Use of buccal fat pad-derived stem cells cultured on bioceramics for repair of critical-sized mandibular defects in healthy and osteoporotic rats

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.

Comparative Evaluation of the Functional Potential of Mesenchymal Stem Cells from the Bichat's Fat Pad, Bone Marrow, and Adipose Tissue for Bone Tissue Regeneration

The functional potential of mesenchymal stem cells (MSC) isolated from Bichat's fat pad for osteoinduction in dentistry was compared with that of MSC from the adipose tissue and bone marrow. Functional activity of MSC was evaluated by the rate of their proliferation, migration, and differentiation into osteoblasts under the influence of erythropoietin. MSC from the Bichat's fat pad have higher proliferative activity than MSC from the adipose tissue or bone marrow under the influence of platelet-enriched plasma. Moreover, they are characterized by low migration activity, differentiate into osteoblasts, and intensively produce alkaline phosphatase under the influence of erythropoietin. The revealed functional potential of MSC from the Bichat's fat pad makes them promising for cell therapy, including osteoinduction in dentistry.

Bone Regeneration with Dental Pulp Stem Cells in an Experimental Model

BACKGROUND/OBJECTIVES

The therapeutic approach to bone mass loss and bone's limited self-regeneration is a major focus of research, emphasizing new biomaterials and cell therapy. Tissue bioengineering emerges as a potential alternative to conventional treatments. In this study, an experimental model of a critical bone lesion in rats was used to investigate bone regeneration by treating the defect with biomaterials Evolution® and Gen-Os® (OsteoBiol®, Turín, Italy), with or without mesenchymal stromal cells from dental pulp (DP-MSCs).

METHODS

Forty-six adult male Wistar rats were subjected to a 5-mm critical bone defect in the right mandible, which does not regenerate without intervention. The rats were randomly assigned to a Simulated Group, Control Group, or two Study Groups (using Evolution®, Gen-Os®, and DP-MSCs). The specimens were euthanized at three or six months, and radiological, histological, and ELISA tests were conducted to assess bone regeneration.

RESULTS

The radiological results showed that the DP-MSC group achieved uniform radiopacity and continuity in the bone edge, with near-complete structural defect restitution. Histologically, full bone regeneration was observed, with well-organized, vascularized lamellar bone and no lesion edges. These findings were supported by increases in endoglin, transforming growth factor-beta 1 (TGF-β1), protocollagen, parathormone, and calcitonin, indicating a conducive environment for bone regeneration.

CONCLUSIONS

The use of DP-MSCs combined with biomaterials with appropriate three-dimensional matrices is a promising therapeutic option for further exploration.

The Buccal Fat Pad: A Unique Human Anatomical Structure and Rich and Easily Accessible Source of Mesenchymal Stem Cells for Tissue Repair

Buccal fat pads are biconvex adipose tissue bags that are uniquely found on both sides of the human face along the anterior border of the masseter muscles. Buccal fat pads are important determinants of facial appearance, facilitating gliding movements of facial masticatory and mimetic muscles. Buccal fad pad flaps are used for the repair of oral defects and as a rich and easily accessible source of mesenchymal stem cells. Here, we introduce the buccal fat pad anatomy and morphology and report its functions and applications for oral reconstructive surgery and for harvesting mesenchymal stem cells for clinical use. Future frontiers of buccal fat pad research are discussed. It is concluded that many biological and molecular aspects still need to be elucidated for the optimal application of buccal fat pad tissue in regenerative medicine.

3D bioprinted small extracellular vesicles from periodontal cells enhance mesenchymal stromal cell function

Recent research indicates that combining 3D bioprinting and small extracellular vesicles (sEVs) offers a promising 'cell-free' regenerative medicine approach for various tissue engineering applications. Nonetheless, the majority of existing research has focused on bioprinting of sEVs sourced from cell lines. There remains a notable gap in research regarding the bioprinting of sEVs derived from primary human periodontal cells and their potential impact on ligamentous and osteogenic differentiation. Here, we investigated the effect of 3D bioprinted periodontal cell sEVs constructs on the differentiation potential of human buccal fat pad-derived mesenchymal stromal cells (hBFP-MSCs). Periodontal cell-derived sEVs were enriched by size exclusion chromatography (SEC) with particle-shaped morphology, and characterized by being smaller than 200 nm in size and CD9/CD63/CD81 positive, from primary human periodontal ligament cells (hPDLCs) and human gingival fibroblasts (hGFs). The sEVs were then 3D bioprinted in 10 % gelatin methacryloyl (GelMA) via microextrusion bioprinting. Release of sEVs from bioprinted constructs was determined by DiO-labelling and confocal imaging, and CD9 ELISA. Attachment and ligament/osteogenic/cementogenic differentiation of hBFP-MSCs was assessed on bioprinted GelMA, without and with sEVs (GelMA/hPDLCs-sEVs and GelMA/hGFs-sEVs), scaffolds. hBFP-MSCs seeded on the bioprinted sEVs constructs spread well with significantly enhanced focal adhesion, mechanotransduction associated gene expression, and ligament and osteogenesis/cementogenesis differentiation markers in GelMA/hPDLCs-sEVs, compared to GelMA/hGFs-sEVs and GelMA groups. A 2-week osteogenic and ligamentous differentiation showed enhanced ALP staining, calcium formation and toluidine blue stained cells in hBFP-MSCs on bioprinted GelMA/hPDLCs-sEVs constructs compared to the other two groups. The proof-of-concept data from this study supports the notion that 3D bioprinted GelMA/hPDLCs-sEVs scaffolds promote cell attachment, as well as ligamentous, osteogenic and cementogenic differentiation, of hBFP-MSCs in vitro.

