Harvard Heart Letter

Stem cells to repair heart damage? Not so fast

Dozens of clinics offer unproven stem cell therapies for heart failure. Despite steady progress, this experimental treatment is not ready for prime time.

A heart attack cuts off blood flow to part of the heart’s muscle, usually causing lasting damage. Over time — especially in people with repeat heart attacks — the resulting scar tissue can hinder the heart’s ability to function normally, leading to heart failure.

For nearly two decades, scientists have studied how stem cells might repair a damaged heart and restore its function. These unique cells, which have the potential to grow into a variety of heart cell types, can be made from other cells (see “What’s new in cardiac regeneration?”).

What’s new in cardiac regeneration?

Researchers who study ways to repair damaged heart tissue use several types of cells, but most focus on cardiomyocytes, the beating muscle cells found in the chambers of the heart.

Although scientists can grow cardiomyocytes in the lab from embryonic stem cells, there’s also growing enthusiasm to instead use cells from the heart itself, says Dr. Lee. Getting the heart to repair itself may sound like science fiction, but many animals can do it. Researchers are also exploring new ways to transplant laboratory-generated heart cells back to the heart, such as using bioengineered tissue patches instead of injections or infusions.

Unregulated clinics

More than 100 clinical trials have shown that delivering stem cells to the heart is feasible and safe. But so far, there is no clear, consistent evidence of a noticeable improvement in people with heart disease who receive stem cells. Yet 61 centers throughout the United States market stem cell therapies for people with heart failure, according to a research letter in the Sept. 1, 2017, JAMA Internal Medicine. These clinics charge an average of $7,694 for a single treatment of autologous stem cells (taken from a person’s own body). Only nine centers required copies of the patient’s medical records, and only one facility listed a board-certified cardiologist on staff.

“I get emails almost daily from people wanting advice about where they can get a stem cell treatment for their heart,” says Harvard Medical School professor Dr. Richard Lee of Brigham and Women’s Hospital and the Harvard Stem Cell Institute. He warns strongly against clinics that operate outside of major academic medical centers. Unregulated clinics have come under fire from the FDA; the agency has shut down several clinics and issued warning letters to others. “These clinics are selling something with unproven value and unknown hazards,” says Dr. Lee.

In 2016, The New England Journal of Medicine reported a case study of a 66-year-old stroke survivor who received stem cell injections into his spine at clinics in China, Argentina, and Mexico. He developed a spinal tumor that left him in pain, partially paralyzed, and incontinent. Unregulated stem cell clinics are not only potentially dangerous, they also undermine attempts to study stem cell therapies in clinical trials, according to the report’s authors, all of whom are physicians at Brigham and Women’s Hospital.

What you can do now

Dr. Lee gives the same advice to everyone who contacts him about stem cell treatments: if you have heart failure, you should receive treatment in a tertiary care heart failure center that sees a lot of patients. (Tertiary care centers feature specialists in large hospital settings.) These centers provide the latest drug treatments at the correct dosage, says Dr. Lee. He finds that patients treated outside of heart failure centers don’t always get the optimal doses of the most effective heart failure medications.

If you’re interested in participating in a study of stem cell therapy, visit the National Institute of Health’s listing at clinicaltrials.gov and search for studies in your area (for example, search “stem cells,” “heart failure,” and “Chicago”). When you participate in a study performed at a state-of-the-art heart center, even if you end up in the placebo arm of a study (meaning that you’re getting standard therapy instead of the experimental treatment), you’ll still receive first-rate care. These studies also carefully monitor patients’ well-being and safety.

“Everyone would like to see a stem cell therapy for heart failure, but that’s going to be many years from now. In the meantime, make sure your heart failure care is first-rate,” says Dr. Lee, who is a former co-editor in chief of the Harvard Heart Letter.

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