Lu Ting-Yu, Ji Yichun, Lyu Cheng, Shen Erin Nicole, Sun Yazhi, Xiang Yi, Meng-Saccoccio Tobias, Feng Gen-Sheng, Chen Shaochen
Program in Materials Science and Engineering, University of California San Diego, La Jolla, CA, 92093, USA.
Department of Pathology, Department of Molecular Biology, Moores Cancer Center, University of California San Diego, La Jolla, CA, 92093, USA.
Biomaterials. 2025 Sep;320:123256. doi: 10.1016/j.biomaterials.2025.123256. Epub 2025 Mar 11.
In vitro liver tissue models are valuable for studying liver function, understanding liver diseases, and screening candidate drugs for toxicity and efficacy. While three-dimensional (3D) bioprinting shows promise in creating various types of functional tissues, current efforts to engineer a functional liver tissue face challenges in replicating native high cell density (HCD) and maintaining long-term cell viability. HCD is crucial for establishing the cell-cell interactions necessary to mimic the liver's metabolic and detoxification functions. However, HCD bioinks exacerbate light scattering in light-based 3D bioprinting. In this study, we incorporated iodixanol into our bioink formulation to minimize light scattering, enabling the fabrication of hepatic tissue constructs with an HCD of 8 × 10 cells/mL while maintaining high cell viability (∼80 %). The printed dense hepatic tissue constructs showed enhanced cell-cell interactions, as evidenced by increased expression of E-cadherin and ZO-1. Furthermore, these constructs promoted albumin secretion, urea production, and P450 metabolic activity. Additionally, HCD hepatic tissue inactivated the YAP/TAZ pathway via cell-cell interactions, preserving primary hepatocyte functions. Further screening revealed that hepatocytes in the dense model were more sensitive to drug treatments than those in a lower-density hepatic model, highlighting the importance of HCD in recapitulating the physiological drug responses. Overall, our approach represents a significant advancement in liver tissue engineering, providing a promising platform for the development of physiologically relevant in vitro liver models for drug screening and toxicity testing.
体外肝组织模型对于研究肝功能、理解肝脏疾病以及筛选候选药物的毒性和疗效具有重要价值。虽然三维（3D）生物打印在创建各种类型的功能组织方面显示出前景，但目前构建功能性肝组织的努力在复制天然高细胞密度（HCD）和维持长期细胞活力方面面临挑战。HCD对于建立模拟肝脏代谢和解毒功能所需的细胞间相互作用至关重要。然而，HCD生物墨水会加剧基于光的3D生物打印中的光散射。在本研究中，我们将碘克沙醇加入生物墨水配方中以最小化光散射，从而能够制造出细胞密度为8×10⁶细胞/mL的肝组织构建体，同时保持高细胞活力（约80%）。打印出的致密肝组织构建体显示出增强的细胞间相互作用，E - 钙黏蛋白和紧密连接蛋白1（ZO - 1）表达增加证明了这一点。此外，这些构建体促进了白蛋白分泌、尿素生成和细胞色素P450代谢活性。此外，HCD肝组织通过细胞间相互作用使Yes相关蛋白（YAP）/转录激活子TAZ（TAZ）信号通路失活，从而保留原代肝细胞功能。进一步筛选发现，致密模型中的肝细胞比低密度肝模型中的肝细胞对药物治疗更敏感，突出了HCD在重现生理药物反应方面的重要性。总体而言，我们的方法代表了肝组织工程的重大进展，为开发用于药物筛选和毒性测试的生理相关体外肝模型提供了一个有前景的平台。
