组织蛋白酶S抑制剂影响小鼠缺血诱导的血管新生的机制研究

目的:探讨组织蛋白酶S抑制剂(Cat S-I)影响小鼠缺血诱导的血管新生的机制。方法:将8周龄野生型小鼠(C57/BL6)随机分为两组:对照组(n=20)采用基础饲料饲养基础上再注射5%羧甲基纤维素钠盐,Cat S-I组(n=20)在基础饲料饲养基础上再注射Cat S-I[1 mg/(kg·d)],分别每天1次,共17天。腹腔注射3天后建立下肢缺血模型。用激光多普勒超声血流仪检测下肢血流,计算缺血肢与非缺血肢血流面积比;术后第4天利用免疫蛋白印迹(Western)法检测过氧化物酶增殖物激活受体-γ(PPAR-γ)、磷酸化蛋白激酶B(p-Akt)、磷酸化内皮型一氧化氮合酶(p-e NOS)和血管内皮生长因子(VEGF)等蛋白水平;术后第7天,取缺血骨骼肌作冰冻切片,采用免疫组织化学方法测定毛细血管密度。结果:(1)Cat S-I明显抑制下肢血流的恢复。缺血与非缺血下肢血流比值统计结果显示:Cat S-I组小鼠缺血下肢血流恢复明显慢于对照组(P0.05)。(2)Cat S-I组明显抑制毛细血管的形成。术后第14天非缺血骨骼肌中,与对照组比较,Cat S-I组毛细血管形成略减少,但差异无统计学意义(P0.05);但在缺血骨骼肌中,Cat S-I组小鼠的毛细血管密度明显低于对照组(P0.01)。(3)免疫蛋白印迹法检测结果表明,Cat S-I组小鼠中,PPAR-γ、p-Akt、p-e NOS和VEGF等蛋白表达水平与对照组比较明显减少(P0.05)。结论:Cat S-I调控缺血性血管新生可能与PPAR-γ激活及磷脂酰肌醇激酶(PI3K)/Akt/e NOS信号通路有关。     

不同剂量的阿托伐他汀对心肌损伤大鼠内皮祖细胞动员及血管内皮功能的影响

目的观察不同剂量的阿托伐他汀对心肌损伤后大鼠骨髓和外周血内皮祖细胞动员及血管内皮功能的影响。方法S-D大鼠背部皮肤多点注射异丙肾上腺素(5mg/kg)制造心肌损伤模型后,随机分为生理盐水对照组和不同剂量的阿托伐他汀组[5、10、20、40及80mg/(kg.d)]。4周后,流式细胞仪检测大鼠外周血CD34 和血管内皮生长因子受体2 双阳性细胞数。骨髓和外周血单个核细胞于M199培养基培养,FITC标记的异凝集素和DiI标记的乙酰化低密度脂蛋白染色双阳性细胞为正在分化的内皮祖细胞,倒置荧光显微镜计数3个随机高倍视野数。阿托伐他汀灌胃3天后测定血清一氧化氮浓度。结果阿托伐他汀各剂量组骨髓培养内皮祖细胞均较对照组明显增加(P<0.05),其中40mg/(kg.d)组内皮祖细胞数量最多,较对照组增加了2.4倍(P<0.05),80mg/(kg.d)组与40mg/(kg.d)组比较稍有下降,但无统计学差异;阿托伐他汀组外周血培养内皮祖细胞较对照组明显增加,40mg/(kg.d)组增加最明显(P<0.05);心肌损伤后外周血CD34 /血管内皮生长因子受体2 细胞较损伤前增加(P<0.05),其中80mg/(kg.d)组最明显,较对照组增加了4.18倍(P<0.05),40mg/(kg.d)组与80mg/(kg.d)组无统计学差异;阿托伐他汀各剂量组血清一氧化氮浓度较对照组明显增加,其中80mg/(kg.d)组增加最明显,并随剂量增加一氧化氮浓度增加。结论阿托伐他汀具有显著的剂量依赖性骨髓动员、促进外周血中内皮祖细胞迁移、改善血管内皮功能的作用。     

