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1.
Vascular disease often involves vessel hypertrophy with underlying cellular hypertrophy or hyperplasia. Experimental diabetes stimulates hypertrophy of the rat mesenteric vasculature, and we investigated the hypothesis that this hypertrophy is associated with activation of Na(+)-H(+) exchange (NHE) activity. We measured the NHE activity in isolated, intact blood vessels from control and streptozotocin-induced diabetic adult rats using concurrent myography and fluorescence spectroscopy. The role of inhibiting NHE activity in preventing the development of the mesenteric hypertrophy in streptozotocin-diabetic rats was investigated by administration of cariporide (100 mg/kg body weight per day in 3 doses by gavage) after induction of diabetes and subsequently determining vessel weight and structure. The weight of the mesenteric vasculature was not increased 1 week after streptozotocin treatment but was significantly increased by an average of 56% at 3 weeks. NHE activity in mesenteric arteries showed an enhanced maximal velocity (V:(max)) in diabetic vessels at 1 and 3 weeks (0.246+/-0.006 and 0. 238+/-0.007 versus 0.198+/-0.007 pH U/min) with no change in the apparent K:(m). Moreover, NHE-1 mRNA in mesenteric arterioles at 3 weeks after streptozotocin treatment was increased by >60% (55.8+/-6. 4 versus 91.3+/-12.3 fg). Administration of cariporide significantly reduced mesenteric vascular weight, the wall/lumen ratio, and mesenteric extracellular matrix accumulation in the diabetic animals. Our study shows that diabetes in vivo correlates with elevated NHE activity and mRNA in the mesenteric vasculature and furthermore that inhibition of this system prevents the hypertrophic response. These data suggest that NHE may be a target for therapeutic modulation of vascular changes in diabetes.  相似文献   

2.
目的:探讨大鼠胸主动脉血管成形术后血管外膜激活与血管重塑的相关性。方法:用6F人冠状动脉快速交换球囊损伤大鼠胸主动脉,术后2周和6周取材,行血管形态学定量分析,并行增殖细胞核抗原(PCNA)免疫组织化学染色,观察PCNA在血管外膜上的表达。结果:血管成形术组血管外膜细胞数量、血管外膜细胞增殖指数,外膜面积、厚度均较对照组显著增大(P<0.05),血管外弹力板围绕面积、内弹力板围绕面积和管腔面积较对照组显著减小(P<0.05),血管呈收缩性重塑。结论:血管成形术后,血管外膜被牵拉激活,导致外膜细胞分裂、增殖,以及血管收缩性重塑,参与再狭窄的发生。  相似文献   

3.
Vascular hypertrophy, a feature of experimental and human diabetes, has been implicated in the pathogenesis of the microvascular and macrovascular complications of the disease. In the present study, we sought to examine the role of endogenous endothelin and its relation to vascular growth factors in the mediation of vascular hypertrophy in experimental diabetes and to examine the contribution of mast cells to this process. Vessel morphology, endothelin, growth factor gene expression, and matrix deposition were studied in the mesenteric arteries of control and streptozotocin-induced diabetic Sprague-Dawley rats treated with or without the dual endothelin(A/B) receptor antagonist bosentan (100 mg x kg(-1) x d(-1)) during a 3-week period. Compared with control animals, diabetic animals had significant increases in vessel weight, wall-to-lumen ratio, mast cell infiltration, extracellular matrix deposition, and gene expression of epidermal growth factor (EGF) and transforming growth factor-beta(1). In diabetic, but not control, vessels, not only were EGF mRNA and endothelin present in endothelial cells, but also their expression was observed in adventitial mast cells. Immunoreactive endothelin was present in the media of mesenteric vessels of diabetic, but not control, animals. Bosentan treatment significantly reduced mesenteric weight, wall-to-lumen ratio, mast cell infiltration, matrix deposition, and EGF mRNA but did not prevent the overexpression of transforming growth factor-beta(1) mRNA in diabetic rats. These findings suggest that endogenous endothelin and EGF may play a role in diabetes-induced vascular hypertrophy and that mast cells may be pathogenetically involved in this process.  相似文献   

