Apyrase: A Portable Treatment to Prevent Burn Progression and Infection

Definitive treatment of burns often requires surgical excision and grafting. However, the facilities and personnel needed for this may not be acutely available in the combat casualty care arena. This creates the need for interim care strategies that would promote healing and prevent infection until more definitive treatment can be provided. Topical apyrase, an adenosine triphosphate (ATP) hydrolyzing enzyme, has local anti-inflammatory and anti-microbial characteristics that proved beneficial in our preliminary studies. For these studies, we hypothesized that topical application of apyrase to burn wounds would reduce inflammation, minimize wound progression, and eliminate infection without local toxicity. In the first aim, we developed a porcine model of partial thickness burn injury to compare the effectiveness of two dosages of apyrase with a standard method of treatment. Serial biopsies, wound measurements and photographs were taken over time to assess inflammation and healing responses. In the second aim, the effects of apyrase as compared to standard of care treatment was evaluated in burn wounds infected with S. aureus and, in separate experiments, A. baumanni. In both aims, the results of wound measurements, histology, and bacterial cultures 21 days after wounding suggested that apyrase, at the chosen dose (1.0-2.0 Units) and frequency (once daily for five days, then once a week), did not have a major effect in this swine model of partial thickness burns. Since early time points and the results from our preliminary studies yielded more promising results, it is possible that higher frequency and more prolonged treatments might prove beneficial in the swine model.