NZ-GMP Approved Serum Improve hDPSC Osteogenic Commitment and Increase Angiogenic Factor Expression

Angiogenic Potential of Various Oral Cavity-Derived Mesenchymal Stem Cells and Cell-Derived Secretome: A Systematic Review and Meta-Analysis

Recent evidence suggests the immense potential of human mesenchymal stem cell (hMSC) secretome conditioned medium-mediated augmentation of angiogenesis. However, angiogenesis potential varies from source and origin. The hMSCs derived from the oral cavity share an exceptional quality due to their origin from a hypoxic environment. Our systematic review aimed to compare the mesenchymal stem cells (MSCs) derived from various oral cavity sources and cell-derived secretomes, and evaluate their angiogenic potential. A literature search was conducted using PubMed and Scopus from January 2000 to September 2020. Source-wise outcomes were systematically analyzed using in vitro, in vivo, and in ovo studies, emphasizing endothelial cell migration, tube formation, and blood vessel formation. Ninety-four studies were included in the systematic review, out of which 4 studies were subsequently included in the meta-analysis. Prominent growth factors and other bioactive components implicated in improving angiogenesis were included in the respective studies. The findings suggest that oral tissues are a rich source of hMSCs. The meta-analysis revealed a positive correlation between dental pulp-derived MSCs (DPMSCs) and stem cells derived from apical papilla (SCAP) compared to human umbilical cord-derived endothelial cell lines as a control. It shows a statistically significant positive correlation between the co-culture of human umbilical vein endothelial cells (HUVECs) and DPMSCs with tubule length formation and total branching points. Our meta-analysis revealed that oral-derived MSCs (dental pulp stem cells and SCAP) carry a better angiogenic potential in vitro than endothelial cell lines alone. The reviewed literature illustrates that oral cavity-derived MSCs (OC-MSCs) increased angiogenesis. The present literature reveals a dearth of investigations involving sources other than dental pulp. Even though OC-MSCs have revealed more significant potential than other MSCs, more comprehensive, target-oriented interinstitutional prospective studies are warranted to determine whether oral cavity-derived stem cells are the most excellent sources of significant angiogenic potential.

Dense carbon-nanotube coating scaffolds stimulate osteogenic differentiation of mesenchymal stem cells

Carbon nanotubes (CNTs) have desirable mechanical properties for use as biomaterials in orthopedic and dental area such as bone- and tooth- substitutes. Here, we demonstrate that a glass surface densely coated with single-walled carbon nanotubes (SWNTs) stimulate the osteogenic differentiation of rat bone marrow mesenchymal stem cells (MSCs). MSCs incubated on SWNT- and multi-walled carbon nanotube (MWNT)-coated glass showed high activities of alkaline phosphatase that are markers for early stage osteogenic differentiation. Expression of Bmp2, Runx2, and Alpl of MSCs showed high level in the early stage for MSC incubation on SWNT- and MWNT-coated surfaces, but only the cells on the SWNT-coated glass showed high expression levels of Bglap (Osteocalcin). The cells on the SWNT-coated glass also contained the most calcium, and their calcium deposits had long needle-shaped crystals. SWNT coating at high density could be part of a new scaffold for bone regeneration.

S, Hegde A, ES SP, Johnson RP, Das SP, Vazirally S, Rekha PD. Effect of calcium glucoheptonate on proliferation and osteogenesis of osteoblast-like cells in vitro

Calcium is the key macromineral having a role in skeletal structure and function, muscle contraction, and neurotransmission. Bone remodeling is maintained through a constant balance between calcium resorption and deposition. Calcium deficiency is resolved through calcium supplementation, and among the supplements, water-soluble organic molecules attracted great pharmaceutical interest. Calcium glucoheptonate is a highly water-soluble organic calcium salt having clinical use; however, detailed investigations on its biological effects are limited. We assessed the effects of calcium glucoheptonate on cell viability and proliferation of osteoblast-like MG-63 cells. Calcium uptake and mineralization were evaluated using Alizarin red staining of osteoblast-like MG-63 cells treated with calcium glucoheptonate. Expression of osteogenic markers were monitored by western blotting, immunofluorescence, and qRT-PCR assays. Increased proliferation and calcium uptake were observed in the MG-63 cells treated with calcium glucoheptonate. The treatment also increased the expression of osteopontin and osteogenic genes such as collagen-1, secreted protein acidic and cysteine rich (SPARC), and osteocalcin. Calcium glucoheptonate treatment did not exert any cytotoxicity on colorectal and renal epithelial cells, indicating the safety of the treatment. This is the first report with evidence for its beneficial effect for pharmaceutical use in addressing calcium deficiency conditions.

