Bench-to-bedside review: Burn-induced cerebral inflammation--a neglected entity?

Post-traumatic stress disorder in burn patients - A large database analysis

INTRODUCTION

Post-traumatic stress disorder (PTSD) afflicts a significant portion of burn patients. This study aims to analyze the morbidity, prevalence, and treatment of PTSD in the burn population.

METHODS

Using the TriNetX database, we identified burned patients > 18 years of age without (A) or with (B) a PTSD diagnosis. Patients were then stratified by percent of total body surface area (TBSA) burned. Morbidity and mortality was analyzed in each cohort. Prevalence and pharmacologic treatments for PTSD were analyzed from 2002 to 2022.

RESULTS

PTSD incidence increased from 2.4% (n = 2281) in patients with < 10% to 3.1% (n = 542) in 10-30%, 7.4% (n = 285) in 30-59%, and 5.3% (n = 90) in > 60% TBSA burned. In patients with < 60% TBSA burned, PTSD diagnosis increased the risk of depression (p = <0.0003) and anxiety (p = <0.0001). In those with < 30% TBSA burned, PTSD diagnosis also increased risk of insomnia (p = <0.0001) and pruritus (p = 0.0211 for TBSA <10% and 0.0059 for TBSA 10-29%). PTSD diagnosis was associated with a decreased risk of mortality in patients with > 30% TBSA burned (p = 0.0179 for TBSA 30-59% and p = 0.0089 for TBSA >60%). From 2002 to 2022, the prevalence of PTSD in all burn patients was relatively stable between 2.2% and 3.2%. We found an increase in the use of serotonergic agents and prazosin for the treatment of PTSD during this timeframe.

CONCLUSION

PTSD is not uncommon in the burn population, and those with burns and concomitant PTSD have an increased risk of morbidity. Screening and preventative measures to reduce morbidity and early implementation of care in burned patients with PTSD are indicated.

The impact of burn injury on the central nervous system

Burn injuries can be devastating, with life-long impacts including an increased risk of hospitalization for a wide range of secondary morbidities. One area that remains not fully understood is the impact of burn trauma on the central nervous system (CNS). This review will outline the current findings on the physiological impact that burns have on the CNS and how this may contribute to the development of neural comorbidities including mental health conditions. This review highlights the damaging effects caused by burn injuries on the CNS, characterized by changes to metabolism, molecular damage to cells and their organelles, and disturbance to sensory, motor and cognitive functions in the CNS. This damage is likely initiated by the inflammatory response that accompanies burn injury, and it is often long-lasting. Treatments used to relieve the symptoms of damage to the CNS due to burn injury often target inflammatory pathways. However, there are non-invasive treatments for burn patients that target the functional and cognitive damage caused by the burn, including transcranial magnetic stimulation and virtual reality. Future research should focus on understanding the mechanisms that underpin the impact of a burn injury on the CNS, burn severity thresholds required to inflict damage to the CNS, and acute and long-term therapies to ameliorate deleterious CNS changes after a burn.

Mining the potential therapeutic targets for COVID-19 infection in patients with severe burn injuries via bioinformatics analysis

The Coronavirus Disease-19 (COVID-19) pandemic is posing a serious challenge to human health. Burn victims are susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leading to delayed recovery and even profound debilitation. Nevertheless, the molecular mechanisms underlying COVID-19 and severe burn are yet to be elucidated. In our work, the differentially expressed genes (DEGs) were identified from GSE157852 and GSE19743, and the common DEGs between COVID-19 and severe burn were extracted. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), protein-protein interactions (PPI), gene coexpression network, and multifactor regulatory network analysis of hub genes were carried out. A total of 44 common DEGs were found between COVID-19 and severe burn. Functional analyses indicated that the pathways of immune regulation and cytokine response participated collectively in the development of severe burn and progression of COVID-19. Ten significant hub genes were identified, including MERTK, SIRPA, TLR3, ITGB1, DPP4, PTPRC, LY75, IFIT1, IL4R, and CD2. In addition, the gene coexpression network and regulatory network were constructed containing 42 microRNAs (miRNAs) and 2 transcription factors (TFs). Our study showed the shared pathogenic link between COVID-19 and severe burn. The identified common genes and pivotal pathways pave a new road for future mechanistic researches in severe burn injuries complicated with COVID-19.

Use of extracorporeal membrane oxygenation in children with burn injury: Case report and literature review

RATIONALE

Burns are one of the most debilitating injuries in the world and one of the major causes of accidental disability and death among children. Severe burns can result in irreversible brain damage, placing patients at high risk of brain failure and high mortality. Therefore, timely diagnosis and treatment of burn encephalopathy are crucial for improving prognosis. In recent years, extracorporeal membrane oxygenation (ECMO) has been increasingly used to improve the prognosis of patients with burns. Here, we report a case of ECMO treatment in a child with burns and review the relevant literature.

