Cytokine expression profile over time in severely burned pediatric patients

Monocyte Anisocytosis Changes in Patients After Major Burn Injuries

The recovery of patients after severe burns is a long and complex process. Genomic analysis of white blood cells from burn and trauma patients revealed excessive and prolonged innate immune activation in patients with complicated outcomes. However, translating this knowledge into practical biomarkers has not been possible yet. Although several biomarkers for monitoring burn patients have been proposed, their ability to accurately distinguish between inflammation stemming from initial tissue destruction, infections, and organ failure complications is limited. Here, we focused on monocytes, critical innate immune cells in the response to burn injured tissues. We measured the monocyte anisocytosis (quantified as monocyte distribution width (MDW), a recently emerged marker of sepsis) throughout the recovery of patients from the time of burn injury until the end of the hospital stay. We observed that MDW increases in patients during the first week after major burns. Among the patients with major burns who survive, MDW starts decreasing in the second week and normalizes by the end of the hospital stay. The duration of hospital stay appears to be proportional to how fast MDW decreases during the second week after the injury. We also found that MDW decreases significantly in most patients after excision and debridement surgeries but not after allo- and auto-graft surgeries. Moreover, high MDW values correlated with a higher rate of positive microbiology blood culture samples and respiratory infections. These findings underscore the importance of monitoring MDW as a potential biomarker for the risk of complications during burn patient recovery.

Post-burns persistent inflammation leads to kidney PANoptosis with Caspases pathway activation

Background

There is higher prevalence of chronic kidney disease (CKD) in burn patients after hospital discharge; however, the cause remains unclear. This study aimed to investigate the lasting impacts of severe burns on the kidneys and to explore potential treatments.

Methods

The study examined the effects of burning on healthy mice and adenine-induced CKD mice. Subsequently, the investigation focused on assessing the effects of activated macrophages on podocytes. Finally, the study evaluated the effectiveness of dexamethasone in mitigating the impacts of burns on the kidneys.

Results

In healthy mice, burns caused only subclinical signs in the kidneys. However, in the CKD group, burns not only reduced kidney function, but also aggravated kidney injuries, apoptosis, and inflammation. Moreover, the expression of Caspase-1 and -3 signalings was significantly increased in all mice after burns. Electron microscopy revealed that burns exacerbated glomerular injury in the CKD group, including podocyte injury, cell membrane blebbing, and rupture. Furthermore, polarized M1 macrophages led to increased MPC5 podocyte death. Following dexamethasone intervention, kidney function and injuries were alleviated in CKD mice.

Conclusions

Severe burns can trigger PANoptosis by activating inflammation-induced Caspase-dependent pathways, which can lead to kidney injury in mice. This impairment is exacerbated in the CKD group. However, the administration of dexamethasone can effectively ameliorate kidney injury. These findings have significant implications for predicting the prognosis of kidney function in burn patients and offer a potential therapeutic approach.

Enrichment of H3S28p and H3K9me2 Epigenetic Marks on Inflammatory-Associated Gene Promoters in Response to Severe Burn Injury

BACKGROUND

Severe burns activate systemic inflammation and lead to an increase in cytokine levels. Epigenetic elements are key regulators of inflammation; however, their involvement in severe burns has not been studied. In this work, we aimed to unveil the histone H3 posttranslational modifications (PTM) profile and their enrichment in promoters of inflammatory genes in response to severe burns.

METHODS

The levels of H3 PTMs were analyzed by ELISA assays in circulating cells from burn patients. ChIP assays were conducted to evaluate the enrichment of H3K9me2 and H3S28p at the promoter of CXCL8, IL-17, TNFA, IL-6, FOS, and IL-1B genes.

RESULTS

We found that eight H3 PTMs decreased at 5 days post-burn. Burn patients showed a decreased enrichment of H3K9me2 in CXCL8, IL-17, and TNFA promoters, whereas IL-6, FOS, and IL-1B promoters displayed an H3S28p enrichment diminution during the first 10 days post-burn. Interestingly, burn-injured septic patients exhibited an increased enrichment of H3K9me2 in TNFA, IL-1B, CXCL8, and IL-17 promoters, whereas H3S28p was increased in promoters of TNFA and IL-1B at 1 dpb.

CONCLUSION

Severe burns trigger epigenetic changes and differential H3 PTM enrichment at inflammation gene promoters. Epigenetic misregulation of H3 may be involved in sepsis occurrence after severe burn injury.

FAS(APO), DAMP, and AKT Phosphoproteins Expression Predict the Development of Nosocomial Infection After Pediatric Burn Injury

Pediatric burn injuries are a leading cause of morbidity with infections being the most common acute complication. Thermal injuries elicit a heightened cytokine response while suppressing immune function; however, the mechanisms leading to this dysfunction are still unknown. Our aim was to identify extracellular proteins and circulating phosphoprotein expression in the plasma after burn injury to predict the development of nosocomial infection (NI). Plasma was collected within 72 hours after injury from 64 pediatric burn subjects; of these, 18 went on to develop an NI. Extracellular damage-associated molecular proteins, FAS(APO), and protein kinase b (AKT) signaling phosphoproteins were analyzed. Subjects who went on to develop an NI had elevated high-mobility group box 1, heat shock protein 90 (HSP90), and FAS expression than those who did not develop an NI after injury (NoNI). Concurrently, phosphorylated (p-)AKT and mammalian target of rapamycin (p-mTOR) were elevated in those subjects who went on to develop an NI. Quadratic discriminant analysis revealed distinct differential profiles between NI and NoNI burn subjects using HSP90, FAS, and p-mTOR. The area under the receiver-operator characteristic curves displayed significant ability to distinguish between these 2 burn subject cohorts. These findings provide insight into predicting the signaling proteins involved in the development of NI in pediatric burn patients. Further, these proteins show promise as a diagnostic tool for pediatric burn patients at risk of developing infection while additional investigation may lead to potential therapeutics to prevent NI.

Understanding innate and adaptive responses during radiation combined burn injuries

The occurrence of incidents involving radiation-combined burn injuries (RCBI) poses a significant risk to public health. Understanding the immunological and physiological responses associated with such injuries is crucial for developing care triage to counter the mortality that occurs due to the synergistic effects of radiation and burn injuries. The core focus of this narrative review lies in unraveling the immune response against RCBI. Langerhans cells, mast cells, keratinocytes, and fibroblasts, which induce innate immunity, have been explored for their response to radiation, burns, and combined injuries. In the case of adaptive immune response, exploring behavioral changes in T regulatory (Treg) cells, T helper cells (Th1, Th2, and Th17), and immunoglobulin results in delayed healing compared to burn and radiation injury. The review also includes the function of complement system components such as neutrophils, acute phase proteins (CRP, C3, and C5), and cytokines for their role in RCBI. Combined insults resulting in a reduction in the cell population of immune cells display variation in response based on radiation doses, burn injury types, and their intrinsic radiosensitivity. The lack of approved countermeasures against RCBI poses a significant challenge. Drug repurposing might help to balance immune cell alteration, resulting in fast recovery and decreasing mortality, which gives it clinical significance for its implication on the site of such incidence. However, the exact immune response in RCBI remains insufficiently explored in pre-clinical and clinical stages, which might be due to the non-availability of in vitro models, standard animal models, or human subjects, warranting further research.

New-onset autoantibodies to selenoprotein P following severe burn injury

The liver-derived selenium (Se) transporter selenoprotein P (SELENOP) declines in critical illness as a negative acute phase reactant and has recently been identified as an autoantigen. Hepatic selenoprotein biosynthesis and cotranslational selenocysteine insertion are sensitive to inflammation, therapeutic drugs, Se deficiency, and other modifiers. As severe burn injury induces a heavy inflammatory burden with concomitant Se depletion, we hypothesized an impairment of selenoprotein biosynthesis in the acute post-burn phase, potentially triggering the development of autoantibodies to SELENOP (SELENOP-aAb). To test this hypothesis, longitudinal serum samples from severely burned patients were analyzed over a period of six months. Newly occurring SELENOP-aAb were detected in 8.4% (7/83) of the burn patients, with onset not earlier than two weeks after injury. Prevalence of SELENOP-aAb was associated with injury severity, as aAb-positive patients have suffered more severe burns than their aAb-negative counterparts (median [IQR] ABSI: 11 [7-12] vs. 7 [5.8-8], p = 0.023). Autoimmunity to SELENOP was not associated with differences in total serum Se or SELENOP concentrations. A positive correlation of kidney-derived glutathione peroxidase (GPx3) with serum SELENOP was not present in the patients with SELENOP-aAb, who showed delayed normalization of GPx3 activity post-burn. Overall, the data suggest that SELENOP-aAb emerge after severe injury in a subset of patients and have antagonistic effects on Se transport. The nature of burn injury as a sudden event allowed a time-resolved analysis of a direct trigger for new-onset SELENOP-aAb, which may be relevant for severely affected patients requiring intensified acute and long-term care.

