressively in FCHL to overcome the lipolytic disturbance causing delayed clearance of postprandial TRLs.

An omega-3 polyunsaturated fatty acid concentrate increases plasma high-density lipoprotein 2 cholesterol and paraoxonase levels in patients with familial combined hyperlipidemia

A remarkable reduction of plasma concentrations of high-density lipoproteins (HDL), especially of the HDL(2) subfraction, is one of the typical lipoprotein alterations found in patients with familial combined hyperlipidemia (FCHL). Fourteen FCHL patients received 4 capsules daily of Omacor (an omega-3 polyunsaturated fatty acid [omega3 FA] concentrate providing 1.88 g of eicosapentaenoic acid [EPA] and 1.48 g of docosahexaenoic acid [DHA] per day; Pronova Biocare, Oslo, Norway) or placebo for 8 weeks in a randomized, double-blind, crossover study. Plasma triglycerides were 44% lower, and LDL cholesterol and apoliporpotein (apo)B were 25% and 7% higher after Omacor than placebo. HDL cholesterol was higher (+8%) after Omacor than placebo, but this difference did not achieve statistical significance. Omacor caused a selective increase of the more buoyant HDL(2) subfraction; plasma HDL(2) cholesterol and total mass increased by 40% and 26%, respectively, whereas HDL(3) cholesterol and total mass decreased by 4% and 6%. Both HDL(2) and HDL(3) were enriched in cholesteryl esters and depleted of triglycerides after Omacor. No changes were observed in the plasma concentration of major HDL apolipoproteins, LpA-I and LpA-I:A-II particles, lecithin:cholesterol acyltransferase (LCAT), and cholesteryl ester transfer protein (CETP). The plasma concentration of the HDL-bound antioxidant enzyme paraoxonase increased by 10% after Omacor. Omacor may be helpful in correcting multiple lipoprotein abnormalities and reducing cardiovascular risk in FCHL patients.

[Non-lipid effects of statins: myth or fact?]

Hydroxy-methylglutaryl coenzyme A reductase-inhibitors (HMG-CoA [statins]) are currently the most effective method to pharmacologically decrease total plasma cholesterol levels. A number of multicenter studies have demonstrated, that statins administered for several years lead to a significant reduction of cardiovascular events and mortality compared with placebo. Apart from the well known LDL- and cholesterol lowering effect, statins have been postulated to exert beneficial effects on mortality due to so called 'non-lipid effects'. There is circumstantial evidence from a number of experimental studies that statins can improve endothelial function, exert anti-inflammatory and anti-oxidative effects, stabilize arteriosclerotic plaque and inhibit proliferation and activation of smooth muscle cells. However, the clinical implications of these beneficial 'non-lipid effects' are unclear, but appear to exert only a minor role in comparison to the lowering effect of statins on total plasma cholesterol levels.

Beneficial effects of fish liver preparations of sea bass (Lates calcarifer) versus gemfibrozil in high fat diet-induced lipid-intolerant rats

Abnormal lipid metabolism is a main cause of dyslipidemia, which is a major risk factor for coronary heart disease and obesity and is even linked to diabetic-dyslipidemic complications. Fifteen days of high-fat feeding in Charles Foster rats resulted in a significant increase in baseline serum lipid levels accompanied by pronounced dyslipidemia. Treatment with fish liver preparations (FLPs) from sea bass and the standard drug gemfibrozil produced a lowering of serum lipids and glucose levels, along with a fall in very-low-density and low-density lipoprotein and an increase in high-density lipoprotein levels. Simultaneously, reactivation of plasma postheparin lipolytic activity (PHLA) and lecithin:cholesterol acyltransferase (LCAT) activity was also observed. A positive correlation was observed between low-density lipoprotein activity and fecal bile acid excretion, which was enhanced on treatment with FLPs and gemfibrozil, indicating the catabolic process for normal lipids and cholesterol homeostasis. These data suggest that FLPs and gemfibrozil not only lower lipid intolerance but also reduce diabetic-dyslipidemic complications by activating peroxisome proliferator-activated receptors (PPAR).

Effect of 12-month statin therapy on antioxidant potential of LDL and serum antioxidant vitamin concentrations

BACKGROUND

Statins are known to cause short-term reduction in serum lipid-soluble antioxidant concentrations, but their long-term effects are not known.

AIM

We randomised 104 subjects with CHD and hypercholesterolaemia to receive either atorvastatin or simvastatin treatment for 52 weeks and measured the antioxidant potential of LDL and serum antioxidant vitamin concentrations.

METHOD

Initial daily dose for both statins was 20 mg.

RESULTS

LDL antioxidant capacity and serum alpha-tocopherol, gamma-tocopherol and beta-carotene concentrations decreased by 22%-35% with both statins during the first 12 weeks' therapy (P < 0.01 for all). After 52 weeks' therapy, the concentrations of serum gamma-tocopherol in the simvastatin group and serum beta-carotene in both treatment groups returned to baseline levels, while the concentrations of serum gamma-tocopherol in the atorvastatin group and LDL anti-oxidant capacity and serum alpha-tocopherol in both treatment groups remained reduced (P < 0.001 for all). The LDL antioxidant capacity:LDL-cholesterol and the serum alpha-tocopherol:LDL-cholesterol ratios were significantly elevated with both statins after 12 and 52 weeks (P < 0.001 for all). Statistically significant increases were also observed for corresponding ratios of the less abundant vitamins gamma-tocopherol and beta-carotene.

CONCLUSIONS

Some of the decreases in serum lipid soluble antioxidant vitamins reported in short-term statin interventions may become attenuated when therapy continues longer. The relative antioxidant capacity of LDL particles increased during the 52-week treatment, suggesting that the oxidation resistance of LDL particles did not become impaired and that their atherogenicity did not increase.

