Monotrauma is associated with enhanced remote inflammatory response and organ damage, while polytrauma intensifies both in porcine trauma model

Rate of Complications after Hip Fractures Caused by Prolonged Time-to-Surgery Depends on the Patient's Individual Type of Fracture and Its Treatment

INTRODUCTION

Hip fractures are common injuries in the elderly and are usually treated with timely surgery. While severe postoperative complications are reported for up to 10% of patients, many studies identified predictive factors for the occurrence of complications postoperatively. A controversially discussed factor is "time-to-surgery". The aim of the study was to examine if time-to-surgery was associated with the occurrence of complications and if the complication rate differed between the patient individual fracture types of intracapsular on the one hand and extracapsular hip fractures on the other hand. We hypothesized that time-to-surgery had less impact on complications in intracapsular hip fractures compared to extracapsular ones, and therefore, guidelines should pay attention to the patient individual case scenario.

MATERIALS AND METHODS

All patients who were admitted to the Department of Trauma and Orthopaedic Surgery of an academic teaching hospital for hip fracture surgery (n = 650) over a five-year period were included in the study. After the application of the exclusion criteria, such as periprosthetic or pathologic fractures, cases needed immediate surgical treatment, and after outlier adjustment, 629 cases remained in the study. Hip fractures were classified into intracapsular fractures (treated by hip arthroplasty) and extracapsular fractures (treated by intramedullary nailing osteosynthesis). The occurrence of severe complications in patients treated within 24 h was compared with patients treated later than 24 h after injury. For statistical evaluation, a multivariate logistic regression analysis was performed to investigate the impact of time-to-surgery interval on the occurrence of complications.

RESULTS

Patients with an extracapsular fracture, which was treated with intramedullary nailing (44.5%), rarely suffered a serious complication when surgery was performed within 24 h after injury. However, when the interval of the time-to-surgery was longer than 24 h, the complication rate increased significantly (8.63% vs. 25.0%, p = 0.002). In contrast to this finding in patients with intracapsular fractures (55.5%), which were treated with cemented arthroplasty, complication rates did not depend on the 24 h interval (26.17% vs. 20.83%, p = 0.567).

CONCLUSIONS

The occurrence of complications after surgical treatment of hip fractures is associated with the time interval between injury and surgery. A 24 h time interval between injury and surgical procedure seems to play a major role only in extracapsular fractures treated with osteosynthesis but not in intracapsular fractures treated with arthroplasty. Therefore, guidelines should take notice of the patient individual case scenario and, in particular, the individual hip fracture type.

Impact of age on liver damage, inflammation, and molecular signaling pathways in response to femoral fracture and hemorrhage

Background

Trauma causes disability and mortality globally, leading to fractures and hemorrhagic shock. This can trigger an irregular inflammatory response that damages remote organs, including liver. Aging increases the susceptibility to dysregulated immune responses following trauma, raising the risk of organ damage, infections, and higher morbidity and mortality in elderly patients. This study investigates how aging affects liver inflammation and damage post-trauma.

Methods

24 male C57BL/6J mice were randomly divided into four groups. Twelve young (17-26 weeks) and 12 aged (64-72 weeks) mice were included. Mice further underwent either hemorrhagic shock (trauma/hemorrhage, TH), and femoral fracture (osteotomy) with external fixation (Fx) (THFx, n=6) or sham procedures (n=6). After 24 hours, mice were sacrificed. Liver injury and apoptosis were evaluated using hematoxylin-eosin staining and activated caspase-3 immunostaining. CXCL1 and infiltrating polymorphonuclear leukocytes (PMNL) in the liver were assessed by immunostaining, and concentrations of CXCL1, TNF, IL-1β, and IL-10 in the liver tissue were determined by ELISA. Gene expression of Tnf, Cxcl1, Il-1β, and Cxcl2 in the liver tissue was determined by qRT-PCR. Finally, western blot was used to determine protein expression levels of IκBα, Akt, and their phosphorylated forms.

Results

THFx caused liver damage and increased presence of active caspase-3-positive cells compared to the corresponding sham group. THFx aged group had more severe liver injury than the young group. CXCL1 and PMNL levels were significantly higher in both aged groups, and THFx caused a greater increase in CXCL and PMNL levels in aged compared to the young group. Pro-inflammatory TNF and IL-1β levels were elevated in aged groups, further intensified by THFx. Anti-inflammatory IL-10 levels were lower in aged groups. Tnf and Cxcl1 gene expression was enhanced in the aged sham group. Phosphorylation ratio of IκBα was significantly increased in the aged sham group versus young sham group. THFx-induced IκBα phosphorylation in the young group was significantly reduced in the aged THFx group. Akt phosphorylation was significantly reduced in the THFx aged group compared to the THFx young group.

Conclusion

The findings indicate that aging may lead to increased vulnerability to liver injury and inflammation following trauma due to dysregulated immune responses.

Cranial CT is a mandatory tool to exclude asymptomatic cerebral hemorrhage in elderly patients on anticoagulation

Background

Traumatic brain injury (TBI) after falls causes death and disability with immense socioeconomic impact through medical and rehabilitation costs in geriatric patients. Diagnosing TBI can be challenging due to the absence of initial clinical symptoms. Misdiagnosis is particularly dangerous in patients on permanent anticoagulation because minimal trauma might result in severe intracranial hemorrhage. The aim of this study is to evaluate the diagnostic necessity of cranial computed tomography (cCT) to rule out intracranial hemorrhage, particularly in the absence of neurologic symptoms in elderly patients on permanent anticoagulation in their premedication.