PATIENT CONCERNS

A 7-year-old boy with a modified Baux score of 24 presented with asphyxia, loss of consciousness, refractory hypoxemia, and malignant arrhythmia after smoke inhalation for 1 day. Fiberoptic bronchoscopy revealed a large amount of black carbon-like substances aspirated from the trachea.

DIAGNOSES

Considering that the boy inhaled a large amount of smoke, the clinical manifestation was unclear consciousness, laboratory examination revealed continuous low blood oxygen saturation, and bronchoscopy revealed a large amount of black carbon-like substances in the trachea, thereby leading to the diagnosis of asphyxia, inhalation pneumonia, burn encephalopathy, multiple organ dysfunction syndrome, and malignant arrhythmia. In addition, pulmonary edema and carbon monoxide poisoning are caused by chemical agents, gas fumes, and vapors.

INTERVENTIONS

The boy's blood oxygen saturation and blood circulation remained unstable despite various ventilation methods and medications, thus we decided to use ECMO. After 8 days of ECMO support, the patient was successfully weaned from the machine.

OUTCOMES

Under the application of ECMO, the respiratory and circulatory systems significantly improved. Nevertheless, due to the progressive brain injury caused by burns and the poor prognosis, the parents ceased all treatment and the boy passed away.

LESSONS

This case report demonstrates that brain edema and herniation can arise as phenotypes of burn encephalopathy, which is a challenge to treat in children. Children with confirmed or suspected burn encephalopathy should undergo diagnostic tests completed as soon as possible to confirm the diagnosis. After receiving ECMO treatment, the respiratory and circulatory systems of the burn victims reported significantly improved. Hence, ECMO is a viable alternative for supporting patients with burns.

Pathological changes in the brain after peripheral burns

Brain injuries are common complications in patients with thermal burns and are associated with unpleasant outcomes. In clinical settings, it was once believed that brain injuries were not major pathological processes after burn, at least in part due to the unavailability of specific clinical manifestations. Burn-related brain injuries have been studied for more than a century, but the underlying pathophysiology has not been completely clarified. This article reviews the pathological changes in the brain following peripheral burns at the anatomical, histological, cytological, molecular and cognitive levels. Therapeutic indications based on brain injury as well as future directions for research have been summarized and proposed.

Researches on cognitive sequelae of burn injury: Current status and advances

Burn injury is a devastating disease with high incidence of disability and mortality. The cognitive dysfunctions, such as memory defect, are the main neurological sequelae influencing the life quality of burn-injured patients. The post-burn cognitive dysfunctions are related to the primary peripheral factors and the secondary cerebral inflammation, resulting in the destruction of blood-brain barrier (BBB), as is shown on Computed Tomography (CT) and magnetic resonance imaging examinations. As part of the neurovascular unit, BBB is vital to the nutrition and homeostasis of the central nervous system (CNS) and undergoes myriad alterations after burn injury, causing post-burn cognitive defects. The diagnosis and treatment of cognitive dysfunctions as burn injury sequelae are of great importance. In this review, we address the major manifestations and interventions of post-burn cognitive defects, as well as the mechanisms involved in memory defect, including neuroinflammation, destruction of BBB, and hormone imbalance.

Cutaneous burn injury induces neuroinflammation and reactive astrocyte activation in the hippocampus of aged mice

BACKGROUND

By 2050, one in six people globally will be 65 or older. Confusion and delirium are significant complications after burn injury, especially in the elderly population. The etiology is still unknown, however complications may be driven by pro-inflammatory activation of astrocytes within the hippocampus (HPC) after burn injury. Reduced levels of phosphorylated cyclic-AMP response binding element (pCREB), caused by elevated systemic pro-inflammatory cytokines, could lead to cognitive decline and memory impairment.

METHODS

To examine the effects of remote injury on neuroinflammation in advanced age, young and aged mice were subjected to a 15 % total body surface area scald burn or sham injury, and euthanized after 24 h. Expression of ccl2 and tnfa were measured by qPCR in the whole brain and HPC. Astrocyte activation was measured by immunofluorescence within the HPC. pCREB was measured by immunohistochemistry in the dentate gyrus.

RESULTS

We saw an 80-fold increase in ccl2 and a 30-fold elevation in tnfa after injury in the whole brain of aged mice compared to young groups and aged sham mice (p < 0.05 and p < 0.05, respectively). Additionally, there was a 30-fold increase in ccl2 within isolated HPC of aged injured mice when compared to sham injured animals (p < 0.05). When investigating specific HPC regions, immunofluorescence staining showed a >20 % rise in glial fibrillary acidic protein (GFAP) positive astrocytes within the cornu ammonis 3 (CA3) of aged injured mice when compared to all other groups (p < 0.05). Lastly, we observed a >20 % decrease in pCREB staining by immunohistochemistry in the dentate gyrus of aged mice compared to young regardless of injury (p < 0.05).

