Different Kinds of Stem Cells

The political and scientific status of adult stem cells (also called mesenchymal stem cells, or MSCs) and embryonic stem cells (escs) is quite different and in need of constant clarification. Add to these two types of cells amniotic stem cells, recently discussed by Anthony Atala (Wake Forest) as another possible source of different- and still useful- cells that are normally discarded in amniotic fluid. But there are many more types. Even within our bone marrow, stem cells have begun to differentiate into subtypes. Catherine Verfaille has identified "multipotent" cells, that can make certain tissues such as muscle, cartilage & bone (MAP stem cells); but these cells cannot make, for example, liver or bladder. The different types of stem cells will eventually be classified based upon surface antigens or other biomarkers that give us an idea of what path they have already gone down...and what they can become.