Potential of dental pulp stem cells and their products in promoting peripheral nerve regeneration and their future applications

Peripheral nerve injury(PNI)seriously affects people’s quality of life.Stem cell therapy is considered a promising new option for the clinical treatment of PNI.Dental stem cells,particularly dental pulp stem cells(DPSCs),are adult pluripotent stem cells derived from the neuroectoderm.DPSCs have significant potential in the field of neural tissue engineering due to their numerous advantages,such as easy isolation,multidifferentiation potential,low immunogenicity,and low transplant rejection rate.DPSCs are extensively used in tissue engineering and regenerative medicine,including for the treatment of sciatic nerve injury,facial nerve injury,spinal cord injury,and other neurodegenerative diseases.This article reviews research related to DPSCs and their advantages in treating PNI,aiming to summarize the therapeutic potential of DPSCs for PNI and the underlying mechanisms and providing valuable guidance and a foundation for future research.

Neural crest derived stem cells from dental pulp and tooth-associated stem cells for peripheral nerve regeneration

The peripheral nerve injuries,representing some of the most common types of traumatic lesions affecting the nervous system,are highly invalidating for the patients besides being a huge social burden.Although peripheral nervous system owns a higher regenerative capacity than does central nervous system,mostly depending on Schwann cells intervention in injury repair,several factors determine the extent of functional outcome after healing.Based on the injury type,different therapeutic approaches have been investigated so far.Nerve grafting and Schwann cell transplantation have represented the gold standard treatment for peripheral nerve injuries,however these approaches own limitations,such as scarce donor nerve availability and donor site morbidity.Cell based therapies might provide a suitable tool for peripheral nerve regeneration,in fact,the ability of different stem cell types to differentiate towards Schwann cells in combination with the use of different scaffolds have been widely investigated in animal models of peripheral nerve injuries in the last decade.Dental pulp is a promising cell source for regenerative medicine,because of the ease of isolation procedures,stem cell proliferation and multipotency abilities,which are due to the embryological origin from neural crest.In this article we review the literature concerning the application of tooth derived stem cell populations combined with different conduits to peripheral nerve injuries animal models,highlighting their regenerative contribution exerted through either glial differentiation and neuroprotective/neurotrophic effects on the host tissue.

Bone morphogenetic protein 7 mediates stem cells migration and angiogenesis:therapeutic potential for endogenous pulp regeneration

Pulp loss is accompanied by the functional impairment of defense,sensory,and nutrition supply.The approach based on endogenous stem cells is a potential strategy for pulp regeneration.However,endogenous stem cell sources,exogenous regenerative signals,and neovascularization are major difficulties for pulp regeneration based on endogenous stem cells.Therefore,the purpose of our research is to seek an effective cytokines delivery strategy and bioactive materials to reestablish an ideal regenerative microenvironment for pulp regeneration.In in vitro study,we investigated the effects of Wnt3a,transforming growth factor-beta 1,and bone morphogenetic protein 7(BMP7)on human dental pulp stem cells(h-DPSCs)and human umbilical vein endothelial cells.2D and 3D culture systems based on collagen gel,matrigel,and gelatin methacryloyl were fabricated to evaluate the morphology and viability of h-DPSCs.In in vivo study,an ectopic nude mouse model and an in situ beagle dog model were established to investigate the possibility of pulp regeneration by implanting collagen gel loading BMP7.We concluded that BMP7promoted the migration and odontogenic differentiation of h-DPSCs and vessel formation.Collagen gel maintained the cell adhesion,cell spreading,and cell viability of h-DPSCs in 2D or 3D culture.The transplantation of collagen gel loading BMP7 induced vascularized pulp-like tissue regeneration in vivo.The injectable approach based on collagen gel loading BMP7 might exert promising therapeutic application in endogenous pulp regeneration.