Severity and Clinical Outcomes of Pediatric Burns-A Comprehensive Analysis of Influencing Factors

(1) Background: Burn injuries in children present a significant public health concern due to their potential for severe physical and psychological impact. (2) Methods: This study investigates the determinants of pediatric burn severity by analyzing the interplay of demographic and environmental factors. Through a retrospective analysis of pediatric burn cases over five years, encompassing patient demographics, burn causative agents, and clinical outcomes, this research aims to identify significant predictors of burn severity. (3) Results: This study presents a comprehensive analysis of pediatric burn injuries, focusing on the severity, clinical outcomes, and multifactorial aspects influencing recovery. We reviewed 1498 pediatric burn cases from January 2015 to December 2020. The mean age of patients was 5.8 years, with a slight male predominance (54%). Scalds (45%), flame burns (30%), and contact burns (15%) were the most common burn types. Our findings indicate significant differences in burn severity based on TBSA, with 32.5% of cases having TBSA greater than 20%. Multivariate logistic regression identified rural residence, male gender, flame burns, and lower socioeconomic status as significant predictors of severe burn outcomes. The overall mortality rate was 2.5%, with higher rates among patients with TBSA greater than 40%. These results highlight the need for targeted prevention strategies and improved access to specialized burn care. (4) Conclusions: Understanding these factors can inform targeted prevention strategies and improve treatment protocols.

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.

Ninety Sixth-Hour Impact of Scalding Burns on End Organ Damage, Systemic Oxidative Stress, and Wound Healing in Rats Treated With Three Different Types of Dressings

In this study, we investigated the effects of 3 different burn dressing treatments, including experimental, silver, and modern dressing materials, on systemic oxidative stress in rats with severe scald burns within the first 96 h. The rats were divided into five groups: a burn group (n = 10), a polylactic membrane group (n = 10), a silver sulfadiazine group (n = 10), a curcumin group (n = 10), and a control group (n = 10), consisting of equal numbers of female and male rats. In the first 4 groups, 30% of the rats' total body surface area was scalded at 95°C. The burn group was not treated. Each group was treated with group-name dressing material. The control group was neither treated nor burned. The rats were sacrificed, and blood and tissue samples were obtained at the 96th hour when severe effects of oxidative stress developed postburns. Systemic inflammatory biomarkers and oxidative stress parameters were examined. In addition, apoptosis and organ damage in liver, kidney, lung, and skin tissues were evaluated biochemically and histopathologically. When the parameters were statistically analyzed, we found that the systemic levels of oxidative stress and inflammatory damage to liver, kidney, and lung tissues were lower in the 3 treated groups than in the burn group. We believe that the dressing material's efficacy in the treatment of severe burns may be dependent on its ability to combat oxidative stress and inflammation.

Challenges in the Management of Large Burns

Large burns provoke profound pathophysiological changes. Survival rates of patients with large burns have improved significantly with the advancement of critical care and adaptation of early excision protocols. Nevertheless, care of large burn wounds remains challenging secondary to limited donor sites, prolonged time to wound closure, and immunosuppression. The development of skin substitutes and new grafting techniques decreased time to wound closure. Individually, these methods have limited success, but a combination of them may yield more successful outcomes. Early identification of patients with likely poor prognosis should prompt goals of care discussion and involvement of a palliative care team when possible.

Mesenchymal stem cell transplantation in burn wound healing: uncovering the mechanisms of local regeneration and tissue repair

Burn injuries pose a significant healthcare burden worldwide, often leading to long-term disabilities and reduced quality of life. To explore the impacts of the transplantation of mesenchymal stem cells (MSCs) on the healing of burns and the levels of serum cytokines, 60 fully grown Sprague-Dawley rats were randomly divided into three groups (n = 20 each): group I (control), group II (burn induction), and group III (burn induction + bone marrow (BM)-MSC transplantation). Groups II and III were further divided into four subgroups (n = 5 each) based on euthanasia duration (7, 14, 21, and 28 days post transplant). The experiment concluded with an anesthesia overdose for rat death. After 7, 14, 21, and 28 days, the rats were assessed by clinical, laboratory, and histopathology investigations. The results revealed significant improvements in burn healing potentiality in the group treated with MSC. Furthermore, cytokine levels were measured, with significant increases in interleukin (IL)-6 and interferon alpha (IFN) observed, while IL-10 and transforming growth factor beta (TGF-β) decreased at 7 days and increased until 28 days post burn. Also, the group that underwent the experiment exhibited increased levels of pro-inflammatory cytokines and the anti-inflammatory cytokine IL-10 when compared to the control group. Histological assessments showed better re-epithelialization, neovascularization, and collagen deposition in the experimental group, suggesting that MSC transplantation in burn wounds may promote burn healing by modulating the immune response and promoting tissue regeneration.

The efficacy of adipose-derived stem cells in burn injuries: a systematic review

BACKGROUND

Burn injuries can be associated with prolonged healing, infection, a substantial inflammatory response, extensive scarring, and eventually death. In recent decades, both the mortality rates and long-term survival of severe burn victims have improved significantly, and burn care research has increasingly focused on a better quality of life post-trauma. However, delayed healing, infection, pain and extensive scar formation remain a major challenge in the treatment of burns. ADSCs, a distinct type of mesenchymal stem cells, have been shown to improve the healing process. The aim of this review is to evaluate the efficacy of ADSCs in the treatment of burn injuries.

METHODS

A systematic review of the literature was conducted using the electronic databases PubMed, Web of Science and Embase. The basic research question was formulated with the PICO framework, whereby the usage of ADSCs in the treatment of burns in vivo was determined as the fundamental inclusion criterion. Additionally, pertinent journals focusing on burns and their treatment were screened manually for eligible studies. The review was registered in PROSPERO and reported according to the PRISMA statement.

RESULTS

Of the 599 publications screened, 21 were considered relevant to the key question and were included in the present review. The included studies were almost all conducted on rodents, with one exception, where pigs were investigated. 13 of the studies examined the treatment of full-thickness and eight of deep partial-thickness burn injuries. 57,1 percent of the relevant studies have demonstrated that ADSCs exhibit immunomodulatory effects during the inflammatory response. 16 studies have shown improved neovascularisation with the use of ADSCs. 14 studies report positive influences of ADSCs on granulation tissue formation, while 11 studies highlight their efficacy in promoting re-epithelialisation. 11 trials demonstrated an improvement in outcomes during the remodelling phase.

CONCLUSION

In conclusion, it appears that adipose-derived stem cells demonstrate remarkable efficacy in the field of regenerative medicine. However, the usage of ADSCs in the treatment of burns is still at an early experimental stage, and further investigations are required in order to examine the potential usage of ADSCs in future clinical burn care.

Glomerular injury after trauma, burn, and sepsis

Acute kidney injury development after trauma, burn, or sepsis occurs frequently but remains a scientific and clinical challenge. Whereas the pathophysiological focus has mainly been on hemodynamics and the downstream renal tubular system, little is known about alterations upstream within the glomerulus post trauma or during sepsis. Particularly for the glomerular endothelial cells, mesangial cells, basal membrane, and podocytes, all of which form the glomerular filter, there are numerous in vitro studies on the molecular and functional consequences upon exposure of single cell types to specific damage- or microbial-associated molecular patterns. By contrast, a lack of knowledge exists in the real world regarding the orchestrated inflammatory response of the glomerulus post trauma or burn or during sepsis. Therefore, we aim to provide an overview on the glomerulus as an immune target but also as a perpetrator of the danger response to traumatic and septic conditions, and present major players involved in the context of critical illness. Finally, we highlight research gaps of this rather neglected but worthwhile area to define future molecular targets and therapeutic strategies to prevent or improve the course of AKI after trauma, burn, or sepsis.

