Acute lung injury (ALI) is a common cause of morbidity in patients after severe injury due to dysregulated inflammation, which is believed to be driven by gut‐derived inflammatory mediators carried ...via mesenteric lymph (ML). We have previously demonstrated that nano‐sized extracellular vesicles, called exosomes, secreted into ML after trauma/hemorrhagic shock (T/HS) have the potential to activate immune cells in vitro. Here, we assess the function of ML exosomes in the development of T/HS‐induced ALI and the role of TLR4 in the ML exosome‐mediated inflammatory response. ML exosomes isolated from rats subjected to T/HS stimulated NF‐KB activation and caused proinflammatory cytokine production in alveolar macrophages. In vivo experiments revealed that intravenous injection of exosomes harvested after T/HS, but not before shock, caused recruitment of inflammatory cells in the lung, increased vascular permeability, and induced histologic ALI in naive mice. The exosome‐depleted supernatant of ML had no effect on in vitro and in vivo inflammatory responses. We also demonstrated that both pharmacologic inhibition and genetic knockout of TLR4 completely abolished ML exosome‐induced cytokine production in macrophages. Thus, our findings define the critical role of exosomes secreted into ML as a critical mediator of T/HS‐induced ALI through macrophage TLR4 activation.—Kojima, M., Gimenes‐Junior, J. A., Chan, T. W., Eliceiri, B. P., Baird, A., Costantini, T. W., Coimbra, R. Exosomes in postshock mesenteric lymph are key mediators of acute lung injury triggering the macrophage activation via Toll‐like receptor 4. FASEB J. 32,97‐110 (2018). www.fasebj.org
•Accurate cannulation is essential for extracorporeal cardiopulmonary resuscitation.•Japanese multicenter data were analyzed with propensity score matching.•Real-time ultrasound-guided cannulation ...was associated with shorter cannulation time.
Extracorporeal cardiopulmonary resuscitation (ECPR), a bridge to treatments for cardiac arrest patients, can be technically challenging and requires expertise. While ultrasound guidance is frequently used for vascular access, its effects on cannulation time in patients treated with ECPR are poorly defined. We hypothesized that real-time ultrasound guidance would contribute to faster and safer cannulation for ECPR.
This nationwide, multicenter, retrospective study analyzed data from 36 Japanese institutions. Patients who were over age 18 years and underwent ECPR between January 1, 2013, and December 31, 2018, were included. Patients who underwent open surgical vascular access were excluded. Cannulation time and outcomes of patients who underwent real-time ultrasound-guided cannulation (i.e., ultrasound-guided group) were compared to those cannulated without the use of real-time ultrasound guidance (control group) using propensity score matching analysis.
The ultrasound-guided group comprised 510 cases, whereas the control group comprised 941 cases. Of those, 443 propensity score-matched pairs were evaluated. Cannulation time in the ultrasound-guided group was 2.5 minutes shorter than in the control group difference, −2.5 minutes; 95% Confidence interval (CI), −3.7 to −1.3, p < 0.001. The incidence of catheter-related complications and the incidence of the poor neurological outcomes (Cerebral Performance Category ≥3) did not differ between groups Odds ratio (OR), 1.51; 95% CI, 0.64–3.74; OR, 1.08; 95% CI, 0.83–1.59.
Real-time ultrasound-guided cannulation was associated with shorter cannulation time of ECPR.
Empiric enoxaparin dosing is inadequate for most trauma patients, leading to below target initial anti-Xa levels and requiring dose adjustment for optimal venous thromboembolism prophylaxis. We ...hypothesize that patient factors affecting initial anti-Xa levels can be identified based on drug pharmacokinetics, allowing creation of a new dosing protocol that will provide a higher percentage of in-target (0.2-0.4 IU/mL) patients at initial anti-Xa level assessment.
