Comprehensive Lipidomic Workflow for Multicohort Population Phenotyping Using Stable Isotope Dilution Targeted Liquid Chromatography-Mass Spectrometry.

Dysregulated lipid metabolism underpins many chronic diseases including cardiometabolic diseases. Mass spectrometry-based lipidomics is an important tool for understanding mechanisms of lipid dysfunction and is widely applied in epidemiology and clinical studies. With ever-increasing sample numbers, single batch acquisition is often unfeasible, requiring advanced methods that are accurate and robust to batch-to-batch and interday analytical variation. Herein, an optimized comprehensive targeted workflow for plasma and serum lipid quantification is presented, combining stable isotope internal standard dilution, automated sample preparation, and ultrahigh performance liquid chromatography-tandem mass spectrometry with rapid polarity switching to target 1163 lipid species spanning 20 subclasses. The resultant method is robust to common sources of analytical variation including blood collection tubes, hemolysis, freeze-thaw cycles, storage stability, analyte extraction technique, interinstrument variation, and batch-to-batch variation with 820 lipids reporting a relative standard deviation of <30% in 1048 replicate quality control plasma samples acquired across 16 independent batches (total injection count = 6142). However, sample hemolysis of ≥0.4% impacted lipid concentrations, specifically for phosphatidylethanolamines (PEs). Low interinstrument variability across two identical LC-MS systems indicated feasibility for intra/inter-lab parallelization of the assay. In summary, we have optimized a comprehensive lipidomic protocol to support rigorous analysis for large-scale, multibatch applications in precision medicine. The mass spectrometry lipidomics data have been deposited to massIVE: data set identifiers MSV000090952 and 10.25345/C5NP1WQ4S.

Nonsevere Burn Induces a Prolonged Systemic Metabolic Phenotype Indicative of a Persistent Inflammatory Response Postinjury.

Globally, burns are a significant cause of injury that can cause substantial acute trauma as well as lead to increased incidence of chronic comorbidity and disease. To date, research has primarily focused on the systemic response to severe injury, with little in the literature reported on the impact of nonsevere injuries (<15% total burn surface area; TBSA). To elucidate the metabolic consequences of a nonsevere burn injury, longitudinal plasma was collected from adults (n = 35) who presented at hospital with a nonsevere burn injury at admission, and at 6 week follow up. A cross-sectional baseline sample was also collected from nonburn control participants (n = 14). Samples underwent multiplatform metabolic phenotyping using 1H nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry to quantify 112 lipoprotein and glycoprotein signatures and 852 lipid species from across 20 subclasses. Multivariate data modeling (orthogonal projections to latent structures-discriminate analysis; OPLS-DA) revealed alterations in lipoprotein and lipid metabolism when comparing the baseline control to hospital admission samples, with the phenotypic signature found to be sustained at follow up. Univariate (Mann-Whitney U) testing and OPLS-DA indicated specific increases in GlycB (p-value < 1.0e-4), low density lipoprotein-2 subfractions (variable importance in projection score; VIP > 6.83e-1) and monoacyglyceride (20:4) (p-value < 1.0e-4) and decreases in circulating anti-inflammatory high-density lipoprotein-4 subfractions (VIP > 7.75e-1), phosphatidylcholines, phosphatidylglycerols, phosphatidylinositols, and phosphatidylserines. The results indicate a persistent systemic metabolic phenotype that occurs even in cases of a nonsevere burn injury. The phenotype is indicative of an acute inflammatory profile that continues to be sustained postinjury, suggesting an impact on systems health beyond the site of injury. The phenotypes contained metabolic signatures consistent with chronic inflammatory states reported to have an elevated incidence postburn injury. Such phenotypic signatures may provide patient stratification opportunities, to identify individual responses to injury, personalize intervention strategies, and improve acute care, reducing the risk of chronic comorbidity.

The epigenetics of keloids.

