The Latest Data from the Interventions Testing Program: Nicotinamide Riboside has No Effect on Mouse Life Span
The Interventions Testing Program (ITP) at the National Institute on Aging runs very rigorous, costly life span studies in large numbers of mice, picking a few interventions to test each year. The usual outcome is that a treatment with some interesting past results is found to have absolutely no effect on life span when run through the rigor of the ITP process. We should all bear this in mind whenever modest life span extension in mice is reported by researchers elsewhere in the community. Based on past ITP data, a great many such results are the result of chance or poor experimental design.
Will the ITP ever get around to testing senolytics or other potential rejuvenation therapies? They are dosing a group with fisetin, but overall their bias is towards approved drugs and existing supplements, calorie restriction mimetics, and similar classes of intervention that affect metabolism in well-explored ways: insulin signaling; blood pressure; inflammation; and so forth. Senolytics are likely not yet a well trodden enough path for most to get past the selection process.
Today's open access paper reports the latest set of interventions to have shown minimal, gender specific, or no effects at all on mouse life span in the ITP process. Of interest to the community here, nicotinamide riboside supplementation is one of these, and does not extend mouse life span. We might compare that outcome to the 2016 paper in which mouse life span does increase modestly, the human trial in which benefits to cardiovascular function result, and all of the other data showing improved stem cell and tissue function in mice and humans.
We might view the ITP as a steamroller encouraging us to run faster, to aim higher, to stop messing around with approaches to aging that do not and cannot have large enough effects to matter at the end of the day. The only goal worth aiming for is robust, sizable rejuvenation of the old. We have excellent starting points in the form of the SENS proposals for repair of cell and tissue damage, and the existence of the senolytics industry indicates just how fast things can move once impressive data is produced in animal studies. More of that sort of thing is much needed if we are to realize the promise of modern biotechnology.
The interventions for the present study were chosen for the following reasons:
(a) 17-α-estradiol (17aE2) is a relatively "non-feminizing" estrogen which shows reduced activation of classical estrogen receptors compared with 17-β-estradiol. It was reported that in UM-HET3 mice fed 4.8 mg 17aE2/kg (4.8 ppm) diet from 10 months of age, median male lifespans increased 12%, while 17aE2 did not alter female lifespan. Other researchers showed that using a threefold higher dose (14.4 ppm) from 10 months of age, pooled median male lifespans increased 19%; the 90% lifespan increased 12%, but females still did not benefit. Thus, only males were tested in the present study. To determine whether 17aE2 treatment is effective when initiated in older mice, males were treated beginning at 16 or 20 months of age, choosing middle age, and early old age before many natural deaths.
(b) Nicotinamide riboside (NR) is a precursor of nicotinamide adenine dinucleotide (NAD) via the cell's salvage pathway. Total NAD levels decline with age, in a wide range of species. Importantly, increasing NAD levels benefit a wide variety of tissues in species including mice and human beings. it has been suggested that NAD+ boosters may "..delay aging and age-related physical decline." It was reported that NR delays senescence of neural stem cells (SCs) and melanocyte SCs and increases mouse life span, even when given in old age (5% increase at 20 months of age).
It was reported that in mice and humans NR is bioactive when given by mouth, unlike most other nicotinamide derivatives. In a 2016 study NR improved liver function and protected against diabetic neuropathy. When fed to C57BL/6 J mice from 10 weeks of age, NR protects against high-fat diet (HFD)-induced obesity and promotes oxidative metabolism by increasing the NAD+/NADH ratio in muscle, liver, and brown adipose tissue. Researchers found that increasing NAD+ stores with NR supplementation improved muscle function and alleviated heart defects in a mouse model of muscular dystrophy. It was reported that an NR metabolite, nicotinamide, did not increase lifespan when started at 12 months in C57BL/6 J mice but improved some health outcome measures. Due to its benefits in a variety of diseases, and reports of benefits in mouse lifespans, NR treatment was proposed to increase lifespan in UM-HET3 mice.
c) Candesartan cilexetil (CC) is an angiotensin-receptor blocker, which lowers blood pressure and improves cardiovascular function and insulin sensitivity in obese, hypertensive patients. Importantly, angiotensin-receptor knockout increases lifespan of mice. Because CC is effective against age-related diseases, and sensitizes the body to insulin, and because the angiotensin-receptor knockout increases lifespan of mice, treatment with CC was hypothesized to increase lifespan.
(d) To maintain good quality protein in the body, heat shock proteins (HSPs) are vital. Geranylgeranylacetone (GGA) induces heat shock protein (Hsp70) in mammalian tissues and promotes insulin sensitivity in old mice, while it increases HSP expression in atrial tissue after heart surgery. Long-lived species, compared with related short-lived species within the same order, have elevated HSP levels in conjunction with better proteostasis. To test whether treatment with an established HSP inducer can increase lifespan in a mammalian model, UM-HET3 mice were treated with GGA.
