Induction of tenascin in rat arterial injury. Relationship to altered smooth muscle cell phenotype.

Arterial smooth muscle cells produce large amounts of extracellular matrix molecules during repair processes and in primary culture. This occurs after a transition of the cells from a contractile to a synthetic phenotype and together with the acquisition of proliferative capacity. Here, the deposition of the glycoprotein tenascin in the extracellular matrix of rat arterial smooth muscle cells in vivo and in vitro was studied by immunofluorescence microscopy and immunoblotting. Tenascin was found in the intimal layer of the adult rat aorta and carotid artery, but not in the media. Tenascin also appeared in the neointima formed by proliferating smooth muscle cells 2 weeks after balloon catheter injury of the carotid artery. To determine if the deposition of tenascin in the neointima after arterial injury was related to changes in smooth muscle function, freshly isolated rat aortic smooth muscle cells were seeded on a substrate of plasma fibronectin and allowed to modulate from a contractile to a synthetic state in a serum-free medium. In these quiescent cultures, a tenascin-containing extracellular matrix was formed after 3 to 4 days. Taken together, the results show that tenascin production is induced concomitantly with changes in smooth muscle phenotype both in vivo and in vitro.     

动脉粥样硬化大鼠血管损伤后局部组织学结构的变化

目的建立大鼠颈总动脉球囊损伤模型，了解血管成形术后再狭窄的发生规律及病理机制。方法在大鼠动脉粥样硬化病变的基础上，使用2F球囊导管损伤大鼠左侧颈总动脉，观察术后不同时期内膜、中膜增生的动态改变；对血管壁增殖的细胞进行鉴定；观察血管壁平滑肌细胞表型标志物SMα—actin表达的变化。结果损伤后7天薪生内膜开始形成，至3月时内膜增厚达最大，管腔明显狭窄，损伤动脉壁可见细胞大量增殖，大部分为平滑肌细胞。损伤早期血管壁表达SMα—actin减少，至损伤后期逐渐恢复至原有水平。结论应用球囊导管可以成功建立大鼠血管损伤动物模型，损伤后新生内膜增生导致管腔狭窄，平滑肌细胞的表型改变、迁移及增殖是内膜过度增生的病理基础。     

低浓度脂多糖加速大鼠颈动脉球囊损伤后新生内膜的形成

目的：探讨低浓度脂多糖（LPS）刺激机体免疫系统对血管损伤后加速血管新生内膜增生的影响。方法：选用健康Wistar大鼠，静脉注入LPS后，行颈动脉球囊损伤术，建立血管内膜损伤模型。采用免疫荧光或组织化学染色观察内膜增生变化。Western blot 分析损伤组织特异性平滑肌细胞标志物和细胞凋亡表达。用ELISA测定血清白介素-1β(IL-1β)含量和流式细胞术分析CD14阳性细胞表达水平。结果：每只鼠注入LPS(50 ng)后循环血中单核细胞和IL-1β水平显著升高。血管损伤7 d后中膜平滑肌细胞增殖, 转化为合成表型，新生内膜逐渐形成，随时间延长，内膜增生加速，内膜厚度由(151.2±14.5)μm2增至(173.9±15.3)μm2。免疫荧光染色观察到增殖细胞核抗原及核因子-κB分别定位于新生内膜和外膜。Western blot分析显示新生内膜形成早期LPS组平滑肌特异性标志蛋白α-肌动蛋白多于对照组，caspase-3表达持续上调，细胞凋亡多于对照组。结论：炎症介质LPS刺激全身免疫系统导致血管损伤后新生内膜暂时性增生，表明炎症介质可以加剧血管损伤后再狭窄的形成。     

