Human embryoid body-derived stem cells in co-culture with bladder smooth muscle and urothelium

Objectives. Human pluripotent stem cells have excellent regenerative abilities, making them attractive in bladder regeneration. Porcine small intestinal submucosa (SIS) is an established matrix well-suited to the urinary tract. We evaluated the ability of human embryonic germ (hEG) cell-derived stem cells to form a composite graft on SIS, grown alone or in combination with human bladder smooth muscle cells (SMCs) or urothelial (URO) cells. Methods. The hEG cell-derived cell line SDEC had the best-fit profile for smooth muscle, as determined by its gene and protein expression. SDEC cells were seeded on SIS, either on its serosal or mucosal surface, and cultured for 7 or 14 days. Co-cultures of stem cells with URO cells or SMCs were also assessed under similar conditions. The grafts were analyzed by histologic examination for cell growth, morphology, and matrix penetration. Results. SDEC cells grew in a monolayer on SIS, with a marked increase in three-dimensional growth when co-cultured with URO cells or SMCs. Penetration of the matrix was evident when seeded on the rough surface of the SIS, progressing with time. Stratification of the cell layers occurred on the smooth side of the SIS. Conclusions. This is the first description of hEG cell-derived stem cells in co-culture with bladder cells. hEG cell-derived stem cells grow well on SIS even when seeded at low concentrations in the presence of bladder cells (URO cells or SMCs). These composite grafts will be ideal to evaluate the in vivo functional characteristics of stem cells using an animal model of bladder regeneration.