Impaired zinc and copper status in children with burn injuries: need to reassess nutritional requirements

The model pH-controlled delivery system based on gelatin-tannin hydrogels containing ferrous ascorbate: iron releasein vitro

Hydrogels have become an essential class among all biomaterials. The specialized biomaterials are highly valued in the field of biomedical applications. One of the problems in wound management is local microelement deficiency associated with extensive wound lesions. The significant lack of elemental iron in the human body leads to serious consequences and prolongs treatment. The synthesis of gelatin-tannin hydrogels with ion delivery function is proposed in this study. The ability to release ions in low acid solution is a sphere of great interest. The pH drop in the wound cavity is usually associated with the contamination of some bacterial cultures. pH-controlled delivery of iron in buffer solutions (рН = 5.5/6.4/7.4) was considered for these hydrogels. The kinetics of iron release was determined by visible spectroscopy. Theoretical models were applied to describe the process of ion delivery. The structure of materials was examined by IR-spectroscopy and demonstrated the incorporation of ferrous ascorbate into hydrogel matrix. Thermal analysis was used to point out the key differences in thermal behavior by isoconversional methods (Flynn-Wall-Ozawa/Kissinger-Akahira-Sunose). The mechanical properties of the materials have been studied. The effect of iron ascorbate on polymer network parameters was discussed. The current study demonstrated the possibility of obtaining gelatin-tannin hydrogels for pH-dependent iron delivery. That provides future perspectives to expand the set of releasing microelements for biomedical applications.

The Extent of Burn Injury Significantly Affects Serum Micro- and Macroelement Concentrations in Patients on the First Day of Hospitalisation

Burns exceeding 30% of total body surface area (TBSA) result in considerable hypovolemia coupled with the formation and release of inflammatory mediators, leading to subsequent systemic effects known as burn shock. Because of plasma exudation and the associated losses of large quantities of minerals, severe burns can lead to nutritional deficiencies and consequently disrupt homeostasis and metabolism of the entire body. The study group comprised 62 patients, who were divided into 3 groups according to the severity of burns. Serum samples were tested for concentrations of Ca, Mg, Mn, P, K, Zn, Cu, Fe, Se, Na, Cr, Ni, and Al. The mineral concentrations in serum of patients with burn injuries differ significantly from reference values, but this is not affected by the extent of the body burn. There are statistically significant decreases in serum concentrations of elements important for antioxidant protection (Zn, Cu, Se), and significant increases in the concentrations of toxic elements (Al and Ni), which may aggravate the effects associated with the state of burn shock. The Spearman rank correlation analysis did not reveal any statistically significant relationships between the serum concentrations of Mn, Ni, Al, K, Na, P, Mg, Zn, Se, Cr and the affected body surface area and severity of the burn—the values were at the lower end of the reference range. The obtained results indicate that proper nutrition, including elements replenishment, is extremely important in the recovery process of burn patients and time to nutrition is an important factor affecting patient survival after severe burn.

Development of Multi-epitope Subunit Vaccine Against Pseudomonas aeruginosa Using OprF/OprI and PopB Proteins

Background: The emerging problem of antibiotic resistance in Pseudomonas aeruginosa is a global health concern; hence, revealing innovative therapeutic approaches (such as designing an immunogenic vaccine candidate) is needed. There is no evidence of the availability of an effective vaccine that can combat the infection caused by this microorganism. Objectives: This research was conducted to develop a potential chimeric vaccine against P. aeruginosa using reverse vaccinology approaches. Methods: The present vaccine candidate comprised outer membrane protein F and I (OprF/OprI) and PopB with appropriate linkers. After applying meticulous immune-informatics investigation, the multi-epitope vaccine was created, including helper T lymphocyte (HTL), cytotoxic T lymphocyte (CTL), interferon gamma (IFN-γ), and interleukin 4 (IL-4) epitopes. Then, the physicochemical characteristics, allergenicity, toxicity, and antigenicity were analyzed. After investigating the secondary structure, the tertiary structure (3D) model was generated, refined, and validated via computational methods. Besides, the strong protein-ligand interaction and stability between the vaccine candidate and toll-like receptor 4 (TLR4) were determined via molecular docking and dynamics analyses. Moreover, in silico cloning accompanied by pET-22b (+) was used to achieve high translation efficiency. Results: Our results presumed that the chimeric-designed vaccine was thermostable and contained optimal physicochemical properties. This vaccine candidate was nontoxic and highly soluble and had stable protein and TLR4 interaction, adequately overexpressed in Escherichia coli. Overall, it could induce immune responses and repress this microorganism. Conclusions: Therefore, to inhibit Pseudomonas infections experimentally, the efficacy and safety of the vaccine design need to be validated.

