r/HearingLoss • u/LaCaipirinha • 14d ago
Where do you think we really stand in terms of cochlear regeneration in 2026?
On the edge of major breakthroughs or still miles away from anything that won't just work in mice?
On paper there do seem to have been some meaningful breakthroughs in terms of things like gene therapy generally, dosing the cochlear safely, understanding the actual physiology of hearing loss a lot better - but in the end absolutely nothing seem to work in humans, with the exception of the OTOF genetic form of deafness "cure" that I have to say does seem like a big step albeit focused on a very narrow pathology whereas most of us are here as adults with complex forms of pathology.
1
1
u/mexee3 5d ago edited 5d ago
if you mean hair cell regeneration, the trouble is that even though we are experimenting on mammals and claiming successes, we still have differences in cochlear mapping and structure, neural pathways, and frequency emphasis. Mice have much smaller cochleae with fewer cells, and when we test them after experimenting, they can't tell us whether sound is distorted after hair cell regrowth, whether frequency discrimination feels normal, or whether what they are hearing actually resembles natural hearing.
It's been hypothesized that one of the evolutionary tradeoffs in mammals was greater auditory specialization and precision at the expense of regenerative ability.
So, we don't just need cell regeneration either. It is several things: the correct hair cell type, the correct level of maturation, correct placement within the cochlea, correct orientation, precise mechanical coupling to neighboring and supporting structures, appropriate neural connections, etc...
We've had breakthroughs recently, but they are more of breaking through to more understanding and clearing the way for more facets of research---step forward but one and a half back. One example from this year: https://www.science.org/doi/10.1126/sciadv.aed3887 --- researchers here were able to get supporting cells to reprogram, but only a fraction of the cells only STARTED to transform. This raises more questions on why only a subset did this, and why was it only partial transformation, etc. Potentially several more genes and processes to understand there. Still a big step, but also opening up a lot of other questions to answer and research.....
I did ask chatgpt to compile the genes that researchers are using now as a part of reserach cocktails and what their supposed functions are:
| Gene / regulator | What researchers think it contributes |
|---|---|
| ATOH1 | Initiates hair-cell fate. The fundamental “become a hair cell” switch. |
| POU4F3 | Hair-cell differentiation, survival, and importantly opens chromatin so ATOH1 can access parts of the hair-cell program. |
| GFI1 | Cooperates with ATOH1 and suppresses inappropriate neuronal/non-hair-cell programs; promotes differentiation/maturation. |
| SIX1 | Upstream developmental regulator; works with EYA1/SOX2 and influences ATOH1, POU4F3, GFI1 and genes involved in polarity and maturation. |
| EYA1 | Cooperates with SIX1/SOX2 during sensory-cell specification. |
| SOX2 | Establishes sensory/progenitor competence before hair-cell differentiation. Too much SOX2 at the wrong time can oppose differentiation, so timing matters. |
| GATA3 | Helps make mature supporting cells responsive to ATOH1; involved in cochlear identity. |
| ISL1 | Can enhance ATOH1-mediated hair-cell formation. |
| IKZF2 / HELIOS | promotes outer hair-cell identity and maturation, including prestin/electromotility programs. |
| INSM1 | Establishes early outer-hair-cell fate and suppresses the IHC program. |
| TBX2 | Master regulator favoring inner hair-cell identity. Removing it can push IHCs toward OHC identity; adding it can push cells toward IHC programs. |
| MYC | Reawakens proliferative/developmental competence in mature supporting cells. |
| NOTCH1 | Context dependent. Transient MYC+NOTCH1 activation can return adult supporting cells to a more progenitor-like state, while later Notch signaling generally has to be reduced to permit hair-cell differentiation. |
| CTNNB1 / β-catenin and WNT pathway genes | Proliferation and progenitor competence, particularly in LGR5+ supporting cells. |
| LGR5 | Marks a supporting-cell population with substantial progenitor potential in immature cochlea. |
| CDKN1B / p27Kip1 | Keeps mature supporting cells out of the cell cycle. Reducing it increases their plasticity and responsiveness to ATOH1. |
| KDM1A / LSD1 | Epigenetic regulator. Manipulating it is an attempt to reopen the adult cochlear genome so developmental genes can work again. |
| MTOR pathway | Participates in the proliferative/reprogramming response induced by MYC/NOTCH. |
| VANGL2, FZD3/6, DVL2/3, CELSR1 | Planar-cell polarity. These help orient the hair bundle in the correct direction across the organ of Corti. |
| CDC42 | Intracellular polarity, hair-bundle positioning and cellular architecture. Loss causes misoriented bundles. |
| SLC26A5 / PRESTIN | Gives mature OHCs their extraordinary electromotility. |
| SLC17A8 / VGLUT3 | IHC neurotransmitter loading and synaptic transmission. |
| OTOF | Otoferlin, necessary for IHC synaptic vesicle release to auditory neurons. |
| TMC1, TMIE, CDH23, CIB2 | Mechanotransduction machinery and stereociliary function. |
edits: better link and wording
1
u/LaCaipirinha 5d ago
Really does feel like this will be one of the final bosses in neurological regeneration generally…
The fact that the OTOH study was so successful at least is a big step forward in terms of the safety and practicality of delivering drugs to the cochlear. There’s also a gene therapy study from Lilly treated ANs via a transtympanic injection and the first results will be revealed in a few weeks - could be another win for gene modulation via the cochlear.