Patients and methods

Retrospective cohort analysis of elderly trauma patients (≥ 65 years) admitted to the emergency department (ED) of the level-1-trauma center of the University Hospital Frankfurt from 01/2017 to 12/2019. The study included patients who suffered a ground-level fall with suspected TBI and subsequently underwent CT because of preexisting anticoagulation.

Results

A total of 227 patients met the inclusion criteria. In 17 of these patients, cCT showed intracranial hemorrhage, of which 14 were subdural hematomas (SDH). In 8 of the patients with bleeding showed no clinical symptoms, representing 5% (n = 160) of all symptom-free patients. Men and women were equally to suffer a post-traumatic hemorrhage. Patients with intracranial bleeding were hospitalized for 14.5 (±10.4) days. Acetylsalicylic acid (ASA) was the most prescribed anticoagulant in both patient cohorts-with or without intracerebral bleeding (70.6 vs. 77.1%, p = 0.539). Similarly, patients taking new oral anticoagulant (NOAC) (p = 0.748), coumarins, or other platelet inhibitors (p > 0.1) did not show an increased bleeding incidence.

Conclusion

Acetylsalicylic acid and NOAC use are not associated with increased bleeding risk in geriatric trauma patients (≥ 65 years) after fall-related TBI. Even in asymptomatic elderly patients on anticoagulation, intracranial hemorrhage occurs in a relevant proportion after minor trauma to the head. Therefore, cCT is an obligatory tool to rule out cerebral hemorrhage in elderly patients under anticoagulation.

Pulmonary inflammatory response and immunomodulation to multiple trauma and hemorrhagic shock in pigs

BACKGROUND

Patients suffering from severe trauma experience substantial immunological stress. Lung injury is a known risk factor for the development of posttraumatic complications, but information on the long-term course of the pulmonary inflammatory response and treatment with mild hypothermia are scarce.

AIM

To investigate the pulmonary inflammatory response to multiple trauma and hemorrhagic shock in a porcine model of combined trauma and to assess the immunomodulatory properties of mild hypothermia.

METHODS

Following induction of trauma (blunt chest trauma, liver laceration, tibia fracture), two degrees of hemorrhagic shock (45 and 50%) over 90 (n = 30) and 120 min. (n = 20) were induced. Animals were randomized to hypothermia (33°C) or normothermia (38°C). We evaluated bronchoalveolar lavage (BAL) fluid and tissue levels of cytokines and investigated changes in microRNA- and gene-expression as well as tissue apoptosis.

RESULTS

We observed a significant induction of Interleukin (IL) 1β, IL-6, IL-8, and Cyclooxygenase-2 mRNA in lung tissue. Likewise, an increased IL-6 protein concentration could be detected in BAL-fluid, with a slight decrease of IL-6 protein in animals treated with hypothermia. Lower IL-10 protein levels in normothermia and higher IL-10 protein concentrations in hypothermia accompanied this trend. Tissue apoptosis increased after trauma. However, intervention with hypothermia did not result in a meaningful reduction of pro-inflammatory biomarkers or tissue apoptosis.

CONCLUSION

We observed signs of a time-dependent pulmonary inflammation and apoptosis at the site of severe trauma, and to a lower extent in the trauma-distant lung. Intervention with mild hypothermia had no considerable effect during 48 hours following trauma.

Evaluating the effect of montelukast tablets on respiratory complications in patients following blunt chest wall trauma: A double-blind, randomized clinical trial

PURPOSE

Patients with multiple traumas are at high risk of developing respiratory complications, including pneumonia and acute respiratory distress syndrome. Many pulmonary complications are associated with systemic inflammation and pulmonary neutrophilic infiltration. Leukotriene-receptor antagonists are anti-inflammatory and anti-oxidant drugs subsiding airway inflammation. The present study investigates the effectiveness of montelukast in reducing pulmonary complications among trauma patients.

METHODS

This randomized, double-blind, placebo-control trial was conducted in patients with multiple blunt traumas and evidence of lung contusion detected via CT scan. We excluded patients if they met at least one of the following conditions: <16 years old, history of cardiopulmonary diseases or positive history of montelukast-induced hypersensitivity reactions. Patients were allocated to the treatment (10 mg of montelukast) or placebo group using permuted block randomization method. The primary measured outcome was the volume of pulmonary contusion at the end of the trial. The secondary outcomes were intensive care unit and hospital length of stay, ventilation days, multi-organ failure, and the in-hospital mortality rate.

