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Humans have salamander-like ability to regrow cartilage in joints
- catalogia 7y agoI've suspected that cartilage regenerates ever since I learned that long term knuckle cracking doesn't cause long term damage, despite the audible crack coming from cavitation (which can be very destructive to things like ship propellers, eroding the metal over time.) If it didn't, my hands would probably be crippled by now.
- hanniabu 7y agoI thought it was known that cartilage can regrow but it's just at such an incredibly slow pace due to lack of circulation that you can effectively say it doesn't grow? Edit: after some googling I found this result > age 15 or 16 would be about the average age for bones to stop growing, so from that point on, there is no collagen regeneration in the cartilage. Your body, on its own, cannot regenerate the cartilage it loses in its adult years. https://regenexx.com/blog/does-cartilage-heal-on-its-own/ https://regenexx.com/blog/does-cartilage-heal-on-its-own/
- thatcat 7y agoThat source is over simplifying; some bones and cartlidge are known to continue growing in adults - the jaw and ear lobes for example.
- convery 7y agoThat does sound weird considering how many athletes develop issues later in life due to build up of cartilage. My friend, 66, for example did boxing in his late 20's and started getting issues in his 50's due to nasal-blockages, to the point where he now needs to drill away some of the cartilage to get rid of migraines and such..
- rjsw 7y agoCauliflower ears in rugby players would be another example.
- targonca 7y agoCauliflower ears are caused by the ear cartilage dying off and being replaced by fibrous scar tissue. That's definitely not cartilage overgrowth.
- joncrane 7y agoTrue hyaline cartilage cannot "build up." The good stuff (intra articular) is a precious resource that you can only lose, not gain. The cartilage in your nose and ear are different, and besides, the stuff that's blocking your boxer friend's nose, and causing cauliflower ear is not really cartilage. It's fibrous growth which has a blood supply. It's your body trying to replace real cartilage with a poor substitute.
- ChrisBland 7y agoExactly, not all cartilage is the same. The good stuff doesn't come back unfortunately.
- kevin_thibedeau 7y agoThey're selling a product that depends on you not knowing the truth. Medical hucksters routinely lie with facts.
- MisterOctober 7y agoI learned a little about this topic recently after a bad knee injury from running [torn meniscus] -- Blood supply does have a lot to do with healing-or-not -- taking the meniscus as an example, about 30% of the meniscus has a blood supply, the rest does not, so that if the injured part is of that 30%, it can actually heal, whereas if not, they can only clean it up and stitch it together like a rag doll --- [for the curious : I got lucky and my injury healed tolerably well on its own sans surgery]
- sachdevap 7y agoDoes knuckle cracking have anything to do with cartilage? I suspect it is not a related process. https://www.medicalnewstoday.com/articles/259603.php https://www.medicalnewstoday.com/articles/259603.php
- throwaway_law 7y agoI believe the prevailing thought on the audible cracking is that it is the bubbles in the fluid between cartilage and nothing to do with the cartilage itself.
- catalogia 7y agoThat's my understanding. But the collapsing bubbles are next to the cartilage I believe, and it seems to me should therefore be causing cavitation erosion. When cavitation erodes a boat's propeller, the cavitation is occurring in the water next to the propeller, not in the propeller itself. https://en.wikipedia.org/wiki/Cavitation#Cavitation_damage https://en.wikipedia.org/wiki/Cavitation#Cavitation_damage
- mikelyons 7y agoHere's a video of it happening on live x-ray: https://www.youtube.com/watch?v=ZyUjH2FmRLE https://www.youtube.com/watch?v=ZyUjH2FmRLE Quite creepy
- s_y_n_t_a_x 7y agoThe cracking sound is caused by nitrogen bubbles, not by cartilage breaking. Cracking your knuckles is safe as far as we know, if anything it probably helps because you're stretching your ligaments.
- mikelyons 7y agoDoc told me your tendons can end up taking up the slack, which can cause other issues
- rpmisms 7y agoSo, this would seem to open up possibilities for transplants and/or gene therapy?
- djohnston 7y agoi hope so. my spine is 30 going on 95 :(
- pfrench42 7y agoYou should consider looking into Prolotherapy. I had increasing levels of lower back pain since I was twelve. It had gotten so bad I couldn't roll over in bed without sharp pain. My neighbor was a naturopath, I helped him photograph some before/after xrays of a 70 year old woman's knee (before was bone on bone; she regrew her meniscus and bone spurs disappeared) I did three prolotherapy sessions (they're painful) with him over a few months and I have been pain free for over fifteen years now. I actually started playing rugby after my first session.
- dajohnson89 7y agothis is fascinating. who could i talk to, with more questionS?
