Mechanisms regulating endothelial cell barrier function

Endothelium forms a physical barrier that separates blood from tissue. Comm unication between blood and tissue occurs through the delivery of molecules and circulating substances across the endothelial barrier by directed tran sport either through or between cells. Inflammation promotes macromolecular transport by decreasing cell-cell and cell-matrix adhesion and increasing centripetally directed tension, resulting in the formation of intercellular gaps. Inflammation may also increase the selected transport of macromolecu les through cells. Significant progress has been made in understanding the molecular and cellular mechanisms that account for constitutive endothelial cell barrier function and also the mechanisms activated during inflammatio n that reduce barrier function. Current concepts of mechanisms regulating e ndothelial cell barrier function were presented in a symposium at the 2000 Experimental Biology Conference and are reviewed here.