TRPV4 Regulates the Macrophage Metabolic Response to Limit Sepsis-induced Lung Injury.

Sepsis is a systemic inflammatory response that requires effective macrophage metabolic functions to resolve ongoing inflammation. Previous work showed that the mechanosensitive cation channel, transient receptor potential vanilloid 4 (TRPV4), mediates macrophage phagocytosis and cytokine production in response to lung infection. Here, we show that TRPV4 regulates glycolysis in a stiffness-dependent manner by augmenting macrophage glucose uptake by GLUT1. In addition, TRPV4 is required for LPS-induced phagolysosome maturation in a GLUT1-dependent manner. In a cecal slurry mouse model of sepsis, TRPV4 regulates sepsis-induced glycolysis as measured by BAL fluid (BALF) lactate and sepsis-induced lung injury as measured by BALF total protein and lung compliance. TRPV4 is necessary for bacterial clearance in the peritoneum to limit sepsis-induced lung injury. It is interesting that BALF lactate is increased in patients with sepsis compared with healthy control participants, supporting the relevance of lung cell glycolysis to human sepsis. These data show that macrophage TRPV4 is required for glucose uptake through GLUT1 for effective phagolysosome maturation to limit sepsis-induced lung injury. Our work presents TRPV4 as a potential target to protect the lung from injury in sepsis.

Forecasting disease trajectories in critical illness: comparison of probabilistic dynamic systems to static models to predict patient status in the intensive care unit.

OBJECTIVE: Conventional prediction models fail to integrate the constantly evolving nature of critical illness. Alternative modelling approaches to study dynamic changes in critical illness progression are needed. We compare static risk prediction models to dynamic probabilistic models in early critical illness. DESIGN: We developed models to simulate disease trajectories of critically ill COVID-19 patients across different disease states. Eighty per cent of cases were randomly assigned to a training and 20% of the cases were used as a validation cohort. Conventional risk prediction models were developed to analyse different disease states for critically ill patients for the first 7 days of intensive care unit (ICU) stay. Daily disease state transitions were modelled using a series of multivariable, multinomial logistic regression models. A probabilistic dynamic systems modelling approach was used to predict disease trajectory over the first 7 days of an ICU admission. Forecast accuracy was assessed and simulated patient clinical trajectories were developed through our algorithm. SETTING AND PARTICIPANTS: We retrospectively studied patients admitted to a Cleveland Clinic Healthcare System in Ohio, for the treatment of COVID-19 from March 2020 to December 2022. RESULTS: 5241 patients were included in the analysis. For ICU days 2-7, the static (conventional) modelling approach, the accuracy of the models steadily decreased as a function of time, with area under the curve (AUC) for each health state below 0.8. But the dynamic forecasting approach improved its ability to predict as a function of time. AUC for the dynamic forecasting approach were all above 0.90 for ICU days 4-7 for all states. CONCLUSION: We demonstrated that modelling critical care outcomes as a dynamic system improved the forecasting accuracy of the disease state. Our model accurately identified different disease conditions and trajectories, with a <10% misclassification rate over the first week of critical illness.

Effect of Ethanol-exposure on Innate Immune Response in Sepsis.

Alcohol use disorder, reported by one in eight critically ill patients, is a risk factor for death in sepsis patients. Sepsis, the leading cause of death kills over 270,000 patients in the United States alone and remains without targeted therapy. Immune response in sepsis transitions from an early hyper-inflammation to persistent inflammation and immunosuppression and multiple organ dysfunction during late sepsis. Innate immunity is the first line of defense against pathogen invasion. Ethanol exposure is known to impair innate and adaptive immune response and bacterial clearance in sepsis patients. Specifically, ethanol-exposure is known to modulate every aspect of innate immune response with and without sepsis. Multiple molecular mechanisms are implicated in causing dysregulated immune response in ethanol-exposure with sepsis, but targeted treatments have remained elusive. In this manuscript, we outline the effects of ethanol-exposure on various innate immune cell types in general and during sepsis.

Nonbronchoscopic Bronchoalveolar Lavage Improves Respiratory Culture Accuracy in Critically Ill Patients.