(e) MIF098 ((3-(3-hydroxybenzyl)-5-methylbenzo[d]oxazol-2(3H)-one) is a macrophage migration inhibition factor (MIF) antagonist that regulates CD44 binding. MIF is a proinflammatory cytokine, so MIF098 reduces inflammation. This may include the chronic inflammation that increases with age, as suggested by the finding that MIF-knockout mice live significantly longer than controls. Because it is orally bioavailable and shows MIF inhibitory activity in mouse models of hyperoxic lung injury, as well as in other diseases, treatment with MIF098 was proposed to increase lifespan by decreasing chronic inflammation and disease.
Our new data show that nicotinamide riboside (NR) failed to increase lifespan. Only 17aE2 increased lifespan, and benefits in males occurred even when the drug was not fed until late middle or early old age (16 and 20 months of age, respectively). The range of ages for which treatment is effective suggests that benefits from 17aE2 do not depend on effects earlier in life, such as growth alteration. Interventions that are effective when started at a late age have considerable translational potential.
Hi there! Just a 2 cents.
''17-a-estradiol late in life extends lifespan in aging UM-HET3 male mice; nicotinamide riboside and three other drugs do not affect lifespan in either sex''
Yes, this is akin to endocrine/sex hormonal injection for women, oestradiol in menopause women (low oestrogen with age); estradiol/estrogen activates oestrongenic receptors int he brain, whole body/organs, these receptors activate telomerase/TERT, and thus increases telomerase processivitiy on 'smallest telomeres'..thsi will slowdown the Mitotic clock (telomeres shortening) and increase Healthspan (and a lilttle bit maximum). Same in women, lifespan is longer in women (9 supercentarian women vs 1 man supercentenarian -on 10 supercentenarians), due to oestrogenic receptors being more activated (due to women higher estrogen levels), while in men, it's 1 more step...aromatase enzymatic converting Testosterone/androgens/steroids to estrogen; Then, they get telomerase; like women, but that step hinders men because - 1 more step to getting estrogen/TERT/telomerase. While women, no such step/or much less, straight telomerase immediately. When women see shift of estrogen:testonerone ratio (reducing), then testosterone is stronger in them; their lifespan will shorten (because, now, like men, this conversion must happen). It is why there is solid benefit for women to obtain estrogenic therapy as they get in 50-60s range where menopause arrives for most. To main sex hormone levels; SE xHormones have an impact on telomerase and thys, on telomeres. The saying is: ''keep being 'active' (sexually)'' for as long as you can. When you lose that, it bad omen. You are entering the 'post-production' phase, for evolution, that means only 'late parenting' and then you are 'disposable' (next person to be born). As in, you have done your 'deed' to continue specie survival/humanity continuity (which requires women, birthing), once deed done, well...purposeless (I mean parenting 'grand-motheing' is in humans of course, and iwhy we live this long/grand ma longevity genes transfer (Supercentenarian Women -> give genes), so we live longer and evolution saw that 'late parenting' has its worth for specie survival and 'longevity. So we make children Later and Later...until we hit Menopause or Andropause. INfertility. sexually amorph. Don't lose the spark. Sexual Senescence = Bad. Very bad.
Ever heard people in their 80s: ''Absolutely...we do it...every other day''. They make it a (special) ritual. As for the 'sexual resources are relocated towards somatic maintenance/DNA preserving - at the expense of the wouldbe sexual resources'; well it's more nuanced. But yes, being overly reproduction = short lifespan. It'S why animals, like mice, who reproduce Massively, die young. But, in humans, it's delayed. And yes studies showed puberty entry correlates to lifsepan; mouse puberty immediately; humans puberty 10-13 years old; Greenland sharks reach puberty at 150 years (and they live +400 years). So there is a correlation, the later 'you bloom' the longer you live. That is due to 'neoteny', neotenous feature retaining; pre-puberty = tenous; after-puberty (if living long) = neotenous. Maintenace of 'youthful' child-like features into 'adult' age. In other words 'not maturing' staying 'immature'; maturity = aging/death (soon); immaturity = youth/non-aging/non-death. Maturity is Path Towards End. Immaturiy is Inverse/reversal (of aging/death); it amounts to rejuveneation; Re-Juvenil-ation; juven/jouven/jouvence/juvenil = child/immature. Becoming Again Child. Prepuberty. That is how your reverse aging -...by....Reversing It. The 'forward' 'Path' of it. Baby -> Child -> Adult -> Senior -> End.
Replace ->,... by <-. Or watch the film benjamin button.
Just a 2 cents.
PS: Males saw mostly the 'benefit' since they live shorter lives..females (mice) saw less benefit, they are already 'more optimized' for longevity (due to estrongen-telomerase). But, yes both benefit, males the most, because handicapped from birth; due to male handicappe longevity (to female).
"Will the ITP ever get around to testing senolytics or other potential rejuvenation therapies? Not soon, I'd imagine"
The ITP is currently testing the senolytic Fisetin in the 2018 cohort.
