Neutrophil macroaggregates promote widespread pulmonary thrombosis after gut ischemia

Area of Science:

• Cardiovascular Biology
• Pulmonary Medicine
• Critical Care Medicine

Background:

• Gut ischemia is a frequent complication in critically ill patients, often leading to thrombosis and inflammation in remote organs.
• The precise mechanisms connecting gut hemodynamic changes to distant organ thrombosis are not well understood.
• Existing research highlights the need to clarify the link between gut injury and systemic thrombotic events.

Purpose of the Study:

• To investigate the mechanisms by which gut ischemia induces thrombosis in distant organs.
• To identify the cellular players and pathways involved in this process.
• To explore potential therapeutic targets for preventing ischemia-induced thrombosis.

Main Methods:

• Utilized a mouse model of gut ischemia-reperfusion injury.
• Employed intravital microscopy to observe neutrophil behavior during injury.
• Investigated the role of platelets and neutrophil macroaggregates in pulmonary thrombosis.
• Examined human samples from patients with acute respiratory distress syndrome.

Main Results:

• Gut ischemia triggered a unique pulmonary thrombotic disorder characterized by neutrophil macroaggregates.
• These aggregates caused widespread occlusion of pulmonary vasculature.
• Neutrophils extracted membrane fragments from dying platelets, facilitating macroaggregation.
• Similar pulmonary thrombotic responses were observed in human acute respiratory distress syndrome (ARDS) patients.
• Targeting platelet cyclophilin D prevented neutrophil macroaggregation and pulmonary thrombosis.

Conclusions:

• Gut ischemia induces a distinct pulmonary thrombotic disorder mediated by neutrophil macroaggregates.
• Dying platelets play a crucial role in facilitating neutrophil aggregation and subsequent thrombosis.
• Therapeutic strategies targeting platelet death pathways show promise for mitigating pulmonary thrombosis in critically ill patients.