Postinjury multiple organ failure

Extracellular DNA and histones: double-edged swords in immunothrombosis

The existence of extracellular DNA in human plasma, also known as cell-free DNA (cfDNA), was first described in the 1940s. In recent years, there has been a resurgence of interest in the functional significance of cfDNA, particularly in the context of neutrophil extracellular traps (NETs). cfDNA and histones are key components of NETs that aid in the host response to infection and inflammation. However, cfDNA and histones may also exert harmful effects by triggering coagulation, inflammation, and cell death and by impairing fibrinolysis. In this article, we will review the pathologic nature of cfDNA and histones in macrovascular and microvascular thrombosis, including venous thromboembolism, cancer, sepsis, and trauma. We will also discuss the prognostic value of cfDNA and histones in these disease states. Understanding the molecular and cellular pathways regulated by cfDNA and histones may provide novel insights to prevent pathological thrombus formation and vascular occlusion.

MitoQ modulates oxidative stress and decreases inflammation following hemorrhage

BACKGROUND

Oxidative stress associated with hemorrhagic shock and reperfusion (HSR) results in the production of superoxide radicals and other reactive oxygen species, leading to cell damage and multiple-organ dysfunction. We sought to determine if MitoQ, a mitochondria-targeted antioxidant, reduces morbidity in a rat model of HSR by limiting oxidative stress.

METHODS

HSR was achieved in male rats by arterial blood withdrawal to a mean arterial pressure of 25 ± 2 mm Hg for 1 hour before resuscitation. MitoQ (5 mg/kg), TPP (triphenylphosphonium, 5 mg/kg) or saline (0.9% vol./vol.) was administered intravenously 30 minutes before resuscitation, followed by an intraperitoneal administration (MitoQ, 20 mg/kg) immediately after resuscitation (n = 5 per group). Morbidity was assessed based on cumulative markers of animal distress (0-10 scale). Rats were sacrificed 2 hours after procedure completion, and liver tissue was collected and processed for histology or assayed for lipid peroxidation (thiobarbituric acid reactive substance [TBARS]) or endogenous antioxidant (catalase, glutathione peroxidase [GPx], and superoxide dismutase) activity.

RESULTS

HSR significantly increased morbidity as well as TBARS and catalase activities versus sham. Conversely, no difference in GPx or superoxide dismutase activity was measured between sham, HSR, and TPP, MitoQ administration reduced morbidity versus HSR (5.8 ± 0.3 vs. 7.6 ± 0.3; p < 0.05), while TPP administration significantly reduced hepatic necrosis versus both HSR and HSR-MitoQ (1.2 ± 0.1 vs. 2.0 ± 0.2 vs. 1.9 ± 0.2; p < 0.05, n = 5). Analysis of oxidative stress demonstrated increased TBARS and GPx in HSR-MitoQ versus sham (12.0 ± 1.1 μM vs. 6.2 ± 0.5 μM and 37.9 ± 3.0 μmol/min/mL vs. 22.9 ± 2.7 μmol/min/mL, TBARS and GPx, respectively, n = 5; p < 0.05). Conversely, catalase activity in HSR-MitoQ was reduced versus HSR (1.96 ± 1.17 mol/min/mL vs. 2.58 ± 1.81 mol/min/mL; n = 5; p < 0.05). Finally, MitoQ treatment decreased tumor necrosis factor α (0.66 ± 0.07 pg/mL vs. 0.92 ± 0.08 pg/mL) and interleukin 6 (7.3 ± 0.8 pg/mL vs. 11 ± 0.9 pg/mL) versus HSR as did TPP alone (0.58 ± 0.05 pg/mL vs. 0.92 ± 0.08 pg/mL; 6.7 ± 0.6 pg/mL vs. 11 ± 0.9 pg/mL; n = 5; p < 0.05).

CONCLUSION

Our data demonstrate that MitoQ treatment following hemorrhage significantly limits morbidity and decreases hepatic tumor necrosis factor α and interleukin 6. In addition, MitoQ differentially modulates oxidative stress and hepatic antioxidant activity.

The Role of Damage-Associated Molecular Patterns (DAMPs) in Human Diseases: Part II: DAMPs as diagnostics, prognostics and therapeutics in clinical medicine

This article is the second part of a review that addresses the role of damage-associated molecular patterns (DAMPs) in human diseases by presenting examples of traumatic (systemic inflammatory response syndrome), cardiovascular (myocardial infarction), metabolic (type 2 diabetes mellitus), neurodegenerative (Alzheimer's disease), malignant and infectious diseases. Various DAMPs are involved in the pathogenesis of all these diseases as they activate innate immune machineries including the unfolded protein response and inflammasomes. These subsequently promote sterile autoinflammation accompanied, at least in part, by subsequent adaptive autoimmune processes. This review article discusses the future role of DAMPs in routine practical medicine by highlighting the possibility of harnessing and deploying DAMPs either as biomarkers for the appropriate diagnosis and prognosis of diseases, as therapeutics in the treatment of tumours or as vaccine adjuncts for the prophylaxis of infections. In addition, this article examines the potential for developing strategies aimed at mitigating DAMPs-mediated hyperinflammatory responses, such as those seen in systemic inflammatory response syndrome associated with multiple organ failure.

Clinical associations of host genetic variations in the genes of cytokines in critically ill patients

Host genetic variations may influence a changing profile of biochemical markers and outcome in patients with trauma/injury. The objective of this study was to assess clinical associations of single nucleotide polymorphisms (SNPs) in the genes of cytokines in critically ill patients. A total of 430 patients were genotyped for SNPs in the genes of pro- (IL1B, IL6, IL8) and anti-inflammatory (IL4, IL10, IL13) cytokines. The main end-points were sepsis, mortality and adult respiratory distress syndrome (ARDS). We evaluated the dynamic levels of bilirubin, blood urea nitrogen, creatine kinase, creatinine and lactate dehydrogenase in five points of measurements (between 1 and 14 days after admission) and correlated them with SNPs. High-producing alleles of proinflammatory cytokines protected patients against sepsis (IL1B -511A and IL8 -251A) and mortality (IL1B -511A). High-producing alleles of anti-inflammatory cytokines IL4 -589T and IL13 431A (144Gln) were less frequent in ARDS patients. The carriers of IL6 -174C/C genotypes were prone to the increased levels of biochemical markers and acute kidney and liver insufficiency. Genotype-dependent differences in the levels of biochemical indicators gradually increased to a maximal value on the 14th day after admission. These findings suggest that genetic variability in pro- and anti-inflammatory cytokines may contribute to different clinical phenotypes in patients at high risk of critical illness.

Basal functional status predicts functional recovery in critically ill patients with multiple-organ failure

PURPOSE

We aimed to investigate the effect of baseline demographic, clinical, and functional characteristics of intensive care unit (ICU) patients with multiple-organ failure (MOF) on their functional recovery at 6 and 12 months posthospitalization.

MATERIALS AND METHODS

A total of 545 consecutively admitted adult patients with MOF during on admission were included in the study. Patients' functional status was prospectively assessed and compared with the baseline status and at 6 and 12 months postdischarge, using the Modified Rankin Scale and the Glasgow Outcome Scale Extended. Severity of disease on admission was assessed using the Acute Physiology and Chronic Health Evaluation II and the Simplified Acute Physiology Score II.

RESULTS

A total of 266 patients were followed up. Functional status among MOF survivors improved between the 6th and 12th month postdischarge from the ICU. Higher functional status before admission, lower severity scores on admission, and younger age positively affected the improvement in functional status after ICU discharge.

CONCLUSIONS

The level of functional status befre ICU admission should be considered not only in research studies looking a long-term outcomes from ICU but also in the clinical care planning of critically ill patients during and after their ICU admission.

The impact of surgical timing and intervention on outcome in traumatized dogs and cats

OBJECTIVE

To review the relevant human and veterinary literature regarding the timing of surgical intervention for trauma patients and the impact on outcome.

DATA SOURCES

Original research, clinical studies, and review articles with no date restrictions from both human and veterinary literature.

HUMAN DATA SYNTHESIS

Despite extensive research into the ideal timing of surgical intervention for human trauma victims, debate is ongoing and views are still evolving. Prior to the 1970s, the standard of care consisted of delayed surgical treatment, as these patients were considered too ill to undergo surgery. Beginning in the 1970s, and continuing for nearly 2 decades, early definitive surgical treatment was recommended. The most recent evolution of human trauma management incorporates the concept of damage control surgery, which acknowledges the importance of early skeletal stabilization or laparotomy for reducing morbidity while attempting to avoid complications such as acute respiratory distress syndrome or multiple organ dysfunction syndrome.

