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posted by martyb on Thursday November 08 2018, @11:24PM   Printer-friendly
from the unlimited-frogs-legs-for-dinner dept.

Scientists Got Adult Frogs to Regrow Limbs. It's a Step Toward Human 'Regeneration'

Millions of people live with amputated limbs that are gone forever. But that might not be the case in the future. For the first time, scientists have shown that adult frogs can regrow amputated legs. They say the approach can work in humans, too. "There is no reason that human bodies can't regenerate," said Tufts University biologist Michael Levin, who led the new research. "This is the first proof-of-principle of a roadmap for regenerative therapy in human medicine, well beyond limbs," he added. "Many problems — from birth defects to traumatic injury, aging and even cancer — could be solved if we understood how to induce organs to regrow in place."

Ultimately, that's what Levin and his research team at Tufts University in Medford, Massachusetts, want to figure out: how cells cooperate to build a complex three-dimensional organ and "stop exactly when it's done." But first, the scientists needed to try to reproduce organ growth in animals that don't regenerate. Adult African clawed frogs, a common laboratory animal known in scientific circles Xenopus laevis, fit the bill. The amphibians are not normally regenerative but have some tissue renewal capacity, just like humans. "We were hoping to show that adult Xenopus frogs are capable of limb regeneration, and to find a trigger that allows it to happen," Levin said.

The trigger the team found is progesterone, the sex hormone involved in the female menstrual cycle, pregnancy and breastfeeding. The scientists applied the compound to frogs' amputated back legs with a wearable bioreactor device for 24 hours. Then they watched as the limb regenerated.

See also: These Flatworms Can Regrow A Body From A Fragment. How Do They Do It And Could We?

Brief Local Application of Progesterone via a Wearable Bioreactor Induces Long-Term Regenerative Response in Adult Xenopus Hindlimb (open, DOI: 10.1016/j.celrep.2018.10.010) (DX)


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  • (Score: 3, Funny) by purdy on Thursday November 08 2018, @11:37PM (1 child)

    by purdy (1863) on Thursday November 08 2018, @11:37PM (#759607)

    Now we'll never run out of frog legs!

    • (Score: 3, Insightful) by SpockLogic on Friday November 09 2018, @12:38AM

      by SpockLogic (2762) on Friday November 09 2018, @12:38AM (#759623)

      ... and the spectre of Lorena Bobbitt won't seem so scary.

      --
      Overreacting is one thing, sticking your head up your ass hoping the problem goes away is another - edIII
  • (Score: 1, Interesting) by Anonymous Coward on Thursday November 08 2018, @11:49PM (6 children)

    by Anonymous Coward on Thursday November 08 2018, @11:49PM (#759613)

    "There is no reason that human bodies can't regenerate," said Tufts University biologist Michael Levin, who led the new research.

    Really? I'd expect there is a very important reason this doesn't happen, or else it would already be going on. This is just common sense.

    Second, you can see the control frogs grow a "spike" after amputation while whatever they did leads to a "paddle" of about the same length:
    https://els-jbs-prod-cdn.literatumonline.com/cms/attachment/c9997e60-cc6b-4a21-839e-b12294b46e2f/gr3.jpg [literatumonline.com]

    So there is no regeneration of a leg, they just changed what the stump looks like.

    • (Score: 4, Interesting) by EventH0rizon on Thursday November 08 2018, @11:56PM (2 children)

      by EventH0rizon (936) on Thursday November 08 2018, @11:56PM (#759615) Journal

      Yes but they achieved this outcome (months later) with just an initial 24 hour long local application of progesterone. *They* are of the view that they might have found a master switch:

      It is likely that progress in regenerative medicine will be greatly augmented by identifying master regulators or triggers that, like our Prog device, can induce this complex set of downstream events without needing to micromanage each one.

      I think it's quite significant.

      • (Score: 0) by Anonymous Coward on Friday November 09 2018, @12:39AM (1 child)

        by Anonymous Coward on Friday November 09 2018, @12:39AM (#759624)

        All they did is mess up the healing process... if you get your leg cut off its better to have a fatty/muscular stump you can actually use for *some* support, not a useless flimsy flap of skin with a thin slab of bone inside that is going to break easily. I'm sure there are a million different ways to mess it up.

        • (Score: 2) by GreatAuntAnesthesia on Friday November 09 2018, @09:49AM

          by GreatAuntAnesthesia (3275) on Friday November 09 2018, @09:49AM (#759791) Journal

          Think you can do better? No? Well shut the fuck up then, you idiot luddite. What the hell are you doing on a tech / science website with such a stupid, backwards attitude?

          Regeneration is a massive, insanely complex area of research that has stumped (hur) scientists, doctors and researchers for decades, if not centuries. The biology they are dealing with is bogglingly complicated, unintuitive and hard to figure out, and you think you have the right to pour scorn on anyone who fails to produce fucking Wolverine on the first attempt? Here's a clue, dingbat: The real world doesn't work that way. Progress towards complex scientific goals comes mostly in small steps, incremental improvements like this one that quietly pile up until someone can finally collect all the pieces, put them together and shout "EUREKA!" (and grab all the fame and glory). That's pretty much the history of the last few centuries of science that underpin your entire modern existence.

          So show some respect, exhibit some patience and give these people some fucking credit. Maybe one day you'll need something regrown, and it will only be possible because of what you've read about here today.

