There is plenty of experimental evidence to show that endothelial cells are sensitive to flow, but very little attention has been paid to fluid pressure or pressure gradients which are used to drive viscous flow. In fact there are two principal physical forces exerted on the blood vessel wall by the passage of intra-luminal blood: pressure and shear. In order to analyze their independent effects, these two stresses were applied to cultured cells by means of two different bioreactors: the pressure-controlled bioreactor (PCB) and the laminar flow bioreactor (LFB), in which controlled levels of pressure and shear stress can be respectively generated. Using the bioreactor systems, endothelin-1 and nitric oxide release from human umbilical vein endothelial cells (HUVEC) were measured in varying conditions of shear stress and pressure. As result, a decrease of endothelin-1 production from the cells cultured in both bioreactors, with respect to the controls, was observed, whereas nitric oxide synthesis was up-regulated only in the presence of shear stress but not modulated by hydrostatic pressure. These results show that the two hemodynamic forces acting on blood vessels affect endothelial cell function in different ways, and that both should be considered when planning in vitro experiments in the presence of flow. Understanding the individual and synergic effects of the two forces could provide important insights into physiological and pathological processes involved in vascular remodeling and adaptation.
Hydrostatic pressure and shear stress affect endothelin-1 and nitric oxide release by endothelial cells in bioreactors
AHLUWALIA, ARTI DEVI;
2013-01-01
Abstract
There is plenty of experimental evidence to show that endothelial cells are sensitive to flow, but very little attention has been paid to fluid pressure or pressure gradients which are used to drive viscous flow. In fact there are two principal physical forces exerted on the blood vessel wall by the passage of intra-luminal blood: pressure and shear. In order to analyze their independent effects, these two stresses were applied to cultured cells by means of two different bioreactors: the pressure-controlled bioreactor (PCB) and the laminar flow bioreactor (LFB), in which controlled levels of pressure and shear stress can be respectively generated. Using the bioreactor systems, endothelin-1 and nitric oxide release from human umbilical vein endothelial cells (HUVEC) were measured in varying conditions of shear stress and pressure. As result, a decrease of endothelin-1 production from the cells cultured in both bioreactors, with respect to the controls, was observed, whereas nitric oxide synthesis was up-regulated only in the presence of shear stress but not modulated by hydrostatic pressure. These results show that the two hemodynamic forces acting on blood vessels affect endothelial cell function in different ways, and that both should be considered when planning in vitro experiments in the presence of flow. Understanding the individual and synergic effects of the two forces could provide important insights into physiological and pathological processes involved in vascular remodeling and adaptation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
