Why is the liver so weirdly regenerative?

(dynomight.substack.com)

66 points | by jbotz 3 hours ago

9 comments

  • vconnor 45 minutes ago
    The punishment for Prometheus stealing fire from the Gods and gifting it to humanity, was to be chained to a rock and having an eagle feed on his liver which would regrow the next day.
    • bheadmaster 26 minutes ago
      For what it's worth, Prometheus was a Titan, and Titan was immortal, so his liver regrowing the next day wasn't really that special. If eagle fed on his heart, or lungs, they would've regrown too.

      The Greeks chose liver because it symbolized the defiance Prometheus had against gods.

      • bryanrasmussen 10 minutes ago
        There's really no knowing why the Greeks chose liver, or some specific Greek chose liver.

        It could have been because the liver was regenerative and they were using the titan with the regenerating liver as another reference to humanity, or it could have been as someone pointed out because predators like to eat the liver first, or it could have been that you can take damage to the liver and live for hours afterwards in agony whereas the same amount of damage to the heart or lungs is apt to cause death to come much quicker.

        Perhaps there are undiscovered variants out there were the eagle or a serpent or some other animal attacks his genitals, or his eyes.

        But at any rate the Eagle ate his liver, it means nothing in particular, and at the same time it means every particular interpretation we can place on it.

        • bheadmaster 3 minutes ago
          Whatever the actual reason for choosing the liver was, we can be certain it wasn't its regenerative property, since such proprerty was unknown to the Greeks at the time.
      • seizethecheese 25 minutes ago
        Why would liver signal defiance?
        • Sleaker 14 minutes ago
          It was the believed area of emotion, passion and 'soul'. I think western/modern religion has morphed from the liver to the heart essentially.
        • jephs 13 minutes ago
          There are a bunch of Japanese words (including a several loanwords from Chinese) that use the liver / gallbladder metaphorically for courage. Both derive from associations between the humours and personality / behavior. I have no idea, however, why both Eastern and Western naive psychology associate gall with, well, gall.
        • bheadmaster 12 minutes ago
          I phrased it awkwardly. Simply put, in Ancient Greece, liver was something like heart in modern society. It was the seat of human emotions.

          So by destroying Prometheus' liver, Zeus attempted to destroy his human emotions, including his pride and defiance against gods.

        • Bluestein 18 minutes ago
          Humors perhaps. Not my area, so I do not recall the correspondence ...
      • bell-cot 17 minutes ago
        I'm thinking the Greeks chose liver because it is the first thing that many predators will eat from a kill - large, more nutrient-dense than almost any other tissue, and relatively quick to access.
  • Aeolun 33 minutes ago
    I feel like this is obvious. Eventually dying of all the weird body failures doesn’t inhibit your ability to procreate, but if you cannot survive alcohol or other various poisons you’ll never make it to a fertile age.
    • nomel 13 minutes ago
      Picking the wrong berry from a bush isn't so difficult. Ask me how I know. And, for my second encounter, don't think because you see an animal eating it, it's safe!
  • amluto 2 hours ago
    The lack of heart cancer might be more complex than the OP imagines:

    https://www.science.org/content/blog-post/no-heart-cancer-th...