Bone regeneration in Ds-Red pig calvarial defect using allogenic transplantation of EGFP-pMSCs - A comparison of host cells and seeding cells in the scaffold

Background

Cells, scaffolds, and factors are the triad of regenerative engineering; however, it is difficult to distinguish whether cells in the regenerative construct are from the seeded cells or host cells via the host blood supply. We performed a novel in vivo study to transplant enhanced green fluorescent pig mesenchymal stem cells (EGFP-pMSCs) into calvarial defect of DsRed pigs. The cell distribution and proportion were distinguished by the different fluorescent colors through the whole regenerative period.

Method/Results

Eight adult domestic Ds-Red pigs were treated with five modalities: empty defects without scaffold (group 1); defects filled only with scaffold (group 2); defects filled with osteoinduction medium-loaded scaffold (group 3); defects filled with 5 x 10³ cells/scaffold (group 4); and defects filled with 5 x 10⁴ cells/scaffold (group 5). The in vitro cell distribution, morphology, osteogenic differentiation, and fluorescence images of groups 4 and 5 were analyzed. Two animals were sacrificed at 1, 2, 3, and 4 weeks after transplantation. The in vivo fluorescence imaging and quantification data showed that EGFP-pMSCs were represented in the scaffolds in groups 4 and 5 throughout the whole regenerative period. A higher seeded cell density resulted in more sustained seeded cells in bone regeneration compared to a lower seeded cell density. Host cells were recruited by seeded cells if enough space was available in the scaffold. Host cells in groups 1 to 3 did not change from the 1st week to 4th week, which indicates that the scaffold without seeded cells cannot recruit host cells even when enough space is available for cell ingrowth. The histological and immunohistochemical data showed that more cells were involved in osteogenesis in scaffolds with seeded cells.

Conclusion

Our in vivo results showed that more seeded cells recruit more host cells and that both cell types participate in osteogenesis. These results suggest that scaffolds without seeded cells may not be effective in bone transplantation.

Effects of mineral trioxide aggregate, calcium hydroxide, biodentine and Emdogain on osteogenesis, Odontogenesis, angiogenesis and cell viability of dental pulp stem cells

BACKGROUND

Vital pulp therapy preserves and maintains the integrity and the health of dental pulp tissue that has been injured by trauma, caries or restorative procedures. The enhancement of cells viability and formation of reparative dentine and new blood vessels are vital determinants of the success of direct pulp capping. Therefore, the aims of this study was to evaluate and compare the in vitro osteogenic, odontogenic and angiogenic effects of mineral trioxide aggregate (MTA), calcium hydroxide [Ca(OH)₂], Biodentine and Emdogain on dental pulp stem cells (DPSCs) and examine the effects of the tested materials on cell viability.

METHODS

DPSCs were treated with MTA, Ca(OH)₂, Biodentine or Emdogain. Untreated cells were used as control. The cell viability was measured by MTT assay on day 3. Real-Time PCR with SYBR green was used to quantify the gene expression levels of osteogenic markers (alkaline phosphatase and osteopontin), odontogenic marker (dentin sialophosphoprotein) and angiogenic factor (vascular endothelial growth factor) on day 7 and day 14.

RESULTS

All capping materials showed variable cytotoxicity against DPSCs (77% for Emdogain, 53% for MTA, 26% for Biodentine and 16% for Ca(OH)₂ compared to control (P value < 0.0001). Osteopontin (OPN) and dentin sialophosphoprotein (DSPP) gene expression was increased by all four materials. However, alkaline phosphatase (ALP) was upregulated by all materials except Emdogain. Vascular endothelial growth factor (VEGF) expression was upregulated by all four tested materials except Ca(OH)₂.

CONCLUSIONS

Our results suggest MTA, Biodentine and Emdogain exhibit similar attributes and may score better than Ca(OH)₂. Emdogain could be a promising alternative to MTA and Biodentine in enhancing pulp repair capacity following dental pulp injury. However, further future research is required to assess the clinical outcomes and compare it with the in vitro findings.

