The metabolic effects of thermal injury

Metabolic response to burn injury: a comprehensive bibliometric study

Objective

Burns lead to systemic changes manifested by systemic disturbances in water-electrolyte balance and systemic metabolic and inflammatory responses. The hypermetabolic response after a burn injury relies on metabolic, hormonal, and inflammatory dysregulation mechanisms. This study aimed to provide a comprehensive bibliometric analysis of the burn metabolism research field, identifying key trends, influential contributors, and emerging research hotspots to inform future investigative efforts. Ultimately, we conducted an extensive review of the literature, synthesizing the findings to clarify the present understanding within our field of study.

Methods

We obtained 8,823 scientific publications on burn injury and metabolism from the core Web of Science (WOS) database collection. In this work, biblioshiny was used to visualize and analyze the data, and VOSviewer was used to verify the results.

Results

From a total of 8,823 publications, we found a general upward trend in annual publications and citation frequency. According to Bradford's Law, 21 high-production journals were classified as core sources based on the number of publications, and the most productive journal was Burns. The most published countries and authors in this field were the United States and Herndon DN. The most local cited document in this field was the article titled "Catecholamines: Mediator of the Hypermetabolic Response to Thermal Injury" authored by Wilmore DW. The thematic map showed that studies on injury, thermal injury, and sepsis were relatively mature. In contrast, research on metabolism, stress, and responses, and research on mortality, resistance, and management were less well-developed but were essential for the field.

Conclusion

Research on burns and metabolism is increasing. Based on the bibliometric analysis, our study summarized the complex interplay between burn-induced systemic metabolic alterations and inflammatory responses, emphasizing the significance of hypermetabolism and its management. The role of propranolol, insulin, oxandrolone, and nutritional interventions in modulating the hypermetabolic state was discussed. Additionally, our study underscored the challenges of managing sepsis and drug-resistant infections in burn patients as an important future area of research.

Long-term sequelae of critical illness in sepsis, trauma and burns: A systematic review and meta-analysis

BACKGROUND

Sepsis, major trauma, and severe burn injury are life-threatening critical illnesses that remain significant contributors to worldwide morbidity and mortality. The three underlying etiologies share pathophysiological similarities: hyperinflammation, hypermetabolism, and acute immunomodulation. The aims of this study were to assess the current state of long-term outcome research and to identify key outcome parameters between the three forms of critical illness.

METHODS

This systematic review and meta-analysis (MA) were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. PubMed was searched from January 1, 1975, to December 31, 2019. Studies were assessed for eligibility by independent reviewers. Inclusion criteria were studies reporting at least a 6-month follow-up of health-related quality of life and organ-specific sequelae within the three etiologies: severe burn injury, sepsis, and major trauma.

RESULTS

In total, 125 articles could be included in the systematic review and 74 in the MA. The mean follow-up time was significantly longer in burn studies, compared with sepsis and trauma studies. The majority of patients were from the sepsis group, followed by burns, and major trauma studies. In the overall health-related quality of life, as assessed by Short Form 36 and European Quality-of-Life Index, the three different etiologies were comparable with one another.

CONCLUSION

The effects of critical illness on survivors persist for years after hospitalization. Well-reported and reliable data on the long-term outcomes are imperative, as they can be used to determine the treatment choice of physicians and to guide the expectations of patients, improving the overall quality of care of three significant patient cohorts.

LEVEL OF EVIDENCE

Systematic review and MA, level III.

Advanced age heightens hepatic damage in a murine model of scald burn injury

BACKGROUND

Elderly burn patients exhibit a lower survival rate compared with younger counterparts. The liver is susceptible to damage after burn injury, which predisposes to poor outcomes. Lipid homeostasis and the antioxidant glutathione system play fundamental roles in preserving liver integrity. Herein, we explored changes in these major pathways associated with liver damage in the aging animals after burn injury.

METHODS

We compared liver enzymes, histology, lipid-peroxidation, and glutathione-metabolism profiles from young and aged female mice after a 15% total body surface area burn. Mice were euthanized at 24 hours after injury, and livers and serum were collected.

RESULTS

Aged burn animals exhibited elevated (p < 0.05) aspartate aminotransferase and alanine aminotransferase levels and increased inflammatory cell infiltration, edema, and necrosis compared with their younger counterparts. The percentage of adipophilin-stained area in livers from young sham, young burn, aged sham, and aged burn groups was 10%, 44%, 16%, and 78% (p < 0.05), respectively. Liver malondialdehyde levels were 1.4 ± 0.5 nmol/mg, 2.06 ± 0.2 nmol/mg, 1.81 ± 0.12 nmol/mg, and 3.45 ± 0.2 nmol/mg (p < 0.05) in young sham, young burn, aged sham, and aged burn mice, respectively. Oxidized glutathione (GSSG) content increased 50% in the young burn, and 88% in aged burn animals compared with the young sham group (p < 0.05). The reduced glutathione GSH/GSSG ratio was significantly reduced by 54% in aged burn mice compared with young sham animals (p < 0.05). Furthermore, glutathione peroxidase gene expression showed a 96% decrease in the aged burn group compared with young sham mice (p < 0.05).

CONCLUSION

Aged burn animals exhibit severe liver damage from heightened lipid peroxidation and inadequate antioxidative response. The increased peroxidation is associated with abundant lipid deposits in hepatic tissue postburn and a weak antioxidative response due to hepatic glutathione peroxidase downregulation. Further studies will focus on the functional significance of these findings concerning hepatic homeostasis.

Preparation and characterization of selenium-rich polysaccharide from Phellinus igniarius and its effects on wound healing

The modified of polysaccharides show various bio-activities. In our work, Phellinus igniarius Selenium-enriched mycelias polysaccharides (PSeP) were prepared from Phellinus igniarius, and its antioxidant and anti-inflammatory effects on injured mice were evaluated. The selenium content and physical properties of polysaccharides were characterized by GC, HPGPC, and FT-IR analysis. The results showed that PSeP could reduce reactive oxygen species (ROS) levels, myeloperoxidase (MPO) activity as well as malondialdehyde (MDA) content. Meanwhile, it increased the enzyme activities of glutathione peroxidase (GSH-Px) and catalase (CAT). Finally, it showed obvious wound healing effects in vivo. Moreover, PSeP could clear the ROS without obvious cytotoxicity. PSeP could further improve its ability to clear ROS level to promote skin wound healing in mice three days in advance.

