Low-intensity pulsed ultrasound promotes tissue regeneration in rat dental follicle cells in a porous ceramic scaffold

Abstract The aim of this study was to investigate the effects of low-intensity pulsed ultrasound (LIPUS) on the osteogenic differentiation of dental follicle cells (DFCs) in vitro and on the regenerative effects of DFC-OsteoBoneTM complexes in vivo. DFCs were isolated and characterized. In the in vitro study, DFCs were cultured in an osteogenic medium in the presence or absence of LIPUS. The expression levels of ALP, Runx2, OSX, and COL-I mRNA were analyzed using real-time polymerase chain reaction (RT-PCR) on day 7. Alizarin red staining was performed on day 21. The state of the growth of the DFCs that were seeded on the scaffold at 3, 5, 7, and 9 days was detected by using a scanning electron microscope. In our in vivo study, 9 healthy nude mice randomly underwent subcutaneous transplantation surgery in one of three groups: group A, empty scaffold; group B, DFCs + scaffold; and group C, DFCs + scaffold + LIPUS. After 8 weeks of implantation, a histological analysis was performed by HE and Mason staining. Our results indicate that LIPUS promotes the osteogenic differentiation of DFCs by increasing the expression of the ALP, Runx2, OSX, and COL-I genes and the formation of mineralized nodules. The cells can adhere and grow on the scaffolds and grow best at 9 days. The HE and Mason staining results showed that more cells, fibrous tissue and blood vessels could be observed in the DFCs + scaffold + LIPUS group than in the other groups. LIPUS could promote the osteogenic differentiation of DFCs in vitro and promote tissue regeneration in a DFCs-scaffold complex in vivo. Further studies should be conducted to explore the underlying mechanisms of LIPUS.

Comparative in vitro evaluation of human dental pulp and follicle stem cell commitment

Objective: Pulp and periodontal tissues are well-known sources of mesenchymal stem cells [MSCs] that provide a promising place in tissue engineering and regenerative medicine. The molecular mechanisms underlying commitment and differentiation of dental stem cells that originate from different dental tissues are not fully understood. In this study, we have compared the expression levels of pluripotency factors along with immunological and developmentally-related markers in the culture of human dental pulp stem cells [hDPSCs], human dental follicle stem cells [hDFSCs], and human embryonic stem cells [hESCs]

Materials and Methods: In this experimental study, isolated human dental stem cells were investigated using quantitative polymerase chain reaction [qPCR], immunostaining, and fluorescence-activated cell sorting [FACS]. Additionally, we conducted gene ontology [GO] analysis of differentially expressed genes and compared them between dental stem cells and pluripotent stem cells

Results: The results demonstrated that pluripotency [OCT4 and SOX2] and immunological [IL-6 and TLR4] factors had higher expressions in hDFSCs, with the exception of the JAGGED-1/NOTCH1 ratio, c-MYC and NESTIN which expressed more in hDPSCs. Immunostaining of OCT4, SOX2 and c-MYC showed cytoplasmic and nucleus localization in both groups at similar passages. GO analysis showed that the majority of hDFSCs and hDPSCs populations were in the synthesis [S] and mitosis [M] phases of the cell cycle, respectively

Conclusion: This study showed different status of heterogeneous hDPSCs and hDFSCs in terms of stemness, differentiation fate, and cell cycle phases. Therefore, the different behaviors of dental stem cells should be considered based on clinical treatment variations

Orthodontic movement in deciduous teeth

Deciduous teeth exfoliate as a result of apoptosis induced by cementoblasts, a process that reveals the mineralized portion of the root while attracting clasts. Root resorption in deciduous teeth is slow due to lack of mediators necessary to speed it up; however, it accelerates and spreads in one single direction whenever a permanent tooth pericoronal follicle, rich in epithelial growth factor (EGF), or other bone resorption mediators come near. The latter are responsible for bone resorption during eruption, and deciduous teeth root resorption and exfoliation. Should deciduous teeth be subjected to orthodontic movement or anchorage, mediators local levels will increase. Thus, one should be fully aware that root resorption in deciduous teeth will speed up and exfoliation will early occur. Treatment planning involving deciduous teeth orthodontic movement and/or anchorage should consider: Are clinical benefits relevant enough as to be worth the risk of undergoing early inconvenient root resorption?.

O dente decíduo é esfoliado graças à apoptose em seus cementoblastos, que desnuda a parte mineralizada da raiz e atrai os clastos. A rizólise é lenta, pois faltam mediadores em quantidade para acelerar o processo, mas ela se acelera e unidireciona quando se aproxima um folículo pericoronário de dente permanente rico em EGF e outros mediadores da reabsorção óssea - os responsáveis pelas reabsorções óssea na erupção e dentária decídua na rizólise e esfoliação. Se houver movimentação ortodôntica ou ancoragem em dentes decíduos, aumenta-se, também, o nível local desses mesmos mediadores, devendo-se estar bem consciente de que haverá uma aceleração da rizólise e, em decorrência, uma antecipação de sua esfoliação. No planejamento de casos em que dentes decíduos estejam envolvidos na movimentação ortodôntica e/ou ancoragem, deve-se ponderar: o benefício clínico para o paciente será relevante, a ponto de valer o risco de uma rizólise abreviada e inconveniente?.

