Washington: Two studies published on Thursday show new ways to fix damaged hearts, one by turning structural heart cells into beating cells and another by restoring a primordial ability to regenerate lost tissue.
The two approaches need more work before they can be tried in humans, but they represent big steps forward in the new field of regenerative medicine.
And they show it may be possible to repair broken organs in the patient`s body, instead of resorting to transplants or artificial devices.
In one study, a team at the Gladstone Institute of Cardiovascular Disease at the University of California, San Francisco made beating heart cells from more ordinary cells called fibroblasts.
Stem cell researchers know they can reprogram these ordinary cells by adding three or four genes to take them back to an embryonic-like state. Teams are working to fine-tune these so-called induced pluripotent stem cells or iPS cells.
Taking this approach a step further, Dr. Masaki Ieda and colleagues found the genes that, in a developing embryo, turn an immature cell into a beating heart cell or cardiomyocyte.
They used these three genes called Gata4, Mef2c, and Tbx5 to convert mouse heart fibroblasts -- which provide structure but which cannot beat -- into the beating cells.
"Scientists have tried for 20 years to convert nonmuscle cells into heart muscle, but it turns out we just needed the right combination of genes at the right dose," Ieda, now at the Keio University School of Medicine in Japan, said in a statement.
When they put these transformed cells into living mice, they converted into beating heart cells within a day, Ieda`s team reported in the journal Cell.