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PubMed1992

Free radicals mediate endothelial cell dysfunction caused by elevated glucose.

Impaired endothelium-dependent relaxation occurs in diabetic rabbit aorta and normal aorta exposed to elevated concentrations of glucose and is prevented by cyclooxygenase inhibitors. The role of free radicals in the endothelial cell impairment was examined with free radical scavengers and in aortas from rabbits fed with probucol (1% wt/wt, a lipid-soluble antioxidant). Rings of aorta suspended for measurement of isometric tension were incubated for 6 h in control (5.5 mM) or elevated (44 mM) glucose. Impairment of endothelium-dependent relaxation to acetylcholine caused by exposure to elevated glucose was prevented by superoxide dismutase, catalase, deferoxamine, or allopurinol and did not occur in aortas from probucol-fed rabbits. Similarly, impairment of acetylcholine relaxations in aortas from alloxan-induced diabetic rabbits was restored to normal by superoxide dismutase. Oxygen-derived free radicals generated by xanthine oxidase also caused impaired acetylcholine relaxations. Exposure of aortic segments to elevated glucose or to xanthine oxidase caused a significant increase in release of immunoreactive prostanoids. These data indicate that the endothelial cell dysfunction caused by elevated glucose is mediated by free radicals that are likely generated through the increased cyclooxygenase catalysis occurring in the endothelium. Treatment with antioxidants protects against impaired endothelium-dependent relaxations caused by elevated glucose.

Animals↗
PubMed2006

Relative contributions of ABCA1 and SR-BI to cholesterol efflux to serum from fibroblasts and macrophages.

OBJECTIVE: Cholesterol efflux is achieved by several mechanisms. This study examines contributions of these pathways to efflux to human serum. METHODS AND RESULTS: Human fibroblasts were stably transfected with SR-BI while ABCA1 was upregulated. Quantitation of cholesterol efflux to human serum demonstrated that there was efflux from cells without either protein. Expression of ABCA1 produced a small increase in efflux, whereas SR-BI expression had a dramatic impact. To quantitate ABCA1 and SR-BI contribution, fibroblasts were pretreated with Probucol and BLT-1 to, respectively, inhibit these efflux proteins. Exposing SR-BI-expressing fibroblasts to BLT-1 inhibited efflux by 67%. Probucol pretreatment of ABCA1-expressing fibroblasts reduced efflux to serum by 26%. A large fraction of total efflux was uninhibited. For both J774 and mouse peritoneal macrophages, contributions of either ABCA1 or SR-BI to efflux to serum were low, with background/uninhibited efflux contributing from 70% to 90% of total efflux. CONCLUSIONS: We have shown that ABCA1-mediated efflux to serum responds to the pool of lipid-free/poor apolipoproteins, whereas phospholipid-containing particles mediate SR-BI efflux. Although SR-BI and ABCA1 contribute to efflux from fibroblasts and cholesterol-enriched macrophages, a large proportion of the total efflux to human serum is mediated by a mechanism that is neither SR-BI nor ABCA1.

ATP Binding Cassette Transporter 1↗
PubMed1994

Proteinuria in passive Heymann nephritis is associated with lipid peroxidation and formation of adducts on type IV collagen.

