Residual effects of lovastatin and simvastatin on urinary mevalonate excretions in patients with familial hypercholesterolemia

3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG CoA) reductase inhibitors are widely used to decrease plasma cholesterol levels in patients with heterozygous familial hypercholesterolemia (FH) who are at increased risk of premature coronary artery disease. Tissue-culture and animal studies have indicated that administration of HMG CoA reductase inhibitors (eg, lovastatin, simvastatin, etc) induces a compensatory increase in the activity of HMG CoA reductase, both by increasing its synthesis and decreasing catabolism. To determine in human subjects whether cessation of therapy with this class of drugs leads to induction of HMG CoA reductase activity and above-normal rates of cholesterol biosynthesis, we measured urinary concentrations of mevalonic acid (an indicator of cholesterol biosynthesis) after the cessation of therapy with lovastatin and simvastatin (80 mg/day) in patients with heterozygous FH. Plasma concentrations of LDL increased promptly on discontinuation of reductase inhibitor therapy but did not increase above pretreatment levels at any point after drug discontinuation. Similarly, the 24-hour urinary excretion of mevalonic acid was reduced during treatment with lovastatin or simvastatin and increased promptly on discontinuation of drug but did not increase to levels exceeding those found at baseline when the patients were receiving dietary therapy only. We conclude that cessation of treatment with HMG CoA reductase inhibitors in patients with FH does not result in a rebound increase in cholesterol biosynthesis and that no rebound overshoot occurs in plasma concentrations of low-density-lipoprotein cholesterol.     

Contrasting effects of lovastatin and cholestyramine on low-density lipoprotein cholesterol and 24-hour urinary mevalonate excretion in patients with heterozygous familial hypercholesterolemia

To further validate the usefulness of quantitative measurements of urinary mevalonic acid excretion as an indicator of rates of cholesterol biosynthesis, we have determined the 24-hour urinary excretion of mevalonic acid in patients with heterozygous familial hypercholesterolemia treated with drugs that have opposing effects on cholesterol biosynthesis. In patients with familial hypercholesterolemia treated with the bile acid sequestrant cholestyramine (16 gms/day), urinary mevalonate excretion increased by 28%, whereas low-density lipoprotein cholesterol concentrations decreased by 21%. In patients with familial hypercholesterolemia treated with the 3-hydroxy 3-methyl glutaryl coenzyme A reductase inhibitor lovastatin (80 mg/day), concentrations of low-density lipoprotein cholesterol and the urinary excretion of mevalonate both decreased (by 40% and 34%, respectively). When cholestyramine was used in combination with lovastatin, low-density lipoprotein cholesterol levels decreased by an additional 14% as compared to monotherapy with lovastatin; urinary mevalonate excretion rose by (25%), but the magnitude of this increase was not statistically significant. We conclude that rates of excretion of urinary mevalonic acid (which may reflect rates of whole body cholesterol biosynthesis) in patients with FH decrease on therapy with lovastatin and increase in response to cholestyramine treatment. When used in combination, these drugs counteract each other's effects on cholesterol synthesis, but low-density lipoprotein cholesterol concentrations decrease further. Measurement of urinary mevalonate excretion affords a practical means of assessing the comparable effects of different dietary or pharmaceutical manipulations on cholesterol biosynthesis in human beings.     

Simvastatin decreases the hepatic secretion of very-low-density lipoprotein apolipoprotein B-100 in heterozygous familial hypercholesterolaemia: pathophysiological and therapeutic implications

Abstract. We studied six patients with heterozygous familial hypercholesterolaemia (FH) before and after 8 weeks of treatment with simvastatin (40 mg day^-1), an inhibitor of 3-hydroxy-3-methyl-glutaryl-Coenzyme A. Simvastatin decreased plasma low-density lipoprotein (LDL) cholesterol by 43% ( P = 0.002), triglycerides by 27% ( P = 0.05) and mevalonic acid (a measure of in vivo cholesterol synthesis) by 20% ( P = 0.002); high-density lipoprotein cholesterol increased by 17% ( P = 0.02). The hepatic secretion rate of very-low-density lipoprotein apolipoprotein B-100 (VLDL apoB) was measured directly using a primed, constant intravenous infusion of l-[¹³C]-leucine with monitoring of the isotopic enrichment of apoB by gas chromatography-mass spectrometry; fractional secretion rate (FSR) was derived using a mono-exponential function. Simvastatin decreased the FSR, ASR and pool size of VLDL apoB by 17% (14.3 (SEM 3.6)) vs. (11.9 (SEM 3.5) pools day^-1, P = 0.10), 83% (51.4 (SEM 17.9) vs. (8.6 (SEM 1.4), P = 0.007mgkg^-1day^-1) and 65% (234.2 (SEM 30.4) vs. 82.6 (SEM 24.0)mg, P = 0.02), respectively. The change in the ASR of VLDL apoB was significantly correlated with the change in plasma LDL cholesterol concentration ( P = 0.04), but not with the change of triglyceride or mevalonic acid. We conclude that the hepatic secretion of VLDL apoB in FH is decreased by simvastatin, which may partly explain the fall in plasma cholesterol. This effect does not appear to be directly related to the inhibition of cholesterol synthesis and may be due to decreased hepatic delivery of cholesterol esters via the LDL receptor-independent pathway, but these mechanisms require further investigation.     