- pfrench42 7y agoThis is his website. Be warned, naturopaths are a little odd and opinionated. :) http://www.arizonaprolotherapy.com/ http://www.arizonaprolotherapy.com/
- phkahler 7y agoThere is nothing proven in this article. They seem to have some new insights into the process, but they have not demonstrated any capability yet. We all have the ability to generate cartilage and limbs, that's how we got those things. The open question remains as to why some animals can do so again and humans dont.
- ignoramous 7y ago> The open question remains as to why some animals can do so again and humans dont. One of those talks that blew me away: https://www.youtube-nocookie.com/embed/RjD1aLm4Thg https://www.youtube-nocookie.com/embed/RjD1aLm4Thg Professor Michael Levin talks abt how certain animals regrow their body parts and how this process can be transmuted to other species. A very nascent but civilization altering research. Edit: HN discussions: https://news.ycombinator.com/item?id=18742131 https://news.ycombinator.com/item?id=18742131 https://news.ycombinator.com/item?id=18736698 https://news.ycombinator.com/item?id=18736698 (thx u/carapace)
- carapace 7y agoYou beat me to it. (I linked to the same talk in a sib comment.) This is probably one of the most important lines of research today. One thing I'd like to point out: He keeps saying "it would be cool to have technology like this", I think it's really important to remember that we are "technology like this". For example, rather than grow organs in labs and transplant them, maybe we can learn to (re)grow our own organs in situ.
- dajohnson89 7y agoOn a somewhat-related note: would glucosamine chondroiton pill speed this process? There's a lot of debate whether they do anything at all.
- loeg 7y agoThis specific process? Who knows. Evidence for efficacy of glucosamine in general? Summary by random website[1] says strong evidence of weak effects, no evidence of strong effects. [1]: https://examine.com/supplements/glucosamine/#effect-matrix https://examine.com/supplements/glucosamine/#effect-matrix
- clairity 7y agono, those get broken down by the digestive system, and as other commenters have noted (despite the article title), there is no way for the body to use it anyway.
- ineedasername 7y agoI had to have surgery for a minor tear in my wrist a few years ago. They didn't know going in precisely what they'd find, but knew that if it was a portion that had blood flow, they could repair and thing would grow back. If there was no blood flow, they most they could do was clean the tear area, stitch things back a bit, but they'd always be a little weak and I'd always have to be careful not to reinjure.
- npongratz 7y agoDon't keep us in suspense :) What did they find in your case?
- ineedasername 7y agoHah, sure: They found there was still some minimal blood flow, so it was kind of an in-between case. It means that with physical therapy, I mostly recovered, and if I strain it a bit I don't have to worry too much about tearing it again, I just end up in a bit of pain, wearing a brace for a few days. Of course I'm still overly careful, so that helps too.
- mrexroad 7y agoI had similar, but they knew what they’d find. So they just cleaned up the shredded flaps of my TFCC and shortened the ulna ~3mm (it was abnormally long).
- Nuzzerino 7y agoLink to the actual paper: https://advances.sciencemag.org/content/5/10/eaax3203 https://advances.sciencemag.org/content/5/10/eaax3203
- ChrisBland 7y agoI wish this was true. I've had cartilage damage in my elbow from sports and have gone through major surgery over it. This technology has always been '10 years away'; from mesh or paste with stem cells, to other 'new' technology to regrow it. It simply is not there yet. I check every year, I reach out to any doctor starting a clinical trial. Hyaline cartilage does not regenerate naturally. The best they can do is get the body to reproduce Fibro cartilage which is essentially scar tissue. For those wondering about what treatments are available, check out Microfracture (breaks bone to release bone marrow cells to generate Fibro), OATs (osteochondral autograft transfer system) which pulls cartilage out of other areas and then places them in the damaged area. If this were to ever be true, it would be the biggest breakthrough in quality of life improvements for seniors as they are the most likely to experience breakdown in cartilage in joints. It severely limits their mobility.
- hangonhn 7y agoI think we are in the same boat. Mine's in the knee and I have microfracture to "fix" it but I think if the paper is correct then it does mean hyaline naturally regrows because there is no fibrous cartilage in those joints so this result should only apply to hyaline, no?
- Xcelerate 7y agoI have an internal debate with myself over which will come first: nuclear fusion as society’s primary energy source, solving P vs NP, or repairing damaged cartilage. My bets are on the former two. (Also, I had the OATS procedure 9 years ago; it didn’t really fix anything unfortunately.)
- thfuran 7y agoI'd guess they'll occur in reverse order. Or at least fusion last. There are some serious engineering concerns to work out. And even if it were to become economical and reliable overnight, there'd still probably be a few decades before it replaced enough existing infrastructure to be the primary energy source.
