Urinary cortisol and catecholamine excretion after burn injury in children

INTRODUCTION

A severe burn causes increased levels of urine cortisol and catecholamines. However, little is known about the magnitude of this increase or how and when the levels return to normal. The purpose of this study was to determine in a large clinical prospective trial the acute and long-term pattern of urine cortisol and catecholamine expression in severely burned children.

METHODS

Pediatric patients with burns greater than 40% total body surface area (TBSA), admitted to our unit over a 6-yr period, were included into the study. Clinical data including length of stay, number of operations, and duration and number of infections were determined. Patients had regular 24-h urine collections during their acute admission and reconstructive periods. Urine collections were analyzed for cortisol, epinephrine, and norepinephrine. Each urine cortisol was compared with age-adjusted reference ranges. Ninety-five percent confidence intervals and ANOVA analysis were used where appropriate.

RESULTS

Two hundred twelve patients were included in the study (75 females and 137 males), with a mean +/- sem TBSA of 58 +/- 1% (third-degree 45 +/- 2%) and mean age of 9 +/- 0.4 yr. Urinary cortisol levels were significantly increased (3- to 5-fold) up to 100 d after the burn and then approached normal levels (P < 0.05). The rise in urine cortisol was significantly higher in male than female patients (P < 0.05). Early hypercortisolemia was associated with increased duration of severe infection (P < 0.05). Persistent hypercortisolemia was associated with increases in both infection rates and duration of severe infection (P < 0.05). Urinary catecholamines showed a significant increase at 11-20 d after the burn (P < 0.05). Urinary norepinephrine levels were significantly increased up to 20 d and then returned to normal (P < 0.05).

CONCLUSIONS

Urinary levels of cortisol, epinephrine, and norepinephrine are significantly increased after a major burn. Early hypercortisolemia is associated with increased duration of severe infection. Persistent hypercortisolemia is associated with increases in both infection rates and duration of severe infection.

Burn size determines the inflammatory and hypermetabolic response

Background

Increased burn size leads to increased mortality of burned patients. Whether mortality is due to inflammation, hypermetabolism or other pathophysiologic contributing factors is not entirely determined. The purpose of the present study was to determine in a large prospective clinical trial whether different burn sizes are associated with differences in inflammation, body composition, protein synthesis, or organ function.

Methods

Pediatric burned patients were divided into four burn size groups: <40% total body surface area (TBSA) burn, 40–59% TBSA burn, 60–79% TBSA burn, and >80% TBSA burn. Demographic and clinical data, hypermetabolism, the inflammatory response, body composition, the muscle protein net balance, serum and urine hormones and proteins, and cardiac function and changes in liver size were determined.

Results

One hundred and eighty-nine pediatric patients of similar age and gender distribution were included in the study (<40% TBSA burn, n = 43; 40–59% TBSA burn, n = 79; 60–79% TBSA burn, n = 46; >80% TBSA burn, n = 21). Patients with larger burns had more operations, a greater incidence of infections and sepsis, and higher mortality rates compared with the other groups (P < 0.05). The percentage predicted resting energy expenditure was highest in the >80% TBSA group, followed by the 60–79% TBSA burn group (P < 0.05). Children with >80% burns lost the most body weight, lean body mass, muscle protein and bone mineral content (P < 0.05). The urine cortisol concentration was highest in the 80–99% and 60–79% TBSA burn groups, associated with significant myocardial depression and increased change in liver size (P < 0.05). The cytokine profile showed distinct differences in expression of IL-8, TNF, IL-6, IL-12p70, monocyte chemoattractant protein-1 and granulocyte–macrophage colony-stimulating factor (P < 0.05).

Conclusion

Morbidity and mortality in burned patients is burn size dependent, starts at a 60% TBSA burn and is due to an increased hypermetabolic and inflammatory reaction, along with impaired cardiac function.