4.
目的 探讨NADPH氧化酶与Rho/Rho 激酶在外膜介导的血管重塑中的作用。方法在体去除兔颈动脉外膜 ,于术后即刻、1周及 2周取出颈动脉。用图像分析系统测定内膜及中层面积 ;应用多道生理仪测血管反应性 ;原位杂交及RT PCR检测mRNA表达。结果  (1)血管外膜去除后内膜增生 ,2周时内膜增生较 1周时更为明显。对照侧无内膜增生。 (2 )与对照侧比较 ,去外膜侧血管在术后即刻、1周对去甲肾上腺素的收缩反应减弱 (P <0 0 5)。 (3 )与对照侧比较 ,去外膜侧NADPH氧化酶P2 2PhoxmRNA表达在 1周时增高 (P <0 0 5)。 (4)与对照侧比较 ,去外膜侧Rho 激酶mRNA表达在 2周时增高 (P <0 0 5)。结论 外膜去除后血管内膜增生 ,血管舒缩功能改变 ,其发生机制与NADPH氧化酶及Rho 激酶激活有关  相似文献   

5.
目的:观察去血管外膜后兔颈动脉血管内膜增殖及血管反应性改变的情况。方法:在体去除兔颈动脉外膜,于术后0周及1周时取出动脉作组织学检查,血管张力测试,免疫组织化学染色,用RT-PCR法测定返原型辅酶Ⅱ氧化酶P22亚单位(NADPH Oxidase P22Phox)信使核糖核酸(mRNA)。结果:(1)外膜去除方法对血管内皮及中层平滑肌无明显损伤;(2)外膜去除后血管内膜增生,增生成分为血管平滑肌细胞;(3)与完整外膜血管比较,去外膜血管对去甲肾上腺素(NE)的收缩反应在术后即刻及1周均减弱(P<0.05),对乙酰胆碱(Ach)的舒张反应在术后即刻增强(P<0.05);(4)与完整外膜血管比较,去外膜血管NADPH Oxidase P22Phox在1周时表达增高(P<0.05)。结论:外膜去除可致兔颈动脉内膜增生,同时引起血管舒缩反应性发生改变。  相似文献   

6.
本文观察外膜去除后升高血压对血管结构及功能的影响。实验采用在体去除兔颈动脉外膜方法,术后分对照组及高血压组(植入微型药物渗透泵恒量注入去甲肾上腺素),分别于术后1周及2周后取出颈动脉。用图像分析系统测定内膜及中膜面积;应用多道生理仪测血管反应性;RT—PcR检测mRNA表达。结果 1)外膜去除后血管内膜增生,术后2周高血压组去外膜侧内膜面积/中膜面积较对照组增高(P<0.05);2)与完整侧比较,术后1周对照组去外膜侧血管对去甲肾上腺素(NE)的收缩反应减弱(P<0.05);而术后2周对照组与高血压组反应均增强(P<0.05)。与对照组比较,术后1周及2周高血压组去外膜侧血管环反应增强(P<0.05)。3)与对照组比较,术后2周高血压组去外膜侧Rho-A mRNA表达及MCP-1表达较对照组增高(P<0.05)。术后2周对照组及高血压组去膜侧Rho-Ki-nase mRNA表达较完整侧上调(P<0.05);术后1周高血压组完整侧及去外膜侧Rho-Kinase mRNA表达较对照组上调(P<0.05),2周时上调更明显(P<0.01)。术后2周高血压组去外膜侧MCP-1mRNA表达较完整侧上调(P<0.05);术后2周高血压组完整侧及去外膜侧MCP-1mRNA表达明显上调(P<0.01)。结论 高血压可加局外膜去除后的血管内膜增生程度及血管收缩性,其机制涉及Rho-Kinase及MCP-1的激活。  相似文献   

