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PubMed2003

Probucol in the treatment of non-alcoholic steatohepatitis: a double-blind randomized controlled study.

BACKGROUND/AIMS: A final step in the pathology of non-alcoholic steatohepatitis (NASH) is oxidative damage to hepatocytes. Probucol is a lipid-lowering agent with strong antioxidant properties. We designed a double-blind randomized controlled study to evaluate the effects of probucol in NASH. METHODS: Thirty cases of biopsy-proven NASH were included. Subjects were randomly allocated to either the treatment group or to the control group by a 2:1 ratio. The treatment group was given 500 mg of probucol daily for 6 months, and the control group, an identically appearing placebo. RESULTS: Twenty-seven cases completed the study. The mean aspartate transaminase (AST) and alanine transaminase (ALT) levels changed from 81.9 to 36.2 and 102.2 to 44.7 in the treatment group and from 57.6 to 49.6 and 96.8 to 96.2 in the control group, respectively. The decrease in ALT level in the treatment group as compared to the control group was significant at the P<0.005 level (95% confidence interval: 20.2-93.7 IU). Both AST and ALT levels dropped to normal in nine cases of the treatment group (50%) but none of the control group (P=0.01). CONCLUSIONS: Probucol appears to be significantly effective in decreasing the ALT levels in patients with NASH.

Adult↗
PubMedDate not supplied

Formation of malonaldehyde in the presence of probucol, an anti-atherosclerosis drug.

Formation and inhibition of malonaldehyde (MA) from blood plasma lipids oxidized by Fenton's reagent in the absence or presence of probucol [4,4'-(isopropylidenedithio)bis(2,6-di-tert-butylphenol)] and L-ascorbic acid were investigated. The amount of MA formed was quantitatively analysed by gas chromatography. L-Ascorbic acid inhibited MA formation by about 30% at the level of 4.0/micromol, but the amount of MA formed was increased by the presence of probucol. When 3.0 micromol oxidized probucol was hydrolysed at pH 1. 3 and 5, 2616.5 nmol, 287.5 nmol and 103.9 nmol MA were recovered, respectively. This is the first report of quantitative analysis of MA formed from probucol on oxidation.

Animals↗
PubMed1999

Probucol suppresses ICAM-1 expression in rat mesangial cells: possible role of IL-1.

Interleukin-1 (IL-1) participates in the progression of glomerulonephritis by up-regulating intercellular adhesion molecule-1 (ICAM-1) expression in experimental glomerulonephritis. Probucol, an anti-hyperlipidemic agent, ameliorates some types of glomerulonephritis regardless of serum cholesterol levels, and is also reported to inhibit IL-1 release from macrophages in atherosclerotic lesions. However, little is known about the mechanism of this favorable action on glomerular injury. We examined whether or not probucol inhibits ICAM-1 expression by suppression of IL-1 action in cultured rat mesangial cells. In this brief report, we review the actions of probucol on IL-1 secretion and discuss the possible mechanism by which probucol may suppress the glomerular injury.

Animals↗
PubMed1999

Effect of probucol on hypercholesterolemia in renal transplant patients.

BACKGROUND: Hypercholesterolemia is a well-known complication in kidney transplant recipients, although its pathogenesis may be multifactorial. The therapeutic effect of probucol on post-transplant hypercholesterolemia was prospectively evaluated. METHODS: Twelve hypercholesterolemic kidney transplant patients with serum total cholesterol > or = 250 mg/dl without diabetes mellitus or hypoproteinemia were prospectively treated with probucol (250 mg, bid, for three months). Before initiating and at the end of treatment, blood was drawn after at least a 12-hour fast to measure lipids in serum and lipoprotein fractions, apoproteins (apo), lipoprotein fractions, lethicin cholesterol acyl transferase (LCAT), free fatty acids (FFAs), and cholesterol ester. The lipid profiles of 17 healthy subjects were also examined. RESULTS: After treatment with probucol, serum total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and apo AI were significantly decreased, whereas cholesterol ester increased significantly. CONCLUSIONS: Post-transplant hypercholesterolemia is featured with abnormalities in very low-density lipoprotein (VLDL) metabolism. Although HDL cholesterol decreased, probucol might have acted as an antiatherogenic by modulating HDL metabolism and stimulating reverse transfer of cholesterol from peripheral tissue.

