Excision and skin grafting of thermal burns

Early Enzymatic Burn Debridement: Results of the DETECT Multicenter Randomized Controlled Trial

Since 1970 surgeons have managed deep burns by surgical debridement and autografting. We tested the hypothesis that enzymatic debridement with NexoBrid would remove the eschar reducing surgery and achieve comparable long-term outcomes as standard of care (SOC). In this Phase 3 trial, we randomly assigned adults with deep burns (covering 3-30% of total body surface area [TBSA]) to NexoBrid, surgical or nonsurgical SOC, or placebo Gel Vehicle (GV) in a 3:3:1 ratio. The primary endpoint was complete eschar removal (ER) at the end of the debridement phase. Secondary outcomes were need for surgery, time to complete ER, and blood loss. Safety endpoints included wound closure and 12 and 24-months cosmesis on the Modified Vancouver Scar Scale. Patients were randomized to NexoBrid (n = 75), SOC (n = 75), and GV (n = 25). Complete ER was higher in the NexoBrid versus the GV group (93% vs 4%; P < .001). Surgical excision was lower in the NexoBrid vs the SOC group (4% vs 72%; P < .001). Median time to ER was 1.0 and 3.8 days for the NexoBrid and SOC respectively (P < .001). ER blood loss was lower in the NexoBrid than the SOC group (14 ± 512 mL vs 814 ± 1020 mL, respectively; P < .0001). MVSS scores at 12 and 24 months were noninferior in the NexoBrid versus SOC groups (3.7 ± 2.1 vs 5.0 ± 3.1 for the 12 months and 3.04 ± 2.2 vs 3.30 ± 2.76 for the 24 months). NexoBrid resulted in early complete ER in >90% of burn patients, reduced surgery and blood loss. NexoBrid was safe and well tolerated without deleterious effects on wound closure and scarring.

Autologous Skin Cell Suspension for Full-Thickness Skin Defect Reconstruction: Current Evidence and Health Economic Expectations

Despite differing etiologies, acute thermal burn injuries and full-thickness (FT) skin defects are associated with similar therapeutic challenges. When not amenable to primary or secondary closure, the conventional standard of care (SoC) treatment for these wound types is split-thickness skin grafting (STSG). This invasive procedure requires adequate availability of donor skin and is associated with donor site morbidity, high healthcare resource use (HCRU), and costs related to prolonged hospitalization. As such, treatment options that can facilitate effective healing and donor skin sparing have been highly anticipated. The RECELL® Autologous Cell Harvesting Device facilitates preparation of an autologous skin cell suspension (ASCS) for the treatment of acute thermal burns and FT skin defects. In initial clinical trials, the approach showed superior donor skin-sparing benefits and comparable wound healing to SoC STSG among patients with acute thermal burn injuries. These findings led to approval of RECELL for this indication by the US Food and Drug Administration (FDA) in 2018. Subsequent clinical evaluation in non-thermal FT skin wounds showed that RECELL, when used in combination with widely meshed STSG, provides donor skin-sparing advantages and comparable healing outcomes compared with SoC STSG. As a result, the device received FDA approval in June of 2023 for treatment of FT skin defects caused by traumatic avulsion or surgical excision or resection. Given that health economic advantages have been demonstrated for RECELL ± STSG versus STSG alone when used for burn therapy, it is prudent to examine similarities in the burn and FT skin defect treatment pathways to forecast the potential health economic advantages for RECELL when used in FT skin defects. This article discusses the parallels between the two indications, the clinical outcomes reported for RECELL, and the HCRU and cost benefits that may be anticipated with use of the device for non-thermal FT skin defects.

Novel approach for enhancing skin allograft survival by bioadhesive nanoparticles loaded with rapamycin

Skin graft rejection is a significant challenge in skin allografts for skin defects, particularly in extensive burn injury patients when autografts are insufficient. Enhancing the survival duration of allogeneic skin grafts can improve the success rate of subsequent autologous skin grafting, thereby promoting the therapeutic efficacy for wound healing. Rapamycin (Rapa), a potent immunosuppressant with favorable efficacy in organ transplantation, is limited by its systemic administration-associated toxicity and side effects. Therefore, addressing the short survival time of allogeneic skin grafts and minimizing the toxicity related to systemic application of immunosuppressive agents is an urgent requirement. Here, we present a topical formulation based on bioadhesive poly (lactic acid)-hyperbranched polyglycerol nanoparticles (BNPs) with surface-modified encapsulation of Rapamycin (Rapa/BNPs), applied for local immunosuppression in a murine model of allogeneic skin grafts. Our Rapa/BNPs significantly prolong nanoparticle retention, reduce infiltration of T lymphocytes and macrophages, decrease the level of pro-inflammatory cytokines and ultimately extend skin allograft survival with little systemic toxicity compared to free Rapa or Rapamycin-loaded non-bioadhesive nanoparticles (Rapa/NNPs) administration. In conclusion, Rapa/BNPs effectively deliver local immunosuppression and demonstrate potential for enhancing skin allograft survival while minimizing localized inflammation, thus potentially increasing patient survival rates for various types of skin defects.

Advances in laser speckle imaging: From qualitative to quantitative hemodynamic assessment

Laser speckle imaging (LSI) techniques have emerged as a promising method for visualizing functional blood vessels and tissue perfusion by analyzing the speckle patterns generated by coherent light interacting with living biological tissue. These patterns carry important biophysical tissue information including blood flow dynamics. The noninvasive, label-free, and wide-field attributes along with relatively simple instrumental schematics make it an appealing imaging modality in preclinical and clinical applications. The review outlines the fundamentals of speckle physics and the three categories of LSI techniques based on their degree of quantification: qualitative, semi-quantitative and quantitative. Qualitative LSI produces microvascular maps by capturing speckle contrast variations between blood vessels containing moving red blood cells and the surrounding static tissue. Semi-quantitative techniques provide a more accurate analysis of blood flow dynamics by accounting for the effect of static scattering on spatiotemporal parameters. Quantitative LSI such as optical speckle image velocimetry provides quantitative flow velocity measurements, which is inspired by the particle image velocimetry in fluid mechanics. Additionally, discussions regarding the prospects of future innovations in LSI techniques for optimizing the vascular flow quantification with associated clinical outlook are presented.

Human amniotic membranes as an allogenic biological dressing for the treatment of burn wounds: Protocol for a randomized-controlled study

Background

Burn wounds pose significant challenges in medical treatment due to their devastating nature and resource-intensive requirements. Temporary coverage of burn wounds using synthetic or biological dressings allows for reepithelization before definitive skin grafting. Allogenic skin grafts have been widely used but come with drawbacks such as rejection and disease transmission. The use of amniotic membranes (AMs) offers a promising alternative for temporary coverage, as they possess biological properties that promote faster healing and improved scar quality. The various components of the amniotic membrane, including pluripotent stem cells, extracellular matrix proteins, and regenerative factors, contribute to cell growth, migration, and differentiation, as well as preservation of the original epithelial phenotype.

Objective

Reliable information on the treatment of burn wounds with AM is needed. The knowledge gained in this project may help to include this advantageous modern concept of biological dressings in clinical practice. The purpose of this study is to use human amniotic membranes from our in hospital laboratory, as an allogenic biological dressing after enzymatic debridement in superficial partial thickness, deep partial thickness or full thickness burn wounds.

Methods

We will include 30 patients in a randomized-controlled trial with each patient receiving the study intervention and the control intervention. Two 7 × 7 cm burn wound areas will be compared regarding percentage of skin graft take, healing time, healing percentage value and total healing time. Human amniotic membranes will be compared to allogenic skin grafts.

