Fatty infiltration of the liver in severely burned pediatric patients: autopsy findings and clinical implications

BACKGROUND

Trauma induces hypermetabolic responses that are characterized by the mobilization of all available substrates. The marked increase of peripheral lipolysis after a burn can lead to the development of fatty liver, which has been associated with immunodepression and increased mortality.

METHODS

All autopsies of pediatric burn patients between January 1988 and January 1998 were reviewed. Patient demographics, hospital course, cause of death, and hepatic and septic macroscopic and microscopic findings were recorded.

RESULTS

Thirty-seven pediatric patients (4 +/- 1 years old) were included in the study. The mean burn size was 69% +/- 5% total body surface area burned. Eighty percent of the patients presented with fatty infiltration of the liver. Liver weight/body weight ratio was 77 +/- 5 gm/kg, representing 2.1 times the liver weight of age- and sex-matched controls (p < 0.001). Patients with severe fatty infiltration of the liver had a higher incidence of sepsis (p < 0.001).

CONCLUSION

Fatty infiltration of the liver is a common condition in fatal burns. Severe fatty infiltration of the liver is associated with an increased incidence of sepsis, although a causative effect could not be found. It is notable that fatty infiltration of the liver occurred in the complete absence of parenteral nutrition.

Possibilities of non-viral gene transfer to improve cutaneous wound healing

Enhancement of dermal and epidermal regeneration represents a crucial goal for the treatment of acute, e.g. burn and trauma wounds, and chronic wounds, e.g. diabetic, autoimmune, arterial and venous wounds. Studies defining molecular mechanisms of the complex cascade of wound healing have shown that growth factors represent a new therapeutic strategy. The clinical application of growth factors in the form of proteins has been shown to be of little benefit. Therefore new delivery systems and therapeutic strategies needed to be developed to improve dermal and epidermal regeneration, one of which is gene therapy. For successful gene delivery the selection of an appropriate vector has been shown to be paramount. Because Retroviruses, Adenoviruses and Adeno-Associated Viruses can cause immunologic reactions and mutations, non-viral delivery systems for gene therapy, such as liposomal gene transfer appear advantageous over viral gene therapy. This review discusses the success, potential and limitations of non-viral gene transfer to improve regeneration of dermal and epidermal structures.

The effect of short-term growth hormone treatment on growth and energy expenditure in burned children

Delays in growth are commonly observed in children who have sustained a severe cutaneous burn. The reasons for this growth delay are not completely known, but in adults, plasma growth hormone (GH) levels have been shown to decrease after thermal injury. If this is also the case in severely burned children, the low GH levels may contribute to their chronic growth delay. We propose that treatment with rhGH may prevent this burn-induced growth delay. Height velocities were measured for up to 2 years after injury in 38 burned children (age 7+/-1 years) with a 64+/-2% total burn surface area (TBSA) burn and a 59+/-3% third-degree burn who received 0.2 mg/kg/day rhGH during hospitalization. These height velocities were compared to 41 burned children (age 8+/-1 years) with a 64+/-3% TBSA burn and a 60+/-3% TBSA third-degree burn who were treated similarly but did not receive rhGH. Height velocities and height percentiles were compared to standard height velocity and percentile nomograms of unburned children. To determine the effect of rhGH on energy requirements, resting energy expenditures (REE) were measured by indirect calorimetry and compared to values calculated from the Harris-Benedict equation. All data are presented as mean+/-S.E.M. No differences in average height percentile could be shown between those receiving GH and controls at admission and 6 months after burn. There was, however, a significant difference (P<0.05) in height velocity during the first 2 years after burn between GH (47th+/-6 percentile) and controls (32nd+/-5 percentile). For rhGH-treated children, the REE was elevated by 34+/-4% versus 35+/-5% for controls. Recombinant human GH, given during acute hospitalization, maintained growth in severely burned children who would otherwise experience a significant growth delay. Treatment with rhGH did not atttenuate their elevated REE.

Effect of varying burn sizes and ambient temperature on the hypermetabolic rate in thermally injured rats

BACKGROUND

Small animals with scald covering 50% of their total body surface area (TBSA) have been used to study the hypermetabolic burn response. In the 50% TBSA burn rat model, the area of normal skin that is available for animal instrumentation is restricted and the mortality rate has been high. The purpose of this study was to determine whether a smaller burn size can induce a similar hypermetabolic response with mortality rates lower than those of the 50% TBSA model.

METHODS

Rats were randomly divided into four groups to receive a 0% (sham nonburned), 30%, 40%, or 50% TBSA third-degree scald burn. The hypermetabolic response was determined by measuring changes in body weight and oxygen consumption at ambient temperatures of 21, 26, and 31 degrees C for each burn size. Weight measurements were made daily while oxygen consumption was measured 7, 11, and 14 days after thermal injury.

