Caffeic Acid–coated Nanolayer on Mineral Trioxide Aggregate Potentiates the Host Immune Responses,Angiogenesis, and Odontogenesis

IntroductionThe aim of this study was to investigate whether mineral trioxide aggregate (MTA) can be modified with caffeic acid (CA) to form caffeic acid/mineral trioxide aggregate (CAMTA) cement and to evaluate its physicochemical and biological properties as well as its capability in immune suppression and angiogenesis.MethodsMTA was immersed in trishydroxymethyl aminomethane buffer with CA to allow coating onto MTA powders. X-ray diffractometry and tensile stress-strain tests were conducted to assess for physical characteristics of CAMTA and to evaluate for successful modification of MTA. Then, the CAMTA cement was immersed in simulated body fluid to evaluate its hydroxyapatite formation capabilities and Si release profiles. In addition, RAW 264.7 cells and human dental pulp stem cells were used to evaluate CAMTA’s immunosuppressive capabilities and cell responses, respectively. hDPSCs were also used to assess CAMTA’s angiogenic capabilities.ResultsThe X-ray diffractometry results showed that CA can be successfully coated onto MTA without disrupting or losing MTA’s original structural properties, thus allowing us to retain the initial advantages of MTA. CAMTA was shown to have higher mechanical properties compared with MTA and had rougher pitted surfaces, which were hypothesized to lead to enhanced adhesion, proliferation, and secretion of angiogenic- and odontogenic-related proteins. In addition, it was found that CAMTA was able to enhance hydroxyapatite formation and immunosuppressive capabilities compared with MTA.ConclusionsCAMTA cements were found to have improved physicochemical and biological characteristics compared with their counterpart. In addition, CAMTA cements had enhanced odontogenic, angiogenic, and immunosuppressive properties compared with MTA. All of the results of this study proved that CAMTA cements could be a biomaterial for future clinical applications and tissue engineering use.     

The Role of Integrin αv in Proliferation and Differentiation of Human Dental Pulp Cell Response to Calcium Silicate Cement

Introduction

It has been proved that integrin αv activity is related to cell proliferation, differentiation, migration, and organ development. However, the biological functions of integrin αv in human dental pulp cells (hDPCs) cultured on silicate-based materials have not been explored. The aim of this study was to investigate the role of integrin αv in the proliferation and odontogenic differentiation of hDPCs cultured with the effect of calcium silicate (CS) cement and β-tricalcium phosphate (TCP) cement.

Methods

In this study, hDPCs were cultured on CS and TCP materials, and we evaluated fibronectin (FN) secretion and integrin αv expression during the cell attachment stage. After small interfering RNA transfection targeting integrin αv, the proliferation and odontogenesis differentiation behavior of hDPCs were analyzed.

Results

The results indicate that CS releases Si ion–increased FN secretion and adsorption, which promote cell attachment more effectively than TCP. The CS cement facilitates FN and αv subintegrin expression. However, the FN adsorption and integrin expression of TCP are similar to that observed in the control dish. Integrin αv small interfering RNA inhibited odontogenic differentiation of hDPCs with the decreased formation of mineralized nodules on CS. It also down-regulated the protein expression of multiple markers of odontogenesis and the expression of dentin sialophosphoprotein protein.

Conclusions

These results establish composition-dependent differences in integrin binding and its effectiveness as a mechanism regulating cellular responses to biomaterial surface.     

血管内皮生长因子与牙发生发育的关系

血管内皮生长因子（VEGF）不仅在促进血管内皮细胞分裂与增殖、胚胎发生发育、创伤愈合中发挥着重要的作用,而且在骨的生成与改建过程中,成骨细胞来源的VEGF作用于破骨细胞分化使破骨细胞发生趋化,使局部破骨细胞数目增加并促进局部骨吸收。上皮组织与外胚间叶组织的互相作用贯穿于牙胚发生发育到牙体组织形成的整个过程,内外釉上皮细胞与牙乳头细胞分泌的VEGF及其受体互相作用,促进成釉细胞与成牙本质细胞的分化成熟,影响釉质与牙本质的形成。许多与牙发生相关的基因表达于牙胚中央的釉结中,这些基因涉及的信号转导通路也参与牙的发生。VEGF基因表达受到无翅型小鼠乳房肿瘤病毒整合位点家族/β-连环蛋白信号转导通路的调控。目前,有关VEGF和VEGFR在牙胚发生发育中的认识仅仅停留在表观层面,对于功能及调控机制有待深入的研究。