644 Enzymatic Debridement of Porcine Burn Wounds via a Novel Protease, SN514

Abstract

Abstract Introduction The future multi-domain battlefield will require prolonged care in theater with evacuation delays of up to seven days. This creates a great risk of infection by not removing any necrotic tissue from burns in a timely manner. Products that can provide non-surgical debridement (NSD) prior to definitive care are essential. The purpose of this study was to evaluate a novel protease (SN514) as a potential NSD agent on deep partial (DPT) and full thickness (FT) burn wounds in a pig and on discarded human skin. Methods On day -4, twenty DPT and FT 3 cm diameter burn wounds were created on the dorsum of 8 anesthetized Yorkshire pigs using appropriate pain control methods. Burns were treated daily from day 0 to day 4 with one of five treatment groups: 1) no treatment, 2) collagenase, 3) 0.5% SN514, 4) 1.0% SN514, or 5) hydrogel vehicle. The wounds were assessed every day, rinsed with 4% chlorohexidine and sterile water, digital and laser speckle images (LSI) were acquired, the treatments reapplied, and then rebandaged. Biopsy strips were harvested across the middle of wounds on day 3 or 4. Samples were paraffin embedded, sectioned, stained with H&E and Masson’s trichrome, and imaged. For the human skin cohort, an abdominoplasty sample was burned to create FT burns. Burned and unburned samples were treated daily with SN514 for up to 4 days. Results During the daily assessment, SN514 treated wounds appeared more debrided than controls. No bleeding, infection, inflammation, or redness were observed. LSI detected significant increases in the perfusion status of SN514 treated wounds for the DPT burns on day 4. Histological analysis indicated a greater debridement of the porcine burn wounds for SN514. Treatment of human burned tissue with SN514 resulted in an 80% weight reduction compared to untreated samples. Conclusions SN514 treatment removed significant amounts of necrotic tissue from DPT and FT burns. SN514 achieved this in the absence of blood loss, without harming adjacent normal skin, and may have potentiated the wounds to allow healing to begin. The observed increase in perfusion after treatments suggests that the wound bed was optimal for spontaneous healing or a temporary covering. Application of SN514 on the burned human tissue successfully debrided both the dermis and hypodermis. Applicability of Research to Practice The ultimate aim is to identify NSD products for prolonged care scenarios that are easy to use, safe, and may improve healing of burns without the need for surgical debridement.