Mechanical ventilation induces neutrophil extracellular trap formation

Area of Science:

• Pulmonary Medicine
• Immunology
• Critical Care

Background:

• Mechanical ventilation can cause lung injury (VILI), characterized by inflammation and neutrophil infiltration.
• Neutrophils release neutrophil extracellular traps (NETs), which are DNA and protein structures implicated in inflammation.
• This study investigated the role of NETs in a VILI mouse model.

Purpose of the Study:

• To determine if NETs are produced during ventilator-induced lung injury (VILI).
• To assess the contribution of NETs to lung injury in a VILI model.
• To evaluate the therapeutic potential of targeting NETs in VILI.

Main Methods:

• A two-hit lipopolysaccharide/VILI mouse model was used.
• Mice were treated with intratracheal deoxyribonuclease (DNase) or blockers of NET formation.
• Lung compliance, bronchoalveolar lavage fluid protein, NET markers (citrullinated histone-3, DNA), and inflammatory markers were assessed.

Main Results:

• High tidal volume mechanical ventilation induced NET markers in lipopolysaccharide-treated mice.
• Intratracheal DNase treatment reduced NET markers and attenuated the loss of lung static compliance.
• Blockade of HMGB1 or IL-1β did not prevent NETosis or protect against VILI.

Conclusions:

• NETosis is induced during VILI, and DNase treatment effectively eliminates NETs.
• Despite NET induction and reduction by DNase, NETs do not appear to play a major pathogenic role in this VILI model.
• The findings contrast with previous studies on transfusion-related acute lung injury, highlighting model-specific differences in NET involvement.