Burn-induced hypermetabolism and skeletal muscle dysfunction

HOUSING TEMPERATURE ALTERS BURN-INDUCED HYPERMETABOLISM IN MICE

ABSTRACT

Mice used in biomedical research are typically housed at ambient temperatures (22°C-24°C) below thermoneutrality (26°C-31°C). This chronic cold stress triggers a hypermetabolic response that may limit the utility of mice in modeling hypermetabolism in response to burns. To evaluate the effect of housing temperature on burn-induced hypermetabolism, mice were randomly assigned to receive sham, small, or large scald burns. Mice recovered for 21 days in metabolic phenotyping cages at 24°C or 30°C. Regardless of sex or sham/burn treatment, mice housed at 24°C had greater total energy expenditure ( P < 0.001), which was largely attributable to greater basal energy expenditure when compared to mice housed at 30°C ( P < 0.001). Thermoneutral housing (30°C) altered adipose tissue mass in a sex-dependent manner. Compared to sham and small burn groups, large burns resulted in greater water vapor loss, regardless of housing temperature ( P < 0.01). Compared to sham, large burns resulted in greater basal energy expenditure and total energy expenditure in mice housed at 24°C; however, this hypermetabolic response to large burns was blunted in female mice housed at 30°C, and absent in male mice housed at 30°C. Locomotion was significantly reduced in mice with large burns compared to sham and small burn groups, irrespective of sex or housing temperature ( P < 0.05). Housing at 30°C revealed sexual dimorphism in terms of the impact of burns on body mass and composition, where males with large burns displayed marked cachexia, whereas females did not. Collectively, this study demonstrates a sex-dependent role for housing temperature in influencing energetics and body composition in a rodent model of burn trauma.

Red blood cell distribution width at admission and the short-term mortality of patients with severe burn injury: a meta-analysis

OBJECTIVE

Red blood cell distribution width (RDW) is a marker of inflammation and oxidative stress, and its elevation has been associated with poor outcomes in critically ill patients. This meta-analysis aimed to evaluate the association between RDW at admission and short-term mortality in patients with severe burn injury.

METHODS

We systematically searched PubMed, Embase, and Web of Science up to August 2024, following PRISMA 2020 and Cochrane guidelines. Cohort studies of adult severe burn patients who reported RDW at admission and short-term mortality were included. Meta-analyses were performed using random-effects models, with mean difference (MD) and relative risk (RR) calculated for RDW and mortality outcomes, respectively. Subgroup and sensitivity analyses were conducted to assess heterogeneity.

RESULTS

Nine cohort studies involving 5268 patients were included. Overall, RDW at admission was higher in nonsurvivors compared to survivors [MD: 0.95%, 95% confidence interval (CI): 0.52-1.38, p < 0.001, I2 = 57%]. In addition, a high RDW was associated with an increased risk of short-term mortality (RR: 1.76, 95% CI: 1.41-2.19, p < 0.001, I2 = 77%). Sensitivity analyses by excluding one dataset at a time confirmed the robustness of these findings. Subgroup analyses revealed no significant differences based on clinical settings, patient age, sex, follow-up duration, or study quality.

CONCLUSIONS

RDW at admission is a significant predictor of short-term mortality in patients with severe burn injury. This finding highlights the potential role of RDW as a simple and effective marker for risk stratification in these patients.

Vitamin D administration increases serum alanine concentrations in thermally injured mice

Thermal or burn injury results in profound metabolic changes in the body. This can contribute to muscle atrophy, bone loss, as well as suppression of the immune system. While the mechanisms that underlie this hypermetabolic response remain unclear, patients with burn injury often have low circulating levels of vitamin D. Vitamin D has been shown to regulate bone formation as well as regulate muscle function. We sought to clarify the effects of vitamin D administration on skeletal muscle function following thermal injury using a mouse model. We found that thermal injury resulted in decreased vitamin D levels as well as decreased bone mineral density. Branched chain amino acid (BCAA)s levels were also significantly enhanced in the serum following burn injury. Vitamin D administration reversed the decrease in bone marrow-derived mesenchymal stem cell (BM-MSC)s observed post burn injury. Interestingly, vitamin D administration also resulted in increased tricarboxylic acid cycle (TCA) cycle metabolites in muscle which was decreased after burn conditions, enhanced the supply of alanine and glutamine in the blood which could contribute to gluconeogenesis and wound healing. Therefore, vitamin D supplementation after burn injury may have effects not only in bone metabolism, but may affect substrate metabolism in other organs/tissues.

Nutritional therapy among adult patients with severe burns: A retrospective observational study

BACKGROUND AND OBJECTIVES

The objective of this study was to examine the effects of nutritional therapy in adult patients with severe burns.

METHODS AND STUDY DESIGN

Sixty adult patients with severe burns were enrolled. Data on nutritional intake through enteral nutrition (EN) or parenteral nutrition (PN) on days 7, 14, 21, and 28 post-injury were collected. Patients were divided into target and non-target groups according to whether their energy or protein intake reached the target. Age, length of ventilation, and total bilirubin (TBIL), albumin (ALB), prealbumin (pALB), and C-reactive protein (CRP) concentrations of patients were recorded.