Passive Heymann nephritis (PHN) is a model of human membranous nephropathy that is characterized by formation of granular subepithelial immune deposits in the glomerular capillary wall which results in complement activation. This is causally related to damage of the filtration barrier and subsequent proteinuria. The local accumulation of injurious reactive oxygen species (ROS) is a major effector mechanism in PHN. ROS may induce tissue damage by initiating lipid peroxidation (LPO). In turn, this leads to adduct formation between breakdown products of LPO with structural proteins, such as formation of malondialdehyde (MDA) or 4-hydroxynonenal-lysine adducts. To examine the role of LPO in the development of proteinuria we have localized MDA and 4-hydroxynonenal-lysine adducts in glomeruli of PHN rats by immunofluorescence microscopy, using specific monoclonal antibodies. By immunogold electron microscopy, MDA adducts were localized to cytoplasmic vesicles and cell membranes of glomerular epithelial cells, to the glomerular basement membrane (GBM), and also to immune deposits. Type IV collagen was specifically identified as being modified by MDA adducts, using a variety of techniques. Collagenase pretreatment of GBM extracts indicated that the NC-1 domain of type IV collagen was a site of adduct formation. When LPO was inhibited by pretreatment of PHN rats with the antioxidant probucol, proteinuria was reduced by approximately 85%, and glomerular immunostaining for dialdehyde adducts was markedly reduced, even though the formation of immune deposits was not affected. By contrast, lowering of the serum cholesterol levels had no influence on the development of proteinuria. These findings are consistent with the premise that ROS-induced glomerular injury in PHN involves LPO and that this results not only in damage of cell membranes but in modification of type IV collagen in the GBM as well. The close temporal correlation of the occurrence of LPO with proteinuria and the ability of probucol to inhibit proteinuria support a causal role for LPO in the the alteration of the glomerular permselectivity which results in proteinuria.

Aldehydes↗
PubMed2003

Vascular protectants for the treatment of atherosclerosis.

AGI-1067, the monosuccinic acid ester of probucol, is a phenolic antioxidant member of a novel class of agents termed vascular protectants. It has strong antioxidant properties, equipotent to those of probucol, and anti-inflammatory properties. It inhibits gene expression of vascular cell adhesion molecule-1 and monocyte chemotactic protein-1 and has been effective at preventing atherosclerosis in all tested animal models. It also improved luminal dimensions of reference segments in the percutaneous coronary intervention (PCI) vessels in the CART-1 clinical trial, which suggests a direct anti-atherosclerosis effect. Two important trials that test the antioxidant/anti-inflammatory hypothesis are ongoing with AGI-1067: the Canadian Atherosclerosis and Restenosis Trial, which assesses its value for the reduction of both atherosclerosis progression in non-PCI vessels and post-PCI restenosis, and the Aggressive Reduction of Inflammation Stops Events trial, which is evaluating the effects of AGI-1067 on hard cardiovascular outcomes.

Antioxidants↗
PubMed2001

Effects of insulin and antioxidant on plasma 8-hydroxyguanine and tissue 8-hydroxydeoxyguanosine in streptozotocin-induced diabetic rats.

Cumulating evidence suggests that enhanced oxidative stress may contribute to diabetic angiopathy. The levels of 8-hydroxydeoxyguanosine (8-OHdG) and 8-hydroxyguanine (8-OHG), indicators of oxidative DNA damage, in tissue or body fluid are increased in diabetic patients. However, it is unclear whether plasma 8-OHG correlates with tissue 8-OHdG and whether insulin or antioxidant treatment reduces plasma 8-OHG in diabetic state. In this study, we measured the 8-OHG levels in plasma as well as the 8-OHdG levels in liver and kidney in streptozotocin-induced diabetic rats (DR) treated with insulin (DR+I), insulin and probucol (DR+I/P), or insulin and vitamin E (DR+I/E). There was a correlation between plasma 8-OHG levels and tissue 8-OHdG levels (plasma 8-OHG vs. liver 8-OHdG: r = 0.64, P < 0.001; plasma 8-OHG vs. kidney 8-OHdG: r = 0.38, P = 0.06). DR had levels of plasma 8-OHG that were three times higher than control rats (CR), whereas they had levels of tissue 8-OHdG that were approximately 1.5-2 times higher. Plasma 8-OHG levels in DR were almost normalized by insulin treatment, although insulin partially corrected hyperglycemia (plasma 8-OHG: CR 3.3 +/- 2.7 pmol/ml; DR 10.4 +/- 2.3 pmol/ml, P < 0.05 vs. CR; DR with insulin 3.6 +/- 1.0 pmol/ml, P < 0.05 vs. DR). However, tissue 8-OHdG levels in DR were significantly decreased by combined treatment with insulin and antioxidant (probucol or vitamin E), but not by insulin treatment alone. This data suggests that plasma 8-OHG could be a useful biomarker of oxidative DNA damage in diabetic subjects. The mechanism of differential response of plasma 8-OHG and tissue 8-OHdG to insulin and antioxidant treatment remains to be elucidated.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1999

Involvement of MCP-1 and M-CSF in glomerular foam cell formation in ExHC rats.

