In vivo efficacy proof of concept of a large-size bioprinted dermo-epidermal substitute for permanent wound coverage

Abstract

<b>Introduction:</b> An autologous split-thickness skin graft (STSG) is a standard treatment for coverage of full-thickness skin defects. However, this technique has two major drawbacks: the use of general anesthesia for skin harvesting and scar sequelae on the donor site. In order to reduce morbidity associated with STSG harvesting, researchers have developed autologous dermo-epidermal substitutes (DESs) using cell culture, tissue engineering, and, more recently, bioprinting approaches. This study assessed the manufacturing reliability and <i>in vivo</i> efficacy of a large-size good manufacturing practice (GMP)-compatible bio-printed human DES, named Poieskin^®, for acute wound healing treatment. <b>Methods:</b> Two batches (40 cm² each) of Poieskin^® were produced, and their reliability and homogeneity were assessed using histological scoring. Immunosuppressed mice received either samples of Poieskin^® (<i>n</i> = 8) or human STSG (<i>n</i> = 8) immediately after longitudinal acute full-thickness excision of size 1 × 1.5 cm, applied on the skeletal muscle plane. The engraftment rate was assessed through standardized photographs on day 16 of the follow-up. Moreover, wound contraction, superficial vascularization, and local inflammation were evaluated via standardized photographs, laser Doppler imaging, and PET imaging, respectively. Histological analysis was finally performed after euthanasia. <b>Results:</b> Histological scoring reached 75% ± 8% and 73% ± 12%, respectively, displaying a robust and homogeneous construct. Engraftment was comparable for both groups: 91.8% (SD = 0.1152) for the Poieskin^® group <i>versus</i> 100% (SD = 0) for the human STSG group. We did not record differences in either graft perfusion, PET imaging, or histological scoring on day 16. <b>Conclusion:</b> Poieskin^® presents consistent bioengineering manufacturing characteristics to treat full-thickness cutaneous defects as an alternative to STSG in clinical applications. Manufacturing of Poieskin^® is reliable and homogeneous, leading to a clinically satisfying rate of graft take compared to the reference human STSG in a mouse model. These results encourage the use of Poieskin^® in phase I clinical trials as its manufacturing procedure is compatible with pharmaceutical guidelines.