The significance of changes in serum tumour necrosis factor (TNF) activity in severely burned patients

The Health Hazards of Volcanoes: First Evidence of Neuroinflammation in the Hippocampus of Mice Exposed to Active Volcanic Surroundings

Neuroinflammation is a process related to the onset of neurodegenerative diseases; one of the hallmarks of this process is microglial reactivation and the secretion by these cells of proinflammatory cytokines such as TNFα. Numerous studies report the relationship between neuroinflammatory processes and exposure to anthropogenic air pollutants, but few refer to natural pollutants. Volcanoes are highly inhabited natural sources of environmental pollution that induce changes in the nervous system, such as reactive astrogliosis or the blood-brain barrier breakdown in exposed individuals; however, no neuroinflammatory event has been yet defined. To this purpose, we studied resting microglia, reactive microglia, and TNFα production in the brains of mice chronically exposed to an active volcanic environment on the island of São Miguel (Azores, Portugal). For the first time, we demonstrate a proliferation of microglial cells and an increase in reactive microglia, as well an increase in TNFα secretion, in the central nervous system of individuals exposed to volcanogenic pollutants.

Cardiac Dysfunction in Severely Burned Patients: Current Understanding of Etiology, Pathophysiology, and Treatment

Patients who experience severe burn injuries face a massive inflammatory response resulting in hemodynamic and cardiovascular complications. Even after immediate and appropriate resuscitation, removal of burn eschar and covering of open areas, burn patients remain at high risk for serious morbidity and mortality. As a result of the massive fluid shifts following the initial injury, along with large volume fluid resuscitation, the cardiovascular system is critically affected. Further, increased inflammation, catecholamine surge, and hypermetabolic syndrome impact cardiac dysfunction, which worsens outcomes of burn patients. This review aimed to summarize the current knowledge about the effect of burns on the cardiovascular system.A comprehensive search of the PubMed and Embase databases and manual review of articles involving effects of burns on the cardiovascular system was conducted.Many burn units use multimodal monitors (e.g., transpulmonary thermodilution) to assess hemodynamics and optimize cardiovascular function. Echocardiography is often used for additional evaluations of hemodynamically unstable patients to assess systolic and diastolic function. Due to its noninvasive character, echocardiography can be repeated easily, which allows us to follow patients longitudinally.The use of anabolic and anticatabolic agents has been shown to be beneficial for short- and long-term outcomes of burn survivors. Administration of propranolol (non-selective β-receptor antagonist) or oxandrolone (synthetic testosterone) for up to 12 months post-burn counteracts hypermetabolism during hospital stay and improves cardiac function.A comprehensive understanding of how burns lead to cardiac dysfunction and new therapeutic options could contribute to better outcomes in this patient population.

Leptin and fractalkine: novel subcutaneous cytokines in burn injury

Burn injury is a pathology underpinned by progressive and aberrant inflammation. It is a major clinical challenge to survival and quality of life. Although the complex local and disseminating pathological processes of a burn injury ultimately stem from local tissue damage, to date relatively few studies have attempted to characterise the local inflammatory mediator profile. Here, cytokine content and associated transcriptional changes were measured in rat skin for three hours immediately following induction of a scald-type (60°C, 2 min) burn injury model. Leptin (P=0.0002) and fractalkine (P=0.0478) concentrations were significantly elevated post-burn above pre-burn and control site values, coinciding with the development of burn site oedema and differential expression of leptin mRNA (P=0.0004). Further, gene sequencing enrichment analysis indicated cytokine-cytokine receptor interaction (P=1.45×10-6). Subsequent behavioural studies demonstrated that, following subcutaneous injection into the dorsum of the paw, both leptin and fractalkine induced mechanical allodynia, heat hyperalgesia and the recruitment of macrophages. This is the first report of leptin elevation specifically at the burn site, and the first report of fractalkine elevation in any tissue post-burn which, together with the functional findings, calls for exploration of the influence of these cytokines on pain, inflammation and burn wound progression. In addition, targeting these signalling molecules represents a therapeutic potential as early formative mediators of these pathological processes.

