Hypothesis: Beta-hydroxybutyrate (BHB) supplementation improves younger parenchymal cells' and immune cells' ability to detect and respond to senescence-associated secretory phenotype (SASP) signals. This would preserve the regenerative benefits of transient senescence while making chronic senescent cells functionally redundant and easier to clear.

Mechanistic Reasoning: Senescent cells act as "experienced communicators"—younger cells may progressively lose the ability to "listen" to their signals. This idea aligns with well-documented age-related declines in TGF-β receptor expression, integrin signaling, and chemokine responsiveness across aging tissues. BHB works through several distinct mechanisms—AMPK activation, mTORC1 inhibition, and histone β-hydroxybutyrylation—that together boost cellular receptivity to external signals. AMPK activation, for instance, upregulates TGF-β receptor II expression and restores integrin-linked kinase signaling. Meanwhile, mTORC1 inhibition shifts the cell's priorities away from autonomous proliferation and toward attending to extracellular cues. Direct histone modification likely alters chromatin accessibility at genes encoding SASP receptors. This provides a mechanistic pathway for BHB to restore "listening" without requiring senolytic clearance.

Testable Predictions: If this hypothesis holds, then: (1) BHB-treated young fibroblasts and epithelial cells will show increased TGF-β receptor expression and downstream SMAD signaling when exposed to exogenous SASP, compared to untreated controls; (2) BHB-treated mice undergoing acute wound healing will exhibit faster closure even with equivalent or slightly increased senescent cell burden, because recruited immune cells respond more robustly to SASP gradients; (3) in models of chronic senescence accumulation—such as irradiated or progeroid mice—BHB treatment will paradoxically reduce pathology despite maintaining senescent cell numbers, as functional tissue responsiveness gets restored; (4) transcriptomic profiling of BHB-treated versus control tissues will reveal upregulation of SASP receptor pathways (TGFβR2, CXCR2, IL-6R) alongside downregulated mTORC1 signatures.

Falsifiability: This hypothesis would be falsified if BHB treatment in acute wound models either (a) fails to accelerate healing despite increased SASP responsiveness markers, or (b) worsens pathology in chronic senescence models without altering senescent cell burden—indicating that impaired listening isn't the limiting factor. Additionally, if BHB simply acts as a senolytic or senescence-preventive agent without affecting signal reception pathways, the specific mechanism proposed would be incorrect.

Integration with Existing Findings: The observation that BHB induces reversible quiescence (Oct4/p27 upregulation, Lamin B1 retention) rather than senescence may reflect a phenotypic state more receptive to external guidance—quiescent cells typically exhibit heightened receptor expression and response to environmental signals compared to proliferating cells. This aligns with BHB's pro-health effects in progeria models via autophagy-mediated proteostasis, potentially clearing damaged proteins that would otherwise trigger chronic SASP production. We lack human trials, but the hypothesis generates specific, measurable endpoints for first-in-human studies combining BHB supplementation with senescent cell burden biomarkers in tissue repair contexts.