BACKGROUND: An increase in glomerular macrophages (MO) is considered a potential effector mechanism by which hypercholesterolemia exacerbates glomerular injury. To investigate the mechanism underlying recruitment of MO into glomeruli, the expression of glomerular monocyte chemoattractant protein-1 (MCP-1) and macrophage colony-stimulating factor (M-CSF) mRNA were examined using a lipid-induced glomerular injury rat model. METHODS: Eight-week-old male ExHC rats, a strain susceptible to hyperlipidemia, were divided into the following 4 groups: a control group (C), a high cholesterol diet group (HH), a high cholesterol diet/standard diet group (HN), which were fed a high cholesterol diet for the first 4 weeks and a standard diet for the following 4 weeks, and a probucol-treatment group (PT). Both MCP-1 and M-CSF mRNA expression in glomeruli were analyzed using the RT-PCR method. An additional experimental group (M) fed a high cholesterol diet was administered M-CSF daily for 4 weeks. RESULTS: The expression of MCP-1 mRNA in glomeruli increased accompanied by an increased total serum cholesterol level in HH and HN. However, M-CSF mRNA expression was significantly suppressed at 1 or 2 weeks and gradually increased to almost basal levels. In the PT group, MCP-1 mRNA expression was suppressed. The early suppression of M-CSF mRNA expression was inhibited in PT. Renal histology showed a significant increase in foam cells in glomeruli in HH and HN rats at 4 weeks. HH rats showed increased and expanded foam cells at 8 weeks. In HN rats, however, foam cells decreased significantly after the transfer to a standard diet from a high cholesterol diet. The MCP-1 mRNA expression was suppressed after the transfer. In the PT group, foam cell formation was also suppressed. Foam cells were identified as MO. M-CSF-treatment significantly suppressed foam cell formation in glomeruli when compared with the untreated group levels. CONCLUSION: These findings suggest that hypercholesterolemia stimulated the expression of MCP-1 in glomeruli and attracted the MO into glomeruli. They also suggest that the reduction of hypercholesterolemia after the change in diet or treatment with probucol suppressed glomerular injury by suppressing the glomerular MCP-1 expression. M-CSF may suppress the recruitment of MO into glomeruli and foam cell formation at an early stage of hypercholesterolemia-induced glomerular injury.

Animals↗
PubMed1999

Effect of virgin olive oil phenolic compounds on in vitro oxidation of human low density lipoproteins.

BACKGROUND AND AIM: Substantial evidence suggests that oxidative modifications of low density lipoproteins (LDL) critically contribute to the pathogenesis and progression of human atherosclerosis. Oxidized LDL (oxLDL) are present in atherosclerotic plaques and contain oxysterols that exhibit a variety of adverse biological activities. Antioxidants have also been shown to prevent LDL modification. We have therefore assessed the efficacy of virgin olive oil phenolic compounds in preventing oxidative modifications of human LDL oxidized by UV light. METHODS AND RESULTS: Cholesterol oxides formed during LDL photo-oxidation were determined by UV-HPLC in the presence of different concentrations of phenolic compounds and their pure components (tyrosol and oleuropein), and probucol, a widely used synthetic antioxidant. Electrophoretic mobility was also assayed. The results demonstrate that phenolic compounds are much more potent in preventing cholesterol oxide formation and apoproteic moiety modification than their pure components and probucol. CONCLUSIONS: The beneficial effects of a Mediterranean diet may be ascribable not only to the high unsaturated/saturated fatty acid ratio characteristic of olive oil, but also to the unique antioxidant properties of its phenolic compounds.

