Biomedical subjects

M G Jeschke

Publications and source records attributed to M G Jeschke.

At least 37 records · Page 2Linked to original sources

PubMed2001

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.

3T3 Cells↗

PubMed2000

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.

Animals↗

PubMed2000

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.

Burns↗

PubMed2000

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.

Animals↗

PubMed2000

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.

Animals↗

PubMed2000

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.

Acute-Phase Reaction↗

PubMed2000

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.

Acute-Phase Reaction↗

PubMed2000

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.

Acute-Phase Proteins↗

PubMed2000

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.

Acidosis↗

PubMed2000

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.

Acute-Phase Proteins↗

PubMed2000

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.

Burns↗

PubMed2000

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.

Animals↗

PubMed1999

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.

Acute-Phase Proteins↗

PubMed1999

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.

Acute-Phase Reaction↗

PubMed1999

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.

Animals↗

PubMed1999

Growth hormone attenuates tumor necrosis factor alpha in burned children.

BACKGROUND: Recombinant human growth hormone (rhGH) has been shown to favorably modulate the acute-phase response and may improve the clinical outcome. OBJECTIVE: To examine whether rhGH attenuates the elevated tumor necrosis factor alpha (TNF-alpha) levels that correlate with increased multiorgan failure and mortality in burned adults and children. DESIGN: Twenty children with burns of greater than 40% of the total body surface area were randomly divided into 2 groups to receive placebo (n = 10) or rhGH, 0.2 mg/kg per day intramuscularly (n = 10). SETTING: Pediatric burn hospital. MAIN OUTCOME MEASURE: Serum TNF-alpha levels by enzyme-linked immunoassay at baseline (day 0) and at 21 and 42 days after injury. For statistical analysis, we used the Kruskal-Wallis and Friedman tests. RESULTS: No significant differences in age (mean +/- SD, 6.2+/-1.6 vs 5.0+/-1.2 years) or percentage of total body surface area burn (mean +/- SD, 65.1%+/-8.2% vs 57.1%+/-5.2%) could be shown between the groups given rhGH and placebo. Baseline TNF-alpha levels were elevated from reference values in both groups. Twenty-one and 42 days after rhGH administration, serum TNF-alpha levels were significantly decreased from those at baseline (P<.05). No significant decrease in TNF-alpha levels was observed in the placebo group (P = .5). CONCLUSIONS: Recombinant human growth hormone significantly lowers serum TNF-alpha levels after burn injury. This is consistent with the beneficial effect that rhGH has on the acute-phase response.

Burns↗

PubMed1999

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.

Animals↗

PubMed1999

Polyurethane vascular prostheses decreases neointimal formation compared with expanded polytetrafluoroethylene.

PURPOSE: Synthetic grafts have been increasingly used for complex vascular reconstructions in patients with limited autologous vein availability. Materials currently in use induce increased stenosis and graft thrombosis compared with autologous vein, especially in smaller vessels. We examined whether grafts constructed of a porous biodegradation-resistant polycarbonate polyurethane (PU) exert better biocompatibility in terms of faster endothelialization and decreased chronic proliferation of intimal cells compared with expanded polytetrafluoroethylene (ePTFE). METHODS: PU or ePTFE interposition grafts were implanted into the abdominal aortas of male Sprague-Dawley rats (PU, n = 37; ePTFE, n = 32). Grafts were removed at days 1, 7, 14, 28, and 56 and 6 months and were evaluated by immunohistochemical, electron microscopic, and morphometric techniques. Bromodeoxyuridine (BrdU) was injected at 1 and 24 hours before death to determine cellular proliferation. Endothelial cells and smooth muscle cells were identified with antibodies to von Willebrand factor and alpha-actin, respectively. RESULTS: The luminal surface of PU grafts took 4 weeks to completely endothelialize, whereas ePTFE grafts took 24 weeks (P <.05). Neointimal cell proliferation was lower in PU grafts compared with ePTFE at 56 days (1.4 +/- 0.1 versus 8.6 +/- 1.5, P <.001) and at 6 months (0.15 +/- 0.002 versus 3.4 +/- 0.5, p <.001). Neointimal thickness at 6 months after implantation was 3.2 +/- 0.8 micrometer for PU compared with 10.3 +/- 3.1 micrometer for ePTFE (P <.05). CONCLUSION: Polycarbonate polyurethane small vascular prostheses promoted faster luminal endothelialization, induced less chronic intimal proliferation, and produced a significantly thinner neointima than ePTFE grafts. These findings suggest that aliphatic-polycarbonate urethanes may offer advantages over standard materials such as ePTFE for vascular graft construction.

Animals↗