Balloon Injury Of Aorta Research Articles

Desipramine enhances the stability of atherosclerotic plaque in rabbits monitored with molecular imaging.

Acid sphingomyelinase (ASM) promotes atherogenesis and acute cardiovascular events. We previously demonstrated ASM inhibitor desipramine attenuated oxidized-LDL-induced macrophage apoptosis in vitro. Here, we aim to determine whether ASM-mediated apoptosis in plaque improves stability in vivo. In this study, rabbits with abdominal aorta balloon injury and a 12-week high-cholesterol diet (HCD) were used to simulate an atherosclerotic plaque model. Atherosclerotic rabbits received oral administration of saline (Control group), atorvastatin (Ator group), or desipramine (DES group). ASM activity and ceramide level were measured by ultra-performance liquid chromatography (UPLC). Plaque morphology was assessed by histochemistry and immunohistochemistry. Apoptosis was evaluated by SPECT/CT imaging of 99mTc-duramycin uptake and TUNEL. We found that increasing ASM activity and ceramide level in atherosclerotic rabbits was abated by additional atorvastatin and desipramine treatment. Meanwhile, the DES and Ator groups were similar in plaque stability, with smaller plaque size, areas of macrophages, higher smooth muscle cell content, and decreased apoptosis and matrix metalloproteinase (MMP) activities relative to the Control group. 99mTc-duramycin uptake of rabbit aorta was significantly higher in Control than in the Normal group, while it was reduced by desipramine and atorvastatin administration. Moreover, the uptake of 99mTc-duramycin positively correlated with apoptotic cell number, macrophage infiltration, and plaque instability. The present study demonstrated that desipramine exerted plaque-stabilizing effects partially by suppressing apoptosis and MMP activity in a rabbit model. And 99mTc-duramycin SPECT/CT imaging allowed noninvasively monitoring of atherosclerotic disease and evaluation of anti-atherosclerotic therapy.

Double Regulation of Supplement-Detoxification on Diabetic Atherosclerosis by Inhibiting Excessive Autophagy

<i>Objecive</i> To explore the mechanism of Huoxue Jiedu Jiangtang recipe (HJJR) in regulating the hyperactivation of endoplasmic reticulum stress (ERS) autophagy PERK-eIF2a-LC3 pathway, and reveal its prevention for diabetic atherosclerosis. <i>Methods</i> First, the rats were injected with streptozotocin intraperitoneally to make the diabetic models, and then the aortic balloon injury combined with high-fat feeding were used to make the models of atherosclerosis who were randomly divided into model group, western medicine group (Gliquidone + Benazepril), low-dose HJJR group (HJJR₁), high-dose HJJR group (HJJR₂), and accepted corresponding drugs for 8 weeks respectively. Another blank group was used as control. The changes of serum glycosylated hemoglobin (GHb), homocysteine (Hcy) and angiotensinII (Ang1I) were compared. HE staining was used to detect aortic pathology. The mRNA transcription of PRK-like endoplasmic reticulum kinase (PERK), eucaryotic translation initation factor 2α (eIF2α) and CCAAT / Enhance-Binding Protein Homologous Protein (CHOP) were tested by reverse- transcription polymerase chain reaction (RT-PCR). Western blot were used to detect the expression of autophagy activating protein ATG6 (Beclin-1), autophagy protein microtubule-associated protein light chain LC3-1, LC3-II and LC3-II/LC3-I. <i>Results </i>Compared with the model group, after the drug intervention, the aortic tissue injury in each drug group were reduced, and the improvement in the Chinese medicine group was significantly better than that of the western medicine group (P < 0.05). All treatment groups could significantly lowed the levels of serum GHb, Hcy, and Ang1I (P < 0.05), could down regulate the transcription level of PERK, eIF2α and CHOP mRNA (P < 0.05); and decreased the amount of Beclin 1, LC3-II and LC3-II/LC3-1 autophagy protein in aortic cells (P < 0.05). The effect of HJJF group was better, and it was more significant with the increase of HJJF dose. <i>Conclusion</i> HJJR can protect arteries by inhibiting ERS caused by metabolic disorder in diabetes, correcting the homeostasis affecting ER, reducing the overreaction of PERK-eIF2-LC3, and alleviating autophagy effect.

Dipsacoside B Inhibits the Migration and Proliferation of VSMCs and Blunts Neointimal Formation by Upregulating PTEN Expression.

