腺苷及腺嘌呤衍生物对冠脉收缩和平滑肌细胞增殖的影响

硝普钠对培养的猪主动脉平滑肌细胞增殖的影响杨小毅，杨永宗，涂玉林，黄红林，曾锋，钟星（衡阳医学院心血管病研究所，衡阳４２１００１）内皮细胞损伤、血管平滑肌细胞增殖在动脉粥样硬化发生发展中起关键作用。硝普钠及其硝基类扩血管药（ｎｉｔｒｏ－ｖａｓｏｄｉｌ...     

冠状动脉内皮功能的研究进展

血管内皮产生各种血管活性物质 ,可以调节平滑肌细胞舒缩活动 ,具有维持血管紧张 ,抑制血小板积聚和平滑肌细胞增生的功能[1] 。如果内皮功能受损 ,将会促使动脉粥样硬化的发生发展[2 ] 。研究发现 ,动脉粥样硬化的各种危险因素都可引起不同程度的内皮功能减低。而冠状动脉是发生动脉粥样硬化最常见和最重要的部位 ,因此检测冠状动脉内皮功能对于早期评价冠状动脉粥样硬化性心脏病具有重要临床价值。1　血管内皮依赖性舒张功能的发生机理1.1　一氧化氮 (ＮＯ) :血管内皮细胞分泌多种物质 ,参与血管紧张性的调节。其中发现ＮＯ是最重要的内皮…     

内皮剥脱后家兔胸主动脉舒张反应的变化

本实验在家兔胸主动脉内皮剥脱模型上，观察血管舒张反应的变化及其与血管平滑肌细胞增殖的关系。结果发现．内皮剥脱后血管对乙酰胆碱的内皮依赖性舒张反应明显降低。术后２周和４周时分别为对照组的２７．７±９．９％和５１．１±１１．４％；实验组和对照组血管对去甲肾上腺素的收缩反应和硝普钠的舒张反应均无显著性差异。内皮剥脱后血管平滑肌细胞显著增殖，内膜增厚。这些结果提示，内皮剥脱后血管的内皮依赖性舒张功能受损，内皮源性舒张因子产生可能减少；血管平滑肌细胞增殖可能与这些变化有关．     

一氧化氮在高脂饲养兔胸主动脉的变化和意义

观察高脂饲养兔胸主动脉血管环对去甲肾上腺素（ＮＥ）的反应性及环磷酸鸟苷（ｃＧＭＰ）含量的变化。结果表明其对ＮＥ的反应性降低，组织ｃＧＭＰ的含量减少。左旋精氨酸（Ｌ－Ａｒｇ）和硝普钠（ＳＮＰ）可恢复此反应性，而一氧化氮合成酶（ＮＯＳ）阻滞剂Ｌ－硝基精氨酸（Ｌ－ＮＮＡ）却加重其降低的反应性。提示高脂饲养兔血管环中的一氧化氮（ＮＯ）减少，Ｌ－Ａｒｇ及ＳＮＰ可以逆转之，暗示Ｌ－Ａｒｇ／ＮＯ通路障碍可能是动脉粥样硬化的又一机理。     

(-)黄皮酰胺对硝普钠诱导的海马神经元凋亡的影响

目的 探讨黄皮叶分离物（-）黄皮酰胺对硝普钠诱导的体外培养大鼠海马神经元凋亡的影响及其可能机制。方法 在硝普钠诱导体外培养的海马神经元凋亡模型的基础上，采用MTT比色分析检测细胞存活率，Western blot及RT-PCR等方法检测捌．2和bax基因表达。结果不同剂量（-）黄皮酰胺预处理6h可提高神经元的存活率，增加bcl-2的表达，降低bax的表达。结论 （-）黄皮酰胺可剂量依赖性地对抗硝普钠的神经毒性作用，其机制可能与增加抗凋亡基因bcl-2的表达，降低促凋亡基因bax表达，增高Bcl-2／Bax的比值有关。     

