When human hearts are injured, as during a heart attack, healthy tissue normally cant regrow. Researchers now demonstrate in rats that a sponge-like patch, soaked in a compound called periostin and placed over the injury, can not only get heart cells to begin dividing and making copies of themselves again, but also improves heart function. Their findings appear in the July 15 online edition of Nature Medicine.
Periostin is a component of the material that surrounds cells and is derived from the skin around bone. Though the mature heart only has tiny amounts, its abundant during fetal heart development, and increased amounts are also made after skeletal-muscle injury, bone fracture and blood vessel injury, stimulating mature, specialized cells to begin dividing again. Led by Bernhard Kuhn, MD, in the Department of Cardiology at Childrens Hospital Boston, the researchers theorized that placing periostin near the site of a myocardial infarction could help restore this growth-friendly environment and get heart tissue to regenerate.
Kuhn and colleagues at Massachusetts General Hospital and the Mount Sinai School of Medicine first stimulated mature, rod-shaped heart muscle cells (known as cardiomyocytes) with periostin in a Petri dish. About 1 percent of the cells entered the mitotic cell cycle namely, they began dividing and replicating. (One percent seems like a small proportion, but normally the percentage is close to zero.)
We found a small subpopulation of cells that could, with proper stimulation, re-enter the cell cycle, says Kuhn, who was awarded the Young Investigators Award for this research by the American College of Cardiology in March. This finding supports the idea that differentiated cardiomyocytes can proliferate.
Using a small patch fashioned from a sponge-like material called Gelfoam, they then moved to experiments in rats with induced heart attacks. In half the rats, a patch that had been incubated with peri
Contact: Anna Gonski
Children's Hospital Boston