RESULTS

The percentage of protein targets with protein delivery was lower than that of energy target with energy delivery. The ratio of PN protein to total protein was lower than that of PN energy to total energy on days 7, 14, 21, and 28 (p<0.001, p<0.001, p=0.001, and p=0.003, respectively). Compared to the non-target group on day 21, the target group was younger, had lower TBIL on day 7, higher ALB and pALB on day 21, and lower CRP on day 14 (p=0.025, p=0.021, p=0.028, p=0.029, and p=0.049, respectively). Multivariate logistic regression analysis showed that older age and longer ventilation were independent risk factors in patients who did not meet the nutritional target on day 21 (p=0.026 and p=0.043, respectively).

CONCLUSIONS

The protein intake of adult patients with severe burns was low. Compared to the non-target group, the target group had better laboratory test results. Older age and longer ventilation were independent risk factors for patients not meeting the nutritional target.

Hyperactive browning and hypermetabolism: potentially dangerous element in critical illness

Brown/beige adipose tissue has attracted much attention in previous studies because it can improve metabolism and combat obesity through non-shivering thermogenesis. However, recent studies have also indicated that especially in critical illness, overactivated brown adipose tissue or extensive browning of white adipose tissue may bring damage to individuals mainly by exacerbating hypermetabolism. In this review, the phenomenon of fat browning in critical illness will be discussed, along with the potential harm, possible regulatory mechanism and corresponding clinical treatment options of the induction of fat browning. The current research on fat browning in critical illness will offer more comprehensive understanding of its biological characteristics, and inspire researchers to develop new complementary treatments for the hypermetabolic state that occurs in critically ill patients.

Higher energy delivery is associated with improved long-term survival among adults with major burn injury: A multicenter, multinational, observational study

BACKGROUND

Numerous feeding strategies have been used to mitigate the catabolism of major burn injury. Whether higher energy and/or protein delivery results in better long-term outcomes is unknown.

METHODS

We performed a secondary analysis of data from adults with major burn injuries enrolled in the Randomized Trial of Enteral Glutamine to Minimize the Effects of Burn Injury at 54 burn centers in 18 countries. The sample was restricted to those who were mechanically ventilated within 72 hours of injury and for ≥7 days. Our key exposure was adequacy of energy, and protein ([Delivered i /Prescribed i ] × 100) was categorized into three groups each: low, 0% to 50%; moderate, ≥50% to 79%; and high, ≥80%. We also analyzed adequacy using restricted cubic splines. Primary and secondary outcomes included 6-month mortality and functional outcomes (i.e., 36-Item Short-Form Health Survey, Katz Index of Independence in Activities of Daily Living, Lawton Activities of Daily Living scores), respectively. Regression models were adjusted for age, body mass index, Charlson Comorbidity Index, baseline Acute Physiology and Chronic Health Evaluation II and modified Sequential Organ Failure Assessment scores, burn size, energy/protein adequacy, and study site.

RESULTS

A total of 493 participants met the cohort restriction criteria; 336 participants were alive at 6 months. 36-Item Short-Form Health Survey, Katz Index of Independence in Activities of Daily Living, and Lawton Instrumental Activities of Daily Living Scale were completed by 218, 216, and 215 participants, respectively. The mean ± SD age was 48 ± 17 years, and 74% were male. The mean ± SD burn size was 41% ± 18% total body surface area. Participants who received 25% of recommended calories had nearly four times the hazard of death during the 6-month follow-up period than participants who received 100% of prescribed calories (adjusted hazard ratio, 3.89; 95% confidence interval, 1.35-11.20) ( p = 0.02). There was no significant association between protein and 6-month mortality or energy/protein delivery and 6-month functional outcomes.

CONCLUSION

There was a positive association between higher doses of energy and 6-month survival. This relationship conflicts somewhat with several energy studies among critically ill and non-burn-injured patients. The lack of consistent evidence on optimal nutrition for critically injured patients, a fundamental component of burn care, suggests potential for a randomized trial of lower versus higher energy to improve long-term outcomes after burn injury.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level III.

Mild burn amplifies the locomotive depression in demyelinated mice without muscle pathophysiological changes

INTRODUCTION

Patients with mild burns take most accounts, however, the impact of mild burns is less known. Nerve destruction leads to muscle atrophy. We posit that even mild burn injury could worsen demyelinated nerves related to muscle pathophysiological impairment.

METHODS

Young adult C57BL/6 (male, n = 60) mice were randomly fed with either a 0.2% cuprizone diet or a regular rodent diet for 4 weeks. At week 5, all mice were then grouped into mild scald burn with 10% TBSA and sham injury groups. Mice received animal behavior tests and in situ muscle isometric force measurement before euthanasia for tissue collection.