Evaluation of the Treatment Effect of Aloe vera Fermentation in Burn Injury Healing Using a Rat Model

Burn injury is a growing medical problem associated with public health, and few effective agents are available for treatment of this disease. In the present study, a burn injury rat model was developed and the accelerated effect of Aloe vera fermentation on burn injury healing was evaluated. Our results indicated that Aloe vera fermentation could markedly reduce the DPPH (56.12%), O^2·− (93.5%), ^·OH (76.12%), Fe²⁺ chelation (82%), and oxygen-reduction activity (0.28 μg/ml) and significantly inhibited the growth of pathogens S. typhimurium ATCC 13311 (inhibition zone diameter: 14 mm), S. enteritidis ATCC13076 (IZD: 13 mm), S. flexneri ATCC 12022 (IZD: 18 mm), E. coli 44102 (IZD: 10 mm), L. monocytogenes ATCC 19111 (IZD: 18 mm), S. dysenteriae 301 (IZD: 20 mm), S. aureus COWAN1 (IZD: 19 mm), and P. acnes ATCC 11827 (IZD: 25 mm) in vitro. The in vivo results indicated that Aloe vera fermentation produced more eosinophils and fibroblasts and less vessel proliferation compared with the model group on the 14^th day, which had greatly accelerated burn injury healing via shedding of the scab and promoting hair growth. ELISA results indicated that Aloe vera fermentation had significantly reduced the production of proinflammatory factors TNF-α and IL-1β (p < 0.05) and greatly enhanced the yield of anti-inflammatory factor IL-4 in animal serum (p < 0.05). In addition, the high-throughput sequencing results indicated that Aloe vera fermentation obviously increased the percentage of Firmicutes (65.86% vs. 49.76%), while reducing the number of Bacteroidetes (27.60% vs. 45.15%) compared with the M group at the phylum level. At the genus level, Aloe vera fermentation increased the probiotic bacteria Lactobacillus (3.13% vs. 2.09%) and reduced the pathogens Prevotella (10.60% vs.18.24%) and Blautia (2.91% vs. 16.41%) compared with the M group. Therefore, we concluded that the use of Aloe vera fermentation significantly accelerates burn injury healing via reduction of the severity of inflammation and through modification of gut microbiota.

The optimal timing of outpatient Biobrane™ application for superficial and mid dermal partial thickness burns: Evidence for the '12-hour rule'

BACKGROUND

Biobrane™ is a skin substitute used for the definitive management of partial thickness burns. No studies have examined the optimal timing of Biobrane™ application in this setting. The purpose of this study was to determine whether there was a clinically significant difference in applying Biobrane to a superficial and mid dermal partial thickness burn within 12h after burn.

METHODS

From August 2016-February 2017, 29 consecutive superficial and mid dermal partial thickness burn injuries were prospectively treated with Biobrane™ within 12h of the injury. This 'early Biobrane™' cohort was compared to a historical cohort of 148 patients who were treated with Biobrane™ for superficial and mid dermal burns after 12h after injury during 2015 to 2016. Multivariate regression analysis was used to determine the difference in time to re-epithelialisation and number of outpatient visits between the two cohorts.

RESULTS

In the 'early Biobrane™' group, the mean TBSA was 3.5±2.7%. and the mean time to Biobrane™ application was 7.1±2.7h after burn injury. The mean time to re-epithelialisation in this group was 9.1±3.0 days, and no patients underwent skin grafting. In the 'delayed Biobrane™' group, the mean TBSA was 2.6±2.8% and the mean time to Biobrane™ application was 35.1±21.4h. The mean time to re-epithelialisation was 14.8±8.7 days, with 3 patients undergoing skin grafting. Regression analysis demonstrated a statistically significant 63% reduction in time to re-epithelialisation (95% CI=0.23-0.60; P<0.0001) with early Biobrane™ application.

CONCLUSION

Patients treated with application of Biobrane™ within 12h of superficial and mid dermal partial thickness burns have a statistically significant reduction in healing time when compared to patients treated with standard Biobrane™ practice.

Apoptosis in cardiac myocytes during the early stage after severe burn

BACKGROUND

Cardiac dysfunction after severe burn is associated with postburn myocardial injury. We hypothesize that myocyte apoptosis is triggered and presented as the pathologic basis of postburn myocardial injury during the early stage after severe burn, and that apoptosis may be related to inflammatory responses in the postburn myocardium.

METHODS

Rats with 40% total body surface area full-thickness burn were used. The following functions were measured at several time points after the burn injury: myocyte apoptosis (TUNEL staining, DNA ladder, and caspase-3 activity assay); mRNA levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (reverse transcriptase-polymerase chain reaction [RT-PCR]); activities of myeloperoxidase and p38 mitogen activated protein (MAP) kinase (Western blots); and left cardiac function.