Geniposide promotes wound healing of skin ulcers in diabetic rats through PI3K/Akt pathway

Continuously hyperglycation-induced lesion and poor blood flow contributed to the wound incurable and susceptible to infection. About fifteen percent of people with diabetes would develop ulcers during their lifetime, especially on the feet, which could lead to severe tissue destruction and eventual amputation. Various strategies were limited to accelerate wound healing in diabetic patients for high cost and unsatisfied effects. Geniposide is well-known for its anti-inflammation and anti-apoptosis in several pathological tissues. This study is to explore the protective effect of geniposide on wound healing rate, inflammatory response, nutritional function and cellular apoptosis in diabetic rats. Diabetic rats was induced by streptozotocin and defined as plasma glucose >300 mg/dl. Western blot and immunostaining technologies were performed to mark and quantify the target proteins. The oral administration of geniposide (200 mg/kg and 500 mg/kg) could significantly promote wound healing by the increment of lesion retraction in diabetic rats compared to model group. In the apoptotic study of skin wound in diabetic rats, the TUNEL-positive cells were greatly decreased in geniposide subgroups (P < 0.05). The levels of TNF-α, IL-1β and IL-6 were significantly inhibited by geniposide with the IC50 value of 470 mg/kg, 464 mg/kg and 370 mg/kg body weight respectively, which might be related to the enhancement of the phosphorylation of PI3K and Akt proteins. Geniposide enhanced the repairment of skin wound in diabetic rats by inhibiting inflammatory response and apoptosis.

Serum Selenium-Binding Protein 1 (SELENBP1) in Burn Injury: A Potential Biomarker of Disease Severity and Clinical Course

Oxidative stress, systemic inflammation, and metabolic derangements are hallmarks of burn pathophysiology. Severely burned patients are highly susceptible to infectious complications. Selenium-binding protein 1 (SELENBP1) modulates intracellular redox homeostasis, and elevated serum concentrations have been associated with adverse clinical outcomes in trauma patients. We hypothesized that serum SELENBP1 at hospital admission and during hospitalization may constitute a meaningful biomarker of disease severity and the clinical course in burn injury, with pulmonary infection as primary endpoint. To this end, we conducted a prospective cohort study that included 90 adult patients admitted to the Burn Center of the University Hospital Zurich, Switzerland. Patients were treated according to the local standard of care, with high-dose selenium supplementation during the first week. Serum SELENBP1 was determined at nine time-points up to six months postburn and the data were correlated to clinical parameters. SELENBP1 was initially elevated and rapidly declined within the first day. Baseline SELENBP1 levels correlated positively with the Abbreviated Burn Severity Index (ABSI) (R = 0.408; p < 0.0001). In multiple logistic regression, a higher ABSI was significantly associated with increased pulmonary infection risk (OR, 14.4; 95% CI, 3.2-88.8; p = 0.001). Similarly, baseline SELENBP1 levels constituted a novel but less accurate predictor of pulmonary infection risk (OR, 2.5; 95% CI, 0.7-8.9; p = 0.164). Further studies are needed to explore the additional value of serum SELENBP1 when stratifying patients with respect to the clinical course following major burns and, potentially, for monitoring therapeutic measures aimed at reducing tissue damage and oxidative stress.

Therapeutic Plasma exchange therapy in Burns

Severe burn injury affects the body in many devastating ways, the most severe being systemic inflammatory response syndrome. This results in a myriad of effects like increasing capillary permeability, thereby fluid loss. It also causes a surge in inflammatory mediators like interleukin (IL)-6, which further increases the capillary leak and fluid loss. This results in refractory hypotension in patients despite adequate fluid resuscitation. Plasma exchange has been used in the management of a number of illnesses with a significant inflammatory component, and, therefore can be considered to have a role in burn injury. In our article, we would like to share our experience of using therapeutic plasma exchange therapy in burn patient.

DEMOGRAPHICS TO DEFINE PEDIATRIC BURN PATIENTS AT RISK OF ADVERSE OUTCOMES

ABSTRACT

Background: There is currently no standard definition of a severe burn in the pediatric patient population to identify those at higher risk of infectious complications. Our aim was to correlate total burn surface area (TBSA), burn depth, and type of burn injury to nosocomial infection rates and systemic immune system responses to better define risk factors associated with adverse outcomes. Methods: A prospective observational study at a single-center, quaternary-care, American Burn Association-verified pediatric burn center was conducted from 2016 to 2021. Blood was collected within 72 h of injury from 103 pediatric patients. Whole blood was incubated with lipopolysaccharide or phytohemagglutinin stimulation reagent to measure innate and adaptive immune response, respectively. Flow cytometry was performed on whole blood samples to measure both innate and adaptive immune cells. Unstimulated plasma was also extracted, and IL-6 and IL-10 as well as soluble proteins B- and T-lymphocyte attenuator, CD27, and T-cell immunoglobulin mucin 3 were quantified. Results: There was a significant increased risk for nosocomial infection in pediatric patients with TBSA burns of ≥20%, full-thickness burn injuries ≥5%, or flame burn injuries. There was an overall decrease in both innate and adaptive immune function in patients with TBSA burns ≥20% or full-thickness burn injuries ≥5%. Both burn injury characteristics were also associated with a significant increase in unstimulated IL-6 and IL-10 and soluble immunoregulatory checkpoint proteins. We observed a significant decrease in soluble B- and T-lymphocyte attenuator for those with a flame injury, but there were no other differences between flame injury and scald/contact burns in terms of innate and adaptive immune function. Conclusion: Burns with ≥20% TBSA or ≥5% full thickness in pediatric patients are associated with systemic immune dysfunction and increased risk of nosocomial infections.

The Complexity of the Post-Burn Immune Response: An Overview of the Associated Local and Systemic Complications

Burn injury induces a complex inflammatory response, both locally and systemically, and is not yet completely unravelled and understood. In order to enable the development of accurate treatment options, it is of paramount importance to fully understand post-burn immunology. Research in the last decades describes insights into the prolonged and excessive inflammatory response that could exist after both severe and milder burn trauma and that this response differs from that of none-burn acute trauma. Persistent activity of complement, acute phase proteins and pro- and anti-inflammatory mediators, changes in lymphocyte activity, activation of the stress response and infiltration of immune cells have all been related to post-burn local and systemic pathology. This "narrative" review explores the current state of knowledge, focusing on both the local and systemic immunology post-burn, and further questions how it is linked to the clinical outcome. Moreover, it illustrates the complexity of post-burn immunology and the existing gaps in knowledge on underlying mechanisms of burn pathology.

Severe Burn Injury Significantly Alters the Gene Expression and m6A Methylation Tagging of mRNAs and lncRNAs in Human Skin

N6-methyladenosine (m6A) modulates RNA metabolism and functions in cell differentiation, tissue development, and immune response. After acute burns, skin wounds are highly susceptible to infection and poor healing. However, our understanding of the effect of burn injuries on m6A methylation and their potential mechanism is still limited. Human m6A-mRNA&lncRNA Epitranscriptomic microarray was used to obtain comprehensive mRNA and lncRNA transcriptome m6A profiling and gene expression patterns after burn injuries in human skin tissue. Bioinformatic and functional analyses were conducted to find molecular functions. Microarray profiling showed that 65 mRNAs and 39 lncRNAs were significantly hypermethylated; 5492 mRNAs and 754 lncRNAs were significantly hypomethylated. Notably, 3989 hypomethylated mRNAs were down-expressed and inhibited many wound healing biological processes and pathways including in the protein catabolic process and supramolecular fiber organization pathway; 39 hypermethylated mRNAs were up-expressed and influenced the cell surface receptor signaling pathway and inflammatory response. Moreover, we validated that m6A regulators (METTL14, METTL16, ALKBH5, FMR1, and HNRNPC) were significantly downregulated after burn injury which may be responsible for the alteration of m6A modification and gene expression. In summary, we found that homeostasis in the skin was disrupted and m6A modification may be a potential mechanism affecting trauma infection and wound healing.

Anti-inflammatory action of geniposide promotes wound healing in diabetic rats

CONTEXT

As a major active iridoid glycoside from Gardenia jasminoides J. Ellis (Rubiaceae), geniposide possesses various pharmacological activities, including anti-platelet aggregation and anti-inflammatory action.

OBJECTIVES

This study explores the effect of geniposide in diabetic wound model by anti-inflammatory action.

MATERIALS AND METHODS

Diabetic rodent model in Wistar rats was induced by streptozotocin combined with high-fat feed. The selected rats were divided into control group, the diabetic model group and geniposide subgroups (200, 400 and 500 mg/kg), and orally administrated once daily with saline or geniposide. Wound area and histochemical indicators were measured on day 7 after continuous administration, to assess lesion retraction, inflammatory cells and fibroblasts.

