One of the promising approaches to facilitate healing and regenerative capacity includes the application of growth-factor-loaded biomaterials. Human platelet lysate (hPL) derived from platelet-rich plasma through a freeze-thaw process has been used as a growth factor rich therapeutic in many regenerative applications. To provide sustained local delivery of the hPL-derived growth factors such as epidermal growth factor (EGF), the hPL can be loaded into biomaterials that do not degrade rapidly in vivo. Keratin (KSO), a strong filamentous protein found in human hair, when formulated as a hydrogel, is shown to sustain the release of drugs and promote wound healing. In the current study, we created a KSO biomaterial that spontaneously forms a hydrogel when rehydrated with hPL that is capable of controlled and sustained release of pro-regenerative molecules. Our study demonstrates that the release of hPL is controlled by changing the KSO hydrogel and hPL-loading concentrations, with hPL loading concentrations having a greater effect in changing release profiles. In addition, the 15% KSO concentration proved to form a stable hydrogel, and supported cell proliferation over 3 days without cytotoxic effects in vitro. The hPL-loaded keratin hydrogels show promise in potential applications for wound healing with the sustained release of pro-regenerative growth factors with easy tailoring of hydrogel properties.

Introduction Burns are common injuries on the battlefield. Given austere environments, surgical debridement of injured service members is often not feasible in these settings. Delays in surgical debridement create a risk of infection and deranged healing for burn patients. As such, this study attempts to identify the best commercially available off-the-shelf (OTS) therapies with field-deployable potential to improve prolonged field care (PFC) of burn-injured soldiers. Methods Deep partial-thickness (DPT) burns (25 cm2) were created on the dorsum of 5 anesthetized pigs utilizing a thermocouple burn device at 100°C for 15 seconds. Nonsurgical debridement was done 1-hour after burn creation using sterile saline water and gauze to remove excess eschar tissue. Animals were then randomized into 5 experimental groups, and OTS therapies were applied to 6 of the 12 created DPT burns. The remaining 6 burns were treated with 1% silver sulfadiazine cream (Ascend Laboratories, LLC, Parsippany, NJ) as the PFC standard of care (SOC) controls. The 5 randomized OTS therapies were: irradiated sterile human skin allograft (IHS), biodegradable temporizing matrix (BTM), polylactic acid skin substitute, hyaluronic acid ester matrix (HAM), and decellularized fish skin graft (FSG). Wounds were serially assessed on post-burn days 3, 7, 14, 21, and 28. Assessments were conducted using a combination of photographs, histology, and quantitative bacteriology. Endpoints included burn wound progression, re-epithelialization, wound contraction, scar elevation index, and colony-forming units (CFU). Results The analysis demonstrated that by day 3, the FSG prevented burn wound progression the most efficiently. In terms of wound healing, the results showed re-epithelialization percentages close to 100% by day 28 for all treatment groups. No statically significant differences were observed. Quality of healing analyses demonstrated that the BTM-treated wounds had contracted less and the difference to the IHS-treated wounds was statistically significant (P < .05). As regards to antimicrobial properties, the CFU results showed no statistically significant differences between the OTS therapies and the SOC on days 3, 7, and 14. Conclusions The impact of Food and Drug Administration-approved OTS therapies was compared to the current PFC SOC for the treatment of DPT burns in a porcine model. Several topical options exist for the management of burns prior to definitive treatment in the operating room and warrant further evaluation. These therapies are actively used on civilian burn counterparts and have far-forward, field-deployable potential for use at the point of injury so that injured service members may not need evacuation to higher roles of care and combat power may be preserved. Our results demonstrated that all the studied OTS therapies performed well when compared to the SOC in terms of burn wound progression, wound healing, quality of healing, and quantitative bacteriology.

Introduction Skin grafting of poorly vascularized wound beds, (e.g. exposed fascia, tendon, or bone) is often a multi-stage procedure, resulting in persistent open wounds and long-term complications such as scarring and contracture. Single-stage skin replacement could mitigate these downsides. Here we present the addition of topical nutrients and negative-pressure wound therapy (NPWT) + saline instill to improve graft take, and a case report of treatment of a non-healing wound in a single-stage procedure. Methods Ex vivo, STSGs (12/1000ths in) were harvested from swine (Sus scrofa domestica) post-euthanasia and transferred into wells with distilled water, PBS, Tyrode’s Buffer, high (4.5g/L) and low (2g/L) glucose DMEM, EpiLife, or William’s E (WE) media for 7 days, followed by performance of biochemical analyses and immunohistochemistry. In vivo, 20 full-thickness 5cm-diameter excisional wounds on the dorsum of two anesthetized swine were treated with dermal substitutes (DS, 0.4mm, 0.8mm, 1.2mm, or 1.6mm thickness), STSG, and NPWT with or without intermittent saline instill (3x daily, 300mL, 15-minute soak). Re-epithelialization was assessed at day 7 and 14. Lastly, a chronic 800cm2 left knee wound was treated with NPWT + instill (every 3.5 hours, 80mL, 10-minute soak, 3-day duration) over a 12/1000ths inch STSG. Results DMEM with high glucose (DMEM-HG) and WE produced the most lactic acid and enzymatic carbonate. Lactate dehydrogenase activity was lowest with WE. DMEM-HG had the highest glucose consumption but the most unconsumed glucose, with WE resulting in the next highest amount. Immunohistochemistry showed DMEM-HG or WE had the most dividing and least dying cells. In the porcine model, DS of 0.8mm, 1.2mm, and 1.6mm thicknesses inhibited graft take significantly (p< 0.01, p=0.02, p< 0.01, respectively) for all NPWT alone wounds. Addition of saline instill showed significant improvement in graft take (p=0.03) for 0.8mm DS wounds. 1.2mm and 1.6mm DS wounds continued to show significantly decreased graft take (p=0.03 and p=0.02, respectively). All 0.4mm DS wounds performed similar to control. Clinically, following NPWT removal on post-op day 3, almost complete STSG take was observed without exudate, pus, or malodor within the wound bed. Conclusions While additional studies are ongoing to determine the optimal nutrient supplementation, WE performed the best overall thus far. In vivo, 0.8mm DS created a successful model of a poorly vascularized wound bed, as NPWT + instill overcame this thickness. The novel use of NPWT + instill treatment over STSG clinically shows promise to improve graft take in the future.