Beating Heart Muscle With Built-In Blood Supply Created From Stem Cells

The researchers say the newly engineered muscle could replace cardiac tissue damaged in heart attacks. Their study was published online January 11 in the journal Circulation Research.

According to Professor Shulamit Levenberg of the Technion Biomedical Engineering Department and Professor Lior Gepstein of the Faculty of Medicine, this is the first time that three-dimensional human cardiac tissue complete with blood vessels have been constructed. that may have unique applications for studies of cardiac development, function and tissue replacement therapy.

Despite progress over the past two decades in treating cardiac disease, there are few good ways to fix damaged heart muscle. One possibility would be to rebuild a broken heart with a transplant of healthy heart tissue. However, scientists have been stymied in these efforts by a lack of human heart tissue to work with and the failure of transplanted tissue to thrive in its new home. The heart tissue grown by the Technion researchers is threaded throughout with a network of tiny blood vessels that would improve the tissue’s survival after being transplanted in a human heart, Levenberg says.

The researchers engineered the heart muscle by seeding a sponge-like, three-dimensional plastic scaffold with heart muscle cells and blood vessel cells produced by human embryonic stem cells, along with cells called embryonic fibroblasts. Levenberg’s research team used a similar technique in 2005 to grow skeletal muscle from scratch, and she says the lessons learned from that study helped in designing the heart muscle. For instance, the skeletal muscle study showed that it was important to grow all the different cell types together on the scaffold, and that fibroblasts were key to supporting the blood vessel walls as they developed.

The scientists conducted several tests to make sure the new muscle looked and behaved like heart tissue. Four to six days after being seeded on the scaffold, patches of the new muscle cells began to contract together, a movement that spread until the entire tissue scaffold was beating like normal heart muscle.

The researchers are preparing to transplant the tissue into living hearts in animals to study how well the heart muscle adapts to its new surroundings. Levenberg says that the technique might also prove useful in engineering tissues for other organs such as the liver.