Chronic back and neck pain often results from progressive damage to the discs separating the vertebrae from the spine (intervertebral discs). Discs developed in bioengineering and from our own cells could remedy this. They are no longer prostheses but real replacement structures.
A new study, published in Science Translational Medicine, describes the fabrication of a new bioengineered intervertebral disc to replace a deteriorated intervertebral disc. This new disc is not likely to be rejected since it is manufactured in the laboratory using the own cells of patients suffering from neck and back pain. The study, conducted by a team of American researchers, was carried out on rats, then goats.
Healthy intervertebral discs serve as both joints and shock absorbers between the vertebrae. They work by absorbing the stress on the spine when we move and adjusting our posture in the same way as a car suspension. Disc wear can cause pain in different areas of the back or neck.
“A major step”
The researchers wanted to combine patient or animal stem cells with biomaterial assemblies in the lab to create a composite structure to be implanted into the spine to serve as a replacement disc. Stem cells have the potential to “transform” into specialized cells, hence their massive use in many medical researches.
Over the past 15 years, the team of researchers has developed a replacement disc for tissue engineering, moving from basic in vitro scientific experiments to real-world transplantations in small animals and then in larger animals: in perspective, trials on humans.
“This is a major step: constructing a disc of this size in a lab, inserting it and then integrating it with the surrounding tissue. It’s very promising,” says Robert L. Mauck, co-lead author of the study. “We thus hope, with this device, to replace the disc in a biological and functional way and to regain the full range of motion.”, he added.
From success to success
First, the researchers tested the new discs – called “disc-like angle ply structures” or “disc-like right-angle ply structures” (DAPS) – in rat tails for 5 weeks. In new research , the team further perfected the replacement discs by modifying them, a new disc called eDAPS, to mimic the structure of the native vertebral segment.They tested this new model in rats again, but this time for up to 20 weeks. In several tests, the researchers found that, in the case of the rat, eDAPS effectively restored the structure and function of the original disc.
Building on these successes, the researchers then implanted the eDAPS in the cervical spine of goats. The goat was chosen because its cervical vertebral discs are similar in size to humans and these animals benefit from a semi-erect stature. After four weeks, the trial is conclusive: the eDAPS integrate well with the surrounding tissues and the mechanical function of the discs corresponds at least, or even better, to that of the original cervical discs of the goats.
“Very good reasons to be optimistic”
“I think it’s really exciting that we’ve gone this far, from rat tails to human-sized implants,” said study co-lead author Dr. Harvey E. Smith. “I think there’s very good reason to be optimistic that we could achieve that same success, if not surpass it, with the men’s technical drives.”
For the researchers, the next step will be to conduct further, more extensive trials on goats, to better understand the effectiveness of the eDAPS treatment. Additionally, the research team plans to test eDAPS in cases of human intervertebral disc degeneration.
“It’s best to implant a biological device made from our own cells,” notes Dr. Smith, adding that “we’re in the process of using a true tissue-engineered motion-preserving replacement device. Which doesn’t has ever been done in orthopaedics.”
.
