Tissue engineering potential of urothelial cells from diseased bladders.

PURPOSE: We examined the suitability of urothelium from patients with abnormal bladders for use in surgical reconstruction using a tissue engineering approach that would require autologous urothelium to be expanded by propagation in cell culture.

MATERIALS AND METHODS: Resection specimens from 8 children (median age 9.8 years) with abnormal bladders (neuropathic in 4, posterior urethral valves in 2, epispadias in 1, nonneurogenic in 1) were collected with informed parental consent during planned urological procedures. Six patients had recurrent urinary tract infections and 7 underwent frequent intermittent catheterization. A representative sample was immunohistologically processed to assess urothelial proliferation and differentiation status, and the remaining 7 cases were processed for urothelial cell culture. Five normal adult urothelial samples were included as controls.

RESULTS: Immunohistological assessment indicated that 3 of 8 samples lacked urothelial differentiation associated expression of UPK3a or CK20. Four of 7 samples resulted in successful primary culture, with 1 sample lost to underlying infection and 2 not surviving in culture. All 4 cultures grew beyond passage 3 before senescence but all showed reduced proliferation capacity and a compromised ability to form a barrier urothelium compared to controls.

CONCLUSIONS: While normal human urothelium is highly regenerative and derived cells are highly proliferative in culture, our results with urothelium from abnormal pediatric bladders indicate a reduced capacity for proliferation and differentiation in vitro. This finding may indicate a need to identify alternative cell sources for engineered bladder reconstruction.