Oral Cavity as a Source of Mesenchymal Stem Cells Useful for Regenerative Medicine in Dentistry

The Protective Effects of MSC-Derived Exosomes Against Chemotherapy-Induced Parotid Gland Cytotoxicity

Background: Fluorouracil (5-FU) is one of the most popular chemotherapeutic agents used in various cancer therapy protocols. Cell-free therapy utilizing exosomes is gaining increased popularity as a safer option due to concerns over potential tumor progression following stem cell therapy. Methods: Parotid glands of albino were treated with a single bone marrow mesenchymal stem cell (BMMSC)-derived exosomes injection (100 μg/kg/dose suspended in 0.2 mL phosphate-buffered saline [PBS]), a single 5-Fu injection (20 mg/kg), and BMMSC-derived exosomes plus 5-FU and compared to control group (daily saline injections). After 30 days, the parotid glands were examined using qualitative histological evaluation, immunohistochemical evaluation using rabbit polyclonal mouse antibody to Ki-67, caspase 3, and iNOS, as well as quantitative real-time polymerase chain reaction (RT-PCR) to evaluate gene expression of TGFβ1, TNF-α, and BCL-2. Results: Histological examination of the parotid gland revealed that BMMSC-derived exosomes restored the glands' architecture and repaired most of the distortion created by 5-FU. Immunohistochemical expression of tumor proliferation and cell death markers were restored to normal levels in the exosome-treated groups that were similar to the control group. Furthermore, BMMSC-derived exosomes reversed the effects of 5-FU on quantitative gene expression levels and showed a significant decrease in TNF-α (p < 0.001) and a significant increase in TGFβ (p < 0.0001) and BCL-2 (p < 0.05) when compared to 5-FU treatment. Conclusion: Within the limitations of the current study, BMMSC-derived exosomes have the potential to counteract the cytotoxic effects of 5-FU on the parotid glands of rats in vivo. Further studies are deemed necessary to simulate clinical scenarios.

The role of mesenchymal stem cells-derived from oral and teeth in regenerative and reconstructive medicine

Defects and abnormalities of the skull, jaw, and face tissues due to various physiological problems such as speech, chewing, and swallowing disorders, cause illness and psychological effects with creation of significant public health challenges. Both autograft and allograft reconstruction methods, have different limitations, especially in the complete reconstruction of complex tissues such as sensory and periodontal tissues, which cannot be wholly relied on for treatment. Recently, mesenchymal stem cells (MSCs)-derived from oral and teeth have emerged as a promising alternative way in regenerative and reconstructive medicine. These types of stem cells with the high differentiation potential and self-renewal capabilities include dental pulp stem cells (DPSCs), stem cells from human exfoliated deciduous teeth (SHEDs), periodontal stem cells (PDLSCs) and gum-derived stem cells (GMSCs). These stem cells can be easily collected from accessible and numerous sources, such as extracted molars and milk teeth, with minimal invasiveness, playing pivotal roles in clinical application. This review explains the applications and therapeutic effects of the above-mentioned MSCs-derived from oral and dental tissues. Each of these stem cells, have unique characteristics and used for the treatment of specific abnormalities and defects. In this article, we aims to elucidate the indispensable and pivotal roles of MSCs-derived from the oral and teeth in addressing intractable and complex challenges in restorative and reconstructive medicine.

Dysregulation of lncRNA GATA3-AS1 is Involved in the Pathogenesis of Pulpitis by the Regulation of miR-17-3p

Purpose

When the pulp is inflamed or injured, cell morphology, gene expression, and synaptic connections change occur in the medullary dorsal horn, causing inflammation pain and formatting the pulpitis pain. To examine the impact of lncRNA GATA3-AS1 regulation of miR-17-3p on bioactivity and inflammation of lipopolysaccharides (LPS)-stimulated human dental pulp stem cells (hDPSCs).

