A Review of the Local Pathophysiologic Bases of Burn Wound Progression:

Clinical effectiveness, quality of life and cost-effectiveness of Flaminal® versus Flamazine® in the treatment of partial thickness burns: study protocol for a randomized controlled trial

Background

Partial thickness burns are painful, difficult to manage and can have a negative effect on quality of life through scarring, permanent disfigurement and loss of function. The aim of burn treatment in partial thickness burns is to save lives, stimulate wound healing by creating an optimumly moist wound environment, to have debriding and analgesic effects, protect the wound from infection and be convenient for the patient and caregivers. However, there is no consensus on the optimal treatment of partial thickness wounds. Flaminal® and Flamazine® are two standard treatment options that provide the above mentioned properties in burn treatment. Nevertheless, no randomized controlled study has yet compared these two common treatment modalities in partial thickness burns. Thus, the aim of this study is to evaluate the clinical effectiveness, quality of life and cost-effectiveness of Flaminal® versus Flamazine® in the treatment of partial thickness burns.

Methods/Design

In this two-arm open multi-center randomized controlled trial, 90 patients will be randomized between Flaminal® and Flamazine® and followed for 12 months. The study population will consist of competent or temporarily non-competent (because of sedation and/or intubation) patients, 18 years of age or older, with acute partial thickness burns and a total body surface area (TBSA) of less than 30 %. The main study outcome is time to complete re-epithelialization (greater than 95 %). Secondary outcome measures include need for grafting, wound colonization/infection, number of dressing changes, pain and anxiety, scar formation, health-related quality of life (HRQoL), and costs.

Discussion

This study will contribute to the optimal treatment of patients with partial thickness burn wounds and will provide evidence on the (cost-)effectiveness and quality of life of Flaminal® versus Flamazine® in the treatment of partial thickness burns.

Trial registration

Netherlands Trial Register NTR4486, registered on 2 April 2014.

Far-infrared promotes burn wound healing by suppressing NLRP3 inflammasome caused by enhanced autophagy

Understanding the underlying molecular mechanisms in burn wound progression is crucial to providing appropriate diagnoses and designing therapeutic regimens for burn patients. When inflammation becomes unregulated, recurrent, or excessive, it interferes with burn wound healing. Autophagy, which is a homeostatic and catabolic degradation process, was found to protect against ischemic injury, inflammatory diseases, and apoptosis in some cases. In the present study, we investigated whether far-infrared (FIR) could ameliorate burn wound progression and promote wound healing both in vitro and in a rat model of deep second-degree burn. We found that FIR induced autophagy in differentiated THP-1 cells (human monocytic cells differentiated to macrophages). Furthermore, FIR inhibited both the NLRP3 inflammasome and the production of IL-1β in lipopolysaccharide-activated THP-1 macrophages. In addition, FIR induced the ubiquitination of ASC, which is the adaptor protein of the inflammasome, by increasing tumor necrosis factor receptor-associated factor 6 (TRAF6), which is a ubiquitin E3 ligase. Furthermore, the exposure to FIR then promoted the delivery of inflammasome to autophagosomes for degradation. In a rat burn model, FIR ameliorated burn-induced epidermal thickening, inflammatory cell infiltration, and loss of distinct collagen fibers. Moreover, FIR enhanced autophagy and suppressed the activity of the NLRP3 inflammasome in the rat skin tissue of the burn model. Based on these results, we suggest that FIR-regulated autophagy and inflammasomes will be important for the discovery of novel therapeutics to promote the healing of burn wounds.

KEY MESSAGES

Far-infrared (FIR) induced autophagy in THP-1 macrophages. FIR suppressed the NLRP3 inflammasome through the activation of autophagy. FIR induced the ubiquitination of ASC by increasing TRAF6. FIR ameliorated burn wound progression and promoted wound healing in a rat burn model.

Seawater Immersion Aggravates Burn Injury Causing Severe Blood Coagulation Dysfunction

This study aimed to investigate the endothelial function in a canine model of burn injury combined with seawater immersion. The model of burn injury was established. The dogs were randomly divided into four groups including dogs with burn injury (B group), or burn injury combined with seawater immersion (BI group), or only immersion in seawater (I group), or control animals with no injury or immersion (C group). The circulating endothelial cell (CEC) count and coagulation-fibrinolysis parameters were measured. The CEC count in B group increased at 4 h, 7 h, and 10 h after injury and then reduced, whereas it continuously increased to a greater extent in BI group (P < 0.05). The von Willebrand factor (vWF) activity, plasminogen activator inhibitor (PAI-1), and the ratio of thromboxane B2 (TXB₂) to 6-keto-prostaglandin F1α (6-K-PGF_1α) in BI group had a marked increase after injury, and the tissue-type plasminogen activator (tPA) in the BI group decreased. Microscope observations revealed thrombus formation in lungs of the animals in BI group, but not in C, I, or B groups. Burn injury causes endothelial dysfunction, and seawater immersion lastingly aggravates this injury, leading to a higher risk of developing thrombosis.

The Role of Necroptosis in Burn Injury Progression in a Rat Comb Burn Model

OBJECTIVES

Progression of cell death after burn injury may occur by one of three mechanisms: passive necrosis, apoptosis, and programmed necroptosis that requires the receptor-interacting protein kinase-3 (RIP-3). The hypothesis was that RIP-3 is present in normal and burned skin; that necroptosis plays a role in burn injury progression; and that treatment with necrostatin-1, an inhibitor of necroptosis, would reduce burn progression.

METHODS

Skin specimens from rats were examined for the presence of RIP-3. Using a 150-g brass comb preheated to 100°C, we created two comb burns (one on each side) consisting of four rectangular burns, separated by three unburned interspaces, on both sides of the backs of anesthetized male Sprague-Dawley rats (240 to 300 g). The interspaces represent the ischemic zones surrounding the central necrotic core. Left untreated, these areas undergo necrosis. In the first experiment, 10 rats each were randomized to 1.65 mg/kg necrostatin-1 or control given by intraperitoneal injection 1 hour after injury. In the second experiment, 10 rats each were randomized to two intravenous injections of 1.65 mg/kg necrostatin-1 or its vehicle at 1 and 4 hours after injury. The primary outcome was the percentage of interspaces undergoing necrosis within 7 days of injury. Binary data were compared with chi-square or Fishers' exact tests.

