A perfusable human liver-on-a-chip platform for modeling non-alcoholic hepatic steatosis and drug testing

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world, and establishing a reliable disease model will help to study its pathogenesis and drug screening. As a kind of burgeoning liver model in vitro, liver-on-a-chip system with higher physiological correlation has been extensively used in disease modeling, drug testing and toxicity evaluation. Our study was designed to present a new perfusable human liver-on-a-chip platform for the construction of functional liver tissue and successfully modeling NAFLD. Finally, the NAFLD-on-a-chip model was verified the capability for evaluating drug testing upon NAFLD. A liver-on-a-chip platform was constructed in a microfluidic chip by coculturing hepatocellular carcinoma-derived cells (HepG2), umbilical vein endothelial cells (HUVECs), and hepatic stellate cells (LX2) into hepatic spheroids in the cylindrical cavity array. Tight junction protein ZO-1, endothelial cell marker CD31 and liver function proteins albumin and CYP3A4 were detected to verify the tissue structure integrity and physiological activity of liver function from the hepatic spheroids. A free fatty acids (FFAs) mixture was introduced into the liver-on-a-chip to induce an NAFLD model. Then three potential drugs, including ezetimibe (Eze), metformin (Met), and pioglitazone (Pio) were used to validate the application potential of the NAFLD-on-a-chip for the treatment of hepatic steatosis. Hepatic parenchymal and non-parenchymal cells cocultured in liver-on-a-chip platform could produce hepatic spheroids with controllable morphology, as well as the CYP450 expression and albumin secretion. Based on this platform, a NAFLD-on-a-chip model was successfully established by exposing the liver-on-a-chip to a lipotoxic environment. Finally, to verify the effectiveness of the NAFLD-on-a-chip platform, we validated the inhibitory effect of three potential drugs on NAFLD. Conclusions: This study provides a viable and valuable in vitro platform for understanding the progression and drug evaluation of NAFLD. • A new perfusable human liver-on-a-chip platform was constructed in a microfluidic chip by coculturing HepG2, HUVECs, and LX2. • The hepatic spheroids cultured on the designed chip could maintain high level of physiological activity in liver function. • An NAFLD model was simulated by introduce a FFAs mixture of oleic acid (OA) and palmitic acid (PA) into the liver-on-a-chip. • The NAFLD-on-a-chip model presented potential application in drug evaluation for NAFLD treatment.