7.
The arterial adventitia has been long considered an essentially supportive tissue; however, more and more data suggest that it plays a major role in the modulation of the vascular tone by complex interactions with structures located within intima and media. The purpose of this review is to summarize these data and to describe the mechanisms involved in adventitia/media and adventitia/intima cross-talk. In response to a plethora of stimuli, the adventitia undergoes remodeling processes, resulting in positive (adaptive) remodeling, negative (constrictive) remodeling, or both. The differentiation of the adventitial fibroblast into myofibroblast (MF), a key player of wound healing and fibrosis development, is a hallmark of negative remodeling; this can lead to vessel stenosis and thus contribute to major cardiovascular diseases. The mechanisms of fibroblast-to-MF differentiation and the role of the MF in adventitial remodeling are highlighted herein.  相似文献   

8.
The role of angiotensin-converting enzyme (ACE) inhibition with ramipril on mesenteric vascular hypertrophy and urinary albumin excretion was explored in a normotensive model of experimental diabetes. Serial measurements of albuminuria were performed in Sprague-Dawley control, diabetic rats, and diabetic rats treated with ramipril. Over 24 weeks, urinary albumin excretion showed a continuous rise in the untreated diabetic rats. Ramipril prevented the increase in albuminuria over the whole study period. After 6 months, animals were perfused with glutaraldehyde and sacrificed for measurement of mesenteric vessel wall/lumen ratio and kidney weight. Diabetes was associated with increased mesenteric wall/lumen ratio and kidney weight. ACE inhibition, despite no effect on glycemic control, attenuated mesenteric vascular hypertrophy but did not decrease kidney weight. In addition to the well-described renoprotective effects of ACE inhibition in diabetes, this class of agents may have a favorable effect on diabetic vascular disease.  相似文献   

9.
Angiotensin (Ang) II is implicated in hypertension, vascular remodeling, and insulin resistance. Peroxisome proliferator-activated receptor (PPAR) gamma activators increase insulin sensitivity and improve Ang II-induced vascular remodeling. We evaluated the effects of the PPAR-gamma activator rosiglitazone on Ang II signaling in aorta and mesenteric arteries. Rats received Ang II by subcutaneous infusion and/or rosiglitazone per os for 7 days. Blood pressure rise in Ang II-infused rats was attenuated by rosiglitazone. Ang II significantly increased Ang II type 1 receptor expression in the mesenteric arteries (P<0.001), whereas that of the aorta was decreased (P<0.05), changes which were reversed by rosiglitazone. Akt activity was increased by Ang II and returned to basal levels under rosiglitazone in both vascular beds. However, Ang II-induced extracellular signal-regulated kinase 1/2 activity increased in aorta but not in mesenteric vessels (P<0.001), where 4E-binding protein 1 activity was significantly increased by Ang II and inhibited by PPAR-gamma activation. In response to Ang II, Src homology (SH) 2-containing inositol phosphatase 2 activity was increased (P<0.05) in both vascular beds. In conclusion, PPAR-gamma activator rosiglitazone attenuated Ang II-induced blood pressure elevation and intracellular signaling on aorta and mesenteric vessels. There was differential inhibition of Ang II type 1 receptor receptors/phosphatidylinositol 3-kinase/Akt and extracellular signal-regulated kinase 1/2 in both vessels. Effects of PPAR-gamma activators on these pathways could contribute to regression of vascular remodeling in models of hypertension and diabetes and, accordingly, in hypertensive diabetic patients.  相似文献   

10.
R M Lee 《Blood vessels》1985,22(3):105-126
Morphometric measurements of three categories of mesenteric vessels (representing elastic, muscular and arteriolar vessels) from prehypertensive spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto rats (WKY) were carried out at the light and electron microscope levels. Structural alterations of the blood vessels were already present in the SHR, even though the blood pressure was not yet elevated as compared with age-matched WKY. No change was found in the elastic vessels (superior mesenteric artery). Among the muscular arteries (i.e. large mesenteric arteries), the increase in vessel wall cross-sectional area was due to the increase in the intima, media and adventitia. Increase in media was due to hyperplasia of the smooth muscle cells. The smooth muscle cells were not hypertrophied. Nerve density was also higher in the large mesenteric arteries of SHR. In the arteriolar vessels (i.e. small mesenteric arteries), wall to lumen ratio, as well as media to lumen ratio, were increased in the SHR. The number of smooth muscle cell layers was also increased. In all these vessel types, the cross-sectional area of the lumen under maximal relaxation was similar between SHR and WKY, except in small mesenteric arteries where the lumen was smaller in the SHR. Our results suggest that structural alteration of the blood vessels at the prehypertensive phase may be one of the contributing factors leading to the development of hypertension in the SHR.  相似文献   

