高同型半胱氨酸血症对血管损伤后新生内膜形成的作用及机制

目的研究饮食诱导的高同型半胱氨酸血症(Hcy)对血管损伤后新生内膜形成的作用及机制。方法采用1g(kg·d)L蛋氨酸灌胃制备Hcy大鼠模型。4周后行左颈动脉拉伤,第14天、第28天取材,检测新生内膜的形成、内皮覆盖和平滑肌细胞增殖情况。结果第14天、第28天高蛋氨酸饮食(HHCY)组比对照组新生内膜增生厚度分别增加36%和33%,新生内膜面积分别增加41%和30%,新生内膜面积与中膜面积之比分别增加36%和21%,管腔面积分别减少47%和61%,中膜面积无明显差别。第14天HHCY组内膜、中膜增殖细胞核抗体阳性颗粒百分比是对照组的1.7倍和2.3倍。第14天、第28天HHCY组血管内皮覆盖率比对照组减少52%和31%。结论高同型半胱氨酸血症促使血管损伤后新生内膜形成,促进平滑肌细胞增殖和抑制内皮修复是其致病机制,提示高同型半胱氨酸血症可能是血管成形术后再狭窄发生的重要的危险因素之一。     

高同型半胱氨酸血症大鼠冠状动脉内皮细胞单核细胞趋化蛋白1的表达

目的观察高同型半胱氨酸血症对大鼠冠状动脉内皮细胞表达单核细胞趋化蛋白1的影响,以明了冠状动脉粥样硬化性心脏病的发病机制。方法24只大鼠随机分成正常饮食对照组、高蛋氨酸饮食组、高蛋氨酸 叶酸饮食组、高半胱氨酸饮食组。每组6只,分别给予普通饲料;普通饲料加1.7%蛋氨酸;普通饲料加1.7%蛋氨酸和0.006%叶酸;普通饲料加1.2%半胱氨酸。饲养6周,采用高效液相色谱荧光检测法测定血浆总同型半胱氨酸浓度,免疫组织化学染色法检测大鼠冠状动脉左主干和左前降支内皮细胞单核细胞趋化蛋白1的表达。结果喂以高蛋氨酸饲料6周,可诱导大鼠高同型半胱氨酸血症。与正常饮食对照组比较,高蛋氨酸饮食组大鼠血浆总同型半胱氨酸浓度显著升高(P<0.01),冠状动脉内皮单核细胞趋化蛋白1的表达水平明显增强;高蛋氨酸 叶酸饮食组大鼠血浆总同型半胱氨酸水平较高蛋氨酸饮食组显著降低(P<0.01),其冠状动脉内皮单核细胞趋化蛋白1的表达水平也降低;高半胱氨酸饮食组大鼠血浆总同型半胱氨酸浓度,以及冠状动脉内皮单核细胞趋化蛋白1的表达水平与正常饮食对照组比较差异无显著性。结论高同型半胱氨酸血症促进了大鼠冠状动脉内皮细胞表达单核细胞趋化蛋白1,在冠状动脉粥样硬化性心脏病的发生和发展中起着重要的作用。     

高同型半胱氨酸血症致血管炎症作用

目的 探讨高同型半胱氨酸血症是否引发兔主动脉的血管炎症反应。方法 20只雄性新西兰兔随机分成对照组（正常饮食）和蛋氨酸组（高蛋氨酸饮食），每组各10只，12周后测定血浆同型半胱氨酸。观察主动脉病理变化，酶联免疫吸附法检测白细胞介素8蛋白水平，免疫组织化学检测血管核因子κB的表达和活化。结果 高蛋氨酸饮食显著增加血浆同型半胱氨酸水平，蛋氨酸组主动脉切片发现内皮细胞脱落，局部内膜增厚；白细胞介素8分泌增加；主动脉内皮细胞核因子κB表达增强。结论 高同型半胱氨酸血症可以导致血管炎症反应。而炎症反应是高同型丰胱氨酸血症加速动脉粥样硬化潜在的分子机制之一。     

