Attributes of adult stem cells

While cultured embryonic stem (ES) cells can be harvested in abundance and appear to be the most versatile of cells for regenerative medicine, adult stem cells also hold promise, but the identity and subsequent isolation of these comparatively rare cells remains problematic in most tissues, perhaps with the notable exception of the bone marrow. The ability to continuously self‐renew and produce the differentiated progeny of the tissue of their location are their defining properties. Identifying surface molecules (markers) that would aid in stem cell isolation is a major goal. Considerable overlap exists between different putative organ‐specific stem cells in their repertoire of gene expression, often related to self‐renewal, cell survival and cell adhesion. More robust tests of ‘stemness’ are now being employed, using lineage‐specific genetic marking and tracking to show production of long‐lived clones and …