Ears and regenerative medicine

Currently, when hearing loss and deafness occur we have no means to fully mimic our hearing. An artificial hearing aid is offered sometimes in the form of an implant for deaf patients. Through regenerative medicine we work towards models to better understand disease and to cure certain conditions in the future.

Current solutions: cochleair and auditory brain implant

When normal hearing aids show limited effect for patients with impaired hearing or deafness a cochlear implant can offer relief. This implant directly stimulates the auditory nerve in the inner ear, creating a ‘bionic’ ear. An alternate option is an auditory brain implant, where the signal is transferred directly to the auditory center in the brain. When impaired hearing is caused by a defect of the ossicles, artificial ossicles (some developed in Leiden) can replace the function. We are continuously improving the function of these bionic interactions through new computational models, imaging, electrophysiology, psychophysics and clinical trials.

Inner ear-on-a-chip and other regenerative future solutions

We are working on a so-called inner-ear on-a-chip. Using induced pluripotent stem cell (iPSC) culture techniques, we hope to create an in vitro model of the part of the inner ear that is responsible for the production of endolymph fluid. Dysfunction of this part is supposedly responsible for the symptoms of patients suffering from Ménière’s disease, such as vertigo, impaired hearing and ringing in the ears. Linking this ‘organoid’ to a ‘chip’ will give us the opportunity to measure the effects of relevant pharmacological products on the endolymph production, thereby creating a platform for drug testing. When grown from patients with genetic defects that are known to influence endolymph producing epithelium of the inner ear, the ‘organoid on-a-chip’ can even be used to study gene therapy. Furthermore, we have initiated research to use stem cells, specifically hair follicle bulge stem cells, as regenerative therapy for the auditory nerve and the vestibular organ.

Ear function and disease

To hear, sound vibrations in the air need to reach the eardrum. Via the ossicles vibrations travel to the cochlea, a fluid-filled snail-shell shaped structure. Countless cilia put the fluid in motion creating an electrical signal that is sent to the brain via the auditory nerve. When hearing is impaired and a normal hearing aid is not effective a cochlear implant can help. We execute about 80 cochlear implant operations per year. For patients suffering from neurofibromatosis type II or ossification of the cochlea (for example after encephalitis) an auditory brain implant can be of help.