Mimicking fat grafting of fibrotic scars using 3D-organotypic skin cultures

Wound healing of deep burn injuries is often accompanied by severe scarring, such as hypertrophic scar (HTS) formation. In severe burn wounds, where the subcutis is also damaged, the scars adhere to structures underneath, resulting in stiffness of the scar and impaired motion. Over the recent years, a promising solution has emerged: autologous fat grafting, also known as lipofilling. Previous clinical reports have shown that the anti-fibrotic effect has been attributed to the presence of adipose-derived stromal cells (ADSC). In the proposed study, we aim to investigate the effect of fat grafting in 3D organotypic skin cultures mimicking an HTS-like environment. To this end, organotypic skin cultures were embedded with normal skin fibroblasts (NF) or HTS-derived fibroblasts with or without incorporation of human adipose subcutaneous tissue (ADT) and one part was thermally wounded to examine their effect on epithelialization. The developed skin cultures were analysed on morphology and protein level. Analysis revealed that ADT-containing organotypic skin cultures comprise an improved epidermal homeostasis, and a fully formed basement membrane, similar to native human skin (NHS). Furthermore, the addition of ADT significantly reduced myofibroblast presence, which indicates its anti-fibrotic effect. Finally, re-epithelialization measurements showed that ADT reduced re-epithelialization in skin cultures embedded with NFs, whereas HTS-fibroblast-embedded skin cultures showed complete wound closure. In conclusion, we succeeded in developing a 3D organotypic HTS-skin model incorporated with subcutaneous tissue that allows further investigation on the molecular mechanism of fat grafting.

Anacaulase-bcdb for the treatment of severe thermal burns

INTRODUCTION

Accurate burn depth assessment and early excision of burn eschar with maximal dermal preservation are key concepts in the optimal care of burn injury. Although excision with knife has long since been standard of care, a newer technique for wound bed preparation utilizing a bromelain-based enzyme has gained popularity worldwide and may offer several advantages.

AREAS COVERED

Here we report the pharmacologic properties, evidence for clinical efficacy, safety, and tolerability of anacaulase-bcdb for the treatment of deep partial thickness and full thickness burns.

EXPERT OPINION

Anacaulase-bcdb is a safe, non-surgical, selective eschar removal agent. It offers advantages over surgical excision of burn with knife and fulfills two unmet needs: burn depth assessment and dermal preservation during excision. Evidence supports a faster time to complete eschar removal; reduced number of operations; reduction in the amount of autografting, length of stay, and blood loss; prevention of burn induced compartment syndrome; and improved cosmetic outcome.

Full Skin Equivalent Models for Simulation of Burn Wound Healing, Exploring Skin Regeneration and Cytokine Response

Healing of burn injury is a complex process that often leads to the development of functional and aesthetic complications. To study skin regeneration in more detail, organotypic skin models, such as full skin equivalents (FSEs) generated from dermal matrices, can be used. Here, FSEs were generated using de-epidermalized dermis (DED) and collagen matrices MatriDerm^® and Mucomaix^®. Our aim was to validate the MatriDerm- and Mucomaix-based FSEs for the use as in vitro models of wound healing. Therefore, we first characterized the FSEs in terms of skin development and cell proliferation. Proper dermal and epidermal morphogenesis was established in all FSEs and was comparable to ex vivo human skin models. Extension of culture time improved the organization of the epidermal layers and the basement membrane in MatriDerm-based FSE but resulted in rapid degradation of the Mucomaix-based FSE. After applying a standardized burn injury to the models, re-epithelization occurred in the DED- and MatriDerm-based FSEs at 2 weeks after injury, similar to ex vivo human skin. High levels of pro-inflammatory cytokines were present in the culture media of all models, but no significant differences were observed between models. We anticipate that these animal-free in vitro models can facilitate research on skin regeneration and can be used to test therapeutic interventions in a preclinical setting to improve wound healing.

Burn-injured skin is marked by a prolonged local acute inflammatory response of innate immune cells and pro-inflammatory cytokines

The systemic and local immune response in burn patients is often extreme and derailed. As excessive inflammation can damage healthy tissues and slow down the healing process, modulation of inflammatory responses could limit complications and improve recovery. Due to its complexity, more detailed information on the immune effects of thermal injury is needed to improve patient outcomes. We therefore characterized and quantified subsets of immune cells and mediators present in human burn wound tissue (eschar), sampled at various time points. This study shows that after burn injury, the number of immune cells were persistently increased, unlike the normal wound healing process. There was an immediate, strong increase in neutrophils and a moderate increase in monocytes/macrophages and lymphocytes, especially in the second and third week post burn. The percentage of classical (CD14highCD16-) monocytes/macrophages demonstrated a steady decrease over time, whereas the proportion of intermediate (CD14highCD16+) monocytes/macrophages slowly increased. The absolute numbers of T cells, NK cells and B cells increased up to week 3, while the fraction of γδ T cells was increased only in week 1. Secretome profiling revealed high levels of chemokines and an overall pro-inflammatory cytokine milieu in burn tissue. The local burn immune response shows similarities to the systemic immune reaction, but differs in neutrophil maturity and lymphocyte composition. Altogether, the neutrophil surges, high levels of pro-inflammatory cytokines and limited immunosuppression might be key factors that prolong the inflammation phase and delay the wound healing process in burns.

No statistically significant difference in long term scarring outcomes of pediatric burns patients treated surgically vs. those treated conservatively

Introduction

Paediatric burns are a common clinical presentation. The long-term scar outcomes in paediatric burns patients are relatively unknown as most are discharged after 6 weeks follow up, apart from the small number that are followed up by scar services depending on geographical availability. We aimed to determine whether the long-term scarring outcomes are significantly different in those who had surgical treatment with Versajet® debridement and Biobrane®, vs. those treated conservatively with non-adherent Mepitel® and Acticoat® dressings, in a cohort of paediatric burns patients.

Methods

The parents of all paediatric burns patients admitted to Stoke Mandeville Hospital from October 2014 to September 2017 were contacted by telephone to fill in the paediatric Brisbane Burn Scar Impact Profile (BBSIP), the only patient reported outcome measure (PROM) specifically aimed at children. The results from the questionnaires underwent statistical analysis to see if there was a significant difference in questionnaire scores between children treated surgically vs. those treated conservatively.

Results

A total of 107 children were admitted in the timeframe, responses were received from 34 patients with 13 having been treated surgically and 21 having been treated conservatively. In all 58 questions that make up the BBSIP, there was no statistically significant difference observed in the scores of those treated surgically vs. those treated conservatively. For 31 questions on the BBSIP, the lowest score indicating the best outcome was observed in all patients in both groups.

Discussion

Surgical management for burns is always the last resort. Our results could be interpreted to suggest clinicians need not fear the longer-term impact a scar may have when deciding whether to treat a paediatric burns patient surgically or conservatively. This study is the first to assess longer-term scar outcomes using the BBSIP. A larger data set and comparison with other burn units in the UK may help to provide more information on scar outcomes between different methods of surgical and conservative treatment. We found no statistically significant difference in the long-term scar outcomes as assessed by the BBSIP in paediatric burn patients treated with Versajet® debridement and Biobrane®, vs. those treated conservatively with non-adherent Mepitel® and Acticoat® dressings.