RESULTS

In total, 65 eligible patients (treatment = 31, placebo = 34) were included for the final analysis. The treatment group had more pulmonary contusion volume (mean (SD), mm³) at the right (68726.97 (93656.54) vs. 59730.27 (76551)) and the left side (67501.71 (91514) vs. 46502.21 (80604.21)), higher initial C-reactive peptide level (12.16 (10.58) vs. 10.85 (17.9)) compared to the placebo group, but the differences were not statistically significant (p > 0.05). At the end of the study, the mean (SD) of pulmonary contusion volume (mm³) (right side = 116748.74 (361705.12), left side = 64522.03 (117266.2)) of the treatment group were comparable to that of the placebo group (right side = 40051.26 (64081.56), left side = 25929.12 (47417.13), p = 0.228 and 0.082, respectively). Moreover, both groups have statistically similar hospital (mean (SD), days) (10.87 (9.83) vs. 13.05 (10.12)) and intensive care unit length of stays (mean (SD), days) (7.16 (8.15) vs. 7.82 (7.48)). Of note, the frequency of the in-hospital complications (treatment vs. control group) including acute respiratory distress syndrome (12.9% vs. 8.8%, p = 0.71), pneumonia (19.4% vs. 17.6%, p = 0.85), multi-organ failure (12.9% vs. 17.6%, p = 0.58) and the mortality rate (22.6% vs. 14.7%, p = 0.41) were comparable between the groups.

CONCLUSION

Administrating montelukast has no preventive or therapeutic effects on lung contusion or its complications.

Standardized porcine unilateral femoral nailing is associated with changes in PMN activation status, rather than aberrant systemic PMN prevalence

PURPOSE

Intramedullary nailing (IMN) of fractures is associated with increased rates of inflammatory complications. The pathological mechanism underlying this phenomenon is unclear. However, polymorphonuclear granulocytes (PMNs) seem to play an important role. We hypothesized that a femur fracture and standardized IMN in pigs is associated with altered appearance of PMNs in circulation and enhanced activation status of these cells.

METHODS

A porcine model including a femur fracture and IMN was utilized. Animals were randomized for control [anesthesia + mechanical ventilation only (A/MV)] and intervention [A/MV and unilateral femur fracture (FF) + IMN] conditions. PMN numbers and responsiveness, integrin (CD11b), L-selectin (CD62L) and Fcγ-receptor (CD16 and CD32)-expression levels were measured by flowcytometry of blood samples. Animals were observed for 72 h.

RESULTS

Circulatory PMN numbers did not differ between groups. Early PMN-responsiveness was retained after insult. PMN-CD11b expression increased significantly upon insult and peaked after 24 h, whereas CD11b in control animals remained unaltered (P = 0.016). PMN-CD16 expression levels in the FF + IMN-group rose gradually over time and were significantly higher compared with control animals, after 48 h (P = 0.016) and 72 h (P = 0.032). PMN-CD62L and CD32 expression did not differ significantly between conditions.

CONCLUSION

This study reveals that a femur fracture and subsequent IMN in a controlled setting in pigs is associated with enhanced activation status of circulatory PMNs, preserved PMN-responsiveness and unaltered circulatory PMN-presence. Indicating that monotrauma plus IMN is a specific and substantial stimulus for the cellular immune system. Early alterations of circulatory PMN receptor expression dynamics may be predictive for the intensity of the post traumatic response.

Neutralization of HMGB1 improves fracture healing and γδ T lymphocyte counts at the fracture site in a polytrauma rat model

Purpose

Delayed fracture healing is a common consequence of polytrauma (PT) occurring in patients with multiple injuries. We believe that when early release of high mobility group box 1 (HMGB1) molecules from necrotic tissues exceed their normal levels in blood, they dysregulate immune responses associated with normal healing. This study investigates the detrimental effect of such dysregulate immune responses by targeting HMGB1 in a PT rat model with debilitating injuries. We hypothesized that neutralization of extracellular HMGB1 immediately post-trauma would ameliorate local immune dysregulation and improve fracture healing in a PT rat model.

Methods

PT rats received a single dose of either anti-rat HMGB1 polyclonal antibody (PT-Ab HMGB1) or IgY isotype (PT-IgY), were left untreated (PT-C), or had a single injury/osteotomy only (OST). Fracture healing was evaluated by micro-computed tomography (µCT) and histology at 5 weeks; and macrophages and T cell counts within the fracture site were determined with flow cytometry  at 1 week.

Results

Notably, bone regeneration within the fracture site in PT-Ab HMGB1 rats was improved with comparable connective tissue organization than PT-C rats. Further, only γδTCR⁺ T cells, but not macrophages and CD4⁺ and CD8⁺ T cells, were diminished at the fracture site in PT-C and PT-IgY rats. Interestingly, the PT-Ab HMGB1 rats had increased γδTCR⁺ T cells compared to PT-C and PT-IgY, suggesting their potential role in regulating fracture healing.

Conclusions

Therefore, the initial burst of systemic HMGB1 following trauma may have a role in regulating bone regeneration via the modulation of a subclass of T cells within the fracture site, suggesting it’s importance as a therapeutic target in PT to combat immune dysregulation and delayed fracture healing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40634-022-00453-3.

Blast polytrauma with hemodynamic shock, hypothermia, hypoventilation and systemic inflammatory response: description of a new porcine model

PURPOSE

In the past decade blast injuries have become more prevalent. Blast trauma may cause extensive injuries requiring improved early resuscitation and prevention of haemorrhage. Randomized prospective trials are logistically and ethically challenging, and large animal models are important for further research efforts. Few severe blast trauma models have been described, which is why we aimed to establish a comprehensive polytrauma model in accordance with the criteria of the Berlin definition of polytrauma and with a survival time of > 2 h. Multiple blast injuries to the groin and abdomen were combined with hypoperfusion, respiratory and metabolic acidosis, hypoventilation, hypothermia and inflammatory response. The model was compared to lung contusion and haemorrhage.

