The team, which was led by Gordon Keller at the University Health Network’s McEwen Centre for Regenerative Medicine in Toronto, developed a way of maturing embryonic stem cells into early heart cells and purifying them. They did this by first discovering a protien that's on the surface of early heart cells. They could then use antibodies to keep only those cells that have the protein and eliminate all cells without the protein. Creating pure populations of cells is critical for developig therapies, which need to be free of the original embryonic stem cells that can form tumors.
A press release from VistaGen described the technology:
These findings provide, for the first time, a simple method for isolating some of the earliest populations of cardiac precursors and mature cardiomyocytes from human pluripotent stem cell cultures. This readily adaptable technology offers a viable approach for generating large numbers of enriched, non-genetically modified, cardiomyocytes for numerous therapeutic applications.Creating pure populations of cells is just the first step. Before the cells are shown to be therapeutically useful they must be able to integrate into the complex three-dimensional structure of the human heart and beat in time with the surrounding tissue.