Impaired Immune Response in Elderly Burn Patients: New Insights Into the Immune-senescence Phenotype

Burns in the Elderly

Burns in the elderly are a significant cause of morbidity and mortality. Frailty is an important indicator of patient health and physiologic reserve. Comorbidities and typical age-related changes significantly impact the outcomes of elderly burn patients and decisions made during their burn care. It is essential to have early and thorough discussions about the goals of care and rehabilitation plans. Physiologic changes that occur from aging cause slower wound healing and may make operative treatment more challenging, although techniques such as autographing, skin substitutes, and flaps may all play a role in treating this patient population.

The preoperative geriatric nutritional risk index predicts long-term prognosis in elderly locally advanced rectal cancer patients: a two-center retrospective cohort study

BACKGROUND

The objective is to explore the value of preoperative geriatric nutritional risk index (GNRI) in evaluating long-term prognosis in elderly locally advanced rectal cancer (LARC) patients who accepted neoadjuvant chemoradiotherapy (NCRT) and to compare GNRI with established nutritional markers, including prognostic nutritional index (PNI) and controlling nutritional status (CONUT) score.

METHODS

Preoperative GNRI was retrospectively assessed in 172 LARC patients aged ≥ 60 years who underwent radical resection after NCRT at two centers. Optimal cutoff value of GNRI was determined by X-tile program. The association of GNRI with clinicopathological parameters and nutritional markers was analyzed. The survival ability of markers was evaluated using time-dependent receiver-operating characteristic (ROC) curve analysis. Finally, survival analysis was performed using Kaplan-Meier and Cox regression analysis.

RESULTS

GNRI was highly correlated with nutritional markers. An optimal cutoff value for the GNRI was 96. In the time-dependent ROC curve, GNRI demonstrated a stable predictive ability for both disease-free survival (DFS) and overall survival (OS). Multivariate analysis showed that GNRI was the only nutritional marker that independently predicted DFS (HR 2.457, 95% CI 1.066-5.665, P = 0.035) and OS (HR 9.002, 95% CI 3.100-26.146, P < 0.001). As an additional benefit, GNRI was able to stratify survival in subgroups of ypTNM and tumor response.

CONCLUSION

Preoperative GNRI is a promising predictor of long-term survival for elderly LARC patients undergoing NCRT, superior to the established nutritional markers.

Treatment of infection and inflammation associated with COVID-19, multi-drug resistant pneumonia and fungal sinusitis by nebulizing a nanosilver solution

Solutions containing Ag⁰ nanoclusters, Ag⁺¹, and higher oxidation state silver, generated from nanocrystalline silver dressings, were anti-inflammatory against porcine skin inflammation. The dressings have clinically-demonstrated broad-spectrum antimicrobial activity, suggesting application of nanosilver solutions in treating pulmonary infection. Nanosilver solutions were tested for antimicrobial efficacy; against HSV-1 and SARS-CoV-2; and nebulized in rats with acute pneumonia. Patients with pneumonia (ventilated), fungal sinusitis, burns plus COVID-19, and two non-hospitalized patients with COVID-19 received nebulized nanosilver solution. Nanosilver solutions demonstrated pH-dependent antimicrobial efficacy; reduced infection and inflammation without evidence of lung toxicity in the rat model; and inactivated HSV-1 and SARS-CoV-2. Pneumonia patients had rapidly reduced pulmonary symptoms, recovering pre-illness respiratory function. Fungal sinusitis-related inflammation decreased immediately with infection clearance within 21 days. Non-hospitalized patients with COVID-19 experienced rapid symptom remission. Nanosilver solutions, due to anti-inflammatory, antiviral, and antimicrobial activity, may be effective for treating respiratory inflammation and infections caused by viruses and/or microbes.

Pediatric First-Degree Burn Management With Honey and 1% Silver Sulfadiazine (Ag-SD): Comparison and Contrast

Background The cardinal area of managing fire wounds is guided by adequately evaluating the burn-induced lesion's profundity and size. Superficial second-degree burns are often treated through daily reinstating with fresh sterile bandaging with appropriate topical antimicrobials to allow rapid spontaneous epithelialization. Around the world, a wide variety of substances are used to treat these wounds, from honey to synthetic biological dressings. Objective This study intended to determine honey's therapeutic potential compared with 1% silver sulfadiazine (Ag-SD) in arsenal-caused contusion medicament fulfillment. Methods A total of 70 cases were evaluated in this research work after fulfilling the required selection criteria during the study period of January 2014 to December 2014 and January 2017 to December 2017. Purposive selection criteria were adopted in the study to select research patients. The patients in Group-1 (n = 35) relied on honey as medication, while patients in Group-2 (n = 35) relied on 1% Ag-SD. Results In Group-1, exudation (68.4%) and sloughing (82.9%) were substantially reduced by Days 3 and 5 of therapeutic intervention, respectively. However, in Group-2, a reduction of exudation (17.1%) and sloughing (22.9%) occurred after Days 3 and 5 of treatment, respectively. Completion of the epithelialization process was observed among Group-1 and Group-2 cases. It was detected after Days 7 and 10 of treatment at 36.3% and 77% (Group-1) and 27% and 67% (Group-2), respectively. Around 3 ml of 1% honey was required per body surface area per dressing in Group-1. On the other hand, in Group-2, 2 gm Ag-SD was needed per body surface area per dressing. Conclusion Patients treated with honey found better clinical outcomes in managing superficial partial-thickness burns.

The role and therapeutic potential of gut microbiome in severe burn

Severe burn is a serious acute trauma that can lead to significant complications such as sepsis, multiple organ failure, and high mortality worldwide. The gut microbiome, the largest microbial reservoir in the human body, plays a significant role in this pathogenic process. Intestinal dysbiosis and disruption of the intestinal mucosal barrier are common after severe burn, leading to bacterial translocation to the bloodstream and other organs of the body, which is associated with many subsequent severe complications. The progression of some intestinal diseases can be improved by modulating the composition of gut microbiota and the levels of its metabolites, which also provides a promising direction for post-burn treatment. In this article, we summarised the studies describing changes in the gut microbiome after severe burn, as well as changes in the function of the intestinal mucosal barrier. Additionally, we presented the potential and challenges of microbial therapy, which may provide microbial therapy strategies for severe burn.