Records of 318 trauma patients were evaluated, and NONMEM and PSN software were used to analyze 11 variables for their effects on anti-Xa levels. Computer modeling was used to select a new dosing protocol, which was implemented on the trauma service as a quality improvement project. The first 145 patients appropriately enrolled were assessed for response and complications.
Only 29.5% of the pre-intervention group had initial anti-Xa levels in the appropriate prophylactic range (). Levels were most strongly influenced by patient weight, outweighing contributions from all other variables. A new regimen for initial dosing was therefore designed with three weight-defined categories for ease of administration. The post-intervention group showed an increase in in-target initial anti-Xa levels to 74.5% (p < 0.001), with a corresponding decrease in subprophylactic patients from 68.0% to 20.7%. There was an increase in supraprophylactic levels to 4.8%, but no supraprophylactic patients had hemorrhagic complications.(Figure is included in full-text article.) CONCLUSIONS: Implementation of a new, categorized, weight-based enoxaparin dosing protocol was safe and significantly improved the percentage of trauma patients with in-target anti-Xa levels on initial assessment. Further studies are needed to determine whether such dosing decreases venous thromboembolism rates.
Therapeutic/care management study, level II.
BACKGROUND
Traumatic brain injury (TBI) is a leading cause of morbidity and mortality in trauma patients worldwide. Brain injury is associated with significant inflammation, both within the brain and ...in the peripheral organs. This inflammatory response in TBI leads to a secondary injury, worsening the effects of the original brain injury. Serotonin is also linked to inflammation in the intestine and inflammatory bowel disease, but its role in the gut-brain axis is not known. We hypothesized that using fluoxetine to block serotonin reuptake would reduce organ inflammation and improve outcomes after TBI.
METHODS
C57/B6 mice were given a severe TBI using a controlled cortical impact. To measure intestinal permeability, a piece of terminal ileum was resected, the lumen was filled with 4-kDa fluorescein isothiocyanate (FITC)-dextran, and the ends were tied. The intestinal segment was submerged in buffer and fluorescence in the buffer measured over time. To measure lung permeability, 70-kDa FITC-dextran is injected retro-orbitally. Thirty minutes later, the left lung was homogenized and the fluorescence was measured. To measure performance on the rota-rod, mice were placed on a spinning rod, and the time to fall off was measured. Those treated with fluoxetine received a single dose of 5 mg/kg via intraperitoneal injection immediately after injury.
RESULTS
Traumatic brain injury was associated with an increase in intestinal permeability to FITC-dextran, increased lung vascular permeability, and worse performance on the rota-rod. Fluoxetine significantly reduced lung and intestinal permeability after TBI and improved performance on the rota-rod after TBI.
CONCLUSION
Use of fluoxetine has the potential to reduce lung injury and improve motor coordination in severe TBI patients. Further study will be needed to elucidate the mechanism behind this effect.
Venous thromboembolism (VTE) is a significant cause of morbidity and mortality during recovery from injury and can result in significant healthcare costs. Despite advances in the past several decades ...in our approach to VTE prophylaxis after injury, opportunities exist to improve the delivery and implementation of optimal VTE prophylaxis. Here, we aim to identify consensus research questions related to VTE across all NTRAP Delphi expert panels to further guide the research agenda aimed at preventing VTE after injury.
This is a secondary analysis of consensus-based research priorities that were collected using a Delphi methodology by 11 unique NTRAP panels that were charged with unique topic areas across the spectrum of injury care. The database of questions was queried for the keywords "VTE", "venous thromboembo", and "DVT", then grouped into relevant topic areas.
There were 86 VTE-related research questions identified across 9 NTRAP panels. 85 questions reached consensus with 24 rated high priority, 60 medium priority and 1 low priority. Questions related to the timing of VTE prophylaxis (n = 17) were most common, followed by questions related to risk factors for the development of VTE (n = 16), the effects of tranexamic acid on VTE (n = 11), the approach to dosing of pharmacologic prophylaxis (n = 8), as well as the pharmacologic prophylactic medication choice for optimal VTE prophylaxis (n = 6).