胰岛素对糖尿病小鼠缺血诱导的血管新生障碍的影响

目的 观察糖尿病小鼠是否存在缺血诱导的血管新生障碍,以及胰岛素治疗对这种障碍的影响,并探讨其可能的分子机制.方法 链脲霉素诱导C57BL/6 雄鼠糖尿病,非糖尿病组给予等量缓冲液,糖尿病胰岛素治疗组术前及术后注射胰岛素控制血糖.左侧股动脉高位结扎离断造成单侧后肢缺血模型.ELISA法测定术前及术后(1、3、7及14天)血浆血管内皮生长因子(VEGF)及间充质衍生因子1α(SDF-1α)水平.CD31免疫组织化学染色法评估术前及术后(7、14天)双侧后肢血管新生情况.免疫印迹法测定腓肠肌组织血管内皮生长因子、内皮型一氧化氮合酶(eNOS)、蛋白激酶B(Akt)及其磷酸化产物的蛋白表达.结果 与非糖尿病组比较,糖尿病组小鼠缺血组织新生毛细血管密度显著减少(术后7天7.65±1.74比18.22±3.77, P<0.05),并伴随缺血诱导的血浆血管内皮生长因子及间充质衍生因子1α释放受抑(P<0.01),靶组织血管内皮生长因子蛋白表达上调受抑,蛋白激酶B及内皮型一氧化氮合酶磷酸化减弱(P<0.05),胰岛素治疗明显改善糖尿病动物组织缺血后血管新生程度(15.36±2.14比7.65±1.74,P<0.05),提高血浆血管内皮生长因子及间充质衍生因子1α释放水平(P<0.01),并增强缺血组织血管内皮生长因子及其下游信号分子的表达与活化(P<0.05).结论 胰岛素治疗有效改善糖尿病动物缺血诱导的血管新生障碍,其可能是通过恢复受损的SDF-1/VEGF/Akt/eNOS信号通路活化而介导.     

下肢缺血“血管新生”的VEGFR-2超声分子成像

目的血管新生是缺血性心血管疾病血流阻塞后改善血流灌注的重要机制。然而,目前临床上尚缺乏一种简单、无创和特异的直接评价血管新生的方法。血管新生时,血管内皮细胞上血管内皮生长因子受体-2(VascularEndothelial Growth Factor Receptor-2,VEGFR-2)的表达明显增加。因此,本研究探讨应用携带VEGFR-2分子探针的超声分子成像评价下肢缺血"血管新生"的可行性。方法 12只实验小鼠予结扎一侧下肢股动脉制备下肢缺血模型,另一侧下肢作为对照组。术后第7天所有小鼠均随机先后(30 min)经尾静脉注入携抗小鼠VEGFR-2单抗的靶向微泡(MBVEGFR-2)和携同型抗体的对照微泡(MBISO),并于8分钟后行对比超声检查,测量双侧下肢的显影强度(video intensity,VI)。最后进行下肢免疫荧光检查。结果对比超声图像显示MBVEGFR-2组缺血下肢可见明显的超声显影,VI值高达(23.7±4.6)U,而在MBISO组缺血下肢仅可见轻度的超声显影,VI值为(6.1±3.2)U,两者之间差异有统计学意义(P<0.05)。但无论MBVEGFR-2还是MBISO,缺血下肢VI值均明显高于非缺血下肢VI值(P<0.05)。两组微泡在非缺血下肢的VI值未见明显差异(P>0.05)。免疫荧光显示缺血下肢血管内皮表达大量的VEGFR-2,而非缺血下肢未见VEGFR-2表达。结论应用VEGFR-2分子探针的超声分子成像可有效评价下肢缺血"血管新生"反应,将为评价治疗性或相关的血管新生提供新的技术手段。     

