ABSTRACT
Blood vessels were once considered to be an infrastructure of the body whose main function was to distribute blood throughout the body, and their biology was not a major concern for biologists, medical researchers, and physicians. When blood vessels were referred to as ‘living pipes’, this was understood to mean that they were made of alive cells and that new vessels could be made while existing ones could be remodeled and repaired. Recent progress in vascular biology, however, gave a new meaning to this term. We now know that blood vessels are metabolically highly active and perform multifaceted functions, such as synthesizing many types of physiologically active substances, receiving and transmitting chemical as well as mechanical signals, and controlling the passage of molecules and cells across the vessel wall.
