A microscopic view of lab-grown human muscle bundles stained to show patterns made by basic muscle units and their associated proteins (red), which are a hallmark of human muscle.
Laboratory work to grow real muscle tissue has yielded some promising results, but we haven’t seen true muscles created that contract in response to an electrical signals. Now researchers at Duke University have reported the development of just such human skeletal muscle that works much like the real thing. Though the hope is certainly of using this technology in rebuilding cardiac and other muscle tissues, the technique will find the most benefit in research applications studying how muscles are influenced by different therapies.
Two lab-grown human muscle bundles stretched in a rectangular frame submerged in a medium.
The team used myogenic precursors, cells that exited the stem stage, but have not yet turned into their final tissue type. They bred these more than 1,000 fold and deposited them into a 3D matrix which was filled with a nutrient gel and allowed to form into a functional muscle fiber structure. The tissue had functional nerve signaling pathways and responded to electrical stimuli. Moreover, chemical stimuli in the form of pharmaceutical drugs were delivered to see how the tissue responds compared to real muscles. The results showed a very high correlation, pointing toward this technology to be used to displace clinical trials on human subjects.
From the study abstract in open access journal eLife:
These biomimetic constructs exhibit aligned architecture, multinucleated and striated myofibers, and a Pax7+ cell pool. They contract spontaneously and respond to electrical stimuli with twitch and tetanic contractions. Positive correlation between contractile force and GCaMP6-reported calcium responses enables non-invasive tracking of myobundle function and drug response. During culture, myobundles maintain functional acetylcholine receptors and structurally and functionally mature, evidenced by increased myofiber diameter and improved calcium handling and contractile strength. In response to diversely acting drugs, myobundles undergo dose-dependent hypertrophy or toxic myopathy similar to clinical outcomes. Human myobundles provide an enabling platform for predictive drug and toxicology screening and development of novel therapeutics for muscle-related disorders.
Study in journal eLife: Bioengineered human myobundles mimic clinical responses of skeletal muscle to drugs…
