Early immunologic responses to trauma in the emergency department patients with major injuries

Extrathoracic multiple trauma dysregulates neutrophil function and exacerbates pneumonia-induced lung injury

BACKGROUND

Forty percent of critically ill trauma patients will develop an infectious complication. Pneumonia is the most common cause of death of trauma patients surviving their initial insult. We previously demonstrated that polytrauma (PT), defined as two or more severe injuries in at least two areas of the body, induces emergency hematopoiesis characterized by accelerated myelopoiesis in the bone marrow and increased myeloid cell frequency in the peripheral tissues. We hypothesized that PT alone induces priming of neutrophils, resulting in hyperactivation upon secondary exposure to bacteria and causing acute lung injury and increased susceptibility to secondary exposure to Pseudomonas aeruginosa pneumonia.

METHODS

C57BL/6 mice were subjected to PT consisting of a lower extremity pseudofracture, liver crush injury, and 15% blood-volume hemorrhage. Pneumonia was induced by intratracheal injection of 5 × 106 CFU live P. aeruginosa or 1 × 107 of heat-killed P. aeruginosa (HKPA). For reactive oxygen species (ROS), studies polymorphonuclear neutrophils (PMNs) were isolated by immunomagnetic bead negative selection and stimulated ex-vivo with HKPA. Reactive oxygen species production was measured by immunofluorescence. For histology, lung sections were stained by hematoxylin-eosin and analyzed by a blinded grader.

RESULTS

Polytrauma induced persistent changes in immune function at baseline and to secondary infection. Pneumonia after injury resulted in increased mortality (60% vs. 5% p < 0.01). Blood neutrophils from PT mice had higher resting (unstimulated) ROS production than in naive animals (p < 0.02) demonstrating priming of the neutrophils following PT. After intratracheal HKPA injection, bronchoalveolar lavage PMNs from injured mice had higher ROS production compared with naive mice (p < 0.01), demonstrating an overexuberant immunopathologic response of neutrophils following PT.

CONCLUSION

Polytrauma primes neutrophils and causes immunopathologic PMN ROS production, increased lung injury and susceptibility to secondary bacterial pneumonia. These results suggest that trauma-induced immune dysfunction can cause immunopathologic response to secondary infection and suggests neutrophil-mediated pulmonary damage as a therapeutic target for posttrauma pneumonia.

Trauma results in immune cell-induced intestinal epithelial damage with subsequently increased sepsis rate

BACKGROUND

The detrimental effect of trauma on the immune system has been a subject of interest for decades. The gut-associated lymphoid tissue (GALT) of the bowel that encompasses different lymphocyte subpopulations may be an important pillar of human immunity in the context of trauma. Neither the short-term histological trauma-induced changes in the GALT nor its impact on the outcome after trauma surgery has been investigated.

METHODS

This prospective, longitudinal proof-of-concept study included patients who required damage-control surgery after abdominal gunshot wounds with small bowel involvement. Bowel specimens were obtained during the index and relook operations, and the T-lymphocytic quantity therein was analyzed via immunohistochemistry. We scrutinized how the lymphocyte structure and numbers of the GALT altered, and whether the extent and nature of these changes had an impact on the postoperative outcome with regard to septic and surgical complications.

RESULTS

A total of 31 damage-control patients were recruited for the study. The main histological changes between the index and relook specimen was a shift of CD8+ T cells from the lamina propria (LP) into the epithelium and a decrease of T lymphocytes in the LP. The significant increase of the intraepithelial CD8+ T cells was associated with a more extensive enterocyte apoptosis, and correlated significantly, positively with the number of postoperative septic complications.

CONCLUSION

Our data support that trauma induces an immune cell-driven impairment of the intestinal epithelium, as well as an increased apoptosis of lymphocytes in the LP, which is associated with a worse clinical outcome. The underlying mechanism suggests that a therapeutic approach to minimize apoptosis in the intestine may impact the outcome of severely injured trauma patients.

LEVEL OF EVIDENCE

Therapeutic/care/management, level lV.