RESULTS

Geniposide notably enhanced lesion retraction by 1.06-1.84 times on day 7 after surgical onset in diabetic rats (p < 0.05). In the pathological experiment by HE staining, geniposide significantly reduced inflammatory cell infiltration and proliferation of fibroblasts in the central lesion regions. In diabetic rats treated with geniposide, the levels of pro-inflammatory factors (tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β)) and IL-6 were significantly reduced (p < 0.05), followed with the increment of IL-10 in a dose-dependent manner. The IC₅₀ of geniposide on TNF-α, IL-1β and IL-6 could be calculated as 1.36, 1.02 and 1.23 g/kg, respectively. It assumed that geniposide-induced IL-10 expression contributed to inhibiting the expression of pro-inflammatory factors.

DISCUSSION AND CONCLUSIONS

Geniposide promoted diabetic wound healing by anti-inflammation and adjusting blood glucose. Further topical studies are required to evaluate effects on antibacterial activity and skin regeneration.

An integrated cytokine and kynurenine network as the basis of neuroimmune communication

Two of the molecular families closely associated with mediating communication between the brain and immune system are cytokines and the kynurenine metabolites of tryptophan. Both groups regulate neuron and glial activity in the central nervous system (CNS) and leukocyte function in the immune system, although neither group alone completely explains neuroimmune function, disease occurrence or severity. This essay suggests that the two families perform complementary functions generating an integrated network. The kynurenine pathway determines overall neuronal excitability and plasticity by modulating glutamate receptors and GPR35 activity across the CNS, and regulates general features of immune cell status, surveillance and tolerance which often involves the Aryl Hydrocarbon Receptor (AHR). Equally, cytokines and chemokines define and regulate specific populations of neurons, glia or immune system leukocytes, generating more specific responses within restricted CNS regions or leukocyte populations. In addition, as there is a much larger variety of these compounds, their homing properties enable the superimposition of dynamic variations of cell activity upon local, spatially limited, cell populations. This would in principle allow the targeting of potential treatments to restricted regions of the CNS. The proposed synergistic interface of 'tonic' kynurenine pathway affecting baseline activity and the superimposed 'phasic' cytokine system would constitute an integrated network explaining some features of neuroimmune communication. The concept would broaden the scope for the development of new treatments for disorders involving both the CNS and immune systems, with safer and more effective agents targeted to specific CNS regions.

Cytokine Pathways in Cardiac Dysfunction following Burn Injury and Changes in Genome Expression

In 2016, an estimated 486,000 individuals sustained burn injuries requiring medical attention. Severe burn injuries lead to a persistent, hyperinflammatory response that may last up to 2 years. The persistent release of inflammatory mediators contributes to end-organ dysfunction and changes in genome expression. Burn-induced cardiac dysfunction may lead to heart failure and changes in cardiac remodeling. Cytokines promote the inflammatory cascade and promulgate mechanisms resulting in cardiac dysfunction. Here, we review the mechanisms by which TNFα, IL-1 beta, IL-6, and IL-10 cause cardiac dysfunction in post-burn injuries. We additionally review changes in the cytokine transcriptome caused by inflammation and burn injuries.

Early expression of IL-10, IL-12, ARG1, and NOS2 genes in peripheral blood mononuclear cells synergistically correlate with patient outcome after burn injury

BACKGROUND

No methods exist to rapidly and accurately quantify the immune insult created by burn injuries. The development of a rapid, noninvasive clinical biomarker assay that evaluates a burn patient's underlying immune dysfunction and predicts clinical outcomes could transform burn care. We aimed to determine a set of peripheral biomarkers that correlates with clinical outcomes of burn patients.

METHODS

This prospective observational study enrolled two patient cohorts within a single burn center into an institutionally approved institutional review board study. Blood draws were performed <48 hours after injury. Initial unbiased immune gene expression analysis compared 23 burn patients and 6 healthy controls using multiplex immune gene expression analysis of RNA from peripheral blood mononuclear cells. We then performed confirmatory outcomes analysis in 109 burn patients and 19 healthy controls using a targeted rapid quantitative polymerase chain reaction. Findings were validated and modeled associations with clinical outcomes using a regression model.

RESULTS

A total of 149 genes with a significant difference in expression from burn patients compared with controls were identified. Pathway analysis identified pathways related to interleukin (IL)-10 and inducible nitric oxide synthase signaling to have significant z scores. quantitative polymerase chain reaction analysis of IL-10, IL-12, arginase 1 (ARG1), and inducible nitric oxide synthase demonstrated that burn injury was associated with increased expression of ARG1 and IL-10, and decreased expression of nitric oxide synthase 2 (NOS2) and IL-12. Burn severity, acute lung injury, development of infection, failure of skin autograft, and mortality significantly correlated with expression of one or more of these genes. Ratios of IL-10/IL-12, ARG1/NOS2, and (ARG1-IL-10)/(NOS2-IL-12) transcript levels further improved the correlation with outcomes. Using a multivariate regression model, adjusting for patient confounders demonstrated that (ARG1-IL-10)/(NOS2-IL-12) significantly correlated with burn severity and development of acute lung injury.

CONCLUSION

We present a means to predict patient outcomes early after burn injury using peripheral blood, allowing early identification of underlying immune dysfunction.

LEVEL OF EVIDENCE

Prognostic/Epidemiological; Level II.

Ameliorative effect of bone marrow-derived mesenchymal stem cells on burn-induced hepatic and metabolic derangements in rats

AIMS

The current study aims to investigate the therapeutic potential of bone marrow-derived mesenchymal stem cells (MSCs) as a solo therapy in ameliorating both skin lesions and liver injury induced by cutaneous severe burn injury (SBI) in rats.

MAIN METHODS

In anesthetized male adult Wistar albino rats, 30 % total burn surface area and established hepatic injury was achieved via direct contact of each experimental animal's dorsum with heated metal rod (100 °C) for 10 s. On the next day following burn, human MSCs or mouse MSCs was administered locally around the burn site and intraperitonially (0.5 × 10⁶ cells/rat for each route) and outcomes were investigated at 4 and 14 days following burn induction.

KEY FINDINGS

Both types of MSCs significantly improved skin and liver histology, decreased liver enzymes, and ameliorated oxidative stress in hepatocytes of SBI-rats. Further, SBI-induced rises in hepatic apoptotic marker (caspase-3, Bax) and serum inflammatory markers (TNF-α, IL-1β, and IL-6) were reduced following either human or mouse MSC administration. In addition, MSCs augmented insulin receptor substrate-1, phosphorylated protein kinase-B (phospho-Akt), while alleviating serum glucose levels in SBI-rats. These previous effects persisted even at the 14-day time point.

SIGNIFICANCE

Following single administration, bone marrow-derived MSCs is capable of counteracting SBI-induced skin lesions as well as related hepatic complications, specifically via mitigating postburn hyperglycemia and hyperinflammation.

Modern aspects of burn injury immunopathogenesis and immuno-biochemical markers of wound healing (review of literature)

Burns are one of the most common traumatic injuries in the world, representing a global public health problem. Major burns (severe burn injury or burn disease) are one of the most life-threatening injuries. There is a great need to identify and monitor the development of complications (sepsis and septic shock, coagulopathy and DIC) in burned patients. The basis of the pathogenesis of burn injury, as well as any general pathological process, is an inflammatory reaction, ultimately aimed at restoring the structure and function of the damaged tissue. A feature of the inflammatory reaction in burn injury is the scale of alteration of the skin and mucous membranes. The review presents the main aspects of the burn injuries immunopathogenesis and the features of post-burn immune dysfunction, manifested by disorders in the innate and adaptive immunity systems. Attention is focused on the role in the immunopathogenesis of developing systemic and local disorders in burn injury. Also the role are discussed of a minor subpopulations of lymphocytes (Treg-, Th-17-, γδT-cells) in the immunopathogenesis and in the bacterial infection protection. The characteristics of the main immuno-biochemical markers of burn injury (cytokines and growth factors, nitric oxide, matrix metalloproteases, bacteria concentration levels) are present. The prognostic role of these biomarkers in assessing of the severity degree of patients with burn injury and wound healing processes is shown. The review has been compiled using references from major databases such as RSCI, Web of Science, PubMed, Scopus and Google Scholar (up to march 2022). After obtaining all reports from database, the papers were carefully analyzed in order to find data related to the topic of this review (60 references).