Anticholesteremic Agents↗
PubMed2006

Both hepatitis C virus and Chlamydia pneumoniae infection are related to the progression of carotid atherosclerosis in patients undergoing lipid lowering therapy.

Recent experimental and epidemiological findings suggest that infectious agents may play a role in the development and progression of atherosclerosis. We previously reported that Chlamydia pneumoniae (C. pneumoniae) infection reduces the effectiveness of lipid-lowering therapy for carotid atherosclerosis and that this micro-organism may play a role in the progression of atherosclerosis. In this study, we investigated the possible association between hepatitis C virus (HCV) infection and carotid arteriosclerosis. A total of 165 asymptomatic hypercholesterolemic patients were randomized to receive probucol (500 mg/day, n=82) or pravastatin (10 mg/day, n=83) and were followed for 2 years. The 2-year change of the maximum common carotid artery intima-media thickness (Max-IMT) was the primary endpoint, while the Max-IMT and the incidence of major cardiovascular events were secondary endpoint. All serum samples were tested for antibody to HCV (anti-HCV) by enzyme-linked immunosorbent assay (ELISA), and all anti-HCV-positive samples were assayed for HCV RNA. Patients without HCV infection (n=25) showed a significant reduction of Max-IMT (-10.9%) (p<0.0001), while a small decrease of Max-IMT was noted in the patients with HCV infection (n=25) (-0. 3%). Significant differences in the reduction of serum total cholesterol and LDL cholesterol were found between patients with and without HCV infection (both p<0.0001). No significant difference in therapeutic effect was noted between the probucol and the pravastatin groups. After adjustment for confounding risk factors, both C. pneumoniae infection and anti-HCV positivity were associated with a greater risk of an increase in Max-IMT (8.5635 [1.3738-15.7532], p<0.05, 9.5040 [0.2886-18.7194], p<0.05, respectively). These findings suggest that both chronic HCV infection and C. pneumoniae infection can reduce the effectiveness of lipid-lowering therapy for carotid atherosclerosis, and that the HCV may play a role in the progression of atherosclerosis in HCV infected patients.

Adult↗
PubMedDate not supplied

Treatment of heterozygous familial hypercholesterolemia with lipid-lowering drugs.

Patients with heterozygous familial hypercholesterolemia (FH) constitute a unique population at high risk for the premature development of coronary artery disease (CAD) and in whom long-term hypocholesterolemic therapy to reduce elevated levels of low density lipoprotein (LDL) cholesterol is most clearly indicated. Optimal therapy invariably requires diet regulation plus hypolipidemic drug therapy. When used as single agents, the bile-acid sequestrants, cholestyramine and colestipol, lower LDL cholesterol concentrations by 20% to 35% in compliant patients, whereas decreases of 20% to 30% can be achieved with nicotinic acid in doses of 3 to 6 g/day. Bezafibrate, fenofibrate, and ciprofibrate have also been shown to lower LDL cholesterol levels by 20% to 30%, and these drugs are more effective than gemfibrozil and clofibrate. Probucol, neomycin, and D-thyroxine reduce LDL cholesterol concentrations by 10% to 15% in single-drug use. Clinical trials with a new class of drugs that inhibit the rate-limiting enzyme in cholesterol biosynthesis, 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, and that includes lovastatin, simvastatin, and pravastatin indicate that these drugs lower LDL cholesterol concentrations by 30% to 50% in patients with heterozygous FH. Combined drug therapy with a bile-acid sequestrant and nicotinic acid lowers LDL cholesterol by 40% to 55%, whereas fenofibrate, bezafibrate, or probucol plus a bile-acid sequestrant results in reductions varying from 25% to 50%. The combinations of an HMG CoA reductase inhibitor with either a bile-acid sequestrant or nicotinic acid appears to be the most promising, and these regimens reduce LDL cholesterol levels by 45% to 60%. With appropriate use, the currently available hypocholesterolemic drugs have the potential to markedly change the natural history of premature atherosclerosis that occurs in untreated patients with FH.

