Viewing 22 reply threads
  • Author
    Posts
    • #16493
      JoGo
      Participant

      I was just wondering if someone has a legit explanation of why cells age?

    • #111107
      jonmoulton
      Participant

      "Why" is a difficult question for science to tackle. How do cells age? That question can get you loads of information. When and where do the changes associated with aging occur? Again, there is plenty of literature addressing that. What happens to cells as they age? Sure, again that is a common research topic and plenty has been done. "Why", however, is more a question for philosophers than for science — it’s not very testable (technically, hypotheses about "why" are often not falsifiable).

      Try some keywords using the term "senescence" in Wikipedia, PubMed, etc. and you’ll find entries into the topic of aging. Generally though they won’t answer the "why" question.

    • #111108
      JoGo
      Participant

      Sorry, what I meant to ask is HOW cells age. I’ve read lots of articles online but none seem to give an answer that is globally excepted. I was just curious if there is a globally accepted theory?

    • #111111
      plasmodesmata11
      Participant

      Look up telomeres!

    • #111121
      jonmoulton
      Participant

      Other useful search terms include:
      free radicals
      somatic mutations
      lamin A, progerin

      There are various factors that contribute to aging of a cell. I don’t think you’ll find a single switch that explains it all. An interesting topic in aging is the disease Hutchinson-Gilford progeria, which ties in with the Lamin A topic I mentioned above.

    • #111162
      animus
      Participant

      Ooh, I can add to what plasmodesmata11 said about telomeres.

      Telomeres are repeating (and I’m pretty sure, noncoding) sequences of DNA at the tips of chromosomes. As the cell repeatedly replicates itself, bits of the ends of the chromosome don’t copy, so the telomere part is giving the chromosomes leeway. Eventually, the telomere shortenings accumulate and will cut into actual coding DNA, leading to signs of aging. (Though I looked it up to double-check myself, and websites said that the bits that don’t copy don’t cut into the coding DNA—once it reaches the coding DNA, it makes the cell stop dividing. That sounds strange; I like what I learned, better.. hah)

      Wikipedia actually has a nice list of theories about aging here:
      http://en.wikipedia.org/wiki/Ageing#Biological_theories

    • #111646
      Hasansalhi
      Participant

      As everybody said, look up for Telomeres!
      Telomeres are sequences of the DNA that are added at the tips of chromosomes, and as a cell is passing through its division cycle, the DNA is replicated and the ends are shortened as a result of the END REPLICATION PROBLEM (read about this one, it will be useful to understand it). As these parts are shortened, at some point the ends will be almost near the coding DNA leading the cell to undergo apoptosis before the coding ends are cut as well!

      Telomerase is an enzyme that adds telomeres to the ends of chromosomes. The problem is that telomerase exists only in the cancerous cells (and I don’t actually understand why) and germ cells. Therefore, because it doesn’t exist in the normal somatic cells, these cells will die at some point, and well, as you know, not all body’s tissues can regenerate, and so those which die will progress to show some aging symptoms. Take a skeletal muscle tissue for example, it doesn’t regenerate and as its cells die by aging, muscle weakness will result!

    • #111852
      citroenboom
      Participant

      And what about my precious E. coli! They do not contain telomers 🙂

      They age because of damage by the environment, by dividing, DNA damage and that sort of things.

      In Groningen University (The Netherlands) is some nice research going on about this topic (as I understood)

    • #111871
      oncolytic
      Participant

      Look at this article, reliability theory of aging, it seems to be a little more fundamental than just causative theories like free radicals, etc.
      http://www.news-medical.net/news/2004/10/04/5271.aspx

    • #111872
      david23
      Participant
      quote citroenboom:

      And what about my precious E. coli! They do not contain telomers 🙂

      They age because of damage by the environment, by dividing, DNA damage and that sort of things.

      In Groningen University (The Netherlands) is some nice research going on about this topic (as I understood)

      Interesting thought, many years ago there were a few experiment about the regenerative abilities of bacteria cells. Basically they intentioned through heat, chemical, radiation etc etc induced damages to a few eColi colonies. examined them, and tagged a few cells/nucleotides, and cultured them for a few gens. Result, the later bacteria went on living normally. colonies grew.

