What are stem cells and why are they important?
Stem cells have the remarkable potential to develop into many different cell types in the body during early life and growth. In addition, in many tissues they serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell. Stem cells are distinguished from other cell types by two important characteristics. First, they are unspecialized cells capable of renewing themselves through cell division, sometimes after long periods of inactivity. Second, under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions. In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or da
The term “stem cell” is used to describe precursor cells that can become different tissue types. The categories of stem cells mentioned most commonly are embryonic stem cells and adult stem cells. A very early embryo is made up of embryonic stem cells that are pluripotent; that is, they can differentiate into all different cell types – cells that make up the brain, skin, bones, connective tissue, internal organs, eyes, fingernails, and everything else that comprises a fully developed human. Cells isolated from these embryos can be propogated indefinitely in culture, and can remain undifferentiated while retaining the ability to form any kind of cell. According to the National Institutes of Health, the potential for embryonic stem cells in medicine is “staggering.” Researchers have already used these cells to grow heart muscle cells that can beat in unison in a culture dish, blood vessel cells, bone, cartilage, neurons, and skeletal muscle. The great promise of embryonic stem cells is t