RESULTS

All normal and burned skin specimens from rats stained positive for RIP-3. In the first experiment, nearly all unburned interspaces in both the experimental and the control rats underwent necrosis (47 of 48, 97.9% vs. 48 of 48, 100%; p = not significant [NS]). Similarly, in the second experiment, there was no difference in the percentage of unburned interspaces undergoing necrosis within 7 days of injury in rats treated with two doses of necrostatin-1 or the control vehicle (46 of 48, 95.8% vs. 48 of 48, 100%; p = NS). There were no wound infections noted in rats injected with necrostatin-1.

CONCLUSIONS

The skin of rats contains RIP-3 necessary for necroptosis. Injection of rats with either a single intraperitoneal dose or two intravenous doses of necrostatin-1 failed to reduce burn injury progression in a rat comb burn model. This may be due to inactivity of necrostatin-1 or the lack of a role of necroptosis in burn injury progression in the rat comb burn model.

Topically applied metal chelator reduces thermal injury progression in a rat model of brass comb burn

Oxidative stress may be involved in the cellular damage and tissue destruction as burn wounds continues to progress after abatement of the initial insult. Since iron and calcium ions play key roles in oxidative stress, this study tested whether topical application of Livionex formulation (LF) lotion, that contains disodium EDTA as a metal chelator and methyl sulfonyl methane (MSM) as a permeability enhancer, would prevent or reduce burns.

METHODS

We used an established brass comb burn model with some modifications. Topical application of LF lotion was started 5 min post-burn, and repeated every 8 h for 3 consecutive days. Rats were euthanized and skin harvested for histochemistry and immunohistochemistry. Formation of protein adducts of 4-hydroxynonenal (HNE), malonadialdehyde (MDA) and acrolein (ACR) and expression of aldehyde dehydrogenase (ALDH) isozymes, ALDH1 and ALDH2 were assessed.

RESULTS

LF lotion-treated burn sites and interspaces showed mild morphological improvement compared to untreated burn sites. Furthermore, the lotion significantly decreased the immunostaining of lipid aldehyde-protein adducts including protein -HNE, -MDA and -ACR adducts, and restored the expression of aldehyde dehydrogenase isozymes in the unburned interspaces.

CONCLUSION

This data, for the first time, demonstrates that a topically applied EDTA-containing lotion protects burns progression with a concomitant decrease in the accumulation of reactive lipid aldehydes and protection of aldehyde dehydrogenase isozymes. Present studies are suggestive of therapeutic intervention of burns by this novel lotion.

Utilization of Glycosaminoglycans/Proteoglycans as Carriers for Targeted Therapy Delivery

The outcome of patients with cancer has improved significantly in the past decade with the incorporation of drugs targeting cell surface adhesive receptors, receptor tyrosine kinases, and modulation of several molecules of extracellular matrices (ECMs), the complex composite of collagens, glycoproteins, proteoglycans, and glycosaminoglycans that dictates tissue architecture. Cancer tissue invasive processes progress by various oncogenic strategies, including interfering with ECM molecules and their interactions with invasive cells. In this review, we describe how the ECM components, proteoglycans and glycosaminoglycans, influence tumor cell signaling. In particular this review describes how the glycosaminoglycan hyaluronan (HA) and its major receptor CD44 impact invasive behavior of tumor cells, and provides useful insight when designing new therapeutic strategies in the treatment of cancer.

Utility of spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI) to non-invasively diagnose burn depth in a porcine model

Surgical intervention of second degree burns is often delayed because of the difficulty in visual diagnosis, which increases the risk of scarring and infection. Non-invasive metrics have shown promise in accurately assessing burn depth. Here, we examine the use of spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI) for predicting burn depth. Contact burn wounds of increasing severity were created on the dorsum of a Yorkshire pig, and wounds were imaged with SFDI/LSI starting immediately after-burn and then daily for the next 4 days. In addition, on each day the burn wounds were biopsied for histological analysis of burn depth, defined by collagen coagulation, apoptosis, and adnexal/vascular necrosis. Histological results show that collagen coagulation progressed from day 0 to day 1, and then stabilized. Results of burn wound imaging using non-invasive techniques were able to produce metrics that correlate to different predictors of burn depth. Collagen coagulation and apoptosis correlated with SFDI scattering coefficient parameter [Formula: see text] and adnexal/vascular necrosis on the day of burn correlated with blood flow determined by LSI. Therefore, incorporation of SFDI scattering coefficient and blood flow determined by LSI may provide an algorithm for accurate assessment of the severity of burn wounds in real time.

Beneficial effects of hydrogen-rich saline on early burn-wound progression in rats

Introduction

Deep burn wounds undergo a dynamic process known as wound progression that results in a deepening and extension of the initial burn area. The zone of stasis is more likely to develop more severe during wound progression in the presence of hypoperfusion. Hydrogen has been reported to alleviate injury triggered by ischaemia/reperfusion and burns in various organs by selectively quenching oxygen free radicals. The aim of this study was to investigate the possible protective effects of hydrogen against early burn-wound progression.

Methods

Deep-burn models were established through contact with a boiled, rectangular, brass comb for 20 s. Fifty-six Sprague-Dawley rats were randomly divided into sham, burn plus saline, and burn plus hydrogen-rich saline (HS) groups with sacrifice and analysis at various time windows (6 h, 24 h, 48 h) post burn. Indexes of oxidative stress, apoptosis and autophagy were measured in each group. The zone of stasis was evaluated using immunofluorescence staining, ELISA, and Western blot to explore the underlying effects and mechanisms post burn.

Results

The burn-induced increase in malondialdehyde was markedly reduced with HS, while the activities of endogenous antioxidant enzymes were significantly increased. Moreover, HS treatment attenuated increases in apoptosis and autophagy postburn in wounds, according to the TUNEL staining results and the expression analysis of Bax, Bcl-2, caspase-3, Beclin-1 and Atg-5 proteins. Additionally, HS lowered the level of myeloperoxidase and expression of TNF-α, IL-1β, and IL-6 in the zone of stasis while augmenting IL-10. The elevated levels of Akt phosphorylation and NF-κB p65 expression post burn were also downregulated by HS management.

