Different experimental multiple trauma models induce comparable inflammation and organ injury

Effects of remote ischemic preconditioning on early markers of intestinal injury in experimental hemorrhage in rats

The maintenance of intestinal integrity and barrier function under conditions of restricted oxygen availability is crucial to avoid bacterial translocation and local inflammation. Both lead to secondary diseases after hemorrhagic shock and might increase morbidity and mortality after surviving the initial event. Monitoring of the intestinal integrity especially in the early course of critical illness remains challenging. Since microcirculation and mitochondrial respiration are main components of the terminal stretch of tissue oxygenation, the evaluation of microcirculatory and mitochondrial variables could identify tissues at risk during hypoxic challenges, indicate an increase of intestinal injury, and improve our understanding of regional pathophysiology during acute hemorrhage. Furthermore, improving intestinal microcirculation or mitochondrial respiration, e.g. by remote ischemic preconditioning (RIPC) that was reported to exert a sufficient tissue protection in various tissues and was linked to mediators with vasoactive properties could maintain intestinal integrity. In this study, postcapillary oxygen saturation (µHbO2), microvascular flow index (MFI) and plasmatic D-lactate concentration revealed to be early markers of intestinal injury in a rodent model of experimental hemorrhagic shock. Mitochondrial function was not impaired in this experimental model of acute hemorrhage. Remote ischemic preconditioning (RIPC) failed to improve intestinal microcirculation and intestinal damage during hemorrhagic shock.

Effect of access to the integrated treatment model for patients with multiple severe injuries in the Chinese population

AIMS

The aim of this study was to enhance the effectiveness of an integrated treatment model for patients with severe multiple injuries in China.

METHODS

In this study, we conducted a retrospective analysis of data from 110 patients with multiple severe injuries. These patients were divided into two groups based on the treatment model they received. The first group, called the MDTM group, received the integrated treatment model, which involved a multidisciplinary team-based approach. The second group, designated the TSM group, received the traditional specialist-based treatment model. The primary outcome measure was the survival rate of patients after treatment. Secondary outcomes included the time spent on hospital emergency treatment, the length of hospital stay, the mortality rate, and family satisfaction.

RESULTS

The survival rate of patients after treatment in the MDTM group (83.93%) was significantly greater than that in the TSM group (70.37%). Consequently, the mortality of patients after treatment in the MDTM group (16.07%) was significantly lower than that in the TSM group (29.63%). Furthermore, the MDTM group demonstrated significantly shorter durations of rescue efforts and shorter hospital stays. Additionally, family satisfaction was significantly greater in the MDTM group.

CONCLUSION

The integrated treatment model shows potential for optimizing outcomes for patients with multiple severe injuries and generating higher levels of family satisfaction. This model holds practical applicability in the context of China and may help alleviate the strained relationship between physicians and patients.

Age-related exacerbation of lung damage after trauma is associated with increased expression of inflammasome components

Background

Trauma, a significant global cause of mortality and disability, often leads to fractures and hemorrhagic shock, initiating an exaggerated inflammatory response, which harms distant organs, particularly the lungs. Elderly individuals are more vulnerable to immune dysregulation post-trauma, leading to heightened organ damage, infections, and poor health outcomes. This study investigates the role of NF-κB and inflammasomes in lung damage among aged mice post-trauma.

Methods

Twelve male C57BL/6J mice underwent hemorrhagic shock and a femoral fracture (osteotomy) with external fixation (Fx) (trauma/hemorrhage, THFx), while another 12 underwent sham procedures. Mice from young (17-26 weeks) and aged (64-72 weeks) groups (n=6) were included. After 24h, lung injury was assessed by hematoxylin-eosin staining, prosurfactant protein C (SPC) levels, HMGB1, and Muc5ac qRT-PCR. Gene expression of Nlrp3 and Il-1β, and protein levels of IL-6 and IL-1β in lung tissue and bronchoalveolar lavage fluid were determined. Levels of lung-infiltrating polymorphonuclear leukocytes (PMNL) and activated caspase-3 expression to assess apoptosis, as well as NLRP3, ASC, and Gasdermin D (GSDMD) to assess the expression of inflammasome components were analyzed via immunostaining. To investigate the role of NF-κB signaling, protein expression of phosphorylated and non-phosphorylated p50 were determined by western blot.

