Preliminary observations on expression of transforming growth factors beta1 and beta3 in equine full-thickness skin wounds healing normally or with exuberant granulation tissue.
Authors: Theoret Christine L, Barber Spencer M, Moyana Terence N, Gordon John R
Journal: Veterinary surgery : VS
Summary
# Editorial Summary Exuberant granulation tissue (EGT) remains a significant clinical challenge in equine wound management, particularly on distal limbs, yet the biological mechanisms driving its pathological development remain incompletely understood. Théoret and colleagues used an experimental model on four young horses (2–4 years old), creating matched full-thickness skin wounds on both metacarpi—one left unbandaged to heal normally and the other bandaged to promote EGT—then serially biopsied these wounds over 14 days to quantify transforming growth factor (TGF)-beta1 and TGF-beta3 expression via ELISA at multiple timepoints. Both growth factors demonstrated different temporal patterns: TGF-beta1 peaked early and remained elevated throughout healing, whilst TGF-beta3 expression was delayed; notably, bandaged wounds developing EGT showed a trend towards higher fibrogenic TGF-beta1 concentrations and lower antifibrotic TGF-beta3 concentrations compared with normally healing wounds, though these differences did not reach statistical significance. These preliminary observations suggest that the imbalance between pro-fibrotic and anti-fibrotic cytokine signalling may be a key driver of EGT pathogenesis, pointing towards potential future therapeutic strategies targeting this growth factor dysregulation—such as selective TGF-beta modulation—as a means of preventing or limiting EGT development in clinical patients. Whilst this small study provides valuable mechanistic insight, larger-scale investigation with adequate statistical power will be essential before translating these findings into evidence-based wound management protocols.
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Practical Takeaways
- •Bandaging of equine metacarpal wounds promotes exuberant granulation tissue development; awareness of this iatrogenic effect should inform wound management protocols
- •Future therapeutic approaches targeting growth factor expression (enhancing TGF-beta3 or inhibiting TGF-beta1) may help prevent problematic EGT in equine limb wounds
- •This preliminary molecular evidence supports clinical observation that wound environment manipulation affects healing outcomes—consider open-air or alternative management for distal limb wounds at risk of EGT
Key Findings
- •TGF-beta1 expression peaked early and remained elevated through 14 days in all wounds, with higher concentrations in bandaged wounds developing EGT
- •TGF-beta3 expression was delayed compared to TGF-beta1, with higher concentrations in normally healing wounds
- •Wounds with EGT showed a tendency toward higher fibrogenic TGF-beta1 and lower antifibrotic TGF-beta3, suggesting a molecular basis for excessive granulation tissue formation
- •The balance between pro-fibrogenic (TGF-beta1) and anti-fibrotic (TGF-beta3) growth factors may regulate whether equine limb wounds heal normally or develop EGT