NTRAP panelists identified 85 consensus-based research questions that should drive dedicated extramural research funding opportunities to support quality studies aimed at optimizing VTE prophylaxis after injury.
Original Research, IV.
Ultrasonography for trauma is a widely used tool in the initial evaluation of trauma patients with complete ultrasonography of trauma (CUST) demonstrating equivalence to computed tomography (CT) for ...detecting clinically significant abdominal hemorrhage. Initial reports demonstrated high sensitivity of CUST for the bedside diagnosis of pneumothorax. We hypothesized that the sensitivity of CUST would be greater than initial supine chest radiograph (CXR) for detecting pneumothorax.
A retrospective analysis of patients diagnosed with pneumothorax from 2018 through 2020 at a Level I trauma center was performed. Patients included had routine supine CXR and CUST performed prior to intervention as well as confirmatory CT imaging. All CUST were performed during the initial evaluation in the trauma bay by a registered sonographer. All imaging was evaluated by an attending radiologist. Subgroup analysis was performed after excluding occult pneumothorax. Immediate tube thoracostomy was defined as tube placement with confirmatory CXR within 8 hours of admission.
There were 568 patients screened with a diagnosis of pneumothorax, identifying 362 patients with a confirmed pneumothorax in addition to CXR, CUST, and confirmatory CT imaging. The population was 83% male, had a mean age of 45 years, with 85% presenting due to blunt trauma. Sensitivity of CXR for detecting pneumothorax was 43%, while the sensitivity of CUST was 35%. After removal of occult pneumothorax (n = 171), CXR was 78% sensitive, while CUST was 65% sensitive (p < 0.01). In this subgroup, CUST had a false-negative rate of 36% (n = 62). Of those patients with a false-negative CUST, 50% (n = 31) underwent tube thoracostomy, with 85% requiring immediate placement.
Complete ultrasonography of trauma performed on initial trauma evaluation had lower sensitivity than CXR for identification of pneumothorax including clinically significant pneumothorax requiring tube thoracostomy. Using CUST as the primary imaging modality in the initial evaluation of chest trauma should be considered with caution.
Diagnostic Test study, Level IV.
Exosomes are extracellular vesicles that act as endogenous mediators of the immune response. We have previously shown that exosomes released into mesenteric lymph (ML) following trauma ...(T)/hemorrhagic shock (HS) induce proinflammatory cytokine production in macrophages and are involved in the pathogenesis of postshock acute lung injury. However, the cellular origin of ML exosomes and their role in the posttrauma immune response remains unclear. We hypothesized that exosomes released from damaged-intestinal epithelial cells contribute to posttrauma immune dysfunction by altering the function of dendritic cells (DCs), key regulators of the adaptive immunity.
Male rats underwent cannulation of the femoral artery, jugular vein and ML duct. T/HS was induced by laparotomy and 60 minutes of hemorrhagic shock followed by resuscitation. The ML was collected before (preshock) and after T/HS (post-T/HS) for isolation of exosomes. Surface epitopes of exosomes isolated from ML were assessed by flow cytometry to determine their cellular origin and phenotypic changes. The immunomodulatory effects of ML exosomes on DCs were assessed by Annexin V apoptosis assay, expression of costimulatory molecules, and antigen-presenting capacity to lymphocytes.
Exosomes isolated from ML highly expressed CD63 (exosome marker) and epithelial cell-specific marker, suggesting their derivation from intestinal epithelial cells. The expression of immunomodulatory molecules, such as major histocompatibility complex class II and Fas ligand on ML exosomes, was significantly increased after T/HS. Coincubation of DCs with exosomes isolated from ML after T/HS increased DC apoptosis twofold compared with preshock ML exosomes. Furthermore, post-T/HS ML exosomes significantly suppressed lipopolysaccharide-mediated expression of CD80 and CD86 on DCs as well as decreased their antigen-presenting capacity to induce lymphocytes proliferation.