    • #111874
      JackBean
      Participant

      Of course. Bacteria must survive. Technically every bacteria is old few billions of years.

    • #112085
      KileYe
      Participant

      I contend it is the metabolism that resulted in the aging of cells

    • #112230
      citroenboom
      Participant

      Still not all cells in a colony will grow. If I remember correctly from a presentation here some cells stop growing after a while and die. Or turn to ‘stand-by modus.

      A complete colony contains so much cells that some can survive, but most will not. It is a matter of selection.

    • #112314
      david23
      Participant
      quote KileYe:

      I contend it is the metabolism that resulted in the aging of cells

      Yeah metabolism is a huge factor.

    • #112433
      tmbirkhead
      Participant

      I see a lot of comments on here about shortening telomeres causing aging. The telomeres are a bit more tricky than that.

      Telomeres are indeed noncoding regions at the end of DNA that protect the rest of the DNA sort of like the hard part at the end of a shoe-string.

      When the telomeres get too short, the DNA can become exposed and damaged. However, if telomeres are kept forever long, the increased risk of cancer outweighs any good of keeping the cell alive. Cancerous cells are only dangerous because they can keep the telomeres long enough to continually divide and make copies of the mutant onco genes (this is simplified–I know).

      Further, I think it is certainly scientific to ask "Why" we age. The word, "Why", in this situation implies a cause and effect relationship. If such-in-such did or did not happen, then would the cells age.
      The real problem is defining what aging is on a cellular level. We know what age looks like on a macroscopic level and we understand age chronologically, but the fact is, some people die from age-related illnesses at much shorter times in their lives than others. We might say that they aged more rapidly.

      I did a research paper my sophomore year of college (last year) on the issue of aging and life rejuvenation theories.

      There is a lot of buzz about SENS theory. And although I like SENS, I cannot say whether or not it is valid (as a lot of highly trained bio-gerontologists disagree over this). However, reading about the SENS plan to reverse aging will give you the 7 currently accepted basic reasons for why we age.
      http://www.sens.org/sens-research/research-themes

      Let me know what you think

    • #112673
      jinx25
      Participant

      Interesting stuff on aging Tmbirkhead. Coq10, aceytyl carnitine, NADH stuff like that seems to be the way to go based on orthomolecular medicine (Linus Pauling, Abram Hoffer).

      http://www.youtube.com/watch?v=naweamfmhUI

      Both lived in to their 90’s and man they were still sharp as a razor as witnessed by these videos. Random interesting thing based on Peter Duesbergs book ‘Inventing the AIDS virus’ both him and Linus Pauling are the only 2 members of the national academy of science to have papers rejected for publishing (he says they could normally just skip the peer review and go straight to publishing) Dusberg for a paper on ‘HIV’ (and its lack of ever being proved to exist) and Linus Pauling for a paper on high dose Vit c and cancer.

    • #112792
      AstraSequi
      Participant

      Most or all of orthomolecular medicine is pseudoscience.

      Also, every scientist gets papers rejected, no matter what their standing is – it’s a normal part of the peer review process.

    • #112800
      jinx25
      Participant

      Pseudoscience? You mean the neodarwinian religion that pervades EVERY area of science? You might want to learn some basic biology before citing essential cofactors (vitamins/minerals) as ‘pseudoscience’.

    • #112804
      JackBean
      Participant

      jinx: And you should not bring your evolution issues to every discussion if you want to continue discussing.

    • #112808
      jinx25
      Participant

      He referenced pseudoscience yes i understand thank you.

    • #112809
      JackBean
      Participant

      He called orthomolecular medicine to be pseudoscience. Why don’t you mention astrology?

    • #112811
      jinx25
      Participant

      Yes and as i said learn some basic biochemistry. Astrology is not brainwashed into everyone on the planet at indoctrination camps (universities).

    • #112832
      AstraSequi
      Participant

      …And I didn’t say that "essential vitamins/cofactors" don’t exist or don’t play a role in the body, which is what you’re implying that I said. As I’m sure you know, orthomolecular medicine involves the consumption of those compounds to an extent that is, to the best of our knowledge, far above the levels biochemically necessary to carry out their functions.

Viewing 22 reply threads
  • You must be logged in to reply to this topic.