OBJECTIVES: Diagnosis of pneumonia is challenging in critically ill, intubated patients due to limited diagnostic modalities. Endotracheal aspirate (EA) cultures are standard of care in many ICUs; however, frequent EA contamination leads to unnecessary antibiotic use. Nonbronchoscopic bronchoalveolar lavage (NBBL) obtains sterile, alveolar cultures, avoiding contamination. However, paired NBBL and EA sampling in the setting of a lack of gold standard for airway culture is a novel approach to improve culture accuracy and limit antibiotic use in the critically ill patients. DESIGN: We designed a pilot study to test respiratory culture accuracy between EA and NBBL. Adult, intubated patients with suspected pneumonia received concurrent EA and NBBL cultures by registered respiratory therapists. Respiratory culture microbiology, cell counts, and antibiotic prescribing practices were examined. SETTING: We performed a prospective pilot study at the Cleveland Clinic Main Campus Medical ICU in Cleveland, Ohio for 22 months from May 2021 through March 2023. PATIENTS OR SUBJECTS: Three hundred forty mechanically ventilated patients with suspected pneumonia were screened. Two hundred fifty-seven patients were excluded for severe hypoxia (Fio2 ≥ 80% or positive end-expiratory pressure ≥ 12 cm H2O), coagulopathy, platelets less than 50,000, hemodynamic instability as determined by the treating team, and COVID-19 infection to prevent aerosolization of the virus. INTERVENTIONS: All 83 eligible patients were enrolled and underwent concurrent EA and NBBL. MEASUREMENTS AND MAIN RESULTS: More EA cultures (42.17%) were positive than concurrent NBBL cultures (26.51%, p = 0.049), indicating EA contamination. The odds of EA contamination increased by eight-fold 24 hours after intubation. EA was also more likely to be contaminated with oral flora when compared with NBBL cultures. There was a trend toward decreased antibiotic use in patients with positive EA cultures if paired with a negative NBBL culture. Alveolar immune cell populations were recovered from NBBL samples, indicating successful alveolar sampling. There were no major complications from NBBL. CONCLUSIONS: NBBL is more accurate than EA for respiratory cultures in critically ill, intubated patients. NBBL provides a safe and effective technique to sample the alveolar space for both clinical and research purposes.

Adjunctive Vasopressors in Patients with Septic Shock: Protocol for a Systematic Review and Meta-Analysis.

Background: Over one-third of patients with septic shock have adjunctive vasopressors added to first-line vasopressors. However, no randomized trial has detected improved mortality with adjunctive vasopressors. Published systematic reviews and meta-analysis have sought to inform the use of adjunctive vasopressors, yet each published review has limitations that hinder its interpretation. This review aims to overcome the limitations of previous reviews by systematically synthesizing the direct evidence for adjunctive vasopressor therapy use in adult patients with septic shock. Methods: We will conduct a systematic review and meta-analysis of randomized controlled trials evaluating adjunctive vasopressors (vasopressin analogues, angiotensin II, hydroxocobalamin, methylene blue, and catecholamine analogues) in adult patients with septic shock. Relevant studies will be identified through comprehensive searches of MEDLINE, Embase, CENTRAL, and reference lists of previous systematic reviews. Only randomized trials comparing adjunctive vasopressors (>75% of subjects on vasopressors at enrollment) to standard care vasopressors in adults with septic shock (>75% of subjects having septic shock) will be included. Titles and abstracts will be screened, full-text articles assessed for eligibility, and data extracted from included studies. Outcomes of interest include short-term mortality, intermediate-term mortality, kidney replacement therapy, digital/peripheral ischemia, and venous thromboembolism. Pairwise meta-analysis using a random-effects model will be utilized to estimate the risk ratio for the outcomes. Risk of bias will be adjudicated with the Cochrane Risk of Bias 2 tool, and GRADE will be used to rate the certainty of the body of evidence. Discussion: Although adjunctive vasopressors are commonly used in patients with septic shock their effect on patient-important outcomes is unclear. This study is planned to use rigorous systematic review methodology, including strict adhere to established guidelines, in order to overcome limitations of previously-published reviews and inform clinical practice and treatment guidelines for the use of adjunctive vasopressors in adults with septic shock. Systematic review registration: PROSPERO CRD4202327984.

