Statins and hearing

Statins are a class of drugs that are widely used for the treatment of hyperlipidemia and the prevention of heart attack and stroke. These drugs inhibit the rate-limiting step in the synthesis of cholesterol, HMG-CoA reductase. In addition, statins have effects unrelated to cholesterol, stemming from the non-cholesterol synthesizing arms of the HMG-CoA reductase pathway and the regulation of gene expression. In multiple studies, depending on the cell type and type of statin, statins have been shown to increase antioxidant activity, decrease inflammatory mediators and alleviate damage to blood vessels. When the cochlea experiences stresses that can lead to damage and to hearing loss, increases in reactive oxygen species, inflammatory mediators and blood vessel damage are generally observed. This review summarizes the published in vitro, animal, and clinical studies that examine effects of statins on damaged cochlear structures and on hearing loss. Preclinical results show largely protective effects of statins and raise the possibility that statins will find a place in interventions for hearing loss. Thus far, however, clinical studies and trials are rare and inconsistent. Given the volumes of information on pharmacology and toxicology that is known about statins from their more than 30 years in medicine, relative safety of the drugs and their broad accessibility, the time is ripe for more well-controlled, prospective, and focused clinical trials to determine whether statins might be repurposed for the protection or repair of hearing.