Growth of bone marrow stromal cells on small intestinal submucosa: an alternative cell source for tissue engineered bladder

OBJECTIVE To assess the potential use of bone marrow stromal cell (BMSC)‐seeded biodegradable scaffold for bladder regeneration in a canine model, by characterizing BMSCs and comparing them to bladder smooth muscle cells (SMCs) by immunohistochemistry, growth capability, and contractility. MATERIALS AND METHODS Bone marrow was taken by direct needle aspiration from the femurs of five beagle dogs for the in vitro study. Mononuclear cells were isolated by Ficoll‐Paque® density gradient centrifugation and cultivated in medium 199 with 10% fetal bovine serum. BMSCs were characterized by cell proliferation, in vitro contractility, immunohistochemical analysis, and the growth pattern on small intestinal submucosa (SIS) scaffolds compared to bladder SMC cultures from the same dogs. Another six dogs had a hemicystectomy and bladder augmentation with BMSC‐seeded (two), bladder cells including urothelial cells plus SMC‐seeded SIS (two) and unseeded SIS scaffolds (two). The six dogs were followed for 10 weeks after augmentation. RESULTS In vitro BMSCs had a significant contractile response to calcium‐ionophore, with a mean (sem) 36 (2)%, relative contraction (P