Patients and Methods

The GATA3-AS1 expression in serum samples from patients with pulpitis, dental caries, and healthy control was examined using RT-qPCR. The GATA3-AS1 expression was verified using the GSE198359 dataset. hDPSCs were exposed to LPS to mimic in vitro pulpitis model. The viability and apoptotic rates of hDPSCs were determined by CCK-8 method and Flow cytometric analysis. The inflammatory cytokines levels were quantified using ELISA-based approach. A SOD assay kit was utilized to measure the activity of SOD. Bioinformatic analysis and dual-luciferase reporter assay were performed to explore the interaction between GATA3-AS1 and miR-17-3p, along with the potential mechanism.

Results

Serum and tissue GATA3-AS1 levels were elevated in patients with pulpitis. Silencing GATA3-AS1 overturned the LPS stimulation inhibited viability and promoted apoptosis, inflammation, and oxidative stress in hDPSCs. GATA3-AS1 could target miR-17-3p, and miR-17-3p downregulation reversed silencing GATA3-AS1-mediated effects in LPS-induced hDPSCs. The GATA3-AS1-miR-17-3p axis might mediate the progression of pulpitis by many potential pathways, such as the PI3K-Akt signaling pathway and MAPK signaling pathway.

Conclusion

GATA3-AS1 knockdown might have a protective effect on bioactivity, LPS-triggered inflammation, and damage in hDPSCs by regulating miR-17-3p, which might be a promising target for the treatment of pulpitis.

Spheroids from Epithelial and Mesenchymal Cell Phenotypes as Building Blocks in Bioprinting (Review)

Most tissues and organs are based on cells of the epithelial and mesenchymal phenotypes. Epithelial cells build protective barriers, have a key role in absorption and secretion, and participate in metabolism. Characterized by high plasticity and ability to migrate, mesenchymal cells ensure structural support, promote tissue restoration and are important for matrix remodeling. Interaction between these two cell types is critical for maintaining the body integrity and functioning. Modern tissue engineering is aimed at creation of artificial tissues and organs that have the required cellular composition, mechanical properties and functional potential for medical usage. One of the most popular methods of tissue engineering is 3D bioprinting, which allows creating complex three-dimensional structures with specified characteristics. Recently, special attention has been paid to bioprinting with spheroids being three-dimensional cellular aggregates that can be used as building blocks for tissue-engineered structures. Due to numerous cell-to-cell contacts and accumulation of extracellular matrix, spheroids ensure conditions allowing to form anatomical tissues and organs. To optimize bioprinting conditions, one shall precisely understand the mechanical properties of spheroids, as they directly affect the ability of cells to migrate and fuse, and thus the rate of construct formation and its overall morphology. This review summarizes the available data on the differences in mechanical properties of epithelial and mesenchymal spheroids, examines methods for their co-culturing in various applications of regenerative medicine, as well as analyzes the peculiarities of their use in different bioprinting methods to obtain high-quality tissue constructs.

Versatile hydrogels prepared by microfluidics technology for bone tissue engineering applications

Bone defects are a prevalent issue resulting from various factors, such as trauma, degenerative diseases, congenital disabilities, and the surgical removal of tumors. Current methods for bone regeneration have limitations. In this context, the fusion of tissue engineering and microfluidics has emerged as a promising strategy in the field of bone regeneration. This study describes the classification of microfluidic devices based on the nature of flow and channel type, as well as the materials and techniques required. An overview of microfluidic methods used to prepare hydrogels and the advantages of using these hydrogels in bone tissue engineering (BTE) combining several basic elements of BTE to highlight its advantages is provided. Furthermore, this work emphasizes the benefits of using hydrogels prepared via microfluidics over conventional hydrogels in BTE because of their controlled release of cargo, they can be used for in situ injection, simplify the steps of single-cell encapsulation and have the advantages of high-throughput and precise preparation. Additionally, organ-on-a-chip models fabricated via microfluidics offer a platform for studying cell and tissue behaviors in an authentic and dynamic environment. Moreover, microfluidic devices can be utilized for noninvasive diagnosis and therapy. Finally, this paper summarizes the preclinical and clinical applications of hydrogels prepared via microfluidics for bone regeneration by focusing on their current developmental status, limitations associated with their application, and future challenges, which underscore their potential impacts on advancing regenerative medicine practices.

Suppressing the Aging Phenotype of Mesenchymal Stromal Cells: Are We Ready for Clinical Translation?

