Intimal Area Research Articles

Protandim attenuates intimal hyperplasia in human saphenous veins cultured ex vivo via a catalase-dependent pathway

Human saphenous veins (HSVs) are widely used for bypass grafts despite their relatively low long-term patency. To evaluate the role of reactive oxygen species (ROS) signaling in intima hyperplasia (IH), an early stage pathology of vein-graft disease, and to explore the potential therapeutic effects of up-regulating endogenous antioxidant enzymes, we studied segments of HSV cultured ex vivo in an established ex vivo model of HSV IH. Results showed that HSV cultured ex vivo exhibit an ~ 3-fold increase in proliferation and ~ 3.6-fold increase in intimal area relative to freshly isolated HSV. Treatment of HSV during culture with Protandim, a nutritional supplement known to activate Nrf2 and increase the expression of antioxidant enzymes in several in vitro and in vivo models, blocks IH and reduces cellular proliferation to that of freshly isolated HSV. Protandim treatment increased the activity of SOD, HO-1, and catalase 3-, 7-, and 12-fold, respectively, and decreased the levels of superoxide (O 2 •−) and the lipid peroxidation product 4-HNE. Blocking catalase activity by cotreating with 3-amino-1,2,4-triazole abrogated the protective effect of Protandim on IH and proliferation. In conclusion, these results suggest that ROS-sensitive signaling mediates the observed IH in cultured HSV and that up-regulation of endogenous antioxidant enzymes can have a protective effect.

Housefly Maggots (Musca domestica) Protein-enriched Fraction/ extracts (PE) Inhibit Lipopolysaccharide-induced Atherosclerosis Pro-inflammatory Responses

To investigate the effects of housefly maggot (Musca domestica) protein-enriched fraction/extracts (PE) on lipopolysaccharide (LPS)-induced atherosclerosis (AS) pro-inflammatory responses in mice and macrophages. The mouse model of AS was established by feeding a cholesterol-enriched diet and inducing by LPS. Changes in the levels of blood lipids (total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL) and high-density lipoprotein cholesterol (HDL)) and pro-inflammatory cytokines (interferon-gamma (IFNγ), tumor necrosis factor alpha (TNFα) and interleukin-1alpha (IL-1α)) were determined. Histomorphometric analysis of the pathological condition of the artery was also carried out. The macrophages were stimulated by LPS in the presence or absence of PE, and then the levels of TNFα, IL-1α and monocyte chemotactic protein 1 (MCP-1) in cell culture supernatant were measured. Compared with the negative control group, the levels of three pro-inflammatory cytokines were significantly enhanced in the PE treatment group (p< 0.01). The concentrations of TC, TG and LDL were lower in the PE treatment group than in the negative control group (p< 0.01). HDL concentration in the PE treatment group was higher than in the negative control group (p< 0.01). Histomorphometric analysis showed that the thickness of the intima and media area, as well as the area ratio of the intima to media in the PE treatment group were lower than in the negative control group (p< 0.01). The expression of TNFα, IL-1α and MCP-1 in LPS-induced macrophages was inhibited by different concentrations of PE (p< 0.01). These results indicate that PE potently inhibited multiple pro-inflammatory responses in experimental atherosclerosis lesions in vivo, and possessed anti-pro-inflammatory properties in vitro.

Inhibition of intimal hyperplasia after stenting by over-expression of p15: A member of the INK4 family of cyclin-dependent kinase inhibitors

We evaluated the role of p15Ink4, a member of the INK4 family of CDK inhibitors on vascular smooth muscle cells (VSMCs) proliferation, cell cycle progression and intimal hyperplasia after stenting. Aortic VSMCs transduced with either adenovirus encoding for p15Ink4 or β-galactosidase were assessed for DNA synthesis, cell cycle progression, and pRb phosphorylation. Rabbit carotid arteries were stented and treated with peri-adventitial delivery of saline or adenovirus encoding for p15Ink4 or β-galactosidase. p15Ink4 transgene and protein expression were evaluated at 24 h and 72 h, respectively. In-stent cell proliferation was evaluated by BrdU at day 7. Histomorphometric analysis of in-stent intimal hyperplasia was performed at 10weeks. Human p15Ink4 DNA was detected in transduced VSMCs at 24h. p15Ink4 over-expression reduced VSMCs DNA synthesis by 60%. Cell cycle progression was inhibited, with a 30% increase in G1 population accompanied by inhibition of pRb phosphorylation. Human p15Ink4 transgene was identified in transduced stented arteries but not in control arteries. p15Ink4 immunostaining was increased and cell proliferation significantly reduced by 50% in p15Ink4 transduced arteries. Intimal cross-sectional area (CSA) of p15Ink4-treated group was significantly lower than the β-gal treated and non-transduced groups (p=0.008). There were no differences in the intimal or medial inflammatory response between groups. p15Ink4 over-expression blocks cell cycle progression leading to inhibition of VSMCs proliferation. Peri-adventitial delivery of p15Ink4 significantly inhibits in-stent intimal hyperplasia.