VETERINARY DATA SYNTHESIS

Despite a relatively large amount of literature available regarding veterinary trauma, no evidence exists to provide the clinician guidance as to the ideal timing of surgery for trauma patients. With the exception of diaphragmatic hernia, no studies were identified that attempted to evaluate this variable.

CONCLUSIONS

Veterinary-specific studies are needed to evaluate the impact of surgical timing on outcome following trauma. The information that can be obtained from studies in this area can improve veterinary trauma care and may be used as models for human trauma care through translational applications.

Comparison of Injury Epidemiology Between the Wenchuan and Lushan Earthquakes in Sichuan, China

Objective

We aimed to compare injury characteristics and the timing of admissions and surgeries in the Wenchuan earthquake in 2008 and the Lushan earthquake in 2013.

Methods

We retrospectively compared the admission and operating times and injury profiles of patients admitted to our medical center during both earthquakes. We also explored the relationship between seismic intensity and injury type.

Results

The time from earthquake onset to the peak in patient admissions and surgeries differed between the 2 earthquakes. In the Wenchuan earthquake, injuries due to being struck by objects or being buried were more frequent than other types of injuries, and more patients suffered injuries of the extremities than thoracic injuries or brain trauma. In the Lushan earthquake, falls were the most common injury, and more patients suffered thoracic trauma or brain injuries. The types of injury seemed to vary with seismic intensity, whereas the anatomical location of the injury did not.

Conclusions

Greater seismic intensity of an earthquake is associated with longer delay between the event and the peak in patient admissions and surgeries, higher frequencies of injuries due to being struck or buried, and lower frequencies of injuries due to falls and injuries to the chest and brain. These insights may prove useful for planning rescue interventions in trauma centers near the epicenter. (Disaster Med Public Health Preparedness. 2014;8:541-547)

Tumor necrosis factor-α-induced microvascular endothelial cell hyperpermeability: role of intrinsic apoptotic signaling

Tumor necrosis factor-α (TNF-α), a pro-apoptotic cytokine, is involved in vascular hyperpermeability, tissue edema, and inflammation. We hypothesized that TNF-α induces microvascular hyperpermeability through the mitochondria-mediated intrinsic apoptotic signaling pathway. Rat lung microvascular endothelial cells grown on Transwell inserts, chamber slides, or dishes were treated with recombinant TNF-α (10 ng/ml) in the presence or absence of a caspase-3 inhibitor, Z-DEVD-FMK (100 μM). Fluorescein isothiocyanate (FITC)-albumin (5 mg/ml) was used as a marker of monolayer permeability. Mitochondrial reactive oxygen species (ROS) was determined using dihydrorhodamine 123 and mitochondrial transmembrane potential using JC-1. The adherens junction integrity and actin cytoskeletal organization were studied using β-catenin immunofluorescence and rhodamine phalloidin, respectively. Caspase-3 activity was measured fluorometrically. The pretreatment with Z-DEVD-FMK (100 μM) attenuated TNF-α-induced (10 ng/ml) disruption of the adherens junctions, actin stress fiber formation, increased caspase-3 activity, and monolayer hyperpermeability (p < 0.05). TNF-α (10 ng/ml) treatment resulted in increased mitochondrial ROS formation and decreased mitochondrial transmembrane potential. Intrinsic apoptotic signaling-mediated caspase-3 activation plays an important role in regulating TNF-α-induced endothelial cell hyperpermeability.

The role of intrinsic apoptotic signaling in hemorrhagic shock-induced microvascular endothelial cell barrier dysfunction

Hemorrhagic shock leads to endothelial cell barrier dysfunction resulting in microvascular hyperpermeability. Hemorrhagic shock-induced microvascular hyperpermeability is associated with worse clinical outcomes in patients with traumatic injuries. The results from our laboratory have illustrated a possible pathophysiological mechanism showing involvement of mitochondria-mediated "intrinsic" apoptotic signaling in regulating hemorrhagic shock-induced microvascular hyperpermeability. Hemorrhagic shock results in overexpression of Bcl-2 family of pro-apoptotic protein, BAK, in the microvascular endothelial cells. The increase in BAK initiates "intrinsic" apoptotic signaling cascade with the release of mitochondrial cytochrome c in the cytoplasm and activation of downstream effector caspase-3, leading to loss of endothelial cell barrier integrity. Thus, this review article offers a brief overview of important findings from our past and present research work along with new leads for future research. The summary of our research work will provide information leading to different avenues in developing novel strategies against microvascular hyperpermeability following hemorrhagic shock.

Hypertonic HBOC-201 decreases neutrophil activation after hemorrhagic shock

OBJECTIVE

To evaluate neutrophil activation after exposure to standard HBC-201 (suspended in lactate Ringer's solution) versus HBOC-201 suspended in hypertonic 7.5% saline solution.

METHODS

We use plasma and tissue obtained from pigs subjected to controlled hemorrhagic shock and an ex vivo model of stimulated human whole blood. The pigs were resuscitated with the following (n = 8 per group) standard HBOC-201, or hypertonic HBOC-201. We used HTS 7.5%, Ringer's lactate as control resuscitation. Human blood was stimulated with same fluids. We measured the following neutrophil markers; IL-8, H2O2 in pig plasma, MPO in pig tissue, and H2O2, IL-8, and CD11b/CD18 in human whole blood.

RESULTS

H2O2 and IL-8 as well as tissue MPO were significantly decreased in pigs resuscitated with HT-HBOC-201 and HT 7.5%. Ex vivo experiments blood diluted with HTS and HT-HBOC-201 revealed lower expression of CD11b/CD18, H2O2, and IL-8. Blood diluted with HBOC-201 had a higher CD11b/CD18 expression than blood diluted with LR solution.

CONCLUSION

Our in vivo and ex vivo experiments indicate that HBOC-201 suspended in hypertonic 7.5% saline solution is associated with significantly less neutrophil activation when compared to standard HBOC-201 suspended in lactate Ringer's solution.

Neutrophil oxidative burst capacity for peri-operative immune monitoring in trauma patients

BACKGROUND

Post injury immune dysfunction can result in serious complications. Measurement of biomarkers may guide the optimal timing of surgery in clinically borderline patients and therefore prevent complications.

AIM

peri-operative measurement of neutrophil oxidative burst capacity as an indicator of the immune response to major orthopaedic surgical procedures.

METHODS

Prospective cohort study of trauma patients aged ≥16 yrs with pelvic, acetabular, femoral shaft or tibial shaft fractures requiring surgical intervention. Blood samples were taken immediately pre-op and at 30 min, 7, 24 and 72-9 6 h post-operatively. Neutrophil oxidative burst capacity was measured both with and without stimulation by formyl-methionyl-leucyl-phenylalanine (fMLP, a chemotactic factor). Clinical outcomes measured were mortality, length of stay, MOF, pneumonia, acute respiratory distress syndrome (ARDS) and sepsis.

RESULTS

100 consecutive orthopaedic trauma patients were enrolled over a 16 month period. 78% were male, with a mean age of 42 ± 18 years and an average ISS of 19 ± 13. Neutrophil oxidative burst capacity was significantly elevated at 7 h (p = 0.006) and 24 h (p = 0.022) post operatively. Patients who developed infective complications (pneumonia and sepsis) had higher levels of oxidative burst capacity pre-operatively (pneumonia: 1.52 ± 0.93 v 0.99 ± 0.66 p = 0.032, sepsis: 1.39 ± 0.86 v 0.97 ± 0.56 p = 0.024) and at 24 h post op (pneumonia: 2.72 ± 2.38 v 1.12 ± 0.63 p = < 0.001, sepsis: 2.16 ± 2.09 v 1.10 ± 0.54 p = < 0.001). When analysed by operation type, no statistical difference was seen between major and minor operations. No correlation was found between length of stay, length of ICU stay, ISS or age and neutrophil oxidative burst capacity at any time point.

CONCLUSIONS

Neutrophil oxidative burst capacity response to orthopaedic trauma surgery is associated with the infective post injury complications. There was no correlation between magnitude of injury or operation and oxidative burst capacity. These results are promising for the development of tools for prediction of post-operative complications and guidance for optimal timing for surgical intervention.

