Extracellular vesicles as mediators and markers of acute organ injury: current concepts.

Due to the continued high incidence and mortality rate worldwide, there is a need to develop new strategies for the quick, precise, and valuable recognition of presenting injury pattern in traumatized and poly-traumatized patients. Extracellular vesicles (EVs) have been shown to facilitate intercellular communication processes between cells in close proximity as well as distant cells in healthy and disease organisms. miRNAs and proteins transferred by EVs play biological roles in maintaining normal organ structure and function under physiological conditions. In pathological conditions, EVs change the miRNAs and protein cargo composition, mediating or suppressing the injury consequences. Therefore, incorporating EVs with their unique protein and miRNAs signature into the list of promising new biomarkers is a logical next step. In this review, we discuss the general characteristics and technical aspects of EVs isolation and characterization. We discuss results of recent in vitro, in vivo, and patients study describing the role of EVs in different inflammatory diseases and traumatic organ injuries. miRNAs and protein signature of EVs found in patients with acute organ injury are also debated.

The Influence of Alcohol on the Base Excess Parameter in Trauma Patients.

BACKGROUND: The base excess (BE) parameter can be used as an indicator of mortality. However, study results on the influence of alcohol on the validity of BE as a prognostic parameter in alcohol-intoxicated patients are controversial. Thus, this study examined the hypothesis: An increasing blood alcohol level reduces the prognostic value of the BE parameter on mortality. PATIENTS AND METHODS: In a retrospective analysis of the multicenter database of the TraumaRegister DGU, patients from 2015 to 2017 were grouped depending on their blood alcohol level (BAL) into a BAL+ and BAL- group. The hypothesis was verified using logistic regression with an assumed significance level of 1% (P < 0.01). RESULTS: Eleven thousand eight hundred eighty-nine patients were included; 9,472 patients in the BAL- group and 2,417 patients in the BAL+ group. Analysis of the BE showed lower values in the BAL+ group (BAL-: -1.8 ±â€Š4.4 mmol/L vs. BAL+: -3.4 ±â€Š4.6 mmol/L). There is a trend toward lower BE levels when BAL increases. Assuming a linear relationship, then BE decreases by 0.6 points per mille alcohol (95% CI: 0.5-0.7; P < 0.001). The mortality rate was significantly lower in the BAL+ group (BAL-: 11.1% vs. BAL+: 7.9%). The logistic regression analysis showed a significant beneficial influence of BAL+ on the mortality rate (OR 0.706, 95% CI 0.530-0.941, P = 0.018). To analyze whether a low BE (≤-6 mmol/L) has different prognostic effects in patients with and without alcohol, logistic regression models were calculated. However, the effect of BE ≤ -6 mmol/L was similar in both models (regression coefficients in BAL-/+ patients: 0.379/0.393). CONCLUSIONS: The data demonstrate an existing influence of alcohol on the BE parameter; however, this does not negatively affect the BE as a prognostic parameter at a threshold of ≤ -6 mmol/L.

Ethyl Pyruvate Reduces Systemic Leukocyte Activation via Caspase-1 and NF-κB After Blunt Chest Trauma and Haemorrhagic Shock.

Background: Blunt chest (thoracic) trauma (TxT) and haemorrhagic shock with subsequent resuscitation (H/R) induce strong systemic and local inflammatory response, which is closely associated with apoptotic cell loss and subsequently impaired organ function. The underlying mechanisms are not completely understood, therefore, the treatment of patients suffering from TxT+H/R is challenging. In our recent studies, we have demonstrated local anti-inflammatory effects of ethyl pyruvate (EtP) in lung and liver after TxT+H/R. Here, the therapeutic potential of a reperfusion regime with EtP on the early post-traumatic systemic inflammatory response and apoptotic changes after TxT followed by H/R were investigated. Methods: Female Lewis rats underwent TxT followed by haemorrhagic shock (60 min). Resuscitation was performed with own blood transfusion and either lactated Ringers solution (LR) or LR supplemented with EtP (50 mg/kg). Sham group underwent the surgical procedures. After 2 h blood as well as lung and liver tissues were obtained for analyses. Systemic activation of neutrophils (expression of CD11b and CD62L), leukocyte phagocytosis, apoptosis (caspase-3/7 activation), pyroptosis (caspase-1 activation) and NF-κB p65 activity were assessed. p < 0.05 was considered significant. Results: TxT+H/R-induced systemic activation of neutrophils (increased CD11b and reduced CD62L expression) was significantly reduced by EtP. Trauma-induced delayed neutrophil apoptosis was further reduced by EtP reperfusion but remained unaltered in monocytes. Reperfusion with EtP significantly increased the phagocytizing capacity of granulocytes. Trauma-induced inflammasome activation, which was observed in monocytes and not in neutrophils, was significantly reduced by EtP in both cell entities. NF-κB p65 activation, which was increased in neutrophils and monocytes was significantly decreased in monocytes. Conclusion: TxT+H/R-induced systemic activation of both neutrophils and monocytes concomitant with increased systemic inflammation was reduced by a reperfusion with EtP and was associated with a down-regulation of NF-κB p65 activation.

