Stratification of Sepsis Patients on Admission into the Intensive Care Unit According to Differential Plasma Metabolic Phenotypes.

Delayed diagnosis of patients with sepsis or septic shock is associated with increased mortality and morbidity. UPLC-MS and NMR spectroscopy were used to measure panels of lipoproteins, lipids, biogenic amines, amino acids, and tryptophan pathway metabolites in blood plasma samples collected from 152 patients within 48 h of admission into the Intensive Care Unit (ICU) where 62 patients had no sepsis, 71 patients had sepsis, and 19 patients had septic shock. Patients with sepsis or septic shock had higher concentrations of neopterin and lower levels of HDL cholesterol and phospholipid particles in comparison to nonsepsis patients. Septic shock could be differentiated from sepsis patients based on different concentrations of 10 lipids, including significantly lower concentrations of five phosphatidylcholine species, three cholesterol esters, one dihydroceramide, and one phosphatidylethanolamine. The Supramolecular Phospholipid Composite (SPC) was reduced in all ICU patients, while the composite markers of acute phase glycoproteins were increased in the sepsis and septic shock patients within 48 h admission into ICU. We show that the plasma metabolic phenotype obtained within 48 h of ICU admission is diagnostic for the presence of sepsis and that septic shock can be differentiated from sepsis based on the lipid profile.

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.

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.

Plasma cell but not CD20-mediated B-cell depletion protects from bleomycin-induced lung fibrosis.

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease associated with chronic inflammation and tissue remodelling leading to fibrosis, reduced pulmonary function, respiratory failure and death. Bleomycin (Blm)-induced lung fibrosis in mice replicates several clinical features of human IPF, including prominent lymphoid aggregates of predominantly B-cells that accumulate in the lung adjacent to areas of active fibrosis. We have shown previously a requirement for B-cells in the development of Blm-induced lung fibrosis in mice. To determine the therapeutic potential of inhibiting B-cell function in pulmonary fibrosis, we examined the effects of anti-CD20 B-cell ablation therapy to selectively remove mature B-cells from the immune system and inhibit Blm-induced lung fibrosis. Anti-CD20 B-cell ablation did not reduce fibrosis in this model; however, immune phenotyping of peripheral blood and lung resident cells revealed that anti-CD20-treated mice retained a high frequency of CD19+ CD138+ plasma cells. Interestingly, high levels of CD138+ cells were also identified in the lung tissue of patients with IPF, consistent with the mouse model. Treatment of mice with bortezomib, which depletes plasma cells, reduced the level of Blm-induced lung fibrosis, implicating plasma cells as important effector cells in the development and progression of pulmonary fibrosis.

Sampling the skin surface chemistry for diagnosis and prognosis.

Skin and wound blotting are non-invasive techniques used to sample the skin and wound surface chemistry, whereby a nitrocellulose membrane is applied to an intact or broken cutaneous surface to detect biomarkers. However, there has been no comprehensive review of the evidence for the techniques used and data obtained to date. The primary aim of this study was to review the utilities of surface blotting for the diagnosis and prognosis of physiological, pre-disease, and pathological states. The secondary aim was to summarise the procedural steps. A systematic literature search was conducted on 9 July 2021 using Medline, Embase, and Google Scholar databases. Investigators used McMaster's Critical Review Form for Quantitative Studies to assess quality, then performed a narrative synthesis reporting according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Twenty-five studies were reviewed. Eighteen studies were of good quality, and seven were of moderate quality. These studies conducted skin and wound blotting on 176 animals and 1546 humans. Studies reported physiological and pathological states for diagnosis and prediction of conditions, including skin tears, wound healing, biofilm detection, and skin barrier function. The four steps for blotting are surface preparation, blot preparation, application and removal of blot, and analysis. This review demonstrates that blotting can determine the skin and wound surface chemistry using a versatile and reproducible technique. However, future research is needed to validate the technique and skin biomarkers identified.

