Growth factor-eluting cochlear implant electrode: impact on residual auditory function, insertional trauma, and fibrosis

Abstract

Background: A cochlear implant (CI) is an artificial hearing device that can replace a damaged cochlea. The present study examined the use of growth factor-eluting gelatin hydrogel coatings on the electrodes to minimize inner ear trauma during electrode insertion. Insulin-like growth factor 1 (IGF1) and/or hepatocyte growth factor (HGF) were chosen as the agents to be administered. Methods: Silicone CI electrode analogs were prepared and coated with gelatin hydrogels. Adsorption/release profile of the hydrogel was measured using

Middle‐ear dexamethasone delivery via ultrasound microbubbles attenuates noise‐induced hearing loss

“…Outer hair cells' (OHCs) survival rates were calculated using the following formula: OHC survival rate% = 100 × [(the number of OHCs present in the examined specimens) / (the number of examined specimens) / 3] …”

Recent advances in local drug delivery to the inner ear

“…748 The drug release kinetic frompolymer coated electrodes was evaluated in vitro. The drug 749 release can be sustained up to several months (Astolfi et al, 2014, Kikkawa et al, 2014, 750 Wrzeszcz et al, 2014or years (Krenzlin et al, 2012) (Pararas et al, 2011). A critical issue for using this device consists in obtaining an 773 overall size consistent with surgical implantation into the mastoid cavity behind the ear.…”

“…The electrode can be embedded within a polymeric matrix containing a 733 drug that will be released into the scala tympani for a prolonged period of time (ideally 734 several months up to years) (Krenzlin et al, 2012). Kikkawa et al, (2014) (Krenzlin et al, 2012), 743 Poly(L-lactide) and poly(4-hydroxybutyrate) could also be used as potential coating matrices 744 for cochlear implants (Ceschi et al, 2014). Interestingly, Bohl et al, (2012)showed that a 745 combination of poly(4-hydroxybutyrate) and silicone coating resulted in a biphasic 746 dexamethasone release: initial burst release from the first polymer to treat the acute 747 response and a slow release from the silicone to prevent long-term inflammatory reactions.…”

Targeting Cholesterol Homeostasis to Fight Hearing Loss: A New Perspective

“…Other trophic factors have shown effectiveness in modulating inner ear protection and repair, such as of insulin-like growth factor 1 (IGF-1). IGF-1 is effective in the protection from electrode trauma insertion in the guinea pig and in the recovery from sudden hearing loss in humans (Kikkawa et al, 2014 ; Nakagawa et al, 2014 ). This is promising, since, in men and mice, IGF-1 deficiency causes SNHL (Varela-Nieto et al, 2013 ) but more trials are needed.…”