Study shows how scar tissue can be turned into healthy heart muscle

Sept. 26 (UPI) -- Researchers from the University of North Carolina Chapel Hill have found ways to reprogram scar tissue cells into healthy heart muscle cells.

A major challenge for doctors is that the heart is unable to regenerate healthy cells, known as cardiomyocytes, after a heart attack, so muscles damaged after heart attacks stay damaged.

UNC School of Medicine researchers compared two leading reprogramming techniques, finding that one method leads to the creation of cardiomyocytes with genetic signatures that mimic those found in healthy adult heart muscle cells.

The study, published today in Cell Reports, also found that the other method of reprogramming leads to the creation of cardiomyocytes with more embryonic cell signatures.

The first method involves an adult connective cell, called a fibroblast, which is reprogrammed into a naive embryonic stem cell-like state. In this naive state, the cell has the potential to develop into any cell type in the body -- with researchers directing them to develop into cardiomyocytes. The new cardiomyocytes are known as induced pluripotent stem cell cardiomyocytes, or IPSC-CM.

The second method, called direct cardiac reprogramming, involves a fibroblast being directly converted into a cardiomyocyte without having to first be reprogrammed into a naive embryonic stem cell. These types of new cardiomyocytes are known as induced cardiomyocytes, or ICM.

"The differences in the cardiomyocytes generated using these two methods are striking," Li Qian, assistant professor of pathology and laboratory medicine at UNC, said in a press release. "Researchers can choose one or the other method based on the specific type of cardiac disease they are interested in studying, while clinicians could carefully select which method is best, considering the pros and cons of each approach."

Researchers found that both methods resulted in cells with classic cardiomyocyte molecular features, but by comparing the unique set of genes activated or not activated in each cell group, the IPSC-CMs more closely resembled embryonic cardiomyocytes and ICMs more closely resembled adult cardiomyocytes.

"This is crucial knowledge," Qian said. "When developing research projects or creating new therapies, we need to know these sorts of genetic features to best help patients. Although each method has pros and cons, for congenital heart disease, iPSC-CMs might be ideal for the study of mechanism and for performing drug screens."