Human skin cell fractions fail to self-organize within a gellan gum/Hyaluronic acid matrix but positively influence early wound healing

Split-thickness autografts still are the current gold standard to treat skin, upon severe injuries. Nonetheless, autografts are dependent on donor site availability and often associated to poor quality neoskin. The generation of dermal–epidermal substitutes by tissue engineering is seen as a promising strategy to overcome this problematic. However, solutions that can be safely and conveniently transplanted in one single surgical intervention are still very challenging as their production normally requires long culture time, and graft survival is many times compromised by delayed vascularization upon transplantation. This work intended to propose a strategy that circumvents the prolonged and laborious preparation period of skin substitutes and allows skin cells self-organization toward improved healing. Human dermal/epidermal cell fractions were entrapped directly from isolation within a gellan gum/hyaluronic acid (GG-HA) spongy-like hydrogel formed from an off-the-shelf dried polymeric network. Upon transplantation into full-thickness mice wounds, the proposed constructs accelerated the wound closure rate and re-epithelialization, as well as tissue neovascularization. A synergistic effect of the GG-HA matrix and the transplanted cells over those processes was demonstrated at early time points. Despite the human-derived and chimeric blood vessels found, the proposed matrix did not succeed in prolonging cells residence time and in sustaining the self-organization of transplanted human cells possibly due to primitive degradation. Despite this, the herein proposed approach open the opportunity to tackle wound healing at early stages contributing to re-epithelialization and neovascularization.We thank the Hospital da Prelada (Porto), in particular Dr. Paulo Costa for lipoaspirates collection and to financial support by Skingineering (PTDC/SAU-OSM/099422/2008), Portuguese Foundation for Science and Technology (FCT)-funded project. The research leading to these results has also received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. REGPOT-CT2012-316331-POLARIS