The lysine methyltransferase SMYD2 facilitates neointimal hyperplasia by regulating the HDAC3-SRF axis

Coronary restenosis is an important cause of poor long-term prognosis in patients with coronary heart disease. Here, we show that lysine methyltransferase SMYD2 expression in the nucleus is significantly elevated in serum- and PDGF-BB-induced vascular smooth muscle cells (VSMCs), and in tissues of carotid artery injury-induced neointimal hyperplasia. Smyd2 overexpression in VSMCs (Smyd2-vTg) facilitates, but treatment with its specific inhibitor LLY-507 or SMYD2 knockdown significantly inhibits VSMC phenotypic switching and carotid artery injury-induced neointima formation in mice. Transcriptome sequencing revealed that SMYD2 knockdown represses the expression of serum response factor (SRF) target genes and that SRF overexpression largely reverses the inhibitory effect of SMYD2 knockdown on VSMC proliferation. HDAC3 directly interacts with and deacetylates SRF, which enhances SRF transcriptional activity in VSMCs. Moreover, SMYD2 promotes HDAC3 expression via tri-methylation of H3K36 at its promoter. RGFP966, a specific inhibitor of HDAC3, not only counteracts the pro-proliferation effect of SMYD2 overexpression on VSMCs, but also inhibits carotid artery injury-induced neointima formation in mice. HDAC3 partially abolishes the inhibitory effect of SMYD2 knockdown on VSMC proliferation in a deacetylase activity-dependent manner. Our results reveal that the SMYD2-HDAC3-SRF axis constitutes a novel and critical epigenetic mechanism that regulates VSMC phenotypic switching and neointimal hyperplasia.

Lesões Plexiformes em Modelo Experimental de Hipertensão Arterial Pulmonar Induzida por Monocrotalina / Plexiform Lesions in an Experimental Model of Monocrotalin-Induced Pulmonary Arterial Hypertension

Resumo Fundamento O modelo de hipertensão arterial pulmonar induzida por monocrotalina (MCT) é um dos mais reproduzidos atualmente, apresentando como limitação a ausência de lesões plexiformes, manifestações típicas da doença grave em humanos. Objetivo Avaliar a gravidade da arteriopatia pulmonar induzida por MCT por meio dos achados anatomopatológicos pulmonares e cardíacos, evolução clínica e sobrevida em 37 dias. Métodos Foram utilizados 50 ratos machos Wistar divididos em quatro grupos, sendo um controle (n = 10). Os três grupos restantes foram submetidos à inoculação de MCT (60 mg/kg i.p.) e ficaram sob o seu efeito por 15 (n = 10), 30 (n = 10) e 37 dias (n = 20). Ao final de cada período, os animais foram sacrificados, obtendo-se tecidos pulmonar e cardíaco para análise anatomopatológica e morfométrica. Empregou-se o teste Kruskal-Wallis, considerando nível de significância de 5%. Resultados Nos pulmões dos animais MCT foram constatadas lesões referentes à arteriopatia pulmonar, incluindo muscularização das arteríolas, hipertrofia da camada média e lesões neointimais concêntricas. Lesões complexas foram observadas nos grupos MCT, descritas como plexiforme e do "tipo" plexiforme (plexiform-like). A hipertrofia do ventrículo direito foi constatada pelo aumento da espessura e diâmetro dos cardiomiócitos e pelo aumento significativo da espessura da parede do ventrículo direito (p<0,0000). Conclusão O modelo foi capaz de gerar arteriopatia pulmonar moderada-grave associada à hipertrofia do ventrículo direito secundária, com sobrevida de 50% em 37 dias. De nosso conhecimento, este estudo foi o primeiro a constatar a presença de lesões vasculares complexas, semelhantes às observadas em pacientes com hipertensão arterial pulmonar grave, em modelo isolado de MCT. (Arq Bras Cardiol. 2020; 115(3):480-490)

Abstract Background The monocrotaline (MCT)-induced pulmonary arterial hypertension model is one of the most reproduced today, presenting as a limitation the absence of plexiform lesions, typical manifestations of the severe disease in humans. Objective To evaluate the severity of MCT-induced pulmonary arteriopathy by pathological findings of lung and heart tissue samples, clinical course and 37-day survival. Methods Fifty male Wistar rats were divided into one of the four groups - control (CG) (n = 10) and three intervention (MCT) groups. The MCT groups received intraperitoneal injection (60 mg/kg) of MCT and remained exposed to the substance for 15 days (G15, n = 10), 30 days (G30, n = 10) and 37 days (G37, n = 20). At the end of each period, the animals were sacrificed, and pulmonary and cardiac tissues were collected for anatomopathological and morphometric analysis. The Kruskal-Wallis test was used, considering a level of significance of 5%. Results In the lungs of MCT animals, lesions related to pulmonary arteriopathy were found, including muscularization of the arterioles, hypertrophy of the middle layer and concentric neointimal lesions. Complex lesions were observed in MCT groups, described as plexiform and plexiform-like lesions. Right ventricular hypertrophy was evidenced by increased thickness and diameter of the cardiomyocytes and a significant increase in the right ventricular wall thickness (p <0.0000). Conclusion The MCT model was able to generate moderate-severe pulmonary arteriopathy associated with secondary right ventricular hypertrophy. The 37-day survival rate was 50%. To our knowledge, this study was the first to note the presence of complex vascular lesions, similar to those observed in patients with severe pulmonary arterial hypertension, in an isolated MCT model. (Arq Bras Cardiol. 2020; 115(3):480-490)