METHODS

16 landrace swine (mean weight 60.5 kg) were randomized to "control" (n = 5), "chest trauma/hem" by lung contusion and class II haemorrhage (n = 5), and "blast polytrauma" caused by multiple blast injuries to the groin and abdomen, class II haemorrhage, lipopolysaccharide (LPS) infusion and hypothermia 32 °C (n = 6).

RESULTS

The blast polytrauma group had an Injury Severity Score of 57 which resulted in haemodynamic shock, hypothermia, respiratory and metabolic acidosis and inflammatory response. The chest trauma/hem group had an Injury Severity Score of 9 and less profound physiologic effects. Physiologic parameters presented a dose-response relationship corresponding to the trauma levels.

CONCLUSION

A comprehensive blast polytrauma model fulfilling the Berlin polytrauma criteria, with a high trauma load and a survival time of > 2 h was established. A severe, but consistent, injury profile was accomplished enabling the addition of experimental interventions in future studies, particularly of immediate resuscitation efforts including whole blood administration, trauma packing and haemostasis.

Influence of Antibiotic Management on Microbial Selection and Infectious Complications After Trauma

Background: The inflammatory response and post-traumatic complications like infections play an important role in the pathophysiology of severe injuries. This study examines the microbiological aspects in anti-infective treatment of trauma patients and their inflammatory response in post-traumatic infections complications.

Patients and Methods: A retrospective analysis of prospectively collected data in trauma patients (ISS ≥ 16) over a 1-year period (01/2018 to 12/2018) is provided. Patient population was stratified into severely injured patients without post-traumatic infection (inf-PT), and severely injured patients who developed an infection (inf+PT).

Results: Of 114 trauma patients, 45 suffered from post-traumatic infection during the first 10 days of hospitalization. Severely injured patients with concomitant traumatic brain injury (PT+TBI) showed the highest rate of post-traumatic infection. Pro-inflammatory reaction was tracked by levels of Interleukin (IL-)6 (day 3: inf+T 190.8 ± 359.4 pg/dL > inf-PT 56.2 ± 57.7 pg/mL (mean ± SD); p = 0.008) and C-Reactive-Protein (CRP, day 3: inf+PT 15.3 mg/dL > inf-PT 6.7 mg/dL, p = 0.001) which were significantly higher in trauma patients who develop an infectious complication and showed a significant positive correlation with the occurrence of infection. The leading entity of infection was pneumonia followed by infections of the urinary tract mainly caused by gram-negative Enterobacteriaceae. 67.5% of all trauma patients received single-shot antibiosis during initial care in trauma bay. The development of secondary colonization was not relevant positively correlated with single-shot antibiosis (r = 0.013, p = 0.895) and prophylactically calculated antibiotic administration (r = 0.066, p = 0.500).

Conclusion: Severely injured trauma patients have an increased risk for development of infectious complications, which mainly is pneumonia followed by infection of the urinary tract mainly caused by gram-negative Enterobacteriaceae. Based on the data in this study, the one-time antibiotic and prophylactic calculated use of antibiotics, like Cephalosporins must be critically discussed in terms of their role in the development of post-traumatic infections and microbial selection.

Quantitative Evaluation of Embolic Load in Femoral and Tibial Shaft Fractures Treated With Reamed Intramedullary Fixation

OBJECTIVES

To compare the volume of embolic load during intramedullary fixation of femoral and tibial shaft fractures. Our hypothesis was that tibial intramedullary nails (IMNs) would be associated with less volume of intravasation of marrow than IM nailing of femur fractures.

DESIGN

Prospective observational study.

SETTING

Urban Level I trauma center.

PATIENTS/PARTICIPANTS

Twenty-three patients consented for the study: 14 with femoral shaft fractures and 9 with tibial shaft fractures.

INTERVENTION

All patients underwent continuous transesophageal echocardiography, and volume of embolic load was evaluated during 5 distinct stages: postinduction, initial guide wire, reaming (REAM), nail insertion, and postoperative.

MAIN OUTCOME MEASUREMENTS

Volume of embolic load was measured based on previously described luminosity scores. The embolic load based on fracture location and procedure stage was evaluated using a mixed effects model.

RESULTS

The IMN procedure increased the embolic load by 215% (-12% to 442%, P = 0.07) in femur patients relative to tibia patients after adjusting for baseline levels. Of the 5 steps measured, REAM was associated with the greatest increase in embolic load relative to the guide wire placement and controlling for fracture location (421%, 95% confidence interval: 169%-673%, P < 0.01).

CONCLUSIONS

Femoral shaft IMN fixation was associated with a 215% increase in embolic load in comparison with tibial shaft IMN fixation, with the greatest quantitative load during the REAM stage; however, both procedures produce embolic load.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

What Is a Cytokine Storm and Should It Matter to Me?

The recent COVID-19 pandemic has brought attention to cytokines and the phenomenon of cytokine storm into mainstream discussions. In this disease specifically, a cytokine storm overwhelming immune response contributes to the pathophysiology and mortality of the COVID-19 infection. Analogous perturbed immune reactions are experienced in polytrauma patients, compromising local tissue healing while threatening multiple organ systems. The expanding field of osteoimmunology should contribute to the orthopaedic community's understanding of how the immune system response, whether normal or pathologic, affects the whole body outcome of our patients.

