A Microfluidic Bone Marrow Niche for the Study of Hematopoiesis

描述（由申请人提供）：成人骨髓每天产生近5000亿个血细胞。每种血细胞都是生命所必需的：红细胞提供氧气，白色血细胞提供免疫力，血小板防止出血，以及这些细胞的其他功能。血细胞生成失调导致严重贫血、白细胞减少和血小板减少，并产生大量发病率和死亡率。在美国，每年大约输注1500万个红细胞单位、900万个血小板单位和数千个干细胞单位。然而，输注供体来源的血细胞引起了许多担忧，包括缺乏对质量和数量的控制，以及储存和输注期间感染和细菌污染的风险。刺激体内血小板生成或体外产生足够数量的血细胞的新策略将彻底改变贫血和血细胞减少症的管理。造血细胞培养的分子生物学和生物化学调控已经取得了重要进展。然而，这些方法受限于它们不能再现骨髓结构的复杂性。在这里，我们建议开发一种体外微流体骨髓生态位，它概括了骨髓的细胞和基质成分，但也可以被操纵，以确定每个组件在正常骨髓的功能中的作用，并允许我们阐明和控制造血。理想情况下，该系统将是可扩展的，最终目标是在体外产生用于输血的血细胞。尽管在过去的几十年里人们已经了解了有关造血机制的许多信息，但仍有很多未知之处，特别是关于特定骨髓龛在血细胞产生中的作用。组织工程学和血管生物学的最新进展使其成为解开这些谜团的最佳时机。微流体骨髓龛的创建将代表第一个体外系统，该系统重现了骨髓的复杂结构，并具有生成血细胞的功能。独特的是，该系统允许逐步添加或去除小生境的各个成分，以揭示它们在血细胞生产中的各自功能。拟议的工作不仅是理解和控制健康和疾病状态下造血发育的重要一步，而且还可以彻底改变临床前测试的疗法，以增加由于疾病本身或其治疗而导致的低血细胞计数的疾病。该系统还将允许优化用于血细胞的离体生产的条件。一旦确定了这些条件，该系统就可以按比例扩大，以产生足够的输血量。

DESCRIPTION (provided by applicant): The bone marrow produces nearly 500 billion blood cells per day in an adult human. Each type of blood cell is required for life: red blood cells deliver oxygen, white blood cells provide immunity, and platelets prevent bleeding, among other functions of these cells. Dysregulation of blood cell production leads to severe anemia, leukopenia, and thrombocytopenia, and produces substantial morbidity and mortality. Approximately 15 million red blood cell units, 9 million platelet units and thousands of stem cell units are transfused annually in the United States. Transfusion of donor-derived blood cells, however, raises many concerns, including the lack of control over quality and quantity, and the risk of infectious and bacterial contamination during storage and transfusion. New strategies to stimulate thrombopoiesis in vivo, or to produce sufficient numbers of blood cells in vitro would revolutionize the management of anemia and cytopenias. Important progress has been made towards tailoring the molecular biology and biochemical regulation of hematopoietic cells in culture. These approaches, however, are limited by their failure to reproduce the complexity of bone marrow architecture. Here we propose to develop an in vitro microfluidic bone marrow niche that recapitulates the bone marrow in its cellular and matrix components, but which can also be manipulated to determine the roles of each component in the functioning of a normal bone marrow, and allow us to elucidate and control hematopoiesis. Ideally, this system will be scalable, with the ultimate goal of generating blood cells in vitro for transfusion. Although much information has been learned about the mechanisms of hematopoiesis over the last several decades, a great deal remains unknown, particularly regarding the role of specific marrow niches in blood cell production. Recent advances in tissue engineering and vascular biology make it an opportune time to unravel these mysteries. The creation of the microfluidic bone marrow niche will represent the first in vitro system that recapitulates the complex architecture of the bone marrow, and functions to generate blood cells. Uniquely, this system allows the stepwise addition or removal of individual components of the niche to reveal their individual functions in blood cell production. The proposed work will not only be an important step towards understanding and controlling the hematopoietic development in both healthy and diseased states, but could also revolutionize preclinical testing for therapies to increase blood cell count in diseases where they are low, either because of the disease itself or its therapy. This system will also allow for optimization of the conditions for ex vivo production of blood cells. Once thes conditions are determined, the system can be scaled up to generate quantities sufficient for transfusion.