The effect of fluid resuscitation strategy on monocyte and T-cell surface markers

BACKGROUND

Despite initial lifesaving benefits, posttraumatic resuscitation strategies have been associated with immunologic complications leading to systemic inflammatory response syndrome, sepsis, multiple organ failure, and late trauma death. Nevertheless, the direct effect on immunologic surface markers remains inadequately described. We hypothesized that changes in monocyte and T-cell surface markers were associated with initial posttraumatic fluid resuscitation.

MATERIALS AND METHODS

Data were extracted from the inflammation and host response to injury (Glue Grant) study. Blood samples were drawn from 492 patients on days 0, 1, 4, 7, 14, and 28 and analyzed for 31 monocyte and T-cell surface markers. Resuscitation strategies during the initial 48 h were quantified, including transfusion of packed red blood cells (PRBCs), fresh frozen plasma (FFP), platelets, and crystalloids. Longitudinal surface marker concentration changes were quantified by the calculation of a within-patient signal intensity change and were associated with resuscitation strategy while controlling confounders. P-values were post hoc corrected using the false detection rate q-value.

RESULTS

The monocyte surface marker (CD83) trajectory (as measured by a within-patient signal intensity change) was found to be positively associated with volume of PRBCs transfused (q = 0.002) and negatively associated with the transfused volume of FFP (q = 0.004). T-cell surface marker (CD3) was found to be negatively associated with volume of PRBCs transfused (q = 854 × 10-9) and positively associated with the transfused volume of FFP (q = 0.022). Platelets and crystalloid transfusion volumes were not associated with any surface marker trajectories.

CONCLUSIONS

PRBC and FFP transfusion was associated with opposing effects on CD3 and CD83 trajectories, which may in part explain some of the protective effects of a high FFP:PRBC ratio in trauma-related resuscitation.

Values of detection of NF-κB activation level combined with IL-6 and TNF-α levels in peripheral neutrophils in the prediction of multiple organ dysfunction syndrome in patients with severe multiple trauma

The aim of this study was to analyze the dynamic changes and predictive values of nuclear factor-κB (NF-κB) combined with interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in peripheral blood in multiple organ dysfunction syndrome (MODS) in patients with severe multiple trauma. Seventy patients diagnosed with severe multiple trauma in Emergency Department of Sichuan Provincial People's Hospital (Chengdu, China) from April 2014 to April 2016 were selected and retrospectively analyzed. The patients enrolled were divided into the MODS group (n=25) and the non-MODS group (n=45). The injury severity scores (ISSs), acute physiology and chronic health evaluation II (APACHE II) scores, NF-κB, IL-6 and TNF-α levels in patients were detected at different time points (12, 24 and 48 h after admission), the changes in different indexes and the areas under the receiver operating characteristic (ROC) curve (AUC) were analyzed. The predictive values of different detection methods in MODS patients were discussed and compared. The ISS, APACHE II score, NF-κB, IL-6 and TNF-α levels in the MODS group at admission and 24 and 48 h after admission were higher than those in the non-MODS group (P<0.05). Those indexes in the deceased patients at 12, 24 and 48 h after admission were higher than those in survivors (P<0.05). The ISS, APACHE II score, NF-κB, IL-6 and TNF-α levels were not the risk factors of MODS in patients with severe multiple trauma (P>0.05). AUCs of ISS >22 points and APACHE II score >14 points in predicting MODS were lower than that of combined detection of NF-κB >1.20. In conclusion, the combined detection of NF-κB, IL-6 and TNF-α in peripheral blood of patients with acute multiple trauma is more helpful to predict the occurrence of MODS, which has a certain guiding significance for the prognosis of patients with MODS.

Signatures of inflammation and impending multiple organ dysfunction in the hyperacute phase of trauma: A prospective cohort study

BACKGROUND

Severe trauma induces a widespread response of the immune system. This "genomic storm" can lead to poor outcomes, including Multiple Organ Dysfunction Syndrome (MODS). MODS carries a high mortality and morbidity rate and adversely affects long-term health outcomes. Contemporary management of MODS is entirely supportive, and no specific therapeutics have been shown to be effective in reducing incidence or severity. The pathogenesis of MODS remains unclear, and several models are proposed, such as excessive inflammation, a second-hit insult, or an imbalance between pro- and anti-inflammatory pathways. We postulated that the hyperacute window after trauma may hold the key to understanding how the genomic storm is initiated and may lead to a new understanding of the pathogenesis of MODS.