Therapeutic and regenerative potential of different sources of mesenchymal stem cells for cardiovascular diseases

Mesenchymalstemcells(MSCs)areidealcandidatesfortreatingmanycardiovasculardiseases.MSCscanmodify the internal cardiac microenvironment to facilitate their immunomodulatory and differentiation abilities,which are essential to restore heart function.MSCs can be easily isolated from different sources,including bone marrow,adipose tissues,umbilical cord,and dental pulp.MSCs from various sources differ in their regenerative and therapeutic abilities for cardiovascular disorders.In this review,we will summarize the therapeutic potential of each MSC source for heart diseases and highlight the possible molecular mechanisms of each source to restore cardiac function.

Dental pulp regeneration strategies:A review of status quo and recent advances

Microorganisms,physical factors such as temperature or mechanical injury,and chemical factors such as free monomers from composite resin are the main causes of dental pulp diseases.Current clinical treatment methods for pulp diseases include the root canal therapy,vital pulp therapy and regenerative endodontic therapy.Regenerative endodontic therapy serves the purpose of inducing the regeneration of new functional pulp tissues through autologous revascularization or pulp tissue engineering.This article first discusses the current clinical methods and reviews strategies as well as the research outcomes regarding the pulp regeneration.Then the in vivo models,the prospects and challenges for regenerative endodontic therapy were further discussed.

Tooth regeneration: a revolution in stomatology and evolution in regenerative medicine

A tooth is a complex biological organ and consists of multiple tissues including the enamel, dentin, cementum and pulp. Tooth loss is the most common organ failure. Can a tooth be regenerated？ Can adult stem cells be orchestrated to regenerate tooth structures such as the enamel, dentin, cementum and dental pulp, or even an entire tooth？ If not, what are the therapeutically viable sources of stem cells for tooth regeneration？ Do stem cells necessarily need to be taken out of the body, and manipulated ex vivo before they are transplanted for tooth regeneration？ How can regenerated teeth be economically competitive with dental implants？ Would it be possible to make regenerated teeth affordable by a large segment of the population worldwide？ This review article explores existing and visionary approaches that address some of the above-mentioned questions. Tooth regeneration represents a revolution in stomatology as a shift in the paradigm from repair to regeneration： repair is by metal or artificial materials whereas regeneration is by biological restoration. Tooth regeneration is an extension of the concepts in the broad field of regenerative medicine to restore a tissue defect to its original form and function by biological substitutes.

Human dental pulp stem cells: Applications in future regenerative medicine

Stem cells are pluripotent cells, having a property of differentiating into various types of cells of human body. Several studies have developed mesenchymal stem cells(MSCs) from various human tissues,peripheral blood and body fluids. These cells are then characterized by cellular and molecular markers to understand their specific phenotypes. Dental pulp stem cells(DPSCs) are having a MSCs phenotype and they are differentiated into neuron, cardiomyocytes, chondrocytes, osteoblasts, liver cells and β cells of islet of pancreas. Thus, DPSCs have shown great potentiality to use in regenerative medicine for treatment of various human diseases including dental related problems. These cells can also be developed into induced pluripotent stem cells by incorporation of pluripotency markers and use for regenerative therapies of various diseases. The DPSCs are derived from various dental tissues such as human exfoliated deciduous teeth, apical papilla, periodontal ligament and dental follicle tissue. This review will overview the information about isolation, cellular and molecular characterization and differentiation of DPSCs into various types of human cells and thus these cells have important applications in regenerative therapies for various diseases. This review will be most useful for postgraduate dental students as well as scientists working in the field of oral pathology and oral medicine.

Application of dental stem cells in three-dimensional tissue regeneration

Dental stem cells can differentiate into different types of cells.Dental pulp stem cells,stem cells from human exfoliated deciduous teeth,periodontal ligament stem cells,stem cells from apical papilla,and dental follicle progenitor cells are five different types of dental stem cells that have been identified during different stages of tooth development.The availability of dental stem cells from discarded or removed teeth makes them promising candidates for tissue engineering.In recent years,three-dimensional(3D)tissue scaffolds have been used to reconstruct and restore different anatomical defects.With rapid advances in 3D tissue engineering,dental stem cells have been used in the regeneration of 3D engineered tissue.This review presents an overview of different types of dental stem cells used in 3D tissue regeneration,which are currently the most common type of stem cells used to treat human tissue conditions.

