For Americans who are afflicted with some type of hearing loss, the options for restoring their hearing have focused solely on assistive devices such as hearing aids and cochlear implants. Now, promising research at major academic medical centers such as Stanford and the University of Southern California (USC) is employing the use of stem cells to develop therapies that may help cure hearing loss.
For the 20 percent of Americans who are afflicted with some type of hearing loss, the options for restoring their hearing have focused solely on assistive devices such as hearing aids and cochlear implants. Unfortunately, an actual cure for hearing loss remains out of reach. Why? Because the hair cells that transmit sound from the cochlea of the inner ear to the brain cannot be repaired, once they have been damaged. Now, promising research at major academic medical centers such as Stanford and the University of Southern California (USC) is employing the use of stem cells to develop therapies that may help cure hearing loss.
Stem cells are cells that can be reprogrammed at the molecular level to grow into specific tissues and organs of the body. This regenerative quality has lead researchers to be optimistic about future applications. Current stem cell research is looking to cure or develop treatments for many other chronic, debilitating diseases and conditions, such as Parkinson's disease, diabetes, and spinal cord injury. Investigators at Stanford have been working over the last ten years on re-building the sound-sensing apparatus of the inner ear. By mimicking the steps involved in the formation of embryonic mouse ears, Stanford scientists have produced stem cells in the laboratory that look and act very much like hair cells in the human inner ear.
A promising development is where stem cells can be cultivated: cells taken from a patient’s own skin that have been genetically reprogrammed to revert back to stem cells. This breakthrough process represents a major opportunity to eventually treat a patient with his or her own cells. Currently, the Stanford team is working toward producing human hair cells for the first time in a culture dish. If they can generate hair cells in the millions, it could lead to significant scientific and clinical advances along the path to curing deafness in the future.
While the use of stem cells to replace an individual's own hair cells is still in early development, researchers at USC are exploring ways to use stem cells to prevent hearing loss. Similar to what is happening at Stanford, scientists are studying ways to reprogram skin cells into inner ear cells. The difference is, the researchers at USC will then put these reprogrammed cells into a robotic screening machine, allowing the scientists to test thousands of drugs at a time. The goal is to find drugs that protect against or reverse hearing damage, and that stimulate regeneration.