title: Dexamethasone eluting cochlear implant: Histological study in animal model.
abstract: OBJECTIVE
  New cochlear implant (CI) designs and developments in implantation techniques have revolutionized the management of hearing loss. However, cochlear implantation still has some disadvantages, such as its potential to initiate an inflammatory response that may lead to further hair cell damage. Recent topics of investigation have been the effect of glucocorticoids on inflammatory tissue response reduction, glucocorticoid dosage levels, and drug-delivery methods. In the present study, dexamethasone delivery via a drug-eluting CI was evaluated histologically through assessing inflammatory cell infiltration.
  
  
  METHODS
  Thirty healthy, adult male guinea pigs were included and randomly assigned to one of three surgical groups that underwent cochleostomy of the basal turn. The experimental group (Group 1) of 12 animals were implanted with a dexamethasone-loaded silicone elastomer shaped like a CI electrode. The primary control group (Group 2) of 12 animals were implanted with a simple CI (non-eluting). A second control group (Group 3) of six animals underwent cochleostomy only. Inflammatory responses were compared between groups by evaluating inflammatory cell infiltration in inner-ear specimens at days 3 and 13.
  
  
  RESULTS
  The Mann‐Whitney test revealed reduction in most of the inflammatory indices in Group 1 compared with Group 2. This was significant for fibrocyte, macrophage, and giant cell infiltration at day 3 as well as lymphocyte, macrophage infiltration, and capillary formation at day 13.
  
  
  CONCLUSIONS
  This study showed some attenuation in inflammatory response following insertion of a dexamethasone-eluting CI, suggesting that it could be a route for local drug delivery into the cochlea.
authors.affiliation: ENT-Head and Neck Research Center and Department, Hazrat Rasool Akram Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Farhadi
authors.forename: Maryam
authors.initials: M
authors.lastname: Jalessi
authors.forename: Pirooz
authors.initials: P
authors.lastname: Salehian
authors.forename: Farhid Farahmand
authors.initials: FF
authors.lastname: Ghavi
authors.forename: Hesamedin
authors.initials: H
authors.lastname: Emamjomeh
authors.forename: Hamid
authors.initials: H
authors.lastname: Mirzadeh
authors.forename: Mohammad
authors.initials: M
authors.lastname: Imani
authors.forename: Claude
authors.initials: C
authors.lastname: Jolly
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage*; D002196:Capillaries / Q000187:drug effects / Q000473:pathology; D020099:Coated Materials, Biocompatible; D003051:Cochlea / Q000187:drug effects / Q000473:pathology / Q000601:surgery; D003054:Cochlear Implants; D003907:Dexamethasone / Q000008:administration & dosage*; D004567:Electrodes, Implanted; D005347:Fibroblasts / Q000187:drug effects / Q000473:pathology; D005549:Foreign-Body Reaction / Q000473:pathology*; D015743:Giant Cells, Foreign-Body / Q000187:drug effects / Q000473:pathology; D006168:Guinea Pigs; D018655:Lymphocyte Count; D008264:Macrophages / Q000187:drug effects / Q000473:pathology; D008297:Male; D012826:Silicone Elastomers
chemical_list: D000893:Anti-Inflammatory Agents; D020099:Coated Materials, Biocompatible; D012826:Silicone Elastomers; D003907:Dexamethasone