A model of partial ligation of common carotid artery and neointima / 解剖学报

Objective To discuss a method to induce vascular remodeling (intimal regeneration) after partial ligation of the left common carotid artery. Methods Forty 8-week-old male C57BL / 6 J mice were randomly divided into 6 groups: normal group (WT), sham group (sham), 4 weeks, 8 weeks, 10 weeks and 12 weeks postoperative groups. Only the internal carotid, external carotid and occipital arteries in the four distal branches of the left common carotid artery (LCA) were ligated, and the superior thyroid artery was retained, resultsing in intimal neovascularization and vascular remodeling of the left common carotid artery. The changes of body weight and forage were observed after operation. Morphological changes of blood vessels were observed by HE staining. The aggregation of collagen fibers in blood vessels was observed by sirius red staining. Results In addition to the WT group, the weight and dietary quantity of other groups were reduced 1-2 days after the operation, and began to rise from the third day, while the sham group began to rise from the second day. HE staining showed that no new intima was formed in the left common carotid artery of sham group and WT group, and thickening of intima and media layer and stenosis of the nasal cavity were observed in the 4, 8, 10 and 12 weeks groups after partial ligation. There was no intima thickening in the unligated carotid artery on the right side, but there was an enlargement of the lumen. This sirius red stain demonstrated collagen accumulation in the intima and tunica media. Conclution Partial ligation of the left common carotid artery can establish a mouse model of arterial endothelial injury with obvious intima regeneration.

Resultado clínico del tratamiento endovascular con balón liberador de fármaco en el paciente claudicante con enfermedad femoropoplítea / Clinical Outcome of Drug-Eluting Balloon Endovascular Treatment for Femoropopliteal Lesions in Patients with Intermittent Claudication

RESUMEN Introducción: La restenosis continúa siendo el gran desafío de la terapia endovascular, por esa razón, se han desarrollado balones liberadores de fármaco (BLF) con la finalidad de reducir la restenosis. El objetivo de este trabajo es analizar los resultados de esta terapia. Material y métodos: Se realizó un análisis retrospectivo de 40 extremidades de pacientes claudicantes con lesiones femoro-poplíteas tratados con BLF. Resultados: Se obtuvo el éxito técnico en las 40 (100%) extremidades tratadas con una media de seguimiento de 11,1 mes sin evidencia de complicaciones graves relacionadas con el tratamiento con un 92,5% de las extremidades asintomáticas durante el seguimiento. En tres extremidades se realizó una nueva angioplastia por recidiva sintomática. Conclusiones: El BLF ha probado ser una herramienta útil, segura y eficaz para el tratamiento de lesiones de novo y restenosis intrastent; no obstante, en las lesiones TASC C-D se requiere la utilización de un mayor número de stents.

ABSTRACT Background: Restenosis continues to be the great challenge of endovascular therapy, and drug-eluting balloons (DEB) have been developed to reduce it. The aim of this study was to analyze the results of this therapy. Methods: A retrospective analysis of 40 limbs with femoropopliteal lesions treated with DEB was conducted in patients with intermittent claudication. Results: Technical success was obtained in the 40 (100%) limbs treated, without evidence of serious complications related with treatment, and with 92.5% of asymptomatic limbs during the follow-up period of 11.1 months. In three limbs, a new angioplasty was performed due to symptomatic recurrence. Conclusions: The drug-eluting balloon has proven to be a useful, safe and effective tool for the treatment of de novo and in-stent restenosis lesions; however, TASC C-D lesions require the use of greater number of stents.