METHODS AND FINDINGS

We performed whole blood transcriptome and flow cytometry analyses on a total of 70 critically injured patients (Injury Severity Score [ISS] ≥ 25) at The Royal London Hospital in the hyperacute time period within 2 hours of injury. We compared transcriptome findings in 36 critically injured patients with those of 6 patients with minor injuries (ISS ≤ 4). We then performed flow cytometry analyses in 34 critically injured patients and compared findings with those of 9 healthy volunteers. Immediately after injury, only 1,239 gene transcripts (4%) were differentially expressed in critically injured patients. By 24 hours after injury, 6,294 transcripts (21%) were differentially expressed compared to the hyperacute window. Only 202 (16%) genes differentially expressed in the hyperacute window were still expressed in the same direction at 24 hours postinjury. Pathway analysis showed principally up-regulation of pattern recognition and innate inflammatory pathways, with down-regulation of adaptive responses. Immune deconvolution, flow cytometry, and modular analysis suggested a central role for neutrophils and Natural Killer (NK) cells, with underexpression of T- and B cell responses. In the transcriptome cohort, 20 critically injured patients later developed MODS. Compared with the 16 patients who did not develop MODS (NoMODS), maximal differential expression was seen within the hyperacute window. In MODS versus NoMODS, 363 genes were differentially expressed on admission, compared to only 33 at 24 hours postinjury. MODS transcripts differentially expressed in the hyperacute window showed enrichment among diseases and biological functions associated with cell survival and organismal death rather than inflammatory pathways. There was differential up-regulation of NK cell signalling pathways and markers in patients who would later develop MODS, with down-regulation of neutrophil deconvolution markers. This study is limited by its sample size, precluding more detailed analyses of drivers of the hyperacute response and different MODS phenotypes, and requires validation in other critically injured cohorts.

CONCLUSIONS

In this study, we showed how the hyperacute postinjury time window contained a focused, specific signature of the response to critical injury that led to widespread genomic activation. A transcriptomic signature for later development of MODS was present in this hyperacute window; it showed a strong signal for cell death and survival pathways and implicated NK cells and neutrophil populations in this differential response.

Total knee replacement induces peripheral blood lymphocytes apoptosis and it is not prevented by regional anesthesia - a randomized study

BACKGROUND

Among the many changes caused by a surgical insult one of the least studied is postoperative immunosuppression. This phenomenon is an important cause of infectious complications of surgery such as surgical site infection or hospital acquired pneumonia. One of the mechanisms leading to postoperative immunosuppression is the apoptosis of immunological cells. Anesthesia during surgery is intended to minimize harmful changes and maintain perioperative homeostasis. The aim of the study was evaluation of the effect of the anesthetic technique used for total knee replacement on postoperative peripheral blood lymphocyte apoptosis.

METHODS

34 patients undergoing primary total knee replacement were randomly assigned to two regional anesthetic protocols: spinal anesthesia and combined spinal-epidural anesthesia. 11 patients undergoing total knee replacement under general anesthesia served as control group. Before surgery, immediately after surgery, during first postoperative day and seven days after the surgery venous blood samples were taken and the immunological status of the patient was assessed with the use of flow cytometry, along with lymphocyte apoptosis using fluorescent microscopy.

RESULTS

Peripheral blood lymphocyte apoptosis was seen immediately in the postoperative period and was accompanied by a decrease of the number of T cells and B cells. There were no significant differences in the number of apoptotic lymphocytes according to the anesthetic protocol. Changes in the number of T CD3/8 cells and the number of apoptotic lymphocytes were seen on the seventh day after surgery.

CONCLUSION

Peripheral blood lymphocyte apoptosis is an early event in the postoperative period that lasts up to seven days and is not affected by the choice of the anesthetic technique.

[Total knee replacement induces peripheral blood lymphocytes apoptosis and it is not prevented by regional anesthesia - a randomized study]

BACKGROUND

Among the many changes caused by a surgical insult one of the least studied is postoperative immunosuppression. This phenomenon is an important cause of infectious complications of surgery such as surgical site infection or hospital acquired pneumonia. One of the mechanisms leading to postoperative immunosuppression is the apoptosis of immunological cells. Anesthesia during surgery is intended to minimize harmful changes and maintain perioperative homeostasis. The aim of the study was evaluation the effect of the anesthetic technique used for total knee replacement on postoperative peripheral blood lymphocyte apoptosis.

