Department of Chemical Engineering, Faculty of Engineering, Kyushu University, Nishi-ku, Fukuoka, Japan.
Cell Transplant. 2012;21(2-3):421-8. doi: 10.3727/096368911X605321.
Hybrid artificial liver (HAL) is an extracorporeal circulation system comprised of a bioreactor containing immobilized functional liver cells. It is expected to not only serve as a temporary liver function support system, but also to accelerate liver regeneration in recovery from hepatic failure. One of the most difficult problems in developing a hybrid artificial liver is obtaining an adequate cell source. In this study, we attempt to differentiate embryonic stem (ES) cells by hepatic lineage using a polyurethane foam (PUF)/spheroid culture in which the cultured cells spontaneously form spherical multicellular aggregates (spheroids) in the pores of the PUF. We also demonstrate the feasibility of the PUF-HAL system by comparing ES cells to primary hepatocytes in in vitro and ex vivo experiments. Mouse ES cells formed multicellular spheroids in the pores of PUF. ES cells expressed liver-specific functions (ammonia removal and albumin secretion) after treatment with the differentiation-promoting agent, sodium butyrate (SB). We designed a PUF-HAL module comprised of a cylindrical PUF block with many medium-flow capillaries for hepatic differentiation of ES cells. The PUF-HAL module cells expressed ammonia removal and albumin secretion functions after 2 weeks of SB culture. Because of high proliferative activity of ES cells and high cell density, the maximum expression level of albumin secretion function per unit volume of module was comparable to that seen in primary mouse hepatocyte culture. In the animal experiments with rats, the PUF-HAL differentiating ES cells appeared to partially contribute to recovery from liver failure. This outcome indicates that the PUF module containing differentiating ES cells may be a useful biocomponent of a hybrid artificial liver support system.
人-鼠嵌合型人工肝是一种体外循环系统，由包含固定化功能肝细胞的生物反应器组成。它不仅有望作为一种临时肝功能支持系统，还能促进肝功能衰竭恢复时的肝再生。开发人-鼠嵌合型人工肝最困难的问题之一是获得足够的细胞来源。在这项研究中，我们试图通过使用聚氨酯泡沫（PUF）/球体培养法使胚胎干细胞（ES 细胞）向肝系分化，在 PUF 的孔中培养的细胞会自发形成球形的多细胞聚集体（球体）。我们还通过体外和体内实验比较 ES 细胞和原代肝细胞，证明了 PUF-HAL 系统的可行性。小鼠 ES 细胞在 PUF 的孔中形成了多细胞球体。在用分化促进剂丁酸钠（SB）处理后，ES 细胞表达了肝特异性功能（氨清除和白蛋白分泌）。我们设计了一种由带有许多中流量毛细血管的圆柱形 PUF 块组成的 PUF-HAL 模块，用于 ES 细胞的肝分化。在 SB 培养 2 周后，PUF-HAL 模块细胞表达了氨清除和白蛋白分泌功能。由于 ES 细胞的高增殖活性和高细胞密度，模块每单位体积的白蛋白分泌功能的最大表达水平与原代小鼠肝细胞培养相当。在大鼠的动物实验中，PUF-HAL 分化的 ES 细胞似乎部分有助于肝功能衰竭的恢复。这一结果表明，含有分化 ES 细胞的 PUF 模块可能是一种有用的混合人工肝支持系统的生物成分。
