The interior lining of blood vessels is known as the endothelium. Endothelial cells, which make up this inside layer of all blood vessels, are remarkably responsive to changes that occur in the blood and tissues, both under normal conditions and in disease states, sending signals back to the blood and tissues to organize a response. Endothelial cells initiate and direct the growth of new blood vessels within a tissue that is not receiving a sufficient supply of oxygen and nutrients. This growth of new blood vessels can be either beneficial or detrimental to a person’s health. When blocked blood vessels are contributing to the lack of sufficient blood supply (e.g. hardening of the arteries or diabetes), the body’s creation of new blood vessels can prevent tissue damage and promote healing. However, new blood vessels also required for cancer growth by providing the tumour with the oxygen and nutrients it needs. Dr. Aly Karsan is studying several molecules on the surface of endothelial cells to determine how they regulate the growth of new blood vessels. With greater knowledge about the molecular processes underpinning blood vessel growth, he hopes to identify new ways to either promote or restrict these processes to combat a variety of diseases.