METHODS

34 patients undergoing primary total knee replacement were randomly assigned to two regional anesthetic protocols: spinal anesthesia and combined spinal-epidural anesthesia. 11 patients undergoing total knee replacement under general anesthesia served as control group. Before surgery, immediately after surgery, during first postoperative day and seven days after the surgery venous blood samples were taken and the immunological status of the patient was assessed with the use of flow cysts 87 m, along with lymphocyte apoptosis using fluorescent microscopy.

RESULTS

Peripheral blood lymphocyte apoptosis was seen immediately in the postoperative period and was accompanied by a decrease of the number of T cells and B cells. There were no significant differences in the number of apoptotic lymphocytes according to the anesthetic protocol. Changes in the number of T CD3/8 cells and the number of apoptotic lymphocytes were seen on the seventh day after surgery.

CONCLUSION

Peripheral blood lymphocyte apoptosis is an early event in the postoperative period lasts up to seven days and is not affected by the choice of the anesthetic technique.

Decreased levels of perforin-positive lymphocytes are associated with posttraumatic complications in patients with major trauma

OBJECTIVE

Posttraumatic immune disorder can cause complications including systemic inflammatory response syndrome (SIRS) and multiple-organ dysfunction syndrome (MODS). Cytotoxic granules containing perforin and granzyme-B (GrB) are released by cytotoxic CD8(+) T lymphocytes, NK and γδT cells after major trauma. This prospective clinical study was designed to analyze the association between these immune components and complications after major trauma.

METHODS

We retrospectively studied 48 patients aged between 16 and 65 years admitted within 90min of major trauma (Injury Severity Score>16) and surviving beyond 7 days, and 20 healthy controls. Blood samples were drawn on admission and after 1, 3 and 7 days. CD8(+) T, NK and γδT cell counts in peripheral blood and the levels of perforin and GrB in these cells were analyzed by flow cytometry. Clinical aspects of MODS and SIRS were recorded daily.

RESULTS

CD8(+) T cell counts were not significantly different in patients with SIRS or uncomplicated group, but were depressed in the MODS group after trauma. However, NK cell counts in patients with MODS were significantly depressed only at day 7 after injury, and γδT cell counts were significantly depressed after trauma. Perforin levels in CD8(+) T, NK and γδT cells in patients with MODS were depressed after trauma. GrB levels in NK, CD8(+) T and γδT cells in patients with MODS were significantly depressed at 3 and 7 days post trauma.

CONCLUSION

Posttraumatic MODS is associated with early, sustained, and severe depression of lymphocytes.

Peri-operative changes in serum immune markers after trauma: a systematic review

INTRODUCTION

Surgery is a posttraumatic immune stimulus which contributes to the systemic inflammatory response syndrome and multiple organ failure (MOF). Serum markers may facilitate post-injury immune monitoring, predict complications and guide the timing of surgery.

AIM

To evaluate whether immune markers increase after surgery in trauma patients, if this is affected by the timing of surgery, and whether immune markers correlate with clinical outcomes.

PATIENTS AND METHODS

Systematic review of MEDLINE, Cochrane and EMBASE using a combination of keywords including trauma, biological markers, immune monitoring, and surgical procedures. The last search was performed on 26/11/13. The search considered English language studies enrolling adult trauma patients. Outcomes were perioperative immune markers plus clinical outcomes including mortality, MOF, sepsis.

RESULTS

1612 Articles were identified using the search strategy. 1548 Articles were excluded by title and 40 excluded by abstract, leaving 24 articles for full text review. Of these articles, fifteen studies were eligible for study inclusion. The disparity in interventions and outcome measures precluded combined statistical analysis. The surgical intervention studied was mostly intramedullary nailing of long bone fractures. All articles described a postoperative increase in at least one marker. Interleukin (IL)-6 and IL-10 were consistently elevated and tested in the greatest number of patients. Many studies did not correlate markers with clinical outcomes and few significant associations were demonstrated. Two studies considered the timing of surgery and showed greater increase in IL-6 after "early" surgery, though definitions of timing were dissimilar.

