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1.
Clin Pharmacol Ther ; 91(1): 109-22, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22130116

ABSTRACT

Cholesteryl ester transfer protein (CETP) inhibition is a promising experimental strategy to raise high-density lipoprotein cholesterol (HDL-C) and reduce cardiovascular risk. This review focuses on the highly selective and potent CE TP inhibitor anacetrapib and discusses the available preclinical and clinical information pertaining to it. We also describe strategies to target HDL-C, discuss the mechanism underlying CETP inhibition and its effects on lipid biology, and give an overview of other CETP inhibitors that are currently in development.


Subject(s)
Anticholesteremic Agents/therapeutic use , Cardiovascular Diseases/drug therapy , Cardiovascular Diseases/metabolism , Cholesterol Ester Transfer Proteins/antagonists & inhibitors , Oxazolidinones/therapeutic use , Risk Reduction Behavior , Animals , Cholesterol Ester Transfer Proteins/physiology , Clinical Trials as Topic/methods , Humans
2.
Int J Clin Pract ; 62(6): 896-904, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18410350

ABSTRACT

INTRODUCTION: Niacin is underutilised because of flushing. Lack of a quantitative tool to assess niacin-induced flushing has precluded the objective evaluation of flushing associated with extended-release (ER) niacin formulations. We developed the Flushing Symptom Questionnaire((c)) (FSQ), a quantitative tool to assess patient-reported flushing, and assessed its ability to characterise ER niacin-induced flushing. METHODS: This study focused on the responses to one question in the FSQ, the Global Flushing Severity Score (GFSS), reported on a 0-10 scale (none = 0, mild = 1-3, moderate = 4-6, severe = 7-9 and extreme = 10) to assess flushing during ER niacin initiation (week 1) and maintenance (weeks 2-8). RESULTS: Flushing severity with ER niacin was greatest during week 1 and remained greater than placebo for the study duration. During weeks 2-8, 40% of patients on ER niacin vs. 8% of those on placebo had > 1 day/week with 'moderate or greater' GFSS. CONCLUSIONS: In conclusion, the GFSS component of the FSQ was a sensitive and responsive quantitative measure of ER niacin-induced flushing that will aid in the objective comparison of novel strategies intended to improve tolerability and adherence to niacin, an agent proven to reduce cardiovascular risk.


Subject(s)
Flushing/chemically induced , Niacin/adverse effects , Vasodilator Agents/adverse effects , Adolescent , Adult , Aged , Delayed-Action Preparations , Female , Humans , Male , Middle Aged , Niacin/administration & dosage , Surveys and Questionnaires , Treatment Outcome , Vasodilator Agents/administration & dosage , Young Adult
3.
Curr Med Res Opin ; 17(1): 43-50, 2001.
Article in English | MEDLINE | ID: mdl-11464446

