Epithelialisation

Epithelialisation is the process by which epithelial tissue covers a wound or defect, restoring barrier function. It is a central part of wound healing in skin and mucosa, driven by keratinocyte migration, proliferation, and differentiation to reconstitute a stratified epithelium across the wound bed.

Keratinocytes at the wound edge activate, detach, and migrate as a sheet over a provisional matrix rich in fibrin and fibronectin. Basement membrane is degraded to permit movement and later reassembled. Cells re-express integrins and E-cadherin and receive signals from growth factors such as EGF, TGF-α, FGF7 (KGF), and IGF-1 to proliferate and restore a multilayer epithelium with tight junctions and desmosomes.

Timing and context: Re-epithelialisation begins during the transition from inflammation to proliferation and proceeds from the wound margins inward. Superficial wounds re-epithelialise quickly, while full-thickness injuries heal more slowly and may rely on adjacent epithelial appendages. Healing quality is influenced by scar formation and the speed of barrier restoration.

Factors and clinical relevance: Age, diabetes, infection, ischemia, and corticosteroids can slow epithelialisation. Therapeutic approaches include maintaining a moist wound environment, debridement to remove necrotic tissue, and using dressings or biologics that provide a supportive substrate or growth-factor cues to promote epithelialisation.