Successful prevention of secondary burn progression using infliximab hydrogel: A murine model

INTRODUCTION

Burn injury remains a serious cause of morbidity and mortality worldwide. Severity of burns is determined by the percentage of burned area compared to the body surface area, age of patient, and by the depth of skin and soft tissue involvement; these factors determine management as well as prospective outcomes. The pathophysiology of partial- to full-thickness burn conversion remains poorly understood and is associated with a worse overall prognosis. Recent studies have demonstrated that an altered inflammatory response may play a significant role in this conversion and therefore a reduction in early inflammation is crucial to ultimately decreasing burn severity and morbidity. We hypothesize that the application of a microcapillary gelatin-alginate hydrogel loaded with anti-TNF-α (infliximab) monoclonal antibodies to a partial-thickness burn will reduce inflammation within partially burned skin and prevent further progression to a full-thickness burn.

METHODS

Assembly of the microfluidic hydrogels is achieved by embedding microfibers within a hydrogel scaffold composed of a gelatin-alginate blend, which is then soaked in a solution containing anti-TNF-α antibodies for drug loading. 12 young (2-4 months) and 12 old (>16 months) mice were given partial thickness burns. The treatment cohort received the anti-TNF-α infused hydrogel with an occlusive dressing and the control cohort only received an occlusive dressing. Mice were euthanized at post-burn day 3 and skin samples were taken. Burn depth was evaluated using Vimentin immunostaining.

RESULTS

All mice in the treatment cohort demonstrated decreased conversion of burn from partial to full thickness injury (old = p < 0.01, young = p < 0.001) as compared to the control group. Old mice had greater depth of burn than young mice (p < 0.001). There were greater eosinophils in the treatment cohort for both young and old mice, but it did not reach statistical significance.

CONCLUSION

The application of a novel microcapillary gelatin-alginate hydrogel infused with anti-TNF-α antibody to partial thickness burns in mice showed reduction in partial to full thickness burn secondary progression as compared to controls using this murine model; this promising finding might help decrease the high morbidity and mortality associated with burn injuries.

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.

Risk Factors of Type 1 Leprosy Reaction in Leprosy Patients attending Leprosy Division of Dermatology and Venereology Outpatient Clinic of Dr Soetomo General Hospital in 2017–2019: A Retrospective Study

BACKGROUND: Type 1 leprosy reaction is a delayed hypersensitivity reaction caused by increased response of cellular-mediated immunity to Mycobacterium leprae. Manifestations include skin and nerve lesions, edema, and permanent disabilities. There are several risk factors that should be recognized to prevent disabilities. AIM: The aim of this study was to analyze the relationship of risk factors to the occurrence of type 1 leprosy reaction in leprosy patients treated at the Outpatient Clinic of Dr. Soetomo General Hospital. METHODS: This study was an analytical study with retrospective observational study design. Data were secondary from the medical records of leprosy patients at the Outpatient Clinic of Dr. Soetomo General Hospital from January 2017 to December 2019. RESULTS: Out of 364 patients in the Outpatient Clinic, 190 (52.2%) had leprosy without a reaction and 65 (17.9%) had type 1 reaction. Analysis showed that age, leprosy type, and treatment regimen were significantly associated with the incidence of type 1 reaction (p = 0.023; 0.003 and 0.004, respectively), with the leprosy type as the most dominant risk factor. Age 15–34 years old; leprosy types BB, BL, and BT; and the MB MDTL therapeutic regimen are risk factors for the occurrence of type I leprosy reaction. CONCLUSION: There is a statistically significant correlation between the risk factor and the occurrence of type 1 leprosy reaction in leprosy patient. The risk factor that has significant correlation is age 15–34 years; leprosy types BB, BL, and BT; and the MB MDTL therapeutic regimen. The most significant risk factor for the occurrence of type 1 leprosy reaction from our study is the type of leprosy (BB, BL, and BT).

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.

Inflammatory and coagulative pathophysiology for the management of burn patients with COVID-19: systematic review of the evidence

The pathogenesis of coronavirus disease 2019 (COVID-19) involves a prominent innate immune response to SARS-CoV-2 infection, including inflammatory cytokines, chemokines, the complement system and acute phase proteins. This hyperinflammatory response predisposes patients to thromboembolic disease, acute lung injury, acute respiratory distress syndrome and multiple organ dysfunction syndrome. In burn injuries, damaged tissues induce a local and systemic inflammatory response through pathways associated to COVID-19. As such, a COVID-19 positive patient sustaining burn injuries may have an amplified response to the burn insult due to their baseline hyperinflammatory and hypercoagulable states. Burn patients may have compromised physiological reserve to withstand the insult of surgical intervention before reaching clinical instability. The concurrent pathogenesis of COVID-19 and the inflammatory response in burn injury have serious implications on the management of burn patients.

Linking Marital Support to Aging-Related Biomarkers: Both Age and Marital Quality Matter

OBJECTIVES

Marital support is central to couples' relationships, yet support's health implications can vary widely. Guided by attribution bias and aging theories, the current study examined whether age and marital satisfaction moderate the links of perceived and received spousal support to aging-related biomarkers.

METHODS

Couples (N = 93, ages 22-77) rated marital satisfaction, overall perceived spousal support, and the quality of support received from their spouse in a lab-based discussion. Blood samples collected at baseline, immediately post-discussion, 3 hr post-discussion, and end-of-visit were assayed for proinflammatory cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-6, as well as insulin-like growth factor (IGF)-1.

RESULTS

Consistent with predictions, less satisfied older couples who received lower-quality spousal support during their discussion had greater increases in TNF-α than those who received higher-quality support; highly satisfied couples of all ages and less satisfied younger couples did not show these inflammatory changes. Highly satisfied older couples with greater perceived spousal support had lower TNF-α across the day and higher IGF-1.

DISCUSSION

Marital satisfaction and age may shape spousal support's significance for healthy aging. Rose-colored lenses worn only in the most satisfying marriages may protect couples from the possible health risks of low-quality received support and enhance potential benefits of perceived support. For better or worse, these health implications may grow with older age.

Elevated interleukin levels are associated with higher severity and mortality in COVID 19 - A systematic review, meta-analysis, and meta-regression

BACKGROUND AND AIMS

COVID 19 pneumonia commonly leads to ARDS. The occurrence of ARDS in COVID 19 patients is thought to occur secondary to an exaggerated immunologic response. In this meta-analysis, we aim to comprehensively study the various levels of immunological parameters in patients with COVID 19.

MATERIALS AND METHODS

We performed a systematic literature search from PubMed, EuropePMC, SCOPUS, Cochrane Central Database, and medRxiv with the search terms, "COVID-19" and "Interleukin". The outcome of interest was prognosis in COVID 19 patients.

