Search

Competing Interests: Dr. Balk received funding from Dompe Pharmaceuticals, Merck, and BioMerieux. Dr. Sarwal’s institution receives funding from Biogen, Bard, Novartis, CVR Global, Lung Pacer, the National Institute on Aging (R01 AG066910-01), Shaltout, and Butterfly. Dr. Gershengorn disclosed that she served as an advisory board member for Gilead Sciences. Dr. Menon received funding from the Canadian Institutes of Health Research. Dr. Jayaprakash disclosed that she was the site principle investigator for sponsored trials through Abott Laboratories and BioCogniV. Dr. Russell reports patents owned by the University of British Columbia (UBC) that are related to the use of PCSK9 inhibitor(s) in sepsis and related to the use of vasopressin in septic shock and a patent owned by Ferring for use of selepressin in septic shock. Dr. Russell is an inventor on these patents. Dr. Russell was a founder, Director and shareholder in Cyon Therapeutics and is a shareholder in Molecular You Corp. Dr. Russell is no longer actively consulting for any industry. Dr. Russell reports receiving consulting fees in the last 3 years from: 1) SIB Therapeutics LLC (developing a sepsis drug). 2) Ferring Pharmaceuticals (manufactures vasopressin and developing selepressin). 3) Dr. Russell was a funded member of the Data and Safety Monitoring Board of an NIH-sponsored trial of plasma in COVID-19 (PASS-IT-ON) (2020–2021). 4) PAR Pharma (sells prepared bags of vasopressin). Dr. Russell reports having received an investigator-initiated grant from Grifols (entitled “Is HBP a mechanism of albumin’s efficacy in human septic shock?”) that was provided to and administered by UBC. Dr. Russell was a nonfunded Science Advisor and member, Government of Canada COVID-19 Therapeutics Task Force (June 2020 to 2021). Dr. Asehnoune received funding from LFB and Edwards Lifecience Baxter. Dr. Spencer-Segal received funding from Camurus AB, Chiasma, and Recordati Rare Diseases. Dr. Esper received funding from Honeywell. The remaining authors have disclosed that they do not have any potential conflicts of interest.

Pseudomonas aeruginosa (PA) remains one of the leading causes of nosocomial acute pneumonia. The array of virulence factors expressed by PA and the intense immune response associated with PA pneumonia play a major role in the severity of these infections. New therapeutic approaches are needed to overcome the high resistance of PA to antibiotics and to reduce the direct damage to host tissues. Through its immunomodulatory and anti-virulence effects, azithromycin (AZM) has demonstrated clinical benefits in patients with chronic PA respiratory infections. However, there is relatively little evidence in PA acute pneumonia. We investigated the effects of AZM, as an adjunctive therapy combined with ceftazidime (CAZ), in a murine model of PA acute pneumonia. We observed that the combined therapy (i) reduces the weight loss of mice 24 h post-infection (hpi), (ii) decreases neutrophil influx into the lungs at 6 and 24 hpi, while this effect is absent in a LPS-induced pneumonia or when PA is pretreated with antibiotics and mice do not receive any antibiotics, and that (iii) AZM, alone or with CAZ, modulates the expression of PA quorum sensing regulators and virulence factors (LasI, LasA, PqsE, PhzM, ExoS). Our findings support beneficial effects of AZM with CAZ on PA acute pneumonia by both bacterial virulence and immune response modulations. Further investigations are needed to clarify the exact underlying mechanisms responsible for the reduction of the neutrophils influx and to better discriminate between direct immunomodulatory properties of AZM, and indirect effects on neutrophilia resulting from bacterial virulence modulation., (© 2023 The Societies and John Wiley & Sons Australia, Ltd.)

