By John Galvin, Research Scientist, and Sean Lang, Clinical Research Coordinator
Corticosteroids, commonly referred to as steroids, are a type of anti-inflammatory drug. They are a front-line treatment for Ménière’s
disease and sudden sensorineural hearing loss. Steroids are typically administered via trans- tympanic injection, where a syringe needle is used to puncture the tympanic membrane (also known as the eardrum) and deliver the steroids to the middle ear. One drawback to this approach is that the concentration of steroids that successfully diffuse from the middle ear to the inner ear may vary from treatment to treatment.
A novel approach toward delivering therapeutics to the inner ear is “sonoporation,” where microbubbles containing the medication are pooled in the ear cavity and then delivered to the inner ear via ultrasound. The ultrasound excites the targeted tissues and makes them permeable. It allows the microbubbles to pass through the tissue into the inner ear, where they are picked up by the perilymph and delivered throughout the cochlea.
While sonoporation may be a less invasive and more effective approach to delivering therapeutics to the inner ear, it is not yet approved for use in humans. Thanks to a Development Grant from the House Institute Foundation, David Bakhos, MD, PhD, a House Institute adjunct faculty member in Tours, France, has begun testing the safety and efficacy of sonoporation in a sheep model. Dr. Bakhos is a former post-doctoral fellow at the House Institute and a frequent collaborator with John Galvin, PhD (current cochlear implant researcher at HIF). Dr. Bakhos chose to work with sheep after his team demonstrated similar physiology and range of acoustic frequencies between the sheep and human ear (Trinh et al., 2022). Thus far, he has demonstrated the safety of sonoporation in the sheep model. In the six sheep his team treated, he observed no hearing loss or dangerously increased temperature in the inner ear – a standard concern when ultrasound is involved (Kerneis et al., 2023). He is now focused on the second part of the study – comparing the efficacy of standard trans-tympanic injection to sonoporation. His team has also published a major review of sonoporation and inner ear drug delivery (Micaletti et al., 2024).
The Development Grant from HIF allowed Dr. Bakhos to begin this vital research, and he has since applied for further funding. As such, Dr. Bakhos’s project is a wonderful example of collaboration with and support from HIF, leading to high-impact global research at the cutting edge of hearing science.
