Partial-thickness Burn Wounds Research Articles

728 The Faces of Autologous Skin Cell Suspension as Epidermal Grafts

Abstract Introduction Facial burns are frequently severe and are difficult to skin graft, which may lead to increased morbidity including chronic pain, scarring, and psychosocial stigma. The aim of this study was to describe outcomes of patients with facial burns who received autologous skin cell suspension as an epidermal graft. Methods A retrospective chart review of patients with facial burns admitted to an ABA verified Burn Center from January 2019 to August 2019 was performed. Each patient underwent tangential excision of superficial and deep partial-thickness burn wounds followed by autologous skin cell suspension applied as an epidermal autograft. The wounds were covered with a non-adherent dressing along with bismuth-impregnated, petroleum-based gauze. The dressings were secured in place with sutures to prevent disruption. On post-operative day 6 the dressings were removed with transition to an antimicrobial ointment applied to any remaining open wounds or a moisturizing lotion. Results Five patients, aged 41–89 years, were included. Total body surface ranged from 7–50%. Etiology of the burns included: flame from metal fabricating, assault followed by dousing the patient in gasoline and lighting on fire, flash flame from a water heater explosion, hot oil contact, and involvement in a house fire. 3 of the 5 patients had complete healing noted by post-operative day 6 with excellent results. Two patients required a second excision and application of autologous skin to small portions of the lateral face after healing the majority of the face. One patient developed mild microstomia requiring oral splinting. One of the two patients that required a second application developed ectropian to one of her eyes which was treated with temporary tarsorrhaphy. The second patient that required a second application, died during her hospitalization secondary to complications from her burns and underlying medical co-morbidities. Surviving patients reported satisfaction with the cosmetic outcomes. Conclusions Autologous skin cell suspension as an epidermal graft is a viable option for cosmetically important areas such as the face. This case series provides evidence for its validity when treating partial-thickness burns utilizing the above described protocol in conjunction with a multidisciplinary care team within a burn center. Applicability of Research to Practice By sharing our institutions experience with this relatively new technique we hope to share our positive outcomes as an alternative to stand excision and grafting to areas of significant cosmetic outcomes.

Effects of Hair Follicle Stem Cells on Partial-Thickness Burn Wound Healing and Tensile Strength

Background:The recent improvements in wound healing have led to new strategies in regenerative medicine. Burn wound healing is an important issue in skin regeneration and has multiple indications for stem cell therapy. HFSCs are a highly promising source of stem cells for healing use, as these cells are accessible, active and pluripotent adult stem cells. Methods:HFSCs of the rat whisker were isolated, cultured, and labeled with DiI. Flow cytometry method was used to detect special markers of HFSCs. Deep partial-thickness burn wound was created, and labeled HFSCs were injected around the wound bed. Wound closure was recorded via digital photographs. The inflicted rats were sacrificed at 3, 7, or 14 days post burn and used for subsequent histological and tensiometry analysis. Results:Our results indicated that HFSCs were positive for Nestin and CD34 markers, but negative for Kr15. Morphological and histological photographs revealed that wound closure rate was accelerated in stem cell-treated group compared with other groups. In addition, faster re-epithelialization and collagen deposition were observed. The immunohistochemical analysis suggested that CD31 expression and vascular density enhanced in the stem cell-treated group. Further, tissue tensile strength increased in HFSCs-treated rats in comparison to the control group. Conclusion:The present study demonstrates that HFSCs could accelerate burn wound healing as well as tensile strength in rats.

Preliminary Assessment of Burn Depth by Paper-Based ELISA for the Detection of Angiogenin in Burn Blister Fluid-A Proof of Concept.

