联合促血管生成素-1及血管内皮细胞生长因子基因治疗对大鼠新生血管通透性的影响

目的　探讨联合转染促血管生成素 1(angoipoietin 1,Ang 1)及血管内皮细胞生长因子(vascularendothelialgrowthfactor,VEGF)基因对大鼠下肢新生血管通透性的影响 ,并观察不同基因剂量配比的差异。方法　制造大鼠下肢血管闭塞病理模型 ,按不同剂量配比肌肉内电转pcD2 Ang 1和 或pcD2 VEGF基因。应用逆转录聚合酶链反应、免疫组化染色检测外源基因在骨骼肌中的表达 ,通过伊文思蓝灌注观察其对新生血管通透性的影响。结果　逆转录聚合酶链反应及免疫组化染色均能检测到外源基因的表达。随着转入pcD2 VEGF剂量的增加 ,血管通透性逐渐增加 ;而随着转入pcD2 Ang 1剂量的增加 ,血管通透性逐渐下降。其中pcD2 VEGF 10 0 μg pcD2 Ang 12 0 0 μg组通透性与正常对照最为接近 [( 8 5 7± 0 74 )ng mlvs ( 8 4 2± 0 82 )ng ml,P >0 0 5 ]。结论　联合转pcD2 Ang 1基因可逆转pcD2 VEGF基因增加血管通透性的副作用 ,其中pcD2 VEGF与pcD2 Ang 1比例为 1 2时血管通透性最接近生理状态。与单基因治疗相比 ,适当配比的联合转基因可能成为治疗闭塞性血管病更安全、更有效的新方法。     

肌肉电针介导血管内皮生长因子基因治疗猴闭塞性血管病的实验研究

目的　利用一种新的基因转移方法探讨血管内皮生长因子（ＶＥＧＦ）基因治疗猴闭塞性血管病的可行性。方法构建重组ＶＥＧＦ基因的真核表达载体。转基因前３天肌肉内注入肌肉再生剂了哌卡因（ｂｕｐｉｖａｃａｉｎｅ）,通过电针向血管闭塞症猴（ｎ＝６）骨骼肌内转移重组ＶＥＧＦ基因（１６００μｇ／只）,应用血管造影、局部血管染色及超声多普勒等方法观察ＶＥＧＦ基因导入猴体内后的生物效应,并利用临床自动生化分析仪、病理切片和Ｂ超进行转基因的安全性研究。结果转ｐｃＤ２／ＶＥＧＦ基因２８天后,血管造影可见明显的新生血管和侧支循环形成,超声多普勒发现血流明显恢复,３个月后更显著,血管染色记数两组间差异有显著性（ＰｃＤ２／ＶＥＧＦ组４０．３±９．４３／ｍｍ２;ｐｃＤ２组２５．９±９．００／ｍｍ２,Ｐ＜０．０１）。血液生化测定、主要脏器病理切片和Ｂ超检查未发现异常。结论利用电针向肌肉内转移ＶＥＧＦ基因可促进局部组织新生血管形成和侧支循环建立,促进血流恢复,且安全、简便,为闭塞性血管病的基因治疗提供一种新的基因转移方法。     

人血管内皮细胞生长因子-165和人血管生成素-1促进大鼠缺血下肢血管新生

目的　观察肌肉转染腺病毒(adenovirus ,Ad )携带的人血管内皮细胞生长因子- 1 6 5(ves cularendothelialgrowfactor ,Ad5 VEGF1 65)和人血管形成素- 1 (angiopoietin- 1 ,Ad5 Ang -1 )基因对大鼠缺血下肢的生血管效应。方法　制作大鼠下肢血管闭塞模型,肌肉内注射Ad5 VEGF1 65 或 和Ad5 Ang -1 ,以Westernblot法检测生长因子蛋白表达,免疫组化检测基因导入后在缺血肌肉引起的效应。结果　肌肉经注射Ad5 VEGF1 65和Ad5 Ang- 1后高表达人VEGF1 65 蛋白和人Ang- 1蛋白。术后7d处理组与对照组新生毛细血管数目无明显差别。但术后1 4d和2 1dAng- 1和VEGF1 65 组的新生毛细血管 肌肉数目比明显高于对照组(P <0 . 0 1 ) ,VEGF1 65 Ang 1两因子合用组明显高于单用组(P <0. 0 1 )。Ad -VEGF1 65组及Ad VEGF1 65 Ad Ang 1合用组出现大量包围着一厚层αSMA阳性平滑肌细胞的血管,其数量与肌肉数比值明显高于对照组(P <0 . 0 1 )。因子单用组和合用组肌肉内出现大量溴化脱氧尿嘧啶阳性细胞浸润,部分细胞表面呈现C- Kit阳性,新生血管内皮细胞中也有C Kit阳性标记。结论　Ad5- VEGF1 65和Ad5 -Ang -1能促进缺血肢体血管新生,二者合用的生血管效应更为显著;VEGF1 65能促进包被平滑肌细胞的形似微小动脉的血管数量增多     

