The ability to regrow body parts is dormant in mammals, not lost

nnryoo about 3 hours ago 34 commentsRead Article on sciencedaily.com

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csr86•about 2 hours ago

Retina is a good example of this. Zebrafish can regrow damaged retina, but while mammals have the same stem cells (Muller glia), they dont repair the retina, but form scar tissue. There is a lot of research and I think they have managed to modify rat genome, so that their retina has showns some repair abilities. The problem is that it often causes tumors.

I have other retina permanently damaged, and suffer from double vision when looking small objects like text.

cortesoft•about 1 hour ago

Ah, I was wondering the evolutionary reason why those genes would have gone dormant.

Cancer is a sensible answer.

Sharlin•43 minutes ago

Yep, the unfortunate flipside of "let's use stem cells to rebuild stuff" is always "let's use stem cells to give us cancer". Technology might help alleviate the cancer part compared to blind evolution, hopefully.

api•5 minutes ago

Some aging mechanisms like telomeres are also mechanisms to prevent cancer by limiting cell division.

It looks like one of the optimization edges walked by evolution is a conflict between longevity and the ability to repair and regenerate versus not getting cancer.

It’s easy to make human cell lines immortal, but that will kill you.

stevenwoo•about 2 hours ago

I’m surprised this does not mention humans can grow back the tips of their fingers (past the white part of cuticle) https://www.npr.org/sections/health-shots/2013/06/10/1903854... Supposed to be only kids but I’ve chopped off a few mm by accident it came back as an adult or I can’t tell the difference.

roarcher•about 1 hour ago

Does your fingerprint look normal? When I was a kid I was goofing around with a pair of scissors and lopped off a good chunk of the pad of one finger. Thirty years later my fingerprint looks like a bunch of little dots at that location. The ridges never grew back properly.

VladVladikoff•about 1 hour ago

Same. Chopped off the tip of my thumb with an axe, it’s healed but very scarred and fingerprint is not normal.

adamors•about 1 hour ago

The exact same thing happened to me. I chopped off a good half a cm with an axe when splitting firewood about 5 years ago. After no less than 6 months there wasn’t any sign of the mutilation.

KellyCriterion•about 2 hours ago

2 years I ago I sliced maybe 1.5mm frommy thumb-tip; when taking off the bandage, I could clearly see the "straight cut" and that some material was missing.

Until today, it recovered completely

oniony•about 2 hours ago

What, last night?

delfinom•about 2 hours ago

Lol, I once sharpened my knives and went to cook. During the prep I said, "wow I wonder how sharp the knife is", next thing you know, i cut about 1/4" of my finger tip off, right through the finger nail with zero resistance.

Besides the blood getting everywhere and needing superglue to stop it, it grew back completely fine.

catlikesshrimp•about 1 hour ago

"During the prep I said, "wow I wonder how sharp the knife"" Is there something missing in the story? (drugs, coercion, self harm ideas, anything) I have had my fair share of avoidable cuts, but none of them included looking at the edge before happening.

stymaar•about 2 hours ago

Liver as well, but I have no idea if that's the same underlying phenomenon.

david-gpu•about 1 hour ago

Not a single mention of the work on limb regeneration by Professor Michael Levin's lab at Tufts?

https://as.tufts.edu/biology/tufts-center-regenerative-and-d...

joedevon•28 minutes ago

Was waiting for your comment.

anticensor•about 3 hours ago

The trick is to make regeneration fast enough to heal the wound without making fast enough to cause cancer. Maybe even supported by provisional fibrosis.

ck_one•about 1 hour ago

Does that mean zebra fish with their ability to regrow the retina get cancer at a higher rate?

NotGMan•about 1 hour ago

In a study they figured out that organs seem to have an electrical potential range as a signature/command for stem cells for which organ to build and where.

In a frog they were able to grow legit eyes in the gut just by artificialy inducing a certain voltage in that area. No need for any cell transplantations: the voltage really seems to be the only signal needed.

This might also be how it might be done in the future in humans: block scar tissue then induce voltage with the signature of the organ you wish to regrow.

https://pubmed.ncbi.nlm.nih.gov/22159581/

ranger_danger•about 2 hours ago

Wasn't this proven many years ago by a random guy who used a "extra-cellular matrix" of stem cells to regrow his severed finger, nail and all?

Found it: http://news.bbc.co.uk/2/hi/7354458.stm

lazyasciiart•about 2 hours ago

No, the end of your finger just can grow back. https://www.npr.org/sections/health-shots/2013/06/10/1903854...

Dude's brother had him throw his product on the finger as it did so, definitely an astute marketing trick. https://www.theguardian.com/science/2008/may/01/finger.claim

ranger_danger•about 1 hour ago

"I don't know how it works, so it must be fake news."

To be fair, the person being skeptical is just a surgeon, this is not a peer-reviewed study or anything actually scientific.

Your NPR link even shows that scientists realize there are still unknowns:

> "We think that nail stem cells may a have a special function to induce the whole regeneration process, including nerve attraction and growth of the bone," Ito say.

A cursory search seems to say that typical regrowth of a nail takes 4-6 months, but Spievak claimed his only took 4 weeks.

Can we say definitively that his "pixie dust" had nothing to do with it? I don't think so. Can we say it did have something to do with it? Also unknown... but the answer right now IMO certainly isn't a scientific "no."

buddhistdude•about 1 hour ago

Maybe that's what Jesus used on the people that he healed

cheema33•about 1 hour ago

> Maybe that's what Jesus used on the people that he healed

I think this is what all healers used. They were all way ahead of their time and clearly misunderstood.

petesergeant•40 minutes ago

In the whole Christian tradition, God/Jesus generally does not go for organ or limb regeneration. Two counter examples are a healed ear in Luke (but this may well have been resumption of hearing? details are a little light), and then a single Spanish example in the 1600s.

For His own mysterious reasons, He simply doesn’t go in for that stuff, however much intercessionary prayer ends up in His inbox.

krapp•about 1 hour ago

Jesus, if he existed, didn't actually heal anyone or perform any miracles. That's mythology, not reality.

buddhistdude•about 1 hour ago

How do you know?

kennyadam•about 1 hour ago

I think to claim that 2000 years ago there was one person who performed miracles and/or healed people that nobody else could, with no actual evidence it was done and nobody else has been able to do it since, you need a better response to someone questioning it than “oh were you there? prove it didn’t happen.”

krapp•about 1 hour ago

Because I'm a grownup who knows the difference between reality and make-believe.