Sergeant Ronald Strang survived an IED blast in Afghanistan that shredded muscle from his left leg. After 18 months and 14 surgeries, his movement was still very limited. So he entered a Pitt-UPMC study that would test a new approach to significant muscle loss. Researchers began with some physical tests. For instance, Strang was asked to jump as far as possible while standing on his left leg, where his quadriceps had lost 68 percent of muscle tissue. The best he could do was hop about an inch.
Then, Strang underwent a groundbreaking surgery that used tissue scaffolding created from a pig’s bladder to spur new muscle growth. Six months later, he was asked to jump again, using only his wounded left leg. This time, he was able to leap 24 inches.
Strang was one of five men who took part in this study, supported with funds from the U.S. Department of Defense and conducted by the McGowan Institute for Regenerative Medicine, a Pitt and UPMC program. Stephen Badylak, deputy director of the McGowan Institute, and J. Peter Rubin, chair of the Department of Plastic Surgery, led a team of researchers on the study. The results were published in 2014 in Science Translational Medicine.
This was the first study ever to regenerate muscle in humans by applying ECMs, although researchers have previously used ECMs to repair urinary bladders, hernias, and esophageal lining. The scientific principles are the same, no matter the body part, Badylak explains. These cell-free scaffolds look like a translucent sheet. When placed in a patient’s body, they recruit the patient’s own stem cells and alter the function of “inflammatory” cells so that they all aid in the regeneration of healthy tissue, he says....
Damaged leg muscles grew stronger and showed signs of regeneration in three out of five men whose old injuries were surgically implanted with material derived from a pig bladder, according to a new study conducted by researchers at the University of Pittsburgh School of Medicine and the McGowan Institute for Regenerative Medicine. Early findings from a human trial of the process and from animal studies were published recently in Science Translational Medicine.
“This new study is the first to show replacement of new functional muscle tissue in humans, and we’re very excited by its potential,” senior investigator Stephen F. Badylak said. “These are patients who can’t walk anymore, can’t get out of a car, can’t get up and down from a chair, can’t take steps without falling. Now we might have a way of helping them get better.”
When a large volume of muscle is lost, typically due to trauma, the body cannot sufficiently respond to replace it, explained Badylak, a Pitt professor of surgery and deputy director of the McGowan Institute, a joint effort of Pitt and UPMC. Instead, scar tissue can form, significantly impairing the muscle’s strength and function.
The pig bladder material, known as the extracellular matrix, is the non-cellular biologic scaffold that remains after cells have been removed from the pig bladder. For many years, the material has served as the base for medical products used to repair hernias and treat skin ulcers. Earlier research by Badylak’s team suggested that the extracellular matrix also could be used to regenerate lost muscle by placing the material in the injury site. Once there, it signals the body to recruit stem and other progenitor cells to rebuild healthy tissue....