Deficient transforming growth factor beta and interleukin-10 responses contribute to the septic death of burned patients

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.

Omega-3 fatty acids impair miR-1-3p-dependent Notch3 down-regulation and alleviate sepsis-induced intestinal injury

Background

Sepsis is a troublesome syndrome that can cause intestinal injury and even high mortality rates. Omega-3 fatty acids (FAs) are known to protect against intestinal damage. Accordingly, the current study set out to explore if omega-3 FAs could affect sepsis-induced intestinal injury with the involvement of the microRNA (miR)-1-3p/Notch3-Smad axis.

Methods

First, cecal ligation and perforation (CLP) was performed to establish septic mouse models in C57BL/6J mice, and mouse intestinal epithelial MODE-K cells were induced by lipopolysaccharide (LPS) to establish sepsis cell models. The CLP-induced septic mice or LPS-exposed cells were subjected to treatment with Omega-3 FAs and activin (Smad signaling activator), miR-1-3p inhibitor and over-expressed/short hairpin RNA (oe-/sh)-Notch3 to explore their roles in inflammation, intestinal oxidative stress and cell apoptosis. A dual-luciferase reporter gene assay was further performed to verify the regulatory relationship between miR-1-3p and Notch3.

Results

Omega-3 FAs inhibited CLP-induced intestinal injury and ameliorated LPS-induced intestinal epithelial cell injury by down-regulating miR-1-3p, as evidenced by decreased levels of tumor necrosis factor-α, interleukin-1β (IL-1β) and IL-6, in addition to diminished levels of reactive oxygen species, malondialdehyde levels and superoxide dismutase activity. Furthermore, miR-1-3p could down-regulate Notch3, which inactivated the Smad pathway.

Conclusion

Collectively, our findings indicated that omega-3 FAs elevate the expression of Notch3 by down-regulating miR-1-3p, and then blocking the Smad pathway to alleviate intestinal epithelial inflammation and oxidative stress injury caused by sepsis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00425-w.

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.

Potential Targets to Mitigate Trauma- or Sepsis-Induced Immune Suppression

In sepsis and trauma, pathogens and injured tissue provoke a systemic inflammatory reaction which can lead to overwhelming inflammation. Concurrent with the innate hyperinflammatory response is adaptive immune suppression that can become chronic. A current key issue today is that patients who undergo intensive medical care after sepsis or trauma have a high mortality rate after being discharged. This high mortality is thought to be associated with persistent immunosuppression. Knowledge about the pathophysiology leading to this state remains fragmented. Immunosuppressive cytokines play an essential role in mediating and upholding immunosuppression in these patients. Specifically, the cytokines Interleukin-10 (IL-10), Transforming Growth Factor-β (TGF-β) and Thymic stromal lymphopoietin (TSLP) are reported to have potent immunosuppressive capacities. Here, we review their ability to suppress inflammation, their dynamics in sepsis and trauma and what drives the pathologic release of these cytokines. They do exert paradoxical effects under certain conditions, which makes it necessary to evaluate their functions in the context of dynamic changes post-sepsis and trauma. Several drugs modulating their functions are currently in clinical trials in the treatment of other pathologies. We provide an overview of the current literature on the effects of IL-10, TGF-β and TSLP in sepsis and trauma and suggest therapeutic approaches for their modulation.

The Effects of Two Different Burn Dressings on Serum Oxidative Stress Indicators in Children with Partial Burn

In this study, we evaluated and compared the effect of treatment with a hydrofiber dressing with silver (HFAg) and a polylactic membrane (PLM) on systemic oxidative stress in systemic inflammatory reaction in thermal burn injuries in children. A prospective randomized and matched pairing study of 20 to 50% of TBSA was performed from children equal to both sexes affected by thermal injuries. The control group was included in normal children of both sexes. Serum malondialdehyde (MDA), total antioxidant capacity (TAC), total oxidant capacity (TOC), and glutathione (GSH) levels were analyzed and the results were analyzed statistically. In this study, it was found that PLM treatment increased TAC and GSH levels in burn patients significantly more than the other group. With the use of PLM, TOC decreased to normal level from day 3. In the HFAg group, TAC and GSH levels began to increase on the seventh day. On the first day of the burn, the TOC level started to increase. This increase continued on days 7 and 14. The TOC level began to fall on the 21st day. The increase in TAC was higher in the PLM group. In the PLM group, TOC fell faster. As a result, we think that different burn dressings can have different systemic effects. We can speculate that PLM has an antioxidant effect in the burn tissue due to high lactate content. Therefore, PLM may have decreased serum oxidative stress indicators more effectively than HFAg.

Function and mechanism of pyrin and IL-10 in the regulation of the inflammasome in pulmonary vascular endothelial cells following hemorrhagic shock

The present study aimed to evaluate the function of pyrin and interleukin-10 (IL-10) and the potential mechanisms underlying the regulation of inflammation in pulmonary vascular endothelial cells (ECs) following hemorrhagic shock (HS). Adult female Sprague-Dawley rats were divided into 4 groups (n=6 in each group) to examine the changes in pyrin expression following HS-lipopolysaccharide (LPS) administration, including the following groups: A sham operation (SM) + tracheal injection of saline (SAL) group; a HS + SAL group; a SM + LPS group (with a tracheal injection of endotoxin); and a HS + LPS group. An additional 4 groups were used to evaluate the function of IL-10, by the additional intratracheal injection of recombinant IL-10. Western blot analysis and immunofluorescence were performed in order to investigate the changes to pyrin and IL-10 expression in pulmonary vascular ECs. The expression levels of pyrin in the SM + LPS group were significantly increased in comparison with the SM + SAL group (P<0.01). Additionally, the expression levels of pyrin were significantly increased in the HS + LPS group compared with the HS + SAL group (P<0.01). The expression levels of caspase-1 were significantly increased in the HS + LPS group compared with those in the other three groups (P<0.01). The expression levels of pyrin in the HS + LPS + IL-10 group were significantly increased compared with the HS + LPS group (P<0.01). The expression levels of caspase-1 were significantly decreased following IL-10 treatment compared with those in the HS + LPS group (P<0.01). Therefore, HS attenuated LPS-induced pyrin expression in pulmonary vascular ECs and may also inhibit the expression of IL-10, resulting in the activation of caspase-1 subsequent to a second LPS insult.

