The mesenchymal stem cells (MSCs) that reside in dental tissues hold a great potential for future applications in regenerative dentistry. In this study, we used human dental pulp cells, isolated from the molars (DPCs), in order to establish the organoid culture. DPCs were established after growing pulp cells in an MSC expansion media (MSC-EM). DPCs were subjected to organoid growth media (OGM) in comparison with human dental pulp stem cells (DPSCs). Inside the extracellular matrix in the OGM, the DPCs and DPSCs readily formed vessel-like structures, which were not observed in the MSC-EM. Immunocytochemistry analysis and flow cytometry analysis showed the elevated expression of CD31 in the DPCs and DPSCs cultured in the OGM. These results suggest endothelial cell-prone differentiation of the DPCs and DPSCs in organoid culture condition.

Introduction
 Materials and Methods
  Cell culture
  Isolation and culture of dental pulp stem cells
  Organoid culture of DPCs or DPSCs
  Flow cytometry analysis
  Tube formation assay
  Immunofluorescence staining
  Statistical analysis
 Results
  Human dental pulp stem cells in organoid culture
  Tube formation during organoid culture
  Tube formation assay with organoid culture-derived cells
  CD31 expression in organoid culture-derived cells
 Discussion
 References

• Eun Jin Seo(Department of Oral Biochemistry and Molecular Biology, Pusan National University School of Dentistry, Research Institute of Translational Dental Sciences, Pusan National University)
• Jae Kyung Park(Department of Oral Biochemistry and Molecular Biology, Pusan National University School of Dentistry, Research Institute of Translational Dental Sciences, Pusan National University)
• Hoim Jeong(Department of Oral Biochemistry and Molecular Biology, Pusan National University School of Dentistry, Research Institute of Translational Dental Sciences, Pusan National University)
• Jung Sook Kang(Department of Oral Biochemistry and Molecular Biology, Pusan National University School of Dentistry)
• Hyung-Ryong Kim(DGIST)
• Il Ho Jang(Department of Oral Biochemistry and Molecular Biology, Pusan National University School of Dentistry, Research Institute of Translational Dental Sciences, Pusan National University) Correspondence to