Butyrates↗
PubMed1989

Antioxidant treatment of diabetic rats inhibits lipoprotein oxidation and cytotoxicity.

Increased lipid peroxidation products were detected in a lipoprotein fraction containing very low density lipoprotein (VLDL) and low density lipoprotein (LDL) obtained from rats made diabetic by streptozotocin injection. The enhanced oxidation in the diabetic VLDL plus LDL fraction correlated with the in vitro toxicity of this lipoprotein fraction to proliferating fibroblasts. In contrast, high density lipoprotein (HDL) was not cytotoxic. That the increased oxidation and development of cytotoxic activity in the diabetic VLDL + LDL was related to the diabetes was shown by the fact that insulin treatment of diabetic animals inhibited both oxidation and cytotoxicity of VLDL + LDL. In contrast, treatment of diabetic rats with the antioxidants vitamin E or probucol after diabetes was established also inhibited both the in vivo oxidation and in vitro cytotoxicity of diabetic VLDL + LDL, but without altering hyperglycemia. Vitamin E or probucol treatment thus allowed separation of the oxidation process from the hyperglycemia occurring in experimental diabetes. The mechanisms by which diabetes in humans or experimental animals leads to the various manifestations of tissue damage are unknown; however, these studies demonstrate for the first time that a relationship exists between the in vivo oxidation of lipoproteins in diabetes and the potential for tissue damage as monitored by in vitro cytotoxicity. Furthermore, these results suggest that the mechanism for certain aspects of tissue damage accompanying experimental diabetes may be mediated by lipid peroxidation products.

Animals↗
PubMed1985

[Hyperlipoproteinemia type III with apolipoprotein E phenotype 2/2].

A 47-year-old male patient with tuberous xanthomas, xanthochromia striata palmaris, hypercholesterolemia, hypertriglyceridemia, chylomicronemia and a "broad-beta" band on agarose gel electrophoresis is the subject of this report. The classification of the metabolic disturbances as hyperlipoproteinemia, type III, with apo E-3 deficiency was derived from the results obtained by isoelectric focusing and density gradient ultracentrifugation. Since June 1983, the patient has been successfully treated with probucol (Lurselle) with no complementary diet. The serum cholesterol concentration was reduced by a maximum of 45%, together with clear regression of the xanthochromia striata palmaris and beginning xanthoma regression. The HDL cholesterol level did not climb again, and there were no side effects as a result of the probucol therapy.

Apolipoproteins E↗
PubMed1983

Induction of microsomal stearoyl-CoA desaturation by the administration of various peroxisome proliferators.

Male rats were fed a diet containing 0.5% p-chlorophenoxyisobutyric acid (clofibric acid), 1% acetylsalicylic acid, 2% di-(2-ethylhexyl)phthalate, 2% dibutylphthalate, 2% di-(2-ethylhexyl)adipate or 0.5% 4,4'-(isopropylidenedithio)bis(2,6-di-tert-butylphenol)) (probucol) for 7 days. Activity of microsomal stearoyl-CoA desaturation in rat liver was increased, ranging from 2.1 to 3.6 times, in association with an increase in the activity of peroxisomal beta-oxidation and catalase following the administration of clofibric acid, di-(2-ethylhexyl)phthalate, dibutylphthalate or di-(2-ethylhexyl)adipate. The increase in the activity of stearoyl-CoA desaturation by peroxisome proliferators appears to be due to an increase in activity only of the terminal desaturase, but not to changes in either NADH-cytochrome b5 reductase activity or cytochrome b5 content. Unlike peroxisome proliferators, probucol increased little the activity of either microsomal desaturation or peroxisomal beta-oxidation. The percentage of octadecenoic acid in total fatty acid of hepatic microsomes, homogenates and serum was increased markedly by the administration of peroxisome proliferators.

Adipates↗
PubMed1982

[Behavior of high-density lipoproteins in drug lipid-lowering treatment].