A novel trauma model: naturally occurring canine trauma

In human trauma patients, most deaths result from hemorrhage and brain injury, whereas late deaths, although rare, are the result of multiple organ failure and sepsis. A variety of experimental animal models have been developed to investigate the pathophysiology of traumatic injury and evaluate novel interventions. Similar to other experimental models, these trauma models cannot recapitulate conditions of naturally occurring trauma, and therefore therapeutic interventions based on these models are often ineffective. Pet dogs with naturally occurring traumatic injury represent a promising translational model for human trauma that could be used to assess novel therapies. The purpose of this article was to review the naturally occurring canine trauma literature to highlight the similarities between canine and human trauma. The American College of Veterinary Emergency and Critical Care Veterinary Committee on Trauma has initiated the establishment of a national network of veterinary trauma centers to enhance uniform delivery of care to canine trauma patients. In addition, the Spontaneous Trauma in Animals Team, a multidisciplinary, multicenter group of researchers has created a clinical research infrastructure for carrying out large-scale clinical trials in canine trauma patients. Moving forward, these national resources can be utilized to facilitate multicenter prospective studies of canine trauma to evaluate therapies and interventions that have shown promise in experimental animal models, thus closing the critical gap in the translation of knowledge from experimental models to humans and increasing the likelihood of success in phases 1 and 2 human clinical trials.

Mitochondrial DNA neutrophil extracellular traps are formed after trauma and subsequent surgery

INTRODUCTION

Neutrophil extracellular traps (NETs) have not been demonstrated after trauma and subsequent surgery. Neutrophil extracellular traps are formed from pure mitochondrial DNA (mtDNA) under certain conditions, which is potently proinflammatory. We hypothesized that injury and orthopedic trauma surgery would induce NET production with mtDNA as a structural component.

METHODS

Neutrophils were isolated 8 trauma patients requiring orthopedic surgery postinjury and up to 5 days postoperatively. Four healthy volunteers provided positive and negative controls. Total hip replacement patients acted as an uninjured surgical control group. Neutrophil extracellular traps were visualized with DNA (Hoechst 33342TM/Sytox Green/MitoSox/MitoTracker) stains using live cell fluorescence microscopy with downstream quantitative polymerase chain reaction analysis of DNA composition.

RESULTS

Neutrophil extracellular traps were present after injury in all 8 trauma patients. They persisted for 5 days postoperatively. Delayed surgery resulted in NET resolution, but they reformed postoperatively. Total hip replacement patients developed NETs postoperatively, which resolved by day 5. Quantitative polymerase chain reaction analysis of NET-DNA composition revealed that NETs formed after injury and surgery were made of mtDNA with no detectable nuclear DNA component.

CONCLUSIONS

Neutrophil extracellular traps formed after major trauma and subsequent surgery contain mtDNA and represent a novel marker of heightened innate immune activation. They could be considered when timing surgery after trauma to prevent systemic NET-induced inflammatory complications.

The Cost of Inappropriate Care at the End of life: Implications for an Aging Population

Elderly patients patients (older than 65 years) account for only 11% of the US population yet they account for 34% of health care expenditure. The disproportionate usage of health care costs by elderly patients is in striking contrast with that of other Western Nations. It is likely that these differences are largely due to variances in hospitalization and the use of high technology health care resources at the end of life. The United States has 8 times as many intensive care unit (ICU) beds per capita when compared to other Western Nations. In the United States, elderly patients currently account for 42% to 52% of ICU admissions and for almost 60% of all ICU days. A disproportionate number of these ICU days are spent by elderly patients before their death. In many instances, aggressive life supportive measures serve only to prolong the patient's death. Such treatment inflicts pain and suffering on the patient (with little prospects of gain) and incurs enormous financial costs to the health care system. We present the case of an 86-year-old female who spent almost 3 months in our ICU prior to her death. The fully allocated hospital costs for this patient were estimated to be US$254 945 (US$5100/d). With the increasing age of the population and the projected increased demand for ICU beds, we review the benefits and burdens of admitting elderly patients to the ICU.

Systemic inflammatory response syndrome in patients with spinal cord injury: does its presence at admission affect patient outcomes? Clinical article

OBJECT

The object in this study was to determine whether the presence of systemic inflammatory response syndrome (SIRS) in patients with traumatic spinal cord injury (SCI) on admission is related to subsequent clinical outcome in terms of length of stay (LOS), complications, and mortality.

METHODS

The authors retrospectively reviewed the charts of 193 patients with acute traumatic SCI who had been hospitalized at their institution between 2006 and 2012. Patients were excluded from analysis if they had insufficient SIRS data, a cauda equina injury, a previous SCI, a preexisting neurological condition, or a condition on admission that prevented appropriate neurological assessment. Complications were counted only once per patient and were considered minor if they were severe enough to warrant treatment and major if they were life threatening. Demographics, injury characteristics, and outcomes were compared between individuals who had 2 or more SIRS criteria (SIRS+) and those who had 0 or 1 SIRS criterion (SIRS-) at admission. Multivariate logistic regression (enter method) was used to determine the relative contribution of SIRS+ at admission in predicting the outcomes of mortality, LOS in the intensive care unit (ICU), hospital LOS, and at least one major complication during the acute hospitalization. The American Spinal Injury Association Impairment Scale grade and patient age were included as covariates.

RESULTS

Ninety-three patients were eligible for analysis. At admission 47.3% of patients had 2 or more SIRS criteria. The SIRS+ patients had higher Injury Severity Scores (24.3 ±10.6 vs. 30.2 ±11.3) and a higher frequency of both at least one major complication during acute hospitalization (26.5% vs. 50.0%) and a fracture-dislocation pattern of injury (26.5% vs. 59.1%) than the SIRS- patients (p < 0.05 for each comparison). The SIRS+ patients had a longer median hospital stay (14 vs 18 days) and longer median ICU stay (0 vs. 5 days). However, mortality was not different between the groups. Having SIRS on admission predicted an ICU LOS > 10 days, hospital LOS > 25 days, and at least one complication during the acute hospitalization.

CONCLUSIONS

A protocol to identify SCI patients with SIRS at admission may be beneficial with respect to preventing adverse outcomes and decreasing hospital costs.

Epidemiology and risk factors of multiple-organ failure after multiple trauma: an analysis of 31,154 patients from the TraumaRegister DGU

BACKGROUND

In the severely injured who survive the early posttraumatic phase, multiple-organ failure (MOF) is the main cause of morbidity and mortality. An enhanced prediction of MOF might influence individual monitoring and therapy of severely injured patients.

METHODS

We performed a retrospective analysis of a nationwide prospective database, the TraumaRegister DGU of the German Trauma Society. Patients with complete data sets (2002-2011) and a relevant trauma load (Injury Severity Score [ISS] ≥ 16), who were admitted to an intensive care unit, were included.

RESULTS

Of a total of 31,154 patients enclosed in this study, 10,201 (32.7%) developed an MOF according to the Sequential Organ Failure Assessment score. During the study period, mortality of all patients decreased from 18.1% in 2002 to 15.3% in 2011 (p < 0.001). Meanwhile, MOF occurred significantly more often (24.6% in 2002 vs. 31.5% in 2011, p < 0.001), but mortality of MOF patients decreased (42.6% vs. 33.3%, p < 0.001). MOF patients who died survived 2 days less (11 days in 2002 vs. 8.9 days in 2011, p < 0.001). Independent risk factors for the development of MOF following severe trauma were age, ISS, head Abbreviated Injury Scale (AIS) score of 3 or higher, thoracic AIS score of 3 or higher, male sex, Glasgow Coma Scale (GCS) score of 8 or less, mass transfusion, base excess of less than -3, systolic blood pressure less than 90 mm Hg at admission, and coagulopathy.

CONCLUSION

Over one decade, we observed an ongoing decrease of mortality after multiple trauma, accompanied by decreasing mortality in the subgroup with MOF. However, incidence of MOF in the severely injured increased significantly. Thus, MOF after multiple trauma remains a challenge in intensive care. The risk factors from multivariate analysis could be instrumental in anticipating the early development of MOF. Furthermore, a reliable prediction model might be supportive for patient enrolment in trauma studies, in which MOF marks the primary end point.

LEVEL OF EVIDENCE

Epidemiologic study, level III.

The burden of infection in severely injured trauma patients and the relationship with admission shock severity

BACKGROUND

Infection following severe injury is common and has a major impact on patient outcomes. The relationship between patient, injury, and physiologic characteristics with subsequent infections is not clearly defined. The objective of this study was to characterize the drivers and burden of all-cause infection in critical care trauma patients.

METHODS

A prospective cohort study of severely injured adult patients admitted to critical care was conducted. Data were collected prospectively on patient and injury characteristics, baseline physiology, coagulation profiles, and blood product use. Patients were followed up daily for infectious episodes and other adverse outcomes while in the hospital.