RESULTS

All thermally injured rats lost body weight; however, there were no significant differences between the 30, 40, and 50% TBSA burn groups. Burn induced a hypermetabolic response as indicated by an increase in oxygen consumption from 130 to 200% that of sham nonburned rats. No significant difference in oxygen consumption could be shown over the study period between the three burn sizes at different ambient temperatures. Mortality was 0% in the sham and 30% group, 10% for the 40% group, and 50% for the 50% TBSA burn group.

CONCLUSIONS

From our study we conclude that a burn size covering 30% of the TBSA induces the same hypermetabolic response as a 50% TBSA burn.

Selective decontamination of the digestive tract in severely burned pediatric patients

Infection is still one of the leading causes of morbidity and mortality in severely burned patients. Evidence suggests that many of the responsible organisms are endogenous. Systemic antibiotic prophylaxis is not effective, and produces resistant strains of microorganisms. SDD has been postulated to be beneficial for controlling and decreasing infections in critically ill patients. Its efficacy in severely burned patients, however, remains controversial. In order to analyze the efficacy of selective decontamination of the digestive (SDD) tract, to decrease the bacterial colonization of the aerodigestive tract and burn wounds, and the incidence of septic complications in severely burned children, 23 pediatric patients affected of severe burns were prospectively randomized in a double-blinded study. Eleven patients received SDD (Polymyxin E, Tobramycin, and Amphotericin B), and 12 placebo. Demographics, hospital course, microbiology results, complications, infectious episodes, and serum levels of IL-1beta, IL-6, IL-10, and TNF-alpha were compared to determine the efficacy of SDD. Colonization rates to the wound, sputum, nasogastric aspirates, and feces were similar. Pneumonia, sepsis and other complications had similar incidence in both groups. Serum levels of all cytokines studied were also comparable, suggesting a similar inflammatory status in all patients, regardless of the treatment received. Patients in the SDD group, however, had a significantly higher incidence of diarrhea (P=0.003). We can conclude that selective decontamination of the digestive tract with Polymixin E, Tobramycin and Amphotericin B is not effective to decrease bacterial colonization and infectious episodes in severely burned pediatric patients.

Cell proliferation, apoptosis, NF-kappaB expression, enzyme, protein, and weight changes in livers of burned rats

Thermal injury has been shown to alter gut epithelium and heart myocyte homeostasis by inducing programmed cell death. The effect of thermal injury on hepatocyte apoptosis and proliferation, however, has not been established. The purpose of this study was to determine whether a large thermal injury increases liver cell apoptosis and proliferation and whether these changes were associated with alterations in hepatic nuclear factor kappaB (NF-kappaB) expression and changes in liver enzymes and amount of protein. Sprague-Dawley rats received a 40% total body surface area scald burn or sham burn. Rats were killed and livers were harvested at 1, 2, 5, and 7 days after burn. Liver cell apoptosis was determined by terminal deoxyuridine nick end labeling (TUNEL) assay and cell proliferation by immunohistochemistry for proliferating cell nuclear antigen. Hepatic NF-kappaB expression was determined by Western blot, and total hepatic protein content was determined by protein assay. Protein concentration decreased after burn compared with sham controls (P < 0.05). Liver cell apoptosis, proliferation, and NF-kappaB expression in hepatocytes increased in burned rats compared with controls (P < 0.05). It was concluded that thermal injury induces hepatic cell apoptosis and proliferation associated with an increase in hepatic NF-kappaB expression and a decrease in hepatic protein concentration.

Measurement of skin protein breakdown in a rat model

Whereas skin protein synthesis can be measured with different approaches, no method potentially applicable in humans is available for measurement of skin protein breakdown. To that end, we measured mixed skin fractional protein breakdown (FBR) in a rat model by use of a stable isotope method (tracee release method) originally developed to measure muscle protein breakdown. Skin mixed protein and collagen fractional synthesis rates (FSR) were also measured. A primed continuous infusion of L-[ring-(2)H(5)]phenylalanine and alpha-[5,5,5-(2)H(3)]ketoisocaproate (KIC) was given for 6 h. Arterial and skin phenylalanine and leucine free enrichments were measured at plateau (5-6 h) and during the decay that followed after the infusion was stopped. Skin FBR (%/h) was 0.260 +/- 0.011 with phenylalanine and 0.201 +/- 0.032 with KIC/leucine [P = not significant (NS)]. Mixed skin FSR (%/h) was 0.169 +/- 0.055 with phenylalanine and 0.146 +/- 0.020 with KIC/leucine (P = NS). Collagen FSR was 0.124 +/- 0.023%/h (P = NS vs. mixed protein FSR). The tracee release method is a sensitive method for measurement of skin protein breakdown; however, given the high intersubject variability of FSR, the calculation of skin net balance is not advisable.

