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retinoids, AHA's, telomere length & the hayflic limit


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#1 ajnast4r

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Posted 12 January 2008 - 09:31 PM


"The main benefits of alpha hydroxy acids come from its ability to exfoliate skin. Removal of the outermost layer of the skin stimulates the cells in lower layers to grow and divide, causing the skin to thicken and thus diminishing visible signs of aging. The more you exfoliate, the more cell divisions you have occurring in the lower skin layers. There is one problem though. Normal human cells cannot divide indefinitely. Fibroblasts (a key type of cells in the skin) will divide about fifty times and then enter a so-called stage of senescence. This is a state in which cell division becomes sluggish, inefficient and unresponsive to various signals from the body and unable to divide. This is similar to how a plant will slow its leaf and bloom production at the end of its growth cycle. Skin with many senescent cells is usually fragile, blotchy and easily wrinkled. This limit of about fifty cell divisions is called the Hayflick limit (after its discoverer, Dr. Leonard Hayflick).


http://en.wikipedia..../Hayflick_limit



this would imply that for a while, retinoids/aha's would give us younger looking/better skin but after a decade or two we may hit a 'telomere wall' where our skin cells would not be able to divide at the normal rate... dooming us to prematurely and permanently aged skin. for this to be true wouldnt we need to only have a limited number of skin cells to begin with? do we only have a limited about of skin cells each limited to 50+ divisions, or do we have a never ending supply of skin cells limited to 50+ divisions?


discuss

Edited by ajnast4r, 12 January 2008 - 09:33 PM.


#2 Mind

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Posted 12 January 2008 - 11:36 PM

Just thinking about the skin of older people. It certainly gets rather blotchy with most people when they reach the 80s and 90s and does not work as well (sweating, thermal management, etc...). Is this because of the hayflick limit as well?

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#3 luminous

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Posted 13 January 2008 - 12:17 AM

"The main benefits of alpha hydroxy acids come from its ability to exfoliate skin. Removal of the outermost layer of the skin stimulates the cells in lower layers to grow and divide, causing the skin to thicken and thus diminishing visible signs of aging. The more you exfoliate, the more cell divisions you have occurring in the lower skin layers. There is one problem though. Normal human cells cannot divide indefinitely. Fibroblasts (a key type of cells in the skin) will divide about fifty times and then enter a so-called stage of senescence. This is a state in which cell division becomes sluggish, inefficient and unresponsive to various signals from the body and unable to divide. This is similar to how a plant will slow its leaf and bloom production at the end of its growth cycle. Skin with many senescent cells is usually fragile, blotchy and easily wrinkled. This limit of about fifty cell divisions is called the Hayflick limit (after its discoverer, Dr. Leonard Hayflick).


http://en.wikipedia..../Hayflick_limit



this would imply that for a while, retinoids/aha's would give us younger looking/better skin but after a decade or two we may hit a 'telomere wall' where our skin cells would not be able to divide at the normal rate... dooming us to prematurely and permanently aged skin. for this to be true wouldnt we need to only have a limited number of skin cells to begin with? do we only have a limited about of skin cells each limited to 50+ divisions, or do we have a never ending supply of skin cells limited to 50+ divisions?


discuss

FWIW, Fredrik addressed the Haflick limit in an earlier thread, saying that real skin doesn't behave the same way as skin cells in a petri dish. See post #78:
http://www.imminst.o...mp;#entry191942

#4 Mind

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Posted 13 January 2008 - 12:36 AM

According to that post by Frederik, losing skin cells actually increases the health of your skin by getting rid of pre-cancerous lesions.

#5 ajnast4r

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Posted 13 January 2008 - 01:22 AM

FWIW, Fredrik addressed the Haflick limit in an earlier thread, saying that real skin doesn't behave the same way as skin cells in a petri dish. See post #78:
http://www.imminst.o...mp;#entry191942


excellent, that makes me very happy :D

that thread is a great read btw

#6 mitkat

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Posted 13 January 2008 - 08:06 AM

Fredrik is a true skin guru.

