Primary sclerosing cholangitis (PSC) presents one of the most challenging clinical puzzles in hepatology, defined by chronic inflammation and progressive fibrosis of the bile ducts that eventually lead to obstructive cholestasis and liver failure. This rare, non-communicable disease is marked by the insidious development of fibrotic strictures within both intrahepatic and extrahepatic bile ducts, culminating in bile retention, which inflicts toxic damage upon hepatic tissue. In its advanced stages, PSC often mandates liver transplantation as the sole viable therapeutic recourse. The intricate pathogenesis involves not only biliary epithelial cells but a complex interplay of immune dysregulation, microbial factors, and genetic predispositions, making PSC a multifactorial disorder that has historically been difficult to model and study effectively.
A landmark review recently published in the journal Portal Hypertension & Cirrhosis comprehensively evaluates the spectrum of experimental systems devised to emulate PSC’s pathological landscape. Led by Professor Hongcui Cao from Zhejiang University School of Medicine, this rigorous synthesis of the current literature investigates the capabilities and limitations of existing animal models, traditional cell culture systems, three-dimensional organoids, and cutting-edge bioengineered constructs. Prof. Cao emphasizes that a nuanced understanding of these models is pivotal to accelerating translational research and the development of novel therapies, given PSC’s complex physiology and clinical heterogeneity.
Mice have emerged as indispensable tools in dissecting the cellular and molecular underpinnings of PSC. Genetic engineering has enabled the creation of specific knockout models, such as the Mdr2 (multidrug resistance-related protein 2) knockout mouse, which recapitulates bile acid accumulation and subsequent cholangiopathy. Similarly, Cftr (cystic fibrosis transmembrane conductance regulator) knockout mice exhibit cholangiocyte dysfunction linked to defective chloride ion transport, mirroring aspects of biliary disease pathology. Complementing these genetic approaches are chemically induced models using agents like α-naphthalene isothiocyanate (ANIT) and 2,4,6-trinitrobenzene sulfonic acid (TNBS), which induce cholangitis and mimic inflammatory dysregulation. These in vivo platforms furnish invaluable insights into bile acid toxicity, ductular reaction, and fibrogenesis, providing mechanistic clarity on disease initiation and progression.
However, these mouse models are not without critical drawbacks. Chief among these is the absence of concomitant intestinal inflammation evident in human PSC, reflecting its tight association with inflammatory bowel disease (IBD). This disjunction limits the translational fidelity of murine models, as does the variable extent of extrahepatic manifestations. Furthermore, gene knockouts frequently provoke off-target effects impacting other organs, clouding interpretation. Chronic administration of hepatotoxic compounds, while useful, restricts the modeling timeframe due to systemic toxicity, thereby complicating longitudinal studies. Ultimately, the murine immune system diverges in key molecular signaling axes from humans, underscoring the necessity for complementary human-specific models.
Primary human hepatic cholangiocytes (PHCs) stand as foundational in vitro cellular systems to investigate PSC pathophysiology. Yet, traditional two-dimensional cultures of PHCs suffer intrinsic limitations. The loss of three-dimensional spatial architecture and cell-cell as well as cell-matrix interactions compromises physiological relevance, weakening their utility in fully representing the dynamic biliary microenvironment and fibrotic remodeling observed in vivo. This shortfall invariably restricts mechanistic studies and drug testing to a simplistic biochemical context, excluding complex multicellular interplay and biomechanical cues important in PSC.
The advent of organoid technology has revolutionized PSC modeling by overcoming the dimensional and interactive constraints of planar cultures. Organoids constitute self-organizing, three-dimensional cellular aggregates that recapitulate tissue microanatomy and function. In PSC research, cholangiocyte-derived organoids and liver organoids generated from induced pluripotent stem cells (iPSCs) provide sophisticated platforms capable of modeling bile duct epithelia and liver parenchyma, respectively. These organoids emulate aspects of biliary tissue morphology and enable longitudinal studies of cellular responses to bile acid stress, immune effectors, and fibrogenic signals within a controlled environment. Moreover, these systems facilitate personalized medicine approaches by incorporating patient-derived cells.
Expanding upon these biological systems, bioengineering methodologies have propelled organoid research into new dimensions of complexity and applicability. Scientists have fabricated bioengineered bile ducts employing biomaterials that mimic the extracellular matrix, ensuring mechanical integrity while supporting cell viability and differentiation. More ambitiously, “liver-on-a-chip” microfluidic devices integrate multiple cell types, perfusion systems, and sensor technologies, allowing real-time assessment of hepatobiliary function and drug responses with exquisite precision. This convergence of tissue engineering and microfabrication has ushered in scalable platforms for rapid drug screening and preclinical evaluation of PSC therapeutics, marking a transformative stride in the field.
Bioengineered organoids also hold immense promise in regenerative medicine. Transplantation of healthy organoids derived from cholangiocytes or iPSCs has demonstrated potential for repairing damaged biliary epithelium in preclinical models. This therapeutic paradigm could ameliorate PSC pathology by restoring ductal integrity and normalizing bile flow, potentially delaying or obviating the need for liver transplantation. Nonetheless, challenges remain in achieving full vascularization, immune compatibility, and integration within the complex hepatic niche. Addressing these hurdles is paramount for clinical translation.
Looking towards the horizon, Prof. Cao is optimistic that the iterative refinement of animal and organoid models will synergistically advance our understanding of PSC. Mouse models will continue to elucidate the biomechanical and inflammatory cascades driving fibrosis, while organoid and bioengineered systems promise unparalleled insights into human-specific disease mechanisms, enabling precision drug screening and immunomodulatory strategies. Ongoing research into optimizing culture conditions, integrating immune components, and replicating vascular supply within organoids is critical to surmount existing limitations and broaden model applicability.
The broader implications of these advancements extend beyond PSC to numerous rare and complex hepatic diseases characterized by fibrotic and inflammatory etiologies. The establishment of robust, physiologically relevant in vitro and in vivo models catalyzes not only therapeutic innovation but also the fundamental biology of cholangiopathies. As research converges on elucidating cellular crosstalk, signaling networks, and genetic susceptibility, the potential for breakthrough treatments grows exponentially, offering renewed hope for patients afflicted by this enigmatic disease.
The review by Professor Hongcui Cao and colleagues thus stands as a pivotal resource consolidating the fragmented landscape of PSC models. It delineates the current strengths of each system while candidly addressing their shortcomings, advocating for strategic integration of diverse methodologies. This integrative approach, leveraging genetic models, organoids, and bioengineering, embodies the frontier of hepatobiliary research, poised to reshape diagnostic and therapeutic paradigms in PSC and beyond.
In conclusion, the evolution of PSC research models—from traditional knockout mice to advanced bioengineered organoids—highlights the fusion of multidisciplinary sciences aimed at conquering complex liver diseases. As the field pushes forward, collaboration between molecular biologists, clinicians, bioengineers, and computational scientists will be essential. This will foster the translation of experimental findings into tangible clinical outcomes, ultimately improving prognoses and quality of life for individuals battling primary sclerosing cholangitis.
Subject of Research: Human tissue samples
Article Title: Current Cell/Organoid and Animal Models for Primary Sclerosing Cholangitis
News Publication Date: 5-May-2026
References: DOI: 10.1002/poh2.70048 [http://dx.doi.org/10.1002/poh2.70048]
Image Credits: Hongcui Cao from Zhejiang University School of Medicine, China
Keywords: Primary sclerosing cholangitis, PSC, bile duct fibrosis, liver disease models, organoids, bioengineering, cholangiocytes, animal models, liver-on-a-chip, regenerative medicine, cholangiopathy, hepatology