自体内皮细胞移植在损伤动脉再内皮化及抑制新生内膜增生中的作用

目的:观察自体内皮细胞移植在损伤动脉血管再内皮化及抑制新生内膜增生中的作用。方法: 30只健康雄性纯种新西兰兔行双侧髂股动脉球囊损伤,一侧于损伤后立即经球囊导管行自体静脉内皮细胞移植,另一侧行培养基对照。其中10只动物分别于术后4 h、4 d处死,行扫描电镜检查;5只动物,先将细胞用荧光标记物标记后,再移植入体内,4 d后进行荧光示踪检查;5只动物于术后4 d行Evans blue染色,观察内皮损伤血管段再内皮化情况;其余动物于术后28 d处死,行病理学分析。结果:细胞移植术后4 h,对照组见整个内皮层剥脱,暴露出内皮下弹力膜及平滑肌,细胞移植组则见部分移植内皮已粘附在内皮剥脱血管壁,细胞呈圆形,但尚未铺展;细胞移植术后4 d,移植的内皮已变形,在内皮剥脱血管壁铺展成单层,大量荧光标记内皮细胞被覆在损伤动脉血管内膜;对照组损伤血管几乎完全被Evans blue染成蓝色,细胞移植组损伤血管则60%不被Evans blue着染;病理学分析发现细胞移植组新生内膜面积、最大动脉内膜厚度均显著少于对照组。结论: 自体内皮细胞能有效地经球囊导管移植到内皮损伤血管段,并有减轻新生内膜增生的作用。     

Thrombospondin and other possible related matrix proteins in malignant and benign breast disease. An immunohistochemical study.

Thrombospondin (TSP), which plays an important hemostatic role, is a 450-kd cytoadhesive protein present in the alpha granules of platelets. In vitro experiments using cultured malignant cells suggest that it may help to mediate malignant cell attachment to extracellular matrix and may be important in cancer invasiveness. The authors studied a group of malignant and benign breast tissues for the expression of TSP and provide evidence that TSP may have a role in tumor invasiveness. Using immunohistochemical techniques, the authors found in 48 fresh specimens of breast carcinoma that TSP stained strongly in the desmoplastic stroma or at the basement membrane associated with the malignant ductal epithelium. Tumor cells abutting these tissues revealed cytoplasmic staining for TSP. Stronger TSP staining was seen in the poorly differentiated tumors. These findings were compared with those of normal and benign breast tissue, which showed no TSP staining apart from reactivity in the large distended cysts of fibrocystic disease and faint staining in the stroma of fibroadenomas. Staining for integrin was positive in lymphocytes of both malignant and benign breast disease and equivocally also in the stromal cells of the breast cancer tissue. Immunoreactivity to TSP in tissues was also compared with that of fibronectin, laminin, and collagen type I, III, and IV. The overall findings suggest that thrombospondin may have a role in the tumor biology of invasiveness.     

Vascular wound healing and neointima formation induced by perivascular electric injury in mice.

Vascular interventions for atherothrombotic disease frequently induce neointima formation, which can contribute to restenosis of blood vessels. As the molecular mechanisms of this process remain largely unknown, quantitative models of arterial injury in transgenic animals may be useful to study this process at the genetic level. Here, an injury model is proposed in which surgically exposed femoral arteries in mice were injured perivascularly via a single delivery of an electric current. Transmission electron microscopy, light microscopy, and immunohistochemistry revealed that electric injury destroyed all medial smooth muscle cells, denuded the injured segment of intact endothelium, and transiently induced platelet-rich mural thrombosis. A vascular wound-healing response resulted that was characterized by degradation of the mural thrombus, transient infiltration of the vessel wall by inflammatory cells, and progressive removal of the necrotic debris. Topographic analysis revealed repopulation of the media and accumulation in the neointima of smooth muscle cells originating from the uninjured borders and progressing into the necrotic center. Within 3 weeks after injury, a neointima of 0.026 +/- 0.003 mm2 (n = 7 arteries) was formed that contained a maximum of 12 +/- 1 layers of smooth muscle alpha-actin-immunoreactive cells. Evans blue staining in five electrically injured arteries revealed a denuded distance of 2.8 +/- 0.2 mm immediately after injury, which became progressively re-endothelialized from the uninjured borders to 2.2 +/- 0.08 mm (P = 0.013 vs freshly injured by analysis of variance), 0.8 +/- 0.22 mm (P < 0.001), and 0.005 +/- 0.003 mm (P < 0.001) within 2, 7, and 14 days after injury, respectively. Analysis of 5'-bromo-2'-deoxyuridine incorporation revealed that a maximum of 35 +/- 10% endothelial cells proliferated within 2 days after injury and that in the media and neointima, a maximum of, respectively, 12 +/- 2% and 18 +/- 3% smooth muscle cells proliferated within 2 weeks after injury. Thus, electric injury of arteries provides a model of vascular wound healing with arterial neointima formation and re-endothelialization that may be useful for the genetic analysis of its molecular mechanisms in transgenic mice.     

