Aging

Discussion in 'Biology & Genetics' started by TheAlphaWolf, Dec 8, 2005.

  1. TheAlphaWolf Registered Senior Member

    Messages:
    445
    We're all familiar with aging. Becoming shorter, balding, wrinkles, less energy, less libido, etc.
    Aging is one of the cruelest things ever. It's just sad (ID? HA! right.). But anyway I guess that's life.
    Yes, I know, telomeres and free radicals and mutations and all that crap, but I need more detail. What exactly causes aging? I'm looking for specifics... especially about why old people have less energy than young people. Someone said that because the mtDNA is degraded, and therefore the mitochondria don't work as well, but I'm highly skeptical of that.
    why do some people (especially men) go bold? is the trait in an X chromosome? why wrinkles? why everything else?
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. Hercules Rockefeller Beatings will continue until morale improves. Moderator

    Messages:
    2,828
    The causes of aging are not fully understood, so if you’re looking for precise explanations then you are bound to be disappointed. It is a very complex biological phenomenon. The general senescent phenotype is characteristic of each species. One major theory sees our metabolism as the cause of our aging. According to this theory, aging is a by-product of normal metabolism; no mutations are required. Some of the oxygen atoms taken up by the mitochondria are reduced insufficiently to reactive oxygen species (ROS). ROS can oxidize and damage cell membranes, proteins, and nucleic acids.

    General wear-and-tear and genetic instability is another theory of aging and are among the oldest hypotheses proposed to account for the general senescent phenotype. As one gets older, small traumas to the body build up. Point mutations increase in number, and the efficiencies of the enzymes encoded by our genes decrease. Moreover, if a mutation occurred in a part of the protein synthetic apparatus, the cell would make a large percentage of faulty proteins. If mutations arose in the DNA-synthesizing enzymes, the rate of mutations would be expected to increase markedly.

    The mutation rate in mitochondria is many times faster than the nuclear DNA mutation rate. It is thought that mutations in mitochondria could (1) lead to defects in energy production, (2) lead to the production of ROS by faulty electron transport, and/or (3) induce apoptosis. Age-dependent declines in mitochondrial function are seen in many animals, including humans.

    In addition to environmental factors, there is also a genetic aging program -- several genes have been shown to affect aging. So as human life expectancy increases due to our increased ability to prevent and cure disease, we are still left with a general aging syndrome that is characteristic of our species. This is worth remembering because unless attention is paid to the genetic mechanisms controlling our aging syndrome, we risk ending up like Tithonios - the miserable wretch of Greek mythology to whom the gods awarded eternal life, but not eternal youth.<P>
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. TheAlphaWolf Registered Senior Member

    Messages:
    445
    interesting... would that decrease the energy someone has?
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. Hercules Rockefeller Beatings will continue until morale improves. Moderator

    Messages:
    2,828
    Mitochondrial dysfunction leading to a reduction in the efficiency of glycolysis, I suppose. (Just guessing.)

    Another part of our aging program is that, as we age, there is a genome-wide reduction in the expression of tissue maintenance genes. This is why we become so decrepit (in addition to oxidative damage).

    This was beautifully demonstrated in C.elegans. (Not a vertebrate, but still relevant.) The worms have a short life cycle. I forget how long they live – something like 7 days. What some researchers did was take advantage of the fact the C.elegans genome has been sequenced (~20,000 genes) and that there are whole-genome cDNA microarray chips available. They took worms at regular timepoints during ~7 day lifetime and expression profiled the whole genome. So what they complied was a profile of every gene’s expression pattern over the lifetime of the organism. What it showed was exactly that: muscle maintenance genes gradually switched off as the worms aged.

    I don’t have a reference off hand, but I could find it if you want.
     
  8. Dinosaur Rational Skeptic Valued Senior Member

    Messages:
    4,885
    There was an article on aging a few weeks ago in the NY Times Science section, which is a standard feature on Tuesdays.

    A researcher showed that natural selection could be used to evolve fruit flies with extended life spans. He prevented fruit flies from reproducing early in their normal life spans. Subsequent generations of flies maintained thier ability to reproduce later than normal and had extended life spans. I think he managed to double or triple the life span.

    He claimed that his research strongly suggested that long life tends to be selected against under normal circumstances. He further claimed that there is no reason to suppose that the life span of a species could not be extended to extremes not imagined at present.

    Unfortunately for us, it would probably take thousands of generations to double or triple the life span of human beings. Note, however, it seems as though the increased life span would include a lot of extra years (perhaps decades) of mental and physical vigor not associated with people currently living to be 80 plus.
     
  9. fadingCaptain are you a robot? Valued Senior Member

    Messages:
    1,762
    Average lifespan has increased greatly recently.

    http://www.lef.org/anti-aging/research2.html

    Up 60% from 1900 to 1988.

