By Jeni Baker

Imagine a patch -- made of fully functional cardiac tissue -- that could safely and effectively restore function to heart muscle injured by a heart attack or plagued by an arrhythmia.

This is the work of Duke biomedical engineer Nenad Bursac, PhD, and his team in the Cardiac Electrophysiology and Tissue Engineering (CETE) lab. They’re using undifferentiated stem cells to build functioning patches of heart tissue that can directly replace damaged or malfunctioning heart-muscle cells (cardiomyocytes).

The work offers a different approach than injecting stem cells into hearts, which is another experimental technique to achieve the same goal.

Bursac notes that injected cells frequently can’t be placed in the optimal location, and they often don’t survive or function correctly. A patch, however, can place the needed tissue in the best location, optimizing the likelihood of cell integration and survival.

“It helps to go in with a defined tissue structure,” Bursac says. “So while implanting a cardiac patch is more invasive surgically than injecting cells into the heart, it will hopefully be more functional.”

The federally funded CETE lab -- a component of the Pratt School of Engineering’s Biomedical Engineering program -- is investigating the structural and functional interactions among implanted heart muscle cells and other cells.

“We’re trying to see how well these cells connect with the myocardium and contract with the rest of the heart,” Bursac says. The goal is for these cells to integrate well enough with existing heart tissue that they will be electrically and mechanically in sync -- contracting and conducting signals as if they were part of the heart.

A recent study of experimental patches using embryonic stem cells from mice -- now submitted for publication -- shows the current models to be “working beautifully,” Bursac says.

Duke cardiologists Howard Rockman, MD, and Lan Mao, MD, who implant the patches in mice and rats in Rockman’s laboratory, believe the patches have the potential to be of great benefit to people with cardiac damage and disease.