Researchers at Stanford University School of Medicine (CA, USA) have discovered a way to regenerate cartilage in mouse and human tissue. The study was recently published in Nature Medicine, and builds on previous research at Stanford that resulted in the isolation of the skeletal stem cell responsible for the production of bone and cartilage.

“Cartilage has practically zero regenerative potential in adulthood, so once it’s injured or gone, what we can do for patients has been very limited,” commented Charles Chan (Stanford University).

Damaged cartilage can be treated using a technique that involves drilling tiny holes in the surface of a joint. This is known as microfracture, and it causes the body to generate new tissue in the joint. However, this new tissue is different to cartilage.

“Microfracture results in what is called fibrocartilage, which is really more like scar tissue than natural cartilage,” explained Chan. “It covers the bone and is better than nothing, but it doesn’t have the bounce and elasticity of natural cartilage, and it tends to degrade relatively quickly.”

Despite the common assumption that adult cartilage did not regenerate after injury, the team at Stanford used a mouse model to demonstrate that microfracture did activate skeletal stem cells. However, when left to their own devices, these activated stem cells regenerated fibrocartilage in the joint.

This led the team to consider the possibility that the healing process after microfracture could be steered toward development of cartilage, rather than fibrocartilage.

With the knowledge that cells go through a cartilage phase before turning into bone, the researchers used bone morphogenetic protein 2 (BMP2) to initiate bone formation after microfracture, before stopping the process midway using vascular endothelial growth factor (VEGF)

“What we ended up with was cartilage that is made of the same sort of cells as natural cartilage with comparable mechanical properties, unlike the fibrocartilage that we usually get,” Chan explained. “It also restored mobility to osteoarthritic mice and significantly reduced their pain.”

The researchers went on to transfer human tissue into mice, and were able to demonstrate that human skeletal cells could likewise be steered toward bone development but stopped at the cartilage stage.

The next stage of the research is to conduct similar experiments in larger animals before moving on to clinical trials.

Michael Longaker (Stanford University) also noted that the main components of a potential therapy are already approved as safe and effective by the FDA: “BMP2 has already been approved for helping bone heal, and VEGF inhibitors are already used as anti-cancer therapies. This would help speed the approval of any therapy we develop.”

Link: https://www.regmednet.com/researchers-develop-method-to-regrow-cartilage-in-arthritic-mice/