Electrical stimulation inhibits neointimal hyperplasia after abdominal aorta balloon injury through the PTEN/p27Kip1 pathway

Electric fields (EFs) exert biological effects on promoting wound healing by facilitating cell division, cell proliferation, and cell directional migration toward the wound. In this study, we examined the inhibitory effect of direct-current (DC) EFs on the formation of neointimal hyperplasia and the possible mechanism in an abdominal aorta balloon injury rabbit model. Sixty rabbits were divided into normal, control, and experimental groups. After establishment of the abdominal aorta balloon injury model, electrodes were implanted into the bilateral psoas major muscle in control and experimental groups. Only the experimental group received electric stimulation (EFs applied at 3 or 4 V/cm for 30 min/day) for 1, 2, and 4 weeks, respectively. Neointimal hyperplasia of the abdominal aorta and proliferation of vascular smooth muscle cells (VSMCs) were measured. Expressions of collagen, p27(Kip1), and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) were detected. Results showed that the ratio of the tunica intima area to the tunica media area, the expression of type-I collagen in the neointimal, and the proliferating cell nuclear antigen index in experimental groups were significantly less than those in control groups 2 weeks post-operation (P< 0.01). Expressions of p27(Kip1) and PTEN were increased in experimental groups compared with control groups (P< 0.01). In conclusion, our results suggested that the application of DC EFs could inhibit neointimal hyperplasia and reduce collagen expression after abdominal aorta balloon injury. This was probably induced by upregulation of PTEN/p27(Kip1) expression, thereby inhibiting VSMC proliferation.

E0710 Is there any anatomic basis for off label use of coronary artery stent in renal artery in swine?

ObjectiveCoronary drug-eluting stents have been implanted in small renal arteries (<5.0 mm) to reduce restenosis. The aim of this study is to investigate the anatomic basis for off label use...

E0073 Effect of bone marrow mesenchymal stem cells transplantation on expression of NFB and PCNA and vascular stenosis after carotid artery balloon injury of rabbit

ObjectiveTo investigate effect of bone marrow mesenchymal stem cells transplantation on expression of nuclear factor κB (NF-κB) and proliferating cell nuclear antigen (PCNA) and vascular stenosis after carotid artery balloon...

E0091 Potential effect of granulocytemacrophage colonystimulating factor on the arterial remodelling at the reference site after angioplasty

ObjectiveArterial remodelling may also occur at the reference site. Resent studies showed that granulocyte-macrophage colony-stimulating factor (GM-CSF) could facilitate the repair of endothelium and reduce vascular inflammation. To observe the...

Topical HDL administration reduces vein graft atherosclerosis in apo E deficient mice

