Systemic inflammation after trauma

Red cell distribution width predicts out of hospital outcomes in critically ill emergency general surgery patients

Introduction

Red cell distribution width (RDW) is associated with mortality and bloodstream infection risk in critically ill patients. We hypothesized that an increase in RDW at hospital discharge in critically ill patients who received emergency general surgery (EGS) would be associated with increased mortality after hospital discharge.

Methods

We performed a two-center observational study of patients treated in medical and surgical intensive care units. We studied 1567 patients, who received critical care between 1998 and 2012 who underwent EGS and survived hospitalization. The exposure of interest was RDW within 24 hours of hospital discharge and categorized a priori in quintiles as ≤13.3%, 13.3% to 14.0%, 14.0% to 14.7%, 14.7% to 15.8%, 15.8% to 17.0% and >17.0%. The primary outcome was 90-day all-cause mortality. Adjusted ORs were estimated by multivariable logistic regression models with inclusion of covariate terms for age, race, gender, Deyo-Charlson Index, sepsis and number of organs with acute failure.

Results

The cohort patients were 51.4% male and 23.2% non-white. 23.9% had sepsis and the mean age was 58 years. 90-day postdischarge mortality was 6.8%. Patients with a discharge RDW 15.8% to 17.0% or RDW >17.0% have an adjusted OR of 90-day postdischarge mortality of 3.64 (95% CI 1.04 to 12.68; p=0.043) or 4.58 (95% CI 1.32 to 15.93; p=0.02), respectively, relative to patients with a discharge RDW ≤13.3%. Further, patients with a discharge RDW ≥15.8 have an adjusted OR of 30-day hospital readmission of 2.12 (95% CI 1.17 to 3.83; p=0.013) relative to patients with a discharge RDW ≤13.3%.

Conclusions

In EGS patients requiring critical care who survive hospitalization, an elevated RDW at the time of discharge is a robust predictor of all-cause patient mortality and hospital readmission after discharge.

Level of evidence

Level II, prognostic retrospective study.

Necrotizing vasculitis in immediate response to a shoulder dislocation

The shoulder is one of the most commonly dislocated joints in the human body. Complications usually represent local damage. However, it is unclear whether joint dislocations can have systemic sequellae as wSell. Here we present the case of an 86-year-old female who developed necrotizing cryoglobulinaemic vasculitis in immediate response to a shoulder dislocation. We hypothesize there might be a link between trauma and systemic disease.

Minimizing ICU Neurological Dysfunction with Dexmedetomidine-induced Sleep (MINDDS): protocol for a randomised, double-blind, parallel-arm, placebo-controlled trial

INTRODUCTION

Delirium, which is prevalent in postcardiac surgical patients, is an acute brain dysfunction characterised by disturbances in attention, awareness and cognition not explained by a pre-existing neurocognitive disorder. The pathophysiology of delirium remains poorly understood. However, basic science and clinical studies suggest that sleep disturbance may be a modifiable risk factor for the development of delirium. Dexmedetomidine is a α-2A adrenergic receptor agonist medication that patterns the activity of various arousal nuclei similar to sleep. A single night-time loading dose of dexmedetomidine promotes non-rapid eye movement sleep stages N2 and N3 sleep. This trial hypothesises dexmedetomidine-induced sleep as pre-emptive therapy for postoperative delirium.

METHODS AND ANALYSIS

The MINDDS (Minimizing ICU Neurological Dysfunction with Dexmedetomidine-induced Sleep) trial is a 370-patient block-randomised, placebo-controlled, double-blinded, single-site, parallel-arm superiority trial. Patients over 60 years old, undergoing cardiac surgery with planned cardiopulmonary bypass, will be randomised to receive a sleep-inducing dose of dexmedetomidine or placebo. The primary outcome is the incidence of delirium on postoperative day 1, assessed with the Confusion Assessment Method by staff blinded to the treatment assignment. To ensure that the study is appropriately powered for the primary outcome measure, patients will be recruited and randomised into the study until 370 patients receive the study intervention on postoperative day 0. Secondary outcomes will be evaluated by in-person assessments and medical record review for in-hospital end points, and by telephone interview for 30-day, 90-day and 180-day end points. All trial outcomes will be evaluated using an intention-to-treat analysis plan. Hypothesis testing will be performed using a two-sided significance level (type I error) of α=0.05. Sensitivity analyses using the actual treatment received will be performed and compared with the intention-to-treat analysis results. Additional sensitivity analyses will assess the potential impact of missing data due to loss of follow-up.

ETHICS AND DISSEMINATION

The Partners Human Research Committee approved the MINDDS trial. Recruitment began in March 2017. Dissemination plans include presentations at scientific conferences, scientific publications and popular media.

TRIAL REGISTRATION NUMBER

NCT02856594.

Impact of pelvic fractures on the early clinical outcomes of severely injured trauma patients

BACKGROUND

Pelvic fractures contribute to morbidity and mortality following injury. We sought to study the impact of pelvic fractures on the clinical course and outcomes of trauma patients with a pelvic fracture in comparison to patients with similar injury severity without pelvic fracture to identify potential parameters to track patients' clinical course post-injury.

METHODS

A cohort of 206 consecutive blunt trauma survivors, studied over a 5-year period in a level I trauma center of which 75 patients (36.4%) had a pelvic fracture, was included in the study. To perform a retrospective cohort study with matched controls, 60 patients of the pelvic fracture group [(PF), 41 males and 19 females; age: 40 ± 17; injury severity score (ISS): 26.6 ± 9.3] were compared to 60 patients without pelvic fracture (non-PF) trauma as controls (41 males and 19 females; age: 40 ± 13; ISS: 26.9 ± 7.7), both with matching age (±5 years), sex, and ISS (±5 points).

RESULTS

Statistically significant differences were observed in Intensive Care Unit (ICU) length of stay (LOS), total LOS, and Marshall MOD score between PF and non-PF groups, respectively. Acid-base markers such as pH, lactate, LDH, and base deficit were all significantly altered in PF compared to non-PF cohort upon admission. Moreover, our analysis showed significant differences in inflammatory biomarkers (Prolactin, CRP, and IL-6), and clinical parameters (CPK, Hgb, Platelets count, and WBC) over the 7-day clinical course in patients with PF when compared to non-PF cohort.

CONCLUSION

In this matched cohort, patients with pelvic fractures exhibited biochemical and physiological alterations upon admission. Furthermore, our results suggest that pelvic fracture affects the clinical outcomes in severely injured patients, independently of injury severity, mechanism of injury, age or gender.

Isolated Brain Trauma in Cats Triggers Rapid Onset of Hypovolemia

Background

Hemodynamic instability responsive to fluid resuscitation is common after a traumatic brain injury (TBI), also in the absence of systemic hemorrhage. The present study tests if an isolated severe TBI induces a decrease in plasma volume (PV).

Methods

The study was performed in three groups of anesthetized and tracheostomized male cats (n = 21). In one group (n = 8), the cats were prepared with a cranial borehole (10 mm i.d) used to expose the brain to a fluid percussion brain injury (FPI) (1.90–2.20 bar), and two smaller cranial boreholes (4 mm i.d) for insertion of an intracranial pressure (ICP) and a microdialysis catheter. To differentiate the effect of FPI from that of the surgical preparation, a sham group was exposed to the same surgical preparation but no FPI trauma (n = 8). A control group had no brain trauma and no surgical preparation (n = 5). PV was determined by a ¹²⁵I-albumin dilution technique. PV, electrolytes, pH, BE (base excess), hematocrit (Hct), P_aO₂, and P_aCO₂ were measured at baseline and after 3 h. Mean arterial pressure (MAP) was measured continuously. ICP was measured in the FPI and the sham group.

Results

In the FPI group, PV decreased by 11.2 mL/kg from 31.7 mL/kg (p < 0.01) with a simultaneous increase in Hct and decrease in pH. In the sham group, PV decreased by 5.7 mL/kg from 32.7 mL/kg (p < 0.01). The control group showed no PV reduction.

Conclusions

The results support that an isolated severe head trauma triggers a significant and rapid reduction in PV, most likely due to vascular leak.

