Urethral Reconstruction with Small Intestinal Submucosa Seeded with Oral Keratinocytes and TIMP-1 siRNA Transfected Fibroblasts in a Rabbit Model.

Background: To evaluate the effect of tissue inhibitor of metalloproteinase-1 small interfering RNA (TIMP-1 siRNA) transfected fibroblasts (FB) for urethral reconstruction. Materials and Methods: A ventral urethral mucosal defect was created. Substitution urethroplasty was performed with small intestinal submucosa (SIS) alone (8 rabbits, group 1), autogenic oral keratinocytes (OK)-seeded SIS (8 rabbits, group 2) or autogenic OK and TIMP-1 siRNA transfected FB-seeded SIS (8 rabbits, group 3). At 1 and 6 months after surgery (4 rabbits at each time point), retrograde urethrogram and histologic analysis were performed to evaluate the outcomes of urethroplasty. Results: TIMP-1 siRNA transfected FB decreased the secretion of type I collagen. Under retrograde urethrography, 5 rabbits in group 1, 6 in group 2 and 7 in group 3 maintained a wide urethral caliber. Histologically, inflammation and fibrosis were observed at 6 months in group 1. The speed of urothelium, smooth muscle and vessel regeneration in group 3 was faster than that in group 2. Comparison of smooth muscle-to-collagen ratio, epithelial layers, smooth muscle content and microvessel density among three groups revealed a significant increase (p < 0.05). Conclusions: TIMP-1 siRNA transfected FB could be used as a source of seed cell for urethral tissue engineering and could prevent the proliferation of urethral scar tissue. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]