title: Sex dependent regulation of osteoblast response to implant surface properties by systemic hormones.
abstract: BACKGROUND
  Osseointegration depends on the implant surface, bone quality and the local and systemic host environment, which can differ in male and female patients. This study was undertaken in order to determine if male and female cells respond differently to titanium surfaces that have micron-scale roughness and if interactions of calciotropic hormones [1α,25(OH)2D3 and 17β-oestradiol (E2)] and microstructured surfaces on osteoblasts are sex dependent.
  
  
  METHODS
  Osteoblasts from 6-week old Sprague-Dawley rats were cultured on tissue culture polystyrene (TCPS) or on titanium (Ti) disks with two different surface topographies, a smooth pretreated (PT) surface and a coarse grit-blasted/acid-etched (SLA) surface, and treated with 1α,25(OH)2D3, E2, or E2 conjugated to bovine serum albumin (E2-BSA).
  
  
  RESULTS
  Male and female cells responded similarly to Ti microstructure with respect to cell number and levels of osteocalcin, transforming growth factor-β1, osteoprotegerin and prostaglandin E2 in their conditioned media, exhibiting a more differentiated phenotype on SLA than on PT or TCPS. E2 and E2-BSA increased differentiation and local factor production, an effect that was microstructure dependent and found only in female osteoblasts. 1α,25(OH)2D3 increased osteoblast differentiation and local factor production in female and male cells, but the effect was more robust in male cells.
  
  
  CONCLUSIONS
  Male and female rat osteoblasts respond similarly to surface microstructure but exhibit sexual dimorphism in substrate-dependent responses to systemic hormones. Oestrogen affected only female cells while 1α,25(OH)2D3 had a greater effect on male cells. These results suggest that successful osseointegration in males and females may depend on the implant surface design and correct levels of calciotropic hormones.
authors.affiliation: Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA, USA. barbara.boyan@bme.gatech.edu.
authors.forename: Rene
authors.initials: R
authors.lastname: Olivares-Navarrete
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Hyzy
authors.forename: Reyhaan A
authors.initials: RA
authors.lastname: Chaudhri
authors.forename: Ge
authors.initials: G
authors.lastname: Zhao
authors.forename: Barbara D
authors.initials: BD
authors.lastname: Boyan
authors.forename: Zvi
authors.initials: Z
authors.lastname: Schwartz