Ajnast4r thank you for bringing up a topic that I hadn't even really thought about, to be honest.

FWIW, Fredrik addressed the Haflick limit in an earlier thread, saying that real skin doesn't behave the same way as skin cells in a petri dish. See post #78:
http://www.imminst.o...mp;#entry191942


excellent, that makes me very happy :D

that thread is a great read btw



#7 frederickson

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Posted 14 January 2008 - 04:33 PM

According to that post by Frederik, losing skin cells actually increases the health of your skin by getting rid of pre-cancerous lesions.


DOH!!! disregard prior post about hayflick limit!

Edited by frederickson, 14 January 2008 - 05:01 PM.


#8 caston

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Posted 09 February 2008 - 03:04 AM

this would imply that for a while, retinoids/aha's would give us younger looking/better skin but after a decade or two we may hit a 'telomere wall' where our skin cells would not be able to divide at the normal rate... dooming us to prematurely and permanently aged skin. for this to be true wouldnt we need to only have a limited number of skin cells to begin with? do we only have a limited about of skin cells each limited to 50+ divisions, or do we have a never ending supply of skin cells limited to 50+ divisions?


discuss


So I wonder what would happen if you used a retinoid in combination with something like TA-65 e.g a telomerase inducer.

#9 donjoe

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Posted 09 February 2008 - 08:05 AM

So I wonder what would happen if you used a retinoid in combination with something like TA-65 e.g a telomerase inducer.

Hmm... I'd expect that to make healthy cells and cancer cells longer-lived (unless there's research that says otherwise). For now, I'd rather let the body regulate stem cell multiplication on its own, as it seems it can work just fine for at least 30 years, and even if that's not enough, I expect more options to be available 30 years from now, given all the stem cell research that's being done.

Edited by donjoe, 09 February 2008 - 08:06 AM.


#10 caston

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Posted 09 February 2008 - 12:20 PM

So I wonder what would happen if you used a retinoid in combination with something like TA-65 e.g a telomerase inducer.

Hmm... I'd expect that to make healthy cells and cancer cells longer-lived (unless there's research that says otherwise). For now, I'd rather let the body regulate stem cell multiplication on its own, as it seems it can work just fine for at least 30 years, and even if that's not enough, I expect more options to be available 30 years from now, given all the stem cell research that's being done.



I don't think anyone knows what it would do and to be clear I am not advocating that anyone try it on anything other than invitro cells or an animal model but it has been suggested before that telomerease inducers can actually help prevent cancer.

Edited by caston, 09 February 2008 - 02:43 PM.


#11 Eva Victoria

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Posted 17 February 2008 - 10:40 AM

Very interesting question ;)

Would like to add some things here:
1) our skin (and all organs in the body) are made to last decades!
2) if you follow the instructions of a dermatologist and don't overuse AHAs, Retinoids you`ll strengthen your skin. Of course with the usage of these chemical enhancers one should always keep in mind that a high UV protection is required since your natural protection is "minimized" (the dead-skin cells in the Horny layer, which provide natural protection at least against some UV-damage, are slugged off effectively by AHA, or Retinoids).
So the conclusion is that lack of sunscreen use is what will age one when on AHAs, Retinoids.

#12 donjoe

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Posted 18 February 2008 - 06:34 PM

... I expect more options to be available 30 years from now, given all the stem cell research that's being done.

Annd nine days later, what do I find out?

UCLA stem cell scientists have reprogrammed human skin cells into cells with the same unlimited properties as embryonic stem cells without using embryos or eggs.

Led by scientists Kathrin Plath and William Lowry, UCLA researchers used genetic alteration to turn back the clock on human skin cells and create cells that are nearly identical to human embryonic stem cells, which have the ability to become every cell type found in the human body. Four regulator genes were used to create the cells, called induced pluripotent stem cells or iPS cells.

Sweet! ;)

Edited by donjoe, 18 February 2008 - 06:34 PM.





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