Stem Cells May Help Repair Torn Tendons

A combination of advanced scaffold material and so-called adult stem cells improves the healing of rotator cuff tendon tears over surgery alone, a study in rats suggests.

“As an orthopedic shoulder and knee surgeon and chemical engineer, I think the combination of advanced materials and adult stem cells holds great promise,” Dr. Cato T. Laurencin from University of Connecticut in Farmington told Reuters Health. “For the shoulder, we are looking next to bring this type of technology to clinical use for the treatment of partial thickness and full thickness rotator cuff tendon tears,” he said by email.

Rotator cuff tendon tears are common and often require surgical repair, but most severe tears recur and require additional surgery. Because tendons are made mainly of collagen fibers, with few cells, they have little capacity for regeneration on their own, Laurencin’s team writes in the online journal PLoS ONE.

To see if mimicking the environment in which tendons normally grow would help repaired tendons to heal better than surgery alone, the researchers tested an artificial scaffold embedded with stem cells in a rats with a surgically repaired tendon tear. They compared how well it healed to the same kind of repair in rats that had only the surgery.

The tears repaired with stitches alone continued to show disorganized tissue 12 weeks after surgery, while tendons appeared much more normal after repair using the approach that combines advanced scaffold material with cells to engineer ideal conditions for tissue regeneration.

The addition of stem cells in the matrix, or scaffold, also led to increased mechanical strength and more normal characteristics of the replacement tendon tissue, compared with suturing alone, the study authors note.

The stem cells themselves disappeared over time, suggesting that the therapeutic effect resulted from their release of growth factors or other signaling molecules, rather than from the stem cells turning into tendon.

“We believe they can change the local environment and make it more compatible for regeneration,” Laurencin said. “The stem cells don’t have to become new tissue; they can work by influencing the environment to make better, regenerated tissue. The use of a nanotechnology based matrix is important in making it happen. That’s what this study suggests.”

“We are also developing this type of technology for use in treating problems of the knee,” he noted.

“We believe that the future for tissue regeneration lies in the combination of a number of areas of science and technology: advanced materials science, stem cell science, understanding how physical forces work in regeneration, developmental biology, and clinical translation,” Laurencin said.

“The work presented here combines many elements of regenerative engineering. The real successes will see not just using stem cells alone, but the convergence of different technologies. This new direction in thinking will provide exciting new possibilities for patients in the years to come,” he said.