Stiffness Drives Endothelial Senescence and Inflammation in Aging and Doxorubicin-Induced Vascular Dysfunction

Age-related arterial stiffening affects over [~] 60% of elderly individuals and is a major independent risk factor for cardiovascular mortality. Similarly, doxorubicin-induced cardiotoxicity affects up to [~] 48% of cancer patients, limiting therapeutic options. Here, we demonstrate that vascular stiffness mechanically amplifies endothelial senescence phenotypes, identifying the extracellular matrix as a potential therapeutic target for both cardiovascular aging and chemotherapy-induced vascular dysfunction. Using polyacrylamide (PAAm) hydrogels to mimick soft (3.3 kPa) and physiological (30 kPa) arterial stiffness, and glass to reproduce pathological stiffening, we show that substrate rigidity enhances senescence markers including {beta}-galactosidase activity, DNA damage, and inflammatory cytokine secretion in both therapy-induced and replicative senescence models. Critically, we identify a protective effect at physiological stiffness, where IL-6 and IL-8 secretion is minimized compared to both softer and stiffer conditions, suggesting an optimal mechanical therapeutic window. RNA sequencing reveals stiffness-dependent activation inflammatory pathways including chemotaxis and leukocyte migration. Our findings position vascular stiffening not just as a consequence but as driver of endothelial dysfunction, creating a positive feedback loop amenable to therapeutic intervention. These mechanobiological insights provide rationale for developing mechanical-based therapies in cardiovascular medicine and cardio-oncology, where targeting tissue mechanics alongside conventional approaches could improve clinical outcomes.