11.
The mast cell has a central role in the pathogenesis of fibrosis a common feature of diabetic microvascular complications. Increased mast cell numbers have been demonstrated in diabetic nephropathy in association with renal fibrosis, and diabetes acutely increases mast cell infiltration in the mesentery. Antimast cell agents such as tranilast may ameliorate the acute vascular changes in diabetes due to stabilisation of mast cells and/or reduction in mast cell numbers. After 3 weeks of streptozotocin diabetes, light microscopy techniques were used to estimate mesenteric vessel fibrosis and mast cell infiltration. Mast cells were identified by toluidine blue staining and tryptase, chymase and TGF-beta immunohistochemistry in three study groups of rats: control, diabetic and plus tranilast. Diabetes was associated with an increase in both mesenteric vessel fibrosis and mast cell numbers. Administration of tranilast to diabetic rats reduced mesenteric vessel fibrosis and this was associated with a reduction in chymase-positive mast cells. These changes were independent of mast cell TGF-beta and were not associated with a reduction in tryptase-positive mast cells. The amelioration of diabetes-induced vessel fibrosis may be due to a reduction in the liberation of angiotensin II by inhibiting mast cell chymase.  相似文献   

12.
Mechanisms underlying endothelial dysfunction in diabetes mellitus   总被引:1,自引:0,他引:1  
Incubation of endothelial cells in vitro with high concentrations of glucose activates protein kinase C (PKC) and increases nitric oxide synthase (NOS III) gene expression as well as superoxide production. The underlying mechanisms remain unknown. To address this issue in an in vivo model, diabetes was induced with streptozotocin in rats. Streptozotocin treatment led to endothelial dysfunction and increased vascular superoxide production, as assessed by lucigenin- and coelenterazine-derived chemiluminescence. The bioavailability of vascular nitric oxide (as measured by electron spin resonance) was reduced in diabetic aortas, although expression of endothelial NOS III (mRNA and protein) was markedly increased. NOS inhibition with N:(G)-nitro-L-arginine increased superoxide levels in control vessels but reduced them in diabetic vessels, identifying NOS as a superoxide source. Similarly, we found an activation of the NADPH oxidase and a 7-fold increase in gp91(phox) mRNA in diabetic vessels. In vitro PKC inhibition with chelerythrine reduced vascular superoxide in diabetic vessels, whereas it had no effect on superoxide levels in normal vessels. In vivo PKC inhibition with N:-benzoyl-staurosporine did not affect glucose levels in diabetic rats but prevented NOS III gene upregulation and NOS-mediated superoxide production, thereby restoring vascular nitric oxide bioavailability and endothelial function. The reduction of superoxide in vitro by chelerythrine and the normalization of NOS III gene expression and reduction of superoxide in vivo by N:-benzoyl-staurosporine point to a decisive role of PKC in mediating these phenomena and suggest a therapeutic potential of PKC inhibitors in the prevention or treatment of vascular complications of diabetes mellitus. The full text of this article is available at http://www.circresaha.org.  相似文献   

