Discontinuation of rapamycin results in robust but selective senescent enhancer activation and exacerbation of the SASP

[man_li]

Abstract:
The characteristic enhancer usage and transcriptional landscape of high-passage senescent cells are sensitive to rapamycin treatment, discontinuation of which results in robust but selective senescent enhancer activation and exacerbation of the SASP

https://www.pnas.org/doi/10.1073/pnas.2506321122

[Agetron]

Damn… the great results of rapamycin tamping down senescent cells was undone after a few weeks of discontinued treatment.

Because rapamycin treatment seemed to prevent certain features of senescence even in proliferatively arrested cells, we investigated whether these changes were stable upon rapamycin withdrawal.

HPGA cells withdrawn from rapamycin treatment reverted to a senescent-like state just 2 wk after drug removal, with a dramatic onset of senescent morphology and increased SA-β-gal staining (Fig. 2C and SI Appendix, Fig. S2B). RNA-seq of HPGA cells withdrawn from rapamycin versus those maintained in rapamycin showed a clear correlation between the genes induced upon rapamycin withdrawl.

Guess I will be on rapamycin for life… long-life.

[John_Hemming]

AIUI mTor activation kicks off SASP and inhibition reduces SASP. Not particularly complicated.

[lqgn]

If discontinuation is likely to induce reversal on the benefits, why are people suggesting cycling every 6 months / a year?

[Nlo]

Wasn’t there some study reported widely on this site that even one dose (or short term use) of Rapamycin could possibly provide the maximal life extension benefits? I understand that lifespan extension is different than health span, so living with increased SASPs may contribute to a worse health span, while still conserving the increased lifespan. Nonetheless, I find this report confusing/ disappointing.

Not to add another topic, but I also heard something about plasma withdrawal or donation (I think without adding back albumin) was recently found to accelerate aging in some way, rather than reducing aging.

All to say, I am starting to wonder if a lot of the more cutting edge, aggressive stuff that I do is actually detracting from my health. This comes up for me when I hear about these negative studies or see people like Asprey (who IMO does not radiate a youthful or healthy appearance) despite unlimited access and focus on his health.

Of course, my pessimism only lasts until the next strong positive study sparks my interest and buoys my optimism. But for today, my resolve is to refocus on the basics.

[amuser]

O3’s .02:

Direct take-aways for a 6 mg-weekly rapamycin user who plans a 3-month drug holiday

Aspect	What the paper shows	What it probably means for your regimen
mTOR inhibition blunts both the “growth-arrest” and the “SASP” enhancer programs of senescent fibroblasts	Continuous 500 nM rapamycin for ≥2 weeks erased H3K27ac on both enhancer sets and kept SASP genes low.	While your 6 mg weekly pulse will not produce the same constant exposure, it almost certainly lowers mTOR signalling for part of each week. Expect some degree of SASP suppression during the months you stay on drug.
Withdrawal re-primes the enhancer landscape, with a disproportionate rebound of the SASP module	Two-week wash-out triggered a surge of p65 binding and H3K27ac on the SASP enhancers; inflammatory transcripts (IL-6, IL-8, etc.) jumped, whereas the cell-cycle-arrest program stayed locked-on.	After you stop rapamycin for 3 months, existing senescent cells could up-shift their inflammatory output while remaining growth-arrested. In practical terms, systemic low-grade inflammation might rise for a while—even though your tissues will not suddenly start proliferating abnormally.
Rapamycin does not delete senescent cells	It merely dampens their enhancer activity. Stopping the drug leaves the same number—or more—senescent cells in place, now free to make SASP factors.	If your aim is to reduce senescent-cell burden, rapamycin alone is insufficient; consider pairing with bona-fide senolytics or shorter holidays.
Ligand loops matter	Withdrawal boosts TGF-β2-driven, p65-dominated enhancers; Activin-A-driven arrest enhancers stay on.	Any systemic rise in TGF-β family ligands or NF-κB activation during your drug holiday could amplify SASP rebound. Lifestyle factors that quell NF-κB (exercise, weight control, omega-3, etc.) may buffer this.
Translation caveats	Findings are in vitro fibroblasts, continuous drug, supraphysiologic dose; human weekly pulses haven’t been mapped at enhancer level.	Magnitude of rebound in vivo is unknown; systemic biomarkers (CRP, IL-6) or “deep aging” panels might help you see if a flare actually occurs.

