A car accident leaves an aging patient with severe muscle injuries that won’t heal. Treatment with muscle stem cells from a donor might restore damaged tissue, but doctors are unable to deliver them effectively. A new method may help change this.

Researchers at the Georgia Institute of Technology engineered a molecular matrix, a hydrogel, to deliver muscle stem cells called muscle satellite cells (MuSCs) directly to injured muscle tissue in patients whose muscles don’t regenerate well. In lab experiments on mice, the hydrogel successfully delivered MuSCs to injured, aged muscle tissue and boosted the healing process while protecting the stem cells from harsh immune reactions.

The method was also successful in mice with a muscle tissue deficiency that emulated Duchene muscular dystrophy, and if research progresses, the new hydrogel therapy could one day save the lives of people suffering from the disease.

Inflammation war zone

Simply injecting additional MuSCs into damaged, inflamed tissue has proven inefficient, in part because the stem cells encounter an immune system on the warpath.

“Any muscle injury is going to attract immune cells. Typically, this would help muscle stem cells repair damage. But in aged or dystrophic muscles, immune cells lead to the release a lot of toxic chemicals like cytokines and free radicals that kill the new stem cells,” said Young Jang, an assistant professor in Georgia Tech’s School of Biological Sciences and one of the study’s principal investigators.

Only between 1% and 20% of injected MuSCs make it to damaged tissue, and those that do, arrive there weakened. Also, some tissue damage makes any injection unfeasible, thus the need for new delivery strategies.

“Our new hydrogel protects the stem cells, which multiply and thrive inside the matrix. The gel is applied to injured muscle, and the cells engraft onto the tissues and help them heal,” said Woojin Han, a postdoctoral researcher in Georgia Tech’s School of Mechanical Engineering and the paper’s first author.

Han, Jang, and Andres Garcia, the study’s other principal investigator, published their results on August 15, 2018, in the journal Science Advances. The National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health funded the research.

—Newswise