RESULTS

Three hundred patients (Injury Severity Score [ISS] >15) were recruited. In 48 hours or less, 29 patients (10%) died, leaving a cohort of 271. One hundred forty-one patients (52%) developed at least one infection. Three hundred four infections were diagnosed overall. Infection and noninfection groups were matched for age, sex, mechanism, and ISS. Infection rates were greater with any degree of admission shock and threefold higher in the most severely shocked cohort (p < 0.01). In multivariate analysis, base deficit (odds ratio [OR], 1.78, 95% confidence interval [CI], 1.48-1.94; p < 0.001) and lactate (OR, 1.36; 95% CI, 1.10-1.69; p = 0.05) were independently associated with the development of infection. Outcomes were significantly worse for the patients with infection. In multivariate logistic regression, infection was the only factor independently associated with multiple-organ failure (p < 0.001; OR, 15.4; 95% CI, 8.2-28.9; r = 0.402), ventilator-free days (p < 0.001; β, -4.48; 95% CI, -6.7 to -2.1; r = 0.245), critical care length of stay (p < 0.001; β, 13.2; 95% CI, 10.0-16.4; r = 0.466), and hospital length of stay (p < 0.001; β, 31.1; 95% CI, 24.0-38.2; r = 0.492).

CONCLUSION

Infectious complications are a burden for severely injured patients and occur early in the critical care stay. Severity of admission shock was predictive of infection and represents an opportunity for interventions to improve infectious outcomes. The incidence of infection may also have utility as an end point for clinical trials in trauma hemorrhage given the relationship with patient-experienced outcomes.

LEVEL OF EVIDENCE

Prognostic/epidemiologic study, level II.

Temporal trends of postinjury multiple-organ failure: still resource intensive, morbid, and lethal

BACKGROUND

While the incidence of postinjury multiple-organ failure (MOF) has declined during the past decade, temporal trends of its morbidity, mortality, presentation patterns, and health care resources use have been inconsistent. The purpose of this study was to describe the evolving epidemiology of postinjury MOF from 2003 to 2010 in multiple trauma centers sharing standard treatment protocols.

METHODS

"Inflammation and Host Response to Injury Collaborative Program" institutions that enrolled more than 20 eligible patients per biennial during the 2003 to 2010 study period were included. The patients were aged 16 years to 90 years, sustained blunt torso trauma with hemorrhagic shock (systolic blood pressure < 90 mm Hg, base deficit ≥ 6 mEq/L, blood transfusion within the first 12 hours), but without severe head injury (motor Glasgow Coma Scale [GCS] score < 4). MOF temporal trends (Denver MOF score > 3) were adjusted for admission risk factors (age, sex, body max index, Injury Severity Score [ISS], systolic blood pressure, and base deficit) using survival analysis.

RESULTS

A total of 1,643 patients from four institutions were evaluated. MOF incidence decreased over time (from 17% in 2003-2004 to 9.8% in 2009-2010). MOF-related death rate (33% in 2003-2004 to 36% in 2009-2010), intensive care unit stay, and mechanical ventilation duration did not change over the study period. Adjustment for admission risk factors confirmed the crude trends. MOF patients required much longer ventilation and intensive care unit stay, compared with non-MOF patients. Most of the MOF-related deaths occurred within 2 days of the MOF diagnosis. Lung and cardiac dysfunctions became less frequent (57.6% to 50.8%, 20.9% to 12.5%, respectively), but kidney and liver failure rates did not change (10.1% to 12.5%, 15.2% to 14.1%).

CONCLUSION

Postinjury MOF remains a resource-intensive, morbid, and lethal condition. Lung injury is an enduring challenge and should be a research priority. The lack of outcome improvements suggests that reversing MOF is difficult and prevention is still the best strategy.

LEVEL OF EVIDENCE

Epidemiologic study, level III.

Is Minimally Invasive Spine Surgery Also Minimally Pro-Inflammatory? Muscular Markers, Inflammatory Parameters and Cytokines to Quantify the Operative Invasiveness Assessment in Spine Fusion

Over the last decades, minimally invasive surgery (MIS) techniques entered in the surgical routine due to their major advantage in reducing the unnecessary exposure of tissue and, thus, the trauma. Even in the context of orthopedics and spine surgery these practices have been widely developed and applied. Besides the clinical outcome of the patients, few studies have quantitatively assessed the traumatic and inflammatory effects of a specific surgical technique. Indeed, currently, a universally accepted biological outcome measure, such as a panel of biochemical markers, to define the success of MIS approach is still lacking. We reviewed the literature to collect the published data regarding the quantitative analysis of trauma induced by either conventional or minimally invasive surgery with the aim of highlighting evidence useful to guide future studies. Previous publications show some evidence in support of the hypothesis that MIS approaches are less traumatic, and possibly less pro-inflammatory, than conventional ones. Creatin kinase (as a marker of muscular damage) and C-reactive protein (as a marker of systemic inflammation) seem to reproducibly follow different trends in minimally invasive surgery compared to conventional procedures. Moreover, cytokines, such as interleukin (IL)-6 and IL-10 are also promising markers in this context.

Trauma-hemorrhagic shock induces a CD36-dependent RBC endothelial-adhesive phenotype

OBJECTIVE

Microvascular dysfunction is a key element in the development of the multiple organ dysfunction syndrome. Although the mechanisms for this response are unclear, RBC adhesion to endothelium may initiate intravascular occlusion leading to ischemic tissue injury. Thus, we tested the hypothesis that trauma-hemorrhage induces RBC-endothelial cell adhesion.

DESIGN

Prospective in vivo and in vitro animal study and analysis of patient blood samples.

SETTING

University research laboratory and hospital emergency and trauma units.

INTERVENTION

We initially assayed RBC adhesion to endothelial cells in vitro using RBCs obtained from rats subjected to trauma-hemorrhagic shock or sham shock as well as from severely injured trauma patients. Subsequently, we measured the role of putative RBCs and endothelial cell receptors in the increased RBC-endothelial cell adhesive response.

MAIN RESULTS

In both rats and humans, trauma-hemorrhagic shock increased RBC adhesion to endothelium as well as increasing several putative RBC surface adhesion molecules including CD36. The critical factor leading to RBC-endothelial cell adhesion was increased surface RBC CD36 expression. Adhesion of trauma-hemorrhagic shock RBCs was mediated, at least in part, by the binding of RBC CD36 to its cognate endothelial receptors (αVβ3 and VCAM-1). Gut-derived factors carried in the intestinal lymphatics triggered these trauma-hemorrhagic shock-induced RBC changes because 1) preventing trauma-hemorrhagic shock intestinal lymph from reaching the systemic circulation abrogated the RBC effects, 2) in vitro incubation of naïve whole blood with trauma-hemorrhagic shock lymph replicated the in vivo trauma-hemorrhagic shock-induced RBC changes while 3) injection of trauma-hemorrhagic shock lymph into naïve animals recreated the RBC changes observed after actual trauma-hemorrhagic shock.

CONCLUSIONS

1) Trauma-hemorrhagic shock induces rapid RBC adhesion to endothelial cells in patients and animals. 2) Increased RBC CD36 expression characterizes the RBC-adhesive phenotype. 3) The RBC phenotypic and functional changes were induced by gut-derived humoral factors. These novel findings may explain the microvascular dysfunction occurring after trauma-hemorrhagic shock, sepsis, and other stress states.

Hemorrhage-induced interleukin-1 receptor pathway in lung is suppressed by 3,5-bis(2-fluorobenzylidene)-4-piperidone in a rat model of hypovolemic shock

Severe blood loss in victims of trauma creates an exaggerated inflammatory background that contributes to the development of intravascular coagulopathy and multiple organ dysfunction syndrome. We hypothesized that treatment with diphenyldifluoroketone EF24, an inhibitor of nuclear factor kappa-B, would have salutary effects in hemorrhagic shock. The objective of this study was to investigate the effect of EF24 on the expression of the interleukin-1 receptor (IL-1R) superfamily in a rat model of hypovolemic shock. Hypovolemia was induced by gradually withdrawing approximately 50% of circulating blood, and EF24 was administered intraperitoneally (0.2 mg/kg) in 50 μL of saline. After 6 h of shock, lung tissue was probed immunohistochemically and by immunoblotting to study the expression of Toll-like receptor 4 (TLR4), IL-1R, suppression of tumorigenicity 2 (ST2), and single immunoglobulin IL-1R-related (SIGIRR). The tissue-associated pro-inflammatory cytokines, tumor necrosis factor alpha (TNF-α) and IL-6, were measured by enzyme-linked immunosorbent assay. We observed a reduction in immunoreactive TLR4 and IL-1R1 in lung tissue of rats treated with EF24. Simultaneously, the pulmonary expression of ST2 and SIGIRR (the putative down-regulators of the pro-inflammatory IL-1R pathway) was increased in EF24-treated hemorrhaged rats. The concentration of hemorrhage-induced TNF-α and IL-6 in lung tissue homogenates was also reduced by EF24 treatment. These results confirm our previous in vitro observations in lipopolysaccharide-stimulated dendritic cells that EF24 beneficially modulates the IL-1R pathway and suggest that it could be investigated as an adjunct therapeutic in managing inflammation associated with hemorrhagic shock.