Early detection of soluble CD27, BTLA, and TIM-3 predicts the development of nosocomial infection in pediatric burn patients

Thermal injury induces concurrent inflammatory and immune dysfunction, which is associated with adverse clinical outcomes. However, these effects in the pediatric population are less studied and there is no standard method to identify those at risk for developing infections. Our goal was to better understand immune dysfunction and identify soluble protein markers following pediatric thermal injury. Further we wanted to determine which early inflammatory, soluble, or immune function markers are most predictive of the development of nosocomial infections (NI) after burn injury. We performed a prospective observational study at a single American Burn Association-verified Pediatric Burn Center. A total of 94 pediatric burn subjects were enrolled and twenty-three of those subjects developed a NI with a median time to diagnosis of 8 days. Whole blood samples, collected within the first 72 hours after injury, were used to compare various markers of inflammation, immune function, and soluble proteins between those who recovered without developing an infection and those who developed a NI after burn injury. Within the first three days of burn injury, innate and adaptive immune function markers (ex vivo lipopolysaccharide-induced tumor necrosis factor alpha production capacity, and ex vivo phytohemagglutinin-induced interleukin-10 production capacity, respectively) were decreased for those subjects who developed a subsequent NI. Further analysis of soluble protein targets associated with these pathways displayed significant increases in soluble CD27, BTLA, and TIM-3 for those who developed a NI. Our findings indicate that suppression of both the innate and adaptive immune function occurs concurrently within the first 72 hours following pediatric thermal injury. At the same time, subjects who developed NI have increased soluble protein biomarkers. Soluble CD27, BTLA, and TIM-3 were highly predictive of the development of subsequent infectious complications. This study identifies early soluble protein makers that are predictive of infection in pediatric burn subjects. These findings should inform future immunomodulatory therapeutic studies.

Intravenous iron therapy to treat burn anaemia: A retrospective cohort study

PURPOSE

Intravenous iron is an effective treatment for anaemia in many populations but has not been evaluated in those with burn anaemia. This study aimed to evaluate the efficacy and safety of intravenous iron to manage burn anaemia.

METHODOLOGY

This was a retrospective cohort study of patients admitted to the Royal Brisbane and Women's Hospital with burns to at least 15% total body surface area (TBSA). Data collected from patient records included demographics, treatment details, and outcomes including length of stay, blood transfusions, and serum haemoglobin concentrations. Linear mixed effects regression models were used to assess the effect of treatment with intravenous iron on haemoglobin over time.

RESULTS

Sixty patients met inclusion criteria, with 11 (18%) treated using intravenous iron. Those treated with intravenous iron had higher TBSA burns (median 39% vs 18%, P = 0.0005), more operations (3 vs 1, P = 0.0012), and more blood transfusions (median 8 units vs 0 units, P = 0.0002). One patient (9%) experienced a minor adverse drug reaction from intravenous iron. When examining the change in modelled haemoglobin levels over the first 14 days following the last major operation, the change in the intravenous iron group (11.22 g/L) was 14.56 g/L greater than the change in the group not receiving intravenous iron (-3.34 g/L, P = 0.0282).

CONCLUSION

This exploratory study provides preliminary evidence of benefit and safety of intravenous iron treatment on burn anaemia recovery.

Measures of Adaptive Immune Function Predict the Risk of Nosocomial Infection in Pediatric Burn Patients

Thermal injury results in changes in the inflammatory and innate immune response of pediatric patients. Plasma cytokines, cellular profiles, and reduction in innate immune function following burn injury has also been correlated to adverse outcomes (e.g., mortality and infectious complications). Changes in adaptive immune function following thermal injury are not as well characterized. Our goal was to better understand if adaptive immune dysfunction occurs early after pediatric thermal injury and is a risk factor for nosocomial infections (NI). A prospective, longitudinal immune function observational study was performed at a single ABA-verified pediatric burn center. Eighty burn patients were enrolled with 20 developing a NI, defined using CDC criteria. We collected whole blood samples from pediatric burn patients within the first 72 hours from injury and between days 4-7, where applicable to analyze adaptive immune function. We compared immune function between burn patients who went on to develop NI and those that did not. Within the first 72 hours of injury, burn patients who developed NI had significantly lower absolute CD4+ lymphocyte counts and whole blood ex vivo phytohemagglutinin (PHA)-induced IFNγ and IL-10 production capacity compared to those that did not develop infection. Further analysis using receiver operating characteristic curve revealed that PHA-induced IL-10 production capacity had the highest area under the curve. Our data demonstrates early adaptive immune suppression occurs following pediatric thermal injury and PHA-induced IL-10 production capacity appears to be a predictor for the development of NI.

Hypoxia-Inducible Factors and Burn-Associated Acute Kidney Injury-A New Paradigm?

O₂ deprivation induces stress in living cells linked to free-radical accumulation and oxidative stress (OS) development. Hypoxia is established when the overall oxygen pressure is less than 40 mmHg in cells or tissues. However, tissues and cells have different degrees of hypoxia. Hypoxia or low O₂ tension may be present in both physiological (during embryonic development) and pathological circumstances (ischemia, wound healing, and cancer). Meanwhile, the kidneys are major energy-consuming organs, being second only to the heart, with an increased mitochondrial content and O₂ consumption. Furthermore, hypoxia-inducible factors (HIFs) are the key players that orchestrate the mammalian response to hypoxia. HIFs adapt cells to low oxygen concentrations by regulating transcriptional programs involved in erythropoiesis, angiogenesis, and metabolism. On the other hand, one of the life-threatening complications of severe burns is acute kidney injury (AKI). The dreaded functional consequence of AKI is an acute decline in renal function. Taking all these aspects into consideration, the aim of this review is to describe the role and underline the importance of HIFs in the development of AKI in patients with severe burns, because kidney hypoxia is constant in the presence of severe burns, and HIFs are major players in the adaptative response of all tissues to hypoxia.

Innate Immune System Response to Burn Damage-Focus on Cytokine Alteration

In the literature, burns are understood as traumatic events accompanied by increased morbidity and mortality among affected patients. Their characteristic feature is the formation of swelling and redness at the site of the burn, which indicates the development of inflammation. This reaction is not only important in the healing process of wounds but is also responsible for stimulating the patient’s innate immune system. As a result of the loss of the protective ability of the epidermis, microbes which include bacteria, fungi, and viruses have easier access to the system, which can result in infections. However, the patient is still able to overcome the infections that occur through a cascade of cytokines and growth factors stimulated by inflammation. Long-term inflammation also has negative consequences for the body, which may result in multi-organ failure or lead to fibrosis and scarring of the skin. The innate immune response to burns is not only immediate, but also severe and prolonged, and some people with burn shock may also experience immunosuppression accompanied by an increased susceptibility to fatal infections. This immunosuppression includes apoptosis-induced lymphopenia, decreased interleukin 2 (IL-2) secretion, neutrophil storm, impaired phagocytosis, and decreased monocyte human leukocyte antigen-DR. This is why it is important to understand how the immune system works in people with burns and during infections of wounds by microorganisms. The aim of this study was to characterize the molecular pathways of cell signaling of the immune system of people affected by burns, taking into account the role of microbial infections.

Large animal models of thermal injury

Burn injury results in a triad of inter-related adaptive responses: a systemic inflammatory response, a stress response, and a consequent hypermetabolic state which supports the former two. These pathological responses extend beyond the site of injury to affect distant organs and influence long-term outcomes in the patient. Animal models have proven valuable in advancing our understanding of mechanisms underlying the multifactorial manifestations of burn injury. While rodent models have been unprecedented in providing insights into signaling pathways, metabolic responses, protein turnover, cellular and molecular changes; small animal models do not replicate hypermetabolism, hyperinflammation, and wound healing after a burn injury as seen in humans. Herein, we provide a concise review of preferred large animal models utilized to understand burn pathophysiology based on organ systems and associated dysfunction. Additionally, we present a detailed protocol of contact burn injury in the Yorkshire pig model with a focus on preoperative care, anesthesia, analgesia, wound excision and grafting, dressing application, and frequency of dressing changes.

