Does BMP2 play a role in the pathogenesis of equine degenerative suspensory ligament desmitis?
Authors: Madeline Young, Olaniyi Moshood, Jian Zhang, C. A. Sarbacher, P. Mueller, J. Halper
Journal: BMC Research Notes
Summary
Degenerative suspensory ligament desmitis (DSLD) causes progressive lameness and pain in horses without preceding trauma, underpinned by aberrant accumulation of proteoglycans—particularly decorin with abnormally glycosylated chains—throughout connective tissues. Young and colleagues used immunohistochemistry to investigate whether bone morphogenetic protein 2 (BMP2), a chondrogenic growth factor, drives this pathological process, hypothesising that BMP2 production in fibroblast and tenoblast foci represents an early initiating event. BMP2 was localised specifically within these cellular aggregates in affected suspensory ligaments and tendons, whereas transforming growth factor beta (TGFβ) and dermatan sulfate epimerase (involved in glycosaminoglycan chain glycosylation) showed minimal staining in both DSLD and control tissues. These findings suggest that chondrogenic signalling via BMP2, rather than altered enzymatic glycosylation alone, may be central to DSLD pathogenesis and progression. For practitioners, this work provides mechanistic insight into DSLD as a growth factor-mediated disorder of proteoglycan metabolism, potentially opening avenues for therapeutic intervention targeting aberrant BMP2 signalling rather than symptomatic management of lameness alone.
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Practical Takeaways
- •DSLD involves systemic proteoglycan dysfunction driven by chondrogenic growth factors like BMP2, not just local ligament injury, which may inform future targeted therapeutic approaches
- •Understanding BMP2's role in abnormal tissue remodeling could guide development of disease-modifying treatments beyond current supportive management strategies
- •The identification of cellular foci and specific molecular markers may eventually enable earlier diagnosis and intervention in DSLD progression
Key Findings
- •BMP2 was identified via immunohistochemistry in cellular foci within tendons and suspensory ligaments from DSLD-affected horses, suggesting association with proteoglycan production
- •DSLD is characterized by abnormal accumulation of decorin with abnormally glycosylated glycosaminoglycan chains in multiple connective tissues
- •Active fibroblast/tenoblast foci were observed in some tendons and suspensory ligaments from DSLD cases, hypothesized to represent early DSLD events
- •TGFβ and dermatan sulfate epimerase showed very little staining in both control and DSLD-affected tissues, limiting their role in DSLD pathogenesis