Randomized Comparison of Strut Coverage between Ticagrelor and Clopidogrel in Acute Myocardial Infarction at 3-Month Optical Coherence Tomography

PURPOSE: This study aimed to compare the effects of ticagrelor and clopidogrel on early neointimal healing assessed with optical coherence tomography (OCT) after drug-eluting stent (DES) implantation in patients with acute myocardial infarction (AMI). MATERIALS AND METHODS: AMI patients were randomly assigned to either the ticagrelor or clopidogrel arm. After DES implantation, OCT was performed to assess the percentages of uncovered struts immediately after procedure and 3 months later. RESULTS: Due to early termination, 83 patients out of 106 initially enrolled patients (24% of planned participants) underwent 3-month OCT. Differences in vascular healing patterns between the two groups, including percentage of uncovered struts on 3-month OCT (9.6% vs. 11.7% in ticagrelor vs. clopidogrel, respectively; p=0.867), neointimal thickness, percentage of malapposed struts, and healing scores did not reach statistical significance. The predictors of uncovered strut on 3-month OCT included greater reference vessel diameter [odds ratio (OR)=1.96, p < 0.001] and more malapposed struts (OR=1.12, p=0.003). CONCLUSION: The current study did not explore favorable effect of ticagrelor on 3-month vascular healing after DES implantation. Our findings should only be considered for generating hypothesis, due to insufficient power.

Inhibitory effect of sustained perivascular delivery of paclitaxel on neointimal hyperplasia in the jugular vein after open cutdown central venous catheter placement in rats

PURPOSE: Inhibitory effect of paclitaxel on neointimal hyperplasia after open cutdown has not been elucidated. METHODS: For the control group (n = 16), silicone 2.7-Fr catheters were placed via the right external jugular vein with the cutdown method. For the treatment group (n = 16), a mixture of 0.65 mg of paclitaxel and 1 mL of fibrin glue was infiltrated around the exposed vein after cutdown. After scheduled intervals (1, 2, 4, and 8 weeks), the vein segment was harvested and morphometric analysis was performed on cross-sections. RESULTS: Proliferation of smooth muscle cell (SMC) was strongly suppressed in the treatment group, and the ratio of neointima to vein wall was significantly reduced in the treatment group (8 weeks; 0.63 ± 0.08 vs. 0.2 ± 0.08, P < 0.05). Luminal patency was significantly more preserved in the treatment group, and the luminal area was significantly wider in the paclitaxel-treated group compared to the control group (8 weeks; 1.91 ± 0.43 mm² vs. 5.1 ± 0.43 mm², P < 0.05). Mean SMC counts measured at 1 and 2 weeks after cutdown were significantly lower in the treatment group (2 weeks; 115 ± 22 vs. 62 ± 22). Paclitaxel was undetectable in systemic circulation (<10 ng/mL). CONCLUSION: Sustained perivascular delivery of paclitaxel with fibrin glue was effective in inhibiting neointimal hyperplasia in rat jugular vein after open cutdown.

The effects of indoxyl sulfate-induced endothelial microparticles on neointimal hyperplasia formation in an ex vivo model

PURPOSE: Neointimal hyperplasia (NH) is considered to be one of the main causes of vascular access occlusion in patients receiving hemodialysis. Endothelial injury and TGF-β-mediated proliferation of vascular smooth muscle cells (VSMCs) induce NH. Endothelial microparticles (EMPs) are also increased by endothelial injury. We aimed to investigate the effects of EMPs and TGF-β expression on VSMC proliferation and their contributions to NH formation in an ex vivo model. METHODS: EMPs were collected from the culture media of human umbilical vein endothelial cells treated with indoxyl sulfate (IS, 250 µg/mL) after ultracentrifugation at 100,000 × g. Porcine internal jugular veins were isolated and treated with EMPs (2 × 10⁶ /mL) or left untreated for 12 days and subsequently compared with TGF-β (10 ng/mL)-treated venous tissue. Intima-media thickness and NH area were assessed using a digital program. Masson's trichrome staining and immunohistochemistry (IHC) analysis for α-smooth muscle actin, phosphorylated Akt, ERK1/2, p38 mitogen-activated protein kinase (MAPK), and Smad3 were performed on each vein sample. RESULTS: NH and VSMC proliferation developed to a significantly greater degree in EMP-treated veins compared to controls, with similar patterns seen in TGF-β-stimulated samples. IHC analysis demonstrated that EMPs markedly increased phosphorylation of Akt, ERK1/2, p38 MAPK, and Smad3 in areas of venous NH formation. CONCLUSION: Our results showed that IS-induced EMPs provoked massive VSMC proliferation and NH formation via activation of the TGF-β signaling pathways. Further investigation is needed to elucidate the precise mechanism of EMP activity on vascular access stenosis in vivo.

