Higman D J, Greenhalgh R M, Powell J T
Department of Surgery, Charing Cross and Westminster Medical School, London, UK.
Br J Surg. 1993 Oct;80(10):1242-5. doi: 10.1002/bjs.1800801007.
Samples of proximal saphenous vein were obtained from heavy smokers and non-smokers: 28 were obtained at varicose vein surgery and eight at infrainguinal bypass surgery. The veins were prepared for histological examination and for mounting in an organ bath to measure changes in isometric tension. Vein rings from both smokers and non-smokers responded equally to sodium nitroprusside, a reagent that acts directly on smooth muscle cells, undergoing 90-100 per cent relaxation. The mean(s.e.m.) maximum relaxation in response to bradykinin of rings obtained at varicose vein surgery was 50.0(5.3) per cent in non-smokers compared with only 31.6(2.2) per cent in smokers (P = 0.03). Similarly, in specimens obtained at bypass surgery the mean(s.e.m.) maximum relaxation in smokers was only 25.1(6.3) per cent compared with 48.4(4.1) per cent in smokers (P = 0.04). Relaxation in response to the bradykinin stimulus was abolished in the presence of L-nitroarginine methyl ester, a specific inhibitor of the synthesis of endothelium-derived relaxing factor (EDRF). Preincubation of the vein rings with L-arginine, the precursor of EDRF, did not increase the vasorelaxation in smokers. The mean(s.e.m.) maximum relaxation in response to the calcium ionophore A23187 was 53.5(3.8) per cent in non-smokers compared with only 27.0(4.9) per cent in smokers (P = 0.01). The results indicate that heavy smokers have impaired release of EDRF in response to both bradykinin and calcium ionophore. This impairment may increase vasomotor tone, platelet aggregation and smooth muscle proliferation, thereby resulting in an increased risk of graft occlusion.
28个样本取自静脉曲张手术，8个样本取自腹股沟下搭桥手术。将这些静脉制备用于组织学检查，并置于器官浴中以测量等长张力的变化。吸烟者和非吸烟者的静脉环对硝普钠（一种直接作用于平滑肌细胞的试剂）的反应相同，均出现90%至100%的松弛。在静脉曲张手术中获取的静脉环对缓激肽反应的平均（标准误）最大松弛率，非吸烟者为50.0（5.3）%，而吸烟者仅为31.6（2.2）%（P = 0.03）。同样，在搭桥手术中获取的样本中，吸烟者的平均（标准误）最大松弛率仅为25.1（6.3）%，而非吸烟者为48.4（4.1）%（P = 0.04）。在存在内皮源性舒张因子（EDRF）合成特异性抑制剂L - 硝基精氨酸甲酯的情况下，对缓激肽刺激的松弛反应消失。用EDRF的前体L - 精氨酸对静脉环进行预孵育，并未增加吸烟者的血管舒张。非吸烟者对钙离子载体A23187反应的平均（标准误）最大松弛率为53.5（3.8）%，而吸烟者仅为27.0（4.9）%（P = 0.01）。结果表明，重度吸烟者对缓激肽和钙离子载体的反应中，EDRF的释放受损。这种损伤可能会增加血管运动张力、血小板聚集和平滑肌增殖，从而导致移植血管闭塞的风险增加。