下肢缺血“血管新生”的VEGFR-2超声分子成像

目的血管新生是缺血性心血管疾病血流阻塞后改善血流灌注的重要机制。然而,目前临床上尚缺乏一种简单、无创和特异的直接评价血管新生的方法。血管新生时,血管内皮细胞上血管内皮生长因子受体-2(VascularEndothelial Growth Factor Receptor-2,VEGFR-2)的表达明显增加。因此,本研究探讨应用携带VEGFR-2分子探针的超声分子成像评价下肢缺血"血管新生"的可行性。方法 12只实验小鼠予结扎一侧下肢股动脉制备下肢缺血模型,另一侧下肢作为对照组。术后第7天所有小鼠均随机先后(30 min)经尾静脉注入携抗小鼠VEGFR-2单抗的靶向微泡(MBVEGFR-2)和携同型抗体的对照微泡(MBISO),并于8分钟后行对比超声检查,测量双侧下肢的显影强度(video intensity,VI)。最后进行下肢免疫荧光检查。结果对比超声图像显示MBVEGFR-2组缺血下肢可见明显的超声显影,VI值高达(23.7±4.6)U,而在MBISO组缺血下肢仅可见轻度的超声显影,VI值为(6.1±3.2)U,两者之间差异有统计学意义(P<0.05)。但无论MBVEGFR-2还是MBISO,缺血下肢VI值均明显高于非缺血下肢VI值(P<0.05)。两组微泡在非缺血下肢的VI值未见明显差异(P>0.05)。免疫荧光显示缺血下肢血管内皮表达大量的VEGFR-2,而非缺血下肢未见VEGFR-2表达。结论应用VEGFR-2分子探针的超声分子成像可有效评价下肢缺血"血管新生"反应,将为评价治疗性或相关的血管新生提供新的技术手段。     

丹红注射液改善糖尿病小鼠下肢缺血血管新生的研究

目的观察丹红注射液对糖尿病小鼠下肢缺血后血管新生的影响。方法 40只Balb/c小鼠,其中10只为正常对照组,30只采用链脲霉素腹腔注射联合左下肢股动脉结扎分离术制备糖尿病下肢缺血模型。模型小鼠中随机选取10只腹腔注射PBS作为Control组,10只腹腔注射丹红注射液作为DH组(2μL/g,连续注射7d)。采用激光多普勒血流灌注扫描仪观察血流灌注情况、动脉X线造影观察血管管样新生情况,及采集下肢肌肉组织匀浆,通过ELISA检测血管内皮生长因子(VEGF)表达量。结果与PBS对照组相比,丹红注射液显著增加糖尿病小鼠下肢缺血血流灌注、管样新生,并提高硫化氢浓度,VEGF表达量显著增高(P0.05)。结论丹红注射液能改善糖尿病小鼠下肢缺血的血管新生,其可能机制是通过VEGF信号通路发挥作用。     

VEGFR-2分子探针超声分子成像评价小鼠下肢缺血性血管新生的可行性

目的探讨血管内皮细生长因子受体(VEGFR)-2分子探针的超声分子成像评价小鼠下肢缺血性血管新生可行性。方法将10只实验小鼠麻醉后结扎一侧下肢股动脉制备下肢缺血模型,术后第7天,所有小鼠随机经尾静脉注入携抗小鼠VEGFR-2靶向微泡(Mb VEGFR-2)和携同型抗体对照微泡(Mbc),并行超声分子检查,测量双下肢的显影强度(VI)值,并处死小鼠后对骨骼肌进行免疫组化检查。结果经过8 min循环时间后,Mb VEGFR-2组小鼠可见明显的超声显影,Mbc组小鼠可见轻度超声显影,但其显影强度明显弱于Mb VEGFR-2组;在非缺血小鼠下肢,经过8 min循环时间后,Mb VEGFR-2组和Mbc组小鼠均未见明显的超声显影;缺血下肢实验小鼠Mb VEGFR-2的VI值明显高于Mbc和非缺血下肢实验小鼠(P<0.01),缺血下肢实验小鼠Mbc的VI值高于非缺血下肢实验小鼠(P<0.05),非缺血下肢骨骼肌VI值在Mb VEGFR-2和Mbc之间差异无统计学意义(P>0.05);DAB染色结果显示下肢缺血小鼠骨骼肌血管有VEGFR-2表达,而下肢非缺血小鼠骨骼肌血管中未见VEGFR-2表达。结论采用携VEGFR-2分子探针的超声成像对缺血下肢新血管进行造影可行,为评价缺血性血管新生提供了病理学依据。     

