An interesting, and possibly ground breaking, study was published recently in Nature Communications by biomedical engineering researchers at Duke University. In the study, Lingjun Rao Ph.D. and colleagues were able to demonstrate the ability to create functioning human muscle cells out of non-muscle stem cells. The implications could be extraordinary for diseases such as the muscular dystrophies.

Previously, the Duke researchers, led by Nenad Bursac, professor of biomedical engineering showed they could create functional muscle cells from cells obtained in a muscle biopsy but the new study means that theoretically, they could take skin or blood cells from a person with Duchenne muscular dystrophy and using genetic engineering, grow muscle cells that could then be inserted into the same person’s muscle tissue.

At least in theory.

For now, the researchers were able to show that they could create functioning muscle cells from human stem cells and when they implanted the muscle bundles into the hindlimb muscle of mice, the bundles were able to survive, become vascularized, and maintain their functionality.

In a news release, Dr. Rao confessed this study was a long time coming. “It’s taken years of trial and error, making educated guesses and taking baby steps to finally produce functioning human muscle from pluripotent stem cells” The key to the success of the study was created a 3-dimensional matrix for the cells to grow in. Dr Rao said, “What made the difference are our unique cell culture conditions and 3-D matrix, which allowed cells to grow and develop much faster and longer than the 2-D culture approaches that are more typically used.”

The ability to use non-muscle cells instead of muscle cells in a patient with a degenerative muscle disease is especially appealing to the researchers. Dr Bursac noted, “When a child’s muscles are already withering away from something like Duchenne muscular dystrophy, it would not be ethical to take muscle samples from them and do further damage. But with this technique, we can just take a small sample of non-muscle tissue, like skin or blood, revert the obtained cells to a pluripotent state, and eventually grow an endless amount of functioning muscle fibers to test.”

The researchers in Dr. Bursac are continuing to fine tune the methodology with the hope to grow more robust muscles and begin working on developing new models of rare muscle diseases.

Reference

Rao L, Qian Y, Khobadukus A, Ribar T, Bursac N. Engineering Human Pluripotent Stem Cells into a Functional Skeletal Muscle Tissue. Nature Comm, Jan 9, 2018. DOI: 10.1038/s41467-017-02636-4. Available at www.nature.com/articles/s41467-017-02636-4. Accessed Jan 10, 2018.

Image from Duke University news release showing a stained cross section of the new muscle fibers. The red cells are muscle cells, the green areas are receptors for neuronal input, and the blue patches are cell nuclei.