ObjectiveUse of autologous vein grafts for surgical revascularisation is limited by vein graft failure. Topical high-density lipoprotein (HDL) administration on the adventitial side of vein grafts was evaluated as a new therapeutic modality to improve vein graft patency and function. MethodsCaval veins of C57BL/6 apo E−/− mice were grafted to the right carotid arteries of recipient 3 month-old C57BL/6 TIE2-LacZ/apo E−/− mice. HDL (200μg/ml; 50μl) in 20% pluronic F-127 gel was applied on the adventitial side of vein grafts. ResultsTopical HDL application reduced intimal area by 55% (p<0.001) at day 28 compared to control mice. Blood flow quantified by micro magnetic resonance imaging at day 28 was 2.8-fold (p<0.0001) higher in grafts of topical HDL treated mice than in control mice. Topical HDL potently reduced intimal inflammation and resulted in enhanced endothelial regeneration as evidenced by a 1.9-fold (p<0.05) increase in the number of CD31 positive endothelial cells. HDL potently enhanced migration and adhesion of endothelial colony-forming cells (ECFCs) in vitro, and these effects were dependent on signaling via scavenger receptor-BI, extracellular signal-regulated kinases, and NO, and on increased β1 integrin expression. Correspondingly, the number of CD31 β-galactosidase double positive cells, reflecting incorporated circulating progenitor cells, was 3.9-fold (p<0.01) higher in grafts of HDL treated mice than in control grafts. ConclusionsTopical HDL administration on the adventitial side of vein grafts attenuates vein graft atherosclerosis via increased incorporation of circulating progenitor cells in the endothelium, enhanced endothelial regeneration, and reduced intimal inflammation.

Rosiglitazona e lesão vascular em coelhos hipercolesterolêmicos: avaliação da formação neointimal

Rosiglitazone has been the focus of extensive discussion.To evaluate the effects of rosiglitazone on iliac arteries, both at the injury site and the contralateral artery, of hypercholesterolemic rabbits undergoing balloon catheter injury.White male rabbits were fed a hypercholesterolemic diet by oral gavage for 6 weeks and divided into two groups as follows: rosiglitazone group (14 rabbits treated with rosiglitazone during 6 weeks) and the control group (18 rabbits without rosiglitazone). Animals underwent balloon catheter injury of the right iliac artery on the 14th day.In the contralateral iliac artery, there was no significant difference in the intima/media layer area ratio (IMR) between the control and rosiglitazone groups. Rosiglitazone did not reduce the probability of type I, II, or III lesions (72.73% vs 92.31%; p=0.30) and type IV or V lesions (27.27% vs 7.69%; p=0.30). As for the homolateral iliac artery, the intimal area was significantly lower in the rosiglitazone group, as compared to the control group (p = 0.024). The luminal layer area was higher in the rosiglitazone group vs. the control group (p < 0.0001). There was a significant reduction of 65% in the IMR in the rosiglitazone group vs the control group (p = 0.021). None of the histological criteria for type I-V atherosclerotic lesions (American Heart Association) were found in the homolateral iliac artery.These findings demonstrate that rosiglitazone given for 6 weeks prevents atherogenesis at the injury site, but not in a vessel distant from the injury site.

The effects of amiloride, a Na+–H+exchange inhibitor, on iliac artery stenosis after balloon injury in rabbitsThis paper is one of a selection of papers published in this special issue entitled “Second International Symposium on Recent Advances in Basic, Clinical, and Social Medicine” and has undergone the Journal's usual peer review process.

This study was designed to explore the effects of amiloride, a Na+-H+ exchange (NHE) inhibitor, on vessel stenosis by observing the expression of NHE-1 protein in vascular smooth muscle (VSM) after balloon injury and the effects of amiloride on VSM cell proliferation, migration, and excretion of extracellular matrices (ECMs). A total of 32 adult male New Zealand white rabbits were randomly divided into a balloon injury group (BG), an amiloride-treated group (AG), and a sham-operated group (SG). The left iliac artery was injured by inflating a 2.5 mm x 20 mm Foley catheter in BG and AG rabbits; in SG rabbits, the Foley catheter was inserted but not inflated. Amiloride (5 mg x kg(-1) x d(-1)) was injected intraperitoneally in AG and the same volume of distilled water was used in BG 3 days before balloon injury and for 28 days after the injury. The left iliac artery was stained by hematoxylin-eosin, alpha-actin, and Masson's trichrome to observe the vessel cava, neointima, media layer, and ECMs. NHE-1 proteins of the VSM were detected by Western blotting. A narrowing of the arterial cava, neointima formation, and thickened VSM layer were observed 28 days after balloon injury in BG and AG. However, in AG, the vessel cava was not as narrowed as that of BG and the intimal areas were to a lesser extent than in BG. In AG, the alpha-actin-positive areas and the ECM areas in the neointima were increased compared with SG, but to a lesser extent than in BG. The expression of NHE-1 protein in VSM was increased in BG and AG after balloon injury; however, the levels in AG were significantly less than in BG. In conclusion, VSM cell proliferation, migration, and excretion of ECMs contributed to vessel stenosis in the BG and AG rabbits. The expression of NHE-1 protein in VSM increased after balloon injury. Amiloride, an inhibitor of NHE-1, can limit the development of vessel stenosis through inhibition of VSM cell proliferation, migration, and excretion of ECMs.