Effect of atorvastatin on the concentration, relative distribution, and chemical composition of lipoprotein subfractions in patients with dyslipidemias of type IIA and IIB

The authors investigated the effect of atorvastatin (40 mg qd) on low-density lipoprotein (LDL) particle distribution in patients with dyslipidemias of type IIA (n = 55) and IIB (n = 21). Atorvastatin therapy induced a significant decrease in total and LDL cholesterol in both patient groups. A significant reduction in triglyceride values, which was more profound in type IIB patients, was also observed. In type IIA patients, LDL-3 was the predominant subfraction. Atorvastatin therapy induced a significant reduction in total LDL mass in this group of patients that was mainly due to the reduction in large and intermediate subspecies (LDL-1 to LDL-3), whereas the mass of dense LDL particles (LDL-4 and LDL-5) remained unchanged. As a consequence, the percentage contribution of dense subfractions to the total LDL mass increased significantly after atorvastatin therapy. The dense LDL-4 subfraction was the predominant one in type IIB patients. In this group, atorvastatin therapy resulted in a significant reduction in the total LDL mass, which was due to the reduction in all LDL subfractions. Thus, the percentage mass distribution of LDL particles remained unaffected. These results suggest that the effect of atorvastatin on LDL subfractions is affected by the underlying genetic defect.

Improvement of serum oxidation by pravastatin might be one of the mechanisms by which endothelial function in dilated coronary artery segments is ameliorated

BACKGROUND

Oxidation susceptibility of lipids in vitro is considered to reflect the exposure of lipids to oxidation stress in vivo which is related to cardiovascular morbidity. This study examined the effect of pravastatin therapy on serum oxidation susceptibility, particularly in relation to endothelial function of coronary arteries.

METHODS

The participants were recruited from the Pravastatin-Related Effects Following Angioplasty on Coronary Endothelium trial, a double-blinded, placebo-controlled, randomized, multi-center study designed to analyze the effect of pravastatin treatment on endothelial function in previously dilated and normal coronary arteries. Serial, graded, intra-coronary acetylcholine infusions were used to assess endothelial function. In vitro, copper-induced, serum oxidation parameters were determined at randomization and at time of coronary endothelial function assessment.

RESULTS

Oxidation parameters were determined in 45 patients (pravastatin 23, placebo 22). Pravastatin therapy significantly improved serum oxidation lag time (+8%, P<0.05), maximal diene formation rate (-22%, P<0.01) and total amount of dienes formed after 5 h (-16%, P<0.01). These parameters remained essentially unchanged in the placebo group. Acetylcholine-evoked responses were positively correlated to therapy-induced change in serum oxidation susceptibility in the dilated segment group (r2=0.56, P=0.006).

CONCLUSION

Pravastatin's beneficial effect on endothelial dysfunction of dilated coronary segments may be secondary to pravastatin's improvement of oxidation susceptibility.

Effects of simvastatin and pravastatin on peroxidation of erythrocyte plasma membrane lipids in patients with type 2 hypercholesterolemia

Since hypercholesterolemia directly modifies the composition of erythrocytes plasma membrane, the influence of statins on erythrocytes has been researched. The beneficial effects of statins on clinical events may involve mechanisms that modify endothelial dysfunction, plaque stability, thrombus formation and inflammatory responses. The aim of the study was to evaluate the hypolipemic efficacy and effects of pravastatin and simvastatin on erythrocyte membrane fluidity and damage of erythrocytes in patients with type 2 hypercholesterolemia in comparison with a control group of healthy subjects. The study involved 53 patients affected by type 2 hypercholesterolemia (mean age, 53.3 +/- 10.3) with initial total serum cholesterol (TC) levels > 250 mg/dL, LDL-cholesterol (LDL-C) levels > 170 mg/dL, and triglycerides (TG) levels < 400 mg/dL. The control group consisted of 30 healthy individuals (mean age 56.9 +/- 6.3). Statins were given for 12 weeks. The dosages for oral administration of simvastatin and pravastatin were 20 mg/day. Laboratory tests were carried out before and after 4 and 12 weeks of the pharmacological treatment. The damage to plasma membrane of erythrocytes was measured on the basis of lipid peroxidation. The fluidity of plasma membrane of erythrocytes was determined by electron paramagnetic resonance (EPR) spectroscopy, using two spin labels: 5-DSA and 16-DSA. The cholesterol level in the membrane of red blood cells was estimated. Simvastatin and pravastatin reduced the total cholesterol concentration and LDL-cholesterol in plasma, as well as the cholesterol concentration in erythrocytes membranes. Hypercholesterolemia induced changes in the basic properties of human erythrocyte plasma membrane, including its fluidity and the intensity of lipid peroxidation. These results indicate that the simvastatin and pravastatin therapy reverses the alteration in the erythrocyte plasma membrane properties.

Atorvastatin versus Bezafibrate in Mixed Hyperlipidaemia : Randomised Clinical Trial of Efficacy and Safety (the ATOMIX Study)

OBJECTIVE

Combined hyperlipidaemia is a common and highly atherogenic lipid phenotype with multiple lipoprotein abnormalities that are difficult to normalise with single-drug therapy. The ATOMIX multicentre, controlled clinical trial compared the efficacy and safety of atorvastatin and bezafibrate in patients with diet-resistant combined hyperlipidaemia.

PATIENTS AND STUDY DESIGN

Following a 6-week placebo run-in period, 138 patients received atorvastatin 10mg or bezafibrate 400mg once daily in a randomised, double-blind, placebo-controlled trial. To meet predefined low-density lipoprotein-cholesterol (LDL-C) target levels, atorvastatin dosages were increased to 20mg or 40mg once daily after 8 and 16 weeks, respectively.

RESULTS

After 52 weeks, atorvastatin achieved greater reductions in LDL-C than bezafibrate (percentage decrease 35 vs 5; p < 0.0001), while bezafibrate achieved greater reductions in triglyceride than atorvastatin (percentage decrease 33 vs 21; p < 0.05) and greater increases in high-density lipoprotein-cholesterol (HDL-C) [percentage increase 28 vs 17; p < 0.01 ]. Target LDL-C levels (according to global risk) were attained in 62% of atorvastatin recipients and 6% of bezafibrate recipients, and triglyceride levels <200 mg/dL were achieved in 52% and 60% of patients, respectively. In patients with normal baseline HDL-C, bezafibrate was superior to atorvastatin for raising HDL-C, while in those with baseline HDL-C <35 mg/dL, the two drugs raised HDL-C to a similar extent after adjustment for baseline values. Both drugs were well tolerated.