4,5,7-三羟异黄酮减轻高同型半胱氨酸血症导致的血管内皮损伤

目的观察植物雌激素4,5,7-三羟异黄酮(GST)对同型半胱氨酸(Hcy)诱导的血管内皮损伤的保护作用。方法健康成年雌性Wistar大鼠随机分成4组:对照组;2.5%蛋氨酸饮食组;卵巢去势+2.5%蛋氨酸饮食组;卵巢去势+2.5%蛋氨酸饮食+GST治疗组,每组8只。给予大鼠高蛋氨酸(2.5%)饮食来复制高同型半胱氨酸血症(HHcy)模型,卵巢去势+2.5%蛋氨酸饮食组和卵巢去势+2.5%蛋氨酸饮食+GST治疗组大鼠施行卵巢去势手术,GST以2.5 mg/(kg.d)剂量灌胃给药。治疗12周以后,颈总动脉采血,检测血浆中雌二醇和Hcy的水平。分离大鼠胸主动脉环,检测血管环对苯肾上腺素(PE),乙酰胆碱(Ach)和硝普钠(SNP)的反应性以评价血管功能;HE染色观察胸主动脉壁形态学的改变。体外培养内皮细胞株Eahy926,观察GST体外干预对Hcy诱导内皮细胞损伤的作用。结果高蛋氨酸饮食能够导致大鼠血浆Hcy水平显著升高,出现明显血管内皮功能和形态损伤,卵巢去势进一步加重了血浆Hcy水平的升高和血管内皮损伤。GST治疗12周能够明显减轻去卵巢HHcy大鼠的血管内皮的功能和形态损伤,而且能够降低血浆中Hcy水平;G...     

麝香保心丸对高同型半胱氨酸血症大鼠内皮功能的影响

目的在大鼠高同型半胱氨酸血症(HHcy)模型上,探讨麝香保心丸对血管内皮功能的影响。方法将24只雄性SD大鼠随机分为正常对照组、HHcy组及HHcy+麝香保心丸组,每组8只。采用酶联免疫吸附法(ELISA)检测血浆同型半胱氨酸(Hcy)水平,采用硝酸还原酶法检测大鼠血浆一氧化氮(NO)含量,采用免疫组织化学法检测主动脉一氧化氮合成酶(eNOS)表达。结果 L-蛋氨酸灌胃能够诱导大鼠HHcy模型,使血浆NO含量减少,血管内皮eNOS表达同步下调;采用麝香保心丸干预后,内皮功能有所改善。结论麝香保心丸可改善HHcy引起的内皮功能障碍。     

高同型半胱氨酸血症兔模型动脉粥样硬化的形成

为评价兔高同型半胱氨酸血症模型的建立及其对动脉粥样硬化形成的影响，采用含1%蛋氨酸饮食饲养新西兰大白兔，并与高脂模型和正常组比较，动态分析各组血清中同型半胱氨酸的变化及动脉粥样硬化形成的情况。结果发现，给予1%蛋氨酸负荷，4周即可观察到明显的高同型半胱氨酸血症发生;8周时可见明显的血管狭窄和动脉粥样硬化斑块形成等变化。结果提示，采用新西兰大白兔给予1%蛋氨酸饮食负荷是一种较为可靠的造高同型半胱氨酸血症模型的方法；高同型半胱氨酸血症是动脉粥样硬化形成的一个独立危险因素。     

高同型半胱氨酸血症与冠心病

同型半胱氨酸是蛋氨酸和半胱氨酸代谢过程中一个重要的中间产物。研究发现血液中同型半胱氨酸增高，即高同型半胱氨酸血症，能够导致血管内皮损害，促进低密度脂蛋白的氧化、血小板集聚及血管平滑肌细胞增殖，从而促发动脉粥样硬化的发生。人们已经逐渐认识到它是引起心脑血管意外的独立危险因素。近年来，高同型半胱氨酸血症与冠心病，尤其是急性冠状动脉综合征的研究越来越多，然而，结果并非完全一致。遗传和环境两方面的因素共同决定了血浆同型半胱氨酸的水平，补充B族维生素可以降低血浆同型半胱氨酸的水平。     

同型半胱氨酸与急性冠脉综合征

同型半胱氨酸是蛋氨酸代谢过程中的一个中间产物,研究证实,同型半胱氨酸的代谢异常导致的高同型半胱氨酸血症是急性冠脉综合征的独立危险因子.迄今为止,高同型半胱氨酸在急性冠脉综合征发病中的确切作用机制尚不清楚,目前主要认为与氧化机制造成血管内皮损伤和功能失调、破坏体内凝血系统、刺激血管平滑肌增殖、影响脂质代谢和炎性因子等方面有关.     

