Background: Hypertrophic scarring carries a large burden of disease, including disfigurement, pain and disability. There is currently no effective medical treatment to reduce or prevent hypertrophic scarring. Flightless I (Flii), a member of the gelsolin family of actin remodelling proteins, is an important negative regulator of wound repair.
Objectives: The objective of this study was to investigate the role of Flii as a potential regulator of hypertrophic scarring.
Methods: Using human skin samples and an animal model of bleomycin-induced hypertrophic scarring in mice that overexpress or have reduced expression of Flii, we investigated its effect on dermal fibrosis and hypertrophic scarring.
Results: Flii expression was increased in human burns and hypertrophic scars. A similar increase in Flii was observed in hypertrophic scars formed in mice post-treatment with bleomycin. However, Flii-deficient (Flii(+/-) ) mice had reduced scarring in response to bleomycin evidenced by decreased dermal thickness, smaller cross-sectional scar areas, fewer myofibroblasts and a decreased collagen I/III ratio. In contrast, bleomycin-treated Flii-overexpressing mice (Flii(Tg/Tg) ) showed increased scar dermal thickness, larger cross-sectional scar areas, more myofibroblasts and an increased collagen I/III ratio. Injecting developing scars with a Flii neutralizing antibody led to a significant reduction in the size of the scars and a reduction in the collagen I/III ratio.
Conclusions: This study identifies Flii as a profibrotic agent that contributes to excessive scar formation. Reducing its activity using neutralizing antibodies is a promising approach for reducing hypertrophic scarring.
© 2015 British Association of Dermatologists.