Scientists discover how to regenerate damaged heart muscle cells

Claire Tree-Booker

Scientists have uncovered how to turn common heart cells into beating muscle cells.

Around 68 000 people suffer from heart failure annually in the UK, because the heart is unable to repair itself after an attack.

The muscle cells that cause the heart to beat, called cardiac myocytes, die during a heart attack and are replaced by non-beating connective tissue cells, called fibroblasts. This loss of beating muscle cells means that the heart is no longer able to pump as effectively.

Researchers Deepak Srivastava and Masaki Ieda from the Gladstone Institute of Cardiovascular Disease in California investigated whether they could turn fibroblasts into beating cardiac myocytes.

The scientists put several genes known to be important in heart development into mouse cardiac fibroblasts, to see whether they would change into myocytes.

The technique, known as cellular reprogramming, worked successfully and three genes were identified that altered the cells.

After one month of treatment with extra copies of the three genes, known as Gata4, Mef2c and Tbx5, around 20% of the fibroblasts had the characteristics of myocytes, and began to contract like beating heart cells.

In the 6th August issue of Cell, the scientists showed that the reprogrammed cells had proteins on their surface that are normally found in cardiac myocytes, and they expressed similar genes.

The researchers’ next step is to test whether the same genes can be used in human hearts; “I envision such factors being loaded onto a stent that is placed in the coronary artery”, says Professor Srivastava. He believes it is “not unreasonable to imagine being ready for a clinical trial in the next five years”.