HUMAN MICROVASCULAR ENDOTHELIAL CELL-EXTRACELLULAR MATRIX INTERACTIONIN CELLULAR GROWTH-STATE DETERMINATION

We introduce two methods, both of which are based on cellular-extracel lular matrix interaction, which will facilitate the study of human mic rovascular endothelial cells. One method describes the means to obtain a G1 population baseline in human microvasclular endothelial cells. B ecause of the contribution of the extracellular matrix in endothelial cell growth, synchronization in G1 was possible only after the incorpo ration of angiostatic levels of heparin and hydrocortisone into the ex tracellular matrix. In the second method, we demonstrate that selectiv e perturbation of human microvascular endothelial cell-extracellular m atrix interactions results in the induction of a transitional growth s tate, between proliferative and differentiated growth states, in human microvascular endothelial cells. In the functional, microtubule forma tion assays, transitional growth state endothelial cells display rates that are indermediate between those obtained from differentiated and proliferative endothelial cells. Our results demonstrate the importanc e of the human microvascular endothelial cell-extracellular matrix int eraction in the determination of cellular growth state. Our findings a lso imply that responsiveness of microvascular endothelial cells to th eir cellular-extracellular matrix environs is highest during the diffe rentiated growth state.