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Background Maintaining physiological levels of hydrogen sulfide (H2S) during ischemia is necessary to limit injury to the heart. Due to the anti-inflammatory effects of H2S, we proposed that the H2S donor, Na2S, would attenuate myocardial injury through upregulation of ‘protective’ microRNA (miR)-21 and suppression of the inflammasome, a macromolecular structure that amplifies inflammation and mediates further injury. Methods and Results Na2S-induced miR-21 expression was measured by qPCR in adult primary rat cardiomyocytes and in the mouse heart. We measured inflammasome formation and activity in cardiomyocytes challenged with lipopolysaccharide (LPS) and adenosine-tri-phosphate (ATP) or simulated ischemia/reoxygenation; and in the heart following regional myocardial ischemia/reperfusion (I/R), in the presence or absence of Na2S. To assess the direct anti-inflammatory effects of H2S in vivo, we utilized a peritonitis model by way of intraperitoneal injection of zymosan A. Na2S attenuated inflammasome formation and activity - measured by counting cytoplasmic aggregates of the scaffold protein Apoptosis Speck-like protein containing a Caspase-recruitment domain (ASC; −57%) and caspase-1 activity (−50%) in isolated cardiomyocytes and in the mouse heart (all P<0.05). Na2S also inhibited apoptosis (−38%) and necrosis (−43%) in cardiomyocytes in vitro and reduced myocardial infarct size (−63%) following I/R injury in vivo (all P<0.05). These protective effects were absent in cells treated with antagomiR-21 and in miR-21 KO mice. Na2S also limited the severity of inflammasome-dependent inflammation in the model of peritonitis (P<0.05) in wild-type but not in miR-21 KO mice. Conclusions Na2S induces cardioprotective effects through miR-21-dependent attenuation of ischemic and inflammatory injury in cardiomyocytes.

Objectives: Identify the metabolites that are increased in the plasma of severely injured patients that developed ARDS versus severely injured patients that did not, and assay if these increased metabolites prime pulmonary sequestration of neutrophils (PMNs) and induce pulmonary sequestration in an animal model of ARDS. We hypothesize that metabolic derangement due to advanced shock in critically injured patients leads to the PMNs, which serves as the first event in the ARDS. Summary of Background Data: Intracellular metabolites accumulate in the plasma of severely injured patients.Methods: Untargeted metabolomics profiling of 67 critically injured patients was completed to establish a metabolic signature associated with ARDS development. Metabolites that significantly increased were assayed for PMN priming activity in vitro. The metabolites that primed PMNs were tested in a 2-event animal model of ARDS to identify a molecular link between circulating metabolites and clinical risk for ARDS. Results: After controlling for confounders, 4 metabolites significantly increased: creatine, dehydroascorbate, fumarate, and succinate in trauma patients who developed ARDS (P < 0.05). Succinate alone primed the PMN oxidase in vitro at physiologically relevant levels. Intravenous succinate-induced PMN sequestration in the lung, a first event, and followed by intravenous lipopolysaccharide, a second event, resulted in ARDS in vivo requiring PMNs. SUCNR1 inhibition abrogated PMN priming, PMN sequestration, and ARDS. Conclusion: Significant increases in plasma succinate post-injury may serve as the first event in ARDS. Targeted inhibition of the SUCNR1 may decrease ARDS development from other disease states to prevent ARDS globally.

ImportanceAortic occlusion (AO) is a lifesaving therapy for the treatment of severe traumatic hemorrhagic shock; however, there remains controversy whether AO should be accomplished via resuscitative thoracotomy (RT) or via endovascular balloon occlusion of the aorta (REBOA) in zone 1.ObjectiveTo compare outcomes of AO via RT vs REBOA zone 1.Design, Setting, and ParticipantsThis was a comparative effectiveness research study using a multicenter registry of postinjury AO from October 2013 to September 2021. AO via REBOA zone 1 (above celiac artery) was compared with RT performed in the emergency department of facilities experienced in both procedures and documented in the prospective multicenter Aortic Occlusion for Resuscitation in Trauma and Acute Care Surgery (AORTA) registry. Propensity score matching (PSM) with exact institution matching was used, in addition to subgroup multivariate analysis to control for confounders. The study setting included the ED, where AO via RT or REBOA was performed, and participants were adult trauma patients 16 years or older.ExposuresAO via REBOA zone 1 vs RT.Main Outcomes and MeasuresThe primary outcome was survival. Secondary outcomes were ventilation-free days (VFDs), intensive care unit (ICU)–free days, discharge Glasgow Coma Scale score, and Glasgow Outcome Score (GOS).ResultsA total of 991 patients (median [IQR] age, 32 [25-48] years; 808 male individuals [81.9%]) with a median (IQR) Injury Severity Score of 29 (18-50) were included. Of the total participants, 306 (30.9%) had AO via REBOA zone 1, and 685 (69.1%) had AO via RT. PSM selected 112 comparable patients (56 pairs). REBOA zone 1 was associated with a statistically significant lower mortality compared with RT (78.6% [44] vs 92.9% [52]; P = .03). There were no significant differences in VFD greater than 0 (REBOA, 18.5% [10] vs RT, 7.1% [4]; P = .07), ICU-free days greater than 0 (REBOA, 18.2% [10] vs RT, 7.1% [4]; P = .08), or discharge GOS of 5 or more (REBOA, 7.5% [4] vs RT, 3.6% [2]; P = .38). Multivariate analysis confirmed the survival benefit of REBOA zone 1 after adjustment for significant confounders (relative risk [RR], 1.25; 95% CI, 1.15-1.36). In all subgroup analyses (cardiopulmonary resuscitation on arrival, traumatic brain injury, chest injury, pelvic injury, blunt/penetrating mechanism, systolic blood pressure ≤60 mm Hg on AO initiation), REBOA zone 1 offered an either similar or superior survival.Conclusions and RelevanceResults of this comparative effectiveness research suggest that REBOA zone 1 provided better or similar survival than RT for patients requiring AO postinjury. These findings provide the ethically necessary equipoise between these therapeutic approaches to allow the planning of a randomized controlled trial to establish the safety and effectiveness of REBOA zone 1 for AO in trauma resuscitation.

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