Adult↗
PubMed1998

Effect of probucol on serum lipoprotein and apoprotein profiles in renal transplant patients.

The therapeutic effect of probucol on hypercholesterolemia in cyclosporine A (CyA)-treated renal transplant patients was prospectively studied. Twelve posttransplantation patients aged 34.2+/-2.5 years with serum total cholesterol (t-CHL) of 250 mg/dL or greater, whose serum creatinine was 2.9 mg/dL or less, and who had no diabetes mellitus or hypoproteinemia, were treated with probucol, 250 mg twice daily for 3 months. Seventeen age-matched (36.8+/-1.6 years) normal volunteers served as control. Blood was drawn after at least a 12-hour fast to measure lipids in serum and lipoprotein fractions, apoproteins (apo), lipoprotein fractions, lethicin cholesterol acyl transferase (LCAT), free fatty acids (FFA), and CHL-ester. Serum t-CHL, triglycerides (TG), and phospholipids (PL) in posttransplantation patients before treatment were significantly higher compared with normal control subjects. Very-low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) fractions in these patients were significantly expanded. The pretreatment levels of serum apo AII, B, CII, and CIII were significantly increased compared with those of normal controls. After treatment with probucol, serum t-CHL, LDL-CHL, high-density lipoprotein (HDL)-CHL, PL, LDL-PL, and apo AI were significantly decreased, and CHL-ester significantly increased compared with the pretreatment levels. These data suggest that although probucol causes a decrease in HDL-CHL, it may act anti-atherogenically by modulating HDL metabolism and stimulating reverse transfer of CHL from peripheral tissue.

Adult↗
PubMed1995

Probucol prevents the progression of fatty liver in MSG obese mice.

We investigated the effect of Probucol in preventing fatty liver in monosodium-L-glutamate (MSG) treated obese mice and control mice fed a high fat diet. MSG mice became significantly obese 9 weeks after birth with higher levels of serum blood glucose, total cholesterol, HDL-cholesterol, GPT, and cholinesterase, and had greater triglyceride contents in their livers relative to control mice. Morphologically, MSG obese mice also had a marked fatty liver. Administration of Probucol mixed with the high fat diet for 2 weeks significantly decreased the serum levels of total cholesterol and HDL-cholesterol, and liver triglyceride contents in both MSG and control mice. Morphologically, the livers were less fatty after Probucol treatment. These results suggest that Probucol prevents the development of fatty liver, and in addition reduces hypercholesterolemia.

Animals↗
PubMed2003

Probucol prevents early coronary heart disease and death in the high-density lipoprotein receptor SR-BI/apolipoprotein E double knockout mouse.

Mice with homozygous null mutations in the high-density lipoprotein receptor SR-BI (scavenger receptor class B, type I) and apolipoprotein E genes fed a low-fat diet exhibit a constellation of pathologies shared with human atherosclerotic coronary heart disease (CHD): hypercholesterolemia, occlusive coronary atherosclerosis, myocardial infarctions, cardiac dysfunction (heart enlargement, reduced systolic function and ejection fraction, and ECG abnormalities), and premature death (mean age 6 weeks). They also exhibit a block in RBC maturation and abnormally high plasma unesterified-to-total cholesterol ratio (0.8) with associated abnormal lipoprotein morphology (lamellar/vesicular and stacked discoidal particles reminiscent of those in lecithin/cholesterol acyltransferase deficiency and cholestasis). Treatment with the lipid-lowering, antiatherosclerosis, and antioxidation drug probucol extended life to as long as 60 weeks (mean 36 weeks), and at 5-6 weeks of age, virtually completely reversed the cardiac and most RBC pathologies and corrected the unesterified to total cholesterol ratio (0.3) and associated distinctive abnormal lipoprotein morphologies. Manipulation of the timing of administration and withdrawal of probucol could control the onset of death and suggested that critical pathological changes usually occurred in untreated double knockout mice between approximately 3 (weaning) and 5 weeks of age and that probucol delayed heart failure even after development of substantial CHD. The ability of probucol treatment to modulate pathophysiology in the double knockout mice enhances the potential of this murine system for analysis of the pathophysiology of CHD and preclinical testing of new approaches for the prevention and treatment of cardiovascular disease.