- 7y ago
- carapace 7y agoChildren under the age of seven or so can regrow the severed tip of a finger. See https://en.wikipedia.org/wiki/The_Body_Electric_(book) https://en.wikipedia.org/wiki/The_Body_Electric_(book) and "What Bodies Think About: Bioelectric Computation Outside the Nervous System (youtube.com)" https://news.ycombinator.com/item?id=18736698 https://news.ycombinator.com/item?id=18736698
- myth_drannon 7y agoOne of the best talks I saw in recent years. The topic is so different from the usual stuff I see HN.
- sfink 7y agoI read that book long ago. He found regeneration happens a lot more than in just kids' fingers. Given nerves in the right places, it sounded like the biggest obstacles were scar tissue and infection. (The latter is most likely why we evolved to prefer the former over regeneration. A permanently scarred animal survives much longer than a gangrenous one.)
- tjpaudio 7y agoThis is something I have long suspected. I have definitely heard of instances where friends subsequent MRIs have shown regrown cartilage in the knee, but years later. And it doesn't happen for everyone. The friends that regrew, they were runners, they took their injury seriously, they kept moving but were very serious about maintaining flexibility, diet, hydration, etc. I think if you wear down your cartilage, but do nothing to address the tightness that caused the wear in the first place, then you will not see regrowth. The fact that this is an interesting research finding is reflective of somewhat a sad fact in my eyes: people generally do not take care of themselves, instead hoping for surgery or a pill or procedure. Few will add an hour of rehabilitative work to their daily routine and instead just live with the issue forever and complain. I have herniated discs, torn bicep tendons, had tendonitis nearly everywhere at one point or another, sublexed my knees, but nearing 40 I still am active as ever with no daily pain. Some of these injuries took me years to recover from, but recover I did.
- lallysingh 7y agoWill I think part of that is that a surgeon or pill tell you simple instructions and you have a good idea on what to get back. Exercise is way better but you get no guidance on whether you're doing it right or if it's working.
- omegaworks 7y agoThing is daily pills and even surgery are far more scalable than finding competent rehab facilities that can take patients regularly. This is an incredible problem that I think technology is nearly on the cusp of changing. Gamification[1] of the process, externalizing the internal motivations that drove you to continue those good habits will be critical. 1. https://youtu.be/AdoVBbZ0Z9o https://youtu.be/AdoVBbZ0Z9o
- whoiskevin 7y agoBull. I've had cartilage worn out in my knee for years. I remain active and take it very seriously. You don't get "regrowth" and recover. And frankly I don't believe MRIs have shown regrowth...this is a constant rumor I hear all the time and yet no one shows any consistent formula for this regrowth which means it is either false or just rare and not reproducible.
- DanTien 7y agoHas anyone any experience with stem cells? I believe the efficacy of PRP pales by comparison although I'm pleased to hear others success with it.
- padpnut 7y agoI’ve had multiple PRP injections on my ankle and it helped dramatically. I had chronic ankle pain and found it painful just walking. After 2-3 PRP injections it helped reduce the pain by 80%.
- Xcelerate 7y agoAs someone in my late 20s with cartilage damage in both my knees and back due to sports, this progress can’t come soon enough. I miss running a lot (and miss not having constant back pain), and it’s confounding to me why something that appears so simple, cartilage repair, has made almost no real progress over decades (I know it’s not simple). I keep following the research and hoping new discoveries will eventually lead to something tangible.
- 40four 7y agoRight there with you... can we please find a way to trigger this regrowth in my knee that I had a meniscectomy on! :) It is next to impossible to do any jogging any more without having a multi day recovery period from the inflammation. Doesn't seem to be any tangible methods in this article, but I've heard some promising stories of successful stem cell treatments.
- JoeAltmaier 7y agoMy son lost a chunk of his thumb joint to a router accident. The doctor saw the mess, and bandaged it up for 6 days to let the bleeding/soft tissue damage resolve some. When unbandaged 6 days later, the thumb cartilage in that joint was back, and the thumb worked fine. No surgery; no more attention needed. Still working 10 years later!
- mikelyons 7y agoDid he just rub some dirt on it? How do you explain this?
- JoeAltmaier 7y agoRelated to Wolverine I guess.
