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Although use of thromboelastography (TEG) to diagnose coagulopathy and guide clinical decision-making is increasing, relative performance of different TEG methods has not been well-defined. Rapid-TEG (rTEG), kaolin-TEG (kTEG), and native-TEG (nTEG) were performed on blood samples from burn patients presenting to a regional center from admission to 21 days. Patients were categorized by burn severity, mortality, and fibrinolytic phenotypes (Shutdown [SD], Physiologic [PHYS], and Hyperfibrinolytic [HF]). Manufacturer ranges and published TEG cutoffs were examined. Concordance correlations (Rc) of TEG parameters (R, α-angle, maximum amplitude [MA], LY30) measured agreement and Cohen's Kappa (κ) determined interclass reliability. Patients (n = 121) were mostly male (n = 84; 69.4%), with median age 40 years, median TBSA burn 13%, and mortality 17% (n = 21). Severe burns (≥40% TBSA) were associated with lower admission α-angle for rTEG (P =.03) and lower MA for rTEG (P =.02) and kTEG (P =.01). MA was lower in patients who died (nTEG, P =.04; kTEG, P =.02; rTEG, P =.003). Admission HF was associated with increased mortality (OR, 10.45; 95% CI, 2.54–43.31, P =.001) on rTEG only. Delayed SD was associated with mortality using rTEG and nTEG (OR 9.46; 95% CI, 1.96–45.73; P =.005 and OR, 6.91; 95% CI, 1.35–35.48; P =.02). Admission TEGs showed poor agreement on R-time (Rc, 0.00–0.56) and α-angle (0.40 to 0.55), and moderate agreement on MA (0.67–0.81) and LY30 (0.72–0.93). Interclass reliability was lowest for R-time (κ, −0.07 to 0.01) and α-angle (−0.06 to 0.17) and highest for MA (0.22-0.51) and LY30 (0.29-0.49). Choice of TEG method may impact clinical decision-making. rTEG appeared most sensitive in parameter-specific associations with injury severity, abnormal fibrinolysis, and mortality. [ABSTRACT FROM AUTHOR]

Inhalation injury is a significant cause of morbidity and mortality in the burn patient population. However, the pathogenesis of inhalation injury and its potential involvement in burn shock is not well understood. Preclinical studies have shown endothelial injury, as measured by syndecan-1 (SDC-1) levels, to be involved in the increased vascular permeability seen in shock states. Furthermore, the lung has been identified as a site of significant SDC-1 shedding. Here we aim to characterize the contribution of endotheliopathy caused by inhalation alone in a swine model. When comparing injured animals, the fold change of circulating SDC-1 levels from preinjury was significantly higher at 2, 4, and 6 hours postinjury (P =.0045, P =.0017, and P <.001, respectively). When comparing control animals, the fold change of SDC-1 from preinjury was not significant at any timepoint. When comparing injured animals versus controls, the fold change of SDC-1 injured animals was significantly greater at 2, 4, 6, and 18 hours (P =.004, P =.03, P <.001, and P =.03, respectively). Histological sections showed higher lung injury severity compared to control uninjured lungs (0.56 vs 0.38, P <.001). This novel animal model shows significant increases in SDC-1 levels that provide evidence for the connection between smoke inhalation injury and endothelial injury. Further understanding of the mechanisms underlying inhalation injury and its contribution to shock physiology may aid in development of early, more targeted therapies. [ABSTRACT FROM AUTHOR]