Local burn wound environment versus systemic response: Comparison of proteins and metabolites.

In this study, paired blood plasma (BP) and blister fluid (BF) samples from five paediatric burn patients were analysed using mass spectrometry to compare their protein and metabolite composition. The relative quantification of proteins was achieved through a label-free data independent acquisition mode. The relative quantification of metabolites was achieved using a Shimadzu Smart Metabolite Database gas chromatography mass spectrometry (GCMS) targeted assay. In total, 562 proteins and 141 individual metabolites were identified in the samples. There was 81% similarity in the proteins present in the BP and BF, with 50 and 54 unique proteins found in each sample type respectively. BF contained keratinocyte proliferation-related proteins and blood plasma contained abundant blood clotting proteins and apolipoproteins. BF contained more carbohydrates and less alpha-hydroxy acid metabolites than the BP. In this study, there were unique proteins and metabolites in BF and BP which were reflective of the local wound environment and systemic environments respectively. The results from this study demonstrate that the biomolecule content of BF is mostly the same as blood, but it also contains information specific to the local wound environment.

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.

Effectiveness and efficiency of training in digital healthcare packages: training doctors to use digital medical record keeping software.

Objective Fiona Stanley Hospital (FSH) is the first hospital in Western Australia to implement a digital medical record (BOSSnet, Core Medical Solutions, Australia). Formal training in the use of the digital medical record is provided to all staff as part of the induction program. The aim of the present study was to evaluate whether the current training program facilitates efficient and accurate use of the digital medical record in clinical practice. Methods Participants were selected from the cohort of junior doctors employed at FSH in 2015. An e-Learning package of clinically relevant tasks from the digital medical record was created and, along with a questionnaire, completed by participants on two separate occasions. The time taken to complete all tasks and the number of incorrect mouse clicks used to complete each task were recorded and used as measures of efficiency and accuracy respectively. Results Most participants used BOSSnet more than 10 times per day in their clinical roles and self-rated their baseline overall computer proficiency level as high. There was a significant increase in the self-rating of proficiency levels in successive tests. In addition, a significant improvement in both efficiency and accuracy for all participants was measured between the two tests. Interestingly, both groups ended up with similar accuracy on the second trial, despite the second group of participants starting with significantly poorer accuracy. Conclusions Overall, the greatest improvements in task performance followed daily ward-based experience using BOSSnet rather than formalised training. The greatest benefits of training were noted when training was delivered in close proximity to the onset of employment. What is known about the topic? Formalised training in the use of information and communications technology (ICT) is widespread in the health service. However, there is limited evidence to support the modes of learning typically used. Formalised training is often costly and there is little other than anecdotal evidence that currently supports its efficacy in the workplace. What does the paper add? Assessment of accuracy when using the BOSSnet system over time revealed that daily use rather than formalised training appeared to have the most impact on performance. Formalised training was rated poorly, and this appeared to correlate with time between training and use. The present study suggests that formalised training, if required, should be delivered close in time to actual use of the system to benefit end-users. The study also shows that daily experience is more effective than formalised training to improve accuracy. What are the implications for practitioners? Formalised training for ICT needs to be scheduled in close proximity to end-user use of the ICT. Current scheduling may be beneficial for ease of delivery, but unless it is delivered at a suitable time the benefits are minimal. Formalised training programs may not be critical for all staff and all staff improve with contextualised experience given time. Training may be better suited to optional rather than compulsory delivery programs with ongoing delivery to suit user schedules.

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.

Evaluation of the accuracy of diagnostic coding and clinical documentation for traumatic heterotopic ossification diagnoses in Western Australian hospitals.