ABSTRACT

OBJECTIVE: At higher doses, simvastatin has been shown to produce significantly greater increases in high-density lipoprotein (HDL) cholesterol and apolipoprotein (apo) A-I than atorvastatin. To extend and confirm these findings, a 36-week, randomized, double-blind, dose-titration study was performed in 826 hypercholesterolemic patients to compare the effects of simvastatin and atorvastatin on HDL cholesterol, apo A-I, and clinical and laboratory safety. PRIMARY HYPOTHESIS: Simvastatin, across a range of doses, will be more effective than atorvastatin at raising HDL cholesterol and apo A-I levels. METHODS: A total of 826 hypercholesterolemic patients were enrolled in this double-blind, randomized, parallel, 36-week, dose-escalation study. Patients randomized to simvastatin received 40 mg/day for the first 6 weeks, 80 mg/day for the next 6 weeks, and remained on 80 mg/day for the final 24 weeks. Patients randomized to atorvastatin received 20 mg/day for the first 6 weeks, 40 mg/day for the next 6 weeks, and 80 mg/day for the remaining 24 weeks. RESULTS: During the first 12 weeks of the study, simvastatin increased HDL cholesterol and apo A-I more than the comparative doses of atorvastatin, while producing slightly lower reductions in low-density lipoprotein (LDL) cholesterol and triglycerides. At the maximal dose comparison, simvastatin 80 mg and atorvastatin 80 mg, the HDL cholesterol and apo A-I differences favoring simvastatin were larger than at the lower doses. In addition, at the maximal dose comparison, the incidence of drug-related clinical adverse experiences was approximately two-fold higher with atorvastatin 80 mg than with simvastatin 80 mg (23 versus 12%, p < 0.001), due predominantly to a greater incidence of gastrointestinal symptoms with atorvastatin (10 versus 3%, p < 0.001). The incidence of clinically significant alanine aminotransferase elevations was also higher with atorvastatin 80 mg than with simvastatin 80 mg (3.8 versus 0.5%, p < 0.010), especially in women (6.0 versus 0.6%). CONCLUSIONS: At the doses compared in this study, simvastatin led to greater increases in HDL cholesterol and apo A-I levels than atorvastatin. At the maximum dose comparison, there were fewer drug-related gastrointestinal symptoms and clinically significant aminotransferase elevations with simvastatin.


Subject(s)
Anticholesteremic Agents/therapeutic use , Heptanoic Acids/therapeutic use , Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use , Hypercholesterolemia/drug therapy , Lipids/blood , Pyrroles/therapeutic use , Simvastatin/therapeutic use , Adult , Aged , Anticholesteremic Agents/administration & dosage , Anticholesteremic Agents/adverse effects , Apolipoprotein A-I/blood , Atorvastatin , Cholesterol, HDL/blood , Cholesterol, LDL/blood , Double-Blind Method , Female , Heptanoic Acids/administration & dosage , Heptanoic Acids/adverse effects , Humans , Hydroxymethylglutaryl-CoA Reductase Inhibitors/administration & dosage , Hydroxymethylglutaryl-CoA Reductase Inhibitors/adverse effects , Hypercholesterolemia/blood , Male , Middle Aged , Pyrroles/administration & dosage , Pyrroles/adverse effects , Simvastatin/administration & dosage , Simvastatin/adverse effects , Treatment Outcome , United States
5.
Clin Cardiol ; 23(1): 39-46, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10680028

ABSTRACT

BACKGROUND: Elevated levels of low-density lipoprotein (LDL) cholesterol promote the development of atherosclerosis and coronary heart disease. HYPOTHESIS: Simvastatin 80 mg/day will be more effective than simvastatin 40 mg/day at reducing LDL cholesterol and will be well tolerated. METHODS: Two similar, randomized, multicenter, controlled, double-blind, parallel-group, 48-week studies were performed to evaluate the long-term lipid-altering efficacy and safety of simvastatin 80 mg/day in patients with hypercholesterolemia. One study conducted in the US enrolled patients meeting the National Cholesterol Education Program (NCEP) LDL cholesterol criteria for pharmacologic treatment. In the other multinational study, patients with LDL cholesterol levels > or = 4.2 mmol/l were enrolled. At 20 centers in the US and 19 countries world-wide, 1,105 hypercholesterolemic patients, while on a lipid-lowering diet, were randomly assigned at a ratio of 2:3 to receive simvastatin 40 mg (n = 436) or 80 mg (n = 669) once daily for 24 weeks. Those patients completing an initial 24-week base study were enrolled in a 24-week blinded extension. Patients who had started on the 80 mg dose in the base study continued on the same dose in the extension, while those who had started on the 40 mg dose were rerandomized at a 1:1 ratio to simvastatin 40 or 80 mg in the extension. RESULTS: There was a significant advantage in the LDL cholesterol-lowering effect of the 80 mg dose compared with that of the 40 mg dose, which was maintained over the 48 weeks of treatment. The mean percentage reductions (95% confidence intervals) from baseline in LDL cholesterol for the 40 and 80 mg groups were 41% (42, 39) and 47% (48, 46), respectively, for the 24-week base study, and 41% (43, 39) and 46% (47, 45), respectively, after 48 weeks of treatment (p < 0.001 between groups). Larger reductions in total cholesterol and triglycerides were also observed with the 80 mg dose compared with the 40 mg dose at Weeks 24 and 48. Both doses were well tolerated, with close to 95% of patients enrolled completing the entire 48 weeks of treatment. Myopathy (muscle symptoms plus creatine kinase increase > 10 fold upper limit of normal) and clinically significant hepatic transaminase increases (> 3 times the upper limit of normal) occurred infrequently with both doses. There was no significant difference between the groups in the number of patients with such increases, although there were more cases for both with the 80 mg dose. CONCLUSIONS: Compared with the 40 mg dose, simvastatin 80 mg produced greater reductions in LDL cholesterol, total cholesterol, and triglycerides. Both doses were well tolerated.


