血栓形成后增加内皮功能【精品-ppt】【精品-ppt】

血栓形成后增加内皮功能Vikram S. Kashyap, M.D., F.A.C.S. Associate Professor of Surgery Department of Vascular SurgeryThe Cleveland Clinic,New Horizons in Cardiovascular Treatment (Angiogenesis and other)December 11, 2008,病 例,53 岁、女性、右下肢急性疼痛4天右下肢无波动，股动脉无明显Doppler 信号 (Rutherford 缺血分级 IIA)既往史90年代早期行主动脉重建，2002年右髂动脉植入支架1998年因缺血/感染行左侧髋关节离断术肝素过敏本病例使用比伐卢定抗凝,主动脉造影,左肱动脉途径主动脉造影,使用Angiojet行脉冲式溶栓治疗,20 cm输注导管, tPA at 0.5 mg/hr,每隔12小时行动脉造影, 反复 PMT,10 cm 输注导管, 持续 tPA,本病例技术24小时检查示血栓消退,血栓溶解后暴露病变使用7mm球囊行PTA动脉造影,病变,完成后动脉造影,溶栓治疗的益处,能够显示引起急性闭塞的潜在“病变” 降低再灌注损伤可选择更多治疗手段- 腔内治疗: 血管成形+/- 支架植入- 有限的外科手术 (补片成形,动脉内膜切除)- 在完善检查后行新的旁路手术 (心功能,静脉检查, 等.),尽管初见成效，但有时,尽管初见成效，但有时,临床上急性动脉血栓形成仍然是一个棘手的疾病临床常见血栓切除或溶栓后继发血管痉挛或再发血栓形成近20% 病例发生再发血栓形成 (易于血栓形成内膜表面考虑可引起血小板聚集形成凝血)内皮血栓形成效应还没有完全阐明,血栓-内皮相互作用的临床关联,在成功除去左肱动脉内急性栓子后的动脉造影,血管痉挛= 栓子引起的内皮功能异常?,血管痉挛可通过NO供体来缓解如果有持续血凝块，血管痉挛难以处理在多个动物模型中，血栓形成可引起内皮功能异常NO水平减低可导致内皮功能异常,组织浴槽系统,Reil, et al EJVES 2000,腔内血栓,血栓形成后扫描电镜观察,VIII因子免疫组化,正 常血栓形成后,溶栓试验,*,*,p=0.003,p=0.007,L-精氨酸对EDR和NO的影响,Kashyap et al., JVS 2001,Western Blot,在鼠肾下腹主动脉（IRA），血栓形成对EDR的影响。 对照组EDR（无血栓形成IRA n=5) 与实验组EDR比较（血栓形成后IRA n=4). *P0.05, *P3,精氨酸酶 II,血栓怎样引起内皮功能异常 ?机制,造成内皮细胞的丢失-No清除 NO-Perhaps降低NO的分泌或弥散-No通过影响eNOS减低 NO 的产量 -No通过Y+ 通道影响L-精氨酸运输- No增加内源性血管收缩剂No降低L-精氨酸的可用性Yes 凝血酶增加精氨酸酶活力,L-精氨酸代谢途径,未来研究方向,体外试验 (内皮细胞)凝血酶、纤维蛋白暴露于精氨酸酶阻断剂活化中性粒细胞效应体外试验 (啮齿动物模型)在血栓形成的肾下腹主动脉使用精氨酸酶阻断剂基因敲除鼠模型人体试验人动脉标本内皮细胞功能使用溶栓治疗与L-精氨酸行RCT研究,结 论,暴露于凝血酶的内皮细胞增加了精氨酸酶的活性NO 产生能力不受影响局部使用L-精氨酸和精氨酸酶阻断剂可以调整内皮细胞异常功能目的性增加NO可能是一个有前途的治疗方法,Questions?,Enhancing Endothelial Function After ThrombosisVikram S. Kashyap, M.D., F.A.C.S. Associate Professor of Surgery Department of Vascular SurgeryThe Cleveland Clinic,New Horizons in Cardiovascular Treatment (Angiogenesis and other)December 11, 2008,Case,53 y.o. female with acute R leg pain for 4 days. No R leg pulses, faint femoral Doppler signal (Rutherford Class IIA ischemia)PMHAortic reconstruction in the early 1990s, R iliac stent 2002Previous L hip disarticulation secondary to ischemia/infection in the 1998Heparin allergybivalirudin (Angiomax) used for this case,Aortogram,L brachial approachAortography,Power-pulse thrombolysis with Angiojet,20 cm infusion catheter, tPA at 0.5 mg/hr,Lysis check angiogram at 12 hours, repeat PMT,10 cm infusion catheter, Continue tPA,Technique in this caselysis check 24 hours,Thrombolysis uncovers the culprit lesionPTA with a 7 mm balloonCompletion arteriography,Culprit lesion,Completion arteriogram,Benefits of Thrombolytic Therapy,A “culprit lesion” can be identifiedthe underlying reason for the acute occlusionReperfusion injury may be attenuatedMore options are available- endovascular only: