C. M. Moles1, S. Balaji1, N. Han1, R. Ranjan1, A. Shaaban2, P. Bollyky3, T. M. Crombleholme4, S. G. Keswani1 1Cincinnati Children’s Hospital Medical Center,Laboratory for Regenerative Wound Healing,Cincinnati, OH, USA 2Cincinnati Children’s Hospital Medical Center,Center For Fetal Cellular And Molecular Therapy,Cincinnati, OH, USA 3Stanford University,Palo Alto, CA, USA 4Children’s Hospital Colorado,Aurora, CO, USA
Introduction: More than 100 million patients acquire scars annually in the developed world. Currently, there is no available anti-scar therapy. The fetal response to injury is regenerative and can serve as a roadmap to achieve postnatal scarless wound healing. Fetal wounds have high levels of IL-10, and viral over-expression of IL-10 results in postnatal regenerative wound healing. We hypothesize that delivery of IL-10 in a more clinically translatable sustained release hydrogel (HH10) can result in regenerative healing in postnatal wounds.
Methods: 4mm full thickness dorsal wounds in C57BL/6J mice were created (n=20). Wounds were harvested at 28 days post wounding and histological evaluation (H&E) and capillary density (CD 31+ caps/HPF) of uninjured skin and scars were performed. Observed differences were used to establish 5 quantifiable scar parameters. Following development of a novel scar scale, in vivo wound healing experiments testing the efficacy of HH10 were performed. Treatment groups include HH10, Gel Control, Lentiviral IL-10 (LV-IL-10) or PBS (n=4/group). HH10 is a scaffold made of 2:1:1 (hyaluronan conjugated with heparan sulphate, type-I collagen and polyethylene glycol diacrylate) and IL-10 (800ng/wound). Data presented as mean+/-SD, p-values by ANOVA or T-test.
Results: Histologic analysis demonstrates significant differences between uninjured skin and scar in epidermal height, nuclear orientation of the basal keratinocytes, scar area, dermal appendages and vascular density (column A vs. B; p<.01). HH10 treatment yields significantly improved scar parameters compared to characteristic scar in PBS wounds (column D vs. B; p<.01). Scar assessment reveals HH10 and viral over-expression of IL-10 are equally potent in achieving attenuation of scar (column D vs. C; p=ns). HH10 restores epidermal and dermal scar parameters to the levels observed in uninjured skin (column D vs. A; p=ns). Gel treatment without IL-10 improves wound healing compared to PBS (column E vs. B; p<.05), but not to levels seen with HH10 or LV-IL-10 (column E vs. D or C; p<.05).
Conclusion:
Using a novel quantifiable method to assess scars histologically, HH10 results in restoration of epidermal and dermal parameters to the levels observed in unwounded skin, the benchmark of regenerative healing. HH10 obviates some of the translatable concerns with IL-10 gene therapy, and has broad potential applications. The therapeutic benefits extend beyond the cosmetic benefit, and may apply to any disease characterized by excessive fibroplasia.