A systematic review and meta‐analysis on the therapeutic equivalence of statins

Background: Statins are the most commonly prescribed agents for hypercholesterolemia because of their efficacy and tolerability. As the number of patients in need of statin therapy continues to increase, information regarding the relative efficacy and safety of statins is required for decision‐making. Objective: This study will use systematic review to compare the efficacy and safety profiles of different statins at different doses and determine the therapeutically equivalent doses of statins to achieve a specific level of low‐density lipoprotein cholesterol (LDL‐C) lowering effect. Methods: Publications of head‐to‐head randomized controlled trials (RCTs) of statins were retrieved from the Oregon state database (1966–2004), MEDLINE (2005‐April of 2006), EMBASE (2005‐April of 2006), and the Cochrane Controlled Trials Registry (up to the first quarter of 2006). The publications were evaluated with predetermined criteria by a reviewer before they were included in the review. The mean change in cholesterol level of each statin was calculated and weighted by number of subjects involved in each RCT. Where possible, meta‐analysis was performed to generate pooled estimates of the cholesterol lowering effect of statins and the difference between statins. Results: Seventy‐five studies reporting RCTs of head‐to‐head comparisons on statins were included. Most studies had similar baseline characteristics, except the rosuvastatin related studies. A daily dose of atorvastatin 10 mg, fluvastatin 80 mg, lovastatin 40–80 mg, and simvastatin 20 mg could decrease LDL‐C by 30–40%, and fluvastatin 40 mg, lovastatin 10–20 mg, pravastatin 20–40 mg, and simvastatin 10 mg could decrease LDL‐C by 20–30%. The only two statins that could reduce LDL‐C more than 40% were rosuvastatin and atorvastatin at a daily dose of 20 mg or higher. Meta‐analysis indicated a statistically significant but clinically minor difference (<7%) between statins in cholesterol lowering effect. Comparisons of coronary heart disease prevention and safety could not be made because of insufficient data. Conclusions: At comparable doses, statins are therapeutically equivalent in reducing LDL‐C.     

The evolution and revolution of the implantable cardioverter defibrillator

A low-density lipoprotein (LDL) cholesterol goal of less than 100 mg/dl is recommended for patients at moderate to high risk of cardiovascular disease with an optional LDL goal of less than 70 mg/dl for patients at a very high risk of cardiovascular disease. Most patients will require reductions in LDL of more than 50% in order to achieve these more aggressive goals. Only a few agents will lower LDL by at least 50%. This review will focus on the efficacy and safety ezetimibe/simvastatin coadministered as a therapy with enhanced LDL-lowering efficacy, while minimizing the adverse effects of statins in a wide range of patients. Ezetimibe 10 mg/simvastatin 80 mg lowers LDL by approximately 60% and has been demonstrated to be superior to the highest doses of atorvastatin and rosuvastatin for lowering LDL and raising high-density lipoprotein.     

Combination therapy with ezetimibe and simvastatin to achieve aggressive LDL reduction

A low-density lipoprotein (LDL) cholesterol goal of less than 100 mg/dl is recommended for patients at moderate to high risk of cardiovascular disease with an optional LDL goal of less than 70 mg/dl for patients at a very high risk of cardiovascular disease. Most patients will require reductions in LDL of more than 50% in order to achieve these more aggressive goals. Only a few agents will lower LDL by at least 50%. This review will focus on the efficacy and safety ezetimibe/simvastatin coadministered as a therapy with enhanced LDL-lowering efficacy, while minimizing the adverse effects of statins in a wide range of patients. Ezetimibe 10 mg/simvastatin 80 mg lowers LDL by approximately 60% and has been demonstrated to be superior to the highest doses of atorvastatin and rosuvastatin for lowering LDL and raising high-density lipoprotein.     

