一氧化氮与血管老化

NO是体内的一种信号分子,具有广泛的生理功能。它作为内皮源性舒张因子,对于调节血管的力学特性、血流状态有重要作用,并与血管老化和疾病发生有密切的关系。 一、NO的产生 在生理条件下,内皮细胞能产生和释放NO,体内NO生物合成的反应式为:L-精氨酸+O_2(一氧化氮合成酶)NO+瓜氨酸。     

神经型一氧化氮合酶羧基末端结合配体CAPON的研究进展

正内皮衍生小分子气体一氧化氮(nitric oxide,NO)因阐明了NO在心血管系统中是具有重要调节作用。随后的研究揭示了NO参与多种病理生理过程,包括血管舒张、神经传递、巨噬细胞街道的细胞毒性、胃肠道平滑肌舒张及支气管扩张~[1]。在生物体内,NO的生成过程需要关键酶一氧化氮合酶(nitric oxide synthase,NOS)的参与,将L-精氨酸(L-arginine,L-Arg)和分子氧作为底物,由还原型烟酰胺腺嘌呤二核苷酸     

内源性一氧化氮在急性高原病中的研究进展

1一氧化氮(nitric oxide,NO)与内源性一氧化氮(endogenous NO,eNO) NO是具有调节血管张力、血流等众多生物学作用的脂溶性气体信号分子,eNO是由L-精氨酸(L-arginine,L-Arg)经过体内一氧化氮合酶[nitric oxide synthase,NOS;主要有神经源型(neuronal NOS,nNOS)、诱导型(inducible NOS,iNOS)和内皮源型(endothelial NOS,eNOS)3种]催化合成的,广泛存在于全身组织[1].NO通过一些生物分子和细胞间相互作用参与机体的保护、调节及逆转等生理过程[2].近年来的研究发现NO在调节血管张力、抑制炎症以及抗动脉粥样硬化中发挥关键作用[1-2].     

左旋精氨酸对被动吸烟孕鼠及胎仔发育的作用及其与NO、NOS的关系

目的了解左旋精氨酸对被动吸烟所致大鼠宫内发育迟缓及胎仔生长发育的作用,通过其与NO、NOS的关系探讨其作用机理.方法利用被动吸烟法建立大鼠IUGR模型,孕鼠随机分为5组:对照组、模型组、低剂量左旋精氨酸组、中剂量左旋精氨酸组、高剂量左旋精氨酸组.孕21天剖宫取胎,观察胎盘重、仔重、仔脑重、仔肝重;检测孕鼠血清及胎盘组织中NO含量及iNOS、cNOS活性.结果与对照组比较,模型组孕鼠胎盘重及仔重、仔脑重、仔肝重均明显降低(P<0.01),孕鼠血清及胎盘组织NO含量下降,iNOS活性升高,cNOS活性下降(P<0.01).低剂量及中剂量左旋精氨酸组与模型组比较各指标均有改善,但高剂量左旋精氨酸组与模型组比较无明显差异.结论孕中期应用一定剂量左旋精氨酸可有效防治被动吸烟孕鼠IUGR的发生并对胎仔发育有显著促进与保护作用,其作用与NO/NOS系统有关系.     

睾丸一氧化氮合酶与雄性生殖

一氧化氮合酶 (nitricoxidesynthase ,NOS)在NADPH(还原型辅酶Ⅱ )存在下催化L -精氨酸分解生成一氧化氮(nitricoxide,NO)。NOS有以下几种形式 :神经型NOS(nNOS) ,诱导型NOS(iNOS) ,内皮型NOS(eNOS)。NO是目前研究最多的体内信息分子和效应分子 ,广泛存在于人体的心血管系统、神经系统、消化系统、免疫系统、生殖系统等。NOS和NO对生殖活动的作用已被广泛研究 ,如对睾丸微循环的调解 ,参与睾酮分泌 ,调解精子活动等。本文对睾丸NOS/NO与雄性哺乳动物生殖关系的研究进展作一概述。     

