Background: Burn injuries are common and in the long term can lead to hypertrophic or keloid scars, pain and pruritus, limited mobility across joints, and disfigurement. Numerous reports suggest adipose derived tissues, including adipose derived stem cells (ADSCs) and processed lipoaspirate, can improve acutely healing wounds from a variety of etiologies including excisional, thermal, and radiation injuries by both secretion of growth factors and direct differentiation. There are many options for scar treatment, including laser therapy, silicone sheets, steroid injection, and even skin grafting however these techniques either lack optimal efficacy or involve significant cost and morbidity. Clinical case series suggest a beneficial effect of adipose tissues in improving scarred tissues, however this phenomenon has not been extensively studied in animal models especially in a thermal scar model.
Objectives: (1) Determine if adipose tissue can accelerate and improve scar remodeling subacutely after acute wound healing has occurred. (2) Determine if the effect is related to adipose derived stem cells or other components of lipoaspirate.
Methods: 50 CD1 nu/nu athymic mice received a standardized 70°C 10 second burn with a brass rod to the dorsal skin. Digital photographs and hyperspectral images were taken immediately following injury and serially over the study’s entirety. Burned skin reliably progressed through normal stages of wound healing to a scarred and granulating state. At six weeks post-burn animals received subcutaneous injection immediately beneath the scar with fresh human lipoaspirate (n=10), high dose hADSCs in matrigel (n=10), low dose hADSCs in matrigel (n=10), matrigel control (n=10), or were not injected (n=10). At 4 weeks post-injection (10 weeks post-burn) animals were sacrificed and tissue samples were harvested for histological molecular analysis.
Results: Oxygenation and perfusion profiles from hyperspectral imaging and scar wound area correlated between groups suggesting methodological consistency of burns prior to any intervention. Oxygenated hemoglobin at 10 weeks in scars treated with lipoaspirate increased significantly more compared to 6-week pre-treatment baseline than all other groups (1.57x vs. 0.85x, p
Conclusion: A consistent model of burn injury and scar maturation is described. Preliminary HSI and scar area data suggest scar improvement in lipoaspirate treated scars compared to ADSCs and controls