Rapid assessment of burn depth is important for burn wound management. Superficial partial-thickness burn (SPTB) wounds heal without scars, but deep partial-thickness burn (DPTB) wounds require a longer healing time and have a higher risk of scar formation. We previously found that DPTB blister fluid displayed a higher angiogenin level than SPTB blister fluid by conventional ELISA. In this study, we developed a paper-based ELISA (P-ELISA) technique for rapid assessment of angiogenin concentration in burn blister fluid. We collected six samples of SPTB blister fluid, six samples of DPTB blister fluid, and seven normal healthy serum samples for analysis. We again chose ELISA to measure and compare angiogenin levels across all of our samples, but we developed a P-ELISA tool and compared sample results from that tool to the results from conventional ELISA. As with conventional ELISA, DPTB blister fluid displayed higher angiogenin levels than SPTB in P-ELISA. Furthermore, our P-ELISA results showed a moderate correlation with conventional ELISA results. This new diagnostic technique facilitates rapid and convenient assessment of burn depth by evaluating a key molecule in burn blister fluid. It presents a novel and easy-to-learn approach that may be suitable for clinically determining burn depth with diagnostic precision.

The Role of Autologous PRP on Deep Partial-Thickness Burn Wound Healing in Bama Pigs.

In this study, we aimed to evaluate the therapeutic effects of autologous platelet-rich plasma (PRP) on deep partial-thickness burns in Bama pigs. Deep partial-thickness burn wounds were created on the back of Bama pigs. The reepithelialization time was compared between the PRP and control groups. The mean score of Ki67 (+) cells and α-SMA (+) vessels, the mean thickness of epidermis and dermis of the healing wounds were determined via H&E staining and immunohistochemical assay. The levels of the growth factors epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), and vascular endothelial growth factor (VEGF) were examined by ELISA. Our data showed that the time to wound reepithelialization was shorter in the PRP group compared with the control group. The thickness of the epidermis was larger in the PRP group compared with the control group. On the 7th and 14th days after the treatment, the mean score of Ki67 (+) cells and α-SMA (+) vessels were higher in the PRP group compared with the control group. The PRP group showed higher levels of growth factors (EGF, bFGF, and VEGF) compared with the control group by ELISA. The results indicated that PRP could improve wound healing process of deep partial-thickness burns in Bama pigs. The PRP increased the thickness of epidermis of the healed wounds, cell proliferation, and angiogenesis. We demonstrated that applying PRP had a greater potential for the treatment of deep partial-thickness burns.

Formulation and Stability Testing of Collagen/PVA Based Silver Sulfadiazine and Basic Fibroblast Growth Factor Incorporated Hydrogel Against Partial Thickness Burn Wounds

Formulation and Stability Testing of Collagen/PVA Based Silver Sulfadiazine and Basic Fibroblast Growth Factor Incorporated Hydrogel Against Partial Thickness Burn Wounds

Mepilex Ag vs. Xeroform in Pediatric Patients That Sustain Partial Thickness Burn Injury

Mepilex Ag vs. Xeroform in Pediatric Patients That Sustain Partial Thickness Burn Injury

Comparison of efficacy of silver-nanoparticle gel, nano-silver-foam and collagen dressings in treatment of partial thickness burn wounds

IntroductionThis study was carried out to compare the efficacy of silver nanoparticle gel (SG), nanosilver foam (SF) and collagen (C) dressings in partial thickness burn wounds. MethodsThis was a single-center, prospective cohort study carried out over a period of 1 year on patients with 15–40% partial thickness thermal burns ≤48 h. Each patient received all three dressings (silver-nanoparticle gel, nanosilver foam, collagen) simultaneously at 3 randomly selected areas which were comparable in terms of burn depth and surface area. Efficacy of the dressings was assessed in terms of healing rates, time taken and ease of application, pain at dressing change, cost, wound-swab culture and scar quality (at 3 months). ResultsA total of 20 patients were included. In SF group, number of patients with 60%–80% re-epithelialization on day10 (SG: 10/20; C: 10/20; SF: 16/20; p = 0.042) and complete healing on day14 (SF: 11/20, C: 6/20, SG: 4/20; p = 0.032) was significantly higher. The time for dressing change was similar at admission (p = 0.918) and day 10 (p = 0.163), although majority of the patients in SF group needed less than 10 min. The time taken (<10 min) was significantly lower in SF group by 14th day (SF: 18/20 C: 6/20 SG: 6/20; p < 0.001). The ease of application rated by clinicians as “extremely easy” was significantly better in SF group (SG: 78%, C: 80%, SF: 95%; p = 0.011). There was a significantly faster decrease in pain scores in SF group by 5th day (VAS score SF: 6, C: 8; SG: 8; p = 0.038), however, pain scores were comparable at 2 weeks. The scar quality (p = 0.82), cost (p = 0.09) and infection rates (SG: 7/20; C: 4/20; SF: 3/20; p = 0.05) were comparable. The need for skin-graft cover was lower in SF group (SG: 5/20; C: 3/20; SF: 1/20). ConclusionNanosilver-foam dressings were found to be more efficacious for re-epithelialization, healing, ease of application, tolerance when compared to silver nanoparticle gel and collagen dressings in partial-thickness burns. All were found to be safe.