Impact of Vascular Injury on Neointimal Hyperplasia in Experimental Rabbit Model / 中国循环杂志

Objective: To study the impact of vascular injury on neointimal hyperplasia and the expressions of nuclear transcription factor-κb (NF-κb), tissue factor (TF), endothelin-1 (ET-1) and matrix metalloproteinase-3 (MMP-3) in experimental rabbit model. Methods:A total of 32 male New Zealand big-eared white rabbits were used to establish vascular injury model by femoral artery puncture, balloon was sent to abdominal aorta via the wire followed by balloon dilatation to strain abdominal aorta. Blood sample was taken from femoral artery sheath 1 minute after operation, and the rabbits were killed at 4 weeks after operation, meanwhile blood sample was taken from the heart. Injured arteries were isolated, ifxed and embedded; slices were stained by HE, basic fuchsine and NF-κb immunohistochemical methods for light microscope observation; slices were also stained by lead and uranium for transmission electron microscope observation. Neointimal thickness was measured by computer analysis, vascular injury integral and NF-κb positive cell rate were determined, blood levels of TF, ET-1 and MMP-3 were examined by ELISA. The relationship between vascular injury integral and the contents of TF, ET-1, MMP-3 and NF-κb positive cell rate were analyzed by SPSS statistical software. Results: The optimal iftting curve between vascular injury integral and neointimal thickness was S-shaped cubic curve. NF-κb was mainly expressed in neointima, vascular injury integral was positively related to NF-κb positive cell percentage, Pearson correlation coeffcient was 0.916,P Conclusion: Vascular injury may activate NF-κb pathway, promote ET-1 and MMP-3 expression, therefore accelerating neointimal hyperplasia, leading negative vascular remodeling, TF was an initiating factor for neointimal hyperplasia. Internal elastic lamina was the key structure reflecting vascular injury, it is the only barrier hindering neointimal hyperplasia in experimental rabbit model.

Effect of cilostazol on neointimal hyperplasia in iliac arteries of pigs after transluminal angioplasty / Efeito do cilostazol na hiperplasia neointimal em artérias ilíacas de suínos submetidas à angioplastia transluminal

OBJECTIVE: To evaluate whether systemic administration of cilostazol reduces neointimal hyperplasia in iliac arteries of pigs submitted to balloon catheter angioplasty. METHODS:Twenty pigs underwent angioplasty with a 6x40 mm balloon catheter in the right common iliac artery, guided by Doppler ultrasound. The animals were randomized into two groups: group 1 (n=10), which received 50mg cilostazol twice a day, and group 2 (n=10), control. After 30 days, the animals were killed and the iliac arteries prepared for histological analysis. The histological sections were digitized and analyzed by digital morphometry. Statistical analysis was performed using the Student t and Mann-Whitney tests. RESULTS:When comparing the iliac arteries submitted to angioplasty with those not subjected to angioplasty, there was significant neointimal hyperplasia (0.228 versus 0.119 mm2; p=0.0001). In arteries undergoing angioplasty, there was no difference between group 1 (cilostazol) and group 2 (control) as for the lumen area (2.277 versus 2.575 mm2; p=0.08), the tunica intima (0.219 versus 0.237 mm2; p=0.64), the tunica media (2.262 vs. 2.393 mm2; p=0.53) and the neointimal occlusion percentage (8.857 vs. 9.257 %; p=0.82). CONCLUSION:The use of cilostazol 50mg administered in two daily doses did not reduce neointimal hyperplasia in iliac arteries of pigs submitted to balloon angioplasty catheter.

OBJETIVO: Avaliar se a administração sistêmica de cilostazol reduz a hiperplasia neointimal nas artérias ilíacas de suínos submetidas à angioplastia com cateter balão. MÉTODOS:Vinte suínos foram submetidos à angioplastia com cateter balão 6x40 mm na artéria ilíaca comum direita, guiada por ultrassonografia com Doppler. Os animais foram randomizados em dois grupos: grupo 1 (n=10), no qual foi administrado cilostazol 50mg em duas doses diárias, e grupo 2 (n=10), considerado controle. Após 30 dias, os animais foram mortos, e as artérias ilíacas preparadas para análise histológica. Os cortes histológicos foram digitalizados e analisados por morfometria digital. A análise estatística foi realizada com o teste t de Student e o de Mann-Whitney. RESULTADOS: Comparando as artérias ilíacas submetidas à angioplastia com as artérias não submetidas à angioplastia, houve hiperplasia neointimal significativa (0,228 versus 0,119 mm2; p=0,0001). Nas artérias submetidas à angioplastia, não houve diferença entre o grupo 1 (cilostazol) e o grupo 2 (controle) na área do lúmen (2,277 versus 2,575 mm2; p=0,08), área da íntima (0,219 versus 0,237 mm2; p=0,64), área da média (2,262 versus 2,393 mm2; p=0,53) e no percentual de obstrução neointimal (8,857 versus 9,257 %; p=0,82).CONCLUSÃO: O uso de cilostazol 50mg administrado em duas doses diárias durante 30 dias não reduziu a hiperplasia neointimal em artérias ilíacas de suínos submetidas à angioplastia com cateter balão.

