title: Evaluation of the donor cell contribution in rhBMP-2 mediated bone formation with chitosan thermogels using fluorescent protein reporter mice.
abstract: Our current understanding regarding the contribution of donor cells in growth factor and cell based tissue regeneration strategies is limited. The present study attempts to utilize fluorescent protein reporter mice [Col3.6Topaz (enhanced yellow fluorescent protein, EYFP) as host and Col3.6Cyan (enhanced cyan fluorescent protein, ECFP) as donor] to determine donor cell contribution in bone regeneration using a bilateral calvarial defect model. Thermogelling chitosan hydrogels (Chi-AHP) were used as bone marrow stromal cell (BMSC) delivery vehicle in the presence and absence of recombinant human bone morphogenetic protein-2 (rhBMP-2). Co-delivery of rhBMP-2 and donor BMSCs led to a significant increase in bone formation indicating the potential of using the combination approach for improved regeneration. On a cellular level, presence of rhBMP-2 resulted in an increased host cell derived osteoblast infiltration at 8 weeks. However, the new mineralized tissue presented two distinct morphological features based on its cellular origin. Regenerated tissue associated with ECFP positive donor cells showed a woven bone-like structure with diffuse alizarin complexone (AC) label and minimal tartrate resistant acid phosphatase (TRAP) activity, indicating the presence of immature early osteoblast cells depositing mineralized tissue without progressing to a mature lamellar bone. Host derived bone showed sharp mineralization line (AC), strong alkaline phosphatase (ALP) and TRAP activity, indicating the presence of actively mineralizing and remodeling, mature lamellar bone matrix. The study demonstrated the remarkable potential of transgenic reporters to improve our understanding of donor cell contribution during bone formation.
authors.affiliation: Department of Orthopaedic Surgery, UConn Health, Farmington, Connecticut, 06030.|Institute for Regenerative Engineering, The Raymond Beverly Sackler Center for Biomedical, Biological, Physical and Engineering Sciences, UConn Health, Farmington, Connecticut, 06030.
authors.forename: Shalini V
authors.initials: SV
authors.lastname: Gohil
authors.affiliation: Connecticut Institute for Clinical and Translational Science, Institute for Systems Genomics, University of Connecticut, Farmington, Connecticut, 06030.
authors.forename: Chia-Ling
authors.initials: CL
authors.lastname: Kuo
authors.affiliation: Department of Orthopaedic Surgery, UConn Health, Farmington, Connecticut, 06030.
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Adams
authors.affiliation: Center for Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, School of Dental Medicine, UConn Health, Farmington, Connecticut, 06030.
authors.forename: Peter
authors.initials: P
authors.lastname: Maye
authors.affiliation: Center for Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, School of Dental Medicine, UConn Health, Farmington, Connecticut, 06030.
authors.forename: David W
authors.initials: DW
authors.lastname: Rowe
authors.affiliation: Department of Orthopaedic Surgery, UConn Health, Farmington, Connecticut, 06030.|Institute for Regenerative Engineering, The Raymond Beverly Sackler Center for Biomedical, Biological, Physical and Engineering Sciences, UConn Health, Farmington, Connecticut, 06030.|Departments of Material Science and Engineering, Biomedical Engineering and Institute of Material Science, University of Connecticut, Storrs, Connecticut, 06269.
authors.forename: Lakshmi S
authors.initials: LS
authors.lastname: Nair
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage* / Q000494:pharmacology; D001861:Bone Regeneration / Q000187:drug effects; D048271:Chitosan / Q000737:chemistry*; D016503:Drug Delivery Systems; D049452:Green Fluorescent Proteins / Q000032:analysis; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology; D051379:Mice; D008822:Mice, Transgenic; D010012:Osteogenesis / Q000187:drug effects*; D051381:Rats; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000494:pharmacology; D012886:Skull / Q000293:injuries* / Q000502:physiology; D054457:Tissue Scaffolds / Q000737:chemistry*; D016212:Transforming Growth Factor beta / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D055396:Bone Morphogenetic Protein 2; D020100:Hydrogels; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C527701:enhanced cyan fluorescent protein; C499469:recombinant human bone morphogenetic protein-2; D049452:Green Fluorescent Proteins; D048271:Chitosan
keywords: bone morphogenetic protein; chitosan; donor cell contribution; stem cells; transgenic fluorescent protein reporter mouse