氟伐他汀对兔髂动脉内皮剥脱后细胞增殖的影响

探讨氟伐他汀对兔髂动脉内皮剥脱后造成的动脉粥样硬化模型中细胞增殖的影响。将雄性新西兰兔随机分为氟伐他汀组 (n =2 8)和对照组 (n =2 8) ,用球囊导管剥脱内皮及高胆固醇饮食造成动脉粥样损伤 ,分别在内皮损伤后 1、2、4、8周处死动物并取髂动脉 ,用常规免疫组织化学染色和计算机图像分析方法观察氟伐他汀对新生内膜中平滑肌细胞增殖和血小板源生长因子 BB的影响。结果发现 ,氟伐他汀组内膜中增殖细胞核抗原染色阳性细胞率明显少于对照组 (P <0 .0 5 ) ;氟伐他汀组血小板源生长因子 BB含量一直处于较低水平 ,且明显低于对照组 (P <0 .0 5 ) ;血管内膜增殖细胞核抗原染色阳性细胞率与血小板衍生因子 BB含量的相关系数为 0 .712 7(P <0 .0 1)。提示氟伐他汀可能部分通过抑制血小板源生长因子 BB合成和分泌而抑制平滑肌细胞增殖。     

低氧诱导因子1α抑制大鼠缺血下肢血管生成及内皮祖细胞的动员

目的探讨低氧诱导因子1α(HIF-1α)在组织缺血时血管生成及内皮祖细胞(EPCs)动员中的作用。方法SD雌性大鼠36只,随机分为下肢缺血加HIF-1α反义寡核苷酸组(HIF-1α反义寡核苷酸组)、下肢缺血加HIF-1α错义寡核苷酸组(HIF-1α错义寡核苷酸组)和单纯下肢缺血组,每组12只,于股动脉结扎建立下肢缺血模型,缺血局部微注射脂质体转染的全硫代修饰HIF-1α寡核苷酸。测血浆血管内皮生长因子(VEGF);acLDL-DiI和FITC-UEA-I双染色鉴定EPCs后计数;下肢缺血区肌肉组织测HIF-1αmRNA和VEGF mRNA的表达和术后28天缺血区肌肉组织毛细血管密度。结果HIF-1α反义寡核苷酸组的HIF-1αmRNA和VEGF mRNA表达均较单纯下肢缺血组和HIF-1α错义寡核苷酸组明显减少;HIF-1α反义寡核苷酸组的循环EPCs、血浆VEGF及缺血区肌肉组织毛细血管密度均较单纯下肢缺血组和HIF-1α错义寡核苷酸组明显减少。结论全硫代修饰HIF-1α反义寡核苷酸可抑制大鼠缺血肢体血管生成和因缺血引起的EPCs的动员,其机制可能是通过VEGF起作用,HIF-1α是组织缺血时EPCs一个动员因子。     

rhEPO保护缺血再灌注大鼠心肌微循环的机制探讨

探讨rhEPO保护缺血再灌注大鼠心肌微循环的机制。将60只雄性SD大鼠随机分为SHAM组,IR组和rhEPO组(n=20),IR和rhEPO组,缺血30min,再灌注1h, 再灌注开始时,IR组腹腔注射0.5ml生理盐水,rhEPO组腹腔注射5000U/Kg的rhEPO(加生理盐水稀释至0.5ml)。ELISA法检测心肌NO和eNOS的含量,Western blot法检测心肌p-Akt和Akt蛋白表达,免疫组化法检测VEGF和CD31的阳性表达,HE染色观察心肌微结构变化,墨汁灌注的方法计数新生血管数。与IR组相比,rhEPO组心肌中NO, eNOS,p-Akt的表达量明显增加(p<0.01),p-Akt/Akt比值明显增大(p<0.01)；VEGF和CD31的表达明显增加(p<0.05)；心肌微结构损伤明显减轻；墨汁灌注的毛细血管数明显增加(P<0.01)。rhEPO保护缺血再灌注大鼠心肌微循环,可能的机制是与PI3K/Akt-eNOS-NO信号途径,促进新生血管的生成相关。     

Gender does not influence angiogenesis and arteriogenesis in a rabbit model of chronic hind limb ischemia

