For those suffering from common, but deadly, heart diseases, stem cell biology represents a new medical frontier. Researchers are working toward using stem cells to replace damaged heart cells and literally restore cardiac function.

Most heart therapies prevent cardiovascular damage by lowering blood pressure or cholesterol. No existing treatment actually reverses heart failure, which weakens cardiac muscle and often follows a heart attack. More than 5 million Americans have the disorder, according to the American Heart Association.

The new experiments all use adult stem cells harvested from blood, bone, muscle and fat. In most studies they are gathered from a patient’s own organs, purified in the laboratory, then injected back into an individual’s heart.

How might stem cells play a part in repairing the heart? Stem cells may help form new blood vessels, which the damaged heart needs, and that the ultimate treatment may combine adult cells to stimulate blood flow and embryonic cells to form new muscle. Researchers now know that under highly specific growth conditions in laboratory culture dishes, stem cells can be coaxed into developing as new cardiomyocytes and vascular endothelial cells. Scientists are interested in exploiting this ability to provide replacement tissue for the damaged heart. This approach has immense advantages over heart transplant, particularly in light of the paucity of donor hearts available to meet current transplantation needs.

Here is a news article Stem cells spotlighted in Baxter heart study
about a clinical study, to be completed in 2009, testing if self stem cells can strengthen human heart.

Please refer to this report Can Stem Cells Repair a Damaged Heart? from NIH for early evidence of stem cell usefulness in rodent models.