Altered anti-viral immune responses in monocytes in overweight heavy drinkers.

Alcohol abuse causes increased susceptibility to respiratory syndromes like bacterial pneumonia and viral infections like SARS-CoV-2. Heavy drinkers (HD) are at higher risk of severe COVID-19 if they are also overweight, yet the molecular mechanisms are unexplored. Single-cell RNA-sequencing (scRNA-seq) was performed on peripheral blood mononuclear cells from lean or overweight HD and healthy controls (HC) after challenge with a dsRNA homopolymer (PolyI:C) to mimic a viral infection and/or with lipopolysaccharide (LPS). All monocyte populations responded to both PolyI:C and LPS with pro-inflammatory gene expression. However, the expression of interferon-stimulated genes, essential for inhibiting viral pathogenesis, was greatly reduced in overweight patients. Interestingly, the number of upregulated genes in response to the PolyI:C challenge was far greater in monocytes from HD compared to HC, including much stronger pro-inflammatory cytokine and interferon-γ signaling responses. These results suggest that increased body weight reduced anti-viral responses while heavy drinking increased pro-inflammatory cytokines.

Echocardiographic profiles and hemodynamic response after vasopressin initiation in septic shock: A cross-sectional study.

PURPOSE: Vasopressin, used as a catecholamine adjunct, is a vasoconstrictor that may be detrimental in some hemodynamic profiles, particularly left ventricular (LV) systolic dysfunction. This study tested the hypothesis that echocardiographic parameters differ between patients with a hemodynamic response after vasopressin initiation and those without a response. METHODS: This retrospective, single-center, cross-sectional study included adults with septic shock receiving catecholamines and vasopressin with an echocardiogram performed after shock onset but before vasopressin initiation. Patients were grouped by hemodynamic response, defined as decreased catecholamine dosage with mean arterial pressure ≥ 65 mmHg six hours after vasopressin initiation, with echocardiographic parameters compared. LV systolic dysfunction was defined as LV ejection fraction (LVEF) <45%. RESULTS: Of 129 included patients, 72 (56%) were hemodynamic responders. Hemodynamic responders, versus non-responders, had higher LVEF (61% [55%,68%] vs. 55% [40%,65%]; p = 0.02) and less-frequent LV systolic dysfunction (absolute difference  -16%; 95% CI -30%,-2%). Higher LVEF was associated with higher odds of hemodynamic response (for each LVEF 10%, response OR 1.32; 95% CI 1.04-1.68). Patients with LV systolic dysfunction, versus without LV systolic dysfunction, had higher mortality risk (HR(t) = e[0.81-0.1*t]; at t = 0, HR 2.24; 95% CI 1.08-4.64). CONCLUSIONS: Pre-drug echocardiographic profiles differed in hemodynamic responders after vasopressin initiation versus non-responders.

Dysregulated cellular redox status during hyperammonemia causes mitochondrial dysfunction and senescence by inhibiting sirtuin-mediated deacetylation.

Perturbed metabolism of ammonia, an endogenous cytotoxin, causes mitochondrial dysfunction, reduced NAD+ /NADH (redox) ratio, and postmitotic senescence. Sirtuins are NAD+ -dependent deacetylases that delay senescence. In multiomics analyses, NAD metabolism and sirtuin pathways are enriched during hyperammonemia. Consistently, NAD+ -dependent Sirtuin3 (Sirt3) expression and deacetylase activity were decreased, and protein acetylation was increased in human and murine skeletal muscle/myotubes. Global acetylomics and subcellular fractions from myotubes showed hyperammonemia-induced hyperacetylation of cellular signaling and mitochondrial proteins. We dissected the mechanisms and consequences of hyperammonemia-induced NAD metabolism by complementary genetic and chemical approaches. Hyperammonemia inhibited electron transport chain components, specifically complex I that oxidizes NADH to NAD+ , that resulted in lower redox ratio. Ammonia also caused mitochondrial oxidative dysfunction, lower mitochondrial NAD+ -sensor Sirt3, protein hyperacetylation, and postmitotic senescence. Mitochondrial-targeted Lactobacillus brevis NADH oxidase (MitoLbNOX), but not NAD+ precursor nicotinamide riboside, reversed ammonia-induced oxidative dysfunction, electron transport chain supercomplex disassembly, lower ATP and NAD+ content, protein hyperacetylation, Sirt3 dysfunction and postmitotic senescence in myotubes. Even though Sirt3 overexpression reversed ammonia-induced hyperacetylation, lower redox status or mitochondrial oxidative dysfunction were not reversed. These data show that acetylation is a consequence of, but is not the mechanism of, lower redox status or oxidative dysfunction during hyperammonemia. Targeting NADH oxidation is a potential approach to reverse and potentially prevent ammonia-induced postmitotic senescence in skeletal muscle. Since dysregulated ammonia metabolism occurs with aging, and NAD+ biosynthesis is reduced in sarcopenia, our studies provide a biochemical basis for cellular senescence and have relevance in multiple tissues.