CONCLUSION

The results show that atorvastatin has an overall better efficacy than bezafibrate in concomitantly reaching LDL-C and triglyceride target levels in combined hyperlipidaemia, thus supporting its use as monotherapy in patients with this lipid phenotype.

N-3 fatty acids and diabetes

Fatty acids of the omega-3 series (n-3 fatty acids) are a well established dietary component affecting plasma lipids (mainly triglycerides) and also major cardiovascular parameters, such as arrhythmogenesis. In view of their peculiar metabolic handling, it has been suggested that they may reduce glucose tolerance in patients predisposed to diabetes. On the other hand, insulin is required for the endogenous synthesis of the long chain n-3 fatty acids from precursors; the heart may thus be particularly susceptible to their depletion in diabetes. This review examines large population studies, carried out particularly by this research group, evaluating the risk of developing glucose intolerance/clearcut diabetes in large series of patients with predisposing conditions. While diabetes development was in no way accelerated in any of these studies, there was, instead, clear evidence of a significant hypotriglyceridemic activity of the supplements. In long-term treatments, there was also a tendency toward a significant reduction of low density lipoprotein (LDL) cholesterolemia, with positive effects on high density lipoprotein (HDL). These findings fit well with cellular changes indicative of improved glucose handling. Finally, recent data suggest an improvement of heart rate variability by fish intake in coronary patients, that is also exerted by the n-3 fatty acids given as ethyl esters, thus providing further indication for the potential benefit of such treatments in diabetic patients.

Gemfibrozil lowers plasma lipids and increases polyunsaturated fatty acid content and oxidative susceptibility of lipoproteins in hypertriglyceridemia

BACKGROUND

Gemfibrozil is an effective drug in the treatment of hypertriglyceridemia and its effects on morbidity and mortality seem out of proportion to its lipid lowering actions. There is considerable interest in its potential effects on lipoprotein fatty acid composition and consequent effect on oxidative susceptibility. Experimental results are not conclusive regarding whether gemfibrozil alters lipid composition or oxidative susceptibility of lipoproteins in humans. Here we investigate this question using different methodology than employed in previous investigations.

METHODS

Eleven hypertriglyceridemic individuals completed a 12-week course of gemfibrozil therapy (600 mg twice daily) intended to primarily evaluate a new way of assessing lipoprotein susceptibility to oxidation in relation to changes in the fatty acid profile. We measured susceptibility of lipoproteins in the plasma macromolecule fraction to copper-mediated oxidation. In addition, plasma lipids were separated into phospholipid (PL), cholesterol ester (CE) and triglyceride (TG) fractions and the fatty acid composition of these classes determined by gas-liquid chromatography. The relation between changes in lipid concentration, fatty acid composition and oxidative parameters (principally lag time) was examined by correlational analysis.

RESULTS

Triglyceride concentrations and total cholesterol concentrations responded appropriately to gemfibrozil (lowered by 55% and 15%, respectively). Polyunsaturated fatty acid (PUFA) proportion increased significantly in cholesterol ester and phospholipid fractions of plasma lipids at the expense of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA). Oxidative parameters also changed significantly. Lag time (LT) and maximal extent of oxidation showed the most significant changes. Lag time, the principle measure of lipoprotein susceptibility to oxidation, was decreased by gemfibrozil. The increase in polyunsaturated fatty acid content in phospholipid and cholesterol ester significantly correlated with decreased lag time.

CONCLUSION

These data support the notion that gemfibrozil increases the proportion of polyunsaturated fatty acids in plasma lipids and that this increase is associated with an increase in lipoprotein oxidative susceptibility as measured by lag time in hypertriglyceridemia.

Treatment of hypertriglyceridemia with fenofibrate, fatty acid composition of plasma and LDL, and their relations to parameters of lipoperoxidation of LDL

The purpose of this study was to determine oxidation and oxidability of VLDL and LDL in connection with changes in their composition and content of FA in LDL after treatment with fenofibrate in patients with HTG.

Effects of a lipid lowering fibrate and hormone replacement therapy on serum lipids and lipoproteins in overweight postmenopausal women with elevated triglycerides

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death in women after menopause. In essence major risk factors for CVD are similar in women as for men inclusive of serum lipid perturbations. The effects of estrogens and hormone replacement therapy on lipid metabolism is widely discussed and warrant further evaluation especially when combined with other lipid lowering drugs.

STUDY DESIGN

Postmenopausal women were studied by an open randomised study during 9 months. Subjects were recruited from outpatient clinics in a rural area of Sweden. Major inclusive criteria comprised body mass index (BMI) >28, serum triglycerides >1.5 mmol/l. Participants were at least 12 months postmenopause with a concomitant serum Follicle Stimulating Hormone (FSH) above 28 IU/l. After inclusion in the study patients were instructed to adhere to a low-fat and caloric diet for 3 months and after this period randomised into two groups of intervention; a lipidlowering fibrate (LLF) group and one hormone replacement therapy group (HRT). The LLF group was given gemfibrozil 600 mg orally twice daily and HRT group received 2 mg oestradiol in combination with 1 mg norethisterone acetate as a continuous combined therapy once daily. After 3 months, the LLF group added the HRT regimen and patients in the HRT group added gemfibrozil. Hence, all participants received the regimens combined for the last 6 months of the study.

RESULTS

Serum s-cholesterol was markedly decreased in both groups during the first 3 months of single treatment (P<0.0001). This decrease reflected a reduction especially of calculated low density lipoprotein (LDL) s-cholesterol (P<0.001). High density lipoprotein (HDL) s-cholesterol was reduced in the HRT group (P<0.005) but increased (P<0.004) in the LLF group. Triglycerides were also decreased by both treatments but more marked in the LLF group (P<0.0001) than in the HRT group (P<0.02). After 9 months the reduction remained in both groups but no additive effects were encountered in any of the groups.

