An approachable human adult stem cell source for hard‐tissue engineering

TLDR

Human deciduous dental pulp stem cells were isolated from children aged 6–10, sorted for c‑kit⁺/CD34⁺/STRO‑1⁺, and cultured with 20 % FBS to induce osteogenic, adipogenic (dexamethasone), or myogenic (co‑culture with C2C12) differentiation. The differentiated cells expressed osteogenic markers (CD44, osteocalcin, RUNX‑2), secreted mineralized matrix, formed 3‑D woven bone that stained strongly for ALP, alizarin red, and calcein, and, when transplanted into immunosuppressed rats, remodeled into lamellar bone containing osteocytes. © 2005 Wiley‑Liss, Inc.

Abstract

Abstract Stem cells were obtained from deciduous dental pulp of healthy subjects, aged 6–10 years. This stem cell population was cultured, expanded, and specifically selected, detecting using a FACsorter, c‐kit, CD34, and STRO‐1 antigen expression. Then, c‐kit + /CD34 + /STRO‐1 + cells were replaced in the culture medium added of 20% FBS, leading to osteoblast differentiation. In fact, these cells, after a week, showed a large positivity for CD44, osteocalcin, and RUNX‐2 markers. To achieve an adipocytic differentiation, cells, after sorting, were challenged with dexamethason 10 −8 mM in the same culture medium. To obtain myotube fusion, sorted cells were co‐cultured in ATCC medium with mouse myogenic C2C12 cells and, after a week, human stem cell nuclei were found to be able to fuse, forming myotubes. Differentiated osteoblasts, as assessed by a large positivity to several specific antibodies, after 30 days of culture and already in vitro, started to secrete an extracellular mineralized matrix, which, 2 weeks later, built a considerable number of 3D woven bone samples, which showed a strong positivity to alkaline phosphatase (ALP), alizarin red, calcein, other than to specific antibodies. These bone samples, after in vivo transplantation into immunosuppressed rats, were remodeled in a lamellar bone containing entrapped osteocytes. Therefore, this study provides strong evidence that human deciduous dental pulp is an approachable “niche” of stromal stem cells, and that it is an ideal source of osteoblasts, as well as of mineralized tissue, ready for bone regeneration, transplantation, and tissue‐based clinical therapies. © 2005 Wiley‐Liss, Inc.