Bioelements in the treatment of burn injuries - The complex review of metabolism and supplementation (copper, selenium, zinc, iron, manganese, chromium and magnesium)

Appropriate nutrition is a key component of burn treatment and should be regarded as an integral part of the therapeutic process in burn patients. A nutritional intervention plan should not only allow for adequate quantities of energy and protein but also carefully consider the supply of macro- and micronutrients. As a result of the severe inflammatory response, oxidative stress, and hypermetabolic state, accompanied by often extensive exudation in burn patients, there is a considerable loss of macro- and micronutrients, including essential trace elements. This leads to certain complications, involving e.g. more frequent infections and impaired wound healing. Our current body of knowledge is still insufficient, and the studies carried out to date focus for the most part on the imbalances in trace elements, such as copper (Cu), selenium (Se), and zinc (Zn). Nevertheless, there are many other trace elements involved in immune functions, regulating gene expression or antioxidant defense, and many of those have not been properly investigated in a clinical setting. Due to the insufficient amount of unambiguous literature data and relatively few, often dated, studies carried out with small patient groups, further evaluation of macro- and microelements in burn patients seems indispensable, e.g. to bring up to date local nutritional protocols.

Copper Deficiency: Causes, Manifestations, and Treatment

BACKGROUND

The metabolism of the essential trace element copper remains incompletely understood and, until recently, nearly ignored in acute medicine. Menkes disease was for long the only known copper deficiency condition, but several case reports and investigations conducted over the last 2 decades have shown that deficiency is more frequent than previously suspected, with devastating individual consequences and potential public health consequences. The copper needs in healthy individuals are 0.9 mg/d, which translates to 0.3 mg/d intravenously in parenteral nutrition; the present review aims at gathering actual knowledge.

METHOD AND RESULTS

A review of literature was conducted in PubMed and Cochrane systematic reviews to identify the most recent information about copper deficiency and generate a narrative review. Copper deficiency has hereditary and acquired origins, the latter being the most frequent. Clinical manifestations are nonspecific but affect all organs and systems, particularly the hematologic (anemia) and the neurologic (myeloneuropathy) systems. Deficiency also affects the cardiovascular, cutaneous, and immune systems. Severe copper deficiency due to reduced absorption after bariatric bypass surgery has become frequent.

CONCLUSION

Deficiency is more frequent than previously recognized, probably because of changing nutrition patterns but also because of some treatments that have become very common such as bypass bariatric surgery and, in acute medicine, prolonged continuous renal replacement therapy. The patients may present with severe hematologic and neurologic complications that go untreated because copper deficiency was not considered in the differential diagnosis: These complications often need active intravenous repletion with doses 4-8 times the usual nutrition recommendations.

Bone metabolism in pediatric burned patients: A review

Severe burns in children can lead to growth delays, bone loss, and wasting of lean body mass and muscle with subsequent long-term effects such as osteoporosis. The following review examines 11 randomized, placebo-controlled, prospective clinical trials in pediatric burns between 1995 and 2017. These studies included approximately 250 burned children, and they were conducted to evaluate the impact of severe burn on markers of bone formation and bone metabolism. Some trials also analyzed current therapy regimens such as pamidronate and vitamin D. The clinical utility of these outlined biomarkers is uncertain with regard to acute burn care, as the current literature remains unclear. This review thus serves to address the impact of severe burn on markers of bone formation and bone metabolism in pediatric patients but will not focus on the clinical utility of the markers. The aim of this review is to summarize the findings of the trials to guide the future care of burned patients to maximize bone recovery.

Multiple Micronutrient Plasma Level Changes Are Related to Oxidative Stress Intensity in Critically Ill Children

OBJECTIVES

Micronutrient supplementation in critically ill adults remains controversial. In the pediatric setting, the impact of oxidative stress on the overall micronutrient status has been poorly explored, due to the limited number of studies and to confounding factors (i.e., malnutrition or extra losses). In order to better understand this phenomenon, we aim to describe micronutrient status, focusing on seven micronutrients, in well-nourished critically ill children presenting with severe oxidative stress.

DESIGN

Prospective, transversal, observational, single-center study.

SETTING

PICU, and anesthesiology department, Lyon, France.

PATIENTS

Three groups of patients were clinically defined: severe oxidative stress PICU group (at least two organ dysfunctions), moderate oxidative stress PICU group (single organ dysfunction), and healthy control group (prior to elective surgery); oxidative stress intensity was controlled by measuring plasma levels of glutathione peroxidase and glutathione. Children presenting any former condition leading to micronutrient deficiency were excluded (malnutrition, external losses).

INTERVENTIONS

Plasma levels of selenium, zinc, copper, vitamin A, vitamin E, vitamin C, and β-carotene were measured in PICU oxidative stress conditions and compared with those of healthy children.

MEASUREMENTS AND MAIN RESULTS

Two hundred one patients were enrolled (51, 48, and 102 in severe, moderate, and healthy control groups, respectively). Median age was 7.1 years (interquartile range, 2.1-13.8 yr). There was a significant trend (p < 0.02) toward plasma level decrease of six micronutrients (selenium, zinc, copper, vitamin E, vitamin C, and β-carotene) while oxidative stress intensity increased. Biological markers of oxidative stress (glutathione peroxidase and glutathione) were in accordance with the clinical definition of the three groups.

CONCLUSIONS

A multiple micronutrient deficiency or redistribution occurs in critically ill children presenting with severe oxidative stress. These findings will help to better identify children who might benefit from micronutrient supplementation and to design adapted supplementation trials in this particular setting.

