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Author Topic: Are telomeres the cause of ageing?  (Read 2694 times)

Offline tanian

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Are telomeres the cause of ageing?
« on: 13/06/2009 12:59:42 »
Today is my birthday. And if you've seen Forrest Gump you'll know how I feel when I say it just won't do.

I'll confess my ignorance as a starting point here; I'm no biologist. I'm an enginner, and as a consequence I view ageing from an engineers point of view.

From what I understand of it, telomeres are the cause of ageing. They oversee the replication of our cells, and protect our DNA from disease etc. Which puts them in  the very epicentre of this ageing proess.

Every time a cell is copied, which happens in the most part at least every six weeks (with the exception of neurons, which stay with you for life) a tiny flaw is copied with them. The reason is the telomeres oversee the copying of the cell, but then begin to copy themselves - dismantling themselves as they go.

I'm going to use some nice round numbers here:
At thirty years of age, having your cells copied at a rate of once every six weeks, you will have copied this tiny corruption two hundred and sixty times, which means it is two hundred and sixty times magnified. By the time you reach sixty years of age you are composed almost entirely of cells with five hundred and twenty times corruption. If the flaw constituted 0.001% of a telomere, then in 260 corruptions, or 30 years, you would have 0.26%, and in 60 years or 520 corruptions you would have a telomere corrupted by 0.52%.

If the vast majority of a body is a maximum of six weeks old, why do we show signs of ageing? This corruption is the key.

My engineers perspective leads me to believe this is simply a flaw, an imperfection in the design of the human being: our regenrative process is broken. The reason why we age is something we can ultimatley fix.

I'd like to live long enough to see it.

Tell me I'm wrong... because if you don't, I'm going to ask you how to fix it.
« Last Edit: 13/06/2009 14:50:56 by chris »


 

Offline Kupac

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Are telomeres the cause of ageing?
« Reply #1 on: 15/07/2009 09:32:40 »
Telomere shortening is not the only cause of aging. Every time you copy DNA, there will be small errors, the copying process is not perfect. Evolution is driven towards perfect copying mechanism, however it can not be reached (it would breach the laws of physics I guess). These mistakes are called mutations. Mutations also arise because of different radiations and chemicals. As these mutations accumulate during your lifetime, your cells and organs become a bit more rusty; they wouldn't work as perfectly as they used to. This degradation process can not be avoided.

Also, you have certain organs (e.g. teeth, joints), which can only last for a certain amount of time, and then they fail. It would cost a lot for an organism to make these organs last longer. But is it worth it? As time goes, you have an increasing probability of having died in an accident or fight or some other reason. So spending resources in making your body survive longer is futile. Instead, it is better to put those resources into mating, and ensure the survival of your genes that way. As it turns out the latter one is a better strategy (as it is proven by evolution). The message you can hear from the distance of billions of years is: don't worry about aging, and have as much sex as you can, while you can :)
 

Offline Pwee

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Are telomeres the cause of ageing?
« Reply #2 on: 15/07/2009 12:49:20 »
This is a quote from wikipedia:
http://en.wikipedia.org/wiki/Ageing
Quote
Telomere Theory
    Telomeres (structures at the ends of chromosomes) have experimentally been shown to shorten with each successive cell division. Shortened telomeres activate a mechanism that prevents further cell multiplication. This may be an important mechanism of ageing in tissues like bone marrow and the arterial lining where active cell division is necessary. Importantly though, mice lacking telomerase do not show a dramatically reduced lifespan, as the simplest version of this theory would predict.
Reproductive-Cell Cycle Theory
    The idea that ageing is regulated by reproductive hormones that act in an antagonistic pleiotropic manner via cell cycle signalling, promoting growth and development early in life in order to achieve reproduction, but later in life, in a futile attempt to maintain reproduction, become dysregulated and drive senescence (dyosis). At the same time, castrated animals, although living somewhat longer, still experience senescence, even in the absence of reproductive hormones.
Wear-and-Tear Theory
    The very general idea that changes associated with ageing are the result of chance damage that accumulates over time.
Somatic Mutation Theory
    The biological theory that ageing results from damage to the genetic integrity of the body’s cells.
Error Accumulation Theory
    The idea that ageing results from chance events that escape proof reading mechanisms, which gradually damages the genetic code.
Evolutionary Theories
    See Theories of ageing in Senescence. These are by far the most theoretical; however, their usefulness is somewhat limited as they do not provide readily testable biochemically based interventions.
Accumulative-Waste Theory
    The biological theory of ageing that points to a buildup of cells of waste products that presumably interferes with metabolism.
Autoimmune Theory
    The idea that ageing results from an increase in autoantibodies that attack the body's tissues. A number of diseases associated with ageing, such as atrophic gastritis and Hashimoto's thyroiditis, are probably autoimmune in this way. While inflammation is very much evident in old mammals, even SCID mice in SPF colonies still senescence.
Ageing-Clock Theory
    The theory that ageing results from a preprogrammed sequence, as in a clock, built into the operation of the nervous or endocrine system of the body. In rapidly dividing cells the shortening of the telomeres would provide just such a clock. This idea is indirect contradiction with the Evolutionary Based Theory of Aging.
Cross-Linkage Theory
    The idea that ageing results from accumulation of cross-linked compounds that interfere with normal cell function.
Free-Radical Theory
    The idea that free radicals (unstable and highly reactive organic molecules, also named reactive oxygen species or oxidative stress) create damage that gives rise to symptoms we recognize as ageing.
Mitohormesis
    It has been known since the 1930s that restricting calories while maintaining adequate amounts of other nutrients prevents ageing across a broad range of organism. Recently, Michael Ristow has shown that this delay of ageing is due to increased formation of free radicals within the mitochondria causing a secondary induction of increased antioxidant defence capacity.[31]
Misrepair-Accumulation Theory
 This very recent novel theory by Wang et al. [32] suggests that ageing is the result of the accumulation of "Misrepair"...

As you can see, Telemere theory is just one of a dosen other ones. Of course as always the most likely is that they are all true in to some extent.
 

Offline Variola

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Are telomeres the cause of ageing?
« Reply #3 on: 16/07/2009 09:18:46 »
Quote
As you can see, Telemere theory is just one of a dosen other ones. Of course as always the most likely is that they are all true in to some extent.

So which one of those does Oil of Olay work against??  ;D
 

Offline MonikaS

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Are telomeres the cause of ageing?
« Reply #4 on: 16/07/2009 20:14:46 »
Quote
As you can see, Telemere theory is just one of a dosen other ones. Of course as always the most likely is that they are all true in to some extent.

So which one of those does Oil of Olay work against??  ;D

Oil of Olaz works - like any of those kinds of products - against the age of notes and coins in your purse. Those simply won't become old and wrinkled in it.
 

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Are telomeres the cause of ageing?
« Reply #4 on: 16/07/2009 20:14:46 »

 

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