Tissue engineering in urethral reconstruction.

Urethral strictures are one of the most common urological problems, yet the natural limitations of wound healing and the physiologic demands on the anatomic structures combine to also make urethral strictures one of the most challenging urological problems to manage. Proper wound healing demands well approximated edges because prolonged inflammation and granulation, required to close large, deep wounds, will result in excess collagen production, fibrosis, and the formation of a scar or, in the urethra, a stricture. Biomaterials have successfully been used to approximate the ECM of several different tissue types and can define a three dimensional space suitable for the formation of new tissues with both appropriate structure and appropriate function. Biomaterials can be broadly categorized as either synthetic polymers or tissue matrices, each with their advantages and limitations. Recent studies utilizing cell seeded natural biomaterials in urethral repair has yielded some promising results. However, advancements in the use of alternative sources of cells for matrix seeding and cell-seeded synthetic materials hold the possibility of even better results in the future.