Alcohol Intoxication and the Postburn Gastrointestinal Hormonal Response

Gastrointestinal hormones are essential in postburn metabolism. Since near 50% of burn victims test positive for blood alcohol levels at hospital admission and have inferior outcomes compared to nonintoxicated burn patients; we hypothesized that the gastrointestinal hormone secretion is compromised in intoxicated burn victims. To test our theory, we quantified gastrointestinal hormones serum levels in a combine ethanol intoxication and burn injury mouse model. Thus, mice received a daily dose of ethanol for 3 days, rested 4 days, and were given ethanol 3 additional days. Mice underwent 15% TBSA scald burn 30 minutes after their last ethanol dose. Serum samples were collected 24 hours after burn injury. Nonintoxicated burned mice exhibited an increase in glucose, insulin, ghrelin, plasminogen activator inhibitor-1, leptin, and resistin by 1.4-, 3-, 13.5-, 6.2-, 9.4-, and 2.4-fold, respectively, compared to sham vehicle mice (P < .05). Burn injury also reduced serum gastric inhibitory polypeptide (GIP) by 32% compared to sham-injured, vehicle-treated mice. Leptin, resistin, glucagon-like peptide-1, as well as insulin, were not different from sham groups when intoxication preceded burn injury. Nevertheless, in burned mice treated with ethanol, gastric inhibitory polypeptide and glucagon serum levels exhibited a significant fold increase of 3.5 and 4.7, respectively. With these results, we conclude that 24 hours after burn injury, mice developed significant changes in gastrointestinal hormones, along with hyperglycemia. Moreover, the combined insult of burn and ethanol intoxication led to additional hormonal changes that may be attributed to a potential pancreatic dysfunction. Further multiday studies are required to investigate the etiology, behavior, and clinical significance of these hormonal changes.

Nutritional Support of the Critically Ill Small Animal Patient

Over the past couple of decades, a component of veterinary critical care was simply to ensure that nutritional support formed some part of the treatment plan. Great emphasis was made on early placement of feeding tubes in critically ill veterinary patients to facilitate enteral feeding. Progress has been made on techniques for nutritional provision, establishing feasibility of nutritional interventions in various patient populations and establishing that nutritional support does have an important role in veterinary critical care. Some refinement of appropriate caloric targets in critically ill animals has decreased complications relating to overfeeding, but further work is required to establish optimal feeding regimes.

Burns in the Elderly: Potential Role of Stem Cells

Burns in the elderly continue to be a challenge despite advances in burn wound care management. Elderly burn patients continue to have poor outcomes compared to the younger population. This is secondary to changes in the quality of the aged skin, leading to impaired wound healing, aggravated immunologic and inflammatory responses, and age-related comorbidities. Considering the fast-growing elderly population, it is imperative to understand the anatomic, physiologic, and molecular changes of the aging skin and the mechanisms involved in their wound healing process to prevent complications associated with burn wounds. Various studies have shown that stem cell-based therapies improve the rate and quality of wound healing and skin regeneration; however, the focus is on the younger population. In this paper, we start with an anatomical, physiological and molecular dissection of the elderly skin to understand why wound healing is delayed. We then review the potential use of stem cells in elderly burn wounds, as well as the mechanisms by which mesenchymal stem cell (MSCs)-based therapies may impact burn wound healing in the elderly. MSCs improve burn wound healing by stimulating and augmenting growth factor secretion and cell proliferation, and by modulating the impaired elderly immune response. MSCs can be used to expedite healing in superficial partial thickness burns and donor site wounds, improve graft take and prevent graft breakdown.

Lactate and lactate clearance in critically burned patients: usefulness and limitations as a resuscitation guide and as a prognostic factor

OBJECTIVE

Lactate levels to guide resuscitation in critically burned patients are controversial. The purpose of our study was to determine whether absolute lactate values or lower lactate clearance predict mortality, and whether these are useful tools in the resuscitation phase.

METHODS

We conducted a prospective, unicentric, observational study of a cohort of 214 burn patients admitted in the Burn Intensive Care Unit. We collected demographic and laboratory data, complications, absolute lactate levels and lactate clearance every 8 h since admission to 72 h. In critical patients we monitored hemodynamic parameters with transpulmonary thermodilution. We used Student's t-test or nonparametric tests, mixed models and Pearson and Spearman methods, Fisher's exact and chi-squared test.

RESULTS

Of the 214 patients, 76.6% were male, mean age were 46 ± 15 years and 23.0 ± 19.5% of Total Basal Surface Area (TBSA) burned. Initial mean absolute levels of lactate were 2.02 ± 1.62 mmol/L in survivors vs. 4.05 ± 3.90 mmol/L in nonsurvivors. Initial elevated lactate levels increased mortality (p < .001), length of ICU stay, mechanical ventilation and shock. In the subgroup of burned TBSA < 20%, lowering the lactate cut-off point from 2.0 to 1.8 mmol/L improved the mortality prediction (OR:9.3). We found no relationship between lactate clearance in the first 24 h and mortality. In more severe patients (> 20% TBSA burned and initial lactate levels > 2), a good correlation was found between lactate and cardiac index; but not with intrathoracic blood volume index (ITBVI). Patients with low ITBVI preload (< 600 mL/m²) did not show significant differences in lactate clearance compared with those with ITBVI > 600.

CONCLUSIONS

Initial elevated lactate levels are a factor of poor prognosis and the cut-off point that best predicts mortality should be adjusted in the patients with TBSA burned < 20%. The global clearance of lactate in the first 24 h, unlike what occurs in other injuries, does not correlate with mortality. Monitoring lactate can ensure adequate peripheral perfusion during resuscitation with lower than normal fluid preload values.