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

Burn injury is associated with endothelial dysfunction and coagulopathy and concomitant inhalation injury (IHI) increases morbidity and mortality. The aim of this work is to identify associations between IHI, coagulation homeostasis, vascular endothelium, and clinical outcomes in burn patients. One hundred and twelve patients presenting to a regional burn center were included in this retrospective cohort study. Whole blood was collected at set intervals from admission through 24 hours and underwent viscoelastic assay with rapid thromboelastography (rTEG). Syndecan-1 (SDC-1) on admission was quantified by ELISA. Patients were grouped by the presence (n = 28) or absence (n = 84) of concomitant IHI and rTEG parameters, fibrinolytic phenotypes, SDC-1, and clinical outcomes were compared. Of the 112 thermally injured patients, 28 (25%) had IHI. Most patients were male (68.8%) with a median age of 40 (interquartile range, 29-57) years. Patients with IHI had higher overall mortality (42.68% vs 8.3%; P < .0001). rTEG LY30 was lower in patients with IHI at hours 4 and 12 (P < .05). There was a pattern of increased abnormal fibrinolytic phenotypes among IHI patients. There was a greater proportion of IHI patients with endotheliopathy (SDC-1 > 34 ng/ml) (64.7% vs 26.4%; P = .008). There was a pattern of increased mortality among patients with IHI and endotheliopathy (0% vs 72.7%; P = .004). Significant differences between patients with and without IHI were found in measures assessing fibrinolytic potential and endotheliopathy. Mortality was associated with abnormal fibrinolysis, endotheliopathy, and IHI. However, the extent to which IHI-associated dysfunction is independent of TBSA burn size remains to be elucidated. [ABSTRACT FROM AUTHOR]

Objective: Burn-injured patients are highly susceptible to infectious complications, which are often associated with increased morbidity and mortality. Rates of antibiotic resistance have increased, and resistant species such as methicillin-resistant Staphylococcus aureus provide additional challenges in the form of virulence factors. Proteins can disrupt local healing, leading to systemic immune disruption. To optimize outcomes, treatments that reduce pathogenicity must be identified. This study aims to compare a glycylcycline antibiotic--tigecycline--with clindamycin for effectiveness in treating superantigenic methicillin-resistant Staphylococcus aureus in burn wounds. Methods: Sprague-Dawley rats received paired 2 × 2-cm burn wounds, which were subsequently inoculated with known virulence factor-producing methicillin-resistant Staphylococcus aureus or media alone on postinjury day 1. Infected animals received twice-daily tigecycline (high or low dose), twice-daily clindamycin (high or low dose), or saline alone (positive controls). Daily sampling and imaging assessments were performed. Results: Bacterial counts and toxin levels were reduced significantly in antibiotic-treated groups relative to positive controls (P < .001). Results from day 7 showed measurable toxin levels in clindamycin-treated, but not tigecycline-treated, wounds. Imaging analysis revealed a return of wound perfusion in tigecycline-treated animals similar to the sham animals. Transcript analysis using polymerase chain reaction and polymerase chain reaction arrays demonstrated downregulation of gene expression in antibiotic-treated animals as compared with positive controls. Conclusions: Overall, this study supports the use of tigecycline in the treatment of methicillin-resistant Staphylococcus aureus-infected burn wounds. While both protein synthesis inhibitors are effective, tigecycline appears to be superior in controlling toxin levels, enabling better wound healing. [ABSTRACT FROM AUTHOR]

Introduction Burn injuries are associated with high morbidity and mortality. Burn care has improved significantly in the last few decades with emphasis on early surgical management, improvements in local wound care, and specialized critical care. While survival rates are improving, mortality remains high in certain patient populations, including those with larger burns. Burn injury induces a systemic hyperinflammatory response with detrimental side effects. Prior studies have offered early insights into the biochemical changes that occur after severe burn injury. The underlying cellular response is still largely unknown. The goal of this work is to characterize the blood transcriptome of severe burn injury and compare this response between patients who live or subsequently die of their injuries. Methods Burn patients presenting to a regional center between 2012–2017 were prospectively enrolled. Blood was collected on admission and at predetermined timepoints (Hours 2, 4, 8, 12, 24) over the first 24 hours. mRNA was isolated and a transcriptomic microarray was used to measure global transcript levels over time. To identify differentially regulated genes (FDR≤0.1) by injury severity, patients were grouped by burn size (TBSA >20%) and mortality. Microarray data was analyzed using bioinformatics software and pathway analysis. Descriptive statistics were generated with Mann-Whitney, Chi-Square, and Fisher's exact test as appropriate. Results Sixty-eight patients were included in this analysis, most patients were male with a median age of 41 (IQR, 30.5–58.5) years, and TBSA of 20% (IQR, 11–34%). Thirty-five patients suffered %TBSA injury >20%, and this group experienced greater mortality (26% vs. 3%, p=0.008). There were no significant differences in age, race, or gender. Comparative analysis of genes from patients with < />20% TBSA revealed 1250, 444, 209, 20, 865, and 557 differentially regulated genes at hours 0, 2, 4, 8, 12 and 24 respectively. Pathway analysis reveals an initial upregulation in several immune/inflammatory pathways within the >20% TBSA groups between hours 0–2 followed by shutdown between hours 12–24. Immune pathways include Th17 activation pathway and natural killer cell signaling, inflammatory pathways include EIF2 signaling. These pathways remain upregulated in the group of patients with >20% TBSA who died. Conclusions Severe burn injury is associated with an early proinflammatory immune response followed by shutdown of these pathways. Burn patients who die show continued upregulation in the first 24 hours after injury in several proinflammatory pathways compared to those who live. [ABSTRACT FROM AUTHOR]

