Scientists from three countries succeeded in turning human embryonic stem cells into three types of human heart muscle cells.  

A team of Canadian, UK and U.S. scientists has grown three types of human heart cells from cultures derived from embryonic stem cells. The three cell types created – cardiomyocytes, endothelial cells and vascular smooth muscle cells – are each important constituents of heart muscle.  

When the scientists transplanted the three types into mice with simulated heart disease, their heart function was improved, offering hope to researchers who may want to develop this technique for treating human hearts.

“We’re not the first group to show that you can make heart cells from embryonic stem cells. That’s been done before. So what’s different here? We’ve taken more of a step-wise approach to following the progression of how these embryonic stem cells move through development to make the first type of heart cells,” Gordon Keller of the McEwen Centre for Regenerative Medicine in Toronto, who led the research, said in a telephone interview with Reuters.

Following this discovery, the researchers may be able to use the cells to make artificial heart tissue, which could then be transplanted into an actual human heart.

"It's not clear how effective injecting cells directly into the heart ever will be. A huge advantage we have is that these unique progenitor cells can make three of the major types of cells in the heart, so we hope we can simply seed these progenitor cells onto scaffolding and make what might be an artificial piece of heart tissue and possibly transplanting such small pieces of tissue, and engrafting them into the heart, would be more effective than transplanting the cells themselves,” Keller said.

He also added that tests in larger animals, such as pigs and sheep, would be necessary before considering testing them on patients. The scientists are hopeful that human testing can begin within three years.

“In the future, these cells may also be very effective in developing new strategies for repairing damaged hearts, following a heart attack,” the scientists said.

The study’s findings appeared in the journal Nature on Wednesday.