    Within our lifetime we may see tremendous strides that allow us to circumvent the maximum life span issues. With nanotechnology, the genetic issues in particular. First we will have to gain a clearer understanding of the mechanisms of aging and their roles.
     
  10. ArtofWar Registered Senior Member

    Messages:
    121
    Birds baby! It's all about the birds...
     
  11. Enigma'07 Who turned out the lights?!?! Registered Senior Member

    Messages:
    1,220
    Wrinkles are caused as the collagen of our skin becomes worn and it becomes less able to stay taut as in young age, so physics takes over. (entropy, path of least resistance, equilibrium- whatever you want to call it)
     
  12. Dinosaur Rational Skeptic Valued Senior Member

    Messages:
    4,885
    The research mentioned by me in an earlier post to this thread was done by Michael R. Rose and is described in the 6 December 2005 NY Times. Perhaps a search using his name might turn up some interesting information.

    His research notes that there is little evolutionary advantage to longevity. This is not a startling new concept. Evolution via natural selection can be viewed as genes attempting to maintain themselves in future generations. Hence, there is no evolutionary advantage to an individual surviving past the age at which his/her offspring are self sufficient and able to reproduce.

    Rose was able to significantly extend the life span of fruit flies by delaying the age at which they reproduced. This created evolutionary pressure for fertility at a later age and as a byproduct pressure for longevity. He claims that his work indicates that there is no inherent reason why living organisms cannot have extremely long life spans.

    As mentioned in some of the citations in this thread, the average life span has doubled in the past few hundred years, while there has been little, if any, increase in the age of the oldest individuals.

    It is interesting that a tendency for many women in modern technological cultures to delay having children until much later than was the case 50 or more years ago. This is likely to result in increased longevity for females if the trend becomes wide spread.

    BTW: There has been a bit of furor from various religious types relating to Rose's work. Apparently, some think it is blasphemous to try to use evolution (a dirty word) to estned human life. Their attitude is amusing when you consider that it would require many thousands of generations to double the life span.
     
  13. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Messages:
    23,198
    You generaly know what you are talking about in bioloogy etc. Thus I wonder if you have an opinion on the value of Leucine suppliments? Because you may not have seen my post in the Human Sciences forum thread "Ideal Human Nutrition", I repost part here for your comments:

    Acouple of days ago I read:
    www.news.bbc.co.uk/2/hi/health/4502862.stm

    The essence of which is that leucine helps old folks, like me, avoid the normal wasting away of muscle. Good discussion, two different universities, published results in J. of Physiology etc.

    From article:

    "Straight after a meal, the rate of syntheses {of muscle} doubles prompted by the arrival of large amount of amino acids."

    "..in older animals...the amino acid stimulus prompting synthesis is less effective ... however the breakdown of proteins is not, leaving older animals with less protein than their younger counterparts."

    "But when...boosted levels of ...leucine, the balance of synthesis and breakdown was restored."
    (The research used 8 vs. 22 month old rats.)

    I take vitamins, with minerals, & antioxidants and just bought pills containing 2.36g of BCAA aminoacids as follows (Portuguese names):
    Valina: 0.694g
    Isoleucina: 0.694g (yes, same number not copy error)
    Leucina: 0.972g
    Vitamina B6: 2mg

    What is difference between:
    (1)BCAA amino acid and simple amino acids?
    (2)Isoleucina and Leucina?

    What is likely reason Valina was included in this mix?

    Is the amino acid mix in fish and chicken significantly different from beef and other red meats, which I rarely eat?

    I am toying with idea of adding a fourth meal per day.
    What do you think of this idea?
    Perhaps I just take my new pill when going to bed as a new shot of what seems to be the important amino acid?

    Thanks for any information you (or others reading can give)
    ___________
     
    Last edited by a moderator: Dec 17, 2005
  14. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Messages:
    23,198
    As I still have no responce to my questions, which have now fallen off the page, I re -post main part of a prior post which was from BBC news extracts from a J. of Physiology article:

    "Straight after a meal, the rate of syntheses {of muscle} doubles, prompted by the arrival of large amount of amino acids."

    "..in older animals...the amino acid stimulus prompting synthesis is less effective ... however the breakdown of proteins is not, leaving older animals with less protein than their younger counterparts."

    "But when...boosted levels of ...leucine, the balance of synthesis and breakdown was restored."
    (The research used 8 vs. 22 month old rats.)

    I take vitamins, with minerals, & antioxidants and now pills containing 2.36g of BCAA aminoacids as follows (Portuguese names):
    Valina: 0.694g
    Isoleucina: 0.694g (yes, same number not copy error)
    Leucina: 0.972g
    Vitamina B6: 2mg

    QUESTIONS:

    What is difference between BCAA amino acid and simple amino acids?
    I think that Isoleucina and Leucina are the same chemical but "optical isomers" of each other. - Is this correct? Are they both equally biologically active or is one useless?

    What is likely reason Valina was included in this mix?

    Is the amino acid mix in fish and chicken significantly different from beef and other red meats, which I rarely eat?

