Intervertebral disc degeneration in warmblood horses: Histological and biochemical characterization.
Authors: Bergmann Wilhelmina, de Lest Chris van, Plomp Saskia, Vernooij Johannes C M, Wijnberg Inge D, Back Willem, Gröne Andrea, Delany Mark W, Caliskan Nermin, Tryfonidou Marianna A, Grinwis Guy C M
Journal: Veterinary pathology
Summary
Intervertebral disc degeneration follows broadly similar patterns across mammalian species, yet horses exhibit distinct biochemical signatures that warrant targeted clinical understanding. Researchers examined 139 discs from 33 warmblood horses using histological grading and biochemical analysis (measuring hydration, glycosaminoglycans, collagen types, and advanced glycation end-products), identifying that gross degenerative changes correlate most reliably with nucleus pulposus tearing and annulus fibrosus vascular proliferation rather than with age alone. Unlike dogs and humans, equine discs showed no consistent relationship between glycosaminoglycan content and degeneration, but revealed striking accumulation of advanced glycation end-products (AGEs) and fibrotic remodelling with age and degeneration—changes most pronounced in the nucleus pulposus, suggesting this region initiates degenerative cascade. The caudal cervical spine emerged as particularly vulnerable, with significantly elevated AGE deposition and increased total collagen in grossly normal discs, indicating early microstructural compromise that precedes clinical signs. For practitioners, these findings suggest that biochemical markers like AGE accumulation may better predict disc pathology in horses than traditional histological parameters, potentially enabling earlier intervention in high-risk spinal regions before functional impairment develops.
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Practical Takeaways
- •Degeneration in equine discs appears to initiate in the nucleus pulposus rather than annulus fibrosus, differing from other species; monitor caudal cervical region closely as this area shows accelerated biochemical changes even before gross pathology appears
- •The absence of notochordal cells in horses and different biochemical patterns compared to humans/dogs means equine-specific understanding of disc degeneration is needed for accurate diagnosis and prognosis of cervical spinal disease
- •Biochemical markers like AGE accumulation precede visible degenerative changes in caudal cervical discs, suggesting potential for early detection of spinal disease through advanced diagnostic methods before clinical signs develop
Key Findings
- •Nucleus pulposus tearing and annulus fibrosus changes correlated with gross degeneration in equine intervertebral discs
- •Age and degeneration were positively associated with advanced glycation end-products and fibrotic phenotype
- •Unlike dogs and humans, horses showed no consistent decrease in glycosaminoglycan content or hydration with age or degeneration
- •Caudal cervical nuclei pulposi demonstrated significantly increased AGE deposition even in grossly normal discs, indicating elevated biomechanical stress in this region