Effect of imatinib mesylate and rapamycin on the preformed intimal hyperplasia in rat carotid injury model

PURPOSE: Intimal hyperplasia (IH) is the main cause of restenosis or occlusion after vascular procedures. Imatinib mesylate and rapamycin are known to prevent IH. The purpose of this study was to evaluate the effect of these drugs on the regression of preformed IH in rat carotid injury model. METHODS: IH was established in rat carotid arteries using a balloon catheter. The drug effects were assessed in vitro on proliferation, migration, and apoptosis of vascular smooth muscle cells (VSMC) in the neointima. And in vivo studies were carried out in 4 groups: imatinib, rapamycin, combined, and no medication. After 2-week oral medication, morphometric analysis evaluated the number and density of neointimal cells, intima-to-media (I/M) ratio and cross-sectional area. Cell proliferation, apoptosis, and collagen changes were also investigated by immunohistochemical staining (IHCS). RESULTS: Imatinib and rapamycin significantly inhibited VSMC proliferation and migration, and promoted apoptosis in vitro. In morphometric analysis, the number and density of neointimal cells decreased significantly in all medication groups compared with control group (P < 0.01). However, there was no significant difference in neointimal cross-sectional area and I/M ratio among groups. In IHCS, imatinib and rapamycin inhibited neointimal cell proliferation significantly. However, there was no significant change in cell apoptosis and collagen composition. CONCLUSION: Combined treatment of with imatinib and rapamycin induced reduction of cell mass in preformed intimal hyperplasia, but failed to induce regression of intimal mass in this short-term medication study. Further studies will be needed with additional strategies of inducing lysis of the extracellular matrix.

Carbon Monoxide Releasing Molecule Accelerates Reendothelialization after Carotid Artery Balloon Injury in Rat / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>This study was aimed to investigate the effects of carbon monoxide releasing molecule (CORM-2), a novel carbon monoxide carrier, on the reendothelialization of carotid artery in rat endothelial denudation model.</p><p><b>METHODS</b>Male rats subjected to carotid artery balloon injury were treated with CORM-2, inactive CORM-2 (iCORM-2) or dimethyl sulfoxide (DMSO). The reendothelialization capacity was evaluated by Evans Blue dye and the immunostaining with anti-CD31 antibody. The number of circulating endothelial progenitor cells (EPCs) was detected by flow cytometry. The proliferation, migration, and adhesion of human umbilical vein endothelial cells (HUVECs) were assessed by using [3H]thymidine, Boyden chamber and human fibronectin respectively. The expressions of protein were detected by using western blot analysis.</p><p><b>RESULTS</b>CORM-2 remarkably accelerated the re-endothelialization 5 d later and inhibited neointima formation 28 d later. In addition, the number of peripheral EPCs significantly increased in CORM-2-treated rats than that in iCORM-2 or DMSO-treated rats after 5 d later. In vitro experiments, CORM-2 significantly enhanced the proliferation, migration and adhesion of HUVECs. The levels of Akt, eNOS phosphorylation, and NO generation in HUVECs were also much higher in CORM-2 treated group. Blocking of PI3K/Akt/eNOS signaling pathway markedly suppressed the enhanced migration and adhesion of HUVECs induced by CORM-2.</p><p><b>CONCLUSION</b>CORM-2 could promote endothelial repair, and inhibit neointima formation after carotid artery balloon injury, which might be associated with the function changes of HUVECs regulated by PI3K/Akt/eNOS pathway.</p>

Am80 inhibits neointima hyperplasia by promoting interaction of KLF4 with RARα / 中国病理生理杂志

[ ABSTRACT] AIM:To investigate the inhibitory effect of Am80 on neointima hyperplasia in carotid arteries after balloon injury and to observe the interaction between Krüppel-like factor 4 (KLF4) and retinoic acid receptorα(RARα). METHODS:Neointima hyperplasia in carotid arteries was observed by hemotoxylin and eosin staining.The expression of KLF4 and cyclin D1 was examined by immunostaining and Western blotting analysis.To detect the interaction between KLF4 and RARαin the vascular tissue, the injured arteries were harvested, and the protein extracts were prepared and subjected to co-immunoprecipitation assay.RESULTS:Compared with injured group, Am80 significantly reduced neointi-mal hyperplasia and the thickness ratio of intima to media.Am80 not only up-regulated KLF4 or RARαexpression in caro-tid arteries, but also increased the interaction between KLF4 and RARαat tissue levels.CONCLUSION:Am80 inhibits neointima hyperplasia in carotid arteries after balloon injury by promoting the interaction between KLF4 and RARα.

