Hearing loss occurs when sound signals don’t reach the human brain. There are two main types of loss of hearing, depending on where the problem lies. Sensorineural hearing loss is one type of hearing loss that is caused by damage to the sensitive hair cells inside the inner ear or damage to the auditory nerve. This occurs as a result of injury or naturally with age. The other type is a conductive hearing loss that happens when sounds are unable to pass from your outer ear to your inner ear, often because of a blockage such as glue ear or earwax. Conductive hearing loss can be treated by proper cleaning of the blockage in the ear, but the sensorineural hearing loss did not have any treatment until now. A recent study suggests that doctors may now be able to regrow hair cells.
Scientists have discovered a combination of the drug that can regenerate hair cells in the human ear that detect sound waves and translate them into nerve signals enabling one to regain the sense of hearing. Every human being is born with about 15,000 hair cells in each ear. Hair cells damage is a leading cause of hearing loss. It is very critical as hair cells cannot be regenerated again.
The research concluded that the new combination of drugs can expand the population of progenitor cells known as supporting cells in the ear and induces them to become hair cells, offering a promising new way to treat hearing loss. “Hearing loss is a real problem as people get older. It’s very much of an unmet need, and this is an entirely new approach”, said Prof. Robert Langer, Massachusetts Institute if Technology. The researchers further added, the drugs can be injected into the middle ear, from which they would diffuse across a membrane into the inner ear.
For the research, the team exposed the cells from a mouse cochlea the spiral cavity of the inner ear containing the organ of Corti, that produces nerve impulses in return to sound vibrations grown in a lab dish, to molecules that stimulate the Wnt pathway, which makes the cells multiply rapidly. After a large pool of immature progenitor cells, the researchers added another set of molecules that aggravated the cells to distinguish between mature hair cells, which generated about 60 times more mature hair cells than the previously used technique. “We only need to advance the proliferation of these supporting cells, and then the natural signaling cascade that exists in the body will drive a portion of those cells to become hair cells”, said Associate professor Jeffrey Karp, Brigham and Women’s Hospital (BWH), Boston.