Release of anti-inflammatory mediators after mechanical trauma correlates with severity of injury and clinical outcome

The local and systemic effects of immune function on fracture healing

The immune system plays an integral role in the regulation of cellular processes responsible for fracture healing. Local and systemic influences on fracture healing correlate in many ways with fracture-related outcomes, including soft tissue healing quality and fracture union rates. Impaired soft tissue healing, restricted perfusion of a fracture site, and infection also in turn affect the immune response to fracture injury. Modern techniques used to investigate the relationship between immune system function and fracture healing include precision medicine, using vast quantities of data to interpret broad patterns of inflammatory response. Early data from the PRECISE trial have demonstrated distinct patterns of inflammatory response in polytrauma patients, which thereby directly and indirectly regulate the fracture healing response. The clearly demonstrated linkage between immune function and fracture healing suggests that modulation of immune function has significant potential as a therapeutic target that can be used to enhance fracture healing.

Brain Plasticity Modulator p75 Neurotrophin Receptor in Human Urine after Different Acute Brain Injuries-A Prospective Cohort Study

Acute brain injuries (ABIs) pose a substantial global burden, demanding effective prognostic indicators for outcomes. This study explores the potential of urinary p75 neurotrophin receptor (p75NTR) concentration as a prognostic biomarker, particularly in relation to unfavorable outcomes. The study involved 46 ABI patients, comprising sub-cohorts of aneurysmal subarachnoid hemorrhage, ischemic stroke, and traumatic brain injury. Furthermore, we had four healthy controls. Samples were systematically collected from patients treated at the University Hospital of Turku between 2017 and 2019, at early (1.50 ± 0.70 days) and late (9.17 ± 3.40 days) post-admission time points. Urinary p75NTR levels, measured by ELISA and normalized to creatinine, were compared against patients' outcomes using the modified Rankin Scale (mRS). Early urine samples showed no significant p75NTR concentration difference between favorable and unfavorable mRS groups. In contrast, late samples exhibited a statistically significant increase in p75NTR concentrations in the unfavorable group (p = 0.033), demonstrating good prognostic accuracy (AUC = 70.9%, 95% CI = 53-89%, p = 0.03). Assessment of p75NTR concentration changes over time revealed no significant variation in the favorable group (p = 0.992) but a significant increase in the unfavorable group (p = 0.009). Moreover, p75NTR concentration was significantly higher in ABI patients (mean ± SD 40.49 ± 28.83-65.85 ± 35.04 ng/mg) compared to healthy controls (mean ± SD 0.54 ± 0.44 ng/mg), irrespective of sampling time or outcome (p < 0.0001). In conclusion, late urinary p75NTR concentrations emerged as a potential prognostic biomarker for ABIs, showing increased levels associated with unfavorable outcomes regardless of the specific type of brain injury. While early samples exhibited no significant differences, the observed late increases emphasize the time-dependent nature of this potential biomarker. Further validation in larger patient cohorts is crucial, highlighting the need for additional research to establish p75NTR as a reliable prognostic biomarker across various ABIs. Additionally, its potential role as a diagnostic biomarker warrants exploration.

Characteristics of inflammatory response and repair after experimental blast lung injury in rats

BACKGROUND AND OBJECTIVES

Blast-induced lung injury is associated with inflammatory, which are characterised by disruption of the alveolar-capillary barrier, haemorrhage, pulmonary infiltrateration causing oedema formation, pro-inflammatory cytokine and chemokine release, and anti-inflammatory counter-regulation. The objective of the current study was to define sequence of such alterations in with establishing blast-induced lung injury in rats using an advanced blast generator.

METHODS

Rats underwent a standardized blast wave trauma and were euthanised at defined time points. Non-traumatised animals served as sham controls. Obtained samples from bronchoalveolar lavage fluid (BALF) at each time-point were assessed for histology, leukocyte infiltration and cytokine/chemokine profile.

RESULTS

After blast lung injury, significant haemorrhage and neutrophil infiltration were observed. Similarly, protein accumulation, lactate dehydrogenase activity (LDH), alveolar eicosanoid release, matrix metalloproteinase (MMP)-2 and -9, pro-Inflammatory cytokines, including tumour necrosis factor (TNF) and interleukin (IL) -6 raised up. While declining in the level of anti-inflammatory cytokine IL-10 occurred. Ultimately, pulmonary oedema developed that increased to its maximum level within the first 1.5 h, then recovered within 24 h.

CONCLUSION

Using a stablished model, can facilitate the study of inflammatory response to blast lung injury. Following the blast injury, alteration in cytokine/chemokine profile and activity of cells in the alveolar space occurs, which eventuates in alveolar epithelial barrier dysfunction and oedema formation. Most of these parameters exhibit time-dependent return to their basal status that is an indication to resilience of lungs to blast-induced lung injury.

Biomarkers of endothelial cell dysfunction persist beyond resuscitation in patients with hemorrhagic shock

BACKGROUND

It has been shown that microRNA-19b (miR-19b) binds to and degrades syndecan-1 after hemorrhagic shock (HS) and contributes to endothelial dysfunction in vitro and in vivo. The objective of the current study was to assess longitudinal changes in miR-19b and syndecan-1 in HS patients.

METHODS

Blood samples from HS patients (blood pressure <90 mm Hg and ≥2 U blood) were collected upon admission, completion of hemostasis, and after 24 hours for miR-19b (quantitative reverse transcription PCR) and syndecan-1 (enzyme-linked immunosorbent assay) and compared with controls and minimally injured (Injury Severity Score, ≤9). Inflammatory cytokines were measured (Luminex [Thermo Fisher, Waltham, MA]). Correlations between syndecan-1, miR-19b, inflammatory markers, and patient outcomes were performed. Logistic regression models were developed for outcomes.

RESULTS

Thirty-four HS patients were studied: age, 46 (19-89) years; male, 82%; penetrating, 35%; Injury Severity Score, 24 ± 10; and blood products at 24 hours, 21 ± 19 U. MicroRNA-19b was increased upon arrival and further increased over time: 4.6 → 6.7 → 24.1-fold change compared with 0.1 and 1.2 for minimally injured patients and controls, respectively. Syndecan-1 was increased to 42.6 → 50 → 51.5 ng/mL over time compared with 14.7 and 23.5 for minimally injured and controls, respectively. Values for both biomarkers remained significantly increased through 24 hours and were associated with a persistent increase in inflammatory cytokines. Admission syndecan-1 significantly predicted mortality, coagulopathy, and massive transfusion.

CONCLUSION

We have shown for the first time that miR-19b and syndecan-1 were biomarkers for endothelial dysfunction independent of resuscitation. MicroRNA-19b did not demonstrate a strong correlation with syndecan-1 nor outcomes. Admission syndecan-1, however, remains a strong prognostic marker, but its elevation over time suggests a versatile role following HS that requires further investigation.

LEVEL OF EVIDENCE

Prognostic/Epidemiological; Level II.

Use of recombinant interleukin-2 in traumatic disease in veterinary medicine

Тhe article presents analysis of current information on the possibility of using recombinant interleukin-2 in traumatic disease in veterinary medicine. The analysis included publications from the following databases - P ubMed, MedLine, BIOSIS, ToxiNet, CANCERLIT, CINAHL, CISCOM, EMBASE, International Pharmaceutical Abstracts, and NAPRALERT, using 10 keywords and their combinations. It was shown that in trauma of any genesis, an immunodeficiency state occurs associated with an imbalance of Th1/Th2 cytokines. The use of recombinant interleukin-2 restores synthesis of endogenous interleukin-2, provides adequate targeted drug correction of immune dysfunctions, increasing the clinical and immunological effectiveness of therapeutic measures.

Evaluating TNF-α and Interleukin-2 (IL-2) Levels in African American Primary Open-Angle Glaucoma Patients

Purpose: To establish if SNPs in TNF-α and IL-2 genes are associated with Primary Open-Angle Glaucoma (POAG) in African Americans (AA). We also determined whether plasma TNF-α and IL-2 levels could serve as biomarkers for POAG in African Americans using sandwich enzyme-linked immunosorbent assay. Methods: A single SNP association analysis was performed to investigate the association between potential gene variants in TNF-α and IL-2 genes and POAG in the AA population. Plasma samples from 190 African Americans (72 from normal subjects and 118 POAG cases) were obtained for TNF- α studies and 367 samples (135 from normal subjects and 232 from POAG cases) were obtained for IL-2 studies. TNF-α levels and IL-2 levels were measured by sandwich enzyme-linked immunosorbent assays (ELISA) and analyzed to see if they reached significance in cases with POAG and endophenotypes when compared to normal subjects. Results: The SNP, rs1800630, in TNF-α gene was found to be marginally associated with POAG. SNPs in IL-2 gene were not associated with POAG in the case-control analysis. No significant difference was found between TNF-α levels and IL-2 levels in normal and POAG case subjects in our study. IL-2 levels were inversely correlated with high IOP in POAG cases. Conclusions: Although we found a marginal SNP association of TNF-α, assessing the expression levels of TNF-α and IL-2 may serve as promising biomarkers for African American POAG. Further investigation is needed to determine if POAG can be subdivided into more specified cohorts of the disease, which may affect plasma cytokine levels differently.

