Lisa E. Freed clearly remembers her first successful experiment in engineering heart tissue: the cells she'd "seeded" on a three-dimensional scaffold outside a living body began beating as one.
"It was my most awesome laboratory moment ever. No one had ever done this before," said Dr. Freed, a principal research scientist in the Harvard-MIT Division of Health Sciences and Technology (HST).
That was five years ago. Since then Dr. Freed, Gordana Vunjak-Novakovic (her collaborator then and now) and colleagues from MIT, Harvard Medical School, Boston University, and Brigham and Women's Hospital have been painstakingly studying the engineered cardiac tissue.
Among other things they've characterized the tissues' structural and electrical properties (heart function depends on the ability to conduct electrical impulses), and they've defined key parameters for growing the tissues. Two papers published this month and last report their results.
The work is key to engineering 3D cardiac tissue that could eventually be used to repair damaged heart tissue inside the body, test new drugs, and study general cardiac tissue development and function. Although it could theoretically lead to the creation of an entire heart, the researchers stress that substantial problems must be solved before that could happen.
The MIT approach involves seeding cardiac cells onto a 3D polymer scaffold that slowly biodegrades as the cells develop into a full tissue. The researchers have used the same technique to grow other tissues; in 1996 Drs. Freed and Vunjak-Novakovic with NASA colleagues grew cartilage aboard the Space Station Mir in the first tissue-engineering experiment in space.
The cardiac cells are cultivated on scaffolds five millimeters in diameter by
two thick. The cell/scaffold constructs are placed in a rotating bioreactor that
supplies the cells with nutrients and gases and removes wastes. "The bioreactor
is a kind of microenv
Contact: Elizabeth Thomson
Massachusetts Institute of Technology