IF a reverse-sequential pharmacological protocol — Alagebrium (ALT-711, 10 mg/kg/day oral, weeks 1–6) administered prior to Dasatinib + Quercetin (D+Q; 5 mg/kg + 50 mg/kg oral gavage, 3 consecutive days each in weeks 7, 9, and 11) — is administered to aged male C57BL/6 mice (22–24 months), with a head-to-head comparison arm receiving the established D+Q-first protocol (D+Q weeks 1, 3, 5; Alagebrium weeks 7–12),

THEN the Alagebrium-first arm will demonstrate ≥40% reduction in carotid-femoral pulse wave velocity (cfPWV) from baseline at week 12, compared to an estimated ≤25% reduction in the D+Q-first arm, alongside significantly greater reductions in aortic p16Ink4a-positive cell counts (≥60% vs. ≤40%), lower IL-6 and MMP-3 SASP cytokine levels in aortic tissue, and lower terminal LC-MS/MS-quantified pentosidine crosslink density,

BECAUSE the following mechanistic chain operates in the aged arterial wall:

1. Irreversible AGE crosslinks — particularly pentosidine and glucosepane — progressively stiffen the aortic ECM in aged rodents, mechanically compressing vascular smooth muscle cells (VSMCs) and endothelial cells; this increased substrate rigidity activates integrin-focal adhesion kinase (FAK) and YAP/TAZ mechanotransduction pathways that upregulate the cyclin-dependent kinase inhibitors p16Ink4a and p21, locking proliferation-competent VSMCs into a state of "mechanosenescence" [SPECULATIVE — the link between AGE-crosslink stiffness specifically and mechanotransduction-driven p16 upregulation is inferred from general mechanobiology of substrate rigidity and senescence; direct in-context evidence is lacking].

2. This mechanosenescence creates a continuous replenishment flux of new senescent cells in the arterial wall, meaning that a D+Q-first protocol — which clears the existing senescent cell pool but leaves the stiff, crosslinked ECM intact — will be rapidly undermined: the rigid matrix continues to drive new VSMC senescence during weeks 1–6, partially refilling the cleared population before Alagebrium is introduced in weeks 7–12 (Roos et al., Aging Cell, 2016 — demonstrating vasomotor improvement with D+Q but without ECM structural restoration) (Senolytics alleviate chronic vasomotor dysfunction)[https://doi.org/10.1111/acel.12458].

3. Alagebrium, by breaking α-diketone-based AGE crosslinks and reducing downstream vascular resistance in obese and diabetic rats, reduces aortic stiffness and restores more physiological wall shear stress distributions (Wang et al., 2015) (Alagebrium reduces vascular resistance and inhibits neointimal hyperplasia)[https://pmc.ncbi.nlm.nih.gov/articles/PMC4865061/]; this ECM softening reduces integrin-mediated mechanical stress on VSMCs in weeks 1–6 of the Alagebrium-first protocol, thereby removing the upstream mechanotransductive driver of new senescence induction [SPECULATIVE].

4. With the mechanical senescence-induction signal attenuated by week 6, the residual senescent VSMC population is now...

SENS category: GlycoSENS

Key references: • doi.org/10.1016/j.exger.2021.111416 • doi.org/10.1111/acel.12458]. • doi.org/10.1038/s41591-018-0092-9]. • doi.org/10.1111/acel.12458] • doi.org/10.1038/s41591-018-0092-9]