Insulin decreases inflammatory signal transcription factor expression in primary human liver cells after LPS challenge

Hepatic homeostasis is essential for survival in critically ill and burned patients. Insulin administration improves survival and decreases infections in these patients. To determine the molecular mechanisms, the aim of the present study was to establish a stress model using primary human hepatocytes (PHHs) and to study the effects of insulin on the hepatic inflammatory signaling cascade. Liver tissue was obtained from general surgical patients, and PHHs were isolated and maintained in culture. Primary hepatocyte cultures were challenged with various doses of lipopolysaccharide (LPS), and the inflammatory signal transcription cascade was determined by real-time PCR. In subsequent experiments, primary hepatocyte cultures were challenged with LPS and insulin was added in various doses. Glucose was determined by colorimetric assays. PHHs treated with 100 microg/mL LPS showed a profound inflammatory reaction with increased expression of interleukin (IL)-6, IL-10, IL-1beta, tumor necrosis factor (TNF), and signal transducer and activator of transcription 5 (STAT-5). Insulin at 10 IU/mL significantly decreased IL-6, TNF, and IL-1beta at pretranslational levels, an effect associated with decreased STAT-5 mRNA expression (P < 0.05). Glucose concentration and cellular metabolic activity were not different between controls and insulin-treated cells. Based on our results, we suggest that primary hepatocyte cultures can be used to study the effect of LPS on the inflammatory cascade. Insulin decreases hepatic cytokine expression, which is associated with decreased STAT-5 expression.

Age differences in inflammatory and hypermetabolic postburn responses

OBJECTIVE

The aim of this study was to identify contributors to morbidity and death in severely burned patients <4 years of age.

METHODS

A total of 188 severely burned pediatric patients were divided into 3 age groups (0-3.9 years, 4-9.9 years, and 10-18 years of age). Resting energy expenditure was measured through oxygen consumption, body composition through dual-energy x-ray absorptiometry, liver size and cardiac function through ultrasonography, and levels of inflammatory markers, hormones, and acute-phase proteins through laboratory chemistry assays.

RESULTS

Resting energy expenditure was highest in the 10- to 18-year-old group, followed by the 4- to 9.9-year-old group, and was lowest in the 0- to 3.9-year-old group. Children 0 to 3.9 years of age maintained lean body mass and body weight during acute hospitalization, whereas children >4 years of age lost body weight and lean body mass. The inflammatory cytokine profile showed no differences between the 3 age groups, whereas liver size increased significantly in the 10- to 18-year-old group and was lowest in the 0- to 3.9-year-old group. Acute-phase protein and cortisol levels were significantly decreased in the toddler group, compared with the older children. Cardiac data indicated increased cardiac work and impaired function in the toddler group, compared with the other 2 age groups.

CONCLUSIONS

Increased mortality rates for young children are associated with increased cardiac work and impaired cardiac function but not with the inflammatory and hypermetabolic responses.

Longitudinal assessment of Integra in primary burn management: A randomized pediatric clinical trial*

BACKGROUND

Early excision with autograft-allograft closure is standard in severe burn management. Cadaver skin is associated with risks such as antigenicity, infection, and limited availability and shelf life. Previous studies have shown that Integra is safe to use in burns of <20% total body surface area. However, the suitability of its use in large burns (>50% total body surface area), its effects on postburn hypermetabolism, and the long-term cosmetic and functional results have not yet been evaluated.

MATERIALS AND METHODS

Twenty children with an average burn size of 73 +/- 15% total body surface area (71 +/- 15% full-thickness burn) were randomized to be treated with either Integra or with autograft-allograft technique. Outcome measures such as length of hospital stay, mortality, incidence of infection and sepsis, acute phase protein levels, and muscle fractional synthetic rate were compared between and within groups during the acute stay (admission to discharge). Outcome measures such as resting energy expenditure, body composition data (measured by dual-energy radiograph absorptiometry), cardiac function indexes, and number of reconstructive procedures were compared during acute hospital stay and at long-term follow-up (up to 2 yrs postinjury). Scar evaluation was performed at long-term follow-up.

RESULTS

There were no significant differences between Integra and controls in burn size (70 +/- 5% vs. 74 +/- 4% total body surface area), mortality (40% vs. 30%), and length of stay (41 +/- 4 vs. 39 +/- 4 days). In the short term, resting energy expenditure significantly decreased (p < .01), and serum levels of constitutive proteins significantly increased (p < .03) in the Integra group compared with controls. Long-term follow-up revealed a significant increase in bone mineral content and density (24 months postburn, p < .05), as well as improved scarring in terms of height, thickness, vascularity, and pigmentation (12 months and 18-24 months, p < .01) in the Integra group.

