title: Differences in otosclerotic and normal human stapedial osteoblast properties are normalized by alendronate in vitro.
abstract: OBJECTIVE
  Identify and compare phenotypic properties of osteoblasts from patients with otosclerosis (OSO), normal bones (HOB), and normal stapes (NSO) to determine a possible cause for OSO hypermineralization and assess any effects of the bisphosphonate, alendronate.
  
  
  METHODS
  OSO (n = 11), NSO (n = 4), and HOB (n = 13) cultures were assayed for proliferation, adhesion, mineralization, and gene expression with and without 10(-10)M-10(-8)M alendronate.
  
  
  METHODS
  Academic hospital.
  
  
  METHODS
  Cultures were matched for age, sex, and passage number. Cell attachment and proliferation + alendronate were determined by Coulter counting cells and assaying tritiated thymidine uptake, respectively. At 7, 14, and 21 days of culture + alendronate, calcium content and gene expression by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) were determined.
  
  
  RESULTS
  OSO had significantly more cells adhere but less proliferation than NSO or HOB. Calcification was significantly increased in OSO compared to HOB and NSO. NSO and HOB had similar cell adhesion and proliferation rates. A dose-dependent effect of alendronate on OSO adhesion, proliferation, and mineralization was found, resulting in levels equal to NSO and HOB. All cultures expressed osteoblast-specific genes such as RUNX2, alkaline phosphatase, type I collagen, and osteocalcin. However, osteopontin was dramatically reduced, 9.4-fold at 14 days, in OSO compared to NSO. Receptor activator of nuclear factor κB ligand/osteoprotegerin (RANKL/OPG), important in bone resorption, was elevated in OSO with decreased levels of OPG levels. Alendronate had little effect on gene expression in HOB but in OSO increased osteopontin levels and decreased RANKL/OPG.
  
  
  CONCLUSIONS
  OSO cultures displayed properties of hypermineralization due to decreased osteopontin (OPN) and also had increased RANKL/OPG, which were normalized by alendronate.
authors.affiliation: University of Connecticut Health Center, Farmington, Connecticut, USA.
authors.forename: Gloria
authors.initials: G
authors.lastname: Gronowicz
authors.affiliation: University of Connecticut Health Center, Farmington, Connecticut, USA.
authors.forename: Yvonne L
authors.initials: YL
authors.lastname: Richardson
authors.affiliation: University of Connecticut Health Center, Farmington, Connecticut, USA.
authors.forename: John
authors.initials: J
authors.lastname: Flynn
authors.affiliation: Yale University School of Medicine, New Haven, Connecticut, USA.
authors.forename: John
authors.initials: J
authors.lastname: Kveton
authors.affiliation: Hartford Hospital, Hartford, Connecticut, USA.
authors.forename: Marc
authors.initials: M
authors.lastname: Eisen
authors.affiliation: University of Connecticut Health Center, Farmington, Connecticut, USA.
authors.forename: Gerald
authors.initials: G
authors.lastname: Leonard
authors.affiliation: Hartford Hospital, Hartford, Connecticut, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Aronow
authors.affiliation: University of Connecticut Health Center, Farmington, Connecticut, USA.
authors.forename: Craig
authors.initials: C
authors.lastname: Rodner
authors.affiliation: University of Connecticut Health Center, Farmington, Connecticut, USA parham@neuron.uchc.edu.
authors.forename: Kourosh
authors.initials: K
authors.lastname: Parham
mesh_terms: D000328:Adult; D019386:Alendronate / Q000494:pharmacology*; D050071:Bone Density Conservation Agents / Q000494:pharmacology*; D002113:Calcification, Physiologic / Q000187:drug effects*; D016022:Case-Control Studies; D002448:Cell Adhesion / Q000187:drug effects; D018929:Cell Culture Techniques; D049109:Cell Proliferation / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010006:Osteoblasts / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D010040:Otosclerosis / Q000209:etiology / Q000473:pathology* / Q000628:therapy; D013199:Stapes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology
chemical_list: D050071:Bone Density Conservation Agents; D019386:Alendronate
keywords: bisphosphonates; deafness; hypermineralization; osteoblasts; otosclerosis