Abstract:In-stent restenosis(ISR) is a significant cause of long-term prognosis after percutaneous coronary intervention (PCI). The inflammatory response is a critical factor in its development. Unlike the chronic inflammatory process of traditional atherosclerosis, ISR may develop acute coronary events within even months or years, and the inflammatory mechanisms of ISR are more complex. Inflammatory factors regulate various mechanisms, including monocyte macrophage proliferation, endothelial cell damage and repair, foam cell formation, and smooth muscle cell proliferation and migration after PCI. The review briefly describes the classification and risk factors of ISR. It emphasizes the role of various inflammatory factors in ISR to provide new ideas for investigating the inflammatory mechanism of ISR and clinical intervention.

Abstract:Aim To investigate the effect of high wall shear stress (WSS) caused by arterio-venous fistula (AVF) on neointimal hyperplasia (NIH) after stent implantation. Methods 36 male New Zealand white rabbits were randomly divided into three groups with 12 rabbits in each group:stent group:right common carotid artery (CCA) stent implantation; stent＋arterio-venous fistula (AVF) group:right CCA stent implantation and right carotid AVF; control group:no treatment. After 21 days, CCA specimen of stent segment was taken for histological staining and protein expression analysis. Results In stent segment CCA, WSS was maintained at 43.2%-48.9% of baseline in stent group, and WSS gradually increased to 86% above baseline level in stent＋AVF group. NIH in stent＋AVF group was less than that in stent group (neointimal area:0.19 mm2 vs. 0.87 mm2; neointima-to-media area ratio:0.18 vs. 1.13). Western blot results showed that the level of endothelial nitric oxide synthase (eNOS) in the stent＋AVF group was significantly higher than that in the stent group, while the levels of proliferating cell nuclear antigen (PCNA), vascular cell adhesion molecule-1 (VCAM-1), phosphorylated p38 mitogen-activated protein kinase (p-p38) and phosphorylated c-Jun NH2-terminal protein kinase (p-JNK) in the stent＋AVF group were significantly lower than those in the stent group. Conclusion High WSS induced by AVF can reduce NIH after stent implantation, and its potential mechanism may be related to the regulation of eNOS, VCAM-1, p38 and JNK expression and activation.

Abstract:Aim To observe the effects of Kindlin-2 RNA interference on intimal hyperplasia in the balloon injured rat carotid arteries. Methods Kindlin-2 siRNA and negative control lentiviral vectors were constructed and produced, then balloon injured rat carotid arteries were infected with lentivirus. Carotid arteries were collected at 1 and 4 weeks after operation. The expression level of Kindlin-2 mRNA in the rat carotid arteries was detected by real-time quantitative PCR technique. The degree of intimal hyperplasia 4 weeks after balloon injury was assessed by HE staining. The immunofluorescence and histochemistry were used to detect the protein expression of Kindlin-2, α-actin, PCNA and β1-integrin in the carotid arteries. The synthesis of collagen fibers in the carotid arteries was investigated by Masson staining. Results Kindlin-2 RNA interference can significantly reduce the Kindlin-2 mRNA expression level in the rat carotid arteries at 1 week(P<0.05), and significantly inhibited intimal hyperplasia of carotid arteries 4 weeks after balloon injury (P<0.05). Compared with the negative control group, the protein expression levels of Kindlin-2, α-actin, PCNA and β1-integrin were significantly decreased in the carotid arteries of the Kindlin-2 group 4 weeks after operation. The synthesis of collagen fibers in the carotid arteries intima and media was also reduced. Conclusion Kindlin-2 RNA interference may inhibit vascular smooth muscle cell proliferation, migration and extracellular matrix synthesis to alleviate intimal hyperplasia.

