By Ruth Steinhardt
Narine Sarvazyan and her team were trying to create universal-donor stem cells—cell transplants that the immune system would be less likely to reject—when something else caught her eye.
Observing a clump of cardiac muscle cells, called myocytes, she noticed that they were affecting blood flow in nearby vessels.
“I thought: Why not just use these cells and wrap them around [a vein] and make a little pump?” says Dr. Sarvazyan, a professor of pharmacology and physiology in the School of Medicine and Health Sciences.
The pump, essentially, would be a miniature heart—the kind of extremely simple circulation-aiding organ of which some worms, for example, have several.
The human heart is usually sufficient to circulate blood through the body. In the lower extremities, the movement of skeletal muscles helps squeeze veins, and valves ensure that pressure pushes blood only one way—back to the heart.
As people age, however, those valves often lose their efficacy and become one cause of blood pooling in the venous system. That pooling of the blood, called chronic venous insufficiency, can lead to varicose veins—which affect an estimated 25 percent of adults—as well as edema, ulcers, infections, or even amputations.