Mesenchymal stem/stromal cells (MSCs) are involved in the maintenance and regeneration of a large variety of tissues due to their stemness and multi-lineage differentiation capability. Harnessing these advantageous features, a flurry of clinical trials have focused on MSCs to treat different pathologies, but only few protocols have received regulatory approval so far. Among the various causes hindering MSCs' efficacy is the emergence of cellular senescence, which has been correlated with specific characteristics, such as morphological and epigenetic alterations, DNA damage, ROS production, mitochondrial dysfunction, telomere shortening, non-coding RNAs, loss of proteostasis, and a peculiar senescence-associated secretory phenotype. Several strategies have been investigated for delaying or even hopefully reverting the onset of senescence, as assessed by the senescent phenotype of MSCs. Here, the authors reviewed the most updated literature on the potential causes of senescence, with a particular emphasis on the current and future therapeutic approaches aimed at reverting senescence and/or extending the functional lifespan of stem cells.

FoxO1-Overexpressed Small Extracellular Vesicles Derived from hPDLSCs Promote Periodontal Tissue Regeneration by Reducing Mitochondrial Dysfunction to Regulate Osteogenesis and Inflammation

Purpose

Periodontitis is a chronic infectious disease characterized by progressive inflammation and alveolar bone loss. Forkhead box O1 (FoxO1), an important regulator, plays a crucial role in maintaining bone homeostasis and regulating macrophage energy metabolism and osteogenic differentiation of mesenchymal stem cells (MSCs). In this study, FoxO1 was overexpressed into small extracellular vesicles (sEV) using engineering technology, and effects of FoxO1-overexpressed sEV on periodontal tissue regeneration as well as the underlying mechanisms were investigated.

Methods

Human periodontal ligament stem cell (hPDLSCs)-derived sEV (hPDLSCs-sEV) were isolated using ultracentrifugation. They were then characterized using transmission electron microscopy, Nanosight, and Western blotting analyses. hPDLSCs were treated with hPDLSCs-sEV in vitro after stimulation with lipopolysaccharide, and osteogenesis was evaluated. The effect of hPDLSCs-sEV on the polarization phenotype of THP-1 macrophages was also evaluated. In addition, we measured the reactive oxygen species (ROS) levels, adenosine triphosphate (ATP) production, mitochondrial characteristics, and metabolism of hPDLSCs and THP-1 cells. Experimental periodontitis was established in vivo in mice. HPDLSCs-sEV or phosphate-buffered saline (PBS) were injected into periodontal tissues for four weeks, and the maxillae were collected and assessed by micro-computed tomography, histological staining, and small animal in vivo imaging.

Results

In vitro, FoxO1-overexpressed sEV promoted osteogenic differentiation of hPDLSCs in the inflammatory environment and polarized THP-1 cells from the M1 phenotype to the M2 phenotype. Furthermore, FoxO1-overexpressed sEV regulated the ROS level, ATP production, mitochondrial characteristics, and metabolism of hPDLSCs and THP-1 cells in the inflammatory environment. In the in vivo analyses, FoxO1-overexpressed sEV effectively promoted bone formation and inhibited inflammation.

Conclusion

FoxO1-overexpressed sEV can regulate osteogenesis and immunomodulation. The ability of FoxO1-overexpressed sEV to regulate inflammation and osteogenesis can pave the way for the establishment of a therapeutic approach for periodontitis.

Stem cells in regenerative dentistry: Current understanding and future directions

BACKGROUND

Regenerative dentistry aims to enhance the structure and function of oral tissues and organs. Modern tissue engineering harnesses cell and gene-based therapies to advance traditional treatment approaches. Studies have demonstrated the potential of mesenchymal stem cells (MSCs) in regenerative dentistry, with some progressing to clinical trials. This review comprehensively examines animal studies that have utilized MSCs for various therapeutic applications. Additionally, it seeks to bridge the gap between related findings and the practical implementation of MSC therapies, offering insights into the challenges and translational aspects involved in transitioning from preclinical research to clinical applications.

