Accelerated Burn Healing in a Mouse Experimental Model by α-gal Nanoparticles

Macrophages play a pivotal role in the process of healing burns. One of the major risks in the course of burns healing, in the absence of regenerating epidermis, is infections which greatly contribute to morbidity and mortality in such patients. Therefore, it is widely agreed that accelerating recruitment of macrophages into burns may contribute to faster regeneration of the epidermis and thus, decreasing the risk of infections. This review describes a unique method for rapid recruitment of macrophages into burns and activation of these macrophages to mediate accelerated regrowth of the epidermis and healing of burns. The method is based on application of bio-degradable “alpha-gal” nanoparticles to burns. These nanoparticles present multiple alpha-gal epitopes (Gal alpha1-3Gal beta1-4GlcNAc-R) which bind the abundant natural anti-Gal antibody that constitutes ~1% of immunoglobulins in humans. Anti-Gal/alpha-gal nanoparticles interaction activates the complement system, resulting in localized production of the complement cleavage-peptides C5a and C3a that are highly effective chemotactic factors for monocytes derived macrophages. The macrophages recruited into the alpha-gal nanoparticles treated burns are activated following interaction between the Fc portion of anti-Gal coating the nanoparticles and the multiple Fc receptors on macrophages cell membranes. The activated macrophages secrete a variety of cytokines/growth factors that accelerate the regrowth of the epidermis and regeneration of the injured skin, thereby cutting the healing time by half. Studies on healing of thermal injuries in the skin of anti-Gal producing mice, demonstrated a much faster recruitment of macrophages into burns treated with alpha-gal nanoparticles than in control burns treated with saline and healing of the burns within 6 days, whereas healing of control burns takes ~12 days. alpha-Gal nanoparticles are non-toxic, and do not cause chronic granulomas or keloids. These findings suggest that alpha-gal nanoparticles treatment may harness anti-Gal for inducing similar accelerated burn healing effects also in humans.