Computational evidence for an early, amplified systemic inflammation program in polytrauma patients with severe extremity injuries

Extremity and soft tissue injuries contribute significantly to inflammation and adverse in-hospital outcomes for trauma survivors; accordingly, we examined the complex association between clinical outcomes inflammatory responses in this setting using in silico tools. Two stringently propensity-matched, moderately/severely injured (Injury Severity Score > 16) patient sub-cohorts of ~30 patients each were derived retrospectively from a cohort of 472 blunt trauma survivors and segregated based on their degree of extremity injury severity (above or below 3 on the Abbreviated Injury Scale). Serial blood samples were analyzed for 31 plasma inflammatory mediators. In addition to standard statistical analyses, Dynamic Network Analysis (DyNA) and Principal Component Analysis (PCA) were used to model systemic inflammation following trauma. Patients in the severe extremity injury sub-cohort experienced longer intensive care unit length of stay (LOS), total LOS, and days on a mechanical ventilator, with higher Marshall Multiple Organ Dysfunction (MOD) Scores over the first 7 days post-injury as compared to the mild/moderate extremity injury sub-cohort. The higher severity cohort had statistically significant elevated lactate, base deficit, and creatine phosphokinase on first blood draw, along with significant changes in multiple circulating inflammatory mediators. DyNA pointed to a sustained role for type 17 immunity in both sub-cohorts, along with IFN-γ in the severe extremity injury group. DyNA network complexity increased over 7 days post-injury in the severe injury group, while generally decreasing over this same time period in the mild/moderate injury group. PCA suggested a more robust activation of multiple pathways in the severe extremity injury group as compared to the mild/moderate injury group. These studies thus point to the possibility of self-sustaining inflammation following severe extremity injury vs. resolving inflammation following less severe extremity injury.

Perioperative Mortality Prediction Using Possum in Patients with Gastrointestinal Tumors: Do Immunological Variables Affect Individual Predictive Mortality Risk?

The aim of this study was to evaluate whether the addition of immunological variables to the Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity (POSSUM) scoring system improves the predictability of postoperative mortality. One hundred and thirty-two consecutive patients who underwent moderate, major or major-plus elective surgical interventions for gastrointestinal tumors were scored using the POSSUM mortality risk analysis. Patients were placed in one of the two groups based on their POSSUM mortality rates which were either lower or higher than 5%. An additional 26 pre-operative and post-operative metabolic and immunological variables were measured and mortality-dependent variables were selected. Regression analysis with backward elimination of twelve pre-operative and post-operative variables correlating with POSSUM score revealed that post-operative neopterin, IL-6 and albumin were significantly dependent on the predicted mortality rates. According to these selected variables, the number of patients with a POSSUM predicted mortality rate higher than 5% increased from 64 to 88, but the percentage of the mean mortality decreased. Statistical differences between the original POSSUM and modified scoring system was highly significant (p<0.0001). The sensitivity and specificity of the modified scoring system was calculated to be 52.9% and 87.5%, respectively.

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.

Incidence and predictive risk factors of postoperative sepsis in orthopedic trauma patients

Background

Postoperative sepsis is associated with high mortality and the national costs of septicemia exceed those of any other diagnosis. While numerous studies in the basic orthopedic science literature suggest that traumatic injuries facilitate the development of sepsis, it is currently unclear whether orthopedic trauma patients are at increased risk. The purpose of this study was thus to assess the incidence of sepsis and determine the risk factors that significantly predicted septicemia following orthopedic trauma surgery.

Materials and methods

56,336 orthopedic trauma patients treated between 2006 and 2013 were identified in the ACS-NSQIP database. Documentation of postoperative sepsis/septic shock, demographics, surgical variables, and preoperative comorbidities was collected. Chi-squared analyses were used to assess differences in the rates of sepsis between trauma and nontrauma groups. Binary multivariable regressions identified risk factors that significantly predicted the development of postoperative septicemia in orthopedic trauma patients.

Results

There was a significant difference in the overall rates of both sepsis and septic shock between orthopedic trauma (1.6%) and nontrauma (0.5%) patients (p < 0.001). For orthopedic trauma patients, ventilator use (OR = 15.1, p = 0.002), history of pain at rest (OR = 2.8, p = 0.036), and prior sepsis (OR = 2.6, p < 0.001) were significantly associated with septicemia. Statistically predictive, modifiable comorbidities included hypertension (OR = 2.1, p = 0.003) and the use of corticosteroids (OR = 2.1, p = 0.016).

Conclusions

There is a significantly greater incidence of postoperative sepsis in the trauma cohort. Clinicians should be aware of these predictive characteristics, may seek to counsel at-risk patients, and should consider addressing modifiable risk factors such as hypertension and corticosteroid use preoperatively.

Level of evidence Level III.

Interferon-γ counteracts reduced endotoxin responsiveness of whole blood following trauma and cardiopulmonary bypass

Accidental as well as surgical trauma has been reported to cause reduced endotoxin responsiveness of blood in terms of cytokine production. In this study, the effect of interferon-γ (IFN-γ) on tumour necrosis factor-α (TNF-α)-producing capacity of whole blood after severe trauma and cardiac surgery was investigated. Blood samples of severely injured patients were collected at the first day after trauma and of cardiac surgery patients before, 4 h and 2 days after cardiopulmonary bypass (CPB). The blood samples were incubated with INF-γ (0—100 U/ml) for 20 h and subsequently lipopolysaccharide (LPS)-induced TNF-α production was determined. Compared to healthy donors, LPS-induced TNF-α production was significantly reduced in blood cultures of trauma patients on day 1 after trauma and 4 h after CPB. Pre-incubation with IFN-γ in vitro increased endotoxin-induced TNF-α production in volunteers' and all patients' blood specimens in a dose-dependent manner. IFN-γ prompted an elevation of cytokine synthesis in CPB patients' blood which equalled that of volunteers, whereas it caused a lower rise in TNF-α production in blood of multiply injured patients, reaching levels of untreated donors only after incubation with 100 U/ml IFN-γ. These experiments show that hyporesponsiveness of whole blood induced by trauma or cardiac surgery with CPB is not irreversible, but can be counteracted by the immunostimulant IFN-γ. IFN-γ, therefore, could be applied clinically in trauma patients or after cardiac surgery to prevent or to resolve infection complications.

Association Between MC-2 Peptide and Hepatic Perfusion and Liver Injury Following Resuscitated Hemorrhagic Shock

IMPORTANCE

Hemorrhagic shock (HS) due to trauma remains a major cause of morbidity and mortality in the United States, despite continuing progression of advanced life support and treatment. Trauma is the third most common cause of death worldwide and is the leading cause of death in the 1- to 44-year-old age group. Hemorrhagic shock often progresses to multiple organ failure despite conventional resuscitation (CR) that restores central hemodynamics.

OBJECTIVE

To examine whether MC-2 would bind glycosaminoglycans to decrease proinflammatory cytokines' influence in the liver, minimize organ edema, prevent liver injury, and improve hepatic perfusion. MC-2, a synthetic octapeptide derived from the heparin-binding domain of murine interferon gamma (IFN-γ), binds glycosaminoglycans to modulate serum and interstitial cytokine levels and activity.

DESIGN, SETTING, AND PARTICIPANTS

A controlled laboratory study of 3y male Sprague-Dawley rats that were randomized to 4 groups of 8 each: sham, sham+MC-2 (50 mg/kg), HS/CR, or HS/CR+MC-2 (HS = 40% of baseline mean arterial pressure for 60 minutes; CR = return of shed blood and 2 volumes of saline). The study began in March, 2013.

MAIN OUTCOMES AND MEASURES

Effective hepatic blood flow (EHBF) by galactose clearance, wet-dry weights, cytokines, histopathology, complete metabolic panel, and complete blood cell count were performed at 4 hours after CR.

RESULTS

MC-2 partially reversed the HS/CR-induced hepatic hypoperfusion at 3 and 4 hours postresuscitation compared with HS/CR alone. Effective hepatic blood flow decreased during the HS period from a mean (SD) of 7.4 (0.3) mL/min/100 g and 7.5 (0.5) mL/min/100g at baseline to 3.7 (0.4) mL/min/100g and 5.9 (0.5) mL/min/100g for the HS/CR and HS/CR+MC-2 groups, respectively (P <.05). Effective hepatic blood flow remained constant in the sham groups throughout the experimental protocol. Organ edema was increased in the ileum and liver in the HS/CR vs sham group, and MC-2 decreased edema in the ileum vs the HS/CR group. MC-2 in HS also decreased levels of alanine aminotransferase, zonula occludens-1, and interleukin-1β compared with HS/CR alone.

