Stem cell technology is a field of medical research studying human and animal stem cells. Stem cells are naturally occurring cells essential to the growth and regeneration of organisms. Stem cells are already used for therapeutic purposes, and research suggests potential future benefits of stem cells in many fields of medicine. This research is controversial, however, because some such technology involves the use of human embryos.
Stem cells occur in all multi-cellular organisms. They are capable of transforming into any of the specialized cells necessary for the growth and maintenance of organs. In developing embryos, they become the cells necessary for the formation of various organs. In later life, they replenish these organs by replacing dead or diseased cells. One of the functions of stem cell technology is to achieve better understanding of this complex process.
Stem cells in bone marrow replenish a body’s supply of blood cells. Bone marrow transplants, a common treatment for leukemia patients, are one form of stem cell technology. Some scientists believe that similar uses of stem cells could eventually treat diseases as diverse as diabetes, nerve disease, Alzheimer’s and hearing loss. If genetic research can explain the functioning of stem cells, they could theoretically be used to replace cells damaged or destroyed by these diseases.
It is not clear if stem cell technology will be able to overcome the potential drawbacks to such treatment. For example, stem cells can actually create cancers if they are permitted to grow in an organism without regulation. Tissue rejection is also an issue, as it is with any organ transplant, if the source of the stem cells is someone other than the patient. Use of adult stem cells from elsewhere in the patient’s body could overcome these issues, but these possibilities remain to be explored.
Much research in stem cell technology is carried out using stem cells from animals such as mice. Human stem cells are sometimes taken from frozen embryos saved from practices such as in vitro fertilization. These embryos are no longer needed and are used with permission from the donor. The practice remains controversial, however, because many people believe these embryos constitute a living human being.
Scientists discovered in 2007 how to synthesize stem cells, called induced pluripotent stem cells, from other cells through gene manipulation. This has the potential to allow therapeutic stem cell use without involving embryos. It is not a perfect solution, because cancer remains a risk, but such cells harvested from the patient may not be prone to tissue rejection. Stem cell technology is still in its infancy, but the potential benefits to humankind could be enormous.