Inhibition of HMG-CoA reductase by atorvastatin decreases both VLDL and LDL apolipoprotein B production in miniature pigs

Atorvastatin impairs liver mitochondrial function in obese Göttingen Minipigs but heart and skeletal muscle are not affected

Statins lower the risk of cardiovascular events but have been associated with mitochondrial functional changes in a tissue-dependent manner. We investigated tissue-specific modifications of mitochondrial function in liver, heart and skeletal muscle mediated by chronic statin therapy in a Göttingen Minipig model. We hypothesized that statins enhance the mitochondrial function in heart but impair skeletal muscle and liver mitochondria. Mitochondrial respiratory capacities, citrate synthase activity, coenzyme Q10 concentrations and protein carbonyl content (PCC) were analyzed in samples of liver, heart and skeletal muscle from three groups of Göttingen Minipigs: a lean control group (CON, n = 6), an obese group (HFD, n = 7) and an obese group treated with atorvastatin for 28 weeks (HFD + ATO, n = 7). Atorvastatin concentrations were analyzed in each of the three tissues and in plasma from the Göttingen Minipigs. In treated minipigs, atorvastatin was detected in the liver and in plasma. A significant reduction in complex I + II-supported mitochondrial respiratory capacity was seen in liver of HFD + ATO compared to HFD (P = 0.022). Opposite directed but insignificant modifications of mitochondrial respiratory capacity were seen in heart versus skeletal muscle in HFD + ATO compared to the HFD group. In heart muscle, the HFD + ATO had significantly higher PCC compared to the HFD group (P = 0.0323). In the HFD group relative to CON, liver mitochondrial respiration decreased whereas in skeletal muscle, respiration increased but these changes were insignificant when normalizing for mitochondrial content. Oral atorvastatin treatment in Göttingen Minipigs is associated with a reduced mitochondrial respiratory capacity in the liver that may be linked to increased content of atorvastatin in this organ.

Fractional turnover of apolipoprotein(a) and apolipoprotein B-100 within plasma lipoprotein(a) particles in statin-treated patients with elevated and normal Lp(a) concentration

CONTEXT

Lipoprotein(a) [Lp(a)] is a highly atherogenic lipoprotein characterized by apolipoprotein(a) [apo(a)] covalently bounded to apoB-100 (apoB). However, the metabolism of apo(a) and apoB within plasma Lp(a) particles in patients on statins remains unclear.

METHODS

The kinetics of Lp(a)-apo(a) and Lp(a)-apoB were determined in 20 patients with elevated Lp(a) (≥0.8 g/L; n = 10) and normal Lp(a) (≤0.3 g/L; n = 10) using stable isotope techniques and compartmental modeling. Plasma apo(a) concentration was measured using liquid chromatography-mass spectrometry. All patients were on statin therapy and were studied in the fasting state.

RESULTS

The fractional catabolic rate (FCR) of Lp(a)-apo(a) was not significantly different from that of Lp(a)-apoB in statin-treated patients with elevated or normal Lp(a) (P > 0.05 in both). Lp(a)-apo(a) FCR was significantly correlated with Lp(a)-apoB in patients with elevated and normal Lp(a) concentrations (r = 0.970 and r = 0.979, respectively; all P < 0.001) with Lin's concordance test showing substantial agreement between the FCRs of Lp(a)-apo(a) and Lp(a)-apoB in patients with elevated and normal Lp(a) concentrations (r_c = 0.978 and r_c = 0.966, respectively).

CONCLUSION

Our data indicate that the apo(a) and apoB proteins within Lp(a) particles have similar FCR and are therefore tightly coupled as an Lp(a) holoparticle in statin-treated patients with elevated and normal Lp(a) concentrations.

Association of atorvastatin with the risk of hepatotoxicity: a pilot prescription sequence symmetry analysis

Purpose

This study aimed to evaluate Atorvastatin (ATO)-associated hepatotoxicity using prescription sequence symmetry analysis (PSSA), based on a health insurance database of a Chinese population living in Jiangsu Province, China.

Methods

Patients prescribed ATO and hepatoprotective drugs in 2017 were identified, and the run-in period was determined based on the "waiting-time" distribution. Adjusted sequence ratio (ASR) and 95% confidence interval (95% CI) were calculated to estimate the risk of ATO-associated hepatotoxicity under different time intervals or based on gender and age stratification.

Results

A total of 2,549 patients, with 1,518 filling the ATO prescription first and 1,031 filling the ATO prescription second, were analyzed. After setting the run-in period as 30 days and the time interval as 15, 30, 60, 90, 120, and 180 days, the ASRs were 1.492 (95% CI: 1.367-1.652), 1.399 (95% CI: 1.308-1.508), 1.280 (95% CI: 1.213-1.357), 1.292 (95% CI: 1.234-1.356), 1.278 (95% CI: 1.226-1.336), and 1.274 (95% CI: 1.229-1.323), respectively. No significant difference was observed between different genders and ages (χ²=0.161, P=0.688; χ²=1.565, P=0.211, respectively).

Conclusion

This is the first study conducted in a real-world setting to evaluate the relationship between ATO and hepatotoxicity using the PSSA in a Chinese population. We found a 1.3- to 1.5-fold increase in risk of hepatotoxicity following ATO, with the greater risk occurring within the first 30 days of treatment.

Effect of dietary n-3 fatty acids supplementation on fatty acid metabolism in atorvastatin-administered SHR.Cg-Leprcp/NDmcr rats, a metabolic syndrome model

The effects of cholesterol-lowering statins, which substantially benefit future cardiovascular events, on fatty acid metabolism have remained largely obscured. In this study, we investigated the effects of atorvastatin on fatty acid metabolism together with the effects of TAK-085 containing highly purified eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) ethyl ester on atorvastatin-induced n-3 polyunsaturated fatty acid lowering in SHR.Cg-Lepr^cp/NDmcr (SHRcp) rats, as a metabolic syndrome model. Supplementation with 10mg/kg body weight/day of atorvastatin for 17 weeks significantly decreased plasma total cholesterol and very low density lipoprotein cholesterol. Atorvastatin alone caused a subtle change in fatty acid composition particularly of EPA and DHA in the plasma, liver or erythrocyte membranes. However, the TAK-085 consistently increased both the levels of EPA and DHA in the plasma, liver and erythrocyte membranes. After confirming the reduction of plasma total cholesterol, 300mg/kg body weight/day of TAK-085 was continuously administered for another 6 weeks. Supplementation with TAK-085 did not decrease plasma total cholesterol but significantly increased the EPA and DHA levels in both the plasma and liver compared with rats administered atorvastatin only. Supplementation with atorvastatin alone significantly decreased sterol regulatory element-binding protein-1c, Δ5- and Δ6-desaturases, elongase-5, and stearoyl-coenzyme A (CoA) desaturase-2 levels and increased 3-hydroxy-3-methylglutaryl-CoA reductase mRNA expression in the liver compared with control rats. TAK-085 supplementation significantly increased stearoyl-CoA desaturase-2 mRNA expression. These results suggest that long-term supplementation with atorvastatin decreases the EPA and DHA levels by inhibiting the desaturation and elongation of n-3 fatty acid metabolism, while TAK-085 supplementation effectively replenishes this effect in SHRcp rat liver.

Corn silk extract improves cholesterol metabolism in C57BL/6J mouse fed high-fat diets

BACKGROUND/OBJECTIVES

Corn silk (CS) extract contains large amounts of maysin, which is a major flavonoid in CS. However, studies regarding the effect of CS extract on cholesterol metabolism is limited. Therefore, the purpose of this study was to determine the effect of CS extract on cholesterol metabolism in C57BL/6J mouse fed high-fat diets.

MATERIALS/METHODS

Normal-fat group fed 7% fat diet, high-fat (HF) group fed 25% fat diet, and high-fat with corn silk (HFCS) group were orally administered CS extract (100 mg/kg body weight) daily. Serum and hepatic levels of total lipids, triglycerides, and total cholesterol as well as serum free fatty acid, glucose, and insulin levels were determined. The mRNA expression levels of acyl-CoA: cholesterol acyltransferase (ACAT), cholesterol 7-alpha hydroxylase (CYP7A1), farnesoid X receptor (FXR), lecithin cholesterol acyltransferase (LCAT), low-density lipoprotein receptor, 3-hyroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase), adiponectin, leptin, and tumor necrosis factor α were determined.

RESULTS

Oral administration of CS extract with HF improved serum glucose and insulin levels as well as attenuated HF-induced fatty liver. CS extracts significantly elevated mRNA expression levels of adipocytokines and reduced mRNA expression levels of HMG-CoA reductase, ACAT, and FXR. The mRNA expression levels of CYP7A1 and LCAT between the HF group and HFCS group were not statistically different.

CONCLUSIONS

CS extract supplementation with a high-fat diet improves levels of adipocytokine secretion and glucose homeostasis. CS extract is also effective in decreasing the regulatory pool of hepatic cholesterol, in line with decreased blood and hepatic levels of cholesterol though modulation of mRNA expression levels of HMG-CoA reductase, ACAT, and FXR.