OBJECTIVE: Estrogen administration promotes angiogenesis and perfusion in oophorectomized rabbits with chronic limb ischemia. In the present study we tested whether gender affects angiogenesis and arteriogenesis in a rabbit model of chronic hind limb ischemia. METHODS AND RESULTS: Ischemia was induced in one hind limb of five oophorectomized (Ooph), seven non-oophorectomized (NonOoph) female and eight male New Zealand White rabbits by excision of the femoral artery. Ten days after the induction of ischemia (day 0) and at days 15 and 30 systolic calf blood pressure was measured in the ischemic and non-ischemic hind limbs. Revascularization in the ischemic limb was expressed as ischemic/normal limb blood pressure, capillary/muscle fiber density, and non-capillary, non-lymphatic vessels/muscle fiber density after examination of light microscopic sections taken from the abductor muscle of the ischemic limb at the time of death (day 30). Ischemic/normal blood pressure at day 30 in males was 0.62 +/- 0.22, in NonOoph 0.64 +/- 0.09 (P=ns vs. males) and in Ooph 0.39 +/- 0.05 (P<0.05 vs. males and NonOoph), (F=4.69, P=0.02). Ischemic capillary/muscle fiber in males was 0.96 +/- 0.09, in NonOoph 0.95 +/- 0.06 (P=ns vs. males) and in Ooph 0.83 +/- 0.09 (P<0.05 vs. males and NonOoph), (F=5.93, P=0.01). Ischemic non-capillary, non-lymphatic vessels/muscle fiber density in males was 0.11 +/- 0.02, in NonOoph 0.12 +/- 0.03 (P=ns vs. males) and in Ooph 0.08 +/- 0.02 (P<0.05 vs. NonOoph), (F=5.05, P=0.02). CONCLUSION: Gender does not influence angiogenesis and arteriogenesis in the rabbit model of chronic hind limb ischemia. However, estrogen deficiency induced by oophorectomy negatively affects angiogenesis and arteriogenesis.     

Beneficial effects of supplemental nitric oxide donor given during reperfusion period in reperfusion-induced lung injury

BACKGROUND: Reperfusion injury is a perplexing cause of early graft failure after lung transplantation and today we know that reperfusion may be more harmful to tissues than the preceding ischemia. We hypothesized that administration of the nitric oxide donor nitroglycerin (NTG) during flush perfusion and reperfusion periods would ameliorate reperfusion-induced lung injury. METHODS: Using an IN SITU normothermic ischemic lung rabbit model, three groups were studied (n = 7/group): (1) NTG given during flush perfusion (ischemia group); (2) NTG given in the flush perfusion and the reperfusion period (reperfusion group); and (3) no NTG (control group). All groups were flushed with low potassium dextran glucose solution. Blood gas analysis, tissue nitrite (nitric oxide metabolite) level analysis, bronchoalveolar lavage (BAL) fluid examination and morphological examinations were performed. RESULTS: Compared with the ischemia group, the reperfusion group had significantly improved arterial oxygenation (318 +/- 31.4 mmHg vs. 180 +/- 14.7 mmHg, P < 0.05), decreased BAL fluid neutrophil percentage (21 +/- 1.9 % vs. 30 +/- 5.6 %, P < 0.05), increased tissue nitrite level (32.55 +/- 4.12 nmol/g vs. 27.81 +/- 1.05 nmol/g, P < 0.05), and decreased tissue histopathological lesion scores (0.42 +/- 0.53 vs. 1.14 +/- 0.37, P < 0.05). CONCLUSIONS: This study suggests that nitric oxide donors supplemented during flush perfusion and reperfusion have more beneficial effects on lung functions against reperfusion injury than any other treatment modalities during IN SITU normothermic ischemic lung model.     