Tissue Responses to Stent Grafts with Endo-Exo-Skeleton for Saccular Abdominal Aortic Aneurysms in a Canine Model

OBJECTIVE: We evaluated the effect of close contact between the stent and the graft on the induction of endothelial covering on the stent graft placed over an aneurysm. MATERIALS AND METHODS: Saccular abdominal aortic aneurysms were made with Dacron patch in eight dogs. The stent graft consisted of an inner stent, a expanded polytetrafluoroethylene graft, and an outer stent. After sacrificing the animals, the aortas with an embedded stent graft were excised. The aortas were inspected grossly and evaluated microscopically. RESULTS: The animals were sacrificed at two (n = 3), six (n = 3), and eight months (n = 2) after endovascular repair. In two dogs, the aortic lumen was occluded at two months after the placement. On gross inspection of specimens from the other six dogs with a patent aortic lumen, stent grafts placed over the normal aortic wall were covered by glossy white neointima, whereas, stent grafts placed over the aneurysmal aortic wall were covered by brownish neointima. On microscopic inspection, stent grafts placed over the normal aortic wall were covered by thin neointima (0.27 +/- 0.05 mm, mean +/- standard deviation) with an endothelial layer, and stent grafts placed over the aneurysmal aortic wall were covered by thick neointima (0.62 +/- 0.17 mm) without any endothelial lining. Transgraft cell migration at the normal aortic wall was more active than that at the aneurysmal aortic wall. CONCLUSION: Close contact between the stent and the graft, which was achieved with stent grafts with endo-exo-skeleton, could not enhance endothelial covering on the stent graft placed over the aneurysms.

The dynamic changes of autophagy in carotid artery after balloon injury in rats / 中国神经精神疾病杂志

Objective To investigate the dynamic levels of autophagy after intimal injury of carotid artery. Meth-ods In this study ,40 male SD rats were randomly assigned to operated(n=20)and control groups(n=20). Balloon inju-ry was induced in the left carotid artery in operated groups .Rats in control groups just received carotid artery exposure without injury. Western blot was used to detect the levels of Beclin-1, LC3 and p62 at the third and seventh days. Immu-nofluorescence was used to examine the expression of Beclin-1 and LC3 at the third and seventh days. Results The ex-pression levels of Beclin-1 and LC3 were increased while the levels of P62 were decreased at the third and seventh days after carotid balloon injury. Beclin-1 and LC3 were present in neointima and medintima. The numbers of both Beclin-1 positive cells and LC3 positive cells were increased at the third and seventh days after carotid injury. The numbers of Be-clin-1 positive cells were 18.60 ± 1.34 in neointima and 6.40 ± 0.55 in medintima at third day, (27.6 ± 2.19 in neointima and 6.40±0.55 in medinitima at the seventh day,(all P=0.000,n=5). The numbers of LC3 positive cells were 10.60±1.52 in neointima and 3.00 ± 0.71 in medintima at third day, (P=0.000,n=5;at the seventh day 21.20 ± 2.49;3.00 ± 0.71,P=0.000,n=5). Conclusions This study domenstrates that autophagy was activated after carotid injury and the chang is dy-namic, which may contribute to neointima formation.

Dissulfeto isomerase proteica como via integrativa entre estresse oxidativo e resposta a proteínas mal-enoveladas na reparação à lesão vascular / Protein disulfide isomerase as an integrative way between oxidative stress and unfolded protein response during vascular repair to injury

O remodelamento vascular é um determinante fundamental do lúmen em doenças vasculares, porém os mecanismos envolvidos não estão completamente elucidados. Nós investigamos o papel da chaperona redox residente do retículo endoplasmático Dissulfeto Isomerase Proteica (PDI) e sua fração localizada na superfície celular (peri/epicelular=pecPDI) no calibre e arquitetura vascular durante reparação à lesão. Em artérias ilíacas de coelho submetidas à lesão in vivo, houve importante aumento do mRNA e expressão proteica (~25x aumento 14 dias pós-lesão vs. controle) da PDI. O silenciamento da PDI por siRNA (cultura de órgãos) acentuou o estresse do retículo e apoptose, diferentemente da inibição da pecPDI com anticorpo neutralizante (PDI Ab). Bloqueio in vivo da pecPDI por aplicação de gel perivascular contendo PDI Ab no 12° dia após lesão, com análise após 48 h, promoveu ca.25% redução no calibre vascular analisado por arteriografia e diminuição similar na área total do vaso detectada por tomografia de coerência óptica. Neste processo, não ocorreu alteração no tamanho da neoíntima, indicando assim, que PDI Ab acentuou remodelamento constrictivo. Neutralização da pecPDI promoveu importantes alterações na arquitetura da matriz de colágeno e citoesqueleto, resultando em fibras com orientação invertida e desorganizadas. Diminuição na produção de espécies reativas de oxigênio e óxidos de nitrogênio também ocorreu. Análise de propriedades viscoelásticas nas artérias indicou redução na ductilidade vascular, evidenciada pela menor distância para ruptura. As alterações subcelulares no citoesqueleto observadas in vivo após PDI Ab foram recapituladas em um modelo de estiramento cíclico em células musculares lisas vasculares, com importante redução na formação das fibras de estresse. Em modelo de migração randômica de células musculares lisas, a exposição a PDI Ab reduziu a resiliência de regulação da polaridade. Embora a neutralização da pecPDI não tenha afetado a atividade...

