Stem cells are the foundation for every organ and tissue in your body. There are many different types of stem cells that come from different places in the body. These include Embryonic, Tissue Specific, Mesenchymal, and Induced pluripotent stem cells. Embryonic stem cells exist only at the earliest stages of development and various types of tissue-specific adult stem cells appear during fetal development and remain in our bodies throughout our life.
All stem cells can self renew and even develop into more specialized cells. Beyond these two critical abilities, though, stem cells vary widely in what they can and cannot do and in the circumstances under which they can and cannot do certain things. This is one of the reasons researchers use all types of stem cells in their investigations.
Embryonic stem cells
Embryonic stem cells forms three to five days after an egg cell is fertilized by a sperm. In normal development, these cells will give rise to the more specialized cells that give rise to the entire body, basically all of our tissues and organs. When scientists extract these cells, they retain the properties of embryonic stem cells.
Embryonic stem cells can give rise to every cell type in the fully formed body, but not the placenta and umbilical cord. These cells are incredibly valuable because they provide a renewable resource.
Tissue-specific stem cells
Tissue-specific stem cells or adult stem cells, are more specialized than embryonic stem cells. Typically, these stem cells can generate different cell types for the specific tissue or organ in which they live. Some tissues and organs within your body contain small caches of tissue-specific stem cells whose job it is to replace cells from that tissue that are lost in normal day-to-day living or in injury like those in your skin or blood among other things.
For example, blood-forming stem cells in the bone marrow can give rise to red blood cells, white blood cells and platelets. However, blood-forming stem cells don’t generate liver, lung or brain cells, and stem cells in other tissues and organs don’t generate red or white blood cells or platelets.
Mesenchymal stem cells
Mesenchymal which some call Stromal stem cell, refer to cells isolated from stroma, the connective tissue that surrounds other tissues and organs. The first cells of this type were discovered in the bone marrow and were shown to be capable of making bone, cartilage and fat cells.
Since then, they have been grown from other tissues, such as fat and cord blood. Various cells of this type are thought to have stem cell, and even immunomodulatory, properties and are being tested as treatments for a great many disorders, but there is little evidence to date that they are beneficial. Scientists do not fully understand whether these cells are actually stem cells or what types of cells they are capable of generating.
Induced pluripotent stem cells
Induced pluripotent stem cells are cells that have been engineered in the lab by converting tissue-specific cells, such as skin cells, into cells that behave like embryonic stem cells. These cells are critical tools to help scientists learn more about normal development and disease onset and progression. They are also useful for developing and testing new drugs and therapies.
Researchers are experimenting with many alternative ways to create these cells so that they can ultimately be used as a source of cells or tissues for medical treatments. While these cells share many of the same characteristics of embryonic stem cells, they aren’t exactly the same. Scientists are exploring what these differences are, what they mean and what they can be used for.