HIGHLIGHTS

To achieve this objective, we have focused on the protocols and achievements related to pulp-dentin, alveolar bone, and periodontal regeneration using dental-derived MSCs in both animal and clinical studies. Various types of MSCs, including dental-derived cells, bone-marrow stem cells, and umbilical cord stem cells, have been employed in root canals, periodontal defects, socket preservation, and sinus lift procedures. Results of such include significant hard tissue reconstruction, functional pulp regeneration, root elongation, periodontal ligament formation, and cementum deposition. However, cell-based treatments for tooth and periodontium regeneration are still in early stages. The increasing demand for stem cell therapies in personalized medicine underscores the need for scientists and responsible organizations to develop standardized treatment protocols that adhere to good manufacturing practices, ensuring high reproducibility, safety, and cost-efficiency.

CONCLUSION

Cell therapy in regenerative dentistry represents a growing industry with substantial benefits and unique challenges as it strives to establish sustainable, long-term, and effective oral tissue regeneration solutions.

Efficacy of a Solution Containing 33% Trichloroacetic Acid and Hydrogen Peroxide in Decontaminating Machined vs. Sand-Blasted Acid-Etched Titanium Surfaces

This in vitro study assessed the efficacy of a solution containing 33% trichloroacetic acid (CCl3COOH; TCA) and hydrogen peroxide (H2O2) in decontaminating machined (MAC) and sand-blasted acid-etched (SBAE) titanium surfaces. A total of 80 titanium disks were prepared (40 MAC and 40 SBAE). Streptococcus sanguinis and Enterococcus faecalis strains were incubated on 36 samples, while the remaining 44 were kept as controls. Roughness analysis and scanning electron microscopy were used to evaluate the surface features before and after TCAH2O2 treatment. The viability of human adipose-derived mesenchymal stem cells (ASCs) after TCAH2O2 decontamination was assessed with a chemiluminescent assay along with cell morphology through fluorescent staining. TCAH2O2 preserved the surface topography of MAC and SBAE specimens. It also effectively eradicated bacteria on both types of specimens without altering the surface roughness (p > 0.05). Also, no significant differences in protein adsorption between the pristine and TCAH2O2-treated surfaces were found (p = 0.71 and p = 0.94). While ASC proliferation remained unchanged on MAC surfaces, a decrease was observed on the decontaminated SBAE specimens at 24 and 48 h (p < 0.05), with no difference at 72 h (p > 0.05). Cell morphology showed no significant changes after 72 h on both surface types even after decontamination. This study suggests TCAH2O2 as a promising decontamination agent for titanium surfaces, with potential implications for peri-implant health and treatment outcomes.

Photobiomodulation Effects on Periodontal Ligament Stem Cells: A Systematic Review of In Vitro Studies

BACKGROUND

Stem cell therapy has been considered to play a paramount role in the treatment modalities available for regenerative dentistry. The established beneficial effects of photobiomodulation (PBM) at the cellular level have led to the combined use of these two factors (PBM and stem cells). The main goal of this study was firstly to critically appraise the effects of PBM on periodontal ligament stem cells (PDLSCs), and secondly to explore the most effective PBM protocols applied.

METHODS

Pubmed, Cochrane, Scopus, Science Direct, and Google Scholar search engines were used to identify experimental in vitro studies in which PBM was applied to cultured PDLSCs. After applying specific keywords, additional filters, and inclusion/exclusion criteria, a preliminary number of 245 articles were narrowed down to 11 in which lasers and LEDs were used within the 630 - 1064 nm wavelength range. Selected articles were further assessed by three independent reviewers for strict compliance with PRISMA guidelines, and a modified Cochrane risk of bias to determine eligibility.

STATISTICAL ANALYSIS

The dataset analysed was extracted from the studies with sufficient and clearly presented PBM protocols. Simple univariate regression analysis was performed to explore the significance of contributions of potential quantitative predictor variables toward study outcomes, and a one-way ANOVA model was employed for testing differences between the laser or LED sources of the treatments. The significance level for testing was set at α = 0.05.

RESULTS

The proliferation rate, osteogenic differentiation, and expression of different indicative genes for osteogenesis and inflammation suppression were found to be positively affected by the application of various types of lasers and LEDs. With regard to the PBM protocol, only the wavelength variable appeared to affect the treatment outcome; indeed, the 940 nm wavelength parameter was found not to exert a favourable effect.

