5 replies to this topic

[james41]

I would like to share my opinion about aging in humans and mammals.

1/ I think aging is a semiprogramed process, not ment to self destruction of the individual but probably senescense is a programed price to pay to avoid cancer.By self destroying themself, cells are protect that random mutations and cancers kill the individual before the reproductive years hence preserving the specie .This program that kills cells when they reach certain number of divisions (in humans arround 50)is probablythe price to pay to avoid cancer at very early age.

2/ Aging is a multifactorial problem, and is party also caused by being warm blood, all warm blood animals experienze a progresive deterioration of function with age, some at a much higher rate(mice) than others at slower rate (, bats, humans, apes) but the aging process and free radical damage is very similar in both.
Reptiles and cold blood criatures, some of them experieze negligeble senescense, they dont loose functions as they age some even get strohger and stronger and more fertile as they age(turtles).So the free radicals produced to keep us warm have a lot to do with the progresive deterioration (aging) we all mammals experiece.

3/I think this mechanism is inherated in the basic chromosomes of all mammals because all mammals experienze senescense and funtional deterioration.It must be really enbeded in our genes because not a single mammal has been able to excape this.while some reptilians do.

4/ but it is not all bad news , it seems that Aging is quite a plastic process, meaning it can be delayed(but not avoid completly) by some few genes.as an example if you allowd to reproduce fruit flyes only when they are getting old, and you do this trough hundred and hundred of generations, the resulting generations after this old stage inbreeding live 50& longer than the starting models.this means that by only allowing reproduction at very old age, you induce natural selection to enchance thouse genes that are involved in longevity(probably the ones that modulate insulin, development and growth).

4/ there is no 100% correlation of aging rate, with weight, size or methabolic rate,as some aging studies tried to prove in the past (metabolic rate aging theory) but there is a correlation though to level of protection of a specie and lack of predators to the aging rates.What this means is that the more protected a specie had been trough evolution from being kill at a young age, the less effort they put in early multiple reproduction and the more in self live preservation(antiaging).Humans because of their inteligence were not an eassy prey, therefor their long lifes, bats despite being very related to mice live to 30 years, and mice only 3, probably as bats flying significally avoided predators, the same with mole rats that live extraordinary long lives, despite having a high metabolic rate(they live under the earth so much less predators than normal rats) the same with elephants and wheals,(they almost have no predators) also the same with birds that usually live much more than mammals the same size or metabolic rate not flying mammals.

5/ the less predators the more the chances the animal reproduce in an old age, the more chances they pass longevity genes to next generation and this through milions of years of evolution leads to longer life spans(as seen in the fruit flyes experiment mentioned in number 3.The long longevity of humans much longer than the reproductible age of the FEMALE, in my opinion is explained by the males. human males by reproducing at old age with fertile women pass their genes of longevity trough generation after generation.usually theories of aging only look at the female reproductive period but in my opinion this is a mistake in order to understand a specie you have to look at both sexes to fully inderstand the mechanism.Men can reproduce still in ther 90sh and even at this ages they still like very young women for reproduction, that is why female fertility doesnt really extend that much compared to other apes that also experized menopause , but young females had been made pregnant by old men trough a big part of evolution (many times forced to it).from an evolutionary perpective female fertile years will not really extend very fast as old men will still prefer young women for sexual intercourse as the chances to get them pregnant are much higher and therefor more sucesfull(natural selection here).Men who liked old women had less chances to have descendency(as female fertility decrease exponentionaly passed the 30sh therefor man´s genes who liked old women as a first choiced for reproduction extinguished.So the old pervs we all know may be the reason of our long lives after all.sad and shocking but probably true.

6/when you look at the pasticity of aging you see that in the flyes experiment , their life span increase 50% but also their developmen is delayed.it seems that the same genes involved in maturation and growth also have an impact in aging.This could explain why long live species have also very long period of childhood and maturation.Humans, wheels, elephants have straordinary long lives and also extraordinaly long development periods.when you compare the genetic code in first fruit flyes generation to the last generation(that live 50%) longer you see that there has been a small shift in a couple of genes not as many as you would expect for an impresive 50%longer life, only some of them, and guess what???this genes are the ones involved in insulin pathway, Mtor pathway and growth timing.

