It’s not quite as simple as CRISPR ear drops, but it’s pretty close. The experiments in Chen’s lab at the Massachusetts Eye & Ear Infirmary involve mice who share a genetic defect that humans have that causes gradual hearing loss. Actually, doctors aren’t clear on what physiological changes to ear cells these genetic errors actually cause. “With CRISPR we can just do direct delivery, one shot delivery, and the correction is permanent,” says Chen. These are injected into a mouse’s inner ear, home to delicate hair cells that sense vibrations and send messages to the brain. In the best cases, Chen and Liu have reported, mice treated with CRISPR retain significant hearing at two months of age.
If the CRISPR injections can prevent that, Chen says, “We can move the endeavors into humans.” That’s another advantage of working in China.