CONCLUSION

Integra can be used for immediate wound coverage in children with severe burns without the associated risks of cadaver skin.

Amnion in the treatment of pediatric partial-thickness facial burns

BACKGROUND

Wound coverage for second-degree burns remains a clinical challenge. Human amniotic membranes have been used for many years in the treatment of burns; however, no large prospective clinical trials have been published. In this article, we present a novel and standardized procurement and processing method for amnion and investigate, whether the use of this biological dressing is safe and may represent a new therapeutic option for children with partial-thickness facial burns compared to standard topical treatment.

METHODS

Patients with partial-thickness burns of the face, neck and head admitted between 2003 and 2005 were included in this study. They were divided into two groups to receive either amnion (n=53) or topical antimicrobials (n=49). Demographics (age, gender, ethnicity, TBSA, burn areas), length of hospital stay (LOS), rate of infections (RI), time to total healing, and frequency of dressing changes were compared between the two groups. The long-term outcome was assessed in nine patients in the amnion group and eight patients in the topical group, who returned for up to 12-month follow-up visits.

RESULTS

Patients in the amnion group had significantly less dressing changes then in the control group (p<0.05). Time to healing, length of stay and the development of hypertrophic scarring was not different between the groups. Use of amnion was not associated with an increased risk of local infection.

CONCLUSION

This study indicates that amnion is safe and has advantages as wound coverage for second-degree facial burns compared to the standard topical ointments. Further studies with the use of amniotic membranes on the trunk and the extremities, as well as for coverage of grafted third-degree burns, have yet to be performed.

The effect of oxandrolone on the endocrinologic, inflammatory, and hypermetabolic responses during the acute phase postburn

OBJECTIVE AND SUMMARY BACKGROUND DATA

Postburn long-term oxandrolone treatment improves hypermetabolism and body composition. The effects of oxandrolone on clinical outcome, body composition, endocrine system, and inflammation during the acute phase postburn in a large prospective randomized single-center trial have not been studied.

METHODS

Burned children (n = 235) with >40% total body surface area burn were randomized (block randomization 4:1) to receive standard burn care (control, n = 190) or standard burn care plus oxandrolone for at least 7 days (oxandrolone 0.1 mg/kg body weight q.12 hours p.o, n = 45). Clinical parameters, body composition, serum hormones, and cytokine expression profiles were measured throughout acute hospitalization. Statistical analysis was performed by Student t test, or ANOVA followed by Bonferroni correction with significance accepted at P < 0.05.

RESULTS

Demographics and clinical data were similar in both groups. Length of intensive care unit stay was significantly decreased in oxandrolone-treated patients (0.48 +/- 0.02 days/% burn) compared with controls (0.56 +/- 0.02 days/% burn), (P < 0.05). Control patients lost 8 +/- 1% of their lean body mass (LBM), whereas oxandrolone-treated patients had preserved LBM (+9 +/- 4%), P < 0.05. Oxandrolone significantly increased serum prealbumin, total protein, testosterone, and AST/ALT, whereas it significantly decreased alpha2-macroglobulin and complement C3, P < 0.05. Oxandrolone did not adversely affect the endocrine and inflammatory response as we found no significant differences in the hormone panels and cytokine expression profiles.

CONCLUSIONS

In this large prospective, double-blinded, randomized single-center study, oxandrolone shortened length of acute hospital stay, maintained LBM, improved body composition and hepatic protein synthesis while having no adverse effects on the endocrine axis postburn, but was associated with an increase in AST and ALT.