血管内皮生长因子基因治疗小型猪冠状动脉闭塞的实验研究

目的探讨应用血管内皮生长因子(VEGF)基因治疗动物实验性冠状动脉闭塞的疗效.方法中国实验用小型猪19只,结扎左冠状动脉前降支中远段,心肌内多点注射自行构建的pcD2/hVEGF121真核表达质粒.应用逆转录聚合酶链反应、VEGF免疫组化染色、Ⅷ因子相关抗原免疫组化染色等方法检测VEGF基因在心肌中的表达及其生物学作用,用常规冠状动脉造影观察VEGF基因治疗对闭塞冠脉侧支循环建立的作用.结果转移VEGF基因后,小型猪心肌内VEGF mRNA高表达,VEGF免疫组化染色提示VEGF蛋白表达水平升高;Ⅷ因子相关抗原免疫组化染色显示心肌毛细血管增加;冠状动脉造影证明VEGF基因治疗能够促进闭塞冠脉侧支循环的建立.结论心肌内注射pcD2/hVEGF121真核表达质粒能够获得VEGF mRNA和蛋白的有效表达,促进心肌毛细血管增生,促进侧支循环建立.     

促血管生成素1和血管内皮生长因子基因合适剂量配比有效促进血管生成

目的在大鼠后肢缺血模型中,探讨联合转染促血管生成素1和血管内皮生长因子基因治疗对新生血管数量和侧支循环形成的影响,并观察不同基因剂量配比对新生血管形态和功能的影响。方法制备大鼠后肢血管闭塞病变模型,采用电脉冲法介导转基因,按不同剂量配比进行肌肉组织转染携带促血管生成素1基因的质粒和/或携带血管内皮生长因子基因的质粒。采用逆转录聚合酶链反应检测外源基因的表达、免疫组织化学染色检测缺血局部毛细血管和小动脉的数量和分布、通过后肢血管造影检测侧支循环建立的情况。结果单独转促血管生成素1基因或血管内皮生长因子基因治疗组血管生成数量略有增加,联合基因治疗组中,血管内皮生长因子质粒剂量为100μg时,随着促血管生成素1质粒剂量的增加,小动脉计数较同期空载质粒对照组分别增加0.90倍、1.40倍和1.45倍;当促血管生成素1质粒剂量为100μg时,随着血管内皮生长因子质粒剂量的增加,小动脉计数较同期空载质粒对照组分别增加1.90倍、1.07倍和1.39倍。血管通透性检测表明,随着血管内皮生长因子质粒剂量的增加,血管通透性渐增加,促血管生成素1质粒能降低新生血管的通透性;其中促血管生成素1质粒200μg联合血管内皮生长因子质粒100μg组在有效促进小动脉形成的同时血管通透性与正常对照组最为接近。结论联合血管生成素1和血管内皮细胞生长因子基因治疗能更有效促进小动脉形成,其中血管内皮生长因子质粒与促血管生成素1质粒比例为1:2时血管通透性最接近生理状态,是比较理想的联合基因治疗剂量配比。     

人脑胶质瘤细胞系Ang-2基因转染及其与肿瘤血管生成的关系

用促血管生成素-2（Ang-2）基因转染人脑胶质瘤H4细胞系，并用RT-PCR、Western blot技术鉴定H4细胞Ang-2基因及蛋白的表达。将转染后的细胞接种于裸鼠皮下。观察肿瘤生长的速度并对肿瘤组织进行徽血管密度（MVD）检测。结果显示H4细胞中有Ang-2基因的表达。转染Ang-2基因后肿瘤生长速度明显加快，肿瘤组织中血管生成的数量较空载体组及空白对照组明显增多。表明Ang-2基因转染H4胶质瘤细胞后，增强了肿瘤细胞的体内成瘤性，并能促进肿瘤组织的血管生成。     

