caveolin-1表达在糖尿病大鼠下肢缺血中的作用及其与eNOS/NO通路的关系

背景与目的：研究表明caveolin-1可促进血管新生,并与糖尿病病理过程密切相关。本研究推测caveolin-1可能在糖尿病下肢缺血中发挥作用,并在糖尿病大鼠急性下肢缺血模型实验中探讨其作用及机制。 方法：选用80只健康雄性SD大鼠,应用STZ法构建1型糖尿病大鼠模型,取建模成功的大鼠随机分为4组,分别行单纯股动脉游离（假手术组）、股动脉及分支离断（模型组）、股动脉及分支离断+尾静脉注射含caveolin-1的质粒（转染组）、股动脉及分支离断+尾静脉注射不含caveolin-1质粒脂质体溶液（空转组）。于术后14 d取各组大鼠腓肠肌组织标本,HE染色观察组织形态及炎性细胞浸润情况;ELISA法检测组织中NO水平;免疫组织化学染色检测组织中caveolin-1、eNOS和CD34标记的微血管密度（MVD）。 结果：与假手术组比较,模型组及空转组的腓肠肌组织萎缩明显,组织中有较多的炎症细胞浸润,转染组肌肉萎缩不明显,炎症细胞浸润较少;模型组和空转组的腓肠肌组织中NO表达明显降低,转染组NO表达明显增加（均P<0.01）;模型组、空转组、转染组caveolin-1表达均明显升高,转染组升高更为明显（均P<0.01）;模型组和空转组eNOS表达无明显变化（均P>0.05）,转染组eNOS表达明显升高（P<0.01）;模型组、空转组、转染组MVD均有增加,转染组升高更为明显（均P<0.01）;以上指标在模型组与空转组间的差异均无统计学意义（均P>0.05）。 结论：caveolin-1高表达对糖尿病下肢缺血有明显改善作用,其机制可能是通过活化eNOS/NO通路,从而促进NO生成有关。     

红细胞生成素对慢性肾衰竭大鼠肾小球内皮细胞功能的影响

目的 探讨红细胞生成素（EPO）对慢性肾衰竭（CRF）大鼠肾小球内皮细胞功能的影响。 方法 采用分阶段5/6肾切除术制备大鼠慢性肾衰竭动物模型。实验动物按数字随机法分为4组：假手术组（对照组）、慢性肾衰竭组（模型组）及EPO干预的两个剂量组（小剂量组EPO用量30 U/kg,大剂量组EPO用量50 U/kg）。慢性肾衰竭大鼠皮下注射EPO 6周后处死。检测各组大鼠血肌酐（Scr）、血尿素氮（BUN）、尿蛋白、血红蛋白（Hb）和血压的变化,并观察肾组织病理改变。免疫组化法检测肾小球CD34、CD31表达;RT-PCR检测肾组织内皮素1（ET-1）、内皮细胞一氧化氮合酶（eNOS）和血管内皮细胞生长因子（VEGF） mRNA的表达。 结果 与模型组比较,EPO治疗能显著增加大鼠肾小球CD34、CD31的表达（均P < 0.05）;下调肾组织ET-1 mRNA的表达（P < 0.05）;上调肾组织eNOS和 VEGF mRNA的表达（均P < 0.05）。此外,EPO治疗还能使大鼠Scr、BUN、尿蛋白和血压水平显著降低（均P < 0.05）,Hb水平显著增高（P < 0.05）,肾组织病理损害明显减轻。 结论 EPO能减轻慢性肾衰竭大鼠肾脏的病理损害,改善肾功能。这种作用可能与其促进肾小球内皮细胞的修复和改善内皮功能有关。     