Progress in TiO2 nanotube coatings for biomedical applications: a review

Titanium dioxide nanotubes (TNTs) have drawn wide attention and been extensively applied in the field of biomedicine, due to their large specific surface area, good corrosion resistance, excellent biocompatibility, and enhanced bioactivity. This review describes the preparation of TNTs and the surface modification that entrust the nanotubes with better antibacterial property and enhanced osteoblast adhesion, proliferation, and differentiation. Considering the contact between TNTs' surface and surrounding tissues after implantation, the interactions between TNTs (with properties including their diameter, length, wettability, and crystalline phase) and proteins, platelets, bacteria, and cells are illustrated. The state of the art in the applications of TNTs in dentistry, orthopedic implants, and cardiovascular stents are introduced. In particular, the application of TNTs in biosensing has attracted much attention due to its ability for the rapid diagnosis of diseases. Finally, the difficulties and challenges in the practical application of TNTs are also discussed.

Antibacterial properties of nanostructured Cu–TiO2surfaces for dental implants

The influence of copper derived TiO₂surfaces (nCu–nT-TiO₂) on the death of nosocomialStaphylococcus aureus(Sa) andEscherichia coli(Ec), was investigated.

Antioxidant Micronutrients in Major Trauma and Burns: Evidence and Practice

There has been a growing interest in micronutrients as a result of their essential role in endogenous antioxidant defense mechanisms and immunity. Critically ill burn and trauma patients are characterized by an increased free radical production, which is proportional to the severity of the injury. In addition, they are at high risk of negative trace element balances, which contribute to the imbalance in endogenous antioxidant capacity and the extension of primary lesions. Although selenium, zinc, and vitamin C and E status are altered in all injured patients, patients with major burns are unique for having copper deficiency. In major burns, high-dose ascorbic acid for 24 hours achieves reduction of resuscitation fluid requirements by endothelial antioxidant mechanisms both in animal models and in 1 human trial. Supplementation trials in trauma and burns including selenium and zinc have shown that early provision of micronutrients improves recovery. Vitamin supplementation trials without selenium have not achieved definitive effects. The human studies show that reinforcing antioxidant defenses early in the course of major injury is rational and that substituting the large initial micronutrient losses of selenium and zinc is safe in trauma, as is the addition of copper in burns. The IV route seems the only way to deliver the doses required to obtain a clinical effect.

Why so little effort to study anti-oxidant therapy in burns?

Given that oxidative stress is an inherent response to burn injury, it is puzzling as to why investigation into anti-oxidant therapy as an adjunct to burn treatment has been limited. Both the inflammatory response and the stress response to burn injury involve oxidative stress, and there has been some limited success in studies using gamma tocopherol and selenium to improve certain consequences of burns. Much remains to be done to investigate the number, doses and combinations of anti-oxidants, their efficacy, and limitations in improving defined outcomes after burn injury.

Effect of Human Burn Wound Exudate on Pseudomonas aeruginosa Virulence

Burn wound sepsis is currently the main cause of morbidity and mortality after burn trauma. Infections by notorious pathogens such as Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter baumannii impair patient recovery and can even lead to fatality. In this study, we investigated the effect of burn wound exudates (BWEs) on the virulence of those pathogens. BWEs were collected within 7 days after burn trauma from 5 burn patients. We first monitored their effect on pathogen growth. In contrast to A. baumannii and S. aureus, P. aeruginosa was the only pathogen able to grow within these human fluids. Expression of typical virulence factors such as pyocyanin and pyoverdine was even enhanced compared the levels seen with standard laboratory medium. A detailed chemical composition analysis of BWE was performed, which enabled us to determine the major components of BWE and underline the metabolic modifications induced by burn trauma. These data are essential for the development of an artificial medium mimicking the burn wound environment and the establishment of an in vitro system to analyze the initial steps of burn wound infections. IMPORTANCE Microbial infection of severe burn wounds is currently a major medical challenge. Of the infections by bacteria able to colonize such injuries, those by Pseudomonas aeruginosa are among the most severe, causing major delays in burn patient recovery or leading to fatal issues. In this study, we investigated the growth properties of several burn wound pathogens in biological fluids secreted from human burn wounds. We found that P. aeruginosa strains were able to proliferate but not those of the other pathogens tested. In addition, burn wound exudates (BWEs) stimulate the expression of virulence factors in P. aeruginosa. The chemical composition analysis of BWEs enabled us to determine the major components of these fluids. These data are essential for the development of an artificial medium mimicking the burn wound environment and for in vitro analysis of the initial step in the development of burn wound infections.

Synthesis and antimicrobial activity of monodisperse copper nanoparticles

Metallic monodisperse copper nanoparticles at a relatively high concentration (300 ppm CuNPs) have been synthesized by the reduction of copper salt with hydrazine in the aqueous SDS solution. The average particles size and the distribution size were characterized by Dynamic Light Scattering (DLS), Nanosight-Nanoparticle Tracking Analysis (NTA). The morphology and structure of nanoparticles were investigated using Scanning Electron Microscopy (SEM). The chemical composition of the copper nanoparticles was determined by X-ray Photoelectron Spectroscopy (XPS). Monodisperse copper nanoparticles with average diameter 50 nm were received. UV/vis absorption spectra confirmed the formation of the nanoparticles with the characteristic peak 550 nm. The antimicrobial studies showed that the copper nanoparticles had high activity against Gram-positive bacteria, standard and clinical strains, including methicillin-resistant Staphylococcus aureus, comparable to silver nanoparticles and some antibiotics. They also exhibited antifungal activity against Candida species.

