Bile Duct Regeneration Using a Gelatin Hydrogel Nonwoven Fabric-Based Artificial Bile Duct in Pigs

BACKGROUND: Bile duct jejunal anastomosis is a standard reconstruction method following bile duct resection. Nevertheless, this procedure is technically intricate and carries significant postoperative risks. This study evaluated bile duct regeneration in pigs using artificial bile ducts (ABDs) made of gelatin hydrogel nonwoven fabric (GHNF). EXPERIMENT: An ABD composed of polyglycolic acid (PGA) as the inner layer and GHNF as the outer layer was implanted in the defect of the bile duct in pigs. After a 105-day implantation period, tissue samples were analyzed via histology, immunohistochemistry, and RNA sequencing. RESULTS: The implantation of the ABD promoted fibroblast infiltration, extracellular matrix (ECM) formation, and bile duct epithelial regeneration in the site of the bile duct defect by postoperative day 105. Histological analysis revealed complete absorption and replacement of GHNF by collagen-rich ECM. Immunohistochemistry studies indicated the presence of CK19-positive bile duct epithelial cells in the ABD area, suggesting the successful regeneration of the entire bile duct structure. Furthermore, RNA sequencing revealed gene expression patterns analogous to those observed in native bile ducts, showing a similarity with a significant correlation coefficient between the regenerated and the native bile ducts. Differentially expressed genes related to ECM formation, such as COL3A1, SPARC, and COL1A1, were highly expressed, along with growth factors such as FGF1, FGF7, FGF18, FGF22, TGFβ1, and TGFβ3. CONCLUSIONS: The experimental findings demonstrated the successful regeneration of bile duct tissue by the ABD made of GHNF implanted in pigs, thereby signifying its potential for future clinical applications.