Gut epithelial cells release immunomodulatory exosomes into the ML after T/HS and resuscitation. Mesenteric lymph exosomes may be critical mediators of posttraumatic immunosuppression causing depletion and dysfunction of DCs.
Trauma/hemorrhagic shock (T/HS) causes the release of pro-inflammatory mediators into the mesenteric lymph (ML), triggering a systemic inflammatory response and acute lung injury (ALI). Direct and ...pharmacologic vagal nerve stimulation prevents gut barrier failure and alters the biologic activity of ML after injury. We hypothesize that treatment with a pharmacologic vagal agonist after T/HS would attenuate the biologic activity of ML and prevent ALI.
ML was collected from male Sprague-Dawley rats after T/HS, trauma-sham shock (T/SS) or T/HS with administration of the pharmacologic vagal agonist CPSI-121. ML samples from each experimental group were injected into naïve mice to assess biologic activity. Blood samples were analyzed for changes in STAT3 phosphorylation (pSTAT3). Lung injury was characterized by histology, permeability and immune cell recruitment.
T/HS lymph injected in naïve mice caused a systemic inflammatory response characterized by hypotension and increased circulating monocyte pSTAT3 activity. Injection of T/HS lymph also resulted in ALI, confirmed by histology, lung permeability and increased recruitment of pulmonary macrophages and neutrophils to lung parenchyma. CPSI-121 attenuated T/HS lymph-induced systemic inflammatory response and ALI with stable hemodynamics and similar monocyte pSTAT3 levels, lung histology, lung permeability and lung immune cell recruitment compared to animals injected with lymph from T/SS.
Treatment with CPSI-121 after T/HS attenuated the biologic activity of the ML and decreased ALI. Given the superior clinical feasibility of utilizing a pharmacologic approach to vagal nerve stimulation, CPSI-121 is a potential treatment strategy to limit end organ dysfunction after injury.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Vagal nerve stimulation (VNS) has been shown to limit intestinal inflammation following injury; however, a direct connection between vagal terminals and resident intestinal immune cells has yet to be ...identified. We have previously shown that enteric glia cell (EGC) expression is increased after injury through a vagal-mediated pathway to help restore gut barrier function. We hypothesize that EGCs modulate immune cell recruitment following injury and relay vagal anti-inflammatory signals to resident immune cells in the gut. EGCs were selectively ablated from an isolated segment of distal bowel with topical application of benzalkonium chloride (BAC) in male mice. Three days following BAC application, mice were subjected to an ischemia-reperfusion injury (I/R) by superior mesenteric artery occlusion for 30 min. VNS was performed in a separate cohort of animals. EGC
and EGC
segments were compared utilizing histology, flow cytometry, immunohistochemistry, and intestinal permeability. VNS significantly reduced immune cell recruitment after I/R injury in EGC
segments with cell percentages similar to sham. VNS failed to limit immune cell recruitment in EGC
segments. Histologic evidence of gut injury was diminished with VNS application in EGC
segments, whereas EGC
segments showed features of more severe injury. Intestinal permeability increased following I/R injury in both EGC
and EGC
segments. Permeability was significantly lower after VNS application compared with injury alone in EGC
segments only (95.1 ± 30.0 vs. 217.6 ± 21.7 μg/ml,
< 0.05). Therefore, EGC ablation uncouples the protective effects of VNS, suggesting that vagal-mediated signals are translated to effector cells through EGCs.
Intestinal inflammation is initiated by local immune cell activation and epithelial barrier breakdown, resulting in the production of proinflammatory mediators with subsequent leukocyte recruitment. Vagal nerve stimulation (VNS) has been shown to limit intestinal inflammation following injury; however, direct connection between vagal terminals and resident intestinal immune cells has yet to be identified. Here, we demonstrate that intact enteric glia cells are required to transmit the gut anti-inflammatory effects of VNS.
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