RESULTS

TUNEL positive myocytes appeared as early as 6-hour and their numbers showed further increases at 12-hour and 24-hour postburn; DNA fragmentation was clearly observed, and caspase-3 activity was significantly increased in the myocardium after burn. Infiltration of neutrophils, evidenced by the levels of myeloperoxidase activity, expression of TNF-alpha, and p38 MAP kinase activity in the heart, were all significantly increased within 24-hour after burn. Cardiac function was decreased after burn, which approximately paralleled the increased amount of cardiac apoptosis.

CONCLUSION

These results demonstrate that cardiomyocyte apoptosis progressively develops during the early stage after severe burn, which may in part contribute to burn-induced cardiac dysfunction. Myocardial inflammatory responses, evidenced by the increased infiltration of neutrophils, as well as production of TNF-alpha probably because of the activation of p38 MAP kinase, may be involved in burn-induced cardiomyocyte apoptosis.

Lymph invasion route of bacteria and endotoxin and CD4+/CD8+ T cells ratio changes of draining lymph node of burn infection wound

The aim of this study was to determine the lymphatic invasion route of bacteria and endotoxin of burn wounds infected by Pseudomonas aeruginosa and moreover, the effect of P. aeruginosa infection of the burn wound on the draining lymph node and lymph fluid. Male Wistar rats were subjected to unilateral hind limb burn+wound infected by P. aeruginosa (infection limbs group) and contralateral hind limb burn alone (burn limbs group). On hours 6, 24 and 72 after infection, rats were killed, the common iliac lymph nodes (CILN) was collected for the culture of P. aeruginosa. Lymph fluid in the efferent lymph trunk of CILN was collected for the measurement of endotoxin by the Limulus Amebocyte Lysate test. Lymph fluid tumor necrosis factor-alpha (TNF-alpha) concentration was measured by enzyme-linked immunosorbent assay (ELISA). The CD4+/CD8+ T cells ratio of CILN was subjected to flow cytometry analysis. The results showed bacteria invasion incidence, endotoxin and TNF-alpha concentrations were significantly higher in the infection limb group when compared to the burn limb group (P<0.01). The CD4+/CD8+ T cell ratio was significantly lower on post-burn wound infection hours 72 (P<0.05). This study provides evidence that bacteria and endotoxin of burn wound infected by P. aeruginosa invade draining lymph node and lymph fluid. P. aeruginosa infection of the burn wound can increase TNF-alpha level of the draining lymph fluid and decrease CD4+/CD8+ T cells ratio of the draining lymph node.

Thalidomide decreases the plasma levels of IL-1 and TNF following burn injury: is it a new drug for modulation of systemic inflammatory response

TNF and IL-1, which are produced from phagocytic cells, can produce a significant systemic inflammatory response independently by inducing systemic leukocyte and endothelial cell activation. These cytokines play a pivotal role in development of systemic inflammatory response after severe burn. Thalidomide has been shown to decrease the secretion of TNF from phagocytic cells, therefore suppression of TNF and IL-1 production from activated phagocytic cells might be a successful treatment modality for prevention of systemic inflammatory response following severe burn. To address this issue, we aimed to show whether thalidomide treatment decreased or suppressed plasma levels of TNF and IL-1 following burn in rats. Following the injury, 36 rats were randomly separated into two experimental groups at the third and seventh days. Rats in the experimental group had oral thalidomide (10mg/kg day) treatment for three and seven consecutive days whereas animals in control groups had no treatment. Thalidomide treatment decreased TNF and IL-1 significantly in both experimental groups at both the points (P<0.05). Although in this study we just showed inhibitory effect of thalidomide on plasma the level of TNF and IL-1, we speculate that thalidomide may have modulatory effect on the systemic inflammatory response after burn by decreasing plasma levels of TNF and IL-1.

Semapimod Reduces the Depth of Injury Resulting in Enhanced Re-epithelialization of Partial-Thickness Burns in Swine

Studies suggest that tumor necrosis factor alpha (TNF-alpha) plays a role in burn pathogenesis. We conducted a randomized controlled experiment in swine to determine whether a novel macrophage inhibitor, semapimod (formerly known as CNI-1493), would blunt the local production of TNF-alpha, interleukin (IL)-1, and IL-6 in burns leading to less injury extension and faster re-epithelialization. After creating second-degree burns, animals received one or two intravenous boluses of semapimod 1 mg/kg or normal saline, and all burns were treated with silver sulfadiazine. The depth of follicular necrosis and thrombosis was reduced by either one or two doses of semapimod (P=.04 and .02, respectively). However, no differences were noted between groups in cytokine levels. Depth of scarring was similar in all groups. We conclude that Semapimod reduces the depth of follicular necrosis and thrombosis after second-degree burns in swine, indirectly resulting in more rapid re-epithelialization. However, this affect does not appear to be mediated by reduced local TNF-alpha, IL-1, or IL-6 protein levels.

