Akira Kakuta

Effect of amplitude and duration of impulsive pressure on endothelial permeability in in vitro fluid percussion trauma

BackgroundIntracranial pressure changes during head impact cause brain injuries such as vasogenic edema and cerebral contusion. However, the influence of impulsive pressure on endothelial function has not yet been fully studied in vitro. In this study, we developed a pressure loading device that produced positive and negative pressures by modifying an in vitro fluid percussion model and examined the effects of the amplitude and duration of the pressures on endothelial permeability.MethodsHuman umbilical vein endothelial cells were subjected to three types of positive pressure (average amplitude/average duration of 352 kPa/23xa0ms, 73 kPa/27xa0ms, and 70 kPa/44xa0ms) and three types of negative pressure (−72 kPa/41xa0ms, −67 kPa/104xa0ms, and −91 kPa/108xa0ms), and the transendothelial electrical resistance (TEER) was measured between 15xa0min and 24xa0h after pressure loading for quantifying the formation of an integral monolayer of endothelial cells. After loading, vascular endothelial- (VE-) cadherin, an endothelium-specific cell-cell adhesion molecule involved in endothelial barrier function, was stained and observed using fluorescence microscopy.ResultsThe pressure loading device could produce positive pressure pulses with amplitudes of 53–1348 kPa and durations of 9–29.1xa0ms and negative pressure pulses with amplitudes of −52–−93 kPa and durations of 42.9–179.5xa0ms. The impulsive pressure reduced the TEER associated with the change in VE-cadherin localization. Additionally, TEER decreased considerably at 15xa0min and 6xa0h post-loading, with these changes being significant in positive pressure with larger amplitude and shorter duration and in all types of negative pressures compared to pre-loading.ConclusionsThe changes in intracranial pressure during head impact impair endothelial barrier function by the disruption of the integrity of endothelial cell-cell junctions, and the degree of increase in endothelial permeability depends on the amplitude, duration, and direction (compressive and tensile) of the impulsive pressure.