Loss of P2X7 nucleotide receptor function leads to abnormal fat distribution in mice

The P2X7 receptor is an ATP-gated cation channel expressed by a number of cell types. We have shown previously that disruption of P2X7 receptor function results in downregulation of osteogenic markers and upregulation of adipogenic markers in calvarial cell cultures. In the present study, we assessed whether loss of P2X7 receptor function results in changes to adipocyte distribution and lipid accumulation in vivo. Male P2X7 loss-of-function (KO) mice exhibited significantly greater body weight and epididymal fat pad mass than wild-type (WT) mice at 9 months of age. Fat pad adipocytes did not differ in size, consistent with adipocyte hyperplasia rather than hypertrophy. Histological examination revealed ectopic lipid accumulation in the form of adipocytes and/or lipid droplets in several non-adipose tissues of older male KO mice (9-12 months of age). Ectopic lipid was observed in kidney, extraorbital lacrimal gland and pancreas, but not in liver, heart or skeletal muscle. Specifically, lacrimal gland and pancreas from 12-month-old male KO mice had greater numbers of adipocytes in perivascular, periductal and acinar regions. As well, lipid droplets accumulated in the renal tubular epithelium and lacrimal acinar cells. Blood plasma analyses revealed diminished total cholesterol levels in 9- and 12-month-old male KO mice compared with WT controls. Interestingly, no differences were observed in female mice. Moreover, there were no significant differences in food consumption between male KO and WT mice. Taken together, these data establish novel in vivo roles for the P2X7 receptor in regulating adipogenesis and lipid metabolism in an age- and sex-dependent manner.

Naringenin prevents cholesterol-induced systemic inflammation, metabolic dysregulation, and atherosclerosis in Ldlr⁻/⁻ mice

Obesity-associated chronic inflammation contributes to metabolic dysfunction and propagates atherosclerosis. Recent evidence suggests that increased dietary cholesterol exacerbates inflammation in adipose tissue and liver, contributing to the proatherogenic milieu. The ability of the citrus flavonoid naringenin to prevent these cholesterol-induced perturbations is unknown. To assess the ability of naringenin to prevent the amplified inflammatory response and atherosclerosis induced by dietary cholesterol, male Ldlr⁻/⁻ mice were fed either a cholesterol-enriched high-fat or low-fat diet supplemented with 3% naringenin for 12 weeks. Naringenin, through induction of hepatic fatty acid (FA) oxidation and attenuation of FA synthesis, prevented hepatic steatosis, hepatic VLDL overproduction, and hyperlipidemia induced by both cholesterol-rich diets. Naringenin attenuated hepatic macrophage infiltration and inflammation stimulated by dietary cholesterol. Insulin resistance, adipose tissue expansion, and inflammation were alleviated by naringenin. Naringenin attenuated the cholesterol-induced formation of both foam cells and expression of inflammatory markers in peritoneal macrophages. Naringenin significantly decreased atherosclerosis and inhibited the formation of complex lesions, which was associated with normalized aortic lipids and a reversal of aortic inflammation. We demonstrate that in mice fed cholesterol-enriched diets, naringenin attenuates peripheral and systemic inflammation, leading to protection from atherosclerosis. These studies offer a therapeutically relevant alternative for the prevention of cholesterol-induced metabolic dysregulation.

Altered composition of triglyceride-rich lipoproteins and coronary artery disease in a large case-control study

BACKGROUND

Traditional beta-quantification of plasma lipoproteins by ultracentrifugation separates triglyceride-rich lipoproteins (TGRL) from higher density lipoproteins. The cholesterol in the TGRL fraction is referred to as measured very low-density lipoprotein cholesterol (VLDL-C) recognizing that other TGRL may be present. The measured VLDL-C to total plasma triglyceride (VLDL-C/TG) has long been considered an index of average TGRL composition with abnormally high VLDL-C/TG ratios (>or=0.30 with TG>150mg/dL) indicative of atherogenic remnant accumulation (type III hyperlipidemia). However, virtually no reports are available which examine potential associations between CAD and VLDL-C/TG at the lower end of the spectrum.

METHODS AND RESULTS

We performed ultracentrifugation in 1170 cases with premature-onset, familial CAD and 1759 population-based controls and examined the VLDL-C/TG ratio as an index of TGRL composition. As expected, we found very high CAD risk associated with severe type III hyperlipidemia (OR 10.5, p=0.02). Unexpectedly, however, we found a robust, graded, and independent association between CAD risk and lower than average VLDL-C/TG ratios (p<0.0001 as ordered categories or as a continuous variable). Among those in the lowest VLDL-C/TG category (a ratio <0.12), CAD risk was clearly increased (OR 4.5, 95% CI 2.9-6.9) and remained significantly elevated in various subgroups including those with triglycerides below 200mg/dl, in males and females separately, as well as among those with no traditional CAD risk factors (OR 5.8, 95% CI 1.5-22). Significant compositional differences by case status were confirmed in a subset whose samples were re-spun with measurement of lipids and apolipoprotein B (apo B) in each subfraction.

CONCLUSIONS

We found a strong, graded, independent, and robust association between CAD and lower VLDL-C/TG ratios. We consider this a novel, hypothesis-generating observation which will hopefully generate additional future studies to provide confirmation and further insight into potential mechanisms.

Atorvastatin accelerates extracellular nucleotide degradation in human endothelial cells

HMG-CoA reductase inhibitors (statins) exert pleiotropic effects in the cardiovascular system beyond its cholesterol-lowering action. We aimed to investigate how atorvastatin affects extracellular nucleotide degradation in human endothelial cells, as increased activity of this pathway would facilitate conversion of pro-inflammatory nucleotides into anti-inflammatory adenosine. Primary cultures of human endothelial cells were treated with 1 microM, 10 microM and 100 microM atorvastatin for 24 h. Enzyme assays were performed as well as intact cell studies, to evaluate capacity of cells to degrade ATP to adenosine. Atorvastatin significantly increased ATP breakdown and adenosine formation in the medium of intact cells in a dose-dependent manner. The activities of ATPase, ADPase and ecto-5'-nucleotidase (eN) in cell homogenates following Atorvastatin treatment were also increased while no change was observed in the lactate dehydrogenase activity. We suggest a new mechanism of protective effect of atorvastatin by activation of endothelial enzymes involved in extracellular nucleotide degradation in human endothelial cells.

Apolipoprotein B and triacylglycerol secretion in human triacylglycerol hydrolase transgenic mice

Apolipoprotein B (apoB)-containing lipoproteins play a critical role in whole body lipid homeostasis and the pathogenesis of atherosclerosis. The assembly of hepatic apoB-containing lipoproteins, VLDL, is governed by the availability of lipids, including triacylglycerol (TG). The majority of TG associated with VLDL is derived from the hepatic cytoplasmic lipid stores by a process involving lipolysis followed by reesterification. Microsomal triacylglycerol hydrolase (TGH) has been demonstrated to play a role in the lipolysis/reesterification process. To evaluate the potential regulatory role of TGH in hepatic VLDL assembly, we developed inducible transgenic mice expressing a human TGH minigene under the control of the mouse metallothionein promoter. Induction of human TGH by zinc resulted in liver-specific expression of the enzyme associated with 3- to 4-fold increases in lipolytic activity that could be attenuated with a TGH-specific inhibitor. Augmented TGH activity led to increased secretion of newly synthesized apoB and plasma TG levels. These results suggest that increased hepatic expression of TGH leads to a more proatherogenic plasma lipid and apoB profile.

Effects of atorvastatin and apoA-I/phosphatidylcholine discs on triglyceride-rich lipoprotein subfractions as characterized by capillary isotachophoresis

BACKGROUND

The present study examined the effects of atorvastatin and the in vitro effect of apolipoprotein (apo) A-I/phosphatidylcholine (POPC) discs on charge-based triglyceride-rich lipoprotein (TRL) subfractions in a patient with type III hyperlipoproteinemia (HLP) and the apoE2/2 phenotype.

METHODS

Charge-based lipoprotein subfractions were characterized by capillary isotachophoresis (cITP). cITP analysis was performed using plasma that had been prestained with a lipophilic dye on a Beckman P/ACE MDQ system.

RESULTS

Treatment with atorvastatin for 4 weeks markedly decreased the slow (s)-migrating TRL subfraction and both fast- and slow-migrating low-density lipoprotein (LDL) subfractions, but did not affect the fast (f)-migrating TRL subfraction in this patient. ApoA-I/POPC discs consisted of two major charge-based subfractions that had the mobility of cITP fTRL and sTRL. Incubation of plasma from this patient in the presence of apoA-I/POPC discs caused not only a reduction in cITP fast- and intermediate-migrating HDL and an increase in cITP sHDL but also a reduction in fTRL and sTRL and an increase in sLDL.

CONCLUSION

Atorvastatin and apoA-I/POPC discs decreased cITP TRL subfractions in a complementary manner, suggesting that the combination of apoA-I/POPC discs and atorvastatin could be a promising therapeutic approach for hypertriglyceridemia.

Plasma cholesterol is hyperresponsive to statin in ABCG5/ABCG8 transgenic mice

Interindividual variation exists in response to statin therapy. It has been hypothesized that subjects with higher baseline cholesterol synthesis rates are more sensitive to statins. To directly test this hypothesis, mice overexpressing the heterodimeric ATP-binding cassette (ABC) transporter G5/G8 (G5G8(Tg) mice) were treated with lovastatin because they have a compensatory increase in cholesterol biosynthesis as a result of increased cholesterol excretion into bile and feces. As expected, lovastatin treatment did not alter plasma and hepatic cholesterol levels in wild-type mice. Interestingly, this treatment significantly reduced plasma concentration and hepatic content of cholesterol by 42% and 17.3%, respectively, in the statin-treated versus untreated G5G8(Tg) mice despite a greater feedback upregulation of genes in the pathway of cholesterol biosynthesis in the lovastatin-treated G5G8(Tg) mice. The reduced plasma cholesterol concentration is unlikely to be attributed to LDL and HDL receptors because the protein levels of both receptors remained unchanged. Surprisingly, statin treatment resulted in an increase in biliary cholesterol concentration, which was associated with an upregulation in hepatic mRNA and protein levels of ABCG5 and ABCG8, and in hepatic mRNA levels of Niemann-Pick C1-Like 1 (NPC1L1), a gene that is required for intestinal cholesterol absorption. In conclusion, mice with higher endogenous cholesterol synthesis rates are more sensitive to statin. A synergistic hypocholesterolemic effect could be potentially achieved in humans by simultaneously inhibiting cholesterol biosynthesis and promoting ABCG5/ABCG8-mediated cholesterol excretion.

