Aging as a clearance problem — and the schedule, not the molecule, becomes the variable
Two independent lines converged this fortnight on the same reframing: the problem is not only that damaged and senescent cells appear, but that the systems meant to remove them stop working. Stanford's Andreasson lab shows that aged tissue-resident macrophages fail to clear senescent neutrophils because of prostaglandin E2 receptor EP2 signalling, and that pharmacologic EP2 blockade reverses cognitive decline, sarcopenia, frailty and cardiac impairment in aged mice — an explicitly reversible driver, with the same EP2/senescent-neutrophil signature present in aged and diseased human tissue. On the senolytic side the interesting variable has shifted from which molecule to when and how often: a multitissue single-cell dissection of dasatinib+quercetin finds early-initiated, prolonged dosing outperforms late short courses, while the first triple-blind placebo-controlled fisetin trial in adults over 50 deliberately tests low-dose daily exposure with an inflammation endpoint rather than hit-and-run senolysis. Elsewhere: eight Myotis bat genomes place recurrent longevity evolution squarely in cancer pathways and DNA-damage response, aged mouse and human embryos turn out to fail implantation for mechanical rather than genetic reasons, and a two-cohort methylation study finds that ten 'healthy diet' scores barely agree on who is adherent. Nothing this week is a human efficacy result.
Continuous low-dose fisetin for 7 weeks — the regimen in the first triple-blind placebo-controlled fisetin trial in adults ≥50, with plasma suPAR (not senescent-cell burden) as the primary endpoint. Protocol only; no results yet.
Where the human evidence is
Count by statusEvidence-stage map
Evidence stage × investigator promise (1–10)Senolytics: the dosing schedule becomes the experiment
Multitissue single-cell profiling of dasatinib + quercetin: early-initiated, prolonged dosing outperforms short late-life courses
Hou, Chen and colleagues ran an unbiased multitissue single-cell analysis of D+Q in aged mice across aging phenotypes and tissue contexts, motivated by D+Q's known off-target effects, incomplete senescent-cell clearance and haematologic side effects. D+Q remodelled immunity (improved immune cell function with stable populations), reduced tissue inflammation and improved metabolic profiles, but the effect was strongly tissue- and cell-type-specific rather than uniform. The finding with the most practical weight: intervention initiated during early aging and continued long-term showed a greater tendency to mitigate aging readouts than shorter, late-stage treatment — which cuts against the intermittent late-life 'hit-and-run' schedule most clinics have adopted from the original mouse work. This is preclinical and hypothesis-generating on timing; it does not license earlier or longer D+Q in humans, where the only completed brain-endpoint trial (Neurotherapeutics 2025, mild Alzheimer's) was biomarker-null.
Read the paperFirst triple-blind placebo-controlled fisetin trial in adults ≥50: 100 mg/day for 7 weeks, primary endpoint plasma suPAR
Tavenier, Rasmussen and colleagues published the protocol for a triple-blind, randomised, placebo-controlled trial randomising generally healthy adults aged 50+ to 100 mg oral fisetin or placebo once daily for seven weeks. The primary outcome is the between-group change in plasma soluble urokinase plasminogen activator receptor (suPAR) from baseline to week 7; the co-primary safety outcome is occurrence and severity of adverse events; exploratory outcomes cover other inflammation, aging and cellular-senescence biomarkers plus frailty, physical and cognitive function. Two design choices matter for anyone advising patients: the dose is low and continuous rather than the high intermittent pulses used in most senolytic protocols, and the endpoint is a validated inflammatory/mortality-associated biomarker rather than senescent-cell burden — an implicit concession that senescent-cell quantification in humans remains unreliable. This is a published protocol only. There are no efficacy data, and fisetin still has no positive controlled human outcome trial.
Read the paperPipeline watch: two trials running, zero efficacy data
Retro Biosciences expands phase 1 of RTR-242 (lysosomal re-acidification / autophagy) from 76 to 108 healthy volunteers, adding two higher-dose cohorts
Retro Biosciences is adding two higher-dose cohorts to its Australian phase 1 safety study of RTR-242 in healthy volunteers aged 18–65, increasing enrolment from 76 to 108 (a 42% rise). The company states the compound is designed to restore lysosomal acidity and stimulate autophagy — processes that decline with age and are implicated in Alzheimer's and Parkinson's — and reports no major safety signals to date, which is the stated reason for escalating dose. No phase 2 timing has been disclosed and the programme has not yet been tested in older adults with cognitive decline. Treat this as a dose-escalation and safety milestone in a healthy young-to-middle-aged cohort, reported by the sponsor: it carries no efficacy information, and lysosomal-autophagy modulation as a geroprotective strategy remains unproven in humans.
Read the paperUTMB Moody Longevity Trial begins: randomised test of tirzepatide against epigenetic clocks and physical function in adults 55–70
Investigators at the University of Texas Medical Branch have opened one of the first trials to test a GLP-1/GIP agonist against aging endpoints in a general older population rather than a disease indication. Adults aged 55–70 who already meet clinical criteria for tirzepatide are randomised to 24 weeks of weekly tirzepatide followed by 12 weeks off drug, or to observation without medication; outcomes include epigenetic clock measures of biological age plus physical function. Principal investigator Thomas Blackwell notes prior work showing tirzepatide is generally well tolerated in older adults with improvements in body composition and vascular measures. Three cautions before this gets cited as evidence: the comparator is unblinded observation rather than placebo, the trial is powered for biomarker signal rather than function or outcomes, and the only randomised GLP-1 aging-clock result to date (semaglutide, ~9% slowing of PCGrimAge pace in adults with HIV-associated lipohypertrophy, Nature Communications) was explicitly framed by its authors as an early signal in a specific population. Muscle-mass loss with incretin therapy in older adults remains the key unresolved risk this design should be watched on.
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