Role of smooth muscle cell membrane potential in neointima formation in arteries of spontaneously hypertensive rats

Based on observations that vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) have altered resting potentials as well as abnormal cell proliferation rates, neointima formation after controlled balloon injury was compared in arteries from SHR and Wistar Kyoto rats (WKY). SHR aortic VSMC showed hyperpolarized resting membrane potentials (−93±8 mV) when compared to those from WKY (−61±6 mV). Histomorphometric analysis of cross sections from aortic segments submitted to balloon injury showed reduced neointima formation in SHR (neointima/media ratio: 0.04±0.03) as compared to WKY (0.2±0.1). On the other hand, in injured carotid arteries, neointima formation was more extensive in SHR (neointima/media ratio 5.0±0.9) than in WKY (0.8±0.7), leading in most cases to luminal occlusion. Measurements of VSMC resting potential showed that carotid artery cells from SHR were depolarized with respect to those from WKY (−46±4 vs. −69±5 mV, respectively). The results demonstrate an inverse relationship between VSMC membrane polarization and neointima formation in SHR arteries, suggesting that genetic modifications in SHR determine a dysfunctional cellular physiology that may influence cell proliferation subsequent to injury.     

Biochemical analysis of collagen and elastin synthesis in the balloon injured rat carotid artery.

INTRODUCTION: Balloon catheter denudation of the endothelium in the common carotid artery of the rat is routinely used as a model of neointimal lesion development. The response to endothelial denuding injury involves proliferation and migration of medial smooth muscle cells (SMCs), with the formation of a dramatically thickened neointima. While many studies have focused on the kinetics of the early proliferative and migration responses, much less attention has been paid to the pronounced accumulation of extracellular matrix that occurs as the neointima grows. The purpose of this study was to measure collagen and elastin content, and to assess collagen and elastin synthesis in injured rat carotid arteries. METHODS: Male Sprague-Dawley rats were subject to balloon catheter injury of the left carotid artery using a 2F embolectomy catheter. Rats were sacrificed at different time points after injury, and both carotids left (injured) and right (uninjured and control) were used for measurement of elastin and collagen synthesis (7 days) and content (7, 21 and 60 days). RESULTS: Elastin and collagen syntheses were significantly increased in the injured carotids at 7 days after injury. The increase in elastin synthesis was more dramatic (100% compared to control) than the increase in collagen synthesis (50% compared to control). Both elastin and collagen content were significantly increased by 21 days, and contents were further increased by 60 days in the injured carotid compared to uninjured controls. At 60 days, collagen content of the injured vessels was 2.09+/-0.01 mg/arterial segment compared to 1.32+/-0.08 mg/arterial segment in controls (P=.01). Elastin content of injured vessels was 2.40+/-0.43 mg/arterial segment compared to 1.19+/-0.25 mg/arterial segment in controls (P=.03). CONCLUSIONS: Collagen and elastin contents were significantly increased following injury of the rat carotid. This study provides for the first time a biochemical assessment of collagen and elastin in the balloon-injured rat carotid artery.     