Effects of atorvastatin on lipid metabolism in normolipidemic and hereditary hyperlipidemic, non-laying hens

As a result of a hereditable point mutation in the oocyte very low density lipoprotein (VLDL) receptor, sexually mature restricted ovulator (RO) female chickens (Gallus gallus), first described as a non-laying strain, exhibit endogenous hyperlipidemia and develop atherosclerotic lesions. In a 20-day study, RO hens and their normolipidemic (NL) siblings were fed either a control diet, or the control diet supplemented with 0.06% atorvastatin (AT), a potent 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) inhibitor. Compared to NL hens, RO birds exhibited greatly elevated baseline plasma total cholesterol (CHOL) and triglyceride (TG) concentrations (1.56 vs. 4.55 g/l and 30.7 vs. 138.4 g/l, respectively). AT attenuated plasma CHOL and TG concentrations by 60.3% and 70.1%, respectively, in NL hens and by 45.1% and 34.3%, respectively, in RO hens. Messenger RNA levels of several key genes involved in hepatic VLDL assembly were suppressed in RO vs. NL hens, but were unaffected by AT. In contrast, AT elevated liver HMGR mRNA levels in NL and RO birds, but only NL hens exhibited an AT-associated increase in hepatic HMGR immunoreactive protein levels. Down-regulation of HMGR gene expression due to higher baseline levels of circulating CHOL may explain why RO birds responded less robustly than NL hens to AT administration.

Red wine polyphenolics suppress the secretion of ApoB48 from human intestinal CaCo-2 cells

Epidemiological studies suggest that the consumption of red wine lowers the risk of cardiovascular disease. Although the cardioprotective effect of red wine has been attributed to its polyphenolic content, presently, very little is known about the mechanisms by which these compounds benefit the cardiovascular system. Therefore, the aim of this study was to elucidate whether red wine polyphenolics attenuate the synthesis and secretion of proatherogenic chylomicrons from intestinal cells. Apolipoprotein B48 levels (marker of intestinal chylomicrons), quantitated by western blotting, were significantly reduced by 30% in cultured CaCo-2 cells and medium when cells were incubated with either dealcoholized red wine, alcoholized red wine, or atorvastatin compared with controls. Intracellular cholesterol availability was also attenuated in cells incubated with dealcoholized red wine (72.5%), alcoholized red wine (81.5%), and atorvastatin (83.5%) compared to control cells. Collectively, this study suggests that red wine polyphenolics downregulate the production of atherogenic chylomicrons from intestinal cells, which may explain the reduced CVD mortality rates following its consumption.

Rosuvastatin Reduces Plasma Lipids by Inhibiting VLDL Production and Enhancing Hepatobiliary Lipid Excretion in ApoE*3-Leiden Mice

The present study was designed to investigate the lipid-lowering properties and mechanisms of action of a new HMG-CoA reductase inhibitor, rosuvastatin, in female ApoE*3-Leiden transgenic mice. Mice received a high fat/cholesterol (HFC) diet containing either rosuvastatin (0 [control], 0.00125%, 0.0025%, or 0.005% [w/w]) or 0.05% (w/w) lovastatin. The highest dose of rosuvastatin reduced plasma cholesterol and triglyceride levels by 39% and 42%, respectively, compared with the HFC control. Lovastatin had no effect on plasma cholesterol and triglyceride levels. In ApoE*3-Leiden mice on a chow diet, rosuvastatin (0.005% [w/w]) decreased plasma cholesterol levels by 35% without having an effect on triglyceride levels. On a chow diet, expression of genes involved in cholesterol biosynthesis and uptake in the liver was increased by rosuvastatin. Further mechanistic studies in HFC-fed mice showed that rosuvastatin treatment resulted in decreased hepatic VLDL-triglyceride and VLDL-apolipoprotein B production. VLDL lipid composition remained unchanged, indicating a reduction in the number of VLDL particles secreted. Lipolytic activity and expression of genes involved in cholesterol and triglyceride synthesis and beta-oxidation of fatty acids in the liver were not affected by rosuvastatin treatment, and hepatic lipid content did not change. However, activity of hepatic diacylglycerol acyltransferase was significantly decreased by 25% after rosuvastatin treatment. Moreover, biliary excretion of cholesterol, phospholipids, and bile acids was increased during treatment. The results indicate that rosuvastatin treatment in ApoE*3-Leiden mice on a HFC diet leads to redistribution of cholesterol and triglycerides in the body, both by reduced hepatic VLDL production and triglyceride synthesis and by enhanced hepatobiliary removal of cholesterol, bile acids, and phospholipids, resulting in substantial reductions in plasma cholesterol and triglyceride levels.

Overexpression of human diacylglycerol acyltransferase 1, acyl-coa:cholesterol acyltransferase 1, or acyl-CoA:cholesterol acyltransferase 2 stimulates secretion of apolipoprotein B-containing lipoproteins in McA-RH7777 cells

The relative importance of each core lipid in the assembly and secretion of very low density lipoproteins (VLDL) has been of interest over the past decade. The isolation of genes encoding diacylglycerol acyltransferase (DGAT) and acyl-CoA:cholesterol acyltransferases (ACAT1 and ACAT2) provided the opportunity to investigate the effects of isolated increases in triglycerides (TG) or cholesteryl esters (CE) on apolipoprotein B (apoB) lipoprotein biogenesis. Overexpression of human DGAT1 in rat hepatoma McA-RH7777 cells resulted in increased synthesis, cellular accumulation, and secretion of TG. These effects were associated with decreased intracellular degradation and increased secretion of newly synthesized apoB as VLDL. Similarly, overexpression of human ACAT1 or ACAT2 in McA-RH7777 cells resulted in increased synthesis, cellular accumulation, and secretion of CE. This led to decreased intracellular degradation and increased secretion of VLDL apoB. Overexpression of ACAT2 had a significantly greater impact upon assembly and secretion of VLDL from liver cells than did overexpression of ACAT1. The addition of oleic acid (OA) to media resulted in a further increase in VLDL secretion from cells expressing DGAT1, ACAT1, or ACAT2. VLDL secreted from DGAT1-expressing cells incubated in OA had a higher TG:CE ratio than VLDL secreted from ACAT1- and ACAT2-expressing cells treated with OA. These studies indicate that increasing DGAT1, ACAT1, or ACAT2 expression in McA-RH7777 cells stimulates the assembly and secretion of VLDL from liver cells and that the core composition of the secreted VLDL reflects the enzymatic activity that is elevated.

The effect of high dose atorvastatin therapy on lipids and lipoprotein subfractions in overweight patients with type 2 diabetes

Few data are available on the effects of high dose statin therapy on lipoprotein subfractions in type 2 diabetes. In a double blind randomised placebo-controlled trial we have studied the effects of 80 mg atorvastatin over 8 weeks on LDL, VLDL and HDL subfractions in 40 overweight type 2 diabetes patients. VLDL and LDL subfractions were prepared by density gradient ultracentrifugation. Triglycerides, cholesterol, total protein and phospholipids were measured and mass of subfractions calculated. HDL subfractions were prepared by precipitation. Atorvastatin 80 mg produced significant falls in LDL subfractions (LDL(1) 66.2 mg/dl:36.6 mg/dl, LDL(2) 118:56.6 mg/dl, LDL(3) 36.9:19.9 mg/dl all P < 0.01 relative to placebo) and VLDL subfractions (VLDL(1) 55:22.1 mg/dl, VLDL(2) 40.1:19.1 mg/dl, VLDL(3) 52.6:30 mg/dl all P < 0.01 relative to placebo). There was no change in the proportion of LDL present as LDL(3). There was a reduction in the proportion of VLDL as VLDL(1) and a reciprocal increase in the proportion as VLDL(3). Changes in VLDL subfractions were associated with changes in lipid composition, particularly a reduction in cholesterol ester and a reduction in the cholesterol ester/triglyceride ratio. Effects on HDL subfractions were largely neutral. High dose atorvastatin produces favourable effects on lipoprotein subfractions in type 2 diabetes which may enhance antiatherogenic potential.

ABCA1-dependent lipid efflux to apolipoprotein A-I mediates HDL particle formation and decreases VLDL secretion from murine hepatocytes

High levels of expression of the ATP binding cassette transporter A1 (ABCA1) in the liver and the need to over- or underexpress hepatic ABCA1 to impact plasma HDL levels in mice suggest a major role of the liver in HDL formation and in determining circulating HDL levels. Cultured murine hepatocytes were used to examine the role of hepatic ABCA1 in mediating the lipidation of apolipoprotein A-I (apoA-I) for HDL particle formation. Exogenous apoA-I stimulated cholesterol efflux to the medium from wild-type hepatocytes, but not from ABCA1-deficient (abca1(-/-)) hepatocytes. ApoA-I induced the formation of new HDL particles and enhanced the lipidation of endogenously secreted murine apoA-I in ABCA1-expressing but not abca1(-/-) hepatocytes. ABCA1-dependent cholesterol mobilization to apoA-I increased new cholesterol synthesis, indicating depletion of the regulatory pool of hepatocyte cholesterol during HDL formation. Secretion of triacylglycerol and apoB was decreased following apoA-I incubation with ABCA1-expressing but not abca1(-/-) hepatocytes. These results support a major role for hepatocyte ABCA1 in generating a critical pool of HDL precursor particles that enhance further HDL generation and passive cholesterol mobilization in the periphery. The results also suggest that diversion of hepatocyte cholesterol into the "reverse" cholesterol transport pathway diminishes cholesterol availability for apoB-containing lipoprotein secretion by the liver.

