Timing-Dependent Clearance of p16-Positive Cells Mitigates Radiation-Induced Accelerated Aging.

Karla Valdivieso and colleagues used the INK-ATTAC mouse model to test whether the timing of senescent-cell clearance changes recovery after systemic genotoxic stress. Mice received sublethal whole-body irradiation and underwent genetic clearance of p16-positive cells either one month or four months later. Delayed clearance improved frailty measures, neuromuscular function, cognitive performance, blood-brain barrier integrity, and hepatic metabolic dysfunction. It also improved median survival. Early clearance did not produce the same benefits. Female mice showed a stronger response in several outcomes. The study argues that senescent-cell burden may be dynamic after radiation and that treatment timing could matter as much as treatment choice. The intervention was genetic and mouse-specific. It was not a human senolytic trial, and the radiation model does not reproduce ordinary aging or all cancer-treatment exposures. The results do not establish that fisetin, quercetin, dasatinib, or another commercial senolytic should be used after radiotherapy. They provide a preclinical rationale for carefully timed, indication-specific trials with safety monitoring.

These findings demonstrate that the timing of senescent cell clearance is a critical determinant of therapeutic efficacy following genotoxic stress.