CONCLUSIONS

Photobiomodulation can enhance the stemness and differentiation capacities of periodontal ligament stem cells. Therefore, for PBM protocols, there remains no consensus amongst the scientific community. Statistical analyses performed here indicated that the employment of a near-infrared (NIR) wavelength of 940 nm may not yield a significant favourable outcome, although those within the 630 - 830 nm range did so. Concerning the fluence, it should not exceed 8 J/cm2 when therapy is applied by LED devices, and 4 J/cm2 when applied by lasers, respectively.

Advances in oral mesenchymal stem cell-derived extracellular vesicles in health and disease

Extracellular vesicles (EVs) are nano-size vesicles secreted naturally by all cells into the extracellular space and have been recognized as important cell-cell mediators in multicellular organisms. EVs contain nucleic acids, proteins, lipids, and other cellular components, regulating many basic biological processes and playing an important role in regenerative medicine and diseases. EVs can be traced to their cells of origin and exhibit a similar function. Moreover, EVs demonstrate low immunogenicity, good biocompatibility, and fewer side effects, compared to their parent cells. Mesenchymal stem cells (MSCs) are one of the most important resource cells for EVs, with a great capacity for self-renewal and multipotent differentiation, and play an essential role in stem cell therapy. The mechanism of MSC therapy was thought to be attributed to the differentiation of MSCs after targeted migration, as previously noted. However, emerging evidence shows the previously unknown role of MSC-derived paracrine factors in stem cell therapy. Especially EVs derived from oral tissue MSCs (OMSC-EVs), show more advantages than those of all other MSCs in tissue repair and regeneration, due to their lower invasiveness and easier accessibility for sample collection. Here, we systematically review the biogenesis and biological characteristics of OMSC-EVs, as well as the role of OMSC-EVs in intercellular communication. Furthermore, we discuss the potential therapeutic roles of OMSC-EVs in oral and systemic diseases. We highlight the current challenges and future directions of OMSC-EVs to focus more attention on clinical translation. We aim to provide valuable insights for the explorative clinical application of OMSC-EVs.

Gingival mesenchymal stem cell therapy, immune cells, and immunoinflammatory application

MSC-based therapeutic strategies have proven to be incredibly effective. Robust self-renewal, multilineage differentiation, and potential for tissue regeneration and disease treatments are all features of MSCs isolated from oral tissue. Human exfoliated deciduous teeth, dental follicles, dental pulp, apical papilla SCs, and alveolar bone are the primary sources of oral MSC production. The early immunoinflammatory response is the first stage of the healing process. Oral MSCs can interact with various cells, such as immune cells, revealing potential immunomodulatory regulators. They also have strong differentiation and regeneration potential. Therefore, a ground-breaking strategy would be to research novel immunomodulatory approaches for treating disease and tissue regeneration that depend on the immunomodulatory activities of oral MSCs during tissue regeneration.

Chitin scaffolds derived from the marine demosponge Aplysina fistularis stimulate the differentiation of dental pulp stem cells

The use of stem cells for tissue regeneration is a prominent trend in regenerative medicine and tissue engineering. In particular, dental pulp stem cells (DPSCs) have garnered considerable attention. When exposed to specific conditions, DPSCs have the ability to differentiate into osteoblasts and odontoblasts. Scaffolds are critical for cell differentiation because they replicate the 3D microenvironment of the niche and enhance cell adhesion, migration, and differentiation. The purpose of this study is to present the biological responses of human DPSCs to a purified 3D chitin scaffold derived from the marine demosponge Aplysina fistularis and modified with hydroxyapatite (HAp). Responses examined included proliferation, adhesion, and differentiation. The control culture consisted of the human osteoblast cell line, hFOB 1.19. Electron microscopy was used to examine the ultrastructure of the cells (transmission electron microscopy) and the surface of the scaffold (scanning electron microscopy). Cell adhesion to the scaffolds was determined by neutral red and crystal violet staining methods. An alkaline phosphatase (ALP) assay was used for assessing osteoblast/odontoblast differentiation. We evaluated the expression of osteogenic marker genes by performing ddPCR for ALP, RUNX2, and SPP1 mRNA expression levels. The results show that the chitin biomaterial provides a favorable environment for DPSC and hFOB 1.19 cell adhesion and supports both cell proliferation and differentiation. The chitin scaffold, especially with HAp modification, isolated from A. fistularis can make a significant contribution to tissue engineering and regenerative medicine.