Club Cell Protein 16 Attenuates CD16brightCD62dim Immunosuppressive Neutrophils in Damaged Tissue upon Posttraumatic Sepsis-Induced Lung Injury

Background

Recently, identification of immunosuppressive polymorphonuclear leukocytes (PMNL) that were traditionally described as proinflammatory cells emerged in the field of posttraumatic immunity. To understand their local and remote distribution after trauma, PMNL-subsets and the impact of immunomodulatory Club Cell protein (CC)16 that correlates with pulmonary complications were assessed.

Methods

C57BL/6N mice were divided into three groups, receiving isolated blunt chest trauma (TxT), undergoing TxT followed by cecal ligation and puncture (CLP, TxT + CLP) after 24 h, or sham undergoing analgosedation (n = 18/group). Further, each group was subdivided into three groups receiving either no treatment (ctrl) or intratracheal neutralization of CC16 by application of anti-CC16-antibody or application of an unspecific IgG control antibody (n = 6/group). Treatment was set at the time point after TxT. Analyses followed 6 h post-CLP. PMNL were characterized via expression of CD11b, CD16, CD45, CD62L, and Ly6G by flow cytometry in bone marrow (BM), blood, spleen, lung, liver, and bronchoalveolar and peritoneal lavage fluid (BALF and PL). Apoptosis was assessed by activated (cleaved) caspase-3. Results from untreated ctrl and IgG-treated mice were statistically comparable between all corresponding sham, TxT, and TxT + CLP groups.

Results

Immature (CD16^dimCD62L^bright) PMNL increased significantly in BM, circulation, and spleen after TxT vs. sham and were significantly attenuated in the lungs, BALF, PL, and liver. Classical-shaped (CD16^brightCD62L^bright) PMNL increased after TxT vs. sham in peripheral tissue and were significantly attenuated in circulation, proposing a trauma-induced migration of mature or peripheral differentiation of circulating immature PMNL. Immunosuppressive (CD16^brightCD62L^dim) PMNL decreased significantly in the lungs and spleen, while they systemically increased after TxT vs. sham. CLP in the TxT + CLP group reduced immunosuppressive PMNL in PL and increased their circulatory rate vs. isolated TxT, showing local reduction in affected tissue and their increase in nonaffected tissue. CC16 neutralization enhanced the fraction of immunosuppressive PMNL following TxT vs. sham and decreased caspase-3 in the lungs post-CLP in the TxT + CLP group, while apoptotic cells in the liver diminished post-TxT. Posttraumatic CC16 neutralization promotes the subset of immunosuppressive PMNL and antagonizes their posttraumatic distribution.

Conclusion

Since CC16 affects both the distribution of PMNL subsets and apoptosis in tissues after trauma, it may constitute as a novel target to beneficially shape the posttraumatic tissue microenvironment and homeostasis to improving outcomes.

Assessment of the interaction effect between injury regions in multiple injuries: A nationwide cohort study in Japan

BACKGROUND

There have been no clinical studies to sufficiently reveal the interaction effect generated by combinations of injury regions of multiple injuries. We hypothesized that certain combinations of trauma regions might lead to increased risk of traumatic death and aimed to verify this hypothesis using a nationwide trauma registry in Japan.

MATERIALS AND METHODS

This was a retrospective study of trauma patients registered in the Japan Trauma Data Bank between 2004 and 2017. We included patients who suffered blunt trauma with an Injury Severity Score of 16 or more. The trauma was classified into four regions (head, chest, abdomen, and extremities), and a multivariable logistic regression analysis was performed that included interaction terms derived from the combination of two regions as covariates.

RESULTS

We included 78,280 trauma patients in this study. Among them, 16,100 (20.6%) patients were discharged to death. Multivariable logistic regression showed the odds ratio (OR) of in-hospital death compared with patients without injury of an Abbreviated Injury Scale score of 3 or more in each injured region as follows: head score, 2.31 (95% confidence interval [CI], 2.13-2.51); chest score, 2.28 (95% CI, 2.17-2.39); abdomen score, 1.68 (95% CI, 1.56-1.82); and extremities score, 1.84 (95% CI, 1.76-1.93), respectively. In addition, the ORs of the statistically significant interaction terms were as follows: head-chest 1.29 (95% CI, 1.13-1.48), chest-abdomen 0.77 (95% CI, 0.67-0.88), chest-extremities 1.95 (95% CI, 1.77-2.14), and abdomen-extremities 0.70 (95% CI, 0.62-0.79), respectively.

CONCLUSION

In this population, among patients with multiple injuries, a combination of head-chest trauma and chest-extremities trauma was shown to increase the risk of traumatic death.

LEVEL OF EVIDENCE

Prognostic, Level III.

Fracture fixation strategy and specific muscle tissue availability of neutrophilic granulocytes following mono- and polytrauma: intramedullary nailing vs. external fixation of femoral fractures

Background

In the stabilization of femoral fractures in mono- and polytrauma, clinical practice has shown better care through intramedullary nailing. However, the reason why this is the case is not fully understood. In addition to concomitant injuries, the immunological aspect is increasingly coming to the fore. Neutrophil granulocytes (PMNL), in particular next to other immunological cell types, seem to be associated with the fracture healing processes. For this reason, the early phase after fracture (up to 72 h after trauma) near the fracture zone in muscle tissue was investigated in a pig model.