RESULTS

Total horizontal ambulation and vertical activity were significantly reduced in mice with mild burn injury (p<0.05). Mice with the cuprizone diet had significantly less time to fall than those with the regular diet on day 7 after burn (p<0.05). No significant difference was found in gastrocnemius tissue weight among the groups, nor muscle isometric tensions (all p>0.05). The cuprizone diet increased the maximal phosphorylating respiration in mice muscle mitochondria (p<0.05). The muscle protein expressions of caspase 3, Fbx-32, and Murf1 significantly increased in mice with the cuprizone diet 3 days after burn (p<0.05). The signal expression of S100B significantly increased in mice with the cuprizone diet, and its expression was even greater on day 7 after burn injury. (p<0.05).

CONCLUSION

The cuprizone diet-induced locomotion and cognitive disorders were amplified by the mild burn injury in mice, which is associated with muscle intracellular signal alterations. However, mild burn injury does not cause mouse muscle weight loss and function impairment. The potential risk of pre-existed neural impairment could be aware when patients encounter even small or mild burns.

Glutamine promotes the proliferation of intestinal stem cells via inhibition of TP53-induced glycolysis and apoptosis regulator promoter methylation in burned mice

Background

Intestinal stem cells (ISCs) play a pivotal role in maintaining intestinal homeostasis and facilitating the restoration of intestinal mucosal barrier integrity. Glutamine (Gln) is a crucial energy substrate in the intestine, promoting the proliferation of ISCs and mitigating damage to the intestinal mucosal barrier after burn injury. However, the underlying mechanism has not yet been fully elucidated. The objective of this study was to explore the mechanism by which Gln facilitates the proliferation of ISCs.

Methods

A mouse burn model was established to investigate the impact of Gln on intestinal function. Subsequently, crypts were isolated, and changes in TP53-induced glycolysis and apoptosis regulator (TIGAR) expression were assessed using real-time quantitative polymerase chain reaction (RT-qPCR), western blotting, immunohistochemistry, and immunofluorescence. The effects of TIGAR on cell proliferation were validated through CCK-8, EdU, and clonogenicity assays. Furthermore, the effect of TIGAR on Yes-associated protein (YAP) nuclear translocation and ferroptosis was examined by western blotting and immunofluorescence staining. Finally, dot blot analysis and methylation-specific PCR were performed to evaluate the effect of Gln on TIGAR promoter methylation.

Results

The mRNA and protein levels of TIGAR decreased after burn injury, and supplementation with Gln increased the expression of TIGAR. TIGAR accelerates the nuclear translocation of YAP, thereby increasing the proliferation of ISCs. Concurrently, TIGAR promotes the synthesis of nicotinamide adenine dinucleotide phosphate (NADPH) and glutathione to suppress ferroptosis in ISCs. Subsequent investigations demonstrated that Gln inhibits TIGAR promoter methylation by increasing the expression of the demethylase ten-eleven translocation. This change increased TIGAR transcription, increased NADPH synthesis, and reduced oxidative stress, thereby facilitating the restoration of intestinal mucosal barrier integrity post-burn injury.

Conclusions

Our data confirmed the inhibitory effect of Gln on TIGAR promoter methylation, which facilitates YAP translocation into the nucleus and suppresses ferroptosis, ultimately promoting the proliferation of ISCs.

Esophageal chemical burns as a risk factor for esophageal malignancies: in-silico analyses - experimental research

Introduction

Esophageal chemical burns often occur through accidental or intentional oral consumption of chemical agents and lead to severe complications such as esophageal stricture, acute perforation, and even death. Esophageal squamous cell carcinoma is a squamous epithelium tumor that lines the normal esophagus. Additionally, adenocarcinomas are tumors located at the interface between the distal esophagus and the proximal gastric and divided into esophageal adenocarcinoma and gastric-cardia adenocarcinoma. Various conditions, such as chemical burns, are considered risk factors in the disease's pathogenesis. In the in-silico study, the authors aim to present the relationship between chemical burns and esophageal cancer by analyzing bioinformatics genetic data.

Methods

The proper gene set was extracted using the 'GEO' database. The string web tool was utilized to form the gene-interaction network. Gephi and Cytoscape software were applied to achieve network analysis.

Results

According to in-silico data, 26 genes, including NCAPH, DLGAP5, CCNB1, KIF11, KIAA0101, CDCA5, BIRC5, NUF2, BUB1B, RRM2, TTK, CDC20, NUSAP1, CCNB2, CCNA2, MELK, TPX2, PRC1, KIF4A, CENPF, TOP2A, CDK1, ASPM, CEP55, BUB1, KIF20A were extracted that can be regarded as the most critical shared genes between chemical burns and esophageal cancer.

Conclusion

In sum, esophageal chemical burns can be related to the occurrence of esophageal cancer. Moreover, esophageal chemical burn is an external factor that upregulates present genes and can be regarded as a worsening prognosis or risk factor for esophageal cancer.

