Aortas Of Cholesterol-fed Rabbits Research Articles

ANTI-ATHEROSCLEROTIC ACTIVITY OF ELAEOCARPUS GANITRUS ROXB. IN CHOLESTEROL-FED RABBITS

Objectives: Atherosclerosis was experimentally induced in New Zealand white male rabbits by cholesterol feeding for 120 days for investigating effects of 70% ethanolic Elaeocarpus ganitrus seed extract (EEGS) against atherosclerosis.Methods: Anti-atherosclerotic activity of E. ganitrus extract was evaluated at a dose level of 250 and 500 mg/kg of body weight (p.o). On 121st day, the animals were sacrificed to collect the aorta for determining tissue lipid profile, antioxidant parameters, and histopathological changes. One-way ANOVA followed by Tukey’s multiple comparison test was used for the statistical analysis.Results: Aorta of cholesterol-fed rabbits for 120 days showed marked elevation in total cholesterol, triglycerides, and phospholipids. EEGS extract treatment significantly (p≤0.01, ≤0.001) corrected disturbed lipid profile in cholesterol-fed rabbits in a dose-dependent manner during the 60 days of the treatment period. A significant reduction in lipid peroxidation and a considerable raise in glutathione, catalase, and superoxide dismutase levels (p≤0.01, ≤0.001) were accompanied by post-treatment with EEGS extract to cholesterol-fed rabbits. The histopathological modifications such as accumulation of foam cells, atheromatous plaque formation, and lumen size reduction supported the successful induction of atherosclerosis in rabbits. The treated rabbits showed significant protective effect by lowering the deposition of cholesterol and increasing the lumen size compared to cholesterol-fed group.Conclusions: Phytoconstituents such as alkaloids, tannins, flavonoids, steroids, triterpenoids, and carbohydrates in the ethanolic extract may be attributed to effective anti-atherosclerotic and antioxidant activity of plant extract. Our study exhibited that EEGS extract could be a potent herbal therapeutic agent for the treatment of atherosclerosis and hypercholesterolemia-related diseases.

Modelling atherosclerosis by proteomics: Molecular changes in the ascending aortas of cholesterol-fed rabbits.

The cholesterol-fed rabbit is commonly used as a model to study the vascular effects of hypercholesterolemia and resulting atherosclerotic lesions. Here we undertook a proteomic case-control investigation of ascending aortas from male New Zealand White rabbits after 10 weeks on a high-cholesterol (2% w/w) diet (HCD, n = 5) or control diet (n = 5), in order to determine the changes in response to the HCD. Histology confirmed intimal thickening in the HCD group consistent with atherosclerosis, and LC-MS/MS analysis of individually-obtained ascending aortic extracts labelled with isobaric (iTRAQ) tags enabled the identification and quantitation of 453 unique proteins above the 1% false discovery rate threshold. Of 67 proteins showing significant differences in relative abundance (p < 0.05), 62 were elevated and five decreased in ascending aortas from HCD-fed rabbits compared to controls. Six proteins were selected for validation using Multiple Reaction Monitoring, which confirmed the iTRAQ results. Many of the observed protein changes are consistent with known molecular perturbations in the ascending aorta that occur in response to hypercholesterolemia, e.g. elevation of tissue levels of apolipoproteins, extracellular matrix adhesion proteins, glycolytic enzymes, heat shock proteins and proteins involved in immune defense. We also made a number of novel observations, including a 15-fold elevation of glycoprotein (trans-membrane) nmb-like (Gpnmb) in response to HCD. Gpnmb has previously been linked to angiogenesis but not to atherosclerosis. This and additional novel observations merit further investigation as these perturbations may play important and as yet undiscovered roles in the pathogenesis of atherosclerosis in rabbits as well as humans.

Contrast Ultrasound Imaging Does Not Affect Heat Shock Protein 70 Expression in Cholesterol-Fed Rabbit Aorta.