RESULTS

We performed meta analysis of 16 studies. Higher counts of CD4 and CD8 with Lower Levels of TNF-a, IL2R, IL6, IL8 were observed on patients with good prognosis compared to patients with poor prognosis; -0.57 (pg/mL) (-1.10, -0.04, p = 0.04), (I2 91%, p < 0.001); -579.84 (U/mL) (-930.11, -229.57, p < 0.001), (I2 96%, p < 0.001); -1.49 (pg/mL) (-1.97, -1.01, p < 0.001), (I2 94%, p < 0.001); -0.80 (pg/mL) (-1.21, -0.40, p < 0.001), (I2 79%, p < 0.001); -2.51 (pg/mL) (-3.64, -1.38, p < 0.00001), (I2 98%, p < 0.001) respectively. Meta-regression showed age and hypertension (coefficient: 1.99, and -1.57, p = 0.005, and 0.006) significantly influenced association between IL-6 and poor outcome.

CONCLUSION

Elevated immune response to coronavirus occurs in COVID 19 patients. Higher counts of CD4 and CD8 were seen in patients with good prognosis compared to patients with poor prognosis, with Lower levels of TNF-a, IL2R, IL6, IL8, were observed in patients with good prognosis compared to patients with poor prognosis.

Sepsis Definitions in Burns

Background: Sepsis is the leading cause of death in burns. Despite its importance, sepsis lacks a proper definition. An established definition will lead to early and accurate diagnosis, prompt treatment, and a reduced mortality rate. The aim of this work is to discuss current definitions and to look ahead at novel definitions with clinical implications. Method: A review of the current understanding of sepsis definitions in burns. Results: Adaptation of sepsis definitions in the general population and specific burn definitions have gotten better but still need improvements and, potentially, incorporation of molecular, laboratory, patient-specific, and clinical factors. This work includes the history, evolution, and predictive value of current definitions of sepsis in burns. A review of current and future markers of sepsis and potentially useful definitions are presented. Conclusions: Sepsis definitions have evolved over the last decades and will continue to do so. We believe the best definition in burn patients is the Sepsis-3 that was developed originally for critically ill patients. However, there are several studies investigating more specific definitions with better sensitivity and specificity.

Mortality following combined burn and traumatic brain injuries: An analysis of the national trauma data bank of the American College of Surgeons

BACKGROUND

Severe burn and traumatic brain injuries (TBI) lead to significant mortality, and combined burn-TBI injuries may predispose towards even worse outcomes. The purpose of this study was to investigate the mortality of patients with burn, burn with non-TBI trauma, and combined burn/TBI to determine if combined injury portends a worse outcome.

METHODS

We obtained the National Trauma Data Bank from 2007 to 2012, identifying 32,334 patients with burn related injuries, dividing this cohort into three injury types: BURN ONLY, BURN with TRAUMA/NO TBI, and BURN with TBI. For each patient, demographic data was obtained, including age, gender, presence of trauma, TBI, or inhalation injury, burn total body surface area (TBSA), Glasgow Coma Scale, Injury Severity Score, and mortality. Multivariable logistic regression was performed.

RESULTS

Age, gender, and TBSA were similar across the three injury groups, but the incidence of inhalation injury was doubled in the BURN with TRAUMA/NO TBI (15.4 %) and BURN with TBI (15.3 %) groups when compared to the BURN ONLY (7.2 %) group. Mortality differed across injury categories after adjusting for age, TBSA, and inhalation injury. Increased mortality was seen in BURN with TRAUMA/NO TBI versus BURN ONLY (OR = 1.27 [1.06, 1.53]) and was higher when comparing BURN with TBI versus BURN ONLY (OR = 4.22 [2.85, 6.18]). BURN with TBI also had higher mortality when compared to BURN with TRAUMA/NO TBI (OR = 3.33 [2.30, 4.82]). The logs odds of mortality also increased with increasing age, TBSA and presence of inhalation injury.

DISCUSSION

This analysis of the NTDB suggests that mortality following burn-related injuries may be higher when burn injury is combined with TBI when compared to burns with other trauma, even after correcting for age, TBSA, and inhalation injury. Further clinical and laboratory research is needed to validate these findings and better understand how to optimize combined TBI and burn injury treatment.

Burns in the Elderly: Potential Role of Stem Cells

Burns in the elderly continue to be a challenge despite advances in burn wound care management. Elderly burn patients continue to have poor outcomes compared to the younger population. This is secondary to changes in the quality of the aged skin, leading to impaired wound healing, aggravated immunologic and inflammatory responses, and age-related comorbidities. Considering the fast-growing elderly population, it is imperative to understand the anatomic, physiologic, and molecular changes of the aging skin and the mechanisms involved in their wound healing process to prevent complications associated with burn wounds. Various studies have shown that stem cell-based therapies improve the rate and quality of wound healing and skin regeneration; however, the focus is on the younger population. In this paper, we start with an anatomical, physiological and molecular dissection of the elderly skin to understand why wound healing is delayed. We then review the potential use of stem cells in elderly burn wounds, as well as the mechanisms by which mesenchymal stem cell (MSCs)-based therapies may impact burn wound healing in the elderly. MSCs improve burn wound healing by stimulating and augmenting growth factor secretion and cell proliferation, and by modulating the impaired elderly immune response. MSCs can be used to expedite healing in superficial partial thickness burns and donor site wounds, improve graft take and prevent graft breakdown.

Post-burn temporal dynamics of blood plasma histamine during the initial 6 days from injury

BACKGROUND

Burn injuries can induce distinct, systemic inflammatory and immunological responses which occur acutely up to 72 hrs or chronically after 24 hrs. Previously published literature showed a dramatic increase in whole blood histamine values within 24 hrs of a thermal injury. However, the data is limited due to infrequent monitoring, resulting in statistically insignificant findings. The goal of this study was to determine localized histamine fluctuations for 6 consecutive days in a successive group of patients admitted immediately after a burn.

METHOD

Using blood plasma from 7 patients (average total burn surface area 24.7%), we examined histamine within an average 4.1 (± 0.3) hrs from burn injury, by means of a monoclonal-based competitive binding enzyme immunoassay. Histamine values were normalized to patient baselines prior to determining overall averages. Patient vitals and electrolyte values were extracted from the electronic health record. A two-tailed student t-test was used to compare values with p-value ≤ 0.05 considered statistically significant using statistical software R.

RESULTS

The histamine values were significantly higher than patient baseline values up to 48 hrs (p-value ≤ 0.05), followed by a return to baseline values from approximately 3 days post-injury. Heart rates were within normal values up until 72 hrs. Hematocrit and hemoglobin began within normal values, dropped at 72 hrs, and reduced significantly from 96 hrs post-injury. The electrolyte calcium began within the normal range, and then was significantly less than the baseline value from 96 hrs post-injury.

