Thursday, 16 Sep 2021

A Promising New Way to Restore Hearing in People

We are able to hear the sound because of tiny hair cells that wiggle with sound waves in our surroundings. These hair cells actually have bristles in them that swing to and fro with the sound waves much like ocean waves. These wigglings are then transformed into electricity and transmitted by the nerves into our brain which we recognize as sound.

However, aging and other illnesses can destroy these tiny hair cells that result in hearing loss. But similar to brain cells, our hair cells are also limited and besides aging, damage caused by loud sounds such as high-volume MP3 players or jackhammers or very loud rock concerts is largely permanent. Hearing impairment and later hearing loss is therefore often inevitable for most of us.

But scientists have recently discovered that certain brain cells can be tricked into transforming themselves into these hair cells with sonus complete. Figuring out how to replace damaged hair cells has preoccupied researchers for decades and this time, they may have finally found the answer. They had tried other approaches such as using cochlear implants, stem cells and had even studied certain birds and fowls which are able to re-grow lost hair cells. The new research accidentally stumbled upon these potential hair-replacements in the lining of a compartment in the brains of mice and humans. These cells inside the compartments also contain hair-like extensions that resemble that of hair cells. Even more surprising is that both cells contain the same type of proteins.

One experiment they did was transplant these brain compartment cells into the tissue lining of the inner ear and the cells grew wonderfully as if natural hair cells. A later experiment was also done, this time putting the cells into a Petri dish with nerve cells that are known as spiral ganglion neurons. The nerve cells accepted the electrical signals sent out by the potential hair-replacement cells that came from brain compartments. It was such an unexpected event since neural transmissions are difficult to do in some cases.

In experiments with deaf mice whose hair cells were removed, the transplanted cells eventually learned to function similarly to the original hair cells. Scientists are even starting to call this procedure as a “biological implant” which is much superior to the cochlear implant mentioned earlier. They prefer this approach because cochlear implants tend to destroy all the remaining hair cells in the ear.

A biological implant using transplanted hair cells can be designed and refined only to portions of the ear which had lost its original hair cells. Surgeons have opined that removing and harvesting hair-cell replacements from deep inside the brain is no different than most brain surgeries and could become pretty much routine in about a decade.