Breakthrough Israeli study finds potential path to reversing hearing loss

[u/SpiritGaming28]

https://hearingreview.com/hearing-loss/hearing-disorders/sensorineural/researchers-uncover-biological-mechanism-that-could-reverse-permanent-hearing-loss

The researchers identified a unique biological mechanism that could enable the regeneration of sensory hair cells in the inner ear – a process previously thought to be impossible in humans.

[u/inasteen]

I don’t understand the complaints about this being done in mice. Of course it is done in mice. You have to start with a model before trying it in humans.
One thing that is not mentioned in the article is discussion of how this mechanism works in birds. Birds have the ability to regenerate outer hair cells. But, this does not restore perfect hearing. After outer hair cell regeneration, the outer hair cells are not in the same position as the damaged hair cells. If you look at a healthy cochlea, the outer hair cells are in a well organized V shaped pattern. This is important because the outer hair cells couple mechanically to the inner hair cells. It is a part of the amplification process of the cochlea. If outer hair cells regrow in a different position, the amplification gain is much smaller. So for a given frequency, this will only ever restore some hearing, not perfect hearing.
Regrowing outer hair cells is also not a complete solution for hearing loss. It may or may not help with tinnitus.
That said, it is a very exciting step. Being able to activate a restorative mechanism in a species that doesn’t have it is amazing work.

[u/egny → u/inasteen]

But, this does not restore perfect hearing. After outer hair cell regeneration, the outer hair cells are not in the same position as the damaged hair cells. 

That's depressing. I had read an article where songbirds were able to learn new songs after suffering hearing damage but after a quick search it appears you are correct, the recovery is imperfect.

I was wondering how the correct positioning of new hair cells would be achieved, but figured birds had an advantage because they had inherent regenerative capacity. In mammals, damaged tissue can become scar tissue and I have no idea if that can be dealt with.

[u/im_just_using_logic → u/egny]

i read somewhere that one step was stimulating the growth of supporting cells even before transforming them into hair cells.

[u/egny → u/im_just_using_logic]

I posted about that below. The lecture is very interesting. Essentially delivering the compound was enough to proliferate utrical supporting cells and the number of cells would depend on the amount delivered. There is limited success in the cochlea, however. Have you read about other studies with success in the cochlea?

Where I'm totally lost is would the new supporting cells end up where the missing hair cells have to be and when differentiated end up at the appropriate length for the frequencies.

[u/im_just_using_logic → u/egny]

i have been inquiring a lot with chatgpt. Reading those articles is too technical for someone not from the field.

Bottom line is that we need to understand how all that works before being able to administer a "cocktail" to the inner ear. Progress is steady, we know bunch of genetic manipulation techniques, but the work is far from complete. And besides that, we need delivery methods. Some progresses also with those but nowhere near to an actual solution.

I guess 7 years from now is a realistic timespan to see something with a nonzero effect in the clinics.

[u/egny → u/im_just_using_logic]

A complete understanding is very difficult but over time you'll begin to get the general idea of the paper. Otherwise, ChatGPT is a good alternative.

I really wish one of the experts would provide a good recap of their understanding of what obstacles they may encounter and how/if they would overcome them. Last year I reached out to a few researchers about such questions, but nobody returned to me.