Differential expression of hepatocyte growth factor in liver, kidney, lung, and spleen following burn in rats

Hepatocyte growth factor (HGF) plays a role as an organotropic factor for regeneration of injured organs. HGF is synthesized as an inactive single-chain precursor which is then converted to a biologically active heterodimeric form by proteolytic processing. Burn is the insult that results in hypovolemia which causes systemic organ injury. In this study, we investigated the induction and activation of HGF in various rat organs following burn trauma. Tissue HGF content determined as the total amount of the single-chain and heterodimeric form increased significantly in liver, lung, spleen, and kidney 12 h after burn. Molecular analysis revealed that HGF in these four organs of control rats was the single-chain precursor. In the burned rats, HGF was the single-chain form in the liver and lung, whereas heterodimeric HGF was detected in the spleen and kidney. Tissue protein content, an index of tissue injury, decreased significantly in the spleen and kidney, indicating that tissue damage was severe in these two organs. These results suggest that burn induces the production of HGF in various organs, and that the induced HGF is activated according to the severity of tissue damage caused by burn.

Early fluid resuscitation improves outcomes in severely burned children

BACKGROUND

Recent evidence suggests that timely fluid resuscitation can significantly reduce multiorgan failure and mortality in thermally injured children. In this study, children who received fluid resuscitation within 2 h of a thermal injury were compared with children in which fluid resuscitation was delayed by 2-12 h. We hypothesized that fluid resuscitation given within 2 h of a thermal injury attenuates renal failure, cardiac arrest, cardiac arrest deaths, incidence of sepsis, and overall mortality.

METHODS

A retrospective chart review was made on 133 children admitted to our institute from 1982 to 1999 with scald or flame burns covering more than 50% of their body surface area. Comparisons between early (< 2 h of injury) or delayed (> or = 2 h of injury) fluid resuscitation were made in children experiencing renal failure, sepsis, non-survivors with cardiac arrest requiring pulmonary and advanced life support, and overall mortality. Comparisons were made using the chi2-test with Yates' continuity correction and joint binomial confidence intervals using the Bonferroni correction.

RESULTS

The incidence of sepsis, renal failure, non-survivors with cardiac arrest, and overall mortality was significantly higher in burned children receiving fluid resuscitation that was delayed by 2 h or more compared with those receiving fluid resuscitation within 2 h of thermal injury (P < 0.001).

CONCLUSIONS

Data suggest that fluid resuscitation, given within 2 h of a thermal injury, may be one of the most important steps in the prevention of multi-organ failure and mortality.

Recombinant human growth hormone treatment in pediatric burn patients and its role during the hepatic acute phase response

OBJECTIVE

Recombinant human growth hormone (rHGH) has been shown to increase mortality in adult trauma patients; however, little has been reported on its side effects in children. The acute phase response has been suggested to be a contributing factor to trauma mortality. Therefore, the purpose of this study was to examine the effects of exogenous rHGH on the acute phase response in pediatric bum patients.

DESIGN

Prospective, randomized, double-blind study.

SETTING

Shriners Hospital for Children.

PATIENTS

Thermally injured pediatric patients, ranging in age from 0.1 to 16 yrs.

INTERVENTIONS

Twenty-eight thermally injured children received either 0.2 mg/kg/day of rHGH or saline (placebo) within 3 days of admission and for at least 25 days.

MEASUREMENTS AND MAIN RESULTS

Measurements were patient demographics, incidence of sepsis, inhalation injury, mortality, serum constitutive proteins, acute phase proteins, proinflammatory cytokines and insulin-like growth factor-I (IGF-I), insulin-like growth factor binding protein (IGFBP)-1, and IGFBP-3. No differences could be demonstrated in age, gender, burn size, incidence in sepsis (20% vs. 26%), inhalation injury (46% vs. 27%), or mortality (8% vs. 7%) between those receiving rHGH or placebo. Serum IGF-I and IGFBP-3 increased with rHGH treatment, whereas serum IGFBP-1 decreased compared with placebo (p < .05). Burned children treated with rHGH required significantly less albumin substitution to maintain normal levels compared with placebo (p < .05). Those receiving rHGH demonstrated a decrease in serum C-reactive protein and serum amyloid-A and an increase in serum retinol-binding protein compared with placebo (p < .05). rHGH decreased serum tumor necrosis factor-alpha and interleukin (IL)-1beta, whereas no changes were found for serum IL-1alpha, IL-6, and IL-10 compared with placebo (p < .05). Free fatty acids were elevated in burned children who received rHGH (p < .05).

CONCLUSION

Data indicate that rHGH does not increase mortality. rHGH decreased acute phase proteins, tumor necrosis factor-alpha, and IL-1beta, which is associated with increases in constitutive hepatic proteins and IGF-I.