Chemical burn wounds as a risk factor for gastric cancer: in-silico analyses-experimental research

Introduction

The present study employs bioinformatics tools to identify shared upregulated genes between chemical burns and gastric cancer.

Methods

Gene Expression Omnibus (GEO) retrieved gene sets for this investigation. GSEs with P value less than 0.05 and LOG fold change (FC) greater than 1 were valid and upregulated. Gastric cancer and chemical burn common elevated genes were found using Venn diagram online tools. In the second stage, the "string" visualized gastric cancer elevated genes network, and non-coding RNAs were deleted, and "interaction" greater than 1 was examined to choose important gene nodes. Next, they explored the String gene-interaction network for common genes. To determine the most interacting genes, Gephi (V 0.9.7) used "betweenness centrality" greater than "0" to evaluate the twenty-gene network. TISIDB and drug banks provide gene-related medications.

Results

In the present study, two genes, including ALOX5AP and SERPINB2, were obtained, with the highest centrality among chemical burns and gastric cancer shared genes. Additionally, the current study presented five drugs, including Urokinase, Tenecteplase, DG031, AM103, and Fiboflapon, which can have predicted effects on gastric cancer following chemical burns.

Conclusion

According to current in-silicon analyses, ALOX5AP and SERPINB2 are linked genetic keys between gastric chemical burn and cancer. Considering that burn is an environmental factor that leads to the upregulation of the two genes thus, the chemical burn can be related to the incidence of gastric cancer.

Pathophysiology of Severe Burn Injuries: New Therapeutic Opportunities From a Systems Perspective

Severe burn injury elicits a profound stress response with the potential for high morbidity and mortality. If polytrauma is present, patient outcomes appear to be worse. Sex-based comparisons indicate females have worse outcomes than males. There are few effective drug therapies to treat burn shock and secondary injury progression. The lack of effective drugs appears to arise from the current treat-as-you-go approach rather than a more integrated systems approach. In this review, we present a brief history of burns research and discuss its pathophysiology from a systems' perspective. The severe burn injury phenotype appears to develop from a rapid and relentless barrage of damage-associated molecular patterns, pathogen-associated molecular patterns, and neural afferent signals, which leads to a state of hyperinflammation, immune dysfunction, coagulopathy, hypermetabolism, and intense pain. We propose that if the central nervous system control of cardiovascular function and endothelial-glycocalyx-mitochondrial coupling can be restored early, these secondary injury processes may be minimized. The therapeutic goal is to switch the injury phenotype to a healing phenotype by reducing fluid leak and maintaining tissue O2 perfusion. Currently, no systems-based therapies exist to treat severe burns. We have been developing a small-volume fluid therapy comprising adenosine, lidocaine, and magnesium (ALM) to treat hemorrhagic shock, traumatic brain injury, and sepsis. Our early studies indicate that the ALM therapy holds some promise in supporting cardiovascular and pulmonary functions following severe burns. Future research will investigate the ability of ALM therapy to treat severe burns with polytrauma and sex disparities, and potential translation to humans.

Effects of rehabilitation treatments jointly considered by physiatrists and rehabilitation therapists in patients with severe burn injury

Rehabilitation treatments for patients with severe burn injury (SBI) are difficult owing to the lack of knowledge, skills, and experience among clinicians and physical and occupational therapists, resulting in serious patient disability. This study retrospectively evaluated the effectiveness of rehabilitation treatments jointly considered by physiatrists and rehabilitation therapists (Physiatrist and Registered therapist Operating rehabilitation: PROr) for patients with SBI admitted to our hospital's burn intensive care unit (BICU). Eligible patients were classified into the PROr and standard rehabilitation (SR) groups. Contents of the rehabilitation program in the BICU, the functional ambulation categories (FAC), and the Barthel index at the first rehabilitation, BICU discharge, and hospital discharge were collected. Of the 184 patients with severe burns admitted to the BICU, 29 (PROr group, n = 16; SR group, n = 13) met the eligibility criteria. The PROr group received more types of exercise interventions for a longer time than the SR group. No significant differences in the FAC and Barthel index scores at the first time of rehabilitation were found between the two groups; however, the scores of FAC and Barthel index at BICU and hospital discharges were higher in the PROr group than in the SR group. The PROr program may help in the functional improvement of patients with SBI.