Systemically transplanted mesenchymal stem cells induce vascular-like structure formation in a rat model of vaginal injury

The beneficial effect of mesenchymal stem cells (MSCs) on wound healing is mostly attributed to a trophic effect that promotes angiogenesis. Whether MSCs can contribute to the formation of new blood vessels by direct differentiation is still controversial. Pelvic floor dysfunction (PFD) is a group of disorders that negatively affect the quality of women's lives. Traditional vaginal surgical repair provides disappointing anatomical outcome. Stem cell transplantation may be used to supplement surgery and improve its outcome. Here we aimed to examine the engraftment, survival, differentiation and angiogenic effect of transplanted MSCs in a vaginal injury rat model. MSCs were obtained from the bone marrow of Sprague Drawley (SD) rats, expanded and characterized in vitro. The MSCs expressed CD90 and CD29, did not express CD45, CD34, CD11b and CD31 and could differentiate into osteogenic, chondrogenic and adipogenic lineages. Cells were labeled with either PKH-26 or GFP and transplanted systemically or locally to female SD rats, just after a standardized vaginal incision was made. Engraftment after local transplantation was less efficient at all-time points compared to systemic administration. In the systemically transplanted animal group, MSCs migrated to the injury site and were present in the healed vagina for at least 30 days. Both systemic and local MSCs transplantation promoted host angiogenesis. Systemically transplanted MSCs created new vascular-like structures by direct differentiation into endothelium. These findings pave the way to further studies of the potential role of MSCs transplantation in improving surgical outcome in women with PFD.

Curcumin/Liposome Nanotechnology as Delivery Platform for Anti-inflammatory Activities via NFkB/ERK/pERK Pathway in Human Dental Pulp Treated With 2-HydroxyEthyl MethAcrylate (HEMA)

Curcumin, primary component of the spice turmeric extracted from the rhizomes of Curcuma longa, represents the major anti-oxidant and anti-inflammatory substance found in turmeric, acting thought various mechanisms not completely understood. Curcumin modulates cytokines, growth factors, transcription factors, inflammatory molecules and cell signaling pathways. During restorative dentistry practice, free resin monomers of 2-hydroxyethyl methacrylate (HEMA) propagate through dentin micro-channel and pulp into the bloodstream affecting cellular integrity. The study highlights the significance of application of curcumin bioactive component into liposomal formulations (CurLIP) to restore the homeostasis of dental pulp stem cells (hDPSCs) in response to 3 and 5 mmol L^–1 HEMA treatment. Cell proliferation in combination with changes of the morphological features, proinflammatory cytokines secretion as Interleukin (IL) 6, IL8, Monocyte Chemoattractant Protein-1 (MCP1) and Interferon-gamma (IFNγ) were assayed along with the nuclear factor (NF)-kB, an inducible transcription factor involved in the activation of several cell processes associated to extracellular signal-regulated kinases (ERK) and posphorylated (p-) ERK pathway. Our results showed a decreased cell proliferation, morphological changes and upregulation of IL6, IL8, MCP1 and IFNγ in presence of 3 and 5 mmol L^–1 HEMA treatment. CurLIP therapy in hDPSCs provokes an increase in cell proliferation and the block of inflammatory cytokines secretion through the inhibitory regulation of NFkB/ERK and pERK signaling cascade. The natural nanocarrier CurLIP influences numerous biochemical and molecular cascades causing anti-inflammatory properties in response to HEMA treatment in human dental pulp stem cells, representing an innovative endodontic formulation able to improve the quality of dental care with a major human community impact.

Autologous adipose-derived stem cell transplantation enhances healing of wound with exposed bone in a rat model

OBJECTIVES

Soft tissue wounds with exposed bone often require extended healing times and can be associated with severe complications. We describe the ability of artificial dermis with autogenic adipose-derived stem cells (ADSCs) to promote the healing of wounds with exposed bone in a rat model.

METHODS

Adipose tissues harvested from the bilateral inguinal regions of Wistar rats were used as ADSCs. Rats were randomly divided into control and ADSC groups to investigate the efficacy of ADSC transplantation for wound healing (n = 20 per group). Soft tissue defects were created on the heads of the rats and were covered with artificial dermis with or without the seeded ADSCs. Specimens from these rats were evaluated using digital image analysis, histology, immunohistochemistry, cell labeling, and real-time reverse-transcription polymerase chain reaction (real-time RT-PCR).

