http://www.npr.org/blogs/health/2014/04/30/308395528/experimental-t...

.....So Badylak decided to try surgically transplanting a quilt of matrix cells derived from pig bladders into the legs of patients whose muscles had been partially destroyed. He started with five patients — Strang and four other men who were disabled despite the best physical therapy and the best that medicine had to offer.

Before the experimental treatment, "some of them could not get out of a chair without help," Badylak says. "Some of them walked with a cane. ... This was not just a mild loss of strength. They had real problems."

Strang was initially skeptical. "It kind of seemed far-fetched," he says. But he decided to give it a try. And, just as Badylak had hoped, the pig matrix triggered immature muscle cells that had been dormant in the men's bodies to grow — and to make new, healthy muscle rather than scar tissue.