Introduction The contribution of endothelial injury to the pathogenesis of burn shock is not well characterized. Human umbilical endothelial cells (HUVECs) have been used to study endotheliopathy in myriad shock states. This work investigates the impact of burn patient plasma on the vascular endothelium and its barrier function. Methods HUVECs were seeded into the apical chambers of transwell plates and cultured over 5–7 days to a confluent monolayer which was confirmed by a transendothelial electrical resistance (TEER) of ≥30Ω. After IRB approval, plasma was collected from burn-injured patients 4 hours after admission. Demographic and injury characteristics were collected from the medical record. Plasma Syndecan-1 (SDC-1) was quantified by ELISA. HUVEC monolayers were exposed to 10% multi-donor pooled healthy human plasma (HHP) or burn patient plasma. Monolayers were subsequently incubated with FIT-C Dextran (40,000 kD). FIT-C diffusion through monolayers was measured in basal chamber supernatants. Monolayer permeability was measured with indices calculated by normalizing values to blank (transwell inserts) and HHP-treated monolayer FIT-C diffusion. HUVECs were also cultured on glass slides and exposed to HHP or burn patient plasma. Cells were fixed with 4% Paraformaldehyde and F-Actin was stained with Texas Red-Phalloidin. Intercellular gap area was calculated using imaging software. Differences between treatment conditions were analyzed with Welch's t-test and one-way ANOVA, simple linear regression was used to characterize the relationship between plasma SDC-1 and permeability indices, significance was set at p < 0.05. Results Eight burn patient plasma samples were tested. Patients were mostly male (75%) with a mean age of 50±20 years and mean %TBSA burn of 37±34%. Five burn plasma samples significantly increased monolayer permeability. There were no significant differences between patient samples that increased permeability in age, TBSA, gender, or in-hospital mortality. Monolayer permeability indices increased between 7–15% (p< 0.05) among burn plasma treatment conditions (n=6) that increased permeability. There was a strong relationship between monolayer permeability index (%) and plasma SDC-1 (µg/mL) (p=0.03, R2=0.93). Morphological F-actin rearrangement was apparent on microscopy and intercellular gap area was increased in burn plasma treatment conditions (12% vs. 49%, p≤0.0007, n=6). Conclusions Plasma from burn patients induces endothelial damage that increases endothelial cell monolayer permeability. The endothelial biomarker SDC-1 is a reliable indicator of endothelial damage. F-actin rearrangement and an increase in intercellular gap area likely contributes to burn endotheliopathy. [ABSTRACT FROM AUTHOR]

