|A brief look at the different types of Stem Cells and their comparisons. You can click on the image for a larger view|
The ISSCR has published a large list of the various TYPES of stem cells, and it warrants a closer look at them to develop a deeper understanding of what they are.
1. Adult Stem Cells or Tissue-specific Stem CellsMany adult tissues contain stem cells that can replace cells that die or restore tissue after injury. Skin, muscle, intestine and bone marrow, for example, each contain their own stem cells. In the bone marrow, billions of new blood cells are made every day from blood-forming stem cells.
Adult stem cells are tissue-specific, meaning they are found in a given tissue in our bodies and generate the mature cell types within that particular tissue or organ. It is not clear whether all organs, such as the heart, contain stem cells. The term ‘adult stem cells’ is often used very broadly and may include fetal and cord blood stem cells.
There are a few stem cell therapies that are widely accepted by the medical community and these use tissue-specific stem cells. These are bone marrow or cord blood stem cell transplantation to treat diseases and conditions of the blood or to restore the blood system after treatment for specific cancers, skin stem cell therapies for burns and limbal stem cells for corneal replacement. In each case, the stem cells repair the same tissue from which they came.
Another type of adult stem cell is the mesenchymal stem cell. These are found in a number of tissues, including bone marrow, and may be able to produce bone, cartilage and fat. It is also possible that these or similar cells may aid in the regeneration of tissues. Extensive animal studies are currently ongoing to determine if these cells may be used for treatment of diseases such as arthritis and non-healing bone fractures. It is also possible that these or similar cells modulate the immune system in response to injury.