L-精氨酸对妊高征的治疗作用及其机制的探讨

目的 :探讨硫酸镁和L 精氨酸联合治疗妊高症的有效性。方法 :设立对照组和妊高征组并利用硫酸镁、L 精氨酸及联合用药 (硫酸镁 +L 精氨酸 )治疗 ,观察其动态血压和 2 4h尿蛋白定量及一氧化氮 (NO)、一氧化氮合酶 (NOS)、内皮素 (ET)、血管紧张素Ⅱ (ANGⅡ )、血栓烷 (TXA2 )、前列环素 (PGI2 )等指标的变化。结果 :与对照组比较 ,妊高征组NO、PGI2 含量及NOS活性明显降低 (P <0 .0 1) ,ET、ANGⅡ及TXA2 明显升高 (P <0 .0 1)。中度与重度妊高征组治疗前后NO、NOS、TXB2 、AngⅡ水平比较 ,有显著性差异 (P <0 .0 5 ) ,而ET水平在中度与重度妊高征组相比较P <0 .0 1。联合用药组临床疗效明显优于硫酸镁组和L 精氨酸组 (P <0 .0 1)。结论 :NO水平、NOS活性降低及血管调节因子失衡 ,可能为妊高征的发病因素 ;L 精氨酸联合硫酸镁对妊高征有明显的治疗作用 ,为妊高征的治疗提供了新的方法     

L-精氨酸和一氧化氮抑制剂对大鼠血管钙化的影响

观察给予一氧化氮合酶(NOS)的抑制剂左旋硝基精氨酸(L-NNA)或底物L-精氨酸(L-Arg)对血管钙化的影响。利用维生素D3和尼古丁制备大鼠血管钙化模型，测定大鼠尾动脉压，血管钙含量、碱性磷酸酶活性及^45Ca沉积；并检测血管组织的L-Arg转运，NOS活性及NO2^-和cGMP含量。发现钙化大鼠血压略升高；动脉钙含量、ALP活性及^45Ca沉积明显增加，von Kossa染色可以看到明显的钙化颗粒；钙化血管组织NOS活性升高；NO和cGMP含量均减少。给予L-NNA或L-Arg后，与单纯钙化组相比，L-NNA干预组的L-Arg转运、NOS活性及NO和cGMP的含量均降低；而L-Arg干预组上述指标的变化正相反。同时，L-NNA干预组的钙化程度比钙化组加重，而L-Arg干预组的钙化程度比钙化组减轻；提示血管钙化时NO—NOS—cGMP途径发生紊乱，干预NO—NOS—cGMP途径可以影响钙化的进程。     

阿司匹林对炎症条件下人血管内皮细胞一氧化氮的产生及诱导型一氧化氮合酶mRNA表达的影响

目的:探讨炎症时阿司匹林(AS)对内皮细胞一氧化氮(NO)的产生及诱导型一氧化氮合酶(iNOS)基因表达的抑制作用。方法:Griess法测上清液NO^-₂/NO^-₃水平、黄递酶法测NOS活性、常规生化法测乳酸脱氢酶(LDH)、丙二醛(MDA)浓度,染料排除法测细胞活力,RT-PCR技术分析iNOSmRNA水平。结果:白介素(IL)-1β、肿瘤坏死因子(TNF)-α、γ-干扰素(INF)联用脂多糖(LPS)诱导后上清液中NO^-₂/NO^-₃由(4.27±0.75)μmol/L增加到(9.35±1.25)μmol/L,对内皮细胞造成明显的损伤。但3mmol/LAS组NO生成及NOS活性明显降低,LDH释放率及MDA浓度下降,细胞存活率上升,与NO诱导组相比差异显著。并随AS剂量的增加对NO的抑制及对细胞的保护作用更加明显,但AS对生理水平的NO没有抑制作用。同时发现10mmol/L浓度以下AS对iNOSmRNA表达水平没有影响;但10-20mmol/L的AS则可在转录水平上抑制iNOSmRNA的表达。并观察到水杨酸钠及消炎痛不具有抑制NO产生的作用。结论:AS具有明显抑制IL-1β、TNF-α、γ-INF及LPS诱导NO生成的作用,从而保护血管内皮细胞避免炎症时高浓度NO的损伤。     