Diagnostic ultrasound imaging is enhanced by the use of circulating microbubble contrast agents (UCAs), but the interactions between ultrasound, UCAs, and vascular tissue are not fully understood. We hypothesized that ultrasound with a UCA would stress the vascular tissue and increase levels of heat shock protein 70 (Hsp70), a cellular stress protein. Male New Zealand White rabbits (n = 32) were fed a standard chow diet (n = 4) or a 1% cholesterol, 10% fat, and 0.11% magnesium diet (n = 28). At 21 days, 24 rabbits on the cholesterol diet were either exposed to ultrasound (3.2-MHz f/3 transducer; 2.1 MPa; mechanical index, 1.17; 10 Hz pulse repetition frequency; 1.6 microseconds pulse duration; 2 minutes exposure duration at 4 sites along the aorta) with the UCA Definity (1× concentration, 1 mL/min; Lantheus Medical Imaging, North Billerica, MA) or sham exposed with a saline vehicle injection (n = 12 per group). Four rabbits on the cholesterol diet and 4 on the chow diet served as cage controls and were not exposed to ultrasound or restrained for blood sample collection. Animals were euthanized 24 hours after exposure, and aortas were quickly isolated and frozen in liquid nitrogen. Aorta lysates from the area of ultrasound exposure were analyzed for Hsp70 level by Western blot. Blood plasma was analyzed for cholesterol, Hsp70, and von Willebrand factor, a marker of endothelial function. Plasma total cholesterol levels increased to an average of 705 mg/dL. Ultrasound did not affect plasma von Willebrand factor, plasma Hsp70, or aorta Hsp70. Restraint increased Hsp70 (P < .001, analysis of variance). Restraint, but not ultrasound with the UCA or cholesterol feeding, significantly increased Hsp70.

Symposium 7: Biomarkers of age-related diseases (COST sponsored) S7-1 - CD36 as a biomarker of atherosclerosis

Atherosclerosis is a chronic inflammatory disorder occurs as a result of mononuclear lymphocyte infiltration to the arterial wall accompanied by smooth muscle cell proliferation and damage in the arterial wall caused by extracellular matrix accumulation. Besides several genetic and environmental factors, increased serum cholesterol and oxidized low density lipoproteins are considered to be major risk factors of the disease. During atherosclerosis, lipoproteins such as LDL become trapped at the site of lesion and are converted to oxLDL. Smooth muscle cells become activated by oxLDL, start to proliferate, and migrate into the intima of the arterial wall. OxLDL provokes a cascade of cellular responses at the atherosclerotic lesion, ultimately leading to formation of atherosclerotic plaques. In this process, scavenger receptors could play a critical role because of their ability to bind oxLDL and their function in transporting lipids and cholesterol into and out of the cells. Scavenger receptors are expressed on macrophages and foam cells in atherosclerotic lesions. CD36 is the most important one among them playing role in atherosclerotic process. CD36 is a raft associated glycosylated protein with an 88kDa molecular weight and various ligands such as oxLDL, apoptotic cells, advanced glycation end products bind to this receptor. It has been shown that mice knockouts for the apolipoprotein E exhibited a marked decrease in atherosclerotic lesions if CD36 gene was made inactive. Previously we have shown that the aortas of cholesterol-fed rabbits showed typical atherosclerotic lesions, detected by macroscopic and microscopic examination, and exhibited an increase in CD36 mRNA expression. In this study, we planned to compare CD36 mRNA expressions in the aortic tissue and peripheral blood mononuclear cells in cholesterol induced atherosclerosis. Our results suggests that CD36 mRNA levels in peripheral blood mononuclear cells reflect the levels in aorta and this might be used as a marker for diagnosis of atherosclerosis.

TCT-438 Acute and chronic effects of cryotherapy on atherosclerotic plaque composition in the thoracic aorta of cholesterol-fed rabbits: a potential solution for treatment of plaques

Atherosclerotic plaque rupture remains the leading cause of acute cardiovascular syndromes and the need for plaque stabilizing interventions is high. In the last 10 years, cryotherapy was investigated as a new technology to treat vascular disease. Previous studies focused mainly on treatment and

Effects of vitamin E on peroxisome proliferator-activated receptor γ and nuclear factor-erythroid 2-related factor 2 in hypercholesterolemia-induced atherosclerosis

