Stem cells are cells that are able to differentiate into specialized cell types. Commonly, stem cells come from two main sources: embryos and adult tissue. Both types are potential to differentiate into different cell types (such as skin, muscle or bone). An important feature for stem cell is its asymmetric cell division, which means that when stem cell divides, one daughter cell remains as a stem cell and the other becomes a specialized cell.
- Adult or somatic stem cells exist throughout the body and are found inside of different types of tissue. Adult stem cells can divide or self-renew indefinitely, enabling them to generate a range of cell types from the originating organ. It is generally thought that adult stem cells are limited in their ability to differentiate based on their tissue of origin, but there is some evidence to suggest that they can differentiate to become other cell types. Nevertheless, the separating of somatic stem cells is very challenging.
- Embryonic stem cells are derived from a human embryo that is in the blastocyst phase of development. These so called totipotent cells have total potential to develop into any cell in the body. All the cells of our body are originally made from these cells. There are hard ethical questions in the use of embryonic stem cells and it's difficult to get them to specialize into a desired cell.
Medical researchers believe that stem cell therapy has the potential to dramatically change the treatment of human disease. A number of adult stem cell therapies already exist, particularly bone marrow transplants that are used to treat leukemia. In the future, medical researchers have great hope being able to use technologies derived from stem cell research to treat a wider variety of diseases. Fingers crossed!