- Email: [email protected]
2.P.10 Effects of erythromycin on plasma fluvastatin levels: A pharmacokinetic study
Tuesday 7 October Lipid-lowering
118
antibody for detection of lipoproteins after electrotransfer, we have routinely detected up to five species of y-LpE in human plasma, ranging from 9.5 to 16.5 nm in mean particle diameter. The majority of y-migrating apoE, representing less than 5% of total plasma apoE, was associated with y2-LpE having a diameter of 13.0 mu. Neither the amount of y-LpE apoE nor the number of y-LpE species was different in serum v plasma or was affected by the presence of agents able to inhibit protein dimerization during plasma preparation. Incubation of plasma at 37°C (90 min) caused a significant decrease in plasma y-LpE (>50%), which was not dependent on LCAT or CETP activity. Incubation of plasma with cultured fibroblasts (37°C 1 min) caused a significant increase (48 f 14%. mean f SD) in plasma y-LpE @ < 0.05). Storage at -70°C of hypertriglyceridemic but not normolipidemic plasma resulted in an increase in y-LpE. Freezing of postprandial plasma samples, containing increased amounts of triglyceride-rich lipoproteins rich in apoE, also resulted in an increase in y-LpE. Incubation of VLDL (d < 1.006 g/ml) with lipase in vitro caused the production of y-LpE-like particles. These results demonstrate that: 1) different-sized y-LpE particles exist in human plasma; 2) decrease in plasma y-LpE concentration due to incubation at 37°C is not due to LCAT or CETP activity and is reversed by the presence of cells, and 3) y-LpE can be produced in vitro from plasma VLDL.
El2.P.8 M.,
Mutations of the branchpoint concensus sequence of intron 4 of lecithin: Cholesterol acyltransferase (LCAT) gene PH. Pritchard.
Vniversit)
of British
Columbia,
Vancouvtx
Canada
We have previously studied a single nucleotide substitution (T-+C) in a branchpoint region of intron 4 of LCAT in a family with fish-eye disease (FED) which causes a null allele as the result of complete intron retention. In order to further study the functional significance of the intron branchpoint sequence, two new mutations, intron 4 MUT-1 (T-+G) and MUT-2 (T-+A), were introduced into the same site in which the natural mutation occurs, and then cloned into the mammalian vector pNUT. After the pNUT-LCAT minigenes were stably transfected into BHK cells, the activity and concentration of LCAT in the culture medium were determined. The specific activity for LCAT cDNA and the intron 4 wild type (2.34 f 0.68 vs. 2.23 f 1.21 nmol/h/wg) was nearly the same. However, no LCAT activity and protein was detected for and the natural intron 4 mutation. RT-PCR the imron 4 MUT-1 and MUT-2, revealed that LCAT expression was evident in LCAT cDNA, intron 4 wild type, and the intron 4 mutants. However, the sizes of these RT-PCR products for LCAT cDNA, the intron 4 wild type and the mutants are different. The difference between these fragments was 83 bp in length, indicating that the intronic sequence was retained. Subsequent sequence analysis of the RT-PCR products demonstrated that the unspliced intronic sequences contained the desired mutations. In conclusion, the loss of the T, two bases upstream of the internal adenosine residue in the putative branchpoint consensus sequence of the intron 4 of LCAT gene, disrupts the process of pre-mRNA splicing and results in the intron retention.
Ll2 P
1997: Posters drugs
I2
Expression of CETP mRNA by stromal vascular cells of human ndipose tissue T. Radeau, M. Robb, M. McDonnel, R. McPherson. Vniversity of Ottawa P.8
Heart
Institute,
Ottawa,
Canada
CETP is highly expressed in human adipose tissue and its expression may be modulated by fat cell size. Stromal vascular fraction of adipose tissue is composed of various cell types including immature adipocytes, pre-adipocytes, macrophages and endothelial cells. In this study, the relative expression of CETP mRNA was first investigated in mature fat cells (MFC) and stromalvascular cells (SVC). By Northern blot analysis, CETP: 18 S RNA ratio was significantly higher in SVC as compared to MFC (2.18 f 0.21 vs 1.13 & 0.18, 1’ < 0.03, N = 4) whereas lipoprotein lipase/ll S RNA ratio was significantly lower (3.6 f 0.57 vs 14.1 & 2.8, P < 0.03). Pre-adipocytes were further purified from SVC by adherence on plastic and mRNA expression determined by RT-PCR. When normalized to fi actin, CETP mRNA expression in pre-adipocytes was only 20% of that found in SVC. Moreover, the presence of a significant number of monocytes/macrophages was excluded since CD16 mRNA, a marker of these cells, was not found in MFC, SVC or pre-adipocytes. We also demonstrated that a human endothelial cell line does not (express CETP mRNA. These data suggest that a major part of CETP mRNA ir human adipose tissue is produced by SVC, possibly by immature or very small fat cells.