Use of NexoBrid for Treatment of Acute Deep Partial and Full Thickness Burn Injuries

Use of NexoBrid for Treatment of Acute Deep Partial and Full Thickness Burn Injuries

Adipose-derived stem cells-induced burn wound healing and regeneration of skin appendages in a novel skin island rat model.

The study of effectiveness of adipose-derived stem cells (ASCs) in treating burn wounds is still a developing field. The process of wound contraction in areas of loose skin is a major confounding factor in the evaluation and study of burn wound healing in animal models. To evaluate the effect of local ASCs administration, deep partial thickness burn wounds were induced by 30 s application of hot copper plates in a novel skin island burn wound rat model to avoid interference from primary wound contraction. Skin islands were divided into two treatment groups-control group (n = 9) injected with PBS and ASCs-treated group (n = 9) injected with 5 × 10 ASCs intradermally. Progress in wound healing was checked at regular intervals after injury (on 1st, 2nd, 3rd, and 4th week) by measuring the mean wound area and analyzing the wound histologically and immunohistochemically, after unstitching the overlaying skin to expose the skin island. It was found that local intradermal injection of ASCs improved burn wound healing at all given time points when compared with control groups, especially in the first 2 weeks (p < 0.05). The percentage of live follicles increased gradually in the ASCs-treated groups compared with control groups between the 3rd and 4th weeks (p < 0.05). The vascular density and proliferating cell nuclear antigen index were also significantly increased in the ASCs-treated groups. Thus, in this study, a novel burn wound rat model with reduced interference from wound contraction has been put forth to investigate the therapeutic effects of local administration of ASCs on burn wound healing. Local injection of ASCs not only improved burn wound recovery but also enhanced angiogenesis and skin appendage regeneration.

Assessment of antioxidant activity of Ocimum sanctum in healing of thermal burn wound with and without supportive treatment of silver sulfadiazine in rabbits

Background: Burns remain a major public health issue all over the world, especially in developing countries. Pseudomonas aeruginosa is a major cause of infection and death in patients with severe burns. So, there is a need to develop drugs which will decrease complications and prevent infections more effectively than the presently used drugs.Methods: Ocimum sanctum, ointment silver sulfadiazine and 24 Rabbits were used in this study. Animals were acclimatized and divided randomly into 04 groups of 06 animals each. After producing partial thickness burn wound ointment silver sulfadiazine was applied daily on the burn wound and Ocimum sanctum was administered orally once daily. Healing was assessed by wound contraction and Oxidative stress and Antioxidant Activity were measured by Malondialdehyde and Superoxide dismutase respectively. Results were analysed by student’s ‘t’ test, one way ANOVA followed by Dennett’s test. P values &lt;0.05 were considered statistically significant.Results: At the end of treatment (After 28th Day) Group treated with ointment silver sulfadiazine+Ocimum sanctum showed maximum Percentage of wound contraction (93.17±4.34), maximum decrease of MDA percentage (0.30±0.02 nmol/ml) and maximum increase of SOD percentage (0.0045±0.0002 IU/gm of Hb).Conclusions: Most effective treatment for burn wound healing in this study was ointment silver sulfadiazine+Ocimum sanctum.

Non-Propellant Foams of Green Nano-Silver and Sulfadiazine: Development and In Vivo Evaluation for Burn Wounds.