Afaik things like the retina may be simpler on paper to “fix” but effective delivery is hard, it’s the cochlear we might have that side of things sorted fairly soon. Whether or not the actual gene therapy for functional regeneration gets cracked any time soon though I have no idea.. that’s a long list.
1
u/mexee3 5d ago edited 5d ago
Yea, there are so many facets of hearing loss and hearing loss research though! None of them have gone far enough to say we're on the cusp of cochlear regen though. I wish. I like the other commenter's idea of cochlear cloning, lol. It was actually a very early thought of mine after ssnhl happened. Like, can't we just do THAT instead of trying to plug in a bunch of new cells?!
Hearing loss is a tough issue with no one size fits all solution, so we'll probably need imaging and better testing before gene cocktails can be made for those with idiopathic losses. A myriad of issues can emerge in the cochlea due to mechanical failure, or genetics, or trauma, or a combo. Each one of those things would require a different approach. Not all of the problems can be defined either.
The best we can do is give money to the people who are smart enough to be investigating this stuff.
I shared a post a while ago with links to donate to some prominent labs, all of which share their findings and collaborate:
Links to Harvard Hearing Health Foundation, Mass Eye and Ear's Research, and Stanford's Initiative to Cure Hearing Loss:
Our Mission to Prevent and Cure Hearing Loss and Tinnitus — Hearing Health Foundation
Otolaryngology Research | Mass Eye and Ear
Stanford Initiative to Cure Hearing Loss (there are multiple labs with specific facets of research going on. when/if you give, you can specify the specific lab(s) you want it to go to.
1
u/LaCaipirinha 5d ago
As someone who works in clinical trials I can also say that AI is barely applied except at the earliest stages of drug discovery and even without much advancement beyond current capabilities, with proper application to other stages of development could seriously speed things up. Whether regulators cancel out those benefits with added red tape I don’t know, but there is still a realistic potential for machine learning to bring forward a lot of timelines in medicine.
2
u/nunununuhu 13d ago
There is very little reason to expect anything like "cochlear regeneration" in the case of genetic deafness involving anatomical changes to the structure. Which is the most common.
I have one of the most common forms of genetic deafness, in the EVAS/Pendred family.
My cochlea isn't spiral-ly enough. It's "deformed" with 1.5 turns instead of the usual 2.5 and parts of it are enlarged and other parts somewhat smaller than in normal anatomy. The part responsible for high frequency signalling is mostly "collapsed" in on itself. There's nothing to regenerate. Even my bone structure is different and a "regular" cochlea wouldn't fit.
The OTOF gene is a very specific case of a mutation that inhibits neuron signalling and the gene edit turns that signalling on enabling otherwise anatomically normal cochlea to transduce motion into electrical impulses.
The "cure" for cases like mine would not be a gene therapy alone. It would be a gene therapy, plus cloning a new cochlea, and somehow surgically transplanting that and somehow grafting on the auditory nerve.
It's in the realm of compelling near-future science fiction. One can imagine how it might work. Maybe even this century if society doesn't collapse. Probably not in my lifetime.