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

64 pointsposted 2 hours ago

28 Comments

csr86

40 minutes 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

32 minutes ago

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

Cancer is a sensible answer.

stevenwoo

an hour 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

18 minutes 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

16 minutes ago

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

adamors

19 minutes 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

an hour 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

an hour ago

What, last night?

delfinom

an hour 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

32 minutes 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.

delfinom

8 minutes ago

I didn't look at the edge, I was just thinking of that idea while slicing some vegetables and coincidentally not paying attention at the same time.

rpastuszak

22 minutes ago

Irony deficiency

stymaar

an hour ago

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

anticensor

2 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

24 minutes ago

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

NotGMan

3 minutes 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/

david-gpu

30 minutes 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...

ranger_danger

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

an hour 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

30 minutes 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

32 minutes ago

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

cheema33

16 minutes 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.

krapp

13 minutes ago

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

buddhistdude

12 minutes ago

How do you know?

kennyadam

a minute 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.”