NOVEL THERAPEUTICS TO TREAT NECROTIC TEETH: THE COMBINATORIAL EFFECT OF A 3D DRUG DELIVERY SYSTEM AND SPATIALLY DESIGNED STEM CELL NICHES

摘要/总结： 龋齿和牙齿创伤是主要的口腔健康负担。全球21%的儿童（6至11岁） 他们的恒牙有龋齿。在美国，18%的学龄儿童经历过牙齿创伤。牙髓损伤 由于龋齿或创伤，导致炎症，如果不治疗，会导致坏死。传统 坏死的未成熟恒牙的治疗允许感染控制，但既不支持牙根 牙髓免疫活性的发育或恢复。迄今为止，没有临床治疗存在， 促进根管消毒，并能持续引导牙髓和牙本质的生长和发育， 坏死的牙齿因此，迫切需要开发一种可预测的牙髓牙本质再生策略， 一个无菌的环境，最终可能导致建立新的治疗方法来治疗 牙髓坏死的未成熟牙齿。本申请的目的是开发一种新的策略，以刺激 牙髓和牙本质再生的可注射胶原纤维基质系统工程与异质 硬度和选定的生长因子（GF），这将首先需要实现无菌生态位。我们 第一个假设是，静电纺丝可用于开发无毒和抗菌有效的3D管状 用于根管消毒的药物递送结构， 影响了几天。将评价拟定结构的释放特性和细胞 体外相容性将使用体外感染的牙齿切片模型来确定抗菌特性， 未成熟的狗牙齿与根尖周病的体内模型（目的1）。我们的第二个假设是 牙髓干细胞移植在加入骨形态发生蛋白-2（BMP-2）的硬胶原基质中 或在加入血管内皮生长因子（VEGF）的更柔顺的基质内， 注射到消毒的根管中，将分别导致牙本质和牙髓再生。我们建议 通过评价细胞活力，增殖， 凋亡和分化为内皮细胞和成牙本质细胞， 建立了牙片SCID小鼠体内模型（目的2）。最后，给出了最佳和最佳的再生容量， 将使用未成熟狗的体内模型评价标准化的可注射胶原-原纤维基质系统 用药物递送结构消毒后患有根尖周病的牙齿（目的3）。本申请是 高度创新，因为我们首次提出了细胞友好的静电纺丝3D管状药物的临床作用 用于根管消毒的递送构造。此外，我们建议将这种疗法与一种独特的 使用可注射和高度可调的胶原-原纤维基质扩增牙髓干的再生策略 细胞分化形成牙髓和牙本质的适当位置。所提出的研究是有意义的 因为它将加速建立一种可靠的再生疗法来治疗坏死的未成熟的 恒牙

Abstract/Summary: Caries and dental trauma are major oral health burdens. Globally, 21% of children (age 6 to 11 years) have caries in their permanent teeth. In the US, 18% of school children experience dental trauma. Dental pulp injury due to caries or trauma, leads to inflammation, which if left untreated, results in necrosis. Traditional therapeutics of necrotic immature permanent teeth allows for infection control, but support neither root development nor restoration of the immunocompetence of the pulp. To date, no clinical therapy exists that promotes root canal disinfection and can consistently guide the growth and development of pulp and dentin in necrotic teeth. Thus, there is a pressing need to develop a strategy for predictable pulp-dentin regeneration in a bacteria-free environment which may ultimately lead to the establishment of novel therapeutics to treat immature teeth with pulpal necrosis. The objective of this application is to develop a novel strategy to stimulate pulp and dentin regeneration by engineering an injectable collagen-fibril matrix system with heterogeneous stiffness and selected growth factors (GFs), which will first require the attainment of a bacteria-free niche. Our first hypothesis is that electrospinning can be used to develop non-toxic and antimicrobially effective 3D tubular drug delivery constructs for root canal disinfection that release initially high amount of antibiotics and sustain its effects for several days. The proposed construct will be evaluated for its release properties and cell compatibility in vitro. Antimicrobial properties will be determined using an in vitro infected tooth slice model and an in vivo model of immature dog teeth with periapical disease (Aim 1). Our second hypothesis is that dental pulp stem cell transplantation within a stiffer collagen matrix added with bone morphogenetic protein-2 (BMP-2) or within a more compliant matrix added with vascular endothelial growth factor (VEGF), when concentrically injected into a disinfected root canal, will lead to dentin and pulp regeneration, respectively. We propose to optimize the novel self-assembling collagen-fibril matrix system by evaluating the cell viability, proliferation, apoptosis and differentiation to endothelial and odontoblast cells using in vitro cell-based assays and a well- established in vivo tooth slice SCID mice model (Aim 2). Finally, the regenerative capacity of the optimal and standardized injectable collagen-fibril matrix system will be evaluated using an in vivo model of immature dog teeth with periapical disease after disinfection with the drug delivery construct (Aim 3). This application is highly innovative as we propose, for the first time, the clinical role of a cell-friendly electrospun 3D tubular drug delivery construct for root canal disinfection. Further, we propose to couple this therapy with a unique regenerative strategy using injectable and highly tunable collagen-fibril matrices to amplify dental pulp stem cell differentiation to form pulp and dentin in the appropriate locations. The proposed research is significant because it will expedite the establishment of a reliable regenerative therapeutics to treat necrotic immature permanent teeth.