Burns: modified metabolism and the nuances of nutrition therapy

OBJECTIVE

To review the effects of burn injury on nutritional requirements and how this can best be supported in a healthcare setting.

METHOD

A literature search for articles discussing nutrition and/or metabolism following burn injury was carried out. PubMed, Embase and Web of Science databases were searched using the key search terms 'nutrition' OR 'metabolism' AND 'burn injury' OR 'burns'. There was no limitation on the year of publication.

RESULTS

A total of nine articles met the inclusion criteria, the contents of which are discussed in this manuscript.

CONCLUSION

Thermal injury elicits the greatest metabolic response, among all traumatic events, in critically ill patients. In order to ensure burn patients can meet the demands of their increased metabolic rate and energy expenditure, adequate nutritional support is essential. Burn injury results in a unique pathophysiology, involving alterations in endocrine, inflammatory, metabolic and immune pathways and nutritional support needed during the inpatient stay varies depending on burn severity and idiosyncratic patient physiologic parameters.

Effect of Intravenous Fluid Volumes on the Adrenal Glucocorticoid Response After Burn Injury in Swine

Severe thermal injury induces metabolic and physiological stress, prompting a disruption in the hypothalamic-pituitary-adrenal axis. The objective of this study was to evaluate potential confounding effects of Lactated Ringer's (LR) resuscitation on adrenal damage and cortisol production following burn. Anesthetized swine were instrumented with jugular catheters and sustained 40% TBSA burns from brass probes heated to 100°C. Animals recovered to consciousness and received IV fluid resuscitation with LR at two different volumes: 15 ml/kg/d (limited volume [LV], n = 6) or 2 ml/kg/%TBSA/d (modified Brooke [MB], n = 6). Nonburned animals (Sham) were both oral and IV fluid restricted (S-FR, n = 4) to induce stress. Computed tomography (CT) angiographies were performed at baseline (BL) and 48 hours postburn, while blood and urine samples were collected at BL, 6, 24, and 48 hours postburn, with euthanasia at 48 hours for adrenal harvesting. Urinary cortisol was elevated following burn/surgery in all animals and returned back to BL in S-FR (404 ± 48 pg/mg creatinine) but not MB (1332 ± 176 pg/mg creatinine; P = .005) or LV (1223 ± 335 pg/mg creatinine; P = .07) by 48 hours. Gene expression of cleavage enzymes (3β-HSD, CYP17, CYP11, and CYP21) along the cortisol synthesis pathway showed minimal changes. Adrenal apoptosis (Terminal deoxynucleotidyl transferase dUTP nick-end labeling [TUNEL] staining) was greatest in the MB group (P ≤ .01) when compared to S-FR, partly due to elevations in c-Jun N-terminal kinase. Adrenal hemorrhaging was also greatest in MB animals, with no differences in tissue volume or wet-to-dry ratio. However, tissue levels of cytokines IL-1β, IL-10, and IL-12 were greatest in LV. Burn injury elevates urinary cortisol and compromises adrenal gland integrity, which is affected by IV fluid volume.

Pediatric enteral nutrition therapy for burn victims: when should it be initiated?

Objective

To review the scientific evidence regarding the initiation of enteral nutrition in the pediatric burn population.

Methods

This study was a systematic review and meta-analysis of randomized clinical trials comparing early enteral nutrition and late enteral nutrition in individuals aged 1 month to 18 years with burns. The MEDLINE/PubMed, Embase and Cochrane Library databases were searched using the terms "burns", "fires", "child nutrition disorders", "nutritional support" and related terms.

Results

Three articles that included a total of 781 patients were identified. There was no significant difference in the mortality rate between the early and late groups (OR = 0.72, 95%CI = 0.46 - 1.15, p = 0.17). Patients who received early enteral nutrition had a 3.69-day reduction in the length of hospital stay (mean difference = -3.69, 95%CI = -4.11 - -3.27, p < 0.00001). There was a higher incidence of diarrhea and vomiting and decreased intestinal permeability in the early group. This group also presented higher a serum insulin concentration and insulin/glucagon ratio as well as lower caloric deficit and weight loss when compared to the control group.

Conclusion

Analysis of the different intragroup variables suggests the importance of starting nutritional support early. Considering the number of pediatric burn patients, there is a need for robust studies with greater scientific impact.

Contributors to the length-of-stay trajectory in burn-injured patients

OBJECTIVES

Burn patients have a highly variable length-of-stay (LOS) due to the complexity of the injury itself. The LOS for burn patients is estimated as one day per percent total body surface area (TBSA) burn. To focus care expectation and prognosis we aimed to identify key factors that contribute to prolonged LOS.

METHODS

This was a retrospective cohort-study (2006-2016) in an adult burn-centre that included patients with ≥10% TBSA burn. Patients were stratified into expected-LOS (<2 days LOS/%TBSA) and longer-than-expected-LOS (≥2 days LOS/%TBSA). We assessed demographics, comorbidities, and in-hospital complications. Logistic regression and propensity matching was utilized.

RESULTS

Of the 583 total patients, 477 had an expected-LOS whereas 106 a longer-than-expected-LOS. Non-modifiable factors such as age, 3rd degree TBSA%, inhalation injuries and comorbidities were greater in the exceeded LOS patients. Subsequent matched analysis revealed factors like number of procedures performed, days ventilated and in-hospital complications (bacteremia, pneumonia, sepsis, graft loss, and respiratory failure) were significantly increased in the longer-than-expected-LOS group.

CONCLUSIONS

Progress has been made to update the conventional one day/%TBSA to better aid health care providers in giving appropriate outcomes for patients and their families and to supply intensive care units with valuable data to assess quality of care and to improve patient prognosis.