Preliminary Single-Center Experience of Bromelain-Based Eschar Removal in Children with Mixed Deep Dermal and Full Thickness Burns

Introduction: Early eschar removal is the standard management of burns. The goal is to remove all of the necrotic tissue and render the wound suitable for healing or skin grafting. The enzymatic debridement of burn wounds allows for minimally invasive removal of burn eschar. The aim of the study was to describe and compare the demographic characteristics, surgical treatment and outcomes of patients treated with Nexobrid® with patients who had standard surgical excision. Material and Methods: A retrospective review was conducted on children who underwent enzymatic debridement. The study group was compared with children treated with the standard of care (SoC). Results: Twelve children (mean age 8 years, range 3 to 15 years) with mixed deep dermal and full thickness burn wounds were treated with Nexobrid®. The mean size of the burns was 29% TBSA. The median percentage TBSA debrided using Nexobrid® was 15% (range 2–27%). In a clinical assessment, enzymatic debridement was effective in removing dead tissue in a single application. No adverse reaction to Nexobrid® and serious complications after enzymatic procedure were recorded in the study group. The estimated relative risk of the need for reconstructive procedures decreases 3.5 times for the study group (RR 3.5, 95%CI 0.9–13.5, p = 0.089). Conclusion: The bromelain-based enzymatic method offers a good and safe debridement option to improve the treatment and life quality of children with severe burns. The main outcome of interest was the number of reconstructive procedures due to scar contractures, which was reduced in the group treated enzymatically compared to the SoC-treated children.

Israeli Innovations in the Field of Plastic Surgery

Numerous innovations within the field of plastic surgery have been developed in Israel over the last few decades. Many of these therapeutic devices and techniques have been established globally with demonstrable efficacy and respectable safety profiles. This article offers an overview of recent Israeli cutting-edge medical therapeutic solutions contributing to the global practice of plastic surgery.

Hydrosurgical and conventional debridement of burns: randomized clinical trial

BACKGROUND

Tangential excision of burned tissue followed by skin grafting is the cornerstone of burn surgery. Hydrosurgery has become popular for tangential excision, with the hypothesis that enhanced preservation of vital dermal tissue reduces scarring. The aim of this trial was to compare scar quality after hydrosurgical versus conventional debridement before split-skin grafting.

METHODS

A double-blind randomized within-patient multicentre controlled trial was conducted in patients with burns that required split-skin grafting. One wound area was randomized to hydrosurgical debridement and the other to Weck knife debridement. The primary outcome was scar quality at 12 months, assessed with the observer part of the Patient and Observer Scar Assessment Scale (POSAS). Secondary outcomes included complications, scar quality, colour, pliability, and histological dermal preservation.

RESULTS

Some 137 patients were randomized. At 12 months, scars of the hydrosurgical debrided wounds had a lower POSAS observer total item score (mean 2.42 (95 per cent c.i. 2.26 to 2.59) versus 2.54 (95 per cent c.i. 2.36 to 2.72; P = 0.023)) and overall opinion score (mean 3.08 (95 per cent c.i. 2.88 to 3.28) versus 3.30 (95 per cent c.i. 3.09-3.51); P = 0.006). Patient-reported scar quality and pliability measurements were significantly better for the hydrosurgically debrided wounds. Complication rates did not differ between both treatments. Histologically, significantly more dermis was preserved with hydrosurgery (P < 0.001).

CONCLUSION

One year after surgery scar quality and pliability was better for hydrosurgically debrided burns, probably owing to enhanced histological preservation of dermis.

REGISTRATION NUMBER

Trial NL6085 (NTR6232 (http://www.trialregister.nl)).

Assessment and Management of Pain in Patients Sustaining Burns at Emergency Department Kenyatta National Hospital, Kenya: A Descriptive Study

Background: Poorly managed burn pain affects the victim by delayed healing, psychological disturbances, and chronic pain. Burn injuries are the fourth leading cause of injuries worldwide. The incidence of thermal burns in Kenya is 3%. Pain assessment and control are integral parts of management that a burn victim should be offered. We lack data on pain management in burn patients during setup. Methods: A descriptive study was carried out at the emergency department (ED) of Kenyatta National Hospital. We enrolled patients who sustained thermal burns until a sample 138 patients was reached. Enrollment of patients was done from February to August 2015. The pain level was assessed using a visual analogue scale, and the Lund and Browder chart was used to record the depth and extent of the burn. Data on the type of analgesia prescribed and its route of administration was collected. Data was analyzed using STATA v.11. Results: The median age of the sample was 28 years with a male to female ratio 1.8:1. The majority of the victims (38%) sustained flame burns. The median total body surface area was 19.5%. Pain assessment was done in 2% with a visual analogue scale and face pain recognition scale. Mean Visual Analogue score was 7. Analgesia was offered to 96% of participants, and it was unimodal in the majority, 76.7%, and the preferred drug of choice was morphine. The majority of all burn patients had sustained moderate to major burns. The tools used to assess pain in this hospital were Face Pain Recognition Scale and Visual Analogue Scale; however, pain assessment was done on a meagre 2% of the sample. Conclusions: A minority of the patients had any sort of pain assessment done at the emergency department. As a result, burn pain was inappropriately managed. There is a need to improve the assessment of burn pain and improve its management by encouraging training of ED burn care providers by burn surgeons and pain therapists.

Does Probiotic Consumption Enhance Wound Healing? A Systematic Review

The use of probiotics is one of the emerging lines of treatment for wound healing. This systematic review aimed to summarize currently available evidence on the effect of oral or enteral probiotic therapy on skin or oral mucosal wound healing in humans. To verify the developments in this field and the level of available scientific evidence, we applied a broad search strategy with no restrictions on wound type, target population, probiotic strain, or intervention protocol used. This review included seven studies involving 348 individuals. Four studies reported positive outcomes for healing improvement after probiotic therapy, and none of the studies reported adverse effects or a marked increase in wound healing time. The positive or neutral results observed do not generate strong evidence regarding the effectiveness of probiotics for wound healing. However, they suggest a promising field for future clinical research where the probiotic strains used, type of wounds, and target population are controlled for.

Evaluation of burned hand function after enzymatic debridement

Hand burns are common injuries that can result in long-term impairment of hand function. Enzymatic debridement (ED) prevents damage to the viable dermis due to the procedure's selectivity and has become an option for obtaining an accurate depth assessment and enabling wound re-epithelialization with less skin graft use. We conducted a prospective study from July 2015 to July 2018, which enrolled patients with deep partial-thickness hand burns and treated them with ED using bromelain. After a specified period, we assessed the patients' hand function, using the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and the Michigan Hand Outcomes Questionnaire (MHOQ) to assess their disabilities and activities of daily life, respectively. We assessed the hand joint range of motion using a goniometer and assessed scar quality with the Vancouver Scar Scale (VSS). We analyzed 72 patients with 90 burned hands at 3 months and, at the final assessment, 69 patients with 86 burned hands. Fire was the most common cause of the burns. Bromelain allowed for early debridement (73.6% during the first 24 h). At the 3-month evaluation, the mean DASH and MHOQ scores were 2.35 and 97.9%, respectively, with a high inverse correlation between the 2 types of scores (Spearman's rho, -0.78; p < .001). The mean wrist flexion and extension were 85.7 and 80°, respectively, the mean metacarpophalangeal flexion was 88.3°, the proximal interphalangeal (PIP) flexion was 112.9°, and the thumb opposition was 77°. The mean VSS score was 2.87. At the final evaluation, with a minimum follow-up of 391 days, the mean DASH and MHOQ scores were 0.18 and 99.71%, respectively. ED with bromelain in deep partial-thickness hand burns resulted in normal values at 3 months and at over 1 year of follow-up, with complete restoration of function and quality of life and good scar results.

