For the first time, scientists have combined six native skin cell types with a special hydrogel to "print" thick, multi-layered skin that can successfully fuse with surrounding tissue after transplantation, allowing for faster wound healing and fewer scars. "Integrated skin healing is a major clinical challenge affecting millions of people worldwide, yet options are limited,"
said lead author Dr. Anthony Atala, director of the Wake Forest Institute for Regenerative Medicine (WFIRM). "The results show that it is possible to create full-thickness human bioengineered skin that promotes faster healing and a more natural-looking result."
The printed skin features keratinocytes, dermal fibroblasts, adipocytes, melanocytes, hair follicle dermal papilla cells, and dermal microvascular endothelial cells, replicating real skin with three layers: a thin protective outer epidermis, a middle fibrous and supportive dermis, and a fat subdermis at the bottom.
When transplanted into mouse wounds, the printed skin formed blood vessels and skin patterns and showed normal tissue development. The result is faster wound healing, less skin shrinkage, and more collagen production, resulting in fewer scars. Through cell-specific staining, the WFIRM team confirmed the successful integration of the bioprinted cells with the regenerated skin during the healing process.
The researchers then used a larger 5 cm x 5 cm (2 in x 2 in) bioprinted porcine skin graft to cover the full-thickness wound on the porcine model. The results showed that wounds after pig skin grafts healed well, with increased collagen production and reduced skin shrinkage and fibrosis (or scarring).
Because harvesting large amounts of skin from other parts of the body is risky and has limited conditions, the success of larger areas of autologous skin transplantation brings great hope for human treatment.
Lab-prepared skin is a growing area of medical research, and companies are looking to use it to test products instead of using animals. But this is the first time a product of this complexity and thickness has been produced and shown complete wound healing in preclinical studies. The team now hopes to use it in human studies.
The study was published in the journal Science Translational Medicine.