Contemporary Burn Survival

BACKGROUND

The standard of burn treatment today reflects major advances. We sought to quantitate the impact of these advances on burn survival via age-stratified mortality ratios compared with other reported mortality analyses in burns.

STUDY DESIGN

Age, percent of the total body surface area (TBSA) burned, presence of inhalation injury, length of stay, and survival status were recorded at admission and at discharge for all new burn admissions between 1989 and 2017. The expected mortality probability was calculated using historical multiple regression techniques and compared with observed data. We developed a prediction model for our observed data.

RESULTS

Between 1989 and 2017, there were 10,384 consecutive new burn admissions, with 355 mortalities (median age, 13 years; median percent TBSA burn, 11%). We saw a significant decrease in our observed mortality data compared to historical predictions (p < 0.0001), and a 2% reduction per year in mortality during the 3 decades. The prediction model of mortality for the data is as follows: Pr(dying) = ex/(1 + ex) where x = -6.44 - 0.12 age + 0.0042 age2 - 0.0000283 age3 + 0.0499 TBSA + 1.21 Inhalation Injury + 0.015 third degree TBSA.

CONCLUSIONS

The reduction in mortality over time may be attributed to successful changes in standard of care protocols in the burn center that improved the outlook for burned individuals, including protocols for management of inhalation injury, nutrition, resuscitation, and early excision and grafting.

Proteasome Inhibition After Burn Injury

The objective of this study was to assess the effects of proteasome inhibition on the development of burn-induced hypermetabolism. Rats underwent 30-40% total BSA scald burn or sham injury. The proteasome inhibitor bortezomib (0.1 mg/kg) or vehicle (n = 10) was administered i.p. 3× weekly starting at 2 hours (early bortezomib, n = 20) or 48 hours (late-bortezomib, n = 13) postburn. Body weights were determined weekly. Resting energy expenditures (REE) were measured at days 0 (baseline), 7, 14, 21, and 42 postburn. At day 42, blood and pectoral muscle were harvested. Routine blood chemistry parameters were analyzed. Proteasome content, proteasome peptidase activities, and ubiquitin-protein conjugates were measured in muscle extracts. As compared with sham-vehicle-treated animals, specific proteasome activities were increased after burn and vehicle treatment. Bortezomib treatment inhibited proteasome activities and increased ubiquitin-protein conjugates after sham and burn injury. Bortezomib treatment did not affect REE after sham procedure. REE significantly increased by 47% within 7 days and remained elevated until day 42 after burn and vehicle treatment. After early-bortezomib treatment, burn-induced increases in REE were delayed and significantly reduced by 42% at day 42, as compared with vehicle treatment. With late-bortezomib treatment, burn-induced increases in REE were also delayed but not attenuated at day 42. Mortality was 20% with vehicle, 65% (median survival time: 1.875 days) with early-bortezomib and 25% with late-bortezomib treatment after burns (P < .05 early-bortezomib vs vehicle and late-bortezomib). Proteasome inhibition delays development of burn-induced hypermetabolism. Although proteasome inhibition early after burn injury reduces the hypermetabolic response, it significantly increases early burn-associated mortality.

Metformin-associated lactic acidosis (MALA): Moving towards a new paradigm

Although metformin has been used for over 60 years, the balance between the drug's beneficial and adverse effects is still subject to debate. Following an analysis of how cases of so-called "metformin-associated lactic acidosis" (MALA) are reported in the literature, the present article reviews the pitfalls to be avoided when assessing the purported association between metformin and lactic acidosis. By starting from pathophysiological considerations, we propose a new paradigm for lactic acidosis in metformin-treated patients. Metformin therapy does not necessarily induce metformin accumulation, just as metformin accumulation does not necessarily induce hyperlactatemia, and hyperlactatemia does not necessarily induce lactic acidosis. In contrast to the conventional view, MALA probably accounts for a smaller proportion of cases than either metformin-unrelated lactic acidosis or metformin-induced lactic acidosis. Lastly, this review highlights the need for substantial improvements in the reporting of cases of lactic acidosis in metformin-treated patients. Accordingly, we propose a check-list as a guide to clinical practice.

The influence of sex steroid hormones on the response to trauma and burn injury

Trauma and related sequelae result in disturbance of homeostatic mechanisms frequently leading to cellular dysfunction and ultimately organ and system failure. Regardless of the type and severity of injury, gender dimorphism in outcomes following trauma have been reported, with females having lower mortality than males, suggesting that sex steroid hormones (SSH) play an important role in the response of body systems to trauma. In addition, several clinical and experimental studies have demonstrated the effects of SSH on the clinical course and outcomes following injury. Animal studies have reported the ability of SSH to modulate immune, inflammatory, metabolic and organ responses following traumatic injury. This indicates that homeostatic mechanisms, via direct and indirect pathways, can be maintained by SSH at local and systemic levels and hence result in more favourable prognosis. Here, we discuss the role and mechanisms by which SSH modulates the response of the body to injury by maintaining various processes and organ functions. Such properties of sex hormones represent potential novel therapeutic strategies and further our understanding of current therapies used following injury such as oxandrolone in burn-injured patients.

The clinical significance of the MIF homolog d-dopachrome tautomerase (MIF-2) and its circulating receptor (sCD74) in burn

BACKGROUND

We reported earlier that the cytokine macrophage migration inhibitory factor (MIF) is a potential biomarker in burn injury. In the present study, we investigated the clinical significance of the newly discovered MIF family member d-dopachrome tautomerase (DDT or MIF-2) and their common soluble receptor CD74 (sCD74) in severely burned patients.

METHODS

DDT and sCD74 serum levels were measured 20 severely burned patients and 20 controls. Serum levels were correlated to the abbreviated burn severity index (ABSI) and total body surface area (TBSA) followed by receiver operating characteristic (ROC) analysis. Data were supported by gene expression dataset analysis of 31 burn patients and 28 healthy controls.

