Epithelialisering

Epithelialisering, also known as epithelialization, is the process by which new epithelial cells cover a wound during the proliferative phase of wound healing. It restores the epithelial barrier, protects against infection, and reduces fluid loss. In humans, epithelialization begins after the inflammatory phase, when keratinocytes at the wound edges become activated, detach from their basement membranes slightly, and migrate as a sheet across the wound bed. Over several days, these cells proliferate, re-stratify, and re-establish a continuous epidermal layer from the wound margins toward the center. The process relies on a moist, well-vascularized wound environment and signals such as epidermal growth factor, transforming growth factor-β, keratinocyte growth factor, and others, as well as remodeling of the basement membrane by matrix metalloproteinases.

Migration is the initial driving force, followed by proliferation to replace lost cells and re-establish the stratified structure. The pace of epithelialisering depends on wound depth, location, and tissue type; mucosal surfaces often re-epithelialize rapidly, while full-thickness skin wounds require reconstitution from adnexal structures. Adequate nutrition, perfusion, absence of infection, and glycemic control support timely epithelialisering. Conversely, necrotic tissue, desiccation, chronic inflammation, or comorbidities such as diabetes can impair it and contribute to chronic wounds.

Clinically, the rate and completeness of epithelialisering are important indicators of healing progress. Insufficient epithelialization can lead to prolonged wound exposure and scarring, while excessive or aberrant epithelial proliferation can result in hyperkeratosis or scar tissue. Epithelialisering is a component of the proliferative phase and interacts with granulation tissue and angiogenesis to restore intact skin or mucosa.