Effects of ezetimibe/simvastatin on lipoprotein subfractions in patients with primary hypercholesterolemia: an exploratory analysis of archived samples using two commercially available techniques

BACKGROUND: Cholesterol-rich lipoproteins, including low-density lipoprotein cholesterol (LDL-C), intermediate-density lipoprotein cholesterol (IDL-C), and very-low-density lipoprotein cholesterol (VLDL-C), are known to promote atherosclerosis. Ezetimibe/simvastatin (E/S) is an efficacious lipid-lowering treatment that inhibits both the intestinal absorption and biosynthesis of cholesterol. OBJECTIVE: The aim of the current analysis was to compare the effects of ezetimibe and simvastatin monotherapy and E/S treatment on lipoprotein subfractions and LDL particle size in patients with primary hypercholesterolemia. METHODS: This was an exploratory (hypothesis generating) analysis of archived plasma samples drawn from patients in a multicenter, randomized, double-blind, placebo-controlled, parallel-arm study. After a washout and diet/placebo run-in, patients with hypercholesterolemia (LDL-C, > or =145- < or =250 mg/dL; triglycerides, < or =350 mg/dL) were randomized equally to 1 of 10 daily treatments for 12 weeks: E/S (10/10, 10/20, 10/40, or 10/80 mg), simvastatin monotherapy (10, 20, 40, or 80 mg), ezetimibe monotherapy (10 mg), or placebo. A subset of patients had lipid subfraction measurements taken at baseline (week 0) and postrandomization (week 12). Plasma samples were used to quantify cholesterol associated with VLDL subfractions (VLDLI+2 and VLDL3), IDL, and 4 LDL subfractions (LDL1-4) via the Vertical Auto Profile II method. LDL-C particle size was determined using segmented gradient gel electrophoresis. The primary end point was median percent change in subfraction cholesterol for E/S versus ezetimibe or simvastatin monotherapy, pooled across doses. RESULTS: Of the 1528 patients randomized in the original study, 1397 (91%) had lipid subfraction measurements taken. E/S was associated with significant reductions in VLDL-CI+2, VLDL-C3, IDL-C, LDL-C1, LDL-C2, and LDL-C3 versus ezetimibe, simvastatin, and placebo. E/S resulted in near-additive reductions in VLDL-CI+2, VLDL-C3, IDL-C, LDL-C1, LDL-C2, and LDL-C3 versus ezetimibe and simvastatin monotherapy. Of the subfractions examined, with regard to E/S, the greatest reductions were observed in IDL-C and LDL-C1, LDL-C2, and LDL-C3. When compared with placebo, ezetimibe, simvastatin, and E/S did not shift the distribution of LDL particles toward a larger, more buoyant LDL subclass pattern. CONCLUSION: E/S was more effective than ezetimibe and simvastatin monotherapy in reducing atherogenic lipoprotein subfractions in these patients with primary hypercholesterolemia.     

Effects of rosuvastatin versus atorvastatin, simvastatin, and pravastatin on non-high-density lipoprotein cholesterol, apolipoproteins, and lipid ratios in patients with hypercholesterolemia: additional results from the STELLAR trial

BACKGROUND: Non-high-density lipoprotein cholesterol (HDL-C), apolipoprotein (apo) B, and lipid and apolipoprotein ratios that include both atherogenic and antiatherogenic lipid components have been found to be strong predictors of coronary heart disease risk. OBJECTIVE: The goal of this study was to examine prospectively the effects of rosuvastatin, atorvastatin, simvastatin, and pravastatin across dose ranges on non-HDL-C, apo B, apo A-I, and total cholesterol (TC):HDL-C, low-density lipoprotein cholesterol (LDL-C):HDL-C, non-HDL-C:HDL-C, and apo B:apo A-I ratios in patients with hypercholesterolemia (LDL-C > or =160 mg/dL and <250 mg/dL and triglycerides <400 mg/dL) in the Statin Therapies for Elevated Lipid Levels compared Across doses to Rosuvastatin (STELLAR) trial. METHODS: In this randomized, Multicenter, parallel-group, open-label trial (4522IL/0065), patients > or =18 years of age received rosuvastatin 10, 20, 40, or 80 mg; atorvastatin 10, 20, 40, or 80 mg; simvastatin 10, 20, 40, or 80 mg; or pravastatin 10, 20, or 40 mg for 6 weeks. Pairwise comparisons were prospectively planned and performed between rosuvastatin 10, 20, and 40 mg and milligram-equivalent or higher doses of comparators. RESULTS: A total of 2268 patients were randomized to the rosuvastatin 10- to 40-mg, atorvastatin, simvastatin, and pravastatin groups. Fifty-one percent of patients were women, the mean (SD) age was 57 (12) years, and 19% had a documented history of atherosclerotic disease. Over 6 weeks, rosuvastatin significantly reduced non-HDL-C, apo B, and all lipid and apolipoprotein ratios assessed, compared with milligram-equivalent doses of atorvastatin and milligram-equivalent or higher doses of simvastatin and pravastatin (all, P < 0.002). Rosuvastatin reduced non-HDL-C by 42.0% to 50.9% compared with 34.4% to 48.1% with atorvastatin, 26.0% to 41.8% with simvastatin, and 18.6% to 27.4% with pravastatin. Rosuvastatin reduced apo B by 36.7% to 45.3% compared with 29.4% to 42.9% with atorvastatin, 22.2% to 34.7% with simvastatin, and 14.7% to 23.0% with pravastatin. The highest increase in apo A-I (8.8%) was observed in the rosuvastatin 20-mg group, and this increase was significantly greater than in the atorvastatin 40-mg and 80-mg groups (both, P < 0.002). CONCLUSION: Rosuvastatin 10 to 40 mg was more efficacious in improving the lipid profile of patients with hypercholesterolemia than milligram-equivalent doses of atorvastatin and milligram-equivalent or higher doses of simvastatin and pravastatin.     