Background: Interleukin (IL)-22 is a cytokine involved in tissue protection and repair following lung pathologies. Interferon (IFN)-λ cytokines displayed similar properties during viral infection and a synergy of action between these two players has been documented in the intestine. We hypothesize that during Pseudomonas aeruginosa challenge, IL-22 up-regulates IFN-λ and that IFN-λ exhibits protective functions during Pseudomonas aeruginosa acute pneumonia model in mice., Methods: Using an in vitro human alveolar epithelial cell line A549, we assessed the ability of IL-22 to enhance IFN-λ expression during infection. IFN-λ protective function was evaluated in an acute mouse pneumonia model., Results: We first demonstrated in murine lungs that only type-II alveolar cells express IL-22 receptor and that IL-22 treatment of A549 cell line up-regulates IFN-λ expression. In a murine acute pneumonia model, IL-22 administration maintained significant IFN-λ levels in the broncho-alveolar fluids whereas IL-22 neutralization abolished IFN-λ up-regulation. In vivo administration of IFN-λ during Pseudomonas aeruginosa pneumonia improves mice outcome by dampening neutrophil recruitment and decreasing epithelium damages., Discussion: We show here that IL-22 regulates IFN-λ levels during Pseudomonas aeruginosa pneumonia., (Copyright © 2019. Published by Elsevier Ltd.)

Background: To propose a combination of blood biomarkers for the prediction of hospital-acquired pneumonia (HAP) and for the selection of traumatic brain-injured (TBI) patients eligible for corticosteroid therapy for the prevention of HAP., Methods: This was a sub-study of the CORTI-TC trial, a multicenter, randomized, double-blind, controlled trial evaluating the risk of HAP at day 28 in 336 TBI patients treated or not with corticosteroid therapy. Patients were between 15 and 65 years with severe traumatic brain injury (Glasgow coma scale score ≤ 8 and trauma-associated lesion on brain CT scan) and were enrolled within 24 h of trauma. The blood levels of CRP and cortisol total&free, as a surrogate marker of the pro/anti-inflammatory response balance, were measured in samples collected before the treatment initiation. Endpoint was HAP on day 28., Results: Of the 179 patients with available samples, 89 (49.7%) developed an HAP. Cortisol total&free and CRP blood levels upon ICU admission were not significantly different between patients with or without HAP. The cortisol total /CRP ratio upon admission was 2.30 [1.25-3.91] in patients without HAP and 3.36 [1.74-5.09] in patients with HAP (p = 0.021). In multivariate analysis, a cortisol total /CRP ratio > 3, selected upon the best Youden index on the ROC curve, was independently associated with HAP (OR 2.50, CI95% [1.34-4.64] p = 0.004). The HR for HAP with corticosteroid treatment was 0.59 (CI95% [0.34-1.00], p = 0.005) in patients with a cortisol total /CRP ratio > 3, and 0.89 (CI95% [0.49-1.64], p = 0.85) in patients with a ratio < 3., Conclusion: A cortisol total /CRP ratio > 3 upon admission may predict the development of HAP in severe TBI. Among these patients, corticosteroids reduce the occurrence HAP. We suggest that this ratio may select the patients who may benefit from corticosteroid therapy for the prevention of HAP.

Dendritic cells (DCs) are bone marrow derived cells which continuously seed in peripheral tissue. During infection, DCs play an essential interface between innate and adaptive immunity. Pneumonia is a lung inflammation triggered by pathogens and is characterized by excessive release of inflammatory cytokines that activate innate and acquired immunity. Pneumonia induces a rapid and protracted state of susceptibility to secondary infection, a state so-called sepsis-induced immunosuppression. In this review, we focus on the role of DCs in the development of this state of immunosuppression. Early during inflammation, activated DCs are characterized by decreased capacity of antigen (cross)- presentation of newly encountered antigens and decreased production of immunogenic cytokines, and sepsis-induced immunosuppression is mainly explained by a depletion of immature DCs which had all become mature. At a later stage, newly formed respiratory immature DCs are locally programmed by an immunological scare left-over by inflammation to induce tolerance. Tolerogenic Blimp1+ DCs produce suppressive cytokines such as tumor growth factor-B and participate to the maintenance of a local tolerogenic environment notably characterized by accumulation of Treg cells. In mice, the restoration of the immunogenic functions of DCs restores the mucosal immune response to pathogens. In humans, the modulation of inflammation by glucocorticoid during sepsis or trauma preserves DC immunogenic functions and is associated with resistance to secondary pneumonia. Finally, we propose that the alterations of DCs during and after inflammation can be used as biomarkers of susceptibility to secondary pneumonia and are promising therapeutic targets to enhance outcomes of patients with secondary pneumonia.