Serotonin receptor blockade improves distal perfusion after lower limb ischemia in the fatty Zucker rat

OBJECTIVE: Lower limb perfusion following arterial occlusion depends on the recruitment of collateral vessels. Blood flow through these collateral vessels may be jeopardized by hypersensitivity to vasoconstriction by serotonin (5-HT), as has been reported during hyperlipidemia and diabetes. Therefore the aim of this study was to determine the benefits of chronic treatment with SL65.0472, a mixed 5-HT(1B)/5-HT(2A) receptor antagonist, on lower limb ischemia in fatty fa/fa Zucker rats, a strain characterized by obesity, diabetes and hyperlipidemia. Comparison was made with lean control fa/+ Zucker rats. METHODS: SL65.0472 (3 mg/kg/day, n=16) or its vehicle (n=20) were administered orally for 13 days to male fatty fa/fa Zucker rats submitted to lower limb ischemia. Hindlimb ischemia was induced unilaterally by resection of the left femoral and external iliac arteries and embolization of the left internal iliac artery with microspheres. Distal perfusion was measured under mild anesthesia by laser Doppler imaging of both feet. The perfusion deficit (Delta%) was calculated before and 3, 7 and 14 days after induction of hindlimb ischemia. Twenty-four hours after the last administration of SL65.0472, muscular partial oxygen pressure, iliac blood flows, maximal vasodilatory reserve and the vasoreactivity to 5-HT were measured in both limbs. RESULTS: Chronic administration of SL65.0472 improved the distal perfusion from day 3. At day 14, the deficit of perfusion was limited to -36+/-7% in SL65.0472-treated animals vs. -70+/-6% in the vehicle-treated group (P<0.001) and was accompanied by a significant improvement of partial oxygen pressure in the ischemic limb (SL65.0472: 10.4+/-3.9 mmHg vs. vehicle: 3.5+/-1.1 mmHg, P<0.05). Maximal vasodilatory reserve tended to increase from 2.2+/-0.4 ml/min in the vehicle-treated group to 3.8+/-0.6 ml/min after SL65.0472. SL65.0472 markedly reduced 5-HT-mediated vasoconstriction, which was enhanced in the hypoperfused limb, without altering arterial pressure. Induction of hindlimb ischemia led to the overexpression of both 5-HT(1B) and 5-HT(2A) receptors only in the hypoperfused skeletal muscle as assessed by semi-quantitative RT-PCR. CONCLUSION: These results suggest that the recruitment of collateral vessels after the induction of hindlimb ischemia is significantly impaired in obese fa/fa Zucker rats due to a persistent vasoconstriction mediated by 5-HT and involving stimulation of 5-HT(1B) and/or 5-HT(2A) receptors.     

Hyperbaric oxygen induces basic fibroblast growth factor and hepatocyte growth factor expression, and enhances blood perfusion and muscle regeneration in mouse ischemic hind limbs.

BACKGROUND: It is not clear how hyperbaric oxygen therapy (HBO) affects ischemia-induced pathophysiological responses such as angiogenesis and skeletal muscle regeneration. In the present study the effects of HBO on the functional and morphological recovery of ischemic hind limbs, blood perfusion and the local production of angiogenic growth factors were studied in a mouse model. METHODS AND RESULTS: Mice were placed in pure oxygen under 3 atm for 1 h/day for 14 days after the removal of a segment of the left femoral artery. HBO-treated mice showed better functional recovery and greater blood flow in the ischemic hind limb than untreated mice. Histological examination revealed unatrophied muscle fibers with islands of small regenerating muscle cells only in HBO-treated mice. Regeneration of muscle was confirmed by the increase in myf5 mRNA. The amount of mRNA for vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF) and basic fibroblast growth factor (bFGF) was slightly increased in the ischemic hind limbs. HBO eliminated the increase in VEGF mRNA. In contrast, the amount of mRNA for bFGF and HGF was further increased by HBO treatment. HBO transiently increased early growth response protein 1 (Egr-1) in the ischemic hind limbs. CONCLUSIONS: HBO accelerates the recovery of ischemic hind limbs by increasing the production of bFGF and HGF and by promoting muscle regeneration in mice.     