白藜芦醇通过调节iNOS抑制C57BL/6J小鼠动脉粥样硬化的机制探讨

目的:探讨白藜芦醇(resveratrol,RES)对卵巢切除小鼠血脂四项总胆固醇(CHOL)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)以及血清一氧化氮(nitric oxide,NO)含量、胸主动脉的过氧亚硝基阴离子(peroxynitrite anion,ONOO-)及诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)蛋白表达水平的影响。方法:雌性C57小鼠经卵巢切除建立去势模型后,分为假手术组、单纯去势组、假手术高脂组、模型高脂组和RES组。单纯去势组和假手术组给予普通饲料,其余给予高脂饲料。14周后,收集血清检测各组血清的CHOL、TG、LDL-C和HDL-C水平,硝酸还原酶法测血浆NO水平,油红O染色观察动脉粥样硬化(atherosclerosis,AS)情况,DAB染色测定血管ONOO-及iNOS水平,免疫印迹测定血管组织的iNOS表达。结果:模型高脂组血清CHOL、TG、LDL-C和NO较正常对照组升高(P0.05);与模型高脂组相比,RES组可降低小鼠血清的TC、TG、LDL-C和NO(P0.05);14周后,AS模型成功建立,模型高脂组有明显的AS病理改变,单纯去势组无明显AS斑块,RES组AS病变明显减轻;高脂喂养14周后,模型高脂组血管组织的iNOS及ONOO–表达也较正常对照组明显提高(P0.05);与模型高脂组相比,RES组可降低小鼠胸主动脉的iNOS表达(P0.05),与此同时,血管ONOO-含量较模型高脂组降低。结论:RES可以抑制iNOS表达,减少NO生成,防治动脉粥样硬化。     

血红素氧合酶-1/一氧化碳与一氧化氮合酶/一氧化氮系统抑制球囊损伤后再狭窄的作用及其相关性研究

目的:探讨血红素氧合酶-1(HO-1) /一氧化碳(CO)系统与一氧化氮合酶(NOS) /一氧化氮(NO)系统抑制兔颈动脉球囊损伤后再狭窄的作用和相互关系。方法:家兔随机分为:对照组、胆固醇组、血红素组、卟啉锌组、精氨酸组、亚硝基组和假手术组(每组10只)。对照组予普通饮食,其余6组喂饲含1.5%胆固醇饲料,血红素组和卟啉锌组同时分别给予氯化血红素或锌原卟啉-9腹腔内注射,精氨酸组和亚硝基组同时饮水,给予L-精氨酸或亚硝基-L-精氨酸甲酯,2周后实验组行颈总动脉球囊损伤术,术后继续原方式喂养8周。结果:6组高胆固醇喂养家兔的血脂(TC、TG、LDL、ox-LDL)水平显著升高(P均0.01)。与对照组比较,胆固醇组颈动脉NO生成量、NOS活性显著降低,而CO生成量、HO-1活性、内膜面积显著增加(P均0.01)。与胆固醇组比较,血红素组HO-1活性、CO生成量显著增加,内皮素-1(ET-1)水平显著降低,内膜面积和内膜/中膜面积比减小(P均0.01);卟啉锌组HO-1活性、CO生成量明显降低,ET-1水平、内膜面积和内膜/中膜面积比显著增加(P均0.01);精氨酸组cNOS活性、NO生成量显著增加,ET-1水平,内膜面积和内膜/中膜面积比明显降低(P均0.01);亚硝基组cNOS活性、NO生成量明显降低,ET-1水平、内膜面积和内膜/中膜面积比显著增加(P均0.01)。结论:HO-1 / CO与NOS/NO系统均有抑制再狭窄的作用,两系统作用互补且相互代偿,HO-1 /CO系统通过调节和代偿NOS、NO以及下调ET-1而抑制血管损伤后再狭窄。     