Clinical Significance of Tissue Factor and CD13 Double-Positive Microparticles in Sirs Patients with Trauma and Severe Sepsis

Activated immune cells such as monocytes are key factors in systemic inflammatory response syndrome (SIRS) following trauma and sepsis. Activated monocytes induce almost all tissue factor (TF) expression contributing to inflammation and coagulation. TF and CD13 double-positive microparticles (TF/CD13MPs) are predominantly released from these activated monocytes. This study aimed to evaluate TF/CD13MPs and assess their usefulness as a biomarker of pathogenesis in early SIRS following trauma and sepsis. This prospective study comprising 24 trauma patients, 25 severe sepsis patients, and 23 healthy controls was conducted from November 2012 to February 2015. Blood samples were collected from patients within 24 h after injury and diagnosis of severe sepsis and from healthy controls. Numbers of TF/CD13MPs were measured by flow cytometry immediately thereafter. Injury Severity Score (ISS) and Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) scores were calculated at patient enrollment. APACHE II and SOFA scores and International Society of Thrombosis and Haemostasis (ISTH) overt disseminated intravascular coagulation (DIC) diagnostic criteria algorithm were calculated at the time of enrollment of severe sepsis patients. Numbers of TF/CD13MPs were significantly increased in both trauma and severe sepsis patients versus controls and correlated significantly with ISS and APACHE II score in trauma patients and with APACHE II and ISTH DIC scores in severe sepsis patients. Increased numbers of TF/CD13MPs correlated significantly with severities in the acute phase in trauma and severe sepsis patients, suggesting that TF/CD13MPs are important in the pathogenesis of early SIRS following trauma and sepsis.

Trauma and Endothelial Glycocalyx: The Microcirculation Helmet?

Trauma represents a remarkable social and economical burden, being a leading cause of death and morbidity in the young population. The Endothelial Glycocalyx (EG) is a web of membrane bound to the luminal side of the blood vessels endothelium. Its role includes maintenance of the vascular permeability barrier and mediation of shear response. The contribution of the EG to a number of clinical conditions, sepsis, and ischemia/reperfusion injury among others has been well studied. With this review we initially explore the role of the EG in the microcirculatory dysfunction associated with trauma. Subsequently, we investigate the impact of fluid administration on the EG, including its potential of protecting the microcirculation from the detrimental effects of trauma. Particular emphasis is reserved to the role of inflammatory modulation and sensible fluid resuscitation.

Systemic cell cycle activation is induced following complex tissue injury in axolotl

Activation of progenitor cells is crucial to promote tissue repair following injury in adult animals. In the context of successful limb regeneration following amputation, progenitor cells residing within the stump must re-enter the cell cycle to promote regrowth of the missing limb. We demonstrate that in axolotls, amputation is sufficient to induce cell-cycle activation in both the amputated limb and the intact, uninjured contralateral limb. Activated cells were found throughout all major tissue populations of the intact contralateral limb, with internal cellular populations (bone and soft tissue) the most affected. Further, activated cells were additionally found within the heart, liver, and spinal cord, suggesting that amputation induces a common global activation signal throughout the body. Among two other injury models, limb crush and skin excisional wound, only limb crush injuries were capable of inducing cellular responses in contralateral uninjured limbs but did not achieve activation levels seen following limb loss. We found this systemic activation response to injury is independent of formation of a wound epidermis over the amputation plane, suggesting that injury-induced signals alone can promote cellular activation. In mammals, mTOR signaling has been shown to promote activation of quiescent cells following injury, and we confirmed a subset of activated contralateral cells is positive for mTOR signaling within axolotl limbs. These findings suggest that conservation of an early systemic response to injury exists between mammals and axolotls, and propose that a distinguishing feature in species capable of full regeneration is converting this initial activation into sustained and productive growth at the site of regeneration.

Thromboelastometry in trauma care: a place in the 2018 Belgian health care system?

Introduction Evidence supporting the use of Thromboelastography (TEG®) and rotational thromboelastometric (ROTEM®) in the trauma setting remains limited. We present the results of a practical evaluation of the potential interest of ROTEM® in the diagnosis of acute coagulopathy and the need for emergent blood product transfusion in the general trauma population of a non-trauma Belgian emergency department. Methods Extracting a convenience cohort from the initial prospective TICCS study, we performed a retrospective analysis to test the following hypothesis: ROTEM® might be helpful to discriminate trauma patients with or without acute coagulopathy. Fifty patients were included and ROTEM® results were compared to conventional coagulation tests results, blood transfusion need and outcome. Results With a negative predictive value of 97.6% and a positive predictive value of 42.9%, a strictly normal ROTEM® profile at the time of admission seems to be able to exclude the presence of acute coagulopathy. ROTEM® also seems to be accurate in identifying patients without the need for emergent blood product transfusions. Conclusion In a population of trauma patients of a Belgian general emergency department, a strictly normal coagulation profile evaluated by ROTEM® at hospital entry is associated with a normal coagulation profile evaluated by INR and fibrinogen levels and the absence of any indication of blood product transfusion. ROTEM® may be useful for preselection of trauma patients at risk for coagulopathy within the global trauma population. This, however, would need confirmation in further investigations.

TRIAL REGISTRATION

clinicaltrials.gov NCT02132208 Registered 6 May 2014.

Fever and hypothermia in systemic inflammation

Systemic inflammation-associated syndromes (e.g., sepsis and septic shock) often have high mortality and remain a challenge in emergency medicine. Systemic inflammation is usually accompanied by changes in body temperature: fever or hypothermia. In animal studies, systemic inflammation is often modeled by administering bacterial lipopolysaccharide, which triggers autonomic and behavioral thermoeffector responses and causes either fever or hypothermia, depending on the dose and ambient temperature. Fever and hypothermia are regulated changes of body temperature, which correspond to mild and severe forms of systemic inflammation, respectively. Mediators of fever and hypothermia are called endogenous pyrogens and cryogens; they are produced when the innate immune system recognizes an infectious pathogen. Upon an inflammatory challenge, hepatic and pulmonary macrophages (and later brain endothelial cells) start to release lipid mediators, of which prostaglandin (PG) E₂ plays the key role, and cytokines. Blood PGE₂ enters the brain and triggers fever. At later stages of fever, PGE₂ synthesized within the blood-brain barrier maintains fever. In both cases, PGE₂ is synthesized by cyclooxygenase-2 and microsomal PGE₂synthase-1. Mediators of hypothermia are not well established. Both fever and hypothermia are beneficial host defense responses. Based on evidence from studies in laboratory animals and clinical trials in humans, fever is beneficial for fighting mild infection. Based mainly on animal studies, hypothermia is beneficial in severe systemic inflammation and infection.

Retrospective evaluation of 140 dogs involved in road traffic accidents

This study has retrospectively reviewed the medical records of 140 dogs sustaining road traffic accident (RTA), and has examined the population characteristics, medical history, injury type, physical examination, emergency laboratory tests and radiography findings, the animal trauma triage (ATT) score, the length of hospitalisation, the complications and the outcome. The survival rate was 83.2 per cent. Younger dogs sustained more frequently lung contusions and limb fractures, while larger dogs more frequently suffered limb fractures, and smaller dogs and older ones sustained more frequently pelvic fractures and sacroiliac luxation (P<0.05 for all). Dogs sustaining orthopaedic injuries required longer hospitalisation (P<0.001). The survival rates of non-ambulatory dogs (P<0.001) and those with neurological abnormalities (P<0.001), abnormal body temperature (P=0.001), hyperglycaemia (P=0.026) or hypoproteinaemia (P=0.04) at presentation were lower compared with those in which these were absent. The number of injured body systems was significantly (P<0.001) and positively associated with death. Dogs surviving RTA to presentation to the hospital have a good prognosis for survival to discharge. Older age, and high ATT score, abnormal body temperature, neurological deficits, hyperglycaemia and hypoproteinaemia at presentation, and occurrence of multiorgan trauma are negative prognostic indicators in such dogs.

The Effects of Ex Vivo Administration of Granulocyte-Macrophage Colony-Stimulating Factor and Endotoxin on Cytokine Release of Whole Blood Are Determined by Priming Conditions

Background

Lipopolysaccharide- (LPS-) induced tumour necrosis factor alpha (TNFα) secretion in critically ill patients can be considered as a measure of immune responsiveness. It can be enhanced by granulocyte-macrophage colony stimulating factor (GM-CSF). We investigated the effect of GM-CSF on ex vivo stimulated cytokine production using various preincubation regimens in healthy donors and patients with sepsis.