Early release of third-degree eyelid burns prevents eye injury

Burns to the eyelids occur in more than 20 percent of flame injuries and can lead to ocular damage and even blindness. Burn wound contracture can cause ectropion of the eyelid, resulting in exposure keratitis, corneal ulcers, and conjunctivitis. At our hospital, early eyelid release and grafting has made a significant difference in the long-term outcomes of third-degree eyelid burns; however, the question of just how early eyelid release and grafting should take place is an unresolved issue. Fifty-seven children with third-degree eyelid burns were reviewed; 17 had eyelid release within 7 days of receiving eyelid burns and 40 had a delay in eyelid release of more than 7 days after injury. Analysis was by chi-square with the Yates continuity correction or Fisher's exact test when appropriate. Corneal ulcers developed in 2 of 17 of the early eyelid release of third-degree burns, compared with 25 of 40 delayed releases (p = 0.001), exposure keratitis in 3 of 17 early releases, and 30 of 40 in delayed release (p = 0.000); conjunctivitis was identified in 1 of 17 early releases and 14 of 40 delayed eyelid releases (p = 0.025). Release of eyelid burns within 7 days of injury can prevent the development of exposure keratitis, progressive conjunctivitis, corneal ulceration, and the need for corneal surgery. We suggest that early release and grafting should be the treatment of choice for children and young adults with third-degree burns to the eyelids.

Insulin-like growth factor I in combination with insulin-like growth factor binding protein 3 affects the hepatic acute phase response and hepatic morphology in thermally injured rats

OBJECTIVE

To modulate the hepatic acute phase response after a thermal injury by the administration of insulin-like growth factor I (IGF-I) in combination with its principal binding protein 3 (IGFBP-3).

SUMMARY BACKGROUND DATA

The hepatic acute phase response is a cascade of events initiated to restore homeostasis after trauma; however, a prolonged response contributes to multiorgan failure, hypermetabolism, complications, and death. Although IGF-1 has been shown to improve cell recovery and play a major role in liver regeneration, its effect on the hepatic acute phase response is not known.

METHODS

Sprague-Dawley rats (56 males) received a 60% total body surface area third-degree scald burn and were randomly divided to receive either rhIGF-I/BP-3 (10 mg/kg/day given subcutaneously) or saline (control). Rats were killed on postburn days 1, 2, 5, and 7 and serum glucose, electrolytes, acute phase reactant proteins, tumor necrosis factor alpha, interleukin 1 beta, interleukin 6, and rat and human serum IGF-I and IGFBP-3 were measured. Hepatic protein concentrations, hepatocyte proliferation, and hepatocyte apoptosis were determined.

RESULTS

No hypoglycemia or electrolyte imbalance could be shown in rats receiving the growth factor complex compared with saline. rhIGF-I/BP-3 increased serum protein on postburn days 2 and 7, albumin on days 5 and 7, and transferrin on days 1, 5, and 7, and decreased haptoglobin and alpha1-acid glycoprotein on postburn days 5 and 7 compared with controls. IGF-I/ BP-3 had no effect on type II acute phase proteins. Rats receiving IGF-I/BP-3 had lower serum levels of interleukin 1 beta and tumor necrosis factor alpha on the first day after burn compared with controls, whereas serum levels of interleukin 6 did not change. rhIGF-I/BP-3 significantly increased total liver protein content on postburn days 1, 2, 5, and 7 compared with controls. IGF-I/BP-3 increased hepatocyte proliferation and decreased hepatocyte apoptosis versus controls.

CONCLUSION

In combination with its principal binding protein, rhIGF-I decreases the proinflammatory cytokines interleukin 1 beta and tumor necrosis factor alpha, followed by a decrease in type I acute phase proteins. IGF-I/BP-3 had no effect on interleukin 6 and type II acute phase proteins. Decreases in acute phase protein and proinflammatory cytokine synthesis were associated with increases in constitutive hepatic proteins, total liver protein content, and hepatocyte proliferation. IGF-I/BP-3 attenuates the hypermetabolic response after thermal injury and may improve the clinical outcome.

Hepatocyte growth factor modulates the hepatic acute-phase response in thermally injured rats

OBJECTIVE

Hepatocyte growth factor (HGF) has been shown to modulate the acute-phase response in vitro. The specific in vivo role of HGF in this multifactorial response, however, remains unknown. This study examines the effects of exogenous HGF on the acute-phase response in thermally injured rats.

DESIGN

Prospective, randomized, laboratory study.

SETTINGS

Shriners Hospital for Children and University of Texas Medical Branch laboratories.

SUBJECTS

Fifty-six male Sprague-Dawley rats (weight range, 300-325 g).

INTERVENTION

Animals received a 60% total body surface area third-degree scald burn and were randomly divided to receive either 400 microg/kg/day i.v. HGF or saline (control).

MEASUREMENTS AND MAIN RESULTS

Serum acute-phase proteins, cytokines, and insulin-like growth factor (IGF)-I concentrations, as well as liver weight, protein and triglyceride content, IGF-I concentrations, and cytokine gene expression were measured 1, 2, 5, or 7 days after burn. Serum albumin was increased on days 2, 5, and 7 after burn, and transferrin was increased on day 7 after burn in HGF-treated rats compared with controls (p<.05). HGF increased alpha2-macroglobulin concentrations on postburn days 2, 5, and 7 compared with controls (p<.05). Serum interleukin-6 and tumor necrosis factor-alpha were significantly higher within 2 days of burn in rats treated with HGF (p<.05). HGF increased the hepatic gene expression of tumor necrosis factor-alpha compared with controls (p<.05). Serum IGF-I decreased in rats receiving HGF 1, 2, and 5 days after burn, whereas liver IGF-I concentrations were higher on days 1 and 7 after burn compared with controls (p<.05). Hepatic protein concentrations were higher in the HGF group compared with controls on postburn days 1, 2, and 7, with a concomitant increase in total liver weight (p<.05). HGF exerted a strong mitogenic effect on hepatocytes 1 and 2 days after thermal injury compared with controls (p<.05).

