Scientists have discovered a new method for restoration of hearing

Scientists have made an important step towards what may become a new approach to restore lost hearing. In a new study published in the European Journal of Neuroscience, scientists were able to restore the sensory hair cells located in the cochlea of the inner ear that converts sound vibrations into electrical signals, but may lose this ability due to age or noise.

Hearing loss has long been considered a reality of life of the elderly population – about 3 million Ukrainians suffer from some degree of hearing loss. However, scientists have noticed that other animals, namely birds, frogs and fish are able to regenerate lost sensory hair cells. Study co-author Jinyan Zhang, doctor of Sciences, representing the faculty of biology of the University of Rochester, decided to study this issue in more details:

It’s funny, but if we talk about the regeneration of cochlear tissues, mammals white crow among the other representatives of the animal world. Humans are the only vertebrates who are unable to do this.

Laboratory studies, conducted in 2012, identified a family of receptors called epidermal growth factor (EGF). This factor is responsible for activating the supporting cells in the auditory organs of birds. When activated, these cells proliferate and contribute to the generation of new sensory hair cells. The study’s author , Patricia white, research associate Professor at the Medical center of the University of Rochester, suggested that this signaling pathway could potentially be used to produce the same results in mammals.

In mice, snail activates the EGF receptor throughout life, but they, apparently, will never lead to regeneration of hair cells. Perhaps during the evolution of mammals, changes in the expression of intracellular regulators of signaling of the EGF receptor. These regulators could change the sound by blocking the regeneration. Our research is aimed at finding ways of switching the way, to start the regeneration of hair cells, and to improve their integration with the nervous cells, which is crucial for hearing.

In the new study, which was attended by experts from URMC and Massachusetts Ear and Eye Infirmary, the team tested the theory that signaling from the EGF family of receptors can play a role in the regeneration of cochlear function in mammals. The researchers focused on the expression of ERBB2 – specific receptor which is located in the cochlear supporting cells.

Scientists have studied a number of different methods to activate the EGF signaling pathway. The first part of the experiments included the use of a virus aimed at the receptor ERBB2. In the second part, experiments were carried out on genetically modified to sverkhekspressiya activated ERBB2 mice. The third part included the testing of two drugs, originally developed to stimulate the activity of stem cells in the eyes and pancreas, which are known to activate the ERBB2 signal.

The researchers found that the activation of the path ERBB2 caused a cascading series of cellular changes that the supporting cells of the cochlea of the ear begin to multiply, starting the process of activation of neighboring stem cells that become new touch voloskovye cells. In addition, it seems that this process can not only affect the regeneration of sensory hair cells, but also to support their integration with the nervous cells.

The process of restoration of hearing is quite complex and requires a series of cellular changes. First, you need to regenerate sensory hair cells, which then needs to function properly and to connect to necessary network of neurons. This study shows the signaling pathway that can be activated by various methods, and may represent a new approach to the regeneration of cochlear cells, which ultimately should lead to restoration of hearing.