Whole-vessel remodeling is a critical lumen caliber determinant in vascular disease, but underlying mechanisms are poorly understood. We investigated the role of endoplasmic reticulum chaperone Protein Disulfide Isomerase(PDI) and cell-surface PDI(peri/epicellular=pecPDI) pool in vascular caliber and architecture during vascular repair after injury(AI). After rabbit iliac artery balloon injury, there was marked increase in PDI mRNA and protein (25-fold vs. basal at day 14AI), with increase in both intracellular and pecPDI. Silencing PDI by siRNA (organ culture) induced ER stress augmentation and apoptosis, contrarily to pecPDI neutralization with PDI-antibody(PDI Ab). PecPDI neutralization in vivo with PDIAb-containing perivascular gel from days 12-14AI promoted ca.25% decrease in vascular caliber at arteriography and similar decreases in total vessel circumference at optical coherence tomography, without changing neointima, indicating increased constrictive remodeling. PecPDI neutralization promoted marked changes in collagen and cytoskeleton architecture, with inverted fiber orientation and disorganization. Decreased ROS and nitrogen oxide production also occurred. Viscoelastic artery properties assessment showed decreased ductility, evidenced by decreased distance to rupture. Subcellular cytoskeletal disruption by PDI Ab was recapitulated in vascular smooth muscle cell stretch model, with marked decrease in stress fiber buildup. Also, PDI Ab incubation promoted decreased regulation resilience of vascular smooth muscle migration properties. While pecPDI neutralization did not affect global RhoA activity, there was altered RhoA redistribution to the cell surface and association with caveolin-containing clusters, which mislocalized after stretch. In human coronary atheromas, PDI expression inversely correlated with constrictive remodeling. Thus, strongly-expressed PDI after injury reshapes matrix and cytoskeleton architecture to support an...

Evolução temporal da proliferação neointimal após implante de dois tipos de stent farmacológico com polímeros biodegradáveis em modelo porcino: avaliação qualitativa por tomografia de coerência óptica sequencial / Temporal evolution of neointimal proliferation after implantation of two types of drug-eluting stents with biodegradable polymers in porcine model: qualitative assessment by sequential optical coherence tomography

INTRODUÇÃO: Baseados na hipótese de que a neoíntima encontrada em stents farmacológicos (SFs) com polímeros biodegradáveis aos 28 dias não é a neoíntima definitiva e de que a tomografia de coerência óptica (TCO) é um método eficaz para a avaliação sequencial da neoíntima, objetivamos, neste estudo experimental, comparar os achados da TCO aos 28 dias e aos 90 dias em dois tipos de SF com polímeros biodegradáveis: o stent liberador de sirolimus (Inspiron®, Scitech) e o stent liberador de biolimus A9 (Biomatrix®, Biosensors International). MÉTODOS: No total, 6 porcos não-ateroscleróticos foram submetidos a implante de 6 stents Inspiron® e de 6 stents Biomatrix®. Cada porco recebeu os dois tipos de stent, um em cada artéria coronária (descendente anterior e circunflexa) e após 28 dias e 90 dias foram realizadas avaliações qualitativas intrastent a cada milímetro com TCO. RESULTADOS: A avaliação qualitativa, feita por pareamento milímetro a milímetro intrastent, evidenciou neoíntima heterogênea em 39% aos 28 dias e em 0% aos 90 dias, presença de tecido intraluminal em 18% aos 28 dias e em 0% aos 90 dias, irregularidade luminal em 62% aos 28 dias e em 2% aos 90 dias (P < 0,005). Não houve diferença entre os grupos quanto à qualidade da neoíntima ao longo do tempo (P > 0,05). CONCLUSÕES: Os achados à TCO corroboram a hipótese de que a neoíntima encontrada em SFs com polímeros biodegradáveis aos 28 dias não é a neoíntima definitiva. A evidência experimental mais significativa é a mudança das características da neoíntima observada à TCO sequencial.

