title: Pulp cell tracking by radionuclide imaging for dental tissue engineering.
abstract: Pulp engineering with dental mesenchymal stem cells is a promising therapy for injured teeth. An important point is to determine the fate of implanted cells in the pulp over time and particularly during the early phase following implantation. Indeed, the potential engraftment of the implanted cells in other organs has to be assessed, in particular, to evaluate the risk of inducing ectopic mineralization. In this study, our aim was to follow by nuclear imaging the radiolabeled pulp cells after implantation in the rat emptied pulp chamber. For that purpose, indium-111-oxine (¹¹¹In-oxine)-labeled rat pulp cells were added to polymerizing type I collagen hydrogel to obtain a pulp equivalent. This scaffold was implanted in the emptied pulp chamber space in the upper first rat molar. Labeled cells were then tracked during 3 weeks by helical single-photon emission computed tomography (SPECT)/computed tomography performed on a dual modality dedicated small animal camera. Negative controls were performed using lysed radiolabeled cells obtained in a hypotonic solution. In vitro data indicated that ¹¹¹In-oxine labeling did not affect cell viability and proliferation. In vivo experiments allowed a noninvasive longitudinal follow-up of implanted living cells for at least 3 weeks and indicated that SPECT signal intensity was related to implanted cell integrity. Notably, there was no detectable systemic release of implanted cells from the tooth. In addition, histological analysis of the samples showed mitotically active fibroblastic cells as well as neoangiogenesis and nervous fibers in pulp equivalents seeded with entire cells, whereas pulp equivalents prepared from lysed cells were devoid of cell colonization. In conclusion, our study demonstrates that efficient labeling of pulp cells can be achieved and, for the first time, that these cells can be followed up after implantation in the tooth by nuclear imaging. Furthermore, it appears that grafted cells retained the label and are viable to follow the repair process. This technique is expected to be of major interest for monitoring implanted cells in innovative therapies for injured teeth.
authors.affiliation: 1 EA2496, Dental School, University Paris Descartes PRES Sorbonne Paris Cité , Montrouge, France .
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Souron
authors.forename: Anne
authors.initials: A
authors.lastname: Petiet
authors.forename: Franck
authors.initials: F
authors.lastname: Decup
authors.forename: Xuan Vinh
authors.initials: XV
authors.lastname: Tran
authors.forename: Julie
authors.initials: J
authors.lastname: Lesieur
authors.forename: Anne
authors.initials: A
authors.lastname: Poliard
authors.forename: Dominique
authors.initials: D
authors.lastname: Le Guludec
authors.forename: Didier
authors.initials: D
authors.lastname: Letourneur
authors.forename: Catherine
authors.initials: C
authors.lastname: Chaussain
authors.forename: Francois
authors.initials: F
authors.lastname: Rouzet
authors.forename: Sibylle
authors.initials: S
authors.lastname: Opsahl Vital
mesh_terms: D000818:Animals; D002470:Cell Survival; D058948:Cell Tracking / Q000379:methods*; D003782:Dental Pulp / Q000166:cytology* / Q000000981:diagnostic imaging*; D023421:Models, Animal; D009942:Organometallic Compounds; D015125:Oxyquinoline / Q000031:analogs & derivatives; D011672:Pulpotomy; D051381:Rats; D011917:Rats, Inbred Lew; D023822:Tissue Engineering / Q000379:methods*; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D051598:Whole Body Imaging; D014945:Wound Healing
chemical_list: D009942:Organometallic Compounds; C032950:indium oxine; D015125:Oxyquinoline