Resistance to systemic inflammation and multi organ damage after global ischemia/reperfusion in the arctic ground squirrel

INTRODUCTION

Cardiac arrest (CA) and hemorrhagic shock (HS) are two clinically relevant situations where the body undergoes global ischemia as blood pressure drops below the threshold necessary for adequate organ perfusion. Resistance to ischemia/reperfusion (I/R) injury is a characteristic of hibernating mammals. The present study sought to determine if arctic ground squirrels (AGS) are protected from systemic inflammation and multi organ damage after CA- or HS-induced global I/R and if, for HS, this protection is dependent upon their hibernation season.

METHODS

For CA, rats and summer euthermic AGS (AGS-EU) were asphyxiated for 8 min, inducing CA. For HS, rats, AGS-EU, and winter interbout arousal AGS (AGS-IBA) were subject to HS by withdrawing blood to a mean arterial pressure of 35 mmHg and maintaining that pressure for 20 min before reperfusion with Ringers. For both I/R models, body temperature (Tb) was kept at 36.5-37.5°C. After reperfusion, animals were monitored for seven days (CA) or 3 hrs (HS) then tissues and blood were collected for histopathology, clinical chemistries, and cytokine level analysis (HS only). For the HS studies, additional groups of rats and AGS were monitored for three days after HS to access survival and physiological impairment.

RESULTS

Rats had increased serum markers of liver damage one hour after CA while AGS did not. For HS, AGS survived 72 hours after I/R whereas rats did not survive overnight. Additionally, only rats displayed an inflammatory response after HS. AGS maintained a positive base excess, whereas the base excess in rats was negative during and after hemorrhage.

CONCLUSIONS

Regardless of season, AGS are resistant to organ damage, systemic inflammation, and multi organ damage after systemic I/R and this resistance is not dependent on their ability to become decrease Tb during insult but may stem from an altered acid/base and metabolic response during I/R.

Resveratrol attenuates hypoxic injury in a primary hepatocyte model of hemorrhagic shock and resuscitation

BACKGROUND

Oxidative stress following hemorrhagic shock and resuscitation (HSR) is regulated, in part, by inflammatory and apoptotic mediators such as necrosis factor κB (NF-κB) and p53. Sirtuin 1 (Sirt-1) is a metabolic intermediary that regulates stress responses by suppressing NF-κB and p53 activity. Resveratrol is a naturally occurring polyphenolic antioxidant and Sirt-1 agonist. The aim of this study was to determine whether resveratrol protects hepatocytes following HSR or hypoxia.

METHODS

In vivo, HSR was achieved in male rats by arterial blood withdrawal to 30 ± 2 mm Hg for 1 hour before resuscitation with or without resveratrol (Res, 30 mg/kg). Hepatic tissue was stained and scored for necrosis, interleukin 6, and Sirt-1 expression. In vitro, primary rat hepatocytes were subjected to 8 hours of hypoxia without or with Res (100 µM). Cells were analyzed immediately or after 6 hours of normoxia, for survival and markers of injury (lactate dehydrogenase assay, lipid peroxidation, and mitochondrial integrity). Cell lysates were collected for cytochrome c analysis and immunoprecipitated using antibodies against NF-κB (p65) or p53.

RESULTS

In vivo, animals subject to HSR exhibited increased expression of markers of hepatocyte damage compared with those sham operated, concomitant with lower Sirt-1 expression. In vitro, hypoxia followed by normoxia resulted in increased cell death, an effect that was blunted by Res. Analysis of cell and mitochondrial function demonstrated that Res inhibited the detrimental effects of hypoxia in isolated hepatocytes.

CONCLUSION

Resveratrol prevents cell death in HSR and exerts a protective effect on the mitochondria in a hepatocyte model of hypoxic injury-reoxygenation possibly via Sirt-1 modulation of p53 and NF-κB activity.

Mitochondrial DNA induces inflammation and increases TLR9/NF-κB expression in lung tissue

Mitochondrial DNA (mtDNA) contains unmethylated CpG motifs that exhibit immune stimulatory capacities. The aim of this study was to investigate whether mtDNA activates the Toll-like receptor 9 (TLR9)/nuclear factor-κB (NF-κB) pathway, thereby contributing to post-traumatic systemic inflammatory response syndrome (SIRS) and lung injury in rats. The effects of mtDNA on macrophage culture were examined in order to elucidate the putative cellular mechanisms. Rats and macrophage cultures were treated with phosphate-buffered saline, nuclear DNA, or mtDNA for 2, 4, 8 and 24 h. Histological analysis of lung tissue was undertaken following hematoxylin and eosin staining, and cytokine levels were assessed by ELISA. NF-κB and IκB-α phosphorylation levels, as well as TLR9 protein expression were determined by western blot analysis; NF-κB, IκB-α and TLR9 mRNA levels were analyzed by RT-PCR. A greater degree of inflammation and lung injury was observed in response to mtDNA. In addition, mtDNA increased serum tumor necrosis factor-α, interleukin (IL)-6 and IL-10 levels in vivo and increased their secretion by cultured macrophages (p<0.05). In lung tissue, mtDNA increased NF-κB, IκB-α and TLR9 mRNA levels (p<0.05); it also increased phosphorylated NF-κB p65 and TLR9 protein levels in the macrophage cultures. Thus, mtDNA may be part of the danger-associated molecular patterns, contributing to the initiation of sterile SIRS through the activation of the TLR9/NF-κB pathway and the induction of pro-inflammatory cytokine production.

Hip fracture aggravates systemic inflammation and lung injury in aged chronic cigarette smoke exposed rats

The aim of this investigation was to examine the influence of hip fracture on systemic inflammation and lung injury in aged chronic cigarette smoke exposed rats. Male Sprague Dawley (SD) aged rats (22-25 months old, 460-570 g) were used. Animals were subjected to either chronic cigarette smoke (CS) or air exposure for 12 weeks. These animals then underwent a sham procedure or hip fracture. Endpoint was 24 h. Systemic inflammation was assessed by TNF-α, IL-6, and IL-10 levels. Pulmonary function, inflammatory cell counts and protein concentrations in BAL, pulmonary pathological changes and scores were obtained to assess lung injury. And TLR4 mRNA expression in lung tissue was determined. The indices mentioned above were unchanged in air-exposed rats after hip fracture. However, CS-exposed animals were found to have increased serum levels of TNF-α, IL-6, and IL-10, impaired pulmonary function, increased inflammatory cell counts and protein concentrations in BAL, and intensified pathologic changes and scores. In addition, lung tissue harvested following CS-exposure demonstrated increased TLR4 mRNA expression. Our results indicate that systemic inflammation and lung injury in aged CS-exposed animals were further aggravated by hip fracture. The overexpression of TLR4 mRNA induced by CS exposure may, at least in part, involve in this process.

Trauma-induced secondary cardiac injury is associated with hyperacute elevations in inflammatory cytokines

INTRODUCTION

Clinical evidence supports the existence of a trauma-induced secondary cardiac injury. Experimental research suggests inflammation as a possible mechanism. The study aimed to determine if there was an early association between inflammation and secondary cardiac injury in trauma patients.

METHODS

A cohort study of critically injured patients between January 2008 and January 2010 was undertaken. Levels of the cardiac biomarkers troponin I and heart-specific fatty acid-binding protein and the cytokines tumor necrosis factor α (TNF-α), interleukin (IL)-6, IL-1β, and IL-8 were measured on admission to hospital, and again at 24 and 72 h. Participants were reviewed for adverse cardiac events (ACEs) and in-hospital mortality.

RESULTS

Of 135 patients recruited, 18 (13%) had an ACE. Patients with ACEs had higher admission plasma levels of TNF-α (5.4 vs. 3.8 pg/mL; P = 0.03), IL-6 (140 vs. 58.9 pg/mL, P = 0.009), and IL-8 (19.3 vs. 9.1 pg/mL, P = 0.03) compared with those without events. Hour 24 cytokines were not associated with events, but IL-8 (14.5 vs. 5.8 pg/mL; P = 0.01) and IL-1β (0.55 vs. 0.19 pg/mL; P = 0.04) were higher in patients with ACEs at 72 hours. Admission IL-6 was independently associated with heart-specific fatty acid-binding protein increase (P < 0.05). Patients who presented with an elevated troponin I combined with either an elevated TNF-α (relative risk [RR], 11.0; 95% confidence interval [CI], 1.8-66.9; P = 0.015), elevated IL-6 (RR, 17.3; 95% CI, 2.9-101.4; P = 0.001), or elevated IL-8 (RR, 15.0; 95% CI, 3.1-72.9; P = 0.008) were at the highest risk of in-hospital death when compared with individuals with normal biomarker and cytokine values.

