The peritoneal cavity as a bioreactor for tissue engineering visceral organs: bladder, uterus and vas deferens.

Our objective was to produce avascular, myofibroblast-rich tissue capsules for use as autologous grafts for hollow, smooth muscle-walled visceral organs-bladder, uterus and vas deferens. To produce tissue for grafting, templates of the appropriate shape were implanted in the peritoneal cavities of rats or rabbits. After 2-3 weeks, the templates were removed, the encapsulating myofibroblast-rich tissue harvested and grafted to replace resected segments of bladder, vas deferens or uterus of the same animals in which the tissue was grown. Bladder grafts showed 100% patency after 14 months and had developed a morphology similar to normal bladder. Tubes of myofibroblast tissue grafted unilaterally into resected rabbit vasa deferentia developed a morphology resembling native tissue, with sperm in the ejaculate indicative of normal function. At 12 weeks after grafting, uterine graft tissue had increased in thickness and developed the morphology of normal uterus, with endometrium overlying several layers of smooth muscle cells (myometrium-like) which were interspersed with collagen fibrils; grafted uterine horns supported embryos to the late stages of gestation. This study shows that myofibroblast tissue produced in the peritoneal cavity is sufficiently plastic to permit differentiation of cells into bladder, vas deferens or uterine smooth muscle. As a method for producing autologous graft material for repair/replacement of these organs, this approach has many benefits over conventional and current tissue-engineering strategies.