Results

Muc5ac, and SPC as lung protective proteins, significantly declined in THFx versus sham. THFx-aged exhibited significantly lower SPC and higher HMGB1 levels versus THFx-young. THFx significantly increased activated caspase-3 versus both sham groups, and THFx-aged had significantly more caspase-3 positive cells versus THFx-young. IL-6 significantly increased in both sham and THFx-aged groups versus corresponding young groups. THFx significantly enhanced PMNL in both groups versus corresponding sham groups. This increase was further heightened in THFx-aged versus THFx-young. Expression of p50 and phosphorylated p50 increased in all aged groups, and THFx-induced p50 phosphorylation significantly increased in THFx-aged versus THFx-young. THFx increased the expression of inflammasome markers IL-1β, NLRP3, ASC and GSDMD versus sham, and aging further amplified these changes significantly.

Conclusion

This study's findings suggest that the aging process exacerbates the excessive inflammatory response and damage to the lung following trauma. The underlying mechanisms are associated with enhanced activation of NF-κB and increased expression of inflammasome components.

Temporal and Spatial Patterns of Inflammation and Tissue Injury in Patients with Postoperative Respiratory Failure after Lung Resection Surgery: A Nested Case-Control Study

Thoracic surgeries involving resection of lung tissue pose a risk of severe postoperative pulmonary complications, including acute respiratory distress syndrome (ARDS) and respiratory failure. Lung resections require one-lung ventilation (OLV) and, thus, are at higher risk of ventilator-induced lung injury (VILI) attributable to barotrauma and volutrauma in the one ventilated lung, as well as hypoxemia and reperfusion injury on the operated lung. Further, we also aimed to assess the differences in localized and systemic markers of tissue injury/inflammation in those who developed respiratory failure after lung surgery versus matched controls who did not develop respiratory failure. We aimed to assess the different inflammatory/injury marker patterns induced in the operated and ventilated lung and how this compared to the systemic circulating inflammatory/injury marker pattern. A case-control study nested within a prospective cohort study was performed. Patients with postoperative respiratory failure after lung surgery (n = 5) were matched with control patients (n = 6) who did not develop postoperative respiratory failure. Biospecimens (arterial plasma, bronchoalveolar lavage separately from ventilated and operated lungs) were obtained from patients undergoing lung surgery at two timepoints: (1) just prior to initiation of OLV and (2) after lung resection was completed and OLV stopped. Multiplex electrochemiluminescent immunoassays were performed for these biospecimen. We quantified 50 protein biomarkers of inflammation and tissue injury and identified significant differences between those who did and did not develop postoperative respiratory failure. The three biospecimen types also display unique biomarker patterns.

Acute Intoxication With Alcohol Reduces Trauma-Induced Proinflammatory Response and Barrier Breakdown in the Lung via the Wnt/β-Catenin Signaling Pathway

Background

Trauma is the third leading cause of mortality worldwide. Upon admission, up to 50% of traumatized patients are acutely intoxicated with alcohol, which might lead to aberrant immune responses. An excessive and uncontrolled inflammatory response to injury is associated with damage to trauma-distant organs. We hypothesize that, along with inflammation-induced apoptosis, the activation of the Wnt/β-catenin signaling pathway would cause breakdown of the lung barrier and the development of lung injury after trauma. It remains unclear whether ethanol intoxication (EI) prior to trauma and hemorrhagic shock will attenuate inflammation and organ injury.

Methods

In this study, 14 male C57BL/6J mice were randomly assigned to two groups and exposed either to EtOH or to NaCl as a control by an oral gavage before receiving a femur fracture (Fx) and hemorrhagic shock, followed by resuscitation (THFx). Fourteen sham animals received either EtOH or NaCl and underwent surgical procedures without THFx induction. After 24 h, oil red O staining of fatty vacuoles in the liver was performed. Histological lung injury score (LIS) was assessed to analyze the trauma-induced RLI. Gene expression of Cxcl1, Il-1β, Muc5ac, Tnf, and Tnfrsf10b as well as CXCL1, IL-1β, and TNF protein levels in the lung tissue and bronchoalveolar lavage fluid were determined by RT-qPCR, ELISA, and immunohistological analyses. Infiltrating polymorphonuclear leukocytes (PMNLs) were examined via immunostaining. Apoptosis was detected by activated caspase-3 expression in the lung tissue. To confirm active Wnt signaling after trauma, gene expression of Wnt3a and its inhibitor sclerostin (Sost) was determined. Protein expression of A20 and RIPK4 as possible modulators of the Wnt signaling pathway was analyzed via immunofluorescence.