Vitamin D in burn-injured patients

Recently, many studies have demonstrated pleotropic effects of vitamin D, including immune modulation and cardiovascular system activity. Sufficient vitamin D concentrations and supplementation of vitamin D may be of benefit in burn-injured patients. Low 25(OH)D has been observed in nearly all pediatric and most adult burn patients. Vitamin D has primarily been studied in pediatric burn patients, focusing on bone marker measurements and the incidence of fractures. The preferred vitamin D dose, formulation, and route of administration remain unknown, and there is limited data on the impact of vitamin D status on clinical outcomes. Further research should focus on determining optimal monitoring strategies, supplementation regimens and clinical outcomes like mortality, length of stay and incidence of sepsis.

Survival analysis and mortality predictors of hospitalized severe burn victims in a Malaysian burns intensive care unit

Background

Prognostic measures to determine burn mortality are essential in evaluating the severity of individual burn victims. This is an important process of triaging patients with high risk of mortality that may be nursed in the acute care setting. Malaysian burn research is lacking with only one publication identified which describes the epidemiology of burn victims. Therefore, the objective of this study was to go one step further and identify the predictors of burn mortality from a Malaysian burns intensive care unit (BICU) which may be used to triage patients at higher risk of death.

Methods

This is a retrospective cohort study of all admissions to Hospital Sultan Ismail’s BICU from January 2010 till October 2015. Admission criteria were in accordance with the American Burn Association guidelines, and risk factors of interest were recorded. Data was analyzed using simple logistic regression to determine significant predictors of mortality. Survival analysis with time to death event was performed using the Kaplan-Meier survival curve with log-rank test.

Results

Through the 6-year period, 393 patients were admitted with a male preponderance of 73.8%. The mean age and length of stay were 35.6 (±15.72) years and 15.3 (±18.91) days. There were 48 mortalities with an overall mortality rate of 12.2%. Significant risk factors identified on simple logistic regression were total body surface area (TBSA) > 20% (p < 0.001), inhalation injury (p < 0.001) and presence of early systemic inflammatory response syndrome (SIRS) (p < 0.001). Survival analysis using Kaplan-Meier survival curve showed similar results with TBSA > 20%, presence of SIRS, mechanical ventilation and inhalation injury which were associated with poorer survival (p < 0.001).

Conclusion

The predictors of mortality identified in a Malaysian BICU were TBSA > 20%, early SIRS, mechanical ventilation and inhalation injury which were associated with poorer survival outcome. The immunological response differs from individual patients and influenced by the severity of burn injury. Early SIRS on admission is an important predictor of death and may represent the severity of burn injury. Patients who required mechanical ventilation were associated with mortality and it is likely related to the severity of pulmonary insults sustained by individual patients. This data is important for outcome prognostication and mortality risk counselling in severely burned patients.

Increased serum concentrations of soluble ST2 predict mortality after burn injury

Background:

Large burn injuries induce a systemic response in affected patients. Soluble ST2 (sST2) acts as a decoy receptor for interleukin-33 (IL-33) and has immunosuppressive effects. sST2 has been described previously as a prognostic serum marker. Our aim was to evaluate serum concentrations of sST2 and IL-33 after thermal injury and elucidate whether sST2 is associated with mortality in these patients.

Methods:

We included 32 burn patients (total body surface area [TBSA] >10%) admitted to our burn intensive care unit and compared them to eight healthy probands. Serum concentrations of sST2 and IL-33 were measured serially using an enzyme-linked immunosorbent assay (ELISA) technique.

Results:

The mean TBSA was 32.5%±19.6%. Six patients (18.8%) died during the hospital stay. Serum analyses showed significantly increased concentrations of sST2 and reduced concentrations of IL-33 in burn patients compared to healthy controls. In our study cohort, higher serum concentrations of sST2 were a strong independent predictor of mortality.

Conclusions:

Burn injuries cause an increment of sST2 serum concentrations with a concomitant reduction of IL-33. Higher concentrations of sST2 are associated with increased in-hospital mortality in burn patients.

Xuebijing Protects Rats from Sepsis Challenged with Acinetobacter baumannii by Promoting Annexin A1 Expression and Inhibiting Proinflammatory Cytokines Secretion

Xuebijing (XBJ) injection is a herbal medicine that has been widely used in the treatment of sepsis in China; however, its role in the development and progression of Acinetobacter baumannii sepsis and the underlying mechanisms remain uninvestigated. In the present study, fifty-four male Wistar rats were randomly assigned to normal-control group, sepsis-control group, and sepsis + XBJ group, each containing three subgroups of different treatment time periods (6, 12, and 24 hrs following injection, resp.). The sepsis model was established by intraperitoneal injection of A. baumannii ATCC 19606. For XBJ treatment, 4 mL/kg XBJ was administrated simultaneously by intravenous injection through caudal vein every 12 hrs. All animals demonstrated ill state, obvious intestinal dysfunction, histopathological lung damages, and overactive inflammatory responses after A. baumannii infection, and these events could be partially reversed by XBJ treatment from the beginning of infection. XBJ induced an increase in the expression of anti-inflammatory mediator annexin A1; however, two proinflammatory cytokines, interleukin-8 (IL-8) and tumor necrosis factor- α (TNF- α ), were decreased at the each monitored time point. These findings suggested that XBJ via its cytokine-mediated anti-inflammatory effects might have a potential role in preventing the progression of A. baumannii infection to sepsis by early administration.

