Modulation of endothelium and endothelial progenitor cell function by low-density lipoproteins: implication for vascular repair, angiogenesis and vasculogenesis.

The endothelium regulates vascular homeostasis and is responsible for angiogenesis, a process mediated by the sprouting of endothelial cells from pre-existing vessels. Several lines of evidence indicate that endothelial progenitor cells (EPCs) also play a role in adult neovascularization as well as in the maintenance of endothelial integrity and function. Hypercholesterolemia is associated with increased cardiovascular risk by inducing a cascade of events leading to endothelial dysfunction and injury. Growing evidence indicates that low-density lipoproteins (LDLs) impair endothelial reparative processes by inducing endothelial cell apoptosis but also by reducing the number and function of EPCs. The involvement of LDLs in mechanisms associated with vascular repair and neovascularization is also suggested by data from studies using lipid-lowering drugs (statins). This review is focused on the central role of the cholesterol pathway in the biology of the endothelium and EPCs.