Lung infections cause prolonged immune alterations and elevated susceptibility to secondary pneumonia. We found that, after resolution of primary viral or bacterial pneumonia, dendritic cells (DC), and macrophages exhibited poor antigen-presentation capacity and secretion of immunogenic cytokines. Development of these "paralyzed" DCs and macrophages depended on the immunosuppressive microenvironment established upon resolution of primary infection, which involved regulatory T (Treg) cells and the cytokine TGF-β. Paralyzed DCs secreted TGF-β and induced local Treg cell accumulation. They also expressed lower amounts of IRF4, a transcription factor associated with increased antigen-presentation capacity, and higher amounts of Blimp1, a transcription factor associated with tolerogenic functions, than DCs present during primary infection. Blimp1 expression in DC of humans suffering sepsis or trauma correlated with severity and complicated outcomes. Our findings describe mechanisms underlying sepsis- and trauma-induced immunosuppression, reveal prognostic markers of susceptibility to secondary infections and identify potential targets for therapeutic intervention., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: Respiratory complications constitute an important determinant of length of stay in tetraplegic patients. In a population of tetraplegic patients, we investigated the factors involved in the duration of mechanical ventilation (MV) and whether the duration of MV was associated with the long-term neurologic status., Material and Methods: In a retrospective study in 3 intensive care units (ICUs) (January 2001 to December 2009), consecutive patients (≥ 18 years) hospitalized for acute (≤ 24 hours) traumatic tetraplegia were included in the study. Patients with severe brain injury or who died in the first 48 hours were excluded. The primary outcome was the duration of MV. The secondary outcomes were the American Spinal Injury Association (ASIA) motor score on ICU discharge and at 1 year., Results: A total of 164 consecutive adult patients with tetraplegia were analyzed. Median (interquartile range) ASIA motor scores were 15 (6-26) on admission, 22 (9-40) on ICU discharge (n = 145 survivors), and 37 (10-80) at 1 year (n = 52 complete follow-up). The median duration of MV was 11 (2-26) days. In multivariate analysis, MV duration increased with pneumonia (P < .0001), atelectasis (P = .0042), and tracheotomy (P < .0001). In exploratory analysis, an increased duration of MV was the only factor associated in multivariate analysis with a low ASIA motor score on ICU discharge (P = .0201) and at 1 year (P = .0003)., Conclusions: Prevention of pneumonia and atelectasis is critical for the reduction of MV in tetraplegic patients. Prolonged MV was independently associated with poor neurologic status., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Haemorrhage-induced immunosuppression has been linked to nosocomial infections. We assessed the impact of monophosphoryl lipid A, a Toll/interleukin-1 receptor-domain-containing adaptor protein inducing interferon-biased Toll-like receptor-4 agonist currently used as a vaccine adjuvant in humans, on post-haemorrhage susceptibility to infection. We used a mouse model of post-haemorrhage pneumonia induced by methicillin-susceptible Staphylococcus aureus. Monophosphoryl lipid A was administered intravenously after haemorrhage and before pneumonia onset. Haemorrhage altered survival rate, increased lung damage (neutrophil accumulation, oedema and cytokine release) and altered the functions of dendritic and natural killer cells. Here, we show that monophosphoryl lipid A decreased systemic dissemination of S. aureus and dampened inflammatory lung lesions. Monophosphoryl lipid A partially restored the capacity for antigen presentation and the transcriptional activity in dendritic cells. Monophosphoryl lipid A did not restore the interferon-γ mRNA but prevented interleukin-10 mRNA overexpression in natural killer cells compared with untreated mice. Ex vivo monophosphoryl lipid A-stimulated dendritic cells or natural killer cells harvested from haemorrhaged animals were adoptively transferred into mice undergoing post-haemorrhage pneumonia. Stimulated dendritic cells (but not stimulated natural killer cells) improved the survival rate compared with mice left untreated. In vivo depletion of natural killer cells decreased survival rate of monophosphoryl lipid A-treated mice. Dendritic and natural killer cells are critically involved in the beneficial effects of monophosphoryl lipid A within post-haemorrhage pneumonia.