Material and methods

A mono- and polytrauma pig model (sole femur fracture or blunt thoracic trauma, hemorrhagic shock, liver laceration, and femur fracture) was used to demonstrate the immunological situation through muscle biopsies and their analysis by histology and qRT-PCR during a 72 h follow-up phase. Two stabilization methods were used (intramedullary nail vs. external fixator) and compared with a nontraumatized sham group.

Results

Monotrauma shows higher PMNL numbers in muscle tissue compared with polytrauma (15.52 ± 5.39 mono vs. 8.23 ± 3.36 poly; p = 0.013), regardless of the treatment strategy. In contrast, polytrauma shows a longer lasting invasion of PMNL (24 h vs. 72 h). At 24 h in the case of monotrauma, the fracture treated with external fixation shows more PMNL than the fracture treated with intramedullary nailing (p = 0.026). This difference cannot be determined in polytrauma probably caused by a generalized immune response. Both monotrauma and polytrauma show a delayed PMNL increase in the muscle tissue of the uninjured side. The use of intramedullary nailing in monotrauma resulted in a significant increase in IL-6 (2 h after trauma) and IL-8 (24 and 48 h after trauma) transcription.

Conclusion

The reduction of PMNL invasion into the nearby muscle tissue of a monotrauma femur fracture stabilized by intramedullary nailing supports the advantages found in everyday clinical practice and therefore underlines the usage of nailing. For the polytrauma situation, the fixation seems to play a minor role, possibly due to a generalized immune reaction.

Registry-Based Mortality Analysis Reveals a High Proportion of Patient Decrees and Presumed Limitation of Therapy in Severe Geriatric Trauma

BACKGROUND

The treatment of severely injured patients, especially in older age, is complex, and based on strict guidelines.

METHODS

We conducted a retrospective study by analyzing our internal registry for mortality risk factors in deceased trauma patients. All patients that were admitted to the trauma bay of our level-1-trauma center from 2014 to 2018, and that died during the in-hospital treatment, were included. The aim of this study was to carry out a quality assurance concerning the initial care of severely injured patients.

RESULTS

In the 5-year period, 135 trauma patients died. The median (IQR) age was 69 (38-83) years, 71% were male, and the median (IQR) Injury Severity Score (ISS) was 25 (17-34) points. Overall, 41% of the patients suffered from severe traumatic brain injuries (TBI) (AIS_head ≥ 4 points). For 12.7%, therapy was finally limited owing to an existing patient's decree; in 64.9% with an uncertain prognosis, a 'therapia minima' was established in consensus with the relatives.

CONCLUSION

Although the mortality rate was primarily related to the severity of the injury, a significant number of deaths were not exclusively due to medical reasons, but also to a self-determined limitation of therapy for severely injured geriatric patients. The conscientious documentation concerning the will of the patient is increasingly important in supporting medical decisions.

miR-142-3p Expression Is Predictive for Severe Traumatic Brain Injury (TBI) in Trauma Patients

BACKGROUND

Predictive biomarkers in biofluids are the most commonly used diagnostic method, but established markers in trauma diagnostics lack accuracy. This study investigates promising microRNAs (miRNA) released from affected tissue after severe trauma that have predictive values for the effects of the injury.

METHODS

A retrospective analysis of prospectively collected data and blood samples of n = 33 trauma patients (ISS ≥ 16) is provided. Levels of miR-9-5p, -124-3p, -142-3p, -219a-5p, -338-3p and -423-3p in severely injured patients (PT) without traumatic brain injury (TBI) or with severe TBI (PT + TBI) and patients with isolated TBI (isTBI) were measured within 6 h after trauma.

RESULTS

The highest miR-423-3p expression was detected in patients with severe isTBI, followed by patients with PT + TBI, and lowest levels were found in PT patients without TBI (2^-∆∆Ct, p = 0.009). A positive correlation between miR-423-3p level and increasing AIS_head (p = 0.001) and risk of mortality (RISC II, p = 0.062) in trauma patients (n = 33) was found. ROC analysis of miR-423-3p levels revealed them as statistically significant to predict the severity of brain injury in trauma patients (p = 0.006). miR-124-3p was only found in patients with severe TBI, miR-338-3p was shown in all trauma groups. miR-9-5p, miR-142-3p and miR-219a-5p could not be detected in any of the four groups.

CONCLUSION

miR-423-3p expression is significantly elevated after isolated traumatic brain injury and predictable for severe TBI in the first hours after trauma. miR-423-3p could represent a promising new biomarker to identify severe isolated TBI.

Altered cell surface receptor dynamics and circulatory occurrence of neutrophils in a small animal fracture model

INTRODUCTION

Excessive activation of the immune response after femoral fractures and fracture fixation is potentially associated with the development of systemic and local complications, particularly in multiple trauma patients. A dysregulated function of neutrophils, the most prevailing immune cells in circulation, has been discussed as a central pathophysiological background for these unfavourable post-traumatic courses. Our aim was to investigate alterations in activity and functionality as expressed by the cell surface receptor dynamics of circulatory neutrophils after femoral fracture and intramedullary stabilization.

