血管化是所有复杂器官组织工程体外构筑成败的瓶颈。肝窦内皮细胞(LSEC)构成的肝血窦不仅向肝细胞索提供营养物质与氧气，还分泌多种细胞因子形成特殊血管微环境，控制肝组织的发育、稳态维持和修复再生。实现组织工程肝脏血管化需要解决2个关键问题：LSEC和肝系细胞如何相互调控达到重建组织稳态？新生血管如何调控肝组织结构重建和功能再生？申请者前期已成功建立脱细胞肝脏生物支架策略和再细胞化构建组织工程肝脏的技术体系，并证明特定酶修饰的硫酸乙酰肝素蛋白聚糖(HSPG)对肝窦内皮细胞具有高度亲和力和促进血管化及抗凝血功能。本项目中我们提出并验证假说“HSPG作为时空变阻器引导功能性血管化，通过Ang2-VEGFR2通路调控LSEC和肝系细胞反馈环路促进肝组织重塑”，并应用该原理指导我们将干细胞生物学、糖生物学、材料学与肝脏仿生构筑相结合，开展再细胞化再血管化和具有高度抗凝活性的仿生肝组织构建及其机制研究。

Vascularization is the bottleneck of complex organ tissue engineering construction in vitro. Hepatic sinusoids not only provide nutrients and oxygen to the hepatocytes along the liver cords, which closely neighbored to the liver sinusoidal endothelia cells (LSECs), also formed a special vascular microenvironment by secreting a variety of cytokines, which regulate liver tissue development, homeostasis maintenance and liver regeneration after injury. There are two major key issues need to be addressed to realize vascularization of tissue engineered liver: how the LSECs and hepatocytes mutually regulate each other to reconstruct the tissue homeostasis? How the neogenerated sinusoids control the structure reconstruction and functional regeneration of the engineered liver tissue? The applicant has successfully established the strategies of preparing acellular liver biomatrix scaffold and the technology system of recellularization of the scaffold for liver tissue engineering. Moreover, our studies demonstrated that specific enzymatic modified heparan sulfate proteoglycan (HSPG) showed high affinity to LSECs and could promote angiogenesis and anti-coagulation function. In this project we propose and will validate the hypothesis that “HSPG as a spatiotemporal rheostat that guides functional vascularization and promotes liver tissue remodeling by regulation of LSECs mediated by Ang2-VEGFR2 signaling pathway”. Finally, that principle will guide us to carry out multidisciplinary research involved of stem cell biology, glycobiology, biomaterial science and bionic architecture, to understand and construct of recellularized, revascularized biomimetic liver tissue with highly anticoagulant activity.