Stem Cells and 'Regeneration' of the SGN's (Spiral Ganglion Neurons)

Seems like the research in the field of stem cells is making progress, this one is regarding the Spiral Ganglion Neurons. I have originally posted this as a reaction on another thread (regeneration of the inner ear), but I notice that some people are bothered by the concentration on 'hair cells'.

I, personally, have no noticeable damage on my audiograms (taken by different ENT's, in and out hospitals). A few weeks ago I read a research paper (I'll post it if I find it back) that this may be possible due to neural damage and that this damage can take several weeks/months to manifest (in contrast, hair cell damage seems to be more instant). Thus, I reckon that this research regarding the SGN regeneration might be interesting for some of us. I myself cope better with the whole ringing and sensitivity by keeping faith in the speed and progression of medical science and I believe that stem cell therapy (or derivatives) is one faithful way.

http://www.ncbi.nlm.nih.gov/pubmed/27021700
2016 May 15

"Spiral ganglion neurons (SGNs) are usually damaged in sensorineural hearing loss. SGN-derived neural stem cells (NSCs) have been identified and proposed to differentiate into neurons to replace damaged SGNs. However, it remains obscure whether SGN-NSC-derived neurons (ScNs) are electrophysiologically functional and possess the capability to form neural connections. Here, we found that SGN-derived cells demonstrated NSC characteristics and differentiated into SGN-like glutamatergic neurons. Neurotrophins significantly increased neuronal differentiation and neurite length of ScNs. Patch clamp recording revealed that ScNs possessed SGN-like NaV and HCN channels, suggesting electrophysiological function. FM1-43 staining and synaptic protein immunofluorescence showed ScNs possess the ability to form neural connections. Astrocyte-conditioned medium was able to stimulate ScNs to express synaptic proteins. These data suggested that neurotrophins are able to stimulate postnatal SGN-NSCs to differentiate into functional glutamatergic ScNs with the capability to form synaptic connections in vitro."

 

I really do not unserstand what scientific terms mean. So I want to ask a question because I also have quite perfect audiogram. No hearing loss. I got my T from glutamate storm from a benzo so this SPG neurons are still a thing with my kind of tinnitus? I know many people got their Ts from this shitty storm and also this is why they have no hearing loss.

 

Short answer is 'Yes'. I'm in my finals right now, so I'll answer in a better founded post later on!

 

There sometimes is a discussion hair cells versus connections to these hair cells.
If researchers are still exploring what actually is damaged after NIHL, ototoxic drugs, etc.., I am interested to read about this.
My audiogram for my right ear is far from perfect and I would be surprised if I have no hair cell loss and neural damage.
So, if in future stem cells initially only repair SGNs, I think this would benefit a lot of people. Also people with "dents" in their audiograms. Another step could be hair cell regeneration?

Yes, this makes sense when I think about my situation after acoustic trauma.
Right after this acoustic trauma my hearing was muffled. After the initial protection mechanism was back to normal (small muscles inside the middle ear) my hearing was still muffled. So I think that is hair cell damage/injury.
One month later the real problems slowly started. Hyperacusis, distorted hearing, tinnitus. That could be the SGN dying?
Especially with NIHL I think it is unlikely there is hair cell loss without SGN damage. So the SGN regeneration research will probably be beneficial for a larger group. I for one am enthusiastic about research into this SGN area!

 

Still waiting a more detailed answer from you

 

As of this day, I am officially finished haha. I'll sort my things out and will come back to you this evening or tomorrow!