MATERIAL AND METHODS

After intramedullary stabilization, an isolated femur fracture was induced in 18 Sprague-Dawley rats. Animals were terminated at different time points, i.e. after 3 (n = 5, group 3d), 7 (n = 5, group 7d) and 14 (n = 5, Group 14d) days and grouped accordingly. Additionally, baseline measurements were performed in one control animal per study group (n = 3) after anaesthesia induction and termination, without prior intramedullary nailing and fracture induction. The numbers and cell surface expression of CD11b, CD11a, CD62 L, and CD49d of circulating neutrophils were compared between groups.

RESULTS

Neutrophil numbers were significantly reduced at 3 days compared with baseline measurements (1.2 × 10⁵ vs. 6.3 × 10⁵ cells/mL, p < 0.01). By day 7, neutrophil counts significantly increased back to homeostatic levels (p < 0.05). At day 3, CD11b-expression was significantly reduced, whereas CD11a-expression was increased compared with the baseline measurements (p < 0.05). At day 7, the circulatory neutrophil pool exhibited a unique CD11b^high/CD11a^high-neutrophil subset showing a significantly increased co-expression of CD49d. The expression of CD62 L did not change significantly throughout the experiment compared with baseline measurements.

CONCLUSIONS

This descriptive small animal fracture study is the first to show that an intramedullary stabilized femur fracture is associated with a temporary reduction in circulatory neutrophil count and concurrent changes in circulatory neutrophil function. Moreover, we demonstrated that the restoration to homeostatic neutrophil activation status occurs concomitantly with the appearance of a novel neutrophil subtype (CD11b^high/CD11a^high) in circulation. Our fundamental new findings of the changes in circulatory neutrophil count and functionality after trauma form an excellent basis for future studies to further elucidate the role of neutrophils as activators and regulators of different post-traumatic processes, potentially resulting in local (e.g., fracture healing disturbances) or systemic (e.g., MODS) complications. This might result in the development of specific therapies to reduce adverse outcomes after trauma.

Severe Traumatic Brain Injury (TBI) Modulates the Kinetic Profile of the Inflammatory Response of Markers for Neuronal Damage

The inflammatory response plays an important role in the pathophysiology of multiple injuries. This study examines the effects of severe trauma and inflammatory response on markers of neuronal damage. A retrospective analysis of prospectively collected data in 445 trauma patients (Injury Severity Score (ISS) ≥ 16) is provided. Levels of neuronal biomarkers (calcium-binding Protein B (S100b), Enolase2 (NSE), glial fibrillary acidic protein (GFAP)) and Interleukins (IL-6, IL-10) in severely injured patients (with polytrauma (PT)) without traumatic brain injury (TBI) or with severe TBI (PT+TBI) and patients with isolated TBI (isTBI) were measured upon arrival until day 5. S100b, NSE, GFAP levels showed a time-dependent decrease in all cohorts. Their expression was higher after multiple injuries (p = 0.038) comparing isTBI. Positive correlation of marker level after concomitant TBI and isTBI (p = 0.001) was noted, while marker expression after PT appears to be independent. Highest levels of IL-6 and -10 were associated to PT und lowest to isTBI (p < 0.001). In all groups pro-inflammatory response (IL-6/-10 ratio) peaked on day 2 and at a lower level on day 4. Severe TBI modulates kinetic profile of inflammatory response by reducing interleukin expression following trauma. Potential markers for neuronal damage have a limited diagnostic value after severe trauma because undifferentiated increase.

The impact of intramedullary nailing on the characteristics of the pulmonary neutrophil pool in rodents

PURPOSE

Dysregulation of polymorphonuclear neutrophil (PMN) biology is associated with the development of inflammatory complications after trauma, such as acute respiratory distress syndrome (ARDS). It has been demonstrated that intramedullary nailing is both associated with altered pulmonary neutrophil deposition and the occurrence of ARDS. This standardized study aimed to characterize the long-term remote neutrophil response in the lungs in case of a femur fracture and intramedullary nailing.

METHODS

A standardized rat model including intramedullary nailing and a femur fracture was utilized. Groups were terminated after observation times of three, seven and 14 days. Neutrophils were isolated from lung parenchyma and broncho-alveolar lavage fluid (BALF) and analyzed by flow cytometry. Absolute neutrophil numbers as well as membrane expression levels of CD11b, CD62L, and CD11a were compared.

RESULTS

Pulmonary neutrophil numbers were increased 3 days after intervention. Membrane expression levels of CD11b (P < 0.01), CD62L (P < 0.01), and CD11a (P = 0.06) on parenchymal PMNs increased as well after 3 days. Thereafter, values restored gradually to physiological levels. Furthermore, neutrophil activation status patterns between parenchymal and BALF neutrophil pools did not correlate.

CONCLUSIONS

The current study demonstrates that IMN and a femur fracture are associated with transient increased pulmonary PMN deposition, as well as a specific pattern of activation characterized by temporary increased selectin and integrin receptor expression on pulmonary neutrophils. This phenomenon might play an important role in the pathomechanism of ARDS after IMN. Moreover, we found striking differences between parenchymal and BALF-neutrophil populations, demonstrating the limited readout potential of BALF analysis to investigate the entire pulmonary neutrophil pool.

