According to a study is published in The Journal of the American Medical Association, May 20 edition, Dr. Douwe E. Atsma - an interventional cardiologist at Leiden University Medical Center, Netherlands - and colleagues reported that injecting bone marrow cells directly into the heart's muscular wall helps restore blood flow, thereby appreciably improving angina symptoms and heart function.

The researchers say that the bone marrow cell therapy can be of particular benefit to patients undergoing treatment for chronic myocardial ischemia - a condition that is marked by long-term, reduced blood flow to specific parts of the heart.

Atsma said bone marrow cells have been found to promote the creation of new blood vessels, thereby restoring blood supply to the heart. Atsma said: "It could be that the cells that are injected become part of the vasculature, the blood vessels. Even better, the injected cells may secrete proteins that stimulate angiogenesis, formation of blood vessels. Or it might be a combination of those two things."

The study observed 50 patients suffering from angina or acute chest pain, and having undergone artery-opening procedures - angioplasty or bypass surgery, with limited benefits - to restore blood flow.

The patients were selected at random for eight bone marrow cell injections. After three months, patients who received the bone marrow cells showed "modest improvements" in blood flow to the heart muscle and in overall heart function.