Adult stem cell vs embyronic stem cell

[fredreload]

What is the difference between the two? Yes these adult stem cells are found in the tissues, but how do these adult stem cells differ from embryonic stem cells?

 

P.S. The answer to regeneration and adult stem cells is in the liver tissue as liver is the only organ capable of regeneration

Edited November 6, 2018 by fredreload

[CharonY]

You can think of adult stem cells as slightly more specialized than embryonic ones. Depending on where they are located, somatic (or adult) stem cells are generally assumed to differentiate into certain cell types for local repairs and maintenance. Embryonic ones eventually are able to (and have to) differentiate in all possible cell types 

[fredreload]

12 minutes ago, CharonY said:

You can think of adult stem cells as slightly more specialized than embryonic ones. Depending on where they are located, somatic (or adult) stem cells are generally assumed to differentiate into certain cell types for local repairs and maintenance. Embryonic ones eventually are able to (and have to) differentiate in all possible cell types 

True, but what marks the difference between liver adult stem cells and adult stem cells from other tissues as liver is capable of complete regeneration? Is it because the liver adult stem cells are different or because its nearby cells ECM does not create scars during regeneration :D? Skin is also a tissue, but skin scars sometimes.

[CharonY]

No, the liver is not a terribly complex organ. Functional regeneration is possible by simply growing what is left. It also has only little to do with stem cells. Essentially it is the liver cells (hepatocytes) which are differentiated  (i.e. they do not become other cell types like stem cells) start growing. There is an influence of some stem cells, but they are already further differentiated and basically turn themselves into further hepatocytes or epithelial cells. Scars are, again irrelevant for its regeneration. the resulting liver mass can resume function but looks quite different from the original liver.

You seem to be hung up on scarring, it is really just deposition of fibrious tissue for a number of different reasons.

[fredreload]

15 hours ago, CharonY said:

No, the liver is not a terribly complex organ. Functional regeneration is possible by simply growing what is left. It also has only little to do with stem cells. Essentially it is the liver cells (hepatocytes) which are differentiated  (i.e. they do not become other cell types like stem cells) start growing. There is an influence of some stem cells, but they are already further differentiated and basically turn themselves into further hepatocytes or epithelial cells. Scars are, again irrelevant for its regeneration. the resulting liver mass can resume function but looks quite different from the original liver.

You seem to be hung up on scarring, it is really just deposition of fibrious tissue for a number of different reasons.

So you are saying that only liver adult stem cell is capable of regeneration in contrast to say neuronal adult stem cell. Well but where do these fibrous cells come from? I have a feeling they are also generated from the adult stem cells.

Is the scar tissue alive at all, I mean it is a cell type. It could be a compensation for the missing organ/tissue. Keep in mind liver does not scar, and from what I found they are as good as the original liver after regeneration.

P.S. If you can show me an example of a "wound site that healed without scar"(ex. like an amputated arm that healed without growing an arm back but has "no scar" on the amputated site, just muscle and bone tissue),  then I would deem your statement correct, that scar is not blocking the healthy tissue from regeneration

P.S. Liver regeneration->no scar/no fibrous tissue, spinal cord regeneration->scar/fibrous tissue. Why is that?

Edited November 7, 2018 by fredreload

[fredreload]

19 hours ago, CharonY said:

the resulting liver mass can resume function but looks quite different from the original liver.

It seems to me that all wounds are compensatory growth now.

[CharonY]

Nope in the liver it is not about stem cells but because of simple structures. Liver cells can restore function just by growing. Other organs can't do that as they require more complex structures. Connective and fibrous tissue are not cells but based on things cells produce to keep stuff together. Again you got things backwards but i really can't give a cell biology lecture just for you.

I can dig out some papers where folks try to minimize scarring, however concepts are somewhat advanced.

[fredreload]

On 11/7/2018 at 9:45 PM, CharonY said:

Nope in the liver it is not about stem cells but because of simple structures. Liver cells can restore function just by growing. Other organs can't do that as they require more complex structures. Connective and fibrous tissue are not cells but based on things cells produce to keep stuff together. Again you got things backwards but i really can't give a cell biology lecture just for you.

I can dig out some papers where folks try to minimize scarring, however concepts are somewhat advanced.

Thanks, I'll just read some article online. Still trying to find out if liver regeneration is perfect or not. It seems you are correct

 

Edited November 11, 2018 by fredreload

[fredreload]

On 2018/11/11 at 5:52 PM, fredreload said:

Thanks, I'll just read some article online. Still trying to find out if liver regeneration is perfect or not. It seems you are correct

So you need another patterning molecule to formulate the liver as it is regenerating, even adding that molecule alone to the compensatory organ should cause it to reform given that it already has the regenerating ability. I've been searching for that molecule and as far as I know it is called Sonic Hedgehog from the hedgehog pathway. But with the liver case it seems to be something presented only in the embryonic state

[fredreload]

23 hours ago, fredreload said:

So you need another patterning molecule to formulate the liver as it is regenerating, even adding that molecule alone to the compensatory organ should cause it to reform given that it already has the regenerating ability. I've been searching for that molecule and as far as I know it is called Sonic Hedgehog from the hedgehog pathway. But with the liver case it seems to be something presented only in the embryonic state

Apparently it's something that the adult stem cells lack and embryonic stem cell has.

Summary:

1. Both adult stem cells and embryonic stem cells proliferate to differentiate new tissue.

2. Adult stem cells sometimes produce scar, also know as fibrous cells/fibrous tissue.

3. Adult stem cells create compensatory growth, embryonic stem cells completely regenerate.

Edited November 15, 2018 by fredreload

[CharonY]

14 hours ago, fredreload said:

2. Adult stem cells sometimes produce scar, also know as fibrous cells/fibrous tissue.

That is wrong. Fibrous tissue is generally not consist of cells, but are part of the extracellular matrix (e.g. secreted collagen). For production of collagen and other fibers either stem cell type have to undergo a bit of differentiation. Fibrous tissues are also not scars per se they are structural and part of your normal body. Some types of scar tissue are characterized by a higher deposition than the normal amount of fibrous proteins and/ or different ordering so that the tissue looks different. That seems to be related to higher interference by the immune system to some degree. I.e. with a mature immune system, scarring increases.

[fredreload]

5 hours ago, CharonY said:

That is wrong. Fibrous tissue is generally not consist of cells, but are part of the extracellular matrix (e.g. secreted collagen). For production of collagen and other fibers either stem cell type have to undergo a bit of differentiation. Fibrous tissues are also not scars per se they are structural and part of your normal body. Some types of scar tissue are characterized by a higher deposition than the normal amount of fibrous proteins and/ or different ordering so that the tissue looks different. That seems to be related to higher interference by the immune system to some degree. I.e. with a mature immune system, scarring increases.

According to Wikipedia on scar. "The scarring is created by fibroblast proliferation,^[25] a process that begins with a reaction to the clot."

Fibroblast is a biological cell according to Wikipedia.

Liver also has immune pathogens from blood so I am ruling that out.

Edited November 16, 2018 by fredreload