Exfoliated Human Deciduous Tooth Stem Cells Incorporating Carbonate Apatite Scaffold Enhance BMP-2, BMP-7 and Attenuate MMP-8 Expression During Initial Alveolar Bone Remodeling in Wistar Rats (Rattus norvegicus)

Dental pulp stem cells - A basic research and future application in regenerative medicine

Dental pulp is a valuable and accessible source of stem cells (DPSCs) with characteristics similar to mesenchymal stem cells. DPSCs can regenerate a range of tissues and their potential for clinical application in regenerative medicine is promising. DPSCs have been found to express low levels of Class II HLA-DR (MHC) molecules, making them potential candidates for allogeneic transplantation without matching the donor's tissue. Research on the correlation between non-coding RNAs (ncRNAs) and human dental pulp stem cells (DPSCs) provides promising insights into the use of these cells in clinical settings for a wide range of medical conditions. It is possible to use a number of ncRNAs in order to restore the functional role of downregulated ncRNAs that are correlated with osteoblastogenesis, or to suppress the functional role of overexpressed ncRNAs associated with osteoclast differentiation in some cases.

A review of the therapeutic potential of dental stem cells as scaffold-free models for tissue engineering application

In the realm of regenerative medicine, tissue engineering has introduced innovative approaches to facilitate tissue regeneration. Specifically, in pulp tissue engineering, both scaffold-based and scaffold-free techniques have been applied. Relevant articles were meticulously chosen from PubMed, Scopus, and Google Scholar databases through a comprehensive search spanning from October 2022 to December 2022. Despite the inherent limitations of scaffolding, including inadequate mechanical strength for hard tissues, insufficient vents for vessel penetration, immunogenicity, and suboptimal reproducibility-especially with natural polymeric scaffolds-scaffold-free tissue engineering has garnered significant attention. This methodology employs three-dimensional (3D) cell aggregates such as spheroids and cell sheets with extracellular matrix, facilitating precise regeneration of target tissues. The choice of technique aside, stem cells play a pivotal role in tissue engineering, with dental stem cells emerging as particularly promising resources. Their pluripotent nature, non-invasive extraction process, and unique properties render them highly suitable for scaffold-free tissue engineering. This study delves into the latest advancements in leveraging dental stem cells and scaffold-free techniques for the regeneration of various tissues. This paper offers a comprehensive summary of recent developments in the utilization of dental stem cells and scaffold-free methods for tissue generation. It explores the potential of these approaches to advance tissue engineering and their effectiveness in therapies aimed at tissue regeneration.

Ultrasound-Targeted Microbubble Destruction Increases BBB Permeability and Promotes Stem Cell-Induced Regeneration of Stroke by Downregulating MMP8

The objective of this study was to evaluate the feasibility, safety, and effectiveness of intravenous stem cell delivery utilizing ultrasound-targeted microbubble destruction (UTMD) in a rat model of middle cerebral artery occlusion (MCAO), while investigating the underlying mechanisms. Acute cerebral infarction (ACI) was induced surgically in adult rats to create the MCAO rat model. Intravenous injection of SonoVue microbubbles and bone marrow-derived mesenchymal stem cells (BMSC) was performed concurrently, with or without ultrasound targeting the stroke. The animals were divided into four groups: sham-operated group, ACI-MCAO rats treated with phosphate-buffered saline (ACI+PBS), rats receiving intravenous delivery of BMSC expressing green fluorescent protein (GFP-BMSC; ACI+BMSC), and rats receiving intravenous GFP-BMSC with simultaneous UTMD exposure (ACI+BMSC+UTMD). The efficacy of the treatments was assessed by evaluating the animals' neurological function using the Longa score and examining histopathological changes such as cerebral infarct volume, cerebral edema, and cell apoptosis. A rat cytokine array was utilized to identify the potential cytokines that may be responsible for the therapeutic effect of UTMD-mediated BMSC treatment. Optimal UTMD parameters resulted in an increase in blood-brain barrier (BBB) permeability after 30 min, which returned to baseline 72 h later without causing any residual injury. UTMD application significantly increased the homing of intravenously delivered BMSC, resulting in a 2.2-fold increase in GFP-BMSC cell count on day 3 and a 2.6-fold increase on day 7 compared with intravenous delivery alone. This effect persisted for up to 6 weeks after injection. Intravenous BMSC delivery significantly reduced the volume of cerebral infarct and decreased cerebral edema, leading to a lower Longa score. Furthermore, this effect was further enhanced by UTMD. Acute cerebral infarction induced by MCAO led to elevated matrix metalloproteinase 8 (MMP8) levels in the cerebrospinal fluid, which were significantly reduced following UTMD-mediated BMSC treatment. Ultrasound-targeted microbubble destruction facilitates the migration and homing of BMSC into the brain, possibly by transiently increasing blood-brain barrier (BBB) permeability, thereby improving therapeutic outcomes in an ACI rat model. The observed effect may be partly attributed to modulation of MMP8 levels.Advances in knowledge: UTMD-mediated intravenously delivered BMSC transplantation led to a significant increase in cell homing and reduction of MMP8 levels, resulting in increased therapeutic effect in an acute ischemic cerebral infarction model.

