Scientists regenerate hair cells that enable hearing
hms.harvard.edu
hms.harvard.edu
> Despite the progress in our approach to achieve HC regeneration in the adult cochlea in vitro and in vivo, major challenges remain before potential clinical applications. First, regenerated HCs need to be terminally differentiated and fully mature, and to be located in the sensory epithelial region such that their stereocilia contact the tectorial membrane to mediate the mechanoelectrical transduction, as well as be able to survive long term. The current regenerated HC-like cells are immature and the time frame we used is not ideal to determine their long-term survival. One potential reason for the lack of terminal differentiation is the continuous Atoh1 expression mediated by adenovirus, which is known to impact HC maturation and is detrimental to HC survival (9, 56). Future studies to express Atoh1 transiently in the reprogrammed SCs could address the issue. Second, the surgical procedure of “cochleostomy” in the adult cochlea severely damages the microenvironment of the cochlea including extensive OHC death around the injection site. Future studies using an alternative delivery vehicle with a minimally invasive surgical procedure such as an AAV with round window injection could significantly improve HC regeneration efficiency without causing trauma to the inner ear. Third, major efforts should be made to identify/create new AAVs or novel delivery vehicles such as nanoparticles capable of targeting adult cochlear SCs for reprogramming. Finally, the restoration of hearing in adult deaf animal models significantly and reliably by HC regeneration will elevate the field of HC regeneration to a clinically relevant stage.
It sounds like the authors have found a more effective way to trigger generation of immature Hair Cells than was already known, but they're several large steps away from "restoration of hearing in adult deaf animal models".
However, the submitted article (from hms.harvard.edu) summarizes the findings as:
> [Authors] reported creating a drug-like cocktail of different molecules that successfully regenerated hair cells in a mouse model by reprogramming a series of genetic pathways within the inner ear.
While it's not outright false, the "successfully regenerated" isn't the way I'd interpret the PNAS paper. Perhaps I misread the paper.
Anyway, great that another small but significant step is made in this terribly complicated problem :)
Hearing is complicated, this is a repost and it's believed many components need to be fixed in order to hear again. A drug (FX-322) was pulled recently after reaching stage 2 clinical trials and had good evidence of regenerating hair cells via progenitors in mice and cadaver.
Hair cells are not even considered the first thing to be damaged when one notices hearing loss. It's considered neurons connecting the audiotry nerve to and from the hair cell via the spiral ganglion cell are lost (both neuron and eventually the cell after a few months/years).
There is currently no way of reconnecting these or regenerating the SG cell.
I also think funding in this area is extremely low (looking at DoD and UK govs commitment's). Given the funding available I think researchers have done great but more money is needed.
The subreddit r/tinnitusresearch has good coverage of the scientific efforts. Which as you mentioned are not that many.
https://clinicaltrials.gov/ct2/show/NCT04677972
The trials have shown some degree of efficacy above controls. At this stage I only consider evidence from trials to get excited over, though it's important to be optimistic over lab results and research.
Hidden Hearing Loss: The Effects of Synaptopathy, Stanford.
I think there are different forms of hearing loss (hidden hearing loss, noice induced hearing loss, middle ear hearing loss, ...). I think noice induced hearing loss is most common nowadays and is caused by structural damage to hair cells. Regenerating hair cells might cure this particular form of hearing loss but not others. I think the one you mentioned has a different root cause for which new hair cells are only part of the puzzle.
> The new cells contained transduction channels that relay sound signals and the ability to form connections with auditory neurons — processes essential to hearing.
There's further questions on the models. Using Guinea pigs and mice yeild different outcomes. There's also questions on whether adult mice are better suited for hearing research.
Keep your cure for JS as far away from me as possible, thanks.
My family suffers from a mitochondrial disease in which effects these very hairs in our cochlea (which makes us great candidates for cochlear implants) but would this be "simple" for research such as regenerating hair cells?
One of the reasons we make such good cochlear implant candidates is we instantly hear. It's like the neurons/links were just waiting.
If this is of interest to you, or you could perhaps point me in the direction of someone in this space, you can find my via my profile :)
If I can get rid of the persistent high pitched whine in my left ear my QoL will go through the roof.
I guess I'm just lucky, or my hearing is just so sensitive that what I consider "loud" is actually fairly quiet. I know that I've had problems actually hearing sounds in band practice without using earplugs - I'd just hear a bunch of noise, and often lose the beat because of the inability to hear other musicians clearly.
It was called The Dead Room...
The first thing I noticed is that I had to speak a lot louder to be heard. But the most unnerving thing happened when we finally stood still in there.
I could hear my blood run through my own veins.......... So out of sheer panic I started moving and talking again lol.
This room was in the basement, and was secluded from all the other rooms in the building. The control room was even two stories up from the studio. They used it to record special samples that had to be completely "dead," as in no echo or reverberation on it outside the instrument itself. By they looks of it they also used it for Foley recordings, because there was some surfaces in there and some pans of powders and sand.
0. https://www.reddit.com/r/videos/comments/3oauru/if_you_have_...
YMMV.
For as long as I can remember I've had great difficulty hearing in noisy environments. In my younger years it didn't bother me too much as I was mostly at noisy events to enjoy the music anywhere, and if I wanted to talk we'd move somewhere quieter. If I make a concerted effort I can usually hear someone directly opposite me fine, though in an especially noisy venue like a concert I'm often filling in the blanks with lip reading or other visual cues. If I'm standing by something noisy in the house (range, operating vacuum cleaner, etc.) I can often tell someone is talking to me but usually have no idea what they are saying. All this has been on the "minor inconvenience" end of a personal impact spectrum. Recently I had a minor traffic accident (reversed into a car at very low speed, little damage and no injuries) and I realised that in that moment I had such little awareness of what was around me that it I was concerned. There was a lot of very loud conversation happening around me at the time. No screaming or anything, and I wasn't part of the conversation, but it was enough to completely destroy my focus at the time. I'd had a similar incident a couple of years prior. All this meant I decided I should book in to have my hearing checked.
