RS and SIPS differentially regulate endothelial anticoagulation capacity, and SIPS rather than RS may represent the predominant form of endothelial senescence during in vivo aging with respect to age-related dysregulation of blood coagulation.
Key Findings
Results
Plasma coagulation capacity was unexpectedly reduced in the presence of replicative senescent endothelial cells (RS-ECs) compared with young control cells, whereas stress-induced premature senescence ECs (SIPS-ECs) showed no such effect.
Coagulation capacity was assessed using calibrated automated thrombogram (CAT), a validated plasma coagulation assay
The reduction in coagulation capacity in RS-ECs indicates enhanced anticoagulation activity relative to young control endothelial cells
SIPS-ECs did not replicate this enhanced anticoagulation phenotype observed in RS-ECs
This finding was described as 'unexpected,' suggesting it contradicted prior assumptions about senescent cell pro-coagulant behavior
Results
RNA sequencing revealed distinct global transcriptional and coagulation pathway-related alterations between RS-ECs and SIPS-ECs.
RNA sequencing analysis was performed on both RS-ECs and SIPS-ECs
Both global transcriptional profiles and coagulation-specific gene expression pathways differed between the two senescence types
These transcriptional differences provide a molecular basis for the divergent functional coagulation phenotypes observed between RS and SIPS
The distinct gene expression profiles suggest RS and SIPS represent mechanistically separate cellular states
Results
Despite enhanced anticoagulation capacity of RS-ECs in vitro, thrombus formation was exacerbated in naturally aged mice in vivo.
A venous thrombus formation model was used to assess in vivo coagulation in naturally aged mice
The in vivo pro-thrombotic phenotype of aged mice contradicted the in vitro anticoagulant activity observed in RS-ECs
This discrepancy suggests that RS alone does not explain the age-related increase in thrombus formation observed in vivo
The finding highlights a dissociation between in vitro RS-EC behavior and the in vivo aged vascular environment
EC-specific SIPS mouse models were generated to isolate the contribution of endothelial SIPS to in vivo thrombosis
Venous thrombus formation was assessed histologically in these mice
Thrombus histological features in EC-specific SIPS mice resembled those observed in naturally aged mice
This finding directly links endothelial SIPS to the pro-thrombotic phenotype seen during natural aging
Results
Gene expression profiles related to blood coagulation were largely similar between endothelial cells isolated from naturally aged mice and EC-specific SIPS mice.
Endothelial cells were isolated from both naturally aged mice and EC-specific SIPS mice for gene expression comparison
Coagulation-related gene expression profiles showed substantial overlap between the two groups
This transcriptional similarity supports SIPS as the predominant form of endothelial senescence relevant to coagulation dysregulation during aging
The convergence of gene expression patterns between aged and SIPS models strengthens the biological plausibility of SIPS as a driver of age-related thrombosis
Discussion
SIPS, rather than RS, may represent the predominant form of endothelial senescence during in vivo aging with respect to age-related dysregulation of blood coagulation.
This conclusion is supported by the convergence of in vivo thrombus phenotype, histological features, and gene expression profiles between EC-specific SIPS mice and naturally aged mice
RS-ECs showed enhanced anticoagulation in vitro, inconsistent with the pro-thrombotic aged phenotype in vivo
SIPS-ECs did not show enhanced anticoagulation in vitro, and EC-specific SIPS mice developed more thrombus, consistent with the aged phenotype
The authors frame this as a demonstration of 'distinct contributions of endothelial RS and SIPS to blood coagulation'
What This Means
As people age, their risk of dangerous blood clots increases, and dysfunction in the cells lining blood vessels (endothelial cells) is thought to play a major role. Endothelial cells can undergo a process called 'cellular senescence,' where they stop dividing and change their behavior. There are two main types of senescence: replicative senescence (RS), which happens naturally after cells divide many times, and stress-induced premature senescence (SIPS), which is triggered by external damage or stress. This study investigated how each type affects the blood-clotting behavior of endothelial cells.
This research suggests that RS and SIPS have surprisingly different effects on blood coagulation. In laboratory experiments, RS endothelial cells actually reduced clotting activity compared to young cells — an unexpected finding suggesting they become more anticoagulant. However, SIPS cells did not show this effect. When the researchers looked at living mice, naturally aged mice had increased clot formation, which contradicted the anticoagulant behavior of RS cells seen in the lab. Mice engineered to have SIPS specifically in their endothelial cells also developed more clots, and these clots looked similar to those in naturally aged mice. Gene activity patterns in endothelial cells from SIPS mice and aged mice also closely matched each other.
These findings suggest that SIPS — the stress-triggered form of senescence — may be the more important driver of age-related blood clotting problems in blood vessel walls, rather than the gradual replicative senescence that comes from cells simply dividing over time. This distinction matters because it implies that factors causing cellular stress in blood vessels (such as inflammation, oxidative stress, or metabolic changes) may be key contributors to the increased clot risk seen in older individuals, potentially pointing toward new avenues for understanding and addressing age-related thrombotic disease.
Katayama A, Ikeda K, Kitani T, Yamazaki E, Ueno D, Ito F, et al.. (2026). Replicative and stress-induced premature senescence distinctively affect the endothelial anticoagulation capacity.. PloS one. https://doi.org/10.1371/journal.pone.0351140