The correlation of BMI and insulin resistance in moderately burned patients

<b>Introduction:</b> Obesity is strongly related to serious comorbidities that might affect the healing process. Elevated Body Mass Index (BMI) and insulin resistance have a significant impact on the development of the metabolic syndrome often leading to lethal cardiovascular complications.<b>Aim:</b> The aim of the study was to verify the correlation of BMI and insulin resistance with clinical parameters of moderately burned patients.<b>Materials and methods:</b> There were 149 patients enrolled in the study and their clinical data was retrospectively analyzed. The laboratory tests, insulin demand, BMI, and surgical procedures were evaluated on admission and discharge.<b>Results:</b> Burned patients who required insulin were characterized by worse laboratory results on admission to the burn unit, they had lower hemoglobin (HGB) levels (P = 0.0001), higher creatinine levels by 0.323 units (P = 0.009), higher C-reactive protein (CRP) by approximately 94 units (P = 0.0001), as higher procalcitonin (PCT) by approximately 0.5 units (P = 0.001) as compared to non-insulin-treated patients. Moreover, burned patients who required insulin stayed in the hospital for an average of 10 days longer. All patients from the insulin-demand subgroup had elevated triglycerides (Tg) levels on admission with increased indexes of insulin resistance.<b>Discussion:</b> Our study suggests that the protective effect of a higher BMI in burned patients, known as the 'obesity paradox' may be compromised by insulin resistance.<b>Conclusions and significance of the study:</b> The results show that elevated Tg on admission to the burn unit coexisting with a BMI over 25 kg/m² may be used as an important prognostic factor and may help with prediction of insulin demand and worse outcome in moderately burned patients.

Prediction of immune molecules activity during burn wound healing among elderly patients: in-silico analyses: experimental research

Introduction

Burn injuries lead to dysregulation of immune molecules, impacting cellular and humoral immune pathways. This study aims to determine the prediction of immune molecule activity during burn wound healing among elderly patients.

Methods

The current study utilized the Gene Expression Omnibus (GEO) database to extract the proper gene set. Also, the literature review was conducted in the present study to find immune signatures. The study used the "enrich r" website to identify the biological functions of extracted genes. The critical gene modules related to mortality were identified using the weighted gene co-expression network analysis (WGCNA) R package.

Results

The appreciated GSE was extracted. According to the data, the most upregulated signatures were related to natural killer (NK) cells, and the most downregulated signatures were associated with M1 macrophages. Also, the results of WGCNA have shown that the most related gene modules (P<107 and score 0.17) to mortality were investigated, and the modules 100 first genes were extracted. Additionally, the enrich r analysis has demonstrated related pathways, including the immune process, including regulation of histamine secreted from mast cell (P<0.05), T helper 17 cell differentiation (P<0.05), and autophagy (P<0.05) were obtained. Finally, by network analysis, the critical gene "B3GNT5" were obtained (degree>ten and "betweenness and centrality">30 were considered).

Conclusion

The study identified significant changes in macrophage and NK cell expression patterns post-burn injury, linking them to potential improvements in clinical outcomes and wound healing. The gene B3GNT5, associated with mortality, was highlighted as a key marker for prognostic evaluation.

1H-nuclear magnetic resonance analysis reveals dynamic changes in the metabolic profile of patients with severe burns

Background

Severe burn injury causes a hypermetabolic response, resulting in muscle protein catabolism and multiple organ damage syndrome. However, this response has not yet been continuously characterized by metabolomics in patients. This study aims to quantify temporal changes in the metabolic processes of patients with severe burns.

Methods

We employed 1H-nuclear magnetic resonance (NMR) spectroscopy to scrutinize metabolic alterations during the initial 35 days following burn injury in a cohort of 17 adult patients with severe burns, with 10 healthy individuals included as controls. Plasma specimens were collected from patients on postburn days 1, 3, 7, 14, 21, 28 and 35. After performing multivariate statistical analysis, repeated-measures analysis of variance and time-series analysis, we quantified changes in metabolite concentrations.

Results

Among the 36 metabolites quantified across 119 samples from burn patients, branched-chain amino acids, glutamate, glycine, glucose, pyruvate, lactate, trimethylamine N-oxide and others exhibited obvious temporal variations in concentration. Notably, these metabolites could be categorized into three clusters based on their temporal characteristics. The initial response to injury was characterized by changes in lactate and amino acids, while later changes were driven by an increase in fatty acid catabolism and microbial metabolism, leading to the accumulation of ketone bodies and microbial metabolites.

Conclusions

Metabolomics techniques utilizing NMR have the potential to monitor the intricate processes of metabolism in patients with severe burns. This study confirmed that the third day after burn injury serves as the boundary between the ebb phase and the flow phase. Furthermore, identification of three distinct temporal patterns of metabolites revealed the intrinsic temporal relationships between these metabolites, providing clinical data for optimizing therapeutic strategies.

The Use of Oxandrolone in the Management of Severe Burns: A Multi-service Survey of Burns Centres and Units Across the United Kingdom

