Study of the Effects of Bronchoalveolar Lavage Liquid in the ARDS on the Functioning of the Neutrophil Polynuclear System

Study Overview
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Brief Summary
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Firstly, the study assesses the effect of bronchoalveolar lavage fluid (BAL) from patients in (acute respiratory distress syndrome (ARDS) on the life span of PNNs and on the phagocytosis of apoptotic cells by macrophages and polynuclear neutrophil (PNN). Then, the effect of an antibody directed against high-mobility group box 1 protein (HMGB1) and the effect of metformin on efferocytosis are studied.

Detailed Description
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ARDS (acute respiratory distress syndrome) is a syndrome that causes significant mortality and morbidity. This syndrome is characterized by an alveolitis with polynuclear neutrophil (PNN). PNNs play an important role in the persistence and in injuries induced by ARDS. Several animal studies have shown that lesional edema can be increased by two important mechanisms: the increase in the lifespan of PNNs in the lung and the decrease in the phagocytosis capacities of apoptotic cells (efferocytosis) by macrophages and PNNs. However, confirmation of these data in humans does not exist, and knowledge of the mechanisms that may increase lung damage during ARDS will limit it and thus reduce the mechanical ventilation time of these patients as well as the mortality associated with ARDS.  high-mobility group box 1  (HMGB1) protein may be involved in reducing efferocytosis capacity. Similarly, activation of AMP-activated protein kinase (AMPk) could restore the clearance capacity of apoptotic cells in macrophages and PNNs.

Official Title
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Study of the Effects of Bronchoalveolar Lavage Liquid in the ARDS on the Functioning of the Neutrophil Polynuclear System

Conditions
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ARDS, Human

Intervention / Treatment
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* Procedure: Bronchoalveolar lavage


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ARDS Group : Inpatients hospitalized in medical intensive care with an ARDS defined according to the Berlin criteria and requiring an BAL(for diagnostic purpose in suspicion of pneumopathy acquired under mechanical ventilation). Control group : The control population is made up with patients with a BAL considered normal (endoscopy patients from the pneumology department). The normality of the BAL is defined by a normocellular wash with cellularity: < 150,000 to 200,000 cells/mL Cell composition (formula): macrophages: 80-90%, lymphocytes 5 to 10% (< 20%), neutrophils: < 5%, eosinophils: < 2%. Exclusion Criteria: Age < 18 years; Pregnant women ; Persons deprived of their liberty by judicial or administrative decision; Persons legally incapable; Persons not affiliated to a social security system; Previously immunocompromised patients (HIV infection, hematopathy, organ transplantation, immunosuppression); Patients who do not require a lung sample.

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| ARDS group<br>Inpatients hospitalized in medical intensive care with a table of ARDS defined according to the Berlin criteria and requiring an BAL for a diagnostic purpose under a suspicion of pneumopathy acquired under mechanical ventilation. | Procedure: Bronchoalveolar lavage<br> <br> |
| Control group<br>The control group will be made up of patients with an BAL considered normal (endoscopy patients from the pneumology department). The normality of the BAL is defined by a normocellular wash with cellularity: < 150,000 to 200,000 cells/mL Cell composition (formula): macrophages: 80-90%, lymphocytes 5 to 10% (< 20%), neutrophils: < 5%, eosinophils: < 2%. | Procedure: Bronchoalveolar lavage<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Lifespan of the PNNs | The lifespan of the PNNs is an indicator of apoptosis : two groups are compared with and without incubation in BAL fluid. Neutrophil necrosis was assessed by flow cytometry using a phycoerythrin-conjugated active caspase-3 apoptosis kit (Becton Dickinson, USA) | 24 hours after BAL | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| PNNs phagocytic index | This index relates the ability of the PNNs to produce neutrophil extracellular traps (NETs). The release of NETs was quantified by measuring fluorescence with a microplate fluorescence reader (Varioskan, ThermoFisher Scientific, USA). | 24 hours after BAL | 
| Efferocytosis index | The efferocytosis index was determined on 300 cells as the percentage of Human monocyte-derived macrophages (HMDMs) containing at least one ingested apoptotic neutrophil. | 24 hours after BAL | 
| Increase of PNNs phagocytic index with HMGB1 activator | PNNs phagocytic index is measured after incubation with an anti-HMGB1 neutralising antibody | 24 hours after BAL | 
| Increase of Efferocytosis index metformin | efferocytosis index was determined after incubation with an AMP-activated protein kinase (AMPK) activator (metformin) | 24 hours after BAL | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Bronchoalveolar lavage