Blood vessels of the skin are composed of a number of cellular and non-cellular elements. The predominant cell type in all skin blood vessels is the endothelial cell. Endothelial cells form the interface between intravascular and extravascular compartments and serve as a selective barrier for the diffusion of cells and macromolecules between these two compartments. The endothelial cells lining blood vessels of the skin share features of endothelial cells elsewhere in the body, but they also exhibit several skin specific characteristics. They are active participants in a variety of physiological processes. These include wound healing, control of hemostasis, temperature regulation, and the modulation of inflammation/leukocyte trafficking. The structure and function of endothelial cells are differentially regulated in space and time. Endothelial cell proliferation, quiescence, apoptosis, and senescence are the four principal cytologic states that set the cutaneous microvascular in a dynamic balance between maintenance and remodeling.HDMEC from AcceGen Research Laboratories are isolated from human dermal tissue. HDMEC are cryopreserved on passage one and delivered frozen. Each vial contains ＆gt;5×10^5 cells in 1 ml volume. HDMEC are characterized by immunofluorescent method with antibodies to vWF/Factor VIII and CD31 （P-CAM） and by uptake of DiI-Ac-LDL. HDMEC are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HDMEC are guaranteed to further expand for 15 population doublings in the conditions provided by AcceGen Research Laboratories.