Bai-hu-tang, ancient chinese medicine formula, may provide a new complementary treatment option for sepsis

Bai-Hu-Tang (BHT) has been broadly applied to treating the early stage of acute infection with systemic inflammation for two thousand years in Chinese medicine. We explore whether BHT is beneficial in treating sepsis and its effects on proinflammatory cytokine, interleukin-6, and anti-inflammatory cytokine interleukin-10, in which both play key roles in the progress of sepsis. Thirty-six male Sprague-Dawley rats were randomized into six groups, with cecal ligation and puncture (CLP) performed in all but the sham-control group. Rats in CLP + BHT-L6 and CLP + BHT-H6 groups, respectively, received a low (0.45 g/kg) and high doses (0.9 g/kg) of BHT, 6 hrs postoperatively. CLP + BHT-L12 and CLP + BHT-H12 groups, respectively, received low and high doses of BHT, 12 hrs postoperatively. Sham-control and sepsis-control groups received distilled water (1 mL) as vehicle, 6 hrs postoperatively. Serial blood samples were drawn before operation, as baseline, and at 4, 8, and 12 hrs postoperatively for IL-6 and IL-10 assay. All rats were monitored for 3 days for survival study. Rats in the CLP + BHT-H6 group had significantly higher survival rate (80%) and significantly lower levels of both IL-6 and IL-10 at 12 hrs postoperatively than those in the sepsis-control group. Results suggested that BHT may be a new complementary treatment option for sepsis.

Hemorrhagic shock augments Nlrp3 inflammasome activation in the lung through impaired pyrin induction

Hemorrhagic shock (HS) promotes the development of systemic inflammatory response syndrome and organ injury by activating and priming the innate immune system for an exaggerated inflammatory response through, as of yet, unclear mechanisms. IL-1β also plays an important role in the development of post-HS systemic inflammatory response syndrome and active IL-1β production is tightly controlled by the inflammasome. Pyrin, a protein of 781 aa with pyrin domain at the N-terminal, negatively regulates inflammasome activation through interaction with nucleotide-binding oligomerization domain-like receptor protein (NLRP). Expression of pyrin can be induced by LPS and cytokines, and IL-10 is a known potent inducer of pyrin expression in macrophages. In the current study, we tested the hypothesis that HS downregulates IL-10 and therefore decreases pyrin expression to promote inflammasome activation and subsequent IL-1β processing and secretion in the lungs. Our results show that LPS, while activating Nlrp3 inflammasome in the lungs, also induced pyrin expression, which in turn suppressed inflammasome activation. More importantly, LPS-mediated upregulation of IL-10 enhanced pyrin expression, which serves, particularly in later phases, as a potent negative-feedback mechanism regulating inflammasome activation. However, HS-mediated suppression of IL-10 expression in alveolar macrophages attenuated the upregulation of pyrin in alveolar macrophages and lung endothelial cells and thereby significantly enhanced inflammasome activation and IL-1β secretion in the lungs. This study demonstrates a novel mechanism by which HS suppresses negative-feedback regulation of Nlrp3 inflammasome to enhance IL-1β secretion in response to subsequent LPS challenge and so primes for inflammation.

Prognostic scoring systems in burns: a review

Survival after burn has steadily improved over the last few decades. Patient mortality is, however, still the primary outcome measure for burn care. Scoring systems aim to use the most predictive premorbid and injury factors to yield an expected likelihood of death for a given patient. Age, burn surface area and inhalational injury remain the mainstays of burn prognostication, but their relative weighting varies between scoring systems. Biochemical markers may hold the key to predicting outcomes in burns. Alternatively, the incorporation of global scales such as those used in the general intensive care unit may have relevance in burn patients. Outcomes other than mortality are increasingly relevant, especially as mortality after burns continues to improve. The evolution of prognostic scoring in burns is reviewed with specific reference to the more widely regarded measures. Alternative approaches to burn prognostication are reviewed along with evidence for the use of outcomes other than mortality. The purpose and utility of prognostic scoring in general is discussed with relevance to its potential uses in audit, research and at the bedside.

Burn trauma induces early HMGB1 release in patients: its correlation with cytokines

High-mobility group box protein 1 (HMGB1) is a nuclear protein that may be released actively from monocytes and macrophages or passively from necrotic or damaged cells. Several experimental data suggest that burn injury is accompanied by elevated plasma HMGB, but there are only few data available about its changes in burned patients. The aim of this study was to follow the time course and the prognostic value of plasma HMGB1 and cytokine changes in patients with severe burn injury affecting more than 10% of body surface area (n = 26). Blood samples were taken on admission and on the following 5 days. Plasma HMGB1 concentration was measured by the enzyme-linked immunosorbent assay method, whereas IL-6, IL-8, and IL-10 were assayed by the cytometric bead array kit. The HMGB1 and IL-10 concentrations were elevated on admission and gradually decreased thereafter. Significant differences were observed between survivors and nonsurvivors in HMGB1 (P < 0.01) and IL-10 (P < 0.001) concentrations on admission with higher levels in nonsurvivors. IL-6 and IL-8 started to increase markedly from day 2. Positive correlation (r = 0.669, P < 0.01) was found between burned body surface and HMGB1 on admission. Receiver operating characteristic analysis of data on admission showed that at a level of 16 ng/mL, HMGB1 indicated lethality, with 75.0% sensitivity and 85.7% specificity. Using the cutoff level of 14 pg/mL, IL-10 predicted intensive care unit mortality, with 85.7% sensitivity and 84.2% specificity. Very early HMGB1 and IL-10 release may have an important impact on the immune function of patients after burn trauma.