@Interested reader: Thanks, I somehow missed that. I will update the post accordingly.
The ITP is dosing fisetin at 600 ppm in feed. 600 ppm is 600 mg/kg or 600 ug/g in the feed. Mice eat 3g to 5g per day, meaning they are eating 1800 to 3000 ug per day. In 25g mice, that's 1800 / 25 = 64 ug/g or 64 mg/kg dosage.
The earlier animal study showing senolytic effects ( https://doi.org/10.1016/j.ebiom.2018.09.015 ) used 500 ppm in feed or 100 mg/kg when given via gavage.
The dosing schedules are different, but not so different that one would expect to see very different outcomes. We shall see.
@Reason: Thanks for adding your take on this experiment. I am looking forward to see the result.
By the way, I have noticed the following paper from the ITP pool trying to unify the mechanism of lifespan extension in the three compounds with a robust impact so far. With this respect, the result of the cohort 2017 where Rapamycin and Acarbose are tested together is going to be interesting. One would not expect meaningful synergies if the mechanism is common.
"Cap-independent translation: A shared mechanism for lifespan extension by rapamycin, acarbose, and 17α-estradiol"
https://onlinelibrary.wiley.com/doi/full/10.1111/acel.13345?campaign=wolearlyview
Nicotinamide, also known as niacinamide, is an amide of nicotinic acid, which is commonly known as niacin. Nicotinamide riboside (NR), on the other hand, is a chemically altered form of nicotinamide that has unique attributes. They are not the same.
In the above study it was an NR metabolite, nicotinamide, that did not increase lifespan and not NR. It doesn't appear the researchers tested NR consequently the jury is still out as to whether or not NR can extend lifespan?
If I am missing something here could someone please explain.
Why study NR by itself instead of in combination with Resveratrol, CoQ10, PQQ, and other substances that activate mitochondrial biogenesis and repair mitochondrial DNA? And why not do this after an extended fast, and compare it to doing nothing after an extended fast? I understand the need to test a supplement alone but enough is enough. Antioxidants don't do anything profound by themselves with a poor diet but they work in tandem with other approaches, synergistically. Mitophagy occurs during an extended fast. Why not boost those repair mechanisms with a robust approach? And if they didn't use real NR then it makes really question their motives😎
@Chuck Frasher
I would guess that the effects are not very cumulative not compound . Probably fasting will give the biggest effect with only marginal improvement using the supplements. Like getting the same effect with fast which is a day shorter, for example
@John
The paper states:
'As detailed in the Experimental Procedures, NR, CC, GGA, and MIF098 were each present in the diet pellets at about the amounts expected. Nicotinamide was detected in serum at the following levels (mean ± SD [n], ng/ml): controls 105 ± 46 (n = 19) and NR-treated 401 ± 212 (n = 31), with males and females pooled because their results were similar. Treated mice had significantly more nicotinamide (p < 0.0001 by Mann-Whitney test). No NR was detected, but the detection limit was 500 ng/ml, while that of nicotinamide was 25 ng/ml. Possibly, by the time NR was in the blood, it had already been metabolized to nicotinamide.
In a separate study, NR and its metabolites were tested in liver, brain cortex, plasma, gastrocnemius muscle, heart, kidney, iWAT (inguinal white adipose tissue), gWAT (perigonadal white adipose tissue), and leg muscle from 6- to 10-month-old UM-HET3 mice fed control or 1,000 ppm NR diet for 6-6.5 weeks, with 3 males and 4 females per group. The most interesting positive finding was lower levels (p = 0.004) of nicotinamide in cortex (though not liver) of NR-treated mice. NR-treated mice also had lower NR levels in cortex (but not in liver), compared with controls (p = 0.03). The ratio of NAD to NADH in the cortex was lower in NR-treated males (p = 0.012). These results are preliminary, because numbers of mice tested were low, and the diets were only fed to young mice for 6 weeks.'
The fisetin dosing schedule here is not the problem, the main problem is fisetin bioavailability
through absorption in the digestive tract. Every fisetin experiment is twin one - first that if it enter the bloodstream at all and will it do in sufficient quantity? Only after this successfully confirmed the second can be tested - if it is senolytic at all and if efficient enough. Stating how much the mouse is fed doesn't answer the question how much of it reaches the bloodstream. The synopsis on the NIH page doesn't answer this crucial question. Anybody found a link to more detailed description and how they assured the method of delivering fisetin? If their method (feed) is efficient fisetin will test positive as in previous tests on mouse and monkey. It they fail this step the experiment will come negative. Btw. There was estimate made that senolytics used once every 30 days to remove just 25% of senescent cells (used perpetually) cuts the likehood of cancer tenfold https://onlinelibrary.wiley.com/doi/10.1111/acel.13314. Anticancer combination with wogonin used previously and tested for safety was just about half to two thirds of a minimum senolytic dose. Schedule - 3 days with fisetin followed by 11 day break - seems more than sufficient.
Thanks Jones.