Small patches of a protein matrix loaded with stem cells could help to repair the damage caused by a heart attack.

Gordana Vunjak-Novakovic and her colleagues at Columbia University in New York stripped human heart muscle tissue of its cells, leaving behind a porous protein scaffold. They filled this with human mesenchymal progenitor cells, which develop into muscle and other tissues, and then implanted patches of it into the damaged hearts of rat models of heart attack. The patches enhanced the growth of new blood vessels and stopped the left ventricle from enlarging and weakening — common effects of a heart attack.

Instead of forming new vessels or tissues, progenitor cells homed in on the damaged areas and released proteins that stimulated the native tissue to repair itself. Similar patches could deliver other types of cell, such as heart muscle cells created from reprogrammed stem cells, the researchers say.

Proc. Natl Acad. Sci. USA doi:10.1073/pnas.1104619108 (2011)