CONCLUSIONS

These findings suggest that HGF modulates the acute-phase response in vivo after burn and causes changes in liver morphology.

Burn and starvation increase programmed cell death in small bowel epithelial cells

Maintenance of gut mucosal homeostasis depends on a balance between cell proliferation and cell death. Gut mucosal integrity is impaired after severe burn and during starvation. We determined the effect of burn, starvation, and the combination of both on small bowel epithelial apoptosis and proliferation. Fifty adult male Fischer 344 rats (260-300 g) received a 60% full-thickness scald burn and were randomly divided into fed and starved groups. Small intestine was taken at 12, 24, and 48 hr after injury. All animals in the 12-hr group were starved while recovering from anesthesia. Apoptosis was quantified by immunohistochemical staining (TUNEL) and mucosal proliferation was determined by bromodeoxyuridine (BrdU) incorporation. The apoptotic index was higher in burned rats compared to controls at 12 hr after burn; both these groups were starved (P < 0.05). At 24 and 48 hr after burn, apoptosis was highest in the starved groups, with no additional effects of burn (P < 0.05). Mucosal epithelial cell proliferation was not different between groups at any time point. In conclusion, burn and starvation both increase apoptosis in the small bowel mucosa; however, these effects are not additive. Apoptosis could be attenuated by enteral feeding, which delineates the importance of early enteral feeding initiation after injury to maintain mucosal integrity.

Biodistribution and feasibility of non-viral IGF-I gene transfers in thermally injured skin

Gene therapy using cationic liposomes containing cDNA is a relatively new approach with great potential; however, little is known about the mechanisms of dermal gene transfer, its biodistribution, systemic transfection, and cellular uptake. This study identifies mechanisms, transfection rates, and biodistribution of liposomal gene transfers in the skin of thermally injured rats using cDNA gene constructs coding for insulin-like growth factor-I (IGF-I) and Lac Z. Male Sprague-Dawley rats (350 to 375 g) were given a 60% total body surface area full-thickness scald burn that was followed by weekly subcutaneous injections of normal saline (control, n = 10), liposomes plus 0.2 microg Lac Z cDNA construct driven by a cytomegalovirus (CMV) promoter (vehicle, n = 10), or liposomes containing 2.2 microg cDNA coding for IGF-I plus 0.2 microg Lac Z cDNA construct driven by a CMV promoter (IGF-I cDNA, n = 10). Gene transfection was determined by histochemical and luminescent beta-galactosidase assays of blood, skin, liver, spleen, and kidney. Transcription of IGF-I cDNA to IGF-I mRNA was determined in skin cells by Northern blot analyses. Levels of IGF-I protein in blood, skin, liver, spleen, and kidney were measured by radioimmunoassay. The biological activity of the translated IGF-I was evaluated by the mitogenic activity in dermal cells and the rate of re-epithelization. Gene transfection was observed only in skin cells. The expression of IGF-I mRNA increased in skin cells of burned rats receiving liposomes containing the IGF-I cDNA construct compared with liposomes without the construct or normal saline. IGF-I protein levels in the skin of rats receiving the IGF-I cDNA was 176 +/- 4 ng/ml compared with 105 +/- 6 ng/ml for liposomes alone or 90 +/-3 ng/ml for saline (p < 0.05). The translated IGF-I protein was found biologically active in the skin by increasing skin cell proliferation and accelerating re-epithelization 33 days after thermal injury (p < 0.05). No systemic transfection could be detected. Skin cells transfected with liposomes encapsulating the IGF-I cDNA constructs increased the expression of IGF-I mRNA transcript and the expression of a biologically active IGF-I protein. Liposomes containing the cDNA coding for IGF-I present an effective approach to gene therapy in the skin.

Long-term outcomes of burned children after in-hospital cardiac arrest

OBJECTIVE

Cardiopulmonary resuscitation (CPR) in severely burned patients experiencing cardiac arrest (CA) has been considered by some as futile. The objective of this article is to report predisposing factors and the outcomes of burned children experiencing in-hospital CA at our institution.

DESIGN

The records of 595 children admitted from 1985 to 1998 with burns covering >35% of their total body surface area were reviewed. Thirty-four children receiving CPR after in-hospital CA were studied for predisposing factors and long-term outcomes.

SETTING AND PATIENTS

Shriners Burns Hospital. Burned children of both genders, 0.5-19 yrs of age, who experienced in-hospital CA and received CPR.

INTERVENTION

Standard burn care and CPR.

