Human Vascularized Bile Duct-on-a Chip: A multi-cellular micro-physiological system for studying Primary Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease in which the bile ducts of the liver become inflamed and scarred. Scarred bile ducts eventually narrow and obstruct and can cause additional liver pathology including liver failure, repeated infections, and tumors. The pathogenesis of PSC remains largely unknown, partly due to difficulty in obtaining cholangiocytes and partly due to a paucity of in vitro models that capture the various factors contributing to disease progression. Here we report the development of a human vascularized bile duct-on-a-chip that models blood vessels and bile ducts structurally and functionally in three dimensions and includes cholangiocytes derived from control and PSC patient tissue and bile. The flow of blood and bile was modeled by perfusion of cell-lined channels, and cholangiocytes and endothelial cells displayed differential responses to perfusion. Normal and PSC cholangiocytes polarized normally, formed mature tight junctions and displayed similar permeability, comparable to ex vivo measurements. The model with PSC cholangiocytes, however, became more inflammatory than the normal under the stimulation of IL-17A, which induced PBMC and differentiated Th17 cells in the vascular channel to transmigrate more through the endothelial layer of the vascular compartment. In sum, this human vascularized bile duct-on-a-chip recapitulated the vascular-biliary interface structurally and functionally and represents a novel multicellular platform to study inflammatory and fibrotic cholangiopathies such as PSC. ### Competing Interest Statement The authors have declared no competing interest. * PSC : primary sclerosing cholangitis VBDOC : vascularized bile duct-on-a-chip CCCM : complete cholangiocyte culture medium EGM : endothelial growth medium HUVEC : human umbilical vein endothelial cell ECM : extracellular matrix PDMS : polydimethylsiloxane FITC : fluorescein isothiocyanate PBS : phosphate buffered saline Pd : permeability coefficient PFA : paraformaldehyde BSA : bovine serum albumin DAPI : 4′,6-diamidino-2-phenylindole ZO-1 : zona occludens 1 ASBT : apical sodium-dependent bile salt transporter CFTR : cystic fibrosis transmembrane conductance regulator SCTR : secretin receptor ICAM-1 : intercellular cell adhesion molecule-1 VCAM-1 : vascular cell adhesion molecule-1 LPS : Lipopolysaccharide PBMC : peripheral blood mononuclear cell