RESULTS

CD74 and DDT were increased in burn patients. Furthermore, CD74 and DDT also were elevated in septic non-survivors when compared to survivors. Serum levels of DDT showed a positive correlation with the ABSI and TBSA in the early stage after burn, and the predictive character of DDT was strongest at 24h. Serum levels of CD74 only correlated with the ABSI 5 days after injury.

CONCLUSIONS

DDT may assist in the monitoring of clinical outcome and prediction of sepsis during the early post-burn period. Soluble CD74 and MIF, by contrast, have limited value as an early predictor of death due to their delayed response to burn.

Effects of a caspase and a calpain inhibitor on resting energy expenditures in normal and hypermetabolic rats: a pilot study

Several diseases induce hypermetabolism, which is characterized by increases in resting energy expenditures (REE) and whole body protein loss. Exaggerated protein degradation is thought to be the driving force underlying this response. The effects of caspase and calpain inhibitors on REE in physiological and hypermetabolic conditions, however, are unknown. Thus, we studied whether MDL28170 (calpain inhibitor) or z-VAD-fmk (caspase inhibitor) affect REE under physiological conditions and during hypermetabolism post-burn. Rats were treated five times weekly and observed for 6 weeks. Treatment was started 2 h (early) or 48 h (late) after burn. In normal rats, MDL28170 transiently increased REE to 130 % of normal during week 2-4. z-VAD-fmk reduced REE by 20-25 % throughout the observation period. Within 14 days after burns, REE increased to 130+/-5 %. Whereas MDL28170/early treatment did not affect REE, MDL28170/late transiently increased REE to 180+/-10 % of normal by week 4 post-burn. In contrast, with z-VAD-fmk/early REE remained between 90-110 % of normal post-burn. z-VAD-fmk/late did not affect burn-induced increases in REE. These data suggest that caspase cascades contribute to the development of hypermetabolism and that burn-induced hypermetabolism can be pharmacologically modulated. Our data point towards caspase cascades as possible therapeutic targets to attenuate hypermetabolism after burns, and possibly in other catabolic disease processes.

Metabolomics to identify biomarkers and as a predictive tool in inflammatory diseases

There is an overwhelming need for a simple, reliable tool that aids clinicians in diagnosing, assessing disease activity and treating rheumatic conditions. Identification of biomarkers in partially understood inflammatory disorders has long been sought after as the Holy Grail of Rheumatology. Given the complex nature of inflammatory conditions, it has been difficult to earmark the potential biomarkers. Metabolomics, however, is promising in providing new insights into inflammatory conditions and also identifying such biomarkers. Metabolomic studies have generally revealed increased energy requirements for by-products of a hypoxic environment, leading to a characteristic metabolic fingerprint. Here, we discuss the significance of such studies and their potential as a biomarker.

Body composition and Basal metabolic rate in women with type 2 diabetes mellitus

Objective. The aim of this study was to determine which of the seven selected equations used to predict basal metabolic rate most accurately estimated the measured basal metabolic rate. Methods. Twenty-eight adult women with type 2 diabetes mellitus participated in this cross-sectional study. Anthropometric and biochemical variables were measured as well as body composition (by absorptiometry dual X-ray emission) and basal metabolic rate (by indirect calorimetry); basal metabolic rate was also estimated by prediction equations. Results. There was a significant difference between the measured and the estimated basal metabolic rate determined by the FAO/WHO/UNU (P value < 0.021) and Huang et al. (P value ≤ 0.005) equations. Conclusion. The calculations using Owen et al's. equation were the closest to the measured basal metabolic rate.

Evaluation of intragastric vs intraperitoneal glucose tolerance tests in the evaluation of insulin resistance in a rodent model of burn injury and glucagon-like polypeptide-1 treatment

Evaluation of glucose tolerance in rodent models is usually performed after intraperitroneal administration of glucose (intraperitoneal glucose tolerance test [IPGTT]), whereas in humans the test is performed with oral glucose. Hyperglycemia is a major clinical manifestation of burn injury. Our previous studies using IPGTT have demonstrated burn injury-induced insulin resistance and the beneficial effects of glucagon-like polypeptide-1 (GLP-1) in improving insulin resistance. The goal of the present study is to compare the results of these two procedures under 1) burn injury-induced insulin resistance and 2) GLP-1 treatment after burn. Male CD rats were divided into three groups: sham burn, burn, and burn with GLP-1. Blood glucose and plasma insulin levels were measured during intragastric glucose tolerance test (IGGTT) on day 6 after 40% of full-thickness burn injury. The results were compared with our previous IPGTT. Blood glucose curves for IGGTT and IPGTT showed a similar pattern. However, IGGTT demonstrated a significant lower level of maximal blood glucose when compared with IPGTT. This was accompanied by higher peak insulin levels in sham burn and burn groups. In contrast, peak insulin levels of each burn with GLP-1 group were similar. 1) Both IPGTT and IGGTT demonstrated burn injury-induced insulin resistance and the efficacy of GLP-1 for reducing hyperglycemia after burn injury. 2) The observed differences in the plasma glucose and insulin levels between IGGTT and IPGTT suggest that endogenously produced GLP-1 during the IGGTT may play a role in ameliorating insulin resistance after burn injury.

Biphasic changes (overreduction and overoxidation) of plasma redox status and clinical implications in early stage of severe burns

PURPOSE

Although the changes of redox status in the early stage of severe burns are considered to be associated with the disease progression, whereas antioxidant therapy cannot improve the prognosis, the characteristics and mechanisms of dynamic change of redox status related with the disease progression deserve further study.

METHODS

Blood redox potential (ORP) values (ΔORP value was adopted), plasma uric acid (UA) levels, and the inflammation-related indicators of 67 burn patients were dynamically monitored in the early stage.

RESULTS

Compared with healthy persons, the results revealed the biphasic changes of redox status in the early stage after burns, and both of them were closely related to the prognosis of severe burns. Overreduction status and overoxidation status were related to the dynamic changes of plasma UA level and the inflammation-related indicators of severe burns. In addition, the change of ΔORP value was found to associate with the traditional prognostic markers.