Alcohol and Immunology: Mechanisms of multi-organ damage. Summary of the 2022 alcohol and Immunology research interest group (AIRIG) meeting.

On October 26th, 2022 the annual Alcohol and Immunology Research Interest Group (AIRIG) meeting was held as a satellite symposium at the annual meeting of the Society for Leukocyte Biology in Hawaii. The 2022 meeting focused broadly on the immunological consequences of acute, chronic, and prenatal alcohol exposure and how these contribute to damage in multiple organs and tissues. These included alcohol-induced neuroinflammation, impaired lung immunity, intestinal dysfunction, and decreased anti-microbial and anti-viral responses. In addition, research presented covered multiple pathways behind alcohol-induced cellular dysfunction, including mitochondrial metabolism, cellular bioenergetics, gene regulation, and epigenetics. Finally, the work presented highlighted potential biomarkers and novel avenues of treatment for alcohol-induced organ damage.

Vasopressin Response and Clinical Trajectory in Septic Shock Patients.

BACKGROUND: In septic shock, vasopressors aim to improve tissue perfusion and prevent persistent organ dysfunction, a characteristic of chronic critical illness (CCI). Adjunctive vasopressin is often used to decrease catecholamine dosage, but the association of vasopressin response with subsequent patient outcomes is unclear. We hypothesized vasopressin response is associated with favorable clinical trajectory. METHODS: We included patients with septic shock receiving vasopressin as a catecholamine adjunct in this retrospective cohort study. We defined vasopressin response as a lowering of the catecholamine dose required to maintain mean arterial pressure ≥65 mm Hg, 6 h after vasopressin initiation. Clinical trajectories were adjudicated as early death (ED; death before day 14), CCI (ICU stay ≥14 days with persistent organ dysfunction), or rapid recovery (RR; not meeting ED or CCI criteria). Trajectories were placed on an ordinal scale with ED the worst outcome, CCI next, and RR the best outcome. The association of vasopressin response with clinical trajectory was assessed with multivariable ordinal logistic regression. RESULTS: In total 938 patients were included; 426 (45.4%) were vasopressin responders. The most frequent trajectory was ED (49.8%), 29.7% developed CCI, and 20.5% had rapid recovery. In survivors to ICU day 14 (those without ED), 59.2% had CCI and 40.8% experienced RR. Compared with vasopressin non-responders, vasopressin responders less frequently experienced ED (42.5% vs. 55.9%) and more frequently experienced RR (24.6% vs. 17.0%; P < 0.01). After controlling for confounders, vasopressin response was independently associated with higher odds of developing a better clinical trajectory (OR 1.63; 95% CI 1.26-2.10). Medical patients most frequently developed ED and survivors more commonly developed CCI than RR; surgical patients developed the three trajectories with similar frequency (P < 0.01). CONCLUSIONS: Vasopressin responsive status was associated with improved clinical trajectory in septic shock patients. Early vasopressin response is a potential novel prognostic marker for short-term clinical trajectory.

Pathophysiology and Management of Neurogenic Pulmonary Edema in Patients with Acute Severe Brain Injury.

