Freitag, 16. August 2013

Another large screening effort (Spindler et al.)

Gerontologists are ingenious, and consequently the field has never suffered from a lack of theories. (Arking)
The first time I heard of a large ongoing rodent study, which was screening substances for life extension effects, must have been years ago. I did not know how large it was exactly at that time nor if it ever got completed, but finally official data is emerging (1):
[This was a] large[...] study using a total of 2400 mice in which groups of 36 treated mice and 297 control mice were used to maximize the number of treatment groups
That's 58 interventions á n=36. You may have noticed the large control group. According to Spindler this improves power, which means that 36 animals per intervention suffices - normally you would like 40-50. Either way, the study is the largest such screen today or at least in the same ballpark as NIA's ITP. As we speak, Spindler et al. must be preparing more data from his mega-study to be published. So far we got two papers. Keep in mind that he really knows how to carry out mouse studies with mean lifespans of almost 1000d (1, 2), so the data must be taken seriously.

In the first of the two published papers Spindler et al. (1) screened the following substances for life extension in mice: blueberry, cinnamon, green and black tea, pomegranate, sesame, curcumin (two doses), morin and combined [pycnogenol, quercetin, and taxifolin]
While many of these phytonutrients reportedly extend the life span of model organisms, we found no significant effect on the life span of male F1 hybrid mice, even though the dosages used reportedly produce defined therapeutic end points in mice. The compounds were fed beginning at 12 months of age. The control and treatment groups were iso-caloric with respect to one another. A 40% calorically restricted and other groups not reported here [such a tease!] did experience life span extension.

Sonntag, 4. August 2013

What is aging?

"Aging is defined as the progressive deterioration during the adult period that underlies an increasing vulnerability to challenges and a decreasing ability of the organism to survive." (adapted from Masoro & Austad, ref. 1)

And aging matters:

"Discovering the biological basis of aging is one of the greatest remaining challenges for science." (Linda Partridge, ref. 2)

1. Handbook of the Biology of Aging, Seventh Edition (Handbooks of Aging) by Edward J. Masoro and Steven N. Austad

2. Annu Rev Physiol. 2013;75:621-44. doi: 10.1146/annurev-physiol-030212-183712. Epub 2012 Nov 26.
Genetics of longevity in model organisms: debates and paradigm shifts.
Gems D, Partridge L.