Results

The maxima for the stimuli occurred 3 hours after stimulation. In donors, there was an increase (p < 0.001) of LPS-induced TNFα levels following incubation with GM-CSF. The simultaneous incubation with GM-CSF and LPS caused an inhibition of TNFα production (p < 0.001). Postincubation with GM-CSF did not yield any difference. In patients, preincubation with GM-CSF yielded an enhanced ex vivo TNFα-response when TNFα levels were low. Patients with increased TNFα concentrations did not show a GM-CSF stimulation effect. The GM-CSF preincubation yielded an increase of IL-8 production in patients and donors.

Conclusions

This study demonstrates the immune-modulating properties of GM-CSF depending on the absence or presence of LPS or systemic TNFα. The timing of GM-CSF administration may be relevant for the modulation of the immune system in sepsis. The lack of stimulation in patients with high TNFα may represent endotoxin tolerance.

Soluble fibrin causes an acquired platelet glycoprotein VI signaling defect: implications for coagulopathy

Essentials Collagen and thrombin when used simultaneously generate highly activated platelets. The effect of thrombin stimulation on subsequent glycoprotein VI (GPVI) function was observed. Soluble fibrin, but not protease activated receptor (PAR) activation, prevented GPVI activation. Circulating soluble fibrin in coagulopathic blood may cause an acquired GPVI signaling defect.

SUMMARY

Background In coagulopathic blood, circulating thrombin may drive platelet dysfunction. Methods/Results Using calcium dye-loaded platelets, the effect of thrombin exposure and soluble fibrin generation on subsequent platelet GPVI function was investigated. Exposure of apixaban-treated platelet-rich plasma (12% PRP) to thrombin (1-10 nm), but not ADP or thromboxane mimetic U46619 exposure, dramatically blocked subsequent GPVI activation by convulxin, collagen-related peptide or fibrillar collagen. Consistent with soluble fibrin multimerizing and binding GPVI, the onset of convulxin insensitivity required 200-500 s of thrombin exposure, was not mimicked by exposure to PAR-1/4 activating peptides, was not observed with washed platelets, and was blocked by fibrin polymerization inhibitor (GPRP) or factor XIIIa inhibitor (T101). PAR-1 signaling through Gαq was not required because vorapaxar blocked thrombin-induced calcium mobilization but had no effect on the ability of thrombin to impair GPVI-signaling. Convulxin insensitivity was unaffected by the metalloprotease inhibitor GM6001 or the αIIb β3 antagonist GR144053, indicating negligible roles for GPVI shedding or αIIb β3 binding of fibrin. Thrombin treatment of washed platelets resuspended in purified fibrinogen also produced convulxin insensitivity that was prevented by GPRP. Exposure of apixaban/PPACK-treated whole blood to thrombin-treated fibrinogen resulted in > 50% decrease in platelet deposition in a collagen microfluidic assay that required soluble fibrin assembly. Conclusions Conversion of only 1% plasma fibrinogen in coagulopathic blood would generate 90 nm soluble fibrin, far exceeding ~1 nmGPVI in blood. Soluble fibrin, rather than thrombin-induced platelet activation throuh PAR-1 and PAR-4, downregulated GPVI-signaling in response to stimuli, and may lead to subsequent hypofunction of endogenous or transfused platelets.

A new multiple trauma model of the mouse

Background

Blunt trauma is the most frequent mechanism of injury in multiple trauma, commonly resulting from road traffic collisions or falls. Two of the most frequent injuries in patients with multiple trauma are chest trauma and extremity fracture. Several trauma mouse models combine chest trauma and head injury, but no trauma mouse model to date includes the combination of long bone fractures and chest trauma. Outcome is essentially determined by the combination of these injuries. In this study, we attempted to establish a reproducible novel multiple trauma model in mice that combines blunt trauma, major injuries and simple practicability.

Methods

Ninety-six male C57BL/6 N mice (n = 8/group) were subjected to trauma for isolated femur fracture and a combination of femur fracture and chest injury. Serum samples of mice were obtained by heart puncture at defined time points of 0 h (hour), 6 h, 12 h, 24 h, 3 d (days), and 7 d.

Results

A tendency toward reduced weight and temperature was observed at 24 h after chest trauma and femur fracture. Blood analyses revealed a decrease in hemoglobin during the first 24 h after trauma. Some animals were killed by heart puncture immediately after chest contusion; these animals showed the most severe lung contusion and hemorrhage. The extent of structural lung injury varied in different mice but was evident in all animals. Representative H&E-stained (Haematoxylin and Eosin-stained) paraffin lung sections of mice with multiple trauma revealed hemorrhage and an inflammatory immune response. Plasma samples of mice with chest trauma and femur fracture showed an up-regulation of IL-1β (Interleukin-1β), IL-6, IL-10, IL-12p70 and TNF-α (Tumor necrosis factor- α) compared with the control group. Mice with femur fracture and chest trauma showed a significant up-regulation of IL-6 compared to group with isolated femur fracture.

Conclusions

The multiple trauma mouse model comprising chest trauma and femur fracture enables many analogies to clinical cases of multiple trauma in humans and demonstrates associated characteristic clinical and pathophysiological changes. This model is easy to perform, is economical and can be used for further research examining specific immunological questions.

Pyruvate enhancement of cardiac performance: Cellular mechanisms and clinical application

Cardiac contractile function is adenosine-5'-triphosphate (ATP)-intensive, and the myocardium's high demand for oxygen and energy substrates leaves it acutely vulnerable to interruptions in its blood supply. The myriad cardioprotective properties of the natural intermediary metabolite pyruvate make it a potentially powerful intervention against the complex injury cascade ignited by myocardial ischemia-reperfusion. A readily oxidized metabolic substrate, pyruvate augments myocardial free energy of ATP hydrolysis to a greater extent than the physiological fuels glucose, lactate and fatty acids, particularly when it is provided at supra-physiological plasma concentrations. Pyruvate also exerts antioxidant effects by detoxifying reactive oxygen and nitrogen intermediates, and by increasing nicotinamide adenine dinucleotide phosphate reduced form (NADPH) production to maintain glutathione redox state. These enhancements of free energy and antioxidant defenses combine to augment sarcoplasmic reticular Ca²⁺ release and re-uptake central to cardiac mechanical performance and to restore β-adrenergic signaling of ischemically stunned myocardium. By minimizing Ca²⁺ mismanagement and oxidative stress, pyruvate suppresses inflammation in post-ischemic myocardium. Thus, pyruvate administration stabilized cardiac performance, augmented free energy of ATP hydrolysis and glutathione redox systems, and/or quelled inflammation in a porcine model of cardiopulmonary bypass, a canine model of cardiac arrest-resuscitation, and a caprine model of hypovolemia and hindlimb ischemia-reperfusion. Pyruvate's myriad benefits in preclinical models provide the mechanistic framework for its clinical application as metabolic support for myocardium at risk. Phase one trials have demonstrated pyruvate's safety and efficacy for intravenous resuscitation for septic shock, intracoronary infusion for heart failure and as a component of cardioplegia for cardiopulmonary bypass. The favorable outcomes of these trials, which argue for expanded, phase three investigations of pyruvate therapy, mirror findings in isolated, perfused hearts, underscoring the pivotal role of preclinical research in identifying clinical interventions for cardiovascular diseases. Impact statement This article reviews pyruvate's cardioprotective properties as an energy-yielding metabolic fuel, antioxidant and anti-inflammatory agent in mammalian myocardium. Preclinical research has shown these properties make pyruvate a powerful intervention to curb the complex injury cascade ignited by ischemia and reperfusion. In ischemically stunned isolated hearts and in large mammal models of cardiopulmonary bypass, cardiac arrest-resuscitation and hypovolemia, intracoronary pyruvate supports recovery of myocardial contractile function, intracellular Ca²⁺ homeostasis and free energy of ATP hydrolysis, and its antioxidant actions restore β-adrenergic signaling and suppress inflammation. The first clinical trials of pyruvate for cardiopulmonary bypass, fluid resuscitation and intracoronary intervention for congestive heart failure have been reported. Receiver operating characteristic analyses show remarkable concordance between pyruvate's beneficial functional and metabolic effects in isolated, perfused hearts and in patients recovering from cardiopulmonary bypass in which they received pyruvate- vs. L-lactate-fortified cardioplegia. This research exemplifies the translation of mechanism-oriented preclinical studies to clinical application and outcomes.