Practical implications (no spin)

1. During the on-phase (weekly 6 mg for several months)

   • Likely partial SASP suppression → modest anti-inflammatory benefit.
   • No real reduction in senescent-cell number.

2. During the 3-month break

   • Senescent cells you accumulated remain.
   • Their SASP program may re-engage and even overshoot baseline for a time.
   • Clinical impact could range from trivial to a measurable uptick in inflammatory markers—data in humans are lacking (confidence: low-medium).

3. Mitigation strategies worth considering (evidence outside this paper)

   • Shorter holidays (e.g., 6–8 weeks) or alternating low-dose instead of a full stop.
   • Pairing the break with senolytics (dasatinib + quercetin, fisetin) or anti-inflammatories (low-dose NSAID, omega-3) if tolerated.
   • Tracking CRP, IL-6, or a commercial SASP panel before, during, and after the holiday to see if rebound is real for you.

4. Unknowns & limitations

   • Weekly pulses ≠ continuous exposure; the rebound could be muted—or already occurring between doses.
   • Only fibroblasts studied; other tissues may behave differently.
   • No clinical endpoints (frailty, cognition) tested.

Bottom line: The paper supports the idea that stopping rapamycin can let senescent cells crank up inflammatory SASP without re-entering the cell cycle. In a real-world weekly-pulse protocol, that rebound is plausible but unquantified. Continued biomarker monitoring is the only way to know if your planned 3-month holiday carries an inflammatory cost.

[Walter_Brown]

Great addition - these summaries are becoming much more beneficial!

[cl-user]

@amuser

Continuous 500 nM rapamycin

@Walter_Brown

Great addition - these summaries are becoming much more beneficial!

I agree but those summaries may be rather off. For instance 500nM of rapamycin would be a very high concentration and indeed they only used 10nM.

@The paper

fibroblasts maintained in 10 nM rapamycin were treated with the above ligands or IKK inhibitor TPCA-1 (500 nM) for 14 d, after which the cells were split into 2 wells, maintained in the indicated drug/ligand treatments, and either maintained in or withdrawn from 10 nM rapamycin treatment.

[Jonas]

Because nobody knows for sure how to dose rapamycin, it’s all guesswork, and no data supports any of the regimens for longevity purposes.

I myself do not cycle as much other than low dose regularly. My biomarkers have either improved or stayed the same. Subjectively, I feel better. And with grey hair turned into black (not all but more than half).

I suspect it accelerated my facial fat loss, although not significantly; it was noticeable.

I monitor my NLR ratio to be close to 1 as a benchmark of my immune system’s balance.

[AustraliaLongevity]

@Nlo

ut I also heard something about plasma withdrawal or donation (I think without adding back albumin) was recently found to accelerate aging in some way, rather than reducing aging.

Where did you hear this?

[Nlo]

Here’s where I read about it. It doesn’t negate benefits for folks paying for TPE protocols where they get replacement with albumin, but it certainly gives pause to the DIY’ers, like me, who thought they could get away with a freebie by donating plasma. We still might be reducing our forever chemicals, but at what cost to our anti-aging regimen.

Read more at:

Is this a new anti-aging fix or just hype? The plasma swap debate - Times of...

[AustraliaLongevity]

Good to know. Thanks for sharing this. I was under the impression that plasma donation was good.

[DeStrider]

I think this paper makes a valid point for weekly or more frequent Rapamycin dosing. Remember that SASPs increase senescent cell proliferation which allows the faster creation of senescent cells.

Most probably, using Rapamycin retards senescent cell formation and gives your body more time to clear out senescent cells. I’ll make sure to stay on a weekly dosing of 3 mg + GFJ (10.5 mg equivalent).

[AustraliaLongevity]

Does anyone else take carnosine? I hear that can help with senescent cells, and AGEs.