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen commonly associated with lung and wound infections. Hypoxia is a frequent feature of the microenvironment of infected tissues which induces the expression of genes associated with innate immunity and inflammation in host cells primarily through the activation of the hypoxia-inducible factor (HIF) and Nuclear factor kappaB (NF-κB) pathways which are regulated by oxygen-dependent prolyl-hydroxylases. Hypoxia also affects virulence and antibiotic resistance in bacterial pathogens. However, less is known about the impact of hypoxia on host-pathogen interactions such as bacterial adhesion and infection. In the current study, we demonstrate that hypoxia decreases the internalization of P. aeruginosa into cultured epithelial cells resulting in decreased host cell death. This response can also be elicited by the hydroxylase inhibitor Dimethyloxallyl Glycine (DMOG). Reducing HIF-2α expression or Rho kinase activity diminished the effects of hypoxia on P. aeruginosa infection. Furthermore, in an in vivo pneumonia infection model, application of DMOG 48 h before infection with P. aeruginosa significantly reduced mortality. Thus, hypoxia reduces P. aeruginosa internalization into epithelial cells and pharmacologic manipulation of the host pathways involved may represent new therapeutic targets in the treatment of P. aeruginosa infection.

Context: The role of stress-dose hydrocortisone in the management of trauma patients is currently unknown., Objective: To test the efficacy of hydrocortisone therapy in trauma patients., Design, Setting, and Patients: Multicenter, randomized, double-blind, placebo-controlled HYPOLYTE (Hydrocortisone Polytraumatise) study. From November 2006 to August 2009, 150 patients with severe trauma were included in 7 intensive care units in France., Intervention: Patients were randomly assigned to a continuous intravenous infusion of either hydrocortisone (200 mg/d for 5 days, followed by 100 mg on day 6 and 50 mg on day 7) or placebo. The treatment was stopped if patients had an appropriate adrenal response., Main Outcome Measure: Hospital-acquired pneumonia within 28 days. Secondary outcomes included the duration of mechanical ventilation, hyponatremia, and death., Results: One patient withdrew consent. An intention-to-treat (ITT) analysis included the 149 patients, a modified ITT analysis included 113 patients with corticosteroid insufficiency. In the ITT analysis, 26 of 73 patients (35.6%) treated with hydrocortisone and 39 of 76 patients (51.3%) receiving placebo developed hospital-acquired pneumonia by day 28 (hazard ratio [HR], 0.51; 95% confidence interval [CI], 0.30-0.83; P = .007). In the modified ITT analysis, 20 of 56 patients (35.7%) in the hydrocortisone group and 31 of 57 patients (54.4%) in the placebo group developed hospital-acquired pneumonia by day 28 (HR, 0.47; 95% CI, 0.25-0.86; P = .01). Mechanical ventilation-free days increased with hydrocortisone by 4 days (95% CI, 2-7; P = .001) in the ITT analysis and 6 days (95% CI, 2-11; P < .001) in the modified ITT analysis. Hyponatremia was observed in 7 of 76 (9.2%) in the placebo group vs none in the hydrocortisone group (absolute difference, -9%; 95% CI, -16% to -3%; P = .01). Four of 76 patients (5.3%) in the placebo group and 6 of 73 (8.2%) in the hydrocortisone group died (absolute difference, 3%; 95% CI, -5% to 11%; P = .44)., Conclusion: In intubated trauma patients, the use of an intravenous stress-dose of hydrocortisone, compared with placebo, resulted in a decreased risk of hospital-acquired pneumonia., Trial Registration: clinicaltrials.gov Identifier: NCT00563303.