Changes in liver function and size after a severe thermal injury

Hepatic homeostasis and metabolism are essential for survival in critically ill and severely burned patients. There is evidence that the liver undergoes hypertrophy after burn. However, the extension and the duration of liver enlargement are not known. The aim of the present study was to determine the changes in liver size, weight, and hepatic protein synthesis in a large prospective clinical trial throughout acute hospitalization and up to 12 months after burn. Liver size was measured by means of ultrasound, and liver weight was calculated weekly during short-term hospital stay and at 6, 9, and 12 months after burn. The liver size was then compared with the predicted liver size for each individual. The levels of hepatic proteins and enzymes were determined by using standard laboratory techniques. One hundred two children were included in the study, with 58% +/- 2% total body surface area and 45% +/- 2% third-degree burn. Liver size and weight significantly increased during the first week after burn (mean +/- SEM, 85% +/- 5%), peaked at 2 weeks after burn (mean +/- SEM, 126% +/- 19%), and, at discharge, increased by 89% +/- 10%. At 6, 9, and 12 months, the liver weight increased by 40% to 50% compared with the predicted liver weight. The hepatic protein synthesis was affected up to 9 months after burn. The liver demonstrates a significant enlargement during short-term hospitalization, accompanied with impairment in the hepatic protein synthesis. The treatment to prevent liver enlargement and the improved impaired function may result in a reduction of complications accompanied with liver hypertrophy and failure.

Metabolism modulators in sepsis: Propranolol

Sepsis is accompanied by an enormous increase in catecholamine expression, leading to metabolism of lipids and glucose, changes in cardiovascular output, immunomodulatory effects, and changes in protein metabolism, all of which push the body into a catabolic state. Deleterious beta-adrenoceptor controlled responses to stress and sepsis are well documented; therefore, it would seem appropriate to use propranolol under such circumstances. There are arguments both for and against the use of beta-adrenoceptor blockade during episodes of stress and infection. The definition of sepsis itself is a clinical one in most cases. There are guidelines concerning the diagnosis of sepsis (systemic inflammatory response syndrome [SIRS] in the presence of significant infection). However, when the cause of SIRS is not infection, for example, in burn patients, is it not possible, and indeed preferable, to tackle the stress response in a more aggressive fashion? The effects of SIRS on the body are myriad and have been defined and illustrated in many fine reviews. The effects of sepsis on the body, as well, have been discussed in the world literature and are beyond the scope of this article. In this article we attempt to demonstrate the effects of sepsis (SIRS plus infection) on whole body metabolism, outline the mediators of these changes, and then show the ability of propranolol to attenuate the changes seen.

Effect of insulin on the inflammatory and acute phase response after burn injury

After a severe burn, the liver plays a pivotal role by modulating inflammatory processes, metabolic pathways, immune functions, and the acute phase response. Therefore, liver integrity and function are important for recovery. A thermal injury, however, causes hepatic damage by inducing hepatic edema, fatty infiltration, hepatocyte apoptosis, and metabolic derangements associated with insulin resistance and impaired insulin signaling. In preliminary studies, we found that these pathophysiological processes are related to hepatic inflammation, altered intracellular signaling, and mitochondrial dysfunction. We hypothesize that modulation of these processes with insulin could improve hepatic structure and function and, therefore, outcome of burned and critically ill patients. Insulin administration improves survival and decreases the rate of infections in severely burned and critically ill patients. Here, we show that insulin administration decreases the synthesis of proinflammatory cytokines and signal transcription factors and improves hepatic structure and function after a severe burn injury; insulin also restores hepatic homeostasis and improves hepatic dysfunction postburn via alterations in the signaling cascade.

Insulin attenuates apoptosis and exerts anti-inflammatory effects in endotoxemic human macrophages

BACKGROUND

Insulin decreases the incidence of sepsis and improves mortality of critically ill patients. In endotoxemic as well as in thermally injured rats, insulin attenuates the systemic inflammatory response by decreasing the proinflammatory and increasing the antiinflammatory cascade. The aim of the present study was to determine the effects of insulin on cell survival, cell activity, apoptosis, and proinflammatory response in a human macrophage-like cell line (THP-1 cells) stressed with lipopolysaccharide (LPS).

MATERIALS AND METHODS

Human macrophages were stressed with LPS and received either saline or insulin. Cell viability was analyzed by MTS, apoptosis was detected using JC-1 and terminal deoxynucleotidyl transferase-mediated nick end labeling-staining, and to elucidate on the signaling pathway, we used wortmannin as a phosphatidylinositol-3-kinase inhibitor. Tumor necrosis factor (TNF) and interleukin-1beta (IL-1beta) were measured to determine the effect of insulin on proinflammatory cytokine expression.

RESULTS

Insulin caused a significant increase in cell viability and significantly reduced apoptosis in LPS-stimulated human macrophages in a dose-dependent manner. The antiapoptotic effect of insulin could be completely blocked with the addition of wortmannin. Insulin significantly decreased TNF and IL-1beta in endotoxemic human macrophages.