Atherosclerosis and associated cardiovascular complications such as stroke and myocardial infarction are major causes of morbidity and mortality. We have previously reported a significant increase in mRNA levels of the scavenger receptor CD36 in aortae of cholesterol-fed rabbits and shown that vitamin E treatment attenuated increased CD36 mRNA expression. In the present study, we further investigated the redox signaling pathways associated with protection against atherogenesis induced by high dietary cholesterol and correlated these with CD36 expression and the effects of vitamin E supplementation in a rabbit model. Male albino rabbits were assigned to either a control group fed with a low vitamin E diet alone or a test group fed with a low vitamin E diet containing 2% cholesterol in the absence or presence of daily intramuscular injections of vitamin E (50mg/kg). To elucidate the mechanisms by which vitamin E supplementation alters the effects of hypercholesterolemia in rabbit aortae, we measured peroxisome proliferator-activated receptor γ (PPARγ), ATP-binding cassette transporter A1 (ABCA1), and matrix metalloproteinase-1 (MMP-1) mRNA levels by quantitative RT-PCR and the expression of MMP-1, nuclear factor-erythroid 2-related factor 2 (Nrf2), and glutathione S-transferase α (GSTα) protein by immunoblotting. The increased MMP-1 and decreased GSTα expression observed suggests that a cholesterol-rich diet contributes to the development of atherosclerosis, whereas vitamin E supplementation affords protection by decreasing MMP-1 and increasing PPARγ, GSTα, and ABCA1 levels in aortae of rabbits fed a cholesterol-rich diet. Notably, protein expression of Nrf2, the antioxidant transcription factor, was increased in both the cholesterol-fed and the vitamin E-supplemented groups. Although Nrf2 activation can promote CD36-mediated cholesterol uptake by macrophages, the increased induction of Nrf2-mediated antioxidant genes is likely to contribute to decreased lesion progression. Thus, our study demonstrates that Nrf2 can mediate both pro- and antiatherosclerotic effects.

A novel method for quantifying spatial correlations between patterns of atherosclerosis and hemodynamic factors.

Studies investigating the relation between the focal nature of atherosclerosis and hemodynamic factors are employing increasingly rigorous approaches to map the disease and calculate hemodynamic metrics. However, no standardized methodology exists to quantitatively compare these distributions. We developed a statistical technique that can be used to determine if hemodynamic and lesion maps are significantly correlated. The technique, which is based on a surrogate data analysis, does not require any assumptions (such as linearity) on the nature of the correlation. Randomized sampling was used to ensure the independence of data points, another basic assumption of commonly-used statistical methods that is often disregarded. The novel technique was used to compare previously-obtained maps of lesion prevalence in aortas of immature and mature cholesterol-fed rabbits to corresponding maps of wall shear stress, averaged across several animals in each age group. A significant spatial correlation was found in the proximal descending thoracic aorta, but not further downstream. Around intercostal branch openings the correlation was borderline significant in immature but not in mature animals. The results confirm the need for further investigation of the relation between the localization of atherosclerosis and blood flow, in conjunction with appropriate statistical techniques such as the method proposed here.

TOCOTRIENOLS;

Objective: To evaluate the effect of tocotrienols on intimal thickening in ascending aorta of cholesterol-fed rabbits. StudyDesign: Randomized control trial. Place and duration of study: The Anatomy department of Army Medical College, Rawalpindi, from March2009 to February 2010. Material and Methods: Thirty, male, New Zealand white rabbits were randomly divided into three equal groups. Group-I was fed normal lab diet for six weeks. For the similar period, group-II &amp; III were given 2% high cholesterol diet. However, group-III diet was alsosupplemented with tocotrienols (6 mg/kg body weight/day). By the end of study, aorta was removed from each animal. Cross sections fromascending aorta were processed and embedded in paraffin. Light microscopic examination was performed in H &amp; E and Verhoeff elastic stainedslides. Results: Tunica intima in group-I appeared as single layer of squamous endothelial cells, lying on a thin layer of loose connective tissue.High cholesterol diet in group-II induced marked atherosclerotic changes which were characterized by extensive intimal thickening with raisedfatty streaks, pools of extracellular lipids, proliferation of smooth muscles and deposition of connective tissue matrix. Intimal thickening was alsoobserved in group-III, but lesions were of lesser degree than group-II (P&lt;0.05). Histomorphometric analysis revealed significantly (P&lt;0.001)higher thickness of intima in group-II and in group-III when either was compared with group-I. However, thickness of intima was 35% lesser(P&lt;0.05) in group-III than group-II. Conclusions: Tocotrienols has significant potential in suppressing the intimal thickening of aorta incholesterol-fed rabbits.