A non-propellant based foam (NPF) system was developed incorporating the antibiotics, pectin capped green nano-silver and sulfadiazine (SD) for the topical treatment of burn wounds as a convenient alternative to the existing therapies. NPF were prepared using various surfactants and oils forming a nanoemulsion. Anti-microbial studies by resazurin microtitre assay, ex vivo diffusion, in vivo skin permeation and deposition studies, and acute irritation studies were carried out. NPF was applied onto secondary thermal wounds manifested on mice models followed by macroscopic and histological examinations. NPF had an average globule size of <75nm. The viscosity was ~10cP indicating the feasibility of expulsion from the container upon actuation. With no skin irritation, the foams showed a higher skin deposition of SD. A high contraction and an evident regeneration of the skin tissue upon treatment with NPF indicated a good recovery from the thermal injury was apparent from the histology studies. NPF represents an alternative topical formulation that can be employed as a safe and effective treatment modality for superficial second degree (partial thickness) burn wounds. With a minimal requirement of mechanical force, the no-touch application of NPF makes it suitable for sensitive and irritant skin surfaces.

Developing a Simple Burn Model in Rats of Different Ages.

This article describes a simple and safe model of partial and full thickness burn injury in rats of different ages, which will be essential in our future burn research to explore the age-related mechanism of wound repair and new therapies for burn injuries. A self-made metal column, which was heated in a boiling water bath, was applied for different time periods to the lower back of rats of different ages in burn creation. Wounds were observed visibly at different time points postburn. Biopsies were obtained and examined at 72-hour postburn to determine the depth of burns. The contact durations producing the desired depth of injury in the rat model under constant temperature and pressure were: 3 seconds (deep second degree) and 5 seconds (third degree) in 1-month-old rats; 3 seconds (superficial second degree), 5 seconds (deep second degree), and 7-9 seconds (third degree) in 2-month-old rats; 3-5 seconds (superficial second degree), 7-9 seconds (deep second degree), and 11-13 seconds (third degree) in 12- and 18-month-old rats. This reliable and reproducible experimental model produces consistent burn injuries in rats of different ages by regulating the contact durations, which will help us to understand the underlying pathophysiology of burn injuries and develop novel therapeutic modalities for burn patients of different ages.

Bioactive peptide amphiphile nanofiber gels enhance burn wound healing

BackgroundBurns are physically debilitating and potentially fatal injuries. The standard-of-care for burn wounds is the coverage with gauze dressings designed to minimize trauma to the regenerating epidermis and dermis during dressing changes. However, deep partial- and full-thickness burns always heal slowly when standard wound care alone is performed. We have previously reported that peptide amphiphile (PA) gels, pH-induced self-assembling nanostructured fibrous scaffolds, promote cell proliferation and have great potential in regenerative medicine for rapid repair of tissues. In this study, we hypothesized that the PA gels are capable of accelerating wound healing in burn injury. MethodsArtificially generated thermally damaged fibroblasts and human umbilical vein endothelial cells were seeded onto the various PA nanofiber gels including bioactive and nonbioactive peptide sequences. Cell proliferation was assessed at different time points, and thermally damaged fibroblasts and HUVECs manifested increased proliferation with time when cultured with various PA gels. To determine in vivo effects, burn wounds of rats were treated with the bioactive Arg-Gly-Asp-Ser (RGDS)-modified gel that showed greater cell proliferation in vitro. The wound closure was observed, and skin samples were harvested for histologic evaluation. ResultsCell proliferation using the RGDS-PA gel was significantly higher than that observed in other gels. The RGDS-PA gel significantly enhanced re-epithelialization during the burn wound healing process between days 7 and 28. Application of PA gels accelerates the recovery of deep partial-thickness burn wounds by stimulation of fibroblasts and the creation of an environment conducive to epithelial cell proliferation and wound closure. ConclusionsThis biomaterial represents a new therapeutic strategy to overcome current clinical challenges in the treatment of injuries resulting from burns.

