Stem cells are generally early stage cells that have the ability to continuously divide and differentiate (develop) into other specialized types of cells. For example, stem cells can turn into liver cells, skin cells, nerve cells etc. Like a blank microchip that can ultimately be programmed to perform any one of a number of specialized tasks, stem cells are undifferentiated cells that do not yet have a specific physiological function. When proper conditions occur in the body or lab, stem cells begin to develop into specialized tissues and organs. These cells may have differing abilities to turn into more specialized cells and are self-sustaining, replicating through cell division. These unique features are why stem cell research holds such promise for the treatment of life-threatening and debilitating diseases such as Alzheimer’s, cancer, Parkinson’s and juvenile diabetes.

There are two main categories of stem cells: embryonic and adult. Embryonic stem cells which are harvested from the inner cell mass of the blastocyst 7 – 10 days after fertilization and fetal stem cells which are taken from the germline tissues that will make up the gonads of aborted fetuses comprise embryonic stem cells. Adult stem cells can be extracted from many types of adult tissues such as fat, umbilical cord stem cells that come from the blood of umbilical cords after birth and placenta derived stem cells that have up to 10 times as many stem cells than from cord blood.

Finding out how cells store information and transform themselves into other cells with different properties is a fascinating topic for exploration. Stem cells are so named because cells are derived from a main stem or mother set of cells. This is similar to a tree trunk that provides the stem from which other cells grow and branch out into other types of cells.

Embryonic stem cells are technically called totipotent and produce all types of tissue and can produce an entire person (e.g. identical twins). Pluripotent stem cells exist in the undifferentiated inner cell mass of the blastocyst and can form any of over 200 different cell types found in the body. Multipotent stem cells are derived from fetal tissue, cord blood and adult stem cells. Although their ability to differentiate is more limited than pluripotent stem cells, they already have a track record of success in cell-based therapies. The recently fertilized egg in very early stages has only about 8 cells within it. The overall purpose of an embryonic stem cell is to grow into a baby. The inner cells called pluripotent can become almost any type of cell and are taken from very early embryos.

Adult stem cells are typically called multipotent cells like bone marrow cells that can produce a wide range of different blood cells. The primary purpose of an Adult stem cells is healing. Such cells can be collected from bone marrow, fat cells, or the lining of the nose, etc. Adult Stem cells can also be collected from umbilical cords of recently born babies. Some of these slightly undeveloped cells can be turned into other types of cells (multipotent). Chemical signals from nearby cells can direct the final cell type.