RESULTS

The average global wound area was significantly smaller in the ADSC group than in the control group on days 3, 7, and 14 after surgery (p<0.05). After 14 days, the blood vessel density in the wound increased by 1.6-fold in the ADSC group compared with that in the control group (p<0.01). Real-time RT-PCR results showed higher Fgfb and Vegf expression levels at all time points, and higher Tgfb1 and Tgfb3 expression levels until 14 days after surgery in the ADSC group than in the control group (p<0.05).

CONCLUSIONS

In wounds with exposed bone, autogenic ADSCs can promote vascularization and wound healing. Use of this cell source has multiple benefits, including convenient clinical application and lack of ethical concerns.

Dentin tubule orientation determines odontoblastic differentiation in vitro: A morphological study

Odontoblasts are post-mitotic cells responsible for maintenance of the dentin, and are therefore important for dental health. In some cases, irreversible pulpitis leads to necrosis and consequently death of odontoblasts. Regenerative endodontics (RE) uses the concept of tissue engineering to restore the root canals to a healthy state, allowing for continued development of the root and surrounding tissue. Human dental pulp stem cells (hDPSCs) have been successfully used in RE to restore odontoblast function. Surface microgeometry is one of the most important factors involved in the induction of differentiation of hDPSCs into odontoblast-like cells. Although different authors have demonstrated the importance of a dentin-like surface with accessible dentin tubules to induce differentiation of hDPSCs, the ultrastructural characteristics of the cells and the secreted extracellular matrix have not been studied in depth. Here, we used an acellular dentin scaffold containing dentin tubules in different spatial geometries, which regulated their accessibility to cells. hDPSCs were cultured on the scaffolds for up to 6 weeks. Systematic characterization of differentiated cells was performed using both optical (hematoxylin and eosin, Masson trichrome, and immunohistochemical determination of dentin sialoprotein [DSSP]) and transmission electron microscopy. The results presented here indicated that cells grown on the dentin surface containing accessible dentin tubules developed a characteristic odontoblastic phenotype, with cellular processes similar to native odontoblasts. The cell organization and characteristics of secreted extracellular matrix were also similar to those of native dentin tissue. Cells grown on non-accessible dentin tubule surfaces secreted a more abundant and dense extracellular matrix, and developed a different phenotype consisting of secretory flat cells organized in layers. Cells grown far from the scaffold, i.e., directly on the culture well surface, developed a secretory phenotype probably influenced by biochemical factors released by the dentin scaffold or differentiated cells. The results presented here support the use of hDPSCs to regenerate dentin and show the utility of scaffold microgeometry for determining the differentiation and secretory phenotype of cultured cells.

Dental derived stem cell conditioned media for hair growth stimulation

Alopecia is a clinical condition caused by excessive hair loss which may result in baldness, the causes of which still remain elusive. Conditioned media (CM) from stem cells shows promise in regenerative medicine. Our aim was to evaluate the potential CM of dental pulp stem cells obtained from human deciduous teeth (SHED-CM) to stimulate hair growth under in vitro and in vivo conditions. SHED and hair follicle stem cells (HFSCs) (n = 3) were cultured in media combinations; i) STK2, ii) DMEM-KO+10% FBS, iii) STK2+2% FBS and profiled for the presence of positive hair growth-regulatory paracrine factors; SDF-1, HGF, VEGF-A, PDGF-BB and negative hair growth-regulatory paracrine factors; IL-1α, IL-1β, TGF-β, bFGF, TNF-α, and BDNF. The potential of CM from both cell sources to stimulate hair growth was evaluated based on the paracrine profile and measured dynamics of hair growth under in vitro conditions. The administration of CM media to telogen-staged synchronized 7-week old C3H/HeN female mice was carried out to study the potential of the CM to stimulate hair growth in vivo. SHED and HFSCs cultured in STK2 based media showed a shorter population doubling time, higher viability and better maintenance of MSC characteristics in comparison to cells cultured in DMEM-KO media. STK2 based CM contained only two negative hair growth-regulatory factors; TNF-α, IL-1 while DMEM-KO CM contained all negative hair growth-regulatory factors. The in vitro study confirmed that treatment with STK2 based media CM from passage 3 SHED and HFSCs resulted in a significantly higher number of anagen-staged hair follicles (p<0.05) and a significantly lower number of telogen-staged hair follicles (p<0.05). Administration of SHED-CM to C3H/HeN mice resulted in a significantly faster stimulation of hair growth in comparison to HFSC-CM (p<0.05), while the duration taken for complete hair coverage was similar for both CM sources. Thus, SHED-CM carries the potential to stimulate hair growth which can be used as a treatment tool for alopecia.