CONCLUSIONS

These novel data suggest that remote injury in aged, but not young, mice is associated with neuroinflammation and astrocyte activation within the HPC. These factors, paired with an age related reduction in pCREB, could help explain the increased cognitive decline seen in burn patients of advanced age. To our knowledge, we are the first group to examine the impact of advanced age combined with burn injury on inflammation and astrocyte activation within the brain.

Sepsis-Induced Brain Dysfunction: Pathogenesis, Diagnosis, and Treatment

Dysregulated host response to infection, which cause life-threatening organ dysfunction, was defined as sepsis. Sepsis can cause acute and long-term brain dysfunction, namely, sepsis-associated encephalopathy (SAE) and cognitive impairment. SAE refers to changes in consciousness without direct evidence of central nervous system infection. It is highly prevalent and may cause poor outcomes in sepsis patients. Cognitive impairment seriously affects the life quality of sepsis patients and increases the medical burden. The pathogenesis of sepsis-induced brain dysfunction is mainly characterized by the interaction of systemic inflammation, blood-brain barrier (BBB) dysfunction, neuroinflammation, microcirculation dysfunction, and brain dysfunction. Currently, the diagnosis of sepsis-induced brain dysfunction is based on clinical manifestation of altered consciousness along with neuropathological examination, and the treatment is mainly involves controlling sepsis. Although treatments for sepsis-induced brain dysfunction have been tested in animals, clinical treat sepsis-induced brain dysfunction is still difficult. Therefore, we review the underlying mechanisms of sepsis-induced brain injury, which mainly focus on the influence of systemic inflammation on BBB, neuroinflammation, brain microcirculation, and the brain function, which want to bring new mechanism-based directions for future basic and clinical research aimed at preventing or ameliorating brain dysfunction.

Burn Shock and Resuscitation: Review and State of the Science

Burn shock and acute fluid resuscitation continue to spark intense interest and debate among burn clinicians. Following a major burn injury, fluid resuscitation of burn shock is life-saving, but paradoxically can also be a source of increased morbidity and mortality because of the unintended consequence of systemic edema formation. Considerable research over the past two decades has been devoted to understanding the mechanisms of edema formation, and to develop strategies to curb resuscitation fluids and limit edema development. Recognition of burn endotheliopathy - injury to the endothelium's glycocalyx layer- is one of the most important recent developments in our understanding of burn shock pathophysiology. Newer monitoring approaches and resuscitation endpoints, along with alternative resuscitation strategies to crystalloids alone, such as administration of albumin, or plasma, or high dose ascorbic acid, have had mixed results in limiting fluid creep. Clear demonstration of improvements in outcomes with all of these approaches remains elusive. This comprehensive review article on burn shock and acute resuscitation accompanies the American Burn Association's State of the Science meeting held in New Orleans, LA on November 2-3, 2021 and the Proceedings of that conference published in this journal.

Cerebral dysfunctions caused by sepsis during ageing

Systemic inflammation elicited by sepsis can induce an acute cerebral dysfunction known as sepsis-associated encephalopathy (SAE). Recent evidence suggests that SAE is common but shows a dynamic trajectory over time. Half of all patients with sepsis develop SAE in the intensive care unit, and some survivors present with sustained cognitive impairments for several years after initial sepsis onset. It is not clear why some, but not all, patients develop SAE and also the factors that determine the persistence of SAE. Here, we first summarize the chronic pathology and the dynamic changes in cognitive functions seen after the onset of sepsis. We then outline the cerebral effects of sepsis, such as neuroinflammation, alterations in neuronal synapses and neurovascular changes. We discuss the key factors that might contribute to the development and persistence of SAE in older patients, including premorbid neurodegenerative pathology, side effects of sedatives, renal dysfunction and latent virus reactivation. Finally, we postulate that some of the mechanisms that underpin neuropathology in SAE may also be relevant to delirium and persisting cognitive impairments that are seen in patients with severe COVID-19.

In this Review, Manabe and Heneka examine how the systemic inflammation associated with sepsis can lead to acute cerebral dysfunction known as sepsis-associated encephalopathy (SAE). Moreover, they suggest that some of the mechanisms involved in SAE may be relevant for understanding the cognitive impairments that develop in some patients with COVID-19.

Pseudomonal Meningoencephalitis With Ventriculitis Secondary to Bacteremia in a Burn Patient: A Novel Case

Burn patients with large burn surface area involvement are at increased risk of infection due to the presence of large wounds, multiple surgeries, prolonged intensive care unit admission, and immunosuppression. Pseudomonas aeruginosa is the most commonly isolated organism in this population. Even with frequent infections in the burn population, meningitis and encephalitis are rare, and ventriculitis is exceptional. We report the case of a 66-year-old woman who developed P. aeruginosa bacteremia during her hospital course, causing secondary meningoencephalitis with ventriculitis. She was admitted for partial- and full-thickness burns affecting the neck, chest, abdomen, upper medial arms, and bilateral anteromedial thighs for an estimated 20% total body surface area burn. She met sepsis criteria and broad-spectrum antimicrobial coverage was initiated. Magnetic resonance imaging of the brain, performed for altered mental status, revealed meningitis and ventriculitis. Cerebrospinal fluid analysis demonstrated findings consistent with bacterial meningitis, with cultures positive for P. aeruginosa. Serial neuroimaging with computerized tomography revealed new areas of ischemia concerning for septic emboli. In the presence of altered mental status and fever of unknown origin, workup should remain broad. Even in the presence of another source, it is important to keep an open mind for the rarer intracerebral infection as it requires different management, including urgent evaluation of antibiotic selection and dosing to ensure central nervous system penetration, and neurosurgical evaluation.