Role of the mTOR pathway in LPS-activated monocytes: influence of hypertonic saline

BACKGROUND

As heightened protein synthesis is the hallmark of many inflammatory syndromes, we hypothesize that the mammalian target of rapamycin (mTOR) pathway, which control the cap-dependent translation initiation phase, was activated by lipopolysaccharide (LPS). In addition, we studied the effect of hypertonic saline solution (HTS) on the mTOR cascade in peripheral blood mononuclear cells (PBMCs).

MATERIALS AND METHODS

PBMCs were isolated from healthy volunteers and treated with LPS. Cells were pretreated with phosphatidylinositol 3-kinase (PI3K) and mTOR inhibitors, or with HTS. Supernatants were harvested 20 h following LPS treatment, and interleukin-10 (IL-10), interleukin-6 (IL-6) and tumor necrosis alpha (TNFα) were analyzed by ELISA. Immunoblot experiments were performed for components of the PI3K/Akt/mTOR pathway at various time points. RNA was extracted after 90 min for real-time RT-PCR quantification.

RESULTS

The mTOR pathway is activated in PBMCs within 1 h of LPS stimulation. Pretreatment with rapamycin, a specific inhibitor of mTOR, resulted in a significant decrease of IL-10 and IL-6 translation and expression but did not affect the LPS-induced TNFα production. Both the mTOR pathway and the LPS-induced IL-6 production were down-regulated by HTS pretreatment.

CONCLUSIONS

The PI3k/Akt/mTOR cascade modulates LPS-induced cytokines production differentially. IL-10 and IL-6 expression are both up-regulated by activation of the mTOR pathway in response to LPS in PBMCs, while TNFα is not controlled by the mTOR cascade. Meanwhile, pretreatment of PBMCs with a HTS solution suppresses mTOR activity as well as LPS-induced IL-6, suggesting a more central role for mTOR as a regulator of the immuno-inflammatory response.

Lamellar pro-inflammatory cytokine expression patterns in laminitis at the developmental stage and at the onset of lameness: innate vs. adaptive immune response

REASONS FOR PERFORMING STUDY

Recent research has indicated that inflammation plays a role in the early stages of laminitis and that, similar to organ failure in human sepsis, early inflammatory mechanisms may lead to downstream events resulting in lamellar failure. Characterisation of the type of immune response (i.e. innate vs. adaptive) is essential in order to develop therapeutic strategies to counteract these deleterious events.

OBJECTIVES

To quantitate gene expression of pro-inflammatory cytokines known to be important in the innate and adaptive immune response during the early stages of laminitis, using both the black walnut extract (BWE) and oligofructose (OF) models of laminitis.

METHODS

Real-time qPCR was used to assess lamellar mRNA expression of interleukins-1beta, 2, 4, 6, 8, 10, 12 and 18, and tumour necrosis factor alpha and interferon gamma at the developmental stage and at the onset of lameness.

RESULTS

Significantly increased lamellar mRNA expression of cytokines important in the innate immune response were present at the developmental stage of the BWE model, and at the onset of acute lameness in both the BWE model and OF model. Of the cytokines characteristic of the Th1 and Th2 arms of the adaptive immune response, a mixed response was noted at the onset of acute lameness in the BWE model, whereas the response was skewed towards a Th1 response at the onset of lameness in the OF model.

CONCLUSIONS

Lamellar inflammation is characterised by strong innate immune response in the developmental stages of laminitis; and a mixture of innate and adaptive immune responses at the onset of lameness.

POTENTIAL RELEVANCE

These results indicate that anti-inflammatory treatment of early stage laminitis (and the horse at risk of laminitis) should include not only therapeutic drugs that address prostanoid activity, but should also address the marked increases in lamellar cytokine expression.

Transforming growth factor-beta and angiotensin in fibrosis and burn injuries

This review considers the roles of transforming growth factor-beta (TGF-beta), the signaling Smad proteins, and angiotensin II (AT II) in conditions leading to human fibrosis. The goal is to update the burn practitioner and researcher about this important pathway and to introduce AT II as a possible synergistic signal to TGF-beta in burn scarring. Literature searches of the MEDLINE database were performed for English manuscripts combinations of TGF-beta, Smad, angiotensin, fibrosis, burn, and scar. AT II and TGF-beta both activate the Smad protein system, which leads to the expression of genes related to fibrosis. In fibrotic conditions, such as tubulointerstitial nephritis, systemic sclerosis, and myocardial infarctions, AT II acts both independently and synergistically with TGF-beta. Both AT II and TGF-beta act through a messenger system, the Smad proteins that lead to excessive extracellular matrix formation. Treatment and research implications are reviewed. The interaction between AT II and TGF-beta leading to fibrosis is well described in some human diseases. This pathway may be of importance in human burn scarring as well.