Conclusion

Hydrogen can attenuate early wound progression following deep burn injury. The beneficial effect of hydrogen was mediated by attenuating oxidative stress, which inhibited apoptosis and inflammation, and the Akt/NF-κB signalling pathway may be involved in regulating the release of inflammatory cytokines.

Early Intervention for Low-Temperature Burns: Comparison between Early and Late Hospital Visit Patients

Background

Various focal heating devices are popular in Korea under the cultural influence of the traditional ondol under-floor method of home heating. These devices can cause severe burn-like injuries resulting from device malfunction or extended with low heat contact. In addition to injuries under these high heat contact, burns can be occurred by low heat exposure with prolonged periods despite the devices are properly functioning. In order to develop strategies to reduce the duration of periods of illness due to low-temperature burns, we analyzed and compared treatment methods and therapeutic periods for this type of injury.

Methods

This retrospective study included 43 patients burned under low heat conditions. Patients were divided into an operative group and a conservative group. The patients in the operative group underwent at least one surgical excision, and were further subdivided into early and late visit groups. The conservative group was treated only with dressings. We compared the treatment periods between the operative group and the conservative group, and also compared the preparation periods and treatment periods between the two operative groups.

Results

The average treatment period was significantly shorter in the operative group (P=0.02). In the early visit operative group, both wound preparation and treatment were briefer than in the late visit group.

Conclusions

We recommend that early proper burn care and early surgical intervention, including appropriate excision, are feasible ways to reduce the treatment period of low-temperature burn patients.

An artificial HSE promoter for efficient and selective detection of heat shock pathway activity

Detection of cellular stress is of major importance for the survival of cells. During evolution, a network of stress pathways developed, with the heat shock (HS) response playing a major role. The key transcription factor mediating HS signalling activity in mammalian cells is the HS factor HSF1. When activated it binds to the heat shock elements (HSE) in the promoters of target genes like heat shock protein (HSP) genes. They are induced by HSF1 but in addition they integrate multiple signals from different stress pathways. Here, we developed an artificial promoter consisting only of HSEs and therefore selectively reacting to HSF-mediated pathway activation. The promoter is highly inducible but has an extreme low basal level. Direct comparison with the HSPA1A promoter activity indicates that heat-dependent expression can be fully recapitulated by isolated HSEs in human cells. Using this sensitive reporter, we measured the HS response for different temperatures and exposure times. In particular, long heat induction times of 1 or 2 h were compared with short heat durations down to 1 min, conditions typical for burn injuries. We found similar responses to both long and short heat durations but at completely different temperatures. Exposure times of 2 h result in pathway activation at 41 to 44 °C, whereas heat pulses of 1 min lead to a maximum HS response between 47 and 50 °C. The results suggest that the HS response is initiated by a combination of temperature and exposure time but not by a certain threshold temperature.

Noninvasive imaging technologies for cutaneous wound assessment: A review

The ability to phenotype wounds for the purposes of assessing severity, healing potential and treatment is an important function of evidence-based medicine. A variety of optical technologies are currently in development for noninvasive wound assessment. To varying extents, these optical technologies have the potential to supplement traditional clinical wound evaluation and research, by providing detailed information regarding skin components imperceptible to visual inspection. These assessments are achieved through quantitative optical analysis of tissue characteristics including blood flow, collagen remodeling, hemoglobin content, inflammation, temperature, vascular structure, and water content. Technologies that have, to this date, been applied to wound assessment include: near infrared imaging, thermal imaging, optical coherence tomography, orthogonal polarization spectral imaging, fluorescence imaging, laser Doppler imaging, microscopy, spatial frequency domain imaging, photoacoustic detection, and spectral/hyperspectral imaging. We present a review of the technologies in use or development for these purposes with three aims: (1) providing basic explanations of imaging technology concepts, (2) reviewing the wound imaging literature, and (3) providing insight into areas for further application and exploration. Noninvasive imaging is a promising advancement in wound assessment and all technologies require further validation.

Considerations on the use of platelet-rich plasma, specifically for burn treatment

Platelet-rich plasma (PRP) is a fraction of blood plasma with a platelet concentration above baseline. After activation of the platelets, growth factors are released, which are involved in wound-healing processes. Application of a multitude of growth factors seems to boost the healing process. In this review the authors provide a comprehensive overview of the many different aspects of PRP; this is followed by a short outline of the evidence for a wide range of applications and finally narrowing down to a more in-depth analysis of the literature on the potential use of PRP in burn treatment. The authors performed an extensive search on PRP and the different biological, as well as practical aspects for the different applications. Furthermore, we performed a systematic search on PRP in the treatment of burn wounds. A high variety exists in PRP products, procedures, and content. This makes interpretation and comparison of the evidence difficult. PRP has been reported to have beneficial effects on wound healing in different fields of surgery and in the treatment of acute, chronic, and diabetic wounds. Literature on the use of PRP in burns is scarce. Separate growth factors have shown beneficial results in the treatment of burns. Furthermore, an animal study and several case reports showed improved burn wound-healing time after the application of PRP. A deep dermal burn could benefit from PRP through its hemostatic antimicrobial abilities and the positive effects seen in wound healing. However, burn patients have an altered physiological state and it is unknown how this may affect platelet function and quality. Furthermore, the effect of PRP on scarring has not been evaluated properly. Future research is needed to elucidate the role of PRP in the treatment of burns.

Using skin for drug delivery and diagnosis in the critically ill

Skin offers easy access, convenience and non-invasiveness for drug delivery and diagnosis. In principle, these advantages of skin appear to be attractive for critically ill patients given potential difficulties that may be associated with oral and parenteral access in these patients. However, the profound changes in skin physiology that can be seen in these patients provide a challenge to reliably deliver drugs or provide diagnostic information. Drug delivery through skin may be used to manage burn injury, wounds, infection, trauma and the multisystem complications that rise from these conditions. Local anaesthetics and analgesics can be delivered through skin and may have wide application in critically ill patients. To ensure accurate information, diagnostic tools require validation in the critically ill patient population as information from other patient populations may not be applicable.