同型半胱氨酸对球囊损伤大鼠颈动脉原癌基因表达及新生内膜增生的影响

目的观察高蛋氨酸饮食诱导的高同型半胱氨酸(Hcy)血症对大鼠颈动脉球囊损伤后血管组织原癌基因c-fos及c-jun mRNA表达及新生内膜增生的影响,探讨Hcy在血管球囊损伤后新生内膜过度增生中的作用及可能机制.方法采用RT-PCR方法检测血管组织c-fos及c-jun mRNA表达情况,并做半定量分析.采用光镜和计算机图像分析定量方法观察高Hcy血症对大鼠颈动脉内皮损伤后新生内膜增生的影响.结果低蛋氨酸组和高蛋氨酸组c-fos及c-jun mRNA的表达[分别为(1.40±0.21)、(1.43±0.25)及(1.68±0.27)、(1.71±0.30)]均高于对照组[分别为(1.10±0.15)、(1.00±0.13),P<0.05和0.01)],高蛋氨酸组也明显高于低蛋氨酸组(P<0.05).与对照组比较,低蛋氨酸组、高蛋氨酸组的新生内膜增生明显,计算机图像定量分析表明血管损伤后14 d,低和高蛋氨酸组新生内膜增生面积和内∕中膜面积比率比对照组分别增加87%、98%和97%、109%(均为P<0.01), 管腔面积在低、高蛋氨酸组比对照组分别减少45%、55%(P<0.05).结论 (1)高Hcy血症能使球囊损伤后颈动脉新生内膜增生恶化,预示高Hcy血症可能是血管内皮球囊损伤后再狭窄的一个独立危险因素;(2)Hcy能上调血管内皮损伤后动脉组织原癌基因c-fos及c-jun mRNA的表达,且呈浓度依赖性,这可能是其促使血管内皮损伤后新生内膜过度增生的机制之一.     

高同型半胱氨酸血症:心脑血管疾病的独立危险因子

同型半胱氨酸是蛋氨酸和半胱氨酸代谢过程中一个重要的中间产物。由同型半胱氨酸的代谢异常导致的高同型半胱氨酸血症已被许多研究证实是心脑血管疾病发病的独立危险因子,其致病机理尚不十分明确,可能与氧化机制造成的内皮损伤和功能失调,破坏体内凝血纤溶平衡,刺激血管平滑肌细胞增殖和影响脂质代谢等方面有关。     

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.     

Liposomal Hsp90 cDNA induces neovascularization via nitric oxide in chronic ischemia

OBJECTIVE: Induction of angiogenesis has been reported subsequent to eNOS overexpression or activation, the latter involving Hsp90 as a chaperone protein. Here, we investigated the potential of regional Hsp90 overexpression to induce therapeutic neovascularization in vivo in a chronic rabbit hindlimb ischemia model. METHODS: In rabbits (n=7 per group), the external femoral artery was excised at day 0 (d0). At d7, liposomes containing eGFP (control group) or Hsp90 were retroinfused into the anterior tibial vein. At day 7 and day 35, angiographies were obtained and analyzed for collateral formation and perfusion velocity (frame count score) (% of d7 values). Capillary/muscle fiber (C/MF) ratio was calculated from five muscle areas of the ischemic limb. L-NAME and Geldanamycin were co-applied, where indicated. RESULTS: Compared to mock-treated controls, Hsp90 transfected increased C/MF ratio at day 35 (1.78+/-0.15 vs. 1.19+/-0.13, p<0.05), an effect blunted by L-NAME (1.39+/-0.11). Hsp90 transfection increased collateral formation (157+/-11% vs. 110+/-13%) and frame count score (174+/-18% vs. 117+/-10%), both sensitive to inhibition by L-NAME coapplication (135+/-17% and 134+/-14%, respectively). Of note, C/MF ratio was found elevated 3 days after Hsp90 transfection (1.61+/-0.16 at d10), at a time point when collateral formation was unchanged (106+/-6%), and tended to remain elevated in the presence of L-NAME applied thereafter (1.64+/-0.35 at d35), though L-NAME blocked subsequent changes in collateral growth or increase in perfusion at d35. CONCLUSIONS: We conclude that Hsp90 is capable of inducing angiogenesis and arteriogenesis via nitric oxide (NO) in a rabbit model of chronic ischemia. Our findings describe the capillary level as an initial site of Hsp90-cDNA-induced neovascularization, followed by growth of larger conductance vessels, resulting in an improved hindlimb perfusion.     

