L-Glutamine Transporter in Cultured Human Umbilical Vein Endothelial Cells: Characteristics and Role in Oxidant Stress

Abstract

The vascular endothelium may be subject to oxidative stress and injury in the pathogenesis of many diseases including inflammation and atherosclerosis (Morel et al., 1984). Sublytic injury of the endothelium is associated with a widespread change in cellular function including changes in vascular permeability (Block 1991), depletion of ATP and inhibition of glycolysis (Hyslop et al., 1988). Availability of extracellular L-glutamine may act as a substrate for ATP generation and thus protect against oxidative stress (Hinshaw et al., 1990). In addition, L-glutamine regulates the transport of L-cystine (Bannai and Ishii, 1988) and may have a further protective role in oxidant stress by maintaining levels of intracellular Glutathione. We have characterized the transport of L-glutamine in human umbilical vein endothelial cells (HUVEC) and performed preliminary studies to set up a model of oxidative stress in this cell type.