To investigate the effect and potential molecular mechanisms of Dipsacoside B (DB), an herb monomer extracted from Dipsacusasper or Lonicera macranthoides, on the migration and proliferation of vascular smooth muscle cells (VSMCs) and balloon-induced neointimal formation. In vivo, rat abdominal aorta balloon injury model was utilized to investigate the effect of DB on the neointimal formation. In vitro, cultured VSMCs were used to investigate the effect of DB on Angiotensin-II (Ang-II)-induced migration and proliferation of VSMCs. Western blot and immunofluorescence were used to measure PTEN expression. As compared to vehicle control balloon-injury group, DB treatment significantly inhibited the neointimal formation together up-regulated the expression of phosphatase and tension homolog deleted on chromosome 10 (PTEN). Cell proliferations (MTT and Edu incorporation) assays and wound migration measurement further revealed that treatment with DB significantly blunted Ang-II-induced proliferation and migration potential of VSMCs. Western blot analysis exhibited that DB upregulated the expression of PTEN in vivo and in vitro. DB treatment suppresses the proliferation and migration of VSMCs and reduces neointimal formation by the mechanisms involving regulating the phenotype switch of VSMCs via upregulating PTEN expression.

Imaging High-Risk Atherothrombosis Using a Novel Fibrin-Binding Positron Emission Tomography Probe.

High-risk atherosclerosis is an underlying cause of cardiovascular events, yet identifying the specific patient population at immediate risk is still challenging. Here, we used a rabbit model of atherosclerotic plaque rupture and human carotid endarterectomy specimens to describe the potential of molecular fibrin imaging as a tool to identify thrombotic plaques. Atherosclerotic plaques in rabbits were induced using a high-cholesterol diet and aortic balloon injury (N=13). Pharmacological triggering was used in a group of rabbits (n=9) to induce plaque disruption. Animals were grouped into thrombotic and nonthrombotic plaque groups based on gross pathology (gold standard). All animals were injected with a novel fibrin-specific probe 68Ga-CM246 followed by positron emission tomography (PET)/magnetic resonance imaging 90 minutes later. 68Ga-CM246 was quantified on the PET images using tissue-to-background (back muscle) ratios and standardized uptake value. Both tissue-to-background (back muscle) ratios and standardized uptake value were significantly higher in the thrombotic versus nonthrombotic group (P<0.05). Ex vivo PET and autoradiography of the abdominal aorta correlated positively with in vivo PET measurements. Plaque disruption identified by 68Ga-CM246 PET agreed with gross pathology assessment (85%). In ex vivo surgical specimens obtained from patients undergoing elective carotid endarterectomy (N=12), 68Ga-CM246 showed significantly higher binding to carotid plaques compared to a D-cysteine nonbinding control probe. We demonstrated that molecular fibrin PET imaging using 68Ga-CM246 could be a useful tool to diagnose experimental and clinical atherothrombosis. Based on our initial results using human carotid plaque specimens, in vivo molecular imaging studies are warranted to test 68Ga-CM246 PET as a tool to stratify risk in atherosclerotic patients.

Acid Sphingomyelinase Decreases Atherosclerotic Plaque Stability Monitored with Molecular Imaging

Background: Acid sphingomyelinase (ASM) promotes atherogenesis and acute cardiovascular events. We previously demonstrated ASM inhibitor desipramine attenuated oxidized-LDL induced macrophage apoptosis in vitro. Here, we aim to determine whether ASM mediated apoptosis in plaque and improve stability in vivo. Methods: In this study, rabbits with abdominal aorta balloon injury and 12-week high-cholesterol diet (HCD) were used to simulate atherosclerotic plaque model. Atherosclerotic rabbits received oral administration of saline (Control group), atorvastatin (Ator group), or desipramine (DES group). ASM activity and ceramide level were measured by ultra-performance liquid chromatography (UPLC). Plaque morphology was assessed by histochemistry and immunohistochemistry. Apoptosis was evaluated by SPECT/CT imaging of 99mTc-duramycin uptake and TUNEL Results: We found that increasing ASM activity and ceramide level in atherosclerotic rabbits was abated by additional atorvastatin and desipramine treatment. Meanwhile, the DES and Ator groups were similar with regard to plaque stability, with smaller plaque size, areas of macrophages, higher smooth muscle cell content, and decreased apoptosis and matrix metalloproteinase (MMP) activities relative to the Control group. 99mTc-duramycin uptake of rabbit aorta was significantly higher in Control than in Normal group, while it was reduced by desipramine and atorvastatin administration. Moreover, uptake of 99mTc-duramycin positively correlated with apoptotic cell number, macrophage infiltration and plaque instability. Conclusion: The present study demonstrated that desipramine exerted plaque-stabilizing effects partially by suppressing apoptosis and MMP activity in rabbit model. And 99mTc-duramycin SPECT/CT imaging allowed noninvasively monitoring atherosclerotic disease and evaluating anti-atherosclerotic therapy. Funding Information: This work was supported by grants from the National Natural Science Foundation of China (No. 81901784 to ZM, No. 81170261 to ZGG). Declaration of Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Ethics Approval Statement: All animal protocols were approved by the Committee of Animal Care and Use at Xiangya Hospital, Central South University, China. All procedures were conducted to minimize the number of animals used and their suffering.