CONCLUSIONS

There is an association between hyperacute elevations in inflammatory cytokines with cardiac injury and ACEs in critically injured patients. Biomarker evidence of cardiac injury and inflammation on admission is associated with a higher risk of in-hospital death.

A novel experimental model of orthopedic trauma with acute kidney injury in obese Zucker rats

Obesity is associated with an increased risk of acute kidney injury (AKI) after blunt traumatic injury in humans. Because limitations exist in studying trauma in human patients, animal models are necessary to elucidate mechanisms of remote organ injury after trauma. We developed a model of severe orthopedic trauma in lean (LZ) and obese (OZ) Zucker rats, in which OZ develop greater kidney dysfunction after trauma than LZ. Orthopedic trauma was inflicted via bilateral hindlimb soft tissue injury, fibula fracture, and injection of homogenized bone components. Mean arterial pressure (MAP) and heart rate (HR) were measured for 6 h after trauma, and again at 24 h after trauma. Urine was collected for 24 h before and after trauma to measure urine albumin excretion. Glomerular filtration rate (GFR), renal plasma flow (RPF), plasma interleukin-6 (IL-6), and renal macrophage infiltration (ED-1 [CD68 Antibody] immunostaining) were measured in animals with and without trauma. MAP and HR were similar between LZ and OZ throughout the study, with the exception that OZ had a 18 mmHg lower pressure 24 h posttrauma. GFR and RPF were decreased significantly (∼50%), while urine albumin excretion, plasma IL-6, and renal ED-1-positive cells were increased in OZ 24 h after trauma compared to both OZ without trauma and LZ after trauma. In conclusion, these data are consistent with studies in humans that show that AKI develops more frequently in obese than in lean individuals. This model will be an important experimental tool to better understand the underlying mechanisms of poor outcomes after trauma in obese patients.

TIFA upregulation after hypoxia-reoxygenation is TLR4- and MyD88-dependent and associated with HMGB1 upregulation and release

TRAF-interacting protein with a forkhead-associated domain (TIFA) is a tumor necrosis factor receptor-associated factor 6 (TRAF6) binding protein that mediates IL-1 signaling. We recently reported that TIFA mRNA is significantly upregulated early in the liver after trauma and hemorrhagic shock. In this study, we sought to characterize the upregulation of TIFA by hypoxia-reoxygenation and investigate its role in hypoxia-induced signaling. TIFA expression was detected by qRT-PCR and Western blotting in both mouse hemorrhagic shock with resuscitation (HS-R) and hepatocytes exposed to hypoxia-reoxygenation. Involvement of TLR4 and MyD88 was assessed using cells from TLR4(-/-) and MyD88(-/-) mice. The interaction of TIFA with TRAF6 and IRAK-1 was investigated using coimmunoprecipitation in vitro. RNAi was performed to knock down the endogenous expression of the TIFA gene in hepatocytes. High-mobility-group box 1 protein (HMGB1) expression was detected by Western blotting and ELISA, and the activation of NF-κB and MAPK was measured with EMSA and Western blotting. The results showed that TIFA expression was upregulated after HS-R in vivo and hypoxia-reoxygenation in vitro. Further analysis revealed that hypoxia-reoxygenation-induced upregulation of TIFA was TLR4- and MyD88-dependent. Moreover, TIFA was found to associate with TRAF6 constitutively, whereas its association with IRAK-1 was seen only after hypoxia-reoxygenation. Suppression of TIFA by siRNA reduced NF-κB activation and HMGB1 upregulation and release after hypoxia-reoxygenation. Taken together, these data suggest that TIFA is involved in the regulation of cell signaling in hypoxia-reoxygenation. The increase in TIFA level appears to be a feed-forward mechanism involved in TLR4/MyD88-dependent signaling, leading to NF-κB activation and HMGB1 release.

Systemic inflammatory responses and lung injury following hip fracture surgery increases susceptibility to infection in aged rats

Pulmonary infections frequently occur following hip fracture surgery in aged patients. However, the underlying reasons are not fully understood. The present study investigates the systemic inflammatory response and pulmonary conditions following hip fracture surgery as a means of identifying risk factors for lung infections using an aged rodent model. Aged, male Sprague-Dawley rats (8 animals per group) underwent a sham procedure or hip fracture plus femoral intramedullary pinning. Animals were sacrificed 1, 3, and 7 days after the injury. Markers of systemic inflammation and pulmonary injury were analyzed. Both sham-operated and injured/surgical group animals underwent intratracheal inoculation with Pseudomonas aeruginosa 1, 3, and 7 days after surgery. P. aeruginosa counts in blood and bronchoalveolar lavage (BAL) fluid and survival rates were recorded. Serum TNF-α, IL-6, IL-1β, and IL-10 levels and markers of pulmonary injury were significantly increased at 1 and 3 days following hip fracture and surgery. Animals challenged with P. aeruginosa at 1 and 3 days after injury had a significantly decreased survival rate and more P. aeruginosa recovered from blood and BAL fluid. This study shows that hip fracture and surgery in aged rats induced a systemic inflammatory response and lung injury associated with increased susceptibility to infection during the acute phase after injury and surgery.

Regulation of tumor necrosis factor-α-induced microvascular endothelial cell hyperpermeability by recombinant B-cell lymphoma-extra large

BACKGROUND

Tumor necrosis factor-α (TNF-α), a cytotoxic cytokine, induces endothelial cell barrier dysfunction and microvascular hyperpermeability, leading to tissue edema, a hallmark of traumatic injuries. The objective of the present study was to determine whether B-cell lymphoma-extra large (Bcl-xL), an antiapoptotic protein, would regulate and protect against TNF-α-mediated endothelial cell barrier dysfunction and microvascular hyperpermeability.

METHODS

Rat lung microvascular endothelial cells were grown as monolayers on Transwell membranes, and fluorescein isothiocyanate-bovine albumin flux (5 mg/mL) across the monolayer was measured fluorometrically to indicate changes in monolayer permeability. The rat lung microvascular endothelial cell adherens junctional integrity and actin cytoskeleton was studied using β-catenin immunofluorescence and rhodamine phalloidin dye, respectively. Pretreatment of caspase-8 inhibitor (Z-IETD-FMK, 100 μM) for 1 hour and transfection of Bcl-2-homology domain 3-interacting domain death agonist small interfering RNA (10 μM) for 48 hours were performed to study their respective effects on TNF-α-induced (10 ng/mL; 1-hour treatment) monolayer permeability. Recombinant Bcl-xL protein (2.5 μg/ml) was transfected in rat lung microvascular endothelial cells for 1 hour, and its effect on permeability was demonstrated using a permeability assay. Caspase-3 activity was assayed fluorometrically.

RESULTS

Z-IETD-FMK pretreatment protected the adherens junctions and decreased TNF-α-induced monolayer hyperpermeability. Bcl-2-homology domain 3-interacting domain death agonist small interfering RNA transfection attenuated the TNF-α-induced increase in monolayer permeability. Recombinant Bcl-xL protein showed protection against TNF-α-induced actin stress fiber formation, an increase in caspase-3 activity, and monolayer hyperpermeability.

CONCLUSIONS

Our results have demonstrated the protective effects of recombinant Bcl-xL protein against TNF-α-induced endothelial cell adherens junction damage and microvascular endothelial cell hyperpermeability. These findings support the potential for Bcl-xL-based drug development against microvascular hyperpermeability and tissue edema.

Hyperosmolarity attenuates TNF-α-mediated proinflammatory activation of human pulmonary microvascular endothelial cells

Firm neutrophil (PMN)-endothelial (EC) adhesion is crucial to the PMN-mediated hyperinflammation observed in acute lung injury. Hypertonic saline (HTS) used for resuscitation of hemorrhagic shock has been associated with a decreased incidence of PMN-mediated lung injury/acute respiratory distress syndrome. We hypothesize that physiologically accessible hypertonic incubation (170 vs. 140 mM, osmolarity ranging from 360 to 300 mOsm/L) inhibits proinflammatory activation of human pulmonary microvascular endothelial cells (HMVECs). Proinflammatory activation of HMVECs was investigated in response to tumor necrosis factor-α (TNF-α), including interleukin 8 (IL-8) release, intercellular adhesion molecule 1 (ICAM-1) surface expression, PMN adhesion, and signaling mechanisms under both isotonic (control) and hypertonic conditions. Hyperosmolarity alone had no effect on either basal IL-8 release or ICAM-1 surface expression but did lead to concentration-dependent decreases in TNF-α-induced IL-8 release, ICAM-1 surface expression, and PMN-HMVEC adhesion. Conversely, HTS activated p38 mitogen-activated protein kinase (MAPK) and enhanced TNF-α activation of p38 MAPK. Despite this basal activation, hyperosmolar incubation attenuated TNF-α-stimulated IL-8 release and ICAM-1 surface expression and subsequent PMN adherence, while p38 MAPK inhibition did not further influence the effects of hyperosmolar conditions on ICAM-1 surface expression. In addition, TNF-α induced nuclear factor-κB DNA binding, but HTS conditions attenuated this by 31% (P < 0.01). In conclusion, HTS reduces PMN-HMVEC adhesion and TNF-α-induced proinflammatory activation of primary HMVECs via attenuation of nuclear factor-κB signaling.