MEASUREMENTS AND MAIN RESULTS

Predisposing factors of CA, mortality, and long-term outcomes were measured. The incidence of CA in burned children with burns on >35% total body surface area was 5.7%. No significant difference in age or burn size could be shown between long-term CA survivors (n = 17) and nonsurvivors (n = 17). CPR was successful (defined as survival for at least 1 day after CA) in 22 of 34 children (65%), with 17 of the 22 survivors (77%) experiencing long-term survival, currently from 2-14 yrs. Significant predisposing factors of CA were sepsis, identified in 53% of the nonsurvivors vs. 12% of the survivors (p<.05), and delayed fluid resuscitation (>2 hrs after burn injury), identified in 82% of the nonsurvivors vs. 6% of the survivors (p<.001). There was only one morbid long-term survivor. This survivor was diagnosed as having anoxic brain injury with persistent neurologic deficiencies.

CONCLUSION

In this study, 50% of the burned children experiencing CA are long-term survivors. We suggest that all burned children with CA should be afforded cardiopulmonary resuscitation.

Insulinlike growth factor I plus insulinlike growth factor binding protein 3 attenuates the proinflammatory acute phase response in severely burned children

OBJECTIVE

To determine the effect of insulinlike growth factor I (IGF-I) in combination with its principal binding protein (IGFBP-3) on the hepatic acute phase response in severely burned children.

SUMMARY BACKGROUND DATA

The hepatic acute phase response is a cascade of events initiated to restore homeostasis after trauma. A prolonged response, however, may contribute to multiple organ failure, hypermetabolism, complications, and death.

METHODS

Twenty-two children with a mean total body surface area (TBSA) burn of 57 +/- 3% were given a continuous infusion of 1 to 4 mg/kg/day IGF-I/BP-3 for 5 days after wound excision and grafting. Eight children with a TBSA burn of 54 +/- 4% were given saline as controls. Before and 5 days after excision and grafting, blood samples were taken for serum hepatic constitutive protein, acute phase protein, and proinflammatory cytokine analysis.

RESULTS

Serum IGF-I levels in burned children given the IGF-I/BP-3 complex increased from 113 +/- 15 to 458 +/- 40 ng/mL and IGFBP-3 levels increased from 1.8 +/- 0.2 to 3.1 +/- 0.3 ng/mL. Levels of serum constitutive hepatic proteins (prealbumin, retinol-binding protein, and transferrin) increased with IGF-I/BP-3, whereas levels of type I acute phase proteins (C-reactive protein, alpha1-acid glycoprotein, and complement C-3) decreased when compared with controls. The complex had no effect on type II acute phase proteins. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) levels decreased with IGF-I/BP-3 compared with controls, with no effect on interleukin-6.

CONCLUSION

Severely burned children receiving IGF-I/BP-3 showed a decrease in IL-1beta and TNF-alpha followed by a decrease in type I acute phase proteins that was associated with a concomitant increase in constitutive hepatic proteins. Attenuating the proinflammatory acute phase with IGF-1/BP-3 response may prevent multiple organ failure and improve clinical outcomes after thermal injury without any detectable adverse side effects.

Attenuation of the acute-phase response in thermally injured rats by cholesterol-containing cationic liposomes used as a delivery system for gene therapy

HYPOTHESIS

Cholesterol-containing cationic liposomes alone modulate the acute-phase response and cytokine expression in thermally injured rats and are an effective delivery system for gene therapy in trauma.

SETTING

Laboratory.

INTERVENTION

Fifty-six adult male Sprague-Dawley rats with a full-thickness scald burn covering 60% of total body surface area were randomly divided into 2 groups to receive either intravenous injections of cholesterol-containing cationic liposomes or saline (control).

MAIN OUTCOME MEASURES

Body weights, muscle and liver dry-wet weights, serum levels of constitutive hepatic proteins, acute-phase protein levels, and cytokine levels were determined at 1, 2, 5, and 7 days after thermal injury.

RESULTS

Rats receiving cholesterol-containing cationic liposomes had less body weight loss, increased serum transferrin levels, and decreased serum alpha1-acid glycoprotein levels when compared with controls (P<.05). Serum interleukin 1beta and tumor necrosis factor alpha levels were decreased in rats receiving liposomes at 1 and 2 days after burn compared with controls (P<.05).

CONCLUSIONS

These results suggest that cholesterol-containing cationic liposomes alone may have a beneficial effect in modulating the hypermetabolic response after burn injury by decreasing type 1 acute-phase proteins and the expression of the proinflammatory cytokines interleukin 1beta and tumor necrosis factor alpha. Therefore, cholesterol-containing cationic liposomes appear to be suitable as a delivery system for gene therapy in trauma.

Effect of multiple gene transfers of insulinlike growth factor I complementary DNA gene constructs in rats after thermal injury

HYPOTHESIS

Multiple subcutaneous injections of cholesterol-containing cationic liposomes encapsulating the complementary DNA (cDNA) gene for insulinlike growth factor I (IGF-I) increase the rate of transfected skin cells and result in increased IGF-I protein levels in the skin with subsequent improvement in wound healing when compared with a single injection.

