Some Basics on Adult Stem Cells

Some Basics on Adult Stem Cells

All information on this page is summarized from the website of the International Society for Stem Cell Research. Since it’s a relative slow news day (so far), I thought it might be useful to update the blog with some VERY basic information about non-embryonic stem cells. Any errors in the science are my own.

There are several types of stem cells besides embryonic stem cells that are being studied and/or used in therapies throughout the world.

Adult stem cells have different properties depending upon where they are derived from. Their ability to differentiate and the extent of such differentiation is still not well understood. This is a general class of cells, and includes the hematopoeitic and mesenchymal cells described below, as well as cells from a few other parts of the human body.

Hematopoietic stem cells are a type of adult stem cell produced by human bone marrow. They can be used to produce different kinds of blood cells, are easily obtained from bone marrow or directly from the blood, and have been used in therapies for blood cancers and other diseases for years. It is unknown at present if they can differentiate into cells other than blood cells. (See the 9-18-05 Post “Stem Cell Recipients Mostly Healthy 10 Years Later” for a discussion of a study on HCTs, or hematopoeitic cell therapies.)

Mesenchymal stem cells are also adult stem cells which are produced by the bone marrow, but they are able to differentiate into several different kinds of cells, including fat cells, muscles cells, bone and cartilage cells, tendon and ligament cells, skin cells, and nerve cells. (The ability to differentiate into a variety of cells is known as pluripotency.) They are easily cultured in the laboratory and can be preserved by freezing. Animal trials on tissue repair with mesenchymal stem cells have shown promise.

Umbilical cord stem cells (also known as neo-natal stem cells) are a different form of hematopoietic stem cells. They are obtained from the blood of a newborn infant’s umbilical cord and are less mature than stem cells obtained from the bone marrow of children or adults. In the treatment of blood cancers and diseases, cord blood grafts are less likely to produce an immune system response from the recipient than bone marrow grafts. However, the use of cord blood cells for tissue regeneration is probably subject to the same risk of rejection as organ donations.