CONCLUSIONS AND RELEVANCE

MC-2 was associated with decreased liver injury, enhanced effective hepatic blood flow, decreased cytokines, and prevention of edema formation in the ileum when administered with CR following HS. These data suggest that the MC-2 peptide could be a potential therapeutic approach to target cytokine and chemokine interactions, which might limit multiple organ failure and decrease mortality in hemorrhagic shock.

Intravitreal triamcinolone acetonide, retinal microglia and retinal ganglion cell apoptosis in the optic nerve crush model

PURPOSE

To evaluate the effect of intravitreal triamcinolone acetonide (TA) on the activation of retinal microglia cells (RMGCs) and survival of retinal ganglion cells (RGCs) in an optic nerve crush (ONC) model.

METHODS

Adult female Sprague-Dawley rats underwent a standardized ONC and either received an intravitreal injection of TA (TA group) or of phosphate-buffered saline (PBS, PBS group) in the right eyes. At 1, 3, 7, 14 and 28 days after the ONC, the animals were killed. The retinas were examined by immunohistochemistry, light microscopy, Western blot or retrograde labelling of RGCs by fluorogold injected into the superior colliculi.

RESULTS

The TA group as compared to the PBS control group showed a significantly (p < 0.0001) lower density of activated RMGCs, at 14 days [4.2 ± 1.6 versus 9.3 ± 2.2 cells/high-power microscopic field (HPF)] and at 28 days (2.3 ± 1.1 versus 4.4 ± 1.5 cells/HPF), and with a significantly lower expression of inflammatory factors. Central density of RGCs as stained by haematoxylin-eosin or by fluorogold was significantly (all p < 0.05) more reduced in the PBS group than in the TA group at days 14 and 28 after baseline. The survival rate (cell density in the study eye as compared to cell density in the contralateral unaffected eye) was significantly higher in the TA group than in the PBS group on days 14 (58% versus 45%; p = 0.003) and 28 (52% versus 41%; p = 0.022).

CONCLUSIONS

Intravitreal TA as compared to intravitreal PBS was associated with a lower density of activated RMGCs and a higher density of surviving RGCs in an ONC model.

Impact of Injury Severity on Dynamic Inflammation Networks Following Blunt Trauma

INTRODUCTION

Clinical outcomes following trauma depend on the extent of injury and the host's response to injury, along with medical care. We hypothesized that dynamic networks of systemic inflammation manifest differently as a function of injury severity in human blunt trauma.

STUDY DESIGN

From a cohort of 472 blunt trauma survivors studied following institutional review board approval, three Injury Severity Score (ISS) subcohorts were derived after matching for age and sex: mild ISS (49 patients [33 males and 16 females, aged 42 ± 1.9 years; ISS 9.5 ± 0.4]); moderate ISS (49 patients [33 males and 16 females, aged 42 ± 1.9; ISS 19.9 ± 0.4]), and severe ISS (49 patients [33 males and 16 females, aged 42 ± 2.5 years; ISS 33 ± 1.1]). Multiple inflammatory mediators were assessed in serial blood samples. Dynamic Bayesian Network inference was utilized to infer causal relationships based on probabilistic measures.

RESULTS

Intensive care unit length of stay, total length of stay, days on mechanical ventilation, Marshall Multiple Organ Dysfunction score, prevalence of prehospital hypotension and nosocomial infection, and admission lactate and base deficit were elevated as a function of ISS. Multiple circulating inflammatory mediators were significantly elevated in severe ISS versus moderate or mild ISS over both the first 24 h and out to 7 days after injury. Dynamic Bayesian Network suggested that interleukin 6 production in severe ISS was affected by monocyte chemotactic protein 1/CCL2, monokine inducible by interferon γ (MIG)/CXCL9, and IP-10/CXCL10; by monocyte chemotactic protein 1/CCL2 and MIG/CXCL9 in moderate ISS; and by MIG/CXCL9 alone in mild ISS over 7 days after injury.

CONCLUSIONS

Injury Severity Score correlates linearly with morbidity, prevalence of infection, and early systemic inflammatory connectivity of chemokines to interleukin 6.

Temporal Patterns of Circulating Inflammation Biomarker Networks Differentiate Susceptibility to Nosocomial Infection Following Blunt Trauma in Humans

BACKGROUND

Severe traumatic injury can lead to immune dysfunction that renders trauma patients susceptible to nosocomial infections (NI) and prolonged intensive care unit (ICU) stays. We hypothesized that early circulating biomarker patterns following trauma would correlate with sustained immune dysregulation associated with NI and remote organ failure.

METHODS

In a cohort of 472 blunt trauma survivors studied over an 8-year period, 127 patients (27%) were diagnosed with NI versus 345 trauma patients without NI. To perform a pairwise, case-control study with 1:1 matching, 44 of the NI patients were compared with 44 no-NI trauma patients selected by matching patient demographics and injury characteristics. Plasma obtained upon admission and over time were assayed for 26 inflammatory mediators and analyzed for the presence of dynamic networks.

RESULTS

Significant differences in ICU length of stay (LOS), hospital LOS, and days on mechanical ventilation were observed in the NI patients versus no-NI patients. Although NI was not detected until day 7, multiple mediators were significantly elevated within the first 24 hours in patients who developed NI. Circulating inflammation biomarkers exhibited 4 distinct dynamic patterns, of which 2 clearly distinguish patients destined to develop NI from those who did not. Mediator network connectivity analysis revealed a higher, coordinated degree of activation of both innate and lymphoid pathways in the NI patients over the initial 24 hours.

CONCLUSIONS

These studies implicate unique dynamic immune responses, reflected in circulating biomarkers that differentiate patients prone to persistent critical illness and infections following injury, independent of mechanism of injury, injury severity, age, or sex.

Modeling acute traumatic injury

Acute traumatic injury is a complex disease that has remained a leading cause of death, which affects all ages in our society. Direct mechanical insult to tissues may result in physiological and immunologic disturbances brought about by blood loss, coagulopathy, as well as ischemia and reperfusion insults. This inappropriate response leads to an abnormal release of endogenous mediators of inflammation that synergistically contribute to the incidence of morbidity and mortality. This aberrant activation and suppression of the immune system follows a bimodal pattern, wherein activation of the innate immune responses is followed by an anti-inflammatory response with suppression of the adaptive immunity, which can subsequently lead secondary insults and multiple organ dysfunction. Traumatic injury rodent and swine models have been used to describe many of the underlying pathologic mechanisms, which have led to an improved understanding of the morbidity and mortality associated with critically ill trauma patients. The enigmatic immunopathology of the human immunologic response after severe trauma, however, has never more been apparent and there grows a need for a clinically relevant animal model, which mimics this immune physiology to enhance the care of the most severely injured. This has necessitated preclinical studies in a more closely related model system, the nonhuman primate. In this review article, we summarize animal models of trauma that have provided insight into the clinical response and understanding of cellular mechanisms involved in the onset and progression of ischemia-reperfusion injury as well as describe future treatment options using immunomodulation-based strategies.

Expression levels of tumor necrosis factor-α and the corresponding receptors are correlated with trauma severity

This study investigated the plasma levels of tumor necrosis factor α (TNF-α) and the expression levels of TNF receptors (TNFRs) in patients with multiple trauma, together with the association between the levels of this cytokine and these cytokine receptors with the severity of traumatic injury. Blood samples were obtained from 60 multiple trauma patients at hospital admission (within 2 h of injury), and 6–8 h and 1–5 days after admission. The plasma levels of TNF-α and TNFR1/TNFR2 were detected using enzyme immunoassay. TNFR1 and TNFR2 expression levels on leukocytes, including neutrophils, lymphocytes and monocytes, were determined by flow cytometry. Clinical parameters were determined by injury severity score (ISS). At hospital admission, the plasma TNF-α and soluble TNFR levels in the trauma patients were elevated compared with those of healthy controls. Increased expression levels of TNFR1 and TNFR2 were also detected on leukocytes, particularly on lymphocytes and monocytes. The expression levels of the cytokine and the corresponding receptors were correlated with the ISS. TNF-α and TNFR expression levels remained significantly elevated for up to the third to fifth day following the traumatic injury. In the trauma patients, increased levels of TNF-α and TNFRs were correlated with the severity of traumatic injury in the early post-injury period, supporting the hypothesis that trauma-provoked organ dysfunction may be caused by an overwhelming auto-destructive inflammatory response.