    • jaggederest 44 minutes ago
      Other animals do get heart cancer, which is fascinating. It's still very uncommon compared to other cancers, but not virtually absent as it is in people.
  • warumdarum 15 minutes ago
    Because alcoholism forces hunter gatherer cultures into settlements, which are the next stage of civilization and reward those doing that choice?
  • schnuri 2 hours ago
    I am in awe about how wonderfully engineered by evolution the body is. E.g., what we are able to do with it and how it heals itself when we have an injury. Sure, many people would not live long without external intervention, but many others would. I still want to see the robot that can survive 80 active years without maintenance.
    • dgunay 59 minutes ago
      Well, we do at least have to eat enough food and sleep ~1/3rd of our lives. That's kinda maintenance
      • yhjc2692 4 minutes ago
        quite the delightful maintenance too
      • micromacrofoot 46 minutes ago
        that's absolutely maintenance, without it you have a total system failure in a week
    • ericmay 49 minutes ago
      When you watch those sci-fi shows and folks have nanobots implanted in them that heal wounds really fast or do other cool things I can't help but think in many ways we already have that technology we just need it to do more, faster as our brains and ability to create things have outpaced the rate of evolutionary change.
    • RobotToaster 59 minutes ago
      Humans don't last long without topping up their fluids and consumables.
    • markyc 1 hour ago
      no you don't
    • chistev 1 hour ago
      The human body can't survive 80 active years without maintainance. They take drugs, they see the doctor, etc.
      • CookieCrisp 1 hour ago
        What did people do 500 years ago?
        • EduardoBautista 59 minutes ago
          Die as a child at alarming rates
          • lukan 53 minutes ago
            But those who did not, got quite old without ever seeing a doctor.

            (If we are talking about hunter gatherers, not poor exploited peasants)

            • steve_adams_86 13 minutes ago
              Humans have assisted each other medically, supported injured and disabled tribe members, and sought out medicinal herbs since long before history was written. I'm not sure how you'd delineate between modern health care and when humans never had some notion of health care and/or support when bodies enter failure modes. We don't survive well without a lot of assistance and care, and living long lives required plenty of bodily maintenance regardless of how fortunate and healthy we were.
            • 1attice 39 minutes ago
              Citation required
              • Fezzik 15 minutes ago
                Gurven, Michael & Hillard Kaplan (2007). “Longevity Among Hunter-Gatherers: A Cross-Cultural Examination.” Population and Development Review, 33(2), 321–365

                If you made it past age 5 as a hunter-gatherer you’d likely live to 50-60 years of age.

                • 1attice 9 minutes ago
                  Interesting. Yet as someone approaching the first of those two last numbers, I would say that that isn't very old at all
                  • Fezzik 0 minutes ago
                    It’s also worth noting that, while this is (I think) likely the most cited paper on the topic, all the observed societies are from the 20th century. So we can’t necessarily extrapolate from that that hunter-gatherers 300,000 years ago fared the same.
  • agumonkey 42 minutes ago
    Anybody on HN knows platforms to discuss this ?
    • gchamonlive 38 minutes ago
      This is a platform and we are discussing this, which means such a platform isn't enough for what you need. Not judging, actually I've felt a degradation in engagement quality as of late, maybe it's personal bias, but the discussions seem more shallow or aggressive.

      In any case, what would you expect from such a platform? That would help with recomendations.

  • card_zero 1 hour ago
    > Evolution decided the good outweighed the bad, and I expect that evolution was right.

    We can expect evolution to do the right thing for the genes. Not for us.

    • cortesoft 1 hour ago
      I get its just a framework to understand what is happening, but I always hate the phrasing of describing a 'decision' to a process like evolution. There are no decisions being made in the process, just a series of outcomes that lead in a direction
      • someonebaggy 48 minutes ago
        Evolution is literally just the observation that there are lots of things that self-replicate.

        That's it. That's the entire thing. Plus some nuance about things that self-replicate faster than other things...

        It occurs at all levels. Amyloid protein in Alzheimer's patients is self-replicating. So are cells. So are individual parts of cells. Sometimes things replicate by being parts of a larger thing that replicates, sometimes they don't. It's all one big chaotic tangled mess with no particular purpose or design. Human cells evolve, so do humans, so do human societies. So do rocks.

        • dekhn 4 minutes ago
          No, evolution is not an observation that there are things that replicate. Darwin's view, which has survived mostly intact, is that there is replication with variation and that more fit individuals replicate at a higher rate ("survival of the fittest" isn't a correct description; plenty of less fit individuals do replicate, but they contribute very little to the population genetics in the long run)

          And amyloid protein doesn't self-replicate. An instance of the misfolded form causes other folded proteins of the same type to transition to the misfolded form. It's a form of catalysis, not self-replication.