Quantification of Atherosclerotic Plaque Elasticity Using Ultrasonic Texture Matching

The composition of an atherosclerotic plaque is a major determinant of its vulnerability, i.e. proneness to rupture. This paper proposes an ultrasonic texture matching method, which is shown to reflect the distribution of elastic modulus and is a potential method for quantitatively analyzing different plaque components based on B-mode cine-loops. We performed an in vitro study, employing plaque phantoms fabricated using polyvinyl alcohol. Firstly, the phantoms with two components (soft tissue: 60.9 ± 6.8 kPa; surrounding tissue: 248.8 ± 12.1 kPa) were fabricated. Soft tissue occupied 10%, 40% and 64% of the total plaque volume. Further, three tissue components (soft tissue: 60.9 ± 6.8 kPa; hard tissue: 248.8 ± 12.1 kPa; surrounding tissue: 310.3 ± 14.1 kPa) were made. Soft and hard tissues occupied 32% of total plaque volume, respectively. For our in vivo study, six mice with ApoE knockout and three New Zealand white rabbits with abdominal aortic balloon injury were evaluated. Ultrasound cine-loop data of plaques were collected to calculate elastic modulus, then the plaque tissues were removed for further histology examination. The cine-loop data in vitro study and in vivo study were acquired by an ultrasound micro-imaging system (VisualSonics Vevo2100). In the phantom experiment, the mean elastic moduli of two component phantoms were 60.4 ± 7.6 kPa (soft tissue) and 198.5 ± 12.5 kPa (surrounding tissue), respectively. Similarly, the mean elastic moduli of three component phantoms exhibited 90.2 ± 6.2 kPa (soft tissue), 184.3 ± 11.6 kPa (hard tissue) and 381.6 ± 3.8 kPa (surrounding tissue), respectively. In animal experiments, the percentage of lipid tissue and calcification regions was also quantified in mice and in rabbit experiment with the histological results. This suggests that the texture matching method may be a potential method to identify lipid component of plaque and to predict the vulnerability of atherosclerosis plaques noninvasively.

Fibroblast growth factor-2/platelet-derived growth factor enhances atherosclerotic plaque stability.

Increased immature neovessels contribute to plaque growth and instability. Here, we investigated a method to establish functional and stable neovessel networks to increase plaque stability. Rabbits underwent aortic balloon injury and were divided into six groups: sham, vector and lentiviral transfection with vascular endothelial growth factor‐A (VEGF)‐A, fibroblast growth factor (FGF)‐2, platelet‐derived growth factor (PDGF)‐BB and FGF‐2 + PDGF‐BB. Lentivirus was percutaneously injected into the media‐adventitia of the abdominal aorta by intravascular ultrasound guidance, and plaque‐rupture rate, plaque‐vulnerability index and plaque neovessel density at the injection site were evaluated. Confocal microscopy, Prussian Blue assay, Evans Blue, immunofluorescence and transmission electron microscopy were used to assess neovessel function and pericyte coverage. To evaluate the effect of FGF‐2/PDGF‐BB on pericyte migration, we used the mesenchymal progenitor cell line 10T1/2 as an in vitro model. VEGF‐A‐ and FGF‐2‐overexpression increased the number of immature neovessels, which caused intraplaque haemorrhage and inflammatory cell infiltration, eventually resulting in the plaque vulnerability; however, FGF‐2/PDGF‐BB induced mature and functional neovessels, through increased neovessel pericyte coverage. Additionally, in vitro analysis of 10T1/2 cells revealed that FGF‐2/PDGF‐BB induced epsin‐2 expression and enhanced the VEGF receptor‐2 degradation, which negatively regulated pericyte function consistent with the in vivo data. These results showed that the combination of FGF‐2 and PDGF‐BB promoted the function and maturation of plaque neovessels, thereby representing a novel potential treatment strategy for vulnerable plaques.

