A number of cell culture approaches have been described for maintenance of primary hepatocytes. Forming hepatocytes into 3D spheroids is one well accepted method for extending epithelial phenotype of these cells. Our lab has previously observed enhanced function of 2D (monolayer) hepatocyte cultures in microfluidic devices due to increased production of several hepato-inductive growth factors, including hepatocyte growth factor (HGF). In the present study we wanted to test a hypothesis that placing hepatocytes spheroids (3D) into microfluidic devices will also result in enhanced phenotype and function. To test this hypothesis, we fabricated devices with small and large volumes. Both types of devices included a microstructured floor containing arrays of pyramidal wells to promote assembly of single hepatocytes into spheroids with individual diameter of ~100 µm. The hepatocyte spheroids were found to be more functional in low volume compared to large volume devices. Importantly, high functionality of spheroid cultures correlated with elevated levels of HGF secretion. While decay of hepatic function (albumin secretion) was observed over the course three weeks, this behavior could be abrogated by inhibiting TGF-β1 signaling. With TGF-β1 inhibitor, microfluidic hepatocyte spheroid cultures maintained high and stable levels of albumin synthesis over the course of four weeks. To further highlight utility of this culture platform for liver disease modeling, we carried out alcohol injury experiments in microfluidic devices and tested protective effects of interleukin (IL)-22 - a potential therapy for alcoholic hepatitis.

中文翻译：

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微流体限制增强了肝细胞球体的表型和功能。

已经描述了许多用于维持原代肝细胞的细胞培养方法。将肝细胞形成 3D 球体是一种广为接受的用于扩展这些细胞的上皮表型的方法。我们的实验室之前观察到，由于包括肝细胞生长因子 (HGF) 在内的几种肝诱导生长因子的产量增加，微流体装置中二维（单层）肝细胞培养物的功能增强。在本研究中，我们想要检验将肝细胞球体 (3D) 放入微流体装置中也会导致表型和功能增强的假设。为了检验这个假设，我们制造了体积小和体积大的设备。这两种类型的设备都包括一个微结构底板，其中包含锥体孔阵列，以促进单个肝细胞组装成单个直径约为 100 µm 的球状体。与大容量装置相比，肝细胞球体在低容量下的功能更强。重要的是，球体培养物的高功能与 HGF 分泌水平升高相关。虽然在三周的过​​程中观察到了肝功能（白蛋白分泌）的衰退，但这种行为可以通过抑制 TGF-β1 信号传导来消除。在使用 TGF-β1 抑制剂的情况下，微流体肝细胞球体培养物在 4 周内保持了高水平且稳定的白蛋白合成。为了进一步突出该培养平台在肝病建模中的效用，