Multimodal CARS microscopy determination of the impact of diet on macrophage infiltration and lipid accumulation on plaque formation in ApoE-deficient mice

We characterized several cellular and structural features of early stage Type II/III atherosclerotic plaques in an established model of atherosclerosis-the ApoE-deficient mouse-by using a multimodal, coregistered imaging system that integrates three nonlinear optical microscopy (NLOM) contrast mechanisms: coherent anti-Stokes Raman scattering (CARS), second harmonic generation (SHG), and two-photon excitation fluorescence (TPEF). Specifically, the infiltration of lipid-rich macrophages and the structural organization of collagen and elastin fibers were visualized by CARS, SHG, and TPEF, respectively, in thick tissue specimens without the use of exogenous labels or dyes. Label-free CARS imaging of macrophage accumulation was confirmed by histopathology using CD68 staining. A high-fat, high-cholesterol Western diet resulted in an approximate 2-fold increase in intimal plaque area, defined by CARS signals of lipid-rich macrophages. Additionally, analysis of collagen distribution within lipid-rich plaque regions revealed nearly a 4-fold decrease in the Western diet-fed mice, suggesting NLOM sensitivity to increased matrix metalloproteinase (MMP) activity and decreased smooth muscle cell (SMC) accumulation. These imaging results provide significant insight into the structure and composition of early stage Type II/III plaque during formation and allow for quantitative measurements of the impact of diet and other factors on critical plaque and arterial wall features.

International Society for Heart and Lung Transplantation working formulation of a standardized nomenclature for cardiac allograft vasculopathy—2010

The development of cardiac allograft vasculopathy remains the Achilles heel of cardiac transplantation. Unfortunately, the definitions of cardiac allograft vasculopathy are diverse, and there are no uniform international standards for the nomenclature of this entity. This consensus document, commissioned by the International Society of Heart and Lung Transplantation Board, is based on best evidence and clinical consensus derived from critical analysis of available information pertaining to angiography, intravascular ultrasound imaging, microvascular function, cardiac allograft histology, circulating immune markers, non-invasive imaging tests, and gene-based and protein-based biomarkers. This document represents a working formulation for an international nomenclature of cardiac allograft vasculopathy, similar to the development of the system for adjudication of cardiac allograft rejection by histology.

The relative atherogenicity of VLDL and LDL is dependent on the topographic site

To evaluate whether the relative atherogenicity of VLDL and LDL is dependent on the topographic site, atherosclerosis was compared at four topographic sites in homozygous LDL receptor (LDLr)-deficient rabbits fed normal chow and in heterozygous LDLr-deficient rabbits with the same genetic background fed a 0.15% cholesterol diet to match cholesterol levels. VLDL cholesterol was significantly higher and LDL cholesterol significantly lower in LDLr(+/-) diet rabbits compared with LDLr(-/-) rabbits. Intimal area in the ascending thoracic aorta and in the abdominal aorta at the level of the renal arteries was 1.4-fold (P < 0.05) and 1.5-fold (P < 0.05) higher, respectively, in LDLr(-/-) rabbits than in LDLr(+/-) diet rabbits, whereas no significant difference occurred in the descending thoracic aorta and in the abdominal aorta just above the bifurcation. Differences remained statistically significant after adjustment for plasma cholesterol, triglycerides, and sex. Compared with LDLr(+/-) diet rabbits, higher intimal lipoprotein lipase (LPL) and apolipoprotein (apo) B levels were observed in LDLr(-/-) rabbits only at the level of the descending thoracic aorta. Intimal apo E levels in LDLr(-/-) rabbits were significantly lower in sites with a larger intima than in LDLr(+/-) diet rabbits. In conclusion, the relative atherogenicity of VLDL and LDL is dependent on the topographic site.