cl2 P
9
Reduced phwma HDL-cholesterol levels in visceral obesity: Contribution of the CETP gene TaqIB polymorphism
M.C. Vohl, B. Lamarche, G. Leroux, D. Prud’homme, C. Bouchard, A. Nadeau, J.P. Desprt?s. Lipid Research CenteK Diabetes Research LABSAP, Lava1 University Ste-Fey, QuPbec. Canada
Unit and
The aim of the present study was to examine whether the TaqIB polymorphism of the CE.TP gene influence HDL-cholesterol levels in visceral obesity. A total of 135 sedentary men: 1) 47 BlBl homozygotes (HMZ) for the presence of the restriction site, 2) 54 BlB2 heterozygotes (HTZ) and 3) 34 B2B2 HMZ participated in this study. The three groups were similar for age, BMI, and visceral adipose tissue (VAT) accumulation assessed by computed tomography. However B2B2 men had significantly higher HDL and HDLs-chol levels than BlBl HMZ (p < 0.05). In order to determine the source of variation of plasma HDL-chol levels, the three genotypic groups were divided into low vs high (< or > 130 cm2) VAT accumulation. The amount of VAT explained 7.6% and 9.4% of he variation in plasma HDL and HDLz-chol levels (p < 0.001). No significant effect of the genotype was observed on HDL-chol levels when VAT accumulation was taken into account. The CETP-TaqIB genotype explained 4.5% of the variation in plasma HDLZ-chol levels (p < 0.05). Essentially similar results were obtained when subjects were divided on the basis of the median value of fasting insulin levels, the CETP-TaqIB genotype explaining 9.3% (p < 0.01) of the variation in plasma HDLZ-chol levels. These results suggest that the CETP-TaqIB polymorphism influences the magnitude of the decrease in plasma HDL-chol levels observed in visceral obesity.
7 Age-related decline in plasma CETP and CETP mRNA expression in human adipose tissue
T. Radeau, M. Robb, P. Lau, J. Borthwick, Ottawa Heart Institute, Ottawa, Canada
R. McPherson.
Vniversity
of
LIPID-LOWERING
Adipose tissue is an important site of CETP synthesis. However, it is not known to what extend adipose tissue CETP contributes to plasma pool of CETP in man Aging is often associated with changes in adipose tissue composition and function. We have determined adipose tissue CETP mRNA concentration by RNase protection assay and plasma levels of CETP by radio-immunoassay as well as plasma lipoproteins in 12 middle aged and elderly subjects with stable coronary heart disease at the time of coronary artery bypass surgery. Plasma concentrations of CETP were highly correlated with pericardial adipose tissue CETP mRNA abundance (R = 0.89, P < 0.002). CETP mRNA concentrations in adipose tissue were inversely related to age (R = -0.72, P < 0.03) as were plasma concentrations of CETP (R = -0.69, P < 0.012). These relationships were independent of plasma lipids, lipoproteins and body mass index. However, adipocyte size, estimated by adipose tissue triglyceride/mg soluble protein were related to CETP mRNA levels (R = -0.76, P < 0.02). There was also a trend for increased adipocyte size with aging. The age-related decline in plasma concentrations of CETP can be explained in part by a decrease in adipose tissue CETP gene expression.
11th International
Symposium
II2.P.10
DRUGS
Effects of erythromycin on plasma fluvastatin levels: A pharmacokinetic study
J. Aberg U. Eriksson, G. Fager. Clinical Pharmacology, and Development, Astra Hiissle AB, Miilndal, Sweden
Introdu&ion:
Clinical
Research
Fluvastatin (F) is a new hydroxy-methylglutaryl coenzyme A reductase inhibitor. At daily doses of 20 to 80 mg it provides marked reductions of LDL cholesterol similar to other drugs of this class. F is predominantly eliminated by hepatic metabolism and it is therefore important to investigate the potential interaction with other drugs eliminated by hepatic metabolism. Erythromycin (E) is cleared by the liver and a suitable model for cytochrome P450 3A depending drugs. Aim: To study the pharmacokinetics of steady state plasma concentrations of F following concurrent administration of a single dose of E. Study Design: The study was an open, randomized, two-way, cross-over design. Twenty-four healthy male subjects (age 21-34 years) participated. Subjects were given F capsules 40 mg o.d. for 12 days. On day 6 and 12 the subjects were randomly given E tablets 500 mg as a single dose or no E. Blood for F plasma assay was frequently drawn on days 6 and 12.