Clostridium Collagenase Impact on Zone of Stasis Stabilization and Transition to Healthy Tissue in Burns

Clostridium collagenase has provided superior clinical results in achieving digestion of immediate and accumulating devitalized collagen tissue. Recent studies suggest that debridement via Clostridium collagenase modulates a cellular response to foster an anti-inflammatory microenvironment milieu, allowing for a more coordinated healing response. In an effort to better understand its role in burn wounds, we evaluated Clostridium collagenase’s ability to effectively minimize burn progression using the classic burn comb model in pigs. Following burn injury, wounds were treated with Clostridium collagenase or control vehicle daily and biopsied at various time points. Biopsies were evaluated for factors associated with progressing necrosis as well as inflammatory response associated with treatment. Data presented herein showed that Clostridium collagenase treatment prevented destruction of dermal collagen. Additionally, treatment with collagenase reduced necrosis (HMGB1) and apoptosis (CC3a) early in burn injuries, allowing for increased infiltration of cells and protecting tissue from conversion. Furthermore, early epidermal separation and epidermal loss with a clearly defined basement membrane was observed in the treated wounds. We also show that collagenase treatment provided an early and improved inflammatory response followed by faster resolution in neutrophils. In assessing the inflammatory response, collagenase-treated wounds exhibited significantly greater neutrophil influx at day 1, with macrophage recruitment throughout days 2 and 4. In further evaluation, macrophage polarization to MHC II and vascular network maintenance were significantly increased in collagenase-treated wounds, indicative of a pro-resolving macrophage environment. Taken together, these data validate the impact of clostridial collagenases in the pathophysiology of burn wounds and that they complement patient outcomes in the clinical scenario.

Therapeutic effect of mesenchymal stem cells on histopathological, immunohistochemical, and molecular analysis in second-grade burn model

Background and aim

Deleterious cutaneous tissue damages could result from exposure to thermal trauma, which could be ameliorated structurally and functionally through therapy via the most multipotent progenitor bone marrow mesenchymal stem cells (BM-MSCs). This study aimed to induce burns and examine the effect of BM-MSCs during a short and long period of therapy.

Material and methods

Ninety albino rats were divided into three groups: group I (control); group II (burn model), the animals were exposed to the preheated aluminum bar at 100°C for 15 s; and group III (the burned animals subcutaneously injected with BM-MSCs (2×10⁶ cells/ ml)); they were clinically observed and sacrificed at different short and long time intervals, and skin samples were collected for histopathological and immunohistochemical examination and analysis of different wound healing mediators via quantitative polymerase chain reaction (qPCR).

Results

Subcutaneous injection of BM-MSCs resulted in the decrease of the wound contraction rate; the wound having a pinpoint appearance and regular arrangement of the epidermal layer with thin stratum corneum; decrease in the area percentages of ADAMs10 expression; significant downregulation of transforming growth factor-β (TGF-β), interleukin-6 (IL-6), tumor necrotic factor-α (TNF-α), metalloproteinase-9 (MMP-9), and microRNA-21; and marked upregulation of heat shock protein-90α (HSP-90α) especially in late stages.

Conclusion

BM-MSCs exhibited a powerful healing property through regulating the mediators of wound healing and restoring the normal skin structures, reducing the scar formation and the wound size.

Contemporary Aspects of Burn Care

The past one hundred years have seen tremendous improvements in burn care, allowing for decreased morbidity and mortality of this pathology. The more prominent advancements occurred in the period spanning 1930-1980; notably burn resuscitation, early tangential excision, and use of topical antibiotic dressings; and are well documented in burn literature. This article explores the advancements of the past 40 years and the areas of burn management that are presently topics of active discussion and research.

Recommendations for burns care in mass casualty incidents: WHO Emergency Medical Teams Technical Working Group on Burns (WHO TWGB) 2017-2020

Health and logistical needs in emergencies have been well recognised. The last 7 years has witnessed improved professionalisation and standardisation of care for disaster affected communities - led in part by the World Health Organisation Emergency Medical Team (EMT) initiative. Mass casualty incidents (MCIs) resulting in burn injuries present unique challenges. Burn management benefits from specialist skills, expert knowledge, and timely availability of specialist resources. With burn MCIs occurring globally, and wide variance in existing burn care capacity, the need to strengthen burn care capability is evident. Although some high-income countries have well-established disaster management plans, including burn specific plans, many do not - the majority of countries where burn mass casualty events occur are without such established plans. Developing globally relevant recommendations is a first step in addressing this deficit and increasing preparedness to deal with such disasters. Global burn experts were invited to a succession of Technical Working Group on burns (TWGB) meetings to: 1) review literature on burn care in MCIs; and 2) define and agree on recommendations for burn care in MCIs. The resulting 22 recommendations provide a framework to guide national and international specialist burn teams and health facilities to support delivery of safe care and improved outcomes to burn patients in MCIs.

Therapeutic Targeting of Neutrophil Extracellular Traps Improves Primary and Secondary Intention Wound Healing in Mice

Background

Neutrophils are the first responders in wound healing after injury that mediate pro- and anti-inflammatory activities i.a. through the formation of extracellular traps (NETs). However, excessive NETs presence in wound tissue can cause local hyperinflammation and -coagulation resulting in delayed wound healing. To improve wound healing, we aimed to examine the role of NETs and DNase1 on primary and secondary wound healing.

Methods

The study included 93 C57BL/6 mice, with 3 different genotypes: wildtype, Pad4-, and DNase1-Knockout (KO). Pad4-KO mice show limited NETs formation, while DNase1-KO mice cannot disintegrate them. All 3 genotypes were included in (1) a laparotomy group and (2) a thermal injury group. Animals in both groups either received DNase1 or a vehicle i.p. post wound induction and wound assessment and euthanasia were conducted. Laparotomy and burn scars were assessed using the stony brook scar evaluation scale and modified Yeong scale respectively. Tissue was analyzed histologically using H&E staining. Ly6g, Collagen I and III, SMA, and Fibrinogen were visualized and neutrophils activation (NE, MPO) and NETs (H3cit) formation assessed.

Results

All animals survived with no complications. DNase1 treatment led to a significantly improved scar appearance in both groups, which was also seen in Pad4-KO mice. In the laparotomy group DNase1 improved collagen deposition and fibrin concentration was significantly reduced by DNase1 treatment. Markers of neutrophil activation were significantly reduced in the treatment and Pad4-KO group. In the thermal injury group wound closure time was significantly reduced after DNase1 treatment and in the Pad4-KO group. Even though inflammation remained high in the thermal injury model over time, neutrophil activation and NETs formation were significantly reduced by DNase1 treatment compared to controls.

Discussion

Primary and secondary intention wound healing is improved by targeting NETs through DNase1 treatment or genetic KO, as assessed by wound closure time and scar appearances. Additionally, wound stability was not affected by DNASE treatment. The results suggest that overall wound healing is accelerated and DNase1 appears to be a promising option to reduce scar formation; which should be evaluated in humans.

Imaging human skin autograft integration with optical coherence tomography

Background

Skin autografting is a common clinical procedure for reconstructive surgery. Despite its widespread use, very few studies have been conducted to non-invasively evaluate and monitor the vascular and structural features of skin grafts. This study, therefore, aims to demonstrate the potential of optical coherence tomography (OCT) alongside OCT-based angiography (OCTA) to non-invasively image and monitor human skin graft health and integration over time.

Methods

An in-house-built clinical prototype OCT system was used to acquire OCT/OCTA images from patients who underwent split-thickness skin graft surgery following severe burn damage to the skin. The OCT imaging was carried out at multiple locations over multiple time points with a field of view of ~9 mm × 9 mm and a penetration depth of ~1.5 mm. In addition to obtaining high-resolution qualitative images, we also quantitatively measured and compared specific structural and vascular parameters, such as identifiable layer thickness and corresponding vascular area density and diameter.

Results

Two patients (patient #1 and #2) were enrolled for this preliminary study. Vascular and structural features were successfully imaged and measured in the graft tissue and integration layer immediately beneath at different time points. Revascularization, healing, and integration were monitored with patient-specific details. Results of the quantitative image analysis from patient #1 indicated that integration layer thickness 16-day post-surgery was significantly less (~50%) than that of 7-day post-surgery. Additionally, with patient #2, significant growth (~20%) was seen with the vascular area density of both the graft and corresponding integration layer beneath between 6 and 14 days post-surgery.