Gene-Activated Materials in Regenerative Dentistry: Narrative Review of Technology and Study Results

Treatment of a wide variety of defects in the oral and maxillofacial regions requires the use of innovative approaches to achieve best outcomes. One of the promising directions is the use of gene-activated materials (GAMs) that represent a combination of tissue engineering and gene therapy. This approach implies that biocompatible materials will be enriched with gene-carrying vectors and implanted into the defect site resulting in transfection of the recipient's cells and secretion of encoded therapeutic protein in situ. GAMs may be presented in various designs depending on the type of material, encoded protein, vector, and way of connecting the vector and the material. Thus, it is possible to choose the most suitable GAM design for the treatment of a particular pathology. The use of plasmids for delivery of therapeutic genes is of particular interest. In the present review, we aimed to delineate the principle of work and various designs of plasmid-based GAMs and to highlight results of experimental and clinical studies devoted to the treatment of periodontitis, jaw bone defects, teeth avulsion, and other pathologies in the oral and maxillofacial regions.

Therapeutic Potential of Oral-Derived Mesenchymal Stem Cells in Retinal Repair

The retina has restricted regeneration ability to recover injured cell layer because of reduced production of neurotrophic factors and increased inhibitory molecules against axon regrowth. A diseased retina could be regenerated by repopulating the damaged tissue with functional cell sources like mesenchymal stem cells (MSCs). The cells are able to release neurotrophic factors (NFs) to boost axonal regeneration and cell maintenance. In the current study, we comprehensively explore the potential of various types of stem cells (SCs) from oral cavity as promising therapeutic options in retinal regeneration. The oral MSCs derived from cranial neural crest cells (CNCCs) which explains their broad neural differentiation potential and secret rich NFs. They are comprised of dental pulp SCs (DPSCs), SCs from exfoliated deciduous teeth (SHED), SCs from apical papilla (SCAP), periodontal ligament-derived SCs (PDLSCs), gingival MSCs (GMSCs), and dental follicle SCs (DFSCs). The Oral MSCs are becoming a promising source of cells for cell-free or cell-based therapeutic approach to recover degenerated retinal. These cells have various mechanisms of action in retinal regeneration including cell replacement and the paracrine effect. It was demonstrated that they have more neuroprotective and neurotrophic effects on retinal cells than immediate replacement of injured cells in retina. This could be the reason that their therapeutic effects would be weakened over time. It can be concluded that neuronal and retinal regeneration through these cells is most likely due to their NFs that dramatically suppress oxidative stress, inflammation, and apoptosis. Although, oral MSCs are attractive therapeutic options for retinal injuries, more preclinical and clinical investigations are required.

Pulp-Dentin Complex Regeneration with Cell Transplantation Technique Using Stem Cells Derived from Human Deciduous Teeth: Histological and Immunohistochemical Study in Immunosuppressed Rats

The aim of this study was to histologically verify the performance of pulp-derived stem cells used in the pulp-dentin complex regeneration. Maxillary molars of 12 immunosuppressed rats were divided into two groups: the SC (stem cells) group, and the PBS (just standard phosphate-buffered saline) group. After pulpectomy and canal preparation, the teeth received the designated materials, and the cavities were sealed. After 12 weeks, the animals were euthanized, and the specimens underwent histological processing and qualitative evaluation of intracanal connective tissue, odontoblast-like cells, intracanal mineralized tissue, and periapical inflammatory infiltrate. Immunohistochemical evaluation was performed to detect dentin matrix protein 1 (DMP1). In the PBS group, an amorphous substance and remnants of mineralized tissue were observed throughout the canal, and abundant inflammatory cells were observed in the periapical region. In the SC group, an amorphous substance and remnants of mineralized tissue were observed throughout the canal; odontoblasts-like cells immunopositive for DMP1 and mineral plug were observed in the apical region of the canal; and a mild inflammatory infiltrate, intense vascularization, and neoformation of organized connective tissue were observed in the periapical region. In conclusion, the transplantation of human pulp stem cells promoted partial pulp tissue neoformation in adult rat molars.