EFFECTS OF BURN SERUM ON MYOCARDIAL INFLAMMATION AND FUNCTION

Large cutaneous burns are clearly recognized to produce acute myocardial contractile dysfunction. This study used a model of burn serum challenge in either primary cardiomyocyte cultures or isolated perfused hearts to examine several aspects of burn-serum-related contractile dysfunction as well as myocardial inflammatory responses. Despite the absence of detectable LPS in burn serum, pretreating isolated cells or perfused hearts with recombinant bactericidal permeability-increasing protein (rBPI21) prevented both the inflammatory cytokine cascade and the cardiac contractile dysfunction induced by burn serum treatment of myocytes or ventricular muscle preparations. Our finding that anti-TNF strategies applied to isolated myocytes or hearts before burn serum challenge prevented myocardial inflammation and contractile dysfunction suggested that LPS or LPS-like factors may require the action of second messengers such as TNF-alpha and IL-1beta to mediate LPS-related myocardial depressant effects. Our finding that experimental approaches neutralizing circulating LPS provided cardioprotection suggested that bacterial endotoxin or LPS-like molecules contribute, in part, to burn-related myocardial contractile dysfunction.

Cytokine induction by the P. aeruginosa quorum sensing system during thermal injury

INTRODUCTION

Pseudomonas aeruginosa causes serious infections in severely burned patients due to its ability to produce numerous virulence factors. The production of most of these factors is controlled by the cell-to-cell communication system called quorum sensing (QS). We have recently shown that several proinflammatory and hematopoietic cytokines are produced during infection of the burn wound with P. aeruginosa strain PAO1. Most of these cytokines were not produced during either thermal injury or P. aeruginosa infection alone.

MATERIALS AND METHODS AND RESULTS

In this study, we tried to determine if the QS systems play a role in the production of cytokines during P. aeruginosa infection of burn wounds. This was accomplished using the murine model of thermal injury, the P. aeruginosa strain PAO1 and its QS defective mutant (PAO-JP2), and the Multi-probe RNase protection assay. The mRNA for TNF-alpha, IL-6, TGF-beta, and G-CSF was detected within the skin of PAO1 infected/thermally injured mice. In contrast, the expression of these cytokines was not detected in PAO-JP2 infected/thermally injured mice. In comparison with the parent strain, PAO-JP2 was not defective either in its growth or in its spread within the thermally injured skin. A complementation experiment, using a plasmid that carries the intact QS gene, was conducted to confirm these results. In the presence of the complementing plasmid, PAO-JP2 produced the mRNA for the above cytokines.

CONCLUSIONS

These results suggest that: 1) the QS system is involved in the induction of cytokine expression during P. aeruginosa infection of burn wounds; and 2) this effect may be caused by either a component of the QS system or a QS-controlled virulence factor.

Myocardial function and haemodynamics in extensive burn trauma: evaluation by clinical signs, invasive monitoring, echocardiography and cytokine concentrations. A prospective clinical study

BACKGROUND

The objectives of this study were to (1). describe the haemodynamic profile of patients with extensive burns during the early fluid resuscitation phase, (2). evaluate myocardial performance by invasive monitoring and echocardiography and (3). analyze the relations between serum cytokine (IL-6, IL-8, TNF) and natriuretic peptide (ANP, BNP) concentrations and myocardial function in these patients.

METHODS

Prospective, clinical study in a tertiary care burn centre. Invasive haemodynamic measurements including a pulmonary artery catheter, echocardiography, blood samples for cytokine and atriopeptide analyses. The follow-up time was up to 72 h postinjury.

RESULTS

According to echocardiography, patients were hypovolaemic despite aggressive (median 7,9 ml kg(-1) h(-1), range 3.3-11.7) fluid resuscitation and adequate urine output (median 0.9 ml kg(-1) h(-1), range 0.46-1.35) during the first day postinjury. There were no consistent findings of hyperlactatemia, metabolic acidosis or low mixed venous oxygen saturations. Daily highest and lowest values of cardiac index and stroke volume index increased and the lowest and highest values of systemic vascular resistance decreased. Cardiac performance (stroke volume index) improved during the study period even though there were no initial signs of myocardial depression in echocardiography. Three patients received a dobutamine infusion based on clinical judgement. There was no consistent association between haemodynamic changes and plasma cytokine concentrations.