Alcohol­induced attenuation of post­traumatic inflammation is not necessarily liver­protective following trauma/hemorrhage.

Due to their high prevalence, blunt chest trauma (TxT) and hemorrhagic shock have a significant influence on the outcomes of trauma patients, causing severe modulations of the immune system and high mortality rates. Alcohol consumption in trauma patients has a high clinical impact. Studies investigating the timing of alcohol intoxication prior to trauma are limited, although there are two typical scenarios regarding alcohol consumption: Acute ('drink and drive scenario') and sub­acute ('evening binge drinking'). Therefore, the present study investigated the influence of either an acute or sub­acute alcohol­drinking scenario in an in vivo model of TxT and hemorrhagic shock, focusing on liver inflammation and outcomes. At 12 h (sub­acute) or 2 h (acute) before the experiment, female Lewis rats received a single oral dose of alcohol (ethanol, EtOH) or saline (NaCl, ctrl), followed by TxT, hemorrhagic shock (35±3 mm Hg) and resuscitation (H/R). The animals were either sacrificed 2 h later or their survival was determined for 72 h. The results revealed that EtOH induced significant fatty changes in the liver. TxT + H/R­induced increases in the gene expression of interleukin (IL)­6 and intercellular adhesion molecule­1 and the protein expression of tumor necrosis factor (TNF)­α and IL­1ß were significantly reduced in both EtOH groups compared with those in the corresponding TxT + H/R ctrl groups. The local presence of IL­10­expressing cells in the liver was significantly increased following TxT + H/R in all groups, although the sub­acute EtOH TxT + H/R group had a significantly higher proportion of IL­10­positive cells compared with all other groups. Stimulating peripheral whole blood with lipopolysaccharide led to significantly lower levels of TNF­α release in the sub­acute EtOH group compared with the levels in all other groups. Significant TxT + H/R­induced increases in liver transaminases and liver damage were most prominent in the sub­acute EtOH group. The TxT + H/R EtOH group exhibited the lowest levels of glucose. There were no significant differences in mortality rate among the TxT + H/R groups. The data obtained indicates that the severity of liver damage following TxT + H/R may depend on the timing of alcohol consumption and severity of trauma, but also on the balance between pro­ and anti­inflammatory responses.

Circulating Extracellular Vesicles and Their miR "Barcode" Differentiate Alcohol Drinkers With Liver Injury and Those Without Liver Injury in Severe Trauma Patients.

Short Summary: Extracellular vesicles (EVs), released during tissue/cell injury, contain a "barcode" indicating specific microRNAs (miRs) that can uncover their origin. We examined whether systemic EVs possessing hepatic miR-signatures would indicate ongoing liver injury and clinical complications in trauma patients (TP). We grouped the patients of alcoholic drinkers into "alcohol-drinkers with liver injury (LI)" (EtOH with LI) or "alcohol-drinkers without LI" (EtOH w/o LI) and we compared these groups to "non-drinkers" (no EtOH). When we examined patient blood from the EtOH with LI group we found the total number of EVs to be increased, along with an increase in miR-122 and let7f-two EV-associated miRNAs-and several inflammation-associating cytokines, such as interleukin (IL)-6 and IL-33. In contrast, all of the aforementioned readouts were found to be decreased in the EtOH w/o LI group. These novel data demonstrate that hepatocyte damage in alcohol-intoxicated trauma patients presenting with liver injury can be reflected by an increase in circulating serum EVs, their specific miR-"barcode" and the concomitant increase of systemic inflammatory markers IL-6 and IL-33. Anti-inflammatory effect of alcohol-drinking in EtOH w/o LI can be presented by a reduced number of hepato-derived EVs, no upregulation of IL-6 and IL-33, and a miR "barcode" different from patients presenting with liver injury. Background: Alcohol abuse is associated with (neuro)protective effects related to (head) injuries, and with negative effects regarding infection rates and survival in severely injured trauma patients (TP). Extracellular vesicles (EVs), which are released during tissue and/or cell injury, can contain a "barcode" including specific microRNAs (miRs) that uncover their origin. We examined whether EVs with a hepatic miR signature can be systemically measured, and whether they can indicate ongoing liver injury in alcohol-intoxicated TP and foretell clinical complications. Patients/Methods: We enrolled 35 TP and measured blood EVs, IL-6, TNF-alpha, IL-1beta, IL-10 and IL-33, alcohol (ethanol, EtOH) concentration (BAC), GLDH, GGT, AST, ALT, leukocytes, platelets, and bilirubin. Within circulating EVs we measured the expression levels of miR-122, let7f, miR21, miR29a, miR-155, and miR-146a. Patients of alcohol-drinkers were grouped into "alcohol drinkers with liver injury (LI)" (EtOH with LI) or "alcohol drinkers without LI" (EtOH w/o LI) and compared to "non-drinkers" (no EtOH). We assessed systemic injury characteristics and the outcome of hospitalization with regard to sepsis, septic shock, pneumonia, or mortality. Results: EtOH with LI patients had significantly increased rates of pneumonia vs. the EtOH w/o LI group. EVs, IL-6, and IL-33 levels were significantly increased in EtOH with LI vs. EtOH w/o LI group (p < 0.05). EV number correlated positively with ALT and IL-6 (p < 0.0001). Two miRs, miR-122 and let7f, were increased only in the blood EVs from the EtOH with LI group (p < 0.05). Five miRs, miR-122, let7f, miR-21, miR-29a, and miR-146a, were reduced in the blood EVs from the EtOH w/o LI group, vs. no EtOH (p < 0.05). Notably miR-122 correlated significantly with increased bilirubin levels in the EtOH with LI group (p < 0.05). Conclusions: Liver injury in alcohol-intoxicated TP is reflected by increased EV numbers, their specific miR barcode, and the correlated increase of systemic inflammatory markers IL-6 and IL-33. Interestingly, severely injured TP without liver injury were found to have a reduced number of liver-derived EVs, no observed inflammatory infiltration and reduced specific miR "barcode."

