Imagine lab-grown living muscle that contracts, integrates and has the ability to heal itself both inside the laboratory and inside an animal.
In a first, researchers have engineered such strong skeletal muscle that heals itself after animal implantation.
The study conducted at Duke University tested the bioengineered muscle by literally watching it through a window on the back of living mouse.
The novel technique allowed for real-time monitoring of the muscle's integration and maturation inside a living, walking animal.
"Both the lab-grown muscle and experimental techniques are important steps toward growing viable muscle for studying diseases and treating injuries," said Nenad Bursac, an associate professor of biomedical engineering at Duke University.
It is the first time engineered muscle has been created that contracts as strongly as native neo-natal skeletal muscle.
The team led by Bursac and graduate student Mark Juhas discovered that preparing better muscle requires two things - well-developed contractile muscle fibres and a pool of muscle stem cells known as satellite cells.
Every muscle has satellite cells on reserve, ready to activate upon injury and begin the regeneration process.
The key to the team's success was successfully creating the microenvironments - called niches - where these stem cells await their call to duty.
"The well-developed muscle we made provides niches for satellite cells to live in, and, when needed, to restore the robust musculature and its function," Juhas said.
The team inserted their lab-grown muscle into a small chamber placed on the backs of live mice.
The chamber was then covered by a glass panel.
Every two days for two weeks, Juhas imaged the implanted muscles through the window to check on their progress.
"We could see and measure in real time how blood vessels grew into the implanted muscle fibres, maturing toward equaling the strength of its native counterpart," Juhas noted.
The engineers are now looking if such muscle can be used to repair actual muscle injuries and disease.
The results appeared in the journal Proceedings of the National Academy of Sciences.
