Yiu Wai-ki, Cheng Stephen W K, Sumpio Bauer E
Department of Vascular Surgery, Yale University School of Medicine, New Haven, and Veterans Administration Health Care System, West Haven, Connecticut 06520-8062, USA.
J Vasc Interv Radiol. 2008 Jun;19(6):925-30. doi: 10.1016/j.jvir.2008.02.007. Epub 2008 Apr 18.
Cryoplasty combines mechanical dilation with supercooling of the vessel and has shown encouraging preliminary results in the management of atherosclerotic lesions. However, the mechanisms of action and the optimum inflation regimen are still not well established. This study investigates the effects of single and dual supercooling and rewarming cycles on the survival responses of smooth muscle cells (SMCs) and endothelial cells (ECs).
Bovine aortic SMCs and ECs were cultured separately in six-well plates with medium supplemented with 10% fetal bovine serum. In the one-cycle treatment group, the cells were supercooled for 60 seconds to -10 degrees C and then rewarmed rapidly in a water bath at 37 degrees C for another 60 seconds. Two-cycle treatment was done by supercooling and rewarming the cells twice. The samples were then put into an incubator at 37 degrees C for 0, 6, 12, and 24 hours. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling was used to measure apoptosis and phospho-Akt immunohistochemistry and immunoblot analysis were employed to assess activation of Akt.
A significant increase of apoptotic cells was observed in the two-cycle procedure versus the one-cycle procedure. In both groups, there were more apoptotic SMCs than ECs. Akt activation was higher in ECs by a factor of three compared with SMCs (P < .05).
The higher apoptotic rate and the absence of Akt activation of SMCs versus controls in both treatment groups may imply the potential of a lower restenosis rate, especially after two cycles of supercooling and rewarming. Further in vivo and clinical investigations are needed to confirm results of the in vitro testing.
冷冻血管成形术将机械扩张与血管过冷相结合，在动脉粥样硬化病变的治疗中已显示出令人鼓舞的初步结果。然而，其作用机制和最佳膨胀方案仍未完全明确。本研究调查单次和双次过冷及复温循环对平滑肌细胞（SMC）和内皮细胞（EC）存活反应的影响。
牛主动脉SMC和EC分别在补充有10%胎牛血清的培养基的六孔板中培养。在单循环治疗组中，将细胞过冷60秒至-10℃，然后在37℃水浴中快速复温60秒。双循环治疗是将细胞过冷和复温两次。然后将样品置于37℃培养箱中0、6、12和24小时。采用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记法测量凋亡，采用磷酸化Akt免疫组织化学和免疫印迹分析评估Akt的激活。
与单循环程序相比，双循环程序中观察到凋亡细胞显著增加。在两组中，凋亡的SMC比EC更多。与SMC相比，EC中的Akt激活高3倍（P <.05）。
在两个治疗组中，与对照组相比，SMC的凋亡率较高且缺乏Akt激活可能意味着再狭窄率较低的可能性，尤其是在过冷和复温两个循环后。需要进一步的体内和临床研究来证实体外测试的结果。
