posted on Feb, 16 2010 @ 08:43 PM
[warning - semi-rant ahead!]
The Financial Times obviously gave the article somewhat of a spectacular title - " Scientists discover the secret of ageing " - but it's not just
forged to tingle our sense of sensation, but in my opinion also to misrepresent the facts. The article's first paragraph -
One of the biggest puzzles in biology – how and why living cells age – has been solved by an international team based at Newcastle University, in
- states the ageing of living cells to be one of the biggest puzzles. However, like SaturnFX and DBriefed, I'd like to disagree; I'm not up to date
on the topic of telomeres, but the first thing that occurred to me is that there are but very few cells that are supposed to keep alive. Of course we
all know that our skin sheds in a matter of weeks from generation, but it's not just our skin cells that have a short lifespan:
Each kind of tissue has its own turnover time, related at least partially to the workload endured by its cells. Epidermic cells, forming the easily
damaged skin of the body, are recycled every two weeks or so. Red blood cells, in constant motion on their journey through the circulatory system,
last only 4 months. As for the liver, the human body's detoxifier, its cells' lives are quite short - an adult human liver cell has a turnover time
of 300 to 500 days.
Cells lining the surface of the gut, known by other methods to last for only five days, are among the shortest-lived in the whole body. Ignoring them,
the average age of intestinal cells is 15.9 years, Dr Frisén found. Skeletal cells are a bit older than a decade and cells from the muscles of the
ribs have an average age of 15.1 years. When looking into the brain cells, all of the samples taken from the visual cortex, the region responsible for
processing sight, were as old as the subjects themselves, supporting the idea that these cells do not regenerate. 'The reason these cells live so
long is probably that they need to be wired in a very stable way,' Frisén speculates. Other brain cells are more short-lived. Dr Frisén found that
the heart, as a whole, does generate new cells, but he has not yet measured the turnover rate of the heart's muscle cells. And the average age of
all the cells in an adult's body may turn out to be as young as 7 to 10 years, according to him.
Why then, if the body remains so eminently capable of renewing its tissues, doesn't the regeneration continue forever? Some scientists believe this
is explained by the accumulation of mutations in the DNA, which gradually degrades its information. Another theory blames mitochondrial DNA, which
lack the repair mechanisms available for the chromosomes, whilst a third theory postulates that stem cells, which are the source of new cells in each
tissue, eventually grow feeble with age.
I apologise for the long quote, but the last paragraph puts it better then I could. And yet, it's not about the lifespan of individual cells - it's
about the complete system and the regeneration of needed cells. Even most of the average grandma's cells are around 10 years old, according to the
'nuclear' study quoted above. Of course the results of the study of ageing of individual cells can be applied to the stemcells that allow for
reproduction, but that is not how FT.com presented it - instead, it claims 'the secret
of ageing' has been discovered. Even the quoted study
doesn't touch the whole regeneration issue ; the scientists avoided it on purpose, because keeping your scope narrow increases your depth and/or
accuracy of investigation. FT.com clearly advocates the exact opposite, as demonstrated by the title and first paragraph. Maybe a
ageing has been found - a lot of useful information came forward in the study - but certainly not the one and only secret, and really, only when
applied to the very, very few cells that we keep our whole lives.
Not much of a secret when noone's in on it anyway.. ;]
P.S. Thanks for sharing, hope you don't mind my quasi-informal rant!