重组人内皮抑素对尿毒症腹膜透析大鼠腹膜新生血管形成的影响

目的 研究重组人内皮抑素对尿毒症腹膜透析（PD）大鼠腹膜新生血管形成的影响。 方法 40只雄性SD大鼠,按随机数字表法分为正常对照组、肾衰竭非透析组、4.25%PD组、重组人内皮抑素10 mg/kg PD组、重组人内皮抑素40 mg/kg PD组,每组8只。对PD组规律PD 28 d。重组人内皮抑素干预组在行规律PD期间,隔天1次皮下注射重组人内皮抑素,至透析第28天结束。28 d后取各组大鼠新鲜腹膜组织,RT-PCR法检测腹膜组织血管内皮生长因子（VEGF）、碱性成纤维细胞生长因子（bFGF） mRNA表达;免疫组化染色检测VEGF、bFGF蛋白表达。CD34染色观察腹膜组织毛细血管密度（MVD）。 结果 各组大鼠腹膜组织均表达VEGF和bFGF,肾衰竭非透析组、4.25%PD组VEGF及bFGF mRNA、蛋白表达均显著高于正常对照组（均P < 0.05）;重组人内皮抑素10 mg/kg PD组、40 mg/kg PD组VEGF及bFGF mRNA、蛋白表达均显著低于4.25%PD组（均P < 0.05）。肾衰竭非透析组、4.25%PD组腹膜组织MVD均显著高于正常对照组（均P < 0.05）;重组人内皮抑素10 mg/kg、40 mg/kg PD组腹膜组织MVD均显著低于正常对照组（均P < 0.05）。 结论 重组人内皮抑素可以有效抑制PD大鼠腹膜新生血管的形成,下调VEGF、bFGF mRNA及蛋白表达可能是其抑制腹膜新生血管形成的机制之一。     

2型糖尿病大鼠后肢缺血模型的建立及评价

目的建立2型糖尿病大鼠后肢缺血模型并进行评价,为后续的干预实验提供研究平台。方法将15只SD大鼠随机分为正常对照组、糖尿病组及糖尿病后肢缺血组,每组5只。糖尿病组及糖尿病后肢缺血组的10只大鼠均给予高脂饮食喂养4周后,腹腔注射链脲佐菌素（STZ,40mg／kg）以建立2型糖尿病模型。糖尿病后肢缺血组大鼠建模成功后行双侧髂总动脉结扎术以建立后肢缺血模型,正常对照组和糖尿病组大鼠仅分离髂总动脉,不予结扎。2周后对3组大鼠股动脉的起始段行彩色多普勒超声检查,以检测股动脉的血流峰值速度和血流加速时间;取缺血部位的小腿三头肌及大腿股四头肌组织,分别行HE染色及免疫组化SP染色,以观察3组大鼠肌细胞的营养状况及血管再生情况。结果后肢缺血模型建模2周后,正常对照组、糖尿病组和糖尿病后肢缺血组大鼠的血流峰值速度分别为（22．49±3．02）cm／s、（17．36±2．60）cm／s和（11．23±1．26）cm／s,血流加速时间分别为（0．080±0．009）S、（0．120±0．009）S和（0．160±0．020）s,糖尿病后肢缺血组大鼠的股动脉血流峰值速度小于正常对照组和糖尿病组（P〈0．05）,而血流加速时间较长（P〈0．05）。HE染色结果显示：糖尿病后肢缺血组大鼠小腿三头肌的结构破坏,有大量炎症细胞浸润,肌肉损伤程度重于正常对照组和糖尿病组。免疫组化sP染色结果显示：糖尿病后肢缺血组大鼠大腿股四头肌的毛细血管密度[（1．40±0．55）个／HPF]小于正常对照组[（6．80±0．84）个／HPF]及糖尿病组[（4．60±0．55）个／HPF],差异均有统计学意义伊〈O．05）。结论对SD大鼠给予高脂饮食联合小剂量STZ注射可以成功诱导2型糖尿病模型,在此模型基础上结扎髂总动脉可以成功制备糖尿病后肢缺血模型。     

