Professor Shulamit Levenberg of the Technion Biomedical Engineering Department and Professor Lior Gepstein of the Faculty of Medicine, said this is the first time that 3-dimensional human cardiac tissue complete with blood vessels have been constructed. This may actually have unique applications for studies of cardiac development, function and tissue replacement therapy.

The heart tissue is threaded throughout with a network of tiny blood vessels that would improve the tissue’s survival after being transplanted in a human heart.

The heart muscle was engineered by seeding a sponge-like, 3-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 example, 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.

4 to 6 days after being seeded on the scaffold, patches of the new heart 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.