on Atheroscleroris,
Paris,
October
1997
Tuesday 7 October Lipid-lowering
Pharmacokinetic Calculations: The plasma F data for each dosing interval were treated as single dose data because the concentrations declined to below measurable levels within the dosing interval. The area under the plasma concentration-time curve (AUC) was calculated using the linear trapezoidal rule up to the last measurable level and extrapolated to infinity. The maximum plasma concentration (Cmax) was the highest plasma concentration observed and the time to maximum plasma concentration (tmax) was the time for that measurement. Results: There was no pharmacokinetic interaction between F and E indicated by the similarities of the plasma F profiles. There were no differences in the AUC, Cmax or tmax between the different treatment regimens. Mean AUC f SD for F and F + E was 663 f 329 and 781 Z!Y 345 nmol x h/L, respectively. Conclusion: There was no significant influence from administration of erythromycin on fluvastatin steady state pharmacokinetics. This may suggest that cytochorome P450 3A is not a major route for fluvastatin metabolism.
I2.P
11
Effects of atorvastatin on intracelhdar levels and stability of apolipoprotein B and HMG-CoA reductase in Hep 62 cells
K. Adeli, T. Romain, A. Mohammadi, R.S. Newton’, R. Cheung, J. Macri. Department of Biochemistry, University of Windsor; Windsor, Ontario, Canada; ‘Parke-Davis Pharmaceutical Research Division, Ann Arbor; MI, USA
1997: Posters drugs
119
Therefore HMG-CoA reductase inhibitors halted AP surface coverage and intimal thickening by MO infiltration. Selective statins can indeed modulate AP growth and affect the evolution of atherosclerosis. Work supported by FIS 95-0917, SAL 9410712, Parke-Davis, and FIC-Catalana Occidente.
2 P. 13 El
Effect of lovastatin in hyperlipoproteinaemic
1.2. AndielkovZ, D.D. AndjelkoviC, Department cfPhysiology, Medical
2.2. Kojid, D.M. Faculty, Belgrade
patients
Djurie, M.M. Rosie. Serbia, Yugoslavia
Lovastatin is specific competitive inhibitor of hydroxymethyl.glutaryl CoA reductase, the key enzyme in the process of cholesterol synthesis in hepatocytes. Concentrations of cholesterol, triglycerides, HDL-, LDL-cholesterol, apoproteins A, A-I and B and transaminases, were determinated in serum of patients, before and after therapy. Therapy with lovastatin (20 mg/day) was performed during at lealit a month with simultaneous application of diet on adult male and female population (52-76 years) with confirmed hyperlipoproteinaemia type II a and II b. The research provide that lovastatin significantly reduces the values of total cholesterol (7.41 f 0.17 mmol/l vs. 4.99 f 0.35 mmolll), LDL-cholesterol (5.44 f 0.21 mmolil vs. 3.22 f 0.4 mmol/l), apoprotein B (1.97 f 0.19 mmol/l vs. 1.35 f 0.20 mmol/l) and triglycerides (2.21 f 0.21 vs. I.64 & 0.24 mmol/I) while values of HDL-cholesterol, apoproteins A and A-I transaminases weren’t significantly changed (p > 0.05).
We investigated the effect of atorvastatin, a potent HMG-CoA reductase inhibitor, on expression of apolipoprotein B (apoB) and HMG-CoA reductase in HepG2 cells. Cells were pre-treated with atorvastatin (0.1-10 @M) for 18 h, pulsed with [35S] methionine, and chased for various time periods. In some experiments cells were permeabilized with digitonin (50 &ml, 10 min) before the chase. The accumulation and degradation of apoB and HMG-CoA reductase were monitored over 2 h. Atorvastatin did not influence the synthesis of apoB, but reduced the extracellular secretion of apoB. In addition atorvastatin stimulated the expression of HMG-CoA reductase. Atorvastatin had a significant stimulatory effect on HMG-CoA reductase protein levels (% increase over control: atorvastatin 30.6 f 8.9%; n = 4). ApoB stability was decreased with atorvastatin at 10 WM (% apoB remaining: control 36.45 f 1.45; atorvastatin 16.4 i 5.1; n = 3) (atorvastatin as a percentage of control: 44.9%). The stability of HMG-CoA reductase was not influenced by atorvastatin. Atorvastatin reduced the intracellular levels of cholesterol (1.9 fold) and cholesterol ester (4.3 fold) in HepG2 cells but not that of triglycerides, suggesting that the effects on apoB may be mediated through changes in intracellular levels of cholesterol and/or cholesterol ester. Overall, the data suggest that atorvastatin reduced the secretion of apoB by enhancing the degradation of the protein. Atorvastatin had an inhibitory effect on apoB and an inductive effect on intracellular levels of HMG-CoA reductase. The low inductive effect of atorvastatin on HMG-CoA reductase protein may contribute to the higher hypolipidemic efficacy of this drug.