Niacin improves ischemia-induced neovascularization in diabetic mice by enhancement of endothelial progenitor cell functions independent of changes in plasma lipids

Niacin was shown to inhibit acute vascular inflammation and improves endothelial dysfunction independent of changes in plasma lipids. Here, we investigated whether niacin can increase blood flow recovery after tissue ischemia by enhancing endothelial progenitor cell (EPC) functions in diabetic mice. Starting at 4?weeks after the onset of diabetes, vehicle or niacin (40?mg/kg/day) was administered daily by gavage to streptozotocin (STZ)-induced diabetic mice and diabetic endothelial nitric oxide synthase (eNOS)-deficient mice. Unilateral hindlimb ischemia surgery was conducted after 2?weeks of vehicle or niacin treatment. Compared to the control group, the niacin group had significantly increased ischemic/non-ischemic limb blood perfusion ratio and higher capillary density. These effects were markedly reduced in STZ-induced diabetic eNOS-deficient mice. Flow cytometry analysis showed impaired EPC-like cell (Sca-1(+)/Flk-1(+)) mobilization after ischemia surgery in diabetic mice but augmented mobilization in the mice treated with niacin. Diabetes was induced by administering STZ to FVB mice that received eGFP mouse bone marrow cells to evaluate effects of niacin on bone marrow-derived EPC homing and differentiation to endothelial cells. Differentiation of bone marrow-derived EPCs to endothelial cells in the ischemic tissue around vessels in diabetic mice that received niacin treatment, was significantly increased than that in control group. By in vitro studies, incubation with niacin in high-glucose medium reduced H(2)O(2) production, cell apoptosis, and improved high glucose-suppressed EPC functions by nitric oxide-related mechanisms. Our findings demonstrate that niacin increases blood flow recovery after tissue ischemia in diabetic mice through enhancing EPC mobilization and functions via nitric oxide-related pathways.     

Hyperhomocyst(e)inemia impairs angiogenesis in a murine model of limb ischemia

Hyperhomocyst(e)inemia (HH) is an established independent risk factor for coronary, cerebral and peripheral vascular diseases. Recent studies have indicated that certain cardiovascular risk factors, including diabetes and hypercholesterolemia, impair expression of vascular endothelial growth factor (VEGF) and endogenous angiogenesis. In this study, we investigate the impact of moderate HH on angiogenesis and VEGF pathway in a mouse model of hindlimb ischemia. Upon induction of unilateral hindlimb ischemia, endogenous angiogenesis, expression of VEGF, and phosphorylation of the VEGF receptor Flk-1 were evaluated in mice heterozygous for a deletion of the cystathionine beta-synthase gene (CBS) and compared with those observed in CBS+/+ mice. CBS+/- mice exhibit moderate HH, as demonstrated by measuring plasma total homocyst(e)ine (tHcy) levels, which were significantly higher in these animals compared with CBS+/+ mice (4.77 +/- 0.82 vs 2.10 +/- 0.28, p < 0.01). Twenty-eight days after induction of ischemia, hindlimb blood flow was significantly reduced in CBS+/- mice compared with CBS+/+ animals (0.49 +/- 0.03, n = 12 vs 0.71 +/- 0.09, n = 10; p < 0.05). In addition, there was a significant negative correlation between plasma homocyst(e)ine levels and the laser Doppler perfusion ratio in CBS+/- mice (p = 0.0087, r = -0.7171). While VEGF expression and Flk-1 phosphorylation were not impaired in the ischemic muscles of CBS+/- mice, phosphorylation of the endothelial cell survival factor Akt was significantly inhibited by homocyst(e)ine in a dose-dependent manner in human umbilical vein endothelial cell (HUVECs) in vitro. In conclusion, our findings demonstrate that endogenous angiogenesis is inversely related to plasma levels of homocyst(e)ine in genetically engineered, heterozygous mice with moderate HH. This impairment, however, is not dependent on reduced expression of VEGF or impaired phosphorylation of its receptor Flk-1. In contrast, our data suggest that impaired Akt phosphorylation mediates the impairment of angiogenesis associated with HH.     