Age Factors↗
PubMed1987

Probucol prevents the progression of atherosclerosis in Watanabe heritable hyperlipidemic rabbit, an animal model for familial hypercholesterolemia.

In this study, we questioned whether in vivo probucol could prevent the progression of atherosclerosis in homozygous Watanabe heritable hyperlipidemic (WHHL) rabbits, an animal model for familial hypercholesterolemia. At 2 months of age, eight WHHL rabbits were divided into two groups. Group A (n = 4) was fed standard rabbit chow for 6 months. Group B (n = 4) was fed standard rabbit chow containing 1% probucol for 6 months. At the end of the experiments, average plasma concentrations of cholesterol were 704 +/- 121 mg/dl in group A and 584 +/- 61 mg/dl in group B, respectively. The percentage of surface area of total thoracic aorta with visible plaques in group A versus group B was 54.2% +/- 18.8% versus 7.0% +/- 6.3%, respectively. What was noteworthy was that the percentage of plaque in the descending thoracic aorta was almost negligible (0.2% +/- 0.2%) in group B rabbits compared to that in group A rabbits (41.1% +/- 20.2%). Low density lipoproteins (LDL) isolated from WHHL rabbits under treatment with probucol (group B) were shown to be highly resistant to oxidative modification by cupric ion and to be minimally recognized by macrophages. On the contrary, LDL from group A rabbits incubated with cupric ion showed a 7.4-fold increase in peroxides (thiobarbituric acid-reactive substances) and a 4.3-fold increase in the synthesis of cholesteryl ester in macrophages compared to those of LDL from group B rabbits. Thus, probucol could definitely prevent the progression of atherosclerosis in homozygous WHHL rabbits in vivo by limiting oxidative LDL modification and foam cell transformation of macrophages.

Animals↗
PubMed1997

Clinical evaluation of probucol in hypercholesteremia: individual lipoprotein responses and inhibitory effect on carotid atherosclerosis progression.

Probucol treatment has been evaluated in 140 patients with hypercholesterolemia attending a single Lipid Clinic, in an attempt to identify the relations between lipid/lipoprotein responses and patient characteristics. Probucol was administered as a single drug at the standard dose (0.5 g tablets b.i.d.) for at least 6 months. One-hundred (71%) patients displayed a reduction of low-density lipoprotein cholesterol (LDL-C), which was significantly correlated with the baseline LDL-C level (r = 0.64; p < 0.0001). Most of the patients (90%) also responded with a reduction of high-density lipoprotein cholesterol (HDL-C); the HDL-C reduction was also directly related to baseline HDL cholesterolemia (r = 0.67, p < 0.0001). A highly significant correlation was found between the individual LDL-C and HDL-C responses. Eleven patients who continued with probucol treatment had a B-mode ultrasonographic investigation performed at baseline and after 24 months. No changes in carotid mean and maximal intimal-medial thickness were recorded, in contrast to an increase (i.e., indicative of atherosclerosis progression) in matched patients with hypercholesterolemia receiving other lipid-lowering regimens. Our report underlines that probucol can still provide a valuable option for the treatment for hypercholesterolemia, being particularly effective in patients with a combined increase of LDL-C and HDL-C levels.

Adult↗
PubMed2003

Pharmacologic prevention of both restenosis and atherosclerosis progression: AGI-1067, probucol, statins, folic acid and other therapies.

