5 replies to this topic

[Sable]

It's my understanding that somatic cells only divide so many times before they become unable to continue the cycle, and require replacement via stem cell differentiation. Is it not also believed that stem cells become more dysfunctional over many cycles, decreasing in their ability to replace damaged cells? And hence, might exfoliation and similar processes that put extra demand on cells lead over time to a higher accumulation of damaged cells in the body than would otherwise be present? 

[mustardseed41]

http://www.longecity...e-3#entry191942

[Heyman]

It's my understanding that somatic cells only divide so many times before they become unable to continue the cycle, and require replacement via stem cell differentiation. Is it not also believed that stem cells become more dysfunctional over many cycles, decreasing in their ability to replace damaged cells? And hence, might exfoliation and similar processes that put extra demand on cells lead over time to a higher accumulation of damaged cells in the body than would otherwise be present? 

 

The hayflick limit doesn't apply to skin, as there are stem cells producing it. You will never run out of skin. Did you ever see an old person that lost his skin and it didnt get replaced?

[Sable]

http://www.longecity...e-3#entry191942

 

That post refers to fibroblasts, whereas I was thinking more along the lines of keratinocytes. I may be wrong, but I'm under the impression that as keratinocytes are sloughed off, the epidermal stem cells are put under demand to replace them, and exfoliation obviously creates additional demand. 

 

 

It's my understanding that somatic cells only divide so many times before they become unable to continue the cycle, and require replacement via stem cell differentiation. Is it not also believed that stem cells become more dysfunctional over many cycles, decreasing in their ability to replace damaged cells? And hence, might exfoliation and similar processes that put extra demand on cells lead over time to a higher accumulation of damaged cells in the body than would otherwise be present? 

 

The hayflick limit doesn't apply to skin, as there are stem cells producing it. You will never run out of skin. Did you ever see an old person that lost his skin and it didnt get replaced?

 

 

I wasn't implying that one would run out of skin. My implication was that stem cells eventually become sluggish -- something that exfoliation could possibly accelerate by forcing them to replicate more frequently -- and skin as a result ends up comprising a higher ratio of damaged to healthy cells. 

Edited by Sable, 03 October 2014 - 10:03 PM.

[gt35r]

Sable,

 

I understand what you are saying.

 

Stems cells are generally lost over time and due to reproduction. Turnover of the epidermis is due to stem cells along the basal membrane of status basale. 

 

It is a valid concern but for some reason it is not something that is witnessed or recorded. Sometimes stem cells are lost from under use, some times they are lost from over use, and sometimes they are not lost at any great rate. IT may be possible that exfoliation may improve the retention of stem cells in the basal layer over a period of time.

 

 

[JohnD60]

It's my understanding that somatic cells only divide so many times before they become unable to continue the cycle, and require replacement via stem cell differentiation. Is it not also believed that stem cells become more dysfunctional over many cycles, decreasing in their ability to replace damaged cells? And hence, might exfoliation and similar processes that put extra demand on cells lead over time to a higher accumulation of damaged cells in the body than would otherwise be present? 

 

A woman that does microderms told me this same thing once. I believe it to be a myth for the reasons listed in the post linked to earlier in the thread.