How are stem cells harvested from each of the stem cell sources?
Stem cells and progenitor cells specific to a tissue are in very small numbers in all organ sites where there presence has been defined. Stem cells from blood are usually enriched by “calling up” cells from the bone marrow using specific growth factors. The patient is pre-treated, several days later blood is collected and the cells are separated from the blood plasma, then further purified using a variety of separation and purification methods. Cells from solid organ sites such as fat, skin, and bone marrow often need to be treated with enzymes or other agents that separate the cells from other cells and/or the cell matrix which holds them in place in the tissue. Although this is significant manipulation many of the techniques have been developed and improved over many years. What is becoming more clear are the cell-associated biomarkers that define what is an omnipotent, pluripotent, multipotent or progenitor cell from the various organ sites and what is universally or specifically ap
