When Lama Khalaily peers through a microscope at living inner ear tissue, she sees something scientists once thought impossible: cells in the human cochlea that might be capable of healing themselves.
Khalaily, a doctoral student at Tel Aviv University, is part of a research team that has discovered a rare group of cells in the inner ear that can transform into sound-detecting hair cells—the same cells that, when damaged in humans, cause permanent hearing loss. The finding, published in the journal Science Advances, offers real hope for the millions of people worldwide whose hearing never comes back once it's gone.
"In tissues long considered incapable of regeneration, such as the cochlea of the inner ear, there is in fact a hidden regenerative capacity," said Prof. Karen Avraham, who led the study. "This is a first but significant step toward a deeper understanding of regeneration in the auditory system."
Here's why this matters: The inner ear contains tiny hair cells that catch sound vibrations and turn them into electrical signals the brain can understand. When these cells die—whether from loud noise, aging, or certain medications—they never grow back in humans. Unlike some animals, like birds and fish, mammals cannot regenerate these cells, making hearing loss permanent. Currently, there is no cure. People can only manage it with hearing aids or cochlear implants.
The Tel Aviv team wanted to find out if that limitation could be overcome. Using powerful live-imaging technology and single-cell analysis methods, the researchers focused on supporting cells—neighbor cells that normally just sit beside the hair cells and don't change. They then blocked a communication pathway called Notch, which controls how cells develop early in life.
The results were striking. A small subset of supporting cells, which the researchers named "transdifferentiating Deiters' cells" or tDCs, began transforming into hair cells. These rare cells have unique genetic and molecular features that allow them to respond to the right signals and start the healing process—something the surrounding cells cannot do.
The researchers emphasize that this doesn't mean a hearing loss cure is around the corner. Right now, only a tiny fraction of cells have this ability, and scientists still need to figure out how to activate the same potential in many more cells. But the discovery provides a roadmap for how it might eventually work—using genetic and epigenetic treatments to wake up the body's own repair mechanisms rather than relying solely on devices.
"The major challenge now is to understand how this ability can be expanded and activated in additional cells," Avraham said. "If we succeed in doing this, we may lay the foundation for the development of innovative biological treatments that restore hearing, rather than merely compensate for its loss."
The study was a collaboration between researchers at Tel Aviv University's Gray Faculty of Medical and Health Sciences and Wise Faculty of Life Sciences, along with Dr. Litao Tao from Creighton University in Omaha. For Khalaily, who spearheaded the research as a doctoral student, it's a promising beginning to what may become a entirely new field of medicine.