Re: Brain Insulin Signalling and Lifespan

[Guest guest]

It's not at all clear to me that that's what the study is saying. As

the mouse strain is almost certainly bred for that condition, and the

controls are typically the same strain, is it really telling us

anything about normal healthy mice? An 18% extension of an abnormally

shortened lifespan is certainly good if you happen to be a mouse of

that strain but how do we conclude the effect on normal naturally

aging mice? This is one of the main points I've taken from reading all

of Dr Walford's books. When evaluating study results which show longer

lifespans we must ask ourselves " compared to what " ? How did their

lifespan compare to the species? If there was no extension of lifespan

compared to the species then there was no slowing of aging.

Nick

>

> Hi folks:

>

> It seems this is saying that, at least in mice, even if obese and

> hyperinsulinemic everywhere else, just reduced brain insulin

> signalling can extend lifespan significantly.

>

> This seems to be another piece of evidence suggesting that the brain

> is a major link in the process by which the rate of body aging is

> regulated:

>

[Guest guest]

Hi Nick:

I don't disagree with anything you specifically say. But I don't

think I need to take back anything in my post either. The two are

not contadictory, imo.

The study did very specifically say that: " Thus, less Irs2 signaling

in aging brains can ................. extend the life span. "

So this does, it seems to me, represent an example where insulin

signalling in the brain, even without changed insulin elsewhere in

the body, extends lifespan.

Of course, as with all experiments, whether the results of this

experiment apply to normal humans, or even normal mice, can only be

proven beyond doubt with the appropriate experiments.

We have previously discussed here some evidence suggesting it is as

if all one has to do is fool one's brain, one way or another, into

believing there is a famine to get the benefits of CR. But in CR in

humans insulin levels throughout the body are reduced. What may be

of interest in this experiment is that levels of insulin in the

bodies of the mice were not changed, only in the brain, yet their

lifespans were extended.

So this looks to me like an additional piece of evidence in the same

general direction ............ suggesting that it may be that the

brain is a key link in the chain of events resulting in the longevity

effects of CR.

Or did I misunderstand what they say in this paper?

Rodney.

> It's not at all clear to me that that's what the study is saying. As

> the mouse strain is almost certainly bred for that condition, and

the

> controls are typically the same strain, is it really telling us

> anything about normal healthy mice? An 18% extension of an

abnormally

> shortened lifespan is certainly good if you happen to be a mouse of

> that strain but how do we conclude the effect on normal naturally

> aging mice? This is one of the main points I've taken from reading

all

> of Dr Walford's books. When evaluating study results which show

longer

> lifespans we must ask ourselves " compared to what " ? How did their

> lifespan compare to the species? If there was no extension of

lifespan

> compared to the species then there was no slowing of aging.

>

> Nick

>

>

> --- In , " Rodney " <perspect1111@>

wrote:

> >

> > Hi folks:

> >

> > It seems this is saying that, at least in mice, even if obese and

> > hyperinsulinemic everywhere else, just reduced brain insulin

> > signalling can extend lifespan significantly.

> >

> > This seems to be another piece of evidence suggesting that the

brain

> > is a major link in the process by which the rate of body aging is

> > regulated:

> >

>

[Guest guest]

Hi Rodney -

I'm sorry for my poor wording. As you point out, the study did say it

extended lifespan, and it clearly did for the strain tested. What I

meant was that the data doesn't show that it would extend lifespan in

normal mice. We need that experiment. It would seem to be simple to do

and it's crying out to be run.

Nick

> > >

> > > Hi folks:

> > >

> > > It seems this is saying that, at least in mice, even if obese and

> > > hyperinsulinemic everywhere else, just reduced brain insulin

> > > signalling can extend lifespan significantly.

> > >

> > > This seems to be another piece of evidence suggesting that the

> brain

> > > is a major link in the process by which the rate of body aging is

> > > regulated:

> > >

> >

>