Full thickness skin wounds in humans heal with scars, but without regeneration of the dermis. A degradable poly(urethane urea) scaffold (PUUR), Artelon(R) is already used to reinforce soft tissues in orthopaedics, and for treatment of osteoarthritis of the hand, wrist and foot. In this paper we have done in vitro experiments followed by in vivo studies to find out whether the PUUR is biocompatible and usable as a template for dermal regeneration. Human dermal fibroblasts were cultured on discs of PUUR, with different macrostructures (fibrous and porous). They adhered to and migrated into the scaffolds, and produced collagen. The porous scaffold was judged more suitable for clinical applications and 4 mm Ø, 2 mm-thick discs of porous scaffold (12% w/w or 9% w/w polymer solution) were inserted intradermally in four healthy human volunteers. The implants were well tolerated and increasing ingrowth of fibroblasts was seen over time in all subjects. The fibroblasts stained immunohistochemically for procollagen and von Willebrand factor, indicating neocollagenesis and angiogenesis within the scaffolds. The PUUR scaffold may be a suitable material to use as a template for dermal regeneration.

To acquire urothelial cells for in vitro engineering of urothelium, biopsy specimens were taken from the urological tract. In clinical practice the number of cells harvested by biopsy are limited and the procedure requires general anaesthesia in children. The purpose of this study was to find out if bladder washings from adult patients as well as children contained enough proliferative and colony-forming uroepithelial cells to regenerate urethral mucosa in vitro, and if the cells could be stored by freezing. Bladder washings from nine children and eight adult patients were collected from patients who were having procedures that required an indwelling catheter. All cultures grew colonies of cells with a morphological appearance typical for epithelial cell growth. The cultures could be expanded to confluent, stratified sheets, and cells that stained for pancytokeratin, indicating an epithelial origin. Cells stored in -150 degrees C could be cultured and expanded in vitro. No differences were seen between cells from adults and children. Bladder washing is a non-invasive way to obtain many autologous urothelial cells. The method is reproducible and well tolerated by children. The possibility of culturing cells obtained in this way into stratified grafts provides a unique way of reconstructing the urogenital tract by "tissue engineering".

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