32 replies to this topic

[John Schloendorn]

Healthy lab mice have longer telomeres than they need (we know this because telomerase KO mice are fine and age normally for several generations, while each generation's telomeres get shorter and shorter).

So lengthening them in normal lab mice would take something that's already longer than necessary and make it way longer than necessary.

Overexpressing telomerase in these mice does mildly extend maximum life span, but because of the above, this has to be due to non-classical activities of telomerase protein, which have nothing to do with telomere lengthening.

(if you need pubmed references, find a recent a review by Maria Blasco)

Unlike mice, human telomeres seem to become critically short in a normal life span. So what would happen to us if we successfully lengthened them is I think a very interesting question.

[nowayout]

Healthy lab mice have longer telomeres than they need (we know this because telomerase KO mice are fine and age normally for several generations, while each generation's telomeres get shorter and shorter).

So is the lesson from this that normal mice do not die because of telomere shortening, or is it perhaps possible that they do die in part because of telomere shortening only in certain critical tissues that replicate a lot throughout life, e.g. white blood cells? The latter possibility does not seem to be excluded by the result you mention.

[Gern]

Lengthen telomeres in healthy mice and extend their lifespan. Then I will concede that telomeres really do play a role in determining maximum lifespan.

http://www.ncbi.nlm....pubmed/19013273