S-2-hydroxyglutarate keeps endothelial cells in a dormant state, reveals study The inner surface of blood vessels is lined by a wafer-thin layer of cells known as the endothelium, which forms a crucial barrier between blood and the surrounding tissue. The single-layered cell structure promotes the exchange of oxygen and nutrients, while simultaneously preventing the uncontrolled leakage of blood components. Only when the metabolic needs of the surrounding tissue increase, e.g., during growth, wound healing or tumor development, do endothelial cells abandon this stable cell association in orde...