Subject(s)
Anticholesteremic Agents/therapeutic use , Hypercholesterolemia/drug therapy , Lipids/blood , Simvastatin/therapeutic use , Adult , Aged , Anticholesteremic Agents/administration & dosage , Anticholesteremic Agents/adverse effects , Cholesterol, HDL/blood , Cholesterol, LDL/blood , Cholesterol, VLDL/blood , Dose-Response Relationship, Drug , Double-Blind Method , Female , Humans , Hypercholesterolemia/blood , Male , Middle Aged , Simvastatin/administration & dosage , Simvastatin/adverse effects , Treatment Outcome , Triglycerides/blood
6.
Nutr Metab Cardiovasc Dis ; 10(5): 253-62, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11213534

ABSTRACT

BACKGROUND AND AIM: Clinical data suggesting that larger decreases in low density lipoprotein cholesterol (LDL-C) result in greater reductions in coronary heart disease events have led to the establishment of aggressive LDL-C targets for the treatment of hypercholesterolemia. In view of this, the efficacy and safety of a new maximum dose of simvastatin, 80 mg, were evaluated in 9 studies involving 2819 hypercholesterolemic patients. This report focuses on the combined results from the 4 main or Pivotal studies in which a total of 1936 patients received simvastatin 40 or 80 mg for 36 to 48 weeks. METHODS AND RESULTS: The Pivotal studies had similar randomized, multicenter, controlled, double-blind, parallel-group designs. Their combined results demonstrated a significant advantage in the LDL-C-lowering effect for the 80 mg dose. At week 24, the mean percentage reductions (95% confidence intervals) from baseline in LDL-C for the 40 and 80 mg groups were -39.8% (-40.9, -38.7) and -45.7% (-46.5, -45.0) respectively (p < 0.001, between groups), and larger reductions in total cholesterol and triglycerides were also observed in the 80 mg group. Both doses were well tolerated. No new or unexpected adverse events were observed and the overall clinical event profiles were similar in the two groups. Clinically significant hepatic transaminase increases (> 3 times the upper limit of normal/ULN) and myopathy (muscle symptoms plus creatine kinase increase > 10 times ULN) occurred infrequently with both doses. Simvastatin 80 mg had a comparable efficacy and safety profile in women and men as well as in non-elderly and elderly patients. CONCLUSIONS: Simvastatin 80 mg provides additional LDL-C and triglyceride reductions compared to the 40 mg dose and has an excellent safety and tolerability profile.


