Department of Bioengineering, Henry Samueli School of Engineering and Applied Sciences, University of California-Los Angeles, Los Angeles, CA, 90095, USA.
Center for Minimally Invasive Therapeutics (C-MIT), University of California-Los Angeles, Los Angeles, CA, 90095, USA.
Adv Healthc Mater. 2019 Dec;8(24):e1901379. doi: 10.1002/adhm.201901379. Epub 2019 Nov 20.
The liver has a complex and unique microenvironment with multiple cell-cell interactions and internal vascular networks. Although nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease with multiple phases, no proper model could fully recapitulate the in vivo microenvironment to understand NAFLD progression. Here, an in vitro human liver model of NAFLD by coculturing human hepatocytes, umbilical vein endothelial cells (HUVECs), and Kupffer cells (KCs) into spheroids is presented. Analysis of indirect cross-talk using conditioned media between steatotic spheroids-composed of hepatocellular carcinoma-derived cells (HepG2) and HUVECs-and mouse KCs reveals that the latter can be activated showing increased cell area, elevated production of reactive oxygen species (ROS), and proinflammatory cytokines. Spheroids incorporating human KCs (HKCs) can also be induced into steatotic stage by supplementing fat. Steatotic spheroids with/without HKCs show different levels of steatotic stages through lipid accumulation and ROS production. Steatotic spheroids made from an immortalized hepatic progenitor cell line (HepaRG) compared to those made from HepG2 cells display similar trends of functionality, but elevated levels of proinflammatory cytokines, and improved reversibility of steatosis. The in vitro human liver system proposed makes strides in developing a model to mimic and monitor the progression of NAFLD.
肝脏具有复杂而独特的微环境，其中包含多种细胞-细胞相互作用和内部血管网络。尽管非酒精性脂肪性肝病 (NAFLD) 是最常见的具有多个阶段的慢性肝病，但没有合适的模型能够完全再现体内微环境以了解 NAFLD 的进展。在这里，通过将人原代肝细胞、脐静脉内皮细胞 (HUVEC) 和库普弗细胞 (KCs) 共培养成球体，提出了一种体外 NAFLD 人肝模型。通过分析由肝癌来源细胞 (HepG2) 和 HUVEC 组成的脂肪变性球体与小鼠 KCs 之间的条件培养基的间接串扰，揭示后者可以被激活，表现为细胞面积增加、活性氧 (ROS) 产生增加和促炎细胞因子产生增加。用人 KCs (HKCs) 掺入的球体也可以通过补充脂肪诱导进入脂肪变性阶段。含有/不含有 HKCs 的脂肪变性球体通过脂质积累和 ROS 产生显示出不同的脂肪变性阶段水平。与 HepG2 细胞相比，源自永生化肝祖细胞系 (HepaRG) 的脂肪变性球体显示出相似的功能趋势，但促炎细胞因子水平升高，脂肪变性的可逆性提高。所提出的体外人肝系统在开发模拟和监测 NAFLD 进展的模型方面取得了进展。