Changes in serum lipids, the individual lipoprotein fractions after ultracentrifugation and the apoproteins B, A1 and A2 were studied in 66 patients with primary hypercholesterolemia under treatment with different lipid-lowering agents. After 3 months with dietary treatment alone and a 4-week placebo period the patients were given bezafibrate (3 X 200 mg daily), colestipol (2 X 10 g per day) or probucol (2 X 500 mg daily) for 12 months, followed by another 4-week placebo period at the end of the study. Colestipol showed the best lipid-lowering effect (total and LDL cholesterol were decreased by 20% and 23% respectively) but satisfactory total and LDL cholesterol lowering results were also obtained with the other substances. However, the changes in HDL differed widely among the three substances: bezafibrate increased HDL cholesterol and the HDL apoproteins A1 and A2 significantly, colestipol did not alter these parameters, while probucol treatment was followed by a significant decrease in both HDL-cholesterol and the apoproteins A1 and A2.

Adult↗
PubMed1995

Effect of a lipid-lowering agent or a high-cholesterol diet on focal glomerulosclerosis in hyperlipidemic rats.

Hyperlipidemic rats given a diet supplemented with 1% probucol (4,4'-isopropylidenedithiobis [2,6-di-tert-butylphenol]) or 4% cholesterol with 1% cholic acid from 4 to 20 weeks of age were evaluated for the effect of a lipid-lowering agent or a high-cholesterol diet on focal glomerulosclerosis. Although mean cholesterol and phospholipid concentrations in hyperlipidemic rats given probucol were lower than those in control hyperlipidemic rats, there was no difference in urinary protein content or renal histologic findings when the two groups were compared. Mean cholesterol, phospholipid, urea nitrogen, and creatinine concentrations in hyperlipidemic rats given a high-cholesterol diet were greater than those in hyperlipidemic rats given a normal diet, and the glomerular sclerotic lesions became more severe.

Animals↗
PubMed1994

Tyrosyl radical generated by myeloperoxidase is a physiological catalyst for the initiation of lipid peroxidation in low density lipoprotein.

Myeloperoxidase, a heme protein secreted by activated phagocytes, is expressed in human atherosclerotic lesions. The enzyme uses H2O2 generated by the cells to oxidize L-tyrosine to tyrosyl radical, a catalyst for protein dityrosine synthesis. We have explored the possibility that tyrosyl radical initiates lipid peroxidation, which may be of pivotal importance in transforming low density lipoprotein (LDL) into atherogenic particles. Exposure of LDL to L-tyrosine and activated human neutrophils caused peroxidation of LDL lipids. LDL oxidation required L-tyrosine but was independent of free metal ions; catalase and heme poisons were inhibitory. Incubation of LDL with L-tyrosine, myeloperoxidase, and H2O2 likewise caused lipid peroxidation, and this reaction was inhibited by heme poisons and catalase. Replacement of L-tyrosine with O-methyltyrosine, which cannot form tyrosyl radical, inhibited LDL oxidation by both activated neutrophils and myeloperoxidase. The antioxidants ascorbate and probucol, but not vitamin E, inhibited LDL oxidation by myeloperoxidase, H2O2, and L-tyrosine. Ascorbate blocked dityrosine synthesis, while probucol scavenged chain-propagating peroxyl radicals in the lipid phase of LDL. These results indicate that tyrosyl radical stimulates LDL lipid peroxidation. In striking contrast to other cell-mediated mechanisms for LDL oxidation, the myeloperoxidase-catalyzed reaction is independent of free metal ions. This raises the possibility that tyrosyl radical generated by myeloperoxidase is of physiological importance in making LDL atherogenic.

Ascorbic Acid↗
PubMed1994

Lipoprotein fractionation in deuterium oxide gradients: a procedure for evaluation of antioxidant binding and susceptibility to oxidation.

