Kubli S, Waeber B, Dalle-Ave A, Feihl F
Department of Internal Medicine, Lausanne University Hospital, Switzerland.
J Cardiovasc Pharmacol. 2000 Nov;36(5):640-8. doi: 10.1097/00005344-200011000-00014.
Endothelial dysfunction might be an important and early event in the pathogenesis of major cardiovascular diseases. Therefore, the evaluation of endothelial function in humans may be of great clinical relevance. Usual methods for that purpose are either invasive and/or technically demanding. In the dermal microcirculation, endothelial function may be assessed noninvasively from the laser Doppler measurement of increases in blood flow after either the transdermal application of acetylcholine by iontophoresis, or the release of transient arterial occlusion (reactive hyperemia). An endothelium-independent response may be provided by the iontophoresis of sodium nitroprusside. This approach is notable for technical simplicity, but of uncertain reproducibility. Sixteen young, healthy, nonsmoking males were examined in the fasting state. Changes in skin blood flow were measured with a laser Doppler imager during the iontophoresis of acetylcholine and sodium nitroprusside, as well as during reactive hyperemia, on two different days, at each of two different sites on the volar face of the forearm. Nonspecific effects related to the stimulation of terminal nerve fibers by the iontophoretic current were suppressed by prior surface anesthesia. The iontophoresis of acetylcholine and sodium nitroprusside induced a seven- to eightfold increase in dermal blood flow. The corresponding figure for peak reactive hyperemia was approximately fourfold. The mean coefficients of variation of responses recorded on different days, on the same site, in the same individual were <10% for iontophoresis of acetylcholine and for peak reactive hyperemia, and between 10 and 20% for iontophoresis of sodium nitroprusside. This day-to-day variation was significantly smaller than the site-to-site variation (p < 0.01 for all three responses). Endothelium-dependent and -independent responses of dermal blood flow evaluated with laser Doppler imaging are highly reproducible from day to day, at least in healthy nonsmoking young male subjects, and provided some simple precautions are observed, foremost among which is the strict standardization of the recording site. These observations may have implications for the testing of endothelial function in clinical studies.
内皮功能障碍可能是主要心血管疾病发病机制中的一个重要早期事件。因此，评估人体的内皮功能可能具有重大的临床意义。为此目的的常用方法要么具有侵入性，要么对技术要求较高。在皮肤微循环中，可以通过激光多普勒测量经皮离子电渗法应用乙酰胆碱后或短暂性动脉闭塞（反应性充血）释放后血流量的增加，以无创方式评估内皮功能。硝普钠离子电渗可提供非内皮依赖性反应。这种方法的显著特点是技术简单，但可重复性不确定。对16名年轻、健康、不吸烟的男性在空腹状态下进行了检查。在两天内，于前臂掌面的两个不同部位，在乙酰胆碱和硝普钠离子电渗过程以及反应性充血期间，用激光多普勒成像仪测量皮肤血流变化。通过事先进行表面麻醉，抑制了离子电流刺激终末神经纤维产生的非特异性效应。乙酰胆碱和硝普钠离子电渗引起皮肤血流增加7至8倍。反应性充血峰值的相应数字约为4倍。在同一天、同一部位、同一个体记录的反应的平均变异系数，乙酰胆碱离子电渗和反应性充血峰值均<10%，硝普钠离子电渗为10%至20%。这种每日变化明显小于部位间变化（所有三种反应的p<0.01）。至少在健康不吸烟的年轻男性受试者中，用激光多普勒成像评估的皮肤血流的内皮依赖性和非依赖性反应在每日之间具有高度可重复性，并且只要遵守一些简单的预防措施，其中最重要的是记录部位的严格标准化。这些观察结果可能对临床研究中内皮功能的检测有影响。
