You've probably heard about stem cells on science blogs, newspaper articles, or even on social media! You must also be aware of the claims that stem cells are "miracle cells," "life-giving," and even capable of curing cancer. Well, you heard it right. Stem cells are capable of doing all that but how do they function? Well, it all comes down to the various sources of stem cells. The characteristics of stem cells usually vary depending on the source from which they're extracted. So are you ready to learn about stem cells, their classifications and applications? Let’s start with the definition of stem cells!
The term stem cells was first coined by William Sedgwick in 1886, to define the “regenerative quality” of plants. 1 They’re defined as multipotent cells that can differentiate into muscle cells, red blood cells, brain cells, heart muscle cells, and bone cells. 2
Let’s take a look at the different categorization of stem cells in the following section:
Depending on the sources of stem cells, they are divided into the following types:
Stem cells that are retrieved from human embryos are about 4-7 days old, post-fertilization. Naturally, these cells are pluripotent (have the ability to develop into any kind of cells and tissues). Embryonic stem cells are harvested via in-vitro fertilization, due to ethical reasons. 5, 6
In addition to being pluripotent, these cells have other special properties, such as self-renewal, structural repair and growth, and rapid cell division. Clinical applications of embryonic stem cells (developed from iPSCs/ Adult stem cells) have shown therapeutic potential and are considered in the management of diabetes and cardiovascular diseases. 7, 8
Researchers have discovered a way wherein adult human cells could be reprogrammed to mimic the qualities of embryonic stem cells, in the form of induced pluripotent stem cells (iPSCs). 9
These stem cells are extracted from a fetus and can be harvested from an embryo after the 8th week. Fetal stem cells may be taken from the fetal blood, bone marrow, or other fetal tissues such as liver and kidneys. 10
In comparison to adult stem cells, fetal stem cells are known to have better intrinsic engraftment, greater multipotency, and lower immunogenicity. 11
Adult stem cells (ASCs) are pluripotent cells that can regenerate, replacing the damaged or dead tissue. They can be found in some of the body's differentiating tissues. 12 ASCs' primary job in our bodies is to constantly repair, regenerate, and replace the cells that need to be replenished. Only 3 types of cells—neural cells, mesenchymal stem cells, and hematopoietic stem cells—can develop from adult stem cells.13
These stem cells are retrieved from the umbilical cord blood (and placenta) of a newborn. 14 Umbilical cord blood contains hematopoietic stem cells that is used to treat numerous genetic diseases, cancers, as well as inherited disorders. 15
So far, we’ve discussed the categorization based on different sources of stem cells. Now, let’s take a look at how stem cells are categorized based on their differentiation potential.
Totipotent stem cells have the ability to differentiate into any cell. The zygote formed during egg fertilization is among its best examples, because, it can grow into any type of cell, including the placental cell. 3 The only totipotent stem cells in the human body are those formed by embryonic cells following the first couple of cell divisions. 16
Embryonic stem cells are considered pluripotent because they can differentiate into any type of cell, with the exception of placental cells. Furthermore, pluripotent stem cells are produced in the initial stages of embryonic stem cell differentiation. However they can also be derived from the germ layers (a group of cells found in embryo during its development) 17 , which include the mesoderm, ectoderm, and endoderm.18, 6,19
Multipotent stem cells are present in almost all the tissues. MSCs or Mesenchymal stem cells are the most common example of multipotent stem cells. These stem cells can be extracted from adipose tissue, bone marrow, peripheral blood and even umbilical cord blood. 20
After learning about the various types of stem cells, you might be curious about their applications. Here we’ve enumerated few uses of stem cells (some of which are still in initial research stage):
Did you know? The advances in modern medical science has made it possible for new parents to preserve the stem cells from their baby's umbilical cord blood? Yes, you heard us right. This advancement is called stem cell banking and it offers protection and care (from the potential diseases and disorders) of the newborn as well as the entire family (including siblings, biological parents, and maternal and paternal grandparents).
Are you an expectant parent who wants to know more about the benefits of stem cell banking? Then all you have to do is give us a call @ 1800-266-5533!
If you wish to discover more fun facts about umbilical cord blood stem cells and the diseases it can cure, then do check out our “also read” section as well. Happy reading!