Cholesterol-lowering properties of Ganoderma lucidum in vitro, ex vivo, and in hamsters and minipigs

INTRODUCTION

There has been renewed interest in mushroom medicinal properties. We studied cholesterol lowering properties of Ganoderma lucidum (Gl), a renowned medicinal species.

RESULTS

Organic fractions containing oxygenated lanosterol derivatives inhibited cholesterol synthesis in T9A4 hepatocytes. In hamsters, 5% Gl did not effect LDL; but decreased total cholesterol (TC) 9.8%, and HDL 11.2%. Gl (2.5 and 5%) had effects on several fecal neutral sterols and bile acids. Both Gl doses reduced hepatic microsomal ex-vivo HMG-CoA reductase activity. In minipigs, 2.5 Gl decreased TC, LDL- and HDL cholesterol 20, 27, and 18%, respectively (P < 0.05); increased fecal cholestanol and coprostanol; and decreased cholate.

CONCLUSIONS

Overall, Gl has potential to reduce LDL cholesterol in vivo through various mechanisms. Next steps are to: fully characterize bioactive components in lipid soluble/insoluble fractions; evaluate bioactivity of isolated fractions; and examine human cholesterol lowering properties. Innovative new cholesterol-lowering foods and medicines containing Gl are envisioned.

Effects of atorvastatin versus fenofibrate on apoB-100 and apoA-I kinetics in mixed hyperlipidemia

Kinetics of apo B and apo AI were assessed in 8 patients with mixed hyperlipidemia at baseline and after 8 weeks of atorvastatin 80 mg q.d. and micronised fenofibrate 200 mg q.d. in a cross-over study. Both increased hepatic production and decreased catabolism of VLDL accounted for elevated cholesterol and triglyceride concentrations at baseline. Atorvastatin significantly decreased triglyceride, total, VLDL and LDL cholesterol and apo B concentrations (-65%, -36%, -57%, -40% and -33%, respectively, P<0.05). Kinetic analysis revealed that atorvastatin stimulated the catabolism of apo B containing lipoproteins, enhanced the delipidation of VLDL1 and decreased VLDL1 production. Fenofibrate lowered triglycerides and VLDL cholesterol (-57% and -64%, respectively, P<0.05) due to enhanced delipidation of VLDL1 and VLDL2 and increased VLDL1 catabolism. Changes of HDL particle composition accounted for the increase of HDL cholesterol during atorvastatin and fenofibrate (18% and 23%, P<0.01). Only fenofibrate increased apo AI concentrations through enhanced apo AI synthesis (45%, P<0.05). We conclude that atorvastatin exerts additional beneficial effects on the metabolism of apo B containing lipoproteins unrelated to an increase in LDL receptor activity. Fenofibrate but not atorvastatin increases apo AI production and plasma turnover.

Pravastatin Sodium, an Inhibitor of HMG-CoA Reductase, Decreases HDL Cholesterol by Transfer of Cholesteryl Ester from HDL to VLDL in Japanese White Rabbits

In a recent paper, we reported that pravastatin sodium (pravastatin), an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme. A reductase, decreases the concentrations of low density lipoprotein (LDL) cholesterol through an LDL receptor pathway in Japanese White (JW) rabbits, whereas this agent lowers high density lipoprotein (HDL) cholesterol in a manner correlated with a reduction of very low density lipoprotein (VLDL) cholesterol secretion from the liver. In the present study, we administered pravastatin to JW rabbits at 30 mg/kg for 14 days and examined further the mechanisms for the reduction of HDL cholesterol. A striking finding was that the 4-day administration of pravastatin at 30 mg/kg selectively decreased the concentration of HDL cholesterol. Since 4-day administration of pravastatin to JW rabbits did not change the concentrations of hepatic LDL receptor proteins, these receptors were not likely to be involved in the reduction of HDL cholesterol. Another important finding was that pravastatin suppressed VLDL cholesteryl ester (CE) secretion from the liver, but not that of other VLDL lipids and VLDL proteins, indicating that the CE-poor VLDL particles were secreted by the consecutive administration of pravastatin. There were, however, no differences in the levels of VLDL cholesterol between the control and pravastatin-treated groups over the experimental period of 14 days. These observations raised the possibility that the reduction of HDL cholesterol in the pravastatin-treated group was due to the transfer of CE molecules from HDL particles to these CE-poor VLDL particles. Molecular species analysis supported this notion that the VLDL-CE in the pravastatin-treated group was rich in cholesteryl linoleate, indicating that the CE in this group mainly originated from HDL, whereas the VLDL-CE in the control group was rich in cholesteryl oleate, indicating that the CE in this group originated from the liver. The present study suggests that pravastatin lowers HDL cholesterol by transferring CE from these lipoproteins to VLDL in JW rabbits.

Long-term effect of low-density lipoprotein apheresis in patients with homozygous familial hypercholesterolemia

Patients that are homozygous for familial hypercholesterolemia (FH) exhibit severe hypercholesterolemia, cutaneous and tendon xanthomas and premature atherosclerosis beginning in childhood. They are resistant to drug therapy and low-density lipoprotein (LDL) apheresis is the practical treatment. Here we review the technique of LDL apheresis treatment, the long-term effects of LDL apheresis, the effect of apheresis on pregnancy, and the drugs that have proven beneficial in patients with homozygous FH. We also record our experiences of treating eight homozygous FH patients using the LDL apheresis treatment. Among the eight patients, one has been free from cardiovascular disease and two patients have each regressed once. In two patients, aortic valve stenosis developed and the other two patients died for acute myocardial infarction. Furthermore, two patients delivered healthy babies in spite of coronary artery disease. Thus, LDL apheresis therapy has the possibility of preventing the progression of atherosclerosis, but the prognosis assessed by long-term observation is still not satisfactory. A recent clinical trial showed some efficacy of the combination therapy of LDL apheresis and atorvastatin for reducing serum cholesterol levels in homozygous FH, suggesting that this combination therapy may be useful for prevention of atherosclerosis in patients homozygous for FH.

Effect of atorvastatin on apolipoprotein B100 containing lipoprotein metabolism in type-2 diabetes

Seven hypertriglyceridemic patients with type-2 diabetes were treated with atorvastatin (40 mg/day) for 2 months. Kinetics of apolipoprotein B100 (apoB100)-containing lipoproteins were determined before and after atorvastatin treatment and compared with data obtained in five normolipidemic volunteers. ApoB100 metabolism was studied using stable isotopes and multicompartmental modeling. Compared with normolipidemic obese subjects, type-2 diabetic patients had a higher apoB100 concentration in very low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), and low-density lipoproteins (LDL) (P < 0.005). Kinetic analysis showed an increase in the total apoB100 production rate (P < 0.005) related to VLDL apoB100 overproduction (P < 0.005). Patients were also characterized by a lower fractional catabolic rate (FCR) in VLDL (not significant) or IDL (P < 0.005) mainly related to a decrease in VLDL and IDL delipidation rate (P < 0.005). Catabolism of LDL was also lower in diabetic patients (P < 0.05). Atorvastatin treatment significantly decreased plasma triglycerides (P < 0.05), total and LDL cholesterol (P < 0.05), apoB100 in LDL, IDL, and VLDL (P < 0.05). Treatment significantly decreased total apoB100 production rate (P < 0.05), but only for VLDL (P < 0.05). Treatment normalized FCR in IDL and LDL (P < 0.05). We concluded that atorvastatin improved lipid abnormalities in type-2 diabetic patients not only by increasing the clearance of apoB100-containing lipoproteins but also by decreasing VLDL production.

Differential effects of amlodipine and atorvastatin treatment and their combination on atherosclerosis in ApoE*3-Leiden transgenic mice

This study was designed to investigate the potential antiatherosclerotic effects of the calcium antagonist amlodipine as compared with the HMG-CoA reductase inhibitor atorvastatin and the combination of both in ApoE*3-Leiden transgenic mice. Four groups of 15 ApoE*3-Leiden mice were put on a high-cholesterol diet. One group received 0.002% (wt/wt) amlodipine in the diet, which had no effect on plasma cholesterol levels. Another group received 0.01% (wt/wt) atorvastatin, resulting in a decrease of plasma cholesterol by 50% by a reduction in very low density lipoprotein production. The combination group received both amlodipine and atorvastatin. After 28 weeks, atherosclerosis in the aortic root was quantified. Treatment with amlodipine had no significant effect on atherosclerotic lesion area, whereas atorvastatin markedly reduced atherosclerosis by 77% compared with the control group. Atorvastatin also reduced inflammation markers. The combination of amlodipine and atorvastatin tended to reduce lesion area by 61% compared with the atorvastatin-only group; however, this effect did not reach statistical significance. Amlodipine treatment significantly reduced calcification in the lesions, whereas atorvastatin alone had no effect. The combination of amlodipine and atorvastatin resulted in a near absence of calcium deposits in the lesions. This study demonstrates that amlodipine treatment alone does not significantly reduce atherosclerotic lesion development. Atorvastatin was shown to have strong antiatherosclerotic effects, and cotreatment with amlodipine may potentiate the antiatherosclerotic effect of atorvastatin.

