Dynamic pathology for leukocyte-platelet formation in sepsis model

Area of Science:

• Microcirculation research
• Sepsis pathophysiology
• Vascular biology

Background:

• Sepsis involves complex interactions between leukocytes, endothelium, and platelets.
• Understanding real-time aggregation dynamics is crucial for sepsis management.
• Existing models lack detailed in vivo visualization of these processes.

Purpose of the Study:

• To evaluate dynamic, in vivo, real-time leukocyte-endothelium-platelet aggregation in a mouse model of sepsis.
• To assess the formation and dynamics of leukocyte-endothelium-platelet complexes (LEPCs) using advanced imaging.
• To identify critical microvascular sites involved in early sepsis pathology.

Main Methods:

• Utilized a lipopolysaccharide-induced sepsis model in green fluorescent protein transgenic mice.
• Employed two-photon laser-scanning microscopy (TPLSM) for in vivo visualization.
• Analyzed blood flow dynamics and LEPC formation in real-time.

Main Results:

• TPLSM enabled direct, single-platelet level visualization of LEPC formation.
• Septic mice showed decreased leukocyte rolling, velocity, and shear rate.
• Increased adherent leukocytes and platelet counts were observed, with dysfunction noted first in postcapillary venules.

Conclusions:

• TPLSM provides reliable in vivo real-time imaging of LEPC formation in sepsis.
• Early sepsis pathology involves LEPC formation and altered blood flow in postcapillary venules.
• Therapeutic strategies for acute sepsis should prioritize targeting postcapillary venules.