CONCLUSIONS

We have shown a distinct and significant increase in histamine plasma levels within 48 hrs after a moderate burn injury.

Genome-wide comparisons of gene expression in adult versus elderly burn patients

Purpose

Mortality and morbidity rates of elderly burn patients remain high despite numerous advancements in modern burn care. While prior studies have offered first insights on the biochemical changes in elderly burn patients compared to adults, the underlying cellular responses remain largely unknown. In this study, we aim to characterize the transcriptome of elderly burn patients and compare it to adult burn patients to obtain insights into the underlying molecular responses post-burn and to elucidate the effect of advanced age on the acute burn response.

Materials and methods

Microarray data obtained from the Glue Grant Trauma-Related Database was obtained from blood specimens for ten elderly patients (n = 10), each with a set of two sex and total body surface area (TBSA) matched adult controls (n = 20), during the acute phase post-burn. Adult and elderly demographics and clinical outcomes were contrasted using using the Chi-Square test, Fisher’s Exact Test, or two-sample t-tests, as appropriate (p<0.05). Enrichment and heat maps were generated to compare gene expression in elderly versus adult burn patients.

Results

Supervised analysis identified multiple genes that were differentially expressed between the elderly and adult groups. Pathway analysis and heatmap generation suggest that elderly patients share a distinct hypo-inflammatory response in the acute post-burn phase with downregulation of a number of immune-related pathways, including those related to antigen processing, specifically via MHC class I, ubiquitination and proteasome degradation (p<0.001, FDR < .001). Cell signalling pathways, such as NF-κB, C-type lectin receptor, and T cell receptor signalling were also significantly downregulated in elderly burn patients, as well as those relating to antiviral immunity (p<0.001, FDR < .001). Many genes which were observed to be upregulated in elderly patients with high TBSA burn injuries were associated with destruction-related cellular pathways such as complement activation and immunoglobulin production (p<0.005, FDR <0.01).

Conclusions

The altered inflammatory and immune responses at the transcriptome level in elderly patients after burn are indicative of a failure in elderly burn patients to initiate an appropriate inflammatory and stress response during the acute phase post-burn.

Acute Phase Response in Critically Ill Elderly Burn Patients

OBJECTIVES

Survival of elderly burn patients remains unacceptably poor. The acute phase, defined as the first 96 hours after burn, includes the resuscitation period and influences subsequent outcomes and survival. The aim of this study was to determine if the acute phase response post burn injury is significantly different in elderly patients compared with adult patients and to identify elements contributing to adverse outcomes.

DESIGN

Cohort study.

SETTING

Tertiary burn center.

PATIENTS

Adult (< 65 yr old) and elderly (≥ 65 yr old) patients with an acute burn injury.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We included all patients with an acute burn injury greater than or equal to 20% total body surface area to our burn center from 2011 to 2016. Clinical and laboratory measures during the acute phase were compared between adult and elderly patients. Outcomes included clinical hemodynamic measurements, organ biomarkers, volume of fluid resuscitation, cardiac agents, and the inflammatory cytokine response in plasma. Data were analyzed using the Student t test, Mann-Whitney U test, and Fisher exact test. A total of 149 patients were included, with 126 adults and 23 elderly. Injury severity was not significantly different among adult and elderly patients. Elderly had significantly lower heart rates (p < 0.05), cardiac index (p < 0.05), mean arterial pressure (p < 0.05), PaO2/FIO2 (p < 0.05), and pH (p < 0.05), along with higher lactate (p < 0.05). Organ biomarkers, particularly creatinine and blood urea nitrogen, showed distinct differences between adults and elderly (p < 0.05). Elderly had significantly lower levels of interleukin-6, monocyte chemotactic protein-1, monocyte chemotactic protein-3, and granulocyte-colony stimulating factor during the acute phase (p < 0.05). Overall mortality was significantly higher in elderly patients (5% vs 52%; p < 0.0001).

CONCLUSIONS

Response to the burn injury during the acute phase response after burn is substantially different between elderly and adult burn patients and is characterized by cardiac depression and hypoinflammation.

Increased mortality in elderly patients with acute respiratory distress syndrome is not explained by host response

Background

Advanced age is associated with increased mortality in acute respiratory distress syndrome (ARDS) patients. Preclinical studies suggest that the host response to an injurious challenge is age-dependent. In ARDS patients, we investigated whether the association between age and mortality is mediated through age-related differences in the host response.

Methods

This was a prospective longitudinal observational cohort study, performed in the ICUs of two university-affiliated hospitals. The systemic host response was characterized in three predefined age-groups, based on the age-tertiles of the studied population: young (18 to 54 years, N = 209), middle-aged (55 to 67 years, N = 213), and elderly (67 years and older, N = 196). Biomarkers of inflammation, endothelial activation, and coagulation were determined in plasma obtained at the onset of ARDS. The primary outcome was 90-day mortality. A mediation analysis was performed to examine whether age-related differences in biomarker levels serve as potential causal pathways mediating the association between age and mortality.

Results

Ninety-day mortality rates were 30% (63/209) in young, 37% (78/213) in middle-aged, and 43% (84/196) in elderly patients. Middle-aged and elderly patients had a higher risk of death compared to young patients (adjusted odds ratio, 1.5 [95% confidence interval 1.0 to 2.3] and 2.1 [1.4 to 3.4], respectively). Relative to young patients, the elderly had significantly lower systemic levels of biomarkers of inflammation and endothelial activation. Tissue plasminogen activator, a marker of coagulation, was the only biomarker that showed partial mediation (proportion of mediation, 10 [1 to 28] %).

Conclusion

Little evidence was found that the association between age and mortality in ARDS patients is mediated through age-dependent differences in host response pathways. Only tissue plasminogen activator was identified as a possible mediator of interest.

Trial registration

This trial was registered at ClinicalTrials.gov (identifier NCT01905033, date of registration July 23, 2013).

Age and Sex Influence the Hippocampal Response and Recovery Following Sepsis

Although in-hospital mortality rates for sepsis have decreased, survivors often experience lasting physical and cognitive deficits. Moreover, older adults are more vulnerable to long-term complications associated with sepsis. We employed a murine model to examine the influence of age and sex on the brain’s response and recovery following sepsis. Young (~ 4 months) and old (~ 20 months) mice (C57BL/6) of both sexes underwent cecal ligation and puncture (CLP) with restraint stress. The hippocampal transcriptome was examined in age- and sex-matched controls at 1 and 4 days post-CLP. In general, immune- and stress-related genes increased, while neuronal, synaptic, and glial genes decreased 1 day after CLP-induced sepsis. However, specific age and sex differences were observed for the initial responsiveness to sepsis as well as the rate of recovery examined on day 4. Young females exhibited a muted transcriptional response relative to young males and old females. Old females exhibited a robust shift in gene transcription on day 1, and while most genes recovered, genes linked to neurogenesis and myelination continued to be downregulated by day 4. In contrast, old males exhibited a more delayed or prolonged response to sepsis, such that neuronal and synaptic genes continued to decrease while immune response genes continued to increase on day 4. These results suggest that aging is associated with delayed recovery from sepsis, which is particularly evident in males.

