title: Proliferation of ASC-derived endothelial cells in a 3D electrospun mesh: impact of bone-biomimetic nanocomposite and co-culture with ASC-derived osteoblasts.
abstract: BACKGROUND
  Fractures with a critical size bone defect are associated with high rates of delayed- and non-union. The treatment of such complications remains a serious issue in orthopaedic surgery. Adipose derived stem cells (ASCs) combined with biomimetic materials can potentially be used to increase fracture healing. Nevertheless, a number of requirements have to be fulfilled; in particular, the insufficient vascularisation of the bone constructs. Here, the objectives were to study the impact of ASC-derived osteoblasts on ASC-derived endothelial cells in a 3D co-culture and the effect of 40wt% of amorphous calcium phosphate nanoparticles on the proliferation and differentiation of ASC-derived endothelial cells when present in PLGA.
  
  
  METHODS
  Five primary ASC lines were differentiated towards osteoblasts (OBs) and endothelial cells (ECs) and two of them were chosen based on quantitative PCR results. Either a mono-culture of ASC-derived EC or a co-culture of ASC-derived EC with ASC-derived OB (1:1) was seeded on an electrospun nanocomposite of poly-(lactic-co-glycolic acid) and amorphous calcium phosphate nanoparticles (PLGA/a-CaP; reference: PLGA). The proliferation behaviour was determined histomorphometrically in different zones and the expression of von Willebrand Factor (vWF) was quantified.
  
  
  RESULTS
  Independently of the fat source (biologic variability), ASC-derived osteoblasts decelerated the proliferation behaviour of ASC-derived endothelial cells in the co-culture compared to the mono-culture. However, expression of vWF was clearly stronger in the co-culture, indicating further differentiation of the ASC-derived EC into the EC lineage. Moreover, the presence of a-CaP nanoparticles in the scaffold slowed the proliferation behaviour of the co-culture cells, too, going along with a further differentiation of the ASC-derived OB, when compared to pure PLGA scaffolds.
  
  
  CONCLUSIONS
  This study revealed significant findings for bone tissue-engineering. Co-cultures of ASC-derived EC and ASC-derived OB stimulate each other's further differentiation. A nanocomposite with a-CaP nanoparticles offers higher mechanical stability, bioactivity and osteoconductivity compared to mere PLGA and can easily be seeded with pre-differentiated EC and OB.
authors.affiliation: Division of Trauma Surgery, University Hospital Zurich, ZKF, Sternwartstrasse 14, CH-8091 Zurich, Switzerland.
authors.forename: Shuping
authors.initials: S
authors.lastname: Gao
authors.affiliation: Division of Plastic and Hand Surgery, University Hospital Zurich, ZKF, Sternwartstrasse 14, CH-8091 Zurich, Switzerland.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Calcagni
authors.affiliation: Division of Plastic and Hand Surgery, University Hospital Zurich, ZKF, Sternwartstrasse 14, CH-8091 Zurich, Switzerland.
authors.forename: Manfred
authors.initials: M
authors.lastname: Welti
authors.affiliation: Division of Trauma Surgery, University Hospital Zurich, ZKF, Sternwartstrasse 14, CH-8091 Zurich, Switzerland.
authors.forename: Sonja
authors.initials: S
authors.lastname: Hemmi
authors.affiliation: Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093 Zurich, Switzerland.
authors.forename: Nora
authors.initials: N
authors.lastname: Hild
authors.affiliation: Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093 Zurich, Switzerland.
authors.forename: Wendelin J
authors.initials: WJ
authors.lastname: Stark
authors.affiliation: Division of Plastic and Hand Surgery, University Hospital Zurich, ZKF, Sternwartstrasse 14, CH-8091 Zurich, Switzerland.
authors.forename: Gabriella Meier
authors.initials: GM
authors.lastname: Bürgisser
authors.affiliation: Division of Trauma Surgery, University Hospital Zurich, ZKF, Sternwartstrasse 14, CH-8091 Zurich, Switzerland.
authors.forename: Guido A
authors.initials: GA
authors.lastname: Wanner
authors.affiliation: Division of Trauma Surgery, University Hospital Zurich, ZKF, Sternwartstrasse 14, CH-8091 Zurich, Switzerland.
authors.forename: Paolo
authors.initials: P
authors.lastname: Cinelli
authors.affiliation: Division of Plastic and Hand Surgery, University Hospital Zurich, ZKF, Sternwartstrasse 14, CH-8091 Zurich, Switzerland. Electronic address: johanna.buschmann@usz.ch.
authors.forename: Johanna
authors.initials: J
authors.lastname: Buschmann
mesh_terms: D000273:Adipose Tissue / Q000166:cytology*; D001696:Biomechanical Phenomena; D040761:Biomimetic Materials; D002130:Calcium Phosphates / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D002478:Cells, Cultured; D018920:Coculture Techniques; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism; D050723:Fractures, Bone / Q000473:pathology*; D005599:Fractures, Ununited / Q000473:pathology*; D006801:Humans; D053761:Nanocomposites; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism; D010012:Osteogenesis; D013234:Stem Cells; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds
chemical_list: D002130:Calcium Phosphates; C519480:amorphous calcium phosphate
keywords: Adipose-derived stem cell; Amorphous calcium phosphate; Bone; Co-culture; Composite; Nanoparticle; PLGA