Evaluating the efficacy of human dental pulp stem cells and scaffold combination for bone regeneration in animal models: a systematic review and meta-analysis

INTRODUCTION

Human adult dental pulp stem cells (hDPSC) and stem cells from human exfoliated deciduous teeth (SHED) hold promise in bone regeneration for their easy accessibility, high proliferation rate, self-renewal and osteogenic differentiation capacity. Various organic and inorganic scaffold materials were pre-seeded with human dental pulp stem cells in animals, with promising outcomes in new bone formation. Nevertheless, the clinical trial for bone regeneration using dental pulp stem cells is still in its infancy. Thus, the aim of this systematic review and meta-analysis is to synthesise the evidence of the efficacy of human dental pulp stem cells and the scaffold combination for bone regeneration in animal bone defect models.

METHODOLOGY

This study was registered in PROSPERO (CRD2021274976), and PRISMA guideline was followed to include the relevant full-text papers using exclusion and inclusion criteria. Data were extracted for the systematic review. Quality assessment and the risk of bias were also carried out using the CAMARADES tool. Quantitative bone regeneration data of the experimental (scaffold + hDPSC/SHED) and the control (scaffold-only) groups were also extracted for meta-analysis.

RESULTS

Forty-nine papers were included for systematic review and only 27 of them were qualified for meta-analysis. 90% of the included papers were assessed as medium to low risk. In the meta-analysis, qualified studies were grouped by the unit of bone regeneration measurement. Overall, bone regeneration was significantly higher (p < 0.0001) in experimental group (scaffold + hDPSC/SHED) compared to the control group (scaffold-only) (SMD: 1.863, 95% CI 1.121-2.605). However, the effect is almost entirely driven by the % new bone formation group (SMD: 3.929, 95% CI 2.612-5.246) while % BV/TV (SMD: 2.693, 95% CI - 0.001-5.388) shows a marginal effect. Dogs and hydroxyapatite-containing scaffolds have the highest capacity in % new bone formation in response to human DPSC/SHED. The funnel plot exhibits no apparent asymmetry representing a lack of remarkable publication bias. Sensitivity analysis also indicated that the results generated in this meta-analysis are robust and reliable.

CONCLUSION

This is the first synthesised evidence showing that human DPSCs/SHED and scaffold combination enhanced bone regeneration highly significantly compared to the cell-free scaffold irrespective of scaffold type and animal species used. So, dental pulp stem cells could be a promising tool for treating various bone diseases, and more clinical trials need to be conducted to evaluate the effectiveness of dental pulp stem cell-based therapies.

Mechanisms of bone remodeling and therapeutic strategies in chronic apical periodontitis

Chronic periapical periodontitis (CAP) is a typical oral disease in which periodontal inflammation caused by an odontogenic infection eventually leads to bone loss. Uncontrolled infections often lead to extensive bone loss around the root tip, which ultimately leads to tooth loss. The main clinical issue in the treatment of periapical periodontitis is the repair of jawbone defects, and infection control is the first priority. However, the oral cavity is an open environment, and the distribution of microorganisms through the mouth in jawbone defects is inevitable. The subversion of host cell metabolism by oral microorganisms initiates disease. The presence of microorganisms stimulates a series of immune responses, which in turn stimulates bone healing. Given the above background, we intended to examine the paradoxes and connections between microorganisms and jaw defect repair in anticipation of new ideas for jaw defect repair. To this end, we reviewed the microbial factors, human signaling pathways, immune cells, and cytokines involved in the development of CAP, as well as concentrated growth factor (CGF) and stem cells in bone defect repair, with the aim of understanding the impact of microbial factors on host cell metabolism to inform the etiology and clinical management of CAP.

