Nope. Well maybe not exactly endochondral ossification, but a very similar mechanism. Let me explain...Researchers at Stanford have recently come up with a way to regenerate cartilage in the joints of mice. Typically, if one wanted to regenerate cartilage they would drill tiny microfractures into the tissue which would promote the damaged cartilage to create fibrocartilage. While this is new tissue covering the bone, according to the co-author on the paper Dr. Chan, it is not the same. The fibrocartilage that results is primarily in the form of scar tissue, does not have the elasticity of natural cartilage, and degrades relatively quickly.
So how does it work? The researchers had the idea to stimulate the tissue to act like it is going to start forming bone again, but then stop it at the cartilage phase (this is my endochondral ossification analogy). To do so, they start with the same first step of drilling small microfractures into the damaged cartilage tissue then add a molecule called "bone morphogenetic protein 2" (BMP2). BMP2 initiates the formation of bone at these microfracture sites. Next, in order to stop the process midway through the bone development they add a signal blocking molecule called "vascular endothelial growth factor" (VEGF) which halts the development at the cartilage stage. BAM! You've got a product that resembles natural cartilage in its mechanical properties, unlike the scar tissue-like fibrocartilage. Furthermore, the mice had improved mobility in their previously-arthritic joints and a reduction in pain (not sure how they objectively measured this).
While the researchers have not taken to human trials yet, they did implant human tissue into mice and were able to see very similar outcomes. While they plan to start human trials soon, they are hopeful for a fast-moving clinical period, as both BMP2 and VEGF are already FDA approved for use in other treatments. Dr. Longaker, the other co-author, reports that their goal is to address arthritic joints and rejuvenate that cartilage before the condition comes to the point of full joint replacements.
References:
Murphy, M. P., Koepke, L. S., Lopez, M. T., Tong, X., Ambrosi, T. H., Gulati, G. S., Marecic, O., Wang, Y., Ransom, R. C., Hoover, M. Y., Steininger, H., Zhao, L., Walkiewicz, M. P., Quarto, N., Levi, B., Wan, D. C., Weissman, I. L., Goodman, S. B., Yang, F., Longaker, M. T., … Chan, C. (2020). Articular cartilage regeneration by activated skeletal stem cells. Nature medicine, 26(10), 1583–1592. https://doi.org/10.1038/s41591-020-1013-2
https://med.stanford.edu/news/all-news/2020/08/Researchers-find-method-to-regrow-cartilage-in-the-joints.html
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