- Fat-Fighting Foods Slideshow
- Take the Human Body Quiz
- Causes of Fatigue Slideshow Pictures
- Patient Comments: Stem Cells - Experience
- Stem cell facts
- What are stem cells?
- Why are stem cells important?
- Embryonic stem cells
- Fetal stem cells
- Adult stem cells
- Peripheral blood stem cells
- Umbilical cord stem cells
- Induced pluripotent stem cells
- Why is there controversy surrounding the use of stem cells?
- What are some stem cell therapies that are currently available?
- What are experimental treatments using stem cells and possible future directions for stem cell therapy?
Why are stem cells important?
Stem cells represent an exciting area in medicine because of their potential to regenerate and repair damaged tissue. Some current therapies, such as bone marrow transplantation, already make use of stem cells and their potential for regeneration of damaged tissues. Other therapies that are under investigation involve transplanting stem cells into a damaged body part and directing them to grow and differentiate into healthy tissue.
Embryonic stem cells
During the early stages of embryonic development the cells remain relatively undifferentiated (immature) and appear to possess the ability to become, or differentiate, into almost any tissue within the body. For example, cells taken from one section of an embryo that might have become part of the eye can be transferred into another section of the embryo and could develop into blood, muscle, nerve, or liver cells.
Cells in the early embryonic stage are totipotent (see above) and can differentiate to become any type of body cell. After about seven days, the zygote forms a structure known as a blastocyst, which contains a mass of cells that eventually become the fetus, as well as trophoblastic tissue that eventually becomes the placenta. If cells are taken from the blastocyst at this stage, they are known as pluripotent, meaning that they have the capacity to become many different types of human cells. Cells at this stage are often referred to as blastocyst embryonic stem cells. When any type of embryonic stem cells is grown in culture in the laboratory, they can divide and grow indefinitely. These cells are then known as embryonic stem cell lines.