CONCLUSIONS

This study firstly revealed the excessive, biphasic changes of redox status and clinical implications in the early stage of severe burns, providing a new viewpoint for early pathological changes of severe burns and will be helpful for corresponding early treatment. ΔORP value also appears to be a potential early prognostic marker.

Nutritional care of the obese adult burn patient: a U.K. Survey and literature review

Obesity is an emerging healthcare problem and affects an increasing number of burn patients worldwide. An email survey questionnaire was constructed and distributed among the 16 U.K. burn services providing adult inpatient facilities to investigate nutritional practices in obese thermally injured patients. Responses received from all dieticians invited to participate in the study were analyzed, and a relevant literature review of key aspects of nutritional care is presented. The majority of services believe that obese patients warrant a different nutritional approach with specific emphasis to avoid overfeeding. The most common algebraic formulae used to calculate calorific requirements include the Schofield, Henry, and modified Penn State equations. Indirect calorimetry despite being considered the "criterion standard" tool to calculate energy requirements is not currently used by any of the U.K. burn services. Gastric/enteral nutrition is initiated within 24 hours of admission in the services surveyed, and a variety of different practices were noted in terms of fasting protocols before procedures requiring general anesthesia/sedation. Hypocaloric regimens for obese patients are not supported by the majority of U.K. facilities, given the limited evidence base supporting their use. The results of this survey outline the wide diversity of dietetic practices adopted in the care of obese burn patients and reveal the need for further study to determine optimal nutritional strategies.

The endocrine response to severe burn trauma

The endocrine system is frequently altered after a major burn trauma. Besides the endocrine response to stress characterized by hypercortisolism, several hypothalamus-hypophysis-target gland axes are rapidly perturbed within a few days. These alterations can persist in the long term and deserve an appropriate treatment. Disturbances in water clearance and glucidic metabolism are also common and need to be diagnosed and corrected to decrease morbidity in such patients. Bone and mineral metabolism is deeply compromised and requires correction of mineral abnormalities in order to improve symptoms and prevent bone loss. No large prospective and/or intervention trials are available to date to elaborate age-related, evidence-based recommendations to monitor and treat burn-related endocrine alterations.

Burn injuries in children and the use of biological dressings

Burns represent a significant cause of morbidity and mortality in children. In this article, a case discussion will serve as a platform for discussing the evaluation and treatment of burns in children. Use of various burn dressings such as hydrocolloids, polyurethane films, hydrogels, biosynthetic skin dressing, and biological dressings will be discussed.

Targeting the redox balance in inflammatory skin conditions

Reactive oxygen species (ROS) can be both beneficial and deleterious. Under normal physiological conditions, ROS production is tightly regulated, and ROS participate in both pathogen defense and cellular signaling. However, insufficient ROS detoxification or ROS overproduction generates oxidative stress, resulting in cellular damage. Oxidative stress has been linked to various inflammatory diseases. Inflammation is an essential response in the protection against injurious insults and thus important at the onset of wound healing. However, hampered resolution of inflammation can result in a chronic, exaggerated response with additional tissue damage. In the pathogenesis of several inflammatory skin conditions, e.g., sunburn and psoriasis, inflammatory-mediated tissue damage is central. The prolonged release of excess ROS in the skin can aggravate inflammatory injury and promote chronic inflammation. The cellular redox balance is therefore tightly regulated by several (enzymatic) antioxidants and pro-oxidants; however, in case of chronic inflammation, the antioxidant system may be depleted, and prolonged oxidative stress occurs. Due to the central role of ROS in inflammatory pathologies, restoring the redox balance forms an innovative therapeutic target in the development of new strategies for treating inflammatory skin conditions. Nevertheless, the clinical use of antioxidant-related therapies is still in its infancy.

17β-Estradiol reappropriates mass lost to the hypermetabolic state in thermally injured rats

BACKGROUND

The hypermetabolic response to severe thermal injury is unlike any physiologic response seen in medicine. While some parallels can be drawn to shock and sepsis states, this response is typified by its intensity and duration. Our group has been interested in the myriad effects of estrogens after injury, specifically the ability of estrogens to reduce inflammatory responses. Given this, and the known link between severe inflammation and the hypermetabolic response, we examined the effects of a single dose of 17β estradiol administered after a severe thermal injury in rats.

METHODS

Twelve male Sprague-Dawley rats were subject to either a sham burn or a 40% total body surface area burn, followed by fluid resuscitation. Burned animals were divided into a vehicle and treatment group, with injections given 15 min after the injury. Animals were monitored for a period of 45 d, with markers of hypermetabolism (weight, fecal output, food intake, and serum insulin and glucose) measured daily.

RESULTS

We identified a significant difference in daily measured weights between the burned groups. We observed a sparing of body mass during the acute phase lasting 2 wk after the injury and an improved recovery phase during the remainder of the study. Glucose and insulin levels during the first week of the study did not differ between the treatment groups.

CONCLUSION

Estrogen may have a role in preserving body mass after severe thermal injury. Further studies are required to determine if this spared body mass composition.

Evolutionary medicine and chronic inflammatory state--known and new concepts in pathophysiology