Effect of atorvastatin on postprandial lipoprotein metabolism in hypertriglyceridemic patients

Postprandial lipoprotein metabolism is impaired in hypertriglyceridemia. It is unknown how and to what extent atorvastatin affects postprandial lipoprotein metabolism in hypertriglyceridemic patients. We evaluated the effect of 4 weeks of atorvastatin therapy (10 mg/day) on postprandial lipoprotein metabolism in 10 hypertriglyceridemic patients (age, 40 +/- 3 years; body mass index, 27 +/- 1 kg/m2; cholesterol, 5.74 +/- 0.34 mmol/l; triglycerides, 3.90 +/- 0.66 mmol/l; HDL-cholesterol, 0.85 +/- 0.05 mmol/l; and LDL-cholesterol, 3.18 +/- 0.23 mmol/l). Patients were randomized to be studied with or without atorvastatin therapy. Postprandial lipoprotein metabolism was evaluated with a standardized oral fat load. Plasma was obtained every 2 h for 14 h. Large triglyceride-rich lipoproteins (TRLs) (containing chylomicrons) and small TRLs (containing chylomicron remnants) were isolated by ultracentrifugation, and cholesterol, triglyceride, apolipoprotein B-100 (apoB-100), apoB-48, apoC-III, and retinyl-palmitate concentrations were determined. Atorvastatin significantly (P < 0.01) decreased fasting cholesterol (-27%), triglycerides (-43%), LDL-cholesterol (-28%), and apoB-100 (-31%), and increased HDL-cholesterol (+19%). Incremental area under the curve (AUC) significantly (P < 0.05) decreased for large TRL-cholesterol, -triglycerides, and -retinyl-palmitate, while none of the small TRL parameters changed. These findings contrast with the results in normolipidemic subjects, in which atorvastatin decreased the AUC for chylomicron remnants (small TRLs) but not for chylomicrons (large TRLs). We conclude that atorvastatin improves postprandial lipoprotein metabolism in addition to decreasing fasting lipid levels in hypertriglyceridemia. Such changes would be expected to improve the atherogenic profile.

Atorvastatin markedly improves type III hyperlipoproteinemia in association with reduction of both exogenous and endogenous apolipoprotein B-containing lipoproteins

Remnant lipoproteins are known to promote atherosclerosis especially in patients with type III hyperlipoproteinemia (HLP). In the current study, the effects of atorvastatin were investigated with special reference to the exogenous and endogenous apolipoprotein (apo) B-containing lipoprotein metabolism in type III HLP. Four Japanese male patients with type III HLP associated with homozygous apoE2 were studied. One-month administration of atorvastatin (20 mg once daily), after a 4-week dietary run-in, strikingly reduced serum total cholesterol and triglyceride (TG) levels by 52 (P<0.01) and 56% (P<0.05), respectively. Atorvastatin further decreased remnant-like particle (RLP)-cholesterol by 73% and RLP-TG by 65% (P<0.05), respectively. Distribution analysis by polyacrylamide gel disc electrophoresis clearly showed that atorvastatin diminished very low-, intermediate- and low-density lipoprotein particles. The relative particle diameter of intermediate-density lipoprotein became smaller after atorvastatin treatment (P<0.01). Furthermore, ultracentrifugal analysis demonstrated that atorvastatin significantly decreased cholesterol, TG and phospholipid concentrations in all apoB-containing lipoprotein fractions and very low-density lipoprotein (VLDL)-cholesterol/serum TG ratio (P<0.05), implying atorvastatin-induced reduction of beta-VLDL. Finally, newly developed assays of apoB-48 and apoB-100 revealed that atorvastatin markedly reduced these apolipoproteins by 43 and 52%, respectively (P<0.01), suggesting that atorvastatin decreased the number of both exogenous and endogenous apoB-containing lipoproteins. Taken together, atorvastatin improves remnant lipoprotein metabolism in type III HLP both in quality and in quantity. Atorvastatin can be one of the optimal options for the treatment of patients with type III HLP.

Inhibition of both the apical sodium-dependent bile acid transporter and HMG-CoA reductase markedly enhances the clearance of LDL apoB

Discovery of the ileal apical sodium-dependent bile acid transporter (ASBT) permitted development of specific inhibitors of bile acid reabsorption, potentially a new class of cholesterol-lowering agents. In the present study, we tested the hypothesis that combining the novel ASBT inhibitor, SC-435, with the HMG-CoA reductase inhibitor, atorvastatin, would potentiate reductions in LDL cholesterol (LDL-C) and LDL apolipoprotein B (apoB). ApoB kinetic studies were performed in miniature pigs fed a typical human diet and treated with the combination of SC-435 (5 mg/kg/day) plus atorvastatin (3 mg/kg/day) (SC-435+A) or a placebo. SC-435+A decreased plasma total cholesterol by 23% and LDL-C by 40%. Multicompartmental analysis (SAAM II) demonstrated that LDL apoB significantly decreased by 35% due primarily to a 45% increase in the LDL apoB fractional catabolic rate (FCR). SC-435+A significantly decreased hepatic concentrations of free cholesterol and cholesteryl ester, and increased hepatic LDL receptor mRNA consequent to increased cholesterol 7alpha-hydroxylase expression and activity. In comparison, SC-435 (10 mg/kg/day) monotherapy decreased LDL apoB by 10% due entirely to an 18% increase in LDL apoB FCR, whereas atorvastatin monotherapy (3 mg/kg/day) decreased LDL apoB by 30% due primarily to a 22% reduction in LDL apoB production. We conclude that SC-435+A potentiates the reduction of LDL-C and LDL apoB due to complementary mechanisms of action.

Effect of atorvastatin on lipid parameters, LDL subtype distribution, hemorrheological parameters and adhesion molecule concentrations in patients with hypertriglyceridemia

BACKGROUND AND AIM

Hypertriglyceridemia is a risk factor for atherosclerosis that is typically associated with high concentrations of adhesion molecules, impaired hemorrheology and an unfavourable low-density lipoprotein (LDL) subtype distribution. We hypothesised that some of these risk markers might be beneficially influenced by lipid-lowering therapy with atorvastatin in hypertriglyceridemic patients.

METHODS AND RESULTS

Nineteen patents with primary hypertriglyceridemia were given 10 mg of atorvastatin per day for four weeks. Their cholesterol, triglyceride, LDL and high-density lipoprotein cholesterol (HDL-C) levels, LDL subtype profile, hemorrheological parameters and E-selectin, vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 concentrations were measured before and at the end of atorvastatin therapy. The levels of total and LDL cholesterol respectively decreased by 25% and 24% (both p < 0.001). Furthermore, cholesterol was reduced by 8-29% in all seven LDL subfractions (density range: 1.020-1.066 g/mL) (p < 0.05). The reduction in triglyceride concentrations was of marginal significance (9%, p = 0.1), but its degree positively correlated with the reduction of small-dense LDL (r = 0.5, p < 0.025). Plasma viscosity and blood viscosity at low shear rates were respectively reduced by 2% and 16% (both p < 0.05). The effect of the treatment on the concentrations of HDL-C, fibrinogen and adhesion molecules was not significant.

CONCLUSIONS

Atorvastatin (10 mg/day) not only reduced the plasma concentrations of atherogenic lipoproteins but also improved the LDL-subtype profile and reduced plasma and blood viscosity in patients with hypertriglyceridemia; however, it failed to significantly lower triglyceride concentrations.

Red wine polyphenolics increase LDL receptor expression and activity and suppress the secretion of ApoB100 from human HepG2 cells

Epidemiologic studies suggest that the consumption of red wine may lower the risk of cardiovascular disease. The cardioprotective effect of red wine has been attributed to the polyphenols present in red wine, particularly resveratrol (a stilbene, with estrogen-like activity), and the flavonoids, catechin, epicatechin, quercetin and phenolic acids such as gallic acid. At present, very little is known about the mechanisms by which red wine phenolic compounds benefit the cardiovascular system. Therefore, the aim of this study was to elucidate whether red wine polyphenolics reduce lipoprotein production and clearance by the liver. Cultured HepG2 cells were incubated in the presence of dealcoholized red wine, alcohol-containing red wine and atorvastatin for 24 h. The apolipoprotien B100 (apoB100) protein (marker of hepatic lipoproteins) was quantified on Western blots with an anti-apoB100 antibody and the enhanced chemiluminescence detection system. Apolipoprotein B100 levels in the cells and that secreted into the media were significantly reduced by 50% in liver cells incubated with alcohol-stripped red wine compared with control cells. This effect of dealcoholized red wine on apoB100 production in HepG2 cells was similar to the effect of atorvastatin. Apo B100 production was significantly attenuated by 30% in cells incubated with alcoholized red wine, suggesting that the alcohol was masking the effect of red wine polyphenolics. Apo B100 production was significantly attenuated by 45% with the polyphenolic compounds resveratrol and quercertin. In addition, dealcoholized and alcoholized red wine and atorvastatin significantly increased 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase mRNA and LDL receptor binding activity relative to controls. Dealcoholized red wine also increased LDL receptor gene expression. Collectively, this study suggests that red wine polyphenolics regulate major pathways involved in lipoprotein metabolism.

Atorvastatin improves metabolic control and endothelial function in type 2 diabetic patients: a placebo-controlled study

Several pieces of evidence support a role of inflammatory processes in the pathogenesis of atherosclerosis; it is also known that endothelial dysfunction is the initial lesion of the atherosclerotic process. Among other markers of endothelial dysfunction, some adhesion molecules seem to play an interesting role. The aim of the present study was to evaluate the effect of atorvastatin vs placebo on some indexes of leukocytes adhesion in a group of Type 2 diabetic patients. Twenty-five Type 2 diabetic patients free from microangiopathic complications and with LDL-cholesterol lower than 180 mg/dl were randomized to receive either atorvastatin (T2DA) or placebo (T2Dp) for twelve months. BMI, fasting plasma glucose, glycated hemoglobin (HbA1c), albumin excretion rate (AER), lipid profile, and serum concentrations of vascular cell adhesion molecule-1 (VCAM1), E-selectin and cadherin-5 were measured at baseline and at the end of the follow-up. At T0 E-selectin was 16 +/- 6 ng/ml in T2DA and 17 +/- 13 in T2Dp; VCAM1 was 413 +/- 112 ng/ml in T2DA and 411 +/- 112 in T2Dp. At T12 VCAM1 and E-selectin did not vary in T2Dp, while a significant reduction was observed in T2DA (VCAM1 275 +/- 104 ng/ml and E-selectin 8 +/- 3 ng/ml; p < 0.001 and p < 0.01, respectively). T2DA also showed a reduction of total and LDL cholesterol and an improved glycemic control respect to T2Dp. Hypolipidemic therapy was the strongest independent predictor of the cytokines variations along the time. These results confirm the role of statins in modulating endothelial function also in Type 2 diabetes, outlining a therapeutic role of these molecules probably independent from the hypolipidemic effect.