Small animal models of thermal injury

Burns are a severe form of trauma that account for 1.1 million cases necessitating medical attention and 4500 mortalities annually in the United States alone. Importantly, the initial trauma is succeeded by extensive, prolonged physiological alterations that detrimentally impact multiple organ systems. Given the complexity of post-burn pathophysiology, in vitro experiments are insufficient to model thermal injuries. Therefore, compatible animal burn models are essential for studying burn-related phenomena. In this chapter, we discuss commonly employed small animal burn models and their comparability and applicability to human studies. In particular, we compare post-burn wound healing between the species as well as relevant hypermetabolic and inflammatory characteristics, providing a better understanding of the pros and cons of utilizing a small animal surrogate for human burns. We further provide an overview of the rodent scald burn model methodology as well as a comparison between elderly, aged and young animals, providing a guide for tailoring animal model choice based on the relevant research question.

Therapeutic Effect of Darkling Beetle (Zophobas morio) Hemolymph on Skin Thermal Injury in Mice Infected by Staphylococcus haemolyticus

Staphylococci are the most common pathogens isolated from skin infections in livestock or companion animals. Antibiotic therapy is the best treatment for infections, but local or systemic use of antimicrobials increases the risk of bacterial resistance. Insects are rich in antimicrobial peptides, which can reduce bacterial resistance and can be used to treat bacterial infections after skin burns. We propose that the use of the darkling beetle (Z. morio) hemolymph to treat skin infections in mice by Staphylococcus haemolyticus is one of the alternatives. Z. morio hemolymph alleviated the increase in wound area temperature in mice with a skin infection, reduced the bacterial load of the wound, and accelerated the wound healing speed significantly. Pathological sections showed that Z. morio hemolymph can significantly reduce inflammatory cell infiltration, and promote skin tissue repair. Real-time fluorescent quantitative polymerase chain reaction (PCR) revealed that the Z. morio hemolymph can significantly reduce the levels of pro-inflammatory cytokines, including interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and chemokine interleukin-8 (IL-8). Our findings suggest that Z. morio antibacterial hemolymph can promote wound contraction, relieve local inflammatory responses and promote wound healing in mice infected with a heat injury, which has a positive therapeutic effect and enormous potential for skin thermal injury.

Early Transcriptomic Response to Burn Injury: Severe Burns Are Associated With Immune Pathway Shutdown

Burn injury induces a systemic hyperinflammatory response with detrimental side effects. Studies have described the biochemical changes induced by severe burns, but the transcriptome response is not well characterized. The goal of this work is to characterize the blood transcriptome after burn injury. Burn patients presenting to a regional center between 2012 and 2017 were prospectively enrolled. Blood was collected on admission and at predetermined time points (hours 2, 4, 8, 12, and 24). RNA was isolated and transcript levels were measured with a gene expression microarray. To identify differentially regulated genes (false-discovery rate ≤0.1) by burn injury severity, patients were grouped by TBSA above or below 20% and statistically enriched pathways were identified. Sixty-eight patients were analyzed, most patients were male with a median age of 41 (interquartile range, 30.5-58.5) years, and TBSA of 20% (11%-34%). Thirty-five patients had % TBSA injury ≥20%, and this group experienced greater mortality (26% vs 3%, P = .008). Comparative analysis of genes from patients with </≥20% TBSA revealed 1505, 613, 380, 63, 1357, and 954 differentially expressed genes at hours 0, 2, 4, 8, 12, and 24, respectively. Pathway analysis revealed an initial up-regulation in several immune/inflammatory pathways within the ≥20% TBSA groups followed by shutdown. Severe burn injury is associated with an early proinflammatory immune response followed by shutdown of these pathways. Examination of the immunoinflammatory response to burn injury through differential gene regulation and associated immune pathways by injury severity may identify mechanistic targets for future intervention.

Gut Microbial Changes and their Contribution to Post-Burn Pathology

ABSTRACT

Burn injuries are a common form of traumatic injury that leads to significant morbidity and mortality worldwide. Burn injuries are characterized by inflammatory processes and alterations in numerous organ systems and functions. Recently, it has become apparent that the gastrointestinal bacterial microbiome is a key component of regulating the immune response and recovery from burn and can also contribute to significant detrimental sequelae after injury, such as sepsis and multiple organ failure. Microbial dysbiosis has been linked to multiple disease states; however, its role in exacerbating acute traumatic injuries, such as burn, is poorly understood. In this article, we review studies that document changes in the intestinal microbiome after burn injury, assess the implications in post-burn pathogenesis, and the potential for further discovery and research.

Determination of Serum Levels of Interleukin-6, Interleukin-8, Interleukin-10, and Tumor Necrosis-Alpha and their Relationship With The Total Body Surface Area in Children

There are few studies on the inflammatory processes and the role of cytokines involved in pediatric burn injuries. The present study aims to measure the serum levels of cytokines and their relationship with the degree of burn injury in children. Within the 48 hours of hospitalization, the serum samples were obtained to measure inflammatory cytokines (interleukin-6, interleukin-8, interleukin-10 [IL-6, IL-8, and IL-10] and tumor necrosis factor-alpha [TNF-α]). The level of all of these cytokine factors was assessed by enzyme-linked immunosorbent assay technique. The mean levels of IL-6, IL-8, IL-10, and TNF-α was 18.15 ± 4.77 pg/ml, 59.54 ± 4.59 pg/ml, 8.41 ± 2.09 pg/ml, and 1.48 ± 0.15 pg/ml, respectively, which were higher than the normal range designated for the healthy pediatrics age group. The levels of TNF-α were higher in patients with sepsis (P = .03) and deceased patients (P = .001). There was a statistically significant difference in the levels of IL-8 in patients with second- (.001) and third-degree (.001) burn injuries in comparison to the first-degree burn injuries, and the level of IL-8 was statistically significantly higher in patients with electrical burn injuries in comparison to scald burn injuries (.01). IL-10 was statistically significantly higher in patients with contact burn injuries in comparison to scald (.001) and flame (.03) burn injuries. Cytokine levels in pediatric burn patients increased after severe burn injuries. There was a significant correlation between the levels of IL-8 and the degree of burn injuries.

Plasma extracellular vesicles released after severe burn injury modulate macrophage phenotype and function

Extracellular vesicles (EVs) have emerged as key regulators of immune function across multiple diseases. Severe burn injury is a devastating trauma with significant immune dysfunction that results in an ∼12% mortality rate due to sepsis-induced organ failure, pneumonia, and other infections. Severe burn causes a biphasic immune response: an early (0-72 h) hyper-inflammatory state, with release of damage-associated molecular pattern molecules, such as high-mobility group protein 1 (HMGB1), and proinflammatory cytokines (e.g., IL-1β), followed by an immunosuppressive state (1-2+ wk post injury), associated with increased susceptibility to life-threatening infections. We have reported that early after severe burn injury HMGB1 and IL-1β are enriched in plasma EVs. Here we tested the impact of EVs isolated after burn injury on phenotypic and functional consequences in vivo and in vitro using adoptive transfers of EV. EVs isolated early from mice that underwent a 20% total body surface area burn injury (burn EVs) caused similar hallmark cytokine responses in naïve mice to those seen in burned mice. Burn EVs transferred to RAW264.7 macrophages caused similar functional (i.e., cytokine secretion) and immune gene expression changes seen with their associated phase of post-burn immune dysfunction. Burn EVs isolated early (24 h) induced MCP-1, IL-12p70, and IFNγ, whereas EVs isolated later blunted RAW proinflammatory responses to bacterial endotoxin (LPS). We also describe significantly increased HMGB1 cargo in burn EVs purified days 1 to 7 after injury. Thus, burn EVs cause immune outcomes in naïve mice and macrophages similar to findings after severe burn injury, suggesting EVs promote post-burn immune dysfunction.

An exploratory study demonstrating that salivary cytokine profiles are altered in children with small area thermal injury

Serum can be used to investigate changes in cytokine concentration following burn injury in children, however for children receiving treatment in an outpatient setting, blood is not routinely collected and therefore cannot be used for monitoring. The aim of this study was to investigate the use of saliva as a non-invasive tool for predicting burn outcomes by measuring the concentration of salivary cytokines in children with small area burns. A multiplex cytokine assay was used to measure 17 cytokines in the saliva of paediatric patients with burns (n = 20) and healthy controls (n = 20). After the removal of cytokines that had >30% of samples below the assay lower detection limit, six cytokines including IL-1β, IL-4, IL-7, IL-8, MCP-1 and TNFα were analysed for association with burns. IL-1β and IL-4 were found to be significantly elevated in the paediatric burn patients compared to healthy controls. Interestingly, IL-1β was also significantly elevated in scald burns, compared to contact burns. In addition, biologically meaningful differences in cytokine concentration were identified in patients with different burn characteristics, which warrant further investigation. This exploratory study provides evidence that cytokines can be detected in the saliva of children and that salivary cytokine profiles differ between healthy controls and children with burns. Overall, this study demonstrates the value of saliva for the investigation of cytokines and its potential application in paediatric diagnostics, specifically in situations where blood collection is not appropriate.

