Odontoblast Differentiation of Human Dental Pulp Cells in Explant Cultures

Abstract

In order to elucidate the mechanisms involved in human dentin formation, we developed a cell culture system to promote differentiation of dental pulp cells into odontoblasts. Explants from human teeth were cultured in Eagle's basal medium supplemented with 10% or 15% fetal calf serum, with or without beta-glycerophosphate (beta GP). Addition of beta GP to the culture medium induced odontoblast features in the cultured pulp cells. Cells polarized and some of them exhibited a typical cellular extension. In some cases, cells aligned with their processes oriented in the same direction and developed junctional complexes similar to the terminal web linking odontoblasts in vivo. Fine structural analyses showed the presence of typical intracellular organelles of the odontoblast body, whereas the process contained only cytoskeleton elements and secretory vesicles. Polarized cells deposited onto the plastic dishes an abundant and organized type I collagen-rich matrix with areas of mineralization appearing thereafter. X-ray microanalysis showed the presence of calcium and phosphorus and the electron diffraction pattern confirmed the apatitic crystal structure of the mineral. High expression of alpha 1 (1) collagen mRNAs was detected in all polarized cells whereas dentin sialoprotein gene was mainly expressed in mineralizing areas. This cell culture system allowed for the differentiation of pulp cells into odontoblasts, at both the morphological and functional level. Moreover, these cells presented a spatial organization similar to the odontoblastic layer.

Postnatal human dental pulp stem cells (DPSCs) in vitro and in vivo

“…Previous studies have looked at the odontogenic potential of adult human dental pulp by using a number of organ, explant, and cell-culture methods and noted the ability of such cultures to mineralize, at least in part (4,19,20,31). Our data also demonstrates the potential of DPSCs to form calcified deposits in vitro, as do BMSCs (5,6,32).…”

Lipoteichoic Acid Increases TLR and Functional Chemokine Expression while Reducing Dentin Formation in In Vitro Differentiated Human Odontoblasts

“…To study the expression of TLRs by odontoblasts, we used a pure population of cells generated in vitro that are similar in many aspects to in vivo odontoblasts (14,16). We observed the constitutive expression of TLR1-6 and 9 genes but not TLR7, 8, and 10 genes.…”

“…In the present study, we used odontoblasts generated in vitro from cultures of human dental pulp explants (14). In these conditions, dental pulp cells give rise to highly differentiated cells that exhibit many odontoblast features such as cell body polarization, formation of a typical process at the cell pole opposite to the nucleus, and strong expression of specific markers, including type I collagen, dentin sialophosphoprotein (DSPP), TGF-␤1, phosphate regulating gene with homologies to endopeptidases on the X chromosome, osteoadherin, and reelin (14,15,16,17).…”

Isolation, Characterization and Comparative Differentiation of Human Dental Pulp Stem Cells Derived from Permanent Teeth by Using Two Different Methods

“…19,20 Easy obtained potential with minimum pain & morbidity make human DPSCs as a valuable source of MSCs compared to the ordinary sources, such as bone marrow mesenchymal stem cells 21 . In general, DPSCs have been isolated by either outgrowth method, i.e., migration of stem cells from pulp tissue explants (DPSC-OG) [22][23][24] , and/or by enzymatic digestion (DPSC-ED) 4,6,25 . Previous studies have shown that the isolation method and culture conditions can induce different populations or lineages under in vitro passages 26,27 .…”