Global perspectives on trace element requirements

Trace elements are inorganic constituents of the human body present in concentrations less than 50mg/kg body weight. An exception is iron that is found in slightly higher amounts, 60 mg/kg body weight, but it is classified within this category due to its physiological roles. Requirements of trace elements can vary according to age, gender, growth, body composition, genetics, pregnancy, lactation, wound healing and burns, alcohol abuse, infections, and diseases (anemia, coronary artery, Keshan, Kashin-Beck). Additionally, interactions may occur with dietary factors, such as other minerals (iron versus copper), phytates (zinc), oxalates (iron), fiber (manganese), and polyphenolic compounds (molybdenum). On a global basis, requirements can vary according to soil and geographical location, food preparation and processing, food accessibility, cultural practices (geophagia) and pollution. Furthermore, global differences exist in body composition, ethnicity, and age of menarche.

Micronutrients after burn injury: a review

Supplementation of micronutrients after burn injury is common practice in order to fight oxidative stress, support the immune system, and optimize wound healing. Assessing micronutrient status after burn injury is difficult because of hemodilution in the resuscitation phase, redistribution of nutrients from the serum to other organs, and decreases in carrier proteins such as albumin. Although there are many preclinical data, there are limited studies in burn patients. Promising research is being conducted on combinations of micronutrients, especially via the intravenous route.

Sputum containing zinc enhances carbapenem resistance, biofilm formation and virulence of Pseudomonas aeruginosa

Pseudomonas aeruginosa chronic lung infections are the leading cause of mortality in cystic fibrosis patients, a serious problem which is notably due to the numerous P. aeruginosa virulence factors, to its ability to form biofilms and to resist the effects of most antibiotics. Production of virulence factors and biofilm formation by P. aeruginosa is highly coordinated through complex regulatory systems. We recently found that CzcRS, the zinc and cadmium-specific two-component system is not only involved in metal resistance, but also in virulence and carbapenem antibiotic resistance in P. aeruginosa. Interestingly, zinc has been shown to be enriched in the lung secretions of cystic fibrosis patients. In this study, we investigated whether zinc might favor P. aeruginosa pathogenicity using an artificial sputum medium to mimic the cystic fibrosis lung environment. Our results show that zinc supplementation triggers a dual P. aeruginosa response: (i) it exacerbates pathogenicity by a CzcRS two-component system-dependent mechanism and (ii) it stimulates biofilm formation by a CzcRS-independent mechanism. Furthermore, P. aeruginosa cells embedded in these biofilms exhibited increased resistance to carbapenems. We identified a novel Zn-sensitive regulatory circuit controlling the expression of the OprD porin and modifying the carbapenem resistance profile. Altogether our data demonstrated that zinc levels in the sputum of cystic fibrosis patients might aggravate P. aeruginosa infection. Targeting zinc levels in sputum would be a valuable strategy to curb the increasing burden of P. aeruginosa infections in cystic fibrosis patients.

Bone mineralization in children with Wilson's disease

BACKGROUND

The goal of this study was to determine bone mineralization in children with Wilson's disease (WD).

METHODS

Twenty-seven patients (16 males) and two age- and gender-matched healthy children for each patient were enrolled in the study. Bone mineral content (BMC, grams) and density (BMD, g/cm(2)) at lumbar 1-4 vertebrae were measured by dual-energy X-ray absorptiometry. Urinary calcium excretion was calculated in 19 patients. The effect of cirrhosis and hypercalciuria on BMC and BMD was also evaluated in WD patients.

RESULTS

There was no statistically significant difference between patients and healthy controls regarding mean BMC (33.0 ± 13.9 vs. 35.8 ± 13.8 g) (p = 0.940) and mean BMD values (0.66 ± 0.16 vs. 0.71 ± 0.18 g/cm(2)) (p = 0.269), respectively. Nine (47.4 %) patients had hypercalciuria. Hypercalciuric patients had statistically significant lower BMC and BMD values than those without hypercalciuria. A significant difference continued to be present after age, weight, height, and pubertal stage adjustment was done, but disappeared after weight, height, follow up duration, and pubertal stage adjustment was done. The presence of cirrhosis did not affect BMC and BMD significantly in WD patients.

CONCLUSIONS

BMC and BMD in children with WD were normal. The presence of hypercalciuria but not cirrhosis may affect BMC and BMD negatively in the patients.

