Antigen-Mediated, Macrophage-Stimulated, Accelerated Wound Healing Using α-Gal Nanoparticles.

ABSTRACT

BACKGROUND: Macrophages are known to be crucial to timely and efficacious wound healing. They have been shown to modulate inflammation and the migration and proliferation of regenerative cells, promoting tissue deposition and wound closure. This study explored the use of the natural antigen Galα1-3Galß1-4GlcNAc-R (α-gal), present in lower mammals yet absent in Old World primates and humans, to induce a transiently enhanced macrophage response and thereby direct accelerated wound closure and healing in a standard murine model. METHODS: α1,3galactosyltransferase knockout mice were stimulated to produce anti-Gal antibodies at levels comparable with humans. α-Gal-containing micelle nanoparticles were generated and applied to full-thickness splinted wounds on the mice. At 1, 2, 3, 6, and 9 days postoperatively, mice were killed, and wounds were analyzed histologically for macrophage invasion, epithelialization, vascularization, and granulation tissue deposition. Flow cytometry of wound tissue was performed to quantify relative levels of proinflammatory M1 to anti-inflammatory M2 macrophage subtypes. RESULTS: Treatment of splinted full-thickness murine wounds with α-gal-containing nanoparticles led to accelerated wound healing and closure as demonstrated by accelerated rates of keratinization, vascular growth, and wound tissue deposition. Furthermore, treated wounds demonstrated early and enhanced macrophage invasion, as well as a lower M1-M2 ratio. CONCLUSION: Application of α-gal-containing nanoparticles to wounds stimulated a transiently increased inflammatory response, accelerating the rate of wound healing. Use of α-gal may be a simple and effective way to stimulate the wound healing response in both normal and pathologic wound beds.