Treatment with atorvastatin alters the ratio of interleukin-12/interleukin-10 gene expression [corrected

BACKGROUND: Statins have been shown to have pleiotropic effects extending beyond their ability to lower cholesterol. MATERIAL AND METHODS: Seventeen patients with heterozygous familial hypercholesterolaemia participated in a single-blind placebo controlled study. The patients underwent three treatment regimens: placebo (4 weeks), atorvastatin 10 mg day(-1) (4 weeks) and atorvastatin 40 mg day(-1) (12 weeks). Following each treatment period, serum lipids and plasma mevalonic acid were measured, mononuclear leukocytes were isolated and total RNA was prepared. The content of mRNA for IL-12p35 and IL-10 was assayed, blinded, by real-time quantitative polymerase chain reactions. RESULTS: Treatment of the subjects with atorvastatin decreased the abundance of IL-12p35 mRNA in mononuclear cells, but did not alter that of IL-10, so that the ratio of the IL-12p35 to IL-10 mRNA content was significantly reduced (P < 0.0026). The IL-12p35/IL-10 ratio correlated significantly with plasma mevalonic acid concentrations but not with serum LDL concentrations. CONCLUSIONS: This study provides evidence that atorvastatin exerts an immunomodulatory effect in vivo, characterized by a decrease in the ratio of IL-12 mRNA to IL-10 mRNA in leukocytes. The immunomodulatory effect of statins, in addition to their cholesterol-lowering properties, may contribute to the rapid cardiovascular benefit observed during treatment with statins and reduced the rate of rejection in patients with solid organ transplantation.     

Atorvastatin compared with simvastatin-based therapies in the management of severe familial hyperlipidaemias

We compared atorvastatin with simvastatin-based therapies in a prospective observational study of 201 patients with severe hyperlipidaemia. Atorvastatin 10 mg therapy was substituted for simvastatin 20 mg, 20 mg for 40 mg, 40 mg for simvastatin 40 mg plus resin, and 80 mg for simvastatin-fibrate-resin therapy. Lipid and safety profiles were assessed. Atorvastatin reduced total cholesterol by 31 +/- 11-40 +/- 14% vs. 25 +/- 12-31 +/- 11%; LDL by 38 +/- 16-45 +/- 18% vs. 31 +/- 18-39 +/- 18% and geometric mean triglycerides by 29.3-37.3% vs. 16.6-24.8%, but reduced HDL 11% +/- 47% at 80 mg compared with a 16% +/- 34% increase with simvastatin-based therapy. Target LDL < 3.5 mmol/l was achieved more often with atorvastatin (63% vs. 50%; p < 0.001). Atorvastatin increased geometric mean fibrinogen by 12-20% vs. a 0-6% fall with simvastatin (p < 0.001). Side effects were noted in 10-36% of patients, including one case of rhabdomyolysis, and 36% discontinued therapy. These data suggest that atorvastatin is more effective than current simvastatin-based therapies in achieving treatment targets in patients with familial hypercholesterolaemia but at the expense of a possible increase in side-effects. This issue needs further study in randomized controlled trials.     

Non-insulin-dependent diabetes mellitus: dietary monounsaturated fatty acids and low-density lipoprotein composition and function

