These daughter cells become either new stem cells or specialized cells (differentiation) with a more specific function, such as blood cells, brain cells, heart muscle cells or bone cells. No other cell in the body has the natural ability to generate new cell types. .What are adult stem cells?Adult stem cells are cells that have the ability to continuously divide and create more specialized cells with more complex functions. In other words, these mature,
non-dividing cells can be coaxed into becoming a range of cell types. Scientists have identified certain adult stem cells in most body tissues, including bone marrow and several types of fat tissue. All human beings have the potential for generating adult stem cells; however they tend to be scarce in some tissues
What are the different types of stem cells?
There are three types of stem cells: embryonic stem cells, adult stem cells and induced pluripotent stem cells.
Embryonic stem cells are obtained from the inner cell mass of an embryo. These types of cells have the potential to differentiate into any type of cell in the body. Adult stem cells are found in specific organs and tissues throughout the body, including bone marrow, blood, skin, brain and spinal cord. They can also produce any type of cell in the body but they have a more limited capacity to do so than embryonic stem cells. Induced pluripotent stem (iPS)cells are created by taking skin or blood samples from an individual's adult tissue and treating them with a combination of chemicals that cause them to revert back to their original state as embryonic-like pluripotent stem cells.
Where do stem cells come from?
There are several sources of stem cells:
- Embryonic stem cells. These stem cells come from embryos that are 3 to 5 days old. At this stage, an embryo is called a blastocyst and has about 150 cells.
These are pluripotent (ploo-RIP-uh-tunt) stem cells, meaning they can divide into more stem cells or can become any type of cell in the body. This versatility allows embryonic stem cells to be used to regenerate or repair diseased tissue and organs. - Adult stem cells. These stem cells are found in small numbers in most adult tissues, such as bone marrow or fat. Compared with embryonic stem cells, adult stem cells have a more limited ability to give rise to various cells of the body.
Until recently, researchers thought adult stem cells could create only similar types of cells. For instance, researchers thought that stem cells residing in the bone marrow could give rise only to blood cells.
However, emerging evidence suggests that adult stem cells may be able to create various types of cells. For instance, bone marrow stem cells may be able to create bone or heart muscle cells.
This research has led to early-stage clinical trials to test usefulness and safety in people. For example, adult stem cells are currently being tested in people with neurological or heart disease. - Adult cells altered to have properties of embryonic stem cells. Scientists have successfully transformed regular adult cells into stem cells using genetic reprogramming. By altering the genes in the adult cells, researchers can reprogram the cells to act similarly to embryonic stem cells.
This new technique may allow use of reprogrammed cells instead of embryonic stem cells and prevent immune system rejection of the new stem cells. However, scientists don't yet know whether using altered adult cells will cause adverse effects in humans.
Researchers have been able to take regular connective tissue cells and reprogram them to become functional heart cells. In studies, animals with heart failure that were injected with new heart cells experienced improved heart function and survival time. - Perinatal stem cells. Researchers have discovered stem cells in amniotic fluid as well as umbilical cord blood. These stem cells have the ability to change into specialized cells.
Amniotic fluid fills the sac that surrounds and protects a developing fetus in the uterus. Researchers have identified stem cells in samples of amniotic fluid drawn from pregnant women for testing or treatment — a procedure called amniocentesis.
Ref:
- https://en.wikipedia.org/wiki/Stem_cell,
- https://cell-lavie.com/,
- https://www.mayoclinic.org/
Source: Cell La vie