As people grow older, disc degeneration becomes common. Over time, the soft, compressible discs that work as the spine's shock absorbers break down. This degeneration mainly happens in the neck and lower back and can cause intense pain. Those who suffer from disc degeneration also often face herniated discs, osteoarthritis, and spinal narrowing.
Previous research has shown that re-implanting the jelly-like cushion found between spinal discs or using stem cells can delay the degeneration. Several companies offer these strategies, but their methods are relatively ineffective. Scientists at Duke University believe that new cell therapies can stop and even reverse the degeneration. However, there's a catch — to use cell therapies, scientists have to keep the cells alive, synthesize the appropriate replacement material, and get it in the right place in a patient's spine. Duke's Pratt School of Engineering may have solved that problem.
In a recent study, graduate student Aubrey Francisco and biomedical engineering professor Lori Setton describe a new biomaterial designed to deliver a sort of booster shot of reparative cells to the jelly-like cushion between spinal discs. This material — the nucleus pulposus (NP) — distributes pressure and provides spinal mobility, relieving back pain.
"Our primary goal was to create a material that would be liquid at the start, gel after injection in the disc space and keep the cells in the location where they're needed," Setton said. "Our second goal was to create a material that would provide the delivered cells with the environmental cues to promote their persistence and biosynthesis."
This delivery strategy keeps the cells in place and provides the spine with something that mimics laminin — a protein native to NP tissue. Laminin is generally found in healthy spinal discs, but is missing in those that have degeneration. This laminin-like material — which is delivered as a biogel — allows injected cells to attach and remain in place. It also could possibly enable the cells to last longer and produce more of the appropriate structural underpinning of the discs to help stop degeneration.
After testing this concept on rats, researchers discovered that 14 days after injection, more cells remained in place when delivered this way compared to cells delivered in a liquid suspension. These preliminary results could have an impact on the future of cell therapy. However, Setton said that more work would be needed to optimize equipment models that deliver cells to larger sites closer to human size.
"The concept is that these cells will be promoted to produce matrix that can support tissue regeneration or arrest degeneration," Setton said. "Additional studies that evaluate disc height or matrix hydration following cell delivery would be important to achieve this goal. There's definitely interest and certainly real potential there."