Internalization of Neutrophil-Derived Microvesicles Modulates TNFα-Stimulated Proinflammatory Cytokine Production in Human Fibroblast-Like Synoviocytes

Neutrophil-derived microvesicles (NDMVs) have the potential to exert anti-inflammatory effects. Our study aimed to explore the effects of NDMVs on proinflammatory cytokines expressed by tumor necrosis factor α (TNFα)-stimulated fibroblast-like synoviocytes (FLS). FLS were isolated from the synovium of knee osteoarthritis (OA) patients undergoing surgery. NDMVs, isolated from TNFα-stimulated healthy neutrophils, were characterized by electron microscopy and nanoparticle tracking analysis. MTT and scratch wound healing assays were used to measure FLS viability and migration after treatment with NDMVs, while internalization of fluorescently labeled NDMVs was appraised by flow cytometry and confocal microscopy. Levels of proinflammatory cytokines in supernatants were quantified by the Bio-Plex system. Incubation of FLS with NDMVs at a vesicle/cell ratio of 100 resulted in a time-dependent uptake, with 35% of synoviocytes containing microvesicles over a 6–24 h time period, with no significant change in cell viability. TNFα stimulated the cytokine expression in FLS, and NDMVs down-regulated TNFα-induced expression of IL-5, IL-6, IL-8, MCP-1, IFNγ and MIP-1β. However, this down-regulation was selective, as NDMVs had no significant effects on TNFα-stimulated expression of IL-2 or IL-4. NDMVs were internalized by FLS to inhibit TNFα-stimulated broad-spectrum proinflammatory cytokine secretion. NDMVs, therefore, may exhibit an anti-inflammatory role in the regulation of the FLS function.

Glucose Metabolism in Burns-What Happens?

Severe burns represent an important challenge for patients and medical teams. They lead to profound metabolic alterations, trigger a systemic inflammatory response, crush the immune defense, impair the function of the heart, lungs, kidneys, liver, etc. The metabolism is shifted towards a hypermetabolic state, and this situation might persist for years after the burn, having deleterious consequences for the patient's health. Severely burned patients lack energy substrates and react in order to produce and maintain augmented levels of glucose, which is the fuel "ready to use" by cells. In this paper, we discuss biological substances that induce a hyperglycemic response, concur to insulin resistance, and determine cell disturbance after a severe burn. We also focus on the most effective agents that provide pharmacological modulations of the changes in glucose metabolism.

Early protein C activation is reflective of burn injury severity and plays a critical role in inflammatory burden and patient outcomes

BACKGROUND

Navigating the complexities of a severe burn injury is a challenging endeavour where the natural course of some patients can be difficult to predict. Straddling both the coagulation and inflammatory cascades that feature strongly in the burns systemic pathophysiology, we propose the pleiotropic protein C (PC) system may produce a viable biomarker to assist traditional evaluation methods for diagnostic and prognostic purposes.

METHODS

We enrolled 86 patients in a prospective observational cohort study. Over three weeks, serial blood samples were taken and measured for PC, activated (A)PC, their receptor endothelial protein C receptor (EPCR), and a panel of inflammatory cytokines including C-reactive protein (CRP), tumour necrosis factor-α, interleukin (IL)-1β, IL-6, IL-8, and IL-17. Their temporal trends were analysed alongside clinical factors including burn size, burn depth, presence of inhalational injury, and a composite outcome of requiring increased support.

RESULTS

(i) APC increased from a nadir on Day 3 (2.3±2.1ng/mL vs 4.1±2.5ng/mL by Day 18, p<0.0005), only becoming appropriately correlated to PC from Day 6 onwards (r=0.412-0.721, p<0.05 for all Days 6-21). (ii) This early disturbance in the PC system was amplified in the more severe burns (≥30% total body surface area, predominantly full thickness, or with inhalational injury), which were characterised by a marked fall in PC activation (approximated by APC/PC ratio) and APC levels during Days 0-3 with low unchanged PC levels. Critically low levels of this cytoprotective agent was associated with greater inflammatory burden, as reflected by significantly elevated CRP, IL-6, and IL-8 levels in the more severe compared to less severe burns, and by negative correlations between both PC and APC with most inflammatory cytokines. (iii) Alongside clinical markers of severity at admission (burn size, burn depth, and presence of inhalational injury), only Day 0 APC/PC ratio (OR 1.048 (1.014-1.083), p=0.006), APC (OR 1.364 (1.032-1.803), p=0.029), PC (OR 0.899 (0.849-0.953), p<0.0005), and not any inflammatory cytokines were predictive markers of requiring increased support. Uniquely, decreased Day 0 PC was further individually associated with each increased total length of stay, ICU length of stay, intravenous fluid resuscitation, and total surgeries, as well as possibly mortality.

CONCLUSION

An early functional depletion of the cytoprotective PC system provides a physiological link between severe burns and the cytokine storm, likely contributing to worse outcomes. Our findings on the changes in APC, PC and PC activation during this pathological state support APC and PC as early diagnostic and prognostic biomarkers, and provides a basis for their therapeutic potential in severe burn injuries.

Post-injury immunosuppression and secondary infections are caused by an AIM2 inflammasome-driven signaling cascade

Loss of lymphocytes, particularly T cell apoptosis, is a central pathological event after severe tissue injury that is associated with increased susceptibility for life-threatening infections. The precise immunological mechanisms leading to T cell death after acute injury are largely unknown. Here, we identified a monocyte-T cell interaction driving bystander cell death of T cells in ischemic stroke and burn injury. Specifically, we found that stroke induced a FasL-expressing monocyte population, which led to extrinsic T cell apoptosis. This phenomenon was driven by AIM2 inflammasome-dependent interleukin-1β (IL-1β) secretion after sensing cell-free DNA. Pharmacological inhibition of this pathway improved T cell survival and reduced post-stroke bacterial infections. As such, this study describes inflammasome-dependent monocyte activation as a previously unstudied cause of T cell death after injury and challenges the current paradigms of post-injury lymphopenia.

Respiratory Burst and TNF-α Receptor Expression of Neutrophils after Sepsis and Severe Injury-Induced Inflammation in Children

Systemic inflammatory response syndrome (SIRS) is defined as the systemic host response to infection or a non-infectious factor. The purpose of this study was to evaluate the involvement of reactive oxygen species (ROS) in severe inflammation and to assess the discrimination strength of the neutrophil BURSTTEST assay regarding its etiology in three groups of patients (sepsis, burns, and bone fractures) who met the SIRS criteria. The neutrophil activation (respiratory burst of granulocytes as well as p55 and p75 tumor necrosis factor (TNF-α) receptor expression) was evaluated twice using flow cytometry, and the results were compared with healthy controls and among SIRS subjects. A decreased oxygen metabolism in neutrophils after E.coli stimulation and increased TNF-α receptor expression were found in septic and burned patients on admission, while ROS production augmented and TNF-α receptor expression diminished with the applied therapy. The significant differences in neutrophil respiratory burst intensity among septic and burned patients and those with sepsis and bone fractures were found (however, there were not any such differences between patients with thermal and mechanical injuries). This study indicates that the neutrophil BURSTTEST evaluation might be a clinically reliable marker for differentiating the SIRS etiology.

A review of potential biomarkers for assessing physical and psychological trauma in paediatric burns

Biological markers that evaluate physical healing as well as psychological impact of a burn are essential for effective treatment of paediatric burns. The objective of this review is to summarize the evidence supporting the use of biomarkers in children with burns. An extensive review of the literature was performed using PubMed. A total of 59 biomarkers were identified relating to burn presence, specifically relating to processes involved in inflammation, wound healing, growth and metabolism. In addition, biomarkers involved in the stress response cascade following a burn trauma were also identified. Although many biomarkers have been identified that are potentially associated with burn-related physical and psychological trauma, an understanding of burn biology is still lacking in children. We propose that future research in the field of children’s burns should be conducted using broad screening methods for identifying potential biomarkers, examine the biological interactions of different biomarkers, utilize child-appropriate biological fluids such as urine or saliva, and include a range of different severity burns. Through further research, the biological response to burn injury may be fully realized and clinically relevant diagnostic tests and treatment therapies utilizing these biomarkers could be developed, for the improvement of healing outcomes in paediatric burn patients.

