Tissue engineering of a genitourinary tubular tissue graft resistant to suturing and high internal pressures

The aim of this study was to evaluate the possibility of constructing a fully autologous tissue-engineered tubular genitourinary graft (TTGG) and to determine its mechanical and physiological properties. Dermal fibroblasts (DFs) were expanded and cultured in vitro with sodium ascorbate to form fibroblast sheets. The sheets were then wrapped around a tubular support to form a cylinder. After maturation, urothelial cells (UCs) were seeded inside the DF tubes, and the constructs were placed in a bioreactor. The TTGGs were then characterized according to histology, immuno-histochemistry, Western blot, cell viability, resistance to suture, and burst pressure. Results obtained were encouraging on all levels. All layers of the TTGGs had merged, and a pluristratified urothelium coated the luminal surface of the tubes. The burst pressure of non-sutured TTGGs was measured and found to be, on average, three times as resistant as that of porcine urethras. Suturing was accomplished without difficulty. Results have shown that our construct can sustain an entire week of pulsatile stimulation without loss of mechanical or histological integrity. The tissue-engineering technique used to produce this model seems promising for bioengineering a urethra or ureter graft and could open a doorway to new possibilities for their reconstruction.