Souron Jean-Baptiste, Petiet Anne, Decup Franck, Tran Xuan Vinh, Lesieur Julie, Poliard Anne, Le Guludec Dominique, Letourneur Didier, Chaussain Catherine, Rouzet Francois, Opsahl Vital Sibylle
1 EA2496, Dental School, University Paris Descartes PRES Sorbonne Paris Cité , Montrouge, France .
Tissue Eng Part C Methods. 2014 Mar;20(3):188-97. doi: 10.1089/ten.TEC.2013.0148. Epub 2013 Aug 16.
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.
利用牙间充质干细胞进行牙髓工程是治疗受损牙齿的一种有前景的疗法。一个重要的问题是确定植入牙髓中的细胞随时间推移的命运，特别是在植入后的早期阶段。实际上，必须评估植入细胞在其他器官中的潜在植入情况，尤其是要评估诱发异位矿化的风险。在本研究中，我们的目的是通过核成像追踪放射性标记的牙髓细胞在大鼠空牙髓腔植入后的情况。为此，将铟 - 111 - 奥辛（¹¹¹In - 奥辛）标记的大鼠牙髓细胞添加到聚合的I型胶原水凝胶中以获得牙髓等效物。将该支架植入大鼠上颌第一磨牙的空牙髓腔空间。然后通过在双模态专用小动物相机上进行的螺旋单光子发射计算机断层扫描（SPECT）/计算机断层扫描，在3周内追踪标记细胞。使用在低渗溶液中获得的裂解放射性标记细胞进行阴性对照。体外数据表明¹¹¹In - 奥辛标记不影响细胞活力和增殖。体内实验允许对植入的活细胞进行至少3周的无创纵向追踪，并表明SPECT信号强度与植入细胞的完整性相关。值得注意的是，没有检测到植入细胞从牙齿的全身释放。此外，对样本的组织学分析显示，在接种完整细胞的牙髓等效物中有有丝分裂活跃的成纤维细胞以及新生血管形成和神经纤维，而由裂解细胞制备的牙髓等效物则没有细胞定植。总之，我们的研究表明可以实现牙髓细胞的有效标记，并且首次表明这些细胞在植入牙齿后可以通过核成像进行追踪。此外，似乎移植的细胞保留了标记并且在追踪修复过程中是有活力的。预计该技术对于监测受损牙齿创新疗法中植入细胞将具有重要意义。