Alcohol Binge Reduces Systemic Leukocyte Activation and Pulmonary PMN Infiltration After Blunt Chest Trauma and Hemorrhagic Shock.

Blunt chest (thoracic) trauma (TxT) and hemorrhagic shock (HS)-induced local and systemic inflammation with increased neutrophil activity often result in an impaired organ function. Next to increasing the trauma risk, binge drinking causes anti-inflammatory effects due to immunomodulatory properties of alcohol (ethanol, EtOH). The impact of clinically relevant acute binge drinking scenario on local and systemic inflammatory changes, notably regarding the activity and longevity of leukocytes, has been analyzed in a combinatory trauma model of TxT + H/R. Twenty-four female Lewis rats (190-240 g) received alcohol (5 g/kg, 30%) or saline gavage. Two hours after alcohol gavage, TxT with subsequent HS (60 min) and resuscitation (TxT + H/R) were induced. Sham-operated animals underwent surgical procedures. Bronchoalveolar lavage fluid (BAL), lung tissue, and blood were harvested 2 h after resuscitation. Pulmonary infiltration with PMN, IL-6 gene expression, systemic PMN activation, neutrophil and monocyte apoptosis (caspase-3/7), and pyroptosis/inflammasome activation (caspase-1) were evaluated. Lung damage was evaluated by hematoxylin-eosin (H/E) staining and determination of the total protein content in BAL (ANOVA, p < 0.05 was significant). TxT + H/R-induced increases in IL-6, PMN infiltration and BAL-protein concentration were significantly reduced by EtOH; however, histological morphology changes after trauma remained unaltered by EtOH. TxT + H/R-induced systemic leukocyte activation (increased CD11b and CD31, reduced CD62L expression) as well as inflammasome activation in monocytes were significantly diminished by EtOH. Apoptosis was prolonged only in PMN after TxT + H/R and was further prolonged by EtOH, an effect that was observed in sham animals as a trend as well. Acute EtOH exposure inhibits the activation of circulating leukocytes after trauma compared to controls. These EtOH-driven systemic changes may be associated with reduced infiltration with PMN after trauma as well as reduced local tissue inflammation.

Ethyl pyruvate ameliorates hepatic injury following blunt chest trauma and hemorrhagic shock by reducing local inflammation, NF-kappaB activation and HMGB1 release.

