Tissue Engineers Regenerate Afghanistan Veteran’s Leg Muscle from Pig Bladder Cells

By Rebecca Boyle

Decellularized Hearts A heart is washed of its cells, leaving behind only the structural skeleton that gives the tissue its shape. Courtesy of University of Minnesota

A U.S. Marine whose leg muscles were mostly destroyed in a mortar attack in Afghanistan is reportedly able to walk again after treatment that helped his body re-grow the lost tissue.

Cpl. Isaias Hernandez was 19 when he lost 70 percent of the muscles in his right thigh, and doctors initially recommended amputation, according to a report in the Australian. But Hernandez worked with researchers at the McGowan Institute for Regenerative Medicine at the University of Pittsburgh, who were able to seed his remaining muscles with a cocktail of proteins and growth factors derived from pig bladders, the Australian reports.

Stephen F. Badylak and J. Peter Rubin at Pitt are working with funding from the Defense Department to develop an implantable extracellular matrix that can re-grow tissue. The matrix is a biological scaffold, enriched with proteins and growth factors, which recruits stem cells and other cell precursors to the site of the injury, according to the McGowan Institute’s website. The therapy stimulates further tissue regeneration, essentially rebuilding the lost muscle.

Skeletal muscle does not normally regenerate after an accident, so the ability to re-grow this tissue, complete with nerve branches and tendons, would be a real breakthrough.

We've already seen a similar method used to regenerate bones. Last year, Columbia University researchers were able to grow new joints using abiological scaffold implanted in rabbits. In that case, growth-factor proteins coaxed the rabbits' own stem cells toward the scaffold, where they re-grew bone and cartilage.

Badylak has already reported other tissue engineering advances, notably a re-grown lost fingertip back in 2005, which sparked a media frenzy that later drew criticism. A study on fingertip regeneration using biological scaffolds is still ongoing in Badylak's lab.

The the Australian reports that the biological scaffold treatment allowed Hernandez to regain most of his strength. The newspaper quotes Badylak saying Hernandez had “a remarkable recovery.”

Hernandez was hauling a television to a military vehicle in preparation for an upcoming trip when an enemy mortar exploded, showering him with shrapnel. The TV protected his upper body, but his arms and legs were hit, and his right leg was severely injured.

Before injecting the extracellular matrix, doctors had him perform a rigorous exercise regimen to build up his remaining leg muscle, the Australian reports. Then surgeons made an incision in his thigh and inserted the matrix. After a few weeks, Hernandez’s leg began growing “in bulk and strength,” the Australian says.

The therapy is part of an ongoing study at Pitt, and needs to be tested further — but if it can work on a wider scale, it could prove promising for other warfighters like Hernandez.