Conclusions

Our preliminary studies show that OCT/OCTA has clinical potential to image and measure numerous features of human skin graft health and integration in the days and weeks following split-thickness surgery. For the first time, we demonstrate the applicability of non-invasive imaging technology for novel clinical uses that could eventually aid in the betterment of surgical practices and clinical outcomes.

Locally activated mitophagy contributes to a "built-in" protection against early burn-wound progression in rats

AIMS

Deep burn-wounds undergo a dynamic progression in the initial or periburn area after insults, and the zone of stasis is the crucial region suffering the deterioration, considered as salvageable. Few studies explored the role of mitochondria in this process. This study is to clarify a possible "built-in" protection of mitophagy.

MAIN METHODS

A classic "comb" scald rat model was established. Histological and blood-flow observation were processed based on hematoxylin-eosin staining and laser analysis. Oxidative and apoptotic status were analyzed by commercial kits. Transmission-electron microscope, immunofluorescence staining, and western blot were applied to detect the mitophagy in the zone of stasis and potential regulators. Adenovirus-based gene-silence contributed to determine the role of HIF-1α as a regulatory mediator.

KEY FINDINGS

We found that burn-caused typical ischemia and histological deterioration in the zone of stasis, in parallel with increases in oxidative stress and apoptosis. Mitochondrial damage was involved in the aforementioned changes. Furthermore, we detected mitophagy in burn-wounds, which was contradictory to the burn-wound conversion. HIF-1α expression was closely related to the level of mitophagy, while BNIP3 and PARKIN are involved downstream.

SIGNIFICANCE

We demonstrate that burn-induced mitochondrial impairment contributes to the mobilization of injurious mechanisms in the zone of stasis and that mitophagy provides a beneficial way to protect against burn-wound progression via the elimination of damaged mitochondria. Our findings offer insights into mitochondrial quality control in burn-wound progression and suggest the novel concept that HIF-1α may be a therapeutic target due to its possible regulation on BNIP3- or PARKIN-mediated mitophagy.

Total full-thickness skin grafting for treating patients with extensive facial burn injury: A 10-year experience

INTRODUCTION

Facial burns are not only a severe burn injury, but result in psychological disturbance. The improvement of the methods of treating facial burns remains topical. The aim of the study was to evaluate the effectiveness of approach based on full-thickness skin autografting for facial burn injuries.

METHODS

During 2000-2019, ninety seven patients with the facial burn were treated in Burn Center. All patient were divided into two groups. The comparative analysis between groups was done.

RESULTS

Group A was treated with full-thickness skin grafts (42 patients - 43.3%). Since 2010, total full-thickness skin graft was used in 11 patients from Group A. In group B, 55 patients (56.7%) were treated with split-thickness skin grafts, including 9 patients (16.4%) with total split-thickness skin graft transplantation. Total full-thickness skin graft was performed in case of a deep and extensive facial burn and cicatricial deformities. During the long-term period, a positive cosmetic result and the absence of indications for reconstructive operations were noted.

CONCLUSION

The approach of facial burn treatment based on total full-thickness skin graft allows conditions for engraftment and adaptation of autograft, reduces the risk of scar developing and achieves maximum cosmetic results of treatment.

Hydrosurgical debridement versus conventional surgical debridement for acute partial-thickness burns

BACKGROUND

Burn injuries are the fourth most common traumatic injury, causing an estimated 180,000 deaths annually worldwide. Superficial burns can be managed with dressings alone, but deeper burns or those that fail to heal promptly are usually treated surgically. Acute burns surgery aims to debride burnt skin until healthy tissue is reached, at which point skin grafts or temporising dressings are applied. Conventional debridement is performed with an angled blade, tangentially shaving burned tissue until healthy tissue is encountered. Hydrosurgery, an alternative to conventional blade debridement, simultaneously debrides, irrigates, and removes tissue with the aim of minimising damage to uninjured tissue. Despite the increasing use of hydrosurgery, its efficacy and the risk of adverse events following surgery for burns is unclear.

OBJECTIVES

To assess the effects of hydrosurgical debridement and skin grafting versus conventional surgical debridement and skin grafting for the treatment of acute partial-thickness burns.

SEARCH METHODS

In December 2019 we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE (including In-Process & Other Non-Indexed Citations); Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that enrolled people of any age with acute partial-thickness burn injury and assessed the use of hydrosurgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data extraction, 'Risk of bias' assessment, and GRADE assessment of the certainty of the evidence.

MAIN RESULTS

One RCT met the inclusion criteria of this review. The study sample size was 61 paediatric participants with acute partial-thickness burns of 3% to 4% total burn surface area. Participants were randomised to hydrosurgery or conventional debridement. There may be little or no difference in mean time to complete healing (mean difference (MD) 0.00 days, 95% confidence interval (CI) -6.25 to 6.25) or postoperative infection risk (risk ratio 1.33, 95% CI 0.57 to 3.11). These results are based on very low-certainty evidence, which was downgraded twice for risk of bias, once for indirectness, and once for imprecision. There may be little or no difference in operative time between hydrosurgery and conventional debridement (MD 0.2 minutes, 95% CI -12.2 to 12.6); again, the certainty of the evidence is very low, downgraded once for risk of bias, once for indirectness, and once for imprecision. There may be little or no difference in scar outcomes at six months. Health-related quality of life, resource use, and other adverse outcomes were not reported.

AUTHORS' CONCLUSIONS

This review contains one randomised trial of hydrosurgery versus conventional debridement in a paediatric population with low percentage of total body surface area burn injuries. Based on the available trial data, there may be little or no difference between hydrosurgery and conventional debridement in terms of time to complete healing, postoperative infection, operative time, and scar outcomes at six months. These results are based on very low-certainty evidence. Further research evaluating these outcomes as well as health-related quality of life, resource use, and other adverse event outcomes is required.

Vascularization is the next challenge for skin tissue engineering as a solution for burn management

Skin regeneration represents a promising line of management for patients with skin loss, including burn victims. The current approach of spraying single cells over the defective areas results in variable success rates in different centers. The modern approach is to synthesize a multilayer skin construct that is based on autologous stem cells. One of the main complications with different types of transplants is sloughing due to the absence of proper vascularization. Ensuring proper vascularization will be crucial for the integration of skin constructs with the surrounding tissues. Combination of the right cells with scaffolds of proper physico-chemical properties, vascularization can be markedly enhanced. The material effect, pore size and adsorption of certain proteins, as well as the application of appropriate growth factors, such as vascular endothelial growth factors, can have an additive effect. A selection of the most effective protocols is discussed in this review.

Recombinant human ADAMTS13 treatment and anti-NET strategies enhance skin allograft survival in mice

Enhancing skin allograft longevity lessens the need for new allografts before optimal intervention is available. Reduced activity of ADAMTS13 (an enzyme that cleaves the pro-thrombotic and proinflammatory von Willebrand factor) and presence of neutrophil extracellular traps (NETs) have been implicated in liver and lung allograft failures. The effect of ADAMTS13 treatment and the impact of NETs on skin allografts, however, remain unexplored. Here, we adopted a murine model of complete mismatch full-thickness skin transplant by grafting dorsal skin from BALB/c mice to C57BL/6J background mice. Recombinant human ADAMTS13 (rhADAMTS13) treatment of graft recipients increased allograft survival. Western blot and immunofluorescence microscopy revealed the presence of NETs in allografts of vehicle, but surprisingly, not in rhADAMTS13-treated mice, 3 days after surgery. Recapitulating the observations in mice, NETs were also observed in all the examined allografts from burn patients. Intriguingly, knocking out peptidylarginine deiminase 4 (PAD4, a key enzyme for NET formation) or DNase 1 treatment (which cleaves NETs) also prolonged allograft survival. In summary, rhADAMTS13 lessens inflammation in allografts by reducing NET burden, resulting in enhanced allograft survival. RhADAMTS13 and anti-NET treatments could be new therapeutic strategies to promote skin allograft longevity and, hence, the survival of patients with severe burns.