Alterations in low-density lipoprotein (LDL) composition in diabetes affect its function with respect to control of de novo cholesterol synthesis. We examined the effect of 4 weeks of an oleic-acid-rich diet on LDL composition and function in eight Type 2 diabetic and eight non- diabetic control subjects. LDL (density 1.019-1.063 g/l) was isolated by sequential ultracentrifugation. LDL composition was measured and LDL fatty acids were determined by gas liquid chromatography. Cholesterol synthesis was measured by [14C]-acetate incorporation into the freshly isolated mononuclear leucocytes. Fasting blood glucose fell from 9.3 +/- 2.0 to 8.2 +/- 1.2 mmol/l (p < 0.05) and fasting serum insulin increased from 8.3 +/- 2.8 to 10.4 +/- 5.0 mIU/l (p > 0.05) in the diabetic patients. LDL oleic acid increased in the diabetic patients from 18.8 +/- 1.8% to 22.5 +/- 1.9% (p < 0.01) and in the non-diabetic subjects from 19.9 +/- 1.8% to 23.3 +/- 2.8% (p < 0.01). The LDL- esterified to free cholesterol ratios of 3.0 +/- 0.6 and 2.7 +/- 0.2 for the diabetic and non-diabetic patients were similar, and decreased significantly (p < 0.01) to 2.4 +/- 0.5 and 2.2 +/- 0.4, respectively. Baseline [14C]-acetate incorporation was similar in the two groups, and decreased after diet from 437 +/- 239 to 249 +/- 144 ng/g cell protein (p < 0.05) in the diabetic patients. There was a negative correlation between the LDL-esterified to free cholesterol ratio and the ratio of oleic to linoleic acid in the LDL (r = -0.39, p < 0.05) and a negative correlation between fasting blood glucose and LDL oleic acid in the diabetic patients (r = -0.51, p < 0.05). Enrichment of LDL with oleic acid appears to improve its ability to regulate endogenous cholesterol synthesis in both control and diabetic subjects. In the diabetic population, the diet had a favourable effect on glycaemic control.      

A Randomized Multicenter Trial Comparing and Efficacy of Simvastatin and Fluvastatin

BACKGROUND: Inhibitors of hydroxymethylglutaryl co-enzyme A reductase are widely used for the treatment of hypercholesterolemia. Physicians and third-party payers need an accurate measure of their relative potency and hypolipidemic efficacy. We have therefore compared simvastatin against fluvastatin, the newest member of this class. METHODS AND RESULTS: One hundred fifty-eight hypercholesterolemic patients in seven United States lipid clinics participated in this balanced double-blind incomplete block study. After a placebo-diet run-in period, patients received treatment with active drug for three consecutive 5-week periods, with measurement of lipids in a NHLBI-CDC standardized central laboratory at the end of each period. Each patient was randomly assigned to three of the following five treatments: simvastatin 5 mg, 10 mg, and 20 mg and fluvastatin 20 mg and 40 mg. The mean percent reductions in low density lipoprotein cholesterol from baseline were 21, 27, 32, 16, and 23 respectively. The simvastatin/fluvastatin milligram potency ratio was 6.8 (95% CI, 5.3-9.3). At the same 20 mg dose, simvastatin produced an effect on LDL cholesterol approximately double that of fluvastatin and resulted in 46% of patients achieving their National Cholesterol Education Program low density lipoprotein cholesterol target levels, compared to 12% for fluvastatin. CONCLUSIONS: Fluvastatin at its maximal dose of 40 mg daily is approximately equivalent to simvastatin 5 mg daily. Higher doses of simvastatin are considerably more effective in the treatment of primary hypercholesterolemia.     

Incremental cholesterol reduction with ezetimibe/simvastatin,atorvastatin and rosuvastatin in UK General Practice (IN‐PRACTICE): randomised controlled trial of achievement of Joint British Societies (JBS‐2) cholesterol targets

Aim: The aim of this study was to compare ezetimibe/simvastatin combination therapy with intensified statin monotherapy as alternative treatment strategies to achieve the Joint British Societies (JBS)‐2 and National Institute for Health and Clinical Excellence low‐density‐lipoprotein cholesterol (LDL‐C) target of < 2 mmol/l for secondary prevention or JBS‐2 LDL‐C target of < 2 mmol/l for primary prevention in high‐risk patients who have failed to reach target with simvastatin 40 mg. Methods: This is a prospective, double‐blind study conducted in 34 UK primary care centres; 1748 patients with established cardiovascular disease (CVD), diabetes or high risk of CVD who had been taking simvastatin 40 mg for ≥ 6 weeks were screened and 786 (45%) with fasting LDL‐C ≥ 2.0 mmol/l (and < 4.2 mmol/l) at screening and after a further 6‐week run‐in period on simvastatin 40 mg were randomised to ezetimibe/simvastatin 10/40 mg (as a combination tablet; n = 261), atorvastatin 40 mg (n = 263) or rosuvastatin 5 mg (n = 73) or 10 mg (n = 189) once daily for 6 weeks. Rosuvastatin dose was based on UK prescribing instructions. The primary outcome measure was the proportion of patients achieving LDL‐C < 2 mmol/l at the end of the study. Results: The percentage of patients (adjusted for baseline differences) achieving LDL‐C < 2 mmol/l was 69.4% with ezetimibe/simvastatin 10/40 mg, compared with 33.5% for atorvastatin 40 mg [odds ratio 4.5 (95% CI: 3.0–6.8); p < 0.001] and 14.3% for rosuvastatin 5 or 10 mg [odds ratio 13.6 (95% CI: 8.6–21.6); p < 0.001]. Similar results were observed for achievement of total cholesterol < 4.0 mmol/l. All study treatments were well tolerated. Conclusion: Approximately 45% of patients screened had not achieved LDL‐C < 2 mmol/l after ≥ 12 weeks of treatment with simvastatin 40 mg. In this group, treatment with ezetimibe/simvastatin 10/40 mg achieved target LDL‐C levels in a significantly higher proportion of patients during a 6‐week period than switching to either atorvastatin 40 mg or rosuvastatin 5–10 mg.     