CONCLUSION

The effects by gemfibrozil on s-cholesterol and triglycerides levels seem to be superior to continuous combined HRT in overweight women with elevated triglycerides. The combination of the two drugs did not seem to offer any additional benefit concerning the routine serum lipid or lipoprotein profile.

Effects of pravastatin treatment on lipoprotein subclass profiles and particle size in the PLAC-I trial

Lipoprotein subclass analyses may facilitate coronary heart disease (CHD) risk stratification and provide insight into the cardioprotective benefits of statins (3-hydroxymethylglutaryl-coenzyme A reductase inhibitors). This study evaluated the influence of pravastatin on lipoprotein subclass profiles to determine whether subjects with predominantly large LDL (LDL size >20.5 nm) or small LDL (LDL size < or =20.5 nm) at baseline differ in responsiveness to drug treatment. Frozen plasma specimens were analyzed from a subset of participants in the Pravastatin Limitation of Atherosclerosis in the Coronaries (PLAC-I) trial at baseline and after treatment for 6 months with pravastatin (n=154) or placebo (n=138). Lipids were measured by standard chemical methods and lipoprotein subclasses by nuclear magnetic resonance (NMR) spectroscopy. Pravastatin-induced changes in lipid levels were similar in subjects with large or small LDL at baseline. Levels of the most abundant LDL subclass were preferentially lowered by pravastatin, resulting in an increase in average LDL size for those with a predominance of small LDL. High-risk CHD subjects with small LDL particles gain at least as much pharmacological benefit from pravastatin as those with large LDL, as evidenced by reductions in the numbers of total and small LDL particles, and increases in average LDL and HDL particle size.

Fluvastatin lowers atherogenic dense low-density lipoproteins in postmenopausal women with the atherogenic lipoprotein phenotype

BACKGROUND

Although HMG-CoA reductase inhibitors (HMGRIs) are effective lipid-lowering agents, it remains controversial whether these agents also lower dense LDL (dLDL), a predominance of which is considered to contribute to the atherogenicity of the metabolic syndrome.

METHODS AND RESULTS

In a multicenter, double-blind, randomized, placebo-controlled study, we determined the effect of the HMGRI fluvastatin on lipids, apolipoproteins, and LDL subfractions (by equilibrium density gradient ultracentrifugation). A total of 52 postmenopausal women with combined hyperlipidemia and increased dLDL were treated with either fluvastatin 40 mg/d (n=35) or placebo (n=17). After 12 weeks' treatment, significant reductions (P<0.001) in total cholesterol (-19%), IDL cholesterol (-35%), LDL cholesterol (-23%), apolipoprotein B (-21%), and apolipoprotein B in dLDL (-42%) were apparent among fluvastatin recipients. No significant changes in triglycerides or HDL cholesterol were observed. The effect of fluvastatin on dLDL was correlated with baseline values. There was no consistent relationship, however, between the effect of fluvastatin on triglycerides and the decrease in dLDL.

CONCLUSIONS

Fluvastatin lowers total and LDL cholesterol and the concentration of dLDL. This profile may contribute to an antiatherogenic effect for fluvastatin that is greater than expected on the basis of changes in lipids and apolipoproteins.

Comparative effects of cerivastatin and fenofibrate on the atherogenic lipoprotein phenotype in proteinuric renal disease

Patients with nephrotic-range proteinuria have impaired clearance of triglyceride-rich lipoproteins. This results in the atherogenic lipoprotein phenotype (mild hypertriglyceridemia, low high-density lipoproteins [HDL], and excess small, dense low-density lipoproteins [LDLIII]). Excess remnant lipoproteins (RLP) are linked to hypertriglyceridemia and may contribute to the atherogenicity of nephrotic dyslipidemia. A randomized crossover study compared the effects of a statin (cerivastatin) and a fibrate (fenofibrate) on LDLIII and RLP in 12 patients with nephrotic-range proteinuria. Cerivastatin reduced cholesterol (21%, P: < 0.01), triglyceride (14%, P: < 0.05), LDL cholesterol (LDL-C; 23%, P: < 0.01), total LDL (18%, P: < 0.01), and LDLIII concentration (27% P: < 0.01). %LDLIII, RLP-C, and RLP triglyceride (RLP-TG) were unchanged. Plasma LDLIII reduction with cerivastatin treatment correlated with LDL-C reduction (r(2) = 34%, P: < 0.05). Fenofibrate lowered cholesterol (19%), triglyceride (41%), very low-density lipoprotein cholesterol (52%), LDLIII concentration (49%), RLP-C (35%), and RLP-TG (44%; all P: < 0.01). Fenofibrate also reduced %LDLIII from 60 to 33% (P: < 0.01). HDL-C (19%, P: < 0.01) increased with fenofibrate treatment; LDL-C and total LDL were unchanged. The reduction in LDLIII concentration and RLP-C with fenofibrate treatment correlated with plasma triglyceride reduction (LDLIII r(2) = 67%, P: < 0.001; RLP cholesterol r(2) = 58%, P: < 0.005). Serum creatinine increased with fenofibrate treatment (14%, P: < 0.01); however, creatinine clearance was unchanged. LDLIII concentration was 187 +/- 85 mg/dl after cerivastatin treatment and 133 +/- 95 mg/dl after fenofibrate treatment. Cerivastatin and fenofibrate reduce LDLIII concentration in nephrotic-range proteinuria. However, atherogenic concentrations of LDLIII remain prevalent after either treatment. Fenofibrate but not cerivastatin reduces remnant lipoproteins. The two treatments seem to reduce LDLIII by different mechanisms, suggesting a potential role for combination therapy to optimize lowering of LDLIII and RLP.