PURPOSE OF REVIEW: In this article, the authors intend to provide an update on clinical trials of pharmacologic prevention of restenosis after percutaneous coronary interventions, placed in the perspective of the use of orally administered therapy for the prevention of atherosclerosis progression and clinical events. RECENT FINDINGS: AGI-1067, the mono-succinic acid ester of probucol, is a phenolic antioxidant member of a novel class of agents termed v-protectants. It has strong antioxidant properties equipotent to those of probucol and antiinflammatory properties. It inhibits gene expression of VCAM-1 and MCP-1 and has been effective at preventing atherosclerosis in all tested animal models including the non-human primate. In the Canadian Antioxidant Restenosis Trial (CART) 1, AGI-1067 and probucol improved lumen dimensions at the site of percutaneous coronary intervention. AGI-1067 also improved luminal dimensions of non-intervened coronary reference segments in the Canadian Antioxidant Restenosis Trial, which suggests a direct antiatherosclerosis effect. Probucol reduced post-percutaneous coronary intervention restenosis and progression of carotid atherosclerosis in other clinical trials. Although statins reduce atherosclerotic events, they do not appear to have a significant effect on restenosis. The failure of folate therapy to protect against restenosis in the Folate After Coronary Intervention Trial (FACIT) occurred despite significant reductions in homocysteine levels. SUMMARY: Prevention of both post-percutaneous coronary intervention restenosis and atherosclerosis progression with a pharmacologic agent such as AGI-1067 may be an attractive treatment paradigm. Two important trials that test the antioxidant/antiinflammatory hypothesis are ongoing with AGI-1067: the Canadian Atherosclerosis and Restenosis Trial 2, which assesses its value for the reduction of both atherosclerosis progression and post-percutaneous coronary interventions restenosis, and the Aggressive Reduction of Inflammation Stops Events (ARISE) trial which is evaluating its effects on cardiovascular events.

Anti-Inflammatory Agents↗
PubMed1996

A comparative study of the therapeutic effect of probucol and pravastatin on xanthelasma.

We examined and compared the effects of probucol and pravastatin on the regression of xanthelasma. Thirty-six cases treated by probucol and 18 cases by pravastatin were evaluated for 12 months. Thirteen of the 36 cases treated with probucol showed regression of xanthelasma. However, one of the 18 cases treated with pravastatin showed regression. These data were statistically significantly. The average total cholesterol value in both groups decreased during drug therapy. However, the average of HDL-cholesterol values in the probucol treatment group showed significant decreases, but those in the pravastatin treatment group did not. We discussed the mechanisms of the two drugs on the regression of xanthelasma and the mechanisms of development of xanthelasma.

Adult↗
PubMed1991

Probucol increases cholesteryl ester transfer protein activity in hypercholesterolaemic patients.

Probucol, a widely used lipid lowering drug, reduces both low- and high-density (LDL and HDL) lipoprotein levels and can induce a regression of tissue lipid deposits in both animals and man. The suggested mechanism(s) involve the prevention of LDL oxidative modifications and, possibly, an improvement in the reverse cholesteryl ester transport system. Probucol administration to 10 hypercholesterolaemic patients increased the activity of the cholesteryl ester transfer protein (CETP) by 50%. The rise of CETP activity was significantly related with the plasma steady-state drug levels (r = 0.51, P less than 0.005), thus suggesting that probucol may directly stimulate CEPT synthesis and/or release. Furthermore, CETP activity was inversely related with HDL-cholesterol levels, both in the whole series of 10 patients (r = -0.56, P less than 0.001) and, more so, in the single individuals (r between -0.77 and -0.97), thus suggesting that the reduction of plasma HDL-cholesterol levels is a direct consequence of CETP stimulation. These findings support the hypothesis that an improvement in the reverse cholesteryl ester transport is a major mechanism of probucol and that this may explain the drug induced plasma lipoprotein changes.

Arteriosclerosis↗
PubMed1994

The effect of probucol and vitamin E treatment on the oxidation of low-density lipoprotein and forearm vascular responses in humans.

This study investigates the hypothesis that lipid soluble antioxidants may increase the resistance of low-density lipoprotein (LDL) to oxidation and also enhance vascular endothelial responses in humans. In a double-blind parallel group study, 24 hypercholesterolaemic patients already on treatment with simvastatin (20 mg day-1), were randomized to supplementary treatment with probucol (500 mg bd), vitamin E (400 IU daily) or placebo for 8 weeks. Mean serum cholesterol before antioxidant treatment was 7.00 mmol l-1. Resistance of LDL to oxidation by copper was increased by 830% in the probucol group and by 30% in the vitamin E group. However, thiobarbituric acid reacting substances in whole serum were not altered by either antioxidant. Probucol lowered HDL- and LDL-cholesterol levels and increased the QT interval. Forearm vascular responses, as measured by venous occlusion plethysmography, to acetylcholine, glyceryl trinitrate and NG-monomethyl-L-arginine, were not significantly changed by antioxidant treatment. Probucol has a major, and vitamin E a minor, effect on LDL resistance to oxidation but neither compound appears to alter forearm vascular responses in vivo.