Endogenous Uteroglobin as Intrinsic Anti-inflammatory Signal Modulates Monocyte and Macrophage Subsets Distribution Upon Sepsis Induced Lung Injury

Sepsis is a serious clinical condition which can cause life-threatening organ dysfunction, and has limited therapeutic options. The paradigm of limiting excessive inflammation and promoting anti-inflammatory responses is a simplified concept. Yet, the absence of intrinsic anti-inflammatory signaling at the early stage of an infection can lead to an exaggerated activation of immune cells, including monocytes and macrophages. There is emerging evidence that endogenous molecules control those mechanisms. Here we aimed to identify and describe the dynamic changes in monocyte and macrophage subsets and lung damage in CL57BL/6N mice undergoing blunt chest trauma with subsequent cecal ligation and puncture. We showed that early an increase in systemic and activated Ly6C⁺CD11b⁺CD45⁺Ly6G^- monocytes was paralleled by their increased emigration into lungs. The ratio of pro-inflammatory Ly6C^highCD11b⁺CD45⁺Ly6G^- to patrolling Ly6C^lowCD11b⁺CD45⁺Ly6G^- monocytes significantly increased in blood, lungs and bronchoalveolar lavage fluid (BALF) suggesting an early transition to inflammatory phenotypes during early sepsis development. Similar to monocytes, the level of pro-inflammatory Ly6C^highCD45⁺F4/80⁺ macrophages increased in lungs and BALF, while tissue repairing Ly6C^lowCD45⁺F4/80⁺ macrophages declined in BALF. Levels of inflammatory mediators TNF-α and MCP-1 in blood and RAGE in lungs and BALF were elevated, and besides their boosting of inflammation via the recruitment of cells, they may promote monocyte and macrophage polarization, respectively, toward the pro-inflammatory phenotype. Neutralization of uteroglobin increased pro-inflammatory cytokine levels, activation of inflammatory phenotypes and their recruitment to lungs; concurrent with increased pulmonary damage in septic mice. In in vitro experiments, the influence of uteroglobin on monocyte functions including migratory behavior, TGF-β1 expression, cytotoxicity and viability were proven. These results highlight an important role of endogenous uteroglobin as intrinsic anti-inflammatory signal upon sepsis-induced early lung injury, which modules the early monocyte/macrophages driven inflammation.

Short Summary

Blunt chest injury is the third largest cause of death following major trauma, and ongoing excessive pro-inflammatory immune response entails high risk for the development of secondary complications, such as sepsis, with limited therapeutic options. In murine double hit trauma consisting of thoracic trauma and subsequent cecal ligation and puncture, we investigated the cytokine profile, pulmonary epithelial integrity and phenotypic shift of patrolling Ly6C^lowCD11b⁺CD45⁺Ly6G^- monocytes and Ly6C^lowCD45⁺F4/80⁺ macrophages to pro-inflammatory Ly6C^highCD11b⁺CD45⁺Ly6G^- monocytes and Ly6C^highCD45⁺F4/80⁺ cells in blood, lungs and bronchoalveolar lavage fluid (BALF). Pro-inflammatory mediators and phenotypes were elevated and uteroglobin neutralization led to further increase. Enhanced total protein levels in BALF suggests leakage of respiratory epithelium. In vitro, uteroglobin inhibited the migratory capacity of monocytes and the TGF-β1 expression without affecting the viability. These results highlight an important role of endogenous uteroglobin as an intrinsic anti-inflammatory signal upon sepsis-induced early lung injury, which modulates the early monocyte/macrophages driven inflammation.

Early Local Inhibition of Club Cell Protein 16 Following Chest Trauma Reduces Late Sepsis-Induced Acute Lung Injury

Blunt thoracic trauma (TxT) deteriorates clinical post-injury outcomes. Ongoing inflammatory changes promote the development of post-traumatic complications, frequently causing Acute Lung Injury (ALI). Club Cell Protein (CC)16, a pulmonary anti-inflammatory protein, correlates with lung damage following TxT. Whether CC16-neutralization influences the inflammatory course during ALI is elusive. Ninety-six male CL57BL/6N mice underwent a double hit model of TxT and cecal ligation puncture (CLP, 24 h post-TxT). Shams underwent surgical procedures. CC16 was neutralized by the intratracheal application of an anti-CC16-antibody, either after TxT (early) or following CLP (late). Euthanasia was performed at 6 or 24 h post-CLP. Systemic and pulmonary levels of IL-6, IL-1β, and CXCL5 were determined, the neutrophils were quantified in the bronchoalveolar lavage fluid, and histomorphological lung damage was assessed. ALI induced a significant systemic IL-6 increase among all groups, while the local inflammatory response was most prominent after 24 h in the double-hit groups as compared to the shams. Significantly increased neutrophilic infiltration upon double hit was paralleled with the enhanced lung damage in all groups as compared to the sham, after 6 and 24 h. Neutralization of CC16 did not change the systemic inflammation. However, early CC16-neutralization increased the neutrophilic infiltration and lung injury at 6 h post-CLP, while 24 h later, the lung injury was reduced. Late CC16-neutralization increased neutrophilic infiltration, 24 h post-CLP, and was concurrent with an enhanced lung injury. The data confirmed the anti-inflammatory potential of endogenous CC16 in the murine double-hit model of ALI.