Researchers from the Stanford School of Medicine have developed a new form of the commonly used antibiotic aminoglycoside. In a recent study, it successfully cured infections in mice without risking hearing loss or kidney damage.
What are aminoglycosides?
For 20 years, aminoglycosides have been the preferred treatment worldwide for many bacterial diseases like pneumonia, peritonitis, and sepsis. Even though there are newer alternatives, aminoglycosides’ effectiveness, lack of need for refrigeration, and low cost make them the go-to drug for severe or unusual infections. They’re often used to in neonatal intensive care units (NICU) to fight deadly infections in babies.
But aminoglycosides can sometimes cause hearing loss by killing the non-regenerating sensory hair cells of the inner ear. These hair cells help convert sounds into electrical signals for the brain. It’s not ideal, but there hasn’t yet been an alternative medication that’s as successful in saving lives. The researchers at Stanford hope to change that.
How does the new drug avoid causing hearing loss?
Previous attempts to eliminate the risk of hearing loss with these antibiotics also blocked the drug’s ability to fight infection. However, Dr. Anthony Ricci, professor of otolaryngology-head and neck surgery at Stanford and co-senior author of the study, had a new idea.
His expertise on the ear’s components and their functions allowed him and the other members of the research team to create a modified version of aminoglycoside, called N1MS, which stops the drug’s molecules from entering the channels of the ear’s sensory hair cells altogether. Instead of removing the infection-killing properties that kill the sensory hair cells, N1MS simply blocks the drug’s access to those cells.
N1MS also eliminates the risk of kidney damage, another common side effect of aminoglycosides. The researchers have not yet examined the reason for this outcome, but they suspect that N1MS is also blocking the access to kidney cells as well.
What’s next for N1MS?
The research team hopes to begin testing N1MS on humans as soon as possible.
As their trials successfully cured mice of bladder infections caused by E. coli without causing hearing loss, they are hopeful that it will prove just as effective for people.
“If we can eventually prevent people from [having their hearing damaged by] taking these antibiotics, in my mind, we will have been successful,” said Ricci. “Our goal is to replace the existing aminoglycosides with ones that aren’t toxic.”