Abstract WP526: Molecular Imaging of Carotid Plaques Using a Fibrin-Binding PET Probe

Objectives: We aim to develop molecular fibrin imaging as a tool to stratify high risk atherosclerotic carotid plaques. Here, we describe our results with a fibrin-specific probe [ 68 Ga]CM-246 in two different experimental settings: ex vivo imaging of carotid endarterectomy specimens and in vivo / ex vivo imaging of atherosclerotic plaque rupture in rabbits. Methods: We incubated discarded endarterectomy specimens (n=11) from asymptomatic patients with [ 68 Ga] CM-246 or a scrambled peptide control probe and measured uptake by autoradiography and a tissue binding assay. In a rabbit plaque rupture model of high cholesterol diet followed by abdominal aorta balloon injury (n=13) and subsequent pharmacological plaque rupture, in vivo and ex vivo PET-MR with [ 68 Ga]CM-246 was performed. Tissues were processed for autoradiography and histology to verify presence of fibrin and plaque rupture. Results: Autoradiography (A-B) and tissue binding assays (C) with [ 68 Ga]CM-246 with human carotid plaques show increased tissue binding compared with non-specific control probe. Carstair’s staining (D) verified the presence of fibrin in the specimens (red stained areas). Rabbits with plaque rupture had an increase in [ 68 Ga]CM-246 signal in the abdominal aorta compared with the control group. At 105-120 min post probe injection, there was a clear PET uptake on the aorta in plaque rupture rabbit (E) compared with control rabbit (F). MR images were used to differentiate abdominal aorta (green arrows) and the inferior vena cava (blue arrows). T2-dark blood images confirmed the plaques in rupture (G) and control rabbits (H). ToF images were used to visualize aortic lumen in plaque rupture (I) and control rabbits (J). Ex-vivo PET imaging, autoradiography, and histology confirmed in vivo results. Conclusions: We demonstrated that [ 68 Ga]CM-246 detects high-risk plaque in human and rabbits and can be a useful tool for the stratification of atherosclerotic plaques in patients.

Composition of Ophiopogon Polysaccharide, Notoginseng Total Saponins and Rhizoma Coptidis Alkaloids Inhibits the Myocardial Apoptosis on Diabetic Atherosclerosis Rabbit.

To investigate the effects of Composition of Ophiopogon polysaccharide, Notoginseng total saponins and Rhizoma Coptidis alkaloids (CONR) on myocardial apoptosis of diabetic atherosclerosis (DA) rabbits METHODS: Sixty male New Zealand white rabbits were randomly divided into 6 groups [control group, model group, CONR high-dose group (450 mg/kg), CONR medium-dose group (150 mg/kg), CONR low-dose group (50 mg/kg), and simvastatin group] by using a completely random method, 10 in each group. DA model was established by intravenously injected alloxan combined with high-fat diet and abdominal aortic balloon injury. After mediation for 10 weeks, fasting blood glucose (FBG), glycosylated hemoglobin (GHB), glycosylated serum protein (GSP), fructoseamine (FRA), aldose reductase (AR), advanced glycation end products (AGEs) in serum were measured by enzyme linked immunosorbent assay (ELISA) method; the expression of receptor of AGEs (RAGE) in myocardial tissue were observed by immunohistochemical method; and p-Jun N-terminal kinase (p-JNK), caspase-3, B-cell lymphoma-2 (bcl-2) protein expression in myocardial tissue were measured by Western blotting. The myocardial apoptosis was detected by TdT-mediated dUTPnick-end labeling (TUNEL) method, and apoptosis index (AI) was calculated. Compared with the control group, serum FBG, GHB, GSP, FRA, AR, AGEs and the expression of myocardium RAGE, p-JNK, caspase-3 proteins, as well as apoptosis index (AI) were significantly increased and bcl-2 protein was significantly decreased in the model group (P<0.01). Compared with the model group, the levels of serum FBG, GHB, GSP, FRA and AR showed a significant decline in CONR high- and medium-dose groups (P<0.01). FBG and GHB showed a significant decline in CONR low-dose group (P<0.01). Compared with the model group, the expression of serum AGEs and myocardium RAGE, p-JNK and caspase-3 protein as well as AI were significantly decreased and bcl-2 protein was significantly up-regulated in all treatment groups (P<0.01); high-dose CONR had the most significant effect on abovementioned indices compared with other treatment groups (P<0.01). Middle-dose CONR had better effect on serum AGEs compared with the low-dose group (P<0.01); middle-dose CONR and simvastatin groups had better effect on the expression of caspase-3, bcl-2 protein, myocardium apoptosis compared with the CONR low-dose group (P<0.01). CONR may effectively inhibit myocardial apoptosis on DA rabbits by intervening AGEs-RAGE and JNK, caspase-3, and bcl-2 protein expressions.