Effects of ischemic preconditioning on cyclinD1 expression during early ischemic reperfusion in rats

AIM: To observe the effect of ischemic preconditioning on cyclinD1 expression in rat liver cells during early ischemic reperfusion. METHODS: Fifty-four SD rats were randomly divided into ischemic preconditioning group (IP), ischemia/ reperfusion group (IR) and sham operation group (SO). The IP and IR groups were further divided into four sub-groups (n - 6). Sham operation group (SO) served as the control group (n = 6). A model of partial liver ischemia/reperfusion was used, in which rats were subjected to liver ischemia for 60 min prior to reperfusion. The animals in the IP group underwent ischemic preconditioning twice for 5 min each time prior to the ischemia/reperfusion challenge. After 0, 1, 2, and 4 h of reperfusion, serum and liver tissue in each group were collected to detect the level of serum ALT, liver histopathology and expression of cyclinDi mRNA and protein. Flow cytometry was used to detect cell cycle as the quantity indicator of cell regeneration. RESULTS: Compared with IR group, IP group showed a significantly lower ALT level in 1 h to 4 h sub-groups (P < 0.05). Proliferation index(PI) indicated by the S-phase and G2/M-phase ratio [(S G2/M)/(G0/G1 S G2/M)] was significantly increased in IP group at 0 and 1 h (26.44±7.60% vs 18.56±6.40%,41.87±7.27% vs 20.25±6.70%, P < 0.05). Meanwhile, cyclinDi protein expression could be detected in IP group. But in IR group, cyclinDi protein expression occurred 2 h after reperfusion. The expression of cyclinDi mRNA increased significantly in IP group at 0 and 1 h (0.568±0.112 vs 0.274±0.069, 0.762±0.164 vs 0.348±0.093, P < 0.05). CONCLUSION: Ischemic preconditioning can protect liver cells against ischemia/reperfusion injury, which may be related to cell proliferation and expression of cyclinD1 during early ischemic reperfusion.     

Statins augment collateral growth in response to ischemia but they do not promote cancer and atherosclerosis

3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, or statins, are widely prescribed to lower cholesterol. Recent reports suggest that statins may promote angiogenesis in ischemic tissues. It remains to be elucidated whether statins potentially enhance unfavorable angiogenesis associated with tumor and atherosclerosis. Here, we induced hind limb ischemia in wild-type mice by resecting the right femoral artery and subsequently inoculated cancer cells in the same animal. Cerivastatin enhanced blood flow recovery in the ischemic hind limb as determined by laser Doppler imaging, whereas tumor growth was significantly retarded. Cerivastatin did not affect capillary density in tumors. Cerivastatin, pitavastatin, and fluvastatin inhibited atherosclerotic lesion progression in apolipoprotein E-deficient mice, whereas they augmented blood flow recovery and capillary formation in ischemic hind limb. Low-dose statins were more effective than high-dose statins in both augmentation of collateral flow recovery and inhibition of atherosclerosis. These results suggest that statins may not promote the development of cancer and atherosclerosis at the doses that augment collateral flow growth in ischemic tissues.     

Role of neutrophil adherence receptors (CD 18) in lung permeability following lower torso ischemia.

Ischemia and reperfusion of the lower torso lead to leukotriene- and neutrophil (PMN)-dependent lung injury characterized by lung PMN sequestration, increased permeability, and noncardiogenic edema. It is thought that PMNs require adhesion to endothelium to alter barrier function. This study tests the role of CD 18, the PMN adherence receptor, in mediating lung permeability after lower torso ischemia and reperfusion. Anesthetized rabbits (n = 9) underwent 3 hours of bilateral hind limb ischemia. Ten minutes after the release of the tourniquets, plasma leukotriene B4 levels increased to 395 +/- 85 pg/ml, higher than 129 +/- 35 pg/ml in controls (n = 9, p less than 0.01). At this time there was a reduction in circulating white blood cells (x 10(3)), 3.56 +/- 0.49/mm3 relative to 6.07 +/- 0.61/mm3 in controls (p less than 0.01). PMNs were sequestered in the hind limbs, indicated by increased myeloperoxidase activity of 1.06 +/- 0.19 units/g compared with 0.56 +/- 0.09 units/g in controls (p less than 0.05). Four hours after tourniquet release, PMNs were sequestered in the lungs, 52 +/- 4 PMNs per 10 high-power fields, a value higher than 31.5 +/- 3 PMNs per 10 high-power fields in controls; bronchoalveolar lavage fluid protein content increased to 554 +/- 90 micrograms/ml relative to 277 +/- 46 micrograms/ml in controls; and there was lung edema, measured by increased wet weight-to-dry weight ratios of 5.19 +/- 0.10, higher than 4.29 +/- 0.21 in controls (all p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Endothelin-1 and nitric oxide levels in patients with mitral annulus calcification