Characterization of the inflammatory response during acute and post-acute phases after severe burn

Severe burn causes a pronounced hypermetabolic response characterized by catabolism and extensive protein wasting. We recently found that this hypermetabolic state is driven by a severe inflammatory response. We characterized in detail the kinetics of serum levels of a panel of cytokines in a rat model, which may serve as reference for the development of therapeutic interventions applicable to humans. Male Sprague-Dawley rats (n = 8) received a full-thickness burn of 60% total body surface area. Serum was harvested 1, 3, 6, 12, 24, 48, 96, and 168 h after burn. Eight serum cytokines commonly used to assess the inflammatory response in humans, such as IL-1beta, IL-6, IL-10, TNF, vascular endothelial growth factor, and monocyte chemotactic protein 1, and the rat-specific cytokines cytokine-induced neutrophil chemoattractant (CINC) 1, CINC-2, and CINC-3 were measured by enzyme-linked immunosorbent assay technique and were compared with controls (n = 4). Statistical analysis was conducted using the t test, with P < 0.05 considered as significantly different. Thermal injury resulted in significantly increased serum levels of IL-1beta, IL-6, IL-10, monocyte chemotactic protein 1, CINC-1, CINC-2, and CINC-3 when compared with the concentrations detected in nonburned rats (P < 0.05). Serum levels of TNF-alpha and vascular endothelial growth factor in burned rats were not found to be significantly different to controls. Burn causes a profound inflammatory response in rats. Specific cytokines known to increase in humans postburn such as IL-1 beta, IL-6, IL-10, MCP-1, and IL-8 (CINC-1, CINC-2, and CINC-3 in the rat) were also observed in our rat burn model, which now allows us to study new anti-inflammatory treatment options.

Cytokine expression profile over time in burned mice

The persistent inflammatory response induced by a severe burn increases patient susceptibility to infections and sepsis, potentially leading to multi-organ failure and death. In order to use murine models to develop interventions that modulate the post-burn inflammatory response, the response in mice and the similarities to the human response must first be determined. Here, we present the temporal serum cytokine expression profiles in burned mice in comparison to sham mice and human burn patients. Male C57BL/6 mice were randomized to control (n=47) or subjected to a 35% TBSA scald burn (n=89). Mice were sacrificed 3, 6, 9, 12, 24, and 48 h and 7, 10, and 14 days post-burn; cytokines were measured by multi-plex array. Following the burn injury, IL-6, IL-1beta, KC, G-CSF, TNF, IL-17, MIP-1alpha, RANTES, and GM-CSF were increased, p<0.05. IL-2, IL-3, and IL-5 were decreased, p<0.05. IL-10, IFN-gamma, and IL-12p70 were expressed in a biphasic manner, p<0.05. This temporal cytokine expression pattern elucidates the pathogenesis of the inflammatory response in burned mice. Expression of 11 cytokines were similar in mice and children, returning to lowest levels by post-burn day 14, confirming the utility of the burned mouse model for development of therapeutic interventions to attenuate the post-burn inflammatory response.

Temporal cytokine profiles in severely burned patients: a comparison of adults and children

A severe burn leads to hypermetabolism and catabolism resulting in compromised function and structural changes of essential organs. The release of cytokines has been implicated in this hypermetabolic response. The severity of the hypermetabolic response following burn injury increases with age, as does the mortality rate. Due to the relationship between the hypermetabolic and inflammatory responses, we sought to compare the plasma cytokine profiles following a severe burn in adults and in children. We enrolled 25 adults and 24 children who survived a flame burn covering more than 20% of total body surface area (TBSA). The concentrations of 22 cytokines were measured using the Linco multiplex array system (St. Charles, MO, USA). Large perturbations in the expression of pro- and anti-inflammatory cytokines were seen following thermal injury. During the first week following burn injury, IFN-gamma, IL-10, IL-17, IL-4, IL-6, and IL-8 were detected at significantly higher levels in adults compared with children, P < 0.05. Significant differences were measured during the second week post-burn for IL-1beta (higher in children) and IL-5 (higher in adults), P < 0.05. IL-18 was more abundant in children compared with adults during the third week post-burn, P < 0.05. Between post-burn d 21 and d 66, IL-1alpha was detected at higher concentrations in pediatric compared with adult patients, P < 0.05. Only GM-CSF expression was significantly different at all time points; it was detected at lower levels in pediatric patients, P < 0.05. Eotaxin, G-CSF, IL-13, IL-15, IP-10, MCP-1, and MIP-1alpha were detected at significantly different concentrations in adult compared with pediatric patients at multiple time points, P < 0.05. There were no differences in IL-12, IL-2, IL-7, or TNF levels in adult compared with pediatric burn patients at any of these time points. Following severe flame burns, the cytokine profiles in pediatric patients differ compared with those in adult patients, which may provide insight with respect to the higher morbidity rate in adults. Furthermore, the dramatic discrepancies observed in plasma cytokine detection between children and adults suggest that these two patient populations may benefit from different therapeutic interventions to achieve attenuation of the post-burn inflammatory response.

Potential cellular and molecular causes of hypertrophic scar formation

A scar is an expected result of wound healing. However, in some individuals, and particularly in burn victims, the wound healing processes may lead to a fibrotic hypertrophic scar, which is raised, red, inflexible and responsible for serious functional and cosmetic problems. It seems that a wide array of subsequent processes are involved in hypertrophic scar formation, like an affected haemostasis, exaggerated inflammation, prolonged reepithelialization, overabundant extracellular matrix production, augmented neovascularization, atypical extracellular matrix remodeling and reduced apoptosis. Platelets, macrophages, T-lymphocytes, mast cells, Langerhans cells and keratinocytes are directly and indirectly involved in the activation of fibroblasts, which in turn produce excess extracellular matrix. Following the chronology of normal wound healing, we unravel, clarify and reorganize the complex molecular and cellular key processes that may be responsible for hypertrophic scars. It remains unclear whether these processes are a cause or a consequence of unusual scar tissue formation, but raising evidence exists that immunological responses early following wounding play an important role. Therefore, when developing preventive treatment modalities, one should aim to put the early affected wound healing processes back on track as quickly as possible.