Fast forward to the results: she said the tympanogram results show a highly compliant middle ear, but far more aggressively responsive than she'd seen before. Usually you'd see little or slow response if there was a problem but I'm the complete opposite of that. For the audiogram results I can hear into negative decibels but with a large enough delta in the results between left and right ear that I'll need to do some follow-up scans. She also ran two separate types of test to check for Auditory Processing Disorder.
Everything game back within range, or at least on the opposite side of what you'd call hearing "loss". Which prompted her to mention "but, at conferences lately they have been talking about a phenomenon that is presenting more frequently and being referred to as 'hidden hearing loss'...". So I've been down a rabbit hole of reading for the past week trying to filter out the things that a pure woo to the stuff that looks like it has some rigour to it. Seems like there's also been a trend for people to label some of these symptoms as "pub deaf".
I'm curious if any others on HN have had similar experiences and/or been down this research path before.
Now I also have some issue that eustachian tube gets a bit clogged up or something, because I react more than usual to small air particles. I can usually fix that by blowing while keeping my nose and mouth shut - but the issue above still remains in some form.
Might be the same thing depending on your full set of symptoms.
Whenever there is background noise, I cannot decipher what someone is saying. I’ve lost count of how many times I’ve been asked, “are you deaf?”
Could it be some form of ADHD?
This whole “hidden hearing loss” concept seems like such a broad term for a huge group of things. Some of them potentially related to dysfunction in the inner ear that we can’t test for but can be treated (in mice) with neurotrophin.
The specialist I saw said at the last conference she attended the researcher presenting on it said most patients presenting were in their 40s. I’ve not seen any papers that make such a claim though. I was only the second patient she’d personally encountered that had the symptoms, and we are both in our 40s.
I have both ADHD and "hidden hearing loss" and I chalk both up to my brain struggling to filter out noise/distractions.
If nothing else I’m finding the current journey interesting as I’m having to re-evaluate what is “normal” for both myself and others, for an experience that is obviously very personal and difficult to compare with others.
I got a job at a crowded and noisy casino. During some big events it was so crowded I had to walk sideways through crowds in the slot machine area. And very loud due to slot machines and people talking, yelling, screaming if they win.
Eventually I realized as I conversed with my co-workers we didn't need to yell and I could hear them 10 feet away. Note we did also use CB radios too but no mic just open speakers blasting which added to the noise.
I found out it is called the Cocktail Party Effect. It seems to be a learned skill that comes with time but it isn't something you naturally have. Ironically I probably now have hearing damage too working in that loud environment.
So there's a big demand for an effective way to restore damaged hearing.
I absolutely cannot do that anymore, given the damage it eventually did to my ears, but man, If I could heal my ears so I could go back and do that again...
Cases like this where it's caused by another issue are theoretically reversible though, right?
Depending on what you've lacked, for how long, your age—these are all variables. The younger you are, the lower the chances of reversing it as kids need a decent diet, period. How long you've been subsisting of off crap is the important one.
There was one highly publicized case about a kid who had gone deaf and blind from bad diet: https://edition.cnn.com/2019/09/03/health/poor-diet-blindnes...
With all the above said, one of my born-blind friends has started going deaf due to bad diet, and whilst changing his diet hasn't improved his hearing, it has massively improved his overall health and importantly halted the hearing loss at the rate it was going, so it's not been a pointless exercise to make a lifestyle change that'll benefit him in the years to come.
Wishing anyone reading this good health for them and theirs.
Oh wow. The Manga/Anime trope of male characters spontaneously bleeding from the nose when they get er... excited might actually have some real world examples.
Pretty sure "bleeding from the nose and ears" would kill the mood completely though. For most of the population anyway. ;)
If it wasn't dangerous, that could be useful in some situations.
ie. "I really don't feel like working hard today", so takes some Sudafed and gets on a Zoom/Teams call with work colleagues. ;D
Would probably only work once per employer though...
1.5 billion people (nearly 20% of the global population) live with hearing loss; 430 million of them have disabling hearing loss - https://www.who.int/news-room/fact-sheets/detail/deafness-an...
And the market for baldness cures has got to be at least as big as the market for hearing recovery, despite the gulf in fundamental importance.
They have:
https://www.thebrighterside.news/post/scientists-reverse-hai...
> The FX 322 gel contains drugs that early studies indicate helped to aid new hair cell formation. These are called progenitor cells, which are unable to evolve into any body tissue. Instead, they are usually more inclined to develop into cells near where they are found in the body. > This particular drug encourages them to grow into stereocilia, which are hair-like cells in your ears that detect sound. Hearing loss is when these hair cells are irreversibly damaged, as they cannot repair themselves.
[1] https://seekingalpha.com/news/3935169-frequency-crashes-75-o...
My friend mentioned he didnt meet the criteria for the study (I think age was the problem).
I'm happy to see developments on this area of research and I hope someone succeeds. Being deaf is very difficult for a specially social animal like us, humans
"Hair cells are the sensory receptors of both the auditory system and the vestibular system in the ears of all vertebrates, and in the lateral line organ of fishes. Through mechanotransduction, hair cells detect movement in their environment.[1]"
Wild guess: it is not actually what they managed to do.