Stem cells and differentiated cells differ in their sensitivity to urine in vitro.

Urinary tract regeneration using tissue engineering is one of the most challenging issues in the field of reconstructive urology. Cells seeded on scaffold are exposed to urine immediately after the implantation. The outcome of urinary bladder regeneration is depended on the ability of these cells to survive, proliferate, and regenerate. The aim of this study was to compare a sensitivity of three different cell lines to urine in vitro. Three different cell lines were isolated from porcine bladder (urothelial cells, UCs and smooth muscle cells, SMCs) and adipose tissue (adipose-derived stem cells, ADSCs). Cell viability (MTT assay), proliferation (real-time cell analysis using xCELLigence system) and apoptosis/necrosis (flow cytometry) were analyzed after exposition to urine. ADSCs were the most sensitive to urine compared to two other tested cell lines. Among the bladder cell lines the UCs were more resistant to urine than SMCs. Twenty four hour incubation of UCs, SMCs, and ADSCs with urine lead to ∼40%, ∼70%, and ∼90% reduction of their viability, respectively. The mechanism of urine mediated cytotoxicity differed depending on the tested cell type. Urothelial and SMCs seems to be more suitable for urinary bladder regeneration compared to mesenchymal stem cells, however, these cells have limited application especially in the case of urinary bladder cancer.