Matrine alleviates neurobehavioral alterations via modulation of JNK-mediated caspase-3 and BDNF/VEGF signaling in a mouse model of burn injury

RATIONALE

The c-Jun N-terminal kinase (JNK) pathway and neurotrophic factor dysregulation play a critical role in the pathogenesis of neurobehavioral disorders (anxiety and depression). Targeting the JNK pathway and BDNF/VEGF signaling may signify a new avenue for the treatment of neurobehavioral disorders.

OBJECTIVES

The present study investigated the effect of matrine (Mat) against anxiety- and depressive-like emotional status in an acute mouse model of burn injury and explores its underlying mechanism.

METHODS

In the mouse model of thermal injury, anxiety- and depression-related behaviors were evaluated using the elevated plus-maze test, the light-dark box test, the open-field test, the forced swimming test, and the tail suspension test. The JNK/caspase-3 and BDNF/VEGF proteins were determined by immunohistochemistry. Additionally, proinflammatory cytokine, antioxidant, nitric oxide, and corticosterone levels were also measured.

RESULTS

The results showed that treatment with Mat significantly improves anxiety- and depressive-like behaviors. It remarkably reduced the levels of proinflammatory cytokines, malondialdehyde, and nitric oxide in the hippocampus and prefrontal cortex of a mouse brain. It considerably improved burn-induced alteration in the antioxidant status, corticosterone, and BDNF/VEGF. It also inhibited burn-induced apoptotic signaling by downregulating the expression of JNK/caspase-3. Similarly, it prevented DNA damage and histopathological changes in the dentate gyrus of the hippocampus. Furthermore, molecular docking results showed that Mat possess better binding affinity for JNK/caspase-3 and BDNF/VEGF proteins.

CONCLUSIONS

These findings provide convincing evidence that Mat improves anxiety- and depressive-like emotional status through modulation of JNK-mediated inflammatory, oxidative stress, apoptotic, and BDNF/VEGF signaling in an acute mouse model of burn injury.

Mortality following combined burn and traumatic brain injuries: An analysis of the national trauma data bank of the American College of Surgeons

BACKGROUND

Severe burn and traumatic brain injuries (TBI) lead to significant mortality, and combined burn-TBI injuries may predispose towards even worse outcomes. The purpose of this study was to investigate the mortality of patients with burn, burn with non-TBI trauma, and combined burn/TBI to determine if combined injury portends a worse outcome.

METHODS

We obtained the National Trauma Data Bank from 2007 to 2012, identifying 32,334 patients with burn related injuries, dividing this cohort into three injury types: BURN ONLY, BURN with TRAUMA/NO TBI, and BURN with TBI. For each patient, demographic data was obtained, including age, gender, presence of trauma, TBI, or inhalation injury, burn total body surface area (TBSA), Glasgow Coma Scale, Injury Severity Score, and mortality. Multivariable logistic regression was performed.

RESULTS

Age, gender, and TBSA were similar across the three injury groups, but the incidence of inhalation injury was doubled in the BURN with TRAUMA/NO TBI (15.4 %) and BURN with TBI (15.3 %) groups when compared to the BURN ONLY (7.2 %) group. Mortality differed across injury categories after adjusting for age, TBSA, and inhalation injury. Increased mortality was seen in BURN with TRAUMA/NO TBI versus BURN ONLY (OR = 1.27 [1.06, 1.53]) and was higher when comparing BURN with TBI versus BURN ONLY (OR = 4.22 [2.85, 6.18]). BURN with TBI also had higher mortality when compared to BURN with TRAUMA/NO TBI (OR = 3.33 [2.30, 4.82]). The logs odds of mortality also increased with increasing age, TBSA and presence of inhalation injury.

DISCUSSION

This analysis of the NTDB suggests that mortality following burn-related injuries may be higher when burn injury is combined with TBI when compared to burns with other trauma, even after correcting for age, TBSA, and inhalation injury. Further clinical and laboratory research is needed to validate these findings and better understand how to optimize combined TBI and burn injury treatment.

Challenges in anaesthesia and pain management for burn injuries

Burn-injured patients provide unique challenges to those providing anaesthesia and pain management. This review aims to update both the regular burn anaesthetist and the anaesthetist only occasionally involved with burn patients in emergency settings. It addresses some aspects of care that are perhaps contentious in terms of airway management, fluid resuscitation, transfusion practices and pharmacology. Recognition of pain management failures and the lack of mechanism-specific analgesics are discussed along with the opioid crisis as it relates to burns and nonpharmacological methods in the management of distressed patients.