CONCLUSIONS

Our results indicate that insulin exerts antiapoptotic effects and reduces the expression of proinflammatory cytokines in endotoxemic human macrophages. The antiapoptotic effects are mediated via the phospatidylinositol-3-kinase-pathway.

The combination of IGF-I and KGF cDNA improves dermal and epidermal regeneration by increased VEGF expression and neovascularization

Insulin-like growth factor-I (IGF-I) and keratinocyte growth factor (KGF) cDNA gene transfer individually improves dermal and epidermal regeneration. The aim of the present study was to determine whether the combination of IGF-I plus KGF cDNA further improves wound healing and by which mechanisms these changes occur. Rats received an acute wound and were divided into four groups to receive weekly subcutaneous injections of liposomes plus Lac Z cDNA, liposomes plus IGF-I cDNA, liposomes plus KGF cDNA, or liposomes plus IGF-I/KGF cDNA. Planimetry, immunological assays, histological and immunohistochemical techniques were used to determine IGF-I, KGF, platelet-derived growth factor, fibroblast growth factor (FGF), transforming growth factor-beta and vascular endothelial growth factor (VEGF) expression and different types of collagen (I, III and IV). IGF-I, KGF and their combination cDNA treatment significantly (P<0.05) accelerated re-epithelization, increased IGF-I, KGF, FGF, VEGF and collagen type IV expression, while it had no effect on collagen type I and III expression. The combination of IGF-I plus KGF cDNA increased (P<0.05) neovascularization and VEGF expression when compared to IGF-I cDNA, KGF cDNA groups and controls. In conclusion, exogenous administration of liposomal IGF-I plus KGF cDNA enhanced dermal and epidermal regeneration which is due to increased neovascularization.

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.

Propranolol does not increase inflammation, sepsis, or infectious episodes in severely burned children

BACKGROUND

Propranolol, a nonselective beta1-2 antagonist, attenuates hypermetabolism and catabolism in severely burned patients. However, recent data suggest that propranolol impairs immune function and enhances inflammation. The purpose of the present study was to determine the effect of propranolol administration on infection, sepsis, and inflammation in severely burned pediatric patients.

PATIENTS

A prospective, intent-to-treat study was performed; patient demographics (age, gender, burn size, and mortality); infectious episodes (colony count greater then 10); and sepsis (guidelines by the society of critical care medicine) were determined. Hypermetabolic response was determined by resting energy expenditure (REE), and the inflammatory response was determined by measuring serum cytokine expression.

RESULTS

Two hundred forty-five patients (143 controls, 102 propranolol) were included into the study. There were no differences between the control and propranolol groups for age, gender distribution, burn size, third degree burn, and length of stay. Mortality was 6% in the control group and 5% in the propranolol group. Propranolol significantly decreased REE and predicted REE during acute hospital stay. Forty-three patients developed infections in the control group (30%), whereas 21 developed infections in the propranolol group (21%). The incidence of sepsis was 10% for controls and 7% for propranolol. Analysis of the cytokine expression profile in 20 patients in each group revealed that propranolol significantly decreased serum tumor necrosis factor and interleukin-1beta compared with controls (p < 0.05).

CONCLUSION

Propranolol treatment attenuates hypermetabolism and does not cause increased incidence of infection and sepsis.