The impact of two different transfusion strategies on patient immune response during major abdominal surgery: a preliminary report

Blood transfusion is associated with well-known risks. We investigated the difference between a restrictive versus a liberal transfusion strategy on the immune response, as expressed by the production of inflammatory mediators, in patients subjected to major abdominal surgery procedures. Fifty-eight patients undergoing major abdominal surgery were randomized preoperatively to either a restrictive transfusion protocol or a liberal transfusion protocol (with transfusion if hemoglobin dropped below 7.7 g dL(-1) or 9.9 g dL(-1), respectively). In a subgroup of 20 patients randomly selected from the original allocation groups, blood was sampled for measurement of IL-6, IL-10, and TNFα. Postoperative levels of IL-10 were higher in the liberal transfusion group on the first postoperative day (49.82 ± 29.07 vs. 15.83 ± 13.22 pg mL(-1), P < 0.05). Peak postoperative IL-10 levels correlated with the units of blood transfused as well as the mean duration of storage and the storage time of the oldest unit transfused (r(2) = 0.38, P = 0.032, r(2) = 0.52, P = 0.007, and r(2) = 0.68, P<0.001, respectively). IL-10 levels were elevated in patients with a more liberal red blood cell transfusion strategy. The strength of the association between anti-inflammatory IL-10 and transfusion variables indicates that IL-10 may be an important factor in transfusion-associated immunomodulation. This trial is registered under ClinicalTrials.gov Identifier: NCT02020525.

Increased circulating advanced glycation endproducts (AGEs) in acute trauma patients

BACKGROUND

Circulating levels of pro-inflammatory advanced glycation end products (AGEs) are increased in diabetes and other conditions characterized by chronically elevated oxidant stress (OS). OS also increases after acute trauma and is implicated in the development of complications such as multiple organ failure. Herein, we assess the effect of acute OS on circulating levels of AGEs in a cohort of acute trauma victims.

METHODS

An observational study was performed at a large Level 1 Trauma Center. Blood samples for measurement of two AGEs, carboxymethyllysine (CML) and methylglyoxal (MG), were obtained at admission, and serially afterwards in patients admitted to the ICU. Demographics, dietary history, markers of injury severity and ICU morbidity and mortality data were collected.

RESULTS

One hundred and fifty-six trauma patients (TP) (age: 39±17 years, 83% males, injury severity score: 18±14) were included in the study. TP had significantly higher serum AGE levels than normal healthy controls (CML, TP 12.4±8.2 U/mL vs. controls 8.9±5.3 U/mL, p<0.001; MG, TP 2.1±1.4 nmol/mL vs. controls 0.79±0.3 nmol/mL, p<0.001). Admission serum AGE levels in 49 severe TP admitted to the ICU were lower than those who were not. However, among the ICU patients, serum AGEs increased further for about 7 days in patients with an uncomplicated course, and remained markedly elevated in those with a complicated course.

CONCLUSIONS

Circulating AGEs are transiently increased after acute trauma and persistently elevated AGE levels are associated with greater severity of injury.

Bedside ultrasound in resuscitation and the rapid ultrasound in shock protocol

Assessment of hemodynamic status in a shock state remains a challenging issue in Emergency Medicine and Critical Care. As the use of invasive hemodynamic monitoring declines, bedside-focused ultrasound has become a valuable tool in the evaluation and management of patients in shock. No longer a means to simply evaluate organ anatomy, ultrasound has expanded to become a rapid and noninvasive method for the assessment of patient physiology. Clinicians caring for critical patients should strongly consider integrating ultrasound into their resuscitation pathways.

Impact of shed blood products on stimulated cytokine release in an in vitro model of transfusion

BACKGROUND

Blood transfusion is reported to suppress the recipient's immune system. To avoid allogenic transfusion, post-operative shed blood retransfusion is a commonly used method. The aim of this study was to investigate the dose-related impact of post-operatively collected shed blood products on the stimulated cytokine release in an in vitro model of transfusion.

METHODS

Venous blood samples obtained from 20 patients undergoing hip arthroplasty were mixed with post-operatively collected unprocessed, processed, and irradiated shed blood as well as normal saline as a control. Shed blood was processed by centrifugation and separating the cellular fraction from the soluble fraction and washing the cellular fraction with phosphate buffered saline to eliminate any cell fragments and other substances. Mixing ratios were 1:3, 1:1, and 3:1. Endotoxin-stimulated release of Tumor Necrosis Factor-alpha (TNF-α) was measured after 24 h of culture by enzyme-linked immunosorbent assay.

RESULTS

Unprocessed, irradiated shed blood and the soluble fraction caused a significant suppression of stimulated TNF-α release compared to control. The addition of the cellular shed blood fraction had no significant influence on the TNF-α release compared to control.

CONCLUSION

Shed blood and its components caused a dose-independent immunomodulation as indicated by a suppressed stimulated TNF-α release. Leukocytes seem to play a minor role, as we observed a sustained suppression after transfusion of γ-irradiated shed blood. Only the elimination of soluble factors by centrifugation and followed by an additional washing step prevented the observed suppression of TNF-α. Thus, we assume that washing of shed blood can prevent potential detrimental effects.

Tumor necrosis factor-alpha (TNF-α) levels in aqueous humor of primary open angle glaucoma

Purpose:

Tumor necrosis factor alpha (TNF-α), a macrophage/monocyte derived pluripotent cytokine is associated with tissue ischemia, neuronal damage and remodeling. The physiological level of TNF-α in aqueous humor of normal and glaucomatous eyes is unknown. In this study, we evaluated the TNF-α levels in aqueous in patients with primary open angle glaucoma (POAG) and compared them to controls.

Methods:

50–100 μL of undiluted aqueous humor samples were obtained from eyes of 32 POAG patients who underwent cataract extraction, trabeculectomy or aqueous shunt implantation. Controls were obtained from 32 normal subjects who underwent routine cataract surgery. TNF-α levels were quantified using singleplex bead immunoassay analysis.

Results:

The average TNF-α level in POAG samples was 2.72 ± 1.5 pg/mL (mean ± SD). The average TNF-α level in normal samples was 1.59 ± 0.46 pg/mL (mean ± SD). Significant increase of TNF-α levels in POAG samples was noted in comparison to normal samples (P < 0.001).

Conclusion:

TNF-α levels are elevated in aqueous in patients with POAG compared to normal subjects based on highly sensitive Luminex^® bead immunoassay and may be a reliable biomarker in the progression of glaucoma.

Attenuated hypocholesterolemia following severe trauma signals risk for late ventilator-associated pneumonia, ventilator dependency, and death: a retrospective study of consecutive patients

BACKGROUND

Post-traumatic ventilator-associated pneumonia (VAP) is a substantial clinical problem that increases hospital costs and typically adds to the duration of mechanical ventilation. We evaluated the impact of VAP on ventilator days. We also assessed 48-hour total blood cholesterol (TC) and other potential risk factors for the development of VAP.

METHODS

We performed a retrospective study of consecutive trauma patients requiring emergency tracheal intubation and evaluated TC, age, gender, ethanol status, smoker status, injury mechanism, chest injury, brain injury, Injury Severity Score (ISS), shock, day-one hypoxemia, and RBC transfusion as potential risks for VAP.

RESULTS

The 152 patients had ISS 28.1, brain injury 68.4%, VAP 50.0%, ventilator days 14.3, and death 9.9%. Ventilator days were increased with late VAP (p < 0.0001). TC was 110.7 mg/dL with expected TC 197.5 mg/dL. TC was lower with chest injury, shock, and RBC transfusion but, higher with brain injury (p ≤ 0.01). TC decreased as ISS increased (p = 0.01). However, one patient subset (ISS ≥ 20-&-TC ≥ 90 mg/dL) had a relative increase in TC despite an increase in ISS. ISS ≥ 20-&-TC ≥ 90 mg/dL, but not ISS alone, was the only independent predictor of late VAP (OR 3.0; p = 0.002). ISS ≥ 20-&-TC ≥ 90 mg/dL and day-one hypoxemia were the only independent predictors for increased ventilator days (p = 0.01). ISS ≥ 20-&-TC ≥ 90 mg/dL, but not ISS alone, was the only predictor of death (OR 3.8; p = 0.03).

CONCLUSIONS

Severe traumatic injury produced substantial hypocholesterolemia that is greater with chest injury, shock, and RBC transfusion, but less with brain injury. Total blood cholesterol tended to decrease with increasing injury severity. However, attenuated hypocholesterolemia (ISS ≥ 20-&-TC ≥ 90 mg/dL) represents a unique response that can occur with critical injury. Attenuated hypocholesterolemia signals early risk for late VAP, ventilator dependency, and death.