Keloid scarring is a fibroproliferative disorder of the skin with unknown pathophysiology, characterised by fibrotic tissue that extends beyond the boundaries of the original wound. Therapeutic options are few and commonly ineffective, with keloids very commonly recurring even after surgery and adjunct treatments. Epigenetics, defined as alterations to the DNA not involving the base-pair sequence, is a key regulator of cell functions, and aberrant epigenetic modifications have been found to contribute to many pathologies. Multiple studies have examined many different epigenetic modifications in keloids, including DNA methylation, histone modification, microRNAs and long non-coding RNAs. These studies have established that epigenetic dysregulation exists in keloid scars, and successful future treatment of keloids may involve reverting these aberrant modifications back to those found in normal skin. Here we summarise the clinical and experimental studies available on the epigenetics of keloids, discuss the major open questions and future perspectives on the treatment of this disease.

A review of epigenetic regulation in wound healing: Implications for the future of wound care.

Epigenetic regulatory mechanisms are essential for maintaining skin homeostasis and aid in the processes of wound healing. The nucleus co-ordinates gene expression using epigenetic regulatory mechanisms based on distinct chromatin structural states and their remodeling. These include DNA methylation and hydroxymethylation, post-translational histone modifications, ATP-dependent chromatin remodeling and higher-order chromatin structure and 3D genome organization. Epigenetic pathways play a key role in co-ordinating the behavior and activity of the multitude of cell types seen during skin repair, and research is now focusing on how wound healing can be modulated by altering the activity of certain reparative genes. Herein, we aim to highlight recent advances in understanding epigenetic regulatory mechanisms, with particular reference to those involved in keratinocyte and fibroblast biology. We also propose future directions for exploration of epigenetic mechanisms, and their potential clinical applications in acute wound care.

IFNß inhibits the development of allergen tolerance and is conducive to the development of asthma on subsequent allergen exposure.

Asthma is a chronic disease affecting up to 10% of the Australian population for which medical treatment is solely aimed at relief of symptoms rather than prevention of disease. Evidence from animal and human studies demonstrates a strong link between viral respiratory infections, atopy and the development of asthma. Type I IFNs include IFNα and IFNß, with subtype expression tailored toward the specific viral infection. We hypothesized that exposure to type I IFNs and allergen may interfere with the healthy response to innocuous airway antigen exposure. In this study, we use an ovalbumin (OVA)-induced BALB/c model of experimental allergic airways disease, where pre-exposure of the airways to OVA is protective against allergen sensitization, leading to allergen tolerance. We investigated airways pre-exposure with OVA and type I IFNs on development of allergic airways disease. We demonstrate restoration of allergic airways disease on pre-exposure with allergen and IFNß, and not IFNα. Dysfunction in tolerance led to changes in dendritic cell antigen capture/traffic, T-cell and B-cell responses. Furthermore, exposure to IFNß with ongoing allergen exposure led to the development of hallmark asthma features, including OVA-specific IgE and airways eosinophilia. Data indicate a role for IFNß in linking viral infection and allergy.

Verapamil is Less Effective than Triamcinolone for Prevention of Keloid Scar Recurrence After Excision in a Randomized Controlled Trial.

A double-blind randomized controlled trial with a paired split-scar design compared verapamil, an L-type Ca2+ channel antagonist, and triamcinolone for prevention of keloid recurrence after excision. Ca2+ channel blocking activity of verapamil in keloid cells was explored. One keloid was excised per subject and each wound half randomized to receive intralesional injections of triamcinolone (10 mg/ml) or verapamil (2.5 mg/ml) at monthly intervals (4 doses). Interim analysis was performed after 14 subjects were completed. Survival analysis demonstrated significantly higher keloid recurrence with verapamil compared to triamcinolone 12 months post-surgery (log-rank test, p = 0.01) and higher overall risk of recurrence with verapamil (hazard ratio 8.44, 95% CI 1.62-44.05). The study was terminated early according to the stopping guideline (p < 0.05). Verapamil is safe but not as effective as triamcinolone in preventing keloid recurrence after excision. Further study is necessary to determine if clinical response to verapamil is linked to modulation of intracellular Ca2+.

The Short- and Long-Term Outcome Priorities of a Western Australian Adult Burn Population.

