Stem cells are the body's unspecialized cells: cells that can make copies of themselves and can also produce the specialized cells that make up blood, bone, muscle, fat and other tissue. Every other cell in your body started from one.
That pair of abilities is what the name means. A stem cell sits at the base of a family tree of cells, the way a trunk sits under its branches. This article covers what sets stem cells apart, where they live, and the main types scientists and doctors talk about.
What makes stem cells different from other cells
Most cells in an adult body are specialists: a red blood cell carries oxygen, and a skin cell forms a barrier. Once a cell takes on a job like that, it keeps it for the rest of its life.
Two abilities set stem cells apart from the specialists:
- Self-renewal. A stem cell can divide and make another stem cell, so the supply does not run out.
- Differentiation. A stem cell can produce cells that go on to become a specialized type, such as a bone cell or a fat cell.
Scientists also sort stem cells by how many cell types they can produce, a property called potency. Scientists call a cell that can produce any cell type in the body pluripotent. They call a cell that produces several related types, such as the different cells in blood, multipotent. The type of stem cell decides its potency, and its potency decides how researchers and doctors use it.
Where stem cells are found in the body
Stem cells are not one cell in one place. Adults carry small numbers of them in many tissues, where they replace cells that wear out:
- Bone marrow holds the stem cells that make every type of blood cell, millions of new cells each second.
- Fat tissue and bone marrow both hold mesenchymal stem cells, which can produce bone, cartilage and fat cells.
- Skin and the lining of the gut hold stem cells that replace those surfaces every few weeks.
Tissue donated after a healthy, full-term birth is also rich in stem cells. With the mother's consent, a provider collects it after the delivery, with no harm to mother or baby.
The main types of stem cells
When people talk about stem cells, they usually mean one of five types. Each one comes from a different source and has a different range of cells it can produce.
Pluripotent stem cells
Pluripotent stem cells can produce any cell type in the body. In nature they exist only for a few days at the very start of human development, and their use stays mostly in research labs. GIOSTAR uses no embryos.
Adult stem cells
Adult stem cells, also called tissue-specific stem cells, live in the tissues of a grown body. Each kind mostly produces the cells of its own tissue. The best known are blood-forming stem cells in the bone marrow. Hospitals have used them in bone marrow transplants since the late 1960s, the oldest established use of stem cells in medicine.
Mesenchymal stem cells
Mesenchymal stem cells are a kind of adult stem cell found in bone marrow, in fat, and in tissue donated after a healthy, full-term birth. Scientists first described them in the 1970s. In the lab, they can produce bone, cartilage and fat cells, and they release signaling molecules that other cells respond to.
Regenerative medicine uses this type more than any other, and it is the type GIOSTAR uses. Researchers sometimes call them mesenchymal stromal cells; the two names describe the same cells.
Donor stem cells
Donor stem cells come from one person and go to another. In regenerative medicine, the most common donor source is tissue donated after a healthy, full-term birth, with the mother's consent. That tissue is otherwise discarded after the delivery. Every donor goes through screening and testing before any tissue goes into use.
Induced pluripotent stem cells
Induced pluripotent stem cells, or iPS cells, start as ordinary adult cells, such as skin cells. Scientists reprogram them in a lab until they become pluripotent, able to produce any cell type. Shinya Yamanaka's team first made them in 2006, and the discovery earned a Nobel Prize in 2012. Today they are mostly a research tool.
How the types of stem cells compare
| Type | Where it comes from | What it can produce |
|---|---|---|
| Pluripotent | The first days of human development | Any cell type in the body |
| Adult (tissue-specific) | Bone marrow, skin, gut and other tissues | Mostly the cells of its own tissue |
| Mesenchymal | Bone marrow, fat, tissue donated after a healthy birth | Bone, cartilage and fat cells |
| Donor | Screened donors, most often after a healthy birth | Depends on the cell type collected |
| Induced pluripotent | Adult cells reprogrammed in a lab | Any cell type in the body |
Why stem cells matter in medicine
Stem cells matter because they are the body's own system for making new cells. Hospitals have relied on blood-forming stem cells for decades. Scientists study the other types to learn how tissues grow, how they wear down, and how cells signal to each other.
Regenerative medicine is the field built around that work. It uses cells and the materials cells release, such as exosomes, to support the body's own processes. Read more in what regenerative medicine is and what stem cell therapy is.
Stem cells at GIOSTAR
GIOSTAR stands for Global Institute of Stem Cell Therapy and Research. Our Henderson wellness center gives ethically sourced mesenchymal stem cells from screened donors, by injection or IV.
The cells come from tissue donated after healthy, full-term births, with the mother's consent. We use no embryos, and no harm comes to mother or baby. Every donor goes through screening and testing before any tissue goes into use, and every lot comes with a Certificate of Analysis and full traceability.
If you would like to know whether stem cell therapy at GIOSTAR fits your plans, your first step is a free consultation with our patient team. Your nurse practitioner then meets you in person, reviews your health history and answers your questions about the cells.
