Developing a Novel Vascularized Bone Microdevice for Investigating the Post-Stroke Bone Microenvironment

项目摘要 缺血性中风是一种严重的疾病，在美国每年影响近80万人，是一种严重的疾病。 长期残疾的主要原因。尽管中风幸存者通常会经历加速的骨质流失， 与典型的老年人相比，骨折风险更高，其根本原因仍然知之甚少， 不能仅仅用卧床休息来解释。卒中后血清中存在炎性细胞因子，但 细胞因子失调是中风后骨重塑改变的驱动因素-如在炎症性疾病中所见， 与其他疾病如关节炎相关的骨质流失-尚不清楚。我们的主要假设是 中风后所见的环境刺激骨脉管系统中的促炎反应， 成骨细胞的活性和驱动分泌蛋白质的增加，以激活骨吸收程序。微器件 和“器官芯片”构建体是有效的3D体外平台，用于机械地探测不同的细胞-细胞 在受控的微环境中相互作用。这种微型装置已成功地用于检查 骨内不同的壁龛对药物，辐射和遗传疾病的反应，但他们没有 还被用于检查矿化骨和血管的相互作用。该项目的总体目标是扩大 了解导致卒中相关骨丢失的潜在因素，特别是炎症因子， 开发和实现模拟矿化骨的骨血管微器件平台 微环境目标1将确定最佳的生产条件， 细胞外基质（ECM）支架用于微装置中的成骨细胞支撑。目标2将开发新的骨- 血管微装置平台，并研究稳态下成骨细胞-内皮细胞的相互作用 条件目的3将确定炎性细胞因子白细胞介素-6，白细胞介素-1 β和干扰素- γ对成骨细胞-内皮细胞旁分泌信号传导的影响。我们将实现这些目标 通过利用具有被动矿物质沉积的传统ECM支架制造技术， 流体剪切和营养物运输的动力学建模，以及成骨细胞活性的生物测定， 血管屏障功能这项工作将创造一个新的体外平台，使机械探测， 复杂的骨-血管相互作用和对骨丢失的炎症调节的深入了解， 中风，从而提供一个框架，可以告知更好的治疗策略，以减轻中风相关的骨骼 脆弱

PROJECT SUMMARY Ischemic stroke is a serious condition affecting nearly 800,000 people in the United States annually and is a leading cause of long-term disability. Although stroke survivors commonly experience accelerated bone loss and higher fracture risk compared to typically aging adults, the underlying causes remain poorly understood and cannot be explained solely by bedrest. Inflammatory cytokines are present in serum post-stroke, but whether cytokine dysregulation is a driving factor for altered bone remodeling following stroke – as seen in inflammatory- related bone loss in other conditions like arthritis – is unknown. Our primary hypothesis is that the inflammatory environment seen post-stroke stimulates a pro-inflammatory response in bone vasculature that acts to suppress osteoblast activity and drive an increase in secreted proteins to activate bone resorptive programs. Microdevices and “organ-on-chip” constructs are effective 3D in vitro platforms for mechanistically probing different cell-cell interactions in controlled microenvironments. Such microdevices have been used successfully to examine the response of different niches within bone to pharmaceuticals, radiation, and genetic disorders, but they have not yet been used to examine mineralized bone and vascular interactions. The overall goal of this project is to expand understanding of underlying factors contributing to stroke-related bone loss, specifically inflammatory factors, by developing and implementing a bone-vascular microdevice platform that mimics the mineralized bone microenvironment. Aim 1 will determine optimal manufacturing conditions for producing a mineralized extracellular matrix (ECM) scaffold for osteoblast support in the microdevice. Aim 2 will develop the novel bone- vascular microdevice platform and investigate osteoblast-endothelial cell interactions under homeostatic conditions. Aim 3 will determine the effects of inflammatory cytokines interleukin-6, interleukin-1β, and interferon- γ on osteoblast-endothelial paracrine signaling using the microdevice platform. We will accomplish these aims by leveraging traditional ECM scaffold fabrication techniques with passive mineral deposition, computational fluid dynamics modeling of fluidic shear and nutrient transport, and biological assays of osteoblast activity and vascular barrier function. This work will create a new in vitro platform that enables mechanistic probing of complex bone-vascular interactions and advance understanding of inflammatory regulation of bone loss post- stroke, thereby providing a framework that may inform better treatment strategies to mitigate stroke-related bone fragility.