A novel tubular construct using silk fibroin-chitosan scaffold seeded with bone marrow mesenchymal stem cells for...

To construct tissue-engineered tubular grafts (TETGs) using bone marrow mesenchymal stem cells (BMSCs) and silk fibroin/chitosan (SF/CS) scaffolds, and to evaluate their feasibility and efficacy for urinary diversion in a rabbit model.

BMSCs, smooth muscle cells (SMCs), and urothelial cells (UCs) were isolated and characterized in vitro. Differentiated BMSCs and SMCs were seeded onto SF/CS scaffolds for an additional week. The resulting TETGs were implanted for urinary diversion in the experimental group (n = 24), while acellular SF/CS grafts served as controls (n = 24). Histological and immunohistochemical analyses were performed at 1, 2, 4, and 8 weeks post-implantation. Outflow tract patency was assessed via intravenous urography (IVU) at 10 weeks.

BMSCs exhibited high expression of CD44 and CD90 and low expression of CD34 and CD45. BMSCs successfully differentiated into urothelium-like cells, expressing the urothelial-specific proteins uroplakin 1A (UP1A), cytokeratin 7 (CK7), and cytokeratin 13 (CK13). All rabbits in the experimental group survived, showing luminal urothelial growth, with complete epithelialization achieved by week 8. Immunohistochemistry confirmed the presence of mature and functional epithelial cells, as evidenced by positive staining for Anti-cytokeratin AE1/AE3, UP1A, and the tight junction protein ZO-1. IVU confirmed patent outflow tracts without stenosis, urinary fistula, hydronephrosis, or ureteral dilation. In contrast, control grafts collapsed by week 4, resulting in mortality.

BMSCs can serve as a viable cell source for urinary tissue engineering. The construction of a urinary diversion conduit using BMSC-derived urothelium-like cells and SF/CS is feasible in rabbits, demonstrating its potential for clinical application.