Subject(s)
Anticholesteremic Agents/therapeutic use , Cholesterol, LDL/drug effects , Hypercholesterolemia/drug therapy , Simvastatin/therapeutic use , Adolescent , Adult , Aged , Anticholesteremic Agents/adverse effects , Anticholesteremic Agents/pharmacology , Dose-Response Relationship, Drug , Double-Blind Method , Female , Humans , Hypercholesterolemia/blood , Male , Middle Aged , Randomized Controlled Trials as Topic , Safety , Simvastatin/adverse effects , Simvastatin/pharmacology , Treatment Outcome
7.
Am J Cardiol ; 82(3): 311-6, 1998 Aug 01.
Article in English | MEDLINE | ID: mdl-9708659

ABSTRACT

This randomized, multicenter, double-blind parallel-group study was performed to evaluate the lipid-altering efficacy and safety of simvastatin 80 mg/day, a dose twice the current maximum recommended dose. At 20 centers in the United States, 521 male and female hypercholesterolemic patients were randomly assigned in a ratio of 2:3 to receive simvastatin 40 or 80 mg once daily, respectively, for 24 weeks in conjunction with a lipid-lowering diet. Patients met National Cholesterol Education Program (NCEP) low-density lipoprotein (LDL) cholesterol criteria for pharmacologic treatment. The mean percentage reductions (95% confidence intervals) from baseline in LDL cholesterol averaged at weeks 18 and 24 were 38% (-40 to -36) and 46% (-47 to -45) for the 40- and 80-mg groups, respectively (p <0.001 between groups). One third of patients on the 40- and 80-mg doses achieved an LDL cholesterol reduction of 46% and > or = 53%, respectively. Decreases in apolipoprotein B, total cholesterol, and triglycerides were also significantly greater among patients receiving 80 mg/day. Simvastatin was well tolerated in both groups. Two patients (0.6%) in the 80-mg group developed myopathy. Consecutive, clinically significant hepatic transaminase elevations occurred in 3 (1.0%) and 6 (1.9%) patients in the 40- and 80-mg groups, respectively (p= 0.486). In conclusion, simvastatin 80 mg/day provided substantial reductions in LDL cholesterol, allowing most patients to reach their NCEP target levels; it also had an excellent safety and tolerability profile.


Subject(s)
Anticholesteremic Agents/therapeutic use , Hypercholesterolemia/drug therapy , Simvastatin/therapeutic use , Adult , Aged , Anticholesteremic Agents/administration & dosage , Anticholesteremic Agents/adverse effects , Apolipoproteins B/blood , Cholesterol/blood , Cholesterol, HDL/blood , Cholesterol, LDL/blood , Double-Blind Method , Female , Follow-Up Studies , Humans , Hypercholesterolemia/blood , Male , Middle Aged , Safety , Simvastatin/administration & dosage , Simvastatin/adverse effects , Treatment Outcome , Triglycerides/blood , United States
8.
Am J Cardiol ; 79(1): 38-42, 1997 Jan 01.
Article in English | MEDLINE | ID: mdl-9024733

ABSTRACT

The hydroxymethylglutaryl coenzyme A reductase inhibitor simvastatin is the most effective of the currently approved hypolipidemic drugs and has been shown to reduce mortality and coronary morbidity in patients with coronary artery disease. For these patients the United States National Cholesterol Education Program advocates reducing low-density lipoprotein (LDL) cholesterol to <100 mg/dl. However, in some patients this cannot be achieved using monotherapy with simvastatin 40 mg/day, the current maximal recommended dose. To evaluate the effectiveness of extending the dosage range, 156 subjects with LDL cholesterol >160 mg/dl and triglycerides (TG) <350 mg/dl were randomized to simvastatin at doses of 40, 80, and 160 mg/day in a 26 week, double-blind, 3-period, complete block crossover study. Each active treatment period was 6 weeks in duration with intervening 2 week washout periods. Median reductions from baseline in LDL cholesterol were 41%, 47%, and 53% in the 40-, 80-, and 160-mg groups, respectively. The corresponding reductions in plasma TG were 21%, 23%, and 33%. High-density lipoprotein (HDL) cholesterol increased by 6% to 8% in each group. One patient (0.7%) taking 160 mg developed myopathy; 1 patient (0.7%) taking 80 mg, and 3 (2.1%) taking 160 mg had transaminase elevations > 3 times the upper limit of normal. No new or unexpected adverse effects were observed. We conclude that simvastatin at doses of 80 and 160 mg/day provides additional efficacy with a low short-term incidence of adverse effects; our results support the continued investigation of simvastatin at these doses.