Nitric oxide and HSP70 proteins during normal pregnancy,gestosis, and preclinical gestosis

We measured the content of NO metabolites in blood plasma and urine and concentration of HSP70 proteins in the plasma and leukocytes from 126 women with normal pregnancy, gestosis, and preclinical gestosis. In women with gestosis accompanied by NO deficiency the concentration of HSP70 proteins in the plasma increased more significantly than in leukocytes. These changes are an important marker of endothelial dysfunction and reflect the severity of cell damage during this disorder. The decrease in excretion of NO in the urine and increase in HSP70 protein content in leukocytes and plasma characterize endothelial dysfunction in women with preclinical gestosis.     

Plasma detection of NO by a catheter

Nitric oxide (NO) released by endothelial cells in response to hemodynamic shear stress is a key controller molecule of the vascular functions and antiatherogenic mechanisms. Endothelial dysfunction is associated with increased cardiovascular events. Therefore, several indirect techniques have been employed to evaluate endothelial function or NO bioavailability. However, a growing body of evidences suggests limitations of the indirect methods for evaluation of NO bioavailability. In years, it has been considered that NO is immediately oxidized or inactivated in blood stream. However, recent studies suggest that NO remain active in blood stream, causing remote biological response. Therefore, measuring plasma NO concentration directly in the circulation will contribute to clarify the kinetics and physiological roles of NO and to evaluate endothelial function. In this article, the measurement of plasma NO concentration using a newly developed catheter-type NO sensor will be described.     

Adaptation to hypoxia prevents disturbances in cerebral blood flow during neurodegenerative process

The rats with neurodegenerative brain disorder induced by administration of a toxic fragment of β-amyloid demonstrate weakened endothelium-dependent dilation of cerebral vessels, which attested to impaired production of endothelial NO. At the same time, toxic β-amyloid fragment induced the formation of NO depots in the walls of cerebral vessels, which indirectly attests to NO overproduction in the brain tissue. Preadaptation to hypoxia prevented endothelial dysfunction and improved the efficiency of NO storage. Our results suggest that adaptation to hypoxia protects the brain from various changes in NO production during neurodegenerative damage. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 142, No. 8, pp. 132–135, August, 2006     

Assessment of endothelial function and blood metabolite status following acute ingestion of a fructose-containing beverage

Aim: Fructose intake has increased concurrent with sugar intake and this increase has been implicated in contributing to the development of metabolic syndrome risk factors. Recent evidence suggests a role for uric acid (UA) as a potential mediator via suppression of nitric oxide (NO) bioavailability. The aim of this study was to explore this hypothesis by measuring changes in UA concentration and systemic NO bioavailability as well as endothelial function in response to acute ingestion of a glucose-fructose beverage. Methods: Ten young (26.80 ± 4.80 years), non-obese (body mass index: 25.1 ± 2.55 kg m⁻²; percent body fat: 13.5 ± 6.9%) male subjects ingested either a glucose (100 g dextrose in 300 mL) or isocaloric glucose-fructose (glucose : fructose; 45 : 55 g in 300 mL) beverage. Blood was sampled pre- and every 15-min post-ingestion per 90 min and assayed for glucose, lactate, fructose, total nitrate/nitrate, UA and blood lipids. Forearm blood flow and pulse-wave velocity were recorded prior to and at 30 and 45 min time intervals post-ingestion, respectively, while heart rate, systolic and diastolic blood pressure were recorded every 15 min. Results: The glucose-fructose ingestion was associated with a significant (P < 0.05) increase in plasma lactate concentration and altered free fatty acid levels when compared with glucose-only ingestion. However, UA was not significantly different (P = 0.08) between conditions (AUC: −1018 ± 1675 vs. 2171 ± 1270 μmol L⁻¹ per 90 min for glucose and glucose-fructose conditions respectively). Consequently, no significant (P < 0.05) difference in endothelial function or systemic NO bioavailability was observed. Conclusion: Acute consumption of a fructose-containing beverage was not associated with significantly altered UA concentration, endothelial function or systemic NO bioavailability.     

