Craniofacial Bone Tissue Engineering Research Articles

Bioactive glass-containing hydrogel delivery system for osteogenic differentiation of human dental pulp stem cells.

Osteoconductive hydrogels can be fabricated by incorporating necessary growth factors and bioactive particles or simply utilizing the ability of the hydrogel itself to induce bone regeneration. The osteogenic inductive potential of the bioactive glass microparticles (BG MPs) has been well-studied. However, the role of the hydrogel embedding the BG MPs on the osteogenic differentiation of the encapsulated stem cells has not been well established. Moreover, it has been reported that the dental pulp stem cell (DPSC) has the capability of regenerating the craniofacial bone tissue when receiving the necessary osteogenic signals from the microenvironment. In the current study, we have fabricated a composite hydrogel based on alginate and Matrigel containing BG MPs and evaluated the role of the BG MPs and Matrigel on osteogenic differentiation of the encapsulated DPSCs. Our results confirmed that presence of Matrigel enhances the osteogenic differentiation of the DPSCs regardless of the decrease in elasticity of the hydrogel in presence of the BG MPs. This strategy of modifying the microenvironment can be a promising approach for craniofacial bone tissue engineering.

Osteogenic potential of mesenchymal stem cells from rat mandible to regenerate critical sized calvarial defect

Although bone marrow–derived mesenchymal stem cells (MSCs) have been extensively explored in bone tissue engineering, only few studies using mesenchymal stem cells from mandible (M-MSCs) have been reported. However, mesenchymal stem cells from mandible have the potential to be as effective as femur-derived mesenchymal stem cells (F-MSCs) in regenerating bone, especially in the orofacial regions, which share embryonic origin, proximity, and accessibility. M-MSCs were isolated and characterized using mesenchymal stem cell–specific markers, colony forming assay, and multi-potential differentiation. In vitro osteogenic potential, including proliferation, osteogenic gene expression, alkaline phosphatase activity, and mineralization, was examined and compared. Furthermore, in vivo bone formations of F-MSCs and M-MSCs in rat critical sized defect were evaluated using microCT and histology. M-MSCs from rat could be successfully isolated and expanded while preserving their MSC’s characteristics. M-MSCs demonstrated a comparable proliferation and mineralization potentials and in vivo bone formation as F-MSCs. M-MSCs is a promising cell source candidate for craniofacial bone tissue engineering.

CVD-grown monolayer graphene induces osteogenic but not odontoblastic differentiation of dental pulp stem cells

ObjectiveThe objective was to investigate the potential of graphene (Gp) to induce odontogenic and osteogenic differentiation in dental pulp stem cells (DPSC). MethodsGp was produced by chemical vapor deposition. DPSC were seeded on Gp or glass (Gl). Cells were maintained in culture medium for 28 days. Every two days, culture medium from Gp was used to treat cells on Gl and vice versa. Mineralization and differentiation of DPSC on all substrates were evaluated after 14 and 28 days by alizarin red S staining, qPCR, immunofluorescence and FACS. Statistics were performed with two-way ANOVA and multiple comparisons were performed using Tukey's post hoc test at a pre-set significance level of 5%. ResultsAfter 14 and 28 days, Gp induced higher levels of mineralization as compared to Gl. Odontoblastic genes (MSX-1, PAX and DMP) were down-regulated and osteogenic genes and proteins (RUNX2, COL and OCN) were significantly upregulated on Gp comparing to Gl (p<0.05 for all cases). Medium from Gp induced downregulation of odontoblastic genes and increased bone-related gene and protein on Gl. SignificanceGraphene induced osteogenic and not odontoblastic differentiation of DPSC without the use of chemical inducers for osteogenesis. Graphene has the potential to be used as a substrate for craniofacial bone tissue engineering research.