PTH decreases in vitro human cartilage regeneration without affecting hypertrophic differentiation

Regenerated cartilage formed after Autologous Chondrocyte Implantation may be of suboptimal quality due to postulated hypertrophic changes. Parathyroid hormone-related peptide, containing the parathyroid hormone sequence (PTHrP 1–34), enhances cartilage growth during development and inhibits hypertrophic differentiation of mesenchymal stromal cells (MSCs) and growth plate chondrocytes. This study aims to determine the possible anabolic and/or hypertrophic effect of PTH on human articular chondrocytes. Healthy human articular cartilage-derived chondrocytes (n = 6 donors) were cultured on type II collagen-coated transwells with/without 0.1 or 1.0 μM PTH from day 0, 9, or 21 until the end of culture (day 28). Extracellular matrix production, (pre)hypertrophy and PTH signaling were assessed by RT-qPCR and/or immunohistochemistry for collagen type I, II, X, RUNX2, MMP13, PTHR1 and IHH and by determining glycosaminoglycan production and DNA content. The Bern score assessed cartilage quality by histology. Regardless of the concentration and initiation of supplementation, PTH treatment significantly decreased DNA and glycosaminoglycan content and reduced the Bern score compared with controls. Type I collagen deposition was increased, whereas PTHR1 expression and type II collagen deposition were decreased by PTH supplementation. Expression of the (pre)hypertrophic markers MMP13, RUNX2, IHH and type X collagen were not affected by PTH. In conclusion, PTH supplementation to healthy human articular chondrocytes did not affect hypertrophic differentiation, but negatively influenced cartilage quality, the tissues’ extracellular matrix and cell content. Although PTH may be an effective inhibitor of hypertrophic differentiation in MSC-based cartilage repair, care may be warranted in applying accessory PTH treatment due to its effects on articular chondrocytes.

Adipose-derived stem cell sheets accelerate bone healing in rat femoral defects

In the present study, we investigated whether both adipose-derived stem cell (ADSC) and osteogenic-induced ADSC sheets could promote bone healing in a rat distal femoral metaphysis bone defect model. A through-hole defect of 1 mm diameter was drilled into each distal femur of 12 week old rats. Forty-five rats were randomly assigned to three groups: (1) control group; (2) ADSC sheet group; or (3) osteogenic-induced ADSC sheet group. We evaluated each group by analysis of computerized tomography scans every week after the surgery, histological analysis, and DiI labeling (a method of membrane staining for post implant cell tracing). Radiological and histological evaluations showed that a part of the hole persisted in the control group at four weeks after surgery, whereas the hole was restored almost completely by new bone formation in both sheet groups. The mean value of bone density (in Houndsfield units) for the bone defect area was significantly higher in both sheet groups than that in the control group (p = 0.05) at four weeks postoperative. A large number of osteocalcin positive osteoblasts were observed at the area of bone defect, especially in the osteogenic-induced ADCS sheet group. DiI labeling in the newly formed bone showed that each sheet had differentiated into bone tissue at four weeks after surgery. The ADSC and the osteogenic-induced ADSC sheets promoted significantly quicker bone healing in the bone defect. Moreover, the osteogenic-induced ADSC sheet may be more advantageous for bone healing than the ADSC sheet because of the higher number of osteocalcin positive osteoblasts via the transplantation.

Tenogenic differentiation protocol in xenogenic-free media enhances tendon-related marker expression in ASCs