We evaluated the safety profile of atorvastatin, a new HMG-CoA reductase inhibitor (statin), in patients with lipid disorders. In an integrated database of 21 completed studies (2502 atorvastatin-treated patients), 99% df patients received atorvastatin 10 mg through 80 mg/day. atorvastatin was well tolerated with less than 28% withdrawing due to adverse events (AE) considered associated with drug use. The AE profile for atorvastatin was similar to of other statins testeti; 20% of patients in both groups experienced drug associated AEs. The most common AEs were constipation, flatulence, dyspepsia, and abdominal pain. Approximately 5% of atorvastatin-treated patients had serious AEs, with only 2 events considered possibly related to treatment. Including data from ongoing trials (for a total of 4271 atorvastatin-treated patients), 30 (0.7%) patients experienced confirmed alanine aminotmnsferase levels of >3 times the upper limit of normal. The majority of elevations occurred within 16 weeks of treatment initiation. No patient had a conclusive characterization of drug inducesi myopathy. In conclusion, the safety profile of atorvastatin was the same as other marketed statins.
2 P 12 LA
rl
inhibitors of hydroxymethyl glutaryl-CoA reductase as modulators of intimal thickening in diet-induced atherosclerosis
J. AlMn L. Badimon. Barcelona, Spain
Cardiovascular
Research
Center,
15
D.M.
Black, Division
J.W. Nawrocki. Parke-Davis of Warner-Lambert Company,
Ann Arbor,
‘Iwo-year comparison of safety and efficacy of atorvastatin and lovastatin
R.G. Bakker-Arkema, L. Shurzinske, M. Davidson, J. McKenney, E. Stein, H. Schrott, D.M. Black. Parke-Davis Pharmaceutical Research, Division of Warner Lambert Company, Ann Arbor; Michigan, USA
Inhibitors of HMG-CoA reductase are used as cholesterol lowering drugs, and some of them have showed to decrease cardiovascular morbidity and mortality, Their mechanism might be related to the inhibition of atherosclerotic plaque (AP) growth which in turn leads to ischemic episodies. We have studied the effect of Atorvastatin (A) and Simvastatin (S) on AP composition and thickness in rabbits fed hyperlipemic diet (0.5% cholesterol, 15% coconut oil). A (2.5 mg/kg/day, n = 5), S (2.5 mg/kglday, n = 5), or placebo (n = 6) were orally administered during 60 days. Cholesterol levels were significantly reduced by both drugs (A 20%, S 30%) and mural thrombosis (platelet deposition on injured vessel wall at arterial flow conditions) was more effectively reduced by A than by S. At sacrifice, aortas were removed, tixed, OTC included, and sectioned. Sections were stained with Mason’s technique and intimal thickness measured by computer assisted microscopy; immunofluorescence was used for macropbage (RAM II, Dako) smooth muscle cells @-a&in, Dako) and fibrinogen (Dako) localization; and, northern blots were run to assay MCPexpression. Both statins inhibit progression of intimal thickening by 30% and 60% [for A and S (p < 0.05), respectively). Plaques were heavenly infiltrated with MO and Fg irrespectively of treatment, while SMC were scattered within the thickened intimas. MCP was expressed similarly in the three groups. Symposium
An overview of the clinical safety profile of atorvastatin a new, more effective HMG-CoA reductase inhibitor
R.G. Bakker..Arkema Pharmaceutiz&ch, Michigan, USA
2.P
CSIC-HSCSP-VAB,
I1 th International
2 P 14 lxl
In this 2-year study, 787 patients with hypercholesterolemia received either atorvastatin 10 mg to 80 mg/day (623 patients) or lovastatin 20 mg to 80 mg/day (164 patients). Patients were median age of 59 years, Fredrickson Type IIa or IIb. Patients started on the lowest dose and increased their dose until they met their National Cholesterol Education Panel (NCEP) LDL-C goal. At the end of 2 years, 88% of patients on atorvastatin (63% on 10 mg/day) and 74% on lovastatin (39% on 20 mg/day) met their NCEP goal. Atorvastatin reduced LDL-C by 39% compared to 32% by lovastatin (p < 0.01). The safety profile was similar between the 2 compounds. Three patients (0.5%) treated with atorvazjtatin and 4 patients (2.4%) treated with lovastatin had a confirmed alanine aminotransferase value >3 times the upper limit of normal (x ULN). No atorvastatin treated patients had a confirmed CPK elevation > 10 x ULN. Atorvastatin enables more patients to reach NCEP goals while maintaining a safety profile comparable to lovastatin.
