title: Humanized culture of periosteal progenitors in allogeneic serum enhances osteogenic differentiation and in vivo bone formation.
abstract: The translation of stem cell-based regenerative solutions from the laboratory to the clinic is often hindered by the culture conditions used to expand cell populations. Although fetal bovine serum (FBS) is widely used, regulatory bodies and safety concerns encourage alternative, xeno-free culturing practices. In an attempt to apply this approach to a bone-forming combination product of human periosteal progenitors (human periosteum derived cells) on a clinically used calcium phosphate carrier, FBS was substituted for human allogeneic serum (hAS) during cell expansion. It was found that cell proliferation was increased in hAS along with an apparent commitment to the osteogenic lineage, indicated by enhanced Runx2 expression, as well as alkaline phosphatase activity and matrix mineralization. Following analysis of signaling pathways, it was found that interferon-mediated signaling was downregulated, whereas JAK-STAT signaling was upregulated. STAT3 phosphorylation was enhanced in hAS-cultured human periosteum derived cells, inhibition of which ablated the proliferative effect of hAS. Furthermore, following in vivo implantation of hAS-cultured cells on NuOss scaffolds, enhanced bone formation was observed compared with FBS (71% increase, p < .001). Interestingly, the de novo-formed bone appeared to have a higher ratio of immature regions to mature regions, indicating that after 8 weeks implantation, tissue-formation processes were continuing. Integration of the implant with the environment appeared to be altered, with a decrease in calcium phosphate grain size and surface area, indicative of accelerated resorption. This study highlights the advantages of using humanized culture conditions for the expansion of human periosteal progenitors intended for bone regeneration.
authors.affiliation: Laboratory for Developmental and Stem Cell Biology, Skeletal Biology and Engineering Research Center, Prometheus, Division of Skeletal Tissue Engineering, and Department and Laboratory of Intensive Care Medicine, KU Leuven, Leuven, Belgium; Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery & Interventional Science, University College London, The Royal National Orthopaedic Hospital, Stanmore, Middlesex, United Kingdom.
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Roberts
authors.forename: Helen C
authors.initials: HC
authors.lastname: Owen
authors.forename: Wai Long
authors.initials: WL
authors.lastname: Tam
authors.forename: Lien
authors.initials: L
authors.lastname: Solie
authors.forename: Sophie J
authors.initials: SJ
authors.lastname: Van Cromphaut
authors.forename: Greet
authors.initials: G
authors.lastname: Van den Berghe
authors.forename: Frank P
authors.initials: FP
authors.lastname: Luyten
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000494:pharmacology*; D001842:Bone and Bones / Q000166:cytology*; D002130:Calcium Phosphates / Q000494:pharmacology; D002417:Cattle; D018929:Cell Culture Techniques / Q000379:methods; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects; D003470:Culture Media / Q000494:pharmacology; D064368:Healthy Volunteers; D006801:Humans; D010011:Osteocytes / Q000166:cytology*; D010521:Periosteum / Q000166:cytology*; D050796:STAT3 Transcription Factor / Q000037:antagonists & inhibitors; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D001798:Blood Proteins; D002130:Calcium Phosphates; D003470:Culture Media; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C020243:calcium phosphate
keywords: Adult stem cells; Bone; Culture; Differentiation; Mesenchymal stem cells; Osteoblast; Tissue regeneration