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

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.

Human postnatal dental pulp cells co-differentiate into osteoblasts and endotheliocytes: a pivotal synergy leading to adult bone tissue formation

“…The formation of vessels explains the vitality of bone chips when transplanted in immunosuppressed rats. 5,6 Figure 3 flk-1 þ exerts a pivotal role in coupling osteoblast and endotheliocyte differentiation, as previously hypothesized [21][22][23] and the intimate relationship and interplay between endotheliocytes and osteoblasts is the key to obtain complete differentiation and formation of mature bone.…”

“…Differentiated cells were obtained from sorted stem cells cultured for at least 30 days in a-MEM culture medium with 20% FBS (all purchased from Invitrogen, San Giuliano Milanese, Milan, Italy); in fact, FBS exerts a differentiation activity favoring osteoblastic differentiation when used in high percentage. 5,6 FAC analysis and sortings. Cells were detached using 0.02%.…”

“…Recently, we showed that some of these stromal DPSCs (SBP-DPSCs) 5 and stromal SHEDs (SBP-SHEDs) 6 differentiate into various cells and tissues under particular conditions. Cytotypes include neural progenitors, adipocytes, myotubes and pre-osteoblasts; the latter are then able to produce three-dimensional bone tissue chips in vitro that, after in vivo transplantation in immunosuppressed rats, are quickly remodelled into a lamellar bone.…”

“…Owing to their high proliferation rate and efficiency in producing bone chips, DPSCs 5,6 seem to be better candidates for the study of bone formation than bone marrow stem cells (BMSCs), 7 whose efficiency is limited by the fact that they differentiate into osteoblasts and produce small calcified nodules and not chips of bone tissue. Moreover, complete differentiation with subsequent tissue formation, including an adequate blood supply, is of paramount importance for tissue repair and transplantation.…”

Putative mesenchymal stem cells isolated from adult human ovaries

“…From developmental perspective it is believed, that MSCs originate from mesodermal germ layer. They have been isolated from many tissues, such as adipose tissue [1], bone marrow [2], skeletal muscle [3], deciduous dental pulp [4], synovium [5], Wharton's jelly [6], umbilical cord [7] and umbilical cord blood [8]. Regardless of the source, these cells should meet the requirements recommended by the International Society for Cellular Therapy [9].…”