To optimize patient recovery, understanding which outcomes are most important to burn patients is key. However, research to determine what outcomes are patient priorities is limited. Therefore, we assessed what outcomes are most important to Western Australian burn patients, separately in the short-term (<6 months) and long-term (6-24 months) after injury. Adult patients who had a burn injury 3-36 months ago completed a survey, rating the importance of 36 short- and long-term outcomes. The survey items were ranked according to the number of patients reporting the outcome as "very important." Results were compared between subgroups based on age, gender, burn size, and number of surgeries. Ninety-three patients were included. In the short-term, "not having a wound infection" (87.1%), "good wound healing" (83.9%), and "walking or moving around" (74.7%) were the most important outcomes. "Lifting or moving something" (67.6%), "walking or moving around" (66.2%), and "being independent" (66.2%) were reported as most important in the long-term. Scar-related outcomes were more important to females and to patients with multiple surgeries; mental health outcomes were priorities for females and patients with major burns; walking and moving around to males and older patients; and social and financial outcomes were rated highly by patients with major burns and multiple surgeries. In conclusion, the most important outcomes were consistent across time periods, indicating the importance of core outcomes in longitudinal follow-up. The wide range of priority outcomes and differences between subgroups underlines the need for multidisciplinary care and a patient-centered approach to support patients.

The impact of burn injury on the central nervous system.

Burn injuries can be devastating, with life-long impacts including an increased risk of hospitalization for a wide range of secondary morbidities. One area that remains not fully understood is the impact of burn trauma on the central nervous system (CNS). This review will outline the current findings on the physiological impact that burns have on the CNS and how this may contribute to the development of neural comorbidities including mental health conditions. This review highlights the damaging effects caused by burn injuries on the CNS, characterized by changes to metabolism, molecular damage to cells and their organelles, and disturbance to sensory, motor and cognitive functions in the CNS. This damage is likely initiated by the inflammatory response that accompanies burn injury, and it is often long-lasting. Treatments used to relieve the symptoms of damage to the CNS due to burn injury often target inflammatory pathways. However, there are non-invasive treatments for burn patients that target the functional and cognitive damage caused by the burn, including transcranial magnetic stimulation and virtual reality. Future research should focus on understanding the mechanisms that underpin the impact of a burn injury on the CNS, burn severity thresholds required to inflict damage to the CNS, and acute and long-term therapies to ameliorate deleterious CNS changes after a burn.

Non-severe burn injury causes sustained platelet hyperreactivity.

Individuals who present to a hospital for treatment of a burn of any magnitude are more frequently hospitalised for ischemic heart disease, even decades after injury. Blood platelets are key mediators of cardiovascular disease. To investigate platelet involvement in post-burn cardiovascular risk, platelet reactivity was assessed in patients at 2- and 6-weeks after non-severe (TBSA < 20%) burn injury, and in a murine model 30 days after 8% TBSA full-thickness burn injury. Platelets were stimulated with canonical agonists and function reported by GPIIb/IIIa PAC1-binding site, CD62P expression, and formation of monocyte-platelet aggregates. In vivo thrombosis in a modified Folts model of vascular injury was assessed. Burn survivors had elevated frequencies of circulating monocyte-platelet aggregates, and platelets were hyperreactive, primarily to collagen stimulation. Burn plasma did not cause hyper-reactivity when incubated with control platelets. Platelets from burn injured mice also demonstrated increased response to collagen peptides but did not show any change in thrombosis following vascular injury. This study demonstrates the persistence of a small but significant platelet hyperreactivity following burn injury. Although our data does not suggest this heightened platelet sensitivity modulates thrombosis following vascular injury, the contribution of sub-clinical platelet hyperreactivity to accelerating atherogenesis merits further investigation.

Functional Brain Changes Following Burn Injury: A Narrative Review.

