title: Combined effect of strontium and zoledronate on hydroxyapatite structure and bone cell responses.
abstract: The influence of the simultaneous presence of the two inhibitors of bone degradation, strontium and zoledronate, on the direct synthesis of hydroxyapatite was explored in the range of Sr concentration up to 50 atom% at two different bisphosphonate concentrations (ZOL7 and ZOL14). The results of structural analysis indicated that HA can be obtained as a single crystalline phase up to a Sr concentration in solution of 20 and 10 atom% within the ZOL7 and ZOL14 series respectively. Both Sr substitution and ZOL incorporation affect the length of the coherently scattering crystalline domains and the dimensions of HA nanocrystals. At greater Sr content, XRD full profile fitting data indicate that zoledronate provokes the segregation of Sr in two crystalline apatitic phases, at different strontium content. Co-cultures of osteoblast-like MG63 cells and human osteoclast show that ZOL displays a greater inhibitory influence than Sr on osteoclast proliferation and activity. On the other hand, the results obtained on osteoblast surnatant and on gene expression indicate that Sr exerts a greater promotion on osteoblast proliferation and differentiation. The co-presence of Sr and ZOL has a combined effect on the differentiation markers, so that HA containing about 4 wt% ZOL and 4 Sr atom%, and even more HA containing about 4 wt% ZOL and 8 Sr atom%, result the best compromise for osteoblast promotion and osteoclast inhibition.
authors.affiliation: Department of Chemistry "G. Ciamician", University of Bologna, Bologna, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Boanini
authors.affiliation: Laboratory of Preclinical and Surgical Studies, Codivilla-Putti Research Institute, Rizzoli Orthopaedic Institute, Bologna, Italy; Department Rizzoli RIT, Rizzoli Orthopedic Institute-IOR, Laboratory of Biocompatibility, Technological Innovations and Advanced Therapies, Bologna, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Torricelli
authors.affiliation: ISOF-CNR, C/o Department of Chemistry "G. Ciamician", Bologna, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Gazzano
authors.affiliation: Laboratory of Preclinical and Surgical Studies, Codivilla-Putti Research Institute, Rizzoli Orthopaedic Institute, Bologna, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Della Bella
authors.affiliation: Laboratory of Preclinical and Surgical Studies, Codivilla-Putti Research Institute, Rizzoli Orthopaedic Institute, Bologna, Italy; Department Rizzoli RIT, Rizzoli Orthopedic Institute-IOR, Laboratory of Biocompatibility, Technological Innovations and Advanced Therapies, Bologna, Italy.
authors.forename: Milena
authors.initials: M
authors.lastname: Fini
authors.affiliation: Department of Chemistry "G. Ciamician", University of Bologna, Bologna, Italy. Electronic address: adriana.bigi@unibo.it.
authors.forename: Adriana
authors.initials: A
authors.lastname: Bigi
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D018920:Coculture Techniques; D004164:Diphosphonates / Q000737:chemistry / Q000494:pharmacology*; D017886:Durapatite / Q000737:chemistry*; D006801:Humans; D007093:Imidazoles / Q000737:chemistry / Q000494:pharmacology*; D053758:Nanoparticles / Q000737:chemistry; D010006:Osteoblasts / Q000737:chemistry / Q000187:drug effects; D010011:Osteocytes / Q000187:drug effects* / Q000378:metabolism; D013324:Strontium / Q000737:chemistry / Q000494:pharmacology*; D000077211:Zoledronic Acid
chemical_list: D004164:Diphosphonates; D007093:Imidazoles; D000077211:Zoledronic Acid; D017886:Durapatite; D013324:Strontium
keywords: Bisphosphonates; Co-cultures; Hydroxyapatite; Osteoblast; Osteoclast; Strontium