CONCLUSION

Persisting hypovolaemia is evident in the resuscitation phase of extensive burns despite aggressive fluid therapy and the lack of classic signs of hypoperfusion. Cardiac performance improves during the first days after extensive burn injury without association with plasma cytokine profile.

Anti-ETA IgG neutralizes the effects of Pseudomonas aeruginosa exotoxin A

BACKGROUND

The opportunistic pathogen Pseudomonas aeruginosa causes severe infections in immunocompromised hosts. Among P. aeruginosa-infected burn patients, mortality may reach as high as 50%. Due to their immunocompromised status, burn patients may benefit from passive immunotherapy against infection. As a potential multivalent immunoglobulin therapy, specific polyclonal antibodies against four P. aeruginosa virulence factors, including exotoxin A (ETA), were prepared.

MATERIALS AND METHODS AND RESULTS

In this study, we analyzed the ability of ETA antibody (ETA-Ab) to neutralize the in vivo effects of ETA. Adult mice injected with purified ETA suffered 100% mortality. The cytosolic DNA of their hepatocytes was fragmented, indicating ETA induction of apoptosis. In addition, multiprobe RNase protection assays showed that ETA upregulates the expression of the genes for proinflammatory cytokines as well as apoptosis genes in the livers of ETA-injected mice. Treatment with ETA-Ab prior to ETA injection prevented mortality, ETA-induced hepatocyte DNA fragmentation, and upregulation of the cytokine and apoptosis-related genes. The role of ETA during P. aeruginosa infection of the burn wound was examined by determining the in vivo virulence of P. aeruginosa PA103 and its isogenic, ETA-deficient mutant PA103Omega::toxA using the thermally injured mouse model. The lethality, local spread, and systemic spread of PA103Omega::toxA were significantly reduced compared to PA103.

CONCLUSION

These results suggest that (1) ETA induces apoptosis in hepatocytes, (2) specific cytokines are produced in response to ETA, (3) ETA-Ab neutralizes these effects, and (4) ETA contributes to the spread of P. aeruginosa during burn wound infection.

[Inflammatory reaction and infection in severe burns]

Major burn injury is a lesion where the inflammatory reaction is exported to the whole body. After a short time of hemodynamic changes, this inflammation is kept by necrotic tissues, persistence of an opened wound, and by the pulmonary and gut reactions. When infection starts, it becomes difficult to distinguish its symptoms among the inflammatory signals. The main point of the care of burn patient consists in trying to control this reaction and the immuno-depression it leads to: early excision and grafts, early enteral nutrition, perfect nursing care. There is no specific medical treatment of this state. The antibiotic use must be well weighed up. Infection is often the trigger of the multiple organ dysfunction which is the way the burn patient dies but is not mandatory.

The effects of infection of thermal injury by Pseudomonas aeruginosa PAO1 on the murine cytokine response

Pseudomonas aeruginosa infection, one of the major complications of burn wounds, may lead to sepsis and death. Using the Multi-Probe Template/RNase protection assay, we have compared the expression of different cytokine genes within the skin and livers of thermally injured mice infected with P. aeruginosa PAO1. Thermal injury alone enhanced or up-regulated certain cytokines, including macrophage colony-stimulating factor (M-CSF), interleukin 1 (IL-1)RI, IL-1 beta, macrophage inflammatory protein (MIP)-1 beta and MIP-2; while PAO1 challenge alone up-regulated tumour necrosis factor alpha (TNF-alpha) and transforming growth factor beta (TGF-beta) expression. The combination of thermal injury plus PAO1 infection enhanced the expression of several pro-inflammatory and haematopoietic cytokines [stem cell factor (SCF), leukocyte inhibitory factor (LIF), IL-6 and TNF-alpha]; induced the expression of granulocyte-macrophage colony-stimulating factor (GM-CSF) and G-CSF by 5 h and the expression of additional cytokines, including TGF-beta, TNF-beta, lymphotoxin beta (LT-beta), interferon gamma (IFN-gamma), and IFN-beta by 40 h post-burn/infection. While the most intense cytokine expression occurred in the skin, the majority of cytokines tested were also expressed in the liver by 40 h post-burn/infection. These results suggest that in P. aeruginosa infection of burn wounds: (1) up-regulation of the expression of different cytokines, locally and within the livers of burned mice, is an indication of P. aeruginosa -induced sepsis; and (2) IL-6 and G-CSF play an important role in the host response mechanism.