Patterns of Sudanophilic Lesions at Ostia of Descending Thoracic and Abdominal Aorta in Cholesterol-Fed Adult Rabbits

Las lesiones ateroscleroticas Sudan-positivas se producen preferentemente en los margenes posteriores y laterales del ostio de las ramas arteriales en neonatos humanos y en conejos destetados, pero tienden a desarrollarse en los margenes laterales y superiores en sujetos de edad avanzada. Investigamos el patron de lesiones sudanofilicas en el ostio aortico de conejos adultos alimentados con colesterol y determinamos las diferencias en la distribucion de lesiones entre la aorta toracica descendente y abdominal. Diez conejos machos blancos adultos New Zealand fueron alimentados con una dieta alta en colesterol al 2%. Despues de seis semanas, fueron extraidas las aortas, se disecaron longitudinalmente y se tineron con Sudan-IV para el examen macroscopico y se observaron las lesiones ateroscleroticas. Fueron examinados 156 ostios de aortas toracicas descendentes y 90 de aortas abdominales. Fueron calculadas y comparadas las frecuencias medias de lesiones superiores, inferiores y de los margenes laterales de los ostios afectados. Las lesiones sudanofilicas se detectaron en alrededor del 32% de ostios de la aorta toracica descendente y en el 25% de las aortas abdominales. En el ostio de la aorta toracica descendente, las frecuencias de lesiones fueron significativamente mayores (p 0,05), pero muy significativa al comparar el margen superior con el inferior (p <0,001). Llegamos a la conclusion que en los conejos adultos alimentados con colesterol, el patron juvenil de deposicion de lipidos por inferior persiste en el ostio de la aorta toracica descendente, mientras que se produce un cambio del modelo en los sujetos de mayor edad hacia superior del ostio de la aorta abdominal.

Blood flow in the rabbit aortic arch and descending thoracic aorta

The distribution of atherosclerotic lesions within the rabbit vasculature, particularly within the descending thoracic aorta, has been mapped in numerous studies. The patchy nature of such lesions has been attributed to local variation in the pattern of blood flow. However, there have been few attempts to model and characterize the flow. In this study, a high-order continuous Galerkin finite-element method was used to simulate blood flow within a realistic representation of the rabbit aortic arch and descending thoracic aorta. The geometry, which was obtained from computed tomography of a resin corrosion cast, included all vessels originating from the aortic arch (followed to at least their second generation) and five pairs of intercostal arteries originating from the proximal descending thoracic aorta. The simulations showed that small geometrical undulations associated with the ductus arteriosus scar cause significant deviations in wall shear stress (WSS). This finding highlights the importance of geometrical accuracy when analysing WSS or related metrics. It was also observed that two Dean-type vortices form in the aortic arch and propagate down the descending thoracic aorta (along with an associated skewed axial velocity profile). This leads to the occurrence of axial streaks in WSS, similar in nature to the axial streaks of lipid deposition found in the descending aorta of cholesterol-fed rabbits. Finally, it was observed that WSS patterns within the vicinity of intercostal branch ostia depend not only on local flow features caused by the branches themselves, but also on larger-scale flow features within the descending aorta, which vary between branches at different locations. This result implies that disease and WSS patterns in the vicinity of intercostal ostia are best compared on a branch-by-branch basis.

Effects of fluvastatin on LDL peroxidation and photon emission of the aorta in cholesterol-fed rabbits

Effects of fluvastatin on LDL peroxidation and photon emission of the aorta in cholesterol-fed rabbits

Sonographic Assessment of Atherosclerotic and Hypercholesterolemic Artery Using the Echo-Tracking Technique in an Animal Model

The purpose of this study was to ascertain the utility of sonography with the echo-tracking (ET) technique to assess vascular stiffness in rabbits with hypercholesterolemia and atherosclerosis. Grayscale sonography associated with the ET technique was used to measure the elastic modulus (Ep) of the aorta in cholesterol-fed rabbits (group T1, n = 44, for 4 weeks; group T2, n = 44, for 12 weeks) and normal control rabbits (group C1, n = 44; group C2, n = 44). The aortic Ep values and blood biochemical markers between groups were compared using analysis of covariance. Light and transmission electron microscopic evaluation were used to demonstrate atherosclerotic changes in the aorta. The Ep values of the aorta in group T1 and T2 rabbits were significantly higher than those of group C1 and C2 controls (88.74 +/- 27.99 and 100.96 +/- 24.81 vs 64.38 +/- 20.23 and 72.35 +/- 18.43, p = .124). Also, the Ep values of the aorta between group T1 and T2 rabbits were significantly different (p = .033). Light and transmission electron microscopy confirmed morphologic typical changes of aortic atherosclerosis in groups T1 and T2. Grayscale sonography with the ET method could be used to evaluate tissue elastic changes in arterial walls associated with atherosclerosis and hypercholesterolemia.

