Chronic ischemic heart disease results from the partial blockage of blood flow to the heart. It can result in damage to the heart, and symptoms that consist of shooting pain in the chest called “angina.” Fortunately, there are good, animal models of chronic ischemic heart disease and better ways to treat this disease are being investigated. A presentation at the American Heart Association annual meeting has shown that new heart cells can be produced in animals that have been given infusions of stem cells derived from cardiac biopsies or “cardiospheres.”
Research conducted at the University at Buffalo School of Medicine and Biomedical Sciences has demonstrated that the hearts of animals with chronic ischemic heart disease experience a 30 percent increase in healthy heart muscle cells within one month after receiving cardiosphere-derived cells (or CDCs). This finding is contradicts conventional medical wisdom which avers that heart cells are terminally differentiated and thus, are unable to divide.
Ischemic heart disease results from narrowing of coronary arteries and prior heart attacks are the most common cause of heart failure. Other investigators have largely focused on regenerating muscle in scarred tissue, but this UB group has shown that cardiac repair can be achieved by infusing CDCs slowly into coronary arteries of the diseased as well as normal areas of the heart. Study co-author John M. Canty Jr., MD, the Albert and Elizabeth Rekate Professor of Medicine in the UB medical school and UB’s chief of cardiovascular medicine explains: “Whereas most research has focused upon irreversible damage and scarring following a heart attack, we have shown that a single CDC infusion is capable of improving heart function in areas of the heart that are viable but not functioning normally.” Particular areas of heart dysfunction even their there is no fibrotic scarring are common in patients with heart failure from coronary artery disease. Heart failure results from “remodeling” in response to a heart attack, in which the heart enlarges to adjust to the loss of heart muscle. Another consequence of a heart attack and periods of inadequate blood flow to the heart muscle is so-called hibernating myocardium, in which segments of heart muscle exhibit abnormalities of contractile function. Canty commented further: “The rationale for our approach is somewhat analogous to planting seeds in fertile soil versus trying to grow plants in sand.
Gen Suzuki, MD, research assistant professor of medicine in the UB medical school and lead author on the research, noted: “We have shown that cells derived from heart biopsies can be expanded outside of the body and slowly infused back into the coronary arteries of animals with chronic dysfunction from restricted blood flow or hibernating myocardium. The new cardiac muscle cells are small and function more normally than diseased large, hypertrophied myocytes.”
Canty also noted that infusing stem cell formulations directly into coronary arteries also delivers the cells throughout the heart and is much simpler than injecting cells directly into heart muscle which requires equipment that is not widely available.
The research currently is in a preclinical phase but the UB researchers expect that translation to determine effectiveness in patients could take place within two to three years or possibly even sooner.