Patients' satisfaction with anesthesia in enzymatic debridement from a surgical perspective

INTRODUCTION

Various clinical studies found that enzymatic debridement (EDNX) is superior to tangential excision after severe burns. The current study evaluates patients' satisfaction with pain management in EDNX with special respect to different anesthesia techniques.

METHODS

Between 2015 and 2016, all patients at a department of plastic surgery were asked to complete a German-wide validated pain questionnaire. In a retrospective study design, satisfaction with pain management was compared between the control group (diagnosis from the whole field of plastic surgery except burns) and the EDNX group (burns treated with EDNX only). Analgosedation, general, regional and local anesthesia were chosen for pain management.

RESULTS

In the control group 403 patients (153 females, 250 males, medium age 53 years) could be included The EDNX group included 88 patients (20 females, 68 males, medium age 38 years). The mean burn size was 5.3% TBSA. Between 0.5%-10.5% of the surface was treated with EDNX. EDNX patients could be treated under analgosedation and regional anesthesia, by topical anesthesia creme and without any anesthesia. They reported less pain during stress (p = 0.04) and were less frequently affected by motion (p = 0.024) and nausea (<0.001). However, they felt that they need more information about alternative anesthetic treatments (<0.001).

CONCLUSION

EDNX can be performed sufficiently either under analgosedation, regional or local anesthesia. Thus, side effects of general anesthesia can be reduced and treatment costs can be decreased. However, it was found that neither after topical anesthetic creme nor after hand block pain treatment was sufficient.

Epidemiological Investigation of Elderly Patients with Severe Burns at a Major Burn Center in Southwest China

Background

The treatment of elderly patients with severe burns is difficult and the mortality rate is high. The aim of this study was to investigate the epidemiological features of elderly patients with severe burns.

Material/Methods

Data from 109 elderly patients with severe burns between January 2009 and December 2018 were retrospectively analyzed. Demographic data, clinical characteristics, treatments, and outcomes were statistically analyzed.

Results

Among the 109 elderly patients with severe burns, the male-to-female ratio was 1.73: 1.0. The median age of the elderly patients was 67 years, and the median total body surface area (TBSA) burned was 42%. Notably, 67.9% of burns occurred at home and most frequently occurred in summer (38.5%) and winter (28.4%); flame and flash burns predominated (83.4%). The incidence of inhalation injury was 35.8%, and pre-existing comorbidities were observed in approximately 51.4% of the patients. The median length of stay in the hospital per TBSA burned was 0.4 days. The mortality rate in the elderly patients was 24.8%, and the mortality rates in the ≥70% TBSA group, inhalation injury group, and patients with 3 or more pre-existing comorbidities were significantly higher than in the other groups. The risk of death increased with an increase in the number of pre-existing comorbidities (odds ratio: 2.222; 95% confidence interval: 1.174–4.205).

Conclusions

At a major burn center in Southwest China, the incidence and mortality of elderly patients with severe burns displayed no downward trend. There are etiological characteristics of these age groups that should be considered for prevention. Meanwhile, multidisciplinary treatment in a hospital and an increase in the social support for the elderly population might improve outcomes.

A 'metabolic bundle' including Oxandrolone in optimising the metabolic status of severely burn injured patients: a retrospective analysis of the first 50 patients

Objective: Severe burn injuries are associated with a rapid escalating hypermetabolic state and catabolism of muscle mass. To ameliorate this process a standardized approach using pharmacological and non-pharmacological interventions was implemented within a single burns center. Whilst individual components of this standardized package are well documented in the literature, their collective or bundled effect has not as yet been assessed. The aim of this study was to evaluate the efficacy of this standardized bundle of metabolic modulators and assess the safety of including the anabolic steroid oxandrolone within it. Methods: This retrospective observational study constituted all patients in whom the metabolic bundle including oxandrolone therapy was applied. The other elements of the metabolic bundle consisted of early surgical burn excision within seven days to completion, early active mobilization, increased ambient room temperature, expediated carbohydrate and protein rich enteral feeding with glutamine and trace element supplements (such as copper and zinc). Finally, administration of propranolol as a non-selective beta-blocker. Data collection was through review of the patient data management system focusing on the outcome criteria and hepatic blood values. Results: The study looked at fifty consecutive patients meeting the inclusion criteria. Median patient age and burned total body surface area (TBSA) were 62 years [51.75; 73] and 33.75% [24.75; 51] respectively with an abbreviated burn severity index (ABSI) of 10 [9; 10.25]. Definitive surgical burn wound excision was completed in 44 patients [88%] within 7 days. 39 patients (78%) received propranolol over a therapeutic period of 29 days [19; 44]. Glutamine was supplemented in 45 patients (90%), while zinc and copper were applied to 42 (84%) and 31 (62%) respectively. Significant low zinc values were noted at therapeutic onset (6.5 mmol/l [4.7; 7.9]) requiring sustained substitution over 37.5 days [22; 46.75]). In respect of the inclusion criteria, all patients received oxandrolone at 20 mg/day [20; 20]. This was commenced on day 6.5 [4; 14] post burn injury and continued over 26 days [19; 31]. Despite a transitory elevation of hepatic enzyme values (ALT, GGT), these were only clinically relevant (>10 µmol/l*S) in 2.4% and 4.6% of all measurements respectively. None were sufficiently of concern to merit cessation of treatment. Conclusion: The application of a standardised bundle of metabolic treatment options of severe burns injured patients is reliable, repeatable and safe. Potential concerns of oxandrolone treatment regarding hepatic compromise remain unfounded.

Neonatal Airway Management

Safe and effective airway management of neonates requires unique knowledge and clinical skills. Practitioners should have an understanding of neonatal airway anatomy and respiratory physiology and their clinical implications related to airway management. It is vital to recognize the potential sequelae of prematurity. Clinicians should be familiar with the skills and techniques available for managing normal neonatal airways. This review provides stepwise considerations for managing the neonatal airway: specific considerations for neonatal airway management, assessment and preparation, induction and premedication, and techniques and strategies for airway management in patients with normal anatomy and in patients who are difficult to intubate.

Tissue-engineered dermis grafts using stromal vascular fraction cells on the nose: A retrospective case-control study

BACKGROUND

In a previous study, our group demonstrated that cultured autologous fibroblast-seeded artificial dermis was superior to artificial dermis for covering defects after surgical excision of basal cell carcinoma (BCC) in terms of scar quality. However, utilizing cultured cells for clinical purposes requires Food and Drug Administration-approved facilities and techniques and a lengthy culture period. The purpose of this retrospective study was to compare the effects of tissue-engineered dermis containing stromal vascular fraction (SVF) cells with artificial dermis on scar quality after surgical excision of BCC on the nose.

METHODS

Between April 2010 and February 2018, patients who were treated with tissue-engineered or artificial dermis grafts and those with a follow-up period of greater than a year were included in this study. The Patient and Observer Scar Assessment Scales (POSAS) were compared between two groups according to the location of the graft, which was classified based on nasal subunits: the upper two-thirds zone; the lower one-third zone, except for the ala; and the alar zone.

RESULTS

A tissue-engineered dermis composed of SVF cells and an artificial dermis were applied to 30 and 47 patients, respectively. In upper two-thirds and lower one-third zones, except for the ala, no statistically significant differences were found in any parameters. In the alar zone, statistically significant differences were detected in 10 of 21 POSAS parameters.

CONCLUSION

To cover nasal defects, the tissue-engineered dermis graft may be superior to the artificial dermis graft regarding scar quality at the ala. However, there were no significant differences in other zones.

