The influence of cholesterol on the motility of cochlear outer hair cells and the motor protein prestin

Abstract

Cholesterol at a concentration of 0.1 mM had no effect on motility. A concentration of 1 mM reduced maximal evoked shortening significantly by 29% in the depolarizing and by 9% in the hyperpolarizing direction. Investigating half activated motor proteins, 1 mM cholesterol reduced movements significantly by 18%, elongations decreased nonsignificantly by 5%.

Susceptibility of outer hair cells to cholesterol chelator 2-hydroxypropyl-β-cyclodextrine is prestin-dependent

“…Prestin is essential for OHC electromotility, structural integrity, and survival 15 28 37 38 . Previous studies have described a variety of cholesterol effects on prestin regulation, including its membrane targeting, oligomerization, and lipid-raft association 21 39 40 , as well as its voltage-dependent motor function 20 41 . These effects can be attributed to changes in physical properties of the biological membrane and/or to direct functional modulation through specific binding 41 .…”

“…Previous studies have described a variety of cholesterol effects on prestin regulation, including its membrane targeting, oligomerization, and lipid-raft association 21 39 40 , as well as its voltage-dependent motor function 20 41 . These effects can be attributed to changes in physical properties of the biological membrane and/or to direct functional modulation through specific binding 41 . Although OHCs are highly susceptible to HPβCD, filipin and TMN did not stain the prestin-containing LM of OHCs.…”

Pharmacogenomics of cisplatin‐induced neurotoxicities: Hearing loss, tinnitus, and peripheral sensory neuropathy

“…Przewoźny et al, 40 suggested that hypertension causes damage to the stria vascularis by reducing cochlear oxygen partial pressure and disrupting the recycling of potassium ions in the cochlea. The relationship with hypercholesterolemia may be related to evidence that cholesterol levels can impair cochlear microcirculation 41 and the function of cochlear outer hair cells 42 . Accordingly, these findings suggest that lowering abnormally high serum lipid levels and adequate control of hypertension may decrease the likelihood or severity of tinnitus.…”

“…The relationship with hypercholesterolemia may be related to evidence that cholesterol levels can impair cochlear microcirculation 41 and the function of cochlear outer hair cells. 42 Accordingly, these findings suggest that lowering abnormally high serum lipid levels and adequate control of hypertension may decrease the likelihood or severity of tinnitus.…”

Effect of statins on hearing function and subjective tinnitus in hyperlipidemic patients

“…Hyperlipidemia is a critical condition that has an effect on both macrovascular and microvascular structures, affecting millions of people across the world, and causing serious consequences when untreated. Hyperlipidemia can have a negative effect on the hearing functions and therefore causes tinnitus since it causes increased blood viscosity, cochlear microcirculation disturbance as a result of decreased NO synthesis in microvascular bed, and reduced motility of cochlear outer hair cells [4,9,10]. Thus, the role of hyperlipidemia frequently encountered diseases, especially in the last periods, such as sudden hearing loss, presbyacusis and tinnitus are studied and various methods of treatment are tried.…”