Treatment with cerium nitrate bathing modulate systemic leukocyte activation following burn injury: an experimental study in rat cremaster muscle flap

It is suggested that burn toxin known as lipid protein complex (LPC) stimulates phagocytic cells that cause the release of a variety of inflammatory mediators which induce the activation of leukocytes. It is reported that cerium nitrate (CN) might fix LPC in eschar tissue and prevent LPC from entering the circulation. In this study, we tested the hypothesis that prevention or modulation of LPC initiated cell activation by fixing LPC in eschar tissue with CN treatment, would reduce the number of activated leukocytes, which is an important indicator of inflammation, in rat cremaster muscle flap model. Twenty-eight animals were studied in four groups--group I (control), only cremaster muscle flap was dissected; group II (burn injury), burn injury was performed and flap was dissected; group III (saline); and group IV (CN), following burn injury rats treated with saline and CN, respectively, and than flaps were dissected. Blood vessels were observed in vivo under an intravital microscopy system and the number of rolling, sticking, and transmigrating leukocytes were measured in each group. Burn injury significantly increased the number of activated leukocytes (P<0.001). We observed that CN treatment significantly reduced the number of activated leukocytes following burn injury (P<0.001). In conclusion, we demonstrated that CN treatment significantly decreased the activation of leukocytes, which plays an important role in systemic inflammation. Decreased leukocyte activation is interpreted as prevention or modulation of systemic inflammatory response following burn injury.

Apoptotic death of neurons exhibiting peripherin aggregates is mediated by the proinflammatory cytokine tumor necrosis factor-alpha

Peripherin, a neuronal intermediate filament protein associated with axonal spheroids in amyotrophic lateral sclerosis (ALS), induces the selective degeneration of motor neurons when overexpressed in transgenic mice. To further clarify the selectivity and mechanism of peripherin-induced neuronal death, we analyzed the effects of peripherin overexpression in primary neuronal cultures. Peripherin overexpression led to the formation of cytoplasmic protein aggregates and caused the death not only of motor neurons, but also of dorsal root ganglion (DRG) neurons that were cultured from dissociated spinal cords of peripherin transgenic embryos. Apoptosis of DRG neurons containing peripherin aggregates was dependent on the proinflammatory central nervous system environment of spinal cultures, rich in activated microglia, and required TNF-alpha. This synergistic proapoptotic effect may contribute to neuronal selectivity in ALS.

The relationship between tumor necrosis factor (TNF)-alpha and survival following granulocyte-colony stimulating factor (G-CSF) administration in burn sepsis

Blood levels of tumor necrosis factor (TNF)-alpha were determined in 78 patients with burn sepsis. Of these patients, 51 were managed with additional administration of granulocyte colony-stimulating factor (G-CSF) in addition to routine treatment procedures (group A), while 27 received only routine treatment (group B). G-CSF was administrated for at least nine and at most 14 days; doses were gradually decreased in each 3 day period. On the 1st, 4th, 7th, 10th and 15th days, blood levels of TNF-alpha were determined. We sought to determine whether TNF alpha levels had a prognostic value in the management of burn induced sepsis that was treated with G-CSF. In our study, patients with gradually decreasing TNF-alpha levels in the second 3 day period, were strong candidates for survival, because TNF-alpha levels decreased little in nonsurvivors but decreased greatly in survivors. The survival rate was 42/51 (82.3%) in group A and 9/27 (33.3%) in group B. In conclusion, G-CSF had positive effects on survival, and TNF-alpha was a predictor of prognosis in burn-induced sepsis.

The effect of severe burn injury on proinflammatory cytokines and leukocyte behavior: its modulation with granulocyte colony-stimulating factor