Subject(s)
Anticholesteremic Agents/administration & dosage , Lovastatin/analogs & derivatives , Adult , Aged , Anticholesteremic Agents/adverse effects , Cross-Over Studies , Double-Blind Method , Drug Tolerance , Female , Humans , Lovastatin/administration & dosage , Lovastatin/adverse effects , Male , Middle Aged , Simvastatin
9.
Atherosclerosis ; 135(2): 249-56, 1997 Dec.
Article in English | MEDLINE | ID: mdl-9430375

ABSTRACT

Patients with homozygous familial hypercholesterolaemia (HFH) have abnormalities in both low-density lipoprotein (LDL) receptor alleles, resulting in severe hypercholesterolaemia and premature coronary heart disease. Limited treatment options are available and the response to drug therapy has been poor. In the present paper, we have evaluated the efficacy and safety of simvastatin at doses beyond the current maximal dose of 40 mg/day in patients with HFH. After a 4 week placebo diet run-in period, 12 patients with well-characterized HFH were randomized to simvastatin 80 mg/day administered in three divided doses (n = 8; group 1) or 40 mg once daily (n = 4; group 2). After 9 weeks, the dose in group 1 was increased to 160 mg/day while the dose in group 2 was kept at 40 mg/day, but with the drug given in three divided doses and treatment continued for an additional 9 weeks. All 12 patients completed the study and there were no serious or unexpected adverse effects. LDL-cholesterol concentrations fell by 14% at the 40 mg/day dose, but were reduced further at the higher doses (25% at the 80 mg/day and by 31% at the 160 mg/day dosage, P < 0.0001). Excretion of urinary mevalonic acid, as an index of in vivo cholesterol biosynthesis, was reduced but did not correlate with reduction in LDL-cholesterol in the individual patients. The magnitude of response to therapy was not predicted by the LDL-receptor gene defect as patients with the same LDL-receptor mutations responded differently to the same dose of simvastatin therapy. The ability of expanded doses of simvastatin (80 or 160 mg/day) to reduce LDL-cholesterol levels in patients with HFH, even if receptor negative, suggests that at these doses, the drug reduces LDL production. Simvastatin therapy, at doses of 80 or 160 mg/day, should therefore be considered in all patients with HFH, either as an adjunct to apheresis, or as monotherapy for those patients who do not have access to apheresis or other such treatment modalities.


Subject(s)
Homozygote , Hyperlipoproteinemia Type II/drug therapy , Hyperlipoproteinemia Type II/genetics , Simvastatin/administration & dosage , Adolescent , Adult , Anticholesteremic Agents/administration & dosage , Apolipoproteins B/biosynthesis , Cholesterol, LDL/antagonists & inhibitors , Cholesterol, LDL/biosynthesis , Dose-Response Relationship, Drug , Double-Blind Method , Drug Administration Schedule , Female , Humans , Hyperlipoproteinemia Type II/blood , Liver/drug effects , Liver/metabolism , Male
10.
Atherosclerosis ; 116(2): 153-62, 1995 Aug.
Article in English | MEDLINE | ID: mdl-7575771