Clinical applications of laser speckle contrast imaging: a review

When a biological tissue is illuminated with coherent light, an interference pattern will be formed at the detector, the so-called speckle pattern. Laser speckle contrast imaging (LSCI) is a technique based on the dynamic change in this backscattered light as a result of interaction with red blood cells. It can be used to visualize perfusion in various tissues and, even though this technique has been extensively described in the literature, the actual clinical implementation lags behind. We provide an overview of LSCI as a tool to image tissue perfusion. We present a brief introduction to the theory, review clinical studies from various medical fields, and discuss current limitations impeding clinical acceptance.

The color of skin: red diseases of the skin, nails, and mucosa

Red color is pervasive in local and systemic skin conditions. It is a color that often reflects variations of dermal blood flow and extends beyond the rubor and calor of inflammation. The pathophysiology of red skin involves remote and local chemical mediators that dilate arteriolar smooth muscle and increase blood flow to superficial vessels and capillary beds. Incident light hits hemoglobin, which preferentially absorbs light of shorter wavelengths, such as blue, and reflects warmer colors. Due to its pervasiveness and consistency, red color is a useful descriptive factor in helping narrow a differential diagnosis. Red skin disorders include a variety of conditions involving endocrine mediators, cardiovascular responses, and the disruption of the skin barrier. An understanding of the blood's role in these disorders equips clinicians to generate differential diagnoses through the lens of pathophysiology. Dermatologists can improve management by considering red skin as part of systemic disease rather than as an isolated incident.

Variation in Cutaneous Patterns of Melanomagenesis According to Germline CDKN2A/CDK4 Status in Melanoma-Prone Families

CDKN2A and CDK4 are well-established melanoma susceptibility genes, but their effect on tumor location and distribution is unknown. We used a case-case study design to assess for differences in tumor location between mutation carriers (CDKN2A = 141 patients, 348 melanomas; CDK4 = 15 patients, 54 melanomas) and noncarriers (104 patients, 157 melanomas) in US melanoma-prone families. Associations between groups were assessed with chi-square tests. Odds ratios (ORs) for tumor location were adjusted for diagnosis age, gender, and superficial spreading subtype. Models included random effects to account for within individual and family correlations. Compared with having a truncal melanoma, CDK4 (vs. noncarriers: lower extremities OR = 14.5, 95% confidence interval [CI] = 5.02-42.0, P < 0.001; upper extremities OR = 6.88, 95% CI = 2.37-19.9, P < 0.001; head and neck OR = 18.6, 95% CI = 4.04-85.2, P < 0.001) and CDKN2A (vs. noncarriers: lower extremities OR = 3.01, 95% CI = 1.56-5.82, P < 0.05; upper extremities OR = 1.91, 95% CI = 1.03-3.52, P < 0.05; head and neck OR = 5.40, 95% CI = 2.10-13.9, P < 0.001) carriers had higher odds of developing melanoma at all other sites. Similar findings were observed for analyses stratified by gender, age, and first versus subsequent melanoma diagnoses. Further studies are needed to understand the biology underlying these genotype-associated patterns of tumor development, which could provide new insights into melanoma treatment and prevention.

North American clinical management guidelines for hidradenitis suppurativa: A publication from the United States and Canadian Hidradenitis Suppurativa Foundations: Part I: Diagnosis, evaluation, and the use of complementary and procedural management

Hidradenitis suppurativa is a chronic inflammatory disorder affecting hair follicles, with profoundly negative impact on patient quality of life. Evidence informing ideal evaluation and management of patients with hidradenitis suppurativa is still sparse in many areas, but it has grown substantially in the last decade. Part I of this evidence-based guideline is presented to support health care practitioners as they select optimal management strategies, including diagnostic testing, comorbidity screening, and both complementary and procedural treatment options. Recommendations and evidence grading based on the evidence available at the time of the review are provided.

Skin bioprinting: the future of burn wound reconstruction?

Burns are a significant cause of trauma, and over the years, the focus of patient care has shifted from just survival to facilitation of improved functional outcomes. Typically, burn treatment, especially in the case of extensive burn injuries, involves surgical excision of injured skin and reconstruction of the burn injury with the aid of skin substitutes. Conventional skin substitutes do not contain all skin cell types and do not facilitate recapitulation of native skin physiology. Three-dimensional (3D) bioprinting for reconstruction of burn injuries involves layer-by-layer deposition of cells along with scaffolding materials over the injured areas. Skin bioprinting can be done either in situ or in vitro. Both these approaches are similar except for the site of printing and tissue maturation. There are technological and regulatory challenges that need to be overcome for clinical translation of bioprinted skin for burn reconstruction. However, the use of bioprinting for skin reconstruction following burns is promising; bioprinting will enable accurate placement of cell types and precise and reproducible fabrication of constructs to replace the injured or damaged sites. Overall, 3D bioprinting is a very transformative technology, and its use for wound reconstruction will lead to a paradigm shift in patient outcomes. In this review, we aim to introduce bioprinting, the different stages involved, in vitro and in vivo skin bioprinting, and the various clinical and regulatory challenges in adoption of this technology.

Comparative study of conventional and topical heparin treatment in second degree burn patients for burn analgesia and wound healing

OBJECTIVE

To compare clinical outcome of topical conventional with topical heparin treatment in 2nd degree or partial thickness (PTB) burn patients.

METHODS

Patients, between the ages of 14 and 60 years with 2nd degree burns involving <20%. Total body surface area (TBSA) on front of chest, abdomen and upper limbs excluding hands and lower limbs were enrolled from September 2015 to August 2016. Patients were randomized to conventional or heparin treatment groups. Clinical outcome measured were healed wound size, pain scores and total consumption of analgesic medication required to relieve pain. Safety of the treatment and adverse events were also measured RESULTS: Out of 66 patient included in study mean (SD) age of participants was 27 (10) years, of which 59% were males. Mean (SD) TBSA burn was 14% (3) [23 (35%) had SPTB, and 43 (65%) had DPTB]. The burn injury was caused by flames in 68% and by hot liquids in 32% patients. There was no statistically significant difference in distribution of patients according to age, gender, TBSA burn, etiology or depth of burns in the two treatment groups. As compared to conventional treatment group, heparin treatment group had significantly better outcomes. Number of days needed for wound healing was significantly lower in the heparin group than the conventional group (SPTB 14±1 vs. 20±4 days; P-value <0.000 and for DPTB, 15±3 vs. 19±2 days; P-value <0.003). Mean pain score was also lower in the heparin group (for both SPTB and DPTB 3±1 vs. 7±1; P-value <0.000). Similarly, total consumption of analgesic medication was significantly less in the heparin group (53±27 vs. 119±15mg; P-value <0.000 for SPTB and 46±6 vs. 126±12mg; P-value <0.000 for DPTB). In both groups, no patient had wound infection, skin necrosis, leucopenia, thrombocytopenia, worsening renal function, or abnormal liver enzymes CONCLUSION: Treatment of second degree or partial thickness burns (PTB) with topical heparin is superior to conventional treatment in terms of wound healing as well as for pain control. The treatment with topical heparin is well-tolerated and is without higher adverse effects.

Mahalanobis Outier Removal for Improving the Non-Viable Detection on Human Injuries

Machine learning techniques have been recently applied for discriminating between Viable and Non-Viable tissues in animal wounds, to help surgeons to identify areas that need to be excised in the process of burn debridement. However, the presence of outliers in the training data set can degrade the performance of that discrimination. This paper presents an outlier removal technique based on the Mahalanobis distance to improve the accuracy detection of Non-Viable skin in human injuries. The iteratively application of this technique improves the accuracy results of the Non-Viable skin in a 13.6% when applying K-fold cross-validation.