on Atherosclerosis,
Paris,
October
1997
118
antibody for detection of lipoproteins after electrotransfer, we have routinely detected up to five species of y-LpE in human plasma, ranging from 9.5 to 16.5 nm in mean particle diameter. The majority of y-migrating apoE, representing less than 5% of total plasma apoE, was associated with y2-LpE having a diameter of 13.0 mu. Neither the amount of y-LpE apoE nor the number of y-LpE species was different in serum v plasma or was affected by the presence of agents able to inhibit protein dimerization during plasma preparation. Incubation of plasma at 37°C (90 min) caused a significant decrease in plasma y-LpE (>50%), which was not dependent on LCAT or CETP activity. Incubation of plasma with cultured fibroblasts (37°C 1 min) caused a significant increase (48 f 14%. mean f SD) in plasma y-LpE @ < 0.05). Storage at -70°C of hypertriglyceridemic but not normolipidemic plasma resulted in an increase in y-LpE. Freezing of postprandial plasma samples, containing increased amounts of triglyceride-rich lipoproteins rich in apoE, also resulted in an increase in y-LpE. Incubation of VLDL (d < 1.006 g/ml) with lipase in vitro caused the production of y-LpE-like particles. These results demonstrate that: 1) different-sized y-LpE particles exist in human plasma; 2) decrease in plasma y-LpE concentration due to incubation at 37°C is not due to LCAT or CETP activity and is reversed by the presence of cells, and 3) y-LpE can be produced in vitro from plasma VLDL.
El2.P.8 M.,
Mutations of the branchpoint concensus sequence of intron 4 of lecithin: Cholesterol acyltransferase (LCAT) gene PH. Pritchard.
Vniversit)
of British
Columbia,
Vancouvtx
Canada
We have previously studied a single nucleotide substitution (T-+C) in a branchpoint region of intron 4 of LCAT in a family with fish-eye disease (FED) which causes a null allele as the result of complete intron retention. In order to further study the functional significance of the intron branchpoint sequence, two new mutations, intron 4 MUT-1 (T-+G) and MUT-2 (T-+A), were introduced into the same site in which the natural mutation occurs, and then cloned into the mammalian vector pNUT. After the pNUT-LCAT minigenes were stably transfected into BHK cells, the activity and concentration of LCAT in the culture medium were determined. The specific activity for LCAT cDNA and the intron 4 wild type (2.34 f 0.68 vs. 2.23 f 1.21 nmol/h/wg) was nearly the same. However, no LCAT activity and protein was detected for and the natural intron 4 mutation. RT-PCR the imron 4 MUT-1 and MUT-2, revealed that LCAT expression was evident in LCAT cDNA, intron 4 wild type, and the intron 4 mutants. However, the sizes of these RT-PCR products for LCAT cDNA, the intron 4 wild type and the mutants are different. The difference between these fragments was 83 bp in length, indicating that the intronic sequence was retained. Subsequent sequence analysis of the RT-PCR products demonstrated that the unspliced intronic sequences contained the desired mutations. In conclusion, the loss of the T, two bases upstream of the internal adenosine residue in the putative branchpoint consensus sequence of the intron 4 of LCAT gene, disrupts the process of pre-mRNA splicing and results in the intron retention.
Ll2 P
1997: Posters drugs
I2
Expression of CETP mRNA by stromal vascular cells of human ndipose tissue T. Radeau, M. Robb, M. McDonnel, R. McPherson. Vniversity of Ottawa P.8
Heart
Institute,
Ottawa,
Canada
CETP is highly expressed in human adipose tissue and its expression may be modulated by fat cell size. Stromal vascular fraction of adipose tissue is composed of various cell types including immature adipocytes, pre-adipocytes, macrophages and endothelial cells. In this study, the relative expression of CETP mRNA was first investigated in mature fat cells (MFC) and stromalvascular cells (SVC). By Northern blot analysis, CETP: 18 S RNA ratio was significantly higher in SVC as compared to MFC (2.18 f 0.21 vs 1.13 & 0.18, 1’ < 0.03, N = 4) whereas lipoprotein lipase/ll S RNA ratio was significantly lower (3.6 f 0.57 vs 14.1 & 2.8, P < 0.03). Pre-adipocytes were further purified from SVC by adherence on plastic and mRNA expression determined by RT-PCR. When normalized to fi actin, CETP mRNA expression in pre-adipocytes was only 20% of that found in SVC. Moreover, the presence of a significant number of monocytes/macrophages was excluded since CD16 mRNA, a marker of these cells, was not found in MFC, SVC or pre-adipocytes. We also demonstrated that a human endothelial cell line does not (express CETP mRNA. These data suggest that a major part of CETP mRNA ir human adipose tissue is produced by SVC, possibly by immature or very small fat cells.
