The aim of this study was to evaluate the level of odontogenic differentiation of dental pulp stem cells (DPSCs) on hydrogel scaffolds derived from bone extracellular matrix (bECM) in comparison to those seeded on collagen I (Col-I), one of the main components of dental pulp ECM. DPSCs isolated from human third molars were characterized for surface marker expression and odontogenic potential prior to seeding into bECM or Col-I hydrogel scaffolds. The cells were then seeded onto bECM and Col-I hydrogel scaffolds and cultured under basal conditions or with odontogenic and growth factor (GF) supplements. DPSCs cultivated on tissue culture polystyrene (TCPS) with and without supplements were used as controls. Gene expression of dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP-1) and matrix extracellular phosphoglycoprotein (MEPE) was evaluated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and mineral deposition was observed by Von Kossa staining. When DPSCs were cultured on bECM hydrogels, the mRNA expression levels of DSPP, DMP-1 and MEPE genes were significantly upregulated with respect to those cultured on Col-I scaffolds or TCPS in the absence of extra odontogenic inducers. In addition, more mineral deposition was observed on bECM hydrogel scaffolds as demonstrated by Von Kossa staining. Moreover, DSPP, DMP-1 and MEPE mRNA expressions of DPSCs cultured on bECM hydrogels were further upregulated by the addition of GFs or osteo/odontogenic medium compared to Col-I treated cells in the same culture conditions. These results demonstrate the potential of the bECM hydrogel scaffolds to stimulate odontogenic differentiation of DPSCs.

Dental pulp is known to be an accessible and important source of multipotent mesenchymal progenitor cells termed dental pulp stem cells (DPSCs). DPSCs can differentiate into odontoblast-like cells and maintain pulp homeostasis by the formation of new dentin which protects the underlying pulp. DPSCs similar to other mesenchymal stem cells (MSCs) reside in a niche, a complex microenvironment consisting of an extracellular matrix, other local cell types and biochemical stimuli that influence the decision between stem cell (SC) self-renewal and differentiation. In addition to biochemical factors, mechanical factors are increasingly recognized as key regulators in DPSC behavior and function. Thus, microenvironments can significantly influence the role and differentiation of DPSCs through a combination of factors which are biochemical, biomechanical and biophysical in nature. Under in vitro conditions, it has been shown that DPSCs are sensitive to different types of force, such as uniaxial mechanical stretch, cyclic tensile strain, pulsating fluid flow, low-intensity pulsed ultrasound as well as being responsive to biomechanical cues presented in the form of micro- and nano-scale surface topographies. To understand how DPSCs sense and respond to the mechanics of their microenvironments, it is essential to determine how these cells convert mechanical and physical stimuli into function, including lineage specification. This review therefore covers some aspects of DPSC mechanoresponsivity with an emphasis on the factors that influence their behavior. An in-depth understanding of the physical environment that influence DPSC fate is necessary to improve the outcome of their therapeutic application for tissue regeneration.

We provide a detailed description of mesenchymal stem cells (MSCs) isolated from human periapical cysts, which we have termed hPCy-MSCs. These cells have a fibroblast-like shape and adhere to tissue culture plastic surfaces. hPCy-MSCs possess high proliferative potential and self-renewal capacity properties. We characterised the immunophenotype of hPCy-MSCs (CD73⁺, CD90⁺, CD105⁺, CD13⁺, CD29⁺, CD44⁺, CD45^-, STRO-1⁺, CD146⁺) by flow cytometry and immunofluorescence. hPCy-MSCs possess the potential to differentiate into osteoblast- and adipocyte-like cells in vitro. Multi-potentiality was evaluated with culture-specific staining and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis for osteo/odontogenic and adipogenic markers. This is the first report to indicate that human periapical cysts contain cells with MSC-like properties. Taken together, our findings indicate that human periapical cysts could be a rich source of MSCs.

Regenerative medicine is an emerging field of biotechnology that combines various aspects of medicine, cell and molecular biology, materials science and bioengineering in order to regenerate, repair or replace tissues.

Dental pulp tissue represents a source of mesenchymal stem cells that have a strong differentiation potential towards the osteogenic lineage. The objective of the current study was to examine in vitro osteogenic induction of dental pulp stem cells (DPSCs) cultured on hydrogel scaffolds derived from decellularized bone extracellular matrix (bECM) compared to collagen type I (Col-I), the major component of bone matrix. DPSCs in combination with bECM hydrogels were cultured under three different conditions: basal medium, osteogenic medium and medium supplemented with growth factors (GFs) and cell growth, mineral deposition, gene and protein expression were investigated. The DPSCs/bECM hydrogel constructs cultured in basal medium showed that cells were viable after three weeks and that the expression of runt-related transcription factor 2 (RUNX-2) and bone sialoprotein (BSP) were significantly upregulated in the absence of extra osteogenic inducers compared to Col-I hydrogel scaffolds. In addition, the protein expression levels of BSP and osteocalcin were higher on bECM with respect to Col-I hydrogel scaffolds. Furthermore, DPSCs/bECM hydrogels cultured with osteogenic or GFs supplemented medium displayed a higher upregulation of the osteo-specific markers compared to Col-I hydrogels in identical media. Collectively, our results demonstrate that bECM hydrogels might be considered as suitable scaffolds to support osteogenic differentiation of DPSCs.

Bone regeneration in craniomaxillofacial surgery represents an issue that involves both surgical and aesthetic aspects. The most recent studies on bone tissue engineering involving adipose-derived stromal/stem cells (ASCs) have clearly demonstrated that such cells can play a crucial role in the treatment of craniomaxillofacial defects, given their strong commitment towards the osteogenic phenotype. A deeper knowledge of the molecular mechanisms underlying ASCs is crucial for a correct understanding of the potentialities of ASCs-based therapies in the most complex maxillofacial applications. In this topical review, we analyzed the molecular mechanisms of ASCs related to their support toward angiogenesis and osteogenesis, during bone regeneration. Moreover, we analyzed both case reports and clinical trials reporting the most promising clinical applications of ASCs in the treatment of craniomaxillofacial defects. Our study aimed to report the main molecular and clinical features shown by ASCs, used as a therapeutic support in bone engineering, as compared to the use of conventional autologous and allogeneic bone grafts.