骨髓间充质干细胞治疗慢性后肢缺血机理的初步研究

目的利用细胞示踪技术探讨骨髓间充质干细胞（MSCs）治疗慢性后肢缺血的相关机理。方法采用密度梯度离心法结合直接贴壁法分离和培养大鼠MSCs,并以5-溴脱氧尿嘧啶核苷（BrdU）标记。采用线栓法制备8只Lewis大鼠慢性后肢缺血模型,将其随机均分为MSCs移植组和对照组,分别于患侧后肢肌肉注射MSCs和生理盐水。分别于移植术后第7天和第14天,对其进行临床观察、后肢血流量测定及后肢血管造影,再于相应时间点处死大鼠,取患侧后肢股四头肌和腓肠肌,行HE染色及BrdU免疫组化染色。结果移植术后14 d,8只大鼠全部成活,移植部位均无坏死和肿瘤形成;MSCs移植组大鼠患侧/健侧后肢的血流灌注比值明显增高（1.773比1.279）,而血管造影结果提示2组大鼠的侧支血管数量比值未见显著增加（0.908比0.835）。HE染色结果示2组大鼠的股四头肌及腓肠肌并未发生特殊的病理学变化。BrdU免疫组化结果显示,阳性颗粒定位为股四头肌及腓肠肌的间质细胞和血管内皮细胞;且MSCs的分布存在差异,移植术后7 d腓肠肌内阳性细胞所占比例明显高于股四头肌,而14 d时则相反。结论 MSCs移植在术后早期可以提高血流灌注量,但这并非为增加了侧支血管数量使然,MSCs移植后所引起的旁分泌效应可能在术后早期起着重要的作用。     

负压吸引对糖尿病性ED大鼠阴茎海绵体组织一氧化氮合酶表达的影响

目的研究负压吸引对糖尿病性勃起功能障碍（ED）大鼠阴茎组织一氧化氮合酶（NOS）表达水平的影响。方法25只实验鼠中随机选取5只为正常对照组（A组）,其余火鼠用链脲左菌素和阿朴吗啡诱导建立Ⅰ型糖尿病性ED大鼠模型。之后把造模成功的糖尿病性ED大鼠随机分成糖尿病ED吸引组（B组）和糖尿病ED非吸引组（C组）。在B组大鼠负压吸引治疗结束后将A、B、C3组大鼠处死并取阴茎组织进行石蜡包埋。采用免疫组织化学方法检测各组大鼠阴茎组织中三种一氧化氮合酶亚型（nNOS、eNOS、iNOS）的表达情况。结果A组大鼠阴茎组织中nNOS蛋白表达水平高于B组和C组（均P〈0.001）;A组和B组大鼠阴茎组织中eNOS蛋白表达水平高于C组（均P〈0.01）;A组iNOS蛋白表达水平低于B组和C组（P〈0.01,P〈0.001）,同时B组iNOS蛋白表达水平低于C组（P〈0.01）;剩余其他各组间的比较差异无统计学意义（P〉0.05）。结论负压吸引可以通过升高阴茎组织中的eNOS和降低iNOS的表达来改善勃起功能。     

下肢静脉高压大鼠后肢皮肤病变的组织学研究

目的探讨下肢静脉高压大鼠皮肤病变的生物分子学机制。方法通过建立合适的下肢静脉高压大鼠模型来观察大鼠后肢病变组织的组织学改变。将36只大鼠随机分成4组,A组为下肢静脉高压+舒洛地特组,B组为下肢静脉高压+生理盐水组,C组为单纯下肢静脉高压组,D组为正常对照组。A、B组分别腹腔注射舒洛地特和生理盐水2周, 1周、2周、2个月后分别检测大鼠后肢组织中血管细胞黏附分子-1(VCAM-1)、细胞间黏附分子-1(ICAM-1)、肿瘤坏死因子-α(TNF-α)和内皮一氧化氮合酶(eNOS)表达情况。结果免疫组化结果显示B、C组VCAM-1、ICAM-1、TNF-α阳性表达量逐渐增加,eNOS阳性表达量逐渐减低,和正常组比较差异有统计学意义(P0.05),B、C组间差异无统计学意义(P0.05)。A组VCAM-1、ICAM-1、TNF-α阳性表达量逐渐降低,eNOS阳性表达量逐渐增加,和B组间差异有统计学意义(P0.05),2个月时和正常组比较差异无统计学意义(P0.05)。结论下肢静脉高压时存在血管内皮损伤,VCAM-1、ICAM-1、TNF-α表达增加,eNOS表达降低;舒洛地特可以有效改善并修复损伤的血管内皮,调节VCAM-1、ICAM-1、TNF-α、eNOS的表达水平。     