α-Heterosubstituted Aldehydes in Organic Synthesis. Enantioselective Approaches to New Analogues of Mevinic Acids

Various aldol approaches towards the asymmetric synthesis of the lactone moiety of HMG-CoA-reductase inhibitors are described. Auxiliary controlled as well as catalytic aldol reactions resulted only in modest to low selectivities, whereas 1,2-additions to readily available highly enantiomerically enriched α-heterosubstituted aldehydes yielded δ-hydroxy-β-ketoesters with a high degree of diastereocontrol and in good chemical yields. The novel mevinic acid analogues could then be obtained bysyn-reduction of the addition products.

The effect of Puerariae radix on lipoprotein metabolism in liver and intestinal cells

BACKGROUND

Animal studies investigating the beneficial effects of Puerariae radix on cardiovascular disease have suggested this plant possesses anti-diabetic and lipid lowering properties. However, the exact mechanism by which Puerariae radix affects lipid metabolism is currently unknown. The aim of this study was to investigate the effect of the water extract of Puerariae radix on the secretion of VLDL and chylomicrons from HepG2 liver cells and CaCo2 cells, respectively, in humans.

METHODS

The amount of apoB100 (a protein marker for VLDL) and apoB48 (a protein marker for chylomicrons) in cells and media were quantified by Western Blotting and enhanced chemiluminescence (ECL). Total, free and esterified cholesterol concentrations were measured by gas liquid chromatography.

RESULTS

Treatment of cells with water extract of Puerariae radix significantly decreased apoB100 production and secretion from HepG2 cells up to 66% in a dose dependent manner. The intracellular total cholesterol and free cholesterol concentration in HepG2 cells also decreased with increasing concentration of the Puerariae radix. In contrast, water extract of Puerariae radix attenuated apoB48 concentrations in cells, but not apoB48 secretion from CaCo2 enterocytes.

CONCLUSIONS

Collectively, our findings suggest that the water extract of Puerariae radix attenuates the hepatic lipoprotein production and secretion. Our present cell culture findings may explain why circulating VLDL and LDL levels were attenuated in animals supplemented with Puerariae radix. Since decreasing the production and secretion of atherogenic lipoproteins decreases the risk of development of cardiovascular disease, diets supplemented with radix may provide a safe and effective beneficial cardioprotective effects in humans.

Long term efficacy and safety of atorvastatin in the treatment of severe type III and combined dyslipidaemia

BACKGROUND

Fibric acid derivatives and HMG-CoA reductase inhibitors are effective in combination for treating patients with familial dysbetalipoproteinaemia and severe combined dyslipidaemia, but combination therapy affects compliance and increases the risk of side effects.

AIM

To evaluate the efficacy and safety of monotherapy with atorvastatin, an HMG-CoA reductase inhibitor with superior efficacy in lowering low density lipoprotein cholesterol and triglyceride concentrations, in patients with dysbetalipoproteinaemia and severe combined dyslipidaemia.

METHODS

Atorvastatin was tested as single drug treatment in 36 patients with familial dysbetalipoproteinaemia and 23 patients with severe combined dyslipidaemia.

RESULTS

After 40 weeks of 40 mg atorvastatin treatment decreases in total cholesterol, triglycerides, and apolipoprotein B of 40%, 43%, and 41%, respectively, were observed in the combined dyslipidaemia group, and of 46%, 40%, and 43% in the dysbetalipoproteinaemic patients. Target concentrations of total cholesterol (< 5 mmol/l) were reached by 63% of the patients, and target concentrations of triglycerides (< 3.0 mmol/l) by 66%. Treatment with atorvastatin was well tolerated and no serious side effects were reported.

CONCLUSIONS

Atorvastatin is very effective as monotherapy in the treatment of familial dysbetalipoproteinaemia and severe combined dyslipidaemia.

Influence of atorvastatin and simvastatin on apolipoprotein B metabolism in moderate combined hyperlipidemic subjects with low VLDL and LDL fractional clearance rates

Subjects with moderate combined hyperlipidemia (n=11) were assessed in an investigation of the effects of atorvastatin and simvastatin (both 40 mg per day) on apolipoprotein B (apoB) metabolism. The objective of the study was to examine the mechanism by which statins lower plasma triglyceride levels. Patients were studied on three occasions, in the basal state, after 8 weeks on atorvastatin or simvastatin and then again on the alternate treatment. Atorvastatin produced significantly greater reductions than simvastatin in low density lipoprotein (LDL) cholesterol (49.7 vs. 44.1% decrease on simvastatin) and plasma triglyceride (46.4 vs. 39.4% decrease on simvastatin). ApoB metabolism was followed using a tracer of deuterated leucine. Both drugs stimulated direct catabolism of large very low density lipoprotein (VLDL(1)) apoB (4.52+/-3.06 pools per day on atorvastatin; 5.48+/-4.76 pools per day on simvastatin versus 2.26+/-1.65 pools per day at baseline (both P<0.05)) and this was the basis of the 50% reduction in plasma VLDL(1) concentration; apoB production in this fraction was not significantly altered. On atorvastatin and simvastatin the fractional transfer rates (FTR) of VLDL(1) to VLDL(2) and of VLDL(2) to intermediate density lipoprotein (IDL) were increased significantly, in the latter instance nearly twofold. IDL apoB direct catabolism rose from 0.54+/-0.30 pools per day at baseline to 1.17+/-0.87 pools per day on atorvastatin and to 0.95+/-0.43 pools per day on simvastatin (both P<0.05). Similarly the fractional transfer rate for IDL to LDL conversion was enhanced 58-84% by statin treatment (P<0.01) LDL apoB fractional catabolic rate (FCR) which was low at baseline in these subjects (0.22+/-0.04 pools per day) increased to 0.44+/-0.11 pools per day on atorvastatin and 0.38+/-0.11 pools per day on simvastatin (both P<0.01). ApoB-containing lipoproteins were more triglyceride-rich and contained less free cholesterol and cholesteryl ester on statin therapy. Further, patients on both treatments showed marked decreases in all LDL subfractions. In particular the concentration of small dense LDL (LDL-III) fell 64% on atorvastatin and 45% on simvastatin. We conclude that in patients with moderate combined hyperlipidemia who initially have a low FCR for VLDL and LDL apoB, the principal action of atorvastatin and simvastatin is to stimulate receptor-mediated catabolism across the spectrum of apoB-containing lipoproteins. This leads to a substantial, and approximately equivalent, percentage reduction in plasma triglyceride and LDL cholesterol.

Atorvastatin and micronized fenofibrate alone and in combination in type 2 diabetes with combined hyperlipidemia

OBJECTIVE

This study evaluated the effect of a atorvastatin-fenofibrate combination on lipid profile, in comparison to each drug alone, in patients with type 2 diabetes and combined hyperlipidemia (CHL).

RESEARCH DESIGN AND METHODS

A total of 120 consecutive patients, who were free of coronary artery disease (CAD) at entry, were studied for a period of 24 weeks. These patients were randomly assigned to atorvastatin (20 mg/day, n = 40), micronized fenofibrate (200 mg/day, n = 40), or a combination of both (atorvastatin 20 mg/day plus fenofibrate 200 mg/day, n = 40). The effect of treatment on LDL cholesterol, triglycerides (TGs), HDL cholesterol, apolipoprotein A-I and B, lipoprotein(a), and plasma fibrinogen (PF) was recorded. Moreover, the percentage of patients that reached the American Diabetes Association treatment goals and the estimated CAD risk status were calculated.

RESULTS

No patient was withdrawn from the study because of side effects. The atorvastatin-fenofibrate combination reduced total cholesterol by 37%, LDL cholesterol by 46%, TGs by 50%, and PF by 20%, whereas it increased HDL cholesterol by 22% (P < 0.0001 for all). These changes were significantly better than those of both monotherapies. Of the patients on drug combination, 97.5% reached the LDL cholesterol treatment goal of <100 mg/dl, 100% reached the desirable TG levels of <200 mg/dl, and 60% reached the optimal HDL cholesterol levels of >45 mg/dl. These rates were significantly higher than those of both monotherapies. Combined treatment reduced the 10-year probability for myocardial infarction from 21.6 to 4.2%.

CONCLUSIONS

The atorvastatin-fenofibrate combination has a highly beneficial effect on all lipid parameters and PF in patients with type 2 diabetes and CHL. It improved patients' CAD risk status significantly more than each drug alone.