Cupric yersiniabactin is a virulence-associated superoxide dismutase mimic

Many Gram-negative bacteria interact with extracellular metal ions by expressing one or more siderophore types. Among these, the virulence-associated siderophore yersiniabactin (Ybt) is an avid copper chelator, forming stable cupric (Cu(II)-Ybt) complexes that are detectable in infected patients. Here we show that Ybt-expressing E. coli are protected from intracellular killing within copper-replete phagocytic cells. This survival advantage is highly dependent upon the phagocyte respiratory burst, during which superoxide is generated by the NADPH oxidase complex. Chemical fractionation links this phenotype to a previously unappreciated superoxide dismutase (SOD)-like activity of Cu(II)-Ybt. Unlike previously described synthetic copper-salicylate (Cu(II)-SA) SOD mimics, the salicylate-based natural product Cu(II)-Ybt retains catalytic activity at physiologically plausible protein concentrations. These results reveal a new virulence-associated adaptation based upon spontaneous assembly of a non-protein catalyst.

Pathogenic adaptations to host-derived antibacterial copper

Recent findings suggest that both host and pathogen manipulate copper content in infected host niches during infections. In this review, we summarize recent developments that implicate copper resistance as an important determinant of bacterial fitness at the host-pathogen interface. An essential mammalian nutrient, copper cycles between copper (I) (Cu(+)) in its reduced form and copper (II) (Cu(2+)) in its oxidized form under physiologic conditions. Cu(+) is significantly more bactericidal than Cu(2+) due to its ability to freely penetrate bacterial membranes and inactivate intracellular iron-sulfur clusters. Copper ions can also catalyze reactive oxygen species (ROS) generation, which may further contribute to their toxicity. Transporters, chaperones, redox proteins, receptors and transcription factors and even siderophores affect copper accumulation and distribution in both pathogenic microbes and their human hosts. This review will briefly cover evidence for copper as a mammalian antibacterial effector, the possible reasons for this toxicity, and pathogenic resistance mechanisms directed against it.

Management of Burns and Anesthetic Implications

Burn injuries are highly complex and affect almost every major organ system in the body. The treatment of burn patients requires the presence of a well-organized team of caregivers who understand the multifaceted consequences of burn injuries and who are adept at coordinating care. An understanding of the multitude of abnormalities that must be addressed helps to guide therapy in these patients. Careful anesthetic and perioperative management of these patients carries special importance in this fragile patient population as a part of their often lengthy recovery and rehabilitation.

Beneficial regulation of fibrillar collagens, heat shock protein-47, elastin fiber components, transforming growth factor-β1, vascular endothelial growth factor and oxidative stress effects by copper in dermal fibroblasts

Skin aging is associated with the loss of the structural collagens and the elastin fiber components that form the extracellular matrix (ECM). It is associated with reduced transforming growth factor-β (TGF-β), angiogenesis and increased oxidative stress. Copper has been incorporated into cosmetics for anti-skin aging. This research investigated the mechanism for the anti-skin aging effect copper ions, from cuprous oxide powders. Dermal fibroblasts were exposed to copper and examined for expression (protein and/or promoter levels) of types I, III, V collagen, heat shock protein-47 (HSP-47), elastin, fibrillin-1, and fibrillin-2, TGF-β1, vascular endothelial growth factor (VEGF), and in addition for membrane damage and lipid peroxidation. The direct antioxidant activity of copper was also determined. The research indicates that copper's anti-skin aging and skin regeneration potential is through its stimulation of ECM proteins, TGF-β1, VEGF, and inhibition of oxidative stress effects at physiological concentrations; and supports its use in cosmetics.

Copper homeostasis at the host-pathogen interface

The trace element copper is indispensable for all aerobic life forms. Its ability to cycle between two oxidation states, Cu(1+) and Cu(2+), has been harnessed by a wide array of metalloenzymes that catalyze electron transfer reactions. The metabolic needs for copper are sustained by a complex series of transporters and carrier proteins that regulate its intracellular accumulation and distribution in both pathogenic microbes and their animal hosts. However, copper is also potentially toxic due in part to its ability to generate reactive oxygen species. Recent studies suggest that the macrophage phagosome accumulates copper during bacterial infection, which may constitute an important mechanism of killing. Bacterial countermeasures include the up-regulation of copper export and detoxification genes during infection, which studies suggest are important determinants of virulence. In this minireview, we summarize recent developments that suggest an emerging role for copper as an unexpected component in determining the outcome of host-pathogen interactions.

Update on the critical care management of severe burns

Care of the severely injured patient with burn requires correct diagnosis, appropriately tailored resuscitation, and definitive surgical management to reduce morbidity and mortality. Currently, mortality rates related to severe burn injuries continue to steadily decline due to the standardization of a multidisciplinary approach instituted at tertiary health care centers. Prompt and accurate diagnoses of burn wounds utilizing Lund-Browder diagrams allow for appropriate operative and nonoperative management. Coupled with diagnostic improvements, advances in resuscitation strategies involving rates, volumes, and fluid types have yielded demonstrable benefits related to all aspects of burn care. More recently, identification of comorbid conditions such as inhalation injury and malnutrition have produced appropriate protocols that aid the healing process in severely injured patients with burn. As more patients survive larger burn injuries, the early diagnosis and successful treatment of secondary and tertiary complications are becoming commonplace. While advances in this area are exciting, much work to elucidate immune pathways, diagnostic tests, and effective treatment regimens still remain. This review will provide an update on the critical care management of severe burns, touching on accurate diagnosis, resuscitation, and acute management of this difficult patient population.

Burns: where has all the calcium (and vitamin D) gone?