During the last 10 years, a series of exciting observations has led to a new theory of pathophysiology using insights from evolutionary biology and neuroendocrine immunology to understand the sequelae of chronic inflammatory disease. According to this theory, disease sequelae can be explained based on redirection of energy-rich fuels from storage organs to the activated immune system. These disease sequelae are highly diverse and include the following: sickness behavior, anorexia, malnutrition, muscle wasting–cachexia, cachectic obesity, insulin resistance with hyperinsulinemia, dyslipidemia, increase of adipose tissue near inflamed tissue, alterations of steroid hormone axes, elevated sympathetic tone and local sympathetic nerve fiber loss, decreased parasympathetic tone, hypertension, inflammation-related anemia, and osteopenia. Since these disease sequelae can be found in many animal models of chronic inflammatory diseases with mammals (e.g., monkeys, mice, rats, rabbits, etc.), the evolutionary time line goes back at least 70 million years. While the initial version of this theory could explain prominent sequelae of chronic inflammatory disease, it did not however address two features important in the pathogenesis of immune-mediated diseases: the time point when an acute inflammatory disease becomes chronic, and the appearance of hypertension in chronic inflammation. To address these aspects more specifically, a new version of the theory has been developed. This version defines more precisely the moment of transition from acute inflammatory disease to chronic inflammatory disease as a time in which energy stores become empty (complete energy consumption). Depending on the amount of stored energy, this time point can be calculated to be 19–43 days. Second, the revised theory addresses the mechanisms of essential hypertension since, on the basis of water loss, acute inflammatory diseases can stimulate water retention using a positively selected water retention system (identical to the energy provision system). In chronic smoldering inflammation, however, there is no increased water loss. In contrast, there is increased water generation in inflamed tissue and inflammatory cells, and the activation of the water retention system persists. This combination leads to a net increase of the systemic fluid volume, which is hypothesized to be the basis of essential hypertension (prevalence in adults 22–32%).

The effects of injury magnitude on the kinetics of the acute phase response

BACKGROUND

The acute-phase response (APR) is critical to the body's ability to successfully respond to injury. A murine model of closed unilateral femur fractures and bilateral femur fracture were used to study the effect of injury magnitude on this response.

METHODS

Standardized unilateral femur fracture and bilateral femur fracture in mice were performed. The femur fracture sites, livers, and serum were harvested over time after injury. Changes in mRNA expression of cytokines, hepatic acute-phase proteins, and serum cytokines overtime were measured.

RESULTS

There was a rapid and short-lived hepatic APR to fracture injuries. The overall pattern in both models was similar. Both acute-phase proteins' mRNA (fibrinogen-γ and serum amyloid A-3) showed increased mRNA expression over baseline within the first 48 hours and their levels positively correlated with the extent of injury. However, increased severity of injury resulted in a delayed induction of the APR. A similar effect on the gene expression of cytokines (interleukin [IL]-1β, IL-6, and tumor necrosis factor-α) at the fracture site was seen. Serum IL-6 levels increased with increased injury and showed no delay between injury models.

CONCLUSIONS

Greater severity of injury resulted in a delayed induction of the liver's APR and a diminished expression of cytokines at the fracture site. Serum IL-6 levels were calibrated to the extent of the injury, and changes may represent mechanisms by which the local organ responses to injury are regulated by the injury magnitude.

Pathway analysis of liver metabolism under stressed condition

Pathway analysis is a useful tool which reveals important metabolic network properties. However, the big challenge is to propose an objective function for estimating active pathways, which represent the actual state of network. In order to provide weight values for all possible pathways within the metabolic network, this study presents different approaches, considering the structural and physiological properties of the metabolic network, aiming at a unique decomposition of the flux vector into pathways. These methods were used to analyze the hepatic metabolism considering available data sets obtained from the perfused livers of fasted rats receiving burn injury. Utilizing unique decomposition techniques and different fluxes revealed that higher weights were always attributed to short pathways. Specific pathways, including pyruvate, glutamate and oxaloacetate pools, and urea production from arginine, were found to be important or essential in all methods and experimental conditions. Moreover the pathways, including serine production from glycine and conversion between acetoacetate and B-OH-butyrate, were assigned higher weights. Pathway analysis was also used to identify the main sources for the production of certain products in the hepatic metabolic network to gain a better understanding of the effects of burn injury on liver metabolism.

The biology of burn injury

Burn injury is a complex traumatic event with various local and systemic effects, affecting several organ systems beyond the skin. The pathophysiology of the burn patient shows the full spectrum of the complexity of inflammatory response reactions. In the acute phase, inflammation mechanism may have negative effects because of capillary leak, the propagation of inhalation injury and the development of multiple organ failure. Attempts to mediate these processes remain a central subject of burn care research. Conversely, inflammation is a necessary prologue and component in the later-stage processes of wound healing. In this review, we are attempting to present the current science of burn wound pathophysiology and wound healing. We also describe the evolution of innovative strategies for burn management.

The role of hyperglycemia in burned patients: evidence-based studies

Severely burned patients typically experience a systemic response expressed as increased metabolism, inflammation, alteration of cardiac and immune function, and associated hyperglycemia. Hyperglycemia has been associated with an increased risk of morbidity and mortality in critically ill patients. Until recently and for many years, hyperglycemia has been expectantly managed and considered a normal and desired response of an organism to stress. However, findings reported from recent studies now suggest beneficial effects of intensive insulin treatment of critically ill patients. The literature on the management of hyperglycemia in severely burned patients is sparse, with most of the available studies involving only small numbers of burned patients. The purpose of this article is to describe the pathophysiology of hyperglycemia after severe burns and to review the available literature on the outcome of intensive insulin treatment and other anti-hyperglycemic modalities in burned patients in an evidence-based medical approach.

Molecular characterization and quantification using state of the art solid-state adiabatic TOBSY NMR in burn trauma

We describe a novel solid-state nuclear magnetic resonance (NMR) method that maximizes the advantages of high-resolution magic-angle-spinning (HRMAS), relative conventional liquid-state NMR approaches, when applied to intact biopsies of skeletal muscle specimens collected from burn trauma patients. This novel method, termed optimized adiabatic TOtal through Bond correlation SpectroscopY (TOBSY) solid-state NMR pulse sequence for two-dimensional (2D)¹H-¹H homonuclear scalar-coupling longitudinal isotropic mixing, was demonstrated to provide a 40–60% improvement in signal-to-noise ratio (SNR) relative to its liquid-state analogue TOCSY (TOtal Correlation SpectroscopY). Using 1-and 2-dimensional HRMAS NMR experiments, we identified several metabolites in burned tissues. Quantification of metabolites in burned tissues showed increased levels of lipid compounds, intracellular metabolites (e.g., taurine and phosphocreatine) and substantially decreased water-soluble metabolites (e.g., glutathione, carnosine, glucose, glutamine/glutamate and alanine). These findings demonstrate that HRMAS NMR Spectroscopy using TOBSY is a feasible technique that reveals new insights into the pathophysiology of burn trauma. Moreover, this method has applications that facilitate the development of novel therapeutic strategies.

n-3 Fatty acid supplementation in burned paediatric patients

AIM

To determine the effect of dietary supplementation with n-3 fatty acids (FA) in paediatric burned patients who had less than 20% of total body surface affected.