Soybean protein diet increases low density lipoprotein receptor activity in mononuclear cells from hypercholesterolemic patients.

The effect of two diets containing different protein sources (animal vs. soybean) on the low density lipoprotein (LDL) receptor activity was tested in freshly isolated mononuclear cells from 12 individuals with severe type II hyperlipoproteinemia. The two diets, both taken for 4 wk in a crossover design were of otherwise identical composition. During the soybean protein diet period, total cholesterol was reduced by 15.9% and LDL-cholesterol by 16.4%. The diet containing animal proteins exerted no significant change in plasma lipid levels vs. the baseline findings. The soybean diet regimen dramatically affected the degradation of LDL by mononuclear cells. Degradation was increased 16-fold vs. the basal activity and 8-fold compared with the standard low lipid diet with animal proteins. There was, however, no clear relationship between the reduction of total and LDL-cholesterolemia and the increased LDL degradation. These findings confirm similar data previously obtained in cholesterol-fed rats and suggest that some factor/s, most likely of a protein nature, may regulate the expression of lipoprotein receptors in peripheral cells, particularly when receptor activity is suppressed by experimental diets and/or spontaneous hypercholesterolemia.     

Regulation of low density lipoprotein receptor activity in freshly isolated human lymphocytes.

Circulating human lymphocytes freshly isolated from venous blood of 15 normal subjects exhibited a low capacity to bind, take up, and degrade 125I-labeled low density lipoprotein (LDL). However, when these cells were incubated for 72 h in the absence of lipoproteins, they gradually acquired in increased number of high affinity cell surface receptors for LDL. The increase in the number of LDL receptors was associated with a 16-fold increase in the rate at which the cells were able to take up and degrade the lipoprotein. The LDL binding and degradation processes that developed in normal lymphocytes exhibited the following characteristics; (a) high affinity (saturation was achieved at LDL concentrations below 50 mug protein/ml); (b) specificity (unlabeled LDL was much more effective than human high density lipoprotein or other plasma proteins in competing with 125I-LDL for binding to the LDL receptor); and(c) feedback regulation (the increase in the number of LDL receptors that appeared after incubation of freshly isolated lymphocytes in lipoprotein-deficient medium was prevented by exposure of the cells to either LDL or a mixture of 25-hydroxycholesterol plus cholesterol but not to HDL). Freshly isolated lymphocytes obtaine from three subjects with the homozygous form of familial hypercholesterolemia failed to develop normal amounts of LDL receptor activity when incubated in medium devoid of lipoproteins. The current data indicate: (a) that the LDL receptors that appear on the surface of cholesterol-deprived, normal human lymphocytes are genetically identical to the previously characterized LDL receptors of cultured human fibroblasts and long-term lymphoid cells and (b) that at least one cell type in the human body, the circulating human lymphocyte, has the capacity to produce a high affinity LDL receptor that mediates the cellular uptake and degradation of plasma LDL.     

Time-dependent effect of statins on platelet function in hypercholesterolaemia

BACKGROUND: Reduction of platelet activity induced by statins has been described as a positive effect exerted by such molecules on vascular thrombotic events. However, the relations among cholesterol (LDL-C) reduction, the timing of the antiplatelet effect, the involved mechanisms and the doses of each statin able to reduce platelet function are not actually well known. The aim of our study was to evaluate the impact of simvastatin (20 mg day-1), atorvastatin (10 mg day-1), fluvastatin (40 mg day-1) and pravastatin (40 mg day-1) on platelet function in hypercholesterolaemic subjects with relation to (LDL-C), oxidized-LDL (ox-LDL) and antiport mechanism modifications. MATERIALS AND METHODS: Sixteen subjects were assigned to each treatment (40 males, 24 females, mean age 48.7 +/- 13.4, LDL-C 5.13 +/- 0,23 mmol L-1) and evaluated for platelet surface P-selectin (P-sel), lipid profile, ox-LDL, platelet-associated ox-LDL (Pox-LDL), platelet cholesterol content, antiport mechanisms, and intracellular and systemic NO synthase every 7 days for one month. RESULTS: Our data show a strong relation between enhanced P-sel and Pox-LDL (r = 0.68, P < 0.01). Simvastatin, atorvastatin, fluvastatin and pravastatin reduce platelet activity after 1, 2, 3 and 4 weeks of treatment, respectively (P < 0.001, P < 0.001, P < 0.01, P < 0.05). Pox-LDL are modulated early by simvastatin, atorvastatin and fluvastatin Pox-LDL (r = 0.66, 0.65 and 0.52; P < 0.001, 0.001 and 0.01, respectively) whereas LDL-C and ox-LDL reductions associated to modifications of antiport activity act later. Moreover, they are the most relevant finding in pravastatin-related subjects. CONCLUSIONS: Our data suggest a different impact of several statins on platelet function, which is initially related to interference with Pox-LDL rather than LDL-C reduction.     

