Liver transplantation continues to stand as the definitive clinical solution for patients suffering from end-stage liver disease. However, advancing our understanding of transplant biology, particularly the immune mechanisms underlying graft rejection and the pathways central to tissue repair and regeneration, has been severely constrained by the absence of physiologically precise human model systems. Traditional cell cultures and animal models fall short in replicating the liver’s complex multicellular architecture, its sophisticated vasculature network, and the dynamic immunological milieu that governs transplant fate, presenting a formidable barrier to translational progress.

Addressing these formidable challenges, the research team developed a liver tissueoid from donor-matched human hepatic progenitor cells in conjunction with intrahepatic portal vein endothelial cells. Cultured within a dynamic perfusion bioreactor, this co-culture self-organized into a perfusable microvascular network within merely one week. This initial vasculogenesis was succeeded by a progressive maturation stage extending over 49 days, culminating in a functional liver-mimetic tissueoid exhibiting salient features akin to native liver tissue.

Throughout long-term culture, the vascularized liver tissueoid demonstrated sustained viability and preserved endothelial integrity, as validated by advanced imaging and immunofluorescence methods. Functionally, the tissueoid exhibited hallmark hepatic activities — notably synthesizing albumin and urea at physiologically relevant levels, secreting key complement factors, and producing hepatocyte growth factor (HGF), a critical mediator of liver regeneration. These activities collectively confirmed the platform’s capacity to emulate native hepatic function over extended periods in vitro.

Beyond functional validation, comprehensive cellular phenotyping revealed that the mature tissueoid harbored a broad repertoire of liver-relevant cell populations. These included parenchymal hepatocytes, ductal cholangiocytes, resident macrophage-like Kupffer cells, fibrogenic stellate cells, and a robust endothelial network, replicating the cellular heterogeneity and spatial organization inherent to human liver tissue. This intricate multicellularity underpins the platform’s suitability for studying complex cell–cell and cell–immune system interactions central to transplant biology.

Crucially, the LToC system was employed to simulate immune-mediated allograft rejection by introducing allogeneic T cells into the perfused tissueoid. This immune challenge reproduced key features of acute cellular rejection: notable decline in overall tissue viability, disruption of the endothelial lining, and loss of hepatic lineage markers. Immunologically, there was an upregulation of HLA class I molecules and a surge in pro-inflammatory cytokines such as IL-6, TNF-α, IL-1β, and IFN-γ. Additionally, elevated levels of cytotoxic effector molecules—granzyme A, granzyme B, and perforin—were observed, mirroring the immunopathologic signature seen in clinical transplant rejection.

This integrative platform’s ability to model the interplay between hepatic tissue regeneration and immune activation marks a significant stride toward understanding the mechanistic basis for transplant outcomes in a human-specific context. According to Dr. Abdul Rahim Chethikkattuveli Salih, the first author on the study, “The liver tissueoid-on-a-chip enables us to recreate critical aspects of liver tissue regeneration and immune-mediated rejection with a level of complexity and physiological relevance not previously achievable.”

Dr. Vadim Jucaud, Principal Investigator and Assistant Professor, emphasized the system’s translational potential, remarking, “By integrating a rich vascular network, diverse liver cell populations, and robust immune responsiveness in a single microscale platform, our liver tissueoid-on-a-chip supports a deeper mechanistic study of transplant immunobiology. This approach opens exciting possibilities for preclinical evaluation of immunosuppressive therapies and the development of highly personalized treatment regimens for liver transplant patients.”

The innovation advances the legacy of Dr. Paul I. Terasaki, renowned for his monumental contributions to transplantation immunology. As one of Dr. Terasaki’s last doctoral mentees, Dr. Jucaud underscores the personal and professional significance of this work: “Dr. Terasaki’s vision that translational innovation must ultimately improve patient well-being guides our efforts. Our work bridges bioengineering, immunology, and regenerative medicine, moving toward practical solutions with tangible clinical impact.”

The liver tissueoid-on-a-chip platform reflects a broader paradigm shift in biomedical research that embraces sophisticated organotypic models to overcome the limitations of animal studies and simplistic cultures. By faithfully reproducing human tissue complexity and immune dynamics, this technology accelerates drug discovery, enhances mechanistic insights, and drastically reduces the translational gap between bench and bedside.

The Terasaki Institute continues its commitment to patient-centric innovation, advancing integrative technologies like the LToC platform that promise to revolutionize transplant medicine and liver disease treatment. By fostering interdisciplinary collaboration across engineering, immunology, and clinical science, the Institute aims to usher in a new era of personalized and precision medicine tailored to the unique immunological landscape and regenerative capacity of individual patients.

As the scientific community seeks to tackle the complexities of organ transplantation, the vascularized liver tissueoid-on-a-chip stands out as a pivotal tool for dissecting fundamental biological processes, evaluating novel therapeutics, and ultimately improving long-term transplant success rates and patient quality of life. This breakthrough epitomizes how cutting-edge tissue engineering intersects with immunology to reshape the future of regenerative medicine and transplantation biology.

Subject of Research: Human tissue samples

Article Title: Liver Tissueoid on-a-Chip Modeling Liver Regeneration and Allograft Rejection

News Publication Date: February 18, 2026

Web References: DOI: 10.1002/adma.202521178

Image Credits: Terasaki Institute for Biomedical Innovation

Keywords

Transplantation, Organ transplantation, Liver regeneration, Immunology, Biomedical engineering, Personalized medicine

The liver’s unique architecture is characterized by its metabolic zonation, where hepatocytes in distinct regions—the periportal (portal vein, PV) and pericentral (central vein, CV) zones—exhibit specialized functions directed by region-specific signaling pathways. Wnt/β-catenin signaling predominantly governs the pericentral region, while Notch signaling pathways drive periportal activities. These discrete signaling environments enable the liver to efficiently regulate complex metabolic, synthetic, and detoxification processes that are vital for systemic homeostasis.