Aislación y caracterización de células madre mesenquimales provenientes de pulpa y folículo dentario humano / Isolation and characterization of mesenchymal stem cells from human dental pulp and follicle

Recientemente se ha descubierto que diversos tejidos dentales son fuente importante de Células Madre Mesenquimales (CMM). En la cavidad oral podemos encontrar CMM en la pulpa, en el folículo dental, papila y en la encía entre otros lugares. Varios estudios avalan el extenso potencial terapéutico de las CMM en terapias de regeneración. El objetivo de este estudio es aislar, cultivar células madres mesenquimales de pulpa y folículo dental humano, caracterizar su inmunofenotipo y su potencial de diferenciación a linaje osteogénico, condrogénico y osteogénico. Se cultivaron células de pulpa y folículo dental de terceros molares de dientes permanentes jóvenes humanos. Los cultivos de CMM fueron monitoreados por microscopia óptica, las células se inmunotipificaron por citometría de flujo. Posteriormente se evaluó su capacidad de diferenciaron a los tres linajes mencionados. En estas condiciones experimentales se comprobó que las células aisladas y cultivadas de pulpa y folículo dental correspondían a células madre mesenquimales humanas, siendo éstas últimas más fáciles de obtener y proliferar. Las CMM de folículo dental poseen mayor potencial de crecimiento y capacidad de diferenciación en comparación a las CMM de pulpa dental, probablemente debido a su estado evolutivo más inmaduro.

It was recently discovered that dental tissues are important sources of mesenchymal stem cells (MSCs). In the oral cavity MSCs can be found in the pulp, dental follicle, apical papilla and gingival tissue, among others. Many studies support the therapeutic potential of MSCs in regenerative therapies. The objective of this study was to isolate and culture mesenchymal stem cells from human dental pulp and follicle, and to characterize their immunophenotype and differentiation potential to adipogenic, chondrogenic and osteogenic lineages. Oral cavity stem cells were cultured from pulp and dental follicle of wisdom teeth from young permanent teeth. Immunotypification of MSCs was performed by flow cytometry and cultures were evaluated for their ability to differentiate into the three lineages mentioned. Our results corroborate that cultured oral MSC cells isolated from pulp and dental follicle were mesenchymal in origin, being the latter more easy to obtain. Dental follicle MSCs have greater growth potential and differentiation capacity compared to dental pulp MSCs, probably due to their more immature developmental state.

Mesenchymal stem cells in the dental tissues: perspectives for tissue regeneration

In recent years, stem cell research has grown exponentially owing to the recognition that stem cell-based therapies have the potential to improve the life of patients with conditions that range from Alzheimer’s disease to cardiac ischemia and regenerative medicine, like bone or tooth loss. Based on their ability to rescue and/or repair injured tissue and partially restore organ function, multiple types of stem/progenitor cells have been speculated. Growing evidence demonstrates that stem cells are primarily found in niches and that certain tissues contain more stem cells than others. Among these tissues, the dental tissues are considered a rich source of mesenchymal stem cells that are suitable for tissue engineering applications. It is known that these stem cells have the potential to differentiate into several cell types, including odontoblasts, neural progenitors, osteoblasts, chondrocytes, and adipocytes. In dentistry, stem cell biology and tissue engineering are of great interest since may provide an innovative for generation of clinical material and/or tissue regeneration. Mesenchymal stem cells were demonstrated in dental tissues, including dental pulp, periodontal ligament, dental papilla, and dental follicle. These stem cells can be isolated and grown under defined tissue culture conditions, and are potential cells for use in tissue engineering, including, dental tissue, nerves and bone regeneration. More recently, another source of stem cell has been successfully generated from human somatic cells into a pluripotent stage, the induced pluripotent stem cells (iPS cells), allowing creation of patient- and disease-specific stem cells. Collectively, the multipotency, high proliferation rates, and accessibility make the dental stem cell an attractive source of mesenchymal stem cells for tissue regeneration. This review describes new findings in the field of dental stem cell research and on their potential use in the tissue regeneration.