大鼠肢体缺血再灌注早期血栓前状态的研究

目的探讨大鼠急性下肢缺血再灌注早期血栓的形成情况。方法将大鼠随机分为假手术组、下肢缺血再灌注组两组。夹闭大鼠股动脉并用张力带绑扎下肢，建立急性下肢缺血再灌注大鼠模型。观察急性下肢缺血再灌注大鼠血小板膜糖蛋白GPⅡb／Ⅲa和血管内皮细胞血栓调节蛋白（thrombomoclulin，TM）的表达。结果缺血再灌注组大鼠血小板膜糖蛋白GPⅡb／Ⅲa表达高于假手术组（P〈0．05）；缺血再灌注组大鼠血管内皮TM表达低于假手术组（P〈0．05）。结论急性下肢缺血再灌注可能导致大鼠血栓前状态的形成。     

α-硫辛酸通过逆转内皮型一氧化氮合成酶过表达改善糖尿病膀胱功能

目的 明确抗氧化治疗方法 对糖尿病膀胱病变的治疗效果,探讨该方法 的作用机制.方法 制备链脲佐菌素(STZ)-糖尿病大鼠模型;通过尿流动力学检查方法 明确正常对照组、糖尿病组和治疗组的膀胱功能状态,观察α-LA对大鼠排尿功能的治疗效果;应用逆转录-聚合酶链反应(RT-PCR)和Western blot方法 检测α-LA治疗前后各组大鼠膀胱组织中内皮型一氧化氮合成酶(eNOS)及其代谢标志物3-硝基酪氨酸(3-NT)的表达水平.结果 糖尿病大鼠的最大膀胱容量、单次排尿量、残余尿量均呈时间依赖性显著增加(P＜0.01);膀胱排尿率亦显著下降(P＜0.05),经仅α-LA治疗后,上述指标显著改善.α-LA治疗后,糖尿病大鼠膀胱组织中显著增加的eNOS、3-NT表达亦明显下降.结论 α-LA可能通过抑制eNOS过表达减少氧化应激、改善糖尿病膀胱病变.     

大鼠缺血后肢骨骼肌血管内皮生长因子及其受体的表达

目的 研究大鼠缺血后肢侧枝代偿和血管内皮生长因子（VEGF）及其受体表达的动态变化。为外源性VEGF治疗下肢缺血性疾病提供理论依据。方法 切除SD大白鼠右后肢全长股动脉，随机分为9个时间组：造模后1、3d、1、2、3、4、6、8及12周，各组5只动物。分别于造模前后和观察期末检测双后肢大、小腿肌肉Fit-1、Flk-1蛋白及mRNA表达，各组观察期末实验动物后肢动脉DSA检查。结果 （1）缺血后3d，5只大鼠右后肢出现溃疡（11．11％）；2周后，4只大鼠后肢溃疡愈合，而1只趾端坏疽（2．22％）。（2）缺血后2周，患肢侧枝形成达到高峰，12周时仍可见侧支血管显影。（3）缺血早期（3周内），VEGF及其受体的表达均较健侧显著增强（P〈0．05）；缺血中期（3～8周）。VEGF和Flt-1表达迅速下降，Flk-1仍表达；缺血后期（8周后），VEGF及其受体的表达均低至极低水平，与对侧差异无统计学意义（P〉0．05）。结论（1）肢体缺血后自身的血管新生不能完全满足缺血组织的需要。（2）缺血早期外源性的VEGF补充是不必要的；缺血中期补充VEGF是适宜的；缺血后期在应用VEGF治疗的同时，也需要干预受体的表达。     

Overexpression of endothelial nitric oxide synthase increases skeletal muscle blood flow and oxygenation in severe rat hind limb ischemia