肌肉电转促血管形成素-1基因治疗大鼠下肢血管闭塞病

目的观察肌肉电转促血管形成素-1（angiopoietin-1,Ang-1）基因对大鼠下肢血管闭塞病的治疗效果。方法制作大鼠下肢血管闭塞病模型,通过电转Ang-1进行基因治疗,以RT-PCR及免疫组化方法观察Ang-1基因的表达,应用微血管计数、血管造影技术及相关临床指标观察Ang-1基因导入大鼠体内的生物学效应。结果（1）肌肉电转pcD2Ang-1基因可在大鼠局部转基因肌肉组织高效表达Ang-1;（2）转pcD2Ang-1基因组大鼠下肢肌肉组织新生血管及侧支循环数目明显多于同期空载质粒对照组。结论转Ang-1基因可促进大鼠局部组织新生血管形成和侧支循环建立,恢复闭塞部位血供,从而有效治疗血管闭塞病。     

Antiangiogenic effect of angiotensin II type 2 receptor in ischemia-induced angiogenesis in mice hindlimb

This study examined the potential role of angiotensin type 2 (AT(2)) receptor on angiogenesis in a model of surgically induced hindlimb ischemia. Ischemia was produced by femoral artery ligature in both wild-type and AT(2) gene-deleted mice (Agtr2(-)/Y). After 28 days, angiogenesis was quantitated by microangiography, capillary density measurement, and laser Doppler perfusion imaging. Protein levels of vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), Bax, and Bcl-2 were determined by Western blot analysis in hindlimbs. The AT(2) mRNA level (assessed by semiquantitative RT-PCR) was increased in the ischemic hindlimb of wild-type mice. Angiographic vessel density and laser Doppler perfusion data showed significant improvement in ischemic/nonischemic leg ratio, 1.9- and 1.7-fold, respectively, in Agtr2(-)/Y mice compared with controls. In ischemic leg of Agtr2(-)/Y mice, revascularization was associated with an increase in the antiapoptotic protein content, Bcl-2 (211% of basal), and a decrease (60% of basal) in the number of cell death, determined by TUNEL method. Angiotensin II treatment (0.3 mg/kg per day) raised angiogenic score, blood perfusion, and both VEGF and eNOS protein content in ischemic leg of wild-type control but did not modulate the enhanced angiogenic response observed in untreated Agtr2(-)/Y mice. Finally, immunohistochemistry analysis revealed that VEGF was mainly localized to myocyte, whereas eNOS-positive staining was mainly observed in the capillary of ischemic leg of both wild-type and AT(2)-deficient mice. This study demonstrates for the first time that the AT(2) receptor subtype may negatively modulate ischemia-induced angiogenesis through an activation of the apoptotic process.     

Vascular endothelial growth factor-A specifies formation of native collaterals and regulates collateral growth in ischemia

The density of native (preexisting) collaterals and their capacity to enlarge into large conduit arteries in ischemia (arteriogenesis) are major determinants of the severity of tissue injury in occlusive disease. Mechanisms directing arteriogenesis remain unclear. Moreover, nothing is known about how native collaterals form in healthy tissue. Evidence suggests vascular endothelial growth factor (VEGF), which is important in embryonic vascular patterning and ischemic angiogenesis, may contribute to native collateral formation and arteriogenesis. Therefore, we examined mice heterozygous for VEGF receptor-1 (VEGFR-1(+/-)), VEGF receptor-2 (VEGFR-2(+/-)), and overexpressing (VEGF(hi/+)) and underexpressing VEGF-A (VEGF(lo/+)). Recovery from hindlimb ischemia was followed for 21 days after femoral artery ligation. All statements below are P<0.05. Compared to wild-type mice, VEGFR-2(+/-) showed similar: ischemic scores, recovery of hindlimb perfusion, pericollateral leukocytes, collateral enlargement, and angiogenesis. In contrast, VEGFR-1(+/-) showed impaired: perfusion recovery, pericollateral leukocytes, collateral enlargement, worse ischemic scores, and comparable angiogenesis. Compared to wild-type mice, VEGF(lo/+) had 2-fold lower perfusion immediately after ligation (suggesting fewer native collaterals which was confirmed by angiography) and blunted recovery of perfusion. VEGF(hi/+) mice had 3-fold greater perfusion immediately after ligation, more native collaterals, and improved recovery of perfusion. These differences were confirmed in the cerebral pial cortical circulation where, compared to VEGF(hi/+) mice, VEGF(lo/+) formed fewer collaterals during the perinatal period when adult density was established, and had 2-fold larger infarctions after middle cerebral artery ligation. Our findings indicate VEGF and VEGFR-1 are determinants of arteriogenesis. Moreover, we describe the first signaling molecule, VEGF-A, that specifies formation of native collaterals in healthy tissues.     