Susceptibility to oxidation of plasma low-density lipoprotein in X-linked adrenoleukodystrophy: effects of simvastatin treatment

This paper shows for the first time the higher oxidizability of low-density lipoprotein (LDL) in plasma from adrenoleukodystrophy (ALD) patients compared to that of control subjects. LDL oxidation susceptibility was assessed by conjugate diene formation, hydroperoxide and lipoperoxide formation, and electrophoretic mobility. Simvastatin therapy, an HMG-CoA reductase inhibitor, seems to be a protective pharmacological agent against the higher oxidizability of LDL in plasma from ALD patients.

The effect of concentrated n-3 fatty acids versus gemfibrozil on plasma lipoproteins, low density lipoprotein heterogeneity and oxidizability in patients with hypertriglyceridemia

We evaluated in a double-blind randomized trial with a double-dummy design in 28 patients with primary hypertriglyceridemia, the effect of gemfibrozil (1200 mg/day) versus Omacor (4 g/day), a drug containing the n-3 fatty acids eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), on lipid and lipoprotein levels, low density lipoprotein (LDL) subfraction profile and LDL oxidizability. Both Omacor and gemfibrozil therapy resulted in a similar significant decrease in serum triglyceride (TG), very low density lipoprotein (VLDL) triglyceride and VLDL cholesterol concentrations and an increase in high density lipoprotein (HDL) and LDL cholesterol concentrations. The increase in LDL cholesterol was due to a significant increase in cholesterol content of the relatively buoyant LDL subfractions LDL1, LDL2 and LDL3, whereas the relative contribution of the dense LDL subfractions LDL4 and LDL5 to total LDL tended to decrease. So, both therapies resulted in a more buoyant LDL subfraction profile, reflected by a significant increase of the value of parameter K (+10.3% on Omacor vs. +26.5% on gemfibrozil therapy, gemfibrozil vs Omacor P>0.05). Cu(2+)-induced oxidation of LDL was measured by continuous monitoring of conjugated dienes. After 12 weeks of Omacor treatment LDL appeared more prone to oxidative modification in vitro than LDL after gemfibrozil treatment, as measured by the significantly decreased lag time, preceding the onset of the lipid peroxidation. In both groups the rate of oxidation did not change with therapy. The amount of dienes formed during oxidation increased significantly on Omacor treatment, but not on gemfibrozil treatment. Plasma thiobarbituric acid reactive substances were higher after Omacor and lower after gemfibrozil treatment, although not significantly. We conclude that both Omacor and gemfibrozil have favorable effects on lipid and lipoprotein concentrations and the LDL subfraction profile. However, Omacor increased the susceptibility of LDL to oxidation, whereas gemfibrozil did not affect the resistance of LDL to oxidative modification in vitro. The clinical relevance of these changes remains to be established in the light of other postulated favorable effects of n-3 fatty acids on the course of cardiovascular disease.

Normal oxidative stress and enhanced lipoprotein resistance to in vitro oxidation in hypertriglyceridemia: effects of bezafibrate therapy

Although there is evidence that hyperlipidemia and predominance of small dense low density lipoproteins (LDLs) are associated with increased oxidative stress, the oxidation status in patients with hypertriglyceridemia (HTG) has not been studied in detail. Therefore, we studied urinary levels of F(2)-isoprostanes (8-isoprostaglandin F(2alpha) and 2,3-dinor-5,6-dihydro-8-isoprostaglandin F(2alpha)) and susceptibility of very low density lipoproteins (VLDLs) and LDLs to oxidation ex vivo in 18 patients with endogenous HTG and 20 matched control subjects. In addition, the effects of 6 weeks of bezafibrate therapy were assessed in a double-blind, placebo-controlled, crossover trial. Urinary levels of F(2)-isoprostanes were similar in the HTG and normolipidemic group. Bezafibrate caused an increase in 8-isoprostaglandin F(2alpha) (762+/-313 versus 552+/-245 ng/24 h for bezafibrate and placebo therapy, respectively; P=0.03), whereas 2,3-dinor-5, 6-dihydro-8-isoprostaglandin F(2alpha) levels tended to be increased (1714+/-761 versus 1475+/-606 ng/24 h for bezafibrate and placebo therapy, respectively; P=0.11). VLDLs and LDLs were more resistant to copper-induced oxidation in patients with HTG than in control subjects. Bezafibrate reversed the oxidation resistance to the normal range. In conclusion, these results indicate the following: (1) HTG is associated with normal in vivo oxidative stress and enhanced ex vivo resistance of lipoproteins to oxidation. (2) Bezafibrate reduces the resistance of lipoproteins to copper-induced oxidation and enhances oxidative stress in HTG patients.

Effects of policosanol treatment on the susceptibility of low density lipoprotein (LDL) isolated from healthy volunteers to oxidative modification in vitro

AIMS

The aim of this study was to investigate the effect of policosanol on the susceptibility of LDL-C to in vitro lipid peroxidation in human healthy volunteers.

METHODS

The effect of policosanol (5 and 10 mg day(-1) on LDL-C oxidation was studied in a double-blind, randomized, placebo-controlled trial conducted in 69 subjects. LDL-C samples isolated at baseline and after 8 weeks were subjected to in vitro tests of LDL-C oxidation. We tested the susceptibility of LDL-C to lipid peroxidation in a cell-free system by the addition of copper ions as well as in a more physiological system, macrophage-mediated oxidation.

RESULTS

At baseline all groups were well matched regarding all variables. After 8 weeks of therapy policosanol administered at 5 and 10 mg, significantly and in a dose-dependent manner increased the lag phase of conjugated diene generation (mean +/- s.d.) from 83.79+/-29.16 min to 94.90+/-25.50 min (5 mg day(-1)) and from 82.74+/-17.16 min to 129.89+/-35.71 min (10 mg day(-1)), while in the placebo group LDL-C oxidation did not change significantly. Policosanol (10 mg day(-1)), but not placebo, significantly decreased the rate of conjugated diene generation. Comparison with placebo after therapy also showed significant differences. Macrophage mediated-oxidation was also inhibited by policosanol as evident by measuring thiobarbituric acid reactive substances (TBARS). Policosanol (10 mg day(-1)) significantly lowered malondialdehyde (MDA) generation from 8.50+/-0.91 to 5.76+/- 1.01 nmol mg(-1) protein. Comparison with placebo after 5 and 10 mg day(-1) showed significant differences. Policosanol significantly lowered total cholesterol by 10.5% (5 mg day(-1)) and 12.4% (10 mg day(-1)) and LDL-C by 16.7% and 20.2%, respectively. Also, policosanol (10 mg day(-1)) increased HDL-C by 15.2%. Five subjects withdrew from the study, none because of adverse experiences. No clinical or blood biochemical drug-related disturbances were found.

