Intermittent rapamycin feeding recapitulates some effects of continuous treatment while maintaining lifespan extension

[Arhu]

13 February 2024,

Rapamycin, a powerful geroprotective drug, can have detrimental effects when administered chronically. We determined whether intermittent treatment of mice can reduce negative effects while maintaining benefits of chronic treatment. Chronic treatment induced glucose intolerance, which was partially ameliorated by intermittent treatment. Chronic and intermittent treatments increased lifespan equally in males, while in females chronic treatment resulted in slightly higher survival. The two treatments had equivalent effects on testicular degeneration, heart fibrosis and liver lipidosis. In males, the two treatment regimes led to a similar increase in motor coordination, heart rate and Q-T interval, and reduction in spleen weight, while in females, they equally reduced BAT inflammation and spleen weight and maintained heart rate and Q-T interval. However, other health parameters, including age related pathologies, were better prevented by continuous treatment. Hence, intermittent rapamycin treatment is effective in prolonging lifespan and reduces some side-effects of chronic treatment, but chronic treatment is more beneficial to healthspan.

https://www.sciencedirect.com/science/article/pii/S2212877824000334

[RapAdmin]

This is interesting… at very high doses, something to be aware of (not that anyone here is taking anywhere near this high a dose):

We used the highest rapamycin dose previously described to extend lifespan in both males and females [42 mg/kg diet) [9] and provided rapamycin in the food every other week. Intermittent rapamycin feeding increased serum rapamycin levels while the mice were on the drug (‘inter-on’), although not to the levels observed in continuously fed animals, while levels quickly fell to those of controls after one week off the drug (‘inter-off’). Concentrations in other tissues and their responses to weeks on and off intermittent treatment were sex- and tissue-specific. The adverse effects of a high dose chronic rapamycin treatment on glucose tolerance were ameliorated in inter-on females and inter-off animals of both sexes and were even restored to control levels in inter-off females. However, the effect of the drug on testicular pathology was not rescued by intermittent treatment. Both treatment regimes resulted in a comparable increase in heart fibrosis in males and liver lipidosis in both sexes, particularly females. Hence, these adverse effects of rapamycin treatment persisted to some extent with intermittent treatment.

On the positive side (in addition to life extension):

In males, the two treatment regimes led to a similar increase in motor coordination, maintenance of heart rate and Q-T interval and reduction in spleen weight.

In females, reduced BAT inflammation and spleen weight and maintenance of heart rate and Q-T interval were similar under the two regimes.

[Arhu]

Yes I still had to read the article when I posted it here. Of note though that intermittent dosing here was 7 days on, 7 days off. I don’t really know how that would translate to human dosing though, something like 20 weeks on/ 20 weeks off?

[Jonas]

The study is published by Molecular Metabolism on Feb 13, 2024, hot off press.
https://www.sciencedirect.com/science/article/pii/S2212877824000334?via%3Dihub
It has some interesting highlights that is somewhat surprising:

Caught my eyes is this paragraph:

Question: Isn’t reducing aged-related pathology the most important target to begin with?

The study also had different conclusions on male and female life extension with chronic usage which is the first time that I have heard about it. Their sample size seems to be very small, however.

[Jonas]

Chronic rapamycin feeding is a better option based on this mouse study from Germany (2024). Given that most people here are on an intermittent regimen, perhaps we can explore the chronic feeding benefit as indicated in the study:
The study compared the effects of intermittent and continuous rapamycin feeding on lifespan extension and various health parameters in male and female mice. The findings include:

1. Lifespan Extension:

• Both intermittent and continuous feeding extended median and maximum lifespan similarly in males.
• Continuous-fed females lived slightly longer than intermittent-fed females, with no significant difference in lifespan extension between sexes.

2. Health Parameters:

• Chronic rapamycin treatment improved motor coordination in males, while intermittent treatment did not show significant improvement.
• Continuous and intermittent treatment did not significantly affect running endurance in males, but chronic treatment improved endurance in old females.
• Rapamycin treatment did not significantly impact exploratory behavior in middle-aged mice of both sexes.