    • (Score: 2) by exaeta on Friday November 09 2018, @02:26AM (1 child)

      by exaeta (6957) on Friday November 09 2018, @02:26AM (#759667) Homepage Journal

      The "good reason" has to do with what evolutionary setup is best for the species, not the individuals involved. A population that doesn't die isn't subject to natural selection, and so doesn't evolve quickly.

      Humans are past the point where we need to worry about evolving naturally.

      --
      The Government is a Bird
      • (Score: 0) by Anonymous Coward on Friday November 09 2018, @03:08AM

        by Anonymous Coward on Friday November 09 2018, @03:08AM (#759681)

        Humans are past the point where we need to worry about evolving naturally.

        This seems a bit hubristic.

    • (Score: 2) by Immerman on Friday November 09 2018, @03:44PM

      by Immerman (3985) on Friday November 09 2018, @03:44PM (#759898)

      Well, it does look like it regrew a great deal more bone, blood vessels and (presumably) muscle, and possibly even the beginnings of a knee and toes - in fact it very much resembles the middle stages of full-limb regeneration in species that can do that. In contrast the control "spike" appears to be almost completely soft tissue, and thus rather useless - probably wouldn't even work as a functional tentacle since the musculature is all designed to work against a skeletal system. Regrowing even a bony muscular stump could mean the difference between a prosthetic leg starting at the knee, or just at the ankle. Though that's probably primarily a psychological difference.

      If that's actually the beginnings of a joint though? That could mean the difference between a prosthetic elbow and a real one, and hints at the possibility of regrowing further joints as well, perhaps even the entire limb. If you had the choice between a prosthetic arm starting mid-bicep, or a full natural (if malformed) arm and hand, that could be very tempting. Especially since traditional plastic surgery could reconstruct much of the malformation. Heck, even if all you could regrow properly is a bunch of malformed muscle, bone, and nerve that could open the door to only needing a prosthetic skeleton rather than the full limb. Maybe not an end-goal, but a huge leap forward from where we are today.

      And even if all they they can get is mostly non-functional malformed growth that's a *huge* leap forward - essentially they've found a "gas pedal" for the regeneration process. A "steering wheel" is also important for getting where you want to go, but you need to start moving before you can begin experimenting to try to find that.

      Oh, and as for that important reason we don't regenerate, we've already found one big one - scarring. In general the more capable an animal is of regenerating, the less scar tissue it forms - and scar tissue appears to serve an important protective function in the immediate aftermath of a wound, especially on land where a fast, durable patch helps seal the wound against fluid loss and further damage. Unfortunately it also interferes severely with further regeneration, but if it keeps you alive long enough to bemoan your loss, then that's a huge win for evolution. Suppress the formation of scar tissue, and even mammals will regenerate a fair bit more than normal. Suppress it *and* stimulate regrowth? We shall see.

  • (Score: 3, Funny) by fustakrakich on Friday November 09 2018, @12:12AM (1 child)

    by fustakrakich (6150) on Friday November 09 2018, @12:12AM (#759619) Journal

    Otherwise we're going to end up with some 1000 pound frogs, and African Clawed frogs don't sound to friendly, if African bees are any indication

    --
    La politica e i criminali sono la stessa cosa..
    • (Score: 2) by Joe Desertrat on Friday November 09 2018, @11:32PM

      by Joe Desertrat (2454) on Friday November 09 2018, @11:32PM (#760136)

      Otherwise we're going to end up with some 1000 pound frogs, and African Clawed frogs don't sound too friendly, if African bees are any indication

      Many years ago I bought a couple of those little African frogs to add to a a fish tank community, just thinking they looked interesting and besides, they were really cheap. They turned out to be frighteningly gluttonous, essentially eating whatever and whenever food was in front of them. I don't believe they could see too well, but they would snap instantly at anything that passed close enough for them sense its presence. All the small fish in the tank disappeared within a week. When we fed the fish live brine shrimp, the frogs would sit at the bottom of the tank and use their front paws to shovel the shrimp continuously into their mouths. Fortunately they did not live all that long.
      If we somehow genetically engineered them into 1000 pound behemoths, about the size of really big alligators or crocodiles, we would have the makings of a horror movie worthy of the name. I can imagine one popping up at a swimming beach and gobbling people right and left, rather than just grabbing one and disappearing...

  • (Score: 3, Interesting) by opinionated_science on Friday November 09 2018, @06:27PM

    by opinionated_science (4031) on Friday November 09 2018, @06:27PM (#759979)

    A few years back, I visited a lab sequencing the Salamander Genome [nature.com], which has the trait that it is 10x the human genome.

    The motivation was/is of course, the limbs can be completely regrown so perhaps we can find out why?

    There is however some obvious logic that will dampen the spirits for those wishing to become Deadpool!!

    It takes a *phenomenal* amount of energy to grow a human limb - and perhaps 15 years!! Salamanders are really quite small, so a few days/weeks is probably not a stretch.

    A possible hypothesis (IMHO) is all the extra DNA allows some massively parallel processing of transcipts and ribosomes, to permit the huge amount of cellular regeneration that would be required.

    A human version, would probably require wearing a bioreactor in place to provide all the nutrients, and a few years!!

    I imagine that a 3D printing of the "skelatal" parts might suffice to jump start the process (this has been successful with hearts).

    On the bright side, if your liver could handle it , you'd convert a ton of fat....

  • (Score: 0) by Anonymous Coward on Friday November 09 2018, @08:21PM

    by Anonymous Coward on Friday November 09 2018, @08:21PM (#760063)

    Um, no. Dr Becker did this back in the 80s.

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