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No scar regeneration


fredreload

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I've read this article here and I come to the conclusion that, as long as scar does not develop, all tissues would heal. The only reason that tissues do not heal properly is because scar develops and stops the healing process. Therefore, if the scar does not develop, any tissue would undergoes the healing process of proliferation and regeneration. ClaronY, prove me wrong, this is speculation

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You seem to imply that scarring impedes healing. The logic here is backward. Scar tissue forms due to a fast healing process which causes overgrowth. I.e. without that, healing would be slow and potentially dangerous as the wound would need longer to close and thus invite infections.

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55 minutes ago, CharonY said:

You seem to imply that scarring impedes healing. The logic here is backward. Scar tissue forms due to a fast healing process which causes overgrowth. I.e. without that, healing would be slow and potentially dangerous as the wound would need longer to close and thus invite infections.

Well, it would be a growing blob of cells which still encases the wound if you look at lizard regeneration with(no scar tissues). The body with healthy immune system should be good enough to counter the infection. Lizard tissue regenerates without scarring right?

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20 minutes ago, fredreload said:

Well, it would be a growing blob of cells which still encases the wound if you look at lizard regeneration with(no scar tissues). The body with healthy immune system should be good enough to counter the infection. Lizard tissue regenerates without scarring right?

The glowing blob, as you put it, is the reason for the scarring. It is a predominantly a single cell type (IIRC) that initiates wound healing as well as the structures that result in the scar. From memory, this is mostly due to collagen deposited in a quick way to close the wound. Not all tissue in amphibians regenerate scar-free, it depends on species, type and location of wound and age of the individual. 

Also the adaptive immune system in humans and other mammals have been shown to play a role in preventing scar-free healing. I forgot the precise mechanisms, but I faintly recall that some interaction between macrophages.  Ultimately, I believe, it was speculated that the weak adaptive responses in salamanders allows their high regeneration abilities. In humans the ability is lost over time as the immune system becomes more restrictive to de-differentiated cells (like stem cells). One could speculate that this is protection against malign cell types that are also actively growing, such as cancers. But I am unclear on what the current state of research is.

Also, if you have an open wound, at some point the immune system is likely to fail. We can deal with it because our body closes them quickly and which is why larger wounds can lead to sepsis if not treated with antibiotics.

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1 hour ago, CharonY said:

The glowing blob, as you put it, is the reason for the scarring. It is a predominantly a single cell type (IIRC) that initiates wound healing as well as the structures that result in the scar. From memory, this is mostly due to collagen deposited in a quick way to close the wound. Not all tissue in amphibians regenerate scar-free, it depends on species, type and location of wound and age of the individual. 

Also the adaptive immune system in humans and other mammals have been shown to play a role in preventing scar-free healing. I forgot the precise mechanisms, but I faintly recall that some interaction between macrophages.  Ultimately, I believe, it was speculated that the weak adaptive responses in salamanders allows their high regeneration abilities. In humans the ability is lost over time as the immune system becomes more restrictive to de-differentiated cells (like stem cells). One could speculate that this is protection against malign cell types that are also actively growing, such as cancers. But I am unclear on what the current state of research is.

Also, if you have an open wound, at some point the immune system is likely to fail. We can deal with it because our body closes them quickly and which is why larger wounds can lead to sepsis if not treated with antibiotics.

Yes the lizard uses macrophages to create blastema(lizard stem cells) to close up the wound. Lizard does imperfect regeneration, but some organisms can perform perfect regeneration. Does the scar form during perfect regeneration? I wouldn't know.

But I could argue that stem cells of endothelial cells or other cell types do proliferate during human wound healing according to Wikipedia, that is mostly overlooked. And I wouldn't know if scar forming is a restrictive mechanism in wound healing. Such stem cells proliferation could close up the wound as well for us mammals. But this is pure speculation :P, clearly mammals are prone to getting injured. I wish I am like Hulk sometimes.

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On 11/5/2018 at 3:15 PM, fredreload said:

Yes the lizard uses macrophages to create blastema(lizard stem cells) to close up the wound. Lizard does imperfect regeneration, but some organisms can perform perfect regeneration. Does the scar form during perfect regeneration? I wouldn't know.

But I could argue that stem cells of endothelial cells or other cell types do proliferate during human wound healing according to Wikipedia, that is mostly overlooked. And I wouldn't know if scar forming is a restrictive mechanism in wound healing. Such stem cells proliferation could close up the wound as well for us mammals. But this is pure speculation :P, clearly mammals are prone to getting injured. I wish I am like Hulk sometimes.

Alright Charon, sorry about my limited understanding on this. My reasoning is focus on the adult stem cells lurking within the tissues and their abilities to repair and regenerate. It seems your reasoning is that without scars the wounded area's stem cells would go into an uncontrolled growth. This patterning system would likely be involved in another set of protein known as sonic hedgehog with the research conducted here. But as much as my claim is baseless without experiment there is nothing more I can add =/. Anyway, more research into adult stem cells could be used.

" Scientific interest in adult stem cells is centered on their ability to divide or self-renew indefinitely, and generate all the cell types of the organ from which they originate, potentially regenerating the entire organ from a few cells. " Wikipedia Adult stem cell

P.S. Fred wants to become a female, so he is looking into regeneration

Edited by fredreload
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On 11/5/2018 at 1:15 AM, fredreload said:

endothelial cells or other cell types do proliferate

I do not think that is overlooked, they are active in regular tissue healing and remodeling. However, in larger wounds the main actors are fibroblasts that deposit granulation tissue, which allows keratinocytes and other cells to invade and grow. The tissue becomes scarred since the matrix molecules, especially collagen are not deposited in the same way as during slow regenerative actions. Stem cells are a bit of  a different issue here,  what happens here is that involved cells de-differentiate. I.e. go from a differentiated dormant status into more active, proliferating, which also produces more of the matrix molecules (collectively termed extracellular matrix or ECM). Frankly, though the processes are very complex and I am only somewhat familiar with a limited set of pathways in a somewhat superficial way. So far, simple complete models are missing as folks find something new or correct existing knowledge on the molecular pathways on a regular basis. In fact looking at the contribution of a single cell type and the involved regulatory mechanisms in tissue remodeling can easily fill up a full career. The easiest and best understood systems tend to be in vitro aspects. E.g. differentiation of cells in controlled environment. Going from there to complex living tissue (which involves more cell types and far-reaching cell signaling) tends to get messy.

In my opinion, it will still take years until we are sufficiently confident in the various interactions so that we can start dumbing it down into a somewhat more digestible format that still somewhat accurate. As such, wiki pages will only be able to provide very descriptive accounts on the processes, which won't allow much extrapolation.

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