Epithelisering

Epithelisering, or epithelialization, is the process by which epithelial cells migrate, proliferate, and differentiate to restore an intact epithelial surface after tissue injury. It is a key phase of wound healing, responsible for reestablishing the barrier function of skin and mucous membranes.

In the early phase of re-epithelialization, keratinocytes at the wound edges become activated and migrate as a sheet across the wound bed. These cells then proliferate to supply additional epithelial layers and eventually form a stratified epidermis. The process relies on a permissive wound bed, an intact basement membrane, and signaling from fibroblasts, macrophages, and other cells, with growth factors such as epidermal growth factor (EGF) and keratinocyte growth factor (KGF/FGF7) guiding migration and proliferation.

Factors influencing the rate and quality include oxygen supply, moisture, temperature, and nutrition (notably protein and zinc). Local factors such as infection, necrotic tissue, desiccation or excessive moisture, and mechanical disturbance can delay epithelialization. Systemic conditions such as diabetes or vascular disease, and medications such as corticosteroids, may slow it.

Clinically, epithelialization closes superficial wounds and restores barrier function. Mucosal surfaces often re-epithelialize rapidly compared with dermal wounds. In severe burns or full-thickness injuries, epithelialization may require grafts or dermal substitutes. Adequate epithelialization reduces infection risk and influences scar quality.