Osteopontin expression in healing wounds of horses and in human keloids.
Authors: Miragliotta V, Pirone A, Donadio E, Abramo F, Ricciardi M P, Theoret C L
Journal: Equine veterinary journal
Summary
# Editorial Summary: Osteopontin Expression in Equine and Human Fibrotic Wounds Excessive scarring and fibroproliferation represent significant clinical challenges in equine practice, particularly exuberant granulation tissue, yet the molecular mechanisms driving these conditions remain incompletely understood. Miragliotta and colleagues investigated osteopontin (OPN) expression across normal healing wounds, pathological equine granulation tissue, and human keloids using quantitative PCR and immunohistochemistry, reasoning that OPN—a protein implicated in fibrosis across multiple species and organ systems—might contribute to aberrant wound healing responses. Whilst OPN gene expression was baseline-detectable in intact equine skin and increased throughout the normal wound-healing phases before declining at closure, protein expression showed a distinctly different pattern: absent in normal skin and at wound edges, but present in dermal inflammatory cells during healing, and critically, persisting in fibrotic tissues where it localised to epidermis, infiltrating immune cells, endothelial cells and fibroblasts in both equine exuberant granulation tissue and human keloids. The striking parallel between equine and human fibrotic wound pathology—specifically the sustained, widespread OPN immunoreactivity in pathological compared to normally healing tissues—strengthens the case for OPN as a therapeutic target in horses prone to excessive granulation tissue formation. Future work exploring OPN suppression as an intervention may offer farriers, veterinarians and rehabilitation professionals a mechanistically grounded approach to managing one of equine practice's more persistent complications.
Read the full abstract on PubMed
Practical Takeaways
- •Exuberant granulation tissue in horses shows persistent osteopontin expression similar to human keloids, suggesting common fibroproliferative mechanisms that could be therapeutically targeted to reduce excessive scarring
- •Downregulation of osteopontin represents a rational therapeutic objective for managing problematic wound healing and excessive granulation tissue in equine practice
- •Understanding osteopontin's role in fibrosis may guide development of topical or systemic interventions to improve healing outcomes and reduce cosmetic and functional complications in equine wounds
Key Findings
- •Osteopontin gene expression increases throughout equine wound healing phases with final decrease at closure, while protein is absent in normal skin
- •Dermal osteopontin protein in healing wounds is confined to inflammatory cells, distinguishing normal healing from fibrotic responses
- •Exuberant granulation tissue and human keloids show persistent osteopontin immunoreactivity in epidermis, inflammatory cells, endothelial cells and fibroblasts, indicating a role in fibroproliferation
- •Different patterns of osteopontin expression between normally healing and fibrotic wounds suggest this protein as a therapeutic target for controlling excessive scarring