As he studies these cells that line blood vessels, this vascular biologist at the Medical College of Georgia focuses on the proteins and growth factors that regulate their normal processes, including proliferation, differentiation, migration and death.

He wants to better understand how these cells interact with their environment because there are still many unanswered questions.

But he also wants to know because tumors sometimes commandeer these cells' ability to grow new blood vessels that bring life-sustaining nutrients and oxygen. "For most tumors to become any larger than 2 to 3 millimeters (a small fraction of an inch) in diameter, they have to recruit blood vessels," said Dr. Motamed.

This new vessel growth, called angiogenesis, can be beneficial. An injury can throw an angiogenic switch, activating a previously quiet endothelial cell. "As a result of activation, the endothelial cell loses its contact with the matrix (the milieu cells live in), elongates and invades the surrounding, stromal tissue," Dr. Motamed said. The cell then begins to proliferate, forming the lumen through which blood will eventually flow, and recruits supporting cell types and matrix components to form a new, functional vascular bed that is believed to accelerate wound healing.

The fact that many tumors also activate angiogenesis to survive has helped make it a hot topic in science. Dr. Motamed, who came to MCG in September from The Hope Heart Institute in Seattle, has his eye on the role of basic fibroblast growth factor in promoting angiogenesis and a protein called SPARC, which seems to have multiple roles in cancer and new blood vessel formation.

"SPARC is a protein most abundant during tissue remodeling and repair," said Dr. Motamed. The protein has many functions inclu
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Contact: Toni Baker
tbaker@mail.mcg.edu
706-721-4421
Medical College of Georgia
20-Feb-2003