Oxidative modifications of lipoproteins appear to contribute to their atherogenicity. Very low and low density lipoproteins (VLDL and LDL) are protected against these modifications by antioxidants that can be incorporated in vivo or in vitro into the particles. We describe here ultracentrifugal procedures for isolation of VLDL and LDL that do not require subsequent dialysis or buffer equilibration. Lipoproteins were isolated in buffers with physiological ionic composition prepared in D2O (deuterium oxide). This allowed measurements of the content of antioxidants and of the susceptibility to oxidation of the isolated LDL without further manipulations. Conventional ultracentrifugal methods use high salt concentrations and require additional steps to eliminate them. This introduces uncertainties in the evaluation of antioxidant binding and on measurements of their effect on VLDL and LDL oxidation. With the method described, the composition of the isolated VLDL and LDL was indistinguishable from that of fractions isolated with KBr gradients. Also, the content of alpha-tocopherol was similar. LDL isolated with KBr solutions appeared to bind 20-45% more of the probucol present in serum than LDL isolated in isotonic solutions prepared with D2O. This was the case with probucol incorporated into plasma or serum in vivo or in vitro. Five out of seven LDL isolated with the D2O procedure from different human sera appeared more resistant to Cu(2+)-catalyzed oxidation than those obtained with KBr gradients from the same serum. In addition to the gradient procedure, we also describe a preparative version of the method that can be used with multiple samples.

Animals↗
PubMed1993

[Ticlopidine may prevent subtotal or total occlusion of dilated lesions after percutaneous coronary angioplasty].

The efficacy of ticlopidine and probucol plus oryzanol for reducing restenosis after dilation was examined in 151 patients with 229 stenotic lesions treated by coronary angioplasty after complete resolution of associated acute myocardial infarction, unstable angina, and variant angina. The stenotic lesions were 90% or less in diameter and less than 10 mm in length, and residual stenosis was 40% or less after treatment. Patients were randomly assigned to receive no medication, ticlopidine (200 mg daily) and/or probucol (1,000 mg daily) plus oryzanol (300 mg daily). One hundred forty-six patients with 220 dilated lesions were examined angiographically to evaluate restenosis. The medications achieved no clear reduction in restenosis, but subtotal or total reocclusion occurred in 6 of 102 patients not receiving ticlopidine, and in none of 118 patients receiving ticlopidine (p < 0.008). Ticlopidine may prevent subtotal or total reocclusion in dilated lesions.

Angioplasty, Balloon, Coronary↗
PubMed1996

Effects of hypolipidemic drugs on the expression of genes involved in high density lipoprotein metabolism in the rat.

Since plasma high density lipoprotein (HDL) concentrations are inversely related to the development of atherosclerosis, induction of HDL after pharmacological treatment is considered of benefit. To study whether currently used hypolipidemic drugs affect HDL metabolism by modulating the expression of genes involved in HDL metabolism, liver and intestinal apolipoprotein (apo) AI, apo-AII and apo-AIV gene expression was evaluated in rats treated with different classes of hypolipidemic drugs, and correlated to the changes in plasma lipid and apolipoprotein concentrations. In rats, the most pronounced hypolipidemic effects were observed after treatment with the fibrates clofibrate and fenofibrate, which lowered plasma lipid, apo-AI and apo-AIV concentrations. This decrease was accompanied by lowered liver apo-AI, apo-AII and apo-AIV mRNA levels. None of the other compounds tested affected plasma cholesterol, whereas probucol and simvastatin decreased plasma triglyceride concentrations. Apo-AI and apo-AII mRNA remained constant after nicotinic acid and probucol, whereas liver apo-AIV mRNA levels decreased. Cholestyramine increased hepatic apo-AI and apo-AII, but not apo-AIV mRNA levels. Simvastatin treatment increased apo-AI mRNA nearly threefold, whereas apo-AII and apo-AIV decreased by more than 50%. Similarly as after cholestyramine, the alteration in hepatic apo-AI mRNA levels did not result in changed plasma apo-AI concentrations. Remarkably, none of the drugs tested significantly affected intestinal apolipoprotein mRNA levels. These results indicate that hypolipidemic drugs may act on plasma lipoprotein metabolism by regulating apolipoprotein gene expression. Further studies in humans and primates are therefore warranted.

Actins↗