Atheroma Susceptible to Thrombosis Exhibit Impaired Endothelial Permeability In Vivo as Assessed by Nanoparticle-Based Fluorescence Molecular Imaging.

The role of local alterations in endothelial functional integrity in atherosclerosis remains incompletely understood. This study used nanoparticle-enhanced optical molecular imaging to probe in vivo mechanisms involving impaired endothelial barrier function in experimental atherothrombosis. Atherosclerosis was induced in rabbits (n=31) using aortic balloon injury and high-cholesterol diet. Rabbits received ultrasmall superparamagnetic iron oxide nanoparticles (CLIO) derivatized with a near-infrared fluorophore (CyAm7) 24 hours before near-infrared fluorescence imaging. Rabbits were then either euthanized (n=9) or underwent a pharmacological triggering protocol to induce thrombosis (n=22). CLIO-CyAm7 nanoparticles accumulated in areas of atheroma (P<0.05 versus reference areas). On near-infrared fluorescence microscopy, CLIO-CyAm7 primarily deposited in the superficial intima within plaque macrophages, endothelial cells, and smooth muscle cells. Nanoparticle-positive areas further exhibited impaired endothelial barrier function as illuminated by Evans blue leakage. Deeper nanoparticle deposition occurred in areas of plaque neovascularization. In rabbits subject to pharmacological triggering, plaques that thrombosed exhibited significantly higher CLIO-CyAm7 accumulation compared with nonthrombosed plaques (P<0.05). In thrombosed plaques, nanoparticles accumulated preferentially at the plaque-thrombus interface. Intravascular 2-dimensional near-infrared fluorescence imaging detected nanoparticles in human coronary artery-sized atheroma in vivo (P<0.05 versus reference segments). Plaques that exhibit impaired in vivo endothelial permeability in cell-rich areas are susceptible to subsequent thrombosis. Molecular imaging of nanoparticle deposition may help to identify biologically high-risk atheroma.

Fimasartan: A New Angiotensin Receptor Blocker.

Fimasartan is the ninth, and most recent, angiotensinII receptor antagonist approved as an antihypertensive agent. Fimasartan, a pyrimidin-4(3H)-one derivative of losartan with the imidazole ring replaced, which enables higher potency and longer duration than losartan. Fecal elimination and biliary excretion are the predominant elimination pathways of fimasartan and the urinary excretion was found to be less than 3% 24h after administration. Fimasartan is primarily catabolized by cytochrome P450 isoform 3A and no significant drug interaction was observed when used in combination with hydrochlorothiazide, amlodipine, warfarin, or digoxin. Fimasartan at a dosage range of 60-120mg once daily showed an antihypertensive effect over 24h. In a large, population-based observational study, fimasartan showed an excellent safety profile. Anti-inflammatory and organ-protecting effects of fimasartan have been shown in various preclinical studies, including aortic balloon injury, myocardial infarct ischemia/reperfusion, doxorubicin cardiotoxicity, and ischemic stroke models.

Optical coherence tomography for serial in vivo imaging of aortic plaque in the rabbit: a preliminary experience

BackgroundIn this pilot feasibility study, we aimed to establish a reproducible means of performing serial optical coherence tomography (OCT) procedures in the abdominal aorta of the cholesterol-fed rabbit.MethodsEight cholesterol-fed New...

Inhibition of intimal hyperplasia via local delivery of vascular endothelial growth factor cDNA nanoparticles in a rabbit model of restenosis induced by abdominal aorta balloon injury.

