Programmed wound healing in aged skin may be enhanced by mesenchymal cell loaded gene-activated scaffolds

Aging can prolong the wound healing and is associated with decline in stem cells, delays in cellular migration, and lower vascularization. Tissue engineering has largely evolved to incorporate advanced three-dimensional wound dressings, scaffolds, and hydrogels that may be seeded with mesenchymal stromal cells (MSCs) to foster an environment conducive to regeneration and enhance the healing process. The effectiveness of stem cell-seeded scaffolds can be improved by incorporating activating agents such as nucleic acids resulting in gene-activated scaffolds (GAS), thereby facilitating targeted wound healing in aged patients. In this study, we assess the in vivo wound healing potential of a promising MSC seeded gene-activated collagen scaffold, containing the anti-fibrotic agent β-klotho and pro-angiogenic stromal derived factor (SDF-1α) in aged male Sprague Dawley rats (20-24 month old). A MSC cell loaded split skin model compared MSC only with the clinical standard dressing +Jelonet, MSCs +gene-free collagen scaffold, and MSCs +SDF-1α/β-klotho dual gene-activated collagen scaffold up to 21 days. Our results showed wound healing in all groups except in MSC +Jelonet which showed scab formation with exudate. MSC only group healed primarily via fibrotic contraction. In contrast, the scaffold groups showed host tissue integration and a redistribution of extracellular matrix proteins, less contraction, and complete re-epithelized wounds at day 21. The dual GAS displayed programmed wound healing with the greatest neo-vascularization CD31 expression. In conclusion, wound healing in aged rats can be effectively modulated when MSCs are loaded on biocompatible collagen scaffolds, particularly when these scaffolds are loaded with anti-fibrotic and pro-angiogenic factors. This approach enhances blood vessel formation while reducing fibrosis, suggesting a promising potential for programmed wound healing strategies in aged chronic wounds.