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

AIM: Severely injured patients experience substantial immunological stress upon traumatic insult. Next to the direct local tissue injury also other organs, which are not directly injured such as liver and lung, are frequently affected by a so-called remote organ damage (ROD) after trauma. Thus, we studied the inflammatory response of lung and liver either after isolated femur fracture as example for ROD, or after multiple trauma in a porcine polytrauma model. METHODS: Twenty-four male pigs (Sus scrofa) underwent either isolated standardized femoral fracture (monotrauma, MT, n = 12) or polytrauma (PT, n = 12). PT consisted of a femur fracture, lung contusion, liver laceration, hemorrhagic shock, subsequent resuscitation and surgical fracture fixation. Six animals served as controls (sham). After 72 h inflammatory changes were determined by analyses of the interleukin (IL)-6 gene expression and tissue infiltration of polymorphonuclear leukocyte (PMN, myeloperoxidase staining). ROD in MT, and lung as well as liver damage in PT were assessed histologically by hematoxylin-eosin staining. Expression of phosphorylated p65 NF-κB was evaluated by immunohistology. RESULTS: IL-6 increased in lungs and liver in both groups MT and PT, respectively, compared to sham. Similarly, PMN infiltration of the lungs and liver increased significantly after both MT and PT compared to sham. Histological evaluation demonstrated tissue damage notably in lungs after MT, while tissue damage after PT was found in both lung and liver after PT. p65 NF-κB tended to an increase upon MT, and was significantly enhanced after PT in both tissues. CONCLUSION: Our data indicate that remote organ damage after MT notably in lungs was associated with an enhanced inflammatory response. Severe polytrauma substantially intensifies this response and organ damage in the underlying model.

Leukotriene B4 indicates lung injury and on-going inflammatory changes after severe trauma in a porcine long-term model.

BACKGROUND: Recognizing patients at risk for pulmonary complications (PC) is of high clinical relevance. Migration of polymorphonuclear leukocytes (PMN) to inflammatory sites plays an important role in PC, and is tightly regulated by specific chemokines including interleukin (IL)-8 and other mediators such as leukotriene (LT)B4. Previously, we have reported that LTB4 indicated early patients at risk for PC after trauma. Here, the relevance of LTB4 to indicating lung integrity in a newly established long-term porcine severe trauma model (polytrauma, PT) was explored. METHODS: Twelve pigs (3 months old, 30 ± 5kg) underwent PT including standardized femur fracture, lung contusion, liver laceration, hemorrhagic shock, subsequent resuscitation and surgical fracture fixation. Six animals served as controls (sham). After 72h lung damage and inflammatory changes were assessed. LTB4 was determined in plasma before the experiment, immediately after trauma, and after 2, 4, 24 or 72h. Bronchoalveolar lavage (BAL)-fluid was collected prior and after the experiment. RESULTS: Lung injury, local gene expression of IL-8, IL-1ß, IL-10, IL-18 and PMN-infiltration into lungs increased significantly in PT compared with sham. Systemic LTB4 increased markedly in both groups 4h after trauma. Compared with declined plasma LTB4 levels in sham, LTB4 increased further in PT after 72h. Similar increase was observed in BAL-fluid after PT. CONCLUSIONS: In a severe trauma model, sustained changes in terms of lung injury and inflammation are determined at day 3 post-trauma. Specifically, increased LTB4 in this porcine long-term model indicated a rapid inflammatory alteration both locally and systemically. The results support the concept of LTB4 as a biomarker for PC after severe trauma and lung contusion.

Early decreased TLR2 expression on monocytes is associated with their reduced phagocytic activity and impaired maturation in a porcine polytrauma model.