SETTING

Laboratory.

INTERVENTION

Twenty-four adult male Sprague-Dawley rats (350-375 g) received a full-thickness scald burn on 60% of their body surface. These rats were randomly divided to receive either 1 injection of liposomes containing 2.2 microg-cytomegalovirus-driven cDNA coding for IGF-I and 0.2 microg of the Lac Z gene cDNA construct, or 2 injections of liposomes containing 2.2 microg cytomegalovirus-driven cDNA coding for IGF-I and 0.2 microg of the Lac Z gene cDNA construct.

MAIN OUTCOME MEASURES

Transfection rates and IGF-I protein levels in the skin and physiological responses to the IGF-I gene therapy, evaluated from changes in body weight, protein content in serum and liver, and the rate of burn wound healing.

RESULTS

There was a significant decrease in transfection rate and IGF-I protein expression distal from the injection site in animals receiving 1 injection, as compared with a consistent increase in rats receiving multiple injections. Multiple injections improved the response to thermal trauma by increasing the extent of the healed burn wound 33 days after thermal injury (single injection, 31% +/- 1% vs multiple injections, 38% +/- 2%), total serum protein (single injection, 52 +/- 0.5 g/L vs multiple injections, 55 +/- 0.6 g/L), and total liver protein (single injection, 82.0 +/- 0.3 mg/mL vs multiple injections, 91.0 +/- 3.8 mg/mL), P<.05.

CONCLUSIONS

Gene transfer rates can be increased by multiple injections of liposomes encapsulating IGF-I cDNA constructs. Increased transfer results in greater IGF-I protein skin concentrations, accelerated wound healing, and increased serum and liver protein concentrations. The clinical relevance of these findings is that liposomal gene constructs should be applied in well-defined distances to improve gene transfer in the skin, and thus clinical outcome after thermal injury.

The combination of growth hormone with hepatocyte growth factor alters the acute phase response

Recombinant human growth hormone (rhGH) and hepatocyte growth factor (HGF) have both been shown to individually modulate hepatic acute phase reactant proteins and cytokine expression following trauma through different pathways. Recombinant hGH has also been shown to decrease serum and hepatic HGF concentrations after a thermal injury. We hypothesized that the combination of rhGH plus HGF improves the burn-induced acute phase response. Fifty-six male Sprague-Dawley rats received a 60% TBSA third-degree scald burn and were randomly divided to receive either rhGH (2.5 mg/kg/day sc.) plus HGF (200 microg/kg i.v. every 12 h) or placebo (saline). Rats were sacrificed on post-burn days 1, 2, 5, or 7 and serum constitutive and acute phase proteins, TNF-alpha, IL-1beta, IL-6 and liver total protein measured. Hepatic cytokine gene expression, triglyceride concentration, and hepatocyte proliferation were also measured. In rats receiving rhGH/HGF, serum albumin increased on days 5 and 7 and transferrin on day 7 after burn compared to placebo (P<0.05). Haptoglobin decreased 5 days after burn compared to placebo (P<0.05). RhGH/HGF increased serum TNF-alpha on day 2 after burn, while it decreased serum IL-1beta on day 1 after burn compared with placebo (P<0.05). RhGH/HGF had no effect on hepatic cytokine gene expression compared with placebo. Liver total protein content and hepatocyte proliferation increased on days 1, 2, 5, and 7 after burn with rhGH/HGF treatment (P<0.05). These findings indicate that rhGH in combination with HGF exert additive effects on constitutive hepatic proteins and partial inhibitory effects on acute phase protein and cytokine expression. RhGH/HGF has a strong mitogenic effect on hepatocytes.

Effects of recombinant human growth hormone on the development of burn scarring

Anabolic agents, such as recombinant human growth hormone (rhGH), have been used effectively to ameliorate the catabolic response to burn injury and to improve wound-healing. However, in experimental animal models, growth hormone has also been associated with increased renal scarring. The effect of rhGH on the development of human scarring is unknown. Therefore, the purpose of this study was to assess the effect of rhGH on the scarring of human skin after burn injury. A series of 94 patients was studied in a prospective randomized double-blind clinical trial. Patients receiving 0.2 mg/kg/day subcutaneous rhGH during their acute hospital stays presented with the same quality and intensity of scarring as patients receiving a placebo. Similar reconstructive needs also resulted. The treatment of severely burned children with recombinant human growth hormone during the acute-phase hospital course did not increase scarring of the burn wound.

Increased expression of insulin-like growth factor-I in serum and liver after recombinant human growth hormone administration in thermally injured rats

BACKGROUND

Recombinant human growth hormone (rhGH) has been shown to modulate the hypermetabolic response and the hepatic acute-phase response after thermal injury. In vitro studies, however, demonstrated that rhGH activates insulin-like growth factor-I (IGF-I) gene transcription and production, suggesting that rhGH may exert some of its effects indirectly through IGF-I stimulation. The purpose of this study was to determine the effects of rhGH on serum and hepatic IGF-I in thermally injured rats.

