Wild-type rodents are CRed

[Guest guest]

Hi All,

The below papers appear to indicate that more extreme

forms of CR may be ineffective. Pdfs are available, but

please request these offlist to me at old542000@....

1. Harper JM, Durkee SJ, Dysko RC, Austad SN,

RA.

Genetic modulation of hormone levels and life span in

hybrids between laboratory and wild-derived mice.

J Gerontol A Biol Sci Med Sci. 2006

Oct;61(10):1019-29.

PMID: 17077194

Previously we showed that mouse stocks derived from

wild-caught progenitors are long-lived relative to

genetically heterogeneous mice derived from

laboratory-adapted strains. Here we replicate this

life-span effect, and show that F2 hybrids between

wild-derived and laboratory-derived stocks have

intermediate survival patterns. Moreover, wild-derived

mice are small, lean, and slow to mature, and have low

serum insulin-like growth factor-I (IGF-I) relative to

genetically heterogeneous mice. These traits, too,

were at intermediate levels in the F2 hybrids.

Furthermore, serum IGF-I at 6 months was a significant

predictor of life span in two different populations of

F2 hybrid mice. Pooling across stocks, life span was

negatively correlated with body weight and serum IGF-I

levels, and positively correlated with age at vaginal

patency and serum leptin levels. Overall, these

finding suggest that wild-derived mice harbor alleles

that increase longevity, perhaps through effects on

growth, maturation, and early-life hormone levels.

Table 1. Summary Statistics for Life-Span Data.

==========================================

--------===Survivorship (d)

Stock N Log-Rank p Value* Adjusted^# p Value Mean Life

Span (d)===25th Percentile 50th Percentile 75th

Percentile 90th Percentile

==========================================

DC 40 - - 787 668 817 896 982

Id 40 .0001 .0005 957 738 1004 1169 1230

IdB6F2 50 .01 .04 868 726 864 1036 1160

IdDCF2 41 .07 .14 846 678 892 980 1084

Ma 40 .02 .06 829 556 871 991 1189

MaB6F2 50 .9 .9 724 555 678 908 1047

==========================================

---* Survival of the indicated stock versus the DC

control.

---# Adjustment for multiple comparisons was made

using Holm's Stepdown Bonferroni Procedure.

---DC = diversity control; Id = North-Central Idaho;

Ma = South Pacific Island of Majuro.

2. Effects of Intended Weight Loss on Morbidity and

Mortality: Possible Explanations of Controversial

Results

Berentzen, Tina; Sorensen, Thorkild I.A.

Nutrition Reviews, Vol. 64, No. 11 2006: 502-7

Long-term, population-based, observational studies

have shown that intended weight loss does not always

reduce the mortality associated with obesity. The

effects of weight loss on mortality may be a balance

between the effects of the loss of harmful abdominal

and ectopic fat mass and the loss of beneficial

peripheral subcutaneous fat mass and lean body mass.

-- Al Pater, PhD; email: Alpater@...

________________________________________________________________________________\

____

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www.nextag.com

[Guest guest]

Hi Al and all others,

I am not sure if I understand the science right, but

here is my interpretation:

1. from a previous study CR did not increase the

lifespan of wild mice.

2. in this study CR was done on a cross bread of wild

mice and laboratory mice? And there was no CR effect

seen?

3. CR is seen in laboratory mice, this is relatively

well documented.

The question that comes to mind if I understand the

above correctly is:

Will CR work better in humans if those humans have a

metabolism which resemble laboratory mice i.e. put on

weight easily, grow fast, mature early?

Will CR work less or maybe not at all in humans who

are naturally lean and have good insulin response?

If my thinking on this is correct naturally obese

people would benefit the most from CR.

Thanks

Sig

--- Al Pater <old542000@...> wrote:

> Hi All,

>

> The below papers appear to indicate that more

> extreme

> forms of CR may be ineffective. Pdfs are available,

> but

> please request these offlist to me at

> old542000@....

>

> 1. Harper JM, Durkee SJ, Dysko RC, Austad SN,

>

> RA.

> Genetic modulation of hormone levels and life span

> in

> hybrids between laboratory and wild-derived mice.

> J Gerontol A Biol Sci Med Sci. 2006

> Oct;61(10):1019-29.

> PMID: 17077194

>

> Previously we showed that mouse stocks derived from

> wild-caught progenitors are long-lived relative to

> genetically heterogeneous mice derived from

> laboratory-adapted strains. Here we replicate this

> life-span effect, and show that F2 hybrids between

> wild-derived and laboratory-derived stocks have

> intermediate survival patterns. Moreover,

> wild-derived

> mice are small, lean, and slow to mature, and have

> low

> serum insulin-like growth factor-I (IGF-I) relative

> to

> genetically heterogeneous mice. These traits, too,

> were at intermediate levels in the F2 hybrids.

> Furthermore, serum IGF-I at 6 months was a

> significant

> predictor of life span in two different populations

> of

> F2 hybrid mice. Pooling across stocks, life span was

> negatively correlated with body weight and serum

> IGF-I

> levels, and positively correlated with age at

> vaginal

> patency and serum leptin levels. Overall, these

> finding suggest that wild-derived mice harbor

> alleles

> that increase longevity, perhaps through effects on

> growth, maturation, and early-life hormone levels.

>

> Table 1. Summary Statistics for Life-Span Data.

> ==========================================

> --------===Survivorship (d)

> Stock N Log-Rank p Value* Adjusted^# p Value Mean

> Life

> Span (d)===25th Percentile 50th Percentile 75th

> Percentile 90th Percentile

> ==========================================

> DC 40 - - 787 668 817 896 982

> Id 40 .0001 .0005 957 738 1004 1169 1230

> IdB6F2 50 .01 .04 868 726 864 1036 1160

> IdDCF2 41 .07 .14 846 678 892 980 1084

> Ma 40 .02 .06 829 556 871 991 1189

> MaB6F2 50 .9 .9 724 555 678 908 1047

> ==========================================

> ---* Survival of the indicated stock versus the DC

> control.

> ---# Adjustment for multiple comparisons was made

> using Holm's Stepdown Bonferroni Procedure.

> ---DC = diversity control; Id = North-Central Idaho;

> Ma = South Pacific Island of Majuro.

>

> 2. Effects of Intended Weight Loss on Morbidity and

> Mortality: Possible Explanations of Controversial

> Results

> Berentzen, Tina; Sorensen, Thorkild I.A.

> Nutrition Reviews, Vol. 64, No. 11 2006: 502-7

>

> Long-term, population-based, observational studies

> have shown that intended weight loss does not always

> reduce the mortality associated with obesity. The

> effects of weight loss on mortality may be a balance

> between the effects of the loss of harmful abdominal

> and ectopic fat mass and the loss of beneficial

> peripheral subcutaneous fat mass and lean body mass.

>

> -- Al Pater, PhD; email: Alpater@...

>

>

>

>

________________________________________________________________________________\

____

> Sponsored Link

>

> Online degrees - find the right program to advance

> your career.

> www.nextag.com

>

>

________________________________________________________________________________\

____

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