VEGF、Ang-2形成中的作用在Graves病血管形成中的作用

采用S—P免疫组织化学法检测35例Graves病患者甲状腺组织切除标本（观察组）和11例甲状腺良性腺瘤患者的正常甲状腺组织（对照组）中血管内皮生长因子（VEGF）、促血管生成素-2（Ang-2）蛋白的表达和CD34标记的微血管密度（MVD），并分析其相关性。结果 观察组VEGF、Ang-2的表达程度明显高于对照组（P均〈0．05）;观察组VEGF蛋白表达与Ang-2蛋白表达呈显著正相关（r=0.351，P〈0．05）．二者的表达程度与MVD亦均呈显著正相关（r分别为0．723、0．675，P均〈0．01）。提示VEGF、Ang-2表达在Graves病甲状腺血管形成中起重要作用。     

血管内皮生长因子基因治疗犬闭塞性血管病的初步研究

目的探讨血管内皮生长因子（ＶＥＧＦ）基因治疗犬闭塞性血管病的可行性，并对其安全性进行初步观察。方法构建了重组ＶＥＧＦ基因的真核表达载体。在基因转移前３天，肌肉内注射肌肉再生剂丁哌卡因（ｂｕｐｉｖａｃａｉｎｅ），并通过基因缝线和直接注射法，向血管闭塞症犬（ｎ＝５）的肌肉内转移重组ＶＥＧＦ基因（０．５ｍｇ／ｋｇ），应用ＲＴ－ＰＣＲ技术观察ＶＥＧＦ基因的表达，通过血管造影观察ＶＥＧＦ基因导入犬体内的生物效应；并应用临床自动血液生化分析仪和眼底镜进行转基因的安全性观察。结果转ｐｃＤＮＡ３／ＶＥＧＦ基因２８天后，缺血区肌肉组织内ＶＥＧＦ的表达明显高于对照单纯转ｐｃＤＮＡ３组；１４天后血管造影可见明显新生血管和侧枝循环的形成，２８天后更明显，一年后未见血管无限制生长；血液生化测定未见明显副作用。结论肌肉内转移ＶＥＧＦ基因通过促进血管新生和侧枝循环建立，促进血流恢复，经一年连续观察，无明显毒副作用，为闭塞性血管病的治疗，提供一种新的有效方法。     

Ang-2在食管鳞癌血管生成中的作用

应用免疫组化SP法检测食管鳞癌及食管断端正常鳞状上皮中促血管生成素（Ang）-2、血管内皮生长因子（VEGF）的表达，以及CD105标记的微血管密度（MVD）。结果显示，Ang-2蛋白表达主要定位于肿瘤细胞的胞质和胞膜，尤其是癌灶边缘血管重建区。食管鳞癌组织中Ang-2和VEGF蛋白表达显著高于食管断端正常鳞状上皮（P〈0．01），癌组织中Ang-2表达程度与VEGF表达程度及MVD呈明显正相关（P〈0．01，〈0．05）。提示食管鳞癌组织中Ang-2高水平表达可能促进肿瘤新生血管形成．促进食管鳞癌的发生发展。     

白藜芦醇对AMI后心脏血管新生及冠脉侧支循环影响的实验研究

目的 进一步观察白藜芦醇对急性心肌梗死（AMI）后心血管系统保护作用的机制.方法 将32只新西兰大耳兔随机分为四组各8只, B、C、D组通过结扎左冠脉前降支建立AMI模型,A组（假手术组）除不结扎动脉外余步骤同上.术后24 h A、B组予生理盐水灌胃,C组予长效消心痛＋生理盐水灌胃,D组予白藜芦醇＋生理盐水灌胃.各组均持续给药15 d后处死,留取心肌标本,于-80 ℃保存或4%福尔马林固定后制作石蜡切块,检测心肌梗死面积及梗死边缘区心肌组织微血管密度（MVD）、血管内皮生长因子（VEGF）、促血管生成素-1（Ang-1）表达.结果 C组及D组心肌梗死面积明显小于B组,梗死边缘区MVD及VEGF、Ang-1表达明显高于B组（P均〈0.05）,D组Ang-1表达显著高于C组（P〈0.05）.结论 白藜芦醇可促进AMI后心脏血管新生及冠脉侧支循环形成,可作为不能耐受硝酸酯类药物且不适于介入、外科搭桥术冠心病患者的替代药物.     