Adipose-derived stem cells (ASCs) are multipotent and immune-privileged mesenchymal cells, making them ideal candidates for therapeutic purposes to manage tendon disorders. Providing safe and regulated cell therapy products to patients requires adherence to good manufacturing practices. To this aim we investigated the in vitro tenogenic differentiation potential of ASCs using a chemically defined serum-free medium (SF) or a xenogenic-free human pooled platelet lysate medium (hPL) suitable for cell therapy and both supplemented with CTGF, TGFβ-3, BMP-12 and ascorbic acid (AA) soluble factors. Human ASCs were isolated from 4 healthy donors and they were inducted to differentiate until 14 days in both hPL and SF tenogenic media (hPL-TENO and SF-TENO). Cell viability and immunophenotype profile were analysed to evaluate mesenchymal stem cell (MSC) characteristics in both xenogenic-free media. Moreover, the expression of stemness and tendon-related markers upon cell differentiation by RT-PCR, protein staining and cytofluorimetric analysis were also performed. Our results showed the two xenogenic-free media well support cell viability of ASCs and maintain their MSC nature as demonstrated by their typical immunophenototype profile and by the expression of NANOG, OCT4 and Ki67 genes. Moreover, both hPL-TENO and SF-TENO expressed significant high levels of the tendon-related genes SCX, COL1A1, COL3A1, COMP, MMP3 and MMP13 already at early time points in comparison to the respective controls. Significant up-regulations in scleraxis, collagen and tenomodulin proteins were also demonstrated at in both differentiated SF and hPL ASCs. In conclusion, we demonstrated firstly the feasibility of both serum and xenogenic-free media tested to culture ASCs moving forward the GMP-compliant approaches for clinical scale expansion of human MSCs needed for therapeutical application of stem cells. Moreover, a combination of CTGF, BMP-12, TGFβ3 and AA factors strongly and rapidly induce human ASCs to differentiate into tenocyte-like cells.

Calcium mimics the chemotactic effect of conditioned media and is an effective inducer of bone regeneration

Background

After bone resorption, ions and degraded organic components are co-released into the extracellular space. Ions and growth factors, although different in their biological nature, induce a common and coordinated chemotactic effect. Conditioned media has been used successfully in bone regeneration by promoting endogenous cell recruitment. Likewise, calcium alone act as a paracrine chemotactic signal, inducing the host’s undifferentiated progenitor cell infiltration into the implanted biomaterials. The aim of the present study was to compare the chemotactic effect of calcium and conditioned media in primary calvarial cells.

Methods

The chemotactic cell response was evaluated in vitro using an agarose spot and a wound healing assay. In addition, we used a calvarial bone explant model ex-vivo. The healing potential was also tested through an in vivo model, a critical-size calvarial bone defect in mice. For the in vivo experiment, cell-free calcium-containing or conditioned media-containing scaffolds were implanted, and MSC’s seeded scaffolds were used as positive control. After seven weeks post-implantation, samples were retrieved, and bone regeneration was evaluated by μCT and histological analysis. Osteogenic gene expression was evaluated by qPCR.

Results

We found that chemotactic cell migration in response to either calcium or conditioned media was equivalent in vitro and ex vivo. Accordingly, μCT analysis showed that bone regeneration induced by the MSC’s seeded scaffolds was similar to that obtained with cell-free calcium or conditioned media-containing scaffolds. Pre-treatment with SB202190, a highly selective p38 inhibitor, abrogated the chemotactic effect induced by conditioned media. In contrast, p38 activity was not essential for the calcium-induced chemotaxis. Moreover, BAPTA-AM treatment, a cytosolic calcium chelator, decreased the chemotactic effect and the expression of key osteogenic genes induced by calcium or conditioned media.

Conclusion

We show that calcium ions alone not only mimic the conditioned media chemotactic effect, but also induce an osteogenic effect similar to that produced by transplanted MSC’s in vivo. Furthermore, the chemotactic effect induced by conditioned media is calcium and p38 dependent. The rise in cytosolic calcium might integrate the different signaling pathways triggered by conditioned media and extracellular Ca²⁺. This calcium-driven in situ bone regeneration is a promising and convenient alternative to promote endogenous cell recruitment into the injured bone site. This pre-clinical cell-free and growth factor-free approach might avoid the disadvantages of the ex vivo cell manipulation.

Dental pulp-derived stem cell conditioned medium to regenerate peripheral nerves in a novel animal model of dysphagia

In nerve regeneration studies, various animal models are used to assess nerve regeneration. However, because of the difficulties in functional nerve assessment, a visceral nerve injury model is yet to be established. The superior laryngeal nerve (SLN) plays an essential role in swallowing. Although a treatment for SLN injury following trauma and surgery is desirable, no such treatment is reported in the literature. We recently reported that stem cells derived from human exfoliated deciduous teeth (SHED) have a therapeutic effect on various tissues via macrophage polarization. Here, we established a novel animal model of SLN injury. Our model was characterized as having weight loss and drinking behavior changes. In addition, the SLN lesion caused a delay in the onset of the swallowing reflex and gain of laryngeal residue in the pharynx. Systemic administration of SHED-conditioned media (SHED-CM) promoted functional recovery of the SLN and significantly promoted axonal regeneration by converting of macrophages to the anti-inflammatory M2 phenotype. In addition, SHED-CM enhanced new blood vessel formation at the injury site. Our data suggest that the administration of SHED-CM may provide therapeutic benefits for SLN injury.