In their post-traumatic course, trauma patients suffering from multiple injuries have a high risk for immune dysregulation, which may contribute to post-injury complications and late mortality. Monocytes as specific effector cells of the innate immunity play a crucial role in inflammation. Using their Pattern Recognition Receptors (PRRs), notably Toll-Like Receptors (TLR), the monocytes recognize pathogens and/or pathogen-associated molecular patterns (PAMPs) and organize their clearance. TLR2 is the major receptor for particles of gram-positive bacteria, and initiates their phagocytosis. Here, we investigated the phagocytizing capability of monocytes in a long-term porcine severe trauma model (polytrauma, PT) with regard to their TLR2 expression. Polytrauma consisted of femur fracture, unilateral lung contusion, liver laceration, hemorrhagic shock with subsequent resuscitation and surgical fracture fixation. After induction of PT, peripheral blood was withdrawn before (-1 h) and directly after trauma (0 h), as well as 3.5 h, 5.5 h, 24 h and 72 h later. CD14+ monocytes were identified and the expression levels of H(S)LA-DR and TLR2 were investigated by flow cytometry. Additionally, the phagocytizing activity of monocytes by applying S. aureus particles labelled with pHrodo fluorescent reagent was also assessed by flow cytometry. Furthermore, blood samples from 10 healthy pigs were exposed to a TLR2-neutralizing antibody and subsequently to S. aureus particles. Using flow cytometry, phagocytizing activity was determined. P below 0.05 was considered significant. The number of CD14+ monocytes of all circulating leukocytes remained constant during the observational time period, while the percentage of CD14+H(S)LA-DR+ monocytes significantly decreased directly, 3.5 h and 5.5 h after trauma. The percentage of TLR2+ expressing cells out of all monocytes significantly decreased directly, 3.5 h and 5.5 h after trauma. The percentage of phagocytizing monocytes decreased immediately and remained lower during the first 3.5 h after trauma, but increased after 24 h. Antagonizing TLR2 significantly decreased the phagocytizing activity of monocytes. Both, decreased percentage of activated as well as TLR2 expressing monocytes persisted as long as the reduced phagocytosis was observed. Moreover, neutralizing TLR2 led to a reduced capability of phagocytosis as well. Therefore, we assume that reduced TLR2 expression may be responsible for the decreased phagocytizing capacity of circulating monocytes in the early post-traumatic phase.

Alcohol Intoxication Reduces Systemic Interleukin-6 Levels and Leukocyte Counts After Severe TBI Compared With Not Intoxicated TBI Patients.

BACKGROUND: The effect of alcohol consumption on inflammatory state and outcome in brain-injured patients remains controversial. We analyzed the influence of positive blood alcohol concentration (BAC) on inflammatory changes, inhospital complications, and mortality in traumatic brain injury (TBI) patients. PATIENTS AND METHODS: Patients with an Injury Severity Score (ISS) at least 16 and Abbreviated Injury Scale of head (AIS-head) at least 3 were included upon arrival in the emergency room and grouped according to positive BAC (>0.5‰, BAC) vs. less than 0.5‰ alcohol (no BAC). Injury severity, vital signs, complications, mortality, and systemic interleukin (IL)-6 levels were prospectively determined, and BAC was quantified. According to ISS, AIS-head, age, and sex, we performed matched-pair analysis. RESULTS: A total of 101 TBI patients were included. Of them 74 patients were dedicated to no BAC group and 27 to BAC group. ISS was significantly higher in the no BAC group. Positive BAC group required significantly less packed red blood cells and fresh frozen plasma (P < 0.05). Shorter ICU stays were found in BAC-positive patients. Inhospital complications, including single/multiple organ failure, systemic inflammatory response syndrome, sepsis, pneumonia, and acute respiratory distress syndrome, showed no significant differences. Systemic IL-6 levels and leukocyte counts (IL-6: 65.0 ±â€Š8.0 vs. 151.8 ±â€Š22.3; leukocytes: 10.2 ±â€Š0.9 vs. 13.2 ±â€Š0.8, both P < 0.05) were significantly lower in BAC-positive patients. Matched-pair analysis was performed with 27 pairs. No significant differences in transfusions were monitored after matching. However, lowered systemic IL-6 levels and leukocyte counts in the BAC group were also detected after matching, indicating that this effect is ISS-independent. CONCLUSIONS: This study shows that positive BAC in TBI patients is associated with lower systemic IL-6 levels and leukocyte numbers, indicating that positive BAC may have immunosuppressive effects in this cohort of patients compared with TBI patients who were not alcohol intoxicated.

Influence of gender on systemic IL-6 levels, complication rates and outcome after major trauma.

BACKGROUND: While female gender was associated with lower rates of systemic inflammatory response syndrome (SIRS), sepsis and single and/or multiple organ failure (MOF), contradictory data suggest no correlation between gender and complication rates and/or outcome in trauma patients (TP). Here, we analyzed the gender influence on systemic interleukin (IL)-6 levels and outcome in TP. PATIENTS/METHODS: 343 TP with injury severity scores (ISS) ≥16 were included upon admittance to the emergency department (ED) and grouped to male (n=257) vs. female (n=86). Injury severity, vital signs, physiological parameters, length of intensive care unit (ICU) and in-hospital stay, outcome parameters including SIRS, sepsis, respiratory complications, single- and/or MOF and in-hospital mortality were analyzed. Systemic IL-6 levels during the first 10 post-injury days were determined daily. RESULTS: Age (45.0±1.0 vs. 48.2±2.1) and ISS (27.1±0.8 vs. 24.7±1.2) were comparable between both groups. Abbreviated Injury Scale (AIS) ≥3 of chest and abdominal body regions were significantly higher in male TP (chest:51.02% vs. 36.05%, abdomen:19.84% vs. 10.47%, p<0.05). IL-6 was significantly increased in male TP on post-injury days 1 and 2 (d1:363.9±72.58 vs. 163.7±25.98; d2:194.3±31.38 vs. 114.3±17.81pg/ml, p<0.05). Multivariate analysis excluded an association of increased chest or abdominal injury occurrence with IL-6 levels. Female vs. male TP had significantly lower SIRS and sepsis occurrence (SIRS:40.70% vs. 53.31%, sepsis:6.98% vs. 19.46%, p<0.05). There were no gender-based differences regarding ICU or in-hospital stay, single and/or MOF and respiratory complications. CONCLUSIONS: Taken together, higher systemic IL-6 levels after trauma are associated with enhanced susceptibility for SIRS and sepsis in male patients.