- eledumb 7y agoI had a pretty horrific left knee injury wrestling. I was carted off to the hospital, when the accident was described to the Orthopedic surgeon he actually recoiled and was concerned I may have totally destroyed my and that it might not be repairable, it was 1979. From the time of the accident until I was in surgery it was less than 3 hours. Somehow I managed to only stretch all my knee ligaments, ACL PCL,MCL,LCL, a few small inline tears, but nothing severed, but he said they were like overused rubber bands all stretched out. I did however shred all the cartilage. The cartilage was a mess, so much so that when they surgically removed all the cartilage from my knee. I have the video of the surgery, all my knee cartilage was removed, they scraped the bones in order to give me the smoothest ride possible, but it doesn't do much. When you don't have cartilage in your knee it's pretty obvious. Fast forward 22 years to mid 2001 when I start following the teachings of Linus Pauling regarding L-Ascorbic Acid and L-Lysine for heart disease prevention. I started taking high levels of both in divided doses during the day. My stress levels plummeted, and my overall health significantly improved, but after about 6 months I started to notice my knee was changing, a lot. My pain was going away and I didn't notice the bone on bone activity, after about 9 months my knee stopped hurting completely. In fact it felt so good that I started walking for exercise, normally after 5 minutes of walking I felt like I was gun shot in the knee, but nope I was able to walk fine for as long as I wanted. I then started jogging and then running, no pain, no pain at all. I've seen my orthopedist and while he's not willing to just give me and MRI, based on all of his examination he said my left knee is no different then my right knee and he didn't believe me that I had all my cartridge surgically removed 20 years before. I took the video, just in case, and I played the video. My knee has a unique scar from when I was a child and fell on a bottle, I had the scar when they performed the surgery and shot the video and I still have the scar, so there is no doubt that all my cartridge in my knee was surgically removed in 1979. L-ascorbic acid and L-Lysine are basic building blocks for cartilage. I'm just a sample size of one, but I know my cartilage is back, maybe not all the way back, but more than enough back that my knee rock solid stable, it's smooth as silk, I have no pain and my orthopedist can't find a difference in my knees. For what it's worth.
- majjam 7y agoWould you mind sharing how much you take or would it be clear if I research Linus?
- jdmcnugent 7y agoOrthopedic surgeon here. Articular cartilage regeneration is definitely the holy grail of my field, but for all of the promises of biologics (growth factors, stem cells, collagen matrices) it always seems to be “another five years away”. The part of this article that I find most interesting was identifying a marker that can differentiate ankle cartilage vs the hip. This is certainly a phenomenon that we all observe clinically, hip and knee arthritis is vastly more common than ankle arthritis despite the weight bearing surface of the ankle being significantly smaller (meaning more force per square area). When we do encounter ankle arthritis, it is almost always the result of prior intra-articular fractures or instability from chronic ligamenous injuries, not the normal osteoarthritic age related degeneration we see in hips and knees. Let’s find out what makes ankle articular cartilage so special and sprinkle it in our hips and knees.
- BurningFrog 7y ago> it always seems to be “another five years away”. I'm old enough that maybe I can supply some hope. For about 15-20 years, the same thing was said about flat screen monitors. They were "always 5 years away". And then, quite suddenly as I remember it, they were everywhere!
- drak0n1c 7y agoGood point about ankle cartilage, here is a detailed study about how ankle cartilage is different: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5154419/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5154419/
- warent 7y agoThe way you wrote this was really fascinating an informative. Was disappointed not to see a link to a personal blog or anything on your profile. I could read a lot more of your stuff.
- jdmcnugent 7y agoThanks for the compliment, I just lurk here on HN and I finally came across something in my wheelhouse. Happy to contribute. With private practice and a house full of kids I imagine my blog should be ready by 2029.
- ajcarpy2005 7y agoI recently read _The Body Electric_ and it gives insights into the body regenerating limbs.
- mrwebmaster 7y agoI have broken my both knee cartilages. First time when I was 23 and recently when I was 35. Fist knee recovered successfully after some years (I'd say about 5 years). The second injury was 2 years ago and the knee is almost 100% recovered, I feel some little pain only after running 10K and also after playing soccer. Both injuries were in the outer meniscus. There is a difference in the inner and the outer meniscus (perhaps the inner cannot recover because of less blood flow?). I didn't go to surgery. Things I can do without any pain whatsoever: running 5K at a fast pace, karate, barbell squat.
- throwaway123x2 7y agoI have stage 3 chondromalacia + flat feet + loose joint, an incredibly unholy trinity. Nothing amount of PT seems to work and the arthsocopy didn't help much either. If anyone's got any tips, I'd love to hear them.
- elcritch 7y agoOne interesting tidbit that this article doesn’t mention is that fiber orientation of cartilage is fundamental to the functionality of different cartilaginous tissues. It’s similar to how fiber orientation in carbon fiber parts will be adjusted to provide strength and durability in specific directions. Articular cartilages likely is somewhat more evenly oriented, but tendons are highly aligned to length and meniscus aligned in a hoop like direction. New or repaired cartilage in different tissues need exercise and other forms of mechanical agitation to align properly. Even if we could repair all cartilage readily we’d still need lots of physical therapy and to regrow damaged tissue at a slow pace. So no miracle sir on the couch cures even if this works. On another the meniscus (and vertebrae discs?) loose blood flow after mid-30 or thereabouts and might make effective delivery or healing more difficult. It’ll be interesting to see what happens in the next decade or two!