MicroRNA 210 Mediates VEGF Upregulation in Human Periodontal Ligament Stem Cells Cultured on 3DHydroxyapatite Ceramic Scaffold

The aim of the present research was the evaluation of the behavior of human periodontal ligament stem cells (hPDLSCs), cultured in presence of Endobon^® Xenograft Granules (G), a fully deproteinated hydroxyapatite ceramic scaffold derived from cancellous bovine bone. hPDLSCs were seeded with and without G for 24 h to 1 week. The cell growth, morphological features, adhesiveness, differentiation ability, modulation of miR-210 and Vascular Endothelial Growth Factor (VEGF) secretion were analyzed by means of MTT assay, Scanning Electron Microscopy (SEM), Confocal Laser Scanning Microscopy (CLSM), Alizarin Red S assay, RT-PCR and ELISA test, respectively. hPDLSCs grown on the biomaterial showed the ability to form focal adhesion on the substrate, as demonstrated by vinculin expression. These data were supported by SEM analysis showing that an adhesiveness process associated to cell growth occurs between cells and biomaterials. The osteogenic differentiation, evaluated by morphological, biochemical, and RT-PCR analysis, was pronounced in the hPDLSCs grown in the three-dimensional inorganic bovine bone substitute in the presence of osteoinductive conditions. In addition, an upregulation of miR-210 and VEGF was evident in cells cultured in presence of the biomaterial. Our results inspire us to consider granules not only an adequate biocompatible three-dimensional biomaterial, but also an effective inductor of miR-210 and VEGF; in fact, the involvement of miR-210 in VEGF secretion could offer a novel regulatory system in the early steps of the bone-regeneration process.

Osteoconductive Microarchitecture of Bone Substitutes for Bone Regeneration Revisited

In the last three decades, all efforts in bone tissue engineering were driven by the dogma that the ideal pore size in bone substitutes lies between 0.3 and 0.5 mm in diameter. Newly developed additive manufacturing methodologies for ceramics facilitate the total control over pore size, pore distribution, bottleneck size, and bottleneck distribution. Therefore, this appears to be the method of choice with which to test the aforementioned characteristics of an ideal bone substitute. To this end, we produced a library of 15 scaffolds with diverse defined pore/bottleneck dimensions and distributions, tested them in vivo in a calvarial bone defect model in rabbits, and assessed the clinically most relevant parameters: defect bridging and bony regenerated area. Our in vivo data revealed that the ideal pore/bottleneck dimension for bone substitutes is in the range of 0.7-1.2 mm, and appears therefore to be twofold to fourfold more extended than previously thought. Pore/bottleneck dimensions of 1.5 and 1.7 mm perform significantly worse and appear unsuitable in bone substitutes. Thus, our results set the ideal range of pore/bottleneck dimensions and are likely to have a significant impact on the microarchitectural design of future bone substitutes for use in orthopedic, trauma, cranio-maxillofacial and oral surgery.

Stem Cells from Dental Pulp: What Epigenetics Can Do with Your Tooth

Adult stem cells have attracted scientific attention because they are able to self-renew and differentiate into several specialized cell types. In this context, human dental tissue-derived mesenchymal stem cells (hDT-MSCs) have emerged as a possible solution for repairing or regenerating damaged tissues. These cells can be isolated from primary teeth that are naturally replaced, third molars, or other dental tissues and exhibit self-renewal, a high proliferative rate and a great multilineage potential. However, the cellular and molecular mechanisms that determine lineage specification are still largely unknown. It is known that a change in cell fate requires the deletion of existing transcriptional programs, followed by the establishment of a new developmental program to give rise to a new cell lineage. Increasing evidence indicates that chromatin structure conformation can influence cell fate. In this way, reversible chemical modifications at the DNA or histone level, and combinations thereof can activate or inactivate cell-type-specific gene sequences, giving rise to an alternative cell fates. On the other hand, miRNAs are starting to emerge as a possible player in establishing particular somatic lineages. In this review, we discuss two new and promising research fields in medicine and biology, epigenetics and stem cells, by summarizing the properties of hDT-MSCs and highlighting the recent findings on epigenetic contributions to the regulation of cellular differentiation.