Cardiac Development
 

studies the biochemistry of cell proliferation and cell differentiation. Heart muscle cells, unlike other muscles, do not repair themselves. As a result, when a person suffers a heart attack, muscle cells that die are not replaced. Instead, scar tissue grows where the muscle once was. The inability of heart muscle cells to reproduce prevents them from becoming cancerous. But it also means that no new heart cells are grown in the adult heart. In an animal experiment that one day may lead to repair of human hearts, Dr. Claycomb and his collaborators showed that genetically engineered cells can be injected into cardiac muscle to replace tissue killed by a heart attack. This experiment demonstrated, for the first time, that mammalian heart cells can be genetically engineered to grow and reproduce endlessly in a test tube. The Claycomb lab has also shown that genetically altered mouse heart cells could survive and beat like normal heart muscle cells when placed into the damaged heart of a pig. This work challenges the dogma that it is not possible to create a cell line that displays the unique features of an intact heart. Dr. Claycomb's current research is concerned with understanding the regulation of cell division, DNA replication and selective gene activation and repression in the differentiating and aging cardiac muscle cell. Terminally differentiating cardiac muscle cells in the intact animal and in tissue culture are being utilized as experimental systems. Recent work has focused on the regulation of cardiac muscle cell division by proto-oncogenes and tumor suppressor genes and their protein products. Click here to learn more about Dr. Claycomb's research.