Stem cells from the bone marrow of healthy donors are better and safe for treating damaged hearts than cells taken from patients own tissue, report scientists.
The 13-month trial by researchers from the University of Miami Miller School of Medicine, funded by the National Institutes of Health, involved 30 patients and was the first to compare the safety and effectiveness of mesenchymal stem cells derived from bone marrow of patients themselves as against those provided by donors.
The study suggests that stem cells could be banked for off-the-shelf use after heart attacks, just as blood is kept on hand now.
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 attacks them, said 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.
Researchers advertised for people to supply marrow. The cells were removed from the marrow using a needle into the hip and then 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 Daily Express reported.
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 a third. Both groups had improvements in how far they could walk and in quality of life.
The big attraction was the benefit of using cells supplied by others, with no blood or tissue matching needed.
The study has been published in the Journal of the American Medical Association.