Sepsis blocks the lungs through a platelet-immune cascade
Sepsis is one of the deadliest complications of severe infection, especially in older adults. A new study filmed what happens inside the lungs during sepsis in real time, and the main culprit turns out to be a joint operation between two normally separate cell types.
In sepsis, the body’s response to infection becomes so intense that it damages its own tissues. The lungs are especially vulnerable. The researchers, publishing in Science, used live imaging of lung blood vessels in mice during a sepsis reaction. What they observed was a coordinated cascade between neutrophils and platelets.
Neutrophils are white blood cells that respond first to infection. Platelets are small cells responsible for blood clotting. During sepsis, the two work together to block the lungs: neutrophils attach to the endothelium (the inner lining of blood vessels), platelets adhere to them, and together they form obstructions. This mechanism is called immunothrombosis: a combination of immune response and clotting.
Why older adults face greater risk
As people age, both the immune system and blood clotting change. Neutrophils respond less precisely, and platelets are more easily activated. This makes an uncontrolled immunothrombosis cascade more likely with age. Sepsis mortality rises sharply in people over sixty.
The real-time imaging in this study makes it possible to pinpoint exactly where the process breaks down. That matters for future treatments: if the coupling between neutrophils and platelets can be interrupted early enough, lung damage may be limited.
From mice to humans
The findings come from mouse models. Whether exactly the same mechanism operates in human lungs still needs to be confirmed. But the detailed visual data provide a foundation for targeted research into inhibitors of this specific coupling process. Several existing drugs that suppress platelet activity are now being reconsidered as potential components of sepsis treatment.