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 of cells. This technology is favored because cells from a patient can be used on that same individual, ruling out the typical occurrence of immune reaction, in which the patient's body rejects cells that are not his or her own. For example, patients receiving organ transplants often must take immunosuppressive drugs to ward off their body's immune reaction to the foreign tissue. However, when using one's own stem cells to generate cells or organs to replace one's damaged tissues, this immune response does not occur. This is a major benefit of adult stem cell therapy.
Embryonic stem cell therapy involves using cells from an embryo to create new types of cells or new organs that can be used to replace defective or damaged cells in a patient. Cells from an early-stage embryo are harvested and treated with chemicals until they become the needed cell type. As with adult stem cell therapy, these cells are cultured...