No abstract

Thermal burns typically display an injury pattern dictated by the transfer of the thermal energy into the skin and underlying tissues and creation of three zones of injury represented by a necrotic zone of disrupted cells and tissue, an intermediate zone of injured and dying cells, and a distant zone of stressed cells that will recover with proper treatment. The wound healing capabilities of a keratin biomaterial hydrogel were studied in two pilot studies, one using a chemical burn model in mice and the other a thermal burn model in swine. In both studies, keratin was shown to prevent enlargement of the initial wound area and promote faster wound closure. Interestingly, treating thermally stressed dermal fibroblast in culture demonstrated that soluble keratin was able to maintain cell viability and promote proliferation. Separation of so-called alpha and gamma fractions of the keratin biomaterial had differential effects, with the gamma fraction producing more pronounced cell survival and recovery. These results suggest that the gamma fraction, composed essentially of degraded alpha keratin proteins, may facilitate cell rescue after thermal injury. Treatment of burns with gamma keratin may therefore represent a potential therapy for wounds with an intermediate zone of damaged tissue that has the potential to contribute to spontaneous healing.

Partial thickness burns can advance to full thickness after initial injury due to inadequate tissue perfusion and increased production of inflammatory cytokines, which has been referred to as burn wound progression. In previous work, we demonstrated that a keratin biomaterial hydrogel appeared to reduce burn wound progression. In the present study, we tested the hypothesis that a modified keratin hydrogel could reduce burn wound progression and speed healing. Standardized burn wounds were created in Yorkshire swine and treated within 30 minutes with keratin hydrogel (modified and unmodified), collagen hydrogel, or silver sulfadiazine (SSD). Digital images of each wound were taken for area measurements immediately prior to cleaning and dressing changes. Wound tissue was collected and assessed histologically at several time points. Wound area showed a significant difference between hydrogels and SSD groups, and rates of reepithelialization at early time points showed an increase when keratin treatment was used compared to both collagen and SSD. A linear regression model predicted a time to wound closure of approximately 25 days for keratin hydrogel while SSD treatment required 35 days. There appeared to be no measurable differences between the modified and unmodified formulations of keratin hydrogels.