Kim Antony Y, Walinsky Peter L, Kolodgie Frank D, Bian Ce, Sperry Jason L, Deming Clayton B, Peck Eric A, Shake Jay G, Ang Gregory B, Sohn Richard H, Esmon Charles T, Virmani Renu, Stuart R Scott, Rade Jeffrey J
Divisions of Cardiology, The Johns Hopkins School of Medicine, Baltimore, MD 21287, USA.
Circ Res. 2002 Feb 8;90(2):205-12. doi: 10.1161/hh0202.105097.
Thrombosis is the major cause of early vein graft failure. Our aim was to determine whether alterations in the expression of the anticoagulant proteins, thrombomodulin (TM) and the endothelial cell protein C receptor (EPCR), impair endothelial thromboresistance that may contribute to vein graft failure. Immunohistochemical staining of autologous rabbit vein graft sections revealed that the expression of TM, but not EPCR, was reduced significantly early after graft implantation. Western blot analysis revealed that TM expression was reduced by >95% during the first 2 weeks after implantation, with gradual but incomplete recovery by 42 days. This resulted in up to a 95% reduction in the capacity of the grafts to activate protein C and was associated with an increase in bound thrombin activity, which peaked on day 7 at 28.7 +/- 3.8 mU/cm(2) and remained elevated for more than 14 days. Restoration of TM expression using adenovirus vector-mediated gene transfer significantly enhanced the capacity of grafts to activate protein C and reduced bound thrombin activity on day 7 to levels comparable to that of normal veins (5.7 +/- 0.4 versus 5.2 +/- 1.1 mU/cm(2), respectively, P=0.74). Surprisingly, neointima formation was not affected by this inhibition of local thrombin activity. These data suggest that the early loss of TM expression significantly impairs vein graft thromboresistance and results in enhanced local thrombin generation. Although enhanced local thrombin generation may predispose to early vein graft failure due to thrombosis, it does not seem to contribute significantly to late vein graft failure due to neointimal hyperplasia.
血栓形成是早期静脉移植物功能衰竭的主要原因。我们的目的是确定抗凝蛋白血栓调节蛋白（TM）和内皮细胞蛋白C受体（EPCR）表达的改变是否会损害内皮抗血栓形成能力，而这种能力可能导致静脉移植物功能衰竭。对自体兔静脉移植物切片进行免疫组织化学染色显示，移植后早期TM的表达显著降低，而EPCR的表达未受影响。蛋白质印迹分析显示，植入后的前2周内TM表达降低了95%以上，至42天时逐渐但未完全恢复。这导致移植物激活蛋白C的能力降低了95%，并伴有结合凝血酶活性增加，在第7天达到峰值，为28.7±3.8 mU/cm²，并持续升高超过14天。使用腺病毒载体介导的基因转移恢复TM表达可显著增强移植物激活蛋白C的能力，并将第7天的结合凝血酶活性降低至与正常静脉相当的水平（分别为5.7±0.4和5.2±1.1 mU/cm²，P = 0.74）。令人惊讶的是，局部凝血酶活性的这种抑制并未影响新生内膜形成。这些数据表明，TM表达的早期丧失显著损害静脉移植物的抗血栓形成能力，并导致局部凝血酶生成增加。尽管局部凝血酶生成增加可能因血栓形成而导致早期静脉移植物功能衰竭，但它似乎对因新生内膜增生导致的晚期静脉移植物功能衰竭没有显著影响。
