title: In vitro proliferation and differentiation of human mesenchymal stem cells on hydroxyapatite versus human demineralised bone matrix with and without osteogenic protein-1.
abstract: BACKGROUND
  Allografting is currently used in lower limb reconstruction surgery. Demineralised bone matrix (DBM) is more osteoinductive compared with allografts but lacks mechanical strength. Osteogenic protein-1 (OP-1) can improve the osteoinductivity of the allograft, however recent reports indicate significant allograft resorption when it is combined with OP-1.
  
  
  OBJECTIVE
  Our hypothesis was that hydroxyapatite (HA) with human-mesenchymal stem cells (h-MSCs) and OP-1 (HA+h-MSCs+OP-1) has similar osteoinductive properties to human-DBM+h-MSCs. The objective was to evaluate h-MSC proliferation (by tritiated thymidine incorporation, total DNA Hoechst 33258 and scanning electron microscopy) and osteogenic differentiation (from alkaline phosphatase activity) in human demineralised bone matrix (h-DBM) and HA, with or without OP-1.
  
  
  RESULTS
  H-MSC proliferation on HA+OP-1 was significantly higher compared with that on HA at all time points (p < 0.05) and compared with DBM alone [day 1, (198.4 vs 95.4) p = 0.042; day 14 (286.1 vs 119.9), p < 0.001]. H-MSC proliferation was higher in DBM+OP-1, at all time points compared with HA+OP-1 but the difference was not statistically significant (p > 0.05). H-MSC differentiation was significantly higher in HA+OP-1 compared with HA (p < 0.05) but not significantly different from diffferentiation on DBM alone (p > 0.05). Differentiation was significantly higher on DBM+OP-1 at all time points compared with HA (p < 0.05) and with HA+OP-1 [day 1, (21.1 vs 10.1) (p = 0.03); day 7 (39.4 vs 7.1) (p < 0.01); day 14 (40.2 vs 14.4) (p < 0.001)].
  
  
  CONCLUSIONS
  When HA+h-MSCs is combined with OP-1 in vitro its osteogenic potential is similar to that of DBM+h-MSCs alone which may be adequate for non-weight-bearing applications. Mechanical testing however is of great importance for weight-bearing applications and the in vivo testing of the composite graft HA+h-MSCs+OP-1 vs DBM+h-MSCs is recommended.
authors.affiliation: Academic Unit of Trauma and Orthopaedic Surgery, Clarendon Wing, Leeds General Infirmary, Leeds, UK. etsiridis@doctors.org.uk
authors.forename: Eleftherios
authors.initials: E
authors.lastname: Tsiridis
authors.forename: Zubier
authors.initials: Z
authors.lastname: Ali
authors.forename: Amit
authors.initials: A
authors.lastname: Bhalla
authors.forename: Zakareya
authors.initials: Z
authors.lastname: Gamie
authors.forename: Manolis
authors.initials: M
authors.lastname: Heliotis
authors.forename: Neelam
authors.initials: N
authors.lastname: Gurav
authors.forename: Sanjukta
authors.initials: S
authors.lastname: Deb
authors.forename: Lucy
authors.initials: L
authors.lastname: DiSilvio
mesh_terms: D000328:Adult; D000469:Alkaline Phosphatase / Q000378:metabolism; D018775:Bone Demineralization Technique; D001857:Bone Matrix / Q000166:cytology*; D055419:Bone Morphogenetic Protein 7 / Q000494:pharmacology*; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D017886:Durapatite / Q000494:pharmacology*; D006801:Humans; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D008855:Microscopy, Electron, Scanning
chemical_list: D055419:Bone Morphogenetic Protein 7; D017886:Durapatite; D000469:Alkaline Phosphatase