Multi-institutional analysis of neutrophil-to-lymphocyte ratio (NLR) in patients with severe hemorrhage: A new mortality predictor value

BACKGROUND

The neutrophil/lymphocyte ratio (NLR) has been associated as a predictor for increased mortality in critically ill patients. We sought to determine the relationship between NLR and outcomes in adult trauma patients with severe hemorrhage requiring the initiation of massive transfusion protocol (MTP). We hypothesized that the NLR would be a prognostic indicator of mortality in this population.

METHODS

This was a multi-institutional retrospective cohort study of adult trauma patients (≥18 years) with severe hemorrhage who received MTP between November 2014 and November 2015. Differentiated blood cell counts obtained at days 3 and 10 were used to obtain NLR. Receiver operating characteristic (ROC) curve analysis assessed the predictive capacity of NLR on mortality. To identify the effect of NLR on survival, Kaplan-Meier (KM) survival analysis and Cox regression models were used.

RESULTS

A total of 285 patients with severe hemorrhage managed with MTP were analyzed from six participating institutions. Most (80%) were men, 57.2% suffered blunt trauma. Median (IQR) age, Injury Severity Score, and Glasgow Coma Scale were 35 (25-47), 25 (16-36), and 9 (3-15), respectively. Using ROC curve analysis, optimal NLR cutoff values of 8.81 at day 3 and 13.68 at day 10 were calculated by maximizing the Youden index. KM curves at day 3 (p = 0.05) and day 10 (p = 0.02) revealed an NLR greater than or equal to these cutoff values as a marker for increased in-hospital mortality. Cox regression models failed to demonstrate an NLR over 8.81 as predictive of in-hospital mortality at day 3 (p = 0.056) but was predictive for mortality if NLR was greater than 13.68 at day 10 (p = 0.036).

CONCLUSIONS

NLR is strongly associated with early mortality in patients with severe hemorrhage managed with MTP. Further research is needed to focus on factors that can ameliorate NLR in this patient population.

LEVEL OF EVIDENCE

Prognostic study, level III.

Early structural changes of the heart after experimental polytrauma and hemorrhagic shock

Evidence is emerging that systemic inflammation after trauma drives structural and functional impairment of cardiomyocytes and leads to cardiac dysfunction, thus worsening the outcome of polytrauma patients. This study investigates the structural and molecular changes in heart tissue 4 h after multiple injuries with additional hemorrhagic shock using a clinically relevant rodent model of polytrauma. We determined mediators of systemic inflammation (keratinocyte chemoattractant, macrophage chemotactic protein 1), activated complement component C3a and cardiac troponin I in plasma and assessed histological specimen of the mouse heart via standard histomorphology and immunohistochemistry for cellular and subcellular damage and ongoing apoptosis. Further we investigated spatial and quantitative changes of connexin 43 by immunohistochemistry and western blotting. Our results show significantly increased plasma levels of both keratinocyte chemoattractant and cardiac troponin I 4 h after polytrauma and 2 h after induction of hypovolemia. Although we could not detect any morphological changes, immunohistochemical evaluation showed increased level of tissue high-mobility group box 1, which is both a damage-associated molecule and actively released as a danger response signal. Additionally, there was marked lateralization of the cardiac gap-junction protein connexin 43 following combined polytrauma and hemorrhagic shock. These results demonstrate a molecular manifestation of remote injury of cardiac muscle cells in the early phase after polytrauma and hemorrhagic shock with marked disruption of the cardiac gap junction. This disruption of an important component of the electrical conduction system of the heart may lead to arrhythmia and consequently to cardiac dysfunction.

Systemic inflammatory response syndrome criteria and the prediction of hospital mortality in critically ill patients: a retrospective cohort study

OBJECTIVE

This study intended to determine whether the systemic inflammatory response syndrome criteria can predict hospital mortality in a Brazilian cohort of critically ill patients.

METHODS

We performed a retrospective cohort study at a private tertiary hospital in São Paulo (SP), Brazil. We extracted information from the adult intensive care unit database (Sistema EpimedTM). We compared the SAPS 3 and the systemic inflammatory response syndrome model as dichotomous (≥ 2 criteria: systemic inflammatory response syndrome -positive versus 0 - 1 criterion: systemic inflammatory response syndrome -negative) and ordinal variables from 0 to 4 (according to the number of systemic inflammatory response syndrome criteria met) in the prediction of hospital mortality at intensive care unit admission. Model discrimination was compared using the area under the receiver operating characteristics (AUROC) curve.

RESULTS

From January to December 2012, we studied 932 patients (60.4% were systemic inflammatory response syndrome -positive). systemic inflammatory response syndrome -positive patients were more critically ill than systemic inflammatory response syndrome -negative patients and had higher hospital mortality (16.9% versus 8.1%, p < 0.001). In the adjusted analysis, being systemic inflammatory response syndrome -positive independently increased the risk of death by 82% (odds ratio 1.82; 95% confidence interval [CI] 1.12 - 2.96, p = 0.016). However, the AUROC curve for the SAPS 3 model was higher (0.81, 95%CI 0.78 - 0.85) compared to the systemic inflammatory response syndrome model with the systemic inflammatory response syndrome criteria as a dichotomous variable (0.60, 95%CI 0.55 - 0.65) and as an ordinal variable (0.62, 95%CI 0.57 - 0.68; p < 0.001) for hospital mortality.

CONCLUSION

Although systemic inflammatory response syndrome is associated with hospital mortality, the systemic inflammatory response syndrome criteria show low accuracy in the prediction of mortality compared with the SAPS 3.

Erythropoietin in patients with traumatic brain injury and extracranial injury-A post hoc analysis of the erythropoietin traumatic brain injury trial

BACKGROUND

Erythropoietin (EPO) may reduce mortality after traumatic brain injury (TBI). Secondary brain injury is exacerbated by multiple trauma, and possibly modifiable by EPO. We hypothesized that EPO decreases mortality more in TBI patients with multiple trauma, than in patients with TBI alone.

METHODS

A post hoc analysis of the EPO-TBI randomized controlled trial conducted in 2009 to 2014. To evaluate the impact of injuries outside the brain, we calculated an extracranial Injury Severity Score (ISS) that included the same components of the ISS, excluding head and face components. We defined multiple trauma as two injured body regions with an Abbreviated Injury Scale (AIS) score of 3 or higher. Cox regression analyses, allowing for potential differential responses per the presence or absence of extracranial injury defined by these injury scores, were used to assess the effect of EPO on time to mortality.

RESULTS

Of 603 included patients, the median extracranial ISS was 6 (interquartile range, 1-13) and 258 (43%) had an AIS score of 3 or higher in at least two body regions. On Cox regression, EPO was associated with decreased mortality in patients with greater extracranial ISS (interaction p = 0.048) and weakly associated with differential mortality with multiple trauma (AIS score > 3 or in two regions, interaction p = 0.17). At 6 months in patients with extracranial ISS higher than 6, 10 (6.8%) of 147 EPO-treated patients compared with 26 (17%) of 154 placebo-treated patients died (risk reduction, 10%; 95% confidence interval, 2.9-17%; p = 0.007).

CONCLUSION

In this post hoc analysis, EPO administration was associated with a potential differential improvement in 6-month mortality in TBI patients with more severe extracranial injury. These findings need confirmation in future clinical and experimental studies.

LEVEL OF EVIDENCE

Therapeutic study, level III.

Presenting hypertension, burn injury, and mortality in combat casualties

INTRODUCTION

The effect of presenting hypertension is poorly studied in combat casualties. We hypothesized that elevated mean arterial pressure (MAP) on presentation to combat hospitals would be associated with poor outcomes.

METHODS

Data was obtained from the Department of Defense Trauma Registry and the Armed Forces Medical Examiner System. Variables analyzed included presenting vital signs to Role II-III military theater hospital, demographic variables, injury severity score (ISS), location and mechanism of injury, presence of traumatic brain injury (TBI), acute kidney injury (AKI), and mortality. Patients were stratified by decile of MAP and logistic regression analysis was employed to adjust for confounders.