BACKGROUND: Burn injuries cause significant motor and sensory dysfunctions that can negatively impact burn survivors' quality of life. The underlying mechanisms of these burn-induced dysfunctions have primarily been associated with damage to the peripheral neural architecture, however, evidence points to a systemic influence of burn injury. Central nervous system (CNS) reorganizations due to inflammation, afferent dysfunction, and pain could contribute to persistent motor and sensory dysfunction in burn survivors. Recent evidence shows that the capacity for neuroplasticity is associated with self-reported functional recovery in burn survivors. OBJECTIVE: This review first outlines motor and sensory dysfunctions following burn injury and critically examines recent literature investigating the mechanisms mediating CNS reorganization following burn injury. The review then provides recommendations for future research and interventions targeting the CNS such as non-invasive brain stimulation to improve functional recovery. CONCLUSIONS: Directing focus to the CNS following burn injury, alongside the development of non-invasive methods to induce functionally beneficial neuroplasticity in the CNS, could advance treatments and transform clinical practice to improve quality of life in burn survivors.

Unremitting pro-inflammatory T-cell phenotypes, and macrophage activity, following paediatric burn injury.

Objectives: The aim of this study was to characterise the dynamic immune profile of paediatric burn patients for up to 18 months post-burn. Methods: Flow cytometry was used to measure 25 cell markers, chemokines and cytokines which reflected both pro-inflammatory and anti-inflammatory immune profiles. Peripheral blood mononuclear cells from 6 paediatric burn patients who had returned for repeated burn and scar treatments for > 4 timepoints within 12 months post-burn were compared to four age-matched healthy controls. Results: While overall proportions of T cells, NK cells and macrophages remained relatively constant, over time percentages of these immune cells differentiated into effector and proinflammatory cell phenotypes including Th17 and activated γδ T cells. Circulating proportions of γδ T cells increased their expression of pro-inflammatory mediators throughout the burn recovery, with a 3-6 fold increase of IL-17 at 1-3 weeks, and NFκß 9-18 months post-burn. T-regulatory cell plasticity was also observed, and Treg phenotype proportions changed from systemically reduced skin-homing T-regs (CCR4+) and increased inflammatory (CCR6+) at 1-month post-burn, to double-positive cell types (CCR4+CCR6+) elevated in circulation for 18 months post-burn. Furthermore, Tregs were observed to proportionally express less IL-10 but increased TNF-α over 18 months. Conclusion: Overall, these results indicate the circulating percentages of immune cells do not increase or decrease over time post-burn, instead they become highly specialised, inflammatory and skin-homing. In this patient population, these changes persisted for at least 18 months post-burn, this 'immune distraction' may limit the ability of immune cells to prioritise other threats post-burn, such as respiratory infections.

Inflammatory proteins and neutrophil extracellular traps increase in burn blister fluid 24h after burn.

Burn wound blister fluid is a valuable matrix for understanding the biological pathways associated with burn injury. In this study, 152 blister fluid samples collected from paediatric burn wounds at three different hospitals were analysed using mass spectrometry proteomic techniques. The protein abundance profile at different days after burn indicated more proteins were associated with cellular damage/repair in the first 24 h, whereas after this point more proteins were associated with antimicrobial defence. The inflammatory proteins persisted at a high level in the blister fluid for more than 7 days. This may indicate that removal of burn blisters prior to two days after burn is optimal to prevent excessive or prolonged inflammation in the wound environment. Additionally, many proteins associated with the neutrophil extracellular trap (NET) pathway were increased after burn, further implicating NETs in the post-burn inflammatory response. NET inhibitors may therefore be a potential treatment to reduce post-burn inflammation and coagulation pathology and enhance burn wound healing outcomes.

Genetic influence on scar vascularity after burn injury in individuals of European ancestry: A prospective cohort study.

After burn injury there is considerable variation in scar outcome, partially due to genetic factors. Scar vascularity is one characteristic that varies between individuals, and this study aimed to identify genetic variants contributing to different scar vascularity outcomes. An exome-wide array association study and gene pathway analysis was performed on a prospective cohort of 665 patients of European ancestry treated for burn injury, using their scar vascularity (SV) sub-score, part of the modified Vancouver Scar Scale (mVSS), as an outcome measure. DNA was genotyped using the Infinium HumanCoreExome-24 BeadChip, imputed to the Haplotype Reference Consortium panel. Associations between genetic variants (single nucleotide polymorphisms) and SV were estimated using an additive genetic model adjusting for sex, age, % total body surface area and number of surgical procedures, utilising linear and multinomial logistic regression. No individual genetic variants achieved the cut-off threshold for significance. Gene sets were also analysed using the Functional Mapping and Annotation (FUMA) platform, in which biological processes indirectly related to angiogenesis were significantly represented. This study suggests that SNPs in genes associated with angiogenesis may influence SV, but further studies with larger datasets are essential to validate these findings.

