The tree · branch 1 of 8
Worn-out cells
Cells that have stopped dividing but will not die, and sit in the tissue giving off signals that inflame their neighbours. They build up with age; clearing them makes old mice healthier and longer-lived.
Of the twelve published hallmarks of ageing, this branch groups one: cells that stop dividing but will not die, and poison their neighbours.
Where this branch stands
required: the year cannot arrive until this branch is handled; handled when 2 treatments are in the clinic- 2043handled, in the middle run
- 0of 5 in the clinic already
- first humanfurthest stage reached
Nothing under this branch is in the clinic yet. In each run of the model a year is drawn for every treatment from its range, and the branch counts as handled when the second of those years arrives. Across all the runs, the middle year this branch is handled is 2043.
5 treatments and tools
listed by how soon each could reach its next rung- A drug clears aged cells from a person
Next rung within 5 to 20 years. Some cells stop dividing but do not die, and sit in tissue giving off signals that inflame their neighbours; they build up with age.
- A drug that clears aged cells beats a sham treatment in a controlled trial
Next rung within 5 to 20 years. Clearing aged cells (cells that have stopped dividing but will not die, and inflame their neighbours) from a person is one thing; making a person measurably better is another.
- A drug that clears aged cells relieves knee osteoarthritis
Next rung within 5 to 20 years. Osteoarthritis of the knee, the wearing-away of the cartilage that cushions the joint, is the most common reason an older person cannot walk without pain.
- A person's immune cells are engineered to hunt down aged cells
Next rung more than 20 years away, if ever. Drugs that kill aged cells (cells that have stopped dividing but will not die, and inflame their neighbours) hit many cell types at once.
- Clearing aged cells makes old animals live longer
Next rung more than 20 years away, if ever. Aged cells (cells that have stopped dividing but will not die, and inflame their neighbours) build up with age.
What would move this
the next test each treatment needs, and the branch's own lineA controlled trial in people in which a drug that kills these cells improves an age-related condition on its primary outcome, or a regulator's approval of one.
- A drug clears aged cells from a person Next rung: in clinical use. A regulator somewhere has approved it, or it is in routine use in a named clinical setting, so a doctor can give it to a patient outside a trial. Settled by peer-reviewed trial reports for the first-human rung; a regulator's approval record, or a named clinical setting's published practice, for the clinic rung.
- A drug that clears aged cells beats a sham treatment in a controlled trial Next rung: in clinical use. A regulator somewhere has approved it, or it is in routine use in a named clinical setting, so a doctor can give it to a patient outside a trial. Settled by a peer-reviewed trial report or the trial registry's posted results for the first-human rung; a regulator's approval record for the clinic rung.
- A drug that clears aged cells relieves knee osteoarthritis Next rung: first human. At least one person has had it, with a public record of that result. Settled by the peer-reviewed trial report; the trial registry's posted results; the regulator's approval record for the clinic rung.
- A person's immune cells are engineered to hunt down aged cells Next rung: first human. At least one person has had it, with a public record of that result. Settled by peer-reviewed reports; the trial registry when a first person is treated; the regulator's approval record for the clinic rung.
- Clearing aged cells makes old animals live longer Next rung: first human. At least one person has had it, with a public record of that result. Settled by the peer-reviewed trial report; the regulator's approval record for the clinic rung.
Its history
the handled year, computation by computationThe year was first computed on 17 October 2026, with this branch handled in the middle run by 2043. Every estimate under it is still a first pass. From the second computation on, this section charts the branch's handled year run by run, so a reader who sees the year at the top move can tell which branch moved it.
What the story so far says about it
the promises, the self-experiments and the papers that bear on this branchPromised, in public
- 27 October 2016Unity Biotechnology: Drugs that kill worn-out cells preventing, halting or reversing diseases of ageing in people, with first trials in the near future; no year.
- 29 February 2024David Sinclair: A result already in hand: that a supplement combining a booster of the cell-energy molecule NAD with a drug that kills worn-out cells had been proven, in a trial, to reverse ageing in dogs.
On the record
- 1 October 2026Senolytics dasatinib and quercetin in metabolic dysfunction-associated steatohepatitis: a proof-of-principle randomized, controlled trial
- 17 August 2020UNITY Biotechnology Announces 12-week data from UBX0101 Phase 2 Clinical Study in Patients with Painful Osteoarthritis of the Knee
- 7 October 2024Implausibility of radical life extension in humans in the twenty-first century
- 3 January 2023Hallmarks of aging: An expanding universe
- 6 June 2013The Hallmarks of Aging
- 5 January 2019Senolytics in idiopathic pulmonary fibrosis: Results from a first-in-human, open-label, pilot study
- 18 September 2019Senolytics decrease senescent cells in humans: Preliminary report from a clinical trial of Dasatinib plus Quercetin in individuals with diabetic kidney disease
- 12 May 2022Foreword to the Aubrey de Grey and Charles Brenner debate (Let's Talk Longevity newsletter)
- 15 June 2004Escape Velocity: Why the Prospect of Extreme Human Life Extension Matters Now
- 3 February 2016Naturally occurring p16Ink4a-positive cells shorten healthy lifespan
- 2 November 2011Clearance of p16Ink4a-positive senescent cells delays ageing-associated disorders