Cooper A, Heagerty A M
Department of Medicine, University Hospital of South Manchester, Manchester M23 9LT, United Kingdom.
Am J Physiol. 1998 Oct;275(4):H1482-8. doi: 10.1152/ajpheart.1998.275.4.H1482.
Vascular responses of human intramyocardial small arteries were examined in vitro to assess the influence of atherosclerosis and risk factors for coronary artery disease on endothelium-dependent relaxation. Recipient hearts were obtained from patients with ischemic (n = 14) and nonischemic (n = 13) cardiomyopathy undergoing heart transplantation. Small intramyocardial coronary arteries (mean internal diameter 313 +/- 11 micrometers) were mounted on a wire myograph for measurement of morphology and isometric tension. Vasodilation was examined after preconstriction with U-46619, a thromboxane A2 analog. Endothelium-dependent relaxation to acetylcholine and bradykinin was impaired in patients with ischemic compared with nonischemic cardiomyopathy (P < 0.01 and P < 0.001, respectively). Endothelium-independent relaxation to sodium nitroprusside was preserved. Incubation with L-arginine (3 mmol/l) did not improve endothelium-dependent relaxation to acetylcholine or bradykinin. With the use of stepwise multivariate analysis, hypercholesterolemia, but no other risk factor for atherosclerosis, was independently associated with impaired endothelium-dependent relaxation to acetylcholine (r = -0.50, P = 0.05) but not to bradykinin. Endothelial dysfunction in intramyocardial small arteries may predispose patients with nonobstructive epicardial atherosclerosis and hypercholesterolemia to myocardial ischemia.
在体外检测人心肌内小动脉的血管反应，以评估动脉粥样硬化和冠状动脉疾病危险因素对内皮依赖性舒张的影响。接受心脏移植的患者心脏来自缺血性心肌病（n = 14）和非缺血性心肌病（n = 13）患者。将心肌内小冠状动脉（平均内径313±11微米）安装在钢丝肌动描记器上，用于测量形态和等长张力。在用血栓素A2类似物U - 46619预收缩后检测血管舒张情况。与非缺血性心肌病患者相比，缺血性心肌病患者对乙酰胆碱和缓激肽的内皮依赖性舒张受损（分别为P < 0.01和P < 0.001）。对硝普钠的非内皮依赖性舒张得以保留。用L - 精氨酸（3 mmol/l）孵育并未改善对乙酰胆碱或缓激肽的内皮依赖性舒张。使用逐步多变量分析，高胆固醇血症而非动脉粥样硬化的其他危险因素与对乙酰胆碱的内皮依赖性舒张受损独立相关（r = -0.50，P = 0.05），但与缓激肽无关。心肌内小动脉的内皮功能障碍可能使非梗阻性心外膜动脉粥样硬化和高胆固醇血症患者易发生心肌缺血。