Quantitative assessment of graded burn wounds in a porcine model using spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI)

Accurate and timely assessment of burn wound severity is a critical component of wound management and has implications related to course of treatment. While most superficial burns and full thickness burns are easily diagnosed through visual inspection, burns that fall between these extremes are challenging to classify based on clinical appearance. Because of this, appropriate burn management may be delayed, increasing the risk of scarring and infection. Here we present an investigation that employs spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI) as non-invasive technologies to characterize in-vivo burn severity. We used SFDI and LSI to investigate controlled burn wounds of graded severity in a Yorkshire pig model. Burn wounds were imaged starting at one hour after the initial injury and daily at approximately 24, 48 and 72 hours post burn. Biopsies were taken on each day in order to correlate the imaging data to the extent of burn damage as indicated via histological analysis. Changes in reduced scattering coefficient and blood flow could be used to categorize burn severity as soon as one hour after the burn injury. The results of this study suggest that SFDI and LSI information have the potential to provide useful metrics for quantifying the extent and severity of burn injuries.

The effect of controlled mild hypothermia on large scald burns in a resuscitated rat model

OBJECTIVE

Early surface cooling of burns reduces pain, depth of injury and improves healing. We hypothesized that controlled mild hypothermia would also prolong survival in a fluid resuscitated rat model of large scald burns.

METHODS

Forty rats were anesthetized and a single full-thickness scald burn covering 40% of total body surface area was created on each of the rats. The rats were then randomized to hypothermia (n=20) or no hypothermia (n=20). Mild hypothermia (a reduction of 2°C) was induced with intraperitoneal 4°C normal saline and ice packs. After 2 hours of hypothermia, the rats were rewarmed back to their baseline temperature with a heating pad. The control rats received room temperature intraperitoneal saline. The difference in survival between the groups was determined using Kaplan-Meier analysis and the log-rank test.

RESULTS

Hypothermia was induced in all experimental rats within a mean of 22 minutes (95% confidence interval, 17 to 27). The number of normothermic and hypothermic rats that expired at each time interval were: at 1 hour, 4 vs. 0; at 10 hours, 2 from each group; at 24 hours, 0 vs. 1; at 48 hours, 2 vs. 2; at 72 hours, 1 vs. 1; and at 120 hours, 1 vs. 1 respectively. There were no differences in time to survival between the groups.

CONCLUSION

Induction of brief, mild hypothermia does not prolong survival in a resuscitated rat model of large scald burns.

The evaluation and management of thermal injuries: 2014 update

Burns are among the most common injuries presenting to the emergency department. While burns, especially large ones, may be associated with significant morbidity and mortality, most are minor and can be managed by emergency practitioners and discharged home with close follow-up. In contrast, patients with large burns require aggressive management of their airway, breathing and circulation in order to reduce mortality and morbidity. While early endotracheal intubation of patients with actual or impending airway compromise and aggressive fluid resuscitation have been emphasized, it appears that the pendulum may have swung a bit too far towards the extreme. The current review will briefly cover the epidemiology, pathogenesis and diagnosis of burn injuries with greater emphasis on airway and fluid management. We will also discuss the local management of the burn wound, which is all that is required for most burn patients in the emergency department.

The Composition and Biological Activity of Honey: A Focus on Manuka Honey

Honey has been used as a food and medical product since the earliest times. It has been used in many cultures for its medicinal properties, as a remedy for burns, cataracts, ulcers and wound healing, because it exerts a soothing effect when initially applied to open wounds. Depending on its origin, honey can be classified in different categories among which, monofloral honey seems to be the most promising and interesting as a natural remedy. Manuka honey, a monofloral honey derived from the manuka tree (Leptospermum scoparium), has greatly attracted the attention of researchers for its biological properties, especially its antimicrobial and antioxidant capacities. Our manuscript reviews the chemical composition and the variety of beneficial nutritional and health effects of manuka honey. Firstly, the chemical composition of manuka honey is described, with special attention given to its polyphenolic composition and other bioactive compounds, such as glyoxal and methylglyoxal. Then, the effect of manuka honey in wound treatment is described, as well as its antioxidant activity and other important biological effects.

Growth factor therapy in patients with partial-thickness burns: a systematic review and meta-analysis

Growth factor (GF) therapy has shown promise in treating a variety of refractory wounds. However, evidence supporting its routine use in burn injury remains uncertain. We performed this systematic review and meta-analysis assessing randomised controlled trials (RCTs) to investigate efficacy and safety of GFs in the management of partial-thickness burns. Electronic searches were conducted in PubMed and the Cochrane databases. Endpoint results analysed included wound healing and scar formation. Thirteen studies comprising a total of 1924 participants with 2130 wounds (1131 GF receiving patients versus 999 controls) were identified and included, evaluating the effect of fibroblast growth factor (FGF), epidermal growth factor (EGF) and granulocyte macrophage-colony stimulating factor (GM-CSF) on partial-thickness burns. Topical application of these agents significantly reduced healing time by 5·02 (95% confidence interval, 2·62 to 7·42), 3·12 (95% CI, 1·11 to 5·13) and 5·1 (95% CI, 4·02 to 6·18) days, respectively, compared with standard wound care alone. In addition, scar improvement following therapy with FGF and EGF was evident in terms of pigmentation, pliability, height and vascularity. No significant increase in adverse events was observed in patients receiving GFs. These results suggested that GF therapy could be an effective and safe add-on to standard wound care for partial-thickness burns. High-quality, adequately powered trials are needed to further confirm the conclusion.

Burn care in disaster and other austere settings

In some circumstances, burn care must be delivered in a simple manner without the luxury of modern resources. Such circumstances include care in low- and middle-income countries, war zones, and mass casualty incidents. Triage decisions need to be made carefully, allowing the focus of limited personnel and equipment on those most likely to survive. Simple techniques can be used to help many burn victims, such as utilizing oral resuscitation formulas for burn resuscitation. Although even the best attempts at preparation often fall short, there are many benefits from planning and training.

Role of autophagy and apoptosis in wound tissue of deep second-degree burn in rats

OBJECTIVES

The pathogenesis of burn wound progression is poorly understood. Contributing factors include continuous loss of blood perfusion, excessive inflammation, and elevated apoptosis levels in wound tissue. Macroautophagy (here referred to simply as "autophagy") is associated with many chronic diseases. The authors hypothesized that autophagy is involved in burn wound progression in a rat model of deep second-degree burn.