Clinical evaluation of proinflammatory cytokine inhibitors (sTNFR I, sTNFR II, IL-1 ra), anti-inflammatory cytokines (IL-10, IL-13) and activation of neutrophils after burn-induced inflammation

The study was aimed at evaluating the involvement of sTNFR I, sTNFR II, IL-1 ra, IL-10, IL-13 and reactive oxygen species (ROS) in systemic inflammatory response syndrome (SIRS) development in severely burned children and at assessing the prognostic value of the immunological markers studied. The study comprised 37 patients (17 burned children and 20 controls). Serum levels of the markers determined by means of ELISA and respiratory burst of neutrophils as well as p55 and p75 tumour necrosis factor-alpha (TNF-alpha) receptor expression using flow cytometry were evaluated twice. The burned children presented significantly higher levels of IL-10 and cytokine inhibitors within the first 6-24 h after injury compared with controls (P < 0.05). The decreased oxygen metabolism of neutrophils and increased TNF-alpha receptor expression were found on admission. Moreover, a significant decrease in initially high sTNFR I, sTNFR II, IL-1 ra, IL-10, IL-13 concentrations (P < 0.05) and reduced expression of TNF-alpha receptors (P < 0.05) were observed after burn therapy, whereas ROS generation evidently augmented (P < 0.05). Four of our children who developed hypovolaemic shock revealed a significantly lower ROS generation and higher concentrations of soluble TNF-alpha receptors and IL-1 ra together with IL-10, IL-13 compared with children with good outcome (P < 0.05). Our results revealed the involvement of both ROS, soluble TNF-alpha receptors and IL-1 ra in the development of SIRS in burned children; their monitoring allows for an assessment of the systemic inflammatory reaction activity. The neutrophil BURSTTEST and IL-1 ra might have been clinically helpful markers of SIRS prognosis.

Protective effect of Fab' in immunoglobulin Y against lipopolysaccharide on intestinal mucosa during the early stage in severely burned gut-derived endotoxemia mice

AIM: To investigate the protective effect of Fab' against endotoxin on intestinal mucosa during the early stage in severely burned gut-derived endotoxemia mice, and to explore a new method for preventing and curing burn sepsis.

METHODS: The severely burned gut-derived endotoxemia mice model was used, and the mice were divided into 3 groups: control group (group A), burn group (group B) and Fab' treatment group (group C). At the 6^th, 12^th, 24^th and 48th h after burn injury, the levels of serum tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-10 (IL-10) were determined by enzyme-linked immunosorbent assay. Intestinal tissues were collected for pathological examination.

RESULTS: In comparison with those in group A, the levels of serum TNF-α, IL-1β and IL-10 in group B increased significantly and reached the peak 24 h after burn injury (TNF-α: 242.06 ± 3.93 ng/L vs 14.98 ± 1.13 ng/L; IL-1β: 37.86 ± 5.88 ng/L vs 14.39 ± 2.43 ng/L; IL-10: 324.78 ± 65.82 ng/L vs 97.63 ± 20.48 ng/L; all P < 0.01). The levels of TNF-α, IL-1β and IL-10 at 6, 12, 24 and 48 h in group C (6 h: 99.69 ± 10.67, 19.19 ± 1.17, 160.44 ± 24.99 ng/L; 12 h: 172.07 ± 22.47, 22.29 ± 3.32, 185.44 ± 22.30 ng/L; 24 h: 125.98 ± 6.93, 28.39 ± 2.59, 237.11 ± 30.28 ng/L; 48 h: 107.88 ± 5.24, 26.23 ± 2.51, 207.86 ± 20.35 ng/L) were significantly different from those in group B (all P < 0.05). Pathological examination showed a lower degree of intestinal mucosal injury in group C than in compared with group B.

CONCLUSION: The Fab' against endotoxin can significantly decrease the level of serum TNF-α, IL-1β and IL-10 during the early stage in severely burned gut-derived endotoxemia mice, and consequently alleviate the endotoxin-induced injury.

Snapshot assessment of RNA-expression in severely burned patients using the PAXgene™ Blood RNA System: A pilot study

Severe burn induces destabilization of the immune system and the likelihood of multiple organ dysfunction syndrome. Current studies focus on RNA-expression analyses of immune system cells, however, the present methods of analysis are complex, potentially altered by artefacts and therefore not feasible for routine analyses. The new PAXgene Blood RNA System provides "snapshot" analysis of RNA by immediate cell lysis and prevention of RNA-degradation. Using this system the aim of this study was to analyse intracellular cytokine RNA-expression under clinical conditions. Whole blood samples (PAXgene tubes) of nine severely burned patients were drawn at admission and 6, 12, 24, 48 and 72h after trauma during routine treatment. Four healthy individuals served as control. Analysis of RNA-expression of TNF-alpha as pro-inflammatory and IL-10 as anti-inflammatory mediator was performed by RT-PCR. The RNA-expression of TNF-alpha was increased at 72h after burn. The increase occurred mainly in surviving patients. In contrast, RNA-expression of IL-10 was elevated already at 24h and the difference between surviving and deceased patients occurred earlier. We demonstrate for the first time a "snapshot" analysis of cytokine RNA-expression in severely burned patients under routine conditions. The results correspond well to current hypothesis of posttraumatic MODS development.

The "T" in trauma: the helper T-cell response and the role of immunomodulation in trauma and burn patients

BACKGROUND

The immune system undergoes numerous changes after traumatic and burn injuries, including a down-regulation of the TH1 response and up-regulation of the TH2 response.