Non-severe thermal burn injuries induce long-lasting downregulation of gene expression in cortical excitatory neurons and microglia.

Burn injuries are devastating traumas, often leading to life-long consequences that extend beyond the observable burn scar. In the context of the nervous system, burn injury patients commonly develop chronic neurological disorders and have been suggested to have impaired motor cortex function, but the long-lasting impact on neurons and glia in the brain is unknown. Using a mouse model of non-severe burn injury, excitatory and inhibitory neurons in the primary motor cortex were labelled with fluorescent proteins using adeno-associated viruses (AAVs). A total of 5 weeks following the burn injury, virus labelled excitatory and inhibitory neurons were isolated using fluorescence-activated cell sorting (FACS). In addition, microglia and astrocytes from the remaining cortical tissue caudal to the motor cortex were immunolabelled and isolated with FACS. Whole transcriptome RNA-sequencing was used to identify any long-lasting changes to gene expression in the different cell types. RNA-seq analysis showed changes to the expression of a small number of genes with known functions in excitatory neurons and microglia, but not in inhibitory neurons or astrocytes. Specifically, genes related to GABA-A receptors in excitatory neurons and several cellular functions in microglia were found to be downregulated in burn injured mice. These findings suggest that non-severe burn injuries lead to long lasting transcriptomic changes in the brain, but only in specific cell types. Our findings provide a broad overview of the long-lasting impact of burn injuries on the central nervous system which may help identify potential therapeutic targets to prevent neurological dysfunction in burn patients.

Quality of life in paediatric burn patients with non-severe burns.

BACKGROUND: Burns are common worldwide, and the vast majority are non-severe burns of less than 20% of the total body surface area (TBSA). In Australia, paediatric burns account for a third of all burn admissions, thus understanding the quality-of-life outcomes after a non-severe burn in children is important. METHODS: This retrospective cohort study describes a paediatric cohort from Western Australia with non-severe burns occurring between 2018 and 2020 and characterises the child's quality-of-life outcomes which is measured using the Paediatric quality of life survey (PedsQL). The PedsQL included a parent-report and child-report assessment, each with a physical function domain and a psychosocial function domain which comprised of an emotional, a social and a school category. RESULTS: Data collected from 249 patients; 50.6% were male, 45.6% were toddlers. The most common cause was scald (48.19%), the majority had burns smaller than 5% TBSA (91.97%), and most included visible areas such as head, neck or hands (77.51%). The parent-report PedsQL scores were significantly different for both physical and psychosocial domains between the different age groups (p = 0.002, p = 0.001, respectively) and for burn cause (p = 0.004, p = 0.005, respectively). For child-reported scores we found evidence of an effect of burn cause across both domains that did not reach a statistical significance (p = 0.076, p = 0.078, respectively). The psychosocial functions in both the parent-report and the self-report were significantly different for the socioeconomic status groups (p = 0.015, p = 0.032, respectively). Quality of life scores were critically low in 16.46% of paediatric burn patients at three months after burn. CONCLUSION: Parent-reported and child-reported psychosocial function was significantly poorer in higher socioeconomic groups, for older children and for those with flame burns. About 16% of patients had scores below the critical cut off. These data provide insight into the quality-of-life outcomes of paediatric patients with non-severe burns, allowing future studies to investigate burn prevention strategies and services to help paediatric burn patients in their recovery.

A comparison of parent-reported and self-reported psychosocial function scores of the PedsQL for children with non-severe burn.