Evaluation of the multiple tissue factors in bone of primary osteoplasty and rhinoplasty in patients affected by cleft lip palate

Clefts of the lip and/or palate (CLP) are visible disruptions of standard facial structure. The aim of our study was to determine a relative number and appearance of the tissue factors in bone of patients with CLP during first time plastic alveolar osteoplasty or rhinoplasty. Immunohistochemistry was performed with matrix metalloproteinase-8 (MMP-8), matrix metalloproteinase-9 (MMP-9), osteopontin (OPN), osteocalcin (OC), Runt-related transcription factor 2 (Runx2), beta-defensin-2 (βdef-2), beta-defensin-3 (βdef-3), interleukin-1 alpha (IL-1α), and interleukin-10 (IL-10). The bone formation was observed by Masson-trichrome (Masson) staining. For the quantification of structures, the semi-quantitative census method was used. Spearman rank order correlation coefficient and Mann-Whitney U test were used for the statistical analysis. A significantly higher number of OPN positive osteocytes was observed in the CLP group when compared to the control group (p=0.002). The number of OC positive osteocytes (p=0.000) and βdef-2 positive osteocytes (p=0.003) was significantly lower in the CLP group in comparison to the control group. Strong, positive correlations between IL-10 and OC (rs=0.608; p=0.002), IL-1α and MMP-9 (rs=0.666; p=0.000), OPN and MMP-8 (rs=0.620; p=0.002) were detected in the CLP group. A tendency for the increased appearance of MMP-8, MMP-9 positive osteocytes of the patients with CLP, suggests elevated tissue remodelling properties. Increased appearance of OPN positive osteocytes in bone of the patients with CLP shows increased bone homeostasis based on seriously decreased mineralization, which may be a possible compensatory reaction to decreased quality of postsurgical bone.

Combination of Carbonate Hydroxyapatite and Stem Cells from Human Deciduous Teeth Promotes Bone Regeneration by Enhancing BMP-2, VEGF and CD31 Expression in Immunodeficient Mice

The objective of this study was to clarify the efficiency of a combination of stem cells from human deciduous teeth and carbonate apatite in bone regeneration of calvarial defects. Immunodeficient mice (n = 5 for each group/4 groups) with artificial calvarial bone defects (5 mm in diameter) were developed, and stem cells from human deciduous teeth (SHEDs) and carbonate hydroxyapatite (CAP) granules were transplanted with an atelocollagen sponge as a scaffold. A 3D analysis using microcomputed tomography, and 12 weeks after transplantation, histological and immunohistochemical evaluations of markers of bone morphogenetic protein-2 (BMP-2), vascular endothelial growth factor (VEGF), and cluster of differentiation (CD) 31 were performed. In the 3D analysis, regenerated bone formation was observed in SHEDs and CAP, with the combination of SHEDs and CAP showing significantly greater bone regeneration than that in the other groups. Histological and immunohistochemical evaluations showed that combining SHEDs and CAP enhanced the expression of BMP-2, VEGF, and CD31, and promoted bone regeneration. This study demonstrates that the combination of SHEDs and CAP transplantation may be a promising tool for bone regeneration in alveolar defects.

Bone Using Stem Cells for Maxillofacial Bone Disorders: A Systematic Review and Meta-analysis

Due to economic, cultural, environmental, and social factors, the prevalence of maxillofacial bone disorders varies in different parts of the world. The present meta-analysis was conducted to assess the efficacy and safety of different type of stem cells-based scaffolds and their construction methods in maxillofacial bone disorders. We searched major indexing databases, including PubMed/Medline, ISI Web of Science, Scopus, Embase, and Cochrane Central without any language, study region, or type restrictions. A systematic search of articles published up to July 2021 was done. Of the 428 studies found through initial searches, 36 met the inclusion criteria. After applying the exclusion criteria, the main properties of 32 articles on 643 animals and 4 experimental studies on 52 patients (age range from 43 to 74 years) included in this meta-analysis. Our pooled analysis showed that stem cells-based scaffolds significantly improved the bone regeneration and formation in maxillofacial bone disorders (Prevalence: 0.54; 95% CI: 0.43, 0.64, P < 00001, I2 = 90 2). According to the results of these studies, in most studies, bone marrow-derived mesenchymal stem cells (BMSCs) have been used to regenerate bone, and these cells are still the gold standard in bone tissue engineering, a growth factor that is one of the three sides of the tissue engineering triangle. Bone morphogenetic proteins (BMP) especially BMP2 and platelet-rich plasma (PRP) are the most widely used growth factor and scaffold respectively. Platelet-rich plasma (PRP) is used as a scaffold and since it contains proteins, it also used as a growth factor and can be a stimulant of ossification. It seems that the future perspective of bone tissue engineering is to use the prototyping rapid method to build a composite and patient-specific scaffold from CT and MRI images, along with genetically modified stem cells.

