There are two main types of stem cell therapy, that involving adult stem cells and that involving embryonic stem cells.
Adult stem cell technology is more advanced and has recently moved into the clinical trial stage (Bohlin, 2004). It involves removing stem cells from a patient's body or another adtlt's body, indubing them to become cells of a particular type, such as heart muscle cells, by treating them with chemicals, culturing them (growing them so they make more cells), and then inserting this new cell mass into a place in the patient's body where new tissue is needed. An example of this would be a situation where bone marrow stem cells are taken from an individual and induced to become lung cells, which are then cultured to produce a mass of lung cells. These would be inserted into a patient's lung to replace damaged tissue from lung cancer. Such therapies previously had encountered problems due to the difficulty of enticing adult stem cells to become other types of cells. The procedures previously available involved using cells of the organ in question to produce more cells of that same organ, such as using skin stem cells to grow more skin that could replace damaged skin on a burn victim. Recently, however, the technology has advanced to allow the use of stem cells to create other types o