Researchers have demonstrated some restoration of strength in patients with severe muscle injuries, using scaffold materials derived from the extracellular matrix (ECM) of pig tissues. This is an incremental step forward towards the end goal of complete regeneration, but shows the potential utility of suitable guide materials to spur reconstruction of missing tissues. This has some relevance to the issue of age-related loss of muscle mass and strength; many of the approaches used to regenerate severe muscle injuries may see adaptation to restoration of muscle in the elderly, though for preference not those involving surgical procedures.
For the Muscle Tendon Tissue Unit Repair and Reinforcement Reconstructive Surgery Research Study, 11 men and two women who had lost at least 25 percent of leg or arm muscle volume and function first underwent a customized regimen of physical therapy for four to 16 weeks. Researchers then surgically implanted a "quilt" of compressed ECM sheets designed to fill in their injury sites. Within 48 hours of the operation, the participants resumed physical therapy for up to 24 additional weeks. By six months after implantation, patients showed an average improvement of 37.3 percent in strength and 27.1 percent in range of motion tasks compared with pre-operative performance numbers. CT or MRI imaging also showed an increase in post-operative soft tissue formation in all 13 patients.
The new data builds upon a 2014 study that showed damaged leg muscles grew stronger and showed signs of regeneration in three out of five men whose old injuries were surgically implanted with ECM derived from pig bladder. Those patients also underwent similar pre- and post-operative physical therapy. The recent results included more patients with varying limb injuries; used three different types of pig tissues for ECM bioscaffolds; investigated neurogenic cells as a component of the functional remodeling process; and included CT and MRI imaging to evaluate the remodeled muscle tissue. "The three different types of matrix materials used all worked the same, which is significant because it means this is a generic property of these materials and gives the surgeons a choice for using whichever tissue they like."