        • cwillu 45 minutes ago
          Rocko can't have kids, because Rocko is just a stupid rock.
          • card_zero 4 minutes ago
            Possibly a reference to A.G. Cairns-Smith, who speculated about evolving clay crystals. (They can sit in a stream and accumulate minerals, and reproduce that way.)
      • card_zero 7 minutes ago
        Oh, fair point, I did the pathetic fallacy (too). Beneficial thing, then.
      • CookieCrisp 56 minutes ago
        Indeed, I’ve heard so many people misunderstand it because of this type of wording. Like there is still some plan and series of steps we’re following - which really misses the whole point and why it’s worth knowing in the first place
  • bbor 1 hour ago

       I greatly resent having to be a biological organism and subject to all the poor engineering and design decisions that entails.
    
    The first word of that sentence implies its absurdity quite beautifully. She resents, therefor she is.

    And then this:

      Brains. After you reach adulthood, neurons don’t divide. If some of your neurons die—which happens every day—then they’re gone. If you get a brain injury, the other neurons will try to “learn around” the injury, but the neurons themselves are never replaced.
    
    We need more neuroscience in schools! This summary is technically correct ofc, but to imply that the brain is missing some obviously-better option is absurd. We're meat that thinks, y'all; it's far from crap.
    • someonebaggy 46 minutes ago
      IIRC the slow loss of neurons is more than balanced by the additional fine-tuning - unless you get dementia, if course.

      Loss of neurons isn't disastrous as long as it's not too many. Babies are born with several times more neurons than children have, and spend a few months letting all the useless ones die. Apparently it's better to start with a random tangle and prune it to shape (like cutting a box hedge) than to make a hedge grow in a box shape to begin with.

      And IIRC brains can grow more neurons under some circumstances (certain drugs?) - they just normally don't.

      • rzzzt 32 minutes ago
        "While questions remain regarding the precise extent, rate, and functional relevance of adult neurogenesis in the human brain, as well as important methodological considerations, multiple independent approaches now converge in support of its persistence throughout adulthood."

        https://www.sciencedirect.com/science/article/pii/S193459092...

    • dekhn 20 minutes ago
      the claim isn't complete, either. Recent research has demonstrated adult neurogenesis (growth of new cells that originate from neural stem cells).
    • done_lurking 36 minutes ago
      Why is it absurd to say that the human brain could be better? That seems obviously true to me.
  • dekhn 2 hours ago
    [flagged]
    • dang 1 hour ago
      "Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something."

      https://news.ycombinator.com/newsguidelines.html

    • rwmj 2 hours ago
      I can't judge if you are correct or not. It would be more convincing if you could name some of the problems. Since the article is "garbage", there should be lots of things wrong to choose from.
    • haskellandchill 2 hours ago
      I agree. Very shallow "sources" and no qualifications to be speaking on a medical topic. There is a role for pop science to disseminate knowledge but this is pure speculation.
      • dang 43 minutes ago
        There's nothing wrong with speculation on HN. Speculation is intimate with curiosity, and curiosity, not correctness, is the guiding value of this site.

        It may seem odd to demote correctness in that way, but it doesn't mean we value incorrectness. Correctness is good, just not at the top of the hierarchy. Curiosity—specifically, intellectual curiosity—is what we're optimizing for (https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor...).

        We value the freedom to meander around topics in a curious way. Of course this means following paths that turn out to be wrong [1], but that is how new things are learned, and it's a good way to spend time. People are allowed to be wrong on HN [2]. It's part of figuring out what's true. Truth is crucial, but one ought not to squeeze the throat of speculation so tightly that wrong things aren't allowed to be said, or fun to be had.

        [1] not saying the OP is right or wrong - I have no idea about that - but the article looks like the fun kind of meandering speculation that has a good place here.

        [2] https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...

        https://news.ycombinator.com/item?id=11655206

        • warumdarum 12 minutes ago
          What is a new hypothesis other than a conspiracy of circumstances making better sense..