Modelling traumatic brain injury and posttraumatic epilepsy in rodents

Posttraumatic epilepsy (PTE) is one of the most debilitating and understudied consequences of traumatic brain injury (TBI). It is challenging to study the effects, underlying pathophysiology, biomarkers, and treatment of TBI and PTE purely in human patients for a number of reasons. Rodent models can complement human PTE studies as they allow for the rigorous investigation into the causal relationship between TBI and PTE, the pathophysiological mechanisms of PTE, the validation and implementation of PTE biomarkers, and the assessment of PTE treatments, in a tightly controlled, time- and cost-efficient manner in experimental subjects known to be experiencing epileptogenic processes. This article will review several common rodent models of TBI and/or PTE, including their use in previous studies and discuss their relative strengths, limitations, and avenues for future research to advance our understanding and treatment of PTE.

Correlation between Depression, Posttraumatic Stress Disorder, and Inflammatory Factors in Patients with Severe Burn Injury

We aim to investigate the relation between depression, posttraumatic stress disorder (PTSD), and inflammatory factors in patients with severe burn injury. Psychological assessment was carried out using PTSD checklist (PCL) involving a 17-item self-report questionnaire (PCL-17) and the Hamilton Rating Scale for depression (HAMD-24). The serum IL-1β, IL-6, IL-8, and tumor necrosis factor-α (TNF-α) were determined using enzyme-linked immunosorbent assay. Correlation analysis was performed to analyze the correlation between the factors and scores of PTSD and depression. Compared with the PCL-17 score, HAMD-24 score, and inflammatory factors at month 3, a significant decrease was noticed in the PCL-17 score, HAMD-24 score, and inflammatory factors at months 6 and 9 (P < 0.01). For the HAMD-24 score, significant improvements were noticed in the anxiety/somatization, cognitive disorder, blocking, sleep disorders, and depression at months 3, 6, and 9. The levels of IL-1β, IL-8, and TNF-α were positively correlated with the PCL-17 score (P < 0.05). The levels of IL-1β, IL-6, IL-8, and TNF-α were positively correlated with the HAMD-24 score (P < 0.05). Patients with severe burn injury showed obvious stress alternation displaying specific depression-related characteristics, and inflammation may involve in the pathogenesis of PTSD and depression in burn patients.

Perioperative Research into Memory (PRiMe): Cognitive impairment following a severe burn injury and critical care admission, part 1

INTRODUCTION

An investigation into long-term cognitive impairment and Quality of Life (QoL) after severe burns.

METHODS

A proof of principle, cohort design, prospective, observational clinical study. Patients with severe burns (>15% TBSA) admitted to Burns ICU for invasive ventilation were recruited for psychocognitive assessment with a convenience sample of age and sex-matched controls. Participants completed psychological and QoL questionnaires, the Cogstate^® electronic battery, Hopkins Verbal Learning, Verbal Fluency and Trail making tasks.

RESULTS

15 patients (11M, 4F; 41±14 years; TBSA 38.4%±18.5) and comparators (11M, 4F; 40±13 years) were recruited. Burns patients reported worse QoL (Neuro-QoL Short Form v2, patient 30.1±8.2, control 38.7±3.2, p=0.0004) and cognitive function (patient composite z-score 0.01, IQR -0.11 to 0.33, control 0.13, IQR 0.47-0.73, p=0.02). Compared to estimated premorbid FSIQ, patients dropped an equivalent of 8 IQ points (p=0.002). Cognitive function negatively correlated with burn severity (rBaux score, p=0.04). QoL strongly correlated with depressive symptoms (Rho=-0.67, p=0.009) but not cognitive function.

CONCLUSIONS

Severe burns injuries are associated with a significant, global, cognitive deficit. Patients also report worse QoL, depression and post-traumatic stress. Perceived QoL from cognitive impairment was more closely associated with depression than cognitive impairment.

The role of complement in the acute phase response after burns

Severe burns induce a complex systemic inflammatory response characterized by a typical prolonged acute phase response (APR) that starts approximately 4-8h after-burn and persists for months up to a year after the initial burn trauma. During this APR, acute phase proteins (APPs), including C-reactive protein (CRP) and complement (e.g. C3, C4 and C5) are released in the blood, resulting amongst others, in the recruitment and migration of inflammatory cells. Although the APR is necessary for proper wound healing, a prolonged APR can induce local tissue damage, hamper the healing process and cause negative systemic effects in several organs, including the heart, lungs, kidney and the central nervous system. In this review, we will discuss the role of the APR in burns with a specific focus on complement.

Neurologic complications of acute environmental injuries

Environmental injuries can result in serious neurologic morbidity. This chapter reviews neurologic complications of thermal burns, smoke inhalation, lightning strikes, electric injury, near drowning, decompression illness, as well as heat stroke and accidental hypothermia. Knowing the pathophysiology and clinical presentation of such injuries is essential to proper management of primary and secondary medical complications. This chapter highlights the most frequently encountered neurologic injuries secondary to common environmental hazards, divided into the topics: injuries related to fire, electricity, water, and the extremes of temperature.

