_googlefanatic_ t1_ixl4s5m wrote
Reply to comment by iayork in If freezing tissue generally damages the cells, how are we able to freeze human eggs and embryos for birthing later? by badblackguy
Why can tissues be not frozen and 'stored' ?
Ishana92 t1_ixlj0dr wrote
You will lose some cells after thawing. The bigger the tissue, the larger the damage. And for tissue every bit of damage has an impact.
If you take cell culture, its basically asuspension of independent cells. You can lose 50% of them and the rest will repopulate everything. But if you lose 50% of cells in your tissue that tisdue is no longer functional and wont survive.
Terr_ t1_ixlkxhy wrote
Another metaphor:
Suppose you have a thousand planks of wood in nice stacks. You can store them and still be okay if a random 10% become rotted and must be thrown out.
Now imagine you store a house made out of a thousand planks of wood, and again 10% of it rots. It might become dangerously weak, and it will be very expensive to check and replace the bad parts.
_googlefanatic_ t1_ixlmglt wrote
But I don't understand , why does a few cells destroyed in a tissue affect the tissue , the cells can re divide , right? If not then why so ?
wedontlikespaces t1_ixlnbah wrote
Because when they're independent cells they are independent but when they're in a tissue they're part of a larger structure, so if that larger structure is damaged the whole tissue becomes nonviable.
If 10% of a heart dies, then the entire heart no longer works.
Going back to the house example, if a structural support beam is one of the 10% of wooden beams that rots, then the whole house is going to fall down. It's not a perfect analogy because obviously there's some bits of wood which are more important than others, but you get the idea.
Terr_ t1_ixlnrjg wrote
Many of the cells in your body have stopped dividing, they've settled into specialized roles and positions and will not "fill in the gaps" by duplicating to replace missing neighbors. The shape of everything else around them and the signals from their neighbors cause them to act in certain narrow ways. When they don't do that and start dividing again, that's often cancer.
New cells are usually generated from deeper spots, from special cells with the job of just churning out certain kinds of gradual replacements.
So if you choose a random zone of tissue and kill some cells in it, those gaps or weaknesses may persist in that area until everything around it is pushed out and replaced by the march of fresh cells from further in.
If you damage one of those special zones where new cells are still being made, the damage could be permanent, like getting a scar on your skin that lasts even when almost all of the cells have been replaced over time.
_googlefanatic_ t1_ixlu4ze wrote
Got it , but It should be rare right ? Like when we damage the exact location ....
Ishana92 t1_ixm22tp wrote
If you had time to repair all the damage it would be fine, probably. But those cells that died are releasing all sorts of messages to neighbouring cells. It's not just that they died and now there is a hole to fill, it's that now there is a hole and neighbouring cells are also freaking out and not doing their job. And then if you have living organism the immune response is going to kick in and just go crazy at site that is damaged. You get the whole cascade when cells are all dependent.
TEW20 t1_ixmthod wrote
Not necessarily, some structures never regenerate and scar tissue forms where the damage happened, so that part of the tissue never recovers it's function. That's why damage to some organs cannot be repaired.
[deleted] t1_ixlpoiw wrote
[removed]
[deleted] t1_ixlt6z5 wrote
[deleted]
_googlefanatic_ t1_ixlmgyn wrote
But I don't understand , why does a few cells destroyed in a tissue affect the tissue , the cells can re divide , right? If not then why so ?
Ishana92 t1_ixm2pue wrote
Its because of complexity. Lets say you freeze a kidney then you thaw it and try to reassimilate it. Cells thst died will severely disrupt its function. In many cases replacing those cells is a slow and gradual process and not something that can be done quickly (whereas in cell culture you usually only have one cell type and they are functionally all the same).
Then you have the tissue and system response. Cells that die during freezing die messy. They burst and that releases toxins into your blood stream. Then immune cells come via blood and start inflammation which further damages the tissue. In the end you have a string of failures.
GreatBayTemple t1_ixne205 wrote
So you need nanobots that can connect to cell tissue and each other, mimic the cell structure and send signals to neighboring cells to function as usual while cells are cultured into place on the organ? Like a special film?
_googlefanatic_ t1_ixlmcka wrote
So you mean that If we lose 50% of individual cells , it doesn't matter as we can mitosise them. But if we lose 50% cells of a tissue , the tissue may stop working?
CMxFuZioNz t1_ixmr0w7 wrote
No. If you freeze 50 eggs and 25 of the eggs are damaged by freezing/thawing that doesn't affect the other 25 eggs which weren't damaged.
If you freeze a heart and half of it is damaged, the whole thing will no longer work when you put it in someone.
[deleted] t1_ixm25e5 wrote
[removed]
Viewing a single comment thread. View all comments