title: Short-time survival and engraftment of bone marrow stromal cells in an ectopic model of bone regeneration.
abstract: In tissue-engineered applications bone marrow stromal cells (BMSCs) are combined with scaffolds to target bone regeneration; animal models have been devised and the cells' long-term engraftment has been widely studied. However, in regenerated bone, the cell number is severely reduced with respect to the initially seeded BMSCs. This reflects the natural low cellularity of bone but underlines the selectivity of the differentiation processes. In this respect, we evaluated the short-term survival of BMSCs, transduced with the luciferase gene, after implantation of cell-seeded scaffolds in a nude mouse model. Cell proliferation/survival was assessed by bioluminescence imaging: light production was decreased by 30% on the first day, reaching a 50% loss within 48 h. Less than 5% of the initial signal remained after 2 months in vivo. Apoptotic BMSCs were detected within the first 2 days of implantation. Interestingly, the initial frequency of clonogenic progenitors matched the percentage of in vivo surviving cells. Cytokines and inflammation may contribute to the apoptotic onset at the implant milieu. However, preculturing cells with tumor necrosis factor alpha enhanced survival, allowing detection of 8.1% of the seeded BMSCs 2 months after implantation. Thus culturing conditions may reduce the apoptotic overload of seeded osteoprogenitors, strengthening the constructs' osteogenic potential.
authors.affiliation: Stem Cell Laboratory, Advanced Biotechnology Center, Genova, Italy. paolo.giannoni@cba-biotecnologie.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Giannoni
authors.forename: Silvia
authors.initials: S
authors.lastname: Scaglione
authors.forename: Antonio
authors.initials: A
authors.lastname: Daga
authors.forename: Cristina
authors.initials: C
authors.lastname: Ilengo
authors.forename: Michele
authors.initials: M
authors.lastname: Cilli
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Quarto
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001672:Biocompatible Materials / Q000494:pharmacology; D001854:Bone Marrow Cells / Q000166:cytology* / Q000187:drug effects; D001861:Bone Regeneration / Q000187:drug effects / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000494:pharmacology; D017886:Durapatite / Q000494:pharmacology; D021621:Imaging, Three-Dimensional; D020007:Implants, Experimental; D008027:Light; D008163:Luminescent Measurements; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects; D051379:Mice; D008819:Mice, Nude; D008954:Models, Biological; D012756:Sheep; D017154:Stromal Cells / Q000166:cytology / Q000187:drug effects; D013997:Time Factors; D054457:Tissue Scaffolds / Q000737:chemistry; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D001672:Biocompatible Materials; D014409:Tumor Necrosis Factor-alpha; D003094:Collagen; D017886:Durapatite