Use of the burn intervention score to calculate the charges of the care of burns

BACKGROUND

To our knowledge this is the first published estimate of the charges of the care of burns in Sweden. The Linköping Burn Interventional Score has been used to calculate the charges for each burned patient since 1993. The treatment of burns is versatile, and depends on the depth and extension of the burn. This requires a flexible system to detect the actual differences in the care provided. We aimed to describe the model of burn care that we used to calculate the charges incurred during the acute phase until discharge, so it could be reproduced and applied in other burn centres, which would facilitate a future objective comparison of the expenses in burn care.

METHODS

All patients admitted with burns during the period 2010-15 were included. We analysed clinical and economic data from the daily burn scores during the acute phase of the burn until discharge from the burn centre.

RESULTS

Total median charge/patient was US$ 28 199 (10th-90th centiles 4668-197 781) for 696 patients admitted. Burns caused by hot objects and electricity resulted in the highest charges/TBSA%, while charges/day were similar for the different causes of injury. Flame burns resulted in the highest mean charges/admission, probably because they had the longest duration of stay. Mean charges/patient increased in a linear fashion among the different age groups.

CONCLUSION

Our intervention-based estimate of charges has proved to be a valid tool that is sensitive to the procedures that drive the costs of the care of burns such as large TBSA%, intensive care, and operations. The burn score system could be reproduced easily in other burn centres worldwide and facilitate the comparison regardless of the differences in the currency and the economic circumstances.

The Role of Chemokines in Wound Healing

Wound healing is a multistep process with four overlapping but distinct stages: hemostasis, inflammation, proliferation, and remodeling. An alteration at any stage may lead to the development of chronic non-healing wounds or excessive scar formation. Impaired wound healing presents a significant health and economic burden to millions of individuals worldwide, with diabetes mellitus and aging being major risk factors. Ongoing understanding of the mechanisms that underly wound healing is required for the development of new and improved therapies that increase repair. Chemokines are key regulators of the wound healing process. They are involved in the promotion and inhibition of angiogenesis and the recruitment of inflammatory cells, which release growth factors and cytokines to facilitate the wound healing process. Preclinical research studies in mice show that the administration of CCL2, CCL21, CXCL12, and a CXCR4 antagonist as well as broad-spectrum inhibition of the CC-chemokine class improve the wound healing process. The focus of this review is to highlight the contributions of chemokines during each stage of wound healing and to discuss the related molecular pathologies in complex and chronic non-healing wounds. We explore the therapeutic potential of targeting chemokines as a novel approach to overcome the debilitating effects of impaired wound healing.

NLRP3 Inflammasome Modulates Post-Burn Lipolysis and Hepatic Fat Infiltration via Fatty Acid Synthase

Burns result in generalized catabolism, lipolysis, and hyperinflammation. NLRP3 inflammasome, a mediator of hyperinflammation, is upregulated in burn patients' adipose tissue within 7 days post-burn. However, its role during the acute phase is unknown. Here, wild-type (WT) and NLRP3 knockout (NLRP3^-/-) mice were exposed to 25% TBSA scald burn. Flow cytometric analysis demonstrated greater liver macrophage infiltration in NLRP3^-/- yet decreased protein expression of NLRP3 components, ER stress, and apoptosis. NLRP3^-/- had increased circulating free fatty acids (FFA), fatty deposition and liver weight 1 hour post-burn. Alterations in adipose fatty acid synthase (Fasn) expression affects FFA levels post-burn; WT have an early peak in Fasn gene and protein expression that is lost in NLRP3^-/-, resulting in increased lipolysis and hepatic fatty deposition. In summary, our findings reveal that NLRP3 inflammasome activation is a double-edged sword. While prolonged inflammation and long-term effects of macrophage activation are associated with poor outcomes, acute inflammation may be beneficial. These results highlight the important metabolic role that NLRP3 inflammasome plays in the acute phase, ultimately affecting survival post-burn.

The time-course of the inflammatory response to major burn injury and its relation to organ failure and outcome

Burn injury causes major inflammatory activation and cytokine release, however, the temporal resolution of the acute and sub-acute inflammatory response has not yet been fully delineated. To this end, we have quantified 20 inflammatory mediators in plasma from 44 adult patients 0-21 days after burn injury and related the time course of these mediators to % total body surface area (TBSA) burned, clinical parameters, organ failure and outcome. Of the cytokines analyzed in these patients, interleukin 6 (IL-6), IL-8, IL-10 and monocyte chemoattractant protein 1 (MCP-1) correlated to the size of the injury at 24-48h after burn injury. In our study, the concentration of IL-10 had prognostic value in patients with burn injury both measured at admission and at 24-48h after injury. However, simple demographic data such as age, % burned TBSA, inhalation injury and their combination, the Baux score and modified Baux score, outperform most of the cytokines, with the exception of IL-8 and MCP-1 levels on admission, in predicting death.

Risk of pneumonia in patients with burn injury: a population-based cohort study

Background

Burns are the main cause of accidental injury, and pneumonia is a common respiratory disease in humans.

Aim

The purpose of this study was to investigate the relationship between burn injury and pneumonia.

Patients and methods

A nationwide population-based cohort study was conducted using data from the National Health Insurance Research Database in Taiwan. We identified and enrolled 2,893 subjects with burn injury, who were individually matched to 2,893 subjects in the comparison group by using the propensity score. Furthermore, we used a self-controlled case-series design to estimate the temporal association between burn injury and pneumonia.

Results

Exposure to burn injury revealed a higher risk of pneumonia than that to non-burn injury within 1 year. The Cox proportional hazards model revealed that, compared with the non-burn injury, burn injury yielded a 2.39-fold (95% CI=1.44-3.96) increase in risk of pneumonia. The exposure period of burn injury within 30 days showed 2.76-fold increase in risk of pneumonia (95% CI=1.44-3.96) compared with that in the baseline period.

Conclusion

Burn injury was associated with a significant increased risk of pneumonia, especially occurring within 30 days.