Relationships between markers of inflammation, severity of injury, and clinical outcomes in hemorrhagic shock

This study was performed to investigate the relationships between markers of inflammation in serum (interleukin-6 [IL-6], interleukin-10 [IL-10], and granulocyte elastase [GE]), severity of injury, and clinical outcomes, and to evaluate the predictive value of these markers for major complications and mortality. This study, which was conducted between August 2003 and May 2005, examined patients older than 16 y who were admitted to the Emergency Unit of the Uludag University Medical School within 12 h after trauma, and who had traumatic hemorrhagic shock (THS) at admission. Three groups were established: the THS group (n=20), the pure hemorrhagic shock (PHS) group (n=20), and the healthy control group (n=20). Demographic data were recorded for all subjects, and blood samples were taken for lactate, base excess, GE, IL-6, and IL-10 measurements. The Glasgow Coma Score, the Revised Trauma Score, the Injury Severity Score, the New Injury Severity Score, and the Trauma Score-Injury Severity Score were calculated; complications and final clinical outcomes were monitored. A total of 35 men and 25 women were included in the study; mean patient age was 41+/-17 y. In the THS group, scores were as follows: Revised Trauma Score, 10.2+/-2.2; Trauma Score-Injury Severity Score, 0.86+/-0.2; Injury Severity Score, 24.8+/-9.0; and New Injury Severity Score, 32.7+/-9.0. IL-6, IL-10, lactate, and base excess levels in the THS group were significantly higher than those in the PHS and healthy control groups. The serum GE level of the THS group was significantly higher than that of the healthy control group, but it did not differ significantly from that of the PHS group. Complications such as sepsis, acute respiratory distress syndrome, and multiple organ failure occurred in 50% of the THS group and in 20% of the PHS group. Mortality was 30% in the THS group and 10% in the PHS group. In the THS group, no significant differences were noted between markers of inflammation and trauma scores of patients who died and those who survived. The investigators concluded that although the levels of markers of inflammation increased in THS patients, they were inadequate for predicting mortality and the development of complications such as acute respiratory distress syndrome, multiple organ failure, and sepsis. A larger study based on the use of serial marker measurements is warranted.

Surgical stress response

Recent advances in molecular medicine have allowed the characterization and quantification of inflammatory cascades following surgery and trauma. Activation of immune cells is followed by the release of various cytokines as well as by migration of leukocytes into inflamed tissues. Various methods have been developed in order to modulate the immune-inflammatory system and at the same time to prevent overreaction and unexpected complications. In this context, the magnitude of surgical stress exerted on the patient is of paramount importance. Several factors, either controllable or not, are known to contribute to the development and amplification of the 'surgical stress response'. Therefore, they should be taken into consideration by both surgical practitioners and other medical specialties involved in the management of the traumatised patient.

In Vitro Restoration of Post-Operatively Decreased IFN-Gamma Levels After Cardiac Surgery and Its Effect on Pro- and Anti-Inflammatory Mediators

BACKGROUND

A decreased synthesis of interferon gamma (IFN-gamma) by TH 1 lymphocytes after cardiac operations with cardiopulmonary bypass (CPB) is part of the inflammatory response to local operative and systemic traumas. The consequences of this mechanism on the release of pro- and anti-inflammatory cytokines remain unclear. To evaluate the role of IFN-gamma, we added recombinant IFN-gamma to peripheral blood mononuclear cells (PBMCs) on the first post-operative day in an attempt to restore pre-operative values and then measured the release of pro- and anti-inflammatory cytokines in vitro.

METHODS

PBMCs of 10 patients scheduled for elective coronary artery bypass grafting (CABG) were obtained pre-operatively (d0) and on the first (d1) and third (d3) post-operative days. The release of IL-6, IL-8, TNF-alpha, IFN-gamma, IL-10, IL-2, and IL-4 was studied after stimulation (48 h) with PHA (phytohemagglutinin) and LPS (lipopolysaccharide) in the absence or presence of recombinant human IFN-gamma.

RESULTS

Endogenous IFN-gamma synthesis was suppressed on d1. Adding exogenous IFN-gamma restored IFN-gamma levels to normal on d1 and doubled IFN-gamma levels on d0 and d3. The addition of IFN-gamma increased TNF-alpha levels up to 250% on d1 and IL-2 synthesis by 75% on d1 and d3; the IL-2 levels, however, were still significantly depressed. The addition of recombinant IFN-gamma did not affect the synthesis of IL-6, IL-8, IL-10, and IL-4.

CONCLUSIONS

Contrary to our expectations, the in vitro release of IL-6 and IL-8 as well as IL-10 and IL-4 was not influenced by the addition of IFN-gamma. However, TNF-alpha production in isolated PBMC cultures increased significantly on the first post-operative day. This may indicate a hyper-reactivity of PBMCs to IFN-gamma and suggests that the decrease in IFN-gamma synthesis might prevent an excessive stimulation of the non-specific immune system by high TNF-alpha levels after cardiac surgery.

DELAYED ELEVATION OF SOLUBLE TUMOR NECROSIS FACTOR RECEPTORS P75 AND P55 IN CEREBROSPINAL FLUID AND PLASMA AFTER TRAUMATIC BRAIN INJURY

Recent studies have reported a significant inflammatory reaction in the brain and the systemic circulation after traumatic brain injury (TBI). Although there is growing knowledge and understanding of the mechanisms and mediators involved in the proinflammatory reaction, little is known about the anti-inflammatory mediators in the brain. As tumor necrosis factor alpha (TNF-alpha) plays a detrimental role in the initiation and promotion of the proinflammatory reactions after TBI, the endogenous scavenger system, represented by the soluble TNF receptors (sTNFRs) p55 and p75, seems to have an important anti-inflammatory capacity by binding to circulating TNF-alpha. To evaluate this potentially anti-inflammatory response to trauma, we analyzed sTNFR p55 and p75 in paired plasma/cerebrospinal fluid (CSF) samples of 29 patients who encountered TBI. Values were compared with reference values obtained from healthy volunteers (n = 91). Patients with TBI showed significantly (P < 0.001) elevated sTNFR p55 and p75 values starting from day 2 and lasting until day 10 if compared with reference values. In contrast to the early increased plasma values p55 and p75 showed slowly increasing CSF values starting on day 4 and 3, respectively. Significantly (P < 0.001) increased CSF values of p 55 were determined on days 4 to 6 and day 9. p75 showed significantly (P < 0.001) elevated values if compared with control values on days 7 and 9. The sTNFR p55 and p75 show a distinct and long-lasting elevation in plasma of patients after TBI. In contrast, CSF values display a delayed and less intense elevation of both receptors in patients with TBI. These findings are suggestive of an imbalance of the proinflammatory and anti-inflammatory reactions of the central nervous system after trauma, with an emphasis on the proinflammatory mechanisms and a slow increase of potentially anti-inflammatory mediators such as the soluble TNFRs after TBI.

Dose-dependent improvements in outcome with adenoviral expression of interleukin-10 in a murine model of multisystem organ failure

Targeted expression of interleukin-10 (IL-10) has been proposed as a means to suppress acute and chronic inflammation. We explored the capacity of targeted adenoviral expression of human or viral IL-10 to improve outcome in a zymosan-induced model of acute lung injury and multisystem organ failure. Intratracheal administration of adenovirus expressing either human or viral IL-10 prior to zymosan administration significantly improved survival at a dose of 10(7) particles (P<0.01), whereas the same recombinant vectors were ineffective at 10(8) particles and increased mortality at 10(9) particles. Improved survival after administration of 10(7) particles of adenovirus expressing viral or human IL-10 was associated with local tissue expression of IL-10 (100-300 pg/g wet wt). In contrast, mortality after administration of 10(9) particles was associated with markedly elevated IL-10 expression, both in the lung (10000-70000 pg/g wet wt) and systemically (1000-3000 pg/ml plasma), with evidence of an exaggerated systemic inflammatory response (plasma IL-6 and TNFalpha). Targeted gene expression of IL-10 can be used to treat acute inflammatory processes, but increased doses resulting in its systemic release are not associated with improvements in outcome, and may actually exacerbate acute inflammatory processes.

Relation between severity of injury and the early activation of interleukins in multiple-injured patients

The aim of this study was to evaluate the relation between severity of injury and the early activation of interleukins in multiple-injured patients. Ninety-nine patients with multiple injuries were included in this prospective study. Plasma levels of interleukin (IL)-1, IL-2, IL-6, IL-8 and TNF-alpha were measured. Injury Severity Score (ISS), Revised Trauma Score (RTS), Glasgow Coma Score (GCS) and the Acute Physiology and Chronic Health Evaluation II (APACHE-II) were all recorded. Of the 99 patients, 82 were male and 17 were female. The mean age was 26.6+/-20.7 years. The mortality rate for this series was 17%. Patients who died from trauma exhibited a significant increase for IL-2, IL-6 and IL-8 in comparison with patients who survived. Significant differences for ISS, RTS and GCS were found between survivors and non-survivors. Values in all patients with ISS>16 were increased and these increases were significant for IL-6 and IL-2. These data show that the initial increase of IL-2, IL-6 and IL-8 might predict the patients with a high possibility of mortality and a significant increase of IL-2 and IL-6 in patients with ISS>16 might be used in a new developed trauma score combined with ISS as an indicator for the injury severity.