Burn injury and long-term nervous system morbidity: a population-based cohort study

OBJECTIVE

To investigate if children and adults who are hospitalised for a burn injury have increased long-term hospital use for nervous system diseases.

DESIGN

A population-based retrospective cohort study using linked administrative health data from the Western Australian Data Linkage System.

PARTICIPANTS

Records of 30 997 persons hospitalised for a first burn injury in Western Australia during the period 1980-2012, and 123 399 persons who were age and gender frequency matched with no injury admissions randomly selected from Western Australia's birth registrations and electoral roll.

MAIN OUTCOME MEASURES

Admission rates and summed length of stay for nervous system diseases. Negative binomial and Cox proportional hazards regression modelling were used to generate incidence rate ratios (IRRs) and HRs with 95% CIs, respectively.

RESULTS

After adjustment for demographic factors and pre-existing health status, the burn injury cohort had 2.20 times (95% CI 1.86 to 2.61) as many nervous system admissions and 3.25 times the number of days in hospital (95% CI: 2.28 to 4.64) than the uninjured cohort. This increase was found for those who had sustained burns during childhood (<15 years: IRR, 95% CI: 1.97, 1.49 to 2.61) and early to mid-adulthood (15-45 years: IRR, 95% CI: 2.70, 2.06 to 3.55) and older adults (≥45 years: IRR, 95% CI: 1.62, 1.33 to 1.97). Significantly elevated first-time postburn admissions were observed for children for 15 years postburn discharge (0-5 years: HR, 95% CI: 1.97, 1.75 to 2.22; 5-15 years: HR, 95% CI: 1.44, 1.28 to 1.63) and for adults 45 years and older at index burn for 5 years postburn only (HR, 95% CI: 1.72, 1.42 to 2.09).

CONCLUSIONS

Burn injury appears to be associated with increased nervous system-related morbidity for many years after burn injury. Further work into the mechanisms and possible treatments to reduce this morbidity are warranted in light of these findings.

Pediatric Burn Resuscitation

Children have unique physiologic, physical, psychological, and social needs compared with adults. Although adhering to the basic tenets of burn resuscitation, resuscitation of the burned child should be modified based on the child's age, physiology, and response to injury. This article outlines the unique characteristics of burned children and describes the fundamental principles of pediatric burn resuscitation in terms of airway, circulatory, neurologic, and cutaneous injury management.

Effects of resveratrol on the treatment of inflammatory response induced by severe burn

The aim of this study was to preliminarily investigate the effects of resveratrol on the treatment of systemic inflammatory response induced by severe burn wounding. Through the simulation experiment in vivo on burned mice and simulative experiment in vitro on mice macrophage respectively, differences of the related pro-inflammatory cytokines and SIRT1 expression levels between the resveratrol-treated group and the untreated control group were detected and analyzed. The results of the simulation experiment in vivo on burned mice manifested that the survival rate of the mice in the resveratrol-treated group was markedly higher than that of controls (p<0.05). Resveratrol could significantly reduce the levels of pro-inflammatory factors TNF-α, IL-1β, and IL-6 in serum (p<0.01) and greatly elevate the expression level of SIRT1 (p<0.01). The results of the simulative experiment in vitro on mice macrophage showed no significant difference in TNF-α, IL-1β, or IL-6 contents among three groups (C, mice macrophage control group; R, resveratrol-treated macrophage group; I, SIRT1-inhibitor-treated macrophage group). Whereas, after lipopolysaccharide (LPS) activation (L group), macrophage TNF-α, IL-1β, and IL-6 levels were significantly increased in L group, dramatically higher than those in L+R group (LPS and resveratrol treatment group) (p<0.01). After adding SITR1 inhibitor, three pro-inflammatory cytokines in L+R+I group all showed significant increases compared with those in L+R group (p<0.01). LPS activated macrophages were able to promote the expression of pro-inflammatory cytokines. By upregulating the expression levels of SIRT1, resveratrol could effectively inhibit the inflammation cascade reaction and increase the survival rate of severe burn with bacterial infections in a large extent.

Sepsis-induced brain dysfunction

Systemic infection is often revealed by or associated with brain dysfunction, which is characterized by alteration of consciousness, ranging from delirium to coma, seizure or focal neurological signs. Its pathophysiology involves an ischemic process, secondary to impairment of cerebral perfusion and its determinants and a neuroinflammatory process that includes endothelial activation, alteration of the blood-brain barrier and passage of neurotoxic mediators. Microcirculatory dysfunction is common to these two processes. This brain dysfunction is associated with increased mortality, morbidity and long-term cognitive disability. Its diagnosis relies essentially on neurological examination that can lead to specific investigations, including electrophysiological testing or neuroimaging. In practice, cerebrospinal fluid analysis is indisputably required when meningitis is suspected. Hepatic, uremic or respiratory encephalopathy, metabolic disturbances, drug overdose, sedative or opioid withdrawal, alcohol withdrawal delirium or Wernicke's encephalopathy are the main differential diagnoses. Currently, treatment consists mainly of controlling sepsis. The effects of insulin therapy and steroids need to be assessed. Various drugs acting on sepsis-induced blood-brain barrier dysfunction, brain oxidative stress and inflammation have been tested in septic animals but not yet in patients.

