title: Bioactive copper-doped glass scaffolds can stimulate endothelial cells in co-culture in combination with mesenchymal stem cells.
abstract: Bioactive glass (BG) scaffolds are being investigated for bone tissue engineering applications because of their osteoconductive and angiogenic nature. However, to increase the in vivo performance of the scaffold, including enhancing the angiogenetic growth into the scaffolds, some researchers use different modifications of the scaffold including addition of inorganic ionic components to the basic BG composition. In this study, we investigated the in vitro biocompatibility and bioactivity of Cu2+-doped BG derived scaffolds in either BMSC (bone-marrow derived mesenchymal stem cells)-only culture or co-culture of BMSC and human dermal microvascular endothelial cells (HDMEC). In BMSC-only culture, cells were seeded either directly on the scaffolds (3D or direct culture) or were exposed to ionic dissolution products of the BG scaffolds, kept in permeable cell culture inserts (2D or indirect culture). Though we did not observe any direct osteoinduction of BMSCs by alkaline phosphatase (ALP) assay or by PCR, there was increased vascular endothelial growth factor (VEGF) expression, observed by PCR and ELISA assays. Additionally, the scaffolds showed no toxicity to BMSCs and there were healthy live cells found throughout the scaffold. To analyze further the reasons behind the increased VEGF expression and to exploit the benefits of the finding, we used the indirect method with HDMECs in culture plastic and Cu2+-doped BG scaffolds with or without BMSCs in cell culture inserts. There was clear observation of increased endothelial markers by both FACS analysis and acetylated LDL (acLDL) uptake assay. Only in presence of Cu2+-doped BG scaffolds with BMSCs, a high VEGF secretion was demonstrated by ELISA; and typical tubular structures were observed in culture plastics. We conclude that Cu2+-doped BG scaffolds release Cu2+, which in turn act on BMSCs to secrete VEGF. This result is of significance for the application of BG scaffolds in bone tissue engineering approaches.
authors.affiliation: Department of Plastic and Hand Surgery, University of Erlangen-Nürnberg, Erlangen, Germany; Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Yeddumailaram, Telangana, India.
authors.forename: Subha N
authors.initials: SN
authors.lastname: Rath
authors.affiliation: Department of Plastic and Hand Surgery, University of Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Brandl
authors.affiliation: Department of Plastic and Hand Surgery, University of Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hiller
authors.affiliation: Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen- Nürnberg, Erlangen, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Hoppe
authors.affiliation: Department for Functional Materials in Medicine and Dentistry, Universtiy of Würzburg, Würzburg, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Gbureck
authors.affiliation: Department of Plastic and Hand Surgery, University of Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Raymund E
authors.initials: RE
authors.lastname: Horch
authors.affiliation: Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen- Nürnberg, Erlangen, Germany.
authors.forename: Aldo R
authors.initials: AR
authors.lastname: Boccaccini
authors.affiliation: Department of Plastic and Hand Surgery, University of Erlangen-Nürnberg, Erlangen, Germany; Department of Hand, Plastic and Reconstructive Surgery - Burn Center, University of Heidelberg, Ludwigshafen, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kneser
mesh_terms: D018786:Bone Substitutes / Q000737:chemistry / Q000494:pharmacology*; D002454:Cell Differentiation; D018920:Coculture Techniques; D003300:Copper / Q000737:chemistry / Q000494:pharmacology*; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D005898:Glass / Q000737:chemistry; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D055806:Microvessels / Q000166:cytology; D010012:Osteogenesis; D023822:Tissue Engineering / Q000379:methods; D054457:Tissue Scaffolds / Q000737:chemistry*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D018786:Bone Substitutes; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D003300:Copper