METHODS

Burned patients were randomly assigned into two groups, one of them received a supplement of n-3 FA during 5 weeks; the other group was considered as not n-3 supplemented burned group. A third group of no burned patients was selected as control. Blood samples were collected at admission and in burned groups at the final of the study. Plasma and erythrocyte phospholipid FA composition and some biochemical parameters related to the clinical evolution: total plasma proteins and C3 and C4 complement proteins were determined.

RESULTS

In the early post-burn patients, there is an increase in saturated and monounsaturated FAs in plasma phospholipids, and a decrease in polyunsaturated FAs compared with control. These alterations are in favour of proinflammatory response to burn injury. In n-3 FA supplemented group, these changes were further reverted, and a favourable response in the amount of total plasma proteins and in C3 and C4 proteins of the complement system was demonstrated.

CONCLUSION

Dietary n-3 FA supplementation might be beneficial for patients suffering thermal injury.

The hepatic response to thermal injury: is the liver important for postburn outcomes?

Thermal injury produces a profound hypermetabolic and hypercatabolic stress response characterized by increased endogenous glucose production via gluconeogenesis and glycogenolysis, lipolysis, and proteolysis. The liver is the central body organ involved in these metabolic responses. It is suggested that the liver, with its metabolic, inflammatory, immune, and acute phase functions, plays a pivotal role in patient survival and recovery by modulating multiple pathways following thermal injury. Studies have evaluated the role and function of the liver during the postburn response and showed that liver integrity and function are essential for survival, and that hepatic acute phase proteins are strong predictors for postburn survival. This review discusses these studies and delineates the pivotal role of the liver in patients following severe thermal injury.

Oxandrolone treatment in adults with severe thermal injury

Severe thermal injury is associated with hypermetabolism and hypercatabolism, leading to skeletal muscle breakdown, lean body mass loss, weight loss, and negative nitrogen balance. Muscle protein catabolism in patients with severe thermal injury is the result of stress-induced increased release of cytokines and counterregulatory hormones. Coupled with decreased serum anabolic hormone concentrations such as testosterone and growth hormone along with the presence of insulin resistance, anabolism in patients with severe thermal injury is inefficient or impossible during the acute postburn period. This causes difficulty in restoring lean body mass and regaining lost body weight, as well as poor healing of the burn wound and delayed patient recovery. Oxandrolone, a synthetic derivative of testosterone, has been used in adult patients with severe thermal injury to enhance lean body mass accretion, restore body weight, and accelerate wound healing. In clinical studies, oxandrolone 10 mg orally twice/day improved wound healing, restored lean body mass, and accelerated body weight gain. During the rehabilitation period, oxandrolone therapy with adequate nutrition and exercise improved lean body mass, increased muscle strength, and restored body weight. However, most data on oxandrolone use in adult patients with severe thermal injury are derived from single-center studies, many of which enrolled a relatively small number of subjects and some of which had a poor design. Multicenter, prospective, randomized studies are needed to better define the optimal oxandrolone dosage and to confirm the efficacy and safety of this drug in adult patients with severe thermal injury.

Nutritional therapy for burns in children and adults

Burns are a serious injury that requires optimal nutritional support. This review discusses the nutritional care for adults and children with major burns. A burned patient's metabolism is greatly accelerated with increased requirements for energy, carbohydrates, proteins, fats, vitamins, minerals, and antioxidants. Early nutrition by parenteral and enteral feedings is vital. Careful assessment of the nutritional state of the burn patient is also important to reduce infection, recovery time, and long-term sequelae.

Emergency treatment of severely burned pediatric patients: current therapeutic strategies

Burn trauma represents a devastating injury and remains as one of the leading causes of mortality and morbidity in children. Effective prevention strategies, advances in therapeutic techniques, based on an improved understanding of fluid resuscitation, appropriate infection control and improved treatment of inhalation injury, enhanced wound coverage, better nutritional regimens, advanced support of the hypermetabolic response to injury and improved glucose control, have significantly improved the clinical outcome of this unique patient population over the past years. This article aims to outline the current and emerging therapeutic strategies for the treatment of severely burned pediatric patients in the emergency department or initial phase of the intensive care unit.

Oxidative stress and anti-oxidative mobilization in burn injury

A severe burn is associated with release of inflammatory mediators which ultimately cause local and distant pathophysiological effects. Mediators including Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) are increased in affected tissue, which are implicated in pathophysiological events observed in burn patients. The purpose of this article is to understand the role of oxidative stress in burns, in order to develop therapeutic strategies. All peer-reviewed, original and review articles published in the English language literature relevant to the topic of oxidative stress in burns in animals and human subjects were selected for this review and the possible roles of ROS and RNS in the pathophysiology of burns are discussed. Both increased xanthine oxidase and neutrophil activation appear to be the oxidant sources in burns. Free radicals have been found to have beneficial effects on antimicrobial action and wound healing. However following a burn, there is an enormous production of ROS which is harmful and implicated in inflammation, systemic inflammatory response syndrome, immunosuppression, infection and sepsis, tissue damage and multiple organ failure. Thus clinical response to burn is dependent on the balance between production of free radicals and its detoxification. Supplementation of antioxidants in human and animal models has proven benefit in decreasing distant organ failure suggesting a cause and effect relationship. We conclude that oxidative damage is one of the mechanisms responsible for the local and distant pathophysiological events observed after burn, and therefore anti-oxidant therapy might be beneficial in minimizing injury in burned patients.