METHODS

The PubMed, Medline, and Ovid search engines were queried for relevant human studies. Bibliographies were also meticulously reviewed.

RESULTS

An interesting and potentially clinically relevant pattern of immune dysregulation exists after injury. The type 1 T-helper cell (TH1) response is suppressed as illustrated by diminished interleukin (IL)-2, interferon (IFN)-gamma, and IL-12 levels after major injury. The enhancement of the TH2 response is marked by elevated IL-10 and IL-4. Certain cytokine profiles, ratios, and polymorphisms may help identify patients at increased risk of systemic inflammatory response syndrome (SIRS), sepsis, multiple organ failure (MOF), and deep venous thrombosis. The most promising prognostic indicators to date are decreased production of the IL-12, elevated IL-10, soluble IL-2 receptor-a (sIL-2Ra), and IL-18 levels, IL-18 promoter polymorphisms, the IL-6:IL-10 ratio, and the degree of TH1 suppression as measured by diminished IL-2 and IFN-gamma. The Cytokine sections are subdivided into basic science, human studies, animal studies (when necessary), and directed therapeutics. The outcomes of sepsis, SIRS, or MOF are generally discussed together.

CONCLUSIONS

T-cell-specific immunologic changes occur after major injury. Identification of those TH1/TH2 cytokine profiles associated with worse prognosis may one day allow clinicians to risk stratify injured patients and identify those at increased risk of developing SIRS, sepsis, MOF, and deep venous thrombosis. Immune-targeted therapies may eventually serve as effective treatments in the acute setting to decrease morbidity and mortality, and to improve the management and prognosis of those patients at risk for developing postinjury complications.

Inhalation injury in severely burned children does not augment the systemic inflammatory response

Introduction

Inhalation injury in combination with a severe thermal injury increases mortality. Alterations in inflammatory mediators, such as cytokines, contribute to the incidence of multi-organ failure and mortality. The aim of the present study was to determine the effect of inhalation injury on cytokine expression in severely burned children.

Methods

Thirty severely burned pediatric patients with inhalation injury and 42 severely burned children without inhalation injury were enrolled in the study. Inhalation injury was diagnosed by bronchoscopy during the first operation. Blood was collected within 24 hours of admission and again at five to seven days following admission. Cytokine expression was profiled using multi-plex antibody-coated beads. Significance was accepted at a p value of less than 0.05.

Results

The mean percentages of total body surface area burned were 67% ± 4% (56% ± 6%, third-degree burns) in the inhalation injury group and 60% ± 3% (45% ± 3%, third-degree burns) in the non-inhalation injury group (p value not significant [NS]). Mean age was 9 ± 1 years in the inhalation injury group and 8 ± 1 years in the non-inhalation injury group (p value NS). Time from burn to admission in the inhalation injury group was 2 ± 1 days compared to 3 ± 1 days in the non-inhalation injury group (p value NS). Mortalities were 40% in the inhalation injury group and 12% in the non-inhalation injury group (p < 0.05). At the time of admission, serum interleukin (IL)-7 was significantly increased in the non-inhalation injury group, whereas IL-12p70 was significantly increased in the inhalation injury group compared to the non-inhalation injury group (p < 0.05). There were no other significant differences between groups. Five to seven days following admission, all cytokines decreased with no differences between the inhalation injury and non-inhalation injury cohorts.

Conclusion

In the present study, we show that an inhalation injury causes alterations in IL-7 and IL-12p70. There were no increased levels of pro-inflammatory cytokines, indicating that an inhalation injury in addition to a burn injury does not augment the systemic inflammatory response early after burn.

Longitudinal course and clinical significance of TGF-beta1, sL- and sE-Selectins and sICAM-1 levels during severe acute stress in children

OBJECTIVES

To elucidate the potential role of circulating levels of transforming growth factor-beta1 (TGF-beta1), soluble intercellular adhesion molecule-1 (sICAM-1), soluble L- and sE-Selectins (sL- and sE-Selectins) in children with sepsis, traumatic brain injury (TBI) or acute respiratory distress syndrome (ARDS).

DESIGN AND METHODS

Levels of TGF-beta1, sICAM-1, L- and sE-Selectins were determined using solid-phase sandwich enzyme-linked immunosorbent assay in plasma of 10 patients with sepsis, 10 patients with TBI, 10 patients with ARDS, compared to 10 ventilated controls with chronic illness but not in acute stress, on days 1, 3, 5, 7 and 10.

RESULTS

The highest values of sICAM-1 were observed in patients with TBI (p<0.001) and those of sE-Selectin in patients with sepsis (p=0.0001). Patients in the control group did not show an elevation of sE-Selectin and sICAM-1 levels longitudinally. Increased levels of measured molecules (TGF-beta1, p<0.02, sE-Selectin, p<0.02, sL-Selectin, p=0.06, sICAM-1, p<0.03) were demonstrated among survivors in the sepsis and ARDS groups of patients and were positively correlated with length of stay (p<0.04) and mechanical ventilation (p<0.001).

CONCLUSIONS

A sustained increase of adhesion molecules occurs during acute stress in children which may contribute to morbidity in patients with sepsis (sE-Selectin) or traumatic brain injury (sICAM-1). Suppression of the expected response of sE-Selectins, s-ICAM-1 and TGF-beta1 is associated with poor outcome.