Revascularization in the rabbit hindlimb: dissociation between capillary sprouting and arteriogenesis

OBJECTIVE: Animal models of hindlimb ischemia are critical to our understanding of peripheral vascular disease and allow us to evaluate therapeutic strategies aimed to improve peripheral collateral circulation. To further elucidate the processes involved in revascularization following ischemia, we evaluated the temporal association between tissue ischemia, vascular endothelial cell growth factor (VEGF) release, angiogenesis (capillary sprouting), arteriogenesis (growth of the larger muscular arteries), and reserve blood flow (functional collateral flow). METHODS: New Zealand White rabbits (male 3-4 kg) were evaluated at specific days (0, 5, 10, 20 or 40) following femoral artery removal for measurement of hindlimb blood flow, skeletal muscle lactate production and VEGF content, capillary density (a marker of angiogenesis), and angiographic score (a marker of arteriogenesis). RESULTS: Maximal capillary sprouting occurred within 5 days of femoral artery removal and was temporally associated with reduced resting hindlimb blood flow, increased lactate release and detectable levels of skeletal muscle VEGF. The growth of larger angiographically visible collateral vessels occurred after 10 days and was not temporally associated with ischemia or skeletal muscle VEGF content, but did coincide with a large functional improvement in the reserve blood flow capacity of the limb. CONCLUSIONS: Following femoral artery removal in the rabbit, the time course of angiogenesis and arteriogenesis were clearly distinct. Tissue ischemia and/or VEGF may stimulate capillary sprouting, but this response does not translate to a significant improvement in collateral flow. The growth and development of the larger collateral vessels was correlated with a large functional improvement in collateral flow, and occurred at a time when VEGF levels were undetectable.     

Hyperhomocysteinemia impairs angiogenesis in response to hindlimb ischemia

Hyperhomocysteinemia (HH) is an independent risk factor for atherosclerosis, including peripheral arterial occlusive disease (PAOD). Because angiogenesis and collateral vessel formation are important self-salvage mechanisms for ischemic PAOD, we examined whether HH modulates angiogenesis in vivo in a rat model of hindlimb ischemia. Rats were divided into 3 groups: the control group was given tap water, the HH group was given water containing L-methionine (1 g x kg(-1) x d(-1)), and the HH+L-arg group was given water containing methionine (1 g x kg(-1) x d(-1)) and l-arginine (2.25 vol%). At day 14 of the dietary modifications, the left femoral artery and vein were excised, and the extent of angiogenesis and collateral vessels in the ischemic limb were examined for 4 weeks. Plasma homocysteine levels significantly increased (P:<0.001), and plasma and tissue contents of nitrite+nitrate as well as tissue cGMP levels significantly decreased in the HH group compared with the control group (P:<0.01). Laser Doppler blood flowmetry (LDBF) revealed a significant decrease in the ischemic/normal limb LDBF ratio in the HH group at days 7, 14, 21, and 28 (P:<0.01 versus control). Angiography revealed a significant decrease in the angiographic score in the HH group at day 14 (P:<0.001 versus control). Immunohistochemistry of ischemic tissue sections showed a significant reduction in the capillary density in the HH group (P:<0. 001 versus control). Oral l-arginine supplementation in rats with HH (HH+L-arg) restored the decreased plasma and tissue nitrite+nitrate and cGMP contents (P:<0.05) as well as angiogenesis, as assessed by LDBF (P:<0.05 versus HH), angiographic score (P:<0.01 versus HH), and capillary density (P:<0.001 versus HH). In summary, HH impaired ischemia-induced angiogenesis and collateral vessel formation in a rat model of hindlimb ischemia in vivo. The mechanism of the HH-induced impairment of angiogenesis might be mediated in part by a reduced bioactivity of endogenous NO in the HH state.     

