The feasibility of treating spinal pain by replacing deteriorating discs with those made from “engineered living tissue” has been demonstrated in an animal study published recently in Science Translational Medicine.
The study, which was performed on goats, was conducted by a team of scientists in the University of Pennsylvania’s Perelman School of Medicine, School of Engineering and Applied Science, and School of Veterinary Medicine.
“This is a major step: to grow such a large disc in the lab, to get it into the disc space, and then to have it to start integrating with the surrounding native tissue. That’s very promising,” says Robert L. Mauck, PhD, a professor for Education and Research in Orthopaedic Surgery in Penn’s Perelman School of Medicine and a Research Health Scientist at the Corporal Michael Crescenz VA Medical Center (CMC VAMC) in Philadelphia, and co-senior author of the paper, in a media release from Perelman School of Medicine at the University of Pennsylvania.
“The current standard of care does not actually restore the disc, so our hope with this engineered device is to replace it in a biological, functional way and regain full range of motion.”
Past studies from the team successfully demonstrated the integration of their engineered discs, known as disc-like angle ply structures (DAPS), in rat tails for 5 weeks. This latest research extended that time period in the rat model—up to 20 weeks—but with revamped engineered discs, known as endplate-modified DAPS, or eDAPS, to mimic the structure of the native spinal segment. The addition of the endplates helped to retain the composition of the engineered structure and promote its integration into the native tissue.
MRI, along with histological, mechanical, and biochemical analyses, showed that the eDAPS restored native disc structure, biology, and mechanical function in the rat model. Building off that success, the researchers then implanted the eDAPS into the cervical spine of goats. They chose the goat because its cervical spinal disc dimensions are similar to humans’ and goats have the benefit of semi-upright stature.
Researchers demonstrated successful total disc replacement in the goat cervical spine. After 4 weeks, matrix distribution was either retained or improved within the large-scale eDAPS. MRI results also suggest that disc composition at eight weeks was maintained or improved, and that the mechanical properties either matched or exceeded those of the native goat cervical disc, the release explains.
“I think it’s really exciting that we have come this far, from the rat tail all the way up to human-sized implants,” states Harvey E. Smith, MD, an associate professor of Orthopaedic Surgery and Neurosurgery at the Perelman School of Medicine and Staff Surgeon at the CMC VAMC, and co-senior author and clinical lead on the study.
“When you look at the success in the literature from mechanical devices, I think there is a very good reason to be optimistic that we could reach that same success, if not exceed it with the engineered discs,” he adds.
The next step will be to conduct longer-term studies to further characterize the function of the eDAPS in the goat model, the authors continue, as well as model the degeneration of spinal discs in humans and to test how their engineered discs perform in that context.
“There is a lot of desirability to implant a biological device that is made of your own cells,” Smith comments. “Using a true tissue-engineered motion preserving replacement device in arthroplasty of this nature is not something we have yet done in orthopaedics. I think it would be a paradigm shift for how we really treat these spinal diseases and how we approach motion sparing reconstruction of joints.”
[Source(s): Perelman School of Medicine at the University of Pennsylvania, Newswise]