Enhanced neointimal hyperplasia and carotid artery remodelling in sequestosome 1 deficient mice

Deficiency in the signal adaptor protein sequestosome 1 (SQSTM1/A170/p62) in mice is associated with mature-onset obesity, accompanied by insulin and leptin resistance. We previously established that redox sensitive transcription factor Nrf2 up-regulates SQSTM1 expression in response to atherogenic stimuli or laminar shear stress in vascular cells, and here examine the role of SQSTM1 in neointimal hyperplasia and vascular remodelling in vivo following carotid artery ligation. Neointimal hyperplasia was markedly enhanced at ligation sites after 3 weeks in SQSTM1–/– compared with wild-type (WT) mice. The intimal area and stenotic ratio were, respectively, 2.1- and 1.7-fold higher in SQSTM1−/– mice, indicating enhanced proliferation of vascular smooth muscle cells (SMCs). When aortic SMCs were isolated from WT and SQSTM1−/– mice and cultured in vitro, we found that SQSTM1–/– SMCs proliferated more rapidly in response to foetal calf serum (FCS) and attained 2–3-fold higher cell densities compared to WT SMCs. Moreover, migration of SQSTM1–/– SMCs was enhanced compared to WT SMCs. Early and late phases of p38MAPK activation in response to FCS stimulation were also more enhanced in SQSTM1–/– SMCs, and inhibitors of p38 and ERK1/2 signalling pathways significantly attenuated SMC proliferation. In summary, SQSTM1–/– mice exhibit enhanced neointimal hyperplasia and vascular remodelling following arterial ligation in vivo. The enhanced proliferation of SQSTM1–/– aortic SMCs in vitro highlights a novel role for SQSTM1 in suppressing smooth muscle proliferation following vascular injury.

PS202. Durable Effect of Nitric Oxide at Inhibiting Neointimal Hyperplasia Is due to Modulation of Cellular Populations Throughout the Arterial Wall

We have previously shown that periadventitial delivery of nitric oxide (NO) after arterial injury prevents the development of neointimal hyperplasia; however, the durability of NO-based therapies is unknown. We hypothesize that the effect of NO is durable and due to alteration of cell populations within the arterial wall. The carotid artery balloon injury model was performed on Sprague Dawley rats. Treatment groups included Injury (I) or I+PROLI/NO (20mg). Arteries were harvested at 2 and 8 wks. Neointimal hyperplasia was quantified morphometrically. Van Gieson stain assessed collagen content. Immunohistochemical staining for αSMC actin and desmin assessed smooth muscle cell (SMC) and fibroblast phenotype. NO reduced intimal area (90 and 95%, p < 0.001), medial area (46 and 47%, p < 0.001), and intima/media area ratio (82 and 69%, p < 0.001) at 2 and 8 wks, respectively, with no statistical difference between time points. Qualitatively, NO decreased collagen content compared to I alone. NO reduced total cell number in the arterial wall at 2 and 8 wks (51 and 42%, resp., p < 0.001) by decreasing cell number in the intima (85%, p < 0.001) and media (93%, p < 0.001), but not the adventitia. In fact, adventitial cell count was greater in NO-treated arteries compared to I alone (39% and 54% at 2 and 8 wks, p < 0.001). At 8 wks, an increase in cell number was observed in the adventitia (9%) and media (85%) in the NO-treated arteries compared to the I alone arteries, which was stable. Lastly, SMC markers αSMC actin and desmin were decreased at 2 and 8 wks in NO-treated arteries compared to I alone (52 and 70%, resp., p≤0.009), but this effect was limited to the intima and media. Periadventitial delivery of NO results in durable inhibition of neointimal hyperplasia. Our data suggest that NO reduces collagen content, inhibits repopulation of the media, and inhibits migration of adventitial cells to the intima and media after arterial injury.