Surgically induced neuropathic pain: understanding the perioperative process

Nerve damage takes place during surgery. As a consequence, significant numbers (10%-40%) of patients experience chronic neuropathic pain termed surgically induced neuropathic pain (SNPP). The initiating surgery and nerve damage set off a cascade of events that includes both pain and an inflammatory response, resulting in "peripheral and central sensitization," with the latter resulting from repeated barrages of neural activity from nociceptors. In affected patients, these initial events produce chemical, structural, and functional changes in the peripheral and central nervous systems (CNS). The maladaptive changes in damaged nerves lead to peripheral manifestations of the neuropathic state-allodynia, sensory loss, shooting pains, etc, that can manifest long after the effects of the surgical injury have resolved. The CNS manifestations that occur are termed "centralization of pain" and affect sensory, emotional, and other (eg, cognitive) systems as well as contributing to some of the manifestations of the chronic pain syndrome (eg, depression). Currently there are no objective measures of nociception and pain in the perioperative period. As such, intermittent or continuous pain may take place during and after surgery. New technologies including direct measures of specific brain function of nociception and new insights into preoperative evaluation of patients including genetic predisposition, appear to provide initial opportunities for decreasing the burden of SNPP, until treatments with high efficacy and low adverse effects that either prevent or treat pain are discovered.

Open-heart surgery increases cerebrospinal fluid levels of Alzheimer-associated amyloid β

BACKGROUND

Neurocognitive dysfunction occurs frequently after open-heart surgery. It has been suggested that cognitive decline after cardiac surgery with cardiopulmonary bypass (CPB) could be a functional consequence of Alzheimer's disease (AD)-like neuropathological changes. The aim of the present study was to evaluate the cerebrospinal fluid (CSF) levels of amyloid β peptide (Aβ(1-42) ) and soluble fragments of amyloid precursor protein (sAPP) as well as the cerebral inflammatory response to open-heart surgery.

METHODS

Ten patients undergoing aortic valve replacement with CPB were included. CSF was obtained the day before and 24 h after surgery for assessment of CSF levels of Aβ(1-42) α-cleaved sAPP and β-cleaved sAPP (sAPP-β). Furthermore, CSF and serum levels of the inflammatory cytokines: tumour necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and interleukin-8 (IL-8) were also assessed.

RESULTS

Cardiac surgery with CPB increased CSF levels of Aβ(1-42) from 447 ± 92 to 641 ± 83 ng/l (P = 0.011), while CSF levels of sAPP-β decreased from 276 ± 35 to 192 ± 21 ng/ml (P = 0.031). CSF levels of TNF-α increased from ≤ 0.60 to 0.79 ± 0.26 ng/l (P = 0.043), IL-6 from 1.89 ± 0.53 to 22.8 ± 6.9 ng/l (P = 0.003) and IL-8 from 39.8 ± 7.8 to 139 ± 18.3 ng/l (P < 0.001).

CONCLUSIONS

Cardiac surgery with CPB causes a profound cerebral inflammatory response, which was accompanied by increased post-operative CSF levels of the AD biomarker Aβ(1-42) . We hypothesize that these changes may be relevant to Alzheimer-associated amyloid build-up in the brain and cognitive dysfunction after cardiac surgery with CPB.

Burn injury induces gelsolin expression and cleavage in the brain of mice

Gelsolin is an actin filament-severing and capping protein, affecting cellular motility, adhesiveness and apoptosis. Whether it is expressed in the brain of burned mice has not yet been characterized. Mice were subjected to a 15% total body surface area scald injury. Neuropathology was examined by hematoxylin and eosin staining. Cerebral gelsolin mRNA, distribution and cleavage were demonstrated by quantitative polymerase chain reaction (QPCR), immunohistochemistry and Western blot, respectively. Cysteinyl aspartate-specific protease (caspase)-3-positive cells and activity were also measured. Burn injury could induce pathological alterations in the brain including leukocyte infiltration, necrosis, microabscess and gliosis. Compared with sham-injured mice, gelsolin mRNA was up-regulated at 8h post-burn (pb) in a transient manner in the cortex and striatum of burned mice, while it remained at higher levels in the hippocampus up to 72 hpb. Of interest, gelsolin was further cleaved into 42 and 48 kDa (kilo Dalton) fragments as illustrated in the hippocampus at 24 hpb, and was widely expressed in the brain by activated monocyte/macrophages, astrocytes and damaged neurons. In the meantime, caspase-3-positive cells were noted in the striatum of burned mice and its activity peaked at 24 hpb. To clarify inflammation-induced gelsolin expression and cleavage in the brain, rat pheochromocytoma cells were exposed to lipopolysaccharide to show increased gelsolin expression and caspase-3-dependent cleavage. The results suggest that burn-induced cerebral gelsolin expression would be involved in the activation of both the monocytes and astroglial cells, thereby playing a crucial role in the subsequent inflammation-induced neural apoptosis following burn injury.

