Views on Cartilage Injury and Potential Remedies

Our newest article is in the Journal of Orthopaedic Trauma’s “OTA Basic Science Focus Issue“. Dr Joseph Borrelli organized an excellent discussion by researchers and traumatologists on articular cartilage injuries and potential remedies. We contributed a section on early injury responses in PTOA. Read it on PubMed or JOT.

Journal of Orthopaedic Trauma Article

Forming More Bone with Less BMP2 Growth Factor

The growth factor BMP2 is used clinically to help form bone in difficult surgeries such as spinal fusions and fracture non-unions. In these surgeries, BMP2 is effective when used at milligram doses. However, this is roughly a million-fold more BMP2 than occurs naturally, and such great doses can lead to undesired side-effects. Clearly we need to better understand how BMP2 works and overcome this discrepancy in activities.

It’s been long known that extracellular matrix can affect the cellular responses to growth factors. But exactly how and why this occurs still remains elusive, especially for BMP2. One mechanism might be by increasing the local concentration of the growth factor presented to the cells. We previously showed that COMP is an extracellular matrix protein that can bind up to ten BMP2 or TGFbeta growth factors. This multivalent binding of BMP2 to COMP enhances the biological activity of BMP2. Here we apply this finding to a rat model of spinal fusion, and show that we can achieve an equivalent bone-inducing activity with a reduced amount of BMP2.

This study was published in the journal “Spine“. It represents a collaborative effort involving basic and clinical scientists at the UC Davis Department of Orthopaedic Surgery, and biomaterials researchers at the UC Davis Department of Biomedical Engineering.

MicroCT of Spinal Fusion

Cellular Responses to Injury can Further Damage Cartilage

We explore whether the cellular responses to an impact injury can affect cartilage integrity. We identified cell-mediated damage, which is in addition to the mechanical damage caused by the immediate impact of an injury. We used a cartilage explant injury model to demonstrate that when we prevent activation of primary response genes in cells, we can protect the injured cartilage from inflammation, apoptosis, and subsequent matrix degradation. Read more at the publishers site.

This manuscript was accepted for publication at the eCM Journal, a high quality not-for-profit open access journal published by scientists at the AO Foundation.

PostTraumatic Arthritis Chapter/Book

Our chapter on “Closed Joint ACL Disruption Murine Model of PTA” is published in “Post-Traumatic Arthritis: Pathogenesis Diagnosis and Management” edited by Steven Olson and Farshid Guilak. The book provides a comprehensive discussion of the current thinking on post-traumatic arthritis, from both the research and clinical perspective, and is definitely worth a look.
PTA Cover

Knee Surgery for OA – Some Harm, Little Benefit, Exercise is Better!

This study is an interesting systematic review and meta-analysis of arthroscopic knee surgeries performed on middle-aged adults with knee pain. The authors conclude that knee surgeries offer only mild short term benefits, and can cause harm. Event the short-term benefits are “markedly smaller than that seen from exercise therapy as treatment for knee osteoarthritis”. This is being covered by the Wall Street Journal and New York Times.