BACKGROUND: The treatment of patients with multiple trauma including blunt chest/thoracic trauma (TxT) and hemorrhagic shock (H) is still challenging. Numerous studies show detrimental consequences of TxT and HS resulting in strong inflammatory changes, organ injury and mortality. Additionally, the reperfusion (R) phase plays a key role in triggering inflammation and worsening outcome. Ethyl pyruvate (EP), a stable lipophilic ester, has anti-inflammatory properties. Here, the influence of EP on the inflammatory reaction and liver injury in a double hit model of TxT and H/R in rats was explored. METHODS: Female Lewis rats were subjected to TxT followed by hemorrhage/H (60 min, 35±3 mm Hg) and resuscitation/R (TxT+H/R). Reperfusion was performed by either Ringer`s lactated solution (RL) alone or RL supplemented with EP (50 mg/kg). Sham animals underwent all surgical procedures without TxT+H/R. After 2h, blood and liver tissue were collected for analyses, and survival was assessed after 24h. RESULTS: Resuscitation with EP significantly improved haemoglobin levels and base excess recovery compared with controls after TxT+H/R, respectively (p<0.05). TxT+H/R-induced significant increase in alanine aminotransferase levels and liver injury were attenuated by EP compared with controls (p<0.05). Local inflammation as shown by increased gene expression of IL-6 and ICAM-1, enhanced ICAM-1 and HMGB1 protein expression and infiltration of the liver with neutrophils were also significantly attenuated by EP compared with controls after TxT+H/R (p<0.05). EP significantly reduced TxT+H/R-induced p65 activation in liver tissue. Survival rates improved by EP from 50% to 70% after TxT+H/R. CONCLUSIONS: These data support the concept that the pronounced local pro-inflammatory response in the liver after blunt chest trauma and hemorrhagic shock is associated with NF-κB. In particular, the beneficial anti-inflammatory effects of ethyl pyruvate seem to be regulated by the HMGB1/NF-κB axis in the liver, thereby, restraining inflammatory responses and liver injury after double hit trauma in the rat.

Ethyl pyruvate reduces acute lung damage following trauma and hemorrhagic shock via inhibition of NF-κB and HMGB1.

OBJECTIVE: After blunt thoracic trauma (TxT) and hemorrhagic shock with resuscitation (H/R) intense local inflammatory response and cell loss frequently impair the pulmonary function. Ethyl pyruvate (EP) has been reported to improve the pathophysiologic derangements in models of acute inflammation. Here, we studied the effects of EP on inflammation and lung damage after TxT+H/R. METHODS: Twenty four female Lewis rats (180-240g) were randomly divided into 3 groups: two groups underwent TxT followed by hemorrhagic shock (35±3mmHg) for 60min and resuscitation with either Ringers-Lactat (RL) alone or RL supplemented with EP (EP, 50mg/kg). Sham operated animals underwent surgical procedures. Two hours later bronchoalveolar lavage fluid (BAL), lung tissue and blood were collected for analyses. RESULTS: EP significantly improved pO2 levels compared to RL after TxT+H/R. TxT+H/R induced elevated levels of lactate dehydrogenase, total protein concentration in BAL and lung damage as evidenced by lung histology; these effects were significantly reduced by EP. Local inflammatory markers, lung TNF-alpha protein levels and infiltration with polymorphonuclear leukocytes (PMNL) significantly decreased in EP vs. RL group after TxT+H/R. Indicators of apoptosis as reduced BCL-2 and increased FAS gene expression after TxT+H/R were significantly increased or decreased, respectively, by EP after TxT+H/R. EP reduced TxT+H/R-induced p65 phosphorylation, which was concomitant with reduced HMGB1 levels in lung sections. CONCLUSIONS: Taken together, TxT+H/R induced strong inflammatory response and apoptotic changes as well as lung injury which were markedly diminished by EP. Our results suggest that this might be mediated via NF-κB and/or HMGB1 dependent mechanism.

Acute Alcohol Binge Deteriorates Metabolic and Respiratory Compensation Capability After Blunt Chest Trauma Followed by Hemorrhagic Shock-A New Research Model.

BACKGROUND: The clinical relevance of blunt (thoracic) chest trauma (TxT) and hemorrhagic shock is indisputable due to the high prevalence of this injury type, as well as its close association with mortality and/or preventable deaths. Furthermore, there is an ongoing discussion about the influence of alcohol in trauma patients. Thus, we established a model of TxT followed by hemorrhagic shock with resuscitation (H/R) in alcohol-intoxicated rats. METHODS: Depending on group allocation, 12 (subacute) or 2 (acute) hours before experimentation, the animals received a single oral dose of alcohol (ethanol [EtOH]) or saline (NaCl) followed by TxT, hemorrhagic shock (35 ± 3 mm Hg), and resuscitation (TxT + H/R). Arterial blood gas analyses and continuous monitoring of blood pressure were performed during the experimentation period. Survival during the experimentation procedure was determined. RESULTS: Subacute and acute EtOH group exhibited lower baseline mean arterial blood pressure values compared with the corresponding NaCl group, respectively. Both EtOH groups showed lower maximal bleed-out volume, which was necessary to induce hemorrhagic shock compared to NaCl groups, and the recovery during the resuscitation period was attenuated. During the experimentation in all groups, a trend to acidic pH was observed. Acute EtOH group showed lowest pH values compared to all other groups. Higher pCO2 values were observed in both EtOH groups. All groups developed negative base excess and decreasing HCO3- values until the end of hemorrhagic shock and showed increasing base excess and HCO3- values during resuscitation. Significantly higher mortality rate was found in the acute EtOH group. CONCLUSIONS: This study indicates that alcohol limits the metabolic and respiratory compensation capability, thereby promoting mortality.