Immune drivers of venous thrombosis: orchestrating initiation, formation, and resolution within the hypoxic microenvironment

Venous thromboembolism (VTE) is a prevalent and life-threatening condition whose pathogenesis extends beyond a mere coagulation disorder to encompass a dynamic interplay with the immune system, a concept known as thromboinflammation. Hypoxia, a critical but often overlooked component of the venous microenvironment, serves as a master regulator that orchestrates immune cell responses throughout the thrombotic cascade—from initiation to resolution. This review synthesizes current evidence to establish an integrated framework linking the hypoxic microenvironment to immune-mediated venous thrombosis. We detail how hypoxia, arising from external exposure, pathological stasis, or intracellular metabolic reprogramming (pseudohypoxia), reprograms the function of key cellular players. This includes endothelial cell activation with glycocalyx shedding and adhesive molecule expression, neutrophil extracellular traps (NETs) formation, and monocyte recruitment. Collectively, these hypoxia-driven events create a prothrombotic milieu. Conversely, during the resolution phase, hypoxia-inducible factor (HIF)-1α signaling promotes angiogenesis, while hypoxia-induced metabolic shifts—particularly lactate accumulation—appear to influence macrophage polarization towards a pro-resolving phenotype. By elucidating the central role of immune cells as effectors of hypoxic signaling, this review highlights the hypoxic-immune axis as a pivotal pathway in venous thrombosis and points to potential immunomodulatory strategies for future therapeutics.