Predictors of Early Onset Multiple Organ Dysfunction in Major Burn Patients with Ventilator Support: Experience from A Mass Casualty Explosion

Organ dysfunction is common in patients with major burns and associated with poor outcomes. The risk factors for early onset multiple organ dysfunction syndrome (MODS) in major burn patients with invasive ventilator support has rarely been evaluated before. In this study, major burn patients with invasive ventilator support from 499 victims suffered in a mass casualty color dust explosion were retrospectively enrolled. The development of early MODS that occurred within 5 days after burn injury was determined and the risk factors associated with early MODS were analyzed. A total of 88 patients from five medical centers were included. Their mean total body surface area (TBSA) was 60.9 ± 15.8%, and 45 (51.1%) patients had early MODS. Hematologic failure was the most common organ failure (68.6%), followed by respiratory failure (48.9%). Independent clinical factors associated with early MODS included TBSA ≥55% (OR: 3.83; 95% CI: 1.29-11.37) and serum albumin level <2.1 g/dL upon admission (OR: 3.43; 95% CI: 1.01-11.57). Patients with early MODS had prolonged ventilator dependence and longer ICU admission than those without early MODS. Our results showed that early MODS in major burn patients with invasive ventilator support is very common and can be predicted early on admission.

Accumulation of myeloid lineage cells is mapping out liver fibrosis post injury: a targetable lesion using Ketanserin

Liver fibrosis is problematic after persistent injury. However, little is known about its response to an acute insult. Accumulation of myeloid lineage cells contributes into the promotion and resolution of inflammation and fibrosis. Using Cre-transgenic mice that specifically mark myeloid lineage cells with EYFP and burn as a model of acute systemic injury, we investigated the role of myeloid lineage cells in the liver after acute injury. Our data show that thermal injury in mice (30% total body surface area) induces fibrosis predominantly around portal venules whereas myeloid cells are enriched throughout the liver. The fibrosis peaks around 1-2 weeks post injury and resolves by week 3. Ablating myeloid cells led to lower fibrosis. Through FACS sorting, we isolated myeloid lineage cells (EYFP +ve cells) from injured animals and from the control uninjured animals and subjected the extracted RNA from these cells to microarray analysis. Microarray analysis revealed an inflammatory signature for EYFP +ve cells isolated from injured animals in comparison with control cells. Moreover, it showed modulation of components of the serotonin (5-HT) pathway in myeloid cells. Antagonizing the 5HT2A/2C receptor decreased fibrosis in thermally injured mice by skewing macrophages away from their pro-fibrotic phenotype. Macrophages conditioned with Ketanserin showed a lower pro-fibrotic phenotype in a co-culture system with mesenchymal cells. There is a spatiotemporal pattern in liver fibrosis post-thermal injury, which is associated with the influx of myeloid cells. Treating mice with a 5HT2A/2C receptor antagonist promotes an anti-fibrotic effect, through modulating the phenotype of macrophages.

Burn wounds in the young versus the aged patient display differential immunological responses

BACKGROUND

Individuals in the geriatric age range are more prone than younger individuals to convert their partial thickness thermal burns into full thickness injuries. We hypothesized that this often observed clinical phenomenon is strongly related to differential local injury responses mediated by the immune system.

MATERIALS & METHODS

Skin samples from areas with partial thickness thermal burns were obtained during routine excision and grafting procedures between post burn days 2-6. Tissue samples were grouped by age ranges with young patients defined as <30 years of age or aged patients defined as >65. Formalin fixed samples were used to confirm depth of burn injury and companion sections were homogenized for multiplex analysis using a Luminex platform. Immunohistochemical staining was used to quantify total macrophage numbers as well as the M1 and M2 subpopulations.

RESULTS

Our analysis includes samples derived from 11 young subjects (mean age=23) and 3 aged subjects (mean age=79.2). Our initial survey of analytes examined 31 cytokines/chemokines. Twelve were excluded from consideration as they were present in concentrations either above or below the optimal detection range. Two analytes emerged as candidate molecules with significant differences between the young and the aged patient responses to burn injury. EGF levels were on average 21.69pg/ml in young vs 14.87pg/ml in aged (p=0.032). RANTES/CCL5 levels were on average 14.86pg/ml in young vs 4.26pg/ml in aged (p=0.026). Elevated macrophage numbers were present within wounds of younger patients compared to the old (p<0.01), with a higher concentration of the M1 type in the elderly (p>0.05).

CONCLUSION

Our study has identified at least 2 well known cytokines, CCL5 (RANTES) and EGF, which are differentially regulated in response to burn injury by young versus aged burn victims. Evidence suggests that a proinflammatory environment can explain the high conversion rate from partial to full thickness burns. Our data suggest the need for future studies at the point of injury (cutaneous targets) that may be modulated by post burn release of cytokines/chemokines.

Tunable sequential drug delivery system based on chitosan/hyaluronic acid hydrogels and PLGA microspheres for management of non-healing infected wounds

Treatment of non-healing infected wounds is an arduous task in clinical practice. Early antibacterial strategy and subsequent promotion of granulation tissue growth facilitate to cure the wounds. For this purpose, we fabricated a sequential drug delivery system by incorporation of an injectable hydrogel with porous PLGA microspheres. Vancomycin was linked to the injectable hydrogel via the reversible Schiff's base reaction, and VEGF were encapsulated into PLGA microspheres. After adding vancomycin, the strength and elasticity of the hydrogel were improved, and the gelation time was shortened. The results also demonstrated that the releasing profile of vancomycin was pH-dependent and the VEGF's profile was adjustable by changing the pore sizes of PLGA microspheres. The duration of VEGF release was longer than vancomycin. This hybrid system was valid to inhibit bacteria growth and accelerate vein endothelial cell proliferation in vitro. In rat models, it was effective to manage non-healing infected wounds by reducing inflammation and promoting angiogenesis. In conclusion, this sequential delivery system is promoting to manage non-healing infected wounds, and also provides a new thought to realize the staged drug release.

Status and Challenges of Predicting and Diagnosing Sepsis in Burn Patients

Burns are a common form of trauma that account for more than 300,000 deaths each year worldwide. Survival rates have improved over the past decades because of improvements in nutritional and fluid support, burn wound care, and infection control practices. Death, however, remains unacceptably high. The primary cause of death has changed over the last decades from anoxic causes to now predominantly infections and sepsis. Sepsis and septic complications are not only major contributors to poor outcomes, but they further result in longer hospital stay and higher healthcare costs. Despite the importance of infections and sepsis, the diagnosis and prediction remain a major challenge. To date, no clear diagnostic criteria or predictive formula exist that can predict reliably the occurrence of sepsis and infections. This review will highlight and discuss current definitions and criteria for diagnosis as well as predictive biomarkers of sepsis in patients with burns. It will also present the diagnostic tools employed, such as procalcitonin, C-reactive protein, and cytokines. We will discuss the benefits and shortcomings of different treatment modalities in the context of sepsis prevention. Last, we identify new therapeutic strategies for sepsis prediction and present future considerations to prevent sepsis in patients with burns. Minimizing and preventing septic complications through early detection would significantly benefit patients and necessitate continued research to unravel new biomarkers and mechanisms. Subsequent studies need to take a fresh perspective and consider the implementation of patient-centered therapeutic strategies.