Results

Significant fatty changes in the liver confirmed the acute EI. Histopathology and decreased Muc5ac expression revealed an increased lung barrier breakdown and concomitant lung injury after THFx versus sham. EI prior trauma decreased lung injury. THFx increased not only the gene expression of pro-inflammatory markers but also the pulmonary infiltration with PMNL and apoptosis versus sham, while EI prior to THFx reduced those changes significantly. EI increased the THFx-reduced gene expression of Sost and reduced the THFx-induced expression of Wnt3a. While A20, RIPK4, and membranous β-catenin were significantly reduced after trauma, they were enhanced upon EI.

Conclusion

These findings suggest that acute EI alleviates the uncontrolled inflammatory response and lung barrier breakdown after trauma by suppressing the Wnt/β-catenin signaling pathway.

Recent Developments in Mouse Trauma Research Models: A Mini-Review

The urgency to investigate trauma in a controlled and reproducible environment rises since multiple trauma still account for the most deaths for people under the age of 45. The most common multiple trauma include head as well as blunt thorax trauma along with fractures. However, these trauma remain difficult to treat, partially because the molecular mechanisms that trigger the immediate immune response are not fully elucidated. To illuminate these mechanisms, investigators have used animal models, primarily mice as research subjects. This mini review aims to 1) emphasize the importance of the development of clinically relevant murine trauma research, 2) highlight and discuss the existing conflict between simulating clinically relevant situations and elucidating molecular mechanisms, 3) describe the advantages and disadvantages of established mouse trauma models developed to simulate clinically relevant situations, 4) summarize and list established mouse models in the field of trauma research developed to simulate clinically relevant situations.

New Time-Related Insights into an Old Laboratory Parameter: Early CRP Discovered by IBM Watson Trauma Pathway Explorer© as a Predictor for Sepsis in Polytrauma Patients

The University Hospital Zurich together with IBM^® invented an outcome prediction tool based on the IBM Watson technology, the Watson Trauma Pathway Explorer^®. This tool is an artificial intelligence to predict three outcome scenarios in polytrauma patients: the Systemic Inflammatory Response Syndrome (SIRS) and sepsis within 21 days as well as death within 72 h. The knowledge of a patient’s future under standardized trauma treatment might be of utmost importance. Here, new time-related insights on the C-reactive protein (CRP) and sepsis are presented. Meanwhile, the validated IBM Watson Trauma Pathway Explorer^® offers a time-related insight into the most frequent laboratory parameters. In total, 3653 patients were included in the databank used by the application, and ongoing admissions are constantly implemented. The patients were grouped according to sepsis, and the CRP was analyzed according to the point of time at which the value was acquired (1, 2, 3, 4, 6, 8, 12, 24, and 48 h and 3, 4, 5, 7, 10, 14, and 21 days). The differences were analyzed using the Mann–Whitney U-Test; binary logistic regression was used to determine the dependency of prediction, and the Closest Top-left Threshold Method presented time-specific thresholds at which CRP is predictive for sepsis. The data were considered as significant at p < 0.05, all analyses were performed in R. The differences in the CRP value of the non-sepsis and sepsis groups are starting to be significant between 6 and 8 h (p < 0.05) after admission inclusive of post hoc analysis, and the binary logistic regression depicts a similar picture. The level of significance is reached between 6 and 8 h (p < 0.05) after admission. The knowledge of the outcome reflected by the CRP in polytrauma patients improves the surgeon’s tactical position to indicate operations to reduce antigenic load and avoid an infectious adverse outcome.

Resolution of inflammation in bone regeneration: From understandings to therapeutic applications

Impaired bone healing occurs in 5-10% of cases following injury, leading to a significant economic and clinical impact. While an inflammatory response upon injury is necessary to facilitate healing, its resolution is critical for bone tissue repair as elevated acute or chronic inflammation is associated with impaired healing in patients and animal models. This process is governed by important crosstalk between immune cells through mediators that contribute to resolution of inflammation in the local healing environment. Approaches modulating the initial inflammatory phase followed by its resolution leads to a pro-regenerative environment for bone regeneration. In this review, we discuss the role of inflammation in bone repair, the negative impact of dysregulated inflammation on bone tissue regeneration, and how timely resolution of inflammation is necessary to achieve normal healing. We will discuss applications of biomaterials to treat large bone defects with a specific focus on resolution of inflammation to modulate the immune environment following bone injury, and their observed functional benefits. We conclude the review by discussing future strategies that could lead to the realization of anti-inflammatory therapeutics for bone tissue repair.