Repeated thermal therapy up-regulates endothelial nitric oxide synthase and augments angiogenesis in a mouse model of hindlimb ischemia.

BACKGROUND: Nitric oxide (NO), constitutively produced by endothelial NO synthase (eNOS), plays roles in angiogenesis. Having reported that thermal therapy up-regulated the expression of arterial eNOS in hamsters, we investigated whether this therapy increased angiogenesis in mice with hindlimb ischemia. METHODS AND RESULTS: Unilateral hindlimb ischemia was induced in apolipoprotein E-deficient mice, which were divided into control and thermal therapy groups. The latter mice were placed in a far-infrared dry sauna at 41 degrees C for 15 min and then at 34 degrees C for 20 min once daily for 5 weeks. Laser Doppler perfusion imaging demonstrated that the ischemic limb/normal side blood perfusion ratio in the thermal therapy group was significantly increased beyond that in controls (0.79+/-0.04 vs 0.54+/-0.08, p<0.001). Significantly greater capillary density was seen in thermal therapy group (757+/-123 /mm2 vs 416+/-20 /mm2, p<0.01). Western blotting showed thermal therapy markedly increased hindlimb eNOS expression. To study possible involvement of eNOS in thermally induced angiogenesis, thermal therapy was given to mice with hindlimb ischemia with or without N(G)-nitro-L-arginine methyl ester (L-NAME) administration for 5 weeks. L-NAME treatment eliminated angiogenesis induced using thermal therapy. Thermal therapy did not increase angiogenesis in eNOS-deficient mice. CONCLUSION: Angiogenesis was induced via eNOS using thermal therapy in mice with hindlimb ischemia.     

A novel ultrasound method for evaluation of collateral development in limb ischemia

Although clinical studies are underway to evaluate the effectiveness of angiogenesis, there are no validated, non-invasive methods to assess peripheral collateral development. This study was performed to validate a novel ultrasound-based method of assessing collateral formation in a pig model of hindlimb ischemia. Ultrasonography of predefined ultrasound planes was performed on 12 pigs immediately after ligation of the right common femoral artery, and 7, 14, 28 and 42 days thereafter. A custom software program was used to evaluate both color Doppler (CD) and power Doppler (PD) images to generate flow indices. Collateral development was observed with ultrasound as early as 7 days post-arteriectomy and increased dramatically by 28 days. Areas of persistent ischemia resulting from inadequate collateral formation were easily quantified in all images. Collaterals detected on ultrasound were confirmed by angiography and histology, and tissue perfusion by a fluorescent microsphere method. As demonstrated with color and power Doppler measurements, collateral formation is initiated early after ischemic injury in this large juvenile animal model of angiogenesis. This non-invasive method is useful to quantify blood flow, visualize angiogenesis and determine areas of persistent lower limb ischemia, and may have an important role in evaluating new approaches to modulate angiogenesis.     

Combined treatment of sustained-release basic fibroblast growth factor and sarpogrelate enhances collateral blood flow effectively in rabbit hindlimb ischemia.

BACKGROUND: The effectiveness of sustained-release basic fibroblast growth factor (bFGF) in potentiating arteriogenesis and angiogenesis was evaluated, as well as determining whether chronic oral administration of sarpogrelate, a serotonin blocker, would further increase collateral blood flow in the rabbit hindlimb following surgical induction of ischemia by femoral artery extraction. METHODS AND RESULTS: Two weeks after femoral artery removal, the rabbits were assigned to 1 of 4 experimental groups and treated for 4 weeks: group A, no treatment; group B, supplemented with diet containing sarpogrelate; group C, single intramuscular injection of sustained-release form of bFGF microspheres; group D: combined treatment with sustained-release bFGF and sarpogrelate. Endpoint measurements performed at 6 weeks found that the ischemic hindlimb blood flow was significantly improved in the rabbits that received sustained-release bFGF, with a further significant improvement in those with the additional administration of sarpogrelate. Angiographic assessment revealed augmented density of collateral vessels in the medial thigh region in the rabbits given the combined treatment. CONCLUSIONS: The findings demonstrate that sustained-release bFGF stimulated the development of collateral vessels, and additional administration of sarpogrelate produced a further improvement in hindlimb blood flow in the rabbit hindlimb ischemia model.