In-stent restenosis (ISR) is one of the major factors affecting long-term outcomes of percutaneous coronary interventions. Vascular endothelial growth factor (VEGF) has been hypothesized to have a positive role in preventing ISR, however, this remains controversial. The aim of the present study was to assess whether nanoparticles can be used to deliver VEGF to injured arteries and whether this is beneficial in preventing restenosis. New Zealand White rabbits were randomly divided into a control group, an empty nanoparticles group and a VEGF nanoparticles group (n=6 in each group). Polylactic-polyglycolic acid VEGF nanoparticles were prepared using a phacoemulsification method. A rabbit model of restenosis was established following abdominal aorta balloon injury, and VEGF gene nanoparticles, empty nanoparticles or normal saline were delivered locally at the site of injury via a GENIE Catheter™ perfusion balloon. Intimal proliferation determination and immunohistochemistry analysis were performed at day 28 following arterial injury. Compared with the control and empty nanoparticle groups, the neointima area (0.49±0.09, 0.48±0.08 and 0.19±0.11 mm2, respectively; P<0.001) and proliferation index (0.32±0.03, 0.32±0.05 and 0.13±0.06, respectively; P<0.001) were significantly lower in the VEGF nanoparticles group. In addition, in the VEGF nanoparticles group, the immunoreactivity of α-actin and proliferating cell nuclear antigen were significantly lower (P≤0.001), while the immunoreactivity of VEGF was higher (P=0.01). Therefore, the results revealed that local delivery of VEGF gene nanoparticles reduced intimal thickening and cell proliferation following abdominal aorta balloon injury in a rabbit model, demonstrating the efficacy of this therapy against restenosis.

Effect of cystatin C on adventitia in restenosis after rabbit aorta angioplasty

Objective To investigate the effect of cystatin C (Cys C) on adventitia in rabbit abdominal aorta restenosis after angioplasty and its mechanism. Methods 48 New Zealand white rabbits were randomly divided into injury group (receiving balloon dilation of abdominal aorta), the treatment group (taking Cys C monoclonal antibody therapy) and the control group (receiving femoral artery puncture and catheter sheath without balloon dilation and intervention of Cys C monoclonal antibody injection), and each group had 16 rabbits.Peripheral vein blood was drawn to measure the serum level of cystatin C before and 8 h, 1 day, 1 week, 3 weeks, 6 weeks after the operation in all rabbits.After 6 weeks of operation, the abdominal aorta were taken and stained with HE.Vascular morphometry analysis and adventitial cell count were conducted.Smooth muscle actin (SM-actin) and proliferating cell nuclear antigen (PCNA) expressions in the adventitia were observed by immunohistochemical staining.The number of PCNA positive cell in the adventitia was counted and the PCNA proliferation index was calculated.The vascular remodeling index, vascular external elastic lamina area (EELA), internal elastic lamina area (IEIA) were used to evaluate the vascular remodeling and the residual stenosis and vascular cavity area was used to measure the vascular stenosis. Results Plasma Cys C level began to rise at 8h after operation and reached the peak at 1 week after operation, and continuously increased for 5 weeks in injury group, and reached to respectively at 3 weeks and 6 weeks after operation.The Cys C levels were significantly higher in injury group than in the treatment and control groups at different time points (all P<0.05). There were no significant differences in Cys C levels at different time points between the treatment group and the control group.The injury group showed that the number of PCNA positive cells was higher in injury group than in treatment and control groups, both P<0.05). Compared with the control group, the vascular luminal area, EELA and IELA were significantly increased (all P<0.05). After treated with the monoclonal antibody Cys C intervention, the treatment group showed that lumen area, vascular EELA, IELA was significantly decreased (P<0.05), and the vascular remodeling index and residual stenosis rate were decreased as compared with the injury group (0.871 vs.0.784, 33.1% vs.19.7%, both P<0.05). Correlation analysis showed that Cystatin C level was positively correlated with the vascular lumen area, neointimal area, internal elastic lamina area, external elastic lamina area and the number of PCNA positive cells (r=0.812, 0.797, 0.876, 0.932 and 0.822 respectively, all P<0.01). Conclusions Plasma Cys C level is increased in rabbit after abdominal aorta balloon injury and has a positive correlation with the severity of arterial stenosis.High Cys C level can induce adventitial fibroblast activation, proliferation, phenotype transformation and migration, and accelerate the processes of atherosclerosis and stenosis.Cys C level is the independent risk factor for abdominal aortic stenosis. Key words: Cyalones; Aorta, abdominal; Angioplasty

Valsartan decreases neointimal hyperplasia in balloon-injured rat aortic arteries by upregulating HO-1 and inhibiting angiotensin II type 1 receptor

