Life-saving antibiotics may be one of the single greatest contributions to the scientific community since the creation of Penicillin in 1928 by Alexander Fleming. Responsible for saving millions of lives on an annual basis, the positives regarding antibiotics cannot be understated. But like all medication, side-effects can occur when taking antibiotics ranging from nausea, headaches, and one ailment that may be surprising to some: antibiotic-induced hearing loss. However, life-saving antibiotics may be required to treat a patient from a potentially fatal illness. How does one treat illnesses with antibiotics while attempting to limit hearing damage in patients? A new study in mice and inflammation may hold the answer.
Some antibiotics are ototoxic, or “toxic to the ear”, with the potential to damage your cochlea, auditory nerve, and even the vestibular system responsible for maintaining your balance. These ototoxic antibiotics fall in a class of widely used antibiotics referred to as “Aminoglycosides”, which work by reducing bacterial cell’s ability to create proteins and rendering them ineffective, and are used much more commonly than one might think. Gentamicin, streptomycin, and neomycin are all examples of aminoglycosides and are used to treat all sorts of ailments, ranging from Endocarditis to minor skin infections.
Though antibiotics are responsible for saving millions of lives, inflammation from infection can leave your sensory hair cells susceptible to toxicity from ototoxic medication, resulting in a worsening of tinnitus or temporary hearing loss as a side effect.
Conducted by Dr. Peter Steyger, PhD, and his team at Creighton University in Nevada, this 2019 study found that inflammation due to infection made fragile sensory hair cells responsible for registering sound more susceptible to the antibiotics toxic side effects, concluding “Because of the inflammation, the ion channels in the sensory hair cells of the inner ear become more permeable to antibiotics which then increases the cells’ sensitivity to the drugs’ toxic effects.”
That’s not the only important discovery Dr. Steyger and his team had found though. After testing Gentamicin, an aminoglycoside antibiotic, on mice, Steyger’s team had discovered hopeful news. TRPV1, a protein involved in ion channels, allowed the drug’s toxic side effects into the sensory hair cells, while mice that were bred without working TRPV1 were protected from hearing loss caused by Gentamicin.
Why is Creighton University’s study so important? Dr. Steyger explains “This gives us confidence that otoprotective drugs can be developed to prevent this type of hearing loss”, predicting future hope in reducing antibiotic-induced hearing loss. With this future in mind, Creighton’s Translational Hearing Center has a new mission in attempting the development of druggable targets to develop otoprotectants, such as sodium thiosulfate, which is used to protect hearing from treatments such as chemotherapy. Thanks to Dr. Steyger and his team’s discovery, the medical community has gained new insight into the damage that these lifesaving antibiotics can do to hearing health and has charted a path forward for the future.