3. Glucose Intolerance:

• Chronic rapamycin treatment improved glucose tolerance, while intermittent treatment only showed a slight improvement compared to controls.

Overall, the study suggests that intermittent rapamycin treatment can provide benefits similar to chronic treatment in terms of lifespan extension, but chronic treatment may offer better prevention of certain health issues and improvements in glucose tolerance.

[John_Hemming]

What they do not study, however, is taking single doses with a period of time between them. They have chronic dosing with breaks.

That does not seem a sensible proposal to me.

[RapamycinCurious]

@Jonas

3. Glucose Intolerance:

• Chronic rapamycin treatment improved glucose tolerance, while intermittent treatment only showed a slight improvement compared to controls.

Their actual findings are more complex and not favorable:

Area under the curve (AUC) analysis of male glucose tolerance test (GTT) revealed significantly lower glucose tolerance of continuously rapamycin fed mice, which was partially rescued with intermittent rapamycin feeding during weeks on control chow, i.e. inter-off, while no improvement was measured when mice were back on rapamycin chow, i.e. inter-on. (

GTT of 12 months old C3B6F1 female mice. AUC analysis revealed significantly lower glucose tolerance due to continuous rapamycin treatment. This was partially rescued by intermittent rapamycin feeding during inter-on time periods, and glucose sensitivity was further improved to levels comparable to control mice when mice were fed control chow (inter-off).

Additionally, as quoted by RA but not yet highlighted:

The two treatments had equivalent [harmful] effects on testicular degeneration, heart fibrosis and liver lipidosis [i.e., NAFLD]. … Liver lipidosis was increased in both intermittent and continuously fed males and females

[RapAdmin]

Yes - but remember, the dose makes the poison. If those massive cajones of yours are starting to shrink, may I suggest a dose reduction

@RapAdmin

We used the highest rapamycin dose previously described to extend lifespan in both males and females [42 mg/kg]

[Melih]

Bryan Johnson probably has this data. I hope a member of his team sees this. Maybe they will be inclined to share an infographic of his testes.

[RapamycinCurious]

@RapAdmin

Yes - but remember, the dose makes the poison. If those massive cajones of yours are starting to shrink, may I suggest a dose reduction

We used the highest rapamycin dose previously described to extend lifespan in both males and females [42 mg/kg]

We may be fooling ourselves with a bit of an unconscious moat-and-bailey game. Many of our discussions of benefits are in studies using high-dose rapa, and it’s not clear that the doses humans are currently using are high enough to even be “low-dose” rapa (14 ppm in food) in the rodent studies — yet we often dismiss side-effects at higher dose in humans by saying “well, no one is using doses that high and Rapa News members aren’t reporting it.”

Note that both Neff et al. and Wilkinson et al. report testicular atrophy in male mice at 14 ppm in food (“low-dose” rapa).

[RapAdmin]

Its certainly true that we don’t know the optimal dosing for humans of rapamycin for longevity, and sadly, until there are some good clinical trials we won’t know.

Temporary testicular atrophy is also commonly seen in higher levels of caloric restriction and protein restriction, and is likely part of the evolutionary stress adaption of mammals to periods when food is scarce. There is a significant overlap between how rapamycin works (and its effects), and caloric restriction. And when the caloric restriction is removed, things return to normal from what I’ve read.

Protein Restriction (PR) treatment decreased testis-relative weight compared with Control rats. This finding agrees with the data of Ajuogu et al. (2020), Vawda and Mandlwana (1990), and de Souza Santos et al. (2004). This is relatable to testicular atrophy and/or alteration in the gonad’s biochemical state. Indeed, as suggested by Hanai and Esashi (2012), a decreased gonadic activity, as demonstrated by a low testosterone concentration, may cause testis involution.
Source: Protein vs. Energy Restriction Impact on Rat Testis’ Function, Redox Status, and Histomorphometry - PMC.

