Hacker News

blensor said 7 months ago:

I am not a medical expert or even remotely tied to that field but don't livers regrow to some extent? If this process could be extended even further wouldn't that mean we could regrow complete livers from partial donations pretty soon, making the whole "waiting for a donor" gamble obsolete?

Zemke said 7 months ago:


> The seven-day successful perfusion of poor-quality livers now allows for a wide range of strategies, e.g. repair of preexisting injury, cleaning of fat deposits in the liver or even regeneration of partial livers.

toomuchtodo said 7 months ago:

I assume that this might even assist in the growth of livers (extracellular matrix, liver and circulatory tissues) from stem cells.

war1025 said 7 months ago:

I think I read recently (don't know where, not looking it up) that the liver can regrow in the sense that it is made of lobes, and you can lose a lobe and the others will expand to restore full function.

But the lobes themselves don't regenerate, so it's not a thing that can be done more than a time or two.

Karlozkiller said 7 months ago:

No expert either, but afaik you can divide livers into thirds and they will regrow. So when you transplant a liver you take two thirds from the donor, I assume to give the recipient more liver to work with, but I don't know why. (spelling edit)

social_quotient said 7 months ago:

Yeah seems 25% is needed for regrow. That number seems interesting, almost like the body’s parity raid bit.


samstave said 7 months ago:

Funny to use “parity raid bit” on an SPOF organ such as is the liver.

Though, i have always been curious as to why the body only has one liver while having pairs of many other organs...

ASalazarMX said 7 months ago:

Adding to your question, why did the liver evolve to regenerate while other organs evolved to have spares? What makes it special?

akiselev said 7 months ago:

The liver is responsible for clearing out the majority of toxins and since many of them can cause cell death, the organ needs to be able to regenerate itself.

riversflow said 7 months ago:

I’m guessing it has something to do with the size of a liver. Organs that have spares are relatively small.

abakker said 7 months ago:

Lungs? They’re pretty big. My grandfather lived 60 years with only 1, and it stretched to fill most of his chest cavity.

trhway said 7 months ago:

a plastic surgery to build in Klingon like capabilities - take the piece of the liver like for transplant and transplant it into the other side of the body, and after some time for regrow the person would just have 2 full livers.

nkrisc said 7 months ago:

I'm not an expert but that won't stop me from guessing why!

Perhaps it would be far easier for the donor to regrow the majority of their own liver in their own body than it would be for the recipient, given the immune response and other factors that I would imagine complicate a transplant.

coder1001 said 7 months ago:

One great use of this could taking good parts of a cancer's patient's liver, regrowing the parts independently and then putting back the part that does not show any sign of cancer.

Not sure if one week will do it, but could be very viable when this tech is extended to more than a week.

Major advantage of reusing one's liver is the body would be less likely to reject it, hence relying less on immune suppression medications.

epmaybe said 7 months ago:

You hit the nail on the head. The tech needs to be extended more than a week without massive necrosis (which occurred in 4/10 livers in the study). I think that's something the authors of the Nature paper needed to have measured more of continuously (on top of the ATP production, BUN clearance, etc). Not sure which markers, to be honest, but there should be a decent range of apoptotic factors that can be sampled.

JulianMorrison said 7 months ago:

I wonder if they could just break the liver up into pieces, junk the 4/10 pieces that went oogy, keep and merge the rest?

cstejerean said 7 months ago:

Apparently at least 25% of the liver is needed to regenerate into a whole liver. So at most you could break it up into 4 pieces (or maybe 3 to be on the safe side).

stuartbman said 7 months ago:

Unfortunately most liver cancer is metastases from elsewhere, and once its in the liver, its likely to have spread to other organs as well, so this will not affect prognosis as you say until the cancer itself is treated.

esturk said 7 months ago:

You mean "most cancer in the liver" and not liver cancer. Liver cancer means HCC, as in the cancer originated from there.

stuartbman said 7 months ago:

I do, but the issue is also true for HCC, as the damage is often quite diffuse and less amenable to resection (DOI- not a liver doctor)

GGfpc said 7 months ago:

Can a person survive without a liver for 1 week?

toss1 said 7 months ago:

Based on the experiences of a friend & close family member & what the doctors said: when your liver stops functioning, you will have about six weeks to live. The prognosis schedule was pretty much spot-on in both cases,and the last week has much less useful consciousness. Since the first few weeks are not really debilitating, I'd wager that one week without a liver to re-implant a repaired organ should be a good plan.

golem14 said 7 months ago:

Out of curiosity: Amanita poison I thought mostly attacked the liver and leads to death in much less than 6 weeks (more like a few days, maybe a week). So I assume the 6 weeks means massive effort in the ER to stabilize the patient without liver, maybe some advanced blood filtering?

toss1 said 7 months ago:

Interesting discrepancy.