Nos últimos anos, as pesquisas com células tronco têm aumentado exponencialmente devido ao reconhecimento de que seu potencial terapêutico pode melhorar a qualidade de vida de pacientes com diversas doenças, como a doença de Alzheimer, isquemias cardíacas e, até mesmo, nas pesquisas de medicina regenerativa que visa uma possível substituição de órgão perdidos, como por exemplo, os dentes. Baseado em habilidades de reparar tecidos injuriados e restaurar parcialmente as funções de um órgão, diversos tipos de células-tronco têm sido estudadas. Recentes evidências demonstram que as células-tronco são primariamente encontradas em nichos e que certos tecidos apresentam mais células-tronco que outros. Entre estes, os tecidos dentais são considerados como uma fonte rica de células-tronco mesenquimais adequado para aplicações em engenharia tecidual. Sabe-se que estas células têm o potencial de diferenciarem-se em diversos tipos celulares, incluindo osteoblastos, células progenitoras de neurônios, osteoblastos, condrócitos e adipósitos. Na odontologia, a biologia celular e a engenharia tecidual são de grande interesse, pois fornecem inovações na geração de novos materiais clínicos e ou na regeneração tecidual. Estas podem ser isoladas e crescidas em diversos meios de cultura apresentando grande potencial para ser usada na engenharia tecidual, incluindo regeneração de tecidos dentais, nervos e ossos. Recentemente, outra fonte de células tronco tem sido geradas a partir de células somáticas de humanos a um estágio de pluripotência, chamados de células-tronco pluripotente induzida (iPS) levando à criação de células-tronco específicas. Coletivamente, a multipotencialidade, altas taxas de proliferação e acessibilidade, faz das células-tronco dentárias uma fonte atrativa de células-tronco mesenquimais para regeneração tecidual. Esta revisão descreve novos achados no campo da pesquisa com células-tronco dentais e seu potencial uso na regeneração tecidual.

Bovine cementum extrac influences murine dental follicle cells in vitro

This study evaluated the attachment, chemo-attractive, proliferative and mineralization inductive potential of a bovine cementum extract (CPE) on newborn murine dental follicle cells (MDFC) in vitro. Cementum extract was partially purified by DEAE-cellulose chromatografy. A band representing and Mr of 55,000 was excised form the fel and the protein (s) were electroeluted. Attachment assays revealed that CPE (1.0 µg/ml) promoted MDFC attachment by 96 percent in comparison with collagen type I (5 µg/ml), and was five-fold greater compared with serum-free media (SFM), (p<0.05). Between 1 and 5 days CPE at 1.0 µg/ml and collagen type I at 5 µg/ml sustained more than 75 percent attachement and spreading of MDFC when compared to SFM (P<0.05). Contrary to other reports, fibronectin (0.5 µg/ml) was more potent than CPE in promoting MDFC chemoattraction (P<0.05). MDFC proliferation was stimulated by CPE (0.125 µg/ml), but this response was elicited only when CPE was used together with 10 percent FBS (37.3 percent) or 0.2 percent FBS (76 percent) (p<0.05). Alkaline phosphatase expression by MDFC was increased by CPE (1.0 µg/ml), in comparison to the control. Calcium deposits were detected by von Kossa staining in 14-day MDFC cultures treated with CPE. Nodule formation and its mineralization in long-term MDFC cultures were induced by CPE (1.0 µg/ml). Molecules(s) contained in CPE appear to regulate various biological activities in MDFC, indicating that CPE could play a key role in selecting progenitor cells required for the process of cementogenesis during development

Caracterizaçäo microscópica de folículos pericoronários de dentes näo-irrompidos e parcialmente irrompidos: sua relaçäo com a idade / Microscophic characterization of pericoronary follicles of non-erupted and partially erupted teeth: their relationship to the age

Foram analisados microscopicamente 191 folículos pericoronários, sendo 155 de dentes näo-irrompidos e 36 parcialmente irrompidos, com o objetivo de estabelecer os parâmetros de normalidade para tais estruturas, sugerindo-se critérios para o seu diagnóstico. Na caracterizaçäo dos folículos pericoronários foram consideradas as modificaçöes sofridas em decorrência da idade e do estado de erupçäo dental, bem como as prováveis alteraçöes que pudessem ser relacionadas com a etiopatogenia e prevalência das patologias associadas a dentes näo-irrompidos quer seja de natureza cística ou neoplásica. Os espécimes foram processados pelos procedimentos técnicos de rotina, coroados pela hematoxilina-eosina e analisados através da microscopia de luz. Na análise microscópica dos folículos pericoronários foram consideradas as estruturas e alteraçöes visualizadas no revestimento epitelial, na parede conjuntiva e nas ilhotas epiteliais odontogênicas subepiteliais e profundas. Pelos resultados obtidos estabeleceu-se um padräo estrutural e organizacional para a análise microscópica de folículos pericoronários de dentes näo-irrompidos e parcialmente irrompidos. As contataçöes realizadas levaram às seguintes conclusöes: 1) Existe, microscopicamente, um padräo estrutural e organizacional para folículos pericoronários de dentes näo-irrompidos e parcialmente irrompidos; 2) A idade e a inflamaçäo säo fatores modificadores dos folículos pericoronários pela induçäo e alteraçöes de natureza metaplásica; 3) A origem das ilhotas epiteliais odontogênicas subepiteliais ocorre a partir das camadas mais externas do epitélio reduzido do esmalte através de um processo de pregueamento, desaparecendo com a idade; 4) A reduçäo numérica das ilhotas epiteliais odontogênicas profundas se dá principalmente pela presença da inflamaçäo, mas hialinizaçäo e a mineralizaçäo também contribuem para sua involuçäo com o aumento da idade do paciente; 5) O quadro microscópico isolado de um cisto dentígero, especialmente os incipientes, näo permite um diagnóstico diferencial seguro com folículo pericoronário de dente näo-irrompido...