Osteogenic Differentiation of Orofacial Tissue-Derived Mesenchymal Stem Cells- A Review

Background: Bone loss due to congenital or acquired abnormalities of the craniofacial skeleton is of common occurrence. Surgical repair and reconstruction of the critical size bony defects are clinically challenging. Of the several approaches, stem cell-based bone-regeneration is gaining momentum. Stem cells from the orofacial region have been identified as potential source for craniofacial bone reconstruction as they are derived from cranial neural crest cells. Isolation of orofacial stem cells is minimally invasive, and they are highly proliferative with the ability to differentiate into multiple lineages. Method: The current review gives a description on mesenchymal stem cells derived from the orofacial region (OMSCs) and updates the information on their use in bone regeneration. Results: Studies have reported that OMSCs are highly proliferative with the ability to differentiate into osteogenic lineage. Various factors influencing osteogenic potential of OMSCs have been discussed. Conclusion: The findings from the previous literature confirms the potential use of OMSCs in craniofacial bone tissue engineering. Keywords: Bone regeneration, craniofacial skeleton, critical size defect, mesenchymal stem cells, neural crest, orofacial stem cells.

Mesenchymal stem cells and alginate microcarriers for craniofacial bone tissue engineering: A review.

Craniofacial bone is a complex structure with an intricate anatomical and physiological architecture. The defects that exist in this region therefore require a precise control of osteogenesis in their reconstruction. Unlike traditional surgical intervention, tissue engineering techniques mediate bone development with limited postoperative risk and cost. Alginate stands as the premier polymer in bone repair because of its mild ionotropic gelation and excellent biocompatibility, biodegradability, and injectability. Alginate microcarriers are candidates of choice to mediate cells and accommodate into 3-D environment. Several studies reported the use of alginate microcarriers for delivering cells, drugs, and growth factors. This review will explore the potential use of alginate microcarrier for stem cell systems and its application in craniofacial bone tissue engineering.

Biodegradable, in Situ-Forming Cell-Laden Hydrogel Composites of Hydroxyapatite Nanoparticles for Bone Regeneration

Hydroxyapatite nanoparticles (HANPs) were suspended in injectable, biodegradable, phosphate-containing, dual-gelling macromer solutions that were used to encapsulate mesenchymal stem cells (MSCs) within stable hydrogel composites when elevated to physiologic temperature. The suspension of HANPs at 0.75%w/v within the hydrogels was found to have no significant effect on the swelling ratio or the compressive modulus. The MSCs were shown to survive the encapsulation process, and live cells were detected within the hydrogel composites for up to 28 days. The activity of osteogenic marker alkaline phosphatase increased with time in cell-laden hydrogel composites over the 28 days in osteogenic medium, suggesting that the joint combination of encapsulated MSCs within a HANP- and phosphate-containing hydrogel can enhance enzyme activity to assist in hydrogel mineralization. This is observed in the calcium biochemical assays, where the incorporation of HANPs significantly improved both cell-laden and acellular hydrogel composite mineralization over time. Hydrogel nanocomposites that form in situ while facilitating cell delivery and mineralization are promising materials for craniofacial bone tissue engineering.

Biodegradable, phosphate-containing, dual-gelling macromers for cellular delivery in bone tissue engineering

Injectable, biodegradable, dual-gelling macromer solutions were used to encapsulate mesenchymal stem cells (MSCs) within stable hydrogels when elevated to physiologic temperature. Pendant phosphate groups were incorporated in the N-isopropyl acrylamide-based macromers to improve biointegration and facilitate hydrogel degradation. The MSCs were shown to survive the encapsulation process, and live cells were detected within the hydrogels for up to 28 days in vitro. Cell-laden hydrogels were shown to undergo significant mineralization in osteogenic medium. Cell-laden and acellular hydrogels were implanted into a critical-size rat cranial defect for 4 and 12 weeks. Both cell-laden and acellular hydrogels were shown to degrade in vivo and help to facilitate bone growth into the defect. Improved bone bridging of the defect was seen with the incorporation of cells, as well as with higher phosphate content of the macromer. Furthermore, direct bone-to-hydrogel contact was observed in the majority of implants, which is not commonly seen in this model. The ability of these macromers to deliver stem cells while forming in situ and subsequently degrade while facilitating bone ingrowth into the defect makes this class of macromers a promising material for craniofacial bone tissue engineering.

Perinatal stem cells: A promising cell resource for tissue engineering of craniofacial bone.