CONCLUSIONS

The present study demonstrated that policosanol administered within its therapeutic dosage for lowering cholesterol (5 and 10 mg day(-1)), decreased the susceptibility of LDL-C to lipid peroxidation in vitro.

The V73M mutation in the hepatic lipase gene is associated with elevated cholesterol levels in four Dutch pedigrees with familial combined hyperlipidemia

Familial combined hyperlipidemia (FCHL) is a heritable lipid disorder characterized by multiple lipoprotein phenotypes within a single family. Previously, we have shown an increased incidence of mutations in the LPL gene which was associated with elevated levels of very low density lipoprotein (VLDL) and decreased levels of high density lipoprotein among the families studied. Now, we report the results of our study on the hepatic lipase gene. We found the HL V73M variant to be present in four FCHL families. By means of a pedigree-based maximum log-likelihood method we analyzed the effect of this variant on the lipid levels in these families. Carriers of the HL V73M variant revealed significantly higher levels of total cholesterol (P < 0.01) and apoB (P <0.01). These findings show that the HL V73M mutant explains another part of the variability in the phenotype observed among FCHL family members, compared with mutations in the LPL gene. Family analysis shows that in these FCHL families, carriers of mutations in the LPL or HL genes have an increased risk for FCHL compared with their non-carrier relatives.

Omacor in familial combined hyperlipidemia: effects on lipids and low density lipoprotein subclasses

Elevations of plasma cholesterol and/or triglycerides, and the prevalence of small, dense LDL particles remarkably increase coronary risk in patients with familial combined hyperlipidemia (FCHL). A total of 14 FCHL patients were studied, to investigate the ability of Omacor, a drug containing the n-3 fatty acids eicosapentaenoic and docosahexaenoic acid (EPA and DHA), to favorably correct plasma lipid/lipoprotein levels and LDL particle distribution. The patients received four capsules daily of Omacor (providing 3.4 g EPA+DHA per day) or placebo for 8 weeks in a randomized, double-blind, cross-over study. Omacor significantly lowered plasma triglycerides and VLDL-cholesterol levels, by 27 and 18%, respectively. Total cholesterol did not change but LDL-cholesterol and apolipoprotein B (apoB) concentrations increased by 21 and 6%. As expected, LDL particles were small (diameter=24.9+/-0.3 nm) and apoB-rich (LDL-cholesterol/apoB ratio=1.27+/-0.26) in the selected subjects. After Omacor treatment LDL became enriched in cholesterol (LDL-cholesterol/apoB ratio=1.40+/-0.17), mainly cholesteryl esters, indicating accumulation in plasma of more buoyant and core enriched LDL particles. Indeed, the separation of LDL subclasses by rate zonal ultracentrifugation showed an increase of the plasma concentration of IDL and of the more buoyant, fast floating LDL-1 and LDL-2 subclasses after Omacor, with a parallel decrease in the concentration of the denser, slow floating LDL-3 subclass. However, the average LDL size did not change after Omacor (25.0+/-0.3 nm). The resistance of the small LDL pattern to drug-induced modifications implies that a maximal lipid-lowering effect must be achieved to reduce coronary risk in FCHL patients.

Current perspectives on statins

Statins (HMG-CoA reductase inhibitors) are used widely for the treatment of hypercholesterolemia. They inhibit HMG-CoA reductase competitively, reduce LDL levels more than other cholesterol-lowering drugs, and lower triglyceride levels in hypertriglyceridemic patients. Statins are well tolerated and have an excellent safety record. Clinical trials in patients with and without coronary heart disease and with and without high cholesterol have demonstrated consistently that statins reduce the relative risk of major coronary events by approximately 30% and produce a greater absolute benefit in patients with higher baseline risk. Proposed mechanisms include favorable effects on plasma lipoproteins, endothelial function, plaque architecture and stability, thrombosis, and inflammation. Mechanisms independent of LDL lowering may play an important role in the clinical benefits conferred by these drugs and may ultimately broaden their indication from lipid-lowering to antiatherogenic agents.

Low-density lipoprotein-independent effects of statins

Statins have pleiotropic properties that complement their cholesterol-lowering effects. These properties may partly account for their established benefit in the prevention of coronary artery disease beyond the reduction of LDL-cholesterol levels. The most widely recognized properties are reviewed here. They include: (i) nitric oxide-mediated improvement of endothelial dysfunction and upregulation of endothelin-1 expression; (ii) antioxidant effects; (iii) anti-inflammatory properties; (iv) inhibition of cell proliferation with anticarcinogenic actions in animals; (v) stabilization of atherosclerotic plaques; (vi) anticoagulant effects; and (vii) inhibition of graft rejection after heart and kidney transplantation. As advances are made in our knowledge, new properties are steadily being uncovered. Pleiotropic effects are currently being given consideration when instituting combination therapy for patients at high cardiovascular risk. Some pleiotropic effects are negative, and may account for occasional untoward drug interactions. For many of these new properties, the clinical relevance has not been established. The challenge for the future will be to design and carry out appropriate clinical trials to establish their relative importance in the prevention of coronary artery disease.

