What exactly is stopping people from re-growing entire limbs - it seems like we should be able to in good health ...
View: https://medium.com/a-microbiome-scientist-at-large/why-cant-we-regrow-limbs-32ba3c42e245
Soon after the wound has been sealed by a blood clot, however, salamanders develop a clump of cells beneath the surface, called a blastema. The cells that form this blastema tend to be from nearby — but they’re not normal skin cells or blood cells.
The cells that form the blastema are stem cells, cells that have not differentiated into a final cell type...
In the salamander, this ball of stem cells at the site of the wound multiplies and grows, with the stem cells converting into bone, muscle, and skin. A small, miniature version of the lost limb forms, which grows until it fits the rest of the animal.
The salamander determines how much of a limb to regrow (just the foot? The whole leg?) based on several factors, including the presence of connective tissue cells, called fibroblasts, and levels of retinoic acid, or vitamin A. Scientists have added extra retinoic acid at amputation sites and observed that the salamanders regrow extra-long arms, for example. "
Vitamin A helps salamanders grow extra large limbs - interesting ...
So then it seems like stem cells help the salamanders re-grow their limbs - theoretically it seems like the same could happen for people ?
How does the metabolic rate affect stem cell production ? I see that it regulates it but the only thing I can find is that a fasted state increases stem cell production ...
"This crosstalk between intermediary metabolism and epigenetics may in part account for how metabolic pathways can contribute to stem cell fate determination."
"These stem cells can theoretically be used as an inexhaustible source for cells. Scientists believed these cell products could be used to restore the functions of organs and treat diseases. However, regenerating cells and organs from a patient’s own cells and then returning them to that same patient turned out to be trickier than expected."
" Surprisingly, humans do regenerate some limited features and organs.
Consider liver transplants. Unlike a kidney transplant, the person who donates a liver doesn’t have to struggle for the rest of their life on half a liver; the organ regrows, although it doesn’t always reach the same capacity of function as before.
Lungs also regrow, to a limited extent. This is one of the reasons why it’s good to quit smoking; over the year after quitting, the lungs will regrow many of the air sacs and surface cells.
However, this doesn’t extend to limbs. Lop off an extremity, and it’s not coming back.
Why not?
There’s no certain answer, but there are several theories. "
No certain answer ? How can this be ? The theories don't seem to make much sense...
" One theory suggests that scar tissue is an adaptation — but one that prevents regeneration. Scar tissue forms quickly and helps seal over a wound, but it’s made of different materials than unmarred skin...
Another theory is that the cellular machinery that triggered regeneration was lost, possibly because the growth of cells can look a lot like cancer... This sounds like BS to me personally
We may also not have enough stem cells, or our cells have lost the capacity to naturally regress back to an undifferentiated state. Again, stem cells tend to pop up in cancerous tumors, so this loss isn’t necessarily a bad thing for us... once again this sounds like BS"
We can regrow cartilage and organ tissue - but can't regrow bones ? How can this be ? Can bones be re-grown with just a healthy metabolic rate ? The deer and lizards degrowing their bones seem to be in better metabolic health than most people - there doesn't seem to be anything stopping us from doing so ?
View: https://medium.com/a-microbiome-scientist-at-large/why-cant-we-regrow-limbs-32ba3c42e245
Soon after the wound has been sealed by a blood clot, however, salamanders develop a clump of cells beneath the surface, called a blastema. The cells that form this blastema tend to be from nearby — but they’re not normal skin cells or blood cells.
The cells that form the blastema are stem cells, cells that have not differentiated into a final cell type...
In the salamander, this ball of stem cells at the site of the wound multiplies and grows, with the stem cells converting into bone, muscle, and skin. A small, miniature version of the lost limb forms, which grows until it fits the rest of the animal.
The salamander determines how much of a limb to regrow (just the foot? The whole leg?) based on several factors, including the presence of connective tissue cells, called fibroblasts, and levels of retinoic acid, or vitamin A. Scientists have added extra retinoic acid at amputation sites and observed that the salamanders regrow extra-long arms, for example. "
Vitamin A helps salamanders grow extra large limbs - interesting ...
So then it seems like stem cells help the salamanders re-grow their limbs - theoretically it seems like the same could happen for people ?
How does the metabolic rate affect stem cell production ? I see that it regulates it but the only thing I can find is that a fasted state increases stem cell production ...
"This crosstalk between intermediary metabolism and epigenetics may in part account for how metabolic pathways can contribute to stem cell fate determination."
Stem cells could regenerate organs – but only if the body won't reject them
The idea behind regenerative medicine is that the patient is both the donor and recipient of healthy tissue grown from stem cells. But sometimes the transplanted cells are rejected. Now we know why.
theconversation.com
"These stem cells can theoretically be used as an inexhaustible source for cells. Scientists believed these cell products could be used to restore the functions of organs and treat diseases. However, regenerating cells and organs from a patient’s own cells and then returning them to that same patient turned out to be trickier than expected."
" Surprisingly, humans do regenerate some limited features and organs.
Consider liver transplants. Unlike a kidney transplant, the person who donates a liver doesn’t have to struggle for the rest of their life on half a liver; the organ regrows, although it doesn’t always reach the same capacity of function as before.
Lungs also regrow, to a limited extent. This is one of the reasons why it’s good to quit smoking; over the year after quitting, the lungs will regrow many of the air sacs and surface cells.
However, this doesn’t extend to limbs. Lop off an extremity, and it’s not coming back.
Why not?
There’s no certain answer, but there are several theories. "
No certain answer ? How can this be ? The theories don't seem to make much sense...
" One theory suggests that scar tissue is an adaptation — but one that prevents regeneration. Scar tissue forms quickly and helps seal over a wound, but it’s made of different materials than unmarred skin...
Another theory is that the cellular machinery that triggered regeneration was lost, possibly because the growth of cells can look a lot like cancer... This sounds like BS to me personally
We may also not have enough stem cells, or our cells have lost the capacity to naturally regress back to an undifferentiated state. Again, stem cells tend to pop up in cancerous tumors, so this loss isn’t necessarily a bad thing for us... once again this sounds like BS"
Humans Have A 'salamander-like' Ability To Regrow Cartilage
The title says it all, but the study authors make the unfortunate/handicapped conclusion that while we may very well be able to regrow cartilage, we cannot regrow limbs. Well, multiple animal studies I posted in the last beg to disagree and point to both high metabolism and progesterone as...
raypeatforum.com
We can regrow cartilage and organ tissue - but can't regrow bones ? How can this be ? Can bones be re-grown with just a healthy metabolic rate ? The deer and lizards degrowing their bones seem to be in better metabolic health than most people - there doesn't seem to be anything stopping us from doing so ?
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