Characterisation of epidermal regeneration in vivo: a 60-day follow-up study

Objective: To characterise the long-term course of epidermal regeneration in a suction-blister wound model in healthy humans. Method: A single-centre, prospective cohort study was conducted. Suction blister wounds of 8mm diameter were created on the volar forearms of healthy volunteers. Planimetry was used to measure the wound surface area. Transepidermal water loss was estimated to characterise the skin barrier function. Skin brightness was measured using the chromametric luminance L*parameter and skin (visco) elastic properties were measured by a controlled suction device. Results: Thirty-two subjects (mean age 28.6 years) participated. Epithelisation was nearly completed after 8 days, but it took approximately 3 weeks for complete skin barrier restoration. Post-inflammatory hyperpigmentation was observed at the end of day 60 in the majority of skin areas. Elastic and viscoelastic deformation and recovery at the end of the follow-up period did not reach baseline values. Conclusion: Newly formed epidermis requires considerable time before reaching complete recovery of the skin barrier function. Up to 2 months after the injury, regenerated epidermis in junction with the reticular dermis is stiffer compared to before. Under mechanical loading increased local stiffness might increase the risk for subsequent injuries at the same or adjacent skin areas. Due to its increased vulnerability it is recommended to protect or to offload the epidermal tissue as long as possible to support the structural long-term regeneration. Artificial suction blister wounds are well standardised and controlled models for a wide range of clinical studies and they offer advantages over uncontrolled patient conditions in wound healing studies.