[The importance of cytokines in the posttraumatic inflammatory reaction]

Alterations in the immune response after multiple trauma, posttraumatic sepsis and surgery are recognized as physiological reactions of the organism to restore homeostasis. The level of these immunological changes correlates with the degree of tissue damage as well as with the severity of haemorrhage and ischaemia. Cytokines are known to be integral components of this immune response. The local release of pro- and antiinflammatory cytokines after severe trauma indicates their potential to induce systemic immunological alterations. It appears that the balance or imbalance of these different cytokines partly controls the clinical course in these patients. Overproduction of either proinflammatory cytokines or antiinflammatory mediators may result in organ dysfunction. Whereas predominance of the proinflammatory response leads to the systemic inflammatory response syndrome (SIRS), the antiinflammatory reaction may result in immune suppression with an enhanced risk of infectious complications. Systemic inflammation, as well as immune suppression, are thought to play a decisive role in the development of multiple organ dysfunction syndrome (MODS). The major proinflammatory cytokines involved in the response to trauma and surgery include tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-6 and IL-8. These cytokines, which are predominantly produced by monocytes and macrophages, mediate a variety of frequently overlapping effects, and their actions can be additive. TNF-alpha and IL-1beta are early regulators of the immune response and both induce the release of secondary cytokines, such as IL-6 and IL-8. IL-10 is an antiinflammatory cytokine which reduces the synthesis of proinflammatory mediators. Other important antiinflammatory mediators are soluble TNF receptors and the IL-1 receptor antagonist, which interfere with the effects of TNF-alpha and IL-1beta.Early evaluation of the prognosis of polytraumatized patients and assessment of their clinical status is known to be difficult. Therefore, in several clinical studies, cytokine levels during the posttraumatic course have been determined with the aim of finding predictive markers of patient outcome. The purpose of this review was to highlight our current knowledge on the interaction of posttraumatic immune reactivity and the development of complications. A better understanding of these mechanisms might lead to the introduction of preventive and therapeutic strategies into clinical practice.

[Damage control orthopedics]

BACKGROUND

In the management of patients with multiple injuries, the concept of damage control orthopedics (DCO) is still a matter of controversy. Thus, the clinical value of DCO remains unclear and should be evaluated on an evidence-based level by a review of the current literature.

RESULTS

The work of various authors has demonstrated an association between injury severity and the clinical immuno-inflammatory response and its prognostic relevance regarding organ dysfunction or organ failure and clinical outcome. Research data published by the authors and other investigators have clearly demonstrated an additional inflammatory response caused by surgical trauma which is significantly higher after primary intramedullary fracture treatment than after external fracture stabilization. In contrast, a generally minor inflammatory response seems to be associated with intramedullary nailing for secondary conversion osteosynthesis. Three retrospective cohort studies have shown a reduction of organ dysfunction and an improvement of survival with the DCO approach. Simultaneously, it was demonstrated that primary external fracture fixation and secondary conversion to definite osteosynthesis is not associated with an increased rate of local or systemic complications.

CONCLUSIONS

The advocates of DCO claim that patients with multiple injuries including severe brain and chest injuries as well as those with an unstable cardiopulmonary or circulatory condition are at high risk of developing a severe systemic immuno-inflammatory reaction during early total fracture care. Therefore, they recommend primary minimally invasive external fracture stabilization in these patients to avoid additional surgical trauma and that definitive secondary fracture care should be performed after medical stabilization of the patient in intensive care.

[Intensive medicine criteria for operability]

BACKGROUND

Operability is mainly determined by the interaction between the magnitude of an operation and the patient's tolerance for the procedure. A further factor is the benefit gained by performing the procedure versus the sequelae caused by its omission.

RESULTS

Major operations within the first 3 days after trauma appear to have an increased risk, particularly if they are performed during impaired respiratory function (pO(2)/F(i)O(2) ratio <280 mmHg) or increased inflammatory status. Such interventions are recommended to be postponed until a later time. Surgical interventions after day 3 require an individual decision with respect to the timing of the operation. Criteria that are of value in this decision comprise a pO(2)/F(i)O(2) ratio above 280 mmHg, a stable circulation, a platelet count above 100.000 to 150.000/microl, normal global coagulation tests, only moderate systemic inflammation as indicated by C-reactive protein or interleukin-6 levels, a normal fluid balance and in case of traumatic brain injury there should be no signs of increased intracranial pressure. Whether liver function, level of PEEP, catecholamine therapy and other factors will influence operability remains to be elucidated.

CONCLUSION

The pathophysiological consequences of accidental trauma show a phasic course with respect to the immunomodulatory response. An operative trauma inflicted by a secondary surgical intervention contributes an additional burden. Depending on the inflammatory phase during which this secondary hit is inflicted there may be a disturbance of homoeostasis that may even lead to multiple organ failure. Whether this happens can depend on type and magnitude of the surgical intervention. Minor operations result in smaller systemic effects and will be less critical with respect to operability.

The immuno-inflammatory response to trauma

The systemic inflammatory response syndrome is a well recognized physiological entity being part of our homeostatic mechanisms. It represents the cascade of inflammatory reactions initiated in the immediate aftermath following trauma reflecting the state of alertness that our body undergoes in order to fight for survival. A variety of inflammatory mediators and cellular elements are involved during this process interacting amongst each other. This allows communication between the different organ systems and thus regulating local and systemic responses. We have just begun to characterize and quantify the immuno-inflammatory response to trauma and this has opened new horizons in the way we understand the pathophysiological response to injury. As our knowledge evolves new therapeutic agents and innovative treatment plans will be developed contributing to increased survival rates in patients with multiple injuries.

Serum acute phase protein concentrations after hysterectomy with and without low-molecular-weight heparin thrombosis prophylaxis

Background. Low-molecular-weight heparin (LMWH) is recommended for venous thrombosis prophylaxis. There are several lines of evidence that heparins exhibit anti-inflammatory properties in addition to their anticoagulant activity. Therefore, we decided to estimate the concentrations of C-reactive protein (CRP) and haptoglobin, as acute-phase proteins, in the blood serum of patients who underwent total abdominal hysterectomy with and without the LMWH administration. Method. Forty-two women were studied, including 26 patients treated with enoxaparin and a group of 16 women without thrombosis prophylaxis. Haptoglobin and CRP concentrations were measured in serum samples obtained before the operation and also 8, 24, 48, 72, 96, and 192 hr after surgery. Results. Serum CRP level measured 8 hr after the operation was significantly higher in the group without thrombosis prophylaxis, however, no statistically significant differences in the concentration of CRP between studied groups in the other time periods were found. There were no statistically significant differences in serum haptoglobin levels between the groups of patients in all time periods. Conclusion. Administration of low-molecular-weight heparin may affect CRP production, however, further studies are still needed in order to clarify the exact immunosuppressive action of heparins.

Pathophysiology of polytrauma

Immediate and early trauma deaths are determined by primary brain injuries, or significant blood loss (haemorrhagic shock), while late mortality is caused by secondary brain injuries and host defence failure. First hits (hypoxia, hypotension, organ and soft tissue injuries, fractures), as well as second hits (e.g. ischaemia/reperfusion injuries, compartment syndromes, operative interventions, infections), induce a host defence response. This is characterized by local and systemic release of pro-inflammatory cytokines, arachidonic acid metabolites, proteins of the contact phase and coagulation systems, complement factors and acute phase proteins, as well as hormonal mediators: it is defined as systemic inflammatory response syndrome (SIRS), according to clinical parameters. However, in parallel, anti-inflammatory mediators are produced (compensatory anti-inflammatory response syndrome (CARS). An imbalance of these dual immune responses seems to be responsible for organ dysfunction and increased susceptibility to infections. Endothelial cell damage, accumulation of leukocytes, disseminated intravascular coagulation (DIC) and microcirculatory disturbances lead finally to apoptosis and necrosis of parenchymal cells, with the development of multiple organ dysfunction syndrome (MODS), or multiple organ failure (MOF). Whereas most clinical trials with anti-inflammatory, anti-coagulant, or antioxidant strategies failed, the implementation of pre- and in-hospital trauma protocols and the principle of damage control procedures have reduced post-traumatic complications. However, the development of immunomonitoring will help in the selection of patients at risk of post-traumatic complications and, thereby, the choice of the most appropriate treatment protocols for severely injured patients.

CEREBROSPINAL FLUID CONCENTRATIONS OF ANTI-INFLAMMATORY MEDIATORS IN EARLY-PHASE SEVERE TRAUMATIC BRAIN INJURY

In our previous study of patients with early-phase severe traumatic brain injury (TBI), the anti-inflammatory interleukin (IL)-10 concentration was lower in cerebrospinal fluid (CSF) than in serum, whereas proinflammatory IL-1beta and tumor necrosis factor (TNF)-alpha concentrations were higher in CSF than in serum. To clarify the influence of additional injury on this disproportion between proinflammatory and anti-inflammatory mediators, we compared their CSF and serum concentrations in patients with severe TBI with and without additional injury. All 35 study patients (18 with and 17 without additional injury) had a Glasgow Coma Scale score of 8 or less upon admission. With the exception of additional injury, clinical characteristics did not differ significantly between groups. CSF and serum concentrations of two proinflammatory mediators (IL-1beta and TNF-alpha,) and three anti-inflammatory mediators (IL-1 receptor antagonist [IL-1ra], soluble TNF receptor-I [sTNFr-I], and IL-10) were measured and compared at 6 h after injury. CSF concentrations of proinflammatory mediators were much higher than the corresponding serum concentrations in both patient groups (P < 0.001). In contrast, serum concentrations of anti-inflammatory mediators were much higher than the paired CSF concentrations in patients with additional injury (P < 0.001), but serum concentrations were lower than or equal to the corresponding CSF concentrations in patients without additional injury. CSF concentrations of IL-1beta, IL-1ra, sTNFr-I, and IL-10 were significantly higher (P < 0.01 for all) in patients with high intracranial pressure (ICP; n = 11) than in patients with low ICP (n = 24), and were also significantly higher (P < 0.05 for all) in patients with an unfavorable outcome (n = 14) than in patients with a favorable outcome (n = 21). These findings indicate that increased serum concentrations of anti-inflammatory mediators after severe TBI are mainly due to additional extracranial injury. We conclude that anti-inflammatory mediators in CSF may be useful indicators of the severity of brain damage in terms of ICP as well as overall prognosis of patients with severe TBI.