High incidence of post-injury pneumonia in intensive care-treated trauma patients

INTRODUCTION

Trauma patients are susceptible to post-injury infections. We investigated the incidence, as well as risk factors for development of pneumonia in intensive care unit (ICU)-treated trauma patients. In addition, we report pathogens identified in patients that developed pneumonia.

METHODS

The study cohort consisted of 322 trauma patients admitted to the ICU at a level-one trauma centre following initial resuscitation. Patients 15 years or older with an ICU stay of more than 24 h were included. We investigated pre-hospital and hospital parameters during the first 24 h after admission and their possible association with pneumonia within 10 days of ICU admission.

RESULTS

Majority of the patients were male (78%) and the median age was 41 years. The overall degree of injury was high with a median Injury Severity Score (ISS) of 24. Overall 30-day mortality was 9%. Eighty-five (26%) patients developed pneumonia during their first 10 days in the ICU. Univariate logistic regression revealed that intubation in the field, shock, Glasgow Coma Scale (GCS) 3-8, major surgery within 24 h after admission, massive transfusion and ISS > 24 were all risk factors for subsequent development of pneumonia. In the multivariable model, only GCS 3-8 was identified as an independent risk factor. In 42 out of the 85 cases of pneumonia, the diagnosis was defined by significant growth of at least one pathogen where Enterobacteriaceae and Staphylococcus aureus were the most common.

CONCLUSIONS

Pneumonia is a common complication among ICU-treated trauma patients. Reduced consciousness is an independent risk factor for development of pneumonia after severe injury.

Effects of synthetic colloids on oxidative stress and inflammatory response in hemorrhagic shock: comparison of hydroxyethyl starch 130/0.4, hydroxyethyl starch 200/0.5, and succinylated gelatin

INTRODUCTION

This study compared the effects of hydroxyethyl starch 130/0.4, hydroxyethyl starch 200/0.5, and succinylated gelatin on oxidative stress and the inflammatory response in a rodent hemorrhagic shock model.

METHODS

Sodium pentobarbital-anesthetized adult male Wistar rats (200 g to 220 g) were subjected to a severe volume-controlled hemorrhage using arterial blood withdrawal (30 mL/kg to 33 mL/kg) and resuscitated with a colloid solution at the same volume as blood withdrawal (hydroxyethyl starch 130/0.4, hydroxyethyl starch 200/0.5, or succinylated gelatin). Arterial blood gas parameters were monitored. Malondialdehyde (MDA) content and myeloperoxidase (MPO) activity in the liver, lungs, intestine, and brain were measured two hours after resuscitation. The levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 in the intestine were also measured.

RESULTS

Infusions of hydroxyethyl starch 130/0.4, but not hydroxyethyl starch 200/0.5 or succinylated gelatin, significantly reduced MDA levels and MPO activity in the liver, intestine, lungs and brain, and it also inhibited the production of TNF-α in the intestine two hours after resuscitation. However, no significant difference between hydroxyethyl starch 200/0.5 and succinylated gelatin was observed.

CONCLUSIONS

Hydroxyethyl starch 130/0.4, but not hydroxyethyl starch 200/0.5 or succinylated gelatin, treatment after hemorrhagic shock ameliorated oxidative stress and the inflammatory response in this rat model. No significant differences were observed after hydroxyethyl starch 200/0.5 or succinylated gelatin administration at doses of approximately 33 mL/kg.

Inhibition of Fas-Fas ligand interaction attenuates microvascular hyperpermeability following hemorrhagic shock

Hemorrhagic shock (HS)-induced microvascular hyperpermeability poses a serious challenge in the management of trauma patients. Microvascular hyperpermeability occurs mainly because of the disruption of endothelial cell adherens junctions, where the "intrinsic" apoptotic signaling plays a regulatory role. The purpose of this study was to understand the role of the "extrinsic" apoptotic signaling molecules, particularly Fas-Fas ligand interaction in microvascular endothelial barrier integrity. Rat lung microvascular endothelial cells (RLMECs) were exposed to HS serum in the presence or absence of the Fas ligand inhibitor, FasFc. The effect of HS serum on Fas receptor and Fas ligand expression on RLMECs was determined by flow cytometry. Endothelial cell permeability was determined by monolayer permeability assay and the barrier integrity by β-catenin immunofluorescence. Mitochondrial reactive oxygen species formation was determined using dihydrorhodamine 123 probe by fluorescent microscopy. Mitochondrial transmembrane potential was studied by fluorescent microscopy as well as flow cytometry. Caspase 3 enzyme activity was assayed fluorometrically. Rat lung microvascular endothelial cells exposed to HS serum showed increase in Fas receptor and Fas ligand expression levels. FasFc treatment showed protection against HS serum-induced disruption of the adherens junctions and monolayer hyperpermeability (P < 0.05) in the endothelial cells. Pretreatment with FasFc also decreased HS serum-induced increase in mitochondrial reactive oxygen species formation, restored HS serum-induced drop in mitochondrial transmembrane potential, and reduced HS serum-induced caspase 3 activity in RLMECs. These findings open new avenues for drug development to manage HS-induced microvascular hyperpermeability by targeting the Fas-Fas ligand-mediated pathway.

Effects of biliverdin administration on acute lung injury induced by hemorrhagic shock and resuscitation in rats

Hemorrhagic shock and resuscitation induces pulmonary inflammation that leads to acute lung injury. Biliverdin, a metabolite of heme catabolism, has been shown to have potent cytoprotective, anti-inflammatory, and anti-oxidant effects. This study aimed to examine the effects of intravenous biliverdin administration on lung injury induced by hemorrhagic shock and resuscitation in rats. Biliverdin or vehicle was administered to the rats 1 h before sham or hemorrhagic shock-inducing surgery. The sham-operated rats underwent all surgical procedures except bleeding. To induce hemorrhagic shock, rats were bled to achieve a mean arterial pressure of 30 mmHg that was maintained for 60 min, followed by resuscitation with shed blood. Histopathological changes in the lungs were evaluated by histopathological scoring analysis. Inflammatory gene expression was determined by Northern blot analysis, and oxidative DNA damage was assessed by measuring 8-hydroxy-2' deoxyguanosine levels in the lungs. Hemorrhagic shock and resuscitation resulted in prominent histopathological damage, including congestion, edema, cellular infiltration, and hemorrhage. Biliverdin administration prior to hemorrhagic shock and resuscitation significantly ameliorated these lung injuries as judged by histopathological improvement. After hemorrhagic shock and resuscitation, inflammatory gene expression of tumor necrosis factor-α and inducible nitric oxide synthase were increased by 18- and 8-fold, respectively. Inflammatory gene expression significantly decreased when biliverdin was administered prior to hemorrhagic shock and resuscitation. Moreover, after hemorrhagic shock and resuscitation, lung 8-hydroxy-2' deoxyguanosine levels in mitochondrial DNA expressed in the pulmonary interstitium increased by 1.5-fold. Biliverdin administration prior to hemorrhagic shock and resuscitation decreased mitochondrial 8-hydroxy-2' deoxyguanosine levels to almost the same level as that in the control animals. We also confirmed that biliverdin administration after hemorrhagic shock and resuscitation had protective effects on lung injury. Our findings suggest that biliverdin has a protective role, at least in part, against hemorrhagic shock and resuscitation-induced lung injury through anti-inflammatory and anti-oxidant mechanisms.

Modulation of the unfolded protein response during hepatocyte and cardiomyocyte apoptosis in trauma/hemorrhagic shock

Trauma with hemorrhagic shock (T/HS), has been shown to result in liver injury marked by hepatocyte apoptosis and heart failure marked by cardiomyocyte apoptosis, both of which we have shown to be prevented by IL-6 administration at resuscitation, and Stat3 largely mediated this. As specific mediators have not been delineated, we investigated the unfolded protein response (UPR), which, with marked activation, can lead to apoptosis. Prior studies of hepatic and cardiac injury examined limited repertoires of UPR elements, making it difficult to assess the role of the UPR in T/HS. This study describes the first global examination of the UPR transcriptome in the liver and heart following T/HS, demonstrating organ-specific UPR transcriptome changes. The non-canonical UPR chaperone, Hsp70, was most dysregulated following T/HS and may contribute to hepatocyte protection via an IL-6-mediated pathway, identifying a potential new therapeutic strategy to prevent hepatocyte death and organ dysfunction in T/HS.