Adipocyte differentiation-related protein is induced by LRP1-mediated aggregated LDL internalization in human vascular smooth muscle cells and macrophages

Aggregated LDL (agLDL) is internalized by LDL receptor-related protein (LRP1) in vascular smooth muscle cells (VSMCs) and human monocyte-derived macrophages (HMDMs). AgLDL is, therefore, a potent inducer of massive intracellular cholesteryl ester accumulation in lipid droplets. The adipocyte differentiation-related protein (ADRP) has been found on the surface of lipid droplets. The objectives of this work were to analyze whether agLDL uptake modulates ADRP expression levels and whether the effect of agLDL internalization on ADRP expression depends on LRP1 in human VSMCs and HMDMs. AgLDL strongly upregulates ADRP mRNA (real-time PCR) and protein expression (Western blot) in human VSMCs (mRNA: by 3.06-fold; protein: 8.58-fold) and HMDMs (mRNA: by 3.5-fold; protein: by 3.71-fold). Treatment of VSMCs and HMDMs with small anti-LRP1-interfering RNA (siRNA-LRP1) leads to specific inhibition of LRP1 expression. siRNA-LRP1 treatment significantly reduced agLDL-induced ADRP overexpression in HMDMs (by 69%) and in VSMCs (by 53%). Immunohystochemical studies evidence a colocolocalization between ADRP/macrophages and ADRP/VSMCs in advanced lipid-enriched atherosclerotic plaques. These results demonstrate that agLDL-LRP1 engagement induces ADRP overexpression in both HMDMs and human VSMCs and that ADRP is highly expressed in advanced lipid-enriched human atherosclerotic plaques. Therefore, LRP1-mediated agLDL uptake might play a pivotal role in vascular foam cell formation.

Endothelial α ν β 3 Integrin–Targeted Fumagillin Nanoparticles Inhibit Angiogenesis in Atherosclerosis

Angiogenic expansion of the vasa vasorum is a well-known feature of progressive atherosclerosis, suggesting that antiangiogenic therapies may stabilize or regress plaques. Alpha(v)beta3 integrin-targeted paramagnetic nanoparticles were prepared for noninvasive assessment of angiogenesis in early atherosclerosis, for site-specific delivery of antiangiogenic drug, and for quantitative follow-up of response. Expression of alpha(v)beta3 integrin by vasa vasorum was imaged at 1.5 T in cholesterol-fed rabbit aortas using integrin-targeted paramagnetic nanoparticles that incorporated fumagillin at 0 microg/kg or 30 microg/kg. Both formulations produced similar MRI signal enhancement (16.7%+/-1.1%) when integrated across all aortic slices from the renal arteries to the diaphragm. Seven days after this single treatment, integrin-targeted paramagnetic nanoparticles were readministered and showed decreased MRI enhancement among fumagillin-treated rabbits (2.9%+/-1.6%) but not in untreated rabbits (18.1%+/-2.1%). In a third group of rabbits, nontargeted fumagillin nanoparticles did not alter vascular alpha(v)beta3-integrin expression (12.4%+/-0.9%; P>0.05) versus the no-drug control. In a second study focused on microscopic changes, fewer microvessels in the fumagillin-treated rabbit aorta were counted compared with control rabbits. This study illustrates the potential of combined molecular imaging and drug delivery with targeted nanoparticles to noninvasively define atherosclerotic burden, to deliver effective targeted drug at a fraction of previous levels, and to quantify local response to treatment.

