Liver sinusoid

Abstract: Physiologically, four major types of hepatic cells – the liver sinusoidal endothelial cells, Kupffer cells, hepatic stellate cells, and hepatocytes – reside inside liver sinusoids and interact with flowing peripheral cells under blood flow. It is hard to mimic an in vivo liver sinusoid due to its complex multiple cell–cell interactions, spatiotemporal construction, and mechanical microenvironment. Here we developed an in vitro liver sinusoid chip by integrating the four types of primary murine hepatic cells into two adjacent fluid channels separated by a porous permeable membrane, replicating liver's key structures and configurations. Each type of cells was identified with its respective markers, and the assembled chip presented the liver-specific unique morphology of fenestration. The flow field in the liver chip was quantitatively analyzed by computational fluid dynamics simulations and particle tracking visualization tests. Intriguingly, co-culture and shear flow enhance albumin secretion independently or cooperatively, while shear flow alone enhances HGF production and CYP450 metabolism. Under lipopolysaccharide (LPS) stimulations, the hepatic cell co-culture facilitated neutrophil recruitment in the liver chip. Thus, this 3D-configured in vitro liver chip integrates the two key factors of shear flow and the four types of primary hepatic cells to replicate key structures, hepatic functions, and primary immune responses and provides a new in vitro model to investigate the short-duration hepatic cellular interactions under a microenvironment mimicking the physiology of a liver.

Abstract: The development of long-term human organotypic liver-on-a-chip models for successful prediction of toxic response is one of the most important and urgent goals of the NIH/DARPA's initiative to replicate and replace chronic and acute drug testing in animals. For this purpose, we developed a microfluidic chip that consists of two microfluidic chambers separated by a porous membrane. The aim of this communication is to demonstrate the recapitulation of a liver sinusoid-on-a-chip, using human cells only for a period of 28 days. Using a step-by-step method for building a 3D microtissue on-a-chip, we demonstrate that an organotypic in vitro model that reassembles the liver sinusoid microarchitecture can be maintained successfully for a period of 28 days. In addition, higher albumin synthesis (synthetic) and urea excretion (detoxification) were observed under flow compared to static cultures. This human liver-on-a-chip should be further evaluated in drug-related studies.

Abstract: We describe the generation of microfluidic platforms for the co-culture of primary hepatocytes and endothelial cells; these platforms mimic the architecture of a liver sinusoid. This paper describes a progressional study of creating such a liver sinusoid on a chip system. Primary rat hepatocytes (PRHs) were co-cultured with primary or established endothelial cells in layers in single and dual microchannel configurations with or without continuous perfusion. Cell viability and maintenance of hepatocyte functions were monitored and compared for diverse experimental conditions. When primary rat hepatocytes were co-cultured with immortalized bovine aortic endothelial cells (BAECs) in a dual microchannel with continuous perfusion, hepatocytes maintained their normal morphology and continued to produce urea for at least 30 days. In order to demonstrate the utility of our microfluidic liver sinusoid platform, we also performed an analysis of viral replication for the hepatotropic hepatitis B virus (HBV). HBV replication, as measured by the presence of cell-secreted HBV DNA, was successfully detected. We believe that our liver model closely mimics the in vivo liver sinusoid and supports long-term primary liver cell culture. This liver model could be extended to diverse liver biology studies and liver-related disease research such as drug induced liver toxicology, cancer research, and analysis of pathological effects and replication strategies of various hepatotropic infectious agents. .