SEX DIFFERENCES IN THE LONG-TERM OUTCOME AFTER A SEVERE THERMAL INJURY

We have recently shown that during the acute phase, postburn female pediatric burn patients had significantly increased levels of anabolic hormones with an associated decreased hypermetabolism leading to a significant shorter intensive care unit stay compared with male patients. The aim of the present study was to determine possible differences between girls and boys in body composition, hypermetabolism, and hormone pattern in the long term. Sixty-two children (1-16 years old) who sustained a severe thermal injury (>or=40% total body surface area) were included into the study. Patients were further divided into girls (n = 22) and boys (n = 40). Patient demographics, nutritional support, and mortality were noted. Resting energy expenditure (REE) was measured by indirect calorimetry, body composition by dual-energy x-ray absorptiometry (Hologic Inc, Waltham, Mass) at discharge, 3, 6, 9, 12, 18, and 24 months after burn. In addition, blood was drawn at the same time points, and serum hormones were measured. There were no significant differences between girls and boys for demographics, nutritional intake, or concomitant injuries. Predicted REE was significantly decreased in girls at discharge, 6, 12, and 18 months postburn (P < 0.05). Dual-energy x-ray absorptiometry scan showed that girls had improved change in bone mineral content and percent fat compared with boys (P < 0.05). There were no differences in changes in height, body weight, lean body mass, and total fat between groups. Girls had significantly higher levels of insulinlike growth factor 1, insulinlike growth factor binding protein 3, free thyroxine index, T4, and insulin when compared with boys (P < 0.05). No differences were found for T3 uptake, osteocalcin, cortisol, growth hormone, and parathyroid hormone (PTH) between groups. Data indicate that girls have a reduced REE associated with changes in bone content and endogenous anabolic hormones.

Insulin attenuates the cytokine response in a burn wound infection model

A massive burn is one of the most serious injuries resulting in major imbalances of the immune system. The aftermath of a burn is frequently complicated by infections and septic events that additionally increase mortality and morbidity. The aim of the present study was to investigate if insulin attenuates the cytokine response of burned mice challenged with Pseudomonas. Male mice (C57/BL/6) received a full thickness burn of 35% of their total body surface area. Mice received 5 IU/kg insulin i.p. or an equal volume of saline for 5 days after burn. Mice were challenged with 5x10 colony forming units Pseudomonas aeruginosa intraperitoneally. Serum was harvested 6 h after the bacterial challenge, and 18 serum cytokines were measured using the Bio-Plex suspension array system (Bio-Rad, Hercules, Calif). All 18 cytokines were elevated after the Pseudomonas challenge. However, mice treated with insulin showed significantly lower proinflammatory cytokine concentrations of interleukin 5, interleukin 6, and keratinocyte-derived chemokine after the Pseudomonas infection when compared with placebo-treated mice (P<0.05). In contrast, serum concentrations of G-CSF were significantly higher in insulin-treated animals when compared with placebo (P<0.05). We conclude, that insulin treatment selectively modulates specific cytokines in a burn wound infection model.

Heat stress modulates hepatocyte membrane proteins during endotoxemia

BACKGROUND

Hepatic failure following sepsis is one of the important features of burns. Studies have shown that in septic rats, heat stress (HS) has a protective effect on bile acid transporters in hepatocyte membranes. This study investigates the influence of HS on hepatocyte membrane proteins during endotoxemia using 2D gel electrophoresis.

METHODS

Endotoxemia in rats was induced by intraperitoneal injection of Escherichia coli lipopolysaccharide (LPS) (n=24), while control rats (n=24) received saline. Twelve rats from each group were exposed to HS 2h prior to LPS or saline injection by external warming to 42 degrees C for 10 min and 12 rats in each group were exposed to ambient temperature 2h prior to LPS or saline injection. Membrane fractions were extracted 12, 24 and 72 h after LPS or saline treatment. Extracted proteins were separated using 2D gel electrophoresis. The most dominant spots were analyzed by MALDI-TOF-MS.

RESULTS

Two-dimensional gel electrophoresis differentially identified expressed proteins in all treatment groups. The majority of the spots developed 24h after injection. Membrane proteins; Wnt 13, ribosomal protein L14, VLCAD, BHMT and HIT-40 were found only in HS-LPS. Protein profiles of the groups returned to normal after 72 h.

CONCLUSION

We propose that HS during endotoxemia changes hepatic membrane proteins expression, which are involved in metabolism.

Blood transfusions are associated with increased risk for development of sepsis in severely burned pediatric patients

OBJECTIVE

To determine the risk of developing sepsis following transfusion of blood products in severely burned pediatric patients.

DESIGN

Retrospective, cohort study.

SETTING

Shriners Hospital for Children and University Hospital.