Adult↗
PubMed2004

Protection of chylomicron remnants from oxidation by incorporation of probucol into the particles enhances their uptake by human macrophages and increases lipid accumulation in the cells.

The effects of protection of chylomicron remnants from oxidation on their uptake and induction of lipid accumulation in macrophages were investigated using chylomicron remnant-like particles (CRLPs) containing the lipophilic antioxidant drug, probucol, and macrophages derived from the human monocyte cell line, THP-1. The total lipid content of THP-1 macrophages was markedly higher (x2.2) after 48 h of incubation of THP-1 macrophages with CRLPs containing probucol (pCRLPs) when compared to CRLPs without probucol, and this was because of increases in triacylglycerol (x2.3) and cholesterol (x1.8) levels, while cholesteryl ester concentrations were not significantly changed. Determination of the uptake of CRLPs and pCRLPs by the cells using particles labelled with the fluorescent probe 1,1'-dioctadecyl-3,3,3'3'-tetramethylindo-carbocyanine perchlorate showed that pCRLPs are taken up at a faster rate than CRLPs. The synthesis of triacylglycerol, as measured by the incorporation of [(3)H]oleate and [(3)H]glycerol, was also increased in macrophages incubated with pCRLPs as compared to CRLPs without probucol, but phospholipid and cholesteryl ester formation from [(3)H]oleate was unaffected. In addition, no differences between the effects of CRLPs and pCRLPs on the expression of mRNA for a range of genes believed to be involved in lipoprotein uptake, intracellular lipid metabolism and the efflux of cholesterol from macrophages was detected. These results suggest that antioxidants carried in chylomicron remnants enhance lipid accumulation in macrophages by increasing the rate of uptake of the particles and raising the intracellular synthesis of triacylglycerol, but not cholesteryl ester, and that these effects are brought about by changes at the post-transcriptional level. Antioxidants carried in chylomicron remnants therefore may promote the development of atherosclerosis, and this is likely to be particularly important in conditions where clearance of remnants from the circulation is delayed.

Animals↗
PubMed2004

Effects of probucol on renal function and urinary protein excretion in spontaneously hypercholesterolemic rats fed a normal or high cholesterol diet.

BACKGROUND/AIM: Spontaneously hypercholesterolemic (SHC) rats develop hypercholesterolemia and focal glomerular sclerosis, and have been thought to be a model of lipid-induced glomerular injury. However, recent studies suggest that the hypercholesterolemia might be due to secondary mechanisms by massive proteinuria. The purpose of the present study was to determine in SHC rats the effects of a high cholesterol diet on serum lipid profiles and renal function/histology, and to examine whether or not the model of lipid-induced renal injury could be developed in a short period of the time. The effects of probucol were also studied. METHODS: SHC rats were fed a high cholesterol diet for 6 weeks (H) or with probucol (HP), while control SHC rats were fed normal rat chow (N) or with probucol (P). Lipid profile and renal function/histology were examined. RESULTS: H and HP showed increased levels of urinary protein excretion and serum creatinine, as well as extremely high serum cholesterol levels, compared with N and P. HP tended to show reduced urinary protein excretion compared with H, but the difference was not statistically significant. H and HP presented histologically characteristic changes with numerous foam cells accumulated in the glomerular mesangial area, and showed glomerular sclerosis. CONCLUSION: The data demonstrate that SHC rats have an intrinsically abnormal lipid metabolism, and that probucol does not exert obviously beneficial effects on renal function or lipid-lowering action. A lipid-induced renal injury model of rats was produced in 6 weeks.

Animals↗
PubMed1992

Probucol attenuates a reduction in serum immunoreactive insulin levels by interleukin in adrenalectomized rats.