Ventilator-acquired pneumonia (VAP) is a common burden in intensive care unit (ICU) patients, but, to date, specific data are not available in patients with severe aneurysmal subarachnoid hemorrhage (SAH). A single neuro-ICU retrospective analysis of 193 patients with SAH requiring mechanical ventilation (MV) ≥48 h admitted from January 2005 to May 2010 was undertaken. The diagnosis of early VAP was prospectively upheld during a multidisciplinary staff meeting, according to the American Thoracic Society (ATS) 2005 guidelines with a threshold of 7 days after the onset of MV. Patients had a median age of 53 (44-62) years and 70 (36 %) were male. The median Glasgow coma scale (GCS) score before MV was 9 (5-14). 142 (74 %) patients had a World Federation of Neurosurgeons (WFNS) score ≥III. Aneurysm was secured with an endovascular coiling procedure in 162 (84 %) patients. 81 (48.7 %) patients declared an early VAP. On multivariate analysis, male sex (odds ratio [OR] 2.26, 95 % confidence interval [CI] [1.14-4.46]), use of mannitol before day 7 (OR 3.03, 95 % CI [1.54-5.95]), and achieving enteral nutrition ≥20 kcal kg day after day 7 (OR 2.91, 95 % CI [1.27-6.67]) remained independent risk factors of VAP. The main pathogens involved were methicillin-susceptible Staphylococcus aureus (MSSA) (34.9 %), Haemophilus influenzae (28.1 %), Streptococcus pneumoniae (15.5 %), and Enterobacteriaceae (10.7 %). Early VAP was associated with a longer duration of MV and ICU stay, but not with an excess of mortality. Early VAP bears significant morbidity in patients with severe SAH. Pathogens involved in early VAP are susceptible to antibiotics. Among modifiable risk factors of VAP, early enteral nutrition could be an easy and effective target. [ABSTRACT FROM AUTHOR]

Abstract Background Traumatic brain injury (TBI) is a main cause of severe prolonged disability of young patients. Hospital acquired pneumonia (HAP) add to the morbidity and mortality of traumatic brain-injured patients. In one study, hydrocortisone for treatment of traumatic-induced corticosteroid insufficiency (CI) in multiple injured patients has prevented HAP, particularly in the sub-group of patients with severe TBI. Fludrocortisone is recommended in severe brain-injured patients suffering from acute subarachnoid hemorrhage. Whether an association of hydrocortisone with fludrocortisone protects from HAP and improves neurological recovery is uncertain. The aim of the current study is to compare corticotherapy to placebo for TBI patients with CI. Methods The CORTI-TC (Corticotherapy in traumatic brain-injured patients) trial is a multicenter, randomized, placebo controlled, double-blind, two-arms study. Three hundred and seventy six patients hospitalized in Intensive Care Unit with a severe traumatic brain injury (Glasgow Coma Scale ≤ 8) are randomized in the first 24 hours following trauma to hydrocortisone (200 mg.day-1 for 7 days, 100 mg on days 8-9 and 50 mg on day-10) with fludrocortisone (50 μg for 10 days) or double placebo. The treatment is stopped if patients have an appropriate adrenal response. The primary endpoint is HAP on day-28. The endpoint of the ancillary study is the neurological status on 6 and 12 months. Discussion The CORTI-TC trial is the first randomized controlled trial powered to investigate whether hydrocortisone with fludrocortisone in TBI patients with CI prevent HAP and improve long term recovery. Trial registration NCT01093261

Abstract: Infections are a major cause of death and morbidity after acute injury of the central nervous system (CNS). Acute lesions of the CNS alter immune homeostasis contributing to the development of immunosuppression (IS), and making the bed of the infection. IS results in a decreased phagocytic functions of neutrophils and macrophages as well as monocyte deactivation (decreased capacity of antigen presentation to lymphocytes). The immune abnormalities occur very quickly and may last for weeks. The neurovegetative system is closely connected to the secondary lymphoid organs where cells of innate immunity receive information from injured organs inducing the long lasting adaptive immune response (immune synapse). The sympathetic system is critically involved in the IS through production of anti-inflammatory mediators like interleukin-10. This may prove important as all types of acute injury of the CNS can lead to direct damage to sympathetic centers. Specialized units of care for ischemic stroke, taking into account the risk of infection related to the IS, have improved the prognosis until 18th month after the initial damage of the SNC. It is now well recognized that the improved long-term prognosis is related with the secondary prevention of recurrent ischaemia as well as aggressive management of pulmonary infections. A better understanding of the pathophysiology of IS can be considered in the near future, opening the door to immunomodulatory therapeutic trials. [Copyright &y& Elsevier]