Acute brain injury (ABI) consists of any acquired insult to the brain and is a significant cause of morbidity and mortality worldwide. Approximately 20% to 30% of patients with ABI develop a lung injury called neurogenic pulmonary edema (NPE), and its development often results in poor outcomes. This article provides a narrative review of the evidence regarding proposed mechanisms of injury, diagnosis, and treatment of NPE in the critical care setting. PubMed and Ovid databases were searched for observational or prospective studies relevant to the diagnosis and treatment of NPE. Overall, studies showed that although the specific mechanisms responsible for NPE remain uncertain, putative mechanisms include vaso- and venoconstriction, catecholamine release with resultant pulmonary vasoconstriction called the "blast injury theory," increased vagal tone, and increased capillary permeability. Diagnosis involves identifying signs of pulmonary edema in patients who experienced a neurologic insult. Management strategies aim to address both brain and lung injury, and treatment modalities appear to work best when balanced toward maintaining a normal physiologic state. In summary, NPE is an often underdiagnosed but important sequela of ABI, which may result in additional long-term morbidity. It is therefore an important entity for providers to recognize and tailor their clinical approach toward.

Sepsis, pyruvate, and mitochondria energy supply chain shortage.

Balancing high energy-consuming danger resistance and low energy supply of disease tolerance is a universal survival principle that often fails during sepsis. Our research supports the concept that sepsis phosphorylates and deactivates mitochondrial pyruvate dehydrogenase complex control over the tricarboxylic cycle and the electron transport chain. StimulatIng mitochondrial energetics in septic mice and human sepsis cell models can be achieved by inhibiting pyruvate dehydrogenase kinases with the pyruvate structural analog dichloroacetate. Stimulating the pyruvate dehydrogenase complex by dichloroacetate reverses a disruption in the tricarboxylic cycle that induces itaconate, a key mediator of the disease tolerance pathway. Dichloroacetate treatment increases mitochondrial respiration and ATP synthesis, decreases oxidant stress, overcomes metabolic paralysis, regenerates tissue, organ, and innate and adaptive immune cells, and doubles the survival rate in a murine model of sepsis.

Association of Arterial pH With Hemodynamic Response to Vasopressin in Patients With Septic Shock: An Observational Cohort Study.

OBJECTIVES: Vasopressin is reported to retain vasoconstrictive activity in the setting of acidemia, but preclinical models are inconsistent and studies have not evaluated the clinical effectiveness of vasopressin based on arterial pH. This study sought to determine the association between arterial pH and blood pressure after vasopressin initiation in septic shock. DESIGN: This retrospective, multicenter, observational cohort study evaluated the association of arterial pH at the time of vasopressin initiation with hemodynamic response to vasopressin and change in catecholamine dose after vasopressin initiation. Hemodynamic response was defined as a catecholamine dose decrease with mean arterial pressure greater than or equal to 65 mm Hg at 6 hours after vasopressin initiation. SETTING: Patients from eight hospitals in a health system were evaluated. PATIENTS: Patients with septic shock initiated on vasopressin as a catecholamine adjunct between January 2012 and November 2017 were screened for inclusion. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 1,350 patients were included. At the time of vasopressin initiation patients were severely ill with arterial pH 7.28 ± 0.13, Sequential Organ Failure Assessment 14.1 ± 3.5, lactate 5.6 ± 4.6 mmol/L, and norepinephrine-equivalent catecholamine dose 32.3 ± 25.4 µg/min. After adjusting for lactate and Sequential Organ Failure Assessment with multivariable logistic regression, lower arterial pH was independently associated with lower odds of hemodynamic response to vasopressin (for each 0.1 unit arterial pH was below 7.40, response odds ratio 0.79; 95% CI, 0.72-0.87). For each 0.1 unit the pH was below 7.40 at vasopressin initiation, the norepinephrine-equivalent catecholamine dose increased by 1.5 µg/min (95% CI, 0.5-2.5 µg/min) at 1 hour, and increased by 2.5 µg/min (95% CI, 1.4-3.5 µg/min) at 6 hours after vasopressin initiation. CONCLUSIONS: Compared with higher arterial pH, patients with septic shock and low arterial pH had lower odds of vasopressin response and higher catecholamine doses after vasopressin initiation. Similar to other vasopressors, the clinical effectiveness of vasopressin appears to be impaired in the setting of acidemia.