SERUM CYTOKINE DIFFERENCES IN SEVERELY BURNED CHILDREN WITH AND WITHOUT SEPSIS

The aim was to determine whether serum cytokine profiling early after burn can be used to identify patients at high risk of developing and subsequently dying of sepsis. A case series study was designed to determine whether serum cytokine profiling allows identification of patients at highest risk of developing and dying of sepsis at the time of hospital admission. All patients were treated according to the standard of burn care at our facility. Forty-four children (1-19 years old) with more than 40% of total body surface area and admitted within 7 days postburn were studied. None had infections or sepsis at the time of admission. Serum was collected before the first operation, and concentrations of 17 cytokines were measured. Diagnosis of sepsis was made at autopsy with identification of the pathogen. Fifteen patients developed sepsis and died, whereas 29 patients did not develop sepsis and survived. Significant elevations in serum interleukin (IL) 6, IL-8, IL-10, granulocyte-monocyte colony-stimulating factor, interferon gamma (IFN-gamma), tumor necrosis factor (TNF), and IL-12 p70 were found at the time of admission of patients who subsequently developed and died of sepsis when compared with burned patients who did not develop sepsis (P < 0.05). Multiple logistic regression analysis revealed that patients with a combination of elevated IL-6 and IL-12 p70 and lower TNF had an elevated risk of dying of sepsis. Serum IL-6, IL-8, IL-10, granulocyte-monocyte colony-stimulating factor, IFN-gamma, TNF, and IL-12 p70 are expressed differently in patients who die of sepsis versus those who never become septic. In addition, serum IL-6, IL-12 p70, and TNF can be used to identify burned patients who are at high risk of death from sepsis.

Cytokine expression profile over time in severely burned pediatric patients

A severe burn leads to hypermetabolism and catabolism resulting in compromised function and structure of essential organs. The massive release of cytokines is implicated in this hypermetabolic response. The aim of the present study was to compare cytokine expression profiles from severely burned children without signs of infections or inhalation injury (n = 19) to the cytokine profiles from normal, noninfected, nonburned children (n = 14). The Bio-Plex suspension array system was used to measure the concentration of 17 cytokines. The expression of proinflammatory and anti-inflammatory cytokines was maximal during the first week after thermal injury. Significant increases were measured for 15 mediators during the first week after thermal injury: interleukin (IL) 1beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 p70, IL-13, IL-17, interferon gamma, monocyte chemoattractant protein 1, macrophage inflammatory protein 1beta, and granulocyte colony-stimulating factor (P < 0.05). Granulocyte-macrophage colony-stimulating factor was significantly increased during the second week after burn (P < 0.05). Within 5 weeks, the serum concentrations of most cytokines decreased, approaching normal levels. When compared with the cytokine levels measured in normal children, a total of 16 cytokines were significantly altered (P < 0.05). After severe burn, a specific cytokine expression profile is observed in patients without complications such as inhalation injury or sepsis. The cytokine concentrations decrease during 5 weeks after burn but remain elevated over nonburned values. Furthermore, the elevation in most serum cytokine levels during the first week after burn may indicate a potential window of opportunity for therapeutic intervention.

Platelet depletion in mice increases mortality after thermal injury

Platelets play a fundamental role in maintaining hemostasis and have been shown to participate in innate and adaptive immunity. However, the role of platelets in the immune response to injury remains undefined. We tested the importance of platelets in the host response to serious injury in a newly developed platelet-deficient mouse model. Wild-type and platelet-depleted C57BL/6J mice underwent a 25% full-thickness total body surface area thermal or sham injury. Platelet-deficient mice showed survival of 51% at 48 hours after injury compared with 94% to 100% survival in experimental control mice (P < .001). Necropsy and histology ruled out hemorrhage and hypovolemia as causes of death. Percentages of peripheral blood monocytes (P < .01) and neutrophils (P < .05) were increased between 36 and 48 hours after thermal injury in platelet-deficient mice compared with control mice. Plasma levels of TNFalpha (P < .001), IL-6 (P < .001), and MCP-1 (P < .05) were also elevated by 24 hours whereas levels of TGFbeta(1) were reduced between 24 and 36 hours following injury in platelet-depleted mice (P < .001) compared with control mice. Our findings demonstrate for the first time that platelets play a critical protective role during the host response to injury. Moreover, our findings suggest that platelets and, more importantly, platelet-derived TGFbeta(1) modulate the systemic inflammatory response occurring after injury.

Inactivation of active and latent transforming growth factor beta by free thiols: Potential redox regulation of biological action

Transforming growth factor-beta (TGF-beta) is a multifunctional cytokine with important roles in inflammation, wound repair, and cancer. Cells secrete TGF-beta as a latent protein complex, consisting of disulfide-bonded homodimers of growth factor and latency-associated propeptide. Latency regulates extracellular TGF-beta action by controlling the levels of active growth factor available. We report here that active and latent TGF-beta were inactivated in vitro by reduction of the growth factor dimer under physiological conditions. We also demonstrate that the latency-associated propeptide has chaperone-like activity and partially protects TGF-beta from inactivation. TGF-beta inactivation occurred upon incubation with the physiological redox agents, cysteine, homocysteine, and reduced glutathione. Inactivation was temperature- and dose-dependent. While inactivation by physiological concentrations of redox agents was partial at 37 degrees C, active and latent TGF-beta were completely inactivated by raising the temperature in the presence of the redox agents. The mechanism of TGF-beta inactivation involved the generation of biologically inactive growth factor monomer and required the presence of free thiol groups, since thiol blockers protected TGF-beta from reduction. We conclude that non-enzymatic redox reactions may be involved in the regulation of extracellular TGF-beta activity. This might be of particular relevance in wound repair (e.g. in burns), as a mechanism protecting from excess TGF-beta activity, as well as in conditions involving redox dysregulation, such as reperfusion injury of the heart, Alzheimer's disease, and cancer.