Even though medical advances have made it possible for people who suffer from heart attacks or other serious forms of heart disease to live longer than ever before, these patients face a lifetime of tests, daily medications and frequent doctor visits to keep their hearts working and to prevent subsequent damage.
But what if it were possible to go a step further—to actually replace damaged heart tissue with new, fully functioning cells…in essence, to rebuild a healthy heart? It sounds like science fiction, but the advances being made are promising. In laboratories and hospitals around the world, heart researchers are making remarkable strides in developing stem cell therapy for serious heart conditions.
A groundbreaking study: In research published in The Lancet, patients with heart scarring from previous heart attacks were given stem cells in their coronary arteries that were extracted from healthy tissue in their own hearts. Within 12 months, the amount of scar tissue was reduced by about 50%. (Patients in a control group given standard treatments had no improvement.)
Here’s what you need to know about the exciting possibilities—and challenges—for the use of stem cell therapy in heart patients…
So how exactly does stem cell therapy work? Think of stem cells as the key “blanks” that hardware stores use to copy a key. These blanks all look the same until the edges are cut and polished. Once a key is cut, it will open only a particular lock.
Stem cells are like key blanks (except that they also have the ability to divide and create exact copies of themselves). They’re undifferentiated cells that can eventually turn into specialized, functioning cells.
While embryonic stem cells, which exist only briefly at the earliest stages of human development, can be developed in the lab, the stem cells that are used in today’s treatments are usually taken from a donor’s blood or bone marrow or from the patient’s own bone marrow or heart—a process that usually involves an outpatient aspiration procedure.
Heart failure, the ineffective pumping of the heart that is usually caused by a heart attack, coronary artery disease or high blood pressure, has been a main focus of stem cell therapy. Nearly 5 million Americans have it, and more than half will die within five years after being diagnosed. No current treatments can repair damaged heart-muscle cells.
New approach: Patients with heart failure can be infused (often via a catheter that’s threaded through the coronary artery into the damaged area of the heart) with millions of stem cells. The onetime treatment can potentially regenerate healthy heart cells. In theory, this approach could completely reverse heart failure—but the research is still in the early stages. Among the important findings…
• In animal studies conducted at Johns Hopkins University and Cedars-Sinai Medical Center, stem cells from the injured hearts of animals were extracted and cultured in a laboratory, then reinjected back into animals’ damaged hearts. They quickly began to form new heart and blood vessel cells. Treated animals had about a 25% reduction in the size of damaged areas, or infarcts.
• The landmark BOOST study, led by German researchers at Hannover Medical School randomly assigned 60 patients with heart damage to receive either standard treatments or an infusion of autologous (their own) bone marrow stem cells. Six months later, patients given the stem cells showed an increase in left-ventricular ejection fraction (a measure of the heart’s pumping ability) of 6.7%. In the control group, the improvement was just 0.7%.
While these and other studies are promising, overall results have been mixed. A large study conducted at Jamia Hamdard University in India, for example, found that heart attack patients given stem cell therapy showed no measurable increase in heart strength.
If you’re a heart patient, don’t expect your doctor to recommend stem cell therapy. It’s an exciting development because we now know that it’s possible to repair heart damage, but important questions remain.
Will the “replacement” cells function indefinitely? Will the results from animal studies apply to humans? Are stem cells derived from heart tissue more effective than those extracted from bone marrow?
Caution: Some cardiologists in the Bahamas and elsewhere have begun offering stem cell therapy for heart patients. At this time, however, there’s more we need to know before stem cell therapy is ready for prime time—and the procedures aren’t risk free.
Some early studies have found that stem cell treatments might cause an increase in heartbeat irregularities. Experts are also concerned that there might be an increase in atherosclerosis. One way to minimize these potential complications is to enroll in a formal study with careful observation.
If you’ve had a heart attack or been diagnosed with heart failure, you might want to participate in a clinical trial looking at stem cell therapy. To find a study in your area, go to ClinicalTrials.gov. In the search box, type in your city and the type of study you’re looking for (for example, “New York,” “heart failure” and “stem cells”).
Important: Don’t rule out such a study because you assume that there is always a placebo group. Some studies don’t use placebos (everyone gets different forms of the new treatment), and other trials provide the best available standard treatment to those who don’t receive the treatment being studied. You’ll also get extensive and careful monitoring in either case. Ask your doctor for advice.