Donate to Science & Enterprise

S&E on Mastodon

S&E on LinkedIn

S&E on Flipboard

Please share Science & Enterprise

Engineered Tissue-Polymer Replacement Spinal Discs Developed

Spine model

(Michael Dorausch, Flickr)

23 Nov. 2018. Vertebrae discs made with engineered tissue from stem cells and biocompatible polymer hydrogels were shown in tests with lab animals to have comparable properties to natural spinal discs. Researchers from University of Pennsylvania and nearby institutions reported their findings in Wednesday’s issue of the journal Science Translational Medicine (paid subscription required).

Back and neck pain are common problems affecting growing numbers of people, which according to the authors, affects 2 of 3 adults in their lifetimes, as well as major causes of disability and a continuing drain on medical resources. Degeneration of discs, the soft elastic tissue between the vertebrae in the spinal column, is one of the most common sources of back and neck pain, as well as weakness and numbness in the arms and legs. In most cases, these discs that provide elasticity and act as shock absorbers in the cervical and lumbar spinal areas — neck and lower back — wear down over time. Spinal fusion surgery and mechanical replacement devices can provide relief of the pain, but do not restore the properties or functions of original discs.

The team led by UPenn orthopedic surgery professors Robert Mauck and Harvey Smith is seeking to create engineered tissue discs with those original properties. “The current standard of care,” says Mauck in a UPenn statement, “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.”

The UPenn researchers, with colleagues from Drexel University and University of Delaware, developed synthetic discs they call endplate-modified disc-like angle ply structures, or eDAPs, to replace damaged original spinal discs. Their eDAPs take advantage of progress in tissue engineering and stem cell research, and are made from hydrogels, water-based polymers held together with polycaprolactone, or PCL, a biocompatible polymer widely used in tissue engineering, and hyaluronic acid, a natural ingredient found in skin and other soft tissue.

In addition, eDAPs contain mesenchymal stem cells, so-called adult stem cells that transform into soft tissue similar to natural spinal discs, and are mixed in with the PCL/hyaluronic acid hydrogel. That mixture is then sandwiched between polymer end plates.

The researchers previously tested the short-term feasibility of eDAPs in lab rats, but in this study extended those tests over longer periods. The team implanted appropriately-sized eDAPs into the tail region of lab rats, and found they could function for as long as 20 weeks. The researchers also created more human-sized eDAP discs, which they implanted in the cervical spines of goats without complications. Those discs performed with almost the same physical properties of natural discs for up to 8 weeks. In both rats and goats, eDAP discs integrated with and matured into the host spinal columns, although in goats that maturation process was slower.

The team believes the findings provide enough of a proof-of-concept to continue research with larger animals and later into tests with humans. “This is a major step,” adds Mauck, “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.”

More from Science & Enterprise:

*     *     *

1 comment to Engineered Tissue-Polymer Replacement Spinal Discs Developed