Am80通过促进KLF4与维甲酸受体α相互作用抑制血管内膜增生

目的:通过大鼠颈总动脉球囊损伤手术,探讨维甲酸受体α(RARα)激动剂Am80是否通过上调Krüppel样因子4(KLF4)与RARα相互作用而抑制血管新生内膜增生。方法:用球囊损伤大鼠颈总动脉,腹腔注射Am80 14 d后,HE染色观察血管新生内膜增生的情况;通过免疫组化方法检测KLF4和血管壁中cyclin D1的表达;用Western blotting方法检测血管壁中KLF4和RARα的表达,用免疫共沉淀法检测KLF4和RARα的相互作用。结果:与球囊损伤模型组比较,Am80腹腔注射组中,内膜与中膜厚度比率明显降低,KLF4和RARα表达水平升高;而且Am80可以促进损伤血管中KLF4和RARα的相互作用。结论:Am80促进KLF4与RARα的相互作用,从而抑制血管新生内膜的增生。     

Distribution of cellular responses in rabbit aortae following one and two injuries with a balloon catheter.

To investigate the mechanisms involved in the cellular reactions to arterial injuries, we studied the distribution of the deposits on the injured intima and the pattern of neointimal thickening following single and double injuries of rabbit aortae with a balloon catheter. Thirty minutes after the first injury most, but not all, of the inner surface of the aortae was covered by adherent, spread platelets. Seven days following the first injury areas of neointima, mainly proliferating smooth muscle cells, had formed around and opposite the orifices of branch vessels. The rest of the inner aortic surface consisted of acellular subendothelial matrix. Thirty minutes after the second injury, 7 days after the first, single platelets adhered once more to parts of the reinjured subendothelium, mostly between the orifices. Numerous fibrin-rich, platelet thrombi were present mainly on the surface of the injured neointima. Thirty minutes after both the first and second injury polymorphonuclear leucocytes adhered to the inner surface downstream from the orifices of branch vessels and in longitudinally oriented zones opposite the orifices. Four days following the second injury, the neointima was restored with the same distribution as before the second injury, and few thrombi, adherent platelets, or leucocytes remained.     

Distribution of cellular responses in rabbit aortae following one and two injuries with a balloon catheter

To investigate the mechanisms involved in the cellular reactions to arterial injuries, we studied the distribution of the deposits on the injured intima and the pattern of neointimal thickening following single and double injuries of rabbit aortae with a balloon catheter. Thirty minutes after the first injury most, but not all, of the inner surface of the aortae was covered by adherent, spread platelets. Seven days following the first injury areas of neointima, mainly proliferating smooth muscle cells, had formed around and opposite the orifices of branch vessels. The rest of the inner aortic surface consisted of acellular subendothelial matrix. Thirty minutes after the second injury, 7 days after the first, single platelets adhered once more to parts of the reinjured subendothelium, mostly between the orifices. Numerous fibrin-rich, platelet thrombi were present mainly on the surface of the injured neointima. Thirty minutes after both the first and second injury polymorphonuclear leucocytes adhered to the inner surface downstream from the orifices of branch vessels and in longitudinally oriented zones opposite the orifices. Four days following the second injury, the neointima was restored with the same distribution as before the second injury, and few thrombi, adherent platelets, or leucocytes remained.     

The natural history of collagen and alpha-actin expression after coronary angioplasty.

