Stem cells from strangers can help fix hearts, study finds

LOS ANGELES — Researchers are reporting a key advance in using stem cells to repair hearts damaged by heart attacks.

In a study, stem cells donated by strangers proved as safe and effective as patients’ own cells for helping restore heart tissue.

The work involved just 30 patients in Miami and Baltimore, but it proves the concept that anyone’s cells can be used to treat such cases. Doctors are excited because this suggests that stem cells could be banked for off-the-shelf use after heart attacks, just as blood is kept on hand now.

Results were discussed Monday at an American Heart Association conference in California and published in the Journal of the American Medical Association.

The study used a specific type of stem cells from bone marrow that researchers believed would not be rejected by recipients. Unlike other cells, these lack a key feature on their surface that makes the immune system see them as foreign tissue and attack them, explained the study’s leader, Dr. Joshua Hare of the University of Miami.

The patients in the study had suffered heart attacks years earlier, some as long as 30 years ago. All had developed heart failure because the scar tissue from the heart attack had weakened their hearts so much that they grew large and flabby, unable to pump blood effectively.

Researchers advertised for people to supply marrow, which is removed using a needle into a hip bone. The cells were taken from the marrow and amplified for about a month in a lab at Baltimore’s Johns Hopkins University, then returned to Miami to be used for treatment, which did not involve surgery.

The cells were delivered through a tube pushed through a groin artery into the heart near the scarred area. Fifteen patients were given cells from their own marrow and 15 others, cells from strangers.

About a year later, scar tissue had been reduced by about one-third.