BACKGROUND: Based on the hypothesis that the neointima found in drug-eluting stents (DES) with biodegradable polymers at 28 days is not a definitive neointima and that optical coherence tomography (OCT) is an effective method for sequential neointimal evaluation, we aim, in this experimental study, to compare OCT findings at 28 and 90 days, in two different DES with biodegradable polymers: the sirolimus-eluting stent (Inspiron®, Scitech) and the biolimus A9-eluting stent (Biomatrix®, Biosensors International). METHODS: Overall, 6 non-atherosclerotic pigs were submitted to the implantation of 6 Inspiron® stents and 6 Biomatrix® stents. Each pig received both stent types, one in each coronary artery (left anterior descending artery and circumflex artery) and after 28 and 90 days qualitative in-stent OCT analyses were performed at 1-millimeter intervals. RESULTS: Qualitative assessment was performed in-stent pairing millimeter by millimeter. Heterogeneous neointimal tissue was evidenced in 39% at 28 days and in 0% at 90 days, the presence of intraluminal tissue in 18% at 28 days and in 0% at 90 days, luminal irregularity in 62% at 28 days and in 2% at 90 days (P < 0.005). There was no difference between groups regarding the quality of the neointima over time (P > 0.05). CONCLUSIONS: The OCT findings corroborate the hypothesis that the neointima found in DES with biodegradable polymers at 28 days is not a definitive neointima. The most significant experimental evidence is the change in the neointimal characteristics observed at sequential OCT.

Effect of flow diverting stents on the abdominal aorta in rabbits / 中国脑血管病杂志

Objectives: To observe the radiological and pathological changes of flow diverting sent implanting into abdominal aortae of rabbits at 3 months and to evaluate the safety of stents for normal arteries of rabbits. Methods: The abdominal aorta beyond the left renal artery opening was showed via preoperative angiography. The flow diverting stents with metal coverage of 35% to 45% were implanted into the abdominal aortae of 20 New Zealand white rabbits. Intravenous digital subtraction angiography was performed at 4 weeks after the procedure. Arterial digital subtraction angiography was performed for all the animals at 3 months and they were sacrificed for histopathological examination. The angiography showed that the diameter changes of abdominal aortae on the stenting sites at different time points were measured and compared. The relationship between the neointima and the metal coverage of local stent were analyzed. Results: The mean diameter of the abdominal aortae before stenting, immediately after stenting, at 4 weeks, and at 3 months were 3.47 ± 0.44 mm, 3.65 ± 0.40 mm, 3.57 ± 0.36 mm, and 3.51 ± 0.30 mm, respectively. There were significant differences among the different time points (P=0.009). The neointima fully covered the stents with a mean thickness of 95 ± 42 μm. They were predominantly composed of smooth muscle cells, collagen fibers, and a small amount of macrophages. The neointimal thickness was positively correlated with the local coverage of the metal stents (r = 0.523; P = 0.001). Conclusion Three months after the implantation of flow diverting stents, the abdominal aorta intima thickened slightly, and the stents were safety for normal arteries of rabbits.

A Case of In-Stent Neointimal Plaque Rupture 10 Years After Bare Metal Stent Implantation: Intravascular Ultrasound and Optical Coherence Tomographic Findings

Neointimal hyperplasia mainly develops within several months of coronary stent deployment, after which it stabilizes. Although it was widely accepted, particularly during the bare-metal stent (BMS) era, that in-stent restenosis (ISR) generally does not present as an acute coronary syndrome (ACS), but rather as a gradual recurrence of angina symptoms, recent data have shown that a substantial number of patients with ISR present as ACS. There has also been consistent postmortem evidence of plaque rupture secondary to atherosclerotic change within the neointima of a BMS. We report here a case of ACS in which intravascular ultrasound and optical coherent tomographic assessments revealed neointimal atherosclerotic change and ruptured plaque 10 years after BMS deployment.

Late Stent Thrombosis After Drug-Eluting Stent Implantation: A Rare Case of Accelerated Neo-Atherosclerosis and Early Manifestation of Neointimal Rupture

An 80-year old woman suffered from sudden onset of chest pain and dyspnea, and visited the emergency room. She received stent implantation with a biolimus A9-eluting stent (Nobori(R) 3.0x24 mm) at a the mid-portion of the left anterior descending artery 5 months prior to admission. The emergency 5-month follow-up angiogram was performed under the impression of late stent thrombosis. The follow-up angiogram showed subtotal occlusion at the mid-portion of the left anterior descending artery, which was the same segment of previous stent implantation 5 months ago. Immediately after thrombus aspiration with the thrombus aspiration catheter, the optical coherence tomography showed layered appearance of neointimal hyperplasia and neointimal rupture within the previously stented segment. Thus, neointimal rupture within accelerated growth of neointimal tissue was observed within a relatively shorter period (i.e., about 5 months) after stent implantation.

A Case of Neointimal Calcification in a Drug-Eluting Stent / 대한내과학회지

Neointimal hyperplasia is the main mechanism of stent restenosis. Therefore, drug-eluting stents have replaced bare metal stents because there is less neointima and scar formation. Recently, some cases of stent restenosis after using a bare metal stent were found to involve calcification, not neointimal hyperplasia, and regarded as de novo atherosclerosis. We report unusual circular calcification inside a drug-eluting stent, which we called neointimal calcification.