Mending broken hearts
Assistant Professor, University of Toronto Institute of Biomaterials and Biomedical Engineering, and Department of Chemical Engineering and Applied Chemistry. Age: 33
One night while working in a lab at the Massachusetts Institute of Technology, grad student Milica Radisic saw how “beautifully and perfectly” an individual cardiomyocyte was pulsating when she applied an electrical stimulus from a platinum electrode. She wondered if applying this same electrical impulse to multiple cells would cause them to beat together, simulating the contractions of an intact heart.
Long before this thought occurred to her, Radisic read an article about human tissue engineering by Robert Langer, while studying chemical engineering as an undergrad at McMaster University in Ontario.
“When I read that article I got totally excited,” Radisic says. “I wanted to do something that benefitted human health.” Radisic sent a letter to Langer, who she didn’t realize was the “father of tissue engineering,” asking him to consider her application to work in his lab at the Massachusetts Institute of Technology.
METHODS: After being accepted into Langer’s lab in 1999, Radisic began working on engineering functional cardiac tissues using rat stem cells.
Radisic and her colleagues developed a scaffold of engineered cardiac tissue and designed a system to maintain oxygen supplies to the stem cells during seeding, key for maintaining cell viability and function in a regenerating heart.1
Radisic then applied electrical field stimulations to the cultured rat heart cells. After 8 days of this, the cells aligned and coupled, displaying the rhythmic beating of mature cardiac tissue, and creating a model that could be used for biomedical research.2 Radisic obtained a patent for her electrically stimulated “heart patch” in 2005.
RESULTS: In 2005, Radisic joined the faculty of the University of Toronto, where she continues to develop her heart patch. “We are using the same principles, to make tissue out of cardiomycotes from human embryonic stem cells,” says Radisic.
She is now studying the patch’s ability to test new drugs and cell lines.3 Peter Zandstra, a stem cell bioengineer and colleague at University of Toronto, says that using the patch to test the potential of embryonic stem cells for tissue repair is proving more useful than in vivo experiments. By using Radisic’s patches, he says, there is a more controlled environment to see the “integration between the test cells and her engineered environment.”
DISCUSSION: Langer says that Radisic was “innovative and had many creative ideas even as a graduate student.” Zandstra adds that her innovative qualities make Radisic a “great collaborator and fun to work with.”
Her colleagues also marvel at how Radisic has managed all of her scientific achievements while raising a young family. She has three young children and had her first while still a PhD student. Langer says that he was amazed by how Radisic was “unphased” throughout grad school, keeping up her rigorous lab work even while pregnant. Life is “very intense in the lab and at home, but both of these aspects help each other,” Radisic says.
|Literature Cited |
1. M. Radisic et al., “Medium perfusion enables engineering of compact and contractile cardiac tissue,” Am J Physiol Heart Circ Physiol, 286:507–16, 2004 (cited in 58 papers)
2. M. Radisic et al., “Functional assembly of engineered myocardium by electrical stimulation of cardiac myocytes cultured on scaffolds,” PNAS, 101:18129–34, 2004 (cited in 106 papers)
3. H. Song et al., “Interrogating functional integration between injected pluripotent stem cell-derived cells and surrogate cardiac tissue,” PNAS, 107:3329–34, 2010 (cited in 1 paper)