cl2 P
9
Reduced phwma HDL-cholesterol levels in visceral obesity: Contribution of the CETP gene TaqIB polymorphism
M.C. Vohl, B. Lamarche, G. Leroux, D. Prud’homme, C. Bouchard, A. Nadeau, J.P. Desprt?s. Lipid Research CenteK Diabetes Research LABSAP, Lava1 University Ste-Fey, QuPbec. Canada
Unit and
The aim of the present study was to examine whether the TaqIB polymorphism of the CE.TP gene influence HDL-cholesterol levels in visceral obesity. A total of 135 sedentary men: 1) 47 BlBl homozygotes (HMZ) for the presence of the restriction site, 2) 54 BlB2 heterozygotes (HTZ) and 3) 34 B2B2 HMZ participated in this study. The three groups were similar for age, BMI, and visceral adipose tissue (VAT) accumulation assessed by computed tomography. However B2B2 men had significantly higher HDL and HDLs-chol levels than BlBl HMZ (p < 0.05). In order to determine the source of variation of plasma HDL-chol levels, the three genotypic groups were divided into low vs high (< or > 130 cm2) VAT accumulation. The amount of VAT explained 7.6% and 9.4% of he variation in plasma HDL and HDLz-chol levels (p < 0.001). No significant effect of the genotype was observed on HDL-chol levels when VAT accumulation was taken into account. The CETP-TaqIB genotype explained 4.5% of the variation in plasma HDLZ-chol levels (p < 0.05). Essentially similar results were obtained when subjects were divided on the basis of the median value of fasting insulin levels, the CETP-TaqIB genotype explaining 9.3% (p < 0.01) of the variation in plasma HDLZ-chol levels. These results suggest that the CETP-TaqIB polymorphism influences the magnitude of the decrease in plasma HDL-chol levels observed in visceral obesity.
7 Age-related decline in plasma CETP and CETP mRNA expression in human adipose tissue
T. Radeau, M. Robb, P. Lau, J. Borthwick, Ottawa Heart Institute, Ottawa, Canada
R. McPherson.
Vniversity
of
LIPID-LOWERING
Adipose tissue is an important site of CETP synthesis. However, it is not known to what extend adipose tissue CETP contributes to plasma pool of CETP in man Aging is often associated with changes in adipose tissue composition and function. We have determined adipose tissue CETP mRNA concentration by RNase protection assay and plasma levels of CETP by radio-immunoassay as well as plasma lipoproteins in 12 middle aged and elderly subjects with stable coronary heart disease at the time of coronary artery bypass surgery. Plasma concentrations of CETP were highly correlated with pericardial adipose tissue CETP mRNA abundance (R = 0.89, P < 0.002). CETP mRNA concentrations in adipose tissue were inversely related to age (R = -0.72, P < 0.03) as were plasma concentrations of CETP (R = -0.69, P < 0.012). These relationships were independent of plasma lipids, lipoproteins and body mass index. However, adipocyte size, estimated by adipose tissue triglyceride/mg soluble protein were related to CETP mRNA levels (R = -0.76, P < 0.02). There was also a trend for increased adipocyte size with aging. The age-related decline in plasma concentrations of CETP can be explained in part by a decrease in adipose tissue CETP gene expression.
11th International
Symposium
II2.P.10
DRUGS
Effects of erythromycin on plasma fluvastatin levels: A pharmacokinetic study
J. Aberg U. Eriksson, G. Fager. Clinical Pharmacology, and Development, Astra Hiissle AB, Miilndal, Sweden
Introdu&ion:
Clinical
Research
Fluvastatin (F) is a new hydroxy-methylglutaryl coenzyme A reductase inhibitor. At daily doses of 20 to 80 mg it provides marked reductions of LDL cholesterol similar to other drugs of this class. F is predominantly eliminated by hepatic metabolism and it is therefore important to investigate the potential interaction with other drugs eliminated by hepatic metabolism. Erythromycin (E) is cleared by the liver and a suitable model for cytochrome P450 3A depending drugs. Aim: To study the pharmacokinetics of steady state plasma concentrations of F following concurrent administration of a single dose of E. Study Design: The study was an open, randomized, two-way, cross-over design. Twenty-four healthy male subjects (age 21-34 years) participated. Subjects were given F capsules 40 mg o.d. for 12 days. On day 6 and 12 the subjects were randomly given E tablets 500 mg as a single dose or no E. Blood for F plasma assay was frequently drawn on days 6 and 12.