And, just as with mammals who are temporarily calorically restricted, then go on to have offspring, Transplant patients who stop rapamycin also go on to have children with no issues:

Conclusions

This survey does not provide any warning signal that pregnancies fathered by male patients exposed to immunosuppressive agents, notably the debated MMF/MPA, have more complications than pregnancies in the general population. (Source)

The present study revealed that low doses of rapamycin could lead to activation of autophagy in rat testes. This may be a self-protection mechanism of the cell in response to external stress. …
Notably, it was demonstrated that the damaged structure of seminiferous tubules and reduced number of sperm was reversible after withdrawal of rapamycin, which is consistent with previous research (3). Source: Rapamycin inhibits spermatogenesis by changing the autophagy status through suppressing mechanistic target of rapamycin-p70S6 kinase in male rats - PMC

Related reading: Possible Rapamycin Risks for Healthy Humans (Part 2)

You might also find this comparison of different dosing levels and rough estimates on the equivalent dosing for humans:

In a general sense, we can see that higher dosing (within the range tested in mice so far) the higher the dose, the greater the longevity effects. But this was for mice in sterile, pathogen-free environments (lab environments). Unfortunately we don’t live in that type of environment. The mice are highly immune compromised at these high levels, and would likely suffer/die in a regular environment with the typical infectious agent exposures. There have been situations where people are taking high daily dosing of rapamycin / rapalog (everolimus) … for example 10mg/day in some trials, and at least one young woman got sepsis and died… see details here: Rapamycin Taken with GFJ and EVOO - #11 by RapAdmin

And - while think the general belief is that its the AUC (area under the curve) of the exposure to rapamycin that matters (vs. the CMAX or half-life), I don’t think I’ve seen any research on this issue specifically with regard to lifespan - so I think we don’t know for sure of the impact of each of these variables independently on lifespan.

Here are the dose translations (and LS (lifespan) increase) from the other rapamycin studies:

Sirolimus Dose	Mouse mg/kg/day Dose	Mouse: Blood/Sirolimus Level	Human mg/kg/day Dose	Dose for 60kg Human	Daily Dose adjusted for longer half-life (/4)
4.7ppm	∼2.24	3 to 4 ng/mL	0.182 mg/kg	10.92 mg	2.73 mg
14ppm	~6.67	9-16 ng/mL	0.542 mg/kg	32.54 mg	8.135 mg
42ppm	~20	23-80 ng/mL	1.626 mg/kg	97.56 mg	24.39 mg
126ppm	~60		4.878 mg/kg	292.68 mg	73.17 mg
378ppm	~180	45 to 1800 ng/mL	14.634 mg/kg	878.04 mg	218 mg
Sirolimus Dose	mg/kg/day Dose	Blood/Sirolimus Level	Male Median LS Increase	Female Median LS Increase
4.7ppm	∼2.24	3 to 4 ng/mL	3%	16%
14ppm	~6.67	9-16 ng/mL	13%	21%
42ppm	~20	23-80 ng/mL	23%	26%

Based on the FDA animal to human dosing conversion guide here.

Note: ½ life for sirolimus in mice is approx. 15 hours, vs. approx. 62 hours in humans. So, mice metabolize sirolimus approximately 4 times faster than humans.

[desertshores]

I believe the bottom table gives us some insight into Dr. Blagosklonny’s dose recommendations.

[ageless64]

Does anyone know how the idea of a weekly rapa dose got started? I know it was one of the several dosing regimes in Joan Mannick’s 2014 study of everolimus (mTOR inhibition improves immune function in the elderly), but I haven’t found an earlier authoritative citation.

[Jonas]

@desertshores

Dr. Blagosklonny’

I believe Dr. Blagosklonny has said weekly or daily low dose is all a guessing game at this point. I know one scientist at Buck Institute (@kapahi_pankaj) is on a daily low-dose regimen when he is on rapamycin.