The pathogenesis and diagnosis of sepsis post burn injury

Burn is an under-appreciated trauma that is associated with unacceptably high morbidity and mortality. Although the survival rate after devastating burn injuries has continued to increase in previous decades due to medical advances in burn wound care, nutritional and fluid resuscitation and improved infection control practices, there are still large numbers of patients at a high risk of death. One of the most common complications of burn is sepsis, which is defined as “severe organ dysfunction attributed to host's disordered response to infection” and is the primary cause of death in burn patients. Indeed, burn injuries are accompanied by a series of events that lead to sepsis and multiple organ dysfunction syndrome, such as a hypovolaemic state, immune and inflammatory responses and metabolic changes. Therefore, clear diagnostic criteria and predictive biomarkers are especially important in the prevention and treatment of sepsis and septic shock. In this review, we focus on the pathogenesis of burn wound infection and the post-burn events leading to sepsis. Moreover, the clinical and promising biomarkers of burn sepsis will also be summarized.

Identification of differentially expressed long non-coding RNAs in mice intestines after severe burns and a preliminary study into the key gene H19

BACKGROUND

The intestine is considered the key organ in stress response to severe burns and injury to intestine after severe burns can be fatal. However, the injury and subsequent repair of intestinal tissues after severe burns at the genetic level are poorly understood. Long non-coding RNAs (lncRNAs) have important functions in regulating many biological processes, including gene transcription and translation. Autophagy is a process of intracellular degradation and reutilization of cytoplasmic proteins and organelles.

METHODS

We herein analyzed the genome-wide expression profile of lncRNAs and mRNAs after severe burns in the intestines of mice by lncRNA microarray. qRT-PCR was performed to verify the reliability of microarray analysis results, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were used for bioinformatics analysis of differentially expressed mRNAs. The common regulatory network between the top ten differentially expressed lncRNAs and trans-related mRNAs was visualized by Cytoscape (v3.7.2). Next, we hypothesized that H19 is the key gene for intestinal mucosal repair. After H19 was overexpressed, the changes in downstream autophagy protein expression levels were observed.

RESULTS

GO and KEGG analysis indicated that the differentially expressed mRNAs were mainly enriched in a cell cycle- and mitosis-related genes.Overexpression of lncRNA-H19 showed that the autophagy-related gene Trim21 was up-regulated, while HIF1α was down-regulated.

CONCLUSION

LncRNA-H19 played a key role in repairing the intestinal mucosa, and overexpression of lncRNA-H19 activated autophagy and migration of intestinal epithelial cells (IEC-6).

A novel human ex vivo skin model to study early local responses to burn injuries

Burn injuries initiate numerous processes such as heat shock response, inflammation and tissue regeneration. Reliable burn models are needed to elucidate the exact sequence of local events to be able to better predict when local inflammation triggers systemic inflammatory processes. In contrast to other ex vivo skin culture approaches, we used fresh abdominal skin explants to introduce contact burn injuries. Histological and ultrastructural analyses confirmed a partial-thickness burn pathology. Gene expression patterns and cytokine production profiles of key mediators of the local inflammation, heat shock response, and tissue regeneration were analyzed for 24 h after burn injury. We found significantly increased expression of factors involved in tissue regeneration and inflammation soon after burn injury. To investigate purely inflammation-mediated reactions we injected lipopolysaccharide into the dermis. In comparison to burn injury, lipopolysaccharide injection initiated an inflammatory response while expression patterns of heat shock and tissue regeneration genes were unaffected for the duration of the experiment. This novel ex vivo human skin model is suitable to study the local, early responses to skin injuries such as burns while maintaining an intact overall tissue structure and it gives valuable insights into local mechanisms at the very beginning of the wound healing process after burn injuries.

[Current place of cultured epithelial autografts in the management of massive burns and future prospects: Literature review]

Cultured Epithelial Autografts (CEAs), developed at the end of the 1970s from in vitro culture amplification of keratinocytes, have led to a therapeutic revolution in the treatment of major burns. The areas of improvement of the cultures initially involved the manufacturing processes (culture media, support matrices, etc.) and then clinical applications (use of a largely expanded allogeneic or autologous dermal bed). These advances have enabled burn centers (BC) using CEAs to obtain very satisfactory percentages of graft integration and survival of major burns patients. However, since CEAs are not without major drawbacks (fragility, high rate of infection, high cost, unstable scars), these pitfalls have restricted their use worldwide. As of 2014, CEAs produced by Genyzme Tissue Repair are no longer available in Europe, which has considerably reduced an indispensable therapeutic arsenal for severe and extensive burns. To overcome these therapeutic limitations, current research is focusing on techniques combining surgery, tissue engineering and cell therapy. The advent of regenerative medicine, based on the use of stem cells, in particular mesenchymal stem cells (MSC), can contribute to an improvement in the management of these massively burned patients (optimization of the environmental medium, attenuation of the systemic inflammatory response and the immunosuppressive effects of the burn, acceleration of tissue regeneration, etc.). Cell therapy, therefore, offers alternatives to CEAs, which must imperatively retain their place in the therapeutic arsenal, namely an effective emergency coverage technique that can be improved.

Measures of Systemic Innate Immune Function Predict the Risk of Nosocomial Infection in Pediatric Burn Patients

Critical injury-induced immune suppression has been associated with adverse outcomes. This acquired form of immunosuppression is poorly understood in pediatric burn patients, who have infectious complication rates as high as 71%. Our primary objectives were to determine if thermal injury results in early innate immune dysfunction and is associated with increased risk for nosocomial infections (NI). We performed a prospective, longitudinal immune function observational study at a single pediatric burn center. Whole blood samples from burn patients within the first week of injury were used to assess innate immune function. Nosocomial infections were defined using CDC criteria. Immune parameters were compared between patients who went on to develop NI and those that did not. We enrolled a total of 34 patients with 12 developing a NI. Within the first 3 days of injury, children whom developed NI had significantly lower whole blood ex vivo LPS-induced TNFα production capacity (434 pg/mL vs 960 pg/mL, P = .0015), CD14+ monocyte counts (273 cells/µL vs 508 cells/µL, P = .01), and % HLA-DR expression on CD14+ monocytes (54% vs 92%, P = .02) compared with those that did not develop infection. Plasma cytokine levels did not have a significant difference between the NI and no NI groups. Early innate immune suppression can occur following pediatric thermal injury and appears to be a risk factor for the development of nosocomial infections. Plasma cytokines alone may not be a reliable predictor of the development of NI.

Plasma TNFα and Unknown Factor/s Potentially Impede Erythroblast Enucleation Obstructing Terminal Maturation of Red Blood Cells in Burn Patients

INTRODUCTION

In this study, using burn patient's peripheral blood mononuclear cells (PBMCs), we have shown that the Epo independent stage of terminal enucleation to reticulocyte formation is impeded in the presence of autologous plasma (BP). Furthermore, substitution with allogeneic control plasma (CP) from the healthy individual in place of BP rectified this enucleation defect. The exclusive role of burn microenvironment in late-stage erythropoiesis defect was further demarcated through control healthy human bone marrow cells cultured in the presence of CP, BP, and cytokines.

METHODS

PBMCs and human bone marrow (huBM) were differentiated ex vivo to enucleated reticulocytes in the presence of required growth factors and 5% CP or BP. Effect of systemic mediators in burn microenvironment like IL-6, IL-15, and TNFα was also explored. Neutralization experiments were carried out by adding varying concentrations (25 ng-400 ng/mL) of Anti-TNFα Ab to either CP+TNFα or BP.

RESULTS

Reticulocyte proportion and maturation index were significantly improved upon substituting BP with CP during differentiation of burn PBMCs. In the huBM ex vivo culture, addition of IL-6 and IL-15 to CP inhibited the proliferation stages of erythropoiesis, whereas TNFα supplementation caused maximum diminution at erythroblast enucleation stage. Supplementation with anti-TNFα in the BP showed significant but partial restoration in the enucleation process, revealing the possibility of other crucial microenvironmental factors that could impact RBC production in burn patients.

CONCLUSION

Exogenous TNFα impairs late-stage erythropoiesis by blocking enucleation, but neutralization of TNFα in BP only partially restored terminal enucleation indicating additional plasma factor(s) impair(s) late-stage RBC maturation in burn patients.