A considerable part of the difficulty of determining nutrient requirements in pathologic states is the failure to understand the physiology unique to the specific condition. Here we take the specific example of burns in childhood and discuss the roles of the inflammatory and stress responses to the burn and the consequent transient increased bone resorption followed by osteoblast apoptosis and adynamic bone. This condition leads to a failure of the bone to take up and thus conserve the increased calcium liberated by the acutely increased bone resorption. On top of this mechanism, there is a cytokine-mediated upregulation in the parathyroid gland calcium-sensing receptor that results in hypocalcemic hypoparathyroidism and consequent urinary calcium wasting. As if that were not sufficient, the skin of the burned patient, both scarred area and normal-appearing adjacent skin, convert 7 dehydrocholesterol to pre-vitamin D(3) at a rate that is 20-25% of normal skin and circulating levels of 25-hydroxyvitamin D are chronically low. Thus, burn injury gives rise to calcium wasting, failure of bone to take up excessive calcium, and vitamin D insufficiency to frank deficiency. These and other areas must be addressed before it can be determined how much vitamin D and calcium should be given to a patient with severe burn injury.

Nutrition in burns: Galveston contributions

Aggressive nutrition support is recommended following severe burn injury. Initially, such injury results in a prolonged and persistent hypermetabolic response mediated by a 10- to 20-fold elevation in plasma catecholamines, cortisol, and inflammatory mediators. This response leads to twice-normal metabolic rates, whole-body catabolism, muscle wasting, and severe cachexia. Thus, it is relevant to review the literature on nutrition in burns to adjust/update treatment. Failure to meet the increased substrate requirements may result in impaired wound healing, multiorgan dysfunction, increased susceptibility to infection, and death. Therefore, aggressive nutrition support is essential to ensure adequate burn care, attenuate the hypermetabolic response, optimize wound healing, minimize devastating catabolism, and reduce morbidity and mortality. Here, the authors provide nutrition recommendations gained from prospective trials, retrospective analyses, and expert opinions based on the authors' practices in Galveston, Texas, and Vienna, Austria.

Supplementation of vitamin E, vitamin C, and zinc attenuates oxidative stress in burned children: a randomized, double-blind, placebo-controlled pilot study

The aim of this study was to investigate the effect of supplementation of vitamin E, vitamin C, and zinc on the oxidative stress in burned children. In a prospective double-blind placebo controlled pilot study, 32 patients were randomized as no supplementation (n = 15) or antioxidant supplementation (n = 17) groups. Supplementation consisted of the antioxidant mixture of vitamin C (1.5 times upper intake level), vitamin E (1.35 times upper intake level), and zinc (2.0 times recommended dietary allowance) administered during 7 days starting on the second day of admittance into the hospital. Energy requirement was calculated by the Curreri equation, and protein input was 3.0 g/kg of ideal body mass index (percentile 50). Total antioxidant capacity of plasma and malondialdehyde were used to monitor oxidative stress. The time of wound healing was evaluated as the main clinical feature. Patients (age 54.2 +/- 48.9 months, 65.6% males), who exhibited 15.5 +/- 6.7% of total burn area, showed no differences in age and sex, when compared with controls. Intake of the administered antioxidants was obviously higher in treated subjects (P = .005), and serum differences were confirmed for vitamin E and C, but not for zinc (P = .180). There was a decrease in lipid peroxidation (malondialdehyde level) (P = .006) and an increase in vitamin E concentrations in the antioxidant supplementation group (P = .016). The time of wound healing was lower in the supplemented group (P < .001). The antioxidant supplementation through vitamin E and C and the mineral zinc apparently enhanced antioxidant protection against oxidative stress and allowed less time for wound healing.

A role for the ATP7A copper-transporting ATPase in macrophage bactericidal activity

Copper is an essential micronutrient that is necessary for healthy immune function. This requirement is underscored by an increased susceptibility to bacterial infection in copper-deficient animals; however, a molecular understanding of its importance in immune defense is unknown. In this study, we investigated the effect of proinflammatory agents on copper homeostasis in RAW264.7 macrophages. Interferon-gamma was found to increase expression of the high affinity copper importer, CTR1, and stimulate copper uptake. This was accompanied by copper-stimulated trafficking of the ATP7A copper exporter from the Golgi to vesicles that partially overlapped with phagosomal compartments. Silencing of ATP7A expression attenuated bacterial killing, suggesting a role for ATP7A-dependent copper transport in the bactericidal activity of macrophages. Significantly, a copper-sensitive mutant of Escherichia coli lacking the CopA copper-transporting ATPase was hypersensitive to killing by RAW264.7 macrophages, and this phenotype was dependent on ATP7A expression. Collectively, these data suggest that copper-transporting ATPases, CopA and ATP7A, in both bacteria and macrophage are unique determinants of bacteria survival and identify an unexpected role for copper at the host-pathogen interface.

