A Microfluidic Bone Marrow Niche for the Study of Hematopoiesis

描述(申请人提供)：一个成年人的骨髓每天产生近5000亿个血细胞。每种类型的血细胞都是生命所必需的：红细胞提供氧气，白细胞提供免疫力，血小板防止出血，以及这些细胞的其他功能。血细胞生产的失调会导致严重的贫血、白细胞减少和血小板减少，并导致相当大的发病率和死亡率。在美国，每年大约有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被输注。然而，输注捐献者来源的血细胞引起了许多关切，包括缺乏对质量和数量的控制，以及在储存和输血过程中存在感染和细菌污染的风险。在体内刺激血栓生成或在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治疗方法。在培养造血细胞的分子生物学和生化调控方面取得了重要进展。然而，这些方法由于未能再现骨髓结构的复杂性而受到限制。在这里，我们建议开发一个体外微流控骨髓生态位，它概括了骨髓的细胞和基质成分，但也可以被操纵来确定每个成分在正常骨髓功能中的作用，并使我们能够阐明和控制造血。理想情况下，这个系统是可扩展的，最终目标是在体外产生供输血用的血细胞。尽管在过去的几十年里，人们已经了解了许多关于造血机制的信息，但仍有许多信息尚不清楚，特别是关于特定的骨髓壁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得现在是揭开这些谜团的好时机。微流控骨髓壁龛的创建将代表第一个重述骨髓复杂结构并具有生成血细胞功能的体外系统。独一无二的是，这个系统允许逐步添加或移除利基的个别成分，以揭示它们在血细胞生产中的单独功能。这项拟议的工作不仅将是了解和控制健康和疾病状态下的造血发展的重要一步，而且还可能彻底改变治疗的临床前测试，以增加由于疾病本身或其治疗而导致的疾病的血细胞计数。该系统还将允许优化体外生产血细胞的条件。一旦确定了这些条件，系统就可以扩大规模，产生足够输血的数量。

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.