Effects of atorvastatin on postprandial plasma lipoproteins in postinfarction patients with combined hyperlipidaemia

Enhanced and prolonged postprandial lipaemia is implicated in coronary and carotid artery disease. This study assessed the effects of atorvastatin, a 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor, on postprandial plasma concentrations of triglyceride-rich lipoproteins (TRLs). Sixteen middle-aged men with combined hyperlipidaemia (baseline low density lipoprotein (LDL) cholesterol and plasma triglyceride concentrations (median (interquartile range) of 4.54 (4.17-5.26)) and 2.66 (2.04-3.20) mmol/l, respectively) and previous myocardial infarction were randomised to atorvastatin 40 mg or placebo once daily for 8 weeks in a double-blind, cross-over design. The apolipoprotein (apo) B-48 and B-100 contents were determined in subfractions of TRLs as a measure of chylomicron remnant and very low density lipoprotein (VLDL) particle concentrations (expressed as mg apo B-48 or apo B-100 per litre of plasma), in the fasting state and after intake of a mixed meal. Atorvastatin treatment reduced significantly the fasting plasma concentrations of VLDL cholesterol, LDL cholesterol and VLDL triglycerides (median% change) by 29, 44 and 27%, respectively, and increased high density lipoprotein (HDL) cholesterol by 19%, compared with baseline. The postprandial plasma concentrations of large (Svedberg flotation rate (Sf) 60-400) and small (Sf 20-60) VLDLs and chylomicron remnants were almost halved compared with baseline (mean 0-6 h plasma concentrations were reduced by 48% for Sf 60-400 apo B-100, by 46% for Sf 60-400 apo B-48, by 46% for Sf 20-60 apo B-100 and by 27% for Sf 20-60 apo B-48), and the postprandial triglyceridaemia was reduced by 23% during active treatment. In conclusion, atorvastatin 40 mg once daily causes profound reductions of postprandial plasma concentrations of all TRLs in combined hyperlipidaemic patients with premature coronary artery disease.

Apolipoprotein B metabolism: tracer kinetics, models, and metabolic studies

The study of apolipoprotein (apo) B metabolism is central to our understanding of lipoprotein metabolism. However, the assembly and secretion of apoB-containing lipoproteins is a complex process. Specialized techniques, developed and applied to in vitro and in vivo studies of apoB metabolism, have provided insights into the mechanisms involved in the regulation of this process. Moreover, these studies have important implications for understanding both the pathophysiology as well as the therapeutic options for the dyslipidemias. The purpose of this review is to examine the role of apoB in lipoprotein metabolism and to explore the applications of kinetic analysis and multicompartmental modeling to the study of apoB metabolism. New developments and significant advances over the last decade are discussed.

Cholesterol esters regulate apoB48 secretion in CaCo2 cells

In this study, we investigated the effect of atorvastatin, an HMG-CoA reductase inhibitor and CL277082, an ACAT inhibitor, on apolipoprotein B48 synthesis, degradation and secretion in transformed human intestinal enterocytes (CaCo2 cells). Cells were incubated with atorvastatin or CL277082 in the absence or presence of sterol containing media and pulsed with [S35]-methionine and chased with unlabelled methionine. Concomitantly, the effect of atorvastatin and CL277082 on the relative amount of apoB48 protein in cells and media was also quantified by western blotting using an apoB antibody and enhanced chemiluminescence. Suppression of cholesterol synthesis with atorvastatin did not attenuate the production or secretion of apoB48 from CaCo2 cells under basal conditions. On the other hand, suppression of cholesterol biosynthesis with atorvastatin under stimulatory conditions accelerated the degradation of apoB48 in cells without affecting its synthesis or secretion. There was no effect of exogenous sterols on apoB48 secretion. Taken together, neither endogenous nor exogenous cholesterol appears to acutely modulate apoB48 secretion from intestinal cells. In contrast, inhibition of cholesterol esterification with ACAT inhibitor significantly attenuated apoB48 secretion under basal and stimulatory conditions by a mechanism which enhanced apoB48 degradation. Collectively, our results suggest that in CaCo2 cells, newly synthesized cholesterol ester may be an immediate regulator apoB48 secretion.

Effect of atorvastatin, simvastatin, and lovastatin on the metabolism of cholesterol and triacylglycerides in HepG2 cells

We evaluated the effects of the hydroxymethylglutaryl coenzyme A reductase inhibitors (HMGRI) atorvastatin, lovastatin, and simvastatin on lipid homeostasis in HepG2 cells. The drugs were almost equally effective in inhibiting cholesterol synthesis and in decreasing cellular cholesterol. Atorvastatin and lovastatin increased low-density lipoprotein receptor mRNA (2.5-fold at 3 x 10(-7) M) and the transcription rate at the promoter of the low-density lipoprotein receptor gene (>5-fold at 10(-6) M). The three compounds enhanced the activity of the low-density lipoprotein receptor at a similar magnitude (1.6-2.1- fold at 10(-6) M). Atorvastatin and lovastatin increased the nuclear form of sterol regulatory element binding protein (SREBP)-2, but not of SREBP-1. Each of the drugs increased triacylglyceride synthesis (50% at 10(-7)-10(-6) M), cellular triacylglyceride content (16% at 10(-6) M), and expression of fatty acid synthase by reporter gene and Northern blot analysis (2-fold and 2.7-fold at 10(-6) M and 3 x 10(-7) M, respectively). All compounds reduced the secretion of apo B (30% at 3 x 10(-7) M). HMGRI decreased the ratio of cholesterol to apo B in newly synthesised apo B containing particles by approximately 50% and increased the ratio of triacylglycerides to apo B by approximately 35%. We conclude that regulatory responses to HMGRI are mediated by SREBP-2 rather than by SREBP-1, that HMGRI oppositely affect the cellular cholesterol and triacylglyceride production, that HMGRI moderately decrease the release of apo B containing particles, but profoundly alter their composition, and that atorvastatin does not significantly differ from other HMGRI in these regards.

Effect of atorvastatin on intracellular calcium uptake in coronary smooth muscle cells from diabetic pigs fed an atherogenic diet

Intracellular Ca(2+) store loading has been shown to alter proliferation and apoptosis of several cell types. In addition, HMG-CoA reductase inhibitors (i.e. atorvastatin) are effective in treating diabetic dyslipidemic patients. Thus, we hypothesized that chronic atorvastatin treatment would prevent increased Ca(2+) uptake into intracellular Ca(2+) stores in vascular smooth muscle cells from diabetic dyslipidemic pigs. Male Yucatan pigs were divided into four groups for 20 weeks-- (1) low fat fed (control); (2) hyperlipidemic (F); (3) alloxan-induced diabetic dyslipidemic (DF); and (4) diabetic dyslipidemic pigs treated with atorvastatin (DFA). The F, DF, and DFA groups were fed a high fat/cholesterol diet. Cells were isolated from the coronary artery and the myoplasmic Ca(2+) (Ca(m)) response measured using single cell fura-2 imaging. The Ca(m) response to caffeine (5 mM to release Ca(2+) from the sarcoplasmic reticulum, SR) and ionomycin (10 microM; to release the total Ca(2+) store) was determined in either the presence of low Na (19Na; inhibits Na(+)-Ca(2+) exchange), thapsigargin (TSG; inhibits the SR Ca(2+) pump), and a 19Na+TSG solution. Low Na induced the uptake of Ca(2+) into both SR and non-SR Ca(2+) stores in the DF group, but not the DFA group. Furthermore, after depletion of the SR Ca(2+) store with TSG, 19Na evoked Ca(2+) uptake into non-SR Ca(2+) stores in all three groups except in the DFA group. In summary, this study demonstrates that atorvastatin prevents the enhanced uptake of Ca(2+) by SR and non-SR Ca(2+) stores in diabetic dyslipidemic pigs.

Prolonged inhibition of cholesterol synthesis by atorvastatin inhibits apo B-100 and triglyceride secretion from HepG2 cells

Atorvastatin is a new HMG-CoA reductase inhibitor that strongly lowers plasma cholesterol and triglyceride (TG) levels in humans and animals. Since previous data indicated that atorvastatin has prolonged inhibition of hepatic cholesterol synthesis, we tested whether this longer duration of inhibitory effect on cholesterol synthesis decreased hepatic lipoprotein secretion in vitro. We used the HepG2 hepatoma cell line to: (1) determine the time required until levels of secreted apo B-100 and TG declined significantly, (2) examine the relation to the mass of cellular cholesteryl ester (CE) and (3) test microsomal triglyceride transfer protein (MTP) activity which leads to decreased apo B-100 production. Although atorvastatin significantly inhibited cholesterol synthesis in HepG2 cells regardless of treatment duration (1, 14 or 24 h), it did not inhibit TG synthesis. Apo B-100 and TG secretion were unchanged after 1-h atorvastatin treatment, but declined significantly after 24-h treatment. Atorvastatin treatment also reduced cellular CE mass, exhibiting both time- and dose-dependency. Mevalonolactone, a product of HMG-CoA reductase, attenuated the inhibitory effects of atorvastatin. Atorvastatin strongly reduced mRNA levels of MTP, whereas it did not inhibit MTP activity as measured by TG transfer assay between liposomes. Simvastatin also induced treatment- and time-dependent reductions in apo B-100, whereas the MTP inhibitor BMS-201038 exhibited no time dependency, instead inhibiting this variable even on 1-h treatment. These results indicate that reduced apo B-100 secretion caused by atorvastatin is a secondary result owing to decreased lipid availability, and that atorvastatin's efficacy depends on the duration of cholesterol synthesis inhibition in the liver.