Potential of Oral Cavity Stem Cells for Bone Regeneration: A Scoping Review

Bone loss is a common problem that ranges from small defects to large defects after trauma, surgery, or congenital malformations. The oral cavity is a rich source of mesenchymal stromal cells (MSCs). Researchers have documented their isolation and studied their osteogenic potential. Therefore, the objective of this review was to analyze and compare the potential of MSCs from the oral cavity for use in bone regeneration.

METHODS

A scoping review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. The databases reviewed were PubMed, SCOPUS, Scientific Electronic Library Online (SciELO), and Web of Science. Studies using stem cells from the oral cavity to promote bone regeneration were included.

RESULTS

A total of 726 studies were found, of which 27 were selected. The MSCs used to repair bone defects were (I) dental pulp stem cells of permanent teeth, (II) stem cells derived from inflamed dental pulp, (III) stem cells from exfoliated deciduous teeth, (IV) periodontal ligament stem cells, (V) cultured autogenous periosteal cells, (VI) buccal fat pad-derived cells, and (VII) autologous bone-derived mesenchymal stem cells. Stem cells associate with scaffolds to facilitate insertion into the bone defect and to enhance bone regeneration. The biological risk and morbidity of the MSC-grafted site were minimal. Successful bone formation after MSC grafting has been shown for small defects with stem cells from the periodontal ligament and dental pulp as well as larger defects with stem cells from the periosteum, bone, and buccal fat pad.

CONCLUSIONS

Stem cells of maxillofacial origin are a promising alternative to treat small and large craniofacial bone defects; however, an additional scaffold complement is required for stem cell delivery.

Transdifferentiation of periodontal ligament stem cells into acinar cells using an indirect co-culture system

Serous Acinar Cells (ACs) are mature and functional secretory epithelial cells that develop and complete through other stem cells at the end of the ductal system. So, the regeneration of the salivary gland damaged by radiation does not occur without cell therapy. Todays, an accessible tissue like the Periodontal Ligament (PDL) of the tooth was considered to easily extract the Mesenchymal Stem Cells (MSCs). In-vitro differentiation of stem cells before transplantation to damaged tissue reduces the risk of tumorigenesis. This study was conducted to evaluate the feasibility of differentiation of PDLSCs into salivary acinar cells by a co-culture system. PDLSCs were isolated from adult human PDL tissue and co-cultured with rat parotid ACs using an indirect co-culture system. The transdifferentiation of PDLSCs was evaluated by PCR of Aquaporin 5 (AQP5) and Carbonic anhydrase 6 (CA6) genes, then quantitative real-time PCR was used to measure the gene expression levels. The data were analyzed by ANOVA. Specific bond with the correct size on 6% acrylamide gel and TBE5X buffer showed the expression of AQP5 and CA6 in PDLSCs co-cultured with acinar cells. RT-PCR revealed co-cultured PDLSCs with or without KGF (Keratinocyte Growth Factor) showed significantly increased expression of AQP5 genes in compared to the initial PDLSCs. Expression of AQP5 and CA6, indicating successful transdifferentiation of PDLSCs into ACs, in co-culture system for 3 weeks.

Assessment of angiogenic potential of mesenchymal stem cells derived conditioned medium from various oral sources

Background

Abnormal angiogenesis hamper blood vessel proliferation implicated in various biological processes. The current method available to clinically treat patients to enhance angiogenesis is administering the angiogenic growth factors. However, due to a lack of spatiotemporal control over the substantial release of these factors, numerous drawbacks are faced such as leaky vasculature. Hence, stem-cell-based therapeutic applications are running their race to evolve as potential targets for deranged angiogenesis. In clinical dentistry, adequate tissue vascularization is essential for successful endodontic therapies such as apexogenesis and apexification. Furthermore, wound healing of the extraction socket and tissue regeneration post-surgical phase of treatment including implant placement require angiogenesis as a foundation for the ultimate success of treatment. Mesenchymal stem cells (MSCs) secrete certain growth factors and cytokines in the culture medium during the proliferation. These factors and cytokines are responsible for various biological activities inside human body. Oral cavity-derived stem cells can secrete growth factors that enhance angiogenesis.