[DeStrider]

Weekly dosing is less expensive and more convenient. Especially when juiced with grapefruit.

It’s also the dosing schedule Dr. Kaberlein uses.

[RapamycinCurious]

@ageless64

Does anyone know how the idea of a weekly rapa dose got started? I know it was one of the several dosing regimes in Joan Mannick’s 2014 study of everolimus (mTOR inhibition improves immune function in the elderly), but I haven’t found an earlier authoritative citation.

Mannick discusses this in her interview with @Krister_Kauppi :

Joan Mannick on Rapamycin Longevity Series | Turning down mTOR to young levels may be good for aging

That should link to around 29:00, where they discuss it. See also Krister’s slide here.

She wanted to turn mTOR down partially but not completely (40-80%) to avoid full immunosuppression or other side-effects, her #1 priority being safety. So she worked with Novartis’ PK/PD experts, who had experience of wide ranges of doses in a wide range of clinical conditions, and they thought that any of the three tested doses would do the trick:

Modeling and simulation based on mTOR-mediated phosphorylation of its downstream target S6 kinase (S6K) predicted that the 20 mg weekly dosing regimen inhibited mTOR-mediated S6K phosphorylation almost completely, the 5 mg weekly dosing regimen inhibited S6K phosphorylation by more than 50%, and the 0.5 mg daily dosing regimen inhibited S6K phosphorylation by about 38% over the dosing interval (12).
https://www.science.org/doi/10.1126/scitranslmed.30098

Here is their reference 12; it’s been discussed on the Forum before.

That was modeling; they wanted to try all three, dose-ranging being part of the point of a Phase 1 trial. In the event, all three were well-tolerated, but 5 mg weekly seemed to have full efficacy with minimal side-effects, so they went with that going forward.

Thus, partial inhibition of mTOR-mediated S6K phosphorylation achieved with a relatively low dose of RAD001 may be as effective as nearly complete inhibition associated with high-dose RAD001 at enhancing the immune response of the elderly volunteers.

[Krister_Kauppi]

Yes, the first paper by Joan Mannick 2014 where she tested Everolimus was most likely what has impacted the longevity community around the weekly dosing around 6 mg once weekly (pubmed: 25540326).

On top of this in 2016 dr Alan Green, who is a clinical pioneer in the field, started taking Rapamycin. 6 mg once weekly. This became also the standard dose regime he prescribed to his patients especially in the beginning. In this time clip he talks about it.

https://www.youtube.com/watch?v=zWJQecgNloU&t=469s

Great to look back a bit and see how things started. I really like that the dose regime is based on Novartis knowledge about mTOR inhibition. But one question that raises to my mind is that were they too cautious around the dosing. This answer we will hopefully get an answer to this year because the researcher Adam Konopka is doing a dose response clinical study in humans where both Everolimus and Rapamycin is tested in low and high doses.

[ABL]

From prior posts most folks take weekly, although it seems the higher biweekly doses maybe more beneficial. I’ve wonder if taking a half dose twice a week might be closer to continuous dosing, while also lowering Mtor2 inhibition. Is there any logic to this?

On a sidenote, I have tried higher doses every 2 weeks and I believe that my body has a harder time adjusting to the large dosage after a long break. I may continue a little longer.

[Jonas]

@ABL

I’ve wonder if taking a half dose twice a week might be closer to continuous dosing, while also lowering Mtor2 inhibition. Is there any logic to this?

Intuitively, if you employ an agent to modify your system, it is more logical to have a more consistent input, as this would result in a more uniform output. The weekly dosage regimen was reportedly initiated by Joan Mannick, although the validity of this approach has not been replicated in other studies. However, a recent German study conducted on mice suggests that chronic dosing is preferable if the goal is to treat age-related conditions.

[Jonas]

Intermittent Weekly vs Daily Low Dose per Dr. Blagosklonny