低糖诱导人脐静脉内皮细胞一氧化氮与活性氧变化的研究

目的观察低浓度葡萄糖对人脐静脉内皮细胞一氧化氮（NO）与活性氧（ROS）变化的影响。方法以体外培养人脐静脉内皮细胞株HUVEC-12为研究对象,将实验分为正常对照组（5.5mmol/L葡萄糖）、低糖组（2.8mmol/L葡萄糖）、无糖组（0mmol/L葡萄糖）。分别用2.8、0mmol/L葡萄糖干预HUVEC-12细胞,经过1、2、4、12h后,硝酸还原酶法测定NO产量,化学比色法测定一氧化氮合成酶（NOS）活性,Dihydroethidium荧光探针法测定细胞内ROS水平。结果与正常对照组相比,低糖组与无糖组NO水平降低（P〈0.01）,NOS活性下降（P〈0.01）,细胞内ROS水平升高（P〈0.01）,均呈剂量依赖关系。同一浓度组内随着时间的延长,内皮细胞NO水平、NOS活性进一步降低（P〈0.01）,ROS水平进一步升高（P〈0.05）,各指标都具有浓度和时间依赖性。结论低糖可导致内皮细胞功能障碍,NO水平降低,NOS活性下降,其机制可能与低糖导致内皮细胞氧化应激损伤有关。     

Apoptosis of leukocytes as a marker of neutrophil-endotheliocyte interaction in coronary heart disease

We studied the mechanism of interaction of peripheral blood neutrophils with endothelial cells (expression of cell adhesion molecules and production of NO) and the role of neutrophil apoptosis in the development of endothelial dysfunction. The effects of mitochondrial dysfunction of neutrophils on the development of apoptosis of these cells after their interaction with endothelial cells were analyzed. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 7, pp. 42–44, July, 2007     

Arginase Inhibition Restores Peroxynitrite-Induced Endothelial Dysfunction via L-Arginine-Dependent Endothelial Nitric Oxide Synthase Phosphorylation

PurposePeroxynitrite plays a critical role in vascular pathophysiology by increasing arginase activity and decreasing endothelial nitric oxide synthase (eNOS) activity. Therefore, the aims of this study were to investigate whether arginase inhibition and L-arginine supplement could restore peroxynitrite-induced endothelial dysfunction and determine the involved mechanism.ResultsSIN-1 treatment increased arginase activity in a time- and dose-dependent manner and reciprocally decreased nitrite/nitrate production that was prevented by peroxynitrite scavenger in HUVECs. Furthermore, SIN-1 induced an increase in the expression level of arginase I and II, though not in eNOS protein. The decreased eNOS phosphorylation at Ser1177 and the increased at Thr495 by SIN-1 were restored with arginase inhibitor and L-arginine. The changed eNOS phosphorylation was consistent in the stability of eNOS dimers. SIN-1 decreased NO production and increased ROS generation in the aortic endothelium, all of which was reversed by arginase inhibitor or L-arginine. N^G-Nitro-L-arginine methyl ester (L-NAME) prevented SIN-1-induced ROS generation. In the vascular tension assay, SIN-1 enhanced vasoconstrictor responses to U46619 and attenuated vasorelaxant responses to acetylcholine that were reversed by arginase inhibition.ConclusionThese findings may explain the beneficial effect of arginase inhibition and L-arginine supplement on endothelial dysfunction under redox imbalance-dependent pathophysiological conditions.     