ABSTRACT

The long-term efficacy and tolerability of simvastatin, a 3-hydroxy-3-methylglutaryl-co-enzyme A (HMG-CoA) reductase inhibitor, was assessed during a 24-month follow-up period in 168 elderly hypercholesterolemic patients. After completing a 4 week double blind dose ranging study with simvastatin, 47 males and 122 females over 62 years of age with type II hyperlipidemia, a total cholesterol level above 6.5 mmol/l and clinically manifest cardiovascular disease were included in this extended study. A total of 159 patients completed the 12-month follow-up period and 141 patients were monitored over the full 24 months. All patients were started on 10 mg simvastatin once daily and the dosage was increased until the target levels of low density lipoprotein (LDL) cholesterol between 2.3 mmol/l (90 mg/dl) and 3.6 mmol/l (140 mg/dl) were reached. Fifty percent of patients reached the targeted LDL cholesterol goal of < 3.6 mmol/l (140 mg/dl) during the study. At study completion, 65 patients (39%) were taking 40 mg simvastatin per day, 56 patients (33%) 20 mg, 42 patients (25%) 10 mg and 5 patients (3%) only used 5 mg per day. Sixteen patients (9%) received concomitant lipid lowering therapy. Over 2 years, the mean decrease in LDL cholesterol ranged from 36% to 38%, the median decrease in triglycerides was 12% to 19% and the mean increase in high density lipoprotein (HDL) cholesterol ranged from 9% to 10%, respectively. Seven patients discontinued simvastatin because of adverse clinical or laboratory events, but only in two (1.1%) was this considered to be drug-related. Side-effects were mild and most frequently gastrointestinal in nature. Mean changes in asparate aminotransferase (AST) were not significantly different from zero and mean changes in alanine aminotransferase (ALT) and creatine phosphokinase (CPK) showed a small increase. We conclude that simvastatin is an efficacious and well-tolerated treatment for hypercholesterolemia in elderly individuals for extended periods.


Subject(s)
Anticholesteremic Agents/therapeutic use , Hydroxymethylglutaryl-CoA Reductase Inhibitors , Hypercholesterolemia/drug therapy , Lovastatin/analogs & derivatives , Aged , Aged, 80 and over , Anticholesteremic Agents/adverse effects , Cholesterol/blood , Double-Blind Method , Female , Follow-Up Studies , Humans , Hypercholesterolemia/blood , Hypercholesterolemia/complications , Lipids/blood , Lovastatin/adverse effects , Lovastatin/therapeutic use , Male , Middle Aged , Simvastatin
11.
Arch Intern Med ; 154(14): 1586-95, 1994 Jul 25.
Article in English | MEDLINE | ID: mdl-8031206

ABSTRACT

BACKGROUND: Niacin and lovastatin are both effective drugs for the treatment of hypercholesterolemia and are among the drugs of first choice recommended by the adult treatment panel. To date, however, no studies have directly compared the lipoprotein-modifying effects and safety of lovastatin and niacin across their usual dosage range in patients with primary hypercholesterolemia. METHODS: The efficacy and safety of lovastatin and niacin were compared in a controlled, randomized, open-label study of 26 weeks' duration that was conducted at five lipid clinics. One hundred thirty-six patients with primary hypercholesterolemia participated in the study. Entry criteria were a low-density lipoprotein (LDL) cholesterol level greater than 4.37 mmol/L (160 mg/dL) with coronary heart disease and/or more than two coronary heart disease risk factors or an LDL cholesterol level greater than 5.19 mmol/L (190 mg/dL) in patients without coronary heart disease or less than two coronary heart disease risk factors. The study consisted of a 4-week diet run-in period after which eligible patients were randomly assigned to receive treatment with either lovastatin (20 mg/d) or niacin (1.5 g/d) for 10 weeks. On the basis of the LDL cholesterol response and patient tolerance, the doses were sequentially increased to 40 and 80 mg/d of lovastatin or 3 and 4.5 g/d of niacin after 10 and 18 weeks of treatment, respectively. RESULTS: In the two patient groups, 66% of patients treated with lovastatin and 54% of patients treated with niacin underwent full dosage titration. At all time points, lovastatin was significantly (P < .01) more effective than niacin in reducing LDL cholesterol levels (26% vs 5% at week 10, 28% vs 16% at week 18, and 32% vs 23% at week 26), whereas niacin was more effective (P < .01) in increasing high-density lipoprotein cholesterol levels (6% vs 20% at week 10, 8% vs 29% at week 18, and 7% vs 33% at week 26). Niacin reduced Lp(a) lipoprotein levels by 35% at week 26, whereas lovastatin had no effect. Cutaneous flushing was the most common side effect during treatment with niacin. CONCLUSIONS: Lovastatin and niacin both exerted favorable dose-dependent changes on the concentrations of plasma lipids and lipoproteins. Lovastatin was more effective in reducing LDL cholesterol concentrations, whereas niacin was more effective in increasing high-density lipoprotein cholesterol concentrations and reducing the Lp(a) lipoprotein level. Lovastatin was better tolerated than niacin, in large part because of the common cutaneous side effects of niacin.


