Mending the Broken Heart

A team of biomedical engineers from the University of Michigan have been successful in turning common cells found in scar tissue into the colonies of heart beating cells. Damaged or scarred heart cannot beat efficiently like a normal heart, but reprogramming cells can make it work like a normal one. Previous attempts in reprogramming scarred cells were less successful as scientists felt that the environment of the cells was not taken into consideration.

The new study, however, chose to figure out how cells’ surroundings can improve the efficiency of reprogramming. For this, Yen Peng Kong, a post doctoral researcher attempted to turn the scarring cells or fibroblasts into heart muscle cells by letting them grow in gels of varying stiffness. He and his team then compared a soft commercial gel with medium–stiffness fibrin and high–stiffness collagen made of structural proteins. The conversion of fibroblast taken from mouse embryos to heart muscle cells began by infecting the fibroblasts with a specially designed virus that carried mouse transgenes (genes expressed by stem cells). This way the cells were fooled into the stem cell behaviour and the fibroblasts turned into stem–like cells known as progenitor cells. The skipping of this step led to failures in the earlier methods.

After seven days, a protein that aids the heart tissue was added to the mixture. This helped the cells in adopting heart muscles’ activity. The transition from fibroblasts to heart muscles was particularly successful in fibrin and fibrin collagen mixtures where more than half of the colonies transformed into a heart muscle.