Treatment with gelsolin reduces brain inflammation and apoptotic signaling in mice following thermal injury

Background

Burn survivors develop long-term cognitive impairment with increased inflammation and apoptosis in the brain. Gelsolin, an actin-binding protein with capping and severing activities, plays a crucial role in the septic response. We investigated if gelsolin infusion could attenuate neural damage in burned mice.

Methods

Mice with 15% total body surface area burns were injected intravenously with bovine serum albumin as placebo (2 mg/kg), or with low (2 mg/kg) or high doses (20 mg/kg) of gelsolin. Samples were harvested at 8, 24, 48 and 72 hours postburn. The immune function of splenic T cells was analyzed. Cerebral pathology was examined by hematoxylin/eosin staining, while activated glial cells and infiltrating leukocytes were detected by immunohistochemistry. Cerebral cytokine mRNAs were further assessed by quantitative real-time PCR, while apoptosis was evaluated by caspase-3. Neural damage was determined using enzyme-linked immunosorbent assay of neuron-specific enolase (NSE) and soluble protein-100 (S-100). Finally, cerebral phospho-ERK expression was measured by western blot.

Results

Gelsolin significantly improved the outcomes of mice following major burns in a dose-dependent manner. The survival rate was improved by high dose gelsolin treatment compared with the placebo group (56.67% vs. 30%). Although there was no significant improvement in outcome in mice receiving low dose gelsolin (30%), survival time was prolonged against the placebo control (43.1 ± 4.5 h vs. 35.5 ± 5.0 h; P < 0.05). Burn-induced T cell suppression was greatly alleviated by high dose gelsolin treatment. Concurrently, cerebral abnormalities were greatly ameliorated as shown by reduced NSE and S-100 content of brain, decreased cytokine mRNA expressions, suppressed microglial activation, and enhanced infiltration of CD11b+ and CD45+ cells into the brain. Furthermore, the elevated caspase-3 activity seen following burn injury was remarkably reduced by high dose gelsolin treatment along with down-regulation of phospho-ERK expression.

Conclusion

Exogenous gelsolin infusion improves survival of mice following major burn injury by partially attenuating inflammation and apoptosis in brain, and by enhancing peripheral T lymphocyte function as well. These data suggest a novel and effective strategy to combat excessive neuroinflammation and to preserve cognition in the setting of major burns.

Elevated serum ubiquitin carboxy-terminal hydrolase L1 is associated with abnormal blood-brain barrier function after traumatic brain injury

Serum S100B elevations accurately reflect blood-brain barrier (BBB) damage. Because S100B is also present in peripheral tissues, release of this protein may not be specific to central nervous system (CNS) injury. Ubiquitin C-terminal hydrolase 1 (UCHL1), and phosphorylated neurofilament heavy chain (pNF-H) are found exclusively in neurons, but their relationship to BBB dysfunction has not been determined. The objective of this study was to determine the accuracy of serum UCHL1 and pNF-H as measures of BBB integrity after traumatic brain injury (TBI), to and compare them to S100B. We performed a prospective study of 16 patients with moderate to severe TBI (Glasgow Coma Scale [GCS] score ≤12) and 6 patients with non-traumatic headache who had cerebrospinal fluid (CSF) collected by ventriculostomy or lumbar puncture (LP). Serum and CSF were collected at the time of LP for headache patients and at 12, 24, and 48 h after injury for TBI patients. BBB function was determined by calculating albumin quotients (Q(A)), where Q(A)=[albumin(CSF)]/[albumin(serum)]. S100B, UCHL1, and pNF-H were measured by enzyme-linked immunosorbent assay (ELISA). Pearson's correlation coefficient and area under the receiver operator characteristic (ROC) curve were used to determine relationships between serum markers and Q(A). At 12 hours after TBI, a significant relationship was found between Q(A) and serum UCHL1 concentrations (AUC=0.76; 95% CI 0.55,1.00), and between Q(A) and serum S100B concentrations (AUC=0.794; 95% CI 0.57,1.02). There was no significant relationship found between these markers and Q(A) at other time points, or between pNF-H and Q(A) at any time point. We conclude that serum concentrations of UCHL1 are associated with abnormal BBB status 12 h after moderate to severe TBI. This relationship is similar to that observed between serum S100B and Q(A,) despite the fact that S100B may be released from peripheral tissues after multi-trauma. We conclude that peripheral release of S100B after multi-trauma is probably negligible and that UCHL1 may have some utility to monitor BBB disruption following TBI.