In facing the mounting clinical challenge and suboptimal techniques of craniofacial bone defects resulting from various conditions, such as congenital malformations, osteomyelitis, trauma and tumor resection, the ongoing research of regenerative medicine using stem cells and concurrent advancement in biotechnology have shifted the focus from surgical reconstruction to a novel stem cell-based tissue engineering strategy for customized and functional craniofacial bone regeneration. Given the unique ontogenetical and cell biological properties of perinatal stem cells, emerging evidence has suggested these extraembryonic tissue-derived stem cells to be a promising cell source for extensive use in regenerative medicine and tissue engineering. In this review, we summarize the current achievements and obstacles in stem cell-based craniofacial bone regeneration and subsequently we address the characteristics of various types of perinatal stem cells and their novel application in tissue engineering of craniofacial bone. We propose the promising feasibility and scope of perinatal stem cell-based craniofacial bone tissue engineering for future clinical application.

Human fibroblast‐derived extracellular matrix constructs for bone tissue engineering applications

We exploited the biomimetic approach to generate constructs composed of synthetic biphasic calcium phosphate ceramic and extracellular matrix (SBC-ECM) derived from adult human dermal fibroblasts in complete xeno-free culture conditions. The construct morphology and composition were assessed by scanning electron microscopy, histology, immunohistochemistry, Western blot, glycosaminoglycan, and hydroxyproline assays. Residual DNA quantification, endotoxin testing, and local inflammatory response after implantation in a rat critical-sized calvarial defect were used to access the construct biocompatibility. Moreover, in vitro interaction of human mesenchymal stem cells (hMSCs) with the constructs was studied. The bone marrow- and adipose tissue-derived mesenchymal stem cells were characterized by flow cytometry and tested for osteogenic differentiation capacity prior seeding onto SBC-ECM, followed by alkaline phosphatase, 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, and real-time quantitative polymerase chain reaction to assess the osteogenic differentiation of hMSCs after seeding onto the constructs at different time intervals. The SBC-ECM constructs enhanced osteogenic differentiation of hMSCs in vitro and exhibited excellent handling properties and high biocompatibility in vivo. Our results highlight the ability to generate in vitro fibroblast-derived ECM constructs in complete xeno-free conditions as a step toward clinical translation, and the potential use of SBC-ECM in craniofacial bone tissue engineering applications.

Craniofacial bone tissue engineering

There are numerous conditions, such as trauma, cancer, congenital malformations, and progressive deforming skeletal diseases, that can compromise the function and architectonics of bones of craniofacial region. The need to develop new approaches for treatment of these disorders arises from the fact that conventional therapeutic strategies face many obstacles and limitations. The use of tissue engineering in regeneration of craniofacial bone structures is a very promising possibility and a great challenge for researchers and practitioners. Developments in stem cell biology and engineering have led to the discovery of different stem cell populations and biodegradable materials with suitable properties. This review summarizes the current achievements in tissue engineering of craniofacial bone, temporomandibular joint, and periodontal ligament.

Bilateral Orbitozygomatic Reconstruction With Tissue-Engineered Bone

Critical defects of the craniomaxillofacial region and long bones are often treated with bone grafts and vascularized osteocutaneous free flaps. These lengthy operations may be associated with considerable donor site morbidity and often have suboptimal functional and aesthetic results. The allure of providing an exact replica of a missing bone that incorporates to become indistinguishable from self, has the capacity to heal and grow, is resistant to infection, and with minimal morbidity is a "holy grail" to all surgeons who work with bone. This is a report of a 14-year-old adolescent boy with Treacher Collins syndrome whose bilateral orbitozygomatic defects were treated with engineered bone made from a combination of human bone allograft, adipose-derived mesenchymal stem cells, bone morphogenic protein-2, and periosteal grafts. This single-stage reconstruction was followed by an exuberant amount of postoperative swelling that persisted for 3 weeks. He had slight lid malposition postoperatively as well but has had no long-term negative effects from the surgery. His reconstruction has remained stable during a 6-month follow-up, and a recent biopsy of the engineered bone demonstrated healthy, lamellar bone. These data are the first to demonstrate revitalization of large volume allograft bone in humans and have positive implications for craniofacial bone tissue engineering. The combination of adipose-derived stem cells, bone morphogenic protein-2, bone allograft, and periosteum may provide an alternative method to both osteocutaneous free flaps and large structural allografts with less morbidity and improved long-term results.