Effect of buccal fat autotransplantation on improving the alveolar socket bone regeneration: An in-vivo study

Background

There are various materials used for socket preservation following dental extraction. The aim of the present animal study was to histologically investigate the efficacy of buccal fat autotransplantation on alveolar bone regeneration following dental extraction.

Study design

In this prospective, double-blind laboratory experiment with a split-mouth design, 16 mandibular second premolar teeth in eight beagle dogs were extracted, and half of the extraction sockets were randomly filled using buccal fat autotransplantation. Other samples were left untouched to heal normally by the formed blood clot. Buccal fat autotransplantation was the primary predictor variable, and the type and amount of newly formed bone were the primary outcome variables. Assessment methods were the H & E coloring technique and histomorphometric evaluation. The significance level was set at 0.05, and data was subjected to Chi-Square and Wilcoxon signed-rank tests using SAS statistical software version 9.4.

Results

From the total number of 16 samples in 8 dogs, 50% of the samples in the intervention group represented inflammation with lower intensity compared to 33% in the control group; however, this difference was not considered statistically significant (Chi-Square test, P-value = 0.55). Wilcoxon test results showed no statistically significant difference between the two groups regarding the mean amount of total bone formation (Z = 0.00, P-value = 1.00).

Conclusion

It was inferred from the outcomes of the present study that when compared to the normal healing of the socket, buccal fat autotransplantation did not represent with superior outcome concerning the socket bone regeneration.

Effects of Oral Cavity Stem Cell Sources and Serum-Free Cell Culture on Hydrogel Encapsulation of Mesenchymal Stem Cells for Bone Regeneration: An In Vitro Investigation

INTRODUCTION

To develop a stem cell delivery model and improve the safety of stem cell transplantation for bone regeneration, this study aimed to determine the effects of stem cell sources, serum-free cell culture, and hydrogel cell encapsulation on the growth and osteogenic differentiation of mesenchymal stem cells (MSCs) from the oral cavity.

METHODS

The study groups were categorized according to stem cell sources into buccal fat pad adipose (hBFP-ADSCs) (Groups 1, 4, and 7), periodontal ligament (hPDLSCs) (Groups 2, 5, and 8), and dental pulp-derived stem cells (hDPSCs) (Groups 3, 6, and 9). MSCs from each source were isolated and expanded in three types of sera: fetal bovine serum (FBS) (Groups 1-3), human serum (HS) (Groups 4-6), and synthetic serum (SS) (StemPro™ MSC SFM) (Groups 7-9) for monolayer (m) and hydrogel cell encapsulation cultures (e). Following this, the morphology, expression of MSC cell surface antigens, growth, and osteogenic differentiation potential of the MSCs, and the expression of adhesion molecules were analyzed and compared.

RESULTS

SS decreased variations in the morphology and expression levels of cell surface antigens of MSCs from three cell sources (Groups 7m-9m). The levels of osteoblastic differentiation of the hPDLSCs and hBFP-ADSCs were increased in SS (Groups 8m and 7m) and the cell encapsulation model (Groups 1e, 4e, 7e-9e), but the promoting effects of SS were decreased in a cell encapsulation model (Groups 7e-9e). The expression levels of the alpha v beta 3 (ITG-αVβ3) and beta 1 (ITG-β1) integrins in the encapsulated cells in FBS (Group 1e) were higher than those in the SS (Group 7e).

CONCLUSIONS

Human PDLSCs and BFP-ADSCs were the optimum stem cell source for stem cell encapsulation by using nanohydroxyapatite-calcium carbonate microcapsule-chitosan/collagen hydrogel in serum-free conditions.

Effects of periodontal cells-derived extracellular vesicles on mesenchymal stromal cell function

OBJECTIVE

To enrich and compare three extracellular vesicles-EV subtypes (apoptotic bodies, microvesicles and small EV) from three periodontal cells (periodontal ligament cells-PDLCs, alveolar bone-derived osteoblasts-OBs and gingival fibroblasts-GFs), and assess uptake and cell function changes in buccal fat pad-derived mesenchymal stromal cells (BFP-MSCs).

BACKGROUND

Periodontal cells such as PDLCs, OBs and GFs have the potential to enhance bone and periodontal regeneration, but face significant challenges, such as the regulatory and cost implications of in vitro cell culture and storage. To address these challenges, it is important to explore alternative 'cell-free' strategies, such as extracellular vesicles which have emerged as promising tools in regenerative medicine, to facilitate osteogenic differentiation and bone regeneration.

METHODS AND MATERIALS

Serial centrifuges at 2600 and 16 000 g were used to isolate apoptotic bodies and microvesicles respectively. Small EV-sEV was enriched by our in-house size exclusion chromatography (SEC). The cellular uptake, proliferation, migration and osteogenic/adipogenic differentiation genes were analysed after EVs uptake in BFP-MSCs.

RESULTS

Three EV subtypes were enriched and characterised by morphology, particle size and EV-associated protein expression-CD9. Cellular uptake of the three EVs subtypes was observed in BFP-MSCs for up to 7 days. sEV from the three periodontal cells promoted proliferation, migration and osteogenic gene expression. hOBs-sEV showed superior levels of osteogenesis markers compared to that hPDLCs-sEV and hGFs-sEV, while hOBs-16k EV promoted adipogenic gene expression compared to that from hPDLCs and hGFs.

CONCLUSIONS

Our proof-of-concept data demonstrate that hOBs-sEV might be an alternative cell-free therapeutic for bone tissue engineering.