on Atheroscleroris,
Paris,
October
1997
Tuesday 7 October Lipid-lowering
Pharmacokinetic Calculations: The plasma F data for each dosing interval were treated as single dose data because the concentrations declined to below measurable levels within the dosing interval. The area under the plasma concentration-time curve (AUC) was calculated using the linear trapezoidal rule up to the last measurable level and extrapolated to infinity. The maximum plasma concentration (Cmax) was the highest plasma concentration observed and the time to maximum plasma concentration (tmax) was the time for that measurement. Results: There was no pharmacokinetic interaction between F and E indicated by the similarities of the plasma F profiles. There were no differences in the AUC, Cmax or tmax between the different treatment regimens. Mean AUC f SD for F and F + E was 663 f 329 and 781 Z!Y 345 nmol x h/L, respectively. Conclusion: There was no significant influence from administration of erythromycin on fluvastatin steady state pharmacokinetics. This may suggest that cytochorome P450 3A is not a major route for fluvastatin metabolism.
I2.P
11
Effects of atorvastatin on intracelhdar levels and stability of apolipoprotein B and HMG-CoA reductase in Hep 62 cells
K. Adeli, T. Romain, A. Mohammadi, R.S. Newton’, R. Cheung, J. Macri. Department of Biochemistry, University of Windsor; Windsor, Ontario, Canada; ‘Parke-Davis Pharmaceutical Research Division, Ann Arbor; MI, USA
1997: Posters drugs
119
Therefore HMG-CoA reductase inhibitors halted AP surface coverage and intimal thickening by MO infiltration. Selective statins can indeed modulate AP growth and affect the evolution of atherosclerosis. Work supported by FIS 95-0917, SAL 9410712, Parke-Davis, and FIC-Catalana Occidente.
2 P. 13 El
Effect of lovastatin in hyperlipoproteinaemic
1.2. AndielkovZ, D.D. AndjelkoviC, Department cfPhysiology, Medical
2.2. Kojid, D.M. Faculty, Belgrade
patients
Djurie, M.M. Rosie. Serbia, Yugoslavia
Lovastatin is specific competitive inhibitor of hydroxymethyl.glutaryl CoA reductase, the key enzyme in the process of cholesterol synthesis in hepatocytes. Concentrations of cholesterol, triglycerides, HDL-, LDL-cholesterol, apoproteins A, A-I and B and transaminases, were determinated in serum of patients, before and after therapy. Therapy with lovastatin (20 mg/day) was performed during at lealit a month with simultaneous application of diet on adult male and female population (52-76 years) with confirmed hyperlipoproteinaemia type II a and II b. The research provide that lovastatin significantly reduces the values of total cholesterol (7.41 f 0.17 mmol/l vs. 4.99 f 0.35 mmolll), LDL-cholesterol (5.44 f 0.21 mmolil vs. 3.22 f 0.4 mmol/l), apoprotein B (1.97 f 0.19 mmol/l vs. 1.35 f 0.20 mmol/l) and triglycerides (2.21 f 0.21 vs. I.64 & 0.24 mmol/I) while values of HDL-cholesterol, apoproteins A and A-I transaminases weren’t significantly changed (p > 0.05).
We investigated the effect of atorvastatin, a potent HMG-CoA reductase inhibitor, on expression of apolipoprotein B (apoB) and HMG-CoA reductase in HepG2 cells. Cells were pre-treated with atorvastatin (0.1-10 @M) for 18 h, pulsed with [35S] methionine, and chased for various time periods. In some experiments cells were permeabilized with digitonin (50 &ml, 10 min) before the chase. The accumulation and degradation of apoB and HMG-CoA reductase were monitored over 2 h. Atorvastatin did not influence the synthesis of apoB, but reduced the extracellular secretion of apoB. In addition atorvastatin stimulated the expression of HMG-CoA reductase. Atorvastatin had a significant stimulatory effect on HMG-CoA reductase protein levels (% increase over control: atorvastatin 30.6 f 8.9%; n = 4). ApoB stability was decreased with atorvastatin at 10 WM (% apoB remaining: control 36.45 f 1.45; atorvastatin 16.4 i 5.1; n = 3) (atorvastatin as a percentage of control: 44.9%). The stability of HMG-CoA reductase was not influenced by atorvastatin. Atorvastatin reduced the intracellular levels of cholesterol (1.9 fold) and cholesterol ester (4.3 fold) in HepG2 cells but not that of triglycerides, suggesting that the effects on apoB may be mediated through changes in intracellular levels of cholesterol and/or cholesterol ester. Overall, the data suggest that atorvastatin reduced the secretion of apoB by enhancing the degradation of the protein. Atorvastatin had an inhibitory effect on apoB and an inductive effect on intracellular levels of HMG-CoA reductase. The low inductive effect of atorvastatin on HMG-CoA reductase protein may contribute to the higher hypolipidemic efficacy of this drug.