Cytocompatibility and osteogenic differentiation of stem cells from human exfoliated deciduous teeth with cotton cellulose nanofibers for tissue engineering and regenerative medicine

Cellulose nanofibers (CNFs) are natural polymers with physical-chemical properties that make them very attractive for modulating stem cell differentiation, a crucial step in tissue engineering and regenerative medicine. Although cellulose is cytocompatible, when materials are in nanoscale, they become more reactive, needing to evaluate its potential toxic effect to ensure safe application. This study aimed to investigate the cytocompatibility of cotton CNF and its differentiation capacity induction on stem cells from human exfoliated deciduous teeth. First, the cotton CNF was characterized. Then, the cytocompatibility and the osteogenic differentiation induced by cotton CNF were examined. The results revealed that cotton CNFs have about 6-18 nm diameters, and the zeta potential was -10 mV. Despite gene expression alteration, the cotton CNF shows good cytocompatibility. The cotton CNF induced an increase in phosphatase alkaline activity and extracellular matrix mineralization. The results indicate that cotton CNF has good cytocompatibility and can promote cell differentiation without using chemical inducers, showing great potential as a new differentiation inductor for tissue engineering and regenerative medicine applications.

Multipotency and Immunomodulatory Benefits of Stem Cells From Human Exfoliated Deciduous Teeth

Stem cells derived from human exfoliated deciduous teeth (SHEDs) are considered a promising cell population for cell-based or cell-free therapy and tissue engineering because of their proliferative, multipotency and immunomodulator. Based on recent studies, we find that SHEDs show the superior ability of nerve regeneration in addition to the potential of osteogenesis, odontogenesis owing to their derivation from the neural crest. Besides, much evidence suggests that SHEDs have a paracrine effect and can function as immunomodulatory regents attributing to their capability of secreting cytokines and extracellular vesicles. Here, we review the characteristic of SHEDs, their multipotency to regenerate damaged tissues, specifically concentrating on bones or nerves, following the paracrine activity or immunomodulatory benefits of their potential for clinical application in regenerative medicine.

Gingival-Derived Mesenchymal Stem Cell from Rabbit (Oryctolagus cuniculus): Isolation, Culture, and Characterization

OBJECTIVE

 This study aims to confirm whether the GDMSCs isolated from rabbit's (Oryctolagus cuniculus) gingiva are mesenchymal stem cells (MSCs).

MATERIALS AND METHODS

 This study design was partly quasi-experimental with an observational design. GDMSCs were isolated from the gingiva of healthy male rabbits (O. cuniculus) (n = 2), 6 months old, and 3 to 5 kg of body weight. The specific cell surface markers of MSCs; clusters of differentiation (CD), namely, CD44, CD73, CD90, CD105, and CD200 expressions; and hematopoietic stem cell surface markers CD34 and CD45 were examined using flow cytometry and immunohistochemistry with immunofluorescence. The osteogenic differentiation of isolated GDMSCs was examined using alizarin red staining.

RESULTS

 GDMSCs in the fourth passage showed a spindle-like formation and fibroblast-like cells that attached to the base of the culture plate. GDMSCs were MSCs that positively expressed CD44, CD73, CD90, CD105, and CD200 but did not express CD34 and CD45 when examined using flow cytometry and immunohistochemical analysis. GDMSCs had osteogenic differentiation confirmed by calcified deposits in vitro with a red-violet and brownish color after alizarin red staining.

CONCLUSION

 GDMSCs isolated from the rabbits (O. cuniculus) were confirmed as MSCs in vitro documented using immunohistochemistry and flow cytometry. GDMSCs can differentiate into osteogenic lineage in vitro that may be suitable for regenerative dentistry.

Dental stem cells: The role of biomaterials and scaffolds in developing novel therapeutic strategies

Dental stem cells (DSCs) are self-renewable cells that can be obtained easily from dental tissues, and are a desirable source of autologous stem cells. The use of DSCs for stem cell transplantation therapeutic approaches is attractive due to their simple isolation, high plasticity, immunomodulatory properties, and multipotential abilities. Using appropriate scaffolds loaded with favorable biomolecules, such as growth factors, and cytokines, can improve the proliferation, differentiation, migration, and functional capacity of DSCs and can optimize the cellular morphology to build tissue constructs for specific purposes. An enormous variety of scaffolds have been used for tissue engineering with DSCs. Of these, the scaffolds that particularly mimic tissue-specific micromilieu and loaded with biomolecules favorably regulate angiogenesis, cell-matrix interactions, degradation of extracellular matrix, organized matrix formation, and the mineralization abilities of DSCs in both in vitro and in vivo conditions. DSCs represent a promising cell source for tissue engineering, especially for tooth, bone, and neural tissue restoration. The purpose of the present review is to summarize the current developments in the major scaffolding approaches as crucial guidelines for tissue engineering using DSCs and compare their effects in tissue and organ regeneration.