硝基类扩血管剂与EDRF样物质对冠状动脉微循环作用的比较研究

本研究用离体兔心灌注模型探讨硝基类扩血管剂（ＮＶＤ）及内皮源性舒张因子（ＥＤＲＦ）样物质对冠状动脉微循环的作用机制。将硝酸甘油（ＮＴＧ，３～１０００ｎｍｏｌ／Ｌ）、硝普钠（ＳＮＰ，１～１０００ｎｍｏｌ／Ｌ）、３－ｍｏｒｐｈｏｌｉｎｏｓｙｄｎｏｎｉｍｉｎ（ＳＩＮ－１，３～１００００ｎｍｏｌ／Ｌ）、Ｓ－亚硝基－Ｌ－半胱氨酸（ＣＹＳ－ＮＯ，１～１０００ｐｍｏｌ／Ｌ）、双亚硝基－亚铁复合物（ＤＮＩＣ，３～３０００ｎｍｏｌ／Ｌ）和一氧化氮（ＮＯ，０．１～３０ｎｍｏｌ／Ｌ）依次注入主动脉内，呈现一系列瞬时的剂量依赖性的冠状动脉灌注压（ＣＰＰ）降低，ＥＤＲＦ样物质的有效半量或有效半量比值明显低于ＮＶＤ，而其曲线斜率Ａ值高于ＮＶＤ。另在持续输入谷胱甘肽－Ｓ－转换酶（ＧＳＴ）抑制剂溴酚酞磺酸钠（ＳＢＰ，３０ｕｍｏｌ／Ｌ）前后分别给予ＮＴＧ（３，３０，３００ｎｍｏｌ／Ｌ），后者所引起的ＣＰＰ下降百分数及扩张持续时间均明显被抑制。上述结果提示：（１）冠状动脉微血管内缺乏ＮＶＤ生物转化所需的巯基供体，这是冠状动脉阻力血管对ＥＤＲＦ类物质的反应性显著高于ＮＶＤ的原因；（２）ＧＳＴ参与ＮＴＧ的生物代谢。     

阿司匹林改善动脉粥样硬化血管内皮机能障碍

阿司匹林治疗动脉粥样硬化，主要是通过它的抗血小板活性作用，而其对血管内皮机能的影响尚不清楚。假设一种依赖性环氧合酶收缩因子，可促使动脉粥样硬化者血管内皮机能障碍，而阿司匹林的作用与其相反。患者１９人，其中１４人被确诊患冠状动脉粥样硬化，５人有一种或多种导致动脉粥样硬化的危险因素。静注阿司匹林前后，用乙酰胆碱和Ｐ物质检测股骨血管内皮机能，用硝普钠检测其非依赖性内皮机能，药物注射后，用多普勒测定血流速度。结果：动脉粥样硬化患者因乙酰胆碱而引起的血管舒张比带有动脉粥样硬化危险因素者弱，而阿司匹林可明显…     

冠状动脉内注射硝普钠与硝酸甘油在急性心肌梗死急诊手术中的临床对照研究

目的:观察急性心肌梗死患者急诊冠状动脉介入治疗(PCI)中冠状动脉内给予硝普钠或冠状动脉内给予硝酸甘油的临床疗效。方法:将急性ST段抬高型心肌梗死的患者152例随机分为硝普钠组(78例)和硝酸甘油组(74例),常规治疗的基础上,冠状动脉内分别注射硝普钠或硝酸甘油,PCI后行冠状动脉造影检查,观察其TIMI血流分级及ST段50%回落率,并观察患者住院期间及术后6个月内的心血管事件发生率,作为评价指标。结果:2组患者临床基本指标比较无统计学差异(P0.05);慢血流与无复流的发生率硝酸甘油组高于硝普钠组(P0.05);PCI后6个月随访示硝普钠组与硝酸甘油组患者左室射血分数、左室舒张末直径以及心脏不良事件发生率比较,均差异有统计学意义(P0.05)。结论:PCI中冠状动脉内给予硝普钠较硝酸甘油可明显改善冠状动脉慢血流或无复流,对于急性心肌梗死患者可改善术后即刻血流,减少远期临床事件。     

胰岛素对血管平滑肌细胞增殖及原癌基因c-fos和c-myc表达的影响

用３Ｈ－胸腺嘧啶核苷掺入实验及细胞计数法等观察了胰岛素对体外培养的人血管平滑肌细胞ＤＮＡ合成、细胞增殖及原癌基因：ｃ－ｆｏｓ和ｃ－ｍｙｃ表达的影响。结果发现，在培养基中加入不同浓度的胰岛素后，血管平滑肌细胞增殖，细胞ＤＮＡ合成增加，原癌基因ｃ－ｆｏｓ、ｃ－ｍｙｃ表达增加，上述三者均具有胰岛素剂量依赖性，呈现量－效关系．实验结果表明，高胰岛素血症可能通过促进平滑肌细胞增殖和原癌基因ｃ－ｆｏｓ和ｃ－ｍｙｃ表达和来加速动脉粥样硬化的发生与发展的。     