Endotoxin reduces CD95-induced neutrophil apoptosis by cIAP-2-mediated caspase-3 degradation

BACKGROUND

Reduced apoptosis of neutrophil granulocytes (PMN) contributes to pathogenesis of systemic inflammatory response syndrome, sepsis, and multiple organ dysfunction syndrome. The intracellular inhibitor of apoptosis proteins has been shown to inhibit activated caspase-3. We investigated the turnover dynamics of cIAP-2 mRNA and caspase-3 protein in a neutrophil ex vivo model of sepsis.

STUDY DESIGN

PMN (1 x 10(6)/mL) from 7 healthy volunteers were preincubated with endotoxin (lipopolysaccharide [LPS], 1 microg/mL) for 5 hours, followed by an additional hour with or without the proteasome inhibitor (30 microM), before incubation with or without agonistic CD95 antibody (100 ng/mL) for another 16 hours. Apoptosis was quantified by Annexin-V and propidium iodide staining by flow cytometry (using a fluorescence-activated cell sorter). Caspase-3 activity was determined by DEVD-afc-cleavage assay. Expression of ubiquitinated caspase-3 and cIAP-2 protein was detected by Western blot analysis and cIAP-2 mRNA by reverse transcriptase-polymerase chain reaction.

RESULTS

Within 2 hours LPS induced cIAP-2 mRNA and protein. In addition, LPS increased ubiquitination of activated caspase-3. LPS significantly (p < 0.05) reduced spontaneous (66.1 +/- 2.3% to 24.8 +/- 4.8%) and CD95-induced (90.8 +/- 0.9% to 64.3 +/- 4.2%) apoptosis and caspase-3 activation. Inhibition of the proteasome completely abolished the antiapoptotic effect of LPS on spontaneous (52.6 +/- 2.4%) and CD95-induced (88.7 +/- 2.6%) apoptosis and degradation of caspase-3.

CONCLUSIONS

Induction of cIAP-2 by endotoxins and accelerated degradation of activated caspase-3 by the proteasome might be responsible for reduced apoptosis in PMN during sepsis.

Effect of the LT-alpha (+250 G/A) polymorphism on markers of inflammation and clinical outcome in critically ill patients

BACKGROUND

Tumor necrosis factor alpha as a central mediator of the inflammation cascade is correlated to sepsis outcome. Tumor necrosis factor beta (LT-alpha) binds the same cell receptor and polymorphisms in both genes have been described. To evaluate the importance of the LT-alpha (+250 G/A) polymorphism for the clinical outcome of patients developing postsurgical sepsis, 85 patients were consecutively included into this study.

METHODS

Blood samples were obtained for analysis of the biallelic LT-alpha (+250 G/A) polymorphism and for determination of serum levels of sTNF-R1, TNF-alpha, IL-6, IL-8, IL-10, procalcitonin, and neopterin. Cytokine levels were measured repeatedly until the patients' discharge from the ICU.

RESULTS

The allele frequency was 0.28 for TNFB1 and 0.72 for TNFB2. The genotype distribution was TNFB1 homozygotes 4/79 (5.1%), TNFB1/TNFB2 heterozygotes 37/79 (46.8%), and TNFB2 homozygotes 38/79 (48.1%). Fifty-four out of 80 (67.5%) fulfilled the criteria for severe sepsis; 36/80 (45.0%) developed septic shock. Multiple organ failure occurred in 60/80 patients (75.0%), and the overall mortality was 26/80 (32.5%). Concerning the LT-alpha-genotypes, there was no difference in the frequency of severe sepsis or shock or in the development of multi-organ failure or death between the three subgroups. The peak plasma TNF-alpha levels were similar for all genotype subgroups.

CONCLUSIONS

There was no correlation between the biallelic LT-alpha (+250 G/A) polymorphism and the outcome of critically ill patients. Genotyping this locus does not seem to be useful in predicting sepsis outcome.

Surgical trauma: hyperinflammation versus immunosuppression?

BACKGROUND

Experimental and clinical studies have brought evidence that surgical trauma markedly affects the immune system, including both the specific and the non-specific immune response.

MATERIALS AND METHODS

This report reviews the present knowledge on the mechanisms of surgical trauma-induced immune dysfunction and outlines experimental and clinical approaches to find effective treatment strategies.

RESULTS

Major surgical trauma induces an early hyperinflammatory response, which is characterized by (1) pro-inflammatory tumour necrosis factor alpha (TNF), interleukin (IL)-1, and IL-6 cytokine release and (2) neutrophil activation and microvascular adherence, as well as (3) uncontrolled polymorphonuclear (PMN) and macrophage oxidative burst. The massive and continuous IL-6 release induces an acute phase response, but, more importantly, also accounts for the up-regulation of major anti-inflammatory mediators, such as prostaglandin (PG) E2, IL-10 and transforming growth factor (TGF)-ss. This results in surgical, trauma-induced, immunosuppression, as indicated by (1) monocyte deactivation, reflected by the lack of monocytic TNF- production upon lipopolysaccharide (LPS) stimulation, and (2) a shift of the Th1/Th2 ratio towards a Th2-dominated cytokine pattern. The imbalance between pro-inflammatory and anti-inflammatory cytokines and immuno-competent cells determines the phenotype of disease and should help the physician to compose the therapeutic strategy. In fact, recent clinical studies have shown that both the initial uncontrolled hyperinflammation and the continued cell-mediated immunosuppression represent primary targets to counteract post-surgery immune dysfunction. The balance between inflammatory and anti-inflammatory forces may be restored by interferon gamma (IFN-gamma) to counteract monocyte deactivation; the anti-inflammatory PGE2 may be inhibited by indomethacin to attenuate immunosuppression; or the initial hyperinflammation may be targeted by administration of anti-inflammatory substances, such as granulocyte colony-stimulating factor (G-CSF), hydoxyethyl starch, or pentoxifylline.

CONCLUSIONS

When drawing up the therapeutic regimen the physician should not consider hyperinflammation versus immunosuppression, but hyperinflammation and immunosuppression, aiming at restoring an appropriate mediator- and immune cell-associated balance.

Role of tumor necrosis factor receptor-1 in the death of retinal ganglion cells following optic nerve crush injury in mice

To assess the specific role of tumor necrosis factor (TNF) death receptor signaling in the induction of retinal ganglion cell (RGC) death, optic nerves of mice deficient for TNF receptor-1 (TNF-R1-/-) and control mice (C57BL/6J) were unilaterally subjected to crush injury. Counts of RGCs and their axons 6 weeks after the injury demonstrated that their loss was significantly less in TNF-R1-/- mice compared to controls. The most prominent decrease in neuronal loss detected in TNF-R1-/- mice was beyond the initial 2-week period after the injury. This time period was correlated with the period of glial activation and increased glial immunolabeling for TNF-alpha in these eyes. No further protection against neuronal loss was detectable in TNF-R1-/- mice treated with D-JNKI1, a specific inhibitor of c-Jun N-terminal protein kinase (JNK). However, anti-JNK treatment of control animals provided a significant protection against neuronal loss during the same secondary degeneration period. Phospho-JNK immunolabeling of RGCs in control mice subjected to optic nerve crush significantly decreased following their treatment with D-JNKI1, and anti-JNK treatment protected RGCs from degeneration in these animals, similar to the lack of TNF-R1. These findings provide evidence that TNF death receptor signaling is involved in the secondary degeneration of RGCs following optic nerve injury, and is associated with JNK signaling. Since secondarily degenerating neurons are viable targets for neuroprotection, inhibition of TNF death receptor signaling may be an effective strategy to protect RGCs in several neurodegenerative injuries.