Vitamin E inhibits CD36 scavenger receptor expression in hypercholesterolemic rabbits

A numerous studies suggest that Vitamin E has a preventive role in atherosclerosis, although the mechanism of action still remains unclear. CD36, a member of the scavenger receptor family is centrally involved in the uptake of oxidized low density proteins (oxLDLs) from bloodstream. During the atherosclerotic process, the lipid cargo of oxLDL accumulates in macrophages and smooth muscle cells, inducing their pathological conversion to foam cells. In the present study, we investigate the role of Vitamin E on CD36 expression in an in vivo model. Atherosclerosis was induced by a 2% cholesterol containing Vitamin E poor diet. Three groups of six rabbits each were studied. The first group (control) was fed on Vitamin E poor diet. The second group was fed with Vitamin E poor diet containing 2% cholesterol and the rabbits in the third group were fed with Vitamin E poor diet containing 2% cholesterol and received injections of 50 mg/kg of Vitamin E i.m. After 4 weeks, aortas were removed and analysed by light microscopy for atherosclerotic lesions. Aortic samples were analysed for CD36 mRNA expression. The aortas of cholesterol-fed rabbits showed typical atherosclerotic lesions, detected by macroscopic and microscopic examination, and exhibited an increase in CD36 mRNA expression. Vitamin E fully prevented cholesterol induced atherosclerotic lesions and the induction of CD36 mRNA expression. The effects observed at the level of CD36 scavenger receptor expression in vivo suggest an involvement of reduced foam cell formation in the protective effect of Vitamin E against atherosclerosis.

Gene transfer using the mature form of VEGF-D reduces neointimal thickening through nitric oxide-dependent mechanism

Gene transfer to the vessel wall using vascular endothelial growth factors (VEGFs) has shown therapeutic potential for the treatment of restenosis. In this study, we evaluated the effect of catheter-mediated adenoviral (Ad) gene transfer of the mature form of VEGF-D (VEGF-D(DeltaNDeltaC)) in balloon-denuded cholesterol-fed rabbit aorta. AdLacZ was used as a control. Transduced VEGF-D(DeltaNDeltaC) mRNA was detectable in the arterial wall with RT-PCR at 6, 14 and 28 days. Gene transfer efficiency as detected with X-gal staining 6 days after the AdLacZ transduction was 1.91 +/- 1.32% in intima. AdVEGF-D(DeltaNDeltaC) gene transfer led to 52% reduction in intima/media ratio (I/M) as compared to the AdLacZ controls at 14 days time point. At 6 days there were no differences in I/M, but the number of macrophages in the vessel wall was 85% lower in the AdVEGF-D(DeltaNDeltaC) group as compared to the controls. The therapeutic effect was no longer detectable 28 days after the gene transfer. The therapeutic effect of VEGF-D(DeltaNDeltaC) was nitric oxide (NO)-dependent as the feeding of NO synthase inhibitor, L-NAME, blocked the reduction in intimal thickening. It is concluded that AdVEGF-D(DeltaNDeltaC) gene transfer reduces intimal thickening and macrophage influx into the vessel wall in balloon-denuded rabbit aortas.

Effect of antiatherogenic l-aspartate and l-glutamate on serum lipoproteins cholesterol and apolipoproteins A-1 and B in rabbits fed with high cholesterol diet

It has been shown that aspartate and glutamate inhibit mononuclear cell adhesion to the endothelium and formation of foam cells in the intima of thoracic aorta in cholesterol-fed rabbits. The purpose of the present study was to investigate whether a high cholesterol diet supplemented with aspartate and glutamate may alter lipoproteins cholesterol and apolipoproteins A-1 and B levels in rabbits. Serum total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglycerides (TG), apolipoprotein A-1 (apoA-1), apolipoprotein B (apoB), atherogenic index (AI) and apoA-1/apoB ratio were determined in 17 male New Zealand white rabbits fed a cholesterol plus corn oil diet (control group) or the same diet supplemented with aspartate and glutamate (Asp+Glu group) for 4 weeks. Both diets were found to increase TC, LDL-C, apoB and AI, while apoA-1/apoB ratio was decreased compared to baseline values. TG did not seem to be affected in the 4 weeks time in both groups. There was a significant increase of HDL-C in Asp+Glu group and a marked decrease of apoA-1 in control group during the study. Oral administration of aspartate and glutamate has been shown to inhibit fatty streak initiation in cholesterol-fed rabbits. The two amino acids did not have any effect on serum TC, LDL-C, TG and apoB concentrations. However, they increased HDL-C and maintained apoA-1 levels. Their antiatherogenic effect probably may be explained by different mechanisms than these related to the atherogenic lipids lowering, and it is possible to involve HDL-C and apoA-1.