Subject(s)
Hypercholesterolemia/drug therapy , Lovastatin/therapeutic use , Niacin/therapeutic use , Adult , Aged , Female , Humans , Hypercholesterolemia/blood , Lipids/blood , Lipoproteins/blood , Lipoproteins/drug effects , Lovastatin/adverse effects , Male , Middle Aged , Niacin/adverse effects
12.
Pharm Res ; 10(11): 1683-7, 1993 Nov.
Article in English | MEDLINE | ID: mdl-8290485

ABSTRACT

Seven sustained/controlled-release dosage forms were designed for gastrointestinal delivery of lovastatin or simvastatin, two potent HMG-CoA reductase inhibitors for the treatment of hypercholesterolemia. The in vivo performance of these formulations was evaluated in dogs and healthy volunteers in terms of the cholesterol lowering efficacy and/or systemic concentrations of HMG-CoA reductase inhibitors. Results from the present and previous studies suggest that, through the controlled release of HMG-CoA reductase inhibitors, sustained lower plasma concentrations of HMG-CoA reductase inhibitors may result in an equal or better therapeutic efficacy.


Subject(s)
Hydroxymethylglutaryl-CoA Reductase Inhibitors , Lovastatin/analogs & derivatives , Lovastatin/administration & dosage , Adult , Animals , Delayed-Action Preparations , Dogs , Double-Blind Method , Humans , Lovastatin/pharmacokinetics , Male , Simvastatin
14.
Biochim Biophys Acta ; 917(2): 324-32, 1987 Feb 14.
Article in English | MEDLINE | ID: mdl-3026486

ABSTRACT

We have used a preparation of rat liver plasma membranes to study the binding of rat apolipoprotein E-deficient HDL to rat liver. The membranes were found to bind HDL by a saturable process that was competed for by excess unlabeled HDL. The binding was temperature-dependent and was 85% receptor-mediated when incubated at 4, 22 and 37 degrees C. The affinity of the binding site for the HDL was consistent at all temperatures, while the maximum binding capacity increased at higher temperatures. The specific binding of HDL to the membranes did not require calcium and was independent of the concentration of NaCl in the media. The effect of varying the pH of the media on HDL binding was small, being 30% higher at pH 6.5 than at pH 9.0. Both rat HDL and human HDL3 were found to compete for the binding of rat HDL to the membranes, whereas rat VLDL remnants and human LDL did not compete. At 4 degrees C, complexes of dimyristoylphosphatidylcholine (DMPC) and apolipoproteins A-I, A-IV and the C apolipoproteins, but not apolipoprotein E, competed for HDL binding to the membranes. At 22 and 37 degrees C, all DMPC-apolipoprotein complexes competed to a similar extent, DMPC vesicles that contained no protein did not compete for the binding of HDL. These results suggest that the rat liver possesses a specific receptor for apolipoprotein E-deficient HDL that recognizes apolipoproteins A-I, A-IV and the C apolipoproteins as ligands.


Subject(s)
Carrier Proteins , Lipoproteins, HDL/metabolism , Liver/metabolism , RNA-Binding Proteins , Receptors, Cell Surface/metabolism , Receptors, Lipoprotein , Animals , Apolipoproteins E , Binding, Competitive , Cell Membrane/metabolism , Humans , In Vitro Techniques , Male , Rats , Rats, Inbred Strains , Receptors, Cell Surface/drug effects , Temperature , Time Factors
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