Lead researcher Dr. Shulamit Levenberg of the Technion-Israel Institute of Technology, along with scientists from the Massachusetts Institute of Technology, grew the muscle from scratch by seeding a sponge-like, three-dimensional plastic scaffold with myoblasts and endothelial cells, which are the precursors to mature skeletal muscle and blood vessel cells. The researchers also added connective tissue cells called fibroblasts to the mix as a crucial third ingredient.
"The idea is that this hopefully will be used to repair or replace damaged muscle tissue when needed," Levenberg says.
In the near future, Levenberg explains, a simple muscle biopsy might provide the "seed" cells for a person's own engineered replacement muscle. For example, the lab-grown muscles could replace tissue lost to severe trauma such as burns, or build up muscle that has weakened or wasted away in diseases like AIDS.
Until now, most scientists have not attempted to provide engineered tissue with its own blood supply. Instead, they have implanted the new tissue into the body and waited for the body itself to infiltrate the tissue with blood vessels.
"Although this approach has been useful in many tissues, it has not been as successful in thick, highly vascularized tissues such as the muscle," Levenberg says.
To create muscle tissue that would be threaded through with blood vessels before being implanted, the researchers mixed different cell types together on the plastic mold for the tissue. The different cells quickly organized themselves on the scaffold, with the myoblast cells transforming into aligned and elongated muscle fiber tubes and the endothelial cell