514 Effect of Topical Platelet Rich Plasma on Burn Healing After Partial Thickness Burn Injury

Burn injury has direct impact on local and systemic changes. Many modalities for wound bed preparation was not satisfied. One of the most progressive dressing nowadays is PRP. PRP induces the synthesis of collagen with fibroblast. PRP accelerates wound healing and decrease the use of skin graft. Sixty Wistar albino rats were divided into 3 groups of 20 rats each. Group 1 (platelet-rich plasma group) was exposed to burn injury and topical platelet-rich plasma was applied. Group 2 (control group) was exposed to burn injury and normal saline was applied. Group 3 (blood donor group) was used as blood donors for platelet-rich plasma. Wound was excised on the fourteenth day then fixated in 10% formaldehyde. Specimen was then embedded in parafin block and stained with HE to observe the number of PMN and Masson’s Trichrome to observe collagen deposition. Collagen deposition was found significantly higher in Group 1 (platelet-rich plasma group) (P<0.05). The number of PMN is significantly less in Group 1 (P<0.05) meaning topical PRP also has anti-inflammatory effect. PRP is proven to accelerate burn healing after partial thickness burn injury by increasing the number of collagen deposition also having anti-inflammatory effect shown by the significantly less number of PMN in PRP group. PRP as a new method of burn wound dressing may be able to accelerate wound healing. In large burn area, PRP might help in decreasing the use of skin graft.

36 A Novel Polysaccharide Derivative to Enhance Wound Healing in MRSA-Infected Porcine Partial-Thickness Burn Wound Model

Methicillin-resistant Staphylococcus aureus (MRSA) is the most common etiology of wound infection in the US, leading to considerable morbidity and mortality. SYN01 is a non-toxic, polycationic polysaccharide which disrupts biofilms and prevents bacterial colonization in vitro. It is low cost, stable at room-temperature, and not associated with bacterial resistance. The aim of this study was to investigate the therapeutic potential of SYN01 in MRSA-infected porcine partial-thickness wounds (PTBWs). A total of 4x4cm 30 PTBWs were created on two female Yorkshire pigs and were infected with approximately 108 CFU of MRSA (ATCC® BAA-1717™) on Day 2. Wounds were given 3 days for infection to develop. Starting post-burn day 5, each wound was assigned to one of three treatment groups (n=10 each): no treatment, silvadene (silver sulfadiazine, standard of care), SYN01 rinse and gel. Dressing changes were performed 3 times a week and punch biopsies were taken at each dressing change for bacterial counts using blood-agar plates. Pigs were sacrificed on post-burn day 28. Measured outcomes included percentage of wound closure, bacterial counts and histology. SYN01 topical application lead to a statistically significant wound healing improvement in MRSA-infected partial-thickness burn wounds compared to silvadene treatment and no treatment after day 5 (Figure 1). Application of SYN01 reduced the bacterial count however no statistical significance was reached. Histological wound examination of POD28 demonstrates that wounds treated with SYN01 have healed markedly and are comparable to the healing quality of non-infected burn wounds. SYN01 significantly enhances wound healing in MRSA-infected PTBWs and leads to optimal histological morphology. SYN01 enhances wound healing in PTBWs and is a promising therapeutic option for treating and preventing PTBW infections.

357 Wound Chambers for Porcine Wound Healing Research

Standardized and reproducible animal models are crucial in medical research. Pigs are commonly used in burn wound healing studies because of the large surface area and similarities to human skin. However, the most significant challenge with porcine wound models remains the inability to isolate individual wounds and the high risk of cross-contamination. The aim of this study was to develop wound chambers for burn wound healing research. A porcine partial-thickness burn wound (PTBW) model was first developed by creating 16 burn wounds on the back of a female Yorkshire pig using a brand heated to 200°C and applied with 1kg of force. Different branding durations were attempted (40s, 10s, 5s, or 2s, n=4 per group) to determine the appropriate technique to obtain PTBWs. Biopsies were taken 30 minutes after burning for histology. Wounds were debrided two days later followed by dressing changes three times a week for 14 days to monitor healing was using photographs and tracings. Wound chambers were engineered as a two-piece structure (base and cover) to surround, isolate and cover individual porcine wounds. The wound chamber base was created using a stoma click barrier secured using tissue adhesive, moldable ring seal and staples. The wound chamber cover was created by placing a transparent film dressing over the base’s ring and securing it with a stoma pouch. Based on the first experiment, 15 PTBWs were created on the back of a female Yorkshire pig to test the wound chambers and assess total wound closure, wound contraction, leakage, and cost. In the first pig (PTBW model), the optimal branding time to develop PTBWs was determined clinically and histologically to be 10s showing moderate-to-deep partial-thickness. In the second pig (wound chamber model), the wound chambers were easy to apply and maintain, and were impervious to the pig’s activity. All wounds were closed by week 5 and no wound chamber leakage was observed. The animal tolerated them well. The average cost per wound chamber was $117.20. This study demonstrates that these wound chambers provide a means for controlled monitoring, sampling and treatment of the wound in vivo, allowing a reduction in cross-contamination and an increase in standardization. These wound chambers can be a standardized reproducible model for porcine wound healing research.