A perlecan-inducing compound significantly inhibits smooth muscle cell function and in-stent intimal hyperplasia: novel insights into the diverse biological effects of perlecan

Perlecan is the major heparan sulfate proteoglycan in the arterial wall. Previous studies have suggested that perlecan is a potent inhibitor of smooth muscle cell (SMC) activity. Therefore, perlecan overexpression may serve as a therapeutic modality to prevent in-stent restenosis (ISR). We have investigated a novel compound (RUS3108), identified in a SMC based screen to induce perlecan synthesis in SMC. The aims of this study were to assess the in vitro effects of RUS3108 and the effects of RUS3108-eluting stents in preventing ISR.Rabbit aortic SMC and bovine aortic endothelial cells (EC) were used in this study. Immunohistochemistry showed that RUS3108-treated SMC over-expressed perlecan indicating the drug effects. Furthermore, RUS3108 induced a SMC differentiated phenotype by SMembryonic staining. RUS3108 (1 microM) inhibited 3H-thymidine incorporation by >50%, which was completely reversed by a perlecan antibody. RUS3108 also inhibited SMC migration (Boyden chamber) and MMP-9 activity. In contrast, RUS3108 (100nM) modestly stimulated EC 3H-thymidine incorporation by 22% (p<0.02). In vivo, a total of 30 stents were deployed in rabbit iliac arteries as follows: 1) bare metal stents (n=10), 2) polymer onlycoated stents (n=10), and 3) polymer-coated stents containing RUS3108 (n=10). Rabbits were sacrificed at four weeks and stented segments were subjected to morphometric analysis. Intimal cross sectional area was significantly lower in the RUS3108-eluting stent group (0.31+ or -0.27 mm(2) versus 1.0 + or - 0.31 and 1.25 + or - 0.51 in the bare metal stents and polymer only coated stents groups, respectively, p<0.0001).RUS3108 is a novel perlecan-inducing compound, which is a potent inhibitor of SMC activity and a modest stimulator of EC proliferation. RUS3108-eluting stents may serve as an excellent modality for the prevention of ISR.

Effects of exogenous urotensin II on vascular remodelling after balloon injury

1. Urotensin II (U-II) is a powerful vasoconstrictor peptide that stimulates cell proliferation. However, the systemic effects of U-II on cellular and extracellular matrix responses of vessel walls have not been investigated. The aim of the present study was to determine the effect of exogenous U-II on arterial neointimal hyperplasia after balloon injury. 2. A stenosis model of the thoracic aorta after balloon injury was established in male Wistar rats. Rats were divided into three groups (n = 5 in each): (i) uninjured; (ii) injured for 21 days; and (iii) injured and then treated with U-II (1 nmol/kg per h) via an osmotic minipump for 21 days. Another group of rats were killed on Days 7 and 14 after balloon injury for the analysis of in vitro collagen synthesis and secretion with U-II treated by [(3)H]-proline incorporation and determination of [(3)H]-hydroxyproline radioactivity, respectively. 3. Urotensin II immunoreactivity was 1.74-fold higher in vessels injured for 21 days than in uninjured vessels and mRNA levels of the urotensin UT receptor were upregulated by 55% following injury. After U-II treatment, the mRNA levels of the UT receptor were further upregulated (by 40%). In addition, U-II treatment increased the intimal area of injured aortas (13 +/- 5 vs 7 +/- 2% in group iii and ii, respectively), as well as increasing collagen content and cell proliferation. Protein levels of matrix metalloproteinase 1 were decreased in U-II-treated rats. In vitro, U-II treatment increased collagen synthesis and secretion in uninjured vessels in a concentration-dependent manner (10(-10), 10(-9) and 10(-8) mol/L U-II), especially in injured aortas on Day 7 after injury. 4. In conclusion, exogenous U-II may upregulate mRNA levels of the UT receptor, as well as increase collagen and cell proliferation, all of which would contribute to intimal hyperplasia after angioplasty.

Dietary coenzyme Q10 does not protect against cigarette smoke-augmented atherosclerosis in apoE-deficient mice

