Atherosclerotic lesion development in hypercholesterolemic Japanese quail following probucol treatment: a biochemical and morphologic evaluation

Effects of probucol in hyperlipidemic rabbit liver: a preliminary ultrastructural study

Probucol is a lipid-lowering agent with an antioxidant effect; however, its influence on the liver remains unclear. The effects of probucol on hyperlipidemic rabbit liver are investigated to add a structural data on its therapeutical profile. Local albino rabbits were divided into three groups. 1) Hyperlipidemic group: fed with 1% cholesterol (150 g/kg/day) enriched chow for 2 months. 2) Probucol treated group: group 1 + intraperitoneal probucol (10 mg/kg/day) administration for 15 days. 3) Control group fed with normal chow. The blood lipid profile was investigated biochemically. Liver samples were examined electronmicroscopically. Within the parenchymal cells of group 1, the amount of rough surfaced endoplasmic reticulum was increased, its cisterna was dilated displaying a moderately electron dense substance in it and showed close apposition with the condensed mitochondria. In group 2, smooth surfaced endoplasmic reticulum was in extensive amounts filling almost all of the cytoplasm, displayed a reticular, degenerated appearance and was in close relation with the condensed, degenerated mitochondria. Probucol may cause degenerative changes on the liver parenchyme at the subcellular level. It alters the structure of these cells mainly acting on the smooth surfaced endoplasmic reticulum and the mitochondria that are known to be involved in cellular detoxification.

Selective neointimal gene transfer in an avian model of vascular injury

Avian models of atherosclerosis helped pioneer the study of vascular biology, and offer economic and technical advantages over mammalian models. As an initial step towards investigating important molecular pathways involved in avian atherogenesis and restenosis, we developed a recombinant adenovirus (Ad) which expresses the reporter gene beta-galactosidase (beta-gal), and applied it to cultured chicken vascular smooth muscle cells (SMCs) and a rooster model of acute vascular injury. In cultured chicken SMCs, recombinant gene expression increased as a function of multiplicity of infection (MOI) and incubation time. Maximal expression occurred at an MOI of 10(4) plaque-forming units (pfu)/cell with approximately 50% of quiescent and non-quiescent chicken SMCs expressing beta-gal. Human aorta SMCs had two- to four-fold increased beta-gal expression compared with chicken SMCs at all MOI and incubation times. In vivo instillation of recombinant Ad into uninjured rooster femoral artery segments revealed low efficiency endothelial cell expression of the reporter gene. In contrast, recombinant Ad infection of rooster femoral artery segments 3-21 days after balloon injury revealed up to 60% of luminal surface beta-gal expression, confined predominantly to the neointimal layer. Peak reporter gene expression efficiencies occurred in arterial segments infected 3 days after balloon injury. Uninfected and control Ad infected arteries had no detectable beta-gal expression. Rooster neointimal cells targeted by the recombinant Ad were identified as alpha-smooth muscle actin containing cells by immunohistochemistry. We conclude that Ad-mediated gene transfer is efficient and selective for the neointima in the rooster acute vascular injury model, and offers the potential to efficiently introduce exogenous genes that may impact on the injury response. This model of acute vascular injury may also be manipulated into more established avian models of atherosclerosis, permitting the investigation of acute injury progression to chronic injury.

Oxidants and antioxidants in the pathogenesis of atherosclerosis: implications for the oxidized low density lipoprotein hypothesis

The oxidation hypothesis proposes that low density lipoprotein must be oxidatively modified to trigger the pathological events of atherosclerosis. In this article, we evaluate recent studies addressing the pathways that promote low density lipoprotein oxidation in vivo and the impact of antioxidants on atherogenesis in animals, paying particular attention to the clinical implications of these studies for the oxidation hypothesis.

Antioxidant effects of tocotrienols in patients with hyperlipidemia and carotid stenosis

Antioxidants may have a role in the prevention of atherosclerosis. In the present trial, we investigated the antioxidant properties of Palm Vitee, a gamma-tocotrienol-, and alpha-tocopherol enriched fraction of palm oil, in patients with carotid atherosclerosis. Serum lipids, fatty acid peroxides, platelet aggregation and carotid artery stenosis were measured over an 18-month period in fifty patients with cerebrovascular disease. Change in stenosis was measured with duplex ultrasonography. Ultrasound scans were done at six months, twelve months, and yearly thereafter. Bilateral duplex ultrasonography revealed apparent carotid atherosclerotic regression in seven and progression in two of the 25 tocotrienol patients, while none of the control group exhibited regression and ten of 25 showed progression (P < 0.002). Serum thiobarbituric acid reactive substances, an ex vivo indicator of maximal platelet peroxidation, decreased in the treatment group from 1.08 +/- 0.70 to 0.80 +/- 0.55 microM/L (P < 0.05) after 12 mon, and in the placebo group, they increased nonsignificantly from 0.99 +/- 0.80 to 1.26 +/- 0.54 microM/L. Both tocotrienol and placebo groups displayed significantly attenuated collagen-induced platelet aggregation responses (P < 0.05) as compared with entry values. Serum total cholesterol, low density lipoprotein cholesterol, and triglyceride values remained unchanged in both groups, as did the plasma high density lipoprotein cholesterol values. These findings suggest that antioxidants, such as tocotrienols, may influence the course of carotid atherosclerosis.