Spontaneous Hair Cell Regeneration in the Neonatal Mouse Cochlea in Vivo

Well ladies and gentlemen. I if I understand this correctly, then this isn't looking good.






Damage to cochlear hair cells results in permanent loss of hearing and effects 10% of the population. But, what if you could regrow these hair cells and restore lost hearing?

It has been established that hair cell regeneration in the auditory and vestibular systems does occur in chickens and other non-mammals, though not in humans. This spontaneous regeneration leads to restoration of hearing and balance, and may also prove to be essential in future cures for hearing loss in humans.

A new paper, published today in the journal Development, by Dr. Cheng, of the Stanford Initiative to Cure Hearing Loss, and Jian Zuo and colleagues from St. Jude Children’s Research Hospital, shows that spontaneous hair cell regeneration does in fact occur in the immature mammalian cochlea.

The findings in today’s paper are significant; as until now, though it has been possible to coax postnatal mammalian inner ear cells in culture to differentiate into hair cells, it was not believed that this process occurred spontaneously in vivo. Also, while prior research has shown the rare regeneration of hair cells in embryonic mice, until this point spontaneous regeneration had not been observed in the mammalian postnatal cochlea.

Hair cell regeneration occurs by two methods: direct transdifferentiation, where supporting cells directly become hair cells; and mitotic regeneration, in which supporting hair cells divide and one or both of the resulting cells develops into a hair cell. When hair cell loss was induced in mice at birth, the authors were able to observe spontaneous regeneration. They were further able to observe both methods of hair cell regeneration of hair cells and also the formation of hair cell bundles, necessary for the hearing process. Further, they were able to determine that spontaneous regeneration of hair cells did not occur after the first post natal week.

Many of the resulting hair cells did not survive, so the next step will be to further understand factors that can enhance hair cell survival, in addition to those that initiate this spontaneous regeneration. All of which are pieces in the puzzle of eventually restoring lost hearing in humans.

 

I dont think this changes anything - because it clearly states that there is no regeneration of hair cells after the first post natal week? This simply means that adults wont regenerate hair cells and isnt that what he knew before? However, a disvoery like this will make it a lot easier to approach humans!! I think this i a huge discovery and will help a lot on the way to treat hearing loss! Thank you for the article
Btw, are you participating in the injections of AM101? Id love to here how that goes, esp with your fear of needles and all.

 

I hope this is true. I think they were referring to the drug not working at post natal, but I really hope I'm wrong on this one. Does spontaneous regeneration mean without the drug? Let's say an adult chicken can't spontaneously re-grow the hair cells after a certain age, so the gene comes from a chicken that can't re-grow hair after a certain age, the drug would be the same for a human, since they took the gene to make the drug from a chicken. Also they say the hair cells didn't survive, so maybe that's what they mean, when they say that the next step is to further understand the survival of hair cells, and that cells can actually re grow post natal, but just need to find a way to keep them there.

 

I don`t believe they are making drugs out of chicken genes to recreate haircells ... they are investigating why chickens and birds alike can regrow them and discovering the obstacles in the human ear. These obstacles are outlined in various papers and also on the hearinghealthfoundation website ... So from that standpoint they are trying to overcome them and see the results. So the result is not working yet, but there is no drug made of chicken genes. They just blocked the notch signaling pathway which keeps the secondary cells underneath haircells as cells and not haircells. blocking this pathway made them grow into haircells but apparently the died of ... so next step is only understanding why this happend... they`ll figure it out.

having a second read makes it actually a really positive paper because it proves that there IS a spontaneous haircell regeneration process going on in mammals, just we need to discover to bring this process about in older mammals and also understand how to keep the cells alive. If this process wasn`t possible in mammals it would be a lot harder to try to bring haircells in the body from outside of the body grown in a culture-dish for example ...

 

I thought they blocked the notch signaling pathway using atoh1 in the rat model, which I thought was made from taking a gene from a chicken or something, but thank god.

 

I'm pretty sure that is how it works, but there's probably other factors that they dont know about yet that they have to figure out to get it to work well.

 

Ya I figured they were far past the stage of finding out why some mammals could regenerate these hair cells by now, since they've had to find some way of blocking the notch pathway in this mammal (mouse model) that could not restore hearing spontaneously after a certain age.

 

If so I was n`t aware it was produced like this. it is all to interesting what they are doing ... genes, molecules ... how can you even start imagining these things let along influence them.