Abstract:Aim To investigate the effects of OPN-002-siRNA transfection on intimal hyperplasia and osteopontin （OPN）, transforming growth factor-β1 （TGF-β1）, proliferating cell nuclear antigen （PCNA） expression after carotid balloon injury in rat.Methods Through preliminary experiment, OPN mRNA in cultured vascular smooth muscle cells was tested by real-time reverse transcription polymerase chain reaction （real-time RT-PCR）, and OPN-002-siRNA was determined as the most sensitive sequence and used as transfected siRNA in the subsequent animal experiments. Seventy-two rats were randomly divided into four groups: sham group, balloon injury group, OPN-scramble-siRNA （OPN-SCR-siRNA） group and OPN-002-siRNA group. Changes of intimal hyperplasia and OPN, TGF-β1, PCNA expressions were detected by immunofluorescence, hematoxylin-eosin （HE） staining, real-time RT-PCR and Western blot, and also the effect of OPN-002-siRNA was studied on them.Results （1）There was no apparent neointima on the 3rd day after balloon injury. Intima began to thicken on the 7th day after injury, and intimal thickening was significant on the 14th day. （2）The expression of OPN, TGF-β1 mRNA and protein started to increase on the 3rd day and persisted until the 14th day. The expression of PCNA mRNA and protein started to increase on the 3rd day, peaked on the 7th day, decreased on the 14th day. （3）Compared with balloon injury group and OPN-SCR-siRNA group, the neointima thickness decreased significantly on each time point in OPN-002-siRNA group （P<0.001）, and both mRNA and protein expression of OPN, TGF-β1 and PCNA reduced significantly on each time point in OPN-002-siRNA group （P<0.001）.Conclusion OPN-002-siRNA can inhibit intima hyperplasia after artery injury by decreasing the expression of OPN, TGF-β1 and PCNA.

Abstract:Aim To investigate the effect of metformin on intimal hyperplasia after arterial injury and explore the underlying mechanisms. Methods Male SD rats were randomly divided into control group, carotid arterial balloon injury group and carotid arterial balloon injury plus metformin group, 15 rats in each group. After the intervention for three weeks, the histological structure of carotid artery was evaluated by HE staining, the expressions of matrix metalloproteinase （MMP）-2 and MMP-9 were determined by real-time PCR, Western blot and immunohistochemistry staining. Results Intimal hyperplasia was caused by carotid arterial balloon injury. The expressions of MMP-2 and MMP-9 in carotid artery were significantly upregulated after balloon injury （P<0.01）. Treatment of metformin attenuated the upregulation of MMP-2 and MMP-9 and inhibited intimal hyperplasia induced by arterial injury （P<0.05 or P<0.01）. Conclusions Metformin may prevent intimal hyperplasia through inhibiting MMP-2 and MMP-9 expression after arterial injury.

Abstract:Aim To investigate the effects of siRNA recombinant lentivirus targeting CREB binding protein （CBP） gene on neointimal hyperplasia in rat carotid arteries after balloon injury and its possible mechanism. MethodsForty-eight male SD rats were randomly divided into four groups: Sham group, PBS group, CBP-siRNA-Lentivirus group and NC-siRNA-Lentivirus group to establish the model of balloon-injury in left common carotid artery, and the rats were sacrificed 28 days after injury and in vivo gene transfer. The expression of CBP and acetylated nuclear factor kappaB p65 （NF-κB p65） were determined by real-time PCR and Western Blot. Proliferating cell nuclear antigen （PCNA） protein expression was detected by immunohistochemistry. Meanwhile, morphometric analysis was used to measure neointimal hyperplasia. Results 28 days after operations, lentivirus siRNA targeting CBP markedly decreased CBP mRNA and protein expression compared with PBS and NC-siRNA-Lentivirus groups（P<0.05）. CBP gene silencing significantly reduced the neointimal area （0.108±0.008 mm2 vs 0.238±0.022 mm2 and 0.252±0.016 mm2, P<0.05） and intima / media ratio （0.706±0.062 vs 1.483±0.136 and 1.497±0.137, P<0.05）. Furthermore, compared with PBS and NC-siRNA-Lentivirus groups, PCNA and acetylation of NF-κB p65 expression were both obviously downregulated in CBP-siRNA-Lentivirus group （P<0.05）. Conclusions Lentivirus-mediated CBP gene silencing could efficiently suppress neointimal formation in balloon injured rat carotid artery, and the mechanism was involved with downregulation of NF-kB p65 acetylation.

