Scientists Create Model of Beating Heart Muscle

A bioengineered, experimental model of rhythmically beating heart muscle has been produced by the collaborative effort of a cardiologist and an orthopedist at the University of North Carolina at Chapel Hill (UNC, USA). They presented their model at the World Congress of Biomechanics in Calgary (Canada).

The model is a bioartificial trabeculum, or BAT. Trabecula are thin sections of cardiac tissue within the inner surface of the main pumping chambers of the heart. The model may prove to be a valuable tool for exploring cardiac disease or to generate tissue patches that might be applied to the surface of the heart or incorporated into a diseased heart as therapy.

Dr.Albert J. Banes, UNC professor of orthopedics, had earlier developed a special tissue plate used as a framework in which cells in a liquid collagen gel could remodel to form a more tissue-like structure. "We thought it would be better to grow cells in a dynamic environment, on a flexible substrate.”

Dr. Wayne E. Cascio, UNC associate professor of medicine, thought they could grow cardiac myocytes and make a cardiac muscle tissue-like material to test in culture. In developing the tissue model, Dr. Cascio and an assistant isolated cardiac myocytes from one-day-old rats. These were mixed in a solution of collagen and serum and allowed to gel under incubation in the special tissue plate developed by Dr. Banes. After four days in culture, the heart cells migrated toward the center of the gel to form a dense cord of tissue that extended between two tethers.

The tissue strand rhythmically contracts at 100 beats per minute, easily observed with a low-power microscope, say the researchers. Tests reveal striations and cell-to-cell coupling characteristic of cardiac tissue. "In my lab, we're specifically interested in generating cardiac myocytes with certain electrical or contractile properties by manipulating the genetics of the cells and then reforming them into functional tissue to assess their properties,” said Dr. Cascio.




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