Aim

The aim of the study was to investigate the angiogenic potential of conditioned medium (CM) of MSCs derived from different oral sources.

Methods

Oral tissues such as dental pulp of adult and deciduous teeth, gingiva, and buccal fat were used to isolate dental pulp MSCs (DPSCs), exfoliated deciduous teeth, gingival MSCs, and buccal fat derived MSCs. MSCs conditioned medium (CM) from passage four cells from all the sources were obtained at 48 h interval and growth factor analysis was performed using flow cytometry. To assess the functionality of the CM, Chick Yolk Sac Membrane (YSM) assay was performed.

Results

CM obtained from DPSCs showed higher levels of vascular endothelial growth factor, fibroblast growth factor, and hepatocyte growth factor as evidenced by flow cytometry. Furthermore, DPSC-CM exhibited significantly higher pro-angiogenic potential when assessed in in-ovo YSM assay.

Conclusion

DPSCs so far seems to be the best source as compare to the rest of oral sources in promoting angiogenesis. A novel source of CM derived from buccal fat stem cells was used to assess angiogenic potential. Thus, the present study shows that CM derived from oral cavity-derived-MSCs has a dynamic and influential role in angiogenesis.

Relevance for Patients

CM derived from various oral sources of MSCs could be used along with existing therapies in medical practice where patients have compromised blood supply like in diabetes and in patients with debilitating disorders. In clinical dentistry, adequate tissue vascularization is essential for successful wound healing, grafting procedures, and endodontic therapies. DPSCs-CM shows better angiogenic potential in comparison with other oral sources of MSCs-CM. Our findings could be a turning point in the management of all surgical and regenerative procedures requiring increased angiogenesis.

Endothelial Cells Promote Osteogenesis by Establishing a Functional and Metabolic Coupling With Human Mesenchymal Stem Cells

Bone formation involves a complex crosstalk between endothelial cells (EC) and osteodifferentiating stem cells. This functional interplay is greatly mediated by the paracrine and autocrine action of soluble factors released at the vasculature-bone interface. This study elucidates the molecular and functional responses triggered by this intimate interaction. In this study, we showed that human dermal microvascular endothelial cells (HMEC) induced the expression of pro-angiogenic factors in stem cells from human exfoliated deciduous teeth (SHED) and sustain their osteo-differentiation at the same time. In contrast, osteodifferentiating SHED increased EC recruitment and promoted the formation of complex vascular networks. Moreover, HMEC enhanced anaerobic glycolysis in proliferating SHED without compromising their ability to undergo the oxidative metabolic shift required for adequate osteo-differentiation. Taken together, these findings provide novel insights into the molecular mechanism underlying the synergistic cooperation between EC and stem cells during bone tissue renewal.

Clinical, Histological, and Scintigraphic Comparative Study of the Use of Mandibular Bone Marrow and Peripheral Blood in Bone Neoformation

Materials and Methods

The study included 16 patients with maxillary atresia. The region was grafted with xenograft blocks associated with the following treatments: G1, the patient's peripheral blood during surgery, and G2, dripping of mandibular bone marrow blood until the xenograft was completely wet. After 7 and 14 days, scintigraphic images of the regions of interest (ROI) were taken to quantify pixels, which indicate osteogenic activity. Additionally, trephined samples obtained at the time of implant placement were stained in H&E, and newly formed bone tissue was quantified. The data were tabulated and statistically analyzed at a significance level of 5%.

Results

Scintigraphic data showed greater osteogenic activity with mandibular bone marrow blood (G2) at all times evaluated (p < 0.05). As for the histomorphometric analysis, a greater amount of bone tissue was observed in samples treated with mandibular bone marrow blood (G2) compared to peripheral blood (G1) (p < 0.05).

Conclusions

The appositional bone reconstruction technique in the block associated with mandibular bone marrow blood increased bone neoformation and osteogenic activity compared to conventional graft treatment with peripheral blood.