Sepsis endotheliopathy is emerging as a dynamic vascular syndrome
Sepsis is no longer well described as a single inflammatory storm. In this review, sepsis-associated endothelial dysfunction is presented as a moving target: early endothelial activation can support host defense, but the same vascular system can drift into barrier failure, vasoplegia, microcirculatory collapse, immunothrombosis, and multiorgan injury. The central argument is direct and clinically relevant. Bedside syndromes that once looked disconnected—capillary leak, refractory hypoperfusion, coagulation derangements, and organ-specific injury—fit into a shared endothelial injury program.
That framing matters because the endothelium is not a passive lining. It is an active organ system that maintains barrier integrity, regulates vascular tone, coordinates leukocyte trafficking, preserves hemostasis, and supports metabolic signaling across an estimated 750 billion endothelial cells in the adult body. During sepsis, those functions can fracture in parallel or in sequence, and the pattern is not uniform across organs. A patient with severe lung edema, for example, may be expressing a very different endothelial phenotype than a patient with persistent renal hypoperfusion or septic cardiomyopathy.
Four overlapping endothelial phenotypes shape the bedside picture
The review organizes sepsis endotheliopathy into four clinically recognizable modes. The first is barrier disruption with capillary leak, which drives tissue edema and the escape of protein-rich fluid into interstitial spaces. The second is vasoregulatory and microcirculatory dysfunction, a state in which vascular tone is impaired and systemic hemodynamics no longer guarantee adequate tissue perfusion. The third is proadhesive and procoagulant activation, where endothelial activation promotes immunothrombosis and microvascular obstruction. The fourth is leukocyte adhesion–driven inflammatory amplification, in which endothelial-leukocyte interactions intensify local injury.
These phenotypes are not isolated boxes. They overlap, evolve, and feed each other. A disrupted glycocalyx can amplify permeability, which can worsen tissue edema, which in turn can impair microvascular flow and oxygen delivery. Endothelial activation can initially be adaptive, yet when inflammatory signaling persists, the same pathway can tip toward structural injury. In practical terms, a patient may move from reversible endothelial activation into a state of overt organ failure without any single bedside parameter capturing the full transition.
Sepsis does not injure the vascular tree evenly. It selects its targets organ by organ.
Organ-specific vulnerability explains why sepsis does not behave uniformly
Pulmonary vascular injury is one of the clearest examples. In the lungs, glycocalyx degradation and junctional instability can produce capillary leakage, protein-rich edema, microvascular thrombosis, and impaired gas exchange. The result is acute lung injury or acute respiratory distress syndrome, where oxygenation worsens not simply because of alveolar inflammation but because the endothelial barrier itself becomes structurally unreliable.
Renal vulnerability follows a different path. Microvascular inflammation, impaired autoregulation, and heterogeneous perfusion can drive tubular injury, and the review places special emphasis on immune-endothelial crosstalk in this setting. The kidney depends on tightly regulated microcirculatory flow, so even modest endothelial dysfunction can create patchy ischemia and functional decline. In the brain, blood-brain barrier disruption within the neurovascular unit can permit immune cell trafficking, neuronal dysfunction, and cognitive impairment, contributing to sepsis-associated encephalopathy. Cardiovascular injury reflects impaired vascular tone, loss of hemodynamic coherence between macro- and microcirculation, and disrupted coronary microvascular perfusion, all of which can produce myocardial oxygen imbalance and septic cardiomyopathy.
Those organ-specific patterns help explain why standard resuscitation targets can look reassuring while tissue-level injury continues. A normalizing blood pressure does not guarantee that capillaries, mitochondria, and parenchymal organs have recovered. Sepsis can therefore look “stabilized” in the chart while endothelial failure still deepens in the microcirculation.
Biomarkers and physiologic surrogates need to track endothelial state, not just inflammation
One of the most useful contributions of the review is its push toward biology-anchored assessment. Rather than relying on a single biomarker or a static snapshot, the authors argue for integrated panels and serial trajectory-based evaluation. The logic is straightforward: if endothelial dysfunction evolves over time, diagnosis must also be longitudinal. A one-time measurement may miss the phase shift from protective activation to injurious dysfunction.
The review links biomarker assessment with bedside physiological surrogates. That combination is important because endothelial biology is not always visible in conventional laboratory values. Biomarkers can point toward glycocalyx injury, activation, or coagulation imbalance, while bedside surrogates can reflect perfusion coherence, capillary leak, or microvascular compromise. Together, they offer a more faithful readout of the endothelial state than systemic hemodynamics alone.
This approach also has implications for phenotype recognition. A patient with prominent vascular leak may require a different interpretive frame than one whose dominant problem is microvascular thrombosis. A patient whose course is marked by persistent endothelial activation may be biologically distinct from one who has already crossed into structural injury. The review treats those distinctions as clinically meaningful, not academic.
Trajectory-based assessment could refine sepsis trials and vascular-targeted therapy
The translational message is unusually concrete. If endothelial dysfunction is dynamic, then trials that enroll all-comers with sepsis may blur together biologically different patients and dilute treatment effects. A biomarker-enriched design could identify patients whose dominant problem is endothelial injury and who are therefore more likely to benefit from endothelial cell–targeted therapy. Serial monitoring could also help define whether an intervention is stabilizing the vascular barrier, improving microcirculatory flow, or reducing prothrombotic activation.
This has bedside relevance beyond trial design. Microvascular-informed resuscitation may eventually move clinicians away from a sole focus on systemic pressure and toward the tissue-level consequences of treatment. Endotype-guided care would ask a more precise question: which endothelial program is active in this patient right now, and which vascular pathway is failing first?
The review does not claim that these tools are ready for routine deployment. It does make clear, however, that the current state of sepsis care still lacks a robust way to classify vascular injury in real time. Without that, the clinician is often treating the macro-hemodynamic consequences of a process that is unfolding in the microcirculation.
A vascular framework for a disease that has resisted simple classification
Sepsis has long been defined by broad physiologic collapse, but that definition hides the vascular specificity of the syndrome. The endothelial lens clarifies why the same infection can produce edema in one patient, thrombosis in another, encephalopathy in a third, and cardiopulmonary failure in a fourth. It also explains why organ dysfunction often lags behind the initial infectious trigger and why recovery can be uneven across systems.
The practical value of this review lies in its refusal to treat the endothelium as background tissue. It reframes the vascular lining as a central participant in the pathobiology of sepsis and places endothelial state transitions at the center of diagnosis, risk stratification, and treatment development. In doing so, it gives clinicians and investigators a more coherent language for a syndrome that has remained notoriously heterogeneous.
The remaining challenge is operational. Biomarker panels, bedside surrogates, and trajectory-based classification still need validation in prospective clinical settings before they can guide routine decision-making. The conceptual framework is strong; the next test is whether it can reliably separate endothelial states at the bedside and improve the precision of sepsis care.