AimsUpregulation of heme oxygenase (HO)-1 plays an important role in vascular protection. Valsartan attenuates neointimal hyperplasia in animal studies. The objective of this study was to examine the role of HO-1 and angiotensin II type 1 (AT1) receptor in the action of valsartan on neointimal hyperplasia in balloon-injured rat aortic arteries. Main methodsThirty-six male Wistar rats were randomly divided into the following three groups with twelve rats in each group: control group, surgery (model) group, and valsartan group. Aortic balloon injury was performed to elicit endothelial denudation with a 2F balloon catheter. On days 14 and 28 after injury, blood was harvested to measure bilirubin levels. Aortic arteries were harvested for morphometry analysis, to determine angiotensin II (Ang II) level, and to analyze mRNA or protein expression. Key findingsCompared with the control group, proliferation and intimal thickening of vascular smooth muscle cells (VSMCs) were obvious in the surgery group rats on days 14 and 28 after injury. Valsartan significantly reduced the proliferation and intimal thickening. Additionally, pretreatment with valsartan significantly reduced Ang II levels, AT1 receptor, and p38 mitogen-activated protein kinase (MAPK) expression. Valsartan increased HO-1 protein and mRNA expression, as well as increased serum bilirubin levels compared with the surgery group. SignificanceValsartan treatment decreased neointimal hyperplasia in balloon-injured rats. The mechanism of action might be linked to the upregulation of HO-1, downregulation of AT1 receptor and inhibition of p38MAPK signal pathway.

Impaired regulator of G protein signaling 2 transcription facilitates vascular remodeling in injured rat aorta.

The activation of Gq-protein-coupled receptors induces proliferation of vascular smooth muscle cells (VSMCs) proliferation and is involved in vascular remodeling. The regulator of G protein signaling 2 (RGS2), which accelerates the termination of Gq protein signaling, may play a role in vascular remodeling. However, this role remains unclear. Aortic balloon injury or sham operation was produced in male Wistar rats. Histological examination and gene expression analysis were performed after surgery. In cultured VSMCs after modulation of RGS2 expression, cell proliferation was also evaluated. At day 3 after injury, RGS2 transcription was reduced by 52.8% (P <0.05 vs. sham group) with vascular remodeling. In cultured VSMCs stimulated by endothelin-1, phenylephrine or angiotensin II, the proliferation of RGS2 overexpressed cells was significantly inhibited; the proliferation of RGS2 downregulated cells was significantly promoted, compared with that of RGS2 normal cells. Moreover, after incubation with angiotensin II of high concentration (>10 μmol/l) or long term (>8 h), the RGS2 expression was clearly downregulated in cultured VSMCs. Administration of an angiotensin receptor blocker, valsartan (20 mg/kg per day) starting from 1 week preballoon injury to 3 days after injury, restored aortic RGS2 transcription and improved vascular remodeling. These results suggested that the inhibiting effect of RGS2 on VSMC proliferation is downregulated in vascular remodeling of injured rat aorta, and this effect is likely to be mediated by angiotensin II signaling.

GW24-e3510 Mechanism of inhibitory effects of C-phycocyanin on over proliferation of vascular smooth muscle cells and luminal stenosis

ObjectivesTo investigate the effects and mechanism of C-phycocyanin (C-PC) from Spirulina Platensis on over proliferation of vascular smooth muscle cells (VSMCs), and endometrial hyperplasia and luminal stenosis after vascular damage.MethodsThe...

Antiatherosclerotic Effects of the Novel Angiotensin Receptor Antagonist Fimasartan on Plaque Progression and Stability in a Rabbit Model

To evaluate the effect of the novel angiotensin receptor blocker Fimasartan on the development of atherosclerosis and plaque stabilization in an animal model. Twenty-four rabbits received an aortic balloon injury from 30 cm to a level just above the aortic valve to the iliac bifurcation using 3 Fr Fogarty catheters on third day of the experiment, followed by a 1% cholesterol diet for 8 weeks. The rabbits were randomized to receive placebo or 3 or 6 mg · kg⁻¹ · d⁻¹ Fimasartan. The study was double blinded. The rabbits started receiving their medications 2 days before the aortic balloon injury and treatment continued. Atherosclerosis burden was determined by calculating the intima-media ratio of the infrarenal portion of the aorta because the bulk of the atherosclerotic burden was limited to the infrarenal region. The frequency of plaque disruption with thrombosis and the proportions of the plaques that were occupied by macrophages, smooth muscle cells, and collagen were determined. Relative to the placebo group, the Fimasartan-treated rabbits had less atherosclerosis [intima-media ratio (mean ± SEM) of 1.14 ± 0.21 vs. 1.51 ± 0.26, P = 0.005], fewer disrupted plaques with thrombi (3 of 16 vs. 5 of 8, P = 0.047), lower proportion of macrophages (17.5% ± 2.5% vs. 26% ± 3.5%, P = 0.03), higher proportion of smooth muscle cells (43.5% ± 8.3% vs. 11.9% ± 2.1%, P = 0.001), and higher proportion of collagen (34.3% ± 6.4% vs. 19.7% ± 2.1%, P = 0.02). These results show that the newly developed angiotensin receptor blocker, Fimasartan, attenuated atherosclerosis progression and reduced macrophage accumulation in the rabbit aortic plaques.