性激素对心血管的直接作用

雌激素对心血管的直接作用是其防止心血管疾病最重要的作用，其机制可能包括钙离子拮抗作用，促进内皮细胞ＮＯ合成作用，抑制血管平滑肌细胞增殖及动脉粥样硬化的形成和艇等。目前尚无雄激素增高心血管疾病发病率的证据，相反却有雄激素改善冠状脉紧张度的报道。     

Nitrite-generated nitric oxide to protect against intimal hyperplasia formation

Vascular disease is a leading cause of morbidity and mortality worldwide. Current vascular therapeutic interventions directed at diseased vessels are restricted in long-term efficacy by the development of intimal hyperplasia and the reformation of flow-limiting disease. The vascular injury and inflammation that ensues from the intervention, especially in the setting of an existing atherosclerotic vascular disease, results in further endothelial dysfunction and subsequent smooth muscle cell proliferation and migration. Although the etiology of intimal hyperplasia is multifactorial, impaired nitric oxide (NO) signaling has been implicated. The vasoprotective properties of NO have been intensely studied, and many investigations have focused on harnessing this biological system for therapeutic benefit. Continued studies investigate the role of impaired NO signaling via the classical arginine/NO synthase (NOS)/NO pathway in the setting of intimal hyperplasia. Furthermore, the possible protective effects of nitrate and nitrite-generated NO via non-NOS-mediated pathways to limit vascular injury have been recently appreciated and will likely prove to be an important vasoregulatory and vasoprotective signaling pathway.     

Nitric oxide inhibits proliferation of human endothelial cells via a mechanism independent of cGMP.

Endothelial cell-derived nitric oxide (NO) has been suggested to inhibit smooth muscle cell proliferation, resulting in the reduction of intimal hyperplasia during atherogenesis. The present study investigates the role of NO from exogenous and endogenous sources on the proliferation of human umbilical vein endothelial cells (HUVEC) and human coronary artery endothelial cells (CAEC). Three different NO-generating compounds [sodium nitroprusside (SNP), S-nitroso-glutathione (GSNO) and S-nitroso-acetylpenicillamine (SNAP)] were found to inhibit endothelial cell proliferation measured with three independent methods (cell counting, [3H]thymidine incorporation, DNA histograms) with significant inhibition occurring at concentrations > or = 100 microM. Growth-inhibiting effects were observed after long-term treatment (18-96 h) as well as after short stimulation with NO donors (10 min with a subsequent NO donor-free culture period of 18 h) and were comparable in culture medium (20% serum, growth factor supplementation) and serum-deficient medium (1% serum). The NO donor effects were mediated by the release of NO as they were prevented by NO scavenging. Superoxide dismutase (SOD) was found not to interfere with these effects suggesting that peroxynitrite formation was unlikely to be involved. 1H-[l,2,4]Oxadiazolo[4,3,-alpha]quinoxalin-1-one (ODQ), a specific inhibitor of the soluble guanylate cyclase, was observed not to alter the antiproliferative effects of NO donors although it completely prevented NO-mediated increase of cyclic guanosine 3',5'-monophosphate (cGMP), suggesting that the NO-induced growth inhibition was not mediated by cGMP. Furthermore, inhibition of endogenous NO production by N-nitro-L-arginine methylester (L-NAME) did not affect endothelial cell growth regardless of using serum plus growth factor supplement, growth factor supplement alone, or thrombin to stimulate proliferation. We suggest that constitutively synthesized NO may not regulate endothelial cell proliferation whereas the growth-inhibiting NO effects may occur when an inducible NO synthase associated with a persistently high NO production is expressed in the atherosclerotic vessel wall.     

Inducible nitric oxide synthase and atherosclerosis

Nitric oxide (NO) synthase induction in vascular smooth muscle cells may play a role in local vascular injury associated with atherosclerosis or postangioplasty restenosis by inhibiting smooth muscle cell proliferation and contraction, as well as by preventing leukocyte and platelet adhesion. The expression of inducible NO synthase is increased in balloon-injured arteries of experimental animals or in human atherosclerotic lesions. Replacement therapy with NO donors or NO synthase gene transfer may improve the clinical course of atherosclerosis or restenosis.     