DISCUSSION

An increase in posttraumatic serum cytokines has been demonstrated after surgery, but without consistent clinical associations. The timing of surgery may modulate this increase. Future research directions include confirmation of findings in larger populations, clarifying clinical associations, and evaluation of other surgical interventions.

Systemic release of cytokines and heat shock proteins in porcine models of polytrauma and hemorrhage*

OBJECTIVE

To define systemic release kinetics of a panel of cytokines and heat shock proteins in porcine polytrauma/hemorrhage models and to evaluate whether they could be useful as early trauma biomarkers.

DESIGN

Prospective observational study.

SETTING

Research laboratory.

SUBJECTS

Twenty-one Yorkshire pigs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Pigs underwent polytrauma (femur fractures/lung contusion, P), hemorrhage (mean arterial pressure 25-30 mm Hg, H), polytrauma plus hemorrhage (P/H), or sham procedure (S). Plasma was obtained at baseline, in 5- to 15-min intervals during a 60-min shock period without intervention, and in 60- to 120-min intervals during fluid resuscitation for up to 300 min. Plasma was assayed for interleukin-1β, interleukin-4, interleukin-5, interleukin-6, interleukin-8, interleukin-10, interleukin-12/interleukin-23p40, interleukin-13, interleukin-17, interleukin-18, interferonγ, transforming growth factor-β, tumor necrosis factor-α, heat shock protein 40, heat shock protein 70, and heat shock protein 90 by enzyme-linked immunosorbent assay. All animals after S, P, and H survived (n = 5/group). Three of six animals after P/H died. Interleukin-10 increased during shock after P and this increase was attenuated after H. Tumor necrosis factor-α increased during the shock period after P, H, and also after S. P/H abolished the systemic interleukin-10 and tumor necrosis factor-α release and resulted in 20% to 30% increased levels of interleukin-6 during shock. As fluid resuscitation was initiated, tumor necrosis factor-α and interleukin-10 levels decreased after P, H, and P/H; heat shock protein 70 increased after P; and interleukin-6 levels remained elevated after P/H and also increased after P and S.

CONCLUSIONS

Differential regulation of the systemic cytokine release after polytrauma and/or hemorrhage, in combination with the effects of resuscitation, can explain the variability and inconsistent association of systemic cytokine/heat shock protein levels with clinical variables in trauma patients. Insults of major severity (P/H) partially suppress the systemic inflammatory response. The plasma concentrations of the measured cytokines/heat shock proteins do not reflect injury severity or physiological changes in porcine trauma models and are unlikely to be able to serve as useful trauma biomarkers in patients.

Recombinant factor XIII mitigates hemorrhagic shock-induced organ dysfunction

BACKGROUND

Plasma factor XIII (FXIII) is responsible for stabilization of fibrin clot at the final stage of blood coagulation. Since FXIII has also been shown to modulate inflammation, endothelial permeability, as well as diminish multiple organ dysfunction (MOD) after gut ischemia-reperfusion injury, we hypothesized that FXIII would reduce MOD caused by trauma-hemorrhagic shock (THS).

MATERIALS AND METHODS

Rats were subjected to a 90 min THS or trauma sham shock (TSS) and treated with either recombinant human FXIII A(2) subunit (rFXIII) or placebo immediately after resuscitation with shed blood or at the end of the TSS period. Lung permeability, lung and gut myeloperoxidase (MPO) activity, gut histology, neutrophil respiratory burst, microvascular blood flow in the liver and muscles, and cytokine levels were measured 3 h after the THS or TSS. FXIII levels were measured before THS or TSS and after the 3-h post-shock period.

RESULTS

THS-induced lung permeability as well as lung and gut MPO activity was significantly lower in rFXIII-treated than in placebo-treated animals. Similarly, rFXIII-treated rats had lower neutrophil respiratory burst activity and less ileal mucosal injury. rFXIII-treated rats also had a higher liver microvascular blood flow compared with the placebo group. Cytokine response was more favorable in rFXIII-treated animals. Trauma-hemorrhagic shock did not cause a drop in FXIII activity during the study period.

CONCLUSIONS

Administration of rFXIII diminishes THS-induced MOD in rats, presumably by preservation of the gut barrier function, limitation of polymorphonuclear leukocyte (PMN) activation, and modulation of the cytokine response.