7/ So as a closure I dont think it will be eassy to completly avoid of aging, as it seems to be deeply part of our genes, probably attached to the very nature of us being warm blood and not dieing of cancer in childhood, but what is very good news though is that aging has plasticity and it seems that only a few genes can change the rate of aging as much as 50% longer life span.I dont thing neither that it is a coindidence that the genes that are alter by caloric restriction, that can make almost all mammals live 30% longer and healthy are the same genes related to growth, development timing and insulin and energy production.This means that there is a lot of hope for slowing aging in the near future !!!although completly avoid it or reverse it completly will take centuries and severe genetic manipulation, so extensive that could actually transform us in other specie.(completly avoid aging I think could be compare to make humans grow wings or 7 legs, in terms of genetic dificulty.)

please tell me what your thoughts are, if you agree to any of the points or not and please argument your reasoning.

thanks

Edited by james41, 05 October 2010 - 01:20 PM.

[Marios Kyriazis]

Aging is not controlled by a few genes, but is also dependant on other factors such as external random damage, the individual ability to deal with this damage and other hitherto unknown mechanisms. Your thoughts and comments are generally correct, and reflect the great majority of current opinion. However, I just happen to believe that there is a way to avoid aging, at least in the sense that it could be possible to live for an indefinite number of years. See http://www.elpistheory.info

Edited by mrszeta, 05 October 2010 - 02:02 PM.

[james41]

Aging is not controlled by a few genes, but is also dependant on other factors such as external random damage, the individual ability to deal with this damage and other hitherto unknown mechanisms. Your thoughts and comments are generally correct, and reflect the great majority of current opinion. However, I just happen to believe that there is a way to avoid aging, at least in the sense that it could be possible to live for an indefinite number of years. See http://www.elpistheory.info

thank you very much for your imput and link it looks very interesting , sorry if I didnt express myself correctly english is not my mother tongue, what I ment is that it is just few genes that have changed when you compared the first generation of fruit flyes, to the last 50%longer living generation after old age inbreeding.(few relatively to all the genes)And most of them are related to insulin, growth and ATP production.
So yes aging is modulated by many genes as you said , but what I was trying to point out is that the genes that already give substantially longer life are relatively few compared to the whole number of genes mice and flyes have.

For instansce everolimus the Mtor inhibitor that had just been proved to prolong life a 15% even when started after midle age in mice, changes few genes response even less than caloric restriction itself.I think this is a lot of hope

I think this relatively few genes involved in slowing aging are more realistic goals for the people that are already now in midle age.

[VidX]

".So the old pervs we all know may be the reason of our long lives after all.sad and shocking but probably true." - lol.. if I'll become old, I'll certainly be one of these pervs, but I'll have an excuse from now on ("the benefit for a human specie".).

[james41]

".So the old pervs we all know may be the reason of our long lives after all.sad and shocking but probably true." - lol.. if I'll become old, I'll certainly be one of these pervs, but I'll have an excuse from now on ("the benefit for a human specie".).

well many instinc enbedded in us make sense from a evolutionary point of view but in nowdays society they make no sense or are even against the law.I dont think the instints should be an excuse to break the law, to kill someone if he hurts you is also an instint still it is a crime.

In the times of birth control pills , condoms and when women can addopt and have artificial conception in their 50sh , it doesnt make sense that human males are atracted to nubile women.But this codings are still present in our brains.

I found some studies interesting,and at the same time very sad , some studies say that some women rated as being strikingly beautiful even on their 50sh,had facial proportions of 12 old yearsl old girls despite of course not looking like 12 years old girls the computer based on their facial proportions estimated an age on the face of 10 to 12 years old that means that the computer as mesure proportions , not skin or wrinkles thought that this faces belonged to little girls, as those facial proportions are only comun in little girls (like biger eyes, smaller nose higher foreheads,fuller lips, smaller more delicate jaws).

This means that the signs of beauty even in a women in her 50ish (that probably alredy had menopause so can not concive)are still extremely youth signs and the more this facial proportions look younger the more beautiful she is rated(facial proportions not other details) (the women has to have signs that she reached puberty to be considered sexually atractive)

[VidX]

^^interesting!