Abstract 151: Thrombosis Prone Plaques Exhibit Inflammation Prior to Rupture: Intravascular Detection via Macrophage-targeted Optical Imaging

Introduction Inflammation modulates atherogenesis and the destabilization of plaques. However, the role of macrophages in plaque rupture is incompletely understood. Here we investigated the in vivo spatial distribution of plaque macrophages prior to triggered plaque rupture, using intravascular molecular imaging and a near-infrared fluorescence (NIRF) macrophage targeted agent, CLIO-CyAm7. We hypothesized that CLIO-CyAm7 would illuminate macrophages in vivo and preferentially localize to plaques that are vulnerable to plaque rupture. Methods Atherosclerosis was induced in rabbits (n=14) using a 12-week hyperlipidemic diet with alternating 1% high cholesterol and normal chow, concomitant with aortic balloon injury at 2 weeks. Rabbits were injected with 2.5mg/kg (n=8) or 5mg/kg (n=6) of CLIO-CyAm7 at 24 or 48 hours, respectively, prior to thrombosis triggering using Russell’s Viper Venom and histamine over 48 hours. The 2.5mg/kg subgroup was imaged in vivo using NIRF imaging and intravascular ultrasound (IVUS), immediately prior to thrombosis triggering. After sacrifice, ex vivo imaging, fluorescence microscopy (FM), Carstairs and Ram-11 immunostaining were performed. Results FM identified significantly higher CLIO-CyAm7 signal in areas of atherosclerosis compared to normal segments of the aorta (2.5mg/kg and 5.0mg/kg, p=0.03 and p=0.03). This signal was primarily localized at the intimal-luminal border of atheroma, with some penetration in the media and adventitia. CLIO-CyAm7 colocalized with a subset of superficial macrophages. Carstairs staining identified fibrin-rich thrombi, indicating plaque rupture in 6 of 14 rabbits (43%). There was increased CLIO-CyAm7 in areas underlying thrombus and particularly at the shoulder of ruptured plaques. Plaque macrophages were detectable via in vivo intravascular NIRF imaging. Areas of atherosclerosis, determined by IVUS, showed significantly higher NIRF peak signal-to-noise ratio than normal segments of the aorta (40.2±16.9 and 5.9±1.9, p=0.02). Conclusion Macrophages are consistently present in plaques that undergo triggered rupture, and can be detected via CLIO-CyAm7 intravascular NIRF molecular imaging. In vivo macrophage imaging may identify thrombosis-prone plaques.

Doxycycline Stabilizes Vulnerable Plaque via Inhibiting Matrix Metalloproteinases and Attenuating Inflammation in Rabbits

Enhanced matrix metalloproteinases (MMPs) activity is implicated in the process of atherosclerotic plaque instability. We hypothesized that doxycycline, a broad MMPs inhibitor, was as effective as simvastatin in reducing the incidence of plaque disruption. Thirty rabbits underwent aortic balloon injury and were fed a high-fat diet for 20 weeks. At the end of week 8, the rabbits were divided into three groups for 12-week treatment: a doxycycline-treated group that received oral doxycycline at a dose of 10 mg/kg/d, a simvastatin-treated group that received oral simvastatin at a dose of 5 mg/kg/d, and a control group that received no treatment. At the end of week 20, pharmacological triggering was performed to induce plaque rupture. Biochemical, ultrasonographic, pathologic, immunohistochemical and mRNA expression studies were performed. The results showed that oral administration of doxycycline resulted in a significant increase in the thickness of the fibrous cap of the aortic plaque whereas there was a substantial reduction of MMPs expression, local and systemic inflammation, and aortic plaque vulnerability. The incidence of plaque rupture with either treatment (0% for both) was significantly lower than that for controls (56.0%, P<0.05). There was no significant difference between doxycycline-treated group and simvastatin-treated group in any serological, ultrasonographic, pathologic, immunohistochemical and mRNA expression measurement except for the serum lipid levels that were higher with doxycycline than with simvastatin treatment. In conclusion, doxycycline at a common antimicrobial dose stabilizes atherosclerotic lesions via inhibiting matrix metalloproteinases and attenuating inflammation in a rabbit model of vulnerable plaque. These effects were similar to a large dose of simvastatin and independent of serum lipid levels.