title: Systemically administered human growth hormone improves initial implant stability: an experimental study in the rabbit.
abstract: OBJECTIVE
  This study was an investigation to determine whether human growth hormone (hGH) continuously administered to rabbits may improve implant integration in bone.
  
  
  METHODS
  Thirty-two commercially pure titanium (c.p. Ti) implants were inserted in the tibiae of 16 rabbits. Human growth hormone (0.3 U/kg/d) or sodium chloride (NaCl) was administered by subcutaneous pumps. Insulin-like growth factor-1 (IGF-1) levels in blood were measured. Two biomechanical tests were performed: (1) every second week resonance frequency analysis (RFA) was used to investigate implant stability or stiffness at the interface and, after 8 weeks of follow-up, (2) removal torque (a measure of implant integration and stability) was registered. Further evaluation was performed by dual energy x-ray analysis (DEXA), to evaluate bone mineral density, and histomorphometric analysis of tissue-to-implant integration on undecalcified cut and ground sections.
  
  
  RESULTS
  A difference in implant stability was detected with the RFA technique after 2 weeks and 8 weeks in favor of the hGH-treated rabbits. No significant differences were detected with removal torque, DEXA, and histomorphometric measurements. The blood test demonstrated antibody development in the rabbits treated with hGH after 4 weeks.
  
  
  CONCLUSIONS
  Growth hormone has an initial beneficial effect on implant integration; however, owing to rapid antibody formation, this study did not demonstrate whether this effect remains in the long term.
authors.affiliation: Department of Biomaterials/Handicap Research, Gothenburg University, Box 412, S-405 30, Gothenburg, Sweden. victoria.franke-stenport@hkf.gu.se
authors.forename: V F
authors.initials: VF
authors.lastname: Stenport
authors.forename: B
authors.initials: B
authors.lastname: Olsson
authors.forename: P
authors.initials: P
authors.lastname: Morberg
authors.forename: J
authors.initials: J
authors.lastname: Törnell
authors.forename: C B
authors.initials: CB
authors.lastname: Johansson
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D000906:Antibodies / Q000097:blood; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000187:drug effects; D001857:Bone Matrix / Q000187:drug effects / Q000648:ultrastructure; D001842:Bone and Bones / Q000187:drug effects* / Q000601:surgery / Q000648:ultrastructure; D015921:Dental Implants; D005500:Follow-Up Studies; D019382:Human Growth Hormone / Q000008:administration & dosage / Q000276:immunology / Q000627:therapeutic use*; D006801:Humans; D015918:Infusion Pumps, Implantable; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D023421:Models, Animal; D016348:Osseointegration; D010521:Periosteum / Q000187:drug effects / Q000648:ultrastructure; D011817:Rabbits; D013016:Sound; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013977:Tibia; D014025:Titanium; D019415:Torque
chemical_list: D000906:Antibodies; D015921:Dental Implants; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D014025:Titanium