Severe injury causes immunosuppression. The main contributors are impaired leukocyte function and a cytokine dysbalance. GCSF increases PMN count, function and modulates the inflammatory response. However GCSF may overactivate leukocytes. The purpose of this study is to investigate whether GCSF is able to restore immune competence after severe injury. Lewis rats were divided into three groups: 30% TBSA burn + vehicle; 30% TBSA burn + GCSF (150 microg rhGCSF); Control. Blood samples were taken for total white cell count, PMNs, TNFalpha and IFNgamma. Leukocyte rolling and sticking were measured in the cremaster muscle microcirculation. Leukocyte diapedesis was investigated by lavage of the abdominal cavity and the lungs. Total white cell and PMN counts in the burn + GCSF group were significantly higher (P<0.001) than in burn+vehicle animals. Leukocyte adherence and diapedesis were not elevated in the burn + GCSF group as compared to the burn + vehicle group. TNFalpha (P<0.05) and IFNgamma (P<0.001) levels were significantly increased in the burn + vehicle animals compared to the burn + GCSF animals. GCSF modifies the immune system, as shown by an increase in white cell and PMN counts and by balancing the overall immune response from proinflammatory to normal, as shown by decreased TNFalpha and IFNgamma levels. GCSF does not overactivate PMNs.

Changes in circulating levels of interleukin 6 in burned patients

Interleukin 6 (IL-6) levels in serial serum samples of 10 burned patients were analyzed. The total body surface areas (TBSA) of the burn injury varied from 30 to 85%. Among these 10 patients, five recovered and the other five, who were septic, expired. A significant difference in serum IL-6 values on admission (5-13 h postburn) was found (p < 0.05) between patients who survived or died from burn injury as analyzed by the Wilcoxon's rank sum test. In addition, a significant difference in serum IL-6 on admission was also found (p < 0.05) between patients with TBSA of greater or less than 50%. Afterwards, an initial peak serum IL-6 response was detected within 4 days postburn. Significant differences in the peak serum IL-6 levels were not found between patients with TBSA of greater or less than 50% and patients who survived or expired from burn injury. In the survivors, serum IL-6 remained low, while IL-6 increased markedly starting at about one to two weeks postburn in four of the five nonsurvivors with proven sepsis. Except for the patient who expired 42 days postburn, the maximum serum IL-6 values of the other four nonsurvivors were all greater than those of the five survivors from burn injury. Significant correlation (p < 0.05) relating the change in serum IL-6 and body temperature was observed in only two (one survivor and one nonsurvivor) of the ten patients. Changes in serum IL-6 were also compared with changes in circulating TNF-alpha and IL-8 determined previously. A similar pattern in the dynamic changes of circulating TNF-alpha, IL-8 and IL-6 was observed in the individual burned patient. An increase in serum levels of all three cytokines was detected postburn. Serum levels of three cytokines were significantly higher in the septic patients, who all died. It was considered that all three cytokines analyzed may play a significant role in the pathophysiology of sepsis in burned patients.

Changes in serum tumour necrosis factor-alpha in burned patients

Dynamic tumour necrosis factor-alpha (TNF-alpha) changes in serial serum samples of 10 burned patients were analysed in this study. The total body surface areas (TBSA) of the burn injury were from 30 to 85 per cent. Among these 10 patients, five recovered and another five died with proved sepsis. On admission which was about 5-13 h postburn, eight of the 10 patients showed their serum TNF-alpha levels to be higher than the mean serum TNF-alpha value of five healthy laboratory personnel. Furthermore, an initial peak serum TNF-alpha response which could be detected within 2.5 days after burn injury has also been observed. However, significant differences in both the serum TNF-alpha values on admission, as well as the first peak serum TNF-alpha levels, were not found (P > 0.05) between patients with TBSA of greater or less than 50 per cent and patients who survived or died from burn injury. In the survivors, serum TNF-alpha stayed at low levels, while it increased markedly in four of the five non-survivors with proven sepsis starting at about 1 week postburn. A significant difference in the maximum serum TNF-alpha levels (P < 0.05) was detected between patients who recovered and died from the thermal injury. In conclusion, great increases in serum TNF-alpha levels have been detected in burned patients with the occurrence of bacterial infection postburn. It is suggested that strategies for the inhibition of TNF-alpha production or in the neutralization of TNF-alpha activity should also be considered in the better treatment of burned patients.

Subcapsular hematoma of the liver and pylethrombosis in the setting of cholestatic liver injury

We describe a subcapsular hematoma of the liver and pylethrombosis in a patient who developed cholestasis 4 days after severe burn injury. On the 44th hospital day, severe anemia suddenly appeared with no determinable cause. This was the initial manifestation of hepatic hematoma. Cholestatic liver injury of unknown cause lasted throughout the clinical course. The patient subsequently died of hepatic failure 27 months after the burn injury. An autopsy confirmed pylephlebitis and pylethrombosis, which were considered to have contributed to the hepatic failure. This was a rare case of hepatic hematoma and pylephlebitis and pylethrombosis that developed after burn injury.