Introduction Severe thermal burns are a catastrophic injury. Those surviving the initial insult are subject to life-long disability, prolonged hospital admission, nutritional issues and poor wound healing. Oxandrolone has been shown to reduce hospital duration and promote lean body mass. Despite not being licenced for use in burns trauma within the United Kingdom (UK), services across the country utilise Oxandrolone in the management of severe burns. We aim to analyse the use of Oxandrolone in major burns across burns services within the UK. Methods We conducted a survey across all burn centres and units across the UK. Any burns service provider with experience in patient management of patients sustaining burns with a total body surface area >15% was included. All services were identified using the British Burns Association website. We conducted a survey of all centres and units and contacted them via telephone through the trust's switchboard. Responses were accepted from any healthcare staff familiar with the day-to-day in-patient care of patients on the ward. Services with no in-patient services were excluded. Results A total of 24 burns centres and services responded to our survey. Twelve of the respondents were in a burns unit and 12 were in a burns centre. Eight respondents were paediatric facilities, and the remaining 16 dealt with adult burns. In total, 16/24 (66.6%) services reported using Oxandrolone. Conversely, 8/24 (33.3%) burns services denied using Oxandrolone. 7/12 (58.3%) burns units use Oxandrolone in the management of burns. 5/12 (42.7%) burns units do not use Oxandrolone in severe burns. 9/12 (75%) of burns centres described using Oxandrolone, whilst the remaining 3/12 (25%) did not.  Discussion Oxandrolone is used varyingly across burns services across the UK. Burns centres were more likely to use Oxandrolone compared to units. We also find that more paediatric services used Oxandrolone in comparison to adult services. Studies have shown that the benefit of Oxandrolone is not age-dependent. Further work is required to assess the impact of this medication on patients with severe burns and national guidance would help further improve burns management across the UK.

Subcutaneous white adipose tissue independently regulates burn-induced hypermetabolism via immune-adipose crosstalk

Severe burns induce a chronic hypermetabolic state that persists well past wound closure, indicating that additional internal mechanisms must be involved. Adipose tissue is suggested to be a central regulator in perpetuating hypermetabolism, although this has not been directly tested. Here, we show that thermogenic adipose tissues are activated in parallel to increases in hypermetabolism independent of cold stress. Using an adipose tissue transplantation model, we discover that burn-derived subcutaneous white adipose tissue alone is sufficient to invoke a hypermetabolic response in a healthy recipient mouse. Concomitantly, transplantation of healthy adipose tissue alleviates metabolic dysfunction in a burn recipient. We further show that the nicotinic acetylcholine receptor signaling pathway may mediate an immune-adipose crosstalk to regulate adipose tissue remodeling post-injury. Targeting this pathway could lead to innovative therapeutic interventions to counteract hypermetabolic pathologies.

Large area fractional laser treatment of mouse skin increases energy expenditure

Fractional laser (FL) treatment is a common dermatologic procedure that generates arrays of microscopic treatment zones separated by intact tissue, promoting fast wound healing. Using a mouse model, we introduced a large area fractional laser treatment (LAFLT) method to study metabolic effects. Using two laser modalities, ablative FL (AFL) and non-ablative FL (NAFL), and exposing different percentages of mice's total body surface area (TBSA), we followed changes in metabolic parameters in real time using metabolic cages. Additionally, body composition, markers of inflammation, neurohormonal signaling, and browning of adipocytes were investigated. LAFLT, especially in high TBSA groups, had specific metabolic effects such as significantly increased average daily energy expenditure, increased fat mass loss, systemic browning of adipocytes, and inflammatory states, without compromising other organs. The ability of LAFLT to stimulate metabolism in a controlled way could develop into a promising therapeutic treatment to induce positive metabolic changes that replace or augment systemic drugs.

Mechanism and application of β-adrenoceptor blockers in soft tissue wound healing

Soft tissue damage stimulates sympathetic nerves to release large amounts of catecholamine hormones which bind to β-adrenergic receptors (β-ARs) on the cell membrane surface. It activates the downstream effector molecules and impairs soft tissue wound healing. β-blockers specifically inhibit β-ARs activation in acute/chronic skin lesions and ulcerative hemangiomas. They also accelerate soft tissue wound healing by shortening the duration of inflammation, speeding keratinocyte migration and reepithelialization, promoting wound contraction and angiogenesis, and inhibiting bacterial virulence effects. In addition, β-blockers shorten wound healing periods in patients with severe thermal damage by reducing the hypermetabolic response. While β-blockers promote/inhibit corneal epithelial cell regeneration and restores limbal stem/progenitor cells function, it could well accelerate/delay corneal wound healing. Given these meaningful effects, a growing number of studies are focused on examining the efficacy and safety of β-blockers in soft tissue wound repair, including acute and chronic wounds, severe thermal damage, ulcerated infantile hemangioma, corneal wounds, and other soft tissue disorders. However, an intensive investigation on their acting mechanisms is imperatively needed. The purpose of this article is to summerize the roles of β-blockers in soft tissue wound healing and explore their clinical applications.

The timing of death in burn patients

Aim

When treating burn patients, some patients die in the chronic phase, even if they overcome the acute phase of the burn. To elucidate the timing of death and its underlying causes among burn patients.

Methods

Patients evaluated were admitted to our burn center between January 2015, and December 2019. Patient information, time, and cause of death were retrospectively collected from their medical records.