Nitric oxide synthesis is increased in the endometrial tissue of women with endometriosis

BACKGROUND: Previous studies have shown that peritoneal macrophages from women with endometriosis produce excess nitric oxide (NO). This study was designed to quantify the amount of NO and determine the expression of endothelial (eNOS) and inducible NO synthases (iNOS) in women with and without endometriosis. METHODS: An enzyme-linked immunosorbent assay (ELISA) was performed on endometrial tissues obtained from controls (myoma, n = 30) and on eutopic/ectopic endometrial tissues from endometriosis patients (n = 34) to evaluate eNOS and iNOS protein concentrations in these endometrial tissues. A rapid-response chemiluminescence analyser was used to measure NO directly in fresh endometrial tissues. RESULTS: Mean (+/- SEM) levels of NO were significantly increased in the endometrial tissues of women with endometriosis (13.2 +/- 7.8 versus 19.8 +/- 12.6 nmol/g tissue; P = 0.016). Apparently higher levels of NO were found in ectopic compared with eutopic endometrium (P = 0.057). Endometrial tissues of women with endometriosis appeared to contain more iNOS than those of controls (3.6 +/- 2.2 versus 8.6 +/- 12.2 pg/ microg protein; P = 0.06), but no significant difference was found in eNOS levels. CONCLUSIONS: Greater amounts of NO and NOS are present in the endometrial tissues of women with endometriosis, implying a possible role for NO in the pathogenesis of endometriosis.     

1-磷酸鞘氨醇在高糖诱导血管内皮细胞功能损伤中的作用

 目的: 探讨1-磷酸鞘氨醇(S1P)在高糖诱导血管内皮细胞功能损伤中的作用及其机制。方法: 在高糖培养的人主动脉内皮细胞模型中,分别或同时给予S1P、鞘氨醇激酶1抑制剂和Akt抑制剂处理后,观察一氧化氮(NO)、粒细胞-内皮细胞黏附率、细胞间黏附分子1(ICAM-1)蛋白表达、内皮细胞迁移以及Akt/内皮型一氧化氮合酶(eNOS)信号途径的改变。结果: S1P明显降低高糖诱导的内皮细胞培养上清液中NO含量,促进粒细胞与内皮细胞黏附,显著增加内皮细胞ICAM-1蛋白表达,抑制内皮细胞迁移和Akt/eNOS信号通路激活。鞘氨醇激酶1抑制剂减少S1P生成后上述内皮细胞功能指标得以明显改善,Akt/eNOS信号通路恢复激活。结论: S1P促进高糖培养的内皮细胞功能障碍的形成,可能与其抑制Akt/eNOS信号通路激活有关。抑制S1P生成有望成为减轻内皮细胞功能损伤的治疗策略之一。     

Novel therapies targeting vascular endothelium.

Endothelial dysfunction has been identified as a major mechanism involved in all the stages of atherogenesis. Evaluation of endothelial function seems to have a predictive role in humans, and therapeutic interventions improving nitric oxide bioavailability in the vasculature may improve the long-term outcome in healthy individuals, high-risk subjects, or patients with advanced atherosclerosis. Several therapeutic strategies are now available, targeting both the synthesis and oxidative inactivation of nitric oxide (NO) in human vasculature. Statins seem to be currently the most powerful category of these agents, improving endothelial function and decreasing cardiovascular risk after long-term administration. Other cardiovascular agents improving endothelial function in humans are angiotensin-converting enzyme inhibitors/angiotensin receptors blockers, which increase NO bioavailability by modifying the rennin-angiotensin-aldosterone system. Newer therapeutic approaches targeting endothelial dysfunction in specific disease states include insulin sensitizers, L-arginine (the substrate for endothelial NO synthase [eNOS]) as well as substances that target eNOS "coupling," such as folates or tetrahydrobiopterin. Although there are a variety of strategies to improve NO bioavailability in human endothelium, it is still unclear whether they have any direct benefit at a clinical level.