An Overview of the Use of Medicinal Plants in Regenerative Dentistry

Aim: The oral cavity has the particularity to host multiple hard and soft tissues, in this paper, we will discuss the current therapies that lead to cell differentiation by regenerative therapies and the future alternatives proposed by medicinal plants and all the regenerative potential of these different tissues. Material and Methods: A detailed review of the literature through the various search engines: Scopus, PubMed, google scholar, Cochrane, etc., uses the selected keywords to explore the effect of the regenerative potential of several medicinal plants. Results: Through our research, we have proceeded to sort different medicinal plants, according to their repairing and regenerative potential on the different tissues of the oral cavity. Conclusion: Future studies are conceivable to explore the opportunities and potential provided by medicinal plants in the field of regenerative dentistry.

血浆基质在牙髓根尖周病治疗中的应用

血浆基质作为一种自体血液离心产物,具有再生修复的功能,已被广泛应用于口腔颌面部软硬组织再生修复、皮肤美容等领域,并取得了较好的效果。目前,牙髓再生治疗和根尖手术已成为保存牙髓以及保存患牙的主要方法,生物活性材料的应用至关重要,血浆基质作为一种自体生物活性材料,较易获取,可塑性强,具有天然优势。血浆基质可应用于以下情况:①无法刺激根尖出血的根尖孔未闭合年轻恒牙的牙髓血运重建术;②存在骨缺损的根尖屏障术及大面积穿孔髓室底或根侧壁修补术;③大面积根尖病变,伴或不伴随牙周疾病患牙的根尖手术。因血浆基质为自身血液来源制品,使用方面无明显禁忌。虽然已有系统综述表明,相比传统血凝块,血浆基质作为天然再生支架,可有效促进牙髓根尖周病的再生性修复。然而,由于血浆基质的特性受不同制备方式的影响,其适用范围有所差异。此外,目前尚缺乏血浆基质长期的临床研究结果,且组织学证据较难获取,仍然需要大量的体内外研究进一步探索。本文将对不同血浆基质在牙髓再生、根尖手术中的骨组织再生等方面的应用进行阐述,以期为临床医生在适应证选择及预后评估时提供参考。

甲基丙烯酸酐改性明胶/经处理牙本质基质生物活性支架的制备及性能

背景:牙髓-牙本质再生一直是近几年研究的热点及难点,构建复合生物支架材料为牙髓-牙本质再生提供了新的思路与方法。目的:观察甲基丙烯酸酐改性明胶/经处理牙本质基质支架对人牙髓干细胞增殖、迁移与成骨分化的影响。方法:将不同质量的经处理牙本质基质分散至甲基丙烯酸酐改性明胶溶液中,使甲基丙烯酸酐改性明胶与经处理牙本质基质的质量比分别为2∶1、1∶1、1∶2,采用冷冻干燥法制备甲基丙烯酸酐改性明胶/经处理牙本质基质支架,检测支架的微观形貌、吸水率及机械性能。采用不同质量比的支架浸提液、DMEM培养基(对照组)分别培养人牙髓干细胞,检测细胞增殖与迁移情况。采用不同质量比的支架浸提液+成骨诱导液、DMEM培养基+成骨诱导液(对照组)分别培养人牙髓干细胞,碱性磷酸酶染色分析成骨能力。结果与结论:①扫描电镜下可见3组支架均具有多孔结构,随着支架中经处理牙本质基质质量的增加,支架的孔隙率升高,组间两两比较差异有显著性意义(P<0.05);随着支架中经处理牙本质基质质量的增加,支架的吸水率升高,组间两两比较差异有显著性意义(P<0.05);随着支架中经处理牙本质基质质量的增加,支架的抗压强度、剪切强度增大。②CCK-8检测显示培养3,5,7 d,2∶1、1∶1、1∶2支架组细胞增殖吸光度值均高于对照组(P<0.05),并且随着支架中经处理牙本质基质质量的增加,细胞增殖吸光度值升高(P<0.05);细胞划痕实验显示2∶1、1∶1、1∶2支架组细胞迁移率均大于对照组(P<0.05),并且随着支架中经处理牙本质基质质量的增加,细胞迁移率增大(P<0.05)。③碱性磷酸酶染色显示,2∶1、1∶1、1∶2支架组细胞成骨分化能力均强于对照组,并且随着支架中经处理牙本质基质质量的增加,细胞成骨能力增强。④结果表明,甲基丙烯酸酐改性明胶与经处理牙本质基质质量比为1∶2的支架最适合牙髓干细胞的增殖与分化。

