ABSTRACT
Various cell sources have been considered for tissue engineering and regenerative medicine. The most versatile category is pluripotent embryonic stem cells derived from human embryos (hES cells), which in principle can give rise to the more than 200 known adult human cell types derived from all three germ layers.1 The sourcing of hES cells has raised ethical debates, however, and it would be difcult to obtain enough lines to permit histocompatibility matching for most potential recipients. Recent reports of methods to generate induced pluripotent stem (iPS) cells from specialized cells, such as skin broblasts, show that it may be possible to generate cell lines that would have the same broad potential for multilineage differentiation as hES cells from any individual.2 However, undifferentiated hES and iPS cells have the potential to form teratomas. Therefore, ensuring the absence of residual stem cells in engineered tissue remains a hurdle to effective clinical implementation. Moreover, the cost of generating and characterizing individual iPS cell
CONTENTS
20.1 Introduction ................................................................................................ 419 20.2 Stem/Progenitor Cells Derived from the Genitourinary Tract ........... 421
20.2.1 Urine ................................................................................................ 421 20.2.2 Bladder .............................................................................................426 20.2.3 Kidney .............................................................................................426 20.2.4 Testis ................................................................................................427
