Harnessing the differentiation of stem cells into bone-forming cells represents an intriguing avenue for the creation of functional skeletal tissues. Therefore, a profound understanding of bone development and morphogenesis sheds light on the regenerative application of stem cells in orthopedics and dentistry. In this concise review, we summarize the studies deciphering the mechanisms that govern osteoblast differentiation in the context of in vitro formation of bone-like nodules, including morphologic and molecular events as well as cellular contributions to mineral nucleation, occurring during osteogenic differentiation of stem cells. This article also highlights the limitations of current translational applications of stem cells and opportunities to use the bone-like nodule model for bone regenerative therapies. STEM CELLS TRANSLATIONAL MEDICINE 2016;5:1587-1593 SIGNIFICANCEHarnessing the differentiation of stem cells into bone-forming cells represents an intriguing avenue for the creation of functional skeletal tissues. Therefore, a profound understanding of bone development and morphogenesis sheds light on the regenerative application of stem cells in orthopedics and dentistry. In this concise review, studies deciphering the mechanisms that govern osteoblast commitment and differentiation are summarized. This article highlights the limitations of current translational applications of stem cells and the opportunities to use the bone-like nodule model for bone regenerative therapies.

BACKGROUND: To favor regeneration following critical bone defect, a combination of autologous bone graft and biomaterials is currently used. Major drawbacks of such techniques remain the availability of the autologous material and the second surgical site, inducing pain and morbidity. OBJECTIVE: Our aim was to investigate the biocompatibility in vitro of three dimensions hybrid biodegradable scaffolds combining osteoconductive properties of hydroxyapatite and anti-inflammatory properties of chitosan. METHODS: Hybrid scaffolds were characterized by microscopic observations, equilibrium swelling ratio and overtime weight loss measurements. In vitro studies were performed using primary human bone cells cultured for 7, 14 and 21 days. Cell viability, proliferation, morphology and differentiation through alkaline phosphatase (ALP) activity measurement were assessed. RESULTS: Characterization of our scaffolds demonstrated porous, hydrophilic and biodegradable characteristics. In vitro studies showed that these scaffolds have induced slight decrease in cell death and proliferation comparing to the culture plastic substrate control condition, as well as increased short term osteoinductive properties. CONCLUSIONS: In this study, we have provided evidence that our hybrid hydroxyapatite/chitosan scaffolds could be suitable for bone filling.

Designing materials to direct stem cell fate has a relevant impact on stem cell biology and provides insights facilitating their clinical application in regenerative medicine. Inspired by natural bone compositions, a friendly automated spray-assisted system was used to build calcium phosphate substrate (CaP). Sprayed biomimetic solutions using mild conditions led to the formation of CaP with controlled physical properties, good bioactivity and biocompatibility. Herein, we show that via optimization of physical properties, CaP substrate induce osteogenic differentiation of Wharton's jelly stem cells (WJ-SCs) without adding osteogenic supplement factors. These results suggest a great potential of sprayed CaP and WJ-SCs in bone tissue engineering and may facilitate the transition from bench to beside and the development of clinically successful engineered bone.

No abstract

No abstract