I-FABP and L-FABP are early markers for abdominal injury with limited prognostic value for secondary organ failures in the post-traumatic course.

BACKGROUND: Trauma patients sustaining abdominal trauma exhibit high risk of organ failure and/or sepsis aggravating morbidity and mortality during the post-traumatic course. The present study re-evaluates L- and I-FABPs (small fatty acid binding proteins) as early biomarkers for abdominal injury (AI) in a large cohort of patients and analyzes their potential as indicators of specific organ failure and their association with sepsis and/or mortality in the post-traumatic course. METHODS: This prospective study included 134 multiply traumatized patients (ISS≥16). Fifty-nine had AI (abbreviated AI Scale, AISAbd≥3) and 75 had no AI (noAI). Twenty healthy volunteers served as controls. Plasma I- and L-FABP levels were measured at the admittance to the emergency room (d0) and up to 10 days daily (d1-d10) using ELISA. Sepsis, organ failure, multiple organ failure (MOF) and mortality were assessed. RESULTS: Median L- and I-FABP in the AI-group [258 (IQR=71-500) ng/mL and 328 (IQR=148-640) pg/mL, respectively] were higher compared to noAI-group [30 (IQR=18-50) ng/mL and 60 (IQR=40-202) pg/mL, p>0.05] on d0. Sensitivity and specificity to detect AI were 80% and 75% for L-FABP, 78% and 62% for I-FABP. Both FABPs decline with the post-traumatic course to control levels. On d0 and d1, FABPs correlate with the Sepsis-related Organ Failure Assessment (SOFA) score of the following day (d0: ρ:0.33, ρ:0.46, d1: ρ:0.48, ρ:0.35). No other correlations were found. Eight percent of all patients developed sepsis, 18% pneumonia, 4% urinary tract infection, 3% acute kidney failure and one MOF. FABPs correlated neither with Simplifed Acute Physiology Score (SAPS)-II nor to sepsis. All patients with acute kidney failure demonstrated enhanced L-FAPB levels before the increase of serum creatinine levels. CONCLUSIONS: Our results confirm the potential of L- and I-FABP to indicate abdominal injuries initially after trauma. Except L-FABP as indicator of acute kidney failure both FABPs have to be further evaluated as predictors for other organ failures, sepsis and/or mortality.

Circulating leukotriene B4 identifies respiratory complications after trauma.

BACKGROUND: Leukotriene B4 (LTB4), a proinflammatory lipid mediator correlates well with the acute phase of Acute Respiratory Distress Syndrome (ARDS). Therefore, LTB4-levels were investigated to determine whether they might be a useful clinical marker in predicting pulmonary complications (PC) in multiply traumatized patients. METHODS: Plasma levels of LTB4 were determined in 100 patients on admission (ED) and for five consecutive days (daily). Twenty healthy volunteers served as control. LTB4-levels were measured by ELISA. Thirty patients developed PC (pneumonia, respiratory failure, acute lung injury (ALI), ARDS, pulmonary embolism) and 70 had no PC (ØPC). RESULTS: LTB4-levels in the PC-group [127.8 pg/mL, IQR: 104-200pg/ml] were significantly higher compared to the ØPC-group on admission [95.6 pg/mL, IQR: 55-143 pg/mL] or control-group [58.4 pg/mL, IQR: 36-108 pg/mL]. LTB4 continuously declined to basal levels from day 1 to 5 without differences between the groups. The cutoff to predict PC was calculated at 109.6 pg/mL (72% specificity, 67% sensitivity). LTB4 was not influenced by overall or chest injury severity, age, gender or massive transfusion. Patients with PC received mechanical ventilation for a significantly longer period of time, and had prolonged intensive care unit and overall hospital stay. CONCLUSION: High LTB4-levels indicate risk for PC development in multiply traumatized patients.