title: Scaffold-free Prevascularized Microtissue Spheroids for Pulp Regeneration.
abstract: Creating an optimal microenvironment that mimics the extracellular matrix (ECM) of natural pulp and securing an adequate blood supply for the survival of cell transplants are major hurdles that need to be overcome in dental pulp regeneration. However, many currently available scaffolds fail to mimic essential functions of natural ECM. The present study investigated a novel approach involving the use of scaffold-free microtissue spheroids of dental pulp stem cells (DPSCs) prevascularized by human umbilical vein endothelial cells (HUVECs) in pulp regeneration. In vitro-fabricated microtissue spheroids were inserted into the canal space of tooth-root slices and were implanted subcutaneously into immunodeficient mice. Histological examination revealed that, after four-week implantation, tooth-root slices containing microtissue spheroids resulted in well-vascularized and cellular pulp-like tissues, compared with empty tooth-root slices, which were filled with only subcutaneous fat tissue. Immunohistochemical staining indicated that the tissue found in the tooth-root slices was of human origin, as characterized by the expression of human mitochondria, and contained odontoblast-like cells organized along the dentin, as assessed by immunostaining for nestin and dentin sialoprotein (DSP). Vascular structures formed by HUVECs in vitro were successfully anastomosed with the host vasculature upon transplantation in vivo, as shown by immunostaining for human CD31. Collectively, these findings demonstrate that prevascularized, scaffold-free, microtissue spheroids can successfully regenerate vascular dental pulp-like tissue and also highlight the significance of the microtissue microenvironment as an optimal environment for successful pulp-regeneration strategies.
authors.affiliation: Endodontics, Comprehensive Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: W L
authors.initials: WL
authors.lastname: Dissanayaka
authors.affiliation: Endodontics, Comprehensive Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: L
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Hargreaves
authors.affiliation: Periodontology and Public Health, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: L
authors.initials: L
authors.lastname: Jin
authors.affiliation: Endodontics, Comprehensive Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China zhangcf@hku.hk.
authors.forename: C
authors.initials: C
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D018929:Cell Culture Techniques; D060833:Cellular Microenvironment / Q000502:physiology; D018920:Coculture Techniques; D003782:Dental Pulp / Q000166:cytology* / Q000502:physiology; D003786:Dental Pulp Cavity / Q000166:cytology; D003804:Dentin / Q000166:cytology; D016326:Extracellular Matrix Proteins; D061307:Human Umbilical Vein Endothelial Cells / Q000502:physiology; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D055806:Microvessels / Q000166:cytology; D008928:Mitochondria / Q000648:ultrastructure; D023421:Models, Animal; D018919:Neovascularization, Physiologic / Q000502:physiology; D064231:Nestin / Q000032:analysis; D009804:Odontoblasts / Q000166:cytology; D010750:Phosphoproteins; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis; D012038:Regeneration / Q000502:physiology*; D012795:Sialoglycoproteins; D018874:Spheroids, Cellular / Q000502:physiology*; D033581:Stem Cell Transplantation / Q000379:methods; D013234:Stem Cells / Q000502:physiology*; D023822:Tissue Engineering / Q000379:methods*; D055815:Young Adult; D000099311:Dentin Sialophosphoprotein
chemical_list: D016326:Extracellular Matrix Proteins; D064231:Nestin; D010750:Phosphoproteins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein; C577484:NES protein, human
keywords: angiogenesis; endodontics; extracellular matrix; regenerative medicine; stem cells; tissue engineering