外泌体及预处理方式对牙髓再生的作用

背景:现有研究已经证实外泌体可有效促进牙髓再生,而经预处理来源的外泌体其生物学功能和特性会发生显著改变,对细胞的增殖、迁移和成牙分化产生不同的影响。目的:探讨外泌体及其预处理方式在牙髓再生领域的应用现状,归纳和总结影响外泌体发挥作用的预处理方式,并阐述外泌体及其预处理方式对牙髓再生的作用。方法:检索万方、中国知网、PubMed和Web of Science数据库中2006-2022年发表的相关文献,以“外泌体,牙髓再生,预处理方式”等为中文检索词,以“Exosomes,Pulp regeneration,Preconditioning method”等为英文检索词进行检索,共纳入78篇文献进行综述分析。结果与结论:①外泌体具有良好的生物相容性、低免疫原性和无细胞毒性等优势,可以通过促进干细胞成牙、成神经和成血管化进而诱导牙髓组织的新生。②经预处理衍生的外泌体可以增强对组织的修复和再生能力,并对再生牙髓的质量有显著影响。③目前应用在牙髓再生领域中的预处理方式包括炎症刺激、低氧诱导、条件培养基和三维培养,其分泌的外泌体均能有效改善再生牙髓的质量,但是不同的预处理方式对牙髓再生的具体效果和机制在未来尚需探索。

次氯酸溶液的稳定性及对口腔组织刺激性的体外研究

目的:研究不同次氯酸(hypochlorous acid,HClO)溶液在模拟临床使用条件下的理化性能及杀灭粪肠球菌的稳定性,并检测HClO对口腔软、硬组织和细胞的相容性。方法:在模拟条件下监测2种不同生产工艺HClO样本的理化指标(有效氯浓度、氧化还原电位和pH值)变化,通过悬液定量杀菌试验测定不同浓度梯度HClO溶液的杀菌对数值。将牙髓组织、舌组织及牙本质块分别浸泡于PBS、100 ppm HClO、200 ppm HClO和3%NaClO 4组溶液中,用称重法和显微硬度仪检测其对软、硬组织的影响。通过CCK-8法检测HClO、NaClO及其10倍稀释液对人牙龈成纤维细胞的毒性作用。采用GraphPad PRIS 8.0软件对数据进行统计学分析。结果:在模拟条件下,HClO溶液的有效氯浓度随时间缓慢衰减,1个月内衰减程度<20 ppm,pH值及氧化还原电位值相对稳定。各样本浓度衰减前后其杀菌对数值均>5.00,HClO处理后的软组织重量及牙本质显微硬度值无显著改变(P>0.05),HClO及其10倍稀释液处理5 min的细胞活性远高于NaClO(P<0.001)。结论:HClO溶液的理化性能及杀菌稳定性良好,能满足临床需求。相比NaClO,HClO细胞毒性低、组织相容性好,有望成为牙髓再生领域安全高效的消毒产品。

年轻恒牙牙髓疾病的临床治疗进展

年轻恒牙因萌出不久,形态结构未发育完全,表现为髓腔大、髓角高尖,根尖孔开放。龋病、牙发育异常或创伤可能导致牙髓受到损伤或感染,甚至进一步发生牙髓坏死,从而直接影响到牙根的正常发育。因此,年轻恒牙牙髓疾病的治疗在临床上是一大挑战。临床治疗的目标是尽量保存活髓,并促进患牙牙根继续发育,使根管壁增厚,根尖孔闭合。该文系统综述因牙髓暴露引起的可复性和不可复性牙髓炎患牙的治疗方案,旨在为年轻恒牙牙髓病变的治疗提供依据,重点为保留健康牙髓、促进牙髓的修复与再生提供参考。