Intravascular adenovirus-mediated lipoprotein-associated phospholipase A 2 gene transfer reduces neointima formation in balloon-denuded rabbit aorta

Postangioplasty restenosis is a multifactorial process and involves mechanisms such as inflammation and stimulation of the expression of growth factors. Lipoprotein-associated phospholipase A 2 (Lp-PLA 2) can modify inflammatory responses by hydrolyzing phospholipids with shortened and/or oxidized sn-2 residues. In this study, we tested a hypothesis that adenovirus-mediated Lp-PLA 2 gene transfer can reduce restenosis in rabbits. Aortas of cholesterol-fed NZW rabbits were balloon-denuded and intra-arterial gene transfer was performed using Dispatch catheter with Lp-PLA 2 or LacZ adenoviruses (1.15 × 10 10 pfu). Intima/media ratio (I/M), histology and cell proliferation were analyzed. Two weeks after the gene transfer I/M in the LacZ-transduced control group was 0.45 ± 0.05 but Lp-PLA 2 gene transfer reduced I/M to 0.25 ± 0.03. At four weeks time point I/M in the Lp-PLA 2 group (0.34 ± 0.05) was also lower than in the LacZ group (0.53 ± 0.06). Plasma Lp-PLA 2 activity was increased in the Lp-PLA 2 group (48.2 ± 4.2) as compared to the LacZ group (33.6 ± 3.51) at two weeks time point. Transgene expression was detected in the arterial wall two and four weeks after the procedure. Apoptosis was higher in the control vessels than in the Lp-PLA 2 group at two weeks time point. In conclusion, local adenovirus-mediated Lp-PLA 2 gene transfer resulted in a significant reduction in neointima formation in balloon-denuded rabbit aorta and may be useful for the prevention of restenosis after arterial manipulations.

MMP-12, An Old Enzyme Plays a New Role in the Pathogenesis of Rheumatoid Arthritis?

MMP-12, An Old Enzyme Plays a New Role in the Pathogenesis of Rheumatoid Arthritis?

The effects of coadministration of dietary copper and zinc supplements on atherosclerosis, antioxidant enzymes and indices of lipid peroxidation in the cholesterol‐fed rabbit

It has previously been shown that dietary copper can modulate the extent of atherosclerosis in the thoracic aorta of cholesterol-fed rabbits. The metabolism of copper and zinc are closely related, and it has been hypothesized that the balance of dietary copper to zinc may be important in determining coronary risk. Hence, we have investigated the interaction between dietary copper and zinc in atherogenesis in the New Zealand White rabbit. Juvenile male rabbits were randomly allocated to eight groups. Four groups were fed a normal chow diet with zinc (0.5%, w/w), copper (0.2%, w/w), copper plus zinc or neither in their drinking water for 12 weeks. Four other groups were fed a diet containing 0.25-1% (w/w) cholesterol plus zinc, copper, both or neither. Serum cholesterol of individual animals was maintained at approximately 20 mmol/l. Integrated plasma cholesterol levels were similar for all groups receiving cholesterol and significantly higher than those in the chow-fed groups (P < 0.001). Aortic copper concentrations were higher in the animals receiving cholesterol diets with copper compared to rabbits receiving normal chow and copper (P < 0.001). Aortic zinc content was significantly higher in cholesterol-fed rabbits supplemented with zinc alone or with copper than in those fed cholesterol alone (P < 0.001). Plasma ceruloplasmin concentrations were significantly higher in groups receiving cholesterol, irrespective of their trace element supplementation (P < 0.001). However, trace element supplementation increased the level significantly (P < 0.05). Trace element supplements did not appear to affect erythrocyte superoxide dismutase in the cholesterol-fed animals; however, zinc supplementation was associated with a significant increase in the enzyme in chow-fed animals (P < 0.05). The activity of the enzyme per mg of protein in aortic tissue was higher in animals receiving copper in the presence of cholesterol (P < 0.05) but not significantly so in its absence. Dietary trace element supplementation in cholesterol-fed animals was associated with a significant reduction in aortic lesion area. Plasma thiobarbituric acid-reactive substances and FOX concentrations were both significantly higher in the cholesterol-fed rabbits compared with the animals that fed on a chow diet (P < 0.001), and these were reduced significantly by dietary copper or zinc supplementation (P < 0.001). Hence, dietary supplements of copper or zinc at the doses used both inhibited aortic atherogenesis in the cholesterol-fed rabbits, although there was no significant additional effect when given in combination.