Co-administration of vancomycin and piperacillin-tazobactam is associated with increased renal dysfunction in adult and pediatric burn patients

Background

Burn patients are prone to infections which often necessitate broad antibiotic coverage. Vancomycin is a common antibiotic after burn injury and is administered alone (V), or in combination with imipenem-cilastin (V/IC) or piperacillin-tazobactam (V/PT). Sparse reports indicate that the combination V/PT is associated with increased renal dysfunction. The purpose of this study was to evaluate the short-term impact of the three antibiotic administration types on renal dysfunction.

Methods

All pediatric and adult patients admitted to our centers between 2004 and 2016 with a burn injury were included in this retrospective review if they met the criteria of exposition to either V, V/IC, or V/PT for at least 48 h, had normal baseline creatinine, and no pre-existing renal dysfunction. Creatinine was monitored for 7 days after initial exposure; the absolute and relative increase was calculated, and patient renal outcomes were classified according to the Kidney Disease Improving Global Outcomes (KDIGO) criteria depending on creatinine increases and estimated creatinine clearance. Secondary endpoints (demographic and clinical data, incidences of septicemia, and renal replacement therapy) were analyzed. Antibiotic doses were modeled in logistic and linear multivariable regression models to predict categorical KDIGO events and relative creatinine increase.

Results

Out of 1449 patients who were screened, 718 met the inclusion criteria, 246 were adults, and 472 were children. Between the study cohorts V, V/IC, and V/PT, patient characteristics at admission were comparable. V/PT administration was associated with a statistically higher serum creatinine, and lower creatinine clearance compared to patients receiving V alone or V/IC in adults and children after burn injury. The incidence of KDIGO stages 1, 2, and 3 was higher after V/PT treatment. In children, the incidence of KDIGO stage 3 following administration of V/PT was greater than after V/IC. In adults, the incidence of renal replacement therapy was higher after V/PT compared with V or V/IC. Multivariate modeling demonstrated that V/PT is an independent predictor of renal dysfunction.

Conclusion

Co-administration of vancomycin and piperacillin-tazobactam is associated with increased renal dysfunction in pediatric and adult burn patients when compared to vancomycin alone or vancomycin plus imipenem-cilastin. The mechanism of this increased nephrotoxicity remains elusive and warrants further scientific evaluation.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1899-3) contains supplementary material, which is available to authorized users.

Relation between dynamic changes of platelet counts and 30-day mortality in severely burned patients

Thrombocytopenia is a common event in severely burned patients and associated with adverse outcome. The underlying relationship between the dynamic changes of platelet counts and mortality has not been well defined. We performed a 6-year retrospective chart of adult patients with a burn index of 50 or greater admitted to two burn centers and collected data on patient demographics, laboratory results, and patient outcomes. The mean daily increase in the platelet count (∆PC/∆t) from day 3 to day 10 was calculated, and 30-day mortality was determined. For the study, 141 survivors and 65 nonsurvivors were enrolled. The sequential changes in PCs presented a biphasic pattern after admission, with a slump to the nadir during the first 3 days and a subsequent recovery. With respect to 30-day mortality, compared with the AUC of APACHE-Ⅱ score (0.841), no significant difference was noted between ΔPC/ΔT and APACHE-Ⅱ score (p = 0.0648). The ΔPC/ΔT associated with the best discrimination between survivors and nonsurvivors was 20.57 × 10⁹/L due to the cutoff with optimal Youden index (0.453). By multiple logistic regression, ΔPC/ΔT ＜ 20.57 × 10⁹/L was one of the prognostic predictors of 30-day mortality. Furthermore, Kaplan-Meier estimates of hospital survival according to the size of ΔPC/ΔT revealed that a blunted increase with ΔPC/ΔT ＜ 20.57 × 10⁹/L was associated with increased 30-day mortality. A blunted daily increase in PCs, especially ΔPC/ΔT < 20.57 × 10⁹/L, is associated with increased 30-day mortality, which provides prognostic information for mortality risk assessment in severely burned patients.

Septic predictor index: A novel platform to identify thermally injured patients susceptible to sepsis

BACKGROUND

During the past decades' sepsis has become the major cause of death in severely burned patients. Despite the importance of burn sepsis, its diagnosis, let alone its prediction, is difficult if not impossible. Recently, we have demonstrated burn patients have increased NLRP3 inflammasome activation in white adipose tissue. We aimed to delineate a unique immune profile that can be used to identify septic outcomes in severely burned patients.

METHODS

Adult burn patients (n = 37) admitted to our burn center between June 2013-2015 were enrolled in this study. White adipose tissue from the site of injury and plasma were collected from severely burned patients (>20% total body surface area) within 96 hours after thermal injury, indiscriminate of sex or age.

RESULTS

We found that patients exhibiting aberrantly high levels of proinflammatory interleukin-1β and decreased macrophages at the site of injury are highly susceptible to development of sepsis. Septic patients also had increased anti-inflammatory (interleukin-10, interleukin-1RA) cytokines in plasma. The Septic Predictor Index was generated as a quotient for the site of injury macrophage proportion and interleukin-1β production. All patients who eventually develop sepsis had septic predictor index values >0.5. Septic patients with Septic Predictor Index values >1 all had sepsis onset within 12 days post-injury, whereas patients with Septic Predictor Index values between 0.5-1 all had later onset (>12 days).

CONCLUSION

The Septic Predictor Index can determine sepsis onset accurately in thermally injured patients a priori and further enables surgeons to develop clinical studies and focused therapies specifically designed for septic cohorts.

Programmed Cell Death-1/Programmed Death-ligand 1 Pathway: A New Target for Sepsis

OBJECTIVE

Sepsis remains a leading cause of death in many Intensive Care Units worldwide. Immunosuppression has been a primary focus of sepsis research as a key pathophysiological mechanism. Given the important role of the negative costimulatory molecules programmed cell death-1 (PD-1) and programmed death-ligand 1 (PD-L1) in the occurrence of immunosuppression during sepsis, we reviewed literatures related to the PD-1/PD-L1 pathway to examine its potential as a new target for sepsis treatment.