BACKGROUND: Restenosis after percutaneous transluminal coronary angioplasty (PTCA) is a result of remodeling and deposition of new mass. The new mass is formed by invading and replicating cells and by extracellular matrix (ECM), of which collagens constitute the dominating component. Smooth muscle actin is an important element in cell contraction. We tested the hypothesis that the accumulation of collagen and actin correlates with the development of postinjury luminal narrowing. METHODS AND RESULTS: Thirty-five pigs underwent balloon angioplasty and were killed 0, 1, 4, 7, 14, 28, and 56 days later. Tissue samples from the left circumflex artery were in paraffin, sectioned, and immunostained for Collagen Types I and III and alpha1-smooth muscle actin. Collagen accumulation was measured separately in intima, media, and adventitia using computerized semiautomatic planimetry. The injury produced a strong healing response, with a marked accumulation of collagen in all three vessel wall layers. However, the accumulation in adventitia began surprisingly early (1 to 4 days after PTCA) and stopped at Day 7, i.e., before luminal narrowing occurred (14 to 28 days after PTCA in our model). Furthermore, a conspicuous accretion of collagen occurred in the injured area of the medial layer. This response attenuated 14 days after PTCA. Neointimal collagen accumulation took place parallel to neointima formation 2 to 4 weeks after injury. Extramedial smooth muscle actin occurred predominantly from Days 4 to 14 in neointima. Only small quantities of actin were observed in the (neo-)adventitia. Furthermore, adventitial actin was a temporary phenomenon that disappeared between Days 14 and 28. CONCLUSION: Adventitial and medial collagen deposition apparently occurs before luminal narrowing, indicating that the bulk of new mass in adventitia and media is not the cause of vessel remodeling, but possibly stabilizes the vessel wall and impairs compensatory outward remodeling. The accumulation of actin-positive cells and collagen takes place in neointima parallel to luminal narrowing, which suggests that a contraction within the neointimal mass may contribute to the remodeling process.     

Upregulation of collagen VIII following porcine coronary artery angioplasty is related to smooth muscle cell migration not angiogenesis

Type VIII collagen is upregulated after vessel injury, and this collagen has been implicated in both smooth muscle cell migration and angiogenesis. This study examines the temporal and spatial pattern of expression of type VIII collagen in porcine coronary vessels at specific time points after balloon angioplasty. In situ hybridization studies demonstrated that collagen VIII messenger ribonucleic acid (mRNA) was markedly elevated in the neoadventitia at 3 days post-angioplasty. By 14 days, elevated collagen VIII message was seen mainly in the neointima and this expression decreased to background levels by 90 days. The distribution of collagen VIII protein, detected using immunohistochemistry, was similar but the up-regulation lagged behind the mRNA increase by a few days. Pre-treatment of sections with pepsin highlighted variations in the organization and appearance of extracellular collagen VIII containing structures in both injured and normal vessels.New vessel formation was evident in the neoadventitia after 3 days, but there was no colocalization of type VIII collagen immunostaining with that of von Willebrand factor (a marker of endothelial cells) in the neoadventitia.These data show that up-regulation of collagen VIII in the neoadventitia is an important early marker of the coronary arterial response to injury, and is not associated with new vessel formation.     

Colocalization of thrombospondin and syndecan during murine development.

Thrombospondin is an adhesive glycoprotein that is thought to play a role in tissue genesis and repair. We have used a monoclonal anti-thrombospondin antibody, designated 5G11, to localize thrombospondin in paraformaldehyde fixed, paraffin-embedded sections of developing mouse embryos. Thrombospondin expression is observed in uterine smooth muscle, endometrial glands, the decidua, and trophoblastic giant cells during the initial phase of post-implantation development in the embryo. Cardiac myocytes and neuroepithelial cells show positive staining for thrombospondin at day 8.5 of gestation, and this expression continues throughout the development of the myocardium and central nervous system. Strong staining for thrombospondin is seen in developing bone and in the liver. Thrombospondin is also observed in developing smooth muscle and skeletal muscle, as well as in a variety of epithelia, including the epidermis, small intestinal epithelium, lens epithelium, renal tubular epithelium, and the epithelium of the developing tooth. Comparison of thrombospondin staining with that of two known cell surface receptors for thrombospondin, syndecan and the vitronectin receptor, reveals remarkable colocalization of thrombospondin and syndecan in all tissues, but almost no coexpression with the vitronectin receptor. Coexpression of thrombospondin and syndecan may play an important role in cell-cell or cell-matrix interactions during development.     

