Cellular and Molecular Biology



Adult stem and transit-amplifying cell location

L. Díaz-Flores Jr.1, J.F. Madrid2, R. Gutiérrez1, H. Varela1, F. Valladares1, H. Alvarez-Argüelles1 and L. Díaz-Flores1

1Deparment of Pathology, Histology and Radiology, School of Medicine, La Laguna University, Canary Islands and 2Department of Cell Biology, School of Medicine, University of Murcia, Murcia, Spain

Offprint requests to: L. Díaz-Flores, Departamento de Patología, Facultad de Medicina, Universidad de La Laguna, Tenerife, Spain. e mail: fvallapa@ull.es

Summary. Adult stem cells (ASC) -able to self renew and to intervene in maintaining the structural and functional integrity of their original tissue- can express greater plasticity than traditionally attributed to them, adopting functional phenotypes and expression profiles of cells from other tissues. Therefore, they could be useful to regenerative medicine and tissue engineering. Transit-amplifying cells (TAC) are committed progenitors among the ASC and their terminally differentiated daughter cells. The ASC reside in a specialized physical location named niche, which constitutes a three-dimensional microenviroment where ASC and TAC are protected and controlled in their self-renewing capacity and differentiation. The niche can be located near or far from the recruitment point, requiring a short or long-distance cellular migration, respectively. This paper briefly reviews the current status of research about ASC plasticity, transdifferentiation, fusion and functional adaptation mechanisms. Subsequently, ASC and TAC occurrence, characteristics and location have been considered in the skin, cornea, respiratory tract, teeth, gastrointestinal tract, liver, pancreas, salivary glands, kidney, breast, prostate, endometrium, mesenchyma, bone marrow, skeletal and cardiac muscle, nervous system and pituitary gland. Moreover, the role of cancer ASC has also been revised. Histol Histopathol 21, 995-1027 (2006)

Key words: Stem cells, Transit-amplifying cells, Skin, Cornea, Respiratory, Gastrointestinal, Prostate, Bone marrow, Nervous system, Pituitary

DOI: 10.14670/HH-21.995