Objective To compare the regenerative capacity of diseased bladder in a large animal model of bladder exstrophy with regeneration in healthy bladder using a highly porous collagen scaffold. Materials and Methods Highly porous bovine type I collagen scaffolds with a diameter of 32 mm were prepared. In 12 fetal sheep a bladder exstrophy was surgically created at 79 days' gestation. Lambs were born at full term (140 days' gestation). After 1 week the bladder lesion was reconstructed and augmented with a collagen scaffold (group 1). In nine normal newborn lambs the bladder was augmented with a collagen scaffold 1 week after birth (group 2). Functional (video-urodynamics) and histological evaluation was performed at 1 and 6 months after surgery. Results The survival rate was 58% in group 1 and 100% in group 2. Cystograms were normal in all lambs, besides low-grade reflux in both groups. Urodynamics showed comparable capacity between both groups and a trend to lower compliance in group 1. Histological evaluation at 1 month revealed a non-confluent urothelial layer, an immature submucosa, and initial ingrowth of smooth muscle cells. At 6 months both groups showed normal urothelial lining, standard extracellular matrix development, and smooth muscle cell ingrowth. Conclusions Bladder tissue regeneration with a collagen scaffold in a diseased bladder model and in healthy bladder resulted in comparable functional and histological outcome, with a good quality of regenerated tissue involving all tissue layers. Improvements may still be needed for larger augmentations or more severely diseased bladders.

bladder exstrophy, collagen scaffold, diseased bladder, sheep, tissue engineering
dx.doi.org/10.1111/bju.12591, hdl.handle.net/1765/88830
BJU International
Department of Gynaecology & Obstetrics

Roelofs, L.A.J, Kortmann, B, Oosterwijk, E, Eggink, A.J, Tiemessen, D.M, Crevels, A.J, … Feitz, W.F.J. (2014). Tissue engineering of diseased bladder using a collagen scaffold in a bladder exstrophy model. BJU International, 114(3), 447–457. doi:10.1111/bju.12591