High Numbers of CD163-Positive Macrophages in the Fibrotic Region of Exuberant Granulation Tissue in Horses.
Authors: Du Cheyne Charis, Martens Ann, De Spiegelaere Ward
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Exuberant granulation tissue (EGT) remains a significant complication during second intention healing of equine distal limb wounds, yet the immunological mechanisms driving its development remain poorly understood. Du Cheyne and colleagues used immunohistological staining to characterise inflammatory cell populations in EGT-affected tissue compared with experimentally induced wounds at 19 days post-injury, specifically examining both pro-inflammatory macrophages (MAC387+) and pro-resolution macrophages (CD163+). The fibrotic regions of EGT tissue contained markedly elevated numbers of both cell types, but CD163+ cells—which promote fibroblast proliferation and tissue remodelling—were disproportionately abundant, suggesting that healing becomes pathologically arrested during the proliferation phase rather than progressing normally towards tissue maturation and remodelling. These findings indicate that EGT development may result from dysregulated macrophage function that perpetuates a fibrotic microenvironment, rather than from a simple overabundance of inflammatory activity. Understanding this immunological signature could eventually inform therapeutic strategies to promote resolution of EGT, potentially through selective manipulation of macrophage phenotypes to shift wounds away from a pro-fibrotic state.
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Practical Takeaways
- •Exuberant granulation tissue development appears linked to abnormal immune cell accumulation that stalls wound healing in the proliferation phase—understanding this mechanism may lead to better therapeutic interventions
- •The persistence of CD163+ macrophages in EGT suggests that anti-inflammatory or immune-modulating treatments targeting these cells could potentially prevent or resolve excessive granulation tissue formation
- •Early recognition of abnormal inflammatory responses in equine distal limb wounds may allow intervention before EGT becomes established
Key Findings
- •Significantly higher numbers of MAC387+ inflammatory cells detected in fibrotic regions of EGT compared to 19-day-old experimental wounds
- •CD163+ pro-resolution macrophages were substantially elevated in EGT fibrotic regions, suggesting arrest at the proliferation phase of wound healing
- •Persistent inflammatory response characterized by high fibrosis-promoting immune cell populations distinguishes EGT-developing wounds from normal healing progression