METHODS

Deep second-degree burns were modeled using a brass rod heated to 100°C applied for 6 seconds to the back skin of Wistar rats. Full-thickness biopsies were obtained from burned and nonburned controls at several times postburn. Western blotting and immunohistochemical (IHC) staining determined expression of the autophagy markers Light Chain 3 (LC3) and beclin-1. Apoptosis was determined by terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) assay and laser Doppler flowmetry (LDF)-measured tissue perfusion. Myeloperoxidase (MPO) activity assay measured inflammation. Hematoxylin and eosin (H&E) and Masson's trichrome staining-determined pathology and wound depth.

RESULTS

The LC3 and beclin-1 protein level in burn wounds decreased to one-fourth of normal levels (p<0.01) over 24 hours and then began to increase but still did not reach their normal level. TUNEL-positive cells in burn wounds were 3.7-fold (p<0.01) elevated over 48 hours and then decreased slightly, yet still remained higher than in normal skin. The burn wound progressed in depth over 72 hours. In addition, significant decrease in LDF values and upregulation of MPO activity were observed. Enhanced LC3-positive cells were observed in the deep dermal layer of burn wounds as shown by IHC staining.

CONCLUSIONS

A reduction in autophagy and blood flow and an increase in apoptosis and inflammation were observed in burn wounds early during the course of burn injury progression. This suggests that autophagy, complemented by apoptosis, play important roles in burn progression. Enhanced autophagy in the deep dermis may be a prosurvival mechanism against ischemia and inflammation after burn injury.

Fibronectin peptides that bind PDGF-BB enhance survival of cells and tissue under stress

Stressors after injury from a multitude of factors can lead to cell death. We have identified four fibronectin (FN) peptides: two from the first FN type III repeat (FNIII1), one from the 13th FN type III repeat (FNIII13), and one from FN variable region (IIICS), which when tethered to a surface acted as platelet-derived growth factor-BB (PDGF-BB) enhancers to promote cell survival. One of the FNIII1 peptides and its smallest (14-mer) bioactive form (P12) were also active in solution. Specifically, P12 bound PDGF-BB (KD=200 nM), enhanced adult human dermal fibroblast (AHDF) survival under serum starvation, oxidative or endoplasmic reticulum stressors, and limited burn-injury progression in a rat hot comb model. Furthermore, P12 inhibited endoplasmic reticulum stress-induced c-Jun N-terminal kinase (JNK) activation. Although many growth factors have been found to bind FN directly or indirectly, here we identify peptide sequences of growth factor-binding sites in FN. The finding of these peptides further delineated how the extracellular matrix protein FN can support cell survival. As the peptide P12 is active in either soluble form or tethered to a substrate, it will have multifactorial uses as a bioactive peptide by itself or in tissue engineering.

Delayed topical p38 MAPK inhibition attenuates full-thickness burn wound inflammatory signaling

Inflammatory signaling pathways, such as p38 mitogen-activated protein kinase (MAPK) play a central role in host responses to injury. In previous studies by the authors, topical p38 MAPK inhibitors effectively attenuated inflammatory signaling in a partial-thickness scald burn model, when applied to the burn wound immediately after injury. However, clinically relevant full-thickness scald burn wounds may act as a barrier to topical immune modulators, and delayed application of topical p38 MAPK inhibitors may not be effective. In this study, the authors evaluate the efficacy of topical p38 MAPK inhibition on full-thickness scald burns with immediate and delayed treatment. C57/BL6 mice received "Sham" or 30% TBSA full-thickness scald burn injury. After injury, the burn wounds were treated with a topical p38 MAPK inhibitor or vehicle. The treatment group received topical p38 MAPK inhibitor either immediately after burn or 4 hours (delayed) after injury. All animals were killed at 12 or 24 hours. Burn wounds underwent histological analyses. Skin and plasma were analyzed by enzyme-linked immunosorbent assay or real-time quantitative polymerase chain reaction for cytokine expression. Full-thickness scald burns resulted from immersion in 62°C water for 25 seconds. Topical p38 MAPK inhibitor attenuated dermal interleukin (IL)-6, MIP-2, and IL-1β expression and plasma IL-6 and MIP-2 cytokine expression. In addition, delayed application of topical p38 MAPK inhibitors significantly reduced dermal and plasma cytokine expression compared with vehicle control. Topical p38 MAPK inhibitors remain potent in reducing full-thickness burn wound inflammatory signaling, even when treatment is delayed by several hours postinjury. Topical application of p38 MAPK inhibitor may be a clinically viable treatment after burn injury.

Stromal vascular fraction improves deep partial thickness burn wound healing

OBJECTIVE

The practice of early burn wound excision and wound closure by immediate autologous skin or skin substitutes is the preferred treatment in extensive deep partial and full-thickness burns. To date there is no proven definite medical treatment to decrease burn wound size and accelerate burn wound healing in modern clinical practice. Stromal vascular fraction is an autologous mixture that has multiple proven beneficial effects on different kinds of wounds. In our study, we investigated the effects of stromal vascular fraction on deep partial-thickness burn wound healing.

METHODS

In this study, 20 Wistar albino rats were used. Inguinal adipose tissue of the rats was surgically removed and stromal vascular fraction was isolated. Thereafter, deep second-degree burns were performed on the back of the rats by hot water. The rats were divided into two groups in a randomized fashion. The therapy group received stromal vascular fraction, whereas the control group received only physiologic serum by intradermal injection. Assessment of the burn wound healing between the groups was carried out by histopathologic and immuno-histochemical data.

RESULTS

Stromal vascular fraction increased vascular endothelial growth factor, proliferating cell nuclear antigen index, and reduced inflammation of the burn wound. Furthermore, vascularization and fibroblastic activity were achieved earlier and observed to be at higher levels in the stromal vascular fraction group.

CONCLUSIONS

Stromal vascular fraction improves burn wound healing by increasing cell proliferation and vascularization, reducing inflammation, and increasing fibroblastic activity.

Burn injury, gender and cancer risk: population-based cohort study using data from Scotland and Western Australia

OBJECTIVE

To investigate the risk of cancer and potential gender effects in persons hospitalised with burn injury.

DESIGN

Population-based retrospective cohort study using record-linkage systems in Scotland and Western Australia.

PARTICIPANTS

Records of 37 890 and 23 450 persons admitted with a burn injury in Scotland and Western Australia, respectively, from 1983 to 2008. Deidentified extraction of all linked hospital morbidity records, mortality and cancer records were provided by the Information Service Division Scotland and the Western Australian Data Linkage Service.