    I am toying with idea of adding a fourth meal per day. What do you think of this idea?
    Perhaps I just take my new pill when going to bed as a new shot of what seems to be the important amino acid, especially for older folks?

    Thanks for any information
     
  15. Dinosaur Rational Skeptic Valued Senior Member

    Messages:
    4,885
    To live for a long time, you need to choose grandparents who lived for a long time.
     
  16. Enigma'07 Who turned out the lights?!?! Registered Senior Member

    Messages:
    1,220
    But that would be assuming genetics is the only factor. The environment must be considered as well.
     
  17. TheAlphaWolf Registered Senior Member

    Messages:
    445
    I was watching an anderson cooper special about aging, and they concluded that these things are things all or almost all OLD people have:
    A: good attitude. Humor, positive outlook, etc.
    G: genetics can play a role
    I: uh... crap i forgot.
    N: no smoking?
    G:... damnit. forget the damn acronym.

    Exercise, lots of vegetables and not much meat, and what i mentioned before.
     
  18. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Messages:
    23,198
    If you are also old, I think I can supply two of the five in list above:
    "failing memory"

    I also note you forgot to answer any of my questions. Three "forgots" and Three "remembered" - you must be older than me.

    Please Register or Log in to view the hidden image!

     
  19. Dinosaur Rational Skeptic Valued Senior Member

    Messages:
    4,885
    I think that genetics put an upper bound on how long a person is likely to live. Environmental factors and behavior determine how much of that potential life span an indvidual will actually enjoy.

    This seems to be generally true of many charterististics affected by both genetics & environment/behavior.

    A recent evolutionary experiment with friut flies resulted in extended life spans. The experimenters prevented large numbers of fruit flies from reproducing until after the median age at which they normally had offspring. They did this for many generations, causing the ability to reproduce at a later age to have an evolutionary advantage.

    Longevity doubled or tripled in the resulting generations, which was a side effect of the ability to reproduce at a later than normal age.
     
  20. squishysponge Registered Senior Member

    Messages:
    71
    Personally I believe aging is a preprogrammed response. Some may call it a disease which i believe is one that is genetic. If you think in terms of evolution, why shouldnt it be? It ensures evolution of the species. It ensures constant improvements through natural selection, blah blah. Ideally, in evolutionary terms, the next generation should be better than the previous, and hense with aging and later death, it ensures that whats left is the better genes and that the weaker is gone. Evolution ensures this with aging. Which is why I think as we understand more about genetics we may find a gene somewhere or genes that program the aging response and hense be able to 'cure' aging.
     
  21. Hercules Rockefeller Beatings will continue until morale improves. Moderator

    Messages:
    2,828
    That's hardly a controversial stance

    Please Register or Log in to view the hidden image!

    . As I said above, it is the accepted theory amongst scientists that study the aging process that there is a genetic program that drives aging independent of any environmental influences that might accelerate it.


    I’m not so sure. It’s true that altering single genes in invertebrates can dramatically change lifespan, but we know that the genetics of aging in mammals is considerably more complex. The same gene alterations have little or no effect in mice. Aging is likely controlled by many genes and by complex feedback mechanisms from many cell types all over the body. Lifespan and senescence is a fundamental cellular process that I doubt we will be able to overcome.<P>
     
  22. squishysponge Registered Senior Member

    Messages:
    71
    I am optimistic that aging process can be reduced even completely halted given the full understanding of sciences and aging. Assume we map and understand absolutely the entire human genomic structure and all its possibilites and have broken down and identified the genes responsible for aging, and perhaps by changing this we can ensure aging is halted.

    Aging is like a combination of gradual failure and inefficiencies of many physiological functions of the body until death. Like the immune system gradually gets worse, and organ quality is upkept by the body's immune system and repair capabilities whos efficiency decreases with time. Perhaps finding the gene or way to upkeep the bodys immune system, etc, can mean prolonging life.
     
  23. TheAlphaWolf Registered Senior Member

    Messages:
    445
    I didn't forget, I just didn't know the answers

    Please Register or Log in to view the hidden image!


    Evolution just doesn't work that way. Ok I guess it does in a few instances, but I think the reason for aging is not that. Evolution does not care about what you do after you have had your last offspring. There are plenty of organisms that do not age, such as fungi, protists, and plants, so that disproves your hypothesis.
    Animals are different because animals move around and even if aging wasn't genetically programmed, they would still age. Older animals are less fit, therefore they reproduce less. This is why aging DOES have a genetic basis... there is a certain age at which animals stop reproducing, so genes that have a bad effect on the organism after that age do not get selected against. These genes accumulate, and that's aging.
    Also, it is (usually) more advantageous to reproduce early in life than later. By reproducing later, there is a greater chance that you will get eaten or die before getting a chance to reproduce.
    (I'm not sure that made much sense... I feel really incoherent right now... you tell me)
     

Share This Page