13.
OBJECTIVES: This study was performed to test the hypothesis that tenascin-C (TN-C), an extracellular matrix (ECM) protein with counteradhesive chemotactic and vascular growth-promoting effects, is expressed in "arterialized" human saphenous vein grafts (SVGs). BACKGROUND: Tenascin-C is expressed in the vessel wall after vascular injury in the experimental model, where it has been implicated in the formation of neointima. Overexpression of TN-C has also been implicated in the development and progression of pulmonary hypertension. Saphenous vein grafts are exposed to hemodynamic stress when interposed in the arterial circulation and mechanical stress upregulates expression of TN-C, whereas stress-relaxation suppresses its synthesis. We hypothesized that the hemodynamic stress of increased arterial pressure could also induce TN-C expression in SVG. METHODS: We examined the expression of TN-C protein and mRNA in normal vein and "arterialized" human SVG using immunohistochemistry and in situ hybridization, respectively. RESULTS: TN-C protein was not detected in control human saphenous veins; however, it was uniformly and strongly expressed in the adventitia and media of patent human vein grafts, with minimal or no expression in the neointima (n = 27, 100%). In situ hybridization showed that TN-C mRNA was not detected in the neointima, but was strongly upregulated in the adventitia and media, corroborating immunostaining data (n = 10, 100%). Unlike patent SVG, TN-C was not expressed in the adventitia of occluded grafts, except for a low level of expression around the newly formed vessels in neointima (n = 5, 100%). Smooth muscle cell-specific staining demonstrated that the lack of expression of TN-C in occluded vein grafts is not due to the lack of presence of smooth muscle cells in the graft. CONCLUSIONS: These findings suggest that placement of a venous graft in the arterial system leads to expression of TN-C, which may in turn facilitate graft remodeling. Conversely, loss of flow and intravascular pressure, associated with vein graft occlusion, is accompanied by disappearance of TN-C expression.  相似文献   

14.
15.
Clinical pulmonary hypertension is characterized by a sustained elevation in pulmonary arterial pressure. Pulmonary vascular remodeling involves structural changes in the normal architecture of the walls of pulmonary arteries. The process of vascular remodeling can occur as a primary response to injury, or stimulus such as hypoxia, within the resistance vessels of the lung. Alternatively, the changes seen in more proximal vessels may arise secondary to a sustained increase in intravascular pressure. To withstand the chronic increase in intraluminal pressure, the vessel wall becomes thickened and stronger. This "armouring" of the vessel wall with extra-smooth muscle and extracellular matrix leads to a decrease in lumen diameter and reduced capacity for vasodilatation. This maladaptive response results in increased pulmonary vascular resistance and consequently, sustained pulmonary hypertension. The process of pulmonary vascular remodeling involves all layers of the vessel wall and is complicated by the finding that cellular heterogeneity exists within the traditional compartments of the vascular wall: intima, media, and adventitia. In addition, the developmental stage of the organism greatly modifies the response of the pulmonary circulation to injury. This review focuses on the latest advances in our knowledge of these processes as they relate to specific forms of pulmonary hypertension and particularly in the light of recent genetic studies that have identified specific pathways involved in the pathogenesis of severe pulmonary hypertension.  相似文献   

16.
BACKGROUND AND AIMS: Anandamide is an endocannabinoid that evokes hypotension by interaction with peripheral cannabinoid CB1 receptors and with the perivascular transient receptor potential vanilloid type 1 protein (TRPV1). As anandamide has been implicated in the vasodilated state in advanced cirrhosis, the study investigated whether the mesenteric bed from cirrhotic rats has an altered and selective vasodilator response to anandamide. METHODS: We assessed vascular sensitivity to anandamide, mRNA and protein expression of cannabinoid CB1 receptor and TRPV1 receptor, and the topographical distribution of cannabinoid CB1 receptors in resistance mesenteric arteries of cirrhotic and control rats. RESULTS: Mesenteric vessels of cirrhotic animals displayed greater sensitivity to anandamide than control vessels. This vasodilator response was reverted by CB1 or TRPV1 receptor blockade, but not after endothelium denudation or nitric oxide inhibition. Anandamide had no effect on distal femoral arteries. CB1 and TRPV1 receptor protein was higher in cirrhotic than in control vessels. Neither CB1 mRNA nor protein was detected in femoral arteries. Immunochemistry showed that CB1 receptors were mainly in the adventitia and in the endothelial monolayer, with higher expression observed in vessels of cirrhotic rats than in controls. CONCLUSIONS: These results indicate that anandamide is a selective splanchnic vasodilator in cirrhosis which predominantly acts via interaction with two different types of receptors, CB1 and TRPV1 receptors, which are mainly located in perivascular sensory nerve terminals of the mesenteric resistance arteries of these animals.  相似文献   