MAIN OUTCOME MEASURES

Total and gender-specific number of observed and expected cases of total ('all sites') and site-specific cancers and standardised incidence ratios (SIRs).

RESULTS

From 1983 to 2008, for female burn survivors, there was a greater number of observed versus expected notifications of total cancer with 1011 (SIR, 95% CI 1.3, 1.2 to 1.4) and 244 (SIR, 95% CI 1.12, 1.05 to 1.30), respectively, for Scotland and Western Australia. No statistically significant difference in total cancer risk was found for males. Significant excesses in observed cancers among burn survivors (combined gender) in Scotland and Western Australian were found for buccal cavity, liver, larynx and respiratory tract and for cancers of the female genital tract.

CONCLUSIONS

Results from the Scotland data confirmed the increased risk of total ('all sites') cancer previously observed among female burn survivors in Western Australia. The gender dimorphism observed in this study may be related to the role of gender in the immune response to burn injury. More research is required to understand the underlying mechanism(s) that may link burn injury with an increased risk of some cancers.

Evaluation of the effects of honey on acute-phase deep burn wounds

This study aimed to clarify the effects of honey on acute-phase deep burn wounds. Two deep burn wounds were created on mice which were divided into four groups: no treatment, silver sulfadiazine, manuka honey, and Japanese acacia honey. Wound sizes were calculated as expanded wound areas and sampled 30 minutes and 1–4 days after wounding for histological observation. The wound sections were subjected to hematoxylin and eosin and immunohistological staining to detect necrotic cells, apoptotic cells, neutrophils, and macrophages. The no treatment group formed a scar. The redness around the wound edges in the silver sulfadiazine group was the most intense. All groups exhibited increased wound areas after wounding. The proportions of necrotic cells and the numbers of neutrophils in the manuka and acacia honey groups were lower than those in the no treatment and silver sulfadiazine groups until day 3; however, there were no significant differences between all groups on day 4. These results show that honey treatment on deep burn wounds cannot prevent wound progression. Moreover, comparing our observations with those of Jackson, there are some differences between humans and animals in this regard, and the zone of hyperemia and its surrounding area fall into necrosis, which contributes to burn wound progression.

Indocyanine green dye angiography accurately predicts survival in the zone of ischemia in a burn comb model

INTRODUCTION

Surgical evaluation of burn depth is performed via clinical observation, with only moderate reliability. While perfusion analysis has been proposed to enhance accuracy, no perfusion study has attempted to predict burn extension into the area of ischemia surrounding the original insult. We examined whether laser Doppler imaging (LDI) and indocyanine green (ICG) angiography predicted survival in the zone of ischemia in a porcine hot comb burn model.

METHODOLOGY

Six full-thickness wounds were created on 5 female Yorkshire swine using a validated porcine hot comb burn model. 4 full-thickness burns were created separated by 3 unburned interspaces that represent the zone of ischemia. The interspaces between each comb burn were monitored using LDI and ICG Angiography at 1, 4, 24, and 48 h after burn. Interspace survival was assessed via gross observation and blinded histological readings 7 days after injury.

RESULTS

ICG Angiographic assessments of burn perfusion were significantly different in viable vs. non-viable interspace perfusion at 1 h, 4 h, and 48 h. Temporal plotting of a trend-line derived from quantitative perfusion measurements rendered two distinct graphs, allowing for the derivation of a predictive algorithm to separate viable and non-viable interspaces. LDI revealed no such prognostic trend.

CONCLUSION

Results from a validated porcine burn comb model suggest that ICG angiography has significant potential in the prediction of burn progression early after burn. However, the full potential of this technology cannot be determined until completion of clinical trials.

Effect of acute thermal injury in status of serum vitamins, inflammatory markers, and oxidative stress markers: preliminary data

The objective of this study was to evaluate the vitamin status, inflammatory markers, and oxidative stress markers in adult patients up to 3 days after thermal injury. This prospective study was conducted with 11 patients 24 to 72 hours after thermal injury (Burn Group), total surface area ranging from 10 to 41%, 34.3 ± 9.3 years, 82% of males, body mass index of 22.3 ± 2.9 kg/m(2). We included 11 healthy adults (Control Group), 36.5 ± 7.6 years, 73% of males, and body mass index of 23.8 ± 2.5 kg/m(2). Laboratory data were measured (plasma total protein, albumin, transferrin, lymphocyte counts, zinc, and iron), as well as serum vitamins (folic acid, vitamin B12, and vitamins A, C, and E), inflammatory stress markers (C-reactive protein, ferritin, and acid α1-glycoprotein) and oxidative stress markers such as glutathione peroxidase (GPx) and thiobarbituric acid reactive substances. The inflammatory stress was characterized by lower levels of total protein (median difference 1.2 g/dL, 95% CI: 0.4-2.1) and albumin (median difference 0.9 g/dL, 95% CI: 0.5-1.5), and higher levels of C-reactive protein (median difference -8.12 mg/dL, 95% CI: -11.62 to 4.61) and α-1 glycoprotein acid (median difference -28.56 mg/dL, 95% CI: -51.57 to -5.07) in burn patients. Decreased serum levels of vitamin A (median difference 1.10 μmol/L, 95% confidence interval [CI]: 0.42-1.66) and vitamin C (median difference 0.82 mg/dL, 95% CI: 0.50-1.04) were also detected. There was no statistical evidence of difference in the serum levels of glutathione peroxidase and thiobarbituric acid reactive substances between burn patients and controls, respectively. Even though there is an inflammatory stress, the obtained data showed that oxidative stress markers are normal 24 to 72 hours after burn injury. The decrease in negative acute phase protein may account for the diminished serum levels of vitamin A, which seems to be related to inflammatory stress. The marked decrease in the serum levels of vitamin C can be justified by augmented cutaneous loss and consumption in the regeneration of vitamin E.