The rebound of lipoproteins after LDL-apheresis. Effects on chemical composition and LDL-oxidizability

The changes in low density lipoprotein (LDL) composition and oxidizability after LDL-apheresis (LA) using dextran sulfate cellulose columns were evaluated in 12 hypercholesterolemic men (mean+/-S.D. total cholesterol (TC) 9.7+/-1.8 mmol/l). After 10-20 months on biweekly LA combined with simvastatin 40 mg per day immediate pre-apheresis levels of TC, LDL-cholesterol, and apolipoprotein B were decreased to 5.3+/-1.3 mmol/l, 3.3+/-1.2 mmol/l, and 1.6+/-0.4 g/l, respectively, whereas apheresis induced mean acute reductions of 61, 78, and 76%, respectively. Measurements of copper-induced LDL-oxidizability in vitro showed an increased resistance against oxidation after LA until day 3 post-treatment: lag time (min) (day 0 (before LA) versus day 1 (post-LA)) 112+/-27 versus 130+/-26 (P=0.001), maximal rate of diene production (nmol/min per mg LDL) 11.1+/-2.7 versus 9.1+/-2.1 (P=0.001), and time to maximal diene production (min) 186+/-39 versus 209+/-35 (P=0. 001). Analysis of the chemical composition of LDL revealed a 25% (P<0.001) reduced content of cholesteryl esters and a decrease of the cholesterol to protein ratio of 1.20+/-0.25 to 0.70+/-0.22 (P<0. 001) through the 3rd day post-LA. Linoleic acid and arachidonic acid content of LDL decreased 11 and 18%, respectively, at the expense of palmitic acid. Vitamin E levels (mg/l) were significantly lowered due to reduction of the lipoprotein pool by apheresis; however, vitamin E content of LDL did not change in the days after apheresis when expressed per g protein or per micromol linoleic acid. The changes in fatty acid pattern were strongly associated with changes in LDL-oxidizability indices (P</=0.01). Thus, LA effectively decreased LDL pool size, inducing the presence of less buoyant lipoproteins, which were less susceptible to in vitro oxidation. This was not explained by changes in vitamin E levels, but by short-term changes in the fatty acids composition.

Effects of lovastatin therapy on susceptibility of LDL to oxidation during alpha-tocopherol supplementation

A randomized, double-masked, crossover clinical trial was carried out to evaluate whether lovastatin therapy (60 mg daily) affects the initiation of oxidation of low density lipoprotein (LDL) in cardiac patients on alpha-tocopherol supplementation therapy (450 IU daily). Twenty-eight men with verified coronary heart disease and hypercholesterolemia received alpha-tocopherol with lovastatin or with dummy tablets in random order. The two 6-week, active-treatment periods were preceded by a washout period of at least 8 weeks. The oxidizability of LDL was determined by 2 methods ex vivo. The depletion times for LDL ubiquinol and LDL alpha-tocopherol were determined in timed samples taken during oxidation induced by 2, 2-azobis(2,4-dimethylvaleronitrile). Copper-mediated oxidation of LDL isolated by rapid density-gradient ultracentrifugation was used to measure the lag time to the propagation phase of conjugated-diene formation. alpha-Tocopherol supplementation led to a 1.9-fold concentration of reduced alpha-tocopherol in LDL (P<0.0001) and to a 2.0-fold longer depletion time (P<0.0001) of alpha-tocopherol compared with determinations after the washout period. A 43% prolongation (P<0.0001) was seen in the lag time of conjugated-diene formation. Lovastatin decreased the depletion time of reduced alpha-tocopherol in metal ion-independent oxidation by 44% and shortened the lag time of conjugated-diene formation in metal ion-dependent oxidation by 7%. In conclusion, alpha-tocopherol supplementation significantly increased the antioxidative capacity of LDL when measured ex vivo, which was partially abolished by concomitant lovastatin therapy.

Plasma lipoprotein distribution and lipid transfer activities in patients with type IIb hyperlipidemia treated with simvastatin

The aim of the present study was to search in type IIb hyperlipidemic patients for putative concomitant effects of simvastatin on the physicochemical characteristics of low density lipoproteins (LDL) and high density lipoproteins (HDL), as well as on the activities of the cholesteryl ester transfer protein (CETP) and the phospholipid transfer protein (PLTP) that were determined in both endogenous lipoprotein-dependent and endogenous lipoprotein-independent assays. In a double-blind, randomized trial, patients received either placebo (one tablet/day; n = 12) or simvastatin (20 mg/day; n = 12) for a period of 8 weeks after a 5-week run-in period. Simvastatin, unlike placebo, reduced the lipid and apolipoprotein B contents of the most abundant LDL-1, LDL-2, and LDL-3 subfractions without inducing significant changes in the overall size distribution of LDL and HDL. Whereas simvastatin significantly increased PLTP activity in an endogenous lipoprotein-dependent assay (P < 0.01), no variation was observed in a lipoprotein-independent assay. Simvastatin significantly decreased plasma CETP activity in an endogenous lipoprotein-dependent assay (P < 0.01), and the reduction in plasma cholesteryl ester transfer rates was explained by a 16% drop in CETP mass concentration (P < 0.01). In contrast, the specific activity of CETP was unaffected by the simvastatin treatment reflecting at least in part the lack of significant alteration in plasma triglyceride-rich lipoprotein acceptors. The simvastatin-induced changes in plasma CETP mass levels correlated positively with changes in plasma CETP activity (r = 0.483, P = 0.0561), in total cholesterol levels (r = 0.769; P < 0.01), and in LDL-cholesterol levels (r = 0.736; P < 0.01). Whereas the observations suggest that simvastatin might exert concomitant beneficial effects on plasma CETP and LDL levels, neither plasma cholesteryl ester transfer activity nor plasma phospholipid transfer activity appeared as the main determinants of the LDL and HDL distribution profiles in type IIb hyperlipidemic patients.

