Abstract
For early diagnosis of atherosclerosis, functional assessment of endothelial cells (ECs) and smooth muscle cell (SMCs) is important. Evaluation of ECs function has already been established as flow mediated dilation (FMD), but that of SMCs has been hardly reported. To assess SMC function, we developed a method to evaluate smooth muscle contractility following stepwise dilation of human brachial artery by applying 50 mmHg of negative pressure to an airtight chamber attached to the upper arm for 120s (Pressure-mediated contraction, PMC). However, displacement of brachial artery following negative pressure application sometimes hampers the accuracy of PMC measurement. To overcome this problem, we have been developing a method to apply chopped negative pressure synchronized with electrocardiogram (cPMC). By measuring artery diameter during unloading phase, the displacement of the artery could be minimized. We also found that cPMC could reduce the time for measurement: application of cPMC for 30 s could induce vasoconstriction comparable to that caused by application of continuous negative pressure for 120 s. cPMC is an efficient method for evaluating SMC function.