Dual effect of lovastatin and simvastatin on LDL-macrophage interaction.

Lovastatin and simvastatin which are very potent cellular cholesterol biosynthesis inhibitors, significantly affect the plasma lipoprotein concentration. After incubation of plasma with 14C-labelled compounds, radioactivity was found in all lipoprotein fractions but mainly (40%) in high density lipoprotein (HDL), and in the lipoprotein-deficient plasma fraction (20-30%). Drug-treated lipoproteins showed reduced electrophoretic mobility on cellulose acetate in comparison with control lipoproteins. The lovastatin-treated low density lipoprotein (LDL) displayed 28% increased fluidity in comparison with control LDL. The immunoreactivity of drug-treated LDL with monoclonal antibody directed towards the LDL receptor binding domains (B1B6) was significantly less than that of control LDL, suggesting reduced binding to the LDL receptor. When drug-treated LDL was incubated with J-774 A.1 macrophage-like cell line, its binding (at 4 degrees C) was 28% less than that of control LDL, whereas a substantial increase in the cellular cholesterol esterification rate (by 83% with lovastatin and by 67% with simvastatin) was noted. Similarly, the degradation of lovastatin and simvastatin-treated LDL by macrophages was 87-89% greater than that of control LDL. The "apparent Vmax" for the macrophage degradation of lovastatin-treated LDL was 70% greater than that for control LDL. Thus, both drugs may have a dual effect on the macrophage uptake of LDL; they may increase the number of LDL receptors on the cell surface, but they may also reduce the affinity of LDL for its receptor, the former being the major effect.(ABSTRACT TRUNCATED AT 250 WORDS)     

Elevated cholesterol and bile acid synthesis in an adult patient with homozygous familial hypercholesterolemia. Reduction by a high glucose diet.

Elevated levels of cholesterol synthesis are reported for several young children with homozygous familial hypercholesterolemia (HFH) and are considered to contribute directly to their hypercholesterolemia. In contrast, increased cholesterol production has not previously been found in adult patients with HFH. Using the fecal steroid balance technique, we studied rates of cholesterol and bile acid synthesis in a 24-yr-old man who had severe hypercholesterolemia typical of HFH and who lacked skin fibroblast low density lipoprotein (LDL) receptor activity. On an average diet (45% carbohydrate, 40% fat, 15% protein) mean +/- SEM cholesterol (24.8 +/- 1.4 mg/kg per d) and bile acid (11.1 +/- 1.6 mg/kg per d) excretion were approximately threefold higher than normal. When an isocaloric high carbohydrate, low fat diet (90.5% glucose oligosaccharides, 1.3% safflower oil, 8.2% crystalline amino acids was substituted, mean cholesterol (13.0 +/- 0.5 mg/kg per d) and bile acid (8.6 +/- 0.4 mg/kg per d) fell markedly. The decline in fecal steroid excretion was accompanied by modest reductions in plasma total and LDL cholesterol concentrations and by a softening of cutaneous xanthomata. Although the patient phenotypically and biochemically resembled the HFH state, his family pedigree was not noteable for hypercholesterolemia. While the patient's father had premature cardiovascular disease, his mother had no evidence of heart disease, had normal plasma total and LDL cholesterol levels, and had normal fibroblast LDL receptor activity. Likewise, the plasma cholesterol levels of three other members of the patient's family were normal. Despite the unusual genotypic background of this individual, however, the fecal balance data shows that elevated cholesterol and bile acid synthesis may occur in adult, as well as juvenile, patients with HFH and may be responsive to dietary control.     