Results

Among 342 admitted patients, 49 died. The time of death was as follows: within 24 h (n = 9), within 3 days (n = 7), within 1 week (n = 5), within 2 weeks (n = 4), within 3 weeks (n = 3), within 30 days (n = 6), within 60 days (n = 5), and after 60 days (n = 9). The causes of death within 3 days were hypoxic encephalopathy, extensive burns (>80%), severe heat stroke, and acute coronary syndrome. The causes of death after 3 days were sepsis, pneumonia, intestinal ischemia, pancreatitis, and worsening of chronic diseases. The mortality rate was similar for patients ≥65 years of age and those with a burn area of ≥20%, with both groups showing a particularly poor prognosis.

Conclusions

The timing of death in hospitalized burn patients showed a bimodal distribution as approximately 40% of patients who survived the resuscitation period died after 30 days. Elderly patients were at particularly high risk for mortality. In burn care, treatment planning should consider not only the short-term but also the long-term prognosis.

A Narrative Review of Outcomes in Burn Rehabilitation Based on the International Classification of Functioning, Disability, and Health

Burn injury commonly causes long-term physical impairments and psychosocial limitations that impact survivorship. This article uses the World Health Organization (WHO) International Classification of Functioning, Disability and Health (ICF) framework to summarize burn rehabilitation outcomes related to body functions and structures and how they relate to activities and participation within the social context. This article will contribute to a better understanding of burn recovery, facilitate the identification of specific and meaningful issues common to burn survivorship that may be under-reported in prior investigations and guide future rehabilitation to advance long-term burn outcomes.

Updates in SJS/TEN: collaboration, innovation, and community

Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS/TEN) is a predominantly drug-induced disease, with a mortality rate of 15-20%, that engages the expertise of multiple disciplines: dermatology, allergy, immunology, clinical pharmacology, burn surgery, ophthalmology, urogynecology, and psychiatry. SJS/TEN has an incidence of 1-5/million persons per year in the United States, with even higher rates globally. One of the challenges of SJS/TEN has been developing the research infrastructure and coordination to answer questions capable of transforming clinical care and leading to improved patient outcomes. SJS/TEN 2021, the third research meeting of its kind, was held as a virtual meeting on August 28-29, 2021. The meeting brought together 428 international scientists, in addition to a community of 140 SJS/TEN survivors and family members. The goal of the meeting was to brainstorm strategies to support the continued growth of an international SJS/TEN research network, bridging science and the community. The community workshop section of the meeting focused on eight primary themes: mental health, eye care, SJS/TEN in children, non-drug induced SJS/TEN, long-term health complications, new advances in mechanisms and basic science, managing long-term scarring, considerations for skin of color, and COVID-19 vaccines. The meeting featured several important updates and identified areas of unmet research and clinical need that will be highlighted in this white paper.

Acute muscle mass loss was alleviated with HMGB1 neutralizing antibody treatment in severe burned rats

Burn injury is associated with muscle wasting, though the involved signaling mechanisms are not well understood. In this study, we aimed to examine the role of high mobility group box 1 (HMGB1) in signaling hyper-inflammation and consequent skeletal muscle impairment after burn. Sprague Dawley rats were randomly assigned into three groups: (1) sham burn, (2) burn, (3) burn/treatment. Animals in group 2 and group 3 received scald burn on 30% of total body surface area (TBSA) and immediately treated with chicken IgY and anti-HMGB1 antibody, respectively. Muscle tissues and other samples were collected at 3-days after burn. Body mass and wet/dry weights of the hind limb muscles (total and individually) were substantially decreased in burn rats. Acute burn provoked the mitochondrial stress and cell death and enhanced the protein ubiquitination and LC3A/B levels that are involved in protein degradation in muscle tissues. Further, an increase in muscle inflammatory infiltrate associated with increased differentiation, maturation and proinflammatory activation of bone marrow myeloid cells and αβ CD4+ T and γδ T lymphocytes was noted in in circulation and spleen of burn rats. Treatment with one dose of HMGB1 neutralizing antibody reduced the burn wound size and preserved the wet/dry weights of the hind limb muscles associated with a control in the markers of cell death and autophagy pathways in burn rats. Further, anti-HMGB1 antibody inhibited the myeloid and T cells inflammatory activation and subsequent dysregulated inflammatory infiltrate in the muscle tissues of burn rats. We conclude that neutralization of HMGB1-dependent proteolytic and inflammatory responses has potential beneficial effects in preventing the muscle loss after severe burn injury.

Long-Term Effects of Severe Burns on the Kidneys: Research Advances and Potential Therapeutic Approaches

Burns are a seriously underestimated form of trauma that not only damage the skin system but also cause various complications, such as acute kidney injury (AKI). Recent clinical studies have shown that the proportion of chronic kidney diseases (CKD) in burn patients after discharge is significantly higher than that in the general population, but the mechanism behind this is controversial. The traditional view is that CKD is associated with hypoperfusion, AKI, sepsis, and drugs administered in the early stages of burns. However, recent studies have shown that burns can cause long-term immune dysfunction, which is a high-risk factor for CKD. This suggests that burns affect the kidneys more than previously recognized. In other words, severe burns are not only an acute injury but also a chronic disease. Neglecting to study long-term kidney function in burn patients also results in a lack of preventive and therapeutic methods being developed. Furthermore, stem cells and their exosomes have shown excellent comprehensive therapeutic properties in the prevention and treatment of CKD, making them increasingly the focus of research attention. Their engineering strategy further improved the therapeutic performance. This review will focus on the research advances in burns on the development of CKD, illustrating the possible mechanism of burn-induced CKD and introducing potential biological treatment options and their engineering strategies.