Plasma cytokine levels in patients with severe burn injury--with reference to the relationship between infection and prognosis

Blood levels of various cytokines were determined in patients with burn injury immediately after the accident, and the relationship between cytokines and morbid condition was investigated. There was almost no marked elevation of cytokines in the early stage of burn injury. Throughout the entire course, tumour necrosis factor alpha, interleukin 6 and interleukin 8, as cytokines, showed high levels in patients with burn injury associated with sepsis and those who died. These levels well reflected the severity in the phase complicated with sepsis.

Pathophysiology of the burn wound and pharmacological treatment. The Rudi Hermans Lecture, 1995

The body's reaction to thermal injury is much more than an initial, local inflammatory response. The burn wound is a continuous, severe threat against the rest of the body due to invasion of infectious agents, antigen challenge and repeated additional trauma caused by wound cleaning and excision. The inflammatory mediators which control blood supply and microvascular permeability in the wound have been extensively studied and are largely understood. Attempts to suppress the inflammatory reaction by different drugs, have, however, been less successful. Extensive thermal injury and sepsis also results in immunosuppression. The defects causing immunosuppression are still very much under consideration. An understanding of these defects is essential for the development of therapies. The increasing interest in the control of the inflammatory reactions by cytokines may, in the near future, be of great importance.

[Severe burnt patients: hemodynamic state, oxygen transport and consumption, plasma cytokines]

OBJECTIVE

To assess the haemodynamic and oxymetric variations measured by a pulmonary artery catheter and to correlate them with the variations of the circulating cytokines during the initial intensive care phase of severely burned patients.

STUDY DESIGN

Prospective study covering an 18-month period.

PATIENTS

Thirteen successive patients, aged over 12 years, without significant medical history, with a thermal burn affecting more than 50 percent of their total body surface area and admitted to our centre during the first six postburn hours.

METHODS

The haemodynamic and oxymetric profile was investigated by inserting a blood flow-directed balloon-tipped pulmonary artery fiberoptical catheter. All patients were treated according to the protocol previously used in our centre. Blood samples were drawn on admission, every 12 hours post-injury until the 2nd day, then on the 3rd and 5th days. Cytokines were analyzed by Elisa method. Haemodynamic and oxymetric measurements were achieved simultaneously with the biological samples during the first 5 postburn days. The analysis of variance (ANOVA) with the Duncan test was utilized for multiple comparisons between continuous variables.

RESULTS

(mean +/- SEM): The patients were 32 +/- 3 years-old and had a burn surface of 72 +/- 4%. After a short hypovolemic shock period lasting a 12 hours, a hyperdynamic shock occured which increased until the 5th day, with an increased cardiac index (6.9 +/- 0.4 at h120 vs 2.9 +/- 0.3 L.min-1.m-2 at h6, P < 0.05), increased oxygen transport and consumption (respectively 880 +/- 77 at h72 vs 543 +/- 58 mL.min-1 at h12, P < 0.05 and, 203 +/- 15 at h72 vs 129 +/- 25 mL.min-1 at h6, P < 0.05) and markedly decreased systemic vascular resistances (1,002 +/- 118 at h36 vs 2,330 +/- 328 dyn.s.cm-5.m2 at h6, P < 0.05). Circulating cytokines were not clearly modified except for interleukine-6 which reached early striking peaks (16,858 +/- 10,330 at h24 and 15,406 +/- 6,509 pg.mL-1 at h36) simultaneously with the decrease in systemic vascular resistances.

CONCLUSIONS

During the first post-injury week, critically burned patients develop a specific hyperdynamic circulatory status during which interleukine-6 could be a mainfactor decreasing systemic arterial resistances.

Clinical significance of the change of blood monocytic interleukin-1 production in vitro in severely burned patients

Biological methods were employed to measure the dynamic changes in the in vitro IL-1 production by blood monocytes in 24 severely burned patients. The serum myocardial and hepatic enzymes (C-reactive protein) (CRP), plasma lactic acid (LA), etc. were simultaneously measured. The results showed an obvious decrease in blood monocyte IL-1 production in vitro and increases in CRP, LA and serum enzymes. These changes were more evident in patients complicated with organ injury, multiorgan failure and systemic infection. It is suggested that blood monocytes are superstimulated postburn in vivo and produced large amounts of IL-1 leading to exhaustion of monocyte function. These changes might promote the development of severe systemic infection and internal organ injury even multiple organ failure.