RESULTS

A total of 4072 subjects injured from February 2002 to February 2011 were identified. Compared to patients in the middle deciles of presenting MAP, patients in the highest and lowest MAP deciles were the only groups that demonstrated a higher mortality on univariate analysis (OR 2.06, 95% CI 1.16-2.31 and OR 2.86, 95% CI 1.76-4.67, respectively), and this relationship persisted after adjustment for ISS, HR, temperature, presence of burn injury, TBI, and AKI. Burn injury was associated with mortality in the full multivariate analysis. However, further analysis limited to patients without burn injury did not demonstrate an association between high MAP and mortality (OR 0.84, 95% CI 0.36-1.99; p=0.70). Conversely, when limited to patients with burn injury, high MAP was associated with mortality (OR 3.78, 95% CI 1.74-8.20; p=0.001).

CONCLUSION

The relationship between mortality and presenting MAP appears to be U-shaped, demonstrating increased mortality in the lowest and highest deciles. However, mortality in the highest MAP decile appears to be limited to casualties with associated burn injury, even after adjustment for TBI, AKI, and ISS, which takes into account the severity of the burn injury. Physicians should recognize that burn patients presenting with an elevated MAP are at an increased risk for poor outcomes.

LEVEL OF EVIDENCE

III.

Building better bone: The weaving of biologic and engineering strategies for managing bone loss

Segmental bone loss remains a challenging clinical problem for orthopaedic trauma surgeons. In addition to the missing bone itself, the local tissues (soft tissue, vascular) are often highly traumatized as well, resulting in a less than ideal environment for bone regeneration. As a result, attempts at limb salvage become a highly expensive endeavor, often requiring multiple operations and necessitating the use of every available strategy (autograft, allograft, bone graft substitution, Masquelet, bone transport, etc.) to achieve bony union. A cost-sensitive, functionally appropriate, and volumetrically adequate engineered substitute would be practice-changing for orthopaedic trauma surgeons and these patients with difficult clinical problems. In tissue engineering and bone regeneration fields, numerous research efforts continue to make progress toward new therapeutic interventions for segmental bone loss, including novel biomaterial development as well as cell-based strategies. Despite an ever-evolving literature base of these new therapeutic and engineered options, there remains a disconnect with the clinical practice, with very few translating into clinical use. A symposium entitled "Building better bone: The weaving of biologic and engineering strategies for managing bone loss," was presented at the 2016 Orthopaedic Research Society Conference to further explore this engineering-clinical disconnect, by surveying basic, translational, and clinical researchers along with orthopaedic surgeons and proposing ideas for pushing the bar forward in the field of segmental bone loss. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1855-1864, 2017.

TNF-α release capacity is suppressed immediately after hemorrhage and resuscitation

PURPOSE

It has been suggested that patients with traumatic insults are resuscitated into a state of an early systemic inflammatory response. We aimed to evaluate the influence of hemorrhagic shock and resuscitation (HSR) upon the inflammatory response capacity assessed by overall TNF-α secretion capacity of the host compared to its release from circulating leukocytes in peripheral circulation.

METHODS

Rats (8/group) subjected to HS (MAP of 30-35 mmHg for 90 min followed by resuscitation over 50 min) were challenged with Lipopolysaccharide (LPS), 1 μg/kg intravenously at the end of resuscitation (HSR-LPS group) or 24 h later (HSR-LPS24 group). Control animals were injected with LPS without bleeding (LPS group). Plasma TNF-α was measured at 90 min after the LPS challenge. In addition, whole blood (WB) was obtained either from healthy controls (CON) immediately after resuscitation (HSR), or at 24 h post-shock (HSR 24). WB was incubated with LPS (100 ng/mL) for 2 h at 37 °C. TNF-α concentration and LPS binding capacity (LBC) was determined.

RESULTS

Compared to LPS group, HSR followed by LPS challenge resulted in suppression of plasma TNF-α in HSR-LPS and HSR-LPS24 groups (1835 ± 478, 273 ± 77, 498 ± 200 pg/mL, respectively). Compared to CON the LPS-induced TNF-α release capacity of circulating leukocytes ex vivo was strongly declined both at the end of resuscitation (HSR) and 24 h later (HSR24) (1012 ± 259, 313 ± 154, 177 ± 63 ng TNF/mL, respectively). The LBC in WB was similar between CON and HSR and only moderately enhanced in HSR24 (57 ± 6, 56 ± 6, 71 ± 5 %, respectively).

CONCLUSION

Our data suggest that the overall inflammatory response capacity is decreased immediately after HSR, persisting up to 24 h, and is independent of LBC.

Update on the role of endothelial cells in trauma

PURPOSE

This review gives an overview of physiological processes, mainly regarding vascular endothelial cells and their important role in hemostasis, information processing, and communication during trauma. An insight is given into molecules and cells involved in the first innate immune response through to the behavior of endothelial cells in developing trauma. The goal of this review is to show the overlap of crucial factors related to the endothelium and the development of trauma.

METHODS

A systemic literature search was performed using Google scholar and PubMed.

RESULTS

The results of the literature search showed that the endothelium, especially the vascular endothelium, is involved in various cellular and subcellular pathways of activation, suppression, and transfer of information. A variety of molecules and cells are orchestrated, subsequently the endothelium gets in contact with a traumatizing event.

CONCLUSION

The endothelium is one of the first barriers that comes into contact with exo- and endogenous trauma-related signals and is a pivotal point in activating subsequent pathways and cascades by transfer of information.

Glutamine metabolism drives succinate accumulation in plasma and the lung during hemorrhagic shock

BACKGROUND

Metabolomic investigations have consistently reported succinate accumulation in plasma after critical injury. Succinate receptors have been identified on numerous tissues, and succinate has been directly implicated in postischemic inflammation, organ dysfunction, platelet activation, and the generation of reactive oxygen species, which may potentiate morbidity and mortality risk to patients. Metabolic flux (heavy-isotope labeling) studies demonstrate that glycolysis is not the primary source of increased plasma succinate during protracted shock. Glutamine is an alternative parent substrate for ATP generation during anaerobic conditions, a biochemical mechanism that ultimately supports cellular survival but produces succinate as a catabolite. We hypothesize that succinate accumulation during hemorrhagic shock is driven by glutaminolysis.

METHODS

Sprague-Dawley rats were subjected to hemorrhagic shock for 45 minutes (shock, n = 8) and compared with normotensive shams (sham, n = 8). At 15 minutes, animals received intravenous injection of C5-N2-glutamine solution (iLG). Blood, brain, heart, lung, and liver tissues were harvested at defined time points. Labeling distribution in samples was determined by ultrahigh-pressure liquid chromatography-mass spectrometry metabolomic analysis. Repeated-measures analysis of variance with Tukey comparison determined significance of relative fold change in metabolite level from baseline.

RESULTS

Hemorrhagic shock instigated succinate accumulation in plasma and lungs tissues (8.5- vs. 1.1-fold increase plasma succinate level from baseline, shock vs. sham, p = 0.001; 3.2-fold higher succinate level in lung tissue, shock vs. sham, p = 0.006). Metabolomic analysis identified labeled glutamine and labeled succinate in plasma (p = 0.002) and lung tissue (p = 0.013), confirming glutamine as the parent substrate. Kinetic analyses in shams showed constant total levels of all metabolites without significant change due to iLG.

CONCLUSION

Glutamine metabolism contributes to increased succinate concentration in plasma during hemorrhagic shock. The glutaminolytic pathway is implicated as a therapeutic target to prevent the contribution of succinate accumulation in plasma and the lung-to-postshock pathogenesis.

Hemostatic Therapy Using Tranexamic Acid and Coagulation Factor Concentrates in a Model of Traumatic Liver Injury

BACKGROUND

The potential clinical benefits of targeted therapy with coagulation factor concentrates (e.g., fibrinogen) and antifibrinolytic agents (e.g., tranexamic acid [TXA]) for the treatment of trauma-induced coagulopathy are increasingly recognized. We hypothesized that human fibrinogen concentrate (FC) and prothrombin complex concentrate (PCC), administered as combined therapy with TXA, would provide additive effects for reducing blood loss in an animal trauma model.

