VOA常速英语:Nanostructure Promotes Blood Vessel Growth

U.S. researchers have developed a new way to promote the growth of blood vessels which potentially could improve treatment in diabetes, organ transplants, stroke, and heart attack.

The veins and arteries that snake through the body are something like a highway network, a pathway to transport oxygen and other nutrients to cells.

When blood vessels get blocked, the tissue being supplied can die. That's what happens in a heart attack, for example: a blocked artery leads to death of heart muscle cells.

Scientists have been trying to harness the body's own mechanism for growing blood vessels, but researcher Samuel Stupp of Northwestern University in Chicago explains they want to improve on nature.

"So we want to imitate what the body naturally does, but we want to be able to do it on demand, exactly in the place where it's needed in, and we want the blood vessels to grow rapidly."

The body naturally tells, or signals cells to start growing new blood vessels with a protein called VEGF (vascular endothelial growth factor), but studies have found that treating patients with VEGF is very expensive, the effect doesn't last long, and the blood vessels grow slowly.

So Stupp and his colleagues designed a tiny molecular structure covered with peptides that mimic the signaling function of the body's own VEGF.

"So they can be injected in tissue, and they can then signal cells directly and have a therapeutic effect," referring to the growth of new blood vessels.

Stupp and team used laboratory mice to test the concept. The researchers cut out a piece of artery from the animals' legs to simulate the loss of circulation often faced by people with diabetes. "And we observed that circulation was restored within three to four weeks," Stupp says.

Human trials are still in the future, but Stupp says in theory this new treatment would help in a number of medical scenarios, such as a heart attack - when a blood clot cuts off the heart's own blood supply.

"So if you had a therapy that you could introduce into the heart muscle, you could jump-start the growth of blood vessels and possibly save more of the heart muscle that has been affected by the heart attack."