Inflammation and Organ Injury the Role of Substance P and Its Receptors

Tightly controlled inflammation is an indispensable mechanism in the maintenance of cellular and organismal homeostasis in living organisms. However, aberrant inflammation is detrimental and has been suggested as a key contributor to organ injury with different etiologies. Substance P (SP) is a neuropeptide with a robust effect on inflammation. The proinflammatory effects of SP are achieved by activating its functional receptors, namely the neurokinin 1 receptor (NK1R) receptor and mas-related G protein-coupled receptors X member 2 (MRGPRX2) and its murine homolog MRGPRB2. Upon activation, the receptors further signal to several cellular signaling pathways involved in the onset, development, and progression of inflammation. Therefore, excessive SP-NK1R or SP-MRGPRX2/B2 signals have been implicated in the pathogenesis of inflammation-associated organ injury. In this review, we summarize our current knowledge of SP and its receptors and the emerging roles of the SP-NK1R system and the SP-MRGPRX2/B2 system in inflammation and injury in multiple organs resulting from different pathologies. We also briefly discuss the prospect of developing a therapeutic strategy for inflammatory organ injury by disrupting the proinflammatory actions of SP via pharmacological intervention.

Burns: Classification, Pathophysiology, and Treatment: A Review

Burns and their treatment are a significant medical problem. The loss of the physical barrier function of the skin opens the door to microbial invasion and can lead to infection. The repair process of the damage caused by the burn is impaired due to the enhanced loss of fluids and minerals through the burn wound, the onset of hypermetabolism with the concomitant disruption of nutrient supply, and derangements in the endocrine system. In addition, the initiated inflammatory and free radical processes drive the progression of oxidative stress, the inhibition of which largely depends on an adequate supply of antioxidants and minerals. Clinical experience and research provide more and more data to make the treatment of patients with thermal injury increasingly effective. The publication discusses disorders occurring in patients after thermal injury and the methods used at various stages of treatment.

Vitamin A Induced Hypercalcemia in Burn Patients: A Case Study

Vitamin and steroid supplementation such as oxandrolone are commonly given to speed the recovery process in severe burn injuries. Vitamin A is administered concurrently with steroids because of its pro-inflammatory and positive effects on wound healing. However, vitamin A supplementation warrants caution as hypercalcemia can result from vitamin A overdose. Our case involves an 18-year-old male injured in an oil field explosion who presented with 55% total body surface area partial and full thickness burns. Following successful resuscitation, he was given vitamin A, oxandrolone, vitamin C, and zinc sulfate as part of the standard vitamin supplementation. On hospital day 33, serum calcium levels were noted to be elevated and increased to 13 mg/dL a few days later. Parathyroid hormone and vitamin D levels were found to be within normal range, and urine analysis showed normal calcium excretion. Subsequent assessment of vitamin A levels revealed significantly elevated levels at 93 mcg/dL. Vitamin A supplementation was discontinued, and the patient was discharged on hospital day 42. At the one-month follow-up, serum calcium levels were normal, which links the hypercalcemia to vitamin A overdose. This case highlights the importance of considering vitamin A overdose as a cause for asymptomatic hypercalcemia with a normal parathyroid and vitamin D workup. While routine, vitamin A supplementation in burn patients calls for assessment of both serum calcium and vitamin A levels throughout the hospital stay to prevent hypercalcemia and its negative effects.

Disuse-induced skeletal muscle atrophy in disease and non-disease states in humans: mechanisms, prevention, and recovery strategies

Decreased skeletal muscle contractile activity (disuse) or unloading leads to muscle mass loss, also known as muscle atrophy. The balance between muscle protein synthesis (MPS) and muscle protein breakdown (MPB) is the primary determinant of skeletal muscle mass. A reduced mechanical load on skeletal muscle is one of the main external factors leading to muscle atrophy. However, endocrine and inflammatory factors can act synergistically in catabolic states, amplifying the atrophy process and accelerating its progression. Additionally, older individuals display aging-induced anabolic resistance, which can predispose this population to more pronounced effects when exposed to periods of reduced physical activity or mechanical unloading. Different cellular mechanisms contribute to the regulation of muscle protein balance during skeletal muscle atrophy. This review summarizes the effects of muscle disuse on muscle protein balance and the molecular mechanisms involved in muscle atrophy in the absence or presence of disease. Finally, a discussion of the current literature describing efficient strategies to prevent or improve the recovery from muscle atrophy is also presented.