Effects of hyaluronic acid conjugation on anti-TNF-α inhibition of inflammation in burns

Biomaterials capable of neutralizing specific cytokines could form the basis for treating a broad range of conditions characterized by intense, local inflammation. Severe burns, spanning partial- to full-thickness of the dermis, can result in complications due to acute inflammation that contributes to burn progression, and early mediation may be a key factor in rescuing thermally injured tissue from secondary necrosis to improve healing outcomes. In this work, we examined the effects on burn progression and influence on the inflammatory microenvironment of topical application of anti-tumor necrosis factor-α (anti-TNF-α) alone, mixed with hyaluronic acid (HA) or conjugated to HA. We found that non-conjugated anti-TNF-α decreased macrophage infiltration to a greater extent than that conjugated to HA; however, there was little effect on the degree of progression or IL-1β levels. A simple transport model is proposed to analyze the results, which predicts qualitative and quantitative differences between untreated burn sites and those treated with the conjugates. Our results indicate that conjugation of anti-TNF-α to high molecular weight HA provides sustained, local modulation of the post-injury inflammatory responses compared to direct administration of non-conjugated antibodies.

The roles of autophagy and apoptosis in burn wound progression in rats

Understanding the role of cell death in burn wound progression is crucial for giving appropriate diagnoses and designing therapy regimens for burn patients. A well-described and reliable "comb burns model" was employed to evaluate the roles of autophagy and apoptosis in burn wound progression at 2 h, 6 h, 12 h, 24 h, and 48 h post-burn in a rat model. Immunohistochemistry (IHC) results showed that autophagy was detectable in hair follicle epithelium at 2 h post-burn, peaked at 12 h post-burn, then declined. Conversely, apoptosis was mainly located in the stratum epidermis and took place at low levels until 6 h post-burn, at which point it slowly increased. Bcl-2 and Bax, which are regulators of both processes, showed protein expression level patterns that were consistent with the IHC results. This study of autophagy in burn wound tissue progression represents a conceptual expansion of cell death in burn wounds. Based on these results, we suggest that different treatments should be performed on a specific post-burn time course depending on the most prevalent type of cell death occurring at that time.

Endothelial necrosis at 1 hour postburn predicts progression of tissue injury

Burn injury progression has not been well characterized at the cellular level. To define burn injury progression in terms of cell death, histopathologic spatiotemporal relationships of cellular necrosis and apoptosis were investigated in a validated porcine model of vertical burn injury progression. Cell necrosis was identified by high mobility group box 1 protein and apoptosis by Caspase 3a staining of tissue samples taken 1 hour, 24 hours, and 7 days postburn. Level of endothelial cell necrosis at 1 hour was predictive of level of apoptosis at 24 hours (Pearson's r = 0.87) and of level of tissue necrosis at 7 days (Pearson's r = 0.87). Furthermore, endothelial cell necrosis was deeper than interstitial cell necrosis at 1 hour (p < 0.001). Endothelial cell necrosis at 1 hour divided the zone of injury progression (Jackson's zone of stasis) into an upper subzone with necrotic endothelial cells and initially viable adnexal and interstitial cells at 1 hour that progressed to necrosis by 24 hours and a lower zone with initially viable endothelial cells at 1 hour but necrosis and apoptosis of all cell types by 24 hours. Importantly, this spatiotemporal series of events and rapid progression resembles myocardial infarction and stroke and implicates mechanisms of these injuries, ischemia, ischemia reperfusion, and programmed cell death in burn progression.

Moderate systemic hypothermia decreases burn depth progression

BACKGROUND

Therapeutic hypothermia has been proposed to be beneficial in an array of human pathologies including cardiac arrest, stroke, traumatic brain and spinal cord injury, and hemorrhagic shock. Burn depth progression is multifactorial but inflammation plays a large role. Because hypothermia is known to reduce inflammation, we hypothesized that moderate hypothermia will decrease burn depth progression.

METHODS

We used a second-degree 15% total body surface area thermal injury model in rats. Burn depth was assessed by histology of biopsy sections. Moderate hypothermia in the range of 31-33°C was applied for 4h immediately after burn and in a delayed fashion, starting 2h after burn. In order to gain insight into the beneficial effects of hypothermia, we analyzed global gene expression in the burned skin.

RESULTS

Immediate hypothermia decreased burn depth progression at 6h post injury, and this protective effect was sustained for at least 24h. Burn depth was 18% lower in rats subjected to immediate hypothermia compared to control rats at both 6 and 24h post injury. Rats in the delayed hypothermia group did not show any significant decrease in burn depth at 6h, but had 23% lower burn depth than controls at 24h. Increased expression of several skin-protective genes such as CCL4, CCL6 and CXCL13 and decreased expression of tissue remodeling genes such as matrix metalloprotease-9 were discovered in the skin biopsy samples of rats subjected to immediate hypothermia.

CONCLUSIONS

Systemic hypothermia decreases burn depth progression in a rodent model and up-regulation of skin-protective genes and down-regulation of detrimental tissue remodeling genes by hypothermia may contribute to its beneficial effects.

An effective antioxidant drug on prevention of the necrosis of zone of stasis: N-acetylcysteine

The zone of stasis, the encircling area of the zone of coagulation, is a critical area which determines the depth and width of the necrosis in burns. Many agents were proposed to salvage the zone of stasis. Due to the known preventive and therapeutic effects of N-acetylcysteine on hepatotoxicity, nephrotoxicity, pulmonary injury, and multiple organ failure in humans, the effect of N-acetylcysteine on saving the zone of stasis was investigated in this experimental study. The effects of N-acetylcysteine administration via oral or intraperitoneal route was compared in a rat comb-burn model. The extent of burn wounds was evaluated by photography and planimetry in the groups. Additionally, skin samples were obtained to analyze malondialdehyde levels to see the antioxidant effect of N-acetylcysteine. In control group (no treatment), the burn areas went to near total necrosis. In intraperitoneal and oral treatment groups, skin survival occurred in the interspace area of the comb. There was no difference between the groups in terms of MDA concentrations. In conclusion, this study showed us the possible saving effect of N-acetylcysteine on the zone of stasis. N-acetylcysteine may be used in the cases of severe burns, not only for its effects on wound healing but also the systemic effects of the drug.