METHODS

Sprague-Dawley rats (56 males) receiving a 60% TBSA third-degree scald burn were randomly divided to receive either rhGH (2.5 mg/kg/day im) or saline (control). Rats were sacrificed on postburn days 1, 2, 5, and 7 and serum IGF-I, hepatic IGF-I mRNA, and IGF-I protein concentration were measured. The physiologic response to changes in IGF-I levels was evaluated by measuring hepatocyte proliferation, total liver protein concentration, and muscle dry/wet weights.

RESULTS

Serum IGF-I was increased from postburn day 1 through day 7 in rats receiving rhGH compared to controls (P < 0.05). Hepatic IGF-I mRNA and IGF-I protein expression were increased from day 1 to 7 after burn in animals receiving rhGH when compared to controls (P < 0.05). Recombinant hGH increased hepatocyte proliferation at 5 days and total liver protein concentration at 5 and 7 days postburn compared to controls (P < 0.05). Muscle dry/wet weights increased in rats receiving rhGH at 7 days after burn compared to controls (P < 0.05).

SUMMARY

Liver and serum IGF-I levels decreased after a thermal injury. Recombinant hGH attenuated this decrease by stimulating hepatic IGF-I expression. Increases in IGF-I were associated with increases in hepatocyte proliferation and protein concentration in liver and muscle.

CONCLUSION

We suggest that rhGH modulates the hypermetabolic response through IGF-I stimulation in the hepatic parenchyma.

IGF-I gene transfer in thermally injured rats

Exogenous insulin-like growth factor-I (IGF-I) is known to improve the pathophysiology of a thermal injury, however, deleterious side-effects have limited its utility. Cholesterol-containing cationic liposomes that encapsulate complementary DNA (cDNA) are nonviral carriers used for in vivo gene transfection. We propose that liposome IGF-I gene transfer will accelerate wound healing in burned rats and attenuate deleterious side-effects associated with high levels of IGF-I. To test this hypothesis IGF-I gene constructs, encapsulated in liposomes, were studied for their efficacy in modulating the thermal injury response. Thirty adult male Sprague-Dawley rats were given a 60% TBSA scald burn and randomly divided into three groups to receive weekly subcutaneous injections of liposomes plus the lacZ gene coding for beta-galactosidase, liposomes plus cDNA for IGF-I and beta-galactosidase or liposomes plus the rhIGF-I protein. Body weights and wound healing were measured. Muscle and liver dry/wet weights and IGF-I concentrations in serum, skin and liver were measured by radioimmunoassay. Transfection was confirmed by histochemical staining for beta-galactosidase. Rats receiving the IGF-I cDNA constructs exhibited the most rapid wound re-epithelialization and greatest increase in body weight and gastrocnemius muscle protein content (P < 0.05). Local IGF-I protein concentrations in the skin were higher when compared to liposomes containing only the lacZ gene (P < 0.05) Transfection was apparent in the cytoplasm of myofibroblasts, endothelial cells and macrophages of the granulation tissue. Liposomes containing the IGF-I gene constructs proved effective in preventing muscle protein wasting and preserving total body weight after a severe thermal injury.

Recombinant human growth hormone alters acute phase reactant proteins, cytokine expression, and liver morphology in burned rats

BACKGROUND

The effects of exogenous recombinant human growth hormone (rhGH) on hepatic acute phase reactant proteins, cytokine expression, and liver morphology were studied in thermally injured rats to define whether rhGH alters the acute phase response.

MATERIALS AND METHODS

Sprague-Dawley rats (56 males) receiving a 60% TBSA third-degree scald burn were randomly divided into two groups to receive either 2.5 mg/kg/day sc rhGH or saline. Rats were sacrificed on Postburn Days 1, 2, 5, and 7. Serum acute phase reactant proteins and cytokines TNF-alpha, IL-1alpha, IL-1beta, and IL-6 were measured. Hepatocyte proliferation, hepatic cytokine gene expression, and liver protein concentrations were determined.

RESULTS

Recombinant hGH increased serum albumin on Days 5 and 7 after burn (P < 0.05). Serum haptoglobin and alpha1-acid glycoprotein levels decreased at 2, 5, and 7 days after burn compared to saline (P < 0.05). In rats treated with rhGH, serum IL-1beta decreased 1 day postburn, while serum TNF-alpha increased 5 days after burn compared to saline (P < 0.05). Serum IL-6 and IL-1alpha did not change. Hepatic RNA levels for TNF-alpha were significantly elevated on Day 1 postburn compared to saline (P < 0. 05). Hepatic protein content increased on Days 2, 5, and 7 postburn compared to saline (P < 0.05). Hepatocyte proliferation in rhGH-treated rats increased on Day 5 after burn (P < 0.05).

CONCLUSION

Data indicate that rhGH alters the hepatic acute phase response by decreasing type I acute phase proteins and modulating IL-1-like cytokine expression. These changes are associated with increased hepatocyte mitosis and serum and total liver protein concentrations.