Engineered Tissues: A Bright Perspective in Urethral Obstruction Regeneration.

The urethral reconstruction using tissue engineering is a promising approach in clinical and preclinical studies in recent years. Generally, regenerative medicine comprises cells, bioactive agents, and biomaterial scaffolds to reconstruct tissue. For the restoration of extended urethral injury are incorporated autologous grafts or flaps from the skin of the genital area, and buccal mucosa are also utilized. However, biomaterial grafts with cells or growth factors are investigated to enhance these grafts. Natural and synthetic biomaterials were investigated for preclinical studies in the form of decellularization tissues, nanofiber/microfiber, film, and foam grafts that determined safety and efficiency. In this regard, skin grafts, bladder epithelium, buccal mucosa, small intestinal submucosa, tissue-engineered buccal mucosa, and polymeric nanofibers in clinical trials were examined, and promising and diverse outcomes were acquired. Even though one of the challenges of the reconstruction of the urethra is resistance to urine pressure and its ability to be sutured, it could be solved by the proper adjustment of the physicochemical characteristics of the graft. Urethral engineering faces challenges due to necrosis caused by a lack of angiogenesis and fibrosis, which require further investigation in future studies.