Directly detect age-related changes in electrical impedance of single vascular endothelial cell without using biomarkers.Design and Method:
Aging is one of the major factors in cardiovascular disease (CVD). However, it is difficult to differentiate changes in cardiovascular system between the aged and the diseased. If the difference could be characterized clearly, it would be potential help to understand pathophysiology. In this study, micro-electrochemical impedance spectroscopy (μEIS) with a pressure-dependent membrane actuator for cell-capturing was used to characterize age-related changes in electrical impedance of sorted single vascular endothelial cell from dissected hearts of transgenic zebrafish (fli1a:EGFP). The electrical impedance for each group (3, 4, and 18-month-old) was measured 30 times from 1 kHz to 1 MHz under 250, 300, and 350 kPa of capturing pressures, respectively.Results:
Maximum differences in the average electrical impedance among the three cell groups were observed at 1 MHz, and these differences were statistically significant for all capturing pressures (p < 0.05, one-way ANOVA). Figure 1 shows the changes in the electrical impedance depending on different ages at different capturing pressure. Our results show that both electrical parameters (resistance and reactance) similarly change with aging for all capturing pressures. The resistance increased monotonously with aging, whereas the reactance decreased in 4-month-old and then increased in 18-month-old cells. Especially, 350kPa of capturing pressure could clearly discriminate electrical impedance of different aging groups.Conclusions:
We applied μEIS to zebrafish vascular endothelial cells at different ages and found that resistance increased monotonously with aging, while reactance decreased during early ages and increased in aged cells. Age-related changes in resistance and reactance can be attributed to the changes in fluidity and permeability of cells due to metabolic remnants such as hydrogen ion and reactive oxygen species. In this context, the proposed μEIS could be considered as a potential diagnostic tool for CVD to detect age-related changes.