Both the ones I knew were in hospice and not a huge intervention for the six weeks, so not a tone of continuing intervention.

I'd guess that liver failure is maybe defined not as 100% failure, but failure to keep up with daily demand due to an external impairment such as cancer, and that this is just a typical curve of declining function until the body becomes too poisoned to survive.

Anybody with more detailed real bio/medical information?

husarcik said 7 months ago:

My medical education is congruent with your thoughts. Liver failure is defined as partial or complete loss of function. You're also right about the "too poisoned to survive" aka end-stage liver disease. People in this stage often die from too much toxin build up, infection, or bleeding. Your explanation is great.

toss1 said 7 months ago:

Thanks! very helpful.

UnFleshedOne said 7 months ago:

There might be necrosis of the liver involved, which adds a dump of toxins on top of non-functioning liver.

coder1001 said 7 months ago:

You wouldn't necessarily have to remove all of the liver. If you take say 50% of it, then the other 50% can regrow assuming a good chunk of it is still alive.

MetricT said 7 months ago:

No. My brother suffered acute liver failure following a diagnostic procedure to check his brain after having brain cancer surgery. He survived two weeks. And they were a horrible two weeks.

sizzle said 7 months ago:

I'm sorry for your loss. I hope no one has to go through this again with the advances in this new liver extending technology.

dghughes said 7 months ago:

I've always been amazed how livers can regenerate. But I recall reading the new liver is not a perfect copy there's some loss of function. I tried to find out what it was that I read but I can't find anything about it.

pkaye said 7 months ago:

I think it regenerates the bulk tissue but cannot reform the major arteries, veins and ducts.

greatpatton said 7 months ago:

I'm wondering how do they control pathogens, as from my understanding the perfusate is lacking white blood cell. This is not described in the Nature article.

However this kind of technologies open really a lot of new possibilities regarding organ transplantation, and even auto transplantation as describe at the end of the article.

epmaybe said 7 months ago:

The liver has reticuloendothelial tissues (along with spleen, lymph nodes) that do technically produce white blood cells. I'm not sure how much of this production is still active in adults.

pharke said 7 months ago:

I'm wondering if this will be a good test bed for keeping other organs alive outside the body. As far as I know, the liver is the most robust organ and so makes a natural starting point for this kind of work.

baxtr said 7 months ago:

The first question that popped into my mind is: does this work for brains too?

awinter-py said 7 months ago:

or as jim jarmusch would say, only livers left alive

piterdevries said 7 months ago:

What about a head?

mschuster91 said 7 months ago:

This one will probably take decades to get in a useful state.

For head (or other organ) artificial alive-keeping we still don't know enough about how they work - and in case of especially the head we don't have the adequate technology yet to properly reconnect the neurons.

It might be that we can do this sooner than keeping the full head alive though, given that there is way more investment in such research to help people with spinal injuries regain motor control.

BurningFrog said 7 months ago:

It seems like the inputs the head requires are pretty well defined.

Oxygenated, nutrition loaded blood mainly. But I'm sure that misses 8 unsolvable essentials...

Preserving sanity for the severed head is a whole other story.

mschuster91 said 7 months ago:

It's more complicated than "only" blood. The hormones and other signalling chemicals involved in the brain-body communication are not really figured out - we don't even know what hormonal balance is "normal" and treat mental illnesses such as depression and schizophrenia with a "shotgun" approach - shoot a lot of loads and see which one has an effect.

BurningFrog said 7 months ago:

There are also nerve "cables" to interface with.

aledalgrande said 7 months ago:

I've never heard about reconnecting severed nerves and have them function. Is that currently possible?

BurningFrog said 7 months ago:

Not that I know.

But it's at least an understandable and defined problem.

julsimon said 7 months ago:

Just add some fava beans and a nice Chianti.