Leveraging extensive transcriptomic analyses from both human and rodent liver tissues, the team meticulously mapped the spatial distribution of signaling pathways instrumental in liver zonation. This molecular blueprint revealed that genes associated with Wnt ligand WNT2 and Notch ligand DLL4 are expressed predominately in endothelial cells within their respective zones, forming the basis for generating engineered microenvironments. Confirmation through immunofluorescence and immunohistochemical studies on human liver sections validated these spatial patterns, providing a firm biological foundation to reconstruct zonal heterogeneity in vitro using genetically modified cell types.

Capitalizing on these insights, researchers developed two transgenic SK-Hep1 endothelial cell lines engineered to overexpress either WNT2 or DLL4. When co-cultured with primary human hepatocytes, these engineered endothelial cells orchestrated region-specific hepatocyte differentiation. The WNT2-expressing endothelial cells induced hepatocytes with enhanced cytochrome P450 enzyme activity, mimicking pericentral functions critical for xenobiotic metabolism. Conversely, DLL4-expressing cells promoted cholangiocyte-like phenotypes and enhanced bile transport characteristic of periportal zones, thereby recapitulating the spatial functional heterogeneity of the native liver.

The dynamic interplay within these organoids also enabled hepatic progenitor cells to bifurcate into hepatocyte- and cholangiocyte-dominant lineages, emulating the developmental plasticity governed by microenvironmental cues in the liver. This bifurcation is pivotal for generating organoids that not only function accurately but also reflect the liver’s developmental and regenerative biology, which has vast implications for modeling liver diseases and therapeutic interventions.

In pharmacological assays, the platform exhibited remarkable sensitivity and specificity. Upon exposure to acetaminophen, an established hepatotoxin, the WNT2 co-cultured organoids demonstrated heightened oxidative stress susceptibility coupled with a robust regenerative response upon drug withdrawal. Such findings mirror clinical hepatotoxicity and recovery patterns, positioning this organoid system as a superior model for drug-induced liver injury studies. Meanwhile, DLL4 co-cultured organoids effectively replicated cholestatic injury phenotypes, including impaired bile clearance following drug treatments, which were reversible upon administration of choleretic agents, showcasing its utility in modeling periportal pathologies.

Further pushing the envelope, the team harnessed state-of-the-art 3D bioprinting technology to spatially arrange endothelial and parenchymal cells into a biomimetic liver lobule architecture. This printed construct elegantly recapitulates the liver’s zonal organization, demonstrating region-specific expression of hallmark functional proteins such as glutamine synthetase in pericentral-mimicking zones and multidrug resistance protein 2 (MRP2) along with increased albumin and urea secretion. The 3D architecture closely mimics in vivo tissue ultrastructure and function, which is critical for accurate disease modeling and drug toxicity testing.

Intriguingly, the engineered lobule exhibited selective vulnerability akin to the native liver. The pericentral-mimicking zones showed heightened sensitivity to acetaminophen-induced injury, faithfully reproducing the hepatotoxic patterns observed clinically. This spatially resolved injury response highlights the model’s capacity to dissect zonal-specific pathophysiology, a feature that has been unattainable with conventional culture systems.

This breakthrough represents a significant leap in liver bioengineering by integrating gene-engineered endothelial microenvironment cues with sophisticated 3D bioprinting. The resultant platform stands out as a physiologically relevant, spatially complex system capable of emulating the liver’s functional heterogeneity and its nuanced injury responses. Its application promises to refine preclinical drug screening pipelines, enhancing prediction accuracy for hepatotoxicity and therapeutic efficacy.

Moreover, the platform opens avenues for personalized medicine in hepatology by enabling patient-specific modeling of liver diseases, including chronic liver conditions, metabolic disorders, and drug-induced liver injuries. Implementing such organoids in precision medicine could revolutionize how liver disease progression and treatment responses are studied and managed, reducing reliance on animal models and improving translational relevance.

The collaborative effort also emphasizes the critical role of endothelial heterogeneity in orchestrating liver function and regeneration, an often-overlooked aspect in traditional liver models. By recapitulating endothelial-mediated spatial signaling, this system affords a more faithful representation of the liver’s microenvironment, offering a valuable tool for studying vascular contributions to liver health and disease.

This pioneering work from Tsinghua University’s multidisciplinary team aligns with the cutting-edge trajectory of organoid technology, marrying genetic engineering, vascular biology, and bioprinting to recreate one of the body’s most metabolically complex organs. As such, it sets a new benchmark for organoid fidelity and functional sophistication, likely inspiring a paradigm shift in liver research methodologies.

Taken together, these innovations underscore the transformative potential of engineered organoids in research and medicine. Such platforms not only promise to expedite drug development by providing reliable human tissue surrogates but also have profound implications for regenerative therapies and the modeling of liver pathologies, ultimately propelling hepatology into a new era of precision biomedical sciences.

Subject of Research: Liver organoid development mimicking region-specific liver zonation for disease modeling and drug evaluation.

Article Title: Construction of Region-Specific Liver Organoid and Fabrication of Hierarchical Functional Liver Lobule for Liver Disease Modeling and Drug Evaluation.

Web References: http://dx.doi.org/10.1016/j.scib.2025.07.021

Image Credits: ©Science China Press

Keywords: liver organoid, metabolic zonation, Wnt signaling, Notch signaling, 3D bioprinting, hepatocyte differentiation, liver disease modeling, drug toxicity, liver microenvironment, endothelial heterogeneity, acetaminophen-induced injury, cholestasis.