Effects of atorvastatin versus fenofibrate on lipoprotein profiles, low-density lipoprotein subfraction distribution, and hemorheologic parameters in type 2 diabetes mellitus with mixed hyperlipoproteinemia

Diabetic dyslipoproteinemia characterized by hypertriglyceridemia, low high-density lipoprotein (HDL) cholesterol, and often elevated low-density lipoprotein (LDL) cholesterol with predominance of small, dense LDL is a strong risk factor for atherosclerosis. It is unclear whether fibrate or statin therapy is more effective in these patients. We compared atorvastatin (10 mg/day) with fenofibrate (200 mg/day), each for 6 weeks separated by a 6-week washout period in 13 patients (5 men and 8 women; mean age 60.0+/-6.8 years; body mass index 30.0+/-3.0 kg/m2) with type 2 diabetes mellitus (hemoglobin A1c 7.3+/-1.1%) and mixed hyperlipoproteinemia (LDL cholesterol 164.0+/-37.8 mg/dl, triglycerides 259.7+/-107 mg/dl, HDL cholesterol 48.7+/-11.0 mg/dl) using a randomized, crossover design. Lipid profiles, LDL subfraction distribution, fasting plasma viscosity, red cell aggregation, and fibrinogen concentrations were determined before and after each drug. Atorvastatin decreased all LDL subfractions (LDL cholesterol, -29%; p <0.01) including small, dense LDL. Fenofibrate predominantly decreased triglyceride concentrations (triglycerides, -39%; p <0.005) and induced a shift in LDL subtype distribution from small, dense LDL (-31%) to intermediate-dense LDL (+36%). The concentration of small, dense LDL was comparable during therapy to both drugs (atorvastatin 62.8+/-19.5 mg/dl, fenofibrate 63.0+/-18.1 mg/dl). Both drugs induced an increase in HDL cholesterol (atorvastatin +10%, p <0.05; fenofibrate +11%, p = 0.06). In addition, fenofibrate decreased fibrinogen concentration (-15%, p <0.01) associated with a decrease in plasma viscosity by 3% (p <0.01) and improved red cell aggregation by 15% (p <0.05), whereas atorvastatin did not affect any hemorheologic parameter. We conclude that atorvastatin and fenofibrate can improve lipoprotein metabolism in type 2 diabetes. However, the medications affect different aspects of lipoprotein metabolism.

[Atorvastatin (Lipitor): a review of its pharmacological and clinical profile]

Hypercholesterolemia is a major risk factor for the development of coronary heart disease. HMG-CoA reductase inhibitors have been used as first-line drugs because of both their superior cholesterol lowering effect and reliable safety profile. Since there are many patients whose plasma cholesterol level does not reach the therapeutic target even if reductase inhibitors are available, more effective drugs have been strongly required for a long time. Atorvastatin, one of the most recently introduced statins, produces greater plasma LDL-cholesterol reductions than other statins. This pronounced effect of atorvastatin seems to be due to its long-lasting action, presumably a reflection of longer residence time of atorvastatin and its active metabolites in the liver. Clinical trials of atorvastatin have also demonstrated marked plasma triglyceride reductions. The triglyceride reduction with atorvastatin seems to stem from the following two indirect mechanisms, limiting VLDL secretion from the liver and increase in clearance of triglyceride-rich lipoprotein via induced LDL receptors from plasma. Eleven clinical trials of atorvastatin, which have been developed in Japan, clearly demonstrated its ability to reduce LDL-C levels more strongly and in significantly more patients to LDL-C treatment goals than other reductase inhibitors with similar safety profiles. Therefore, atorvastatin adds a new dimension to the effective management of hypercholesterolemia and combined hyperlipidemia.

Short- and long-term effects of atorvastatin, lovastatin and simvastatin on the cellular metabolism of cholesteryl esters and VLDL secretion in rat hepatocytes

The short- and long-term in vitro effects of the hydroxymethylglutaryl-CoA reductase inhibitor atorvastatin, compared with lovastatin and simvastatin on VLDL secretion, and on the formation and the neutral and acid lysosomal hydrolysis of cholesteryl esters was investigated in rat liver hepatocytes maintained in suspension (2 or 4 h) or cultured in monolayers (24 h). All statins time-dependently reduced [14C]oleate incorporation into cholesteryl esters, but when exogenous cholesterol was added only atorvastatin caused an immediate transient decrease in hepatocyte ACAT activity. Activity of the lysosomal, microsomal and cytosolic CEH isoforms was unaffected by the hepatocyte treatments. Statins reduced free and esterified cholesterol mass in hepatocyte microsomes after 2 h, and this was followed by a modest decline in VLDL cholesteryl esters, whilst secretion of VLDL apoB and triglycerides was unaltered. However, after 24 h of treatment, statins caused generalized 20-40% decreases in the secretion of VLDL apoB, cholesterol and triglycerides, with the reduction in apoB48 secretion being significantly superior to that caused in apoB100. The mean diameter of secreted VLDL was not modified by either duration or drug treatment. Additional studies with subcellular fractions demonstrated that statins have a direct selective effect on the enzymes governing the cholesterol-cholesteryl ester cycle, with the exception of the microsomal CEH. Atorvastatin, lovastatin and simvastatin inhibited ACAT activity in microsomes by 50% at doses of 250, 100 and 50 microM, respectively. The cytosolic CEH elicited a biphasic profile of activity with activations up to 100 microM statin and inhibitions above 250 microM, and the lysosomal CEH was only inhibited by atorvastatin at a dose of 100 microM or more. We conclude that a prolonged, but not a short, limited availability of hepatocyte cholesterol derived from the endogenous synthesis reduces VLDL secretion, and that reactivity of statins at the cellular level are more similar than reactivity at the subcellular level as regards the cholesterol-cholesteryl ester cycle.

Atorvastatin improves postprandial lipoprotein metabolism in normolipidemlic subjects

Atorvastatin is a potent HMG-CoA reductase inhibitor that decreases low-density lipoprotein (LDL) cholesterol and fasting triglyceride concentrations. Because of the positive association between elevated postprandial lipoproteins and atherosclerosis, we investigated the effect of atorvastatin on postprandial lipoprotein metabolism. The effect of 4 weeks of atorvastatin therapy (10 mg/day) was evaluated in 10 normolipidemic men (30+/-2 yr; body mass index, 22+/-3 kg/m2; cholesterol, 4.84+/-0.54 mmol/L; triglyceride, 1.47+/-0.50 mmol/L; high-density lipoprotein cholesterol, 1.17+/-0.18 mmol/L; LDL-cholesterol, 3.00+/-0.49 mmol/L). Postprandial lipoprotein metabolism was evaluated with a standardized fat load (1300 kcal, 87% fat, 7% carbohydrates, 6% protein, 80,000 IU vitamin A) given after 12 h fast. Plasma was obtained every 2 h for 14 h. A chylomicron (CM) and a chylomicron-remnant (CR) fraction was isolated by ultracentrifugation, and triglycerides, cholesterol, apolipoprotein B, apoB-48, and retinyl-palmitate were determined in plasma and in each lipoprotein fraction. Atorvastatin therapy significantly (P < 0.001) decreased fasting cholesterol (-28%), triglycerides (-30%), LDL-cholesterol (-41%), and apolipoprotein B (-39%), whereas high-density lipoprotein cholesterol increased (4%, not significant). The area under the curve for plasma triglycerides (-27%) and CR triglycerides (-40%), cholesterol (-49%), and apoB-48 (-43%) decreased significantly (P < 0.05), whereas CR retinyl-palmitate decreased (-34%) with borderline significance (P = 0.08). However, none of the CM parameters changed with atorvastatin therapy. This indicates that, in addition to improving fasting lipoprotein concentrations, atorvastatin improves postprandial lipoprotein metabolism presumably by increasing CR clearance or by decreasing the conversion of CMs to CRs, thus increasing the direct removal of CMs from plasma.

The effect of atorvastatin on serum lipids and lipoproteins in patients with homozyous familial hypercholesterolemia undergoing LDL-apheresis therapy

The efficacy of atorvastatin, a new hydroxymethylglutaryl (HMG)-CoA reductase inhibitor, in reducing serum lipid levels, modifying lipoprotein composition, and suppressing cholesterol synthesis was evaluated in patients with homozygous familial hypercholesterolemia (homozygous FH) undergoing LDL-apheresis therapy. Atorvastatin was given in escalating doses (10, 20, and 40 mg/day) to nine patients with homozygous FH. Five of nine patients responded well to atorvastatin; four of these patients were receptor-defective and the remaining one was receptor-negative. The change in LDL-cholesterol in the receptor-defective patients averaged -20.6% compared to the baseline level at the highest dose of atorvastatin. Of five receptor-negative type patients, only one showed good response to atorvastatin therapy with a LDL-cholesterol reduction of 14.9%. Although the other four receptor-negative patients did not show a change in LDL-cholesterol, all of them exhibited a considerable increase in HDL-cholesterol. All patients showed reduced urinary excretion of mevalonic acid, suggesting that atorvastatin decreases LDL-cholesterol by inhibiting cholesterol biosynthesis even where LDL-receptor activity is not present. Atorvastatin also decreased serum triglycerides in both receptor-negative and defective patients, especially in the latter. As cholesterol level rebounds quickly after each apheresis procedure, a combination therapy using atorvastatin and apheresis may increase the efficacy of the apheresis treatment, improving cost-benefit effectiveness by reducing the frequency of the apheresis treatment.

Enhanced secretion of ApoB by transfected HepG2 cells overexpressing fibrinogen

HepG2 cells stably transfected with cDNA-encoding single fibrinogen chains overexpress fibrinogen and have increased (4-fold) secretion of apolipoprotein B. Overexpression of fibrinogen does not affect the secretion of three representative acute-phase proteins but causes a small increase in albumin secretion. Enhanced apolipoprotein B secretion is due to less intracellular degradation and not to increased expression. The increased secretion of apolipoprotein B is independent of the acute-phase response, since stimulation of fibrinogen gene expression by interleukin 6 did not affect secretion. HepG2 cells overexpressing fibrinogen chains had increased 3-hydroxy-3-methylglutaryl coenzyme A reductase mRNA levels, enhanced cholesterol production but normal levels of triglyceride and phospholipid synthesis and of sterol response binding proteins. These results, that associate overexpression of fibrinogen with enhance apolipoprotein B secretion, may be significant since epidemiological studies indicate that elevated levels of fibrinogen and lipids are independent risk factors in coronary artery disease.