过量服用蛋氨酸所致高同型半胱氨酸血症对缺血性血管新生的抑制作用

高同型半胱氨酸血症是引起动脉粥样硬化的一种独立危险因素。过量服用蛋氨酸会导致血清中同型半胱氨酸浓度增高、内皮功能受损、血管舒缩功能减弱。本研究使用过量服用蛋氨酸导致高同型半胱氨酸血症大鼠，与对照组比较，观察缺血下肢血管新生的情况，判断高同型半胱氨酸血症对缺血性血管新生的影响。将36只雄性Sprague-Dawley大鼠分为两组：对照组和高同型半胱氨酸血症组。对照组始终给予自来水；高同型半胱氨酸血症组则给予含有0．5％蛋氨酸的饮水。两组动物分别按上述方法给予不同饮水2周后，手术切除左侧股动、静脉，观察缺血28d内缺血区域血管新生和侧枝血管形成的情况。过量服用蛋氨酸导致的高同型半胱氨酸血症减弱了大鼠下肢慢性缺血性血管新生和侧枝血管的建立，这可能与高同型半胱氨酸血症减弱内皮源性一氧化氮生物活性有关。     

Enhanced hindlimb collateralization induced by acidic fibroblast growth factor is dependent upon femoral artery extraction

Recent investigations have established the feasibility of using exogenously delivered angiogenic growth factors to increase collateral artery development in animal models of myocardial and hindlimb ischemia. OBJECTIVE: Our aim was to evaluate the ability of a stabilized form of acidic fibroblast growth factor (aFGF-S117) to stimulate collateralization and arteriogenesis in the rabbit hindlimb following the surgical induction of ischemia by femoral artery extraction. A secondary objective was to examine angiogenic and arteriogenic effects of aFGF-S117 in the absence of a peripheral blood flow deficit. METHODS AND RESULTS: Five days after femoral artery removal, aFGF-S117 (1, 3, or 30 microg/kg) was intramuscularly delivered into the hindlimb, three times per week for 2 consecutive weeks. End-point measurements performed on day 20 found that hindlimb reserve blood flow was significantly improved in rabbits that received 3 or 30 microg/kg of aFGF-S117, with no difference in efficacy between these two doses. These hemodynamic results were supported by angiographic evidence showing enhanced density of collateral vessels in the medial thigh region and histological findings of increased capillary density within the gastrocnemius muscle from rabbits treated with aFGF-S117. When an efficacious dose of 3 microg/kg of aFGF-S117 was administered to sham-operated rabbits with intact femoral arteries, there was no change in any of the blood flow, angiographic or histological parameters measured. CONCLUSIONS: These findings demonstrate that a stabilized form of aFGF stimulated the development of functional collateral arteries in the rabbit hindlimb, an effect which was dependent upon removal of the femoral artery. These results suggest that aFGF-S117 may have therapeutic potential for the treatment of arterial occlusive disorders.     

Vascular endothelial growth factor stimulates angiogenesis without improving collateral blood flow following hindlimb ischemia in rabbits

This study was designed to test the ability of adenovirus-delivered vascular endothelial growth factor (Ad-VEGF) to stimulate angiogenesis and arteriogenesis in the rabbit hindlimb following the induction of ischemia and to evaluate the functional changes in the collateral circulation. Ten days after the surgical induction of hindlimb ischemia, either a control virus (1 × 10⁹pfu) or an adenovirus containing the gene for VEGF₁₆₅ (1 × 10⁶, 1 × 10⁷, 1 × 10⁸, or 1 × 10⁹pfu) was administered intramuscularly into the ischemic limb. Thirty days after administration of the adenoviral vectors, skeletal muscle capillary density was assessed and angiography was performed as markers of angiogenesis and arteriogenesis, respectively. Hindlimb blood flow was directly measured and hyperemic tests were performed to evaluate the functional improvements in collateral blood flow. Animals treated with Ad-VEGF at 1 × 10⁸ and 1 × 10⁹pfu showed elevated levels of circulating VEGF and dose-dependent hindlimb edema. These doses also led to a robust angiogenic response (i.e., increase in capillary density), but failed to improve collateral blood flow. Consistent with the lack of a functional response, there was no angiographic evidence of enhanced arteriogenesis with any dose of Ad-VEGF. Following the induction of hindlimb ischemia, administration of Ad-VEGF stimulated capillary sprouting (i.e., angiogenesis), but did not increase the growth and development of larger conduit vessels (i.e., arteriogenesis) or improve collateral blood flow. These results support the concept that VEGF may not be expected to have therapeutic utility for the treatment of peripheral or myocardial ischemia.     