Immunologic Alterations Associated with High Blood Transfusion Volume After Multiple Injury: Effects on Plasmatic Cytokine and Cytokine Receptor Concentrations

The initial transfusion therapy after trauma has been identified as an independent risk factor for the incidence of multiple organ failure (MOF). Late occurrence of MOF in severely injured patients may be a clinical consequence of disturbed mediator homeostasis. For this reason, levels of interleukin (IL)-6, IL-10, and soluble tumor necrosis factor receptors (sTNFR) p55 and p75 were analyzed in the plasma of patients with comparable injury severity but with a different supply of packed red blood cells (PRBC). Thirty-eight multiple trauma patients with an injury severity score range of 25-54 points were separated into two groups according to their PRBC supply within the first 24 h after trauma. Patients who received at least 15 units of PRBC were analyzed in group 2 (n = 11); the remaining patients (n = 27) were assigned to group 1. The incidence of MOF was higher (P < 0.05) in group 2 patients. Correspondingly, levels of all assayed mediators were found significantly elevated at several time points in this patient group. We conclude that increases in mediator concentrations may be causally related to the extent of blood transfusion therapy itself or to the conditions for which it was needed.

Surgical sepsis: dysregulation of immune function and therapeutic implications

Sepsis is defined clinically as the systemic inflammatory response of the host to the documented systemic infection. The pathophysiological disturbance involves both the innate and adaptive immune systems encompassing cellular immunity, humoral components and the complement system. Dendritic cells (antigen-presenting cells) are key cells involved in the regulation of the immune response in sepsis, in particular in activating T cells and especially inducing the production and secretion of specific cytokines. These are the main mediators in establishing prominent disturbances of inflammation in patients with sepsis. The clinical features of the sepsis syndrome may vary from minor clinical disturbances to severe multiple organ failure and death of the host. Appropriate therapeutic strategies for patients with sepsis utilise conventional therapy and new novel forms of treatment, which are showing promise for the future.

Current concepts of the inflammatory response after major trauma: an update

During the past century explosive developments have taken place in the field of molecular medicine and genetics, vastly expanding our understanding of the normal physiological response to injury. We have been able to characterise specific molecular and cell biological processes and apply some of this knowledge to the treatment of multiply injured patients. Despite the significant steps we have made, there still remains much work to be done in this area. This review article highlights the current concepts of post-traumatic immunological changes and their impact in the management of trauma patients.

Systemic inflammatory response secondary to abdominal compartment syndrome: stage for multiple organ failure

BACKGROUND

The abdominal compartment syndrome (ACS) has been implicated in the pathogenesis of postinjury multiple organ failure. The ACS is defined as intra-abdominal hypertension causing adverse physiologic response. This study was designed to determine the effects of IAH on the production of interleukin-1b (IL-1beta), interleukin-6 (IL-6), tumor necrosis factor (TNF-alpha), and the effects on remote organ injury.

METHODS

IAH was induced in Sprague-Dawley rats which were divided into 5 groups, 10 animals each. Intra-abdominal pressure (IAP) was increased to 20 mm Hg for 60 and 90 minutes in two different groups. In a third group following IAP of 20 mm Hg the abdomen was decompressed for 30 minutes before samples were collected. The other animals were used as controls. Hemodynamic response was monitored throughout the procedure. Cytokine levels were assessed in the plasma. Remote organ injury was assessed by histopathology and myeloperoxidase activity.

RESULTS

IAH caused a significant decrease in MAP. After abdominal decompression MAP returned to baseline levels. A significant decrease in arterial pH was also noted. Increase in the levels of TNF-alpha and IL-6 was noted 30 minutes after abdominal decompression. Plasma concentration of IL-1b was elevated after 60 minutes of IAH. Abdominal decompression, however, did not cause a significant increase in the levels of this cytokine. Lung neutrophil accumulation was significantly elevated only after abdominal decompression. Histopathological findings showed intense pulmonary inflammatory infiltration including atelectasis and alveolar edema.

CONCLUSIONS

IAH provokes the release of pro-inflammatory cytokines which may serve as a second insult for the induction of MOF.

Glutamine-enriched enteral nutrition increases HLA-DR expression on monocytes of trauma patients

The aim of this study was to investigate the effect of glutamine-(Gln)-enriched enteral nutrition (EN) on human leukocyte antigen (HLA)-DR and FcgammaR1/CD64 expression on monocytes and plasma glutamine concentrations in multi-trauma patients. HLA-DR expression on monocytes is crucial in the presentation of foreign antigen to the immune system and is severely reduced in trauma patients. In vitro monocyte HLA-DR and FcgammaRI/CD64 expression is dependent on glutamine availability. To study the effect of glutamine supplemented enteral nutrition on HLA-DR and FcgammaRI/CD64 expression on CD14(+) monocytes, 55 multi-trauma patients were studied in a randomized, double-blinded, controlled trial. Trauma patients received either a Gln-enriched EN (glutamine group, n = 28) or an isocaloric, isonitrogenous control EN (control group, n = 27) and were compared with a group of age-matched healthy volunteers (healthy volunteers, n = 53). On d 1, 5, 9 and 14 after trauma, expressions of HLA-DR and FcgammaRI/CD64 were determined on CD14(+) monocytes using FACS analysis. Plasma glutamine levels were measured using HPLC. Plasma glutamine was lower in both trauma patient groups compared with healthy volunteers and from d 3 to d 5; glutamine was higher in the glutamine group than in the control group. On d 1, HLA-DR expression was much lower in both trauma patient groups than in healthy volunteers. HLA-DR expression was greater on d 5, 9 and 14 in the glutamine group than in the control group. FcgammaRI/CD64 expression on monocytes of trauma patients was not different than the expression of healthy volunteers. This study showed that glutamine-enriched enteral nutrition was associated with a higher HLA-DR expression on CD14(+) monocytes of trauma patients. No difference in monocyte FcgammaRI/CD64 expression was detected between patients that received the two enteral diets and between trauma patients and the healthy volunteers. Increased HLA-DR expression may improve cellular immune function and may be involved in the beneficial effect of glutamine on the occurrence of infections in trauma patients.

Long-term stable cultures of rat hepatocytes: an in vitro model to study acute and chronic hepatic inflammation

Engineered tissues provide an opportunity to investigate important physiological processes difficult to study in whole perfused organs and animal models. For example, a hepatocyte culture model consisting of rat hepatocytes cultured in a collagen sandwich configuration, which exhibits stable differentiated liver-specific functions, may be useful to investigate liver pathophysiology. To investigate systemic inflammation-related hepatic failure, we chronically exposed hepatocytes to the inflammatory mediators interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) for up to 4 weeks. IL-6 (2.5 ng/mL) transiently suppressed albumin (-90%) and chronically increased fibrinogen (+6-fold) production. IL-6 inhibited urea synthesis at 2.5 ng/mL and stimulated it at 0.025 ng/mL. IL-1beta (10 ng/mL) inhibited albumin (-90%), urea (-40 to 50%), and IL-6-stimulated fibrinogen (-90%) secretion. The inhibitory effect of IL-1beta on urea secretion was dose-dependent. Furthermore, IL-1beta transiently stimulated nitric oxide (NO) synthesis; however, NO did not mediate the effect of IL-1beta on albumin and fibrinogen production, and played a minor role in IL-1beta-mediated urea synthesis suppression. In conclusion, IL-1beta and IL-6 exert, via a direct effect on hepatocytes, long-term inhibitory effects on hepatic functions that are potentially important for the survival of the host, which may contribute to hepatic dysfunction in prolonged inflammatory states.

Association between injury pattern of patients with multiple injuries and circulating levels of soluble tumor necrosis factor receptors, interleukin-6 and interleukin-10, and polymorphonuclear neutrophil elastase

BACKGROUND

Our knowledge about the bidirectional interactions between brain and whole organism after trauma is still limited. It was the purpose of this prospective clinical study to determine the influence of severe head trauma (SHT) as well as trauma in different anatomic injury regions on posttraumatic inflammatory mediator levels from patients with multiple injuries.

METHODS

Thirty-five healthy controls, 33 patients with an isolated SHT, 47 patients with multiple injuries without SHT, and 45 patients with both SHT and multiple injuries were studied. The posttraumatic plasma levels of soluble tumor necrosis factor receptors p55 and p75, interleukin (IL)-6, IL-10, and polymorphonuclear neutrophil (PMN) elastase were monitored using enzyme-linked immunosorbent assay technique. The influence of head injuries as well as thorax, abdomen, and extremity injuries on the mediator release from patients with multiple injuries was investigated by multivariate linear regression models.

RESULTS

The soluble tumor necrosis factor receptor p55/p75 ratio was significantly elevated within 3 hours of trauma in all three injury groups and returned to reference ratios after 12 hours. The lowest increase was found in patients suffering from an isolated SHT. Lowest mediator levels in this patient population were also found for IL-6, IL-10, and PMN elastase during the first 36 hours after trauma. Additional injuries to the head, thorax, abdomen, and extremity modulated mediator levels to a different degree. No specific effect was found for SHT when compared with other injury groups. Thorax injuries caused the quickest rise in mediator levels, whereas abdominal injuries significantly increased PMN elastase levels 12 to 24 hours after trauma.

CONCLUSION

Traumatic injuries cause the liberation of various mediators, without any specific association between anatomic injury pattern and the pattern of mediator release.