OSAKA, Japan — A new biomaterial can help regenerate tissue in people dealing with chronic lower back pain and spinal issues. Researchers in Japan say the secret to this breakthrough therapy is all in the hiPS. Not those hips, but human induced pluripotent stem cells.
A team from Osaka and Kyoto Universities explain that a common cause of lower back pain is the degeneration of intervertebral discs (IVDs). These discs sit between the vertebrae in the spine and help give the spinal column its flexibility. Severe IVD degeneration eventually leads to spinal deformity without treatment. In the new study, scientists used cartilage tissue derived from stem cells to build back lost IVDs in lab rats.
What causes IVD degeneration?
Researchers believe this problem starts in the nucleus pulposus (NP) — the inner core of the vertebral disc. NP cells produce the surrounding extracellular matrix (ECM), which supports these cells and gives the NP its elasticity.
Although other treatments which use viable NP cells to fix the ECM have been promising, they lose their effectiveness in advanced cases of IVD degeneration. In people with severe degeneration in their spines, there aren’t enough of these cells present to respond to treatment.
With that in mind, the team looked at creating an implant which carries the necessary cells already. From there, the implant can create and regenerate the ECM that the NP cells form.
“The ECM of the NP is a network of collagen that acts as scaffolding for other important proteins. Interestingly, this composition is similar to the ECM of articular cartilage,” says lead author Takashi Kamatani in a media release. “Thus, we hypothesized that cell types that can produce and support cartilage could be useful for treating IVD degeneration.”
The hiPS don’t lie
Study authors used induced pluripotent stem cells (iPSCs) during their experiments. These cells are basically the building blocks of development, turning into other types of cells as a person grows from an infant to an adult. They also don’t have the growth and division limits that NP cells do.
Importantly, scientists are capable of turning iPSCs into chondrocytes — cells that produce and maintain cartilage. Previous studies have successfully used this same method to treat cartilage defects in animals.
In the new study, researchers created human iPSC-derived cartilaginous tissue (hiPS-Cart) that they implanted into rats with no NP cells in their intervertebral discs.
“The hiPS-Cart implanted in these rats was able to survive and be maintained,” explains senior author Noriyuki Tsumaki. “IVD and vertebral bone degeneration were prevented. We also assessed the mechanics and found that hiPS-Cart was able to revert these properties to similar levels observed in the control rats.”
The team also studied the gene expression of the hiPS-Cart six weeks after the procedure. Results show hiPS-Cart displayed the same characteristics of chondrocyte-like NP cells, instead of another type of NP cell called notochordal. Researchers say this means chondrocyte-like cells are able to restore spinal health and function on their own.
“Our findings provide strong support for using this hiPS-Cart system in the development of treatments for human IVD degeneration,” Kamatani concludes.
The study is published in the journal Biomaterials.