METHODS

Thirty-six pigs were subjected to 2 consecutive blunt liver injuries, resulting in severe hemorrhagic shock and coagulopathy. Intervention comprised saline (control group); TXA (15 mg kg, TXA group); TXA and FC (90 mg kg, TXA-FC); or TXA, FC, and PCC (20 U kg, TXA-FC-PCC). Blood loss, thromboelastometry (ROTEM), measures of thrombin generation, platelet activation, and global coagulation variables were monitored for 4 hours. Tissue sections were examined to determine the occurrence of thromboembolic events.

RESULTS

Total blood loss was similar in the TXA-FC and TXA-FC-PCC groups (mean ± SD: 1012 ± 86 mL and 1037 ± 118 mL, respectively; P = 1.000). These values were both lower (P < 0.001) than the TXA group (1579 ± 306 mL). Blood loss in all 3 intervention groups was lower (P < 0.001) than in the control group (2376 ± 478 mL). After trauma and resuscitation, but before study intervention, plasma fibrinogen levels were severely depleted (median for the whole study population: 66 mg dL; interquartile range: 51-108 mg dL) and clot strength was decreased (EXTEM whole-blood maximum clot firmness [MCF]: 53 ± 5 mm). Compared with controls, TXA inhibited fibrinolysis and stabilized MCF and clotting time. The addition of FC restored and stabilized hemostasis to a greater extent than TXA alone; the addition of PCC had no statistically significant impact on blood loss, clot strength (MCF), or clotting time, but it increased thrombin generation. There were no significant differences among the study groups regarding platelet activation. No thrombi or microthrombi were observed in any group at necropsy.

CONCLUSIONS

The early use of TXA and FC reduced blood loss and improved coagulation measurements in a porcine model of blunt liver injury and hemorrhagic shock. FC, administered in addition to TXA, was highly effective in reducing blood loss. The lack of statistically significant reduction in blood loss when PCC was added to TXA and FC may be attributable to the absence of thrombin generation impairment in this model.

Low HDL levels in sepsis versus trauma patients in intensive care unit

BACKGROUND

The protective cardiovascular effect of high-density lipoproteins (HDLs) is considered to chiefly rely on reverse cholesterol transport from peripheral tissues back to the liver. However, HDL particles display pleiotropic properties, including anti-inflammatory, anti-apoptotic or antioxidant functions. Some studies suggest that HDL concentration decreases during sepsis, and an association was reported between low HDL levels and a poor outcome. Like sepsis, trauma is also associated with a systemic inflammatory response syndrome. However, no study has yet explored changes in lipid profiles during trauma. We sought to compare lipid profiles between sepsis and trauma patients in intensive care unit (ICU). In septic patients, we analyzed the association between lipid profile, severity and prognosis.

METHODS

A prospective, observational, single-centered study was conducted in a surgical ICU. For each patient, total cholesterol, HDL, triglyceride and low-density lipoprotein cholesterol levels were assessed at admission. Short-term prognosis outcome was prospectively assessed.

RESULTS

Seventy-five consecutive patients were admitted (50 sepsis and 25 trauma). There was no difference in SOFA and SAPSII scores between the two groups. Patients with sepsis had lower total cholesterol levels than patients with trauma. Regarding the lipoprotein profile, only HDLs differed significantly between the two groups (median [IQR] = 0.33 mmol/l [0.17-0.78] in sepsis patients versus median [IQR] = 0.99 mmol/l [0.74-1.28] in trauma patients; P < 0.0001). Whereas ICU mortality was not associated with lipid levels in the sepsis group, a significant negative correlation was found between HDL concentration and the length of ICU stay (r = -0.35; P = 0.03) in the group of survivor septic patients at ICU discharge. In addition, poor outcome defined as death or a SOFA score >6 at day 3 was associated with lower HDL levels (median [IQR] = 0.20 mmol/l [0.11-0.41] vs. 0.35 mmol/l [0.19-0.86] in patients with poor outcome versus others; P = 0.03).

CONCLUSIONS

Lipid profile was totally different between sepsis and trauma in ICU patients: HDL levels were low in septic patients, whereas their concentration was not altered in trauma patients. This major difference reinforces the necessity to explore the therapeutic potential of HDL in sepsis.

The role of extracellular histone in organ injury

Histones are intra-nuclear cationic proteins that are present in all eukaryotic cells and are highly conserved across species. Within the nucleus, they provide structural stability to chromatin and regulate gene expression. Histone may be released into the extracellular space in three forms: freely, as a DNA-bound nucleosome or as part of neutrophil extracellular traps, and all three can be detected in serum after significant cellular death such as sepsis, trauma, ischaemia/reperfusion injury and autoimmune disease. Once in the extracellular space, histones act as damage-associated molecular pattern proteins, activating the immune system and causing further cytotoxicity. They interact with Toll-like receptors (TLRs), complement and the phospholipids of cell membranes inducing endothelial and epithelial cytotoxicity, TLR2/TLR4/TLR9 activation and pro-inflammatory cytokine/chemokine release via MyD88, NFκB and NLRP3 inflammasome-dependent pathways. Drugs that block the release of histone, neutralise circulating histone or block histone signal transduction provide significant protection from mortality in animal models of acute organ injury but warrant further research to inform future clinical applications.

Induced hypothermia is associated with reduced circulating subunits of mitochondrial DNA in cardiac arrest patients

Induced hypothermia may protect from ischemia reperfusion injury. The mechanism of protection is not fully understood and may include an effect on mitochondria. Here we describe the effect of hypothermia on circulating mitochondrial (mt) DNA in a substudy of a multicenter randomized trial (the Target Temperature Management trial). Circulating levels of mtDNA were elevated in patients with cardiac arrest at all-time points compared to healthy controls. After 24 h of temperature management, patients kept at 33 °C had significantly lower levels of COX3, NADH1 and NADH2 compared to baseline, in contrast to those kept at 36 °C. After regain of temperature, cytochrome - B was significantly reduced in patients kept at 33 °C with cardiac arrest. Cardiac arrest results in circulating mtDNA levels, which reduced during a temperature management protocol in patients with a target temperature of 33 °C.

The Effect of Surgical Stress on Postoperative Tαβ and Tγδ Cell Distribution

BACKGROUND

It was previously shown that appropriate distribution of immune cells between different tissues and organs of the body is required for proper function of the immune system. Our previous experiments demonstrated that surgical trauma in mice induces Tγδ lymphocyte migration from peripheral blood to peritoneal lymphoid organs. Tγδ cells have regulatory activity as they suppress the cell-mediated immune response in vitro via TGF-β. In the current study, we aim to evaluate the influence of surgery on both Taβ and Tγδ lymphocyte distribution in patients that underwent operation.

MATERIALS AND METHODS

We investigated the percentage of Tαβ and Tγδ cells in peripheral blood of patients undergoing standard surgical procedures (gastric resection, colorectal resection, cholecystectomy, and strumectomy) before and 3 days after operation. The percentage of Tαβ and Tγδ cells was evaluated by FACS Canto II cytofluorimeter.

RESULTS

We showed that only major surgery located in the peritoneal cavity (gastric and colorectal surgery) decreases the percentage of Tγδ cells in peripheral blood as opposed to less traumatic surgery (strumectomy and cholecystectomy) which does not have such effect. However, significant reduction of Tγδ cells after operation was only observed in a group of patients that underwent gastrectomy. Additionally, we found that gastrectomy results in significant reduction of cumulative Tγδ CD4 and Tγδ CD25 lymphocyte counts.

CONCLUSION

Surgery results in decreased percentage of Tγδ lymphocytes in peripheral human blood, and this correlates with the severity and location of the surgical trauma. This observation may help to predict postoperative recovery after gastroabdominal surgery.

Length of hospitalization is associated with selected biomarkers (albumin and lymphocytes) and with co-morbidities: study on 4000 patients

Background

Low albumin levels and low lymphocyte counts are intra hospital conditions that exert a negative influence on prognosis, healing and length of hospitalization. The study aimed to analyze the correlation between low blood levels of albumin, low lymphocytes, and length of stay. The secondary aim was to identify other co-morbidities associated with prolonged hospital stay.

