Scientists in the second week of January 2013, at the Harvard Medical School, US developed a drug codenamed LY411575, which is claimed to be a cure of the permanent deafness. The drug works by exciting the inner ear. It actually triggers the restoration of sensory hair cells.
As of now, it was not possible to refurbish the cells which were lost because of various factors such as toxic drugs, infection and loud exposure of noise. This kind of deafness, which usually occurred to DJs and rock musicians, was assumed as irrevocable.
Scientists were successful in restoring the hearing in mice to some extent. These mice were deafened due to loud noise. The scientists believed that this research was helpful in creating effective treatments related to acute noise provoking deafness in the humans.
The sensory hairs which are very tiny are present in the cochlea and they are very crucial for hearing. Vibrations of the sound which are transferred from eardrum shake these hairs, leading to nerve messages transferred to the brain. In the absence of these hairs, the pathway to hearing remains blocked. As a result, the auditory centre of the brain does not receive any signals.
Fish as well as birds have the ability to regenerate the sound-sensing hair cells. Mammals lack this ability.
In the new approach, the scientists reprogrammed inner ear cells by reducing the protein known as Notch. In the early laboratory research, it was shown that the Notch signals enabled in preventing the stem cells in cochlea from transforming themselves to new sensory hair cells. Newly developed drug can curb Notch. In the study, mice suffering from noise-induced loss of hearing could generate functional sensory hair cells once the drug was injected in the damaged cochlea.
The study is significant because the hearing loss affects 250 million people in the world.