Abstract:AimTo investigate the effects of rosuvastatin on neointimal hyperplasia and mitofusin 2 (Mfn2) expression after carotid artery balloon injury in rats.MethodsThirty-two male Wistar rats were randomly divided into sham-operated group, model group, rosuvastatin group 1 and group 2.The rats in the two rosuvastatin groups were given rosuvastatin 5 mg/kg or 20 mg/kg daily, respectively.The rats in the model group and the two rosuvastatin groups were induced neointimal hyperplasia by carotid artery balloon injury.After the rats were sacrificed at day 14, HE staining was used to observe the change of vascular morphology.Immunohistochemistry staining and Western blot were performed to measure the expression of Mfn2 and proliferating cell nuclear antigen (PCNA).Evans blue staining was used to measure the reendothlialized area.ResultsOn the 14 th day after operation, compared with the model group, the neointimal area and intimal/media area ratio were significantly decreased in the two rosuvastatin groups (P<0.01).Mfn2 expression was up-regulated in the two rosuvastatin groups (P<0.01).Rosuvastatin did not inhibit the reendothlialized in the injured carotid arteries.ConclusionsRosuvastatin attenuates neointimal hyperplasia and restenosis in the rat carotid artery balloon injury model, which may be related to up-regulated expression of Mfn2.

Abstract:Aim To observe the expression of Cyr61 and the effect of atorvastatin on Cyr61 expression in abdominal artery after balloon injury and explore the mechanism of intimal hyperplasia inhibition in injuried arteries by atorvastatin. Methods Intimal hyperplasia was studied by histological morphology method and the expressions of tissue Cyr61 was detected by immunohistochemistry and Western blot at different time-points in abdominal artery of rabbits with balloon injury. Results Intimal hyperplasia was present at day 7 after balloon injury, obvious thickening at day 14 and continue thickening after 28 days, neointimal thickness was uneven, significantly different than that in the control group. The expressions of Cyr61 detected by immunohistochemistry and Western blot increased significantly after balloon injury at day 7 and at day 14, and these results were significantly different from control group （P<0.01）. The expression of Cyr61 decreased significantly after inhibited by atorvastatin at day 7 and at day 14 were significantly different between atorvastatin group and injury group （P<0.01）. There was no significant difference of the expression of Cyr61 between the balloon injury group and atorvastatin group at day 28 （P>0.05）. Conclusions Cyr61 expressed obviously in injury group, but these expressions were inhibited significantly in atorvastatin group. This outcome indicated that Cyr61 may play an important role in intimal hyperplasia. Atorvastatin can inhibit the expression of Cyr61, which suggested that atorvastatin may inhibit intimal hyperplasia by decreasing the expressions of Cyr61.

Abstract:Although arterial conduits are widely used and have improved the long-term results of coronary artery bypass grafting,vein grafts remain important additional conduits in coronary surgery.Newer studies show a saphenous vein graft patency of 60% or more at 10 years postoperatively.Vein graft occlusion occurs as a result of neointimal hyperplasia,which takes place in response to hemodynamic changes,vessel wall injury and thrombosis,and is characterized by the migration and proliferation of vascular smooth muscle cells.Intimal hyperplasia is further complicated by the concomitant development of atherosclerosis.In this review we will summarize the pathogenesis of coronary vein graft disease.

Abstract:Aim To develop a new animal model for the investigation of adventitial function in atherosclerosis.Methods One carotid artery adventitia of rabbit with 2 mg/mL typeII collagenase was digested,then adventitia with microforceps was removed,and the contralateral carotid artery was used as control.HE staining and immunohistochemistry were performed to assure adventitia was removed,and to assess intimal change after adventitial removal.Results It is feasible to remove vascular adventitia with collagenase digestion and mechanical dissection.Removal of adventitia of rabbit carotid artery induced neointima development in 2 weeks.Cells in neointima were secreating smooth muscle cells.The other sides were normal.Conclusions The method we used to remove artery adventitia is effective.Normal adventitia is necessary for normal vessel structure.