Methods

Retrospective pilot study was conducted by analyzing anamnestic and biochemical data, related to 4038 patients admitted to ten wards of Hospital San Paolo (Milan), collected from July 1^st 2012 to December 31^st 2012. A statistical analysis was carried out using the Correlation method, Multivariate Analysis and Regression. Lymphocyte count and co-morbidities were evaluated in the whole cohort, albumin levels in 1437 patients.

Results

In the whole sample, low albumin levels and low lymphocyte counts were directly correlated to longer hospitalizations. The stratification of the results by department and diagnosis suggests that there is a higher correlation in certain subpopulations, and albumin shows a greater correlation with length of stay than lymphocytes. Also advanced age, high platelets, type of diagnosis, male gender and emergency admission led to longer hospitalizations.

Conclusions

A routine check of albumin, lymphocytes and a spectrum of significant variables can provide precious information which can eventually lead to a shorter hospital stay. Knowledge of the general health status of a patient and the possibility to estimate his/her length of hospital stay are essential information for Clinical Governance, and for the improvement of internal services of hospitals on a large scale.

PDGF is a potent initiator of bone formation in a tissue engineered model of pathological ossification

Heterotopic ossification (HO) is a debilitating condition defined by the rapid formation of bone in soft tissues. What makes HO fascinating is first the rate at which bone is deposited, and second the fact that this bone is structurally and compositionally similar to that of a healthy adult. If the mechanisms governing HO are understood, they have the potential to be exploited for the development of potent osteoinductive therapies. With this aim, a tissue‐engineered skeletal muscle was used model to better understand the role of inflammation on this debilitating phenomenon. It was shown that myoblasts could be divided into two distinct populations: myogenic cells and undifferentiated ‘reserve’ cells. Gene expression analysis of myogenic and osteoregulatory markers confirmed that ‘reserve’ cells were primed for osteogenic differentiation but had a reduced capacity for myogenesis. Osteogenic differentiation was significantly enhanced in the presence of platelet‐derived growth factor (PDGF)‐BB and bone morphogenetic protein 2 (BMP2), and correlated with conversion to a Sca‐1⁺/CD73⁺ phenotype. Alizarin red staining showed that PDGF‐BB promoted significantly more mineral deposition than BMP2. Finally, it was shown that PDGF‐induced mineralization was blocked in the presence of the pro‐inflammatory cytokines tumour necrosis factor‐α and interleukin 1. In conclusion, the present study identified that PDGF‐BB is a potent osteoinductive factor in a model of tissue‐engineered skeletal muscle, and that the osteogenic capacity of this protein was modulated in the presence of pro‐inflammatory cytokines. These findings reveal a possible mechanism by which HO develops following trauma. Importantly, these findings have implications for the induction and control of bone formation for regenerative medicine. © 2016 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd.

Mesenchymal stem cells increase expression of heme oxygenase-1 leading to anti-inflammatory activity in treatment of acute liver failure

BACKGROUND

Mesenchymal stem cells (MSCs) have been studied for the treatment of acute liver failure (ALF) for several years. MSCs may exert their effect via complex paracrine mechanisms. Heme oxygenase (HO) 1, a rate-limiting enzyme in heme metabolism, exerts a wide range of anti-inflammatory, anti-apoptotic and immunoregulatory effects in a variety of diseases. However, the relationship between MSCs and HO-1 in the treatment of ALF is still unclear. We investigated the preventive and therapeutic potential of intravenously administered BMSCs.

METHODS

Bone marrow-derived mesenchymal stem cells (BMSCs) obtained from Sprague-Dawley rats were isolated and cultured. We employed BMSCs, hemin (a HO-1 inducer) and zinc protoporphyrin (ZnPP, the HO-1 activity inhibitor) in D-galactosamine (D-Gal)/lipopolysaccharides (LPS)-induced ALF rats. Rats were sacrificed at days 1, 3, 5, and 7 post-transfusion, respectively. Blood samples and liver tissues were collected. Hepatic injury, HO-1 activity, chemokines, inflammatory cytokines, the number and oxidative activity of neutrophils, ki67, and TUNEL-positive cells were evaluated.

RESULTS

HO-1 induction or BMSCs transplantation attenuated D-galactosamine/lipopolysaccharide-induced increases in alanine aminotransferase, aspartate aminotransferase, total bilirubin (TBIL), ammonia, and inflammatory cytokines. Treatment with hemin or BMSCs also inhibited neutrophil infiltration, oxidative activity, and hepatocyte apoptosis. The protective effect of BMSCs was partially neutralized by ZnPP, suggesting the key role of HO-1 in the process.

CONCLUSIONS

These findings may correlate with inhibition of nuclear factor-κ B activation. BMSCs ameliorated ALF by increasing the HO-1 expression, which reduced PMN infiltration and function, and played an important anti-inflammatory and anti-apoptotic role. Proposed mechanism by which BMSCs reduce inflammation, neutrophil activation, and hepatocyte apoptosis and promote hepatocyte proliferation via HO-1. BMSCs increase HO-1 expression in liver via Nrf2. HO-1 protects against LPS/D-Gal-induced ALF by inhibiting neutrophil infiltration and inflammatory burst, and hepatocyte apoptosis and necrosis. HO-1 also promotes hepatocyte proliferation.

Postoperative Infections are Associated with Increased Risk of Cardiac Events in Vascular Patients

BACKGROUND

Despite advances in perioperative care, the rate of cardiac events in vascular patients remains high. We have previously shown that infections in trauma patients are associated with higher rates of subsequent cardiac complications, likely due to the additive effect of a second hit of an infection following the trauma. The aim of this study was to investigate whether there is an association between postoperative infections and subsequent cardiac events in vascular patients.

METHODS

A 5-year retrospective review of demographics, comorbidities, operative interventions, infectious, and cardiac events in all vascular patients who underwent an operative intervention at a single tertiary referral center was performed. In patients with clinical suspicion of myocardial injury, myocardial damage was defined as troponin >0.15 ng/mL and myocardial infarction (MI) as troponin >1 ng/mL. Pneumonia was diagnosed using bronchoalveolar lavage (BAL) and considered positive if BAL fluid culture contained >10,000 colony-forming units (cfu). Urinary tract infection (UTI) was diagnosed if the urine culture contained >100,000 cfu. All other infections were diagnosed by culture data. Regression analysis was performed to assess risk of cardiac events as a function of infections adjusting for age, gender, and comorbidities.

RESULTS

We analyzed 1,835 vascular operative interventions with the mean age of the cohort 65.5 years (65.9% male). The overall infection rate was 13.2%, with UTI being the most common (60.3%). The overall rate of myocardial damage was 8.1% and the rate of MI 3.8%. Rates of both myocardial damage (15.5 vs. 7.7%; P = 0.0015) and MI (7.1 vs. 3.4%; P = 0.018) were significantly higher in patients with infections, compared to those without infections. Adjusting for age, gender, medical comorbidities, open versus endovascular cases as well as statin and steroid use, patients with UTI were more likely to subsequently develop either myocardial damage (odds ratio [OR] = 3.57 [95% confidence interval = 1.51-8.45]) or MI (OR = 4.20 [1.23-14.3]). A similar association was noted between any infections and either myocardial damage (OR = 2.97 [1.32-6.65]) or MI (OR = 4.31 [1.44-12.94]).

CONCLUSIONS

We herein describe an association between postoperative infections, most commonly UTI, and subsequent cardiac events. Efforts should be made to minimize the risk of developing infections to ensure cardioprotection in vascular patients during perioperative period.

Heart Rate Variability for the Early Detection of Delayed Cerebral Ischemia

Delayed cerebral ischemia is considered the leading cause of death or major disability in subarachnoid hemorrhage after the impact of the initial event and rebleeding. Waiting to treat patients until they exhibit clinical symptoms of ischemia is too late to prevent cerebral infarction for more than 60% of patients, and transcranial Doppler ultrasonography has not proven to be a reliable screening tool to identify high-risk patients. Continuous heart rate variability monitoring may provide an alternative screening strategy to identify patients at high risk for delayed cerebral ischemia. Heart rate variability is a composite reflection of autonomic outflow, neuroendocrine influences, and autonomic responsiveness. Most importantly, heart rate variability is responsive to changes in systemic inflammation, which evidence suggests is important to the causal pathway of delayed cerebral ischemia. The clinical application of continuous heart rate variability monitoring in critical care is relatively recent despite its existence for more than 50 years. Initial studies suggest promise for heart rate variability monitoring as a delayed cerebral ischemia screening tool, but significant research is still required before this approach may achieve clinical applicability and bring benefit to patients.