Cost-effectiveness analysis of rosuvastatin versus atorvastatin, simvastatin, and pravastatin from a Canadian health system perspective

OBJECTIVE: The primary objective of this study was to assess the cost-effectiveness of the most commonly prescribed doses of rosuvastatin, atorvastatin, simvastatin, and pravastatin for managing various lipid parameters in patients with hypercholesterolemia over a 1-year time horizon from a Canadian health care perspective. METHODS: Incremental cost-effectiveness ratios (ICERs) were estimated for branded rosuvastatin compared with branded atorvastatin, generic simvastatin, and generic pravastatin in patients with hypercholesterolemia in terms of percent reduction in low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC)/high-density lipoprotein cholesterol (HDL-C) ratio, as well as in TC, HDL-C, triglycerides (TG), apolipoprotein (Apo) B, the ApoB/ApoA-I ratio, and attainment of the Canadian LDL-C goal. The pharmacoeconomic model was constructed for a 1-year time horizon using efficacy data from a randomized, open-label trial including 2268 adults and the wholesale acquisition costs of branded rosuvastatin and atorvastatin and generic simvastatin and pravastatin in British Columbia. RESULTS: The most commonly prescribed doses of each of the 4 statins in British Columbia were as follows: rosuvastatin 10 mg (75.8% of all rosuvastatin doses); atorvastatin 10 and 20 mg (46.4% and 35.3%, respectively, of all atorvastatin doses); simvastatin 20 and 40 mg (42.5% and 31.8%, respectively, of all simvastatin doses); and pravastatin 20 and 40 mg (55.0% and 34.1%, respectively, of all pravastatin doses). Rosuvastatin 10 mg was dominant (ie, was more effective at a lower cost) relative to atorvastatin 10 and 20 mg, simvastatin 20 and 40 mg, and pravastatin 40 mg in terms of reductions in LDL-C, TC/ HDL-C ratio, TC, ApoB, and ApoB/ApoA-I ratio, increases in HDL-C, and attainment of the LDL-C goal. Compared with pravastatin 20 mg, the ICER per percent reduction in LDL-C, TC/HDL-C ratio, TC, TG, ApoB, or ApoB/ApoA-I or increase in HDL-C ranged from $3.89 to $26.07; the value for 1 additional patient achieving the LDL-C goal was $419.75. When the statin doses were aggregated based on the Canadian statin-utilization pattern, rosuvastatin was dominant relative to atorvastatin on all effectiveness measures evaluated. When rosuvastatin was compared with generic simvastatin and pravastatin, the annual costs for 1 additional patient achieving the LDL-C goal were $144.51 and $373.91, respectively. Based on the sensitivity analysis, rosuvastatin was associated with the highest probability of cost-effectiveness compared with the other statins over a broad range of monetary values per unit of clinical effect. CONCLUSION: When percent changes in lipid parameters and rates of LDL-C goal attainment were considered in patients with hypercholesterolemia in British Columbia, rosuvastatin 10 mg was more cost-effective than the most frequently used doses of atorvastatin (10 and 20 mg), generic simvastatin (20 and 40 mg), and generic pravastatin (20 and 40 mg).     

Efficacy, safety and LDL-C goal attainment of ezetimibe 10 mg-simvastatin 20 mg vs. placebo-simvastatin 20 mg in UK-based adults with coronary heart disease and hypercholesterolaemia

It is increasingly accepted that more intensive lipid‐lowering treatment is associated with greater cardiovascular risk reductions in patients with coronary heart disease (CHD), thus providing a rationale for more aggressive LDL‐cholesterol (LDL‐C) targets. Ezetimibe in combination with statin therapy provides an additional approach to lipid management by utilising the additive action of two different mechanisms of LDL‐C reduction. In this multicentre, randomised, double‐blind, placebo‐controlled study, a total of 98 men and 55 women with CHD and primary hypercholesterolaemia, naïve to statin therapy, were randomised to receive treatment for 6 weeks with either ezetimibe 10 mg–simvastatin 20 mg (n = 77) or placebo–simvastatin 20 mg (n = 75). At 6 weeks, ezetimibe 10 mg–simvastatin 20 mg provided a mean additional LDL‐C reduction of 14.6% (95% CI 10.1–19.1) compared with simvastatin monotherapy (p < 0.0001). Moreover, a higher proportion of patients on ezetimibe/simvastatin achieved the National Standard Framework LDL‐C standard (<3.0 mmol/l; 93% vs. 75%, p < 0.001) or the new Joint British Societies (JBS 2) goal of LDL‐C < 2.0 mmol/l (49.3% vs. 11.1%, p < 0.001). On logistic regression analysis, the odds ratio of achieving target LDL‐C with ezetimibe 10 mg–simvastatin 20 mg was 5.1 (95% CI 1.8–15.0) times higher than with simvastatin monotherapy (p = 0.003). Clinical chemistry profiles and proportions of adverse events were similar in both groups at baseline and follow‐up. In conclusion, ezetimibe 10 mg–simvastatin 20 mg is a practical, effective and safe option for the treatment of primary hypercholesterolaemia in CHD patients, and brings more patients to new aggressive cholesterol targets compared with simvastatin 20 mg monotherapy.