Approaches to cutaneous wound healing: basics and future directions

The skin provides essential functions, such as thermoregulation, hydration, excretion and synthesis of vitamin D. Major disruptions of the skin cause impairment of critical functions, resulting in high morbidity and death, or leave one with life-changing cosmetic damage. Due to the complexity of the skin, diverse approaches are needed, including both traditional and advanced, to improve cutaneous wound healing. Cutaneous wounds undergo four phases of healing. Traditional management, including skin grafts and wound dressings, is still commonly used in current practice but in combination with newer technology, such as using engineered skin substitutes in skin grafts or combining traditional cotton gauze with anti-bacterial nanoparticles. Various upcoming methods, such as vacuum-assisted wound closure, engineered skin substitutes, stem cell therapy, growth factors and cytokine therapy, have emerged in recent years and are being used to assist wound healing, or even to replace traditional methods. However, many of these methods still lack assessment by large-scale studies and/or extensive application. Conceptual changes, for example, precision medicine and the rapid advancement of science and technology, such as RNA interference and 3D printing, offer tremendous potential. In this review, we focus on the basics of wound treatment and summarize recent developments involving both traditional and hi-tech therapeutic methods that lead to both rapid healing and better cosmetic results. Future studies should explore a more cost-effective, convenient and efficient approach to cutaneous wound healing. Graphical abstract Combination of various materials to create advanced wound dressings.

Controlled Delivery of a Focal Adhesion Kinase Inhibitor Results in Accelerated Wound Closure with Decreased Scar Formation

Formation of scars after wounding or trauma represents a significant health care burden costing the economy billions of dollars every year. Activation of focal adhesion kinase (FAK) has been shown to play a pivotal role in transducing mechanical signals to elicit fibrotic responses and scar formation during wound repair. We have previously shown that inhibition of FAK using local injections of a small molecule FAK inhibitor (FAKI) can attenuate scar development in a hypertrophic scar model. Clinical translation of FAKI therapy has been challenging, however, because of the lack of an effective drug delivery system for extensive burn injuries, blast injuries, and large excisional injuries. To address this issue, we have developed a pullulan collagen-based hydrogel to deliver FAKI to excisional and burn wounds in mice. Specifically, two distinct drug-laden hydrogels were developed for rapid or sustained release of FAKI for treatment of burn wounds and excisional wounds, respectively. Controlled delivery of FAKI via pullulan collagen hydrogels accelerated wound healing and reduced collagen deposition and activation of scar-forming myofibroblasts in both wound healing models. Our study highlights a biomaterial-based drug delivery approach for wound and scar management that has significant translational implications.

Advancements in Regenerative Strategies Through the Continuum of Burn Care

Burns are caused by several mechanisms including flame, scald, chemical, electrical, and ionizing and non-ionizing radiation. Approximately half a million burn cases are registered annually, of which 40 thousand patients are hospitalized and receive definitive treatment. Burn care is very resource intensive as the treatment regimens and length of hospitalization are substantial. Burn wounds are classified based on depth as superficial (first degree), partial-thickness (second degree), or full-thickness (third degree), which determines the treatment necessary for successful healing. The goal of burn wound care is to fully restore the barrier function of the tissue as quickly as possible while minimizing infection, scarring, and contracture. The aim of this review is to highlight how tissue engineering and regenerative medicine strategies are being used to address the unique challenges of burn wound healing and define the current gaps in care for both partial- and full-thickness burn injuries. This review will present the current standard of care (SOC) and provide information on various treatment options that have been tested pre-clinically or are currently in clinical trials. Due to the complexity of burn wound healing compared to other skin injuries, burn specific treatment regimens must be developed. Recently, tissue engineering and regenerative medicine strategies have been developed to improve skin regeneration that can restore normal skin physiology and limit adverse outcomes, such as infection, delayed re-epithelialization, and scarring. Our emphasis will be centered on how current clinical and pre-clinical research of pharmacological agents, biomaterials, and cellular-based therapies can be applied throughout the continuum of burn care by targeting the stages of wound healing: hemostasis, inflammation, cell proliferation, and matrix remodeling.

Merging of Classifiers for Enhancing Viable vs Non-Viable Tissue Discrimination on Human Injuries

Non-invasive optical imaging techniques have been recently proposed for distinguishing between different types of tissue in burns generated in porcine models. These techniques are designed to assist surgeons during the process of burn debridement, to identify regions requiring excision and their appropriate excision depth. This paper presents a machine learning tool for discriminating between Viable and Non- Viable tissues in human injuries. This tool merges a supervised (QDA) with an unsupervised (k-means clustering) classification algorithms. This combination improves the Non-Viable tissue detection in 23.7% with respect to a simple QDA classifier.

3D bioprinting of skin tissue: From pre-processing to final product evaluation

Bioprinted skin tissue has the potential for aiding drug screening, formulation development, clinical transplantation, chemical and cosmetic testing, as well as basic research. Limitations of conventional skin tissue engineering approaches have driven the development of biomimetic skin equivalent via 3D bioprinting. A key hope for bioprinting skin is the improved tissue authenticity over conventional skin equivalent construction, enabling the precise localization of multiple cell types and appendages within a construct. The printing of skin faces challenges broadly associated with general 3D bioprinting, including the selection of cell types and biomaterials, and additionally requires in vitro culture formats that allow for growth at an air-liquid interface. This paper provides a thorough review of current 3D bioprinting technologies used to engineer human skin constructs and presents the overall pipelines of designing a biomimetic artificial skin via 3D bioprinting from the design phase (i.e. pre-processing phase) through the tissue maturation phase (i.e. post-processing) and into final product evaluation for drug screening, development, and drug delivery applications.

Preclinical assessment of safety and efficacy of intravenous delivery of autologous adipose-derived regenerative cells (ADRCs) in the treatment of severe thermal burns using a porcine model

OBJECTIVE

A number of studies have reported that application of autologous adipose-derived cell populations leads to improved outcome in different preclinical models of thermal burn injury. However, these studies were limited to assessment of relatively small injuries amounting to only ∼2% of total body surface area (TBSA) in which the complications associated with large burns (e.g.: systemic inflammation and the need for fluid resuscitation) are absent. In anticipation of translating this approach to a clinical trial in which these complications would be present we applied a preclinical model that more closely resembles a patient with large thermal burn injury requiring skin grafting. Thus, the present study used a porcine model to investigate safety and efficacy of intravenous delivery of ADRCs in the treatment of a complex burn injury comprising ∼20% TBSA and including both moderately deep (44%) partial and full thickness burns, and the injury associated with skin graft harvest.

METHODS

Two pairs of full thickness and partial thickness burns involving in total ∼20% TBSA were created on the back of Yorkshire pigs (n=15). Three days post-burn, full thickness wounds were excised and grafted with a 3:1 meshed autologous split thickness skin graft (STSG). Partial thickness wounds were not treated other than with dressings. Animals were then randomized to receive intravenous delivery of ADRCs (n=8) or vehicle control (n=7). Safety was assessed by monitoring systemic parameters (blood gases, hematology, and clinical chemistry) throughout the course of the study. Wound healing for both types of burn wound and for the skin graft donor sites was followed for 18days using wound imaging, histology, and trans-epidermal water loss (TEWL; skin barrier function assessment).

RESULTS

No serious adverse events related to ADRC infusion were noted in any of the animals. Delivery of ADRCs appeared to be safe with none of the systemic safety parameters worsened compared to the control group. TEWL and histological analyses revealed that ADRC treatment was associated with significantly accelerated healing of skin graft (27.1% vs. 1.1% on Day 5 post-grafting), donor site (52.8% vs. 33.1% on Day 5 post-excision) and partial thickness burn (81.8% vs. 59.8% on Day 18 post-treatment). Data also suggested that ADRC treatment improved parameters associated with skin graft elasticity.

CONCLUSIONS

This study demonstrated that intravenous delivery of autologous ADRCs appears to be a safe and feasible approach to the treatment of large burns and supports the use of ADRCs as an adjunct therapy to skin grafting in patients with severe burns.