Dietary coenzyme Q10 reduces spontaneous atherosclerosis in the apoE-deficient mouse model of experimental atherosclerosis. We have shown previously that exposure to sidestream cigarette smoke (SSCS) enhances atherosclerotic lesion formation in apoE-deficient mice. The aim of the present study was to determine if CoQ10 protected against SSCS-mediated atherosclerosis. Female apoE-deficient mice were fed a saturated fat-enriched diet (SFD) alone, or supplemented with 1% wt/wt coenzyme Q10 (SFD-Q10). Mice in each diet group were exposed to SSCS for 4 hrs/day, 5 days/week in a whole-body exposure chamber maintained at 35 ± 4 mg smoke particulates/m 3. Mice kept in filtered ambient air served as controls. Mice were euthanized after either 6 or 15 weeks of SSCS exposure and following measurements were performed: i) lung 7-ethoxyresorufin-O-deethylase (EROD) activity; ii) plasma cholesterol and CoQ10 concentrations; iii) aortic intimal area covered by atherosclerotic lesions; and, iv) pathological characterization of lesions. Lung EROD activity increased in SSCS mice of both diet groups, confirming SSCS exposure. Plasma concentrations of CoQ10 in SFD-Q10-fed mice were increased markedly in comparison to SFD-fed mice. Plasma cholesterol concentrations and distributions of cholesterol in lipoprotein fractions were unaffected by SSCS exposure. Dietary supplementation with CoQ10 significantly reduced atherosclerotic lesions in control mice. As reported previously, exposure to SSCS increased the size of lesions in apoE-/- mice at both time points. However, dietary supplementation with CoQ10 had no effect on atherosclerotic lesions augmented by SSCS exposure. The results suggest a role of oxidative processes in smoke-augmented atherosclerosis that are different than those mitigated by CoQ10.

Identification of an up-regulated anti-apoptotic network in the internal thoracic artery

BackgroundThe radial artery (RA) is known as an atherosclerosis-prone vessel in contrast to the atherosclerosis-resistant internal thoracic artery (ITA). The purpose of the present study was to compare the gene expression profile of these arteries from the same patient in order to identify genes involved in atherogenesis or intimal hyperplasia. MethodsPaired specimens of RA and ITA (n=6) were analyzed by histomorphometry and whole genome microarray. The microarray data underwent pathway analysis to identify biological networks. Laser microdissection (LMD) was used to identify the cellular expression of candidate genes in the intimal or medial layer of the ITA and RA. ResultsHistomorphometric analyses revealed a significantly higher degree of intimal hyperplasia in the RA compared to the ITA. 552 genes were differentially expressed in the ITA and RA. qRT-PCR confirmed a significant up-regulation of six anti-apoptotic genes. p21 (11.8-fold, p=0.011), CCL2 (5.4-fold, p=0.034), SOCS3 (7.2-fold, p=0.002), IER3 (4.1-fold, p=0.048), MCL-1 (2.6-fold, p=0.025) and IL-6 (17.8-fold, p=0.046) were up-regulated in the ITA. LMD confirmed that cells of the intimal layer of the ITA consistently expressed higher levels of all six candidate genes than those of the RA. ConclusionsMicroarray analysis and qRT-PCR identified significantly up-regulated genes in the ITA involved in an anti-apoptotic network. LMD revealed a higher expression of all anti-apoptotic genes in the intimal area of the ITA. These genes may play an important role in protecting the intima of the ITA from developing hyperplasia and atherosclerosis.

The role of endothelin receptor antagonism in collar-induced intimal thickening and vascular reactivity changes in rabbits

Intimal thickening, due to smooth muscle cell migration and proliferation, is considered to be one of the major components of vascular proliferative disorders such as atherosclerosis and restenosis. One experimental model, resulting in intimal thickening in the rabbit, involves placing a silicon collar around the carotid artery, and is used in this study. Endothelin is known to act as a strong mitogen and to stimulate smooth muscle cell proliferation and migration. We investigated the contribution of endothelin to the development of collar-induced intimal thickening and the effects of TAK-044, (5 mg kg(-1) daily, s.c.), a non-selective ET(A)/ET(B) receptor antagonist, on intimal thickening and vascular reactivity changes in the collared rabbit carotid artery. Endothelin levels and the intimal cross-sectional area, as well as the ratio of intimal area to media (index), increased significantly in collared arteries as compared with those in sham-operated arteries. TAK-044 significantly inhibited intimal thickening and also decreased the index without affecting increased endothelin levels in collared arteries. Vascular reactivity changes in response to collaring produced predictable effects, such as decreased contractile responses to vasoconstrictor agents and increased sensitivity to serotonin (5-hydroxytryptamine, 5-HT). In terms of contractile responses in this model, TAK-044, in particular, did not affect collar-induced vascular reactivity changes. These results suggest that endothelin may be involved in the pathogenesis of collar-induced intimal thickening. As an endothelin receptor antagonist, TAK-044 may potentially be beneficial in the treatment of atherosclerosis.