Mitral annulus calcification (MAC) is a chronic degenerative noninflammatory process. The goal of this study was to determine endothelin-1 (ET-1) and nitric oxide (NOx) levels in patients with MAC and compare them with those in normal subjects. The study group included 39 patients [26 females (66%), age, 63 +/- 8 years] with MAC and 20 [11 females (55%), age, 61 +/- 7 years] healthy subjects. The patients were divided into two subgroups, group A with severe MAC and group B with mild MAC, according to the severity of the MAC. Plasma ET-1 levels were higher and NOx levels were lower in patients than controls [(6.5 +/- 5.6 pg/mL vs 3.7 +/- 2.9 pg/mL for ET-1 and 35.0 +/- 10.6 micromol/L vs 42.3 +/- 9.9 micromol/L for NOx; P < 0.05 for both)]. In the subgroups, ET-1 levels were higher in group A than group B (8.65 +/- 6.84 pg/mL vs 4.74 +/- 3.45 pg/mL, P < 0.05) and the control group (8.65 +/- 6.84 pg/mL vs 3.70 +/- 2.88 pg/mL, P < 0.05). There was no difference between group B and the control group. Plasma NOx levels were significantly decreased in group A compared to controls (32.22 +/- 11.88 micromol/L vs 42.25 +/- 9.99 micromol/L, P < 0.05). However, no significant difference was observed between group B (37.38 +/- 9.06 micromol/L) and the other groups. Diabetes mellitus, coronary artery disease, and dyslipidemia were significantly associated with ET-1 levels. However, this association was not observed for NOx. In conclusion, patients with MAC have increased ET-1 and decreased NOx levels. This seems to be more prominent in patients with severe MAC.     

Angiotensin-converting enzyme inhibition improves defective angiogenesis in the ischemic limb of spontaneously hypertensive rats.

OBJECTIVES: Natural angiogenesis has been shown to be impaired in spontaneously hypertensive rats (SHR). The purpose of this study was to determine whether pathological angiogenesis in the setting of tissue ischemia is also impaired in SHR, and to what extent it is modified by angiotensin-converting enzyme (ACE) inhibition. METHODS: Ischemia was induced in the hindlimb of SHR by excision of the femoral artery, after which the animals were randomly assigned to receive low-dose perindopril (sub-antihypertensive, 0.2 mg/kg/day), high-dose perindopril (antihypertensive, 2.0 mg/kg/day), or vehicle for 3 weeks. Wistar-Kyoto rats (WKY) with femoral artery excision served as a control group. RESULTS: Tissue ACE activity in SHR was significantly increased compared to WKY (49.4+/-6.2 vs. 34.0+/-14.2 IU/mg, P<0.01). Administration of perindopril significantly reduced ACE activity in SHR (low dose: 12.4+/-2.3; high dose: 11.0+/-2.1 IU/mg, P<0.005). Angiogenesis of the ischemic limb muscles was significantly impaired at 4 weeks in SHR versus WKY as indicated by the lower capillary density in the former (364.5+/-43.0 vs. 463.8+/-63.0/mm(2), P<0.05) as well as the reduced hindlimb perfusion assessed by laser Doppler imaging (0.86+/-0.08 vs. 1.03+/-0.09, P<0.05). Administration of perindopril significantly augmented both the capillary density (low dose: 494.3+/-69.8; high dose: 543.9+/-76.9/mm(2), P<0.005) and the limb perfusion (low dose: 1.06+/-0.15; high dose: 1.05+/-0.12, P<0.05) of the ischemic limb in SHR. CONCLUSIONS: These findings indicate that pathological angiogenesis in the setting of tissue ischemia is impaired in SHR compared with WKY, and that this impairment can be reversed by ACE inhibition. The angiogenic properties of an ACE inhibitor may benefit patients with essential hypertension presenting with lower limb vascular insufficiency.