Introduction The development of methods that generate individualized assessments of the procoagulant potential of burn patients could improve their treatment. Beyond its role as an essential intermediate in the formation of thrombin, factor (F)Xa has systemic effects as an agonist to inflammatory processes. In this study, we use a computational model to study the FXa dynamics underlying tissue factor-initiated thrombin generation in a small cohort of burn patients. Materials and Methods Plasma samples were collected upon admission (Hour 0) from nine subjects (five non-survivors) with major burn injuries and then at 48 hours. Coagulation factor concentrations (II, V, VII, VIII, IX, X, TFPI, antithrombin (AT), protein C (PC)) were measured and used in a computational model to generate time course profiles for thrombin (IIa), FXa, extrinsic tenase , intrinsic tenase and prothrombinase complexes upon a 5 pM tissue factor stimulus in the presence of 1 nM thrombomodulin. Parameters were extracted from the thrombin and FXa profiles (including max rate (MaxRIIa and MaxRFXa) and peak level (MaxLIIa and MaxLFXa)). Procoagulant potential was also evaluated by determining the concentration of the complexes at select times. Parameter values were compared between survivors and non-survivors in the burn cohort and between the burn cohort and a simulation based on the mean physiological (100%) concentration for all factor levels. Results Burn patients differed at Hour 0 (p < 0.05) from 100% mean physiological levels for all coagulation factor levels except FV and FVII. The concentration of FX, FII, TFPI, AT and PC was lower; FIX and FVIII were increased. The composition differences resulted in all nine burn patients at Hour 0 displaying a procoagulant phenotype relative to 100% mean physiological simulation (MaxLIIa (306 ± 90 nM vs. 52 nM), MaxRIIa (2.9 ± 1.1 nM/s vs. 0.3 nM/s), respectively p < 0.001); MaxRFXa and MaxLFXa were also an order of magnitude greater than 100% mean physiological simulation (p < 0.001). When grouped by survival status and compared at the time of admission, non-survivors had lower PC levels (56 ± 18% vs. 82 ± 9%, p < 0.05), and faster MaxRFXa (29 ± 6 pM/s vs. 18 ± 6 pM/s, p < 0.05) than those that survived; similar trends were observed for all other procoagulant parameters. At 48 hours when comparing non-survivors to survivors, TFPI levels were higher (108 ± 18% vs. 59 ± 18%, p < 0.05), and MaxRIIa (1.5 ± 1.4 nM/s vs. 3.6 ± 0.7 nM/s, p < 0.05) and MaxRFXa (13 ± 12 pM/s vs. 35 ± 4 pM/s, p < 0.05) were lower; similar trends were observed with all other procoagulant parameters. Overall, between admission and 48 hours, procoagulant potential, as represented by MaxR and MaxL parameters for thrombin and FXa, in non-survivors decreased while in survivors they increased (p < 0.05). In patients that survived, there was a positive correlation between FX levels and MaxLFXa (r = 0.96) and reversed in mortality (r = −0.91). Conclusions Thrombin and FXa generation are increased in burn patients at admission compared to mean physiological simulations. Over the first 48 hours, burn survivors became more procoagulant while non-survivors became less procoagulant. Differences between survivors and non-survivors appear to be present in the underlying dynamics that contribute to FXa dynamics. Understanding how the individual specific balance of procoagulant and anticoagulant proteins contributes to thrombin and FXa generation could ultimately guide therapy and potentially reduce burn injury-related morbidity and mortality. [ABSTRACT FROM AUTHOR]

Abstract Background A complex inflammatory response mediates the systemic effects of burn shock. Disruption of the endothelial glycocalyx causes shedding of structural glycoproteins, primarily syndecan-1 (SDC-1), leading to endothelial dysfunction. These effects may be mitigated by resuscitative interventions. Materials and methods Sprague–Dawley rats were used to create small, medium, and large burns and uninjured controls. Three different intravenous resuscitation protocols were applied within each group: Lactated Ringer's (LR) alone, LR plus fresh frozen plasma (FFP), or LR plus albumin. Blood was serially collected, and plasma SDC-1 was quantified with enzyme-linked immunosorbent assay. In one cohort, Evan's Blue Dye (EBD) was administered and quantified in lung by spectrophotometry as a functional assay of vascular permeability. In a second cohort, intact SCD-1 was quantified by immunohistochemistry in lung tissue. Statistical analysis employed two-way analysis of variance with multiple comparisons and Student's t -test. Results EBD extraction from lung was significantly greater with higher injury severity versus controls. Extraction decreased significantly in large-burn animals with addition of FFP to LR versus LR-only; addition of albumin to LR did not decrease EBD extraction. Plasma SCD-1 increased in injured animals compared with controls, and changes correlated with injury severity in all resuscitation groups (significance, P < 0.05). Lung SCD-1 staining reflected the results in the EBD assay. Conclusions Addition of FFP, not of albumin, to post-burn resuscitation diminishes vascular leakage associated with large burns. Addition of colloid does not affect SDC-1 shedding as measured in plasma. Ongoing work will further define pathophysiologic mechanisms and potential therapeutic interventions to mitigate injury and promote repair of the endothelial glycocalyx. [ABSTRACT FROM AUTHOR]