PATIENTS

Severely burned pediatric patients with >30% total body surface area (TBSA) burn.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred seventy-seven pediatric burn patients over a period of 7 yrs (1997-2004) were included in the study, with 25 patients being septic at admission and therefore excluded. Patients were stratified according to TBSA burn and presence or absence of inhalation injury. The amounts of packed red blood cells (RBCs) and fresh frozen plasma (FFP) were recorded during hospital stay before the development of sepsis. Blood product administration was normalized for the number of surgeries and divided into two groups: high (RBCs>20/FFP>5) or low (RBCs<20/FFP<5) amount of blood products. Sepsis was diagnosed based on the criteria set by the Society of Critical Care Medicine in conjunction with positive blood culture or presence of organisms in the organs at autopsy. By stratifying the groups into low and high blood transfusion, we found that patients with >60% TBSA burn with inhalation injury have an 8% risk of developing sepsis in the low RBC group, which increases to 58% in the high RBC group (p<.05). Similar results were found for RBCs per operation, FFP, and FFP per operation (p<.05). There were no differences in age and gender between groups.

CONCLUSIONS

Pediatric burn suffering from a 60% TBSA burn with concomitant inhalation injury are more likely to develop sepsis if they are given high amounts of blood products, indicating an immunocompromised state following blood transfusion.

Liposomal gene transfer of keratinocyte growth factor improves wound healing by altering growth factor and collagen expression

BACKGROUND

Growth factors affect the complex cascade of wound healing; however, interaction between different growth factors during dermal and epidermal regeneration are still not entirely defined. In the present study, we thought to determine the interaction between keratinocyte growth factor (KGF) administered as liposomal cDNA with other dermal and epidermal growth factors and collagen synthesis in an acute wound.

MATERIALS AND METHODS

Rats received an acute wound and were divided into two groups to receive weekly subcutaneous injections of liposomes plus the Lac-Z gene (0.22 microg, vehicle), or liposomes plus the KGF cDNA (2.2 microg) and Lac-Z gene (0.22 microg). Histological and immunohistochemical techniques were used to determine growth factor, collagen expression, and dermal and epidermal structure.

RESULTS

KGF cDNA increased insulin-like growth factor-I (IGF-I), insulin-like growth factor binding protein-3 (IGFBP-3), and fibroblast growth factor (FGF), decreased transforming growth factor-beta (TGF-beta), while it had no effect on platelet-derived growth factor (PDGF) levels in the wound. KGF cDNA significantly increased collagen Type IV at both the wound edge as well as the wound bed, while it had no effect on collagen Type I and III. KGF cDNA increased re-epithelialization, improved dermal regeneration, and increased neovascularization.

CONCLUSIONS

Exogenous administered KGF cDNA causes increases in IGF-I, IGF-BP3, FGF, and collagen IV and decreases TGF-beta concentration. KGF gene transfer accelerates wound healing without causing an increase in collagen I or III.

Gut mucosal homeostasis and cellular mediators after severe thermal trauma and the effect of insulin-like growth factor-I in combination with insulin-like growth factor binding protein-3

Increased small bowel epithelial cell apoptosis and decreased cell proliferation lead to impairment of gut mucosal integrity and function after thermal injury. Impairment of gut integrity is associated with increased bacterial translocation and incidence of sepsis. The purpose of this study was to determine whether IGF-I/IGF binding protein (IGFBP)-3 can improve small bowel homeostasis after injury and by which cellular mechanisms these changes occur and to identify changes in apoptosis-related genes after burn and the effect of bile acid on small bowel epithelial cell apoptosis after burn. Rats sustained a thermal injury and received saline or the IGF-I/IGFBP-3 complex. Serum and small intestine were taken at 1, 2, 5, and 7 d after injury and serum inflammatory cytokines and mucosal apoptosis, proliferation, villous morphology, and apoptotic and proliferative mediators were measured. Apoptosis-related gene expression and the bile acid pool were determined in separate experiments up to 6 h after burn. Gut epithelial cell apoptosis as well as apoptosis-related genes were increased after the thermal injury, whereas bile acid secretion was significantly decreased (P < 0.05). IGF-I/IGFBP-3 significantly improved villous height and cells per villous by decreasing small bowel epithelial cell apoptosis and increasing proliferation (P < 0.05). Decreased apoptosis was associated with decreased Fas, Fas-ligand, and TNF when compared with saline (P < 0.05). A severe thermal injury caused an up-regulation of apoptosis and apoptosis-related genes and down-regulation of bile acid secretion. IGF-I/IGFBP-3 decreases small bowel epithelial cell apoptosis through down-regulation of the Fas pathway, which improves gut mucosal integrity after a severe thermal injury.