We evaluated the safety profile of atorvastatin, a new HMG-CoA reductase inhibitor (statin), in patients with lipid disorders. In an integrated database of 21 completed studies (2502 atorvastatin-treated patients), 99% df patients received atorvastatin 10 mg through 80 mg/day. atorvastatin was well tolerated with less than 28% withdrawing due to adverse events (AE) considered associated with drug use. The AE profile for atorvastatin was similar to of other statins testeti; 20% of patients in both groups experienced drug associated AEs. The most common AEs were constipation, flatulence, dyspepsia, and abdominal pain. Approximately 5% of atorvastatin-treated patients had serious AEs, with only 2 events considered possibly related to treatment. Including data from ongoing trials (for a total of 4271 atorvastatin-treated patients), 30 (0.7%) patients experienced confirmed alanine aminotmnsferase levels of >3 times the upper limit of normal. The majority of elevations occurred within 16 weeks of treatment initiation. No patient had a conclusive characterization of drug inducesi myopathy. In conclusion, the safety profile of atorvastatin was the same as other marketed statins.
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inhibitors of hydroxymethyl glutaryl-CoA reductase as modulators of intimal thickening in diet-induced atherosclerosis
J. AlMn L. Badimon. Barcelona, Spain
Cardiovascular
Research
Center,
15
D.M.
Black, Division
J.W. Nawrocki. Parke-Davis of Warner-Lambert Company,
Ann Arbor,
‘Iwo-year comparison of safety and efficacy of atorvastatin and lovastatin
R.G. Bakker-Arkema, L. Shurzinske, M. Davidson, J. McKenney, E. Stein, H. Schrott, D.M. Black. Parke-Davis Pharmaceutical Research, Division of Warner Lambert Company, Ann Arbor; Michigan, USA
Inhibitors of HMG-CoA reductase are used as cholesterol lowering drugs, and some of them have showed to decrease cardiovascular morbidity and mortality, Their mechanism might be related to the inhibition of atherosclerotic plaque (AP) growth which in turn leads to ischemic episodies. We have studied the effect of Atorvastatin (A) and Simvastatin (S) on AP composition and thickness in rabbits fed hyperlipemic diet (0.5% cholesterol, 15% coconut oil). A (2.5 mg/kg/day, n = 5), S (2.5 mg/kglday, n = 5), or placebo (n = 6) were orally administered during 60 days. Cholesterol levels were significantly reduced by both drugs (A 20%, S 30%) and mural thrombosis (platelet deposition on injured vessel wall at arterial flow conditions) was more effectively reduced by A than by S. At sacrifice, aortas were removed, tixed, OTC included, and sectioned. Sections were stained with Mason’s technique and intimal thickness measured by computer assisted microscopy; immunofluorescence was used for macropbage (RAM II, Dako) smooth muscle cells @-a&in, Dako) and fibrinogen (Dako) localization; and, northern blots were run to assay MCPexpression. Both statins inhibit progression of intimal thickening by 30% and 60% [for A and S (p < 0.05), respectively). Plaques were heavenly infiltrated with MO and Fg irrespectively of treatment, while SMC were scattered within the thickened intimas. MCP was expressed similarly in the three groups. Symposium
An overview of the clinical safety profile of atorvastatin a new, more effective HMG-CoA reductase inhibitor
R.G. Bakker..Arkema Pharmaceutiz&ch, Michigan, USA
2.P
CSIC-HSCSP-VAB,
I1 th International
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In this 2-year study, 787 patients with hypercholesterolemia received either atorvastatin 10 mg to 80 mg/day (623 patients) or lovastatin 20 mg to 80 mg/day (164 patients). Patients were median age of 59 years, Fredrickson Type IIa or IIb. Patients started on the lowest dose and increased their dose until they met their National Cholesterol Education Panel (NCEP) LDL-C goal. At the end of 2 years, 88% of patients on atorvastatin (63% on 10 mg/day) and 74% on lovastatin (39% on 20 mg/day) met their NCEP goal. Atorvastatin reduced LDL-C by 39% compared to 32% by lovastatin (p < 0.01). The safety profile was similar between the 2 compounds. Three patients (0.5%) treated with atorvazjtatin and 4 patients (2.4%) treated with lovastatin had a confirmed alanine aminotransferase value >3 times the upper limit of normal (x ULN). No atorvastatin treated patients had a confirmed CPK elevation > 10 x ULN. Atorvastatin enables more patients to reach NCEP goals while maintaining a safety profile comparable to lovastatin.
on Atherosclerosis,
Paris,
October
1997