Effect of disrupted mitochondria as a source of damage-associated molecular patterns on the production of tumor necrosis factor α by splenocytes from dogs

OBJECTIVE To evaluate the effects of damage-associated molecular patterns (DAMPs) derived from disrupted mitochondria on canine splenocytes and other immune cells. SAMPLES Liver, spleen, and bone marrow samples obtained from 8 cadavers of healthy research Beagles that had been euthanized for other purposes. PROCEDURES Mitochondria were obtained from canine hepatocytes, and mitochondrial DAMPs (containing approx 75% mitochondrial proteins) were prepared. Mitochondrial DAMPs and the nuclear cytokine high-mobility group box protein 1 were applied to splenocytes, bone marrow-differentiated dendritic cells, and a canine myelomonocytic cell (DH82) line for 6 or 24 hours. Cell culture supernatants from splenocytes, dendritic cells, and DH82 cells were assayed for tumor necrosis factor α with an ELISA. Expression of tumor necrosis factor α mRNA in splenocytes was evaluated with a quantitative real-time PCR assay. RESULTS In all cell populations evaluated, production of tumor necrosis factor α was consistently increased by mitochondrial DAMPs at 6 hours (as measured by an ELISA). In contrast, high-mobility group box protein 1 did not have any independent proinflammatory effects in this experimental system. CONCLUSIONS AND CLINICAL RELEVANCE The study revealed an in vitro inflammatory effect of mitochondrial DAMPs (containing approx 75% mitochondrial proteins) in canine cells and validated the use of an in vitro splenocyte model to assess DAMP-induced inflammation in dogs. This experimental system may aid in understanding the contribution of DAMPs to sepsis and the systemic inflammatory response syndrome in humans. Further studies in dogs are needed to validate the biological importance of these findings and to evaluate the in vivo role of mitochondrial DAMPs in triggering and perpetuating systemic inflammatory states.

Low concentration of uncouplers of oxidative phosphorylation decreases the TNF-induced endothelial permeability and lethality in mice

Mitochondrial dysfunctions occur in many diseases linked to the systemic inflammatory response syndrome (SIRS). Mild uncoupling of oxidative phosphorylation is known to rescue model animals from pathologies related to mitochondrial dysfunctions and overproduction of reactive oxygen species (ROS). To study the potential of SIRS therapy by uncoupling, we tested protonophore dinitrophenol (DNP) and a free fatty acid (FFA) anion carrier, lipophilic cation dodecyltriphenylphosphonium (C₁₂TPP) in mice and in vitro models of SIRS. DNP and C₁₂TPP prevented the body temperature drop and lethality in mice injected with high doses of a SIRS inducer, tumor necrosis factor (TNF). The mitochondria-targeted antioxidant plastoquinonyl decyltriphenylphosphonium (SkQ1) which also catalyzes FFA-dependent uncoupling revealed similar protective effects and downregulated expression of the NFκB-regulated genes (VCAM1, ICAM1, MCP1, and IL-6) involved in the inflammatory response of endothelium in aortas of the TNF-treated mice. In vitro mild uncoupling rescued from TNF-induced endothelial permeability, disassembly of cell contacts and VE-cadherin cleavage by the matrix metalloprotease 9 (ММР9). The uncouplers prevented TNF-induced expression of MMP9 via inhibition of NFκB signaling. Water-soluble antioxidant Trolox also prevented TNF-induced activation and permeability of endothelium in vitro via inhibition of NFκB signaling, suggesting that the protective action of the uncouplers is linked to their antioxidant potential.

Similar change in platelets and leucocytes 24 h after injury is associated with septic shock a week later

BACKGROUND

Septic shock is a severe complication in polytrauma patients. Early identification of patients at risk can guide future prevention strategies. Platelets (PLTs) and leucocytes presumably play an important role in the post-injury inflammatory response. The role of early changes in PLT and leucocyte counts was investigated in search for the aetiology of the development of septic complications.

METHODS

Polytrauma patients (aged 16-80 years) admitted to the intensive care unit with an expected stay of at least 3 days were included. PLT and leucocyte counts were measured on a daily basis for 14 days.

RESULTS

A total of 41 patients were included, of whom nine (22%) developed septic shock. There was no difference in (New) Injury Severity Score or Acute Physiology and Chronic Health Evaluation II scores between patients who developed septic shock and patients who did not. Three patients died, one of them in septic shock. Patients who developed septic shock during hospital stay had lower PLTs and a slower recovery to normal PLT counts than patients without septic shock. Patients who developed either a decrease in both PLTs and leucocytes or an increase in PLTs and leucocytes in the first 24 h after trauma were more likely to develop septic shock. This correlation was not found in patients who did not develop septic shock.

CONCLUSION

A similar change in PLT and leucocyte counts in the first 24 h after trauma is associated with the development of septic shock after a week. This indicates an early interaction between PLTs and leucocytes, which needs further investigation to gain more insight in the aetiology of post-injury septic complications.

OXYGEN MITIGATES THE INFLAMMATORY RESPONSE IN A MODEL OF HEMORRHAGE AND ZYMOSAN-INDUCED INFLAMMATION

Sequential insults (hits) may change the inflammatory reaction that develops in response to separate single hits (e.g., injury, infection); however, their effects on the long-term clinical outcome are still only partially elucidated. Double-hit models are typically severe and fatal. We characterized in C57BL/6 mice a moderate double-hit model of hemorrhage (35%-40% of total blood volume) and resuscitation, followed by peritoneal injection of zymosan A that induced local and systemic inflammation with 58% mortality. This model allowed exploration of the inflammatory response over time in the surviving mice. We show that after 2 days, mice subjected to the double-hit model had elevated proinflammatory systemic and local peritoneal cytokine response (interleukin [IL]-1β, tumor necrosis factor-α, IL-6) and moderately elevated anti-inflammatory cytokines (IL-10, transforming growth factor-β), compared with the single-hit and sham mice. However, this dynamically changed, and by day 7, proinflammatory cytokines were reduced, and anti-inflammatory cytokines were markedly (P < 0.05) elevated in the double-hit group. Mice in the double-hit group that inhaled 100% oxygen intermittently for 6 h every day exhibited markedly reduced serum proinflammatory cytokines as early as day 2 (P < 0.05), inhibited macrophage infiltration into the peritoneum (by 13-fold; P < 0.05), and substantially increased survival rates of 85% (P = 0.00144). Oxygen mitigates the inflammatory response and exerts a beneficial effect on survival in a double-hit model of hemorrhage and zymosan-induced inflammation.

Platelets modulate the immune response following trauma by interaction with CD4+ T regulatory cells in a mouse model

CD4+ T regulatory cells (Tregs) play a pivotal role in the anti-inflammatory immune response following trauma. The mechanisms of CD4+ Treg activation are mostly unknown. Here, we hypothesize that platelets regulate CD4+ Treg activation following trauma. In a murine burn injury model (male C57Bl/6N mice), depletion of platelets or CD4+ Tregs was conducted. Draining lymph nodes, blood and spleen were harvested 2 h and 7 days after trauma. CD4+ Treg activation was measured using phospho- and conventional flow cytometry. Platelet activation was analyzed using thromboelastometry and flow cytometry. Trauma differentially activates CD4+ T cells, early after trauma only CD4+ Tregs are activated. Following burn injury, platelets augment the activation of CD4+ Tregs. This effect could only be seen early after trauma. While CD4+ Tregs influence hemostasis early following trauma, platelet activation markers were unchanged. Beyond their role in hemostasis, platelets are able to modulate the immunologic host response to trauma-induced injury by augmenting the activation of CD4+ Tregs. CD4+ Treg activation following trauma is considered protective. In addition, CD4+ Tregs are capable of modulating the hemostatic function of platelets. For the first time, we could show reciprocal activation of platelets and CD4+ Tregs as part of the protective immune response following trauma.