We determined a protective action of probucol (4,4'-[isopropylidenedithio]bis[2,6-di-tert-butylphenol]) on the reduction of serum immunoreactive insulin (IRI) levels by recombinant human interleukin-1 beta (IL-1) in adrenalectomized rats. IL-1 reduced the serum IRI levels 4 h after injection in rats fed a standard diet. However, IL-1 failed to inhibit serum IRI levels in rats fed a diet containing 1% probucol. In contrast, IL-1 decreased plasma glucose levels in both groups. Although IL-1 reduced plasma prostaglandin (PG) E2 levels in standard diet-fed rats, IL-1 did not affect plasma PGE2 levels in the animals fed the probucol-containing diet. The present study suggested that the free radical scavenger action of probucol can block the IL-1 effect on serum IRI levels.

Administration, Oral↗
PubMed1993

Influence of probucol on enhanced LDL oxidation after fish oil treatment of hypertriglyceridemic patients.

The susceptibility of low-density lipoprotein (LDL) to oxidation was studied in hypertriglyceridemic men (5 with type III and 5 with type IV) at baseline on a low-saturated-fat, low-cholesterol diet, after 6 weeks of dietary supplementation with fish oil (Promega, 12 g/d), and after 6 weeks of fish oil combined with probucol (500 mg BID). The relative content of n-3 polyunsaturated fatty acids in plasma and LDL was increased during the two treatment periods, and a low alpha-tocopherol to n-3 polyunsaturated fatty acids ratio was observed. Plasma thiobarbituric acid-reactive substances (TBARS) levels were unchanged after 6 weeks of fish oil, but the ratio of lipid peroxides to the reduced triglyceride (TG) levels (MDA:TG) was significantly higher (P < .01). Addition of probucol lowered both absolute levels of TBARS (P < .01) and the MDA to TG ratio (P < .001). The susceptibility of LDL to Cu(2+)-catalyzed oxidation was evaluated over a 5-hour time course by determining TBARS formation, free amino group levels, and changes in LDL electrophoretic mobility. TBARS levels that were higher in native LDL (1.019 < d < 1.050 g/mL) after 6 weeks of fish oil than at baseline (P < .01) were reduced 52.3 +/- 11.3% by the addition of probucol (P < .001). With fish oil alone, TBARS production after exposure of LDL to Cu2+ for 5 hours was increased 17.0 +/- 5.8% compared with corresponding baseline values (P < .001), whereas a 64.1 +/- 14.3% reduction from the previous period was observed with fish oil + probucol (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Probucol reduces the cellularity of aortic intimal thickening at anastomotic regions adjacent to prosthetic grafts in cholesterol-fed rabbits.

Intimal hyperplasia is a persistent problem after implantation of prosthetic grafts. Although the mechanisms underlying this hyperplastic response are unknown, it has been proposed that such responses may be due to chronic vascular injury similar to that of atherogenesis. Thus, the role of oxidation was explored using the potent antioxidant drug probucol. Adult New Zealand White rabbits fed a modestly (0.25%) cholesterol-enriched diet had a polytetrafluoroethylene prosthetic graft placed into the lower aorta. After the grafting procedure, a group of 11 rabbits was placed on the cholesterol-enriched diet supplemented with 1% wt/wt probucol while a control group of 10 rabbits was placed on the cholesterol-enriched diet alone. The rabbits were maintained for a further 10 weeks before histological examination of the area surrounding the graft. Although administration of probucol did not significantly alter the dimensions of lesions at the anastomotic sites, the drug promoted striking histological changes in the surrounding tissue. Both groups of rabbits had a similar intimal hyperplastic response of the aortic tissue surrounding the graft. The vascular lesions present in the perigraft region of the control group consisted of a normal-appearing media but a thickened intima. The thickened intima contained numerous smooth muscle cells in a network of extracellular matrix. Regions in the neointima that were rich in smooth muscle cells exhibited modest staining for proliferating cell nuclear antigen. A few macrophages were present in the control group as determined by immunostaining with the monoclonal antibody RAM-11. In contrast, administration of probucol led to a marked reduction in the presence of RAM-11-staining macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