17.
18.
Aims/hypothesis. Previous studies in our laboratory have shown that the vascular changes in diabetes include hypertrophy of the mesenteric vasculature and that this process can be attenuated by the inhibition of advanced glycation with aminoguanidine. Since aminoguanidine can also act as an inhibitor of nitric oxide synthase, the effect of a novel inhibitor of advanced glycation end-products, formation that does not inhibit nitric oxide synthase, known as 2,3 diaminophenazine (2,3 DAP) was evaluated. Methods. Initially, in vitro assessment of the ability of 2,3 diaminophenazine to inhibit formation of advanced glycation products was performed. Subsequently, in vivo studies evaluating 2,3 diaminophenazine and aminoguanidine were carried out. Animals were followed for 3 weeks after induction of diabetes and randomised to no treatment, aminoguanidine or 2,3 diaminophenazine. Mesenteric vessels were weighed and advanced glycation end-products were measured by radioimmunoassay in vessel and kidney homogenates. In addition, these products were assessed in mesenteric vessels by immunohistochemistry. Results. When compared with control animals, diabetes was associated with an increase in mesenteric vascular weight. Treatment of diabetic rats with aminoguanidine or 2,3 diaminophenazine resulted in attenuation of vascular hypertrophy. Both aminoguanidine and 2,3 diaminophenazine reduced the formation of advanced glycation end-products as measured by radioimmunoassay and as assessed immunohistochemically in these vessels. This reduction was also observed in the kidney. Conclusion/interpretation. These data support the concept that the effects of aminoguanidine in reducing diabetes associated vascular hypertrophy are via inhibition of advanced glycation end-products dependent pathways. [Diabetologia (1999) 42: 472–479] Received: 20 July 1998 and in revised form: 2 November 1998  相似文献   

19.
目的观察血管内液体球囊放射治疗对血管成形术后再狭窄的影响,同时通过观察放射治疗效应探讨放射治疗防止再狭窄发生的可能机制.方法雄性Wistar大鼠72只,体重300~350 g,随机分为两组,胸主动脉经球囊损伤(损伤组),球囊损伤加32P液体球囊血管内照射(照射组,按照射剂量分为20 Gy亚组和28Gy亚组).使用原位杂交方法测定管壁基质金属蛋白酶9(MMP-9)mRNA表达;采用免疫组化的方法测定增殖细胞核抗原(PCNA)表达阳性细胞;用计算机图像分析方法观察血管组织形态学的变化,并对原位杂交和免疫组化的结果进行定量分析.结果照射组与损伤组相比第14天外弹力板围绕面积、管腔面积明显增大,且随照射剂量的增加而增大;第1,3,7天管壁MMP-9 mRNA表达率明显降低,降低程度随照射剂量增加而增大.结论32P液体球囊可防止再狭窄的形成,其机制之一可能是通过抑制管壁MMP-9 mRNA表达,从而抑制血管重塑.  相似文献   

20.
目的探讨全反式维甲酸(ATRA)对兔颈动脉粥样硬化病灶中血管内膜的增生、血管平滑肌细胞(VSMCs)增殖、增殖细胞核抗原(PCNA)及细胞周期素依赖性激酶Cdk2表达规律的影响。方法36只新西兰雄性大白兔随机分为3组:正常饮食组、手术组、ARTA治疗组,每组12只。手术组和治疗组均给予高脂饮食,两周后用空气干燥法制作颈动脉内膜损伤模型,治疗组于术前3d开始给予ATRA灌胃。于术后1、4周处死动物,取病变血管应用HE染色、免疫组化和计算机图像分析法进行形态学、PCNA和Cdk2表达水平的检测。结果①正常动脉壁未见PCNA及Cdk2表达。②手术组在术后第1周时内膜开始增生,第4周增生明显,且出现泡沫细胞、脂质核心形成、管腔狭窄;增生内膜中Cdk2表达水平增高。③治疗组Cdk2的表达明显低于手术组(P<0.05),VSMCs的迁移、增殖、内膜增生和管腔狭窄显著减轻(P<0.05)。④PCNA表达与Cdk2表达呈显著正相关(P<0.01)。结论ARTA可通过抑制Cdk2表达,抑制VSMCs的迁移和增殖,从而抑制兔颈动脉粥样硬化新生内膜过度增生和管腔狭窄。  相似文献   

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