SIRT2-PFKP interaction dysregulates phagocytosis in macrophages with acute ethanol-exposure.

Alcohol abuse, reported by 1/8th critically ill patients, is an independent risk factor for death in sepsis. Sepsis kills over 270,000 patients/year in the US. We reported that the ethanol-exposure suppresses innate-immune response, pathogen clearance, and decreases survival in sepsis-mice via sirtuin 2 (SIRT2). SIRT2 is an NAD+-dependent histone-deacetylase with anti-inflammatory properties. We hypothesized that in ethanol-exposed macrophages, SIRT2 suppresses phagocytosis and pathogen clearance by regulating glycolysis. Immune cells use glycolysis to fuel increased metabolic and energy demand of phagocytosis. Using ethanol-exposed mouse bone marrow- and human blood monocyte-derived macrophages, we found that SIRT2 mutes glycolysis via deacetylating key glycolysis regulating enzyme phosphofructokinase-platelet isoform (PFKP), at mouse lysine 394 (mK394, human: hK395). Acetylation of PFKP at mK394 (hK395) is crucial for PFKP function as a glycolysis regulating enzyme. The PFKP also facilitates phosphorylation and activation of autophagy related protein 4B (Atg4B). Atg4B activates microtubule associated protein 1 light chain-3B (LC3). LC3 is a driver of a subset of phagocytosis, the LC3-associated phagocytosis (LAP), which is crucial for segregation and enhanced clearance of pathogens, in sepsis. We found that in ethanol-exposed cells, the SIRT2-PFKP interaction leads to decreased Atg4B-phosphorylation, decreased LC3 activation, repressed phagocytosis and LAP. Genetic deficiency or pharmacological inhibition of SIRT2 reverse PFKP-deacetylation, suppressed LC3-activation and phagocytosis including LAP, in ethanol-exposed macrophages to improve bacterial clearance and survival in ethanol with sepsis mice.

Hemodynamic Response to Vasopressin Dosage of 0.03 Units/Min vs. 0.04 Units/Min in Patients With Septic Shock.

BACKGROUND: Arginine vasopressin (AVP) is suggested as an adjunct to norepinephrine in patients with septic shock. Guidelines recommend an AVP dosage up to 0.03 units/min, but 0.04 units/min is commonly used in practice based on initial studies. This study was designed to compare the incidence of hemodynamic response between initial fixed-dosage AVP 0.03 units/min and AVP 0.04 units/min. METHODS: This retrospective, multi-hospital health system, cohort study included adult patients with septic shock receiving AVP as an adjunct to catecholamine vasopressors. Patients were excluded if they received an initial dosage other than 0.03 units/min or 0.04 units/min, or AVP was titrated within the first 6 hours of therapy. The primary outcome was hemodynamic response, defined as a mean arterial pressure ≥65 mm Hg and a decrease in catecholamine dosage at 6 hours after AVP initiation. Inverse probability of treatment weighting (IPTW) based on the propensity score for initial AVP dosage receipt was utilized to estimate adjusted exposure effects. RESULTS: Of the 1536 patients included in the observed data, there was a nearly even split between initial AVP dosage of 0.03 units/min (n = 842 [54.8%]) and 0.04 units/min (n = 694 [45.2%]). Observed patients receiving AVP 0.03 units/min were more frequently treated at the main campus academic medical center (96.3% vs. 52.2%, p < 0.01) and in a medical intensive care unit (87.4% vs. 39.8%, p < 0.01). The IPTW analysis included 1379 patients with achievement of baseline covariate balance. There was no evidence for a difference between groups in the incidence of hemodynamic response (0.03 units/min 50.0% vs. 0.04 units/min 53.1%, adjusted relative risk 1.06 [95% CI 0.94, 1.20]). CONCLUSIONS: Initial AVP dosing varied by hospital and unit type. Although commonly used, an initial AVP dosage of 0.04 units/min was not associated with a higher incidence of early hemodynamic response to AVP in patients with septic shock.