BACKGROUND: Quality of life of paediatric patients after burn injury is often assessed through parents who may score differently to their child. Non-severe burns are the most common type of burn injury in Western Australia, however, despite low severity and high survival rates, they can cause long term physical and psychosocial problems which need to be detected early in order to provide patients with optimal holistic care. METHODS: Demographic and clinical data were collected from paediatric patients (5-16-year-old) with non-severe burns (<20% total body surface area), and Paediatric quality of life (PedsQL) questionnaires were collected from both the patient and their parent. Two cohorts of patients were assessed: first, those at approximately six months after burn, and second, those more than one-year after burn. Differences between parent-scores and self-scores were analysed using multivariate linear regression to assess the relationship between risk factors and observed differences in PedsQL scores. RESULTS: Parents reported poorer Psychosocial Function (PSF) for younger children (p = 0.01) and for patients from higher socioeconomic status areas (p = 0.05) compared to their children. In the 'Early Recovery Cohort', female patients had significantly different scores to their parents (p < 0.01). In the 'Late Recovery Cohort', parents rated older patients lower than they rated themselves (p = 0.03). CONCLUSION: Age at burn, socioeconomic status, and female gender may increase the discrepancy in quality-of-life assessments between parents and patients.

Carbon dioxide laser treatment of burn-related scarring: Results of the ELIPSE (Early Laser Intervention Promotes Scar Evolution) prospective randomized controlled trial.

AIM: To investigate the impact of ablative fractional carbon dioxide laser (AFCO2L) on patient-reported outcomes measures, subjective scar appearance, dermal architecture, and gene transcription in early burn scars. METHODS: Fifteen adult patients with a burn-related scar were recruited. Inclusion criteria were two non-contiguous scar areas of 1% total body surface area, similar baseline Vancouver scar scale (VSS) score and 3months since the time of injury. All participants acted as their own control. Scars were randomized to treatment or control. Treatment scars received three AFCO2L treatments at 6-week intervals. Outcome measures were recorded at baseline, 3, 6, and 12-months post-treatment. Measures included blinded VSS, Patient Observer Scar Assessment Scale (POSAS), Brisbane Burn Scar Impact Profile (BBSIP), blinded scar photo assessment, histological tissue analysis, and RNA sequencing analysis. RESULTS: No significant difference was found in VSS, scar erythema, or pigmentation. Patient POSAS improved in scar thickness and texture following AFCO2L. All elements of BBSIP improved in control and laser groups. AFCO2L-treated scars were scored better than control scars by blinded raters. RNA sequencing illustrated that AFCO2L induced sustained changes in fibroblast gene expression. CONCLUSIONS: AFCO2L treated scars had significantly altered scar thickness and texture 6 months post-laser and were rated better than controls on blinded photo analysis after 3 treatments. RNASeq results suggest laser treatment alters the transcriptome of treated fibroblasts for at least 3 months after treatment. Expansion of this research to study in more depth fibroblast changes in response to laser, as well as assessing the impact on daily activity and quality of life, will be beneficial.

Plasma lipidomics reveal systemic changes persistent throughout early life following a childhood burn injury.

Background: Non-severe paediatric burns can result in poor long-term health outcomes. This occurs even in cases with good acute burn-related outcomes, including minimal scarring. The mechanisms that underpin the transition from non-severe burn to sustained negative long-term health impacts are currently unknown. However, sustained metabolic and immune changes have been observed in paediatric burn studies, suggesting these changes may be important.The plasma lipidome consists of a rich pool of bioactive metabolites that play critical roles in systemic processes including molecular signalling and inflammation. We hypothesised that changes in the plasma lipidome may reflect underlying changes in health status and be linked to long-term health after burn trauma. Methods: This study analysed the lipidome in children who had previously experienced a non-severe burn, compared to non-injured controls. Thirty-three participants were recruited between the ages of 5 and 8 years who had experienced a non-severe burn between the ages of 1 and 3 years. Plasma samples were also collected from a non-injured, healthy, age and gender matched control group (n = 21). Plasma lipids were measured using reversed-phase liquid chromatographymass spectrometery (LC-MS). Results: In total 838 reproducible lipid species from 19 sub-classes passed quality control procedures and progressed to statistical analysis. Analysis of individual lipid metabolites showed significantly higher concentrations of lysophosphatidylethanolamines and phosphatidylethanolamines, and significantly lower concentrations in myristic, palmitic and palmitoleic acids in the plasma of those who had experienced burn injury compared to controls. Conclusion: Long-term changes in the lipid profile may give insight into the mechanisms underlying poor long-term health subsequent to non-severe burn injury. Further work to investigate the relationship between long-term pathology and lipidomic changes may lead to a better understanding of the causes of secondary morbidity post-burn and to clinical intervention to reduce the long-term health burden of burn trauma.

