How do the cells servive in the organs for transplant

[unbiased]

How are the organs like kidneys, heart etc stored before transplant? If frozen , doesn't the water turning into ice lead to bursting of cells?

 

[BrownTown]

Who said anything about freezing them?

 

[Mark R]

They're not frozen - just cooled, so that the metabolism is slowed right down.

This means that the organs are damaged much more slowly by the lack of blood flow, and can potentially last several hours. Freezing will destroy the organ due to ice crystals distrupting the cells and their internal structure.

 

[f95toli]

Browntown is correct, AFAIK organs are never frozen. They are cooled down to decrease the rate of metabolism in the cells but the temperature is always held well above zero.

 

[sao123]

would they not be better kept in a bowl of liquid which could cool & oxygenate them at the same time?

 

[Mark R]

[That'll teach me to assume that the way it's done here is the way it's always done]

Edit: Update - This has technique been tried using simple fluids for cold storage of organs for transplantation. The problems of oxygen solubility, and waste build-up are very much reduced at the lower temperature, making this a viable technique.

Artifical perfusion is sometimes used in the US, but is virtually unheard of in the UK. However, while some places may use this technqiue - there isn't really much good evidence that it's any better than just putting the organ in an ice box.

There are several large research projects on-going which are investigating whether perfusing the organ with fluid and oxygen is better than cold storage - because previous studies have not given clear results - a large number of transplant organs will need to be assessed and therfore the studies will need to run for another 5 to 10 years before the results can be finally analysed.

 

[Matthias99]

Originally posted by: Mark R
How would it oxygenate?

The organs would need to be perfused with some sort of oxygen containing fluid - currently there aren't any synthetic substances that can do the job, and trying to maintain a oxygenated circulation of blood is impractical.

I know I've seen video of lab rats 'underwater' in an oxygen-perfusing fluid, so I'm pretty sure there are some synthetic (or at least not-continually-pumped-out-of-a-living-human) materials to fit the bill. However, I don't know if that might cause further immune response problems when you transplant the organ.

I'm also not sure how much it would extend the amount of time you could keep an organ viable for transplant. Even if you can provide oxygen, you also need to remove waste products from the cells, and (eventually) they will also need nutrients like glucose, amino acids, etc.

Edit: Brief searching turned up some data on people doing experiments on animal hearts, and this document turned up some info on how they are kept alive. It certainly sounds like they have synthetic perfusion fluids that will work for at least a number of hours. But these are for research, not transplantation.

http://www.southalabama.edu/ishr/help/hearse/

 

[alpha88]

Just a side note about using oxygenated perfusion:

Cells are pretty resiliant.

When they loose their blood supply, they loose their energy supply (both oxygen for electron transport chain, and glucose/amino acids as the energy source).

With the loss of the energy supply, the ATP supply dwindles and then the ATP pumps aren't able to keep the ionic gradients correct and the cells swell. Cells can last quite a while like this, before they suffer irreversible damage.

In this state, getting oxygen is not always what the cells need - While oxygen is critical to ATP synthesis, it is very toxic to cells, so when a cell is stressed, the perfusion of oxygen can cause tremendous damage, because the cell's normal mechanisms of reducing the toxicitiy of oxygen aren't functional.

Thus, in order to significantly progress beyond just cooling cells and slowing their metabolism, we need to provide a good synthetic for the environment blood supplies (not just provide oxygen)

 

[Gibsons]

Freezing cells is easy.. it's organs that are hard. Human cells can easily be taken down to -80 and be expected to maintain viability. You just put them in the right antifreeze. Lots of problems getting this to work on something like a heart or a liver, though.

 

[CycloWizard]

There are a few solutions you can store organs in, depending on the organ and how long you're storing it for. The one that I recall off the top of my head is called 'Optisol GS', and has been shown to work well for cornea transplant and lens storage (which is helpful for us folks who use cadaver lenses for in vitro research). I'm not that familiar with other solutions, but I believe they generally contain proteins and physiologically concentrated saline to try to mimic in vivo conditions as closely as possible. Even with cold temperatures (usually 4°C is used, IIRC) and these solutions, storage time is very short - on the order of hours or days, depending on the organ and solution.

 

[artikk]

The concentration of solutes in the water solution of the cells will depress the freezing point. Therefore the cells will not freeze at nearly the same high T as regular water.

 

[Gigantopithecus]

Originally posted by: artikk
The concentration of solutes in the water solution of the cells will depress the freezing point. Therefore the cells will not freeze at nearly the same high T as regular water.

This is how wood frogs can survive sustained temps as low as 20 degrees F. They 'just' pack their cells with glucose - syrupy anti-freeze!

 

[Xdreamer]

freezer burned organs...... not so good.
(ice crystals are perforate cell membranes)
Chilled, not frozen. The medical equivillant to shaken, not stirred.

 

[wwswimming]

i was wondering the same thing about trees. for example, Sweden has lots of them, and it gets real cold there. normally if you have a vertical structure with thousands of vertical running tubes containing water, it would freeze, the wind would blow, it would shatter.

i can only conclude that the trees have some kind of natural antifreeze, or some other laws of physics/ chemistry keep the water in the trees from freezing.

 

[Karot]

I think that's called bark.

 

[Gibsons]

Originally posted by: wwswimming

i was wondering the same thing about trees. for example, Sweden has lots of them, and it gets real cold there. normally if you have a vertical structure with thousands of vertical running tubes containing water, it would freeze, the wind would blow, it would shatter.

i can only conclude that the trees have some kind of natural antifreeze, or some other laws of physics/ chemistry keep the water in the trees from freezing.

Don't know about those trees in particular, but many organisms have antifreeze proteins. Text

 

[Siddy]

Quick note, its the brain that dies with out oxygen quickly, other tissue can last a while.
The famous ninja pulling out a cut off heart thats still beating is actually true, but it wont beat in time like the movies, it would be all random.