光交联复合水凝胶支架中人牙髓干细胞的成骨/成牙分化能力

背景:甲基丙烯酸酐改性明胶(gelatin-methacryloyl,Gel-MA)与经处理牙本质基质(treated dentin matrix,TDM)在一定比例下经过紫外线交联后形成的复合水凝胶支架具有良好的孔隙率、机械性能、溶胀性能及生物降解率,这为临床上年轻恒牙的牙髓再生提供了新的思路和方法。目的:探究1∶2质量比Gel-MA/TDM复合光交联水凝胶支架对人牙髓干细胞增殖能力及成骨/成牙本质分化能力的影响。方法:将第3代牙髓干细胞接种至1∶2质量比Gel-MA/TDM复合水凝胶支架中,采用CCK-8实验检测人牙髓干细胞在复合水凝胶支架中的增殖能力。将第3代牙髓干细胞接种至1∶2质量比Gel-MA/TDM复合水凝胶支架中并进行成骨诱导,采用碱性磷酸酶染色及茜素红染色观察矿化结节的形成情况,采用RT-PCR检测成牙相关因子(牙本质基质蛋白1、牙本质涎磷蛋白)和成骨相关因子(骨钙素、Runt相关转录因子2)的基因表达。结果与结论:①CCK-8检测结果显示,前7 d的牙髓干细胞增殖能力明显升高,第10天时速度减缓;②碱性磷酸酶染色及茜素红染色结果显示,Gel-MA/TDM复合水凝胶组牙髓干细胞的碱性磷酸酶活性及矿化结节生成强于单纯Gel-MA水凝胶组(P<0.05);③RT-PCR结果显示,Gel-MA/TDM复合水凝胶组牙髓干细胞中牙本质基质蛋白1、牙本质涎磷蛋白、骨钙素、Runt相关转录因子2的基因表达量明显高于单纯Gel-MA水凝胶组(P<0.05),且14 d基因表达量明显高于7 d(P<0.05)。结果表明,培养在1∶2 Gel-MA/TDM复合水凝胶支架上的牙髓干细胞表现出较好的增殖能力,能够强化牙髓干细胞的成骨、成牙本质分化能力。

石墨烯及其衍生物的理化性质和应用研究进展

近年来研究显示,石墨烯及其衍生物具有良好的理化性质和生物相容性,可促进细胞增殖和干细胞分化。牙髓再生涉及种子细胞增殖和分化,提示石墨烯及其衍生物有望应用于牙髓再生。然而,石墨烯及其衍生物的理化性质是否适合髓腔环境及其对牙髓再生种子细胞的具体作用等均未见报道。本文对石墨烯及其衍生物的理化性质、细胞学作用和在组织工程中的应用情况进行综述,为将其应用于牙髓再生研究提供参考。

负载骨形态发生蛋白2水凝胶诱导牙髓干细胞的成骨分化

背景:前期研究证明,甲基丙烯酸酐改性明胶/经处理牙本质基质复合水凝胶支架可促进人牙髓干细胞的增殖及分化。水凝胶负载骨形态发生蛋白2被认为是骨修复中有前景的材料。目的:观察负载不同质量浓度骨形态发生蛋白2的甲基丙烯酸酐改性明胶/经处理牙本质基质复合水凝胶对人牙髓干细胞成骨向分化的诱导作用。方法:制备含0,50,100,200μg/mL骨形态发生蛋白2的甲基丙烯酸酐改性明胶/经处理牙本质基质复合水凝胶,分别记为GelMA/TDM、BMP-2(50 ng/mL)GelMA/TDM、BMP-2(100 ng/mL)GelMA/TDM、BMP-2(200 ng/mL)GelMA/TDM,检测复合水凝胶对骨形态发生蛋白2的体外缓释性能。采用改良组织块酶消化法提取人牙髓干细胞,分别接种于4种水凝胶表面,采用CCK-8法检测细胞增殖,DAPI染色检测细胞黏附;对各组水凝胶表面的人牙髓干细胞进行成骨诱导,进行碱性磷酸酶染色、碱性磷酸酶活性检测与茜素红染色,采用RT-PCR法检测相关成骨基因(Runx2、骨形态发生蛋白2、骨桥蛋白、骨钙素、Ⅰ型胶原)表达。结果与结论:①甲基丙烯酸酐改性明胶/经处理牙本质基质复合水凝胶可持续释放骨形态发生蛋白2长达21 d,在第3-6天释放较快,第6天之后释放趋于平稳;②4种水凝胶均可促进人牙髓干细胞的增殖,其中以BMP-2(100 ng/mL)-GelMA/TDM复合水凝胶的作用最明显;相较于GelMA/TDM复合水凝胶,BMP-2-GelMA/TDM复合水凝胶可促进人牙髓干细胞的黏附,其中以BMP-2(200 ng/mL)-GelMA/TDM复合水凝胶的作用最明显;③相较于GelMA/TDM复合水凝胶,BMP-2-GelMA/TDM复合水凝胶可提升碱性磷酸酶活性、钙结节含量与相关成骨基因表达,综合分析显示BMP-2(100 ng/mL)-GelMA/TDM复合水凝胶的作用更明显;④结果表明,BMP-2(100 ng/mL)-GelMA/TDM复合水凝胶促进牙髓干细胞成骨向分化的能力更明显。