BACKGROUND: Traumatic heterotopic ossification (tHO) refers to the pathological formation of ectopic bone in soft tissues that can occur following burn, neurological ororthopaedic trauma. As completeness and accuracy of medical diagnostic coding can vary based on coding practices and depend on the institutional culture of clinical documentation, it is important to assess diagnostic coding in that local context. To the authors' knowledge, there is no prior study evaluating the accuracy of medical diagnostic coding or specificity of clinical documentation for tHO diagnoses across Western Australia (WA) trauma centres or across the full range of inciting injury and surgical events. OBJECTIVE: To evaluate and compare the clinical documentation and the diagnostic accuracy of ICD-10-AM coding for tHO in trauma populations across 4 WA hospitals. METHODS: A retrospective data search of the WA trauma database was conducted to identify patients with tHO admitted to WA hospitals following burn, neurological or orthopaedic trauma. Patient demographic and tHO diagnostic characteristics were assessed for all inpatient and outpatient tHO diagnoses. The frequency and distribution of M61 (HO-specific) and broader, musculoskeletal (non-specific) ICD-10-AM codes were evaluated for tHO cases in each trauma population. RESULTS: HO-specific M61 ICD-10-AM codes failed to identify more than a third of true tHO cases, with a high prevalence of non-specific HO codes (19.4 %) and cases identified via manual chart review (25.4 %). The sensitivity of M61 codes for correctly diagnosing tHO after burn injury was 50 %. ROC analysis showed that M61 ICD-10-AM codes as a predictor of a true positive tHO diagnosis were a less than favourable method (AUC=0.731, 95 % CI=0.561-0.902, p = 0.012). Marked variability in clinical documentation for tHO was identified across the hospital network. CONCLUSION: Coding inaccuracies may, in part, be influenced by insufficiencies in clinical documentation for tHO diagnoses, which may have implications for future research and patient care. Clinicians should consistently employ standardised clinical terminology from the point of care to increase the likelihood of accurate medical diagnostic coding for tHO diagnoses.

Trauma patient heterotopic ossification diagnosis is associated with increased hospital length of stay.

BACKGROUND: Traumatic heterotopic ossification (tHO) refers to the development of extra-skeletal bone in muscle and soft tissues following tissue insult secondary to surgery or trauma. This presents a persistent clinical concern associated with significant patient morbidity and expense to diagnose and treat. Traumatic HO is a substantial barrier to rehabilitation for trauma-injured patients. As such, the development of tHO after burn and other trauma is hypothesised to prolong inpatient length of stay (LOS) and thus increase health care costs. OBJECTIVE: To investigate the association between an inpatient tHO diagnosis and hospital LOS in trauma patients. METHODS: A retrospective audit of trauma patients over a 14-year period was completed using data from four WA hospitals. Burn and neurological trauma patients diagnosed with tHO as an inpatient (tHO+) and control subjects (tHO-), matched (1:3) by age, gender, and injury severity factors, were identified using medical diagnostic codes. Data relating to patient and injury-related determinants of LOS from tHO+ and tHO- subjects were analysed to model the association of tHO on total hospital length of stay. RESULTS: 188 identified patients were hospitalised due to traumatic injury; 47 patients with tHO following burn injury (n = 17), spinal cord injury (n = 13) and traumatic brain injury (n = 17), and 141 control patients. Those who developed tHO during hospitalisation had a significantly higher median LOS than matched trauma patients who did not develop tHO (142 days vs. 61 days). Multivariate regression analyses identified the following independent predictive factors of a prolonged hospital LOS: tHO diagnosis, mechanical ventilation hours, injury to the hip region and thigh area, other ossification disorder, pressure injury, admission to intensive care unit and deep vein thrombosis. Trauma patients diagnosed with tHO during their hospital admission stayed 1.6 times longer than trauma patients matched for injury severity without a tHO diagnosis (IRR 1.56, 95% CI 1.35-1.79, p<0.001). CONCLUSION: Traumatic heterotopic ossification is an independent explanatory factor for increased hospital LOS in patients following burns, spinal cord, and traumatic brain injury. Early diagnosis may assist in reducing the impact of tHO on acute hospital stay after trauma.

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.

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.

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.

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.