Unhealthy Stem Cells: When Health Conditions Upset Stem Cell Properties

The stem cell field has grown very rapidly during the last decade, offering the promise of innovative therapies to treat disease. Different stem cell populations have been isolated from various human adult tissues, mainly from bone marrow and adipose tissue, but many other body tissues harbor a stem cell population. Adult tissue stem cells are invariably found in discrete microenvironments termed niches, where they play key roles in tissue homeostasis by enabling lifelong optimization of organ form and function. Some diseases are known to strike at the stem cell population, through alterations in their specific microenvironments, making them non-viable. Furthermore, it has been shown that a transformed stem cell population could prompt the development of certain cancers. This review focuses on the potential negative aspects of a range of diseases on the activity of stem cells and how their potential use in cell therapies may be affected.