A proatherogenic role for cGMP-dependent protein kinase in vascular smooth muscle cells

Nitric oxide (NO) exerts both antiatherogenic and proatherogenic effects, but the cellular and molecular mechanisms that contribute to modulation of atherosclerosis by NO are not understood completely. The cGMP-dependent protein kinase I (cGKI) is a potential mediator of NO signaling in vascular smooth muscle cells (SMCs). Postnatal ablation of cGKI selectively in the SMCs of mice reduced atherosclerotic lesion area, demonstrating that smooth muscle cGKI promotes atherogenesis. Cell-fate mapping indicated that cGKI is involved in the development of SMC-derived plaque cells. Activation of endogenous cGKI in primary aortic SMCs resulted in cells with increased levels of proliferation; increased levels of vascular cell adhesion molecule-1, peroxisome proliferator-activated receptor gamma, and phosphatidylinositol 3-kinase/Akt signaling; and decreased plasminogen activator inhibitor 1 mRNA, which all are potentially proatherogenic properties. Taken together, these results highlight the pathophysiologic significance of vascular SMCs in atherogenesis and identify a key role for cGKI in the development of atherogenic SMCs in vitro and in vivo. We suggest that activation of smooth muscle cGKI contributes to the proatherogenic effect of NO and that inhibition of cGKI might be a therapeutic option for treating atherosclerosis in humans.     

Functional modulation of smooth muscle cells by the inflammatory mediator CAP37

CAP37, a neutrophil-derived protein, originally identified for its antimicrobial activity is now known to have strong immunoregulatory effects on host cells. Recently, we described its expression and localization within the vascular endothelium associated with atherosclerotic plaques. Since CAP37 is a potent activator of endothelial cells and monocytes, two of the key cellular components of the atherosclerotic plaque, this study was undertaken to determine whether CAP37 had functional effects on smooth muscle cells another important cellular participant in atherosclerosis. Sections from atherosclerotic lesions were stained for the presence of CAP37 and smooth muscle cell alpha actin. The effect of CAP37 on aorta smooth muscle cell migration and proliferation was investigated and the upregulation of adhesion molecules was determined. Immunocytochemistry indicated that CAP37 was present in a subset of smooth muscle cells within atherosclerotic lesions, but was absent in normal vessels. Flow cytometry using double labeling for the proliferation marker Ki-67 and CAP37 demonstrates that CAP37 is mainly expressed in proliferating smooth muscle cells. We show that CAP37 supports migration and proliferation of smooth muscle cells in vitro. Furthermore, CAP37-treated smooth muscle cells expressed higher levels of the cell adhesion molecule ICAM-1 when compared with untreated cells. We suggest that due to its localization to atherosclerotic plaques and its ability to modulate smooth muscle cells, CAP37 may play a role in the progression of this disease.     

Cell proliferation in human coronary arteries.

Despite the lack of direct evidence for cell multiplication, proliferation of smooth muscle cells in human atherosclerotic lesions has been assumed to play a central role in ontogeny of the plaque. We used antibodies to cell cycle-related proteins on tissue sections of human arteries and coronary atherosclerotic plaques. Specific cell types were identified by immunochemical reagents for smooth muscle, monocyte-macrophages, and other blood cells. Low rates of smooth muscle cell proliferation were observed. Macrophages were also observed with rates of proliferation comparable to that of the smooth muscle. Additional replicating cells could not be defined as belonging to specific cell types with the reagents used in this study. These findings imply that smooth muscle replication in advanced plaques is indolent and raise the possibility of a role for proliferating leukocytes.     

不要低估血管平滑肌细胞在动脉粥样硬化斑块形成中的作用

血管内皮细胞、平滑肌细胞(SMC)和巨噬细胞共同参与动脉粥样硬化(As)斑块形成。近年研究表明,SMC来源的细胞占As斑块中细胞总数的70%以上。As斑块中的SMC通过自分泌细胞因子促进自身的增殖、迁移和炎症反应,通过旁分泌激活单核/巨噬细胞并将其募集到As损伤部位,同时通过其细胞膜表面表达的脂蛋白受体摄取脂质形成泡沫细胞。SMC在As斑块形成中扮演十分重要的角色,应进一步深化对SMC在As发生发展中的作用及作用机制的研究。     

AngⅡ,NO对VEC,VSMC增殖及凋亡的影响

目的 了解血管活性物质AngⅡ、NO对VEC、VSMC增殖及凋亡的影响。方法 在培养的VEC、VSMC细胞中加入NO、AngⅡ等物质,观察细胞生长及凋亡情况。结果 NO诱导VSMC凋亡而AngⅡ抑制VSMC凋亡,NO拮抗AngⅡ对VEC凋亡的诱导作用。结论 血管活性物质NO、AngⅡ调节VEC及VSMC增殖与凋亡的能力与调节血管张力的相互抵消作用一致,这些血管活性物质的表达失去平衡可使调节血管张力、细胞增殖及细胞死亡的内环境稳定发生紊乱。