Uncoupling mitochondrial activity maintains body [Formula: see text] during hemorrhage-induced O2 deficit in the anesthetized rat

During a hemorrhagic shock (HS), O2 uptake ( [Formula: see text] ) decreases as soon as the rate of O2 delivery ( [Formula: see text] ) drops below a "critical level", a response accounted for by the reduction in mitochondrial O2supply. In urethane-anesthetized rats, [Formula: see text] was decreased within 20min from 21.5 to 2.8mlmin(-1) by slowly withdrawing 18mlkg(-1) of blood. This led to a reduction in [Formula: see text] from 6.1 to 2.4mlmin(-1) (n=5, p<0.01). Decoupling mitochondrial oxidative activity by injecting 2,4-DNP (6mgkg(-1), iv) before HS elevated [Formula: see text] to 11.9±1.2mlmin(-1) (n=6, p<0.01), which remained above control HS values throughout most of the hemorrhage. This was associated with higher levels of O2 extraction, cardiac output and ventilation than in control HS. [Formula: see text] relationship was shifted upward and to the left following DNP. In conclusion, cellular and systemic mechanisms, decreasing O2demand, account for a large part of HS induced [Formula: see text] decline resulting in an additional reduction in [Formula: see text] .

Circulating histones are mediators of trauma-associated lung injury

RATIONALE

Acute lung injury is a common complication after severe trauma, which predisposes patients to multiple organ failure. This syndrome largely accounts for the late mortality that arises and despite many theories, the pathological mechanism is not fully understood. Discovery of histone-induced toxicity in mice presents a new dimension for elucidating the underlying pathophysiology.

OBJECTIVES

To investigate the pathological roles of circulating histones in trauma-induced lung injury.

METHODS

Circulating histone levels in patients with severe trauma were determined and correlated with respiratory failure and Sequential Organ Failure Assessment (SOFA) scores. Their cause-effect relationship was studied using cells and mouse models.

MEASUREMENTS AND MAIN RESULTS

In a cohort of 52 patients with severe nonthoracic blunt trauma, circulating histones surged immediately after trauma to levels that were toxic to cultured endothelial cells. The high levels were significantly associated with the incidence of acute lung injury and SOFA scores, as well as markers of endothelial damage and coagulation activation. In in vitro systems, histones damaged endothelial cells, stimulated cytokine release, and induced neutrophil extracellular trap formation and myeloperoxidase release. Cellular toxicity resulted from their direct membrane interaction and resultant calcium influx. In mouse models, cytokines and markers for endothelial damage and coagulation activation significantly increased immediately after trauma or histone infusion. Pathological examinations showed that lungs were the predominantly affected organ with edema, hemorrhage, microvascular thrombosis, and neutrophil congestion. An anti-histone antibody could reduce these changes and protect mice from histone-induced lethality.

CONCLUSIONS

This study elucidates a new mechanism for acute lung injury after severe trauma and proposes that circulating histones are viable therapeutic targets for improving survival outcomes in patients.

Oxygen deficit and H2S in hemorrhagic shock in rats

Introduction

Hemorrhagic shock induced O₂ deficit triggers inflammation and multiple organ failure (MOF). Endogenous H₂S has been proposed to be involved in MOF since plasma H₂S concentration appears to increase in various types of shocks and to predict mortality. We tested the hypothesis that H₂S increases during hemorrhagic shock associated with O₂ deficit, and that enhancing H₂S oxidation by hydroxocobalamin could reduce inflammation, O₂ deficit or mortality.

Methods

We used a urethane anesthetized rat model, where 25 ml/kg of blood was withdrawn over 30 minutes. O₂ deficit, lactic acid, tumor necrosis factor (TNF)-alpha and H₂S plasma concentrations (Siegel method) were measured before and after the bleeding protocol in control animals and animals that received 140 mg/kg of hydroxocobalamin. The ability to oxidize exogenous H₂S of the plasma and supernatants of the kidney and heart homogenates was determined in vitro.

Results

We found that withdrawing 25 ml/kg of blood led to an average oxygen deficit of 122 ± 23 ml/kg. This O₂ deficit was correlated with an increase in the blood lactic acid concentration and mortality. However, the low level of absorbance of the plasma at 670 nm (A₆₇₀), after adding N, N-Dimethyl-p-phenylenediamine, that is, the method used for H₂S determination in previous studies, did not reflect the presence of H₂S, but was a marker of plasma turbidity. There was no difference in plasmatic A₆₇₀ before and after the bleeding protocol, despite the large oxygen deficit. The plasma sampled at the end of bleeding maintained a very large ability to oxidize exogenous H₂S (high μM), as did the homogenates of hearts and kidneys harvested just after death. Hydroxocobalamin concentrations increased in the blood in the μM range in the vitamin B12 group, and enhanced the ability of plasma and kidneys to oxidize H₂S. Yet, the survival rate, O₂ deficit, H₂S plasma concentration, blood lactic acid and TNF-alpha levels were not different from the control group.

Conclusions

In the presence of a large O₂ deficit, H₂S did not increase in the blood in a rat model of untreated hemorrhagic shock. Hydroxocobalamin, while effective against H₂S in vitro, did not affect the hemodynamic profile or outcome in our model.

Altered leucocyte progenitor profile in human bone marrow from patients with major trauma during the recovery phase

Background

Changes in human bone marrow associated with the systemic inflammatory response to injury are little understood. It was hypothesized that major trauma results in an altered bone marrow leucocyte progenitor profile, with either uniform depletion or the balance between multipotent and committed progenitors varying, depending on whether self-renewal is favoured over differentiation.

Methods

Bone marrow aspirate and peripheral blood samples were obtained at definitive surgery in adults with pelvic fractures from blunt trauma (major trauma with Injury Severity Score (ISS) at least 18, or isolated fractures) and control patients undergoing iliac crest bone grafting. ISS, interval to surgery and transfusion in the first 24 h were recorded. Bone marrow aspirate flow cytometry was used to identify haemopoietic progenitor cells (CD34+), multipotent cells (CD34+ CD45+ CD38−) and oligopotent cells (CD34+ CD45+ CD38lo/+ and CD34+ CD45+ CD38BRIGHT(++ +) subsets). Peripheral blood levels of inflammatory markers were measured, and the ratio of immature to mature (CD35−/CD35+) granulocytes was determined.

Results

The median (range) interval between injury and sampling was 7 (1–21) and 5 (1–21) days in the major trauma and isolated fracture groups respectively. The CD34+ pool was significantly depleted in the major trauma group (P = 0·017), particularly the CD34+ CD45+ CD38BRIGHT(++ +) oligopotent pool (P = 0·003). Immature CD35− granulocytes increased in bone marrow with increasing injury severity (P = 0·024) and massive transfusion (P = 0·019), and in peripheral blood with increasing interval to surgery (P = 0·005).

Conclusion

Major blunt trauma resulted in changes in the bone marrow CD34+ progenitor pool. At the point in recovery when these samples were obtained, oligopotent progenitors were lost from the bone marrow, with continued release of immature cells.

The 5-lipoxygenase pathway is required for acute lung injury following hemorrhagic shock

The cellular and biochemical mechanisms leading to acute lung injury (ALI) and subsequent multiple organ failure are only partially understood. To study the potential role of eicosanoids, particularly leukotrienes, as possible mediators of ALI, we used a murine experimental model of ALI induced by hemorrhagic shock after blood removal via cardiac puncture. Neutrophil sequestration, as shown by immunofluorescence and protein leakage into the alveolar space were measured as markers of injury. We used liquid chromatography coupled to tandem mass spectrometry to unequivocally identify several eicosanoids in the bronchoalveolar lavage fluid of experimental animals. MK886, a specific inhibitor of the 5-lipoxygenase (5-LO) pathway, and transgenic mice deficient in 5-LO were used to determine the role of this enzymatic pathway in this model. Leukotriene B4 and leukotriene C4 were consistently elevated in shock-treated mice compared with sham-treated mice. MK886 attenuated neutrophil infiltration and protein extravasation induced by hemorrhagic shock. 5-Lipoxygenase-deficient mice showed reduced neutrophil infiltration and protein extravasation after shock treatment, indicating greatly reduced lung injury. These results support the hypothesis that 5-LO, most likely through the generation of leukotrienes, plays an important role in the pathogenesis of ALI induced by hemorrhagic shock in mice. This pathway could represent a new target for pharmacological intervention to reduce lung damage following severe primary injury.