Endotheliopathy within the thromboinflammatory network of sepsis-induced coagulopathy

Sepsis represents a life-threatening syndrome driven by dysregulated host responses in which inflammation, coagulation, and endothelial dysfunction intersect. Increasing evidence suggests that endotheliopathy is a dynamically interacting component linking systemic inflammation, immunothrombosis, and microvascular dysfunction. Rather than acting as a singular upstream trigger, endothelial dysfunction evolves in parallel with platelet, neutrophil, and monocyte activation, forming a self-amplifying thromboinflammatory network that drives organ failure.

The vascular endothelium maintains hemostatic balance through anticoagulant pathways mediated by thrombomodulin, endothelial protein C receptor (EPCR), and antithrombin, supported by a protective glycocalyx layer. During sepsis, pathogen- and damage-associated molecular patterns (PAMPs and DAMPs) trigger the degradation of the glycocalyx, deactivation of the vascular stabilizing regulator Tie2, and shedding of thrombomodulin and EPCR, ultimately leading to capillary leakage and a procoagulant endothelial phenotype. Concurrently, excessive immunothrombosis, characterized by tissue factor expression, platelet activation, and neutrophil extracellular trap (NET) formation, amplifies endothelial injury and impairs microcirculation. Sepsis occurs across a spectrum of clinical states, with sepsis-induced coagulopathy (SIC) representing an early, potentially reversible stage marked by thrombin generation and suppressed fibrinolysis, whereas progression to overt disseminated intravascular coagulation (DIC) entails consumptive coagulopathy and organ failure. Biomarker-based phenotyping using syndecan-1, soluble thrombomodulin, angiopoietin-2, and NET-related markers enables mechanistic stratification and therapeutic targeting.

Recognition of endotheliopathy as an interacting component of SIC provides a unifying framework for understanding disease progression and identifying temporally appropriate therapeutic targets. Emerging endothelial-directed therapies, including heparanase inhibitors, Tie2 agonists, antithrombin and thrombomodulin supplementation, and NET-targeted interventions, represent a paradigm shift toward precision medicine in managing sepsis. Integrating endothelial biomarkers and immunothrombotic phenotyping into adaptive trial designs will be critical to advancing approaches for personalized vascular and immune modulation. Recognition of endotheliopathy as the central driver of sepsis-induced coagulopathy provides a unifying framework for understanding the mechanisms involved and driving therapeutic innovation.