Simvastatin decreases aldehyde production derived from lipoprotein oxidation

Treatment with statins are known to lower plasma and low-density lipoprotein (LDL) cholesterol levels with resultant prevention and regression of atherosclerosis. It has been recently suggested that the action of the statins may also have a direct effect on other mechanisms involved in the atherosclerotic plaque formation. Thus, we investigated whether simvastatin could have an antioxidant effect on plasma lipoproteins. The rate of oxidation of LDL and high-density lipoproteins (HDL) was measured by conjugated diene formation with and without the addition of increasing concentrations of simvastatin (in vitro) and in patients with and without treatment with simvastatin (in vivo). A strong correlation was observed between increasing simvastatin concentration and the lag phase, a negative correlation was observed for maximal rate and maximum diene production in LDL samples (r2 = +0.97, p <0.0001; r2 = -0.92, p <0.0001; r2 = -0.98, p <0.0001, respectively). For HDL no clear correlation could be established with the lag phase, but a strong negative correlation was also observed between simvastatin concentration and maximal rate and maximum diene production (r2 = -0.69, p <0.01; r2 = -0.98, p <0.0001, respectively). After 6 hours of oxidation the production of aldehydes in LDL and HDL was lower (30% and 5%, respectively) in samples obtained during simvastatin therapy with respect to those obtained without treatment. The 2,4-decadienal showed a decrease of 37% and 64% (p <0.05) in both oxidized-LDL and oxidized-HDL particles, respectively, with simvastatin treatment. Our findings demonstrate that simvastatin acts as an antioxidant in lipoprotein particles and, together with its lipid-lowering properties, could play an important role in preventing atherosclerosis.

Randomized crossover study of gemfibrozil versus lovastatin in familial combined hyperlipidemia: additive effects of combination treatment on lipid regulation

The most appropriate therapy for combined hyperlipidemia remains to be determined. We compared the lipid-regulating effects of gemfibrozil and lovastatin in 30 patients with familial combined hyperlipidemia (FCHL) in a randomized, double-blind, placebo-controlled crossover study including 8-week courses of one drug followed by a washout period and a crossover phase to the alternate drug. After completion of the trial, open-label combination therapy was given for up to 12 months. Lovastatin was more efficacious than gemfibrozil in the reduction of total cholesterol (23% v. 9%, P<.001) and low-density lipoprotein (LDL) cholesterol (28% v. 2%, P<.001), whereas gemfibrozil surpassed lovastatin in the reduction of triglycerides (48% v. 0%, P<.001) and very-low-density lipoprotein (VLDL) cholesterol (50% v. 19%, P = .005) and the increase of high-density lipoprotein (HDL) cholesterol (18% v. 4%, P = .005). Lovastatin caused a greater decline in total apolipoprotein B (apo B) and LDL apo B than gemfibrozil, whereas VLDL apo B decreased only after gemfibrozil therapy. Drug-induced changes in lipoprotein composition indicated that gemfibrozil reduced both the number and size of VLDL particles and lovastatin decreased the number of LDL particles. Combined treatment was safe and had additive effects on lipids, causing significant (P<.001) reductions in total cholesterol (32%), triglycerides (51%), LDL cholesterol (34%), and apo B (26%) and an increase in HDL cholesterol (19%). Target LDL cholesterol levels were achieved only in 11% of patients given gemfibrozil alone and triglycerides decreased to target levels in 22% after lovastatin alone, whereas combined therapy normalized both lipid fractions in 96% of patients. Thus, in FCHL, gemfibrozil has no effect on LDL cholesterol levels but favorably influences the putative atherogenic alterations of lipoprotein composition that are related to hypertriglyceridemia. Conversely, lovastatin markedly decreases LDL cholesterol but has little effect on triglyceride-rich lipoproteins. Combination treatment safely corrects all of the lipid abnormalities in most patients.

Association between low-density lipoprotein composition and its metabolism in non-insulin-dependent diabetes mellitus

Atheroma is related to low-density lipoprotein (LDL) composition. LDL in diabetic patients-a group with increased risk of severe atheroma-has been shown by our group and others to have various compositional alterations that are potentially atherogenic. Little is known about the relationship between LDL turnover and composition. This study examined the relationship between LDL composition and turnover in non-insulin-dependent diabetes mellitus (NIDDM) patients. Twenty-two NIDDM patients with a mean plasma cholesterol of 6.6+/-1.5 mmol/L were studied. Twelve subjects were hypercholesterolemic (mean cholesterol, 7.7+/-0.8 mmol/L), and eight of these agreed to be studied a second time after 4 weeks of treatment with simvastatin. LDL was isolated by density gradient ultracentrifugation, iodinated, and reinjected into the patient. LDL turnover was determined by measuring the clearance of [125I]-LDL from plasma over a 10-day period. The LDL residence time, determined using a biexponential model, correlated negatively with the body mass index (BMI) (r = -.73, P<.001) and serum triglycerides (r = - .57, P<.01). There was a significant inverse correlation between LDL residence time and the LDL esterified to free cholesterol ratio in hypercholesterolemic subjects (r = -.94, P<.001). There was a significant inverse relationship between LDL residence time and both hemoglobin A1c (HbA1c) and fasting blood glucose in these subjects before treatment (P<.005). After simvastatin therapy, the relationships were no longer significant. Simvastatin treatment was associated with a shorter LDL residence time (P<.01) and a decrease in LDL glycation (P<.001) with virtually no change in diabetic control (HbA1c, 6.0%+/-3.1% v. 6.3%+/-3.3%, NS). This study suggests that a decrease in residence time by upregulation of the LDL receptor with simvastatin alters LDL composition in a way that is likely to render the particle less atherogenic.

Effect of gemfibrozil on serum levels of prostacyclin and precursor fatty acids in hyperlipidemic patients with Type 2 diabetes

Lipid-lowering fibrate drugs are known to affect the synthesis of fatty acids, which may alter the prostacyclin synthesis in diabetic patients. Therefore, the serum levels of precursor fatty acids and 6-keto-prostaglandin F1alpha (6-keto PGF1alpha) were determined in ten hyperlipidemic patients with Type 2 diabetes before and after administration of gemfibrozil (900 mg/day) for 3 months, in comparison with the results in seven non-diabetic hyperlipidemic patients. Gemfibrozil significantly reduced the serum concentration of dihomo-7-linolenic acid, total cholesterol and triglycerides, but did not affect the serum levels of arachidonic acid and 6-keto PGF1alpha in diabetic and non-diabetic patients. Thus, gemfibrozil did not affect the synthesis of prostacyclin in spite of the reduction of precursor fatty acids in diabetic and non-diabetic patients.