粒细胞集落刺激因子对大鼠颈动脉球囊损伤后再内皮化和内膜增生过程的影响

目的：探讨重组人粒细胞集落刺激因子对大鼠颈总动脉球囊损伤后再内皮化和内膜增生过程的影响。方法:56只Wistar大鼠随机分为2组,重组人粒细胞集落刺激因子（商品名：瑞白）+损伤组（rhG-CSF预防组）(n=28):皮下注射瑞白30 μg/kg，每日1次，共7 d后，行左颈总动脉球囊拉伤,术后1 h（n=4）、3 d(n=4)、5 d(n=4)、7 d(n=5)、14 d(n=6)取材;生理盐水+损伤组(NS+损伤组)(n=28):皮下注射生理盐水0.5 mL,同上时点取材。应用扫描电镜、伊文氏蓝染色、HE染色、免疫组织化学的方法,观察颈总动脉损伤后再内皮化、新生内膜增厚及细胞增殖的情况。通过RT-PCR检测血管壁内皮型一氧化氮合酶（eNOS）mRNA表达。结果:重组人粒细胞集落刺激因子可明显增加损伤血管内皮的修复面积、抑制新生内膜形成，增加了血管壁eNOS mRNA表达 。结论：重组人粒细胞集落刺激因子对大鼠颈总动脉球囊损伤血管再内皮化和内膜增生过程有血管重塑作用。     

EXPRESSION OF THE MULTIFUNCTIONAL EXTRACELLULAR MATRIX PROTEIN THROMBOSPONDIN IN CRESCENTIC GLOMERULONEPHRITIS

Thrombospondin is a multifunctional 450 kD glycoprotein which may be secreted into the extracellular matrix by a wide variety of cells. Occasional foci of immunoreactive thrombospondin have previously been demonstrated within normal human glomeruli. A specific polyclonal antibody directed against thrombospondin 1 was used to examine the distribution of this regulatory glycoprotein in renal biopsies from patients with a variety of renal diseases, including rapidly progressive glomerulonephritis associated with circulating antibodies to neutrophils, active or quiescent systemic lupus erythematosus, and membranous nephropathy, together with normal renal tissue. The results demonstrated the marked up-regulation of thrombospondin expression in acutely inflamed renal tissue with strongly positive, predominantly extracellular staining of glomerular crescents, although cytoplasmic staining of epithelial cells was also seen, indicating that these cells may contribute to thrombospondin accumulation at these sites. Occasional segmental mesangial staining was seen in cases of active lupus and rapidly progressive glomerulonephritis, while some focal interstitial staining around peritubular capillaries was seen in all renal tissue examined. These results suggest that thrombospondin may play an important role in the regulation of cellular recruitment, proliferation, and function in crescentic glomerulonephritis.     

Mechanisms of restenosis after coronary intervention: difference between plain old balloon angioplasty and stenting.

BACKGROUND: Restenosis after coronary intervention remains an unsolved and important clinical problem. We histologically examined the mechanism of restenosis after both balloon injury and stenting. METHODS: Coronary arteries of swine were subjected to balloon injury and stenting. Next, just after stenting or at 7, 14, or 28 days, the animals were sacrificed for the evaluation by morphometric analysis, histological observation, and immunostaining. RESULTS: The neointimal area peaked at 14 days in the balloon injury group (BG) and increased linearly up to 28 days in the stent group (SG). At 28 days, the total vascular area in the BG was reduced to 78% of the control values. In the SG, the total vascular area remained enlarged. According to the phenotypic analysis, the vascular smooth muscle cells (VSMCs) in the neointimal area at 28 days were the contractile type in the BG and the synthetic type in the SG. Proliferating cell nuclear antigen (PCNA) and macrophage-positive cells were not observed in neointima in the BG at 28 days, whereas they were observed around the stent struts in the SG. In addition, numerous inflammatory cells, such as neutrophils and eosinophils, were also present in the SG. CONCLUSIONS: Restenosis after balloon injury consisted of arterial remodeling and neointimal hyperplasia, whereas that after stenting consisted mostly of neointimal hyperplasia. The neointimal area in the SG lasted longer than that in the BG. Continuous inflammation may be an important factor in the restenosis of stenting.     