angioplasty+/- stenting- a limited surgical operation (patch angioplasty, endarterectomy)- elective placement of a new bypass can be performed after full work-up (cardiac, vein mapping, etc.),Despite initial success, sometimes,Despite initial success, sometimes,Acute arterial thrombosis remains a vexing clinical entity Clinical outcomes following thrombectomy or thrombolysis are occasionally suboptimal secondary to vasospasm or rethrombosisRethrombosis occurs in up to 20% of patients (thrombogenic intimal surfacethought to cause platelet dependent clot)The effects of thrombus on endothelium have not been completely elucidated,Clinical correlation of thrombus-endothelial interaction,Digital subtraction angiogram of the R brachial artery after successful removal of an acute embolus.,Vasospasm = Thrombus-induced Endothelial Dysfunction?,Vasospasm relieved by NO donorsVasospasm is hard to treat if there is persistent clotThrombosis causes endothelial dysfunction in multiple animal modelsDepressed Nitric oxide (NO) levels are implicated as the source of the endothelial dysfunction,Tissue Bath system,Reil, et al EJVES 2000,Luminal Thrombus,SEM- Post-thrombosis,Factor VIII Immunohistochemistry,Normal Post-thrombosis,Thrombolysis Experiments,*,*,p=0.003,p=0.007,Effect of L-arginine supplementation on EDR and NO Production,Kashyap et al., JVS 2001,Western Blot,Effect of thrombosis on EDR of rat infrarenal aortic ring segments (IRA). EDR of control (nonthrombosed) rat IRA (n=5) is compared with IRAs after 1 hr of thrombosis (n=4). *P0.05, *P0.001 by two way ANOVA.,*,*,*,*,*,Endothelial Dependent Relaxation (EDR),Effect of specific arginase inhibition on EDR of thrombosed IRA. Pretreatment with arginase inhibitor restores the EDR in thrombosed IRA. n=3 in all the three groups. *P0.001 BEC vs thrombosed IRA analysis of variance. #P0.01, #P3,Arginase II,How does thrombus cause endothelial dysfunction?Mechanistic insights,Causes endothelial cell loss-NoScavenges NO-PerhapsDecreases NO secretion or diffusion-NoDecreases NO production by affecting eNOS-NoAffects L-arginine transport via the Y+ channel- NoIncreases endogenous vasoconstrictorNoDecreases L-arginine availabilityYes Thrombin increases arginase activity,The Fate of L-arginine,Future Studies,In vitro studies (endothelial cells)Thrombin, fibrin exposure with arginase blockadeActivated neutrophil effectsIn vivo studies (rodent models)Arginase blockade in thrombosed infrarenal arterial segmentsMouse model, knockoutsHuman studiesExplanted human arteriesendothelial functionRCT using thrombolysis and L-arginine supplementation,Conclusions,Endothelial cells exposed