Conduction performance of collateral vessels induced by vascular endothelial growth factor or basic fibroblast growth factor

OBJECTIVE: In the present study, we delivered vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) gene to a rabbit model of hind limb ischemia utilizing an ex vivo method of gene transfer, and evaluated the functional performance of the developed collateral vessels. METHOD: The left femoral artery of a male Japanese White rabbit was excised to induce limb ischemia, and a section of skin was resected for culture of auto-fibroblasts. Twenty days later, the VEGF gene, bFGF gene or beta-galactosidase gene (LacZ) was adenovirally transferred to the cultured auto-fibroblasts (5x10(6) cells), and the next day, a pair of specifically infected fibroblasts (total 1x10(7) cells) was injected via the left internal iliac artery of the same rabbit. Pairs of transferred genes into the fibroblasts were as follows: LacZ/LacZ (control group), VEGF/LacZ (VEGF group), bFGF/LacZ (FGF group) and VEGF/bFGF (combination group). Twenty-eight days after cell administration, collateral development and its function were evaluated. RESULTS: Calf blood pressure ratio, resting blood flow of the left iliac artery and capillary density of ischemic muscle showed similar degrees of angiogenic effects in the VEGF and FGF groups, which were significantly greater than those in the control group. On the contrary, angiographic score, collateral conductance and smooth muscle cell (SMC)-positive vessel density in the FGF group were significantly greater than those in the VEGF group. In the combination group, collateral conductance showed synergistic effects, and in vivo blood flow and smooth muscle cell-positive vessel density revealed additive effects of VEGF and bFGF. CONCLUSION: These findings suggested that bFGF-induced collateral development exceeded VEGF-induced collateral development in the induction of arteriogenesis, and that combined gene delivery of VEGF and bFGF produced additive or synergistic effects of collateral development as compared with the effects induced by transfer of each gene alone.     

Effects of gene delivery on collateral development in chronic hypoperfusion: diverse effects of angiopoietin-1 versus vascular endothelial growth factor

OBJECTIVES: The aim of this research was to test the effects of vascular endothelial growth factor (VEGF)/angiopoietin-1 (Ang-1) on adult hypoperfused tissues. BACKGROUND: Angiopoietin-1 and VEGF act separately and synergistically in vascular development during embryogenesis. However, little is known regarding their relative roles in collateral development after chronic arterial obstruction and tissue ischemia in the adult. METHODS: Central and caudal ear arteries of 32 rabbits were ligated to induce ischemia. At two months, when flow was about 65% of pre-ligation values, we injected intradermally 10(9) plaque-forming unit adenovirus with the following transgenes: Ang-1, VEGF, or a combination of both. Ear perfusion was followed up for four weeks, and vessel leakage was assessed by Evens Blue test. RESULTS: Before injection, flow was 65% of baseline, and endogenous VEGF levels in ischemic tissue were increased. Adenovirus-encoding VEGF gene (Ad.VEGF) at one week caused a visible inflammatory response associated with a 24% flow increase (p = 0.018). Adenovirus-encoding Ang-1 gene (Ad.Ang-1) increased flow 22% (p = 0.004) with no visible inflammation; Ad.VEGF caused three times as much vessel leakage as Ad.Ang-1 (142.5 +/- 38 vs. 49.5 +/- 9.8 ng Evens Blue/mg tissue; p < 0.001). However, at four weeks, compared with baseline, VEGF decreased flow 18% (p = 0.004), whereas Ang-1 increased tissue perfusion 26% (p < 0.001). This effect was abolished when Ad.Ang-1 was injected with soluble VEGF receptor [Ad.Flt(1-3)-Fc], which blocks VEGF-dependent signaling. Exogenous Ang-1 did not increase perfusion in a normally perfused ear, in which endogenous VEGF is not expressed. CONCLUSIONS: Exogenous Ang-1 enhances perfusion in hypoperfused tissues only in the presence of increased levels of endogenous VEGF. Overexpression of VEGF, however, after causing an inflammatory response, does not improve collateral blood flow.     

