Department of Internal Medicine, Nihon University School of Medicine, 30-1 Oyaguchikamicho, Itabashi-ku, Tokyo 173-8610, Japan.
Exp Biol Med (Maywood). 2011 Nov;236(11):1342-50. doi: 10.1258/ebm.2011.011075. Epub 2011 Oct 20.
Hematopoiesis occurs in the bone marrow, where primitive hematopoietic cells proliferate and differentiate in close association with a three-dimensional (3D) hematopoietic microenvironment composed of stromal cells. We examined the hematopoietic supportive ability of stromal cells in a 3D culture system using polymer particles with grafted epoxy polymer chains. Umbilical cord blood-derived CD34(+) cells were co-cultivated with MS-5 stromal cells. They formed a 3D structure in the culture dish in the presence of particles, and the total numbers of cells and the numbers of hematopoietic progenitor cells, including colony-forming unit (CFU)-Mix, CFU-granulocyte-macrophage, CFU-megakaryocyte and burst-forming unit-erythroid, were measured every seven days. The hematopoietic supportive activity of the 3D culture containing polymer particles and stromal cells was superior to that of 2D culture, and allowed the expansion and maintenance of hematopoietic progenitor cells for more than 12 weeks. Various types of hematopoietic cells, including granulocytes, macrophages and megakaryocytes at different maturation stages, appeared in the 3D culture, suggesting that the CD34(+) cells were able to differentiate into a range of blood cell types. Morphological examination showed that MS-5 stromal cells grew on the surface of the particles and bridged the gaps between them to form a 3D structure. Hematopoietic cells slipped into the 3D layer and proliferated within it, relying on the presence of the MS-5 cells. These results suggest that this 3D culture system using polymer particles reproduced the hematopoietic phenomenon in vitro, and might thus provide a new tool for investigating hematopoietic stem cell-stromal cell interactions.
造血发生在骨髓中，原始造血细胞在这里与由基质细胞组成的三维（3D）造血微环境密切相关而增殖和分化。我们使用接枝有环氧聚合物链的聚合物颗粒在 3D 培养系统中检查基质细胞的造血支持能力。将脐带血来源的 CD34(+)细胞与 MS-5 基质细胞共培养。在颗粒存在的情况下，它们在培养皿中形成 3D 结构，并且每隔七天测量细胞总数和造血祖细胞的数量，包括集落形成单位（CFU）-Mix、CFU-粒细胞-巨噬细胞、CFU-巨核细胞和爆式形成单位-红细胞。含有聚合物颗粒和基质细胞的 3D 培养的造血支持活性优于 2D 培养，并且允许造血祖细胞的扩增和维持超过 12 周。在 3D 培养中出现了各种类型的造血细胞，包括不同成熟阶段的粒细胞、巨噬细胞和巨核细胞，这表明 CD34(+)细胞能够分化为多种类型的血细胞。形态学检查显示 MS-5 基质细胞在颗粒表面生长并桥接它们之间的间隙以形成 3D 结构。造血细胞滑入 3D 层并在其中增殖，依赖于 MS-5 细胞的存在。这些结果表明，这种使用聚合物颗粒的 3D 培养系统在体外再现了造血现象，并且可能因此为研究造血干细胞-基质细胞相互作用提供了一种新工具。