DSPP与BMP-2在牙髓干细胞修复再生牙髓牙本质复合体中的表达及意义

目的 探讨牙本质涎磷蛋白(dentin sialophosphoprotein,DSPP)与骨形态发生蛋白-2(bone morphogenetic protein-2,BMP-2)在第三代同质异体牙髓干细胞(dental pulp stem cell,DPSCs)再生修复牙髓牙本质复合体后的表达和意义,为年轻恒牙牙髓根尖周疾病提供新的诊疗思路。方法 18只SD大鼠随机分为实验组和对照组,两组均在全麻下摘除大鼠上颌双侧第一磨牙冠髓,实验组同期髓腔定植体外培养的同质异体大鼠牙髓干细胞,对照组冠髓摘除后不进行任何处理,术后均使用玻璃离子充填封闭髓腔。两组动物均于术后2、4、6周处死,取其上颌骨进行免疫组织化学方法检测DSPP和BMP-2的表达。结果 术后2、4、6周时,实验组牙髓牙本质复合体处的DSPP、BMP-2的表达水平均高于对照组,差异有统计学意义(P<0.05)。结论 同质异体牙髓干细胞再植后会增加牙髓牙本质复合体处的DSPP和BMP-2的表达,有助于修复再生牙髓牙本质复合体。

再生性牙髓治疗的研究进展

牙髓作为牙体结构中唯一的软组织结构,具有感觉、营养等诸多功能,但牙髓本身却极易受到外界因素影响而坏死。目前针对牙髓坏死最常用的治疗办法是根管治疗术,但根管治疗后的牙齿容易发生二次感染,出现牙根纵裂等不良预后。再生性牙髓治疗旨在替换受损牙齿结构的生物程序,包括牙本质、牙根结构以及牙髓-牙本质复合体的细胞,展现出了解决临床症状、实现牙根甚至牙髓再生等巨大优势。在牙髓干细胞被发现后,再生性牙髓治疗又展现出了新的活力,细胞移植、细胞归巢等治疗方案发展迅速并展现出广阔的应用前景。

由外泌体介导的牙髓再生相关信号通路研究进展

外泌体属于细胞外囊泡的一种,通过受体介导的交互作用直接刺激靶细胞,或通过向靶细胞转移各种生物活性分子发挥其生物学功能,在细胞与其微环境之间的细胞间通信中起关键作用。牙髓再生是指从组织工程的角度,将支架、干细胞及信号因子相结合植入到经过适当处理后的牙髓腔里,在支架和信号因子的作用下,干细胞增殖分化形成牙髓牙本质复合物,恢复牙髓的功能。近年来研究发现,p38MAPK信号通路、TGF⁃β/Smad信号通路、Wnt/β⁃catenin信号通路以及其他一些相关信号通路是外泌体调控牙髓再生的重要信号通路,在牙髓再生中起着关键的作用。因此,该文基于外泌体调控牙髓再生的相关信号通路的作用机制及研究进展作一综述。