Topical Delivery of CNP-miR146a via a Pluronic Lecithin Organogel Enhances Diabetic Wound Healing

Background: Diabetes mellitus is common and associated with numerous complications including diabetic foot ulcers (DFU), which affect a third of patients and are associated with high morbidity and mortality. There are limited pharmacologic treatment options available with mixed efficacy. We have developed a novel therapeutic targeting inflammation and oxidative stress by conjugating microRNA-146a to cerium oxide nanoparticles to create CNP-miR146a and have found that injectable CNP-miR146a is associated with improved wound healing in a diabetic murine model. We hypothesized that a topical formulation of CNP-miR146a would be associated with equivalent improvements in wound healing. Methods: Release tests of CNP conjugated to fluorescein isothiocyanate were performed to determine the optimal gel base for sustained release. Diabetic (db/db) mice were cutaneously wounded and treated with topical CNP-miR146a, empty gel, injectable CNP-miR146a, or injectable phosphate-buffered saline (PBS). Wound healing over time was compared between groups. Histological samples were collected and analyzed for CD45 and CD31 positivity at multiple timepoints. Results: CNP-miR146a in a topical pluronic lecithin organogel (PLO) base was associated with significantly improved wound healing compared to empty gel or injected PBS and equivalent to injected CNP-miR146a. Treatment with CNP-miR146a was also associated with decreased CD45 positivity and increased CD31 positivity, suggesting decreased inflammation and improved angiogenesis. Conclusions: Topical delivery of CNP-miR46a in a PLO base holds significant promise as a potential therapeutic for DFU and may improve patient compliance due to ease of delivery.