Strontium-releasing fluorapatite glass-ceramic scaffolds: Structural characterization and in vivo performance.

Autor: Denry I; Iowa Institute for Oral Health Research, University of Iowa College of Dentistry, Iowa City, Iowa, United States; Department of Prosthodontics, University of Iowa College of Dentistry, Iowa City, Iowa, United States. Electronic address: Isabelle-Denry@uiowa.edu., Goudouri OM; Iowa Institute for Oral Health Research, University of Iowa College of Dentistry, Iowa City, Iowa, United States., Fredericks DC; Iowa Spine Research Laboratory, Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States., Akkouch A; Iowa Institute for Oral Health Research, University of Iowa College of Dentistry, Iowa City, Iowa, United States., Acevedo MR; Department of Radiology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, United States., Holloway JA; Department of Prosthodontics, University of Iowa College of Dentistry, Iowa City, Iowa, United States.
Jazyk: angličtina
Zdroj: Acta biomaterialia [Acta Biomater] 2018 Jul 15; Vol. 75, pp. 463-471. Date of Electronic Publication: 2018 May 30.
DOI: 10.1016/j.actbio.2018.05.047
Abstrakt: There is increasing interest in biodegradable ceramic scaffolds for bone tissue engineering capable of in situ delivery of ionic species favoring bone formation. Strontium has been shown to be osteogenic, but strontium-containing drugs such as strontium ranelate, used in Europe for the treatment of osteoporosis, are now restricted due to clinical evidence of systemic effects. By doping fluorapatite-based glasses with strontium, we developed ceramic scaffolds with fully interconnected macroporosity and cell size similar to that of cancellous bone, that are also capable of releasing strontium. The crystallization behavior, investigated by XRD and SEM, revealed the formation of akermanite and fluorapatite at the surface of strontium-free glass-ceramic scaffolds, and strontium-substituted fluorapatite at the surface of the strontium-doped scaffolds. At 8 weeks after implantation in a rat calvarial critical size defect, scaffolds doped with the highest amount of strontium led to the highest mineral apposition rate. A significantly higher amount of newly-formed bone was found with the strontium-free glass-ceramic scaffold, and possibly linked to the presence of akermanite at the scaffold surface. We demonstrate by energy dispersive XRF analyses of skull sections that strontium was present in newly formed bone with the strontium-doped scaffolds, while a significant amount of fluorine was incorporated in newly formed bone, regardless of composition or crystallization state.
Statement of Significance: The present work demonstrates the in vivo action of strontium-containing glass-ceramic scaffolds. These bone graft substitutes are targeted at non load-bearing bone defects. Results show that strontium is successfully incorporated in newly formed bone. This is associated with a significantly higher Mineral Apposition Rate. The benefits of in situ release of strontium are demonstrated. The broader scientific impact of this works builds on the concept of resorbable ceramic scaffolds as reservoirs of ionic species capable of enhancing bone regeneration.
(Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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