Resistance arteries remain subject to pulsatility, a potent regulator of large elastic artery tone and structure but the effect in incompletely understood. Extracorporeal circulation (CPB) during cardiac surgery is often associated with absence of pulsatility, wich may affect vascular tone. To define the rôle of the vascular wall in the inflammatory process that may occur with of without pulsatility, we studied resistance arteries functions ex-vivo. We mesured vascular reactivity, oxidative stress and inflammation in the arterial wall. In isolated rat mesentric resistance arteries, the pulsatility lead to decrease myogenic tone and increase flow mediated dilation. There is no modification of pharmacological reactivity of the arteries without pulsatility. The lack of pulsatility during 3 hours induce an importante production of inflammation proteins and reative oxygen species (ROS), but not in pulsed vessels. An antioxydan treatment prevent ROS and inflammation production. The pulsatility is essential in the microcirculation. De lack of pulsatility in resistance arteries increase oxydative stress, wich in turn induced inflammation and preferentially alterred pressure and flow-dependant tone, wich play a key role in control of local blood flow.
Mechanotransduction of flow and pressure in microcirculation : Role of the pulsatility