Zinc deficiency increases organ damage and mortality in a murine model of polymicrobial sepsis

OBJECTIVE

Zinc deficiency is common among populations at high risk for sepsis mortality, including elderly, alcoholic, and hospitalized patients. Zinc deficiency causes exaggerated inflammatory responses to endotoxin but has not been evaluated during bacterial sepsis. We hypothesized that subacute zinc deficiency would amplify immune responses and oxidant stress during bacterial sepsis {lsqb;i.e., cecal ligation and puncture (CLP){rsqb; resulting in increased mortality and that acute nutritional repletion of zinc would be beneficial.

DESIGN

Prospective, randomized, controlled animal study.

SETTING

University medical center research laboratory.

SUBJECTS

Adult male C57BL/6 mice.

INTERVENTIONS

Ten-week-old, male, C57BL/6 mice were randomized into three dietary groups: 1) control diet, 2) zinc-deficient diet for 3 weeks, and 3) zinc-deficient diet for 3 weeks followed by oral zinc supplementation for 3 days (n = 35 per diet). Mice were then assigned to receive either CLP or sham operation (n = 15 each per diet). CLP and sham-operated treatment groups were further assigned to a 7-day survival study (n = 10 per treatment per diet) or were evaluated at 24 hours (n = 5 per treatment per diet) for signs of vital organ damage.

MEASUREMENTS AND MAIN RESULTS

Sepsis mortality was significantly increased with zinc deficiency (90% vs. 30% on control diet). Zinc-deficient animals subject to CLP had higher plasma cytokines, more severe organ injury, including increased oxidative tissue damage and cell death, particularly in the lungs and spleen. None of the sham-operated animals died or developed signs of organ damage. Zinc supplementation normalized the inflammatory response, greatly diminished tissue damage, and significantly reduced mortality.

CONCLUSIONS

Subacute zinc deficiency significantly increases systemic inflammation, organ damage, and mortality in a murine polymicrobial sepsis model. Short-term zinc repletion provides significant, but incomplete protection despite normalization of inflammatory and organ damage indices.

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.

Burn-induced oxidative stress is altered by a low zinc status: kinetic study in burned rats fed a low zinc diet

As an initial subdeficient status of zinc, considered as an essential antioxidant trace element, is frequent in burned patients, we aim to assess the effects of low zinc dietary intakes on burn-induced oxidative stress, in an animal model. After 8 weeks of conditioning diets containing 80 ppm (control group) or 10 ppm of zinc (depleted group), Wistar rats were 20% TBSA burned and sampled 1-10 days after injury. Kinetic evolutions of zinc status, plasma oxidative stress parameters, and antioxidant enzymes were also studied in blood and organs. The zinc-depleted diet induced, before injury, a significant decrease in zinc bone level and the increase of oxidative stress markers without stimulation of antioxidant enzyme activity. After burn, more markedly in zinc depleted animals than in controls, zinc levels decreased in plasma and bone, while increasing in liver. The decrease of thiol groups and GSH/GSSG ratio and the depression of GPx activity in liver are also moderately emphasized. Nevertheless, depleted zinc status could not be considered as determining for oxidative damages after burn injury. Further investigations must also be done to enlighten the mechanism of beneficial effects of zinc supplementation reported in burned patients.

Tissue 65Zinc translocation in a rat model of chronic aldosteronism

Zinc, an essential micronutrient, is involved in wound healing. The hypozincemia seen with chronic aldosteronism is associated with enhanced fecal and urinary excretory Zn losses, and its tissue distribution is less certain. This study monitored tissue 65Zn distribution in uninephrectomized rats at weeks 1 and 4 of aldosterone/salt treatment (ALDOST). Plasma and tissue total radionucleotide uptake was determined by calculating its mean radioactivity at 1, 4, 8, 24, and 48 hours after intravenous 65Zn administration and where respective area under the concentration-time curves (AUC) were determined by the linear trapezoidal rule and expressed as a tissue:plasma AUC ratio. Examined tissues included: (1) injured heart and kidney in response to ALDOST and incised skin; (2) noninjured liver, skeletal muscle, and spleen sites of stress-linked Zn uptake; and (3) bone, a major storage and release site when Zn homeostasis is threatened. In comparison with age-matched and gender-matched controls, the following were found with week 1 and 4 ALDOST: (1) reduced plasma 65Zn; (2) an accumulation of 65Zn in heart and kidneys, where a well-known vasculopathy involves intramural vessels, and in incised skin at week 1; (3) an organ-specific increase in tissue 65Zn in liver, in keeping with upregulated metallothionein expression, skeletal muscle, and spleen; and (4) a fall in bone and healed skin Zn at week 4. Thus a wide-ranging disturbance in Zn homeostasis appears during ALDOST to include its translocation from plasma to injured heart, kidneys, and skin and noninjured liver, skeletal muscle, and spleen together with a resorption of stored Zn in bone at week 4. Zinc dyshomeostasis is an integral feature of chronic aldosteronism.

