Adult Stem Cell Plasticityn William B. Slayton and Gerald J. Spangruden n Spermatogonial Stem Cellsn Dirk G. de Rooijn n Stem Cells in Skeletal Musclen Anna Polesskaya and Michael Rudnickin n Gene Therapy Using Muscle-Derived Stem Cellsn Christopher Chermansky, Johnny Huard, and Michael B. Chancellorn n Human Dental Pulp Stem Cells: Characterization and Developmental Potentialn Stan Gronthos, Natasha Cherman, Pamela Gehron Robey, and Songtao Shin n Epithelial Stem/Progenitor Cells in Thymus Organogenesisn Hans-Reimer Rodewaldn n Adult Liver Stem Cellsn William B. Coleman, Joe W. Grisham, and Nadia N. Maloufn n Endothelial Progenitor Cellsn Takayuki Asahara and Jeffrey M. Isnern n Prostate Epithelial Stem Cellsn Anne T. Collins and David E. Nealn n Mammary Epithelial Stem Cellsn Elizabeth Anderson and Robert B. Clarken n From Marrow to Brainn Josef Prillern n Adult Retinal Stem Cellsn Monica L. Vetter and Edward M. Levinen n Multipotentiality of Iris Pigment Epithelial Cells in Vertebrate Eyen Mitsuko Kosaka, Guangwei Sun, Masatoshi Haruta, and Masayo Takahashin n Stem Cell Biology of the Inner Ear and Potential Therapeutic Applicationsn Thomas R. Van De Water, Ken Kojima, Ichiro Tateya, Juichi Ito, Brigitte Malgrange, Philippe P. Lefebvre, Hinrich Staecker, and Mark F. Mehlern n Engineering the In Vitro Cellular Microenvironment for the Control and Manipulation of Adult Stem Cell Responsesn Ali Khademhosseini and Peter W. Zandstran n Stem Cells As Common Ancestors: Somatic Cell Phylogenies From Somatic Sequence Alterationsn Darryl Shibatan n Index
Studies on stem cells have been attracting intense scientific and p- lic attention, not only because of controversies surrounding the use of embryonic stem cells but also because of very provocative data that have been emerging on adult stem cells. Much of the public attention and debate has been focused on the possibility that adult stem cells may be used as a substitute for human embryonic stem cells or as a justification for stopping work on them. This has somewhat dim- ished attention on very heated scientific debates that take us to the very heart of how the concept of stem cells is perceived. To this author, the latter debates have not been unlike certain philosophical debates of the last century. Since the seminal studies of Till and McCulloch in the 1960s, the popular paradigm on adult stem cells has been that lineage-restricted stem cells are derived from pluripotent stem cells very early during development. To many, and consistent with much data, the restriction to particular lineages was considered absolute. In other words, there was a sense of determinism in the stem quality of particular stem cells: once they were allocated, they were programmed to specific roles in a given tissue. Furthermore, some adult tissues were considered devoid of detectable stem cell presence or activity.