Miller V M, Bergman R T, Gloviczki P, Brockbank K G
Department of Surgery, Mayo Clinic Rochester, MN 55905.
J Vasc Surg. 1993 Aug;18(2):216-26.
Experiments were designed to determine the function of the endothelium and smooth muscle in cryopreserved and fresh canine saphenous vein allografts.
Reversed interposition saphenous vein grafts were implanted into the femoral arteries of two groups of dogs: group 1 received one freshly harvested saphenous vein allograft and group 2 received one cryopreserved saphenous vein allograft. The contralateral femoral artery in each group was replaced with a freshly harvested autogenous saphenous vein. Animals received oral cyclosporine alone (n = 3) or in combination with aspirin (325 mg/day; n = 20).
Four weeks after surgery, none of the cryopreserved grafts was patent in the group treated with cyclosporine alone. All grafts were patent in animals treated with cyclosporine and aspirin. At 4 weeks, blood flow through cryopreserved allografts was significantly greater than in freshly harvested allografts. Platelet deposition was comparable in cryopreserved and freshly harvested allografts immediately after implantation and at 4 weeks. Rings cut from the grafts were suspended for the measurement of isometric force in organ chambers. alpha-Adrenergic agonists and endothelin caused concentration-dependent contractions in fresh autografts and allografts. After submaximal contraction with prostaglandin F2 alpha in these same grafts, calcium ionophore and thrombin caused relaxations in rings with endothelium, and nitric oxide caused relaxations in rings without endothelium. Cryopreserved allografts did not respond to any of the agonists tested. Histologic examination of the tissue indicated smooth muscle cells in cryopreserved grafts; evidence of rejection was observed in all allografts.
These results indicate that cryopreserved allografts remain patent with antiplatelet and immunosuppressive therapy in spite of loss of functional smooth muscle.
设计实验以确定内皮细胞和平滑肌在冷冻保存的和新鲜的犬隐静脉同种异体移植物中的功能。
将倒置的隐静脉移植物植入两组犬的股动脉：第1组接受1条新鲜采集的隐静脉同种异体移植物，第2组接受1条冷冻保存的隐静脉同种异体移植物。每组的对侧股动脉用新鲜采集的自体隐静脉替代。动物单独口服环孢素（n = 3）或联合阿司匹林（325毫克/天；n = 20）。
术后4周，单独接受环孢素治疗的组中，冷冻保存的移植物无一通畅。接受环孢素和阿司匹林治疗的动物中，所有移植物均通畅。4周时，通过冷冻保存的同种异体移植物的血流量显著高于新鲜采集的同种异体移植物。植入后即刻及4周时，冷冻保存的和新鲜采集的同种异体移植物中的血小板沉积相当。从移植物上切下的环被悬挂在器官浴槽中以测量等长力。α-肾上腺素能激动剂和内皮素在新鲜自体移植物和同种异体移植物中引起浓度依赖性收缩。在这些相同的移植物中用前列腺素F2α进行次最大收缩后，钙离子载体和凝血酶在有内皮的环中引起舒张，一氧化氮在无内皮的环中引起舒张。冷冻保存的同种异体移植物对所测试的任何激动剂均无反应。组织学检查显示冷冻保存的移植物中有平滑肌细胞；在所有同种异体移植物中均观察到排斥反应的证据。
这些结果表明，尽管功能性平滑肌丧失，但冷冻保存的同种异体移植物在抗血小板和免疫抑制治疗下仍保持通畅。