OBJECTIVE: Although nitric oxide (NO) has a critical role in angiogenesis, the therapeutic potential of NO synthase overexpression in severe ischemia remains undefined. We tested the hypothesis that overexpression of endothelial NO synthase (eNOS) would improve tissue perfusion in severe hind limb ischemia. METHODS: Severe hind limb ischemia was induced in 122 adult male Sprague-Dawley rats. Ten days after the induction of hind limb ischemia, vascular isolation and intraarterial delivery of an adenoviral vector encoding eNOS (AdeNOS), a control adenoviral vector (AdE1), or phosphate-buffered saline solution (PBS) was performed. Skeletal muscle blood flow, muscle oxygen tension, angiography, and immunohistochemistry for capillary counts were measured. RESULTS: Gene transfer of AdeNOS increased eNOS protein expression and enzyme activity. Two weeks after gene transfer, skeletal muscle blood flow was fourfold higher in eNOS-transduced than in AdE1-transduced or PBS treated rats and was similar to exercise-induced maximal flow in nonischemic muscle. eNOS overexpression increased muscle oxygen tension in a titer-dependent fashion. This increase persisted 1 month after transduction, even though eNOS enzyme activity had declined to normal levels. Angiography and capillary counts showed that eNOS overexpression increased the size and number of collateral arteries, but did not significantly increase the capillary-muscle fiber ratio. CONCLUSIONS: eNOS overexpression in an ischemic rat hind limb significantly increased skeletal muscle blood flow, muscle oxygen tension, and collateral arteries (arteriogenesis). Furthermore, eNOS overexpression did not result in capillary angiogenesis above control levels. These studies demonstrate the potential for eNOS overexpression as treatment for severe limb ischemia in human beings.     

Nitrite Anion Therapy Protects Against Chronic Ischemic Tissue Injury in db/db Diabetic Mice in a NO/VEGF-Dependent Manner

Nitrite anion has been demonstrated to be a prodrug of nitric oxide (NO) with positive effects on tissue ischemia/reperfusion injury, cytoprotection, and vasodilation. However, effects of nitrite anion therapy for ischemic tissue vascular remodeling during diabetes remain unknown. We examined whether sodium nitrite therapy altered ischemic revascularization in BKS-Lepr^db/db mice subjected to permanent unilateral femoral artery ligation. Sodium nitrite therapy completely restored ischemic hind limb blood flow compared with nitrate or PBS therapy. Importantly, delayed nitrite therapy 5 days after ischemia restored ischemic limb blood flow in aged diabetic mice. Restoration of blood flow was associated with increases in ischemic tissue angiogenesis activity and cell proliferation. Moreover, nitrite but not nitrate therapy significantly prevented ischemia-mediated tissue necrosis in aged mice. Nitrite therapy significantly increased ischemic tissue vascular endothelial growth factor (VEGF) protein expression that was essential for nitrite-mediated reperfusion of ischemic hind limbs. Nitrite significantly increased ischemic tissue NO bioavailability along with concomitant reduction of superoxide formation. Lastly, nitrite treatment also significantly stimulated hypoxic endothelial cell proliferation and migration in the presence of high glucose in an NO/VEGF-dependent manner. These results demonstrate that nitrite therapy effectively stimulates ischemic tissue vascular remodeling in the setting of metabolic dysfunction that may be clinically useful.     

骨髓间充质干细胞联合血管内皮生长因子基因治疗肢体缺血的实验研究

目的 观察骨髓间充质干细胞(bone mesenchymal stem cell,BMSC)联合血管内皮生长因子(vascular endothelial growth factor,VEGF)基因治疗对家兔肢体缺血模型的疗效.方法 切除新西兰兔右后肢全长股浅动脉并结扎股深动脉以建立兔后肢缺血模型,随机分为空质粒对照组(EP组)、骨髓间充质干细胞组(BMSC组)、VEGF基因治疗组(VEGF组)及联合治疗组(BV组),每组各8只.分别于治疗后28 d及30 d进行动脉造影及VEGF免疫组化染色.结果 EP组、BMSC组及VEGF组的新生血管计数组间比较差异无统计学意义(P＞0.05).BV组的新生血管计数较其余3组明显增加,差异有统计学意义(F=35.47,P＜O.01).BMSC组及VEGF组的VEGF免疫组化染色呈阳性表达,与EP组比较差异有统计学意义(F=764.32,P＜0.01).BV组的VEGF免疫组化染色呈强阳性表达,与其余3组比较差异有统计学意义(F =764.32,P＜0.01).结论 BMSC联合VEGF基因治疗兔肢体缺血可使VEGF获得稳定而有效的表达,从而改善肢体缺血.     