A High Neutrophil-Lymphocyte Ratio Is Associated With Increased Morbidity and Mortality in Patients With Coronavirus Disease 2019.

OBJECTIVES: The neutrophil-lymphocyte ratio is an inexpensive and simple inflammatory marker. A higher ratio, indicative of an acute hyperinflammatory response or diminished overall physiologic health status, has been associated with poor prognoses. This study aimed to evaluate the prognostic potential of admission neutrophil-lymphocyte ratio in patients admitted to the medical ICU with coronavirus disease 2019. DESIGN: Retrospective review of prospectively collected data. SETTING: Medical ICU from a large medical center. PATIENTS: 2,071 consecutive patients admitted to the medical ICU with laboratory-confirmed severe acute respiratory syndrome coronavirus-2 between March 15, 2020, and December 30, 2020, were grouped by neutrophil-lymphocyte ratio above or below the median (7.45) at the time of hospital admission. INTERVENTIONS: Complete blood count with differential at the time of hospital admission. MEASUREMENTS AND MAIN RESULTS: A neutrophil-lymphocyte ratio above 7.45 at the time of hospital admission was associated with increased need for mechanical ventilation (45.8% vs 38.0%, p < 0.0001), vasopressor therapy (55.6% vs 48.2%, p = 0.001), and decreased survival through 180 days (54.8% vs 67.0%, p < 0.0001). Patients with a high neutrophil-lymphocyte ratio exhibited a 1.32 (95% CI, 1.14-1.54) times greater risk of mortality than those with a low neutrophil-lymphocyte ratio. CONCLUSIONS: The neutrophil-lymphocyte ratio at the time of hospital admission is an independent risk factor for morbidity and mortality. This prognostic indicator may assist clinicians appropriately identify patients at heightened risk for a severe disease course and tailor treatment accordingly.

Sirtuin 2 Dysregulates Autophagy in High-Fat-Exposed Immune-Tolerant Macrophages.

Obesity increases morbidity and resource utilization in sepsis patients. The immune response in sepsis transitions from an endotoxin-responsive hyper- to an endotoxin-tolerant hypo-inflammatory phase. The majority of sepsis mortality occurs during hypo-inflammation. We reported prolonged hypo-inflammation with increased sirtuin 2 (SIRT2) expression in obese-septic mice. The effect of direct exposure to high-fat/free fatty acid (FFA) and the role of SIRT2 in immune cells during the transition to hypo-inflammation is not well-understood. Autophagy, a degradation process of damaged protein/organelles, is dysregulated during sepsis. Here, we investigated the effect of direct FFA exposure and the role of SIRT2 expression on autophagy as macrophages transition from hyper-to hypo-inflammation. We found, FFA-exposed RAW 264.7 cells with lipopolysaccharide (LPS) stimulation undergo endotoxin-sensitive ("sensitive") hyper- followed by endotoxin tolerant ("tolerant") hypo-inflammatory phases; SIRT2 expression increases significantly in tolerant cells. Autophagy proteins LC3b-II, and beclin-1 increase in FFA-sensitive and decrease in tolerant cells; p62 expressions continue to accumulate in tolerant cells. We observed that SIRT2 directly deacetylates α-tubulin and impairs autophagy clearance. Importantly, we find SIRT2 inhibitor AK-7 treatment during endotoxin tolerant phase reverses autophagy dysregulation with improved autophagy clearance in FFA-tolerant cells. Thus, we report impaired autophagosome formation and autophagy clearance via increased SIRT2 expression in FFA-exposed tolerant macrophages.

Tocilizumab in Coronavirus Disease 2019-Related Critical Illness: A Propensity Matched Analysis.

