Arificial biliary duct model for surgical therapeutic material and research material for biliary cancer

人工胆管可作为外科材料，用于研究胆道癌等胆道疾病的病理和治疗机制。我们重建了由胆管上皮单层和结缔组织亚层组成的三维人工胆管。我们首先使用由心轴和鞘组成的管状玻璃模具制备了由人成纤维细胞和胶原凝胶组成的管状结构组织。然后，通过种植人胆管上皮细胞和肾小管组织，构建具有层次化结构的杂交组织。我们之前制作的人工胆管的最大尺寸是1×5厘米。胆管工程学已从多种途径进行了研究。(1)观察胆汁酸对胆管上皮细胞的损伤作用。胆汁酸对胆管上皮细胞的损伤作用小于对人腹膜间皮细胞的损伤。(2)将干扰素-γ基因导入上皮细胞和成纤维细胞。但未观察到干扰素-γ的分泌。(3)我们正在制备胆管癌细胞上皮细胞与人胆管癌细胞株相互交换的胆管癌细胞模型。(4)为了将人工导管应用于外科植入物，我们测试了人工导管的机械强度。该导管对管腔压力耐受性良好，但不能耐受机械应力。为克服胶原凝胶人工胆管在移植缝合过程中容易撕裂的问题，我们制备了组织相容的胶原网，并将其附着在结缔组织的底部。人工胆管制备的难题之一是难以大量培养胆管上皮细胞。我们正在开发一种新的培养方法，利用微重力培养条件获得结缔组织上种植大量胆管上皮细胞的三维组织。

Artificial bile duct may be useful as surgical material and for studying the pathological and therapeutic mechanisms of biliary disease such as bile duct cancer. We reconstituted 3-dimensional artificial bile duct consisting biliary epithelial monolayer and connective tissue sub-layer. We first prepared a tubular structured tissue composed of human fibroblast and collagen gel using a tubular glass mold composed of a mandrel and a sheath. Then, a hybrid tissue with a hierarchical structure was constructed by seeding human biliary epithelial cells and the tubular tissue. The greatest size of the artificial bile duct that we have made before is 1 X 5 cm. The engineering of bile duct has been studied from a variety of approaches. (1) We examined if bile acid can injure the epithelium of the duct. The morphological injury effect of bile acid is less on biliary epithelium than in human mesothelial cells. (2) We transfected IFN-γ gene to the epithelium and fibroblast. However, IFN-γ secretion could not be observed. (3) We are now preparing bile duct cancer model exchanging the epithelium to human bile duct cancer cell line. (4) To apply the artificial duct for surgical implantation, we tested the mechanical strength. The duct tolerated luminal pressures well but not the mechanical stress applied during an anasotmotic procedure. To overcome the problem that artificial bile duct of collagen gel was torn easily during suturing of grafting, we prepare histocompatible collagen mesh and attached the mesh to the bottom of the connective tissue. One of the problems of preparing artificial bile duct is a difficulty in culturing a large number of biliary epithelial cells. We are now developing a new culture method using microgravity culture condition to obtain the 3-dimensional tissue seeded by a large number of biliary epithelial cells on connective tissue.