Reduction of burn progression with topical delivery of (antitumor necrosis factor-α)-hyaluronic acid conjugates

In this study, we explored whether topical application of antibodies targeting tumor necrosis factor-α (TNF-α) or interleukin-6 (IL-6) conjugated to hyaluronic acid (HA) could reduce the extension of necrosis by modulating inflammation locally in a partial-thickness rat burn model. Partial-thickness to deep partial-thickness burn injuries present significant challenges in healing, as these burns often progress following the initial thermal insult, resulting in necrotic expansion and increased likelihood of secondary complications. Necrotic expansion is driven by a microenvironment with elevated levels of pro-inflammatory mediators, and local neutralization of these using antibody conjugates could reduce burn progression. Trichrome-stained tissue sections indicated the least necrotic tissue in (anti-TNF-α)-HA-treated sites, while (anti-IL-6)-HA-treated sites displayed similar outcomes to saline controls. This was confirmed by vimentin immunostaining, which demonstrated that HA treatment alone reduced burn progression by nearly 30%, but (anti-TNF-α)-HA reduced it by approximately 70%. At all time points, (anti-TNF-α)-HA-treated sites showed reduced tissue levels of IL-1β compared to controls, suggesting inhibition of a downstream mediator of inflammation. Decreased macrophage infiltration in (anti-TNF-α)-HA-treated sites compared to controls was elucidated by immunohistochemical staining of macrophages, suggesting a reduction in overall inflammation in all time points. These results suggest that local targeting of TNF-α may be an effective strategy for preventing progression of partial-thickness burns.

Validation of a vertical progression porcine burn model

A major potential goal of burn therapy is to limit progression of partial- to full-thickness burns. To better test therapies, the authors developed and validated a vertical progression porcine burn model in which partial-thickness burns treated with an occlusive dressing convert to full-thickness burns that heal with scarring and wound contraction. Forty contact burns were created on the backs and flanks of two young swine using a 150 g aluminum bar preheated to 70°C, 80°C, or 90°C for 20 or 30 seconds. The necrotic epidermis was removed and the burns were covered with a polyurethane occlusive dressing. Burns were photographed at 1, 24, and 48 hours as well as at 7, 14, 21, and 28 days postinjury. Full-thickness biopsies were obtained at 1, 4, 24, and 48 hours as well as at 7 and 28 days. The primary outcomes were presence of deep contracted scars and wound area 28 days after injury. Secondary outcomes were depth of injury, reepithelialization, and depth of scars. Data were compared across burn conditions using analysis of variance and χ(2) tests. Eight replicate burns were created with the aluminum bar using the following temperature/contact-time combinations: 70/20, 70/30, 80/20, 80/30, and 90/20. The percentage of burns healing with contracted scars were 70/20, 0%; 70/30, 25%; 80/20, 50%; 80/30, 75%; and 90/20, 100% (P = .05). Wound areas at 28 days by injury conditions were 70/20, 8.1 cm(2); 70/30, 7.8 cm(2); 80/20, 6.6 cm(2); 80/30, 4.9 cm(2); and 90/20, 4.8 cm(2) (P = .007). Depth of injury judged by depth of endothelial damage for the 80/20 and 80/30 burns at 1 hour was 36% and 60% of the dermal thickness, respectively. The depth of injury to the endothelial cells 1 hour after injury was inversely correlated with the degree of scar area (Pearson's correlation r = -.71, P < .001). Exposure of porcine skin to an aluminum bar preheated to 80°C for 20 or 30 seconds results initially in a partial-thickness burn that when treated with an occlusive dressing progresses to a full-thickness injury and heals with significant scarring and wound contracture.

Lycopene inhibits caspase-3 activity and reduces oxidative organ damage in a rat model of thermal injury

Oxidative stress has been implicated in various pathological processes including burn induced multiple organ damage. This study investigated the effects of lycopene treatment against oxidative injury in rats with thermal trauma. Under ether anesthesia, shaved dorsum of the rats was exposed to 90°C bath for 10s to induce burn and treated either vehicle (olive oil) or lycopene (50mg/kg orally). Rats were decapitated 48 h after injury and the tissue samples from lung and kidney were taken for histological analysis and the determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO), superoxide dismutase (SOD), catalase (CAT) and caspase-3 activities. Proinflammatory cytokines, TNF-α and IL-1β, were assayed in blood samples. Severe skin scald injury caused a significant decrease in GSH levels, SOD and CAT activities, and significant increases in MDA levels, MPO and caspase-3 activities of tissues. Similarly, plasma TNF-α and IL-1β were elevated in the burn group as compared to the control group. Lycopene treatment reversed all these biochemical indices. According to the findings of the present study, lycopene possesses antiinflammatory, antiapoptotic and antioxidant effects that prevents burn-induced oxidative damage in remote organs.

Controlled mild hypothermia prolongs survival in a rat model of large scald burns

OBJECTIVES

Early surface cooling of burns reduces pain and depth of injury and improves healing. However, there are concerns that cooling of large burns may result in hypothermia and worsen outcomes. In contrast, controlled mild hypothermia improves outcomes after cardiac arrest and traumatic brain injury. The authors hypothesized that controlled mild hypothermia would prolong survival in a rat model of large scald burns.

METHODS

Thirty-six Sprague-Dawley rats (250-300 g) were anesthetized with 40 mg/kg intramuscular ketamine and 5 mg/kg xylazine, with supplemental inhalational isoflurane as needed. A single full-thickness scald burn covering 40% of total body surface area was created on each of the rats using a Mason-Walker template placed in boiling water (100 °C) for a period of 10 seconds. The rats were then randomized to hypothermia (n = 18) or no hypothermia (n = 18). Core body temperature was continuously monitored with a rectal temperature probe. In the experimental group, mild hypothermia was induced by applying ice packs over the prone rats until their rectal temperature was reduced by 2 °C for a period of 2 hours. After 2 hours of hypothermia, the rats were rewarmed back to their baseline temperature with a heating pad. The control rats were not cooled. The rats were monitored until death or for a period of 7 days, whichever was greater. The primary outcome was time to death. The difference in survival between the groups was determined using Kaplan-Meier analysis and the log-rank test.

RESULTS

  Hypothermia was induced in all experimental rats within a mean of 22 minutes (95% confidence interval [CI] = 17 to 27). The numbers of nonhypothermic and hypothermic rats that were dead at each time point were as follows: 2 hours, five versus none; 18 hours, 16 versus five; 24 hours, 18 versus eight; and 48 hours, 18 versus 13 (p = 0.05). There were no additional deaths after 48 hours. The mean time to survival of the hypothermic rats was significantly greater than that of the nonhypothermic rats (p < 0.001).

CONCLUSIONS

Induction of brief, mild hypothermia prolongs survival and increases the survival rate in nonresuscitated rats with large scald burns.