Higher operating theatre temperature during burn surgery increases physiological heat strain, subjective workload, and fatigue of surgical staff.

Raising the ambient temperature of the operating theatre is common practice during burn surgeries to maintain the patient's core body temperature; however, the effects of operating in the heat on cognitive performance, manual dexterity, and perceived workload of surgical staff have not been assessed in a real-world context. Therefore, the aim was to assess the real-time impact of heat during burn surgeries on staff's cognitive function, manual dexterity, and perceptual measures (workload, thermal sensation, thermal comfort, perceived exertion, and fatigue) and physiological parameters (core temperature, heart-rate, fluid loss, and dehydration). Ten burn surgery staff members were assessed in CON (24.0±1.1°C, 45±6% relative humidity [RH]) and HOT (30.8±1.6°C, 39±7% RH) burn surgeries (average 150 min duration). Cognitive performance, manual dexterity, and perceptual measures were recorded pre- and post-surgery, while physiological parameters were recorded throughout surgery. HOT conditions did not significantly affect manual dexterity or cognitive function (p > .05), however HOT resulted in heat strain (increased heart-rate, core temperature, and fluid loss: p < .05), and increased subjective workload, discomfort, perceived exertion, and fatigue compared to CON conditions (p < .05). Cognitive function and manual dexterity were maintained in hot conditions, suggesting that operating in approximately 31°C heat is a safe approach for patient treatment. However, job burnout, which is positively correlated with perceived workload, and the impact of cumulative fatigue on the mental health of surgery staff, must be considered in the context of supporting an effective health workforce.

Cardiometabolic disease risk markers are increased following burn injury in children.

Introduction: Burn injury in children causes prolonged systemic effects on physiology and metabolism leading to increased morbidity and mortality, yet much remains undefined regarding the metabolic trajectory towards specific health outcomes. Methods: A multi-platform strategy was implemented to evaluate the long-term immuno-metabolic consequences of burn injury combining metabolite, lipoprotein, and cytokine panels. Plasma samples from 36 children aged 4-8 years were collected 3 years after a burn injury together with 21 samples from non-injured age and sex matched controls. Three different 1H Nuclear Magnetic Resonance spectroscopic experiments were applied to capture information on plasma low molecular weight metabolites, lipoproteins, and α-1-acid glycoprotein. Results: Burn injury was characterized by underlying signatures of hyperglycaemia, hypermetabolism and inflammation, suggesting disruption of multiple pathways relating to glycolysis, tricarboxylic acid cycle, amino acid metabolism and the urea cycle. In addition, very low-density lipoprotein sub-components were significantly reduced in participants with burn injury whereas small-dense low density lipoprotein particles were significantly elevated in the burn injured patient plasma compared to uninjured controls, potentially indicative of modified cardiometabolic risk after a burn. Weighted-node Metabolite Correlation Network Analysis was restricted to the significantly differential features (q <0.05) between the children with and without burn injury and demonstrated a striking disparity in the number of statistical correlations between cytokines, lipoproteins, and small molecular metabolites in the injured groups, with increased correlations between these groups. Discussion: These findings suggest a 'metabolic memory' of burn defined by a signature of interlinked and perturbed immune and metabolic function. Burn injury is associated with a series of adverse metabolic changes that persist chronically and are independent of burn severity and this study demonstrates increased risk of cardiovascular disease in the long-term. These findings highlight a crucial need for improved longer term monitoring of cardiometabolic health in a vulnerable population of children that have undergone burn injury.