非胰岛素依赖型糖尿病小鼠对缺血刺激的反应及其机制研究

目的研究在非胰岛素依赖型糖尿病状态下,小鼠肢体对缺血刺激的血管生成反应,并探讨其发生机制。方法雄性C57BL／6小鼠40只,分别以常规饲料（对照组20只）和高脂肪饲料（糖尿病组20只）喂养。12周后,创建小鼠下肢动脉缺血模型,应用激光多普勒扫描仪记录肢体血流恢复情况。术后4周处死小鼠,取下肢肌肉组织行组织病理学检查,CD31染色,评价血管密度;取正常下肢肌肉组织分别行ELISA和Western Blot检测血管内皮生长因子（VEGF）及其下游因子AKT的表达状况,行逆转录聚合酶链反应检测VEGF受体的表达情况。结果非胰岛素依赖型糖尿病鼠肢体缺血后其自身恢复和新生血管密度明显低于正常对照组小鼠;肌肉组织中VEGF浓度明显高于对照组,而VEGF受体表达差异却无统计学意义。肌肉组织中PAKT／AKT比值明显低于对照组。结论非胰岛素依赖型糖尿病肢体对缺血刺激的反应明显减弱,这一现象可能与VEGF信号传导通路功能不全有关。     

乌司他丁联合CRRT对重症急性胰腺炎患者血管内皮功能和血小板活化因子的影响

目的 探讨乌司他丁联合连续肾脏替代治疗（CRRT）对重症急性胰腺炎（SAP）患者血管内皮功能和血小板活化因子的影响。方法 选择西安交通大学第二附属医院2016年1月至2019年12月收治的60例SAP患者,采用随机数字表法随机分为对照组和干预组,每组30例。对照组行常规治疗,干预组在此基础上给予乌司他丁联合CRRT治疗。比较两组患者治疗前及干预7 d后血管内皮功能指标[内皮素-1（ET-1）、一氧化氮（NO）、血管性假血友病因子相关抗原（vWF:Ag）、血管内皮生长因子（VEGF）]和血小板活化因子[血小板α颗粒膜蛋白（GMP-140）、血栓烷B₂（TXB₂）],并比较两组治疗前后APACHE II、Balthazar CT评分情况。结果 两组患者治疗前血清ET-1、NO、vWF:Ag、VEGF等血管内皮功能指标无统计学差异（P＞0.05）;治疗后,两组患者血清ET-1、vWF:Ag水平均较治疗前明显降低（P＜0.05）,NO、VEGF水平均较治疗前明显升高（P＜0.05）,且干预组患者ET-1、NO、vWF:Ag的改变程度均大于对照组,差异均有统计学意义（P＜0.05）,但干预组患者VEGF的改变程度小于对照组,差异有统计学意义（P＜0.05）。两组患者治疗前血清GMP-140、TXB₂等血小板活化因子水平无统计学差异（P＞0.05）;治疗后,两组患者上述指标水平均较治疗前明显降低（P＜0.05）,且干预组患者上述指标下降程度均大于对照组,差异均有统计学意义（P＜0.05）。两组患者治疗前APACHE II、Balthazar CT评分比较无统计学差异（P＞0.05）;治疗后,两组患者上述评分均较治疗前明显降低（P＜0.05）,且干预组患者上述评分的降低程度均大于对照组,差异均有统计学意义（P＜0.05）。Spearman分析发现,Balthazar CT评分与ET-1、vWF:Ag、GMP-140、TXB₂呈正相关,与NO呈负相关。结论 血管内皮功能及血小板活化情况改善可能是乌司他丁联合CRRT治疗SAP有效的作用机制之一。     

Analysis of the Correlation of Plasma NO and ET-1 Levels in Rats With Acute Mesenteric Ischemia

