Do current bladder smooth muscle cell isolation procedures result in a homogeneous cell population? Implications for bladder tissue engineering

Purpose Conventional techniques used to harvest and culture bladder smooth muscle cells (SMCs) have been thought to yield homogeneous populations of SMCs. In order to delineate the cellular composition of tissue derived bladder cells, this study was conducted to determine whether current culturing techniques result in a uniform population of bladder SMCs that may be utilized for bladder tissue engineering. Methods Patient derived bladder muscle was isolated and manually minced followed by enzymatic digestion. Cells were cultured in d -valine α-MEM with decreasing levels of fetal bovine serum then fixed and permeabilized for flow cytometric and immunofluorescent analyses. Antibody staining of cultured cells consisted of α-SMA, von Willebrand factor, pan-cytokeratin, CD31, and CD90. Cells were visualized using directly conjugated fluorescein isothiocyanate primary or IgG-Alexa-555 conjugated secondary antibodies. Results Flow cytometric analyses revealed mixed populations of cells expressing non-SMC epitopes as corroborated by immunofluorescent studies. High density oligonucleotide array analysis revealed expression levels of known bladder SMC genes and the expression of endothelial and fibroblast related markers ( P