DATA SOURCES

Studies of the association between PD-1/PD-L1 and sepsis published up to January 31, 2017, were obtained by searching the PubMed database.

STUDY SELECTION

English language studies, including those based on animal models, clinical research, and reviews, with data related to PD-1/PD-L1 and sepsis, were evaluated.

RESULTS

Immunomodulatory therapeutics could reverse the deactivation of immune cells caused by sepsis and restore immune cell activation and function. Blockade of the PD-1/PD-L1 pathway could reduce the exhaustion of T-cells and enhance the proliferation and activation of T-cells.

CONCLUSIONS

The anti-PD-1/PD-L1 pathway shows promise as a new target for sepsis treatment. This review provides a basis for clinical trials and future studies aimed at revaluating the efficacy and safety of this targeted approach.

Systemic and Local Management of Burn Wounds

Management of severe burn injury (SBI) requires prompt, complex, and aggressive care. Despite major advances in the management of SBI-including patient-targeted resuscitation, management of inhalation injuries, specific nutritional support, enhanced wound therapy, and infection control-the consequences of SBI often result in complex, multiorgan metabolic changes. Consensus guidelines and clinical evidence regarding specific management of small animal burn patients are lacking. This article aims to review updated therapeutic consideration for the systemic and local management of SBI that are proven effective to optimize outcomes in human burn patients and may translate to small animal patients.

Untangling glycaemia and mortality in critical care

Background

Hyperglycaemia is associated with adverse outcomes in the intensive care unit, and initial studies suggested outcome benefits of glycaemic control (GC). However, subsequent studies often failed to replicate these results, and they were often unable to achieve consistent, safe control, raising questions about the benefit or harm of GC as well as the nature of the association of glycaemia with mortality and clinical outcomes. In this study, we evaluated if non-survivors are harder to control than survivors and determined if glycaemic outcome is a function of patient condition and eventual outcome or of the glycaemic control provided.

Methods

Clinically validated, model-based, hour-to-hour insulin sensitivity (SI) and its hour-to-hour variability (%ΔSI) were identified over the first 72 h of therapy in 145 patients (119 survivors, 26 non-survivors). In hypothesis testing, we compared distributions of SI and %ΔSI in 6-hourly blocks for survivors and non-survivors. In equivalence testing, we assessed if differences in these distributions, based on blood glucose measurement error, were clinically significant.

Results

SI level was never equivalent between survivors and non-survivors (95% CI of percentage difference in medians outside ±12%). Non-survivors had higher SI, ranging from 9% to 47% higher overall in 6-h blocks, and this difference became statistically significant as glycaemic control progressed. %ΔSI was equivalent between survivors and non-survivors for all 6-hourly blocks (95% CI of difference in medians within ±12%) and decreased in general over time as glycaemic control progressed.

Conclusions

Whereas non-survivors had higher SI levels, variability was equivalent to that of survivors over the first 72 h. These results indicate survivors and non-survivors are equally controllable, given an effective glycaemic control protocol, suggesting that glycaemia level and variability, and thus the association between glycaemia and outcome, are essentially determined by the control provided rather than by underlying patient or metabolic condition.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1725-y) contains supplementary material, which is available to authorized users.

Lipidomic analysis enables prediction of clinical outcomes in burn patients

Recent discoveries have highlighted the novel metabolic functions of adipose tissue in enhancing hypermetabolism after trauma. As the exact function and expression profiles of serum lipids and free fatty acids (FFA) are essentially unknown, we determined the lipidomic expression profile after burn in correlation to clinical outcomes to identify important lipid mediators affecting post-burn outcomes. We conducted a prospective cohort study with 46 adult burn patients and 5 healthy controls at the Ross Tilley Burn Center in Toronto, Canada. Patients were stratified based on major demographic and clinical variables, including age, burn severity, mortality, and sepsis. Serum FFAs and inflammatory markers were measured during acute hospital stay. We found that FFAs were acutely elevated post-burn and returned to baseline over time. Greater burn severity and age were associated with an impaired acute response in unsaturated FFAs and pro-inflammatory cytokines. Elevations in saturated and mono-unsaturated FFAs correlated significantly to increased mortality. In summary, persistent elevation of unsaturated lipids was associated with a functionally altered inflammatory-immunological milieu and worse clinical outcomes. The present lipidomic analysis indicates profound alterations in the lipid profile after burn by characterizing key lipids as potential diagnostic and outcome indicators in critically injured patients.

IL-15 Superagonist Expands mCD8+ T, NK and NKT Cells after Burn Injury but Fails to Improve Outcome during Burn Wound Infection

Background

Severely burned patients are highly susceptible to opportunistic infections and sepsis, owing to the loss of the protective skin barrier and immunological dysfunction. Interleukin-15 (IL-15) belongs to the IL-2 family of common gamma chain cytokines and stimulates the proliferation and activation of T (specifically memory CD8), NK and NKT cells. It has been shown to preserve T cell function and improve survival during cecal ligation and puncture (CLP)-induced sepsis in mice. However, the therapeutic efficacy of IL-15 or IL-15 superagonist (SA) during infection after burn injury has not been evaluated. Moreover, very few, if any, studies have examined, in detail, the effect of burn injury and infection on the adaptive immune system. Thus, we examined the effect of burn and sepsis on adaptive immune cell populations and the effect of IL-15 SA treatment on the host response to infection.

Methods

Mice were subjected to a 35% total body surface area burn, followed by wound infection with Pseudomonas aeruginosa. In some experiments, IL-15 SA was administered after burn injury, but before infection. Leukocytes in spleen, liver and peritoneal cavity were characterized using flow cytometry. Bacterial clearance, organ injury and survival were also assessed.

Results

Burn wound infection led to a significant decline in total white blood cell and lymphocyte counts and induced organ injury and sepsis. Burn injury caused decline in CD4⁺ and CD8⁺ T cells in the spleen, which was worsened by infection. IL-15 treatment inhibited this decline and significantly increased cell numbers and activation, as determined by CD69 expression, of CD4⁺, CD8⁺, B, NK and NKT cells in the spleen and liver after burn injury. However, IL-15 SA treatment failed to prevent burn wound sepsis-induced loss of CD4⁺, CD8⁺, B, NK and NKT cells and failed to improve bacterial clearance and survival.

Conclusion

Cutaneous burn injury and infection cause significant adaptive immune dysfunction. IL-15 SA does not augment host resistance to burn wound sepsis in mice despite inducing proliferation and activation of lymphocyte subsets.