Mesenteric ischemia is a devastating disease process that frequently challenges clinicians. To enhance the early diagnosis of gut ischemia and judgment of its severity, it may be helpful to detect the unusual existence or increase in biomarkers in the body fluid. The aim of the present study was to evaluate the correlation of plasma nitric oxide (NO) and endothelin-1 (ET-1) levels to mesenteric ischemia using an animal model. Acute mesenteric ischemia (AMI) was produced experimentally by occlusion of the mesenteric vessels in the terminal ileum by the tenting of a thread. The determination of plasma NO and ET-1 levels were obtained before operation (T0, baseline value), and at 10 (T10), 20 (T20), 30 (T30), and 60 (T60) min after the creation of AMI. Sham-operated rats served as controls. After 30 min of experiments, the plasma NO and ET-1 levels were significantly higher in the AMI group than in the control group (both p <. 01). Both the plasma NO and ET-1 levels in AMI group increased significantly after 30 min of ischemia (both p <. 001 vs. respective baseline value), and they were 60% and 84% above the baseline value, respectively. In addition, ischemic intestinal injury was confirmed by the significantly elevated histological scores in the AMI group after 60 min of ischemia (p <. 001). Our preliminary results suggest the possibility of important insights regarding NO and ET-1 changes into the mechanism of pathogenesis in AMI in rats. The increases in plasma NO and ET-1 levels may potentially be noninvasive biomarkers for the early detection of this disease.     

Analysis of the correlation of plasma NO and ET-1 levels in rats with acute mesenteric ischemia.

Mesenteric ischemia is a devastating disease process that frequently challenges clinicians. To enhance the early diagnosis of gut ischemia and judgment of its severity, it may be helpful to detect the unusual existence or increase in biomarkers in the body fluid. The aim of the present study was to evaluate the correlation of plasma nitric oxide (NO) and endothelin-1 (ET-1) levels to mesenteric ischemia using an animal model. Acute mesenteric ischemia (AMI) was produced experimentally by occlusion of the mesenteric vessels in the terminal ileum by the tenting of a thread. The determination of plasma NO and ET-1 levels were obtained before operation (T0, baseline value), and at 10 (T10), 20 (T20), 30 (T30), and 60 (T60) min after the creation of AMI. Sham-operated rats served as controls. After 30 min of experiments, the plasma NO and ET-1 levels were significantly higher in the AMI group than in the control group (both p < .01). Both the plasma NO and ET-1 levels in AMI group increased significantly after 30 min of ischemia (both p < .001 vs. respective baseline value), and they were 60% and 84% above the baseline value, respectively. In addition, ischemic intestinal injury was confirmed by the significantly elevated histological scores in the AMI group after 60 min of ischemia (p < .001). Our preliminary results suggest the possibility of important insights regarding NO and ET-1 changes into the mechanism of pathogenesis in AMI in rats. The increases in plasma NO and ET-1 levels may potentially be noninvasive biomarkers for the early detection of this disease.     

Regulation of VEGF in Diabetic Patients with Critical Limb Ischemia

Diabetic patients are at a 10- to 20-fold increased risk for the development of critical limb ischemia. Vascular endothelial growth factor (VEGF) is critical for the development of collateral blood vessels, which can effectively bypass peripheral arterial occlusions. We therefore set out to determine if the regulation of VEGF in patients with peripheral vascular disease differs in diabetic and nondiabetic patients. Diabetic and nondiabetic patients with peripheral vascular disease were divided into those with or without critical limb ischemia as defined by clinical criteria (rest pain, nonhealing ulcer). Monocytes from peripheral blood were isolated from all patients and the hypoxic induction of VEGF was determined in vitro. In patients without diabetes, we found that there was no significant difference in the hypoxic induction of VEGF between patients with or without critical limb ischemia. However, in diabetic patients we found that patients with critical limb ischemia produced significantly more VEGF than patients without critical limb ischemia (6.3 +/- 1.3 vs. 2.1 +/- 0.3, p < 0.015). We conclude that diabetic patients with critical limb ischemia do not have an impairment in the ability to produce VEGF with hypoxia. Contrary to current dogma, treatment paradigms directed at increasing VEGF production in the diabetic patient with critical limb ischemia might not be beneficial.