The primary objective was to evaluate ICU mortality at 28 days in patients with severe hypoxemic respiratory failure due to coronavirus disease 2019 infection who received tocilizumab. The secondary objectives were to evaluate ICU-, hospital-, mechanical ventilation-, and vasopressor-free days at day 28 and development of secondary infections. DESIGN: Retrospective, observational, multicenter, cohort study between March 15, 2020, and May 31, 2020. Using propensity score matching based on ICU admission source, C-reactive protein, Sequential Organ Failure Assessment score, vasopressor use, age, race, weight, and mechanical ventilation, patients who received tocilizumab were matched to patients who did not receive tocilizumab. SETTING: Ten hospitals within the Cleveland Clinic Enterprise. PATIENTS: Adult patients admitted to a medical, surgical, neurosciences, or mixed ICU with severe acute respiratory syndrome coronavirus 2 infection. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Four-hundred forty-four patients were included: 342 patients (77%) did not receive tocilizumab and 102 patients (23%) received tocilizumab. Of those, 82 patients in each arm were matched. Before matching, patients who received tocilizumab had higher Sequential Organ Failure Assessment scores (6.1 ± 3.4 vs 4.7 ± 3.6), higher C-reactive protein (21.0 ± 10.2 vs 13.7 ± 9.6 mg/dL), higher frequency of intubation, vasopressor requirement, and paralytics. After matching, characteristics were more balanced and over 85% of patients required mechanical ventilation. ICU mortality was lower in tocilizumab group (23.2% vs 37.8%; risk difference, -15%; 95% CI, -29% to -1%), with more ICU-, hospital-, and vasoactive-free days at day 28 compared with those who did not receive tocilizumab. There was no difference in mechanical ventilation-free days at day 28 or development of secondary infections. CONCLUSIONS: Tocilizumab use was associated with a significant decrease in ICU mortality in critically ill coronavirus disease 2019 patients with severe hypoxemic respiratory failure. Future randomized controlled trials limited to tocilizumab administration in critically ill coronavirus disease 2019 patients, with severe hypoxemic respiratory failure, are needed to support these findings.

Ethanol Exposure Attenuates Immune Response in Sepsis via Sirtuin 2 Expression.

BACKGROUND: Sepsis and septic shock kill over 270,000 patients per year in the United States. Sepsis transitions from a hyper-inflammatory to a hypo-inflammatory phase. Alcohol dependence is a risk factor for mortality from sepsis. Ethanol (EtOH) exposure impairs pathogen clearance through mechanisms that are not fully understood. Sirtuin 2 (SIRT2) interferes with pathogen clearance in immune cells but its role in the effects of EtOH on sepsis is unknown. We studied the effect of EtOH exposure on hyper- and hypo-inflammation and the role of SIRT2 in mice. METHODS: We exposed C57Bl/6 (WT) mice to EtOH via drinking water and used intraperitoneal cecal slurry (CS)-induced sepsis to study: (i) 7-day survival, (ii) leukocyte adhesion (LA) in the mesenteric microcirculation during hyper- and hypo-inflammation, (iii) peritoneal cavity bacterial clearance, and (iv) SIRT2 expression in peritoneal macrophages. Using EtOH-exposed and lipopolysaccharide (LPS)-stimulated RAW 264.7 (RAW) cell macrophages for 4 hours or 24 hours, we studied: (i) tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), and SIRT2 expression, and (ii) the effect of the SIRT2 inhibitor AK-7 on inflammatory response at 24 hours. Lastly, we studied the effect of EtOH on sepsis in whole body Sirt2 knockout (SIRT2KO) mice during hyper- and hypo-inflammation, bacterial clearance, and 7-day survival. RESULTS: WT EtOH-sepsis mice showed: (i) Decreased survival, (ii) Muted LA in the microcirculation, (iii) Lower plasma TNF-α and IL-6 expression, (iv) Decreased bacterial clearance, and (v) Increased SIRT2 expression in peritoneal macrophages versus vehicle-sepsis. EtOH-exposed LPS-stimulated RAW cells showed: (i) Muted TNF-α, IL-6, and increased IL-10 expression at 4 hours, (ii) endotoxin tolerance at 24 hours, and (iii) reversal of endotoxin tolerance with the SIRT2 inhibitor AK-7. EtOH-exposed SIRT2KO-sepsis mice showed greater 7-day survival, LA, and bacterial clearance than WT EtOH-sepsis mice. CONCLUSION: EtOH exposure decreases survival and reduces the inflammatory response to sepsis via increased SIRT2 expression. SIRT2 is a potential therapeutic target in EtOH with sepsis.