The Topical Administration of Rhegf-Loaded Nanostructured Lipid Carriers (Rhegf-Nlc) Improves Healing in a Porcine Full-Thickness Excisional Wound Model

The development of an effective treatment able to reduce the healing time of chronic wounds is a major health care need. In this regard, our research group has recently demonstrated the in vivo effectiveness of the topical administration of rhEGF-loaded lipid nanoparticles in healing-impaired db/db mice. Here we report the effectiveness of rhEGF-NLC (rhEGF loaded nanostructured lipid carriers) in a more relevant preclinical model of wound healing, the porcine full-thickness excisional wound model. The rhEGF-NLC showed a particle size of around 335nm, negative surface charge (-27mV) and a high encapsulation efficiency of 94%. rhEGF plasma levels were almost undetectable, suggesting that no systemic absorption occurred, which may minimise potential side effects and improve treatment safety. In vivo healing experiments carried out in large white pigs demonstrated that 20μg of rhEGF-NLC topically administered twice a week increased the wound closure and percentage of healed wounds by day 25, compared with the same number of intralesional administrations of 75μg free rhEGF and empty NLC. Moreover, rhEGF-NLC improved the wound healing quality expressed in terms of number of arranged microvasculature, fibroblast migration and proliferation, collagen deposition and evolution of the inflammatory response. Overall, these findings demonstrated that topically administered rhEGF-NLC may generate de novo intact skin after full thickness injury in a porcine model, thereby confirming their potential clinical application for the treatment of chronic wounds.