Roles of endogenous monocyte chemoattractant protein-1 in ischemia-induced neovascularization

OBJECTIVES: We sought to investigate the role of endogenous monocyte chemoattractant protein (MCP)-1 in ischemia-induced neovascularization. BACKGROUND: Roles of inflammatory changes including macrophage infiltration are suggested in ischemic neovascularization. METHODS: Unilateral hindlimb ischemia was induced by excising surgically the entire femoral artery and vein in mice. Immediately after operation, plasmid deoxyribonucleic acid encoding a dominant negative mutant of MCP-1 (7ND) or the empty plasmid (mock) was injected into the ipsilateral thigh adductor muscle. RESULTS: In mock-treated mice, MCP-1 was upregulated transiently in ischemic hindlimb peaking at day 3. Serial laser Doppler blood flow (LDBF) analysis showed an abrupt decrease in blood flow, followed by a recovery to the near-normal levels in mock-treated mice; 7ND treatment had no effects on the initial decrease in LDBF but deteriorated the recovery. At day 3, macrophage infiltration and inductions of tumor necrosis factor (TNF)-alpha and vascular endothelial growth factor (VEGF) were prominent in the ischemic adductor muscle in mock-treated mice; 7ND treatment significantly reduced macrophage infiltration and suppressed TNF-alpha and VEGF inductions in response to ischemia. At day 21, postmortem angiography and anti-CD31 immunohistostaining revealed well-developed collateral vessels and capillary formation, respectively, in the ischemic muscle of mock-treated mice; 7ND overexpression remarkably suppressed the collateral vessel formation and capillary formation. CONCLUSIONS: Endogenous MCP-1 may play a role in ischemia-induced neovascularization by recruiting macrophages that activate TNF-alpha and VEGF inductions.     

Quantification of collateral flow in humans: a comparison of angiographic, electrocardiographic and hemodynamic variables

OBJECTIVES: Evaluation of collateral vascular circulation according to hemodynamic variables and its relation to myocardial ischemia. BACKGROUND: There is limited information regarding the hemodynamic quantification of recruitable collateral vessels. METHODS: Angiography of the donor coronary artery was performed before and during balloon coronary occlusion in 63 patients with one vessel disease. Patients were divided into groups of those with an absence of collateral vessels (group 1, n = 10), those with recruitable collateral vessels (group 2, n = 23) and those with spontaneously visible collateral vessels (group 3, n = 30). During balloon inflation the coronary wedge/aortic pressure ratio (Pw/Pao) was determined as were collateral blood flow velocity variables, using a 0.014" Doppler guide wire. Myocardial ischemia was defined as > or =0.1 mV ST-shift on a 12 lead electrocardiogram at 1 min coronary occlusion. RESULTS: Myocardial ischemia was present in all patients of group 1, in 14 patients of group 2 and in 3 patients of group 3. Recruitable collateral flow without ischemia showed similar hemodynamic values as in group 3 while these values were similar to group 1 in regard to the presence of recruitable collateral vessels showing ischemia. Logistic regression analysis revealed both Pw/Pao and Vi(col) as independent predictors for the function of collateral vessels. CONCLUSIONS: Hemodynamic variables of collateral vascular circulation are better markers of the functional significance of collateral vessels than is coronary angiography. The total collateral blood flow velocity integral and coronary wedge/aortic pressure ratio are good and independent predictors of the function of collateral vessels producing complementary information.     

Angiopoietin-2 impairs revascularization after limb ischemia

Angiopoietins play important roles in the formation of neovessels and complex vascular networks. Angiopoietin (Ang)-1 and Ang-2 belong to a family of growth factors that display opposing effects on the activation of Tie2 (tyrosine kinase with immunoglobulin and epidermal growth factor homology domain 2). Endothelial Ang-2 expression is associated with vessel destabilization and regulates a balance between vascular regression and growth. To elucidate, in particular, the role of Ang-2 after arterial artery occlusion in the mouse limb, we applied a transgenic animal model with targeted Ang-2 expression in endothelial cells. We show here that restoration of blood flow in Ang-2:Tie1 transgenic mice is dramatically impaired when Ang-2 expression is induced in the vasculature. The defective restoration of perfusion in Ang-2 transgenic mice is evidenced by reduced collateral artery growth, which typically occurs to compensate for flow deficits after occlusion of the large conductance artery. Furthermore, reduced movement capacities and higher incidents of necrosis are consequently observed in the transgenic limbs as compared with controls. Mechanistically, the observed effects are attributed to defective smooth muscle cell recruitment in Ang-2 transgenic mice. Moreover, distinct Ang-2 levels in the genetically modified animals clearly correlated with the magnitude of reduced perfusion. In conclusion, our studies define Ang-2 as an important molecule for the progression of collateral artery growth and angiogenesis during ischemia and suggest precise Ang-2 dosage activities to accomplish blood vessel growth.