Thrombospondin secretion by cultured human glomerular mesangial cells.

Thrombospondin is a high-molecular-weight glycoprotein constituent of extracellular matrices of several cells in culture. Immunoreactive thrombospondin is also present within the normal human renal mesangium. To determine whether this thrombospondin could be a synthetic product of the intrinsic glomerular mesangial cells, we examined cultured human glomerular mesangial cells for the ability to synthesize and secrete thrombospondin. Well-characterized human mesangial cells were found to synthesize and secrete thrombospondin, as determined by specific immunostaining at the light- and electron-microscopic levels. Furthermore, metabolically labeled thrombospondin was immunoprecipitated from the conditioned medium of cultured cells. These studies suggest that the thrombospondin present within the normal mesangium is of intrinsic glomerular cell origin. Mesangial thrombospondin may be an important mediator of cellular function, particularly in disease states characterized by intrinsic glomerular cell proliferation.     

Implications of proprotein Convertase 5 (PC5) in the arterial restenotic process in a porcine model.

INTRODUCTION: Convertases (PCs), especially PC5, have been detected in various layers of atherosclerotic and injured arteries. We postulate that PCs could be important enzymes in vascular disease thus studied PC5 expression in a porcine balloon and stent coronary arterial vascular injury model. METHODS: Immunohistochemistry and in situ hybridization of slides of porcine arteries from paraffin blocks were studied 1, 7, 14 and 28 days post injury. RESULTS: Immunohistochemistry studies show expression of PC5 in control artery endothelial cells, weak medial smooth muscle cell (SMC) staining and strong staining in the small nerves of the adventitia. At 7, 14 and 28 days postinjury, there is strong positive PC5 staining of the neointimal cells and the adventitial vasa vasora and myofibroblasts. Colocalization immunohistochemistry confirms the smooth muscle staining properties of the myofibroblast-like cells in both these locations. Single-label immunohistochemistry studies show the same cells to stain strongly positive with TGF-B, PDGF, matrix metalloproteinase-2 (MMP-2) and MMP-9. CONCLUSION: PC5 may be involved in the process of arterial injury via its effect on growth factors (GFs) and mediators. These preliminary observations suggest that the convertases, especially PC5, represent a target for future study in the process of arterial injury.     

Expression of coxsackievirus and adenovirus receptor in neointima of the rat carotid artery.

Our previous study revealed that the coxsackievirus and adenovirus receptor (CAR) is a homophilic cell adhesion molecule and may function as a sensor of cell-cell interactions in the brain and damaged heart. In this study, we investigated if CAR expression is involved in the formation of neointimal hyperplasia using a balloon injury model of rat carotid artery. Cultured vascular smooth muscle cells (SMCs) from rat aorta were also studied. CAR antigen was constitutively detected in the endothelial cells (ECs) but not in SMCs before injury. On Day 5 after balloon injury, CAR was expressed strongly in the first layer of medial SMCs. Neointimal hyperplasia was observed on Day 7, and strong expressions of CAR concomitantly with proliferating cell nuclear antigen (PCNA) were obvious in the neointimal SMCs, while CAR in medial SMCs disappeared. The expression of CAR mRNA reached a peak on Day 7 and declined gradually to the basal levels. When the ECs regenerated on Day 14, CAR antigen was observed in the ECs but disappeared in the neointima. CAR together with PCNA was expressed abundantly in the proliferating SMCs in vitro and diminished in cells grown to a confluent state. The abundant expression of CAR in the neointima may facilitate an adenoviral gene therapy.