Longitudinal monitoring of selected elements in blood of healthy young children

There are limited data on essential nutrients in the whole blood of young children. As part of a longitudinal study of the impact on young children and the environment from the introduction of an organic Mn compound into unleaded gasoline in Australia, we have measured a suite of elements in whole blood. The children, aged between 6 and 31 months at recruitment, have been monitored at 6-month intervals for up to 5 years. Blood samples were analysed by inductively coupled plasma mass spectrometry for Ca, Mg, Fe, Mn, Cu, Zn and Pb. Mixed model analyses of 665 blood samples using backward elimination showed significant positive relationships between Ca, Mg and Zn and season, variable relationships with time, but no association with gender or traffic exposure. The elements Ca, Mg and Zn showed higher concentrations in summer compared with winter, whereas Fe and Pb showed lower concentrations in summer compared with winter. Concentrations of all elements except Fe showed significant effects over time: Ca, Cu, Mg, Pb and Mn showed decreases over time, whereas Zn showed an increase. The mixed model analyses with the individual elements as the dependent variable showed some interesting relationships and require further follow-up as some of these appear to conflict with pre-existing concepts, although the multi-element data on which these concepts are based are limited. The variance for blood Pb and blood Mn arising from the other elements was small with 0.5% in the case of blood Pb and 3.7% for blood Mn.

Suplementação de antioxidantes: enfoque em queimados

Na queimadura, os radicais livres são produzidos durante a reposição de fluídos, alterando numerosos componentes, como os ácidos nucléicos, os lipídios e as proteínas. Sendo assim, se, por um lado, essa restauração do fluxo sanguíneo é, em geral, necessária para recuperar a função celular normal, por outro lado a reintrodução do sangue oxigenado nos tecidos isquêmicos contribui para uma produção excessiva de radicais livres derivados do oxigênio, exacerbando a lesão mediada pela isquemia. O papel dos neutrófilos ativados na célula após a queimadura também tem recebido atenção especial. A partir do sistema NADPH oxidase os neutrófilos aderidos podem produzir uma explosão de radical superóxido, produzindo um dano tecidual importante. A queimadura, além de aumentar a produção de radicais livres, também é capaz de impedir os mecanismos de defesa antioxidante, submetendo o paciente queimado ao estresse oxidativo, o qual se constitui em fator perpetuante da resposta inflamatória sistêmica, levando à piora progressiva do estado metabólico. Com esses dados, objetiva-se revisar os principais estudos com a suplementação de antioxidantes em pacientes críticos, com ênfase em pacientes queimados, e descrever os possíveis benefícios dessa intervenção.

Trace element supplementation after major burns modulates antioxidant status and clinical course by way of increased tissue trace element concentrations

BACKGROUND

After major burns, patients can develop nutritional deficiencies including trace element (TE) deficiencies. Various complications, such as infections and delayed wound healing, influence the clinical course of such patients.

OBJECTIVES

We aimed to investigate the effects of large, intravenous doses of TE supplements on circulating and cutaneous TE tissue concentrations, on antioxidant status, and on clinical outcome after major burns.

DESIGN

This was a prospective, randomized, placebo-controlled trial in 21 patients aged 35 +/- 11 y (x +/- SD) with burns on 45 +/- 21% of their body surface area. Intravenous copper, selenium, and zinc (TE group) or vehicle (V group) was given with a saline solution for 14-21 d. Blood and urine samples were collected until day 20, and skin biopsy specimens were collected on days 3, 10, and 20.

RESULTS

The age of the patients and the severity of their burns did not differ significantly between the groups. Plasma TE concentrations were significantly higher in the TE group. In burned areas, skin contents of both selenium (P=0.05) and zinc (P=0.04) increased significantly by day 20. Plasma and tissue antioxidant status was improved by supplementation. The number of infections in the first 30 d was significantly lower in the TE group (P=0.015), with a median number of 2 versus 4 infections per patient in the TE and V groups, respectively, as a result of a reduction in pulmonary infections (P=0.03). Wound healing was improved in the TE group, with lower requirements for regrafting (P=0.02).

CONCLUSIONS

TE supplementation was associated with higher circulating plasma and skin tissue contents of selenium and zinc and improved antioxidant status. These changes were associated with improved clinical outcome, including fewer pulmonary infections and better wound healing.

Trace element requirements in critically ill burned patients

Critically ill burned patients are characterized by a strong oxidative stress, an intense inflammatory response, and months-long hypermetabolism, all of which are proportional to the severity of injury. Trace element (TE) deficiencies have repeatedly been described. The clinical course is complicated by organ failures, infections, and delayed wound healing, which can be partly attributed to TE deficiencies. Among critically ill patients, TE deficiencies are the most severe in major burns, who suffer a specific copper deficiency. Plasma TE concentrations are low during any critical illness, as a result of TE losses in biological fluids, low intakes, dilution by fluid resuscitation, and redistribution from plasma to tissues mediated by the inflammatory response. The large exudative losses cause negative TE balances. Intravenous supplementation trials show that early substitution improves recovery, reduces infectious complications (particularly nosocomial pneumonia), normalize thyroid function, normalize skin tissue levels, improve wound healing and shorten hospital stay. Nevertheless, prolonged high dose delivery may be deleterious, as TE have potential for toxicity. In major burns, supplements up to 4 mg of Cu/day, 500 mcg [DOSAGE ERROR CORRECTED] Se/day and 40 mg Zn/day for 3 weeks have been found to be safe and effective. The intravenous route appears the only way to deliver the doses required to achieve antioxidant and clinical effects. Further research is required to determine the optimal combination and doses for different severities of injury.