Clinical characteristics and treatment of diabetic patients with superficial partial-thickness burn on feet

Objective: To analyze the characteristics and treatment of diabetic patients with superficial partial-thickness burn on feet. Methods: Eighty-three patients with superficial partial-thickness burn on 119 feet were hospitalized in our unit from January 2011 to December 2017. The medical records of the patients with 46 men and 37 women, aged 60±11 were retrospectively analyzed. The patients were divided into diabetes group and non-diabetes group according to whether they had diabetes or not, with 41 patients (60 burn feet) in diabetes group and 42 patients (59 burn feet) in non-diabetes group. Patients in diabetes group and non-diabetes group were given systemic treatment and wound dressing change. Thirty-seven diabetic patients whose wounds deepened to deep partial-thickness were divided into eschar shaving group and non-eschar shaving group according to patients' willingness and the treatment, with 14 patients in eschar shaving group and 23 patients in non-eschar shaving group. Patients in eschar shaving group were given eschar shaving operation at early stage, and patients in non-eschar shaving group were given wound dressing change. The length of hospital stay, hospitalization treatment expenses, pulse of arteria dorsal pedis and posterior tibial artery immediately after admission, deepening of wounds on feet during hospital stay, and rates of wound healing on feet of patients in diabetes group and non-diabetes group were observed and calculated. Pulses of arteria dorsal pedis and posterior tibial artery immediately after admission, deepening of wounds on feet during hospital stay, positive rates of bacteria and fungus in wounds on feet, and rates of wound healing on feet of patients in eschar shaving group and non-eschar shaving group were observed and calculated. Data were processed with chi-square test, t test, Fisher's exact propability method, and Mann-Whitney U test. Results: The length of hospital stay of patients in diabetes group was (29±20) d, which was significantly longer than that of patients in non-diabetes group [(19±13) d, t=2.730, P<0.01]. The hospitalization treatment expense of patients in diabetes group was (46 988±41 322) yuan, which was significantly more than that of patients in non-diabetes group [(29 106±24 813) yuan, t=2.396, P<0.05]. The pulses of arteria dorsal pedis and posterior tibial artery of patients in diabetes group were significantly weaker than those of patients in non-diabetes group (Z=3.278, 2.194, P<0.05 or P<0.01). The percentages of wounds on feet of patients in diabetes group deepening to deep partial-thickness burn, full-thickness skin defect with bone and tendon exposure were respectively 88.3% (53/60) and 23.3% (14/60), which were significantly higher than those of patients in non-diabetes group [47.5% (28/59) and 1.7% (1/59), χ(2)=22.867, 12.644, P<0.01]. Rate of wound healing on feet of patients in diabetes group was 78.3% (47/60), which was significantly lower than 100.0% (59/59) of patients in non-diabetes group ( χ(2)=14.351, P<0.01). There were respectively 21 and 32 feet in patients of eschar shaving group and non-eschar shaving group. There were no significantly statistical differences in pulses of arteria dorsal pedis and posterior tibial artery of patients between eschar shaving group and non-eschar shaving group (Z=0, 0.453, P>0.05). The percentage of wounds on feet of patients in non-eschar shaving group deepening to full-thickness skin defect with bone and tendon exposure was 43.8% (14/32), which was significantly higher than 0 of patients in eschar shaving group ( χ(2)=12.486, P<0.01). Positive rates of bacteria and fungus in wounds on feet of patients in eschar shaving group was significantly lower than that of patients in non-eschar shaving group (χ(2)=4.386, P<0.05 ). Rate of wound healing on feet of patients in non-eschar shaving group was 59.4% (19/32), which was significantly lower than that of patients in eschar shaving group [100.0% (21/21), P<0.01]. Conclusions: Diabetes patients with superficial partial-thickness burn wounds on feet has long length of hospital stay, high hospitalization treatment expenses. Wounds of the patients are easy to deepen, with low wound healing rate. Eschar shaving at early stage when the wounds deepened to deep partial-thickness burn is a good way to increase wound healing rate and prevent further deepening of wounds.

The effect of static magnetic field on partial thickness burn wound healing

The effect of static magnetic field on partial thickness burn wound healing

Nano-silver modified porcine small intestinal submucosa for the treatment of infected partial-thickness burn wounds

Background and aimSilver has been widely used as a topical antimicrobial agent in burn wound care. In a previous study, we demonstrated the introduction of nano-silver particles to porcine small intestinal submucosa (NS-PSIS) led to significant enhancement in antibacterial property in repairing contaminated abdominal defect. In this study, we explored the efficacy of NS-PSIS in the treatment of Pseudomonas aeruginosa-infected partial-thickness burn wounds. Methods48 male Sprague-Dawley rats were divided into four groups of equal number. Standardized and reproducible Pseudomonas aeruginosa-infected partial-thickness thermal burns wound model were created using these rats. NS-PSIS, PSIS (porcine small intestinal submucosa) or lipido-colloid dressingss (Urgotul™) were tested for 14days to assess their ability to heal the rats’ burn wounds. Control group was without any treatment after the establishment of infected burn-wound. The wound contraction rate, animal body weight change, histological examination, and the quantification of IL-6 and C-reactive protein (CRP) were measured to evaluate the healing effects. ResultsNS-PSIS significantly promoted wound healing and recovered the normal growth of rats. There were significantly lower expression levels of pro-inflammatory cytokine (IL-6) and CRP in NS-PSIS group as compared with the PSIS or Urgotul group in the treatment of infected partial-thickness burn wounds. Histological exams revealed significant less inflammatory cells infiltrating, more re-epithelization and neovascularization in NS-PSIS group. There were also less inflammatory cells infiltrations in the major organs in NS-PSIS group. ConclusionsNano-silver modified porcine small intestinal submucosa (NS-PSIS) can be used as a biological derivative dressing for the treatment of infected partial-thickness burn wounds.

Discordance between histologic and visual assessment of tissue viability in excised burn wound tissue

The regenerative capacity of burn wounds, and the need for surgical intervention, depends on wound depth. Clinical visual assessment is considered the gold standard for burn depth assessment but it remains a subjective and inaccurate method for tissue evaluation. The purpose of this study was to compare visual assessment with microscopic and molecular techniques for human burn depth determination, and illustrate differences in the evaluation of tissue for potential regenerative capacity. Using intraoperative visual assessment, patients were identified as having deep partial thickness or full thickness burn wounds. Tangential excisions of burn tissue were processed with hematoxylin and eosin to visualize tissue morphology, lactate dehydrogenase assay to ascertain cellular viability, and Keratin-15 and Ki67 to identify epidermal progenitor cells and proliferative capacity, respectively. RNA from deep partial and full thickness burn tissue as well as normal tissue controls were submitted for RNA sequencing. Lactate dehydrogenase, Keratin-15, and Ki67 were found throughout the excised burn wound tissue in both deep partial thickness burn tissues and in the second tangential excision of full thickness burn tissues. RNA sequencing demonstrated regenerative capacity in both deep partial and full thickness burn tissue, however a greater capacity for regeneration was present in deep partial thickness compared with full thickness burn tissues. In this study, we highlight